Integrated Forehead and Temporal Augmentation Using 3D Printing-Assisted Methyl Methacrylate Implants

Integrated Forehead and Temporal Augmentation Using 3D Printing-Assisted Methyl Methacrylate... Abstract Background Achieving aesthetic results with forehead augmentation procedures remains challenging. We have developed a method of integrated forehead and temporal augmentation using a three-dimensional (3D) printing-assisted methyl methacrylate implant. Objectives The study objective was to assess the importance of combined temporal augmentation when performing forehead augmentation. Methods We identified 34 patients (from 2000 to 2010) who underwent forehead augmentation with a methyl methacrylate implant contoured in situ during surgery and 41 patients (from 2010 to 2016) who underwent integrated forehead and temporal augmentation with a prefabricated methyl methacrylate implant. We conducted a retrospective chart review of patient data including operation time, complications, and instances of revision surgery. Two blinded plastic surgeons scored the aesthetic results of the operations on a 4-point scale (1, poor, to 4, excellent) based on preoperative and posttreatment photographs. Results The integrated augmentation method resulted in a lower frequency of posttreatment implant removal (one [2%] vs. six [18%]; P < .05), a lower frequency of filler injection for touch up (one [2%] vs. six [18%]; P < .05), and higher mean aesthetic scores (3.7 ± 0.5 vs. 2.2 ± 1.0; P < . 001) compared to the forehead augmentation method. There was no statistically significant difference in surgical complications between the two groups. Conclusions Integrated forehead and temporal augmentation using a 3D printing-assisted methyl methacrylate implant may be the optimal available procedure, enabling the custom fabrication of contours requested by the patient and providing a rejuvenating and balancing effect on facial appearance. Level of Evidence: 3 The contouring of the forehead affects the aesthetic appearance of the periorbital and midface regions and is important for determining the overall appearance of the face. A rounded, full, or smoothly surfaced forehead is typically considered attractive, whereas a narrow, flattened, or retruded forehead may be less desirable. The supraorbital ridge contours can markedly enhance the aesthetic features around the orbits.1 The forehead, glabella, and radix represent a critical triad in aesthetic rhinoplasty, forming the nasofrontal angle.2 For these reasons, forehead augmentation has become popular among Asians as part of a comprehensive approach to improve their facial features aesthetically.3–6 Forehead augmentation has been performed in various ways, including the placement of alloplastic implants, injection of absorbable dermal fillers, and autologous fat grafting.5–7 Silicone implants, at one time the first choice for forehead augmentation in Asia, are now rarely done because of poor results, adverse events, and the dead space between the skull and the implant that can result in clearly visible implant borders.4,6,8 In response to this problem, fat injection has become a popular alternative.2,9,10 However, this method has two serious pitfalls: less predictable survival over time and a high risk of unequal fat distribution throughout the area.7,11 Most Asian patients who request forehead augmentation also require some degree of supraorbital ridge augmentation to enhance the aesthetic appearance of the periorbital region.1,12,13 Thus, customized implants, which are delicately carved around the arcus marginalis, are essential for satisfactorily achieving the range of outcomes desired by Asian patients. Several studies have addressed forehead augmentation using alloplastic implants made from methyl methacrylate.3,4,8,14–18 The advantages of methyl methacrylate implants over other methods include their low cost, ease of implantation, and non-absorbability. In addition, their utilization is associated with minimal morbidity, good safety, and satisfactory long-term stability.3,12,16–18 Nevertheless, methyl methacrylate implantation is not a common procedure in forehead augmentation because it is invasive, with the procedure requiring a coronal incision, general anesthesia, and hospitalization. In addition, the surgeon must be skilled in craniofacial surgery to achieve a satisfactory result. Early in the practice of forehead contouring at our institution, we applied methyl methacrylate cement directly to the skull and contoured it in situ during the operation. We extended the lateral boundaries of the implants laterally only to the temporal fusion lines.8,14,15 As a result, the lateral borders were often visible posttreatment, even though we had tapered them meticulously and placed them beneath the temporal muscle (Figure 1). Temporal hollowness was occasionally accentuated posttreatment, resulting in a disharmonious appearance of the upper third of the face (Figure 1). Figure 1. View largeDownload slide Sixteen-month postoperative photograph of this 27-year-old woman who underwent forehead augmentation with an in-situ methyl methacrylate implant. The implant edges are visible at both temporal lines and the temporal concavity is poorly balanced. Figure 1. View largeDownload slide Sixteen-month postoperative photograph of this 27-year-old woman who underwent forehead augmentation with an in-situ methyl methacrylate implant. The implant edges are visible at both temporal lines and the temporal concavity is poorly balanced. To overcome these aesthetic problems, we developed the integrated forehead and temporal augmentation procedure. The purpose of the present study was to compare clinical outcomes between our new integrated method and the conventional method of forehead augmentation alone with in situ contoured methyl methacrylate implants, and with the hypothesis that the clinical outcomes of the integrated method would be superior. METHODS Between February 2000 and November 2016, a single surgeon (T.H.) performed forehead augmentation using methyl methacrylate implants for a total of 98 patients at the Ritz Cosmetic Surgery Clinic. Of these, 18 were excluded from the study because they had no 3-month follow-up or they lacked posttreatment photographs, and five more patients were excluded because they had undergone previous forehead augmentation with alloplastic implants. Thus, 75 patients were included in the present study and divided into two groups: (1) those who underwent forehead augmentation with in situ contoured and cured methyl methacrylate cement implants between February 2000 and June 2010 (n = 34; Figure 2A); and (2) those who underwent integrated forehead and temporal augmentation with prefabricated methyl methacrylate implants between July 2010 and November 2016 (n = 41; Figure 2B). We retrospectively reviewed the medical records of all the patients to obtain information about demographic characteristics, operative times, complications, and revisional surgery. Figure 2. View largeDownload slide (A) Illustration of the extent of the methyl methacrylate implants for forehead augmentation. (B) Illustration of the extent of the methyl methacrylate implant for integrated forehead and temporal augmentation. Figure 2. View largeDownload slide (A) Illustration of the extent of the methyl methacrylate implants for forehead augmentation. (B) Illustration of the extent of the methyl methacrylate implant for integrated forehead and temporal augmentation. The study was performed in accordance with the principles outlined in the Declaration of Helsinki. Written informed consent was obtained from all patients before enrollment. Patients’ information was anonymized and de-identified prior to analysis. Aesthetic Evaluation Two independent, blinded plastic surgeons (both board-certified members of the Japan Society of Plastic and Reconstructive Surgery) performed an aesthetic evaluation of each patient based on clinical preoperative and posttreatment photographs of standardized frontal, lateral, and oblique views. The reviewers were requested to pay particular attention to the implant edges and temporal hollowing and to score their overall assessments on a 4-point scale (Table 1). Table 1. Criteria for the Aesthetic Evaluation Scale Implant edges Temporal hollowing Points Excellent Invisible Unnoticeable or well-balanced 4 Good Invisible Noticeable, but normal appearance 3 Fair Visible with a firm appearance Deteriorated, but not abnormal appearance 2 Poor Clearly visible at first glance Deteriorated and abnormal appearance 1 Scale Implant edges Temporal hollowing Points Excellent Invisible Unnoticeable or well-balanced 4 Good Invisible Noticeable, but normal appearance 3 Fair Visible with a firm appearance Deteriorated, but not abnormal appearance 2 Poor Clearly visible at first glance Deteriorated and abnormal appearance 1 View Large Table 1. Criteria for the Aesthetic Evaluation Scale Implant edges Temporal hollowing Points Excellent Invisible Unnoticeable or well-balanced 4 Good Invisible Noticeable, but normal appearance 3 Fair Visible with a firm appearance Deteriorated, but not abnormal appearance 2 Poor Clearly visible at first glance Deteriorated and abnormal appearance 1 Scale Implant edges Temporal hollowing Points Excellent Invisible Unnoticeable or well-balanced 4 Good Invisible Noticeable, but normal appearance 3 Fair Visible with a firm appearance Deteriorated, but not abnormal appearance 2 Poor Clearly visible at first glance Deteriorated and abnormal appearance 1 View Large Preoperative Evaluation The characteristics of each patient’s forehead and temples were carefully observed and recorded in detail for the implant prefabrication. We made measurements of the forehead height (the distance between the supraorbital rim and frontal hairline) and forehead width (the distance between the bilateral temporal hairlines). The nasal dorsal line, including the glabella, radix, dorsum, and tip regions, was assessed to determine the need for combined rhinoplasty procedure. We also assessed the position of the eyebrows to determine the need for ancillary procedures, such as eyebrow lift or infrabrow blepharoplasty. Implant Prefabrication A computed tomography (CT) scan was routinely performed for each patient. Based on the patient’s CT findings, a life-sized model consisting of both bony skeleton and temporalis muscles was created using 3D printing (Marubeni Information Systems, Tokyo, Japan) (Figure 3). The senior author (T.H.) had this model as a template to fabricate the implant with methyl methacrylate cement (Cranioplastic Type 1–Slow Set, DePuy International, Blackpool, UK). Methyl methacrylate monomer liquid was mixed with polymer powder to form a slightly sticky paste. This was promptly applied to the model template, molded to the desired contours, and allowed to cure. After curing, the implant surface was contoured using a sharp rotating burr and filed to ensure that the desired shape was achieved and that the implant edges did not protrude onto the surrounding surface. Using a sagittal saw, the implant was divided into three separate units (a frontal forehead piece and two bilateral temporal pieces) and three holes were drilled along the margin of each piece to enable them to be connected to each other during surgery (Figure 4). The implant was sterilized using ethylene oxide gas for at least 48 h before implantation (Video 1). Video 1. Watch now at https://academic.oup.com/asj/article-lookup/doi/10.1093/asj/sjy075 Video 1. Watch now at https://academic.oup.com/asj/article-lookup/doi/10.1093/asj/sjy075 Close Figure 3. View largeDownload slide A custom model including the skeleton and temporalis muscles, made from a computed tomography scan and three-dimensional printing. The model is used for the preoperative fabrication of the custom methyl methacrylate implant for integrated forehead and temporal augmentation. Figure 3. View largeDownload slide A custom model including the skeleton and temporalis muscles, made from a computed tomography scan and three-dimensional printing. The model is used for the preoperative fabrication of the custom methyl methacrylate implant for integrated forehead and temporal augmentation. Figure 4. View largeDownload slide A newly designed implant, which covers the forehead and temples in a continuous surface extending laterally beyond the temporal hairlines. Figure 4. View largeDownload slide A newly designed implant, which covers the forehead and temples in a continuous surface extending laterally beyond the temporal hairlines. Surgical Technique The surgery was routinely performed under general anesthesia. Prior to the surgery, the posterior coronal incision line was marked from the hairline, anterosuperior to the root of the helix, and across the occiput to the contralateral helical root. The hair was washed and braided, and the entire area was infiltrated with lidocaine (0.1%) and epinephrine (1: 1,000,000). A beveled incision was made through the scalp down to the deep temporal fascia in the temporal area, and more centrally down to the periosteum. Dissection was performed laterally between the temporoparietal fascia and the deep temporal fascia, and centrally at the subgaleal layer. The central dissection was continued anteriorly, and an incision was made into the subperiosteal layer, 3–4 cm above the superior orbital rims. The central dissection continued down to the supraorbital rims. After elevating the periosteum, the supraorbital neurovascular bundles were identified and protected. The dissection was then continued down the lateral orbital rims toward the zygomatic arch. The extent of the inferior temporal dissection was individualized based on the extent of the patient’s temporal concavity. The periosteum was released at the supraorbital rim to prevent the eyebrow position from descending and to reduce tension during the closure of the scalp flap. The forehead piece of the implant was positioned centrally on the skull. After confirming that the implant fitted appropriately, it was firmly secured in place with four titanium screws. The two temporal pieces were then placed on the temporal regions and each was connected to the forehead piece with three sutures (3-0 nylon) through the holes in the implant made during fabrication. The temporal pieces were placed to overlay the deep temporal fascia without rigid fixation; this avoided palpable or visible lateral or inferior implant edges after surgery. The scalp flap was replaced, and the implant and resulting shape were carefully checked by palpation. After placing four Penrose drains, the scalp incision was closed in two layers with deep 2-0 absorbable sutures in the galea and staples to the skin, and a well-fitting forehead dressing was applied (Video 2). Video 2. Watch now at https://academic.oup.com/asj/article-lookup/doi/10.1093/asj/sjy075 Video 2. Watch now at https://academic.oup.com/asj/article-lookup/doi/10.1093/asj/sjy075 Close Statistical Analyses All data analyses were performed with SPSS for Windows, version 22.0, (IBM Japan, Tokyo, Japan). Between-group comparisons of continuous variables were performed using unpaired t-tests and the Mann–Whitney U test. Categorical data are reported as number (%) and were analyzed with Fisher’s exact test. Statistical significance was defined as P < .05. RESULTS Demographic and Surgical Characteristics Between February 2000 and November 2016, 75 patients who underwent forehead augmentation were enrolled and divided into two groups: the forehead augmentation method group, consisting of 34 patients, and the integrated forehead and temporal augmentation method group, consisting of 41 patients. Table 2 shows patient demographics and surgical characteristics of each group. The mean age for the forehead augmentation and integrated augmentation groups was 31.0 years (range, 18–62 years) and 30.5 years (range, 18–66 years), respectively. The mean follow-up period for the forehead augmentation and integrated augmentation groups was 14.8 months (range, 3–58 months) and 11.5 months (range, 3–51 months), respectively. The mean operating time for the integrated augmentation group was significantly shorter than that for the forehead augmentation group (forehead augmentation group: 184.6 minutes (range, 122–290 minutes); integrated augmentation group: 144.2 minutes (range, 104–215 minutes); P < 0.001). Table 2. Demographic and Surgical Characteristics Compared Between the Forehead Augmentation Groups Characteristic Forehead augmentation method Integrated augmentation method P No. of patients (male:female) 34 (1:33) 41 (8:33) Mean age (range), yr 31.0 (18–62) 30.5 (18–66) Mean follow-up (range), mo 14.8 (3–58) 11.5 (3–51) Mean operative time (range), min 184.6 (122–290) 144.2 (104–215) < .001* Ancillary procedure Dorsal augmentation; n (%) 16 (47.1) 22 (53.7) .646† Forehead lift; n (%) 4 (11.8) 9 (22.0) .360† Infrabrow blepharoplasty; n (%) 1 (2.9) 2 (4.9) > .999† Laser hair removal; n (%) 0 (0.0) 4 (9.8) .121† Characteristic Forehead augmentation method Integrated augmentation method P No. of patients (male:female) 34 (1:33) 41 (8:33) Mean age (range), yr 31.0 (18–62) 30.5 (18–66) Mean follow-up (range), mo 14.8 (3–58) 11.5 (3–51) Mean operative time (range), min 184.6 (122–290) 144.2 (104–215) < .001* Ancillary procedure Dorsal augmentation; n (%) 16 (47.1) 22 (53.7) .646† Forehead lift; n (%) 4 (11.8) 9 (22.0) .360† Infrabrow blepharoplasty; n (%) 1 (2.9) 2 (4.9) > .999† Laser hair removal; n (%) 0 (0.0) 4 (9.8) .121† P-value for comparison between the forehead augmentation group and the integrated augmentation group (*Mann–Whitney U test; †Fisher’s exact test). View Large Table 2. Demographic and Surgical Characteristics Compared Between the Forehead Augmentation Groups Characteristic Forehead augmentation method Integrated augmentation method P No. of patients (male:female) 34 (1:33) 41 (8:33) Mean age (range), yr 31.0 (18–62) 30.5 (18–66) Mean follow-up (range), mo 14.8 (3–58) 11.5 (3–51) Mean operative time (range), min 184.6 (122–290) 144.2 (104–215) < .001* Ancillary procedure Dorsal augmentation; n (%) 16 (47.1) 22 (53.7) .646† Forehead lift; n (%) 4 (11.8) 9 (22.0) .360† Infrabrow blepharoplasty; n (%) 1 (2.9) 2 (4.9) > .999† Laser hair removal; n (%) 0 (0.0) 4 (9.8) .121† Characteristic Forehead augmentation method Integrated augmentation method P No. of patients (male:female) 34 (1:33) 41 (8:33) Mean age (range), yr 31.0 (18–62) 30.5 (18–66) Mean follow-up (range), mo 14.8 (3–58) 11.5 (3–51) Mean operative time (range), min 184.6 (122–290) 144.2 (104–215) < .001* Ancillary procedure Dorsal augmentation; n (%) 16 (47.1) 22 (53.7) .646† Forehead lift; n (%) 4 (11.8) 9 (22.0) .360† Infrabrow blepharoplasty; n (%) 1 (2.9) 2 (4.9) > .999† Laser hair removal; n (%) 0 (0.0) 4 (9.8) .121† P-value for comparison between the forehead augmentation group and the integrated augmentation group (*Mann–Whitney U test; †Fisher’s exact test). View Large Aesthetic Evaluation There were subtle differences between the two reviewers in the results of the aesthetic evaluations (Table 3). The integrated augmentation method resulted in significantly higher mean aesthetic scores than the forehead augmentation method (forehead augmentation: 2.2 ± 1.0; integrated augmentation: 3.7 ± 0.5; P < .001). Table 3. Aesthetic Scores after Forehead Augmentation Surgery by Two Reviewers Characteristic Forehead augmentation method (n = 34) Integrated augmentation method (n = 41) P Reviewer 1 < .001*  Excellent; n (%) 4 (11.8) 33 (80.5)  Good; n (%) 5 (14.7) 6 (14.6)  Fair; n (%) 16 (47.1) 2 (4.9)  Poor; n (%) 9 (26.5) 0 (0.0)  Mean ± SD 2.1 ± 0.9 3.8 ± 0.5 < .001† Reviewer 2 < .001*  Excellent; n (%) 6 (17.6) 30 (73.2)  Good; n (%) 7 (20.6) 8 (19.5)  Fair; n (%) 12 (35.3) 3 (7.3)  Poor; n (%) 9 (26.5) 0 (0.0)  Mean ± SD 2.3 ± 1.1 3.7 ± 0.6 < .001† Average scores of two reviewers  Mean ± SD 2.2 ± 1.0 3.7 ± 0.5 < .001† Characteristic Forehead augmentation method (n = 34) Integrated augmentation method (n = 41) P Reviewer 1 < .001*  Excellent; n (%) 4 (11.8) 33 (80.5)  Good; n (%) 5 (14.7) 6 (14.6)  Fair; n (%) 16 (47.1) 2 (4.9)  Poor; n (%) 9 (26.5) 0 (0.0)  Mean ± SD 2.1 ± 0.9 3.8 ± 0.5 < .001† Reviewer 2 < .001*  Excellent; n (%) 6 (17.6) 30 (73.2)  Good; n (%) 7 (20.6) 8 (19.5)  Fair; n (%) 12 (35.3) 3 (7.3)  Poor; n (%) 9 (26.5) 0 (0.0)  Mean ± SD 2.3 ± 1.1 3.7 ± 0.6 < .001† Average scores of two reviewers  Mean ± SD 2.2 ± 1.0 3.7 ± 0.5 < .001† Aesthetic evaluation: Excellent, 4 points; Good, 3 points; Fair, 2 points; Poor, 1 point. P-value for comparison between the forehead augmentation group and the integrated augmentation group (*Mann–Whitney U test; †unpaired t test). View Large Table 3. Aesthetic Scores after Forehead Augmentation Surgery by Two Reviewers Characteristic Forehead augmentation method (n = 34) Integrated augmentation method (n = 41) P Reviewer 1 < .001*  Excellent; n (%) 4 (11.8) 33 (80.5)  Good; n (%) 5 (14.7) 6 (14.6)  Fair; n (%) 16 (47.1) 2 (4.9)  Poor; n (%) 9 (26.5) 0 (0.0)  Mean ± SD 2.1 ± 0.9 3.8 ± 0.5 < .001† Reviewer 2 < .001*  Excellent; n (%) 6 (17.6) 30 (73.2)  Good; n (%) 7 (20.6) 8 (19.5)  Fair; n (%) 12 (35.3) 3 (7.3)  Poor; n (%) 9 (26.5) 0 (0.0)  Mean ± SD 2.3 ± 1.1 3.7 ± 0.6 < .001† Average scores of two reviewers  Mean ± SD 2.2 ± 1.0 3.7 ± 0.5 < .001† Characteristic Forehead augmentation method (n = 34) Integrated augmentation method (n = 41) P Reviewer 1 < .001*  Excellent; n (%) 4 (11.8) 33 (80.5)  Good; n (%) 5 (14.7) 6 (14.6)  Fair; n (%) 16 (47.1) 2 (4.9)  Poor; n (%) 9 (26.5) 0 (0.0)  Mean ± SD 2.1 ± 0.9 3.8 ± 0.5 < .001† Reviewer 2 < .001*  Excellent; n (%) 6 (17.6) 30 (73.2)  Good; n (%) 7 (20.6) 8 (19.5)  Fair; n (%) 12 (35.3) 3 (7.3)  Poor; n (%) 9 (26.5) 0 (0.0)  Mean ± SD 2.3 ± 1.1 3.7 ± 0.6 < .001† Average scores of two reviewers  Mean ± SD 2.2 ± 1.0 3.7 ± 0.5 < .001† Aesthetic evaluation: Excellent, 4 points; Good, 3 points; Fair, 2 points; Poor, 1 point. P-value for comparison between the forehead augmentation group and the integrated augmentation group (*Mann–Whitney U test; †unpaired t test). View Large Neither reviewer scored any of the patients who received integrated augmentation with poor aesthetic results (Figure 5). A few of those patients had only fair aesthetic results, however, because of visible implant edges at the connecting portion around the temporal fusion lines. Two representative patients who were treated using the integrated method and their aesthetic scores are shown in Figures 6 and 7. Figure 5. View largeDownload slide Distribution of aesthetic evaluations for the forehead augmentation and integrated augmentation groups by two reviewers. Figure 5. View largeDownload slide Distribution of aesthetic evaluations for the forehead augmentation and integrated augmentation groups by two reviewers. Figure 6. View largeDownload slide (A, C) Preoperative and (B, D) 19-month postoperative photographs demonstrating this 38-year-old woman who underwent integrated forehead and temporal augmentation with a prefabricated methyl methacrylate implant. The implant improved the temporal hollowing, providing a rejuvenating and balancing effect to the facial appearance. The patient received an aesthetic score of 4 (Excellent) from the two reviewers. Figure 6. View largeDownload slide (A, C) Preoperative and (B, D) 19-month postoperative photographs demonstrating this 38-year-old woman who underwent integrated forehead and temporal augmentation with a prefabricated methyl methacrylate implant. The implant improved the temporal hollowing, providing a rejuvenating and balancing effect to the facial appearance. The patient received an aesthetic score of 4 (Excellent) from the two reviewers. Figure 7. View largeDownload slide (A, C) Preoperative and (B, D) 3-year postoperative photographs demonstrating this 22-year-old man who underwent integrated forehead and temporal augmentation with a prefabricated methyl methacrylate implant, dorsal augmentation, upper blepharoplasty, and an infrabrow skin excision because he desired a facial appearance like that of a Caucasian. The patient received an aesthetic score of 4 (Excellent) from the two reviewers. Figure 7. View largeDownload slide (A, C) Preoperative and (B, D) 3-year postoperative photographs demonstrating this 22-year-old man who underwent integrated forehead and temporal augmentation with a prefabricated methyl methacrylate implant, dorsal augmentation, upper blepharoplasty, and an infrabrow skin excision because he desired a facial appearance like that of a Caucasian. The patient received an aesthetic score of 4 (Excellent) from the two reviewers. Complications and Revisional Surgeries There were no major complications; however, there were some minor complications (Table 4). There were no statistically significant differences in hair loss, acne-like rash, seroma, facial nerve injury, or scalp numbness between the two groups. No significant differences in the need for implant adjustment or occipital scar revision between the two groups were observed; however, posttreatment implant removal (one [2%] vs. six [18%]; P < .05) and filler injection for touch-up (one [2%] vs. six [18%]; P < .05) were significantly less frequent after integrated augmentation than after forehead augmentation. Table 4. Complications and Revisional Surgeries After Forehead Augmentation Surgery Characteristic Forehead augmentation method (n = 34) Integrated augmentation method (n = 41) P* Complication  Acne-like rash; n (%) 2 (5.9) 2 (4.9) > .999  Facial nerve injury; n (%) 1 (2.9) 1 (2.4) > .999  Scalp numbness; n (%) 1 (2.9) 1 (2.4) > .999  Hair loss; n (%) 1 (2.9) † 0 (0.0) .453  Seroma; n (%) 0 (0.0) 1 (2.4) > .999 Revision surgery  Implant removal; n (%) 6 (17.6) 1 (2.4) .042  Filler injection; n (%) 6 (17.6) 1 (2.4) .042  Implant adjustment; n (%) 4 (11.8) 2 (4.9) .401  Occipital scar revision; n (%) 2 (5.9) 1 (2.4) .587 Characteristic Forehead augmentation method (n = 34) Integrated augmentation method (n = 41) P* Complication  Acne-like rash; n (%) 2 (5.9) 2 (4.9) > .999  Facial nerve injury; n (%) 1 (2.9) 1 (2.4) > .999  Scalp numbness; n (%) 1 (2.9) 1 (2.4) > .999  Hair loss; n (%) 1 (2.9) † 0 (0.0) .453  Seroma; n (%) 0 (0.0) 1 (2.4) > .999 Revision surgery  Implant removal; n (%) 6 (17.6) 1 (2.4) .042  Filler injection; n (%) 6 (17.6) 1 (2.4) .042  Implant adjustment; n (%) 4 (11.8) 2 (4.9) .401  Occipital scar revision; n (%) 2 (5.9) 1 (2.4) .587 *P-value for comparison between the forehead augmentation group and the integrated augmentation group (Fisher’s exact test). †Two areas of hair loss (diameter, approximately 1–2 cm each), resolved after implant removal. View Large Table 4. Complications and Revisional Surgeries After Forehead Augmentation Surgery Characteristic Forehead augmentation method (n = 34) Integrated augmentation method (n = 41) P* Complication  Acne-like rash; n (%) 2 (5.9) 2 (4.9) > .999  Facial nerve injury; n (%) 1 (2.9) 1 (2.4) > .999  Scalp numbness; n (%) 1 (2.9) 1 (2.4) > .999  Hair loss; n (%) 1 (2.9) † 0 (0.0) .453  Seroma; n (%) 0 (0.0) 1 (2.4) > .999 Revision surgery  Implant removal; n (%) 6 (17.6) 1 (2.4) .042  Filler injection; n (%) 6 (17.6) 1 (2.4) .042  Implant adjustment; n (%) 4 (11.8) 2 (4.9) .401  Occipital scar revision; n (%) 2 (5.9) 1 (2.4) .587 Characteristic Forehead augmentation method (n = 34) Integrated augmentation method (n = 41) P* Complication  Acne-like rash; n (%) 2 (5.9) 2 (4.9) > .999  Facial nerve injury; n (%) 1 (2.9) 1 (2.4) > .999  Scalp numbness; n (%) 1 (2.9) 1 (2.4) > .999  Hair loss; n (%) 1 (2.9) † 0 (0.0) .453  Seroma; n (%) 0 (0.0) 1 (2.4) > .999 Revision surgery  Implant removal; n (%) 6 (17.6) 1 (2.4) .042  Filler injection; n (%) 6 (17.6) 1 (2.4) .042  Implant adjustment; n (%) 4 (11.8) 2 (4.9) .401  Occipital scar revision; n (%) 2 (5.9) 1 (2.4) .587 *P-value for comparison between the forehead augmentation group and the integrated augmentation group (Fisher’s exact test). †Two areas of hair loss (diameter, approximately 1–2 cm each), resolved after implant removal. View Large For all patients combined, there were four patients who developed an acne-like rash on the forehead that subsided spontaneously within 6 months; two patients who had facial nerve palsy that resolved within 6 months; and two patients who developed scalp numbness and paresthesia (resolved in one patient after 8 months; persistent in one patient for >1 year). Three patients received scar revision because of wide scarring or alopecia along the incision line. One patient had a seroma that subsided after therapeutic syringe aspiration was performed twice. One patient had hair loss in two areas (each, 1–2 cm) behind the anterior hairline at 2 years after surgery, each the size of a coin, that resolved after implant removal at the patient’s request. The exact cause of this symptom remains unknown. DISCUSSION Our results support the hypothesis that clinical outcomes of our new integrated procedure would be superior to those of forehead augmentation with in situ contoured methyl methacrylate implants. According to the aesthetic evaluations by two reviewers, visible implant edges and deteriorated temporal hollowing, which were frequently associated with the forehead augmentation method, were avoided with the integrated augmentation method. Methyl Methacrylate Materials The present study indicates that methyl methacrylate is a unique material, enabling the custom fabrication of contours requested by the patient and facilitating the optimal augmentation of the forehead and temple.1,8,12 The greatest advantage of using methyl methacrylate for aesthetic reconstructive surgery is its morphological plasticity, which enables the fabrication of custom contours in accordance with the patients’ requests. When methyl methacrylate is applied in situ, the adjacent tissue, especially the temporal muscle, may be damaged by the exothermic reaction during polymerization; however, this risk can be avoided by prefabricating the implant.3,19–22 In addition, the acrylic resin is a foreign body that may cause an allergic or autoimmune reaction, infection, extrusion, extravasation, tissue erosion, hematoma, or seroma.8,14,15,23–25 In the present study, we observed no major adverse complications. We also have not had a single case of infection or wound dehiscence. The occipital coronal approach, in which the incision did not overlap the placed implant, may contribute to the prevention of infection or wound dehiscence. The long-term potential complications involve implant exposure, bone erosion, and implant fragmentation; however, we have observed no cases of such complications during the follow-up period in our study. Although we have demonstrated early success with our method, longer-term follow-up is still required to fully evaluate the safety and implant retention rate. This is an important consideration in outcome studies, as aesthetic problems with foreign bodies may arise over time, as in other operations using alloplastic implants. Newly Designed Integrated Forehead and Temporal Implant During the early days of our practice of forehead contouring, the shape and range of implants were similar to those of implants in the methods previously described;8,12–15 the area targeted for forehead augmentation with an in situ implant was restricted to the area between the temporal lines (Figure 2A).3–6,8,12,13,15 The edges of the implant were carefully molded around the bony skeleton, and the lateral edges were placed beneath the temporalis muscles, which were repositioned and secured to the implant.12,13,26 Despite these adjustments, lateral edges of the implant were frequently visible after surgery.26 The overlying soft-tissue envelope sometimes became thinner over time, causing the implant edges to become more conspicuous (Figure 8).12 In addition, forehead augmentation occasionally accentuated temporal hollowing, resulting in disharmonious features in the upper third of the face (Figure 1).26 Figure 8. View largeDownload slide (A) Preoperative (B) 1-year postoperative and (C) 10-year postoperative photographs demonstrating this 24-year-old woman who underwent forehead augmentation with an in-situ methyl methacrylate implant. Her forehead tissue became progressively thinner, causing the implant edges to become more conspicuous. Figure 8. View largeDownload slide (A) Preoperative (B) 1-year postoperative and (C) 10-year postoperative photographs demonstrating this 24-year-old woman who underwent forehead augmentation with an in-situ methyl methacrylate implant. Her forehead tissue became progressively thinner, causing the implant edges to become more conspicuous. The key issue was that the site targeted for established forehead augmentation using methyl methacrylate as well as silicone implants was restricted to the area between the temporal lines. Our proposal in this study is that combined temporal augmentation should always be taken into consideration for forehead augmentation. Temporal augmentation is commonly conducted by placing a prosthetic implant into the temporal fossa beneath the temporal muscle.27 If the forehead and temporal augmentations are independently performed, the boundary between the forehead and temple can become clearer without continuity at the temporal line. It is therefore of critical importance to contour the forehead and temple with a continuous plane to achieve a well-balanced and smooth-surfaced forehead. Thus, we developed an implant that covers the forehead and temples in a continuous surface extending laterally into the temporal hairlines (Figure 4). Tips for Implant Prefabrication Prefabricating the implant is the most important step in achieving aesthetically pleasing results. We first had to identify the ideal skull shape in the forehead region. Based on our observation of hundreds of subjectively beautiful Asian models and actresses, the ideal profile of the forehead was determined to be relatively vertical in the lower two-thirds, with the upper third declined toward the anterior hairline. The ideal implant was also fabricated to have a smooth surface without any irregularities, be natural-looking (avoiding over-prominence), and be borderless between the forehead and temporal region. The supraorbital ridge and glabella region should be meticulously adjusted relative to the radix to create a dorsal aesthetic line. Caution should be taken to avoid an overaggressive forehead and maintain the racial characteristics of Asian beauty: the implant should be less than 5 mm at its maximum thickness. The principal reason for implant removal in the study was an undesirable over-corrected forehead feature; five of the seven patients requested implant removal due to over-correction. Surgeons must consider such characteristics when fabricating custom-made implants. Even when all factors are considered, fabrication of the abovementioned ideal implant requires considerable expertise and experience. The Placement Layer of the Temporal Implant The placement layer of the temporal implant remains controversial. When we began performing this technique in July 2010, posttreatment thinning of the overlying soft tissue coverage was our primary concern, as subcutaneous temporal implants can expand and stretch the overlying skin. Such thinning of the skin can have negative consequences, such as allowing the patient to easily feel the implant. We considered two main factors to underlie posttreatment thinning of the overlying soft tissue coverage. First, the underlying structure is strongly implicated. In our method, the completed one-unit implant is divided into three units; these units are then connected with nylon sutures during surgery and held in a stable position by the surrounding fibrotic capsule. At the same time, the temporal pieces are allowed vertical mobility on the temporalis muscle, which may help prevent progressive thinning of the soft tissue coverage because the underlying temporalis muscles work as buffer material under the implant. Second, the thickness of the temporal pieces is also associated with the thinning of the skin. Temporal pieces were routinely fabricated to be less than 3 mm in thickness in our study, regardless of the severity of patients’ temporal hollowing. The main role of the temporal pieces is to prevent the visible edge of the forehead implant, and not to correct temporal hollowing. Despite concerns of thinning skin over time due to implant placement over the temporalis muscle, no such cases were observed during the follow-up period. However, we carefully educate patients on the importance of returning to our clinic if they have an eventful posttreatment course. Ancillary Procedures Integrated forehead and temporal augmentation required some ancillary procedures to achieve aesthetically harmonious facial features (Table 2). The nasal dorsum can be consistently affected by altering the contour and dimensions of the forehead/glabella/radix complex. A cranial radix position provides a longer nasal dorsum, whereas a caudal position delineates a shorter nasal dorsum. A deep radix reduces the nasofrontal angle, whereas a high radix enlarges the nasofrontal angle. For this reason, we routinely performed dorsal augmentation to optimize aesthetic balance between the nose and forehead for patients who requested glabella and radix augmentation. The vertical height of the forehead was an important factor in the overall aesthetic of the forehead. In our opinion, the ideal distance between the supraorbital rim and the frontal hairline was 65–70 mm. We, therefore, recommended a forehead lift to raise the anterior hairline for patients whose vertical height of the forehead was <60 mm. Forehead lift was performed simultaneous to augmentation, using a method similar to that for endoscopic brow lift. The frontal hairline was pulled posteriorly and secured with fixation screws at the hairline. A desirable frontal hairline position and shape could also be achieved using laser hair removal. The position of the eyebrows was also important, especially for patients who requested supraorbital ridge augmentation. We performed eyebrow lifts for patients who had a low eyebrow position, with scoring of the supraorbital periosteum and internal screw fixation. For the patients with a high eyebrow position, we performed infrabrow blepharoplasty. Study Limitations There are inherent limitations associated with this retrospective study, including the relatively small sample size and the relatively short follow-up period. In addition, the amount of methyl methacrylate cement used for each patient may have affected the complication rates; however, we could not evaluate this because we added and shaved off cement repeatedly while fabricating the implant. As patient-reported outcomes are becoming popular considerations in the field of plastic surgery, an assessment of patient satisfaction after surgery is necessary and presently underway. Another limitation was the having photographs to score aesthetic outcomes; this process may require validation against clinical face- to-face scoring, even for experienced plastic surgeons. Based on our results and experiences, we advocate that integrated forehead and temporal augmentation be considered an excellent alternative to forehead augmentation. To our knowledge, this is the first study to examine combined temporal and forehead augmentation using alloplastic implants. A 3D printing-assisted model consisting of both a bony skeleton and temporalis muscles provided innovative insight to forehead contouring surgery. Our newly designed implant is unique in that the forehead and temporal pieces yield a continuous plane despite being placed as separate layers; the vertical mobility of temporal pieces may help prevent progressive thinning of the soft tissue coverage. Further study is required to examine the effectiveness of this procedure with a higher number of patients and a longer follow-up period. CONCLUSIONS The biggest advantage of using methyl methacrylate for forehead augmentation procedure is its morphological plasticity, which enables the fabrication of custom contours around both forehead/glabella/supraorbital and temporal region in accordance with the patients’ requests. The results of our study suggest that integrated forehead and temporal augmentation with prefabricated methyl methacrylate may be the optimal available procedure for forehead augmentation, resulting in a rejuvenating and balancing effect on facial appearance. Supplementary Material This article contains supplementary material located online at www.aestheticsurgeryjournal.com. Acknowledgments The authors thank Ms Sakiko Katsumata for creating the artwork for this article. The authors also thank Dr Yuzo Komuro and Ms Mizuho Kamisawa for the invaluable contributions to this article. Disclosures The authors declared no potential conflicts of interest with respect to the research, authorship, and publication of this article. Funding The authors received no financial support for the research, authorship, and publication of this article. REFERENCES 1. Whitaker LA , Morales L Jr , Farkas LG . Aesthetic surgery of the supraorbital ridge and forehead structures . Plast Reconstr Surg . 1986 ; 78 ( 1 ): 23 - 32 . Google Scholar Crossref Search ADS PubMed 2. Kornstein AN , Nikfarjam JS . Fat grafting to the forehead/glabella/radix complex and pyriform aperture: aesthetic and anti-aging implications . Plast Reconstr Surg Glob Open . 2015 ; 3 ( 8 ): e500 . Google Scholar Crossref Search ADS PubMed 3. Song YT . Using methyl methacrylate in forehead contouring for aesthetic purposes . J Craniofac Surg . 2013 ; 24 ( 5 ): 1622 - 1627 . Google Scholar Crossref Search ADS PubMed 4. Park DK , Song I , Lee JH , You YJ . Forehead augmentation with a methyl methacrylate onlay implant using an injection-molding technique . Arch Plast Surg . 2013 ; 40 ( 5 ): 597 - 602 . Google Scholar Crossref Search ADS PubMed 5. Lee DW , Kim JY , Lew DH . Use of rapidly hardening hydroxyapatite cement for facial contouring surgery . J Craniofac Surg . 2010 ; 21 ( 4 ): 1084 - 1088 . Google Scholar Crossref Search ADS PubMed 6. Chao JW , Lee JC , Chang MM , Kwan E . Alloplastic augmentation of the Asian face: a review of 215 patients . Aesthet Surg J . 2016 ; 36 ( 8 ): 861 - 868 . Google Scholar Crossref Search ADS PubMed 7. Coleman SR . Structural fat grafting: more than a permanent filler . Plast Reconstr Surg . 2006 ; 118 ( 3 Suppl ): 108S - 120S . Google Scholar Crossref Search ADS PubMed 8. Ousterhout DK , Zlotolow IM . Aesthetic improvement of the forehead utilizing methylmethacrylate onlay implants . Aesthetic Plast Surg . 1990 ; 14 ( 4 ): 281 - 285 . Google Scholar Crossref Search ADS PubMed 9. Shue S , Kurlander DE , Guyuron B . Fat injection: A systematic review of injection volumes by facial subunit . Aesthetic Plast Surg . 2017 . doi: 10.1007/s00266-017-0936-6 . [Epub ahead of print] 10. Isik S , Sahin I . Contour restoration of the forehead by lipofilling: our experience . Aesthetic Plast Surg . 2012 ; 36 ( 4 ): 761 - 766 . Google Scholar Crossref Search ADS PubMed 11. Fontdevila J , Serra-Renom JM , Raigosa M , et al. Assessing the long-term viability of facial fat grafts: an objective measure using computed tomography . Aesthet Surg J . 2008 ; 28 ( 4 ): 380 - 386 . Google Scholar Crossref Search ADS PubMed 12. Ousterhout DK . Prosthetic forehead augmentation . In: Ousterhout DK , ed. Aesthetic Contouring of the Craniofacial Skeleton . 1st ed . Boston : Little Brown & Co ; 1991 : 199 - 219 . 13. Habal MB . Aesthetic contouring of the forehead utilizing contour template and bone grafts . In: Ousterhout DK , ed. Aesthetic Contouring of the Craniofacial Skeleton . 1st ed . Boston : Little Brown & Co ; 1991 : 229 - 242 . 14. Gonzalez Ulloa M , Stevens E . Implants in the face; a review of our experience in the subcutaneous use of methylmethacrylate . Plast Reconstr Surg . 1964 ; 33 : 532 - 542 . Google Scholar PubMed 15. Ousterhout DK , Baker S , Zlotolow I . Methylmethacrylate onlay implants in the treatment of forehead deformities secondary to craniosynostosis . J Maxillofac Surg . 1980 ; 8 ( 3 ): 228 - 233 . Google Scholar Crossref Search ADS PubMed 16. Olson NR , Newman MH . Acrylic frontal cranioplasty . Arch Otolaryngol . 1969 ; 89 ( 5 ): 774 - 777 . Google Scholar Crossref Search ADS PubMed 17. Argenta LC , Newman MH . The use of methyl methacrylate cranioplasty in forehead reconstruction . Eur J Plast Surg . 1986 ; 9 ( 3 ): 94 - 99 . Google Scholar Crossref Search ADS 18. Schultz RC . Restoration of frontal contour with methyl methacrylate . Ann Plast Surg . 1979 ; 3 ( 4 ): 295 - 303 . Google Scholar Crossref Search ADS PubMed 19. Binder WJ , Kaye A . Reconstruction of posttraumatic and congenital facial deformities with three-dimensional computer-assisted custom-designed implants . Plast Reconstr Surg . 1994 ; 94 ( 6 ): 775 - 785 ; discussion 786. Google Scholar Crossref Search ADS PubMed 20. Eppley BL , Kilgo M , Coleman JJ 3rd . Cranial reconstruction with computer-generated hard-tissue replacement patient-matched implants: indications, surgical technique, and long-term follow-up . Plast Reconstr Surg . 2002 ; 109 ( 3 ): 864 - 871 . Google Scholar Crossref Search ADS PubMed 21. Toth BA , Ellis DS , Stewart WB . Computer-designed prostheses for orbitocranial reconstruction . Plast Reconstr Surg . 1988 ; 81 ( 3 ): 315 - 324 . Google Scholar Crossref Search ADS PubMed 22. Stelnicki EJ , Ousterhout DK . Prevention of thermal tissue injury induced by the application of polymethylmethacrylate to the calvarium . J Craniofac Surg . 1996 ; 7 ( 3 ): 192 - 195 . Google Scholar Crossref Search ADS PubMed 23. Gautschi OP , Schlett CL , Fournier JY , Cadosch D . Laboratory confirmed polymethyl-methacrylate (Palacos)-hypersensitivity after cranioplasty . Clin Neurol Neurosurg . 2010 ; 112 ( 10 ): 915 - 916 . Google Scholar Crossref Search ADS PubMed 24. Goon AT , Bruze M , Zimerson E , Goh CL , Soo-Quee Koh D , Isaksson M . Screening for acrylate/methacrylate allergy in the baseline series: our experience in Sweden and Singapore . Contact Dermatitis . 2008 ; 59 ( 5 ): 307 - 313 . Google Scholar Crossref Search ADS PubMed 25. Thomas P , Schuh A , Eben R , Thomsen M . Allergy to bone cement components . Orthopade . 2008 ; 37 ( 2 ): 117 - 120 . Google Scholar Crossref Search ADS PubMed 26. Gordon CR , Yaremchuk MJ . Temporal augmentation with methyl methacrylate . Aesthet Surg J . 2011 ; 31 ( 7 ): 827 - 833 . Google Scholar Crossref Search ADS PubMed 27. Yaremchuk MJ . Facial skeletal reconstruction using porous polyethylene implants . Plast Reconstr Surg . 2003 ; 111 ( 6 ): 1818 - 1827 . Google Scholar Crossref Search ADS PubMed © 2018 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model) http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Aesthetic Surgery Journal Oxford University Press

Integrated Forehead and Temporal Augmentation Using 3D Printing-Assisted Methyl Methacrylate Implants

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Oxford University Press
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© 2018 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com
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Abstract

Abstract Background Achieving aesthetic results with forehead augmentation procedures remains challenging. We have developed a method of integrated forehead and temporal augmentation using a three-dimensional (3D) printing-assisted methyl methacrylate implant. Objectives The study objective was to assess the importance of combined temporal augmentation when performing forehead augmentation. Methods We identified 34 patients (from 2000 to 2010) who underwent forehead augmentation with a methyl methacrylate implant contoured in situ during surgery and 41 patients (from 2010 to 2016) who underwent integrated forehead and temporal augmentation with a prefabricated methyl methacrylate implant. We conducted a retrospective chart review of patient data including operation time, complications, and instances of revision surgery. Two blinded plastic surgeons scored the aesthetic results of the operations on a 4-point scale (1, poor, to 4, excellent) based on preoperative and posttreatment photographs. Results The integrated augmentation method resulted in a lower frequency of posttreatment implant removal (one [2%] vs. six [18%]; P < .05), a lower frequency of filler injection for touch up (one [2%] vs. six [18%]; P < .05), and higher mean aesthetic scores (3.7 ± 0.5 vs. 2.2 ± 1.0; P < . 001) compared to the forehead augmentation method. There was no statistically significant difference in surgical complications between the two groups. Conclusions Integrated forehead and temporal augmentation using a 3D printing-assisted methyl methacrylate implant may be the optimal available procedure, enabling the custom fabrication of contours requested by the patient and providing a rejuvenating and balancing effect on facial appearance. Level of Evidence: 3 The contouring of the forehead affects the aesthetic appearance of the periorbital and midface regions and is important for determining the overall appearance of the face. A rounded, full, or smoothly surfaced forehead is typically considered attractive, whereas a narrow, flattened, or retruded forehead may be less desirable. The supraorbital ridge contours can markedly enhance the aesthetic features around the orbits.1 The forehead, glabella, and radix represent a critical triad in aesthetic rhinoplasty, forming the nasofrontal angle.2 For these reasons, forehead augmentation has become popular among Asians as part of a comprehensive approach to improve their facial features aesthetically.3–6 Forehead augmentation has been performed in various ways, including the placement of alloplastic implants, injection of absorbable dermal fillers, and autologous fat grafting.5–7 Silicone implants, at one time the first choice for forehead augmentation in Asia, are now rarely done because of poor results, adverse events, and the dead space between the skull and the implant that can result in clearly visible implant borders.4,6,8 In response to this problem, fat injection has become a popular alternative.2,9,10 However, this method has two serious pitfalls: less predictable survival over time and a high risk of unequal fat distribution throughout the area.7,11 Most Asian patients who request forehead augmentation also require some degree of supraorbital ridge augmentation to enhance the aesthetic appearance of the periorbital region.1,12,13 Thus, customized implants, which are delicately carved around the arcus marginalis, are essential for satisfactorily achieving the range of outcomes desired by Asian patients. Several studies have addressed forehead augmentation using alloplastic implants made from methyl methacrylate.3,4,8,14–18 The advantages of methyl methacrylate implants over other methods include their low cost, ease of implantation, and non-absorbability. In addition, their utilization is associated with minimal morbidity, good safety, and satisfactory long-term stability.3,12,16–18 Nevertheless, methyl methacrylate implantation is not a common procedure in forehead augmentation because it is invasive, with the procedure requiring a coronal incision, general anesthesia, and hospitalization. In addition, the surgeon must be skilled in craniofacial surgery to achieve a satisfactory result. Early in the practice of forehead contouring at our institution, we applied methyl methacrylate cement directly to the skull and contoured it in situ during the operation. We extended the lateral boundaries of the implants laterally only to the temporal fusion lines.8,14,15 As a result, the lateral borders were often visible posttreatment, even though we had tapered them meticulously and placed them beneath the temporal muscle (Figure 1). Temporal hollowness was occasionally accentuated posttreatment, resulting in a disharmonious appearance of the upper third of the face (Figure 1). Figure 1. View largeDownload slide Sixteen-month postoperative photograph of this 27-year-old woman who underwent forehead augmentation with an in-situ methyl methacrylate implant. The implant edges are visible at both temporal lines and the temporal concavity is poorly balanced. Figure 1. View largeDownload slide Sixteen-month postoperative photograph of this 27-year-old woman who underwent forehead augmentation with an in-situ methyl methacrylate implant. The implant edges are visible at both temporal lines and the temporal concavity is poorly balanced. To overcome these aesthetic problems, we developed the integrated forehead and temporal augmentation procedure. The purpose of the present study was to compare clinical outcomes between our new integrated method and the conventional method of forehead augmentation alone with in situ contoured methyl methacrylate implants, and with the hypothesis that the clinical outcomes of the integrated method would be superior. METHODS Between February 2000 and November 2016, a single surgeon (T.H.) performed forehead augmentation using methyl methacrylate implants for a total of 98 patients at the Ritz Cosmetic Surgery Clinic. Of these, 18 were excluded from the study because they had no 3-month follow-up or they lacked posttreatment photographs, and five more patients were excluded because they had undergone previous forehead augmentation with alloplastic implants. Thus, 75 patients were included in the present study and divided into two groups: (1) those who underwent forehead augmentation with in situ contoured and cured methyl methacrylate cement implants between February 2000 and June 2010 (n = 34; Figure 2A); and (2) those who underwent integrated forehead and temporal augmentation with prefabricated methyl methacrylate implants between July 2010 and November 2016 (n = 41; Figure 2B). We retrospectively reviewed the medical records of all the patients to obtain information about demographic characteristics, operative times, complications, and revisional surgery. Figure 2. View largeDownload slide (A) Illustration of the extent of the methyl methacrylate implants for forehead augmentation. (B) Illustration of the extent of the methyl methacrylate implant for integrated forehead and temporal augmentation. Figure 2. View largeDownload slide (A) Illustration of the extent of the methyl methacrylate implants for forehead augmentation. (B) Illustration of the extent of the methyl methacrylate implant for integrated forehead and temporal augmentation. The study was performed in accordance with the principles outlined in the Declaration of Helsinki. Written informed consent was obtained from all patients before enrollment. Patients’ information was anonymized and de-identified prior to analysis. Aesthetic Evaluation Two independent, blinded plastic surgeons (both board-certified members of the Japan Society of Plastic and Reconstructive Surgery) performed an aesthetic evaluation of each patient based on clinical preoperative and posttreatment photographs of standardized frontal, lateral, and oblique views. The reviewers were requested to pay particular attention to the implant edges and temporal hollowing and to score their overall assessments on a 4-point scale (Table 1). Table 1. Criteria for the Aesthetic Evaluation Scale Implant edges Temporal hollowing Points Excellent Invisible Unnoticeable or well-balanced 4 Good Invisible Noticeable, but normal appearance 3 Fair Visible with a firm appearance Deteriorated, but not abnormal appearance 2 Poor Clearly visible at first glance Deteriorated and abnormal appearance 1 Scale Implant edges Temporal hollowing Points Excellent Invisible Unnoticeable or well-balanced 4 Good Invisible Noticeable, but normal appearance 3 Fair Visible with a firm appearance Deteriorated, but not abnormal appearance 2 Poor Clearly visible at first glance Deteriorated and abnormal appearance 1 View Large Table 1. Criteria for the Aesthetic Evaluation Scale Implant edges Temporal hollowing Points Excellent Invisible Unnoticeable or well-balanced 4 Good Invisible Noticeable, but normal appearance 3 Fair Visible with a firm appearance Deteriorated, but not abnormal appearance 2 Poor Clearly visible at first glance Deteriorated and abnormal appearance 1 Scale Implant edges Temporal hollowing Points Excellent Invisible Unnoticeable or well-balanced 4 Good Invisible Noticeable, but normal appearance 3 Fair Visible with a firm appearance Deteriorated, but not abnormal appearance 2 Poor Clearly visible at first glance Deteriorated and abnormal appearance 1 View Large Preoperative Evaluation The characteristics of each patient’s forehead and temples were carefully observed and recorded in detail for the implant prefabrication. We made measurements of the forehead height (the distance between the supraorbital rim and frontal hairline) and forehead width (the distance between the bilateral temporal hairlines). The nasal dorsal line, including the glabella, radix, dorsum, and tip regions, was assessed to determine the need for combined rhinoplasty procedure. We also assessed the position of the eyebrows to determine the need for ancillary procedures, such as eyebrow lift or infrabrow blepharoplasty. Implant Prefabrication A computed tomography (CT) scan was routinely performed for each patient. Based on the patient’s CT findings, a life-sized model consisting of both bony skeleton and temporalis muscles was created using 3D printing (Marubeni Information Systems, Tokyo, Japan) (Figure 3). The senior author (T.H.) had this model as a template to fabricate the implant with methyl methacrylate cement (Cranioplastic Type 1–Slow Set, DePuy International, Blackpool, UK). Methyl methacrylate monomer liquid was mixed with polymer powder to form a slightly sticky paste. This was promptly applied to the model template, molded to the desired contours, and allowed to cure. After curing, the implant surface was contoured using a sharp rotating burr and filed to ensure that the desired shape was achieved and that the implant edges did not protrude onto the surrounding surface. Using a sagittal saw, the implant was divided into three separate units (a frontal forehead piece and two bilateral temporal pieces) and three holes were drilled along the margin of each piece to enable them to be connected to each other during surgery (Figure 4). The implant was sterilized using ethylene oxide gas for at least 48 h before implantation (Video 1). Video 1. Watch now at https://academic.oup.com/asj/article-lookup/doi/10.1093/asj/sjy075 Video 1. Watch now at https://academic.oup.com/asj/article-lookup/doi/10.1093/asj/sjy075 Close Figure 3. View largeDownload slide A custom model including the skeleton and temporalis muscles, made from a computed tomography scan and three-dimensional printing. The model is used for the preoperative fabrication of the custom methyl methacrylate implant for integrated forehead and temporal augmentation. Figure 3. View largeDownload slide A custom model including the skeleton and temporalis muscles, made from a computed tomography scan and three-dimensional printing. The model is used for the preoperative fabrication of the custom methyl methacrylate implant for integrated forehead and temporal augmentation. Figure 4. View largeDownload slide A newly designed implant, which covers the forehead and temples in a continuous surface extending laterally beyond the temporal hairlines. Figure 4. View largeDownload slide A newly designed implant, which covers the forehead and temples in a continuous surface extending laterally beyond the temporal hairlines. Surgical Technique The surgery was routinely performed under general anesthesia. Prior to the surgery, the posterior coronal incision line was marked from the hairline, anterosuperior to the root of the helix, and across the occiput to the contralateral helical root. The hair was washed and braided, and the entire area was infiltrated with lidocaine (0.1%) and epinephrine (1: 1,000,000). A beveled incision was made through the scalp down to the deep temporal fascia in the temporal area, and more centrally down to the periosteum. Dissection was performed laterally between the temporoparietal fascia and the deep temporal fascia, and centrally at the subgaleal layer. The central dissection was continued anteriorly, and an incision was made into the subperiosteal layer, 3–4 cm above the superior orbital rims. The central dissection continued down to the supraorbital rims. After elevating the periosteum, the supraorbital neurovascular bundles were identified and protected. The dissection was then continued down the lateral orbital rims toward the zygomatic arch. The extent of the inferior temporal dissection was individualized based on the extent of the patient’s temporal concavity. The periosteum was released at the supraorbital rim to prevent the eyebrow position from descending and to reduce tension during the closure of the scalp flap. The forehead piece of the implant was positioned centrally on the skull. After confirming that the implant fitted appropriately, it was firmly secured in place with four titanium screws. The two temporal pieces were then placed on the temporal regions and each was connected to the forehead piece with three sutures (3-0 nylon) through the holes in the implant made during fabrication. The temporal pieces were placed to overlay the deep temporal fascia without rigid fixation; this avoided palpable or visible lateral or inferior implant edges after surgery. The scalp flap was replaced, and the implant and resulting shape were carefully checked by palpation. After placing four Penrose drains, the scalp incision was closed in two layers with deep 2-0 absorbable sutures in the galea and staples to the skin, and a well-fitting forehead dressing was applied (Video 2). Video 2. Watch now at https://academic.oup.com/asj/article-lookup/doi/10.1093/asj/sjy075 Video 2. Watch now at https://academic.oup.com/asj/article-lookup/doi/10.1093/asj/sjy075 Close Statistical Analyses All data analyses were performed with SPSS for Windows, version 22.0, (IBM Japan, Tokyo, Japan). Between-group comparisons of continuous variables were performed using unpaired t-tests and the Mann–Whitney U test. Categorical data are reported as number (%) and were analyzed with Fisher’s exact test. Statistical significance was defined as P < .05. RESULTS Demographic and Surgical Characteristics Between February 2000 and November 2016, 75 patients who underwent forehead augmentation were enrolled and divided into two groups: the forehead augmentation method group, consisting of 34 patients, and the integrated forehead and temporal augmentation method group, consisting of 41 patients. Table 2 shows patient demographics and surgical characteristics of each group. The mean age for the forehead augmentation and integrated augmentation groups was 31.0 years (range, 18–62 years) and 30.5 years (range, 18–66 years), respectively. The mean follow-up period for the forehead augmentation and integrated augmentation groups was 14.8 months (range, 3–58 months) and 11.5 months (range, 3–51 months), respectively. The mean operating time for the integrated augmentation group was significantly shorter than that for the forehead augmentation group (forehead augmentation group: 184.6 minutes (range, 122–290 minutes); integrated augmentation group: 144.2 minutes (range, 104–215 minutes); P < 0.001). Table 2. Demographic and Surgical Characteristics Compared Between the Forehead Augmentation Groups Characteristic Forehead augmentation method Integrated augmentation method P No. of patients (male:female) 34 (1:33) 41 (8:33) Mean age (range), yr 31.0 (18–62) 30.5 (18–66) Mean follow-up (range), mo 14.8 (3–58) 11.5 (3–51) Mean operative time (range), min 184.6 (122–290) 144.2 (104–215) < .001* Ancillary procedure Dorsal augmentation; n (%) 16 (47.1) 22 (53.7) .646† Forehead lift; n (%) 4 (11.8) 9 (22.0) .360† Infrabrow blepharoplasty; n (%) 1 (2.9) 2 (4.9) > .999† Laser hair removal; n (%) 0 (0.0) 4 (9.8) .121† Characteristic Forehead augmentation method Integrated augmentation method P No. of patients (male:female) 34 (1:33) 41 (8:33) Mean age (range), yr 31.0 (18–62) 30.5 (18–66) Mean follow-up (range), mo 14.8 (3–58) 11.5 (3–51) Mean operative time (range), min 184.6 (122–290) 144.2 (104–215) < .001* Ancillary procedure Dorsal augmentation; n (%) 16 (47.1) 22 (53.7) .646† Forehead lift; n (%) 4 (11.8) 9 (22.0) .360† Infrabrow blepharoplasty; n (%) 1 (2.9) 2 (4.9) > .999† Laser hair removal; n (%) 0 (0.0) 4 (9.8) .121† P-value for comparison between the forehead augmentation group and the integrated augmentation group (*Mann–Whitney U test; †Fisher’s exact test). View Large Table 2. Demographic and Surgical Characteristics Compared Between the Forehead Augmentation Groups Characteristic Forehead augmentation method Integrated augmentation method P No. of patients (male:female) 34 (1:33) 41 (8:33) Mean age (range), yr 31.0 (18–62) 30.5 (18–66) Mean follow-up (range), mo 14.8 (3–58) 11.5 (3–51) Mean operative time (range), min 184.6 (122–290) 144.2 (104–215) < .001* Ancillary procedure Dorsal augmentation; n (%) 16 (47.1) 22 (53.7) .646† Forehead lift; n (%) 4 (11.8) 9 (22.0) .360† Infrabrow blepharoplasty; n (%) 1 (2.9) 2 (4.9) > .999† Laser hair removal; n (%) 0 (0.0) 4 (9.8) .121† Characteristic Forehead augmentation method Integrated augmentation method P No. of patients (male:female) 34 (1:33) 41 (8:33) Mean age (range), yr 31.0 (18–62) 30.5 (18–66) Mean follow-up (range), mo 14.8 (3–58) 11.5 (3–51) Mean operative time (range), min 184.6 (122–290) 144.2 (104–215) < .001* Ancillary procedure Dorsal augmentation; n (%) 16 (47.1) 22 (53.7) .646† Forehead lift; n (%) 4 (11.8) 9 (22.0) .360† Infrabrow blepharoplasty; n (%) 1 (2.9) 2 (4.9) > .999† Laser hair removal; n (%) 0 (0.0) 4 (9.8) .121† P-value for comparison between the forehead augmentation group and the integrated augmentation group (*Mann–Whitney U test; †Fisher’s exact test). View Large Aesthetic Evaluation There were subtle differences between the two reviewers in the results of the aesthetic evaluations (Table 3). The integrated augmentation method resulted in significantly higher mean aesthetic scores than the forehead augmentation method (forehead augmentation: 2.2 ± 1.0; integrated augmentation: 3.7 ± 0.5; P < .001). Table 3. Aesthetic Scores after Forehead Augmentation Surgery by Two Reviewers Characteristic Forehead augmentation method (n = 34) Integrated augmentation method (n = 41) P Reviewer 1 < .001*  Excellent; n (%) 4 (11.8) 33 (80.5)  Good; n (%) 5 (14.7) 6 (14.6)  Fair; n (%) 16 (47.1) 2 (4.9)  Poor; n (%) 9 (26.5) 0 (0.0)  Mean ± SD 2.1 ± 0.9 3.8 ± 0.5 < .001† Reviewer 2 < .001*  Excellent; n (%) 6 (17.6) 30 (73.2)  Good; n (%) 7 (20.6) 8 (19.5)  Fair; n (%) 12 (35.3) 3 (7.3)  Poor; n (%) 9 (26.5) 0 (0.0)  Mean ± SD 2.3 ± 1.1 3.7 ± 0.6 < .001† Average scores of two reviewers  Mean ± SD 2.2 ± 1.0 3.7 ± 0.5 < .001† Characteristic Forehead augmentation method (n = 34) Integrated augmentation method (n = 41) P Reviewer 1 < .001*  Excellent; n (%) 4 (11.8) 33 (80.5)  Good; n (%) 5 (14.7) 6 (14.6)  Fair; n (%) 16 (47.1) 2 (4.9)  Poor; n (%) 9 (26.5) 0 (0.0)  Mean ± SD 2.1 ± 0.9 3.8 ± 0.5 < .001† Reviewer 2 < .001*  Excellent; n (%) 6 (17.6) 30 (73.2)  Good; n (%) 7 (20.6) 8 (19.5)  Fair; n (%) 12 (35.3) 3 (7.3)  Poor; n (%) 9 (26.5) 0 (0.0)  Mean ± SD 2.3 ± 1.1 3.7 ± 0.6 < .001† Average scores of two reviewers  Mean ± SD 2.2 ± 1.0 3.7 ± 0.5 < .001† Aesthetic evaluation: Excellent, 4 points; Good, 3 points; Fair, 2 points; Poor, 1 point. P-value for comparison between the forehead augmentation group and the integrated augmentation group (*Mann–Whitney U test; †unpaired t test). View Large Table 3. Aesthetic Scores after Forehead Augmentation Surgery by Two Reviewers Characteristic Forehead augmentation method (n = 34) Integrated augmentation method (n = 41) P Reviewer 1 < .001*  Excellent; n (%) 4 (11.8) 33 (80.5)  Good; n (%) 5 (14.7) 6 (14.6)  Fair; n (%) 16 (47.1) 2 (4.9)  Poor; n (%) 9 (26.5) 0 (0.0)  Mean ± SD 2.1 ± 0.9 3.8 ± 0.5 < .001† Reviewer 2 < .001*  Excellent; n (%) 6 (17.6) 30 (73.2)  Good; n (%) 7 (20.6) 8 (19.5)  Fair; n (%) 12 (35.3) 3 (7.3)  Poor; n (%) 9 (26.5) 0 (0.0)  Mean ± SD 2.3 ± 1.1 3.7 ± 0.6 < .001† Average scores of two reviewers  Mean ± SD 2.2 ± 1.0 3.7 ± 0.5 < .001† Characteristic Forehead augmentation method (n = 34) Integrated augmentation method (n = 41) P Reviewer 1 < .001*  Excellent; n (%) 4 (11.8) 33 (80.5)  Good; n (%) 5 (14.7) 6 (14.6)  Fair; n (%) 16 (47.1) 2 (4.9)  Poor; n (%) 9 (26.5) 0 (0.0)  Mean ± SD 2.1 ± 0.9 3.8 ± 0.5 < .001† Reviewer 2 < .001*  Excellent; n (%) 6 (17.6) 30 (73.2)  Good; n (%) 7 (20.6) 8 (19.5)  Fair; n (%) 12 (35.3) 3 (7.3)  Poor; n (%) 9 (26.5) 0 (0.0)  Mean ± SD 2.3 ± 1.1 3.7 ± 0.6 < .001† Average scores of two reviewers  Mean ± SD 2.2 ± 1.0 3.7 ± 0.5 < .001† Aesthetic evaluation: Excellent, 4 points; Good, 3 points; Fair, 2 points; Poor, 1 point. P-value for comparison between the forehead augmentation group and the integrated augmentation group (*Mann–Whitney U test; †unpaired t test). View Large Neither reviewer scored any of the patients who received integrated augmentation with poor aesthetic results (Figure 5). A few of those patients had only fair aesthetic results, however, because of visible implant edges at the connecting portion around the temporal fusion lines. Two representative patients who were treated using the integrated method and their aesthetic scores are shown in Figures 6 and 7. Figure 5. View largeDownload slide Distribution of aesthetic evaluations for the forehead augmentation and integrated augmentation groups by two reviewers. Figure 5. View largeDownload slide Distribution of aesthetic evaluations for the forehead augmentation and integrated augmentation groups by two reviewers. Figure 6. View largeDownload slide (A, C) Preoperative and (B, D) 19-month postoperative photographs demonstrating this 38-year-old woman who underwent integrated forehead and temporal augmentation with a prefabricated methyl methacrylate implant. The implant improved the temporal hollowing, providing a rejuvenating and balancing effect to the facial appearance. The patient received an aesthetic score of 4 (Excellent) from the two reviewers. Figure 6. View largeDownload slide (A, C) Preoperative and (B, D) 19-month postoperative photographs demonstrating this 38-year-old woman who underwent integrated forehead and temporal augmentation with a prefabricated methyl methacrylate implant. The implant improved the temporal hollowing, providing a rejuvenating and balancing effect to the facial appearance. The patient received an aesthetic score of 4 (Excellent) from the two reviewers. Figure 7. View largeDownload slide (A, C) Preoperative and (B, D) 3-year postoperative photographs demonstrating this 22-year-old man who underwent integrated forehead and temporal augmentation with a prefabricated methyl methacrylate implant, dorsal augmentation, upper blepharoplasty, and an infrabrow skin excision because he desired a facial appearance like that of a Caucasian. The patient received an aesthetic score of 4 (Excellent) from the two reviewers. Figure 7. View largeDownload slide (A, C) Preoperative and (B, D) 3-year postoperative photographs demonstrating this 22-year-old man who underwent integrated forehead and temporal augmentation with a prefabricated methyl methacrylate implant, dorsal augmentation, upper blepharoplasty, and an infrabrow skin excision because he desired a facial appearance like that of a Caucasian. The patient received an aesthetic score of 4 (Excellent) from the two reviewers. Complications and Revisional Surgeries There were no major complications; however, there were some minor complications (Table 4). There were no statistically significant differences in hair loss, acne-like rash, seroma, facial nerve injury, or scalp numbness between the two groups. No significant differences in the need for implant adjustment or occipital scar revision between the two groups were observed; however, posttreatment implant removal (one [2%] vs. six [18%]; P < .05) and filler injection for touch-up (one [2%] vs. six [18%]; P < .05) were significantly less frequent after integrated augmentation than after forehead augmentation. Table 4. Complications and Revisional Surgeries After Forehead Augmentation Surgery Characteristic Forehead augmentation method (n = 34) Integrated augmentation method (n = 41) P* Complication  Acne-like rash; n (%) 2 (5.9) 2 (4.9) > .999  Facial nerve injury; n (%) 1 (2.9) 1 (2.4) > .999  Scalp numbness; n (%) 1 (2.9) 1 (2.4) > .999  Hair loss; n (%) 1 (2.9) † 0 (0.0) .453  Seroma; n (%) 0 (0.0) 1 (2.4) > .999 Revision surgery  Implant removal; n (%) 6 (17.6) 1 (2.4) .042  Filler injection; n (%) 6 (17.6) 1 (2.4) .042  Implant adjustment; n (%) 4 (11.8) 2 (4.9) .401  Occipital scar revision; n (%) 2 (5.9) 1 (2.4) .587 Characteristic Forehead augmentation method (n = 34) Integrated augmentation method (n = 41) P* Complication  Acne-like rash; n (%) 2 (5.9) 2 (4.9) > .999  Facial nerve injury; n (%) 1 (2.9) 1 (2.4) > .999  Scalp numbness; n (%) 1 (2.9) 1 (2.4) > .999  Hair loss; n (%) 1 (2.9) † 0 (0.0) .453  Seroma; n (%) 0 (0.0) 1 (2.4) > .999 Revision surgery  Implant removal; n (%) 6 (17.6) 1 (2.4) .042  Filler injection; n (%) 6 (17.6) 1 (2.4) .042  Implant adjustment; n (%) 4 (11.8) 2 (4.9) .401  Occipital scar revision; n (%) 2 (5.9) 1 (2.4) .587 *P-value for comparison between the forehead augmentation group and the integrated augmentation group (Fisher’s exact test). †Two areas of hair loss (diameter, approximately 1–2 cm each), resolved after implant removal. View Large Table 4. Complications and Revisional Surgeries After Forehead Augmentation Surgery Characteristic Forehead augmentation method (n = 34) Integrated augmentation method (n = 41) P* Complication  Acne-like rash; n (%) 2 (5.9) 2 (4.9) > .999  Facial nerve injury; n (%) 1 (2.9) 1 (2.4) > .999  Scalp numbness; n (%) 1 (2.9) 1 (2.4) > .999  Hair loss; n (%) 1 (2.9) † 0 (0.0) .453  Seroma; n (%) 0 (0.0) 1 (2.4) > .999 Revision surgery  Implant removal; n (%) 6 (17.6) 1 (2.4) .042  Filler injection; n (%) 6 (17.6) 1 (2.4) .042  Implant adjustment; n (%) 4 (11.8) 2 (4.9) .401  Occipital scar revision; n (%) 2 (5.9) 1 (2.4) .587 Characteristic Forehead augmentation method (n = 34) Integrated augmentation method (n = 41) P* Complication  Acne-like rash; n (%) 2 (5.9) 2 (4.9) > .999  Facial nerve injury; n (%) 1 (2.9) 1 (2.4) > .999  Scalp numbness; n (%) 1 (2.9) 1 (2.4) > .999  Hair loss; n (%) 1 (2.9) † 0 (0.0) .453  Seroma; n (%) 0 (0.0) 1 (2.4) > .999 Revision surgery  Implant removal; n (%) 6 (17.6) 1 (2.4) .042  Filler injection; n (%) 6 (17.6) 1 (2.4) .042  Implant adjustment; n (%) 4 (11.8) 2 (4.9) .401  Occipital scar revision; n (%) 2 (5.9) 1 (2.4) .587 *P-value for comparison between the forehead augmentation group and the integrated augmentation group (Fisher’s exact test). †Two areas of hair loss (diameter, approximately 1–2 cm each), resolved after implant removal. View Large For all patients combined, there were four patients who developed an acne-like rash on the forehead that subsided spontaneously within 6 months; two patients who had facial nerve palsy that resolved within 6 months; and two patients who developed scalp numbness and paresthesia (resolved in one patient after 8 months; persistent in one patient for >1 year). Three patients received scar revision because of wide scarring or alopecia along the incision line. One patient had a seroma that subsided after therapeutic syringe aspiration was performed twice. One patient had hair loss in two areas (each, 1–2 cm) behind the anterior hairline at 2 years after surgery, each the size of a coin, that resolved after implant removal at the patient’s request. The exact cause of this symptom remains unknown. DISCUSSION Our results support the hypothesis that clinical outcomes of our new integrated procedure would be superior to those of forehead augmentation with in situ contoured methyl methacrylate implants. According to the aesthetic evaluations by two reviewers, visible implant edges and deteriorated temporal hollowing, which were frequently associated with the forehead augmentation method, were avoided with the integrated augmentation method. Methyl Methacrylate Materials The present study indicates that methyl methacrylate is a unique material, enabling the custom fabrication of contours requested by the patient and facilitating the optimal augmentation of the forehead and temple.1,8,12 The greatest advantage of using methyl methacrylate for aesthetic reconstructive surgery is its morphological plasticity, which enables the fabrication of custom contours in accordance with the patients’ requests. When methyl methacrylate is applied in situ, the adjacent tissue, especially the temporal muscle, may be damaged by the exothermic reaction during polymerization; however, this risk can be avoided by prefabricating the implant.3,19–22 In addition, the acrylic resin is a foreign body that may cause an allergic or autoimmune reaction, infection, extrusion, extravasation, tissue erosion, hematoma, or seroma.8,14,15,23–25 In the present study, we observed no major adverse complications. We also have not had a single case of infection or wound dehiscence. The occipital coronal approach, in which the incision did not overlap the placed implant, may contribute to the prevention of infection or wound dehiscence. The long-term potential complications involve implant exposure, bone erosion, and implant fragmentation; however, we have observed no cases of such complications during the follow-up period in our study. Although we have demonstrated early success with our method, longer-term follow-up is still required to fully evaluate the safety and implant retention rate. This is an important consideration in outcome studies, as aesthetic problems with foreign bodies may arise over time, as in other operations using alloplastic implants. Newly Designed Integrated Forehead and Temporal Implant During the early days of our practice of forehead contouring, the shape and range of implants were similar to those of implants in the methods previously described;8,12–15 the area targeted for forehead augmentation with an in situ implant was restricted to the area between the temporal lines (Figure 2A).3–6,8,12,13,15 The edges of the implant were carefully molded around the bony skeleton, and the lateral edges were placed beneath the temporalis muscles, which were repositioned and secured to the implant.12,13,26 Despite these adjustments, lateral edges of the implant were frequently visible after surgery.26 The overlying soft-tissue envelope sometimes became thinner over time, causing the implant edges to become more conspicuous (Figure 8).12 In addition, forehead augmentation occasionally accentuated temporal hollowing, resulting in disharmonious features in the upper third of the face (Figure 1).26 Figure 8. View largeDownload slide (A) Preoperative (B) 1-year postoperative and (C) 10-year postoperative photographs demonstrating this 24-year-old woman who underwent forehead augmentation with an in-situ methyl methacrylate implant. Her forehead tissue became progressively thinner, causing the implant edges to become more conspicuous. Figure 8. View largeDownload slide (A) Preoperative (B) 1-year postoperative and (C) 10-year postoperative photographs demonstrating this 24-year-old woman who underwent forehead augmentation with an in-situ methyl methacrylate implant. Her forehead tissue became progressively thinner, causing the implant edges to become more conspicuous. The key issue was that the site targeted for established forehead augmentation using methyl methacrylate as well as silicone implants was restricted to the area between the temporal lines. Our proposal in this study is that combined temporal augmentation should always be taken into consideration for forehead augmentation. Temporal augmentation is commonly conducted by placing a prosthetic implant into the temporal fossa beneath the temporal muscle.27 If the forehead and temporal augmentations are independently performed, the boundary between the forehead and temple can become clearer without continuity at the temporal line. It is therefore of critical importance to contour the forehead and temple with a continuous plane to achieve a well-balanced and smooth-surfaced forehead. Thus, we developed an implant that covers the forehead and temples in a continuous surface extending laterally into the temporal hairlines (Figure 4). Tips for Implant Prefabrication Prefabricating the implant is the most important step in achieving aesthetically pleasing results. We first had to identify the ideal skull shape in the forehead region. Based on our observation of hundreds of subjectively beautiful Asian models and actresses, the ideal profile of the forehead was determined to be relatively vertical in the lower two-thirds, with the upper third declined toward the anterior hairline. The ideal implant was also fabricated to have a smooth surface without any irregularities, be natural-looking (avoiding over-prominence), and be borderless between the forehead and temporal region. The supraorbital ridge and glabella region should be meticulously adjusted relative to the radix to create a dorsal aesthetic line. Caution should be taken to avoid an overaggressive forehead and maintain the racial characteristics of Asian beauty: the implant should be less than 5 mm at its maximum thickness. The principal reason for implant removal in the study was an undesirable over-corrected forehead feature; five of the seven patients requested implant removal due to over-correction. Surgeons must consider such characteristics when fabricating custom-made implants. Even when all factors are considered, fabrication of the abovementioned ideal implant requires considerable expertise and experience. The Placement Layer of the Temporal Implant The placement layer of the temporal implant remains controversial. When we began performing this technique in July 2010, posttreatment thinning of the overlying soft tissue coverage was our primary concern, as subcutaneous temporal implants can expand and stretch the overlying skin. Such thinning of the skin can have negative consequences, such as allowing the patient to easily feel the implant. We considered two main factors to underlie posttreatment thinning of the overlying soft tissue coverage. First, the underlying structure is strongly implicated. In our method, the completed one-unit implant is divided into three units; these units are then connected with nylon sutures during surgery and held in a stable position by the surrounding fibrotic capsule. At the same time, the temporal pieces are allowed vertical mobility on the temporalis muscle, which may help prevent progressive thinning of the soft tissue coverage because the underlying temporalis muscles work as buffer material under the implant. Second, the thickness of the temporal pieces is also associated with the thinning of the skin. Temporal pieces were routinely fabricated to be less than 3 mm in thickness in our study, regardless of the severity of patients’ temporal hollowing. The main role of the temporal pieces is to prevent the visible edge of the forehead implant, and not to correct temporal hollowing. Despite concerns of thinning skin over time due to implant placement over the temporalis muscle, no such cases were observed during the follow-up period. However, we carefully educate patients on the importance of returning to our clinic if they have an eventful posttreatment course. Ancillary Procedures Integrated forehead and temporal augmentation required some ancillary procedures to achieve aesthetically harmonious facial features (Table 2). The nasal dorsum can be consistently affected by altering the contour and dimensions of the forehead/glabella/radix complex. A cranial radix position provides a longer nasal dorsum, whereas a caudal position delineates a shorter nasal dorsum. A deep radix reduces the nasofrontal angle, whereas a high radix enlarges the nasofrontal angle. For this reason, we routinely performed dorsal augmentation to optimize aesthetic balance between the nose and forehead for patients who requested glabella and radix augmentation. The vertical height of the forehead was an important factor in the overall aesthetic of the forehead. In our opinion, the ideal distance between the supraorbital rim and the frontal hairline was 65–70 mm. We, therefore, recommended a forehead lift to raise the anterior hairline for patients whose vertical height of the forehead was <60 mm. Forehead lift was performed simultaneous to augmentation, using a method similar to that for endoscopic brow lift. The frontal hairline was pulled posteriorly and secured with fixation screws at the hairline. A desirable frontal hairline position and shape could also be achieved using laser hair removal. The position of the eyebrows was also important, especially for patients who requested supraorbital ridge augmentation. We performed eyebrow lifts for patients who had a low eyebrow position, with scoring of the supraorbital periosteum and internal screw fixation. For the patients with a high eyebrow position, we performed infrabrow blepharoplasty. Study Limitations There are inherent limitations associated with this retrospective study, including the relatively small sample size and the relatively short follow-up period. In addition, the amount of methyl methacrylate cement used for each patient may have affected the complication rates; however, we could not evaluate this because we added and shaved off cement repeatedly while fabricating the implant. As patient-reported outcomes are becoming popular considerations in the field of plastic surgery, an assessment of patient satisfaction after surgery is necessary and presently underway. Another limitation was the having photographs to score aesthetic outcomes; this process may require validation against clinical face- to-face scoring, even for experienced plastic surgeons. Based on our results and experiences, we advocate that integrated forehead and temporal augmentation be considered an excellent alternative to forehead augmentation. To our knowledge, this is the first study to examine combined temporal and forehead augmentation using alloplastic implants. A 3D printing-assisted model consisting of both a bony skeleton and temporalis muscles provided innovative insight to forehead contouring surgery. Our newly designed implant is unique in that the forehead and temporal pieces yield a continuous plane despite being placed as separate layers; the vertical mobility of temporal pieces may help prevent progressive thinning of the soft tissue coverage. Further study is required to examine the effectiveness of this procedure with a higher number of patients and a longer follow-up period. CONCLUSIONS The biggest advantage of using methyl methacrylate for forehead augmentation procedure is its morphological plasticity, which enables the fabrication of custom contours around both forehead/glabella/supraorbital and temporal region in accordance with the patients’ requests. The results of our study suggest that integrated forehead and temporal augmentation with prefabricated methyl methacrylate may be the optimal available procedure for forehead augmentation, resulting in a rejuvenating and balancing effect on facial appearance. Supplementary Material This article contains supplementary material located online at www.aestheticsurgeryjournal.com. Acknowledgments The authors thank Ms Sakiko Katsumata for creating the artwork for this article. The authors also thank Dr Yuzo Komuro and Ms Mizuho Kamisawa for the invaluable contributions to this article. Disclosures The authors declared no potential conflicts of interest with respect to the research, authorship, and publication of this article. Funding The authors received no financial support for the research, authorship, and publication of this article. REFERENCES 1. Whitaker LA , Morales L Jr , Farkas LG . Aesthetic surgery of the supraorbital ridge and forehead structures . 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Reprints and permission: journals.permissions@oup.com This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)

Journal

Aesthetic Surgery JournalOxford University Press

Published: Oct 15, 2018

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