Evaluation of Neurosensory Function Following Inferior Alveolar Nerve Lateralization for Implant Placement

Evaluation of Neurosensory Function Following Inferior Alveolar Nerve Lateralization for Implant... J. Maxillofac. Oral Surg. https://doi.org/10.1007/s12663-018-1124-1 O R I G IN AL ARTI CL E Evaluation of Neurosensory Function Following Inferior Alveolar Nerve Lateralization for Implant Placement 1 1 1 1 • • • • Mukund Rathod Rajesh Ashok Kshirsagar Samir Joshi Sudhir Pawar 1 1 1 • • Vishal Tapadiya Suman Gupta Vrushika Mahajan Received: 13 April 2018 / Accepted: 21 May 2018 The Author(s) 2018 Abstract Conclusion IAN lateralization is a useful method for Background Adequate bone height and width is the most managing the atrophic posterior mandible with dental important parameter for success of implants. Prolonged implants. If done precisely with experienced personnel, it edentulous area in mandibular posterior region is often can provide a worthy option for surgical restoration of associated with atrophy precluding the use of dental atrophic mandible with minimal temporary NDs. implants. Inferior alveolar nerve (IAN) lateralization is a challenging surgical procedure as it involves the exposure Keywords Inferior alveolar nerve (IAN) lateralization of the neurovascular bundle from its compact bony com- Neurosensory disturbances  Semmes–Weinstein partment and adequate retraction while immediate place- monofilaments (SWM)  Mandibular atropy ment of implant. Aim Evaluation of neurosensory disturbances related to IAN lateralization for implant placement in the posterior Introduction atrophic edentulous mandible. Materials and Methods Ten patients above the age of Mandibular atrophy is a consequence of long-term eden- 18 years with an edentulous span in mandibular posterior tulous span in the lower jaw which often leads to functional region showing distance from alveolar crest to IAN B 8 and esthetic problems. Problems include insufficient mm (CBCT) were included in the study. The postoperative retention of the prosthesis, difficulty in speech and masti- analysis of NDs was done using Semmes–Weinstein catory insufficiency [1]. Missing posterior teeth lead to loss Monofilaments (SWM). Readings were made on the 1st of soft tissue support and loss of vertical dimension. This and 7th postoperative day and every month thereafter until gives ‘‘aged face’’ look, prognathic appearance, unhappy the neural sensations were restored. face appearance and a reduced range of expression. Results All patients reported neurosensory disturbance on The prosthetic restoration of the partially edentulous post-op day 1. None of the patients responded to SWM atrophic posterior mandible has proved to be problematic. lesser than 4.56 on first postoperative day, which indicated Historically, for these patients, removable partial denture 100% incidence of neurosensory disturbances. The mini- was the only treatment modality available. This was most mum time required for complete recovery was 2.0 months, often because of lack of adequate ridge height for placing and maximum was 4.0 months. dental implants, thus denying patients a most promising dental rehabilitation option [1–3]. Implant supported prosthesis provide predictable long- term results and deliver a stable functional prosthesis with & Vishal Tapadiya added advantages of esthetics, increased occlusal force, vishal.tapadiya@gmail.com improved masticatory performance and proprioception (Fig. 1). Department of Oral and Maxillofacial Surgery, Bharati Adequate bone height and width is the most important Vidyapeeth Dental College and Hospital, Pune, Maharashtra, parameter for success of implants. Prolonged edentulous India 123 J. Maxillofac. Oral Surg. In this prospective study, we have conducted the eval- uation of NDs related to IAN lateralization for implant placement in the posterior atrophic edentulous mandible. Pre- and postoperative NDs were evaluated by objective analysis using Semmes–Weinstein monofilaments (SWM). The previous studies conducted for evaluation of NDs in IAN lateralization for implant placement were subjective in nature [10–12]. They used evaluation technique like questionnaires which may lack objectivity. In addition, this method does not support a scoring system of NDs for better quantification and communication. The SWM provides objective evaluation and eliminates the bias in the results and introduces an ease of quantification, hence using it enhances the communication and comparison between health professionals [3, 13, 14]. Fig. 1 Semmes–Weinstein monofilament span in mandibular posterior region is often associated with Materials and Methods atrophy precluding the use of dental implants [2]. Inferior alveolar nerve (IAN) lateralization is a chal- From September 2013 to December 2015, ten patients with lenging surgical procedure as it involves the exposure of posterior edentulous areas in the mandible underwent lat- the neurovascular bundle from its compact bony compart- eralization of the inferior alveolar neurovascular bundle ment and adequate retraction while immediate placement and subsequent implant placement at the Department of of implant [2, 4–6]. This procedure requires good clinical Oral and Maxillofacial Surgery, Bharati Vidyapeeth experience, knowledge of the anatomy and ability to treat University, Dental College and Hospital, Pune. All patients potential complications. Neurosensory disturbances (ND) were assessed for incidence, magnitude and duration include temporary or permanent anesthesia, paresthesia, required for recovery from NDs using Semmes–Weinstein dysesthesia and hyperesthesia of the nerve and are the monofilaments (SWM). single most important complication of the procedure [7–9]. In addition to routine investigations required for surgical The risk of fracture of the mandible is also associated due intervention, orthopantomogram (OPG) and cone beam to loss of bone in the atrophied mandible. In previous computerized tomography scan (CBCT) were carried out studies for comparison among surgical techniques of for diagnosis and treatment planning (Fig. 3). ‘‘displacement of the foramen’’ and the ‘‘lateralization of This study was approved by the Research Academy and the inferior alveolar nerve,’’ it has been found that the NDs Ethical Committee of the Institute. are more in cases of displacement of the foramen (Fig. 2). This prospective study included ten patients above the age of 18 years with an edentulous span in mandibular posterior region. It was necessary for the distance from alveolar crest to inferior alveolar nerve B 8 mm (CBCT) to be included in the study. Only patients opting to place Fig. 2 Osteotomy Fig. 3 MSR lateralizer 123 J. Maxillofac. Oral Surg. dental implant for prosthetic restoration were included. None of the patients had systemic conditions precluding minor oral surgical procedures (Fig. 4). Semmes–Weinstein monofilaments are calibrated nylon monofilaments used to measure the patient’s ability to sense a point of pressure. A set of 5 Baseline Tactile SWM Set filaments were used (2.86, 3.61, 4.31, 4.56, and 6.65) for the evaluation. They generate a precise amount of stress over the area of application. The higher the value of the monofilament, the stiffer and more difficult it is to bend. In our study, we used monofilament to evaluate incidence, magnitude and duration of NDs (Fig. 5). In the preoperative evaluation procedure, the patient was seated comfortably with his eyes closed to eliminate visual input. The filaments were applied perpendicular to the skin with enough force to cause the monofilament to buckle for approximately 1 s. The evaluation was carried out at pre- Fig. 5 Nerve lateralization 1 determined 3 points based on the running course of mental nerve for obtaining standardized and comparable results. Readings were obtained for the proposed surgical side as well as the contralateral side which would serve as a control (Fig. 6). The surgical procedure was done under local anesthesia (IAN, Lingual and Long buccal nerve blocks). The incision began from the retromolar region and was carried forward to the mesial portion of the cuspid tooth area, where a vertical relaxing incision was made. A full thickness mucoperiosteal flap was reflected. Mental nerve bundle was located and secured using a specially fabricated Fig. 6 Guiding stent instrument (nerve retractor). For the purpose of IAN lateralization, the corticotomy such as small curettes and spoon excavators were used to marking was done. The corticotomy started 3–4 mm distal remove the trabecular bone and gain access to the neu- to the mental foramen and extended in a distal direction, rovascular bundle. The IAN was mobilized from its posi- 1.5–2 cm distal to the provisional implant position. A small tion and released from the canal using a specially round bur in a straight hand piece with high torque and fabricated instrument. After the complete release from the copious amount of sterile isotonic saline irrigation was canal, the inferior alveolar nerve was lateralized com- used to prepare the corticotomy site. Only hand instruments pletely and held in position till accomplishment of imme- diate implant placement. Pilot drill was used to determine desired location of the implant placement using a prefabricated stent. After com- pletion of the osteotomy with last implant drill, the implant was inserted while protecting the nerve bundle. Implant of longer length (11.5–13 mm) was inserted ensuring that the apical ends of the implants were positioned inferior to the canal. Once the implant was in its final position, the nerve was left back over the lateral aspect of the implant. The autogenous bone-graft obtained from the corticotomy was mixed with Tricalcium phosphate hydroxyapatite (TCP- HA) crystals and placed at the osteotomy site to fill the defect. Suturing was done to achieve primary closure. The suitable medications were prescribed to the patient. Methylcobalamin was prescribed to the patient for Fig. 4 Nerve lateralization 123 J. Maxillofac. Oral Surg. 4 weeks, although its usefulness in nerve recovery is Discussion debatable. Patient was recalled on the first postoperative day, and radiographs were made. Implants help us to overcome most problems associated The postoperative analysis of NDs was done using with traditional prosthesis. However, in patients with SWM filaments as described earlier. Readings were made atrophied mandibles, sufficiently long implant fixtures on the 1st and 7th postoperative day and every month cannot be placed because of potential risk of injury to the thereafter until the neural sensations were restored. inferior alveolar nerve (IAN). If the distance between alveolar crest and superior border of the inferior alveolar canal is less than 8 mm, it is Results recommended to carry out lateralization of inferior alveolar nerve to permit placement of longer implants [4]. A total of ten patients underwent IAN lateralization for For IAN lateralization, the IAN is exposed and it is implant placement in the mandibular posterior edentulous retracted laterally during the implant placement. Following region under local anesthesia and sedation. All patients implant placement, the nerve is repositioned over the lateral were evaluated for incidence, magnitude and duration of aspect of the implant. In this technique, there is direct han- recovery from surgically induced neurosensory distur- dling of the nerve. This commonly leads to temporary neu- bances using Semmes–Weinstein monofilaments. All rosensory disturbances in the region supplied by the nerve in patients were available for the duration of the study. the lower lip and chin area. It would be prudent to note that this study attempts to evaluate neurosensory disturbances Incidence following inferior alveolar nerve lateralization and does not deal with the success of the implants or their prosthesis All patients reported neurosensory disturbance on post-op [15–17]. day 1. None of the patients responded to SWM lesser than In this prospective clinical study, the incidence, mag- 4.56 on first postoperative day, which indicates 100% nitude and duration required for recovery from neurosen- incidence of neurosensory disturbance (Table 1) sory disturbances were evaluated. (n = 10–100.0%). The incidence, magnitude and duration of neurosensory disturbances were evaluated by the light touch test using Magnitude Semmes–Weinstein monofilaments (SWM) at predeter- mined intervals of time. Neurosensory evaluation was The mean value for magnitude of ND on first postoperative carried out on 1st and 7th postoperative day and every day was found to be 4.33 with standard deviation of ± month thereafter until up to such a point where the nerve 0.079. The minimum value on day 1 was 4.31, and max- recovery was complete. imum was 4.56. At the completion of one week, the min- imum value recorded was 3.61 and maximum value recorded was 4.56. Incidence of Neurosensory Disturbances Duration Hashemi [18] evaluated NDs in 82 patients at 110 sites who were treated for IAN lateralization for implant The average time for complete recovery from NDs was. placement. His patients noted NDs in the first week, but the The median time to full neurosensory recovery was sites with NDs decreased to 29 (26%) at the end of the first 3 months. The minimum time required for complete month. This reduced to three sites (3%) at the end of the recovery was 2.0 months, and maximum was 4.0 months. sixth month with no changes from then to the end of the The maximum follow-up required was 4 months. year. Table 1 Bell’s interpretation scale Group Bell’s interpretation scale Manufacturer’s marking (Fmg) Calculated force (gm) Calculated stress (gm/sq mm) Group A Normal 2.83 0.0045–0.07 1.45–4.83 Group B Diminished light touch 3.22–3.61 0.166–0.4 11.1–17.7 Group C Diminished protective sensation 3.84–4.31 0.692–2 19.3–33.1 Group D Loss of protective sensation 4.56–6.65 4–300 47.3–300 Group E Unstable 6.65-more 300 or more 300 or more 123 J. Maxillofac. Oral Surg. Morrison et al. [19] performed 26 IAN transpositions in was 9 patients on 2nd month, 8 patients on 3rd month and 15 patients from 1994 to 1999. After the subjective and remained only 2 patients till 4th month. At the end of 4th objective assessment of neurosensory function author sta- month, they both responded to 2.83 no. monofilaments. The ted that; all the patients reported initial change in the maximum and minimum responsive value of SWM in our sensation lasting approximately for one month. study was 4.56 and 2.83, respectively. The interesting retrospective study by Kan et al. is the In our study, we have evaluated neurosensory distur- only one that compares both surgical techniques of ‘‘dis- bances using Semmes–Weinstein monofilaments which is placement of the foramen’’ and the ‘‘lateralization of the an objective method. These calibrated SWM generates a inferior alveolar nerve’’. He analyzed 21 surgeries (64 precise force over the application area of the skin. These implantations) after 10–67 months. He found out that numerical values make it more appropriate for communi- sensory disorders occurred significantly more often in cases cation and comparison. The Bell’s interpretation scale of displacement of the foramen (66.7%) compared to the makes it easier to aid in its clinical application. lateralization of the nerve (33.3%) [20]. Diaz performed nineteen IAN lateralization procedures on 15 patients using piezotome. He observed that all of the Recovery of Neurosensory Function patients (100%) experienced some numbness during the first week after surgery [1]. Hirsch et al. in 24 mandibular posterior segments per- Our observations are in accordance with the observation formed evaluation of neurosensory disturbance after Infe- of Hashemi et al., Hirsch, Morrison, Kan et al., Lorean rior alveolar nerve transposition and lateralization. They et al., Daiz, Vetromilla et al. [1, 18–23] as there is 100% found that the mean time to full resolution of sensation as incidence of neurosensory disturbance on the first postop- judged subjectively and objectively was 4.7 weeks. The erative day. Our observations are in accordance with the neurosensory disturbance after transposition was 5.7 and observation of earlier authors who stated the 100% inci- 3.8 weeks after lateralization [21]. dence of NDs. We would like to emphasize that in our Zuninga et al. studied 130 patients for IAN and LN objective evaluation, we have found that on the first post- (lingual nerve) injuries. They found the median duration of operative day there was diminished sensation or loss of recovery was 11 months for IAN patients and 5.5 months sensation in all patients as per Bell’s interpretation scale. for LN patients [4]. Morrison et al. [19] performed 26 IAN transpositions in 15 patients, and they found the mean time to neurosensory Magnitude of Neurosensory Disturbance recovery was 16 months (range 6–60 months). Overall, 68 IAN reposition and 11 nerve transposition We have done an objective evaluation for neurosensory procedures were performed by Lorean et al. in 57 patients disturbance using Semmes–Weinstein monofilaments. (46 females and 11 males). The duration of neural distur- These monofilaments consist of unique markings, individ- bances after the surgery ranged from 1 to 6 months. In ually calibrated to deliver its targeted force within a 5% other cases, short-term transient nerve disturbances were standard deviation. In our review of literature, no study reported (for 0–4 weeks). No permanent neural damage could be found using monofilaments as an evaluating was reported [22]. device to assess the magnitude of the NDs. Diaz et al. published a prospective cohort study of IAN Hashemi evaluated NDs in all 110 sites in 82 patients lateralization by piezotome and immediate implant place- who were treated for IAN lateralization for implant ment. They found that 12 patients (80%) reported no neu- placement. The NDs was anesthesia in 81 sites, hypoes- rosensory disturbance during the first check-up 8 weeks after thesia in nine sites, burning in nine sites, pain in eight sites, surgery, 14 patients (93.3% of patients/94.73% of proce- pinching in two sites, and tickling in one site. At the end of dures) had no neurosensory disturbance. Only one patient the first month, NDs disappeared in 81 sites (74%). NDs presented hypoesthesia 2 years after the procedure [1]. were hypoesthesia in 12 sites tickling in 8 sites, burning Khajehahmadi et al. compared effect of nerve lateral- sensation in 5 sites and pain in 4 sites. At the end of the first ization and nerve transposition on intact teeth anterior to month, nine sites of hypoesthesia reported in the first week the mental foramen. They found the numbness of the lower had returned to normal. The most common type of ND was lip at 1 week after the operation was done in both groups. anesthesia (81 sites), and the least common type was After 3 months, lip sensation showed normal results in pinching. The tickling lasted 12 months in two patients both groups, except for one patient in each group who [18]. continued to experience some form of hypoesthesia. This In our study, the numbers of patients with neurosensory abnormal lip sensation persisted at the 12-month follow-up disturbances were 10 (100%) till end of the 1st month; it [24]. 123 J. Maxillofac. Oral Surg. Vetromilla et al. did IAN lateralization in 125 patients References and IAN transposition in 150 patients. The shortest full 1. Dıaz JOF, Gıas N (2013) Rehabilitation of edentulous posterior neurosensory recovery time was 6 months. The longest atrophic mandible inferior alveolar nerve lateralization by mean follow-up time was 49.1 months. At the end of fol- piezotome and immediate implant placement. Int J Oral Max- low-up, 7% of the patients still experienced neurosensory illofac Surg 42:521–526 disturbances [23]. 2. Steinberg MJ, Kelly PD (2015) Implant-related nerve injuries. Dent Clin North Am 59:357–373 In our study, we evaluated 10 cases postoperatively on 3. Miloro M (2005) Diagnosis and management of trigeminal nerve first day, after one week, then monthly up to such a point injuries. J Oral Maxillofac Surg 23:140–141 where the nerve recovery was complete. The maximum 4. Zuniga JR, Meyer RA, Gregg JM, Miloro M, Davis LF (1998) duration required for full recovery of nerve function was The accuracy of clinical neurosensory testing for nerve injury diagnosis. J Oral Maxillofac Surg 56:2–8 4 months. The mean duration was 3 months with a stan- 5. Zuniga JR (2015) Sensory outcomes after reconstruction of lin- dard deviation of ± 0.67 months. Our results do not cor- gual and inferior alveolar nerve discontinuities using processed roborate with observations given by Archie Morrison et al. nerve allograft a case series. J Oral Maxillofac Surg 73:734–744 and Zuninga et al. [5, 19] as in their study they found the 6. B-TN G, Pancko FX, Kraut RA (2009) Outcomes of placing short dental implants in the posterior mandible a retrospective study of mean time to neurosensory recovery was 16 months. 124 cases. J Oral Maxillofac Surg 67:713–717 The median time to full recovery was 3 months. First 7. Kim J-H, Kim S-M, Jung H-J, Kim M-J, Lee J-H (2011) Effective neurosensory recovery was noted in 2nd month. Of the 10 end-to-end repair of inferior alveolar nerve defect by using nerve cases, 2 (20.0%) cases required 2-months for full recovery sliding technique. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 112:E28–E30 from ND, 6 (60.0%) cases required 3 months for full 8. Libersa P, Savignat M, Tonnel A (2007) Neurosensory distur- recovery and 2 (20.0%) cases required 4-months for full bances of the inferior alveolar nerve a retrospective study of recovery from ND. In our study, maximum number of complaints in a 10-year period. Am Assoc Oral Maxillofac Surg J patients (60%) had neurosensory recovery in postoperative Oral Maxillofac Surg 65:1486–1489 9. Lin M-H, Maub L-P, Cochran D, Shieh Y-S, Huang P-H, Huang 3rd month. R-Y (2014) Risk assessment of inferior alveolar nerve injury for In our study remaining 20% of cases recovered in the immediate implant placement in the posterior mandible a virtual 4th month which required follow-up duration of 4 months. implant placement study. J Dent 42:263–270 This is in agreement with the observations of Hirsh et al., 10. Mosgau S, Schultze R, Reich H (1993) Assessment of inferior alveolar and lingual nerve disturbances after dentoalveolar sur- Lorean, Diaz, Khajehahmadi et al., Vetromilla et al. gery and of recovery of sensitivity. Int J Oral Maxillofac Surg [1, 21–24] who indicated duration of neurosensory recov- 22:214–217 ery within 6 months of surgery. The restoration of neu- 11. Paolo G, Chiscia G, Gabrieleb G, Iannettib G (2014) Conserva- rosensory function in our study was 100%. tive surgical and microsurgical techniques for the management of dental implants that impinge on the inferior alveolar nerve. Br J Oral Maxillofac Surg 52:566–568 12. Park Y-T, Kim S-G, Moon S-Y (2012) Indirect compressive Conclusion injury to the inferior alveolar nerve caused by dental implant placement. J Oral Maxillofac Surg 70:E258–E259 13. Poort LJ, Van Neck JW, Van Der Wal KGH (2009) Sensory IAN lateralization is a useful method for managing the testing of inferior alveolar nerve injuries: a review of methods atrophic posterior mandible with dental implants. If done used in prospective studies. J Oral Maxillofac Surg 67:292–300 precisely with experienced personnel, it can provide a 14. Al-Sabbagh M, Okeson JP, Khalaf MW, Bhavsar I (2015) A worthy option for surgical restoration of atrophic mandible persistent pain and neurosensory disturbance after dental implant surgery pathophysiology, etiology, and diagnosis. Dent Clin with minimal temporary NDs. The risk of permanent North Am 59:131–142 damage of the IAN appears to be small. Nevertheless, the 15. Meyer RA, Bagheri SC (2008) Letters to editor a bioabsorbable possibility of postoperative NDs associated with the pro- collagen nerve cuff (NeuraGen) for repair of lingual and inferior cedure should be informed in detail prior to commence- alveolar nerve injuries a case series. J Oral Maxillofac Surg 67:2550–2551. https://doi.org/10.1016/j.joms11.002 ment of the procedure. The incidence of neurosensory 16. Robinson RC, Williams CW (1986) Documentation method for disturbances may be further minimized by advances in inferior alveolar and lingual nerve paresthesias. Oral Surg Oral surgical expertise and improved instrumentation. Med Oral Pathol 62:128–131 17. Shanti RM, Ziccardi VB (2011) Use of decellularized nerve Open Access This article is distributed under the terms of the allograft for inferior alveolar nerve reconstruction a case report. Creative Commons Attribution 4.0 International License (http://crea J Oral Maxillofac Surg 69:550–553 tivecommons.org/licenses/by/4.0/), which permits unrestricted use, 18. Hashemi HM (2010) Neurosensory function following distribution, and reproduction in any medium, provided you give mandibular nerve lateralization for placement of implants. Int J appropriate credit to the original author(s) and the source, provide a Oral Maxillofac Surg 39:452–456 link to the Creative Commons license, and indicate if changes were 19. Morrison A, Chiarot M, Kirby S (2002) Mental nerve function made. after inferior alveolar nerve transposition for placement of dental implants. J Can Dent Assoc 68(1):46–50 123 J. Maxillofac. Oral Surg. 20. Quantius B (2010) Lateralization of the inferior alveolar nerve. 23. Vetromilla BM, Moura LB, Sonego CL, Torriani MA, ChagasJr Implants 3:18–21 OL (2014) Complications associated with inferior alveolar nerve 21. Hirsch JM, Branemark PI (1995) Fixture stability and nerve repositioning for dental implant placement a systematic review. function after transposition and lateralization of the inferior Int J Oral Maxillofac Surg 43:1360–1366 alveolar nerve and fixture installation. Br J Oral Maxillofac Surg 24. Khajehahmadi S, Rahpeyma A, Bidar M, Jafarzadeh H (2013) 33:276–281 Vitality of intact teeth anterior to the mental foramen after 22. Lorean A, Kablan F, Mazor Z, Mijiritsky E, Russe P, Barbu H, inferior alveolar nerve repositioning: nerve transpositioning ver- Levin L (2013) Inferior alveolar nerve transposition and reposi- sus nerve lateralization. Int J Oral Maxillofac Surg 42:1073–1078 tion for dental implant placement in edentulous or partially edentulous mandibles a multicenter retrospective study. Int J Oral Maxillofac Surg 42:656–659 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Journal of Maxillofacial and Oral Surgery Springer Journals

Evaluation of Neurosensory Function Following Inferior Alveolar Nerve Lateralization for Implant Placement

Free
7 pages
Loading next page...
 
/lp/springer_journal/evaluation-of-neurosensory-function-following-inferior-alveolar-nerve-vij5lK6zav
Publisher
Springer Singapore
Copyright
Copyright © 2018 by The Author(s)
Subject
Medicine & Public Health; Oral and Maxillofacial Surgery; Dentistry; Otorhinolaryngology; Plastic Surgery
ISSN
0972-8279
eISSN
0974-942X
D.O.I.
10.1007/s12663-018-1124-1
Publisher site
See Article on Publisher Site

Abstract

J. Maxillofac. Oral Surg. https://doi.org/10.1007/s12663-018-1124-1 O R I G IN AL ARTI CL E Evaluation of Neurosensory Function Following Inferior Alveolar Nerve Lateralization for Implant Placement 1 1 1 1 • • • • Mukund Rathod Rajesh Ashok Kshirsagar Samir Joshi Sudhir Pawar 1 1 1 • • Vishal Tapadiya Suman Gupta Vrushika Mahajan Received: 13 April 2018 / Accepted: 21 May 2018 The Author(s) 2018 Abstract Conclusion IAN lateralization is a useful method for Background Adequate bone height and width is the most managing the atrophic posterior mandible with dental important parameter for success of implants. Prolonged implants. If done precisely with experienced personnel, it edentulous area in mandibular posterior region is often can provide a worthy option for surgical restoration of associated with atrophy precluding the use of dental atrophic mandible with minimal temporary NDs. implants. Inferior alveolar nerve (IAN) lateralization is a challenging surgical procedure as it involves the exposure Keywords Inferior alveolar nerve (IAN) lateralization of the neurovascular bundle from its compact bony com- Neurosensory disturbances  Semmes–Weinstein partment and adequate retraction while immediate place- monofilaments (SWM)  Mandibular atropy ment of implant. Aim Evaluation of neurosensory disturbances related to IAN lateralization for implant placement in the posterior Introduction atrophic edentulous mandible. Materials and Methods Ten patients above the age of Mandibular atrophy is a consequence of long-term eden- 18 years with an edentulous span in mandibular posterior tulous span in the lower jaw which often leads to functional region showing distance from alveolar crest to IAN B 8 and esthetic problems. Problems include insufficient mm (CBCT) were included in the study. The postoperative retention of the prosthesis, difficulty in speech and masti- analysis of NDs was done using Semmes–Weinstein catory insufficiency [1]. Missing posterior teeth lead to loss Monofilaments (SWM). Readings were made on the 1st of soft tissue support and loss of vertical dimension. This and 7th postoperative day and every month thereafter until gives ‘‘aged face’’ look, prognathic appearance, unhappy the neural sensations were restored. face appearance and a reduced range of expression. Results All patients reported neurosensory disturbance on The prosthetic restoration of the partially edentulous post-op day 1. None of the patients responded to SWM atrophic posterior mandible has proved to be problematic. lesser than 4.56 on first postoperative day, which indicated Historically, for these patients, removable partial denture 100% incidence of neurosensory disturbances. The mini- was the only treatment modality available. This was most mum time required for complete recovery was 2.0 months, often because of lack of adequate ridge height for placing and maximum was 4.0 months. dental implants, thus denying patients a most promising dental rehabilitation option [1–3]. Implant supported prosthesis provide predictable long- term results and deliver a stable functional prosthesis with & Vishal Tapadiya added advantages of esthetics, increased occlusal force, vishal.tapadiya@gmail.com improved masticatory performance and proprioception (Fig. 1). Department of Oral and Maxillofacial Surgery, Bharati Adequate bone height and width is the most important Vidyapeeth Dental College and Hospital, Pune, Maharashtra, parameter for success of implants. Prolonged edentulous India 123 J. Maxillofac. Oral Surg. In this prospective study, we have conducted the eval- uation of NDs related to IAN lateralization for implant placement in the posterior atrophic edentulous mandible. Pre- and postoperative NDs were evaluated by objective analysis using Semmes–Weinstein monofilaments (SWM). The previous studies conducted for evaluation of NDs in IAN lateralization for implant placement were subjective in nature [10–12]. They used evaluation technique like questionnaires which may lack objectivity. In addition, this method does not support a scoring system of NDs for better quantification and communication. The SWM provides objective evaluation and eliminates the bias in the results and introduces an ease of quantification, hence using it enhances the communication and comparison between health professionals [3, 13, 14]. Fig. 1 Semmes–Weinstein monofilament span in mandibular posterior region is often associated with Materials and Methods atrophy precluding the use of dental implants [2]. Inferior alveolar nerve (IAN) lateralization is a chal- From September 2013 to December 2015, ten patients with lenging surgical procedure as it involves the exposure of posterior edentulous areas in the mandible underwent lat- the neurovascular bundle from its compact bony compart- eralization of the inferior alveolar neurovascular bundle ment and adequate retraction while immediate placement and subsequent implant placement at the Department of of implant [2, 4–6]. This procedure requires good clinical Oral and Maxillofacial Surgery, Bharati Vidyapeeth experience, knowledge of the anatomy and ability to treat University, Dental College and Hospital, Pune. All patients potential complications. Neurosensory disturbances (ND) were assessed for incidence, magnitude and duration include temporary or permanent anesthesia, paresthesia, required for recovery from NDs using Semmes–Weinstein dysesthesia and hyperesthesia of the nerve and are the monofilaments (SWM). single most important complication of the procedure [7–9]. In addition to routine investigations required for surgical The risk of fracture of the mandible is also associated due intervention, orthopantomogram (OPG) and cone beam to loss of bone in the atrophied mandible. In previous computerized tomography scan (CBCT) were carried out studies for comparison among surgical techniques of for diagnosis and treatment planning (Fig. 3). ‘‘displacement of the foramen’’ and the ‘‘lateralization of This study was approved by the Research Academy and the inferior alveolar nerve,’’ it has been found that the NDs Ethical Committee of the Institute. are more in cases of displacement of the foramen (Fig. 2). This prospective study included ten patients above the age of 18 years with an edentulous span in mandibular posterior region. It was necessary for the distance from alveolar crest to inferior alveolar nerve B 8 mm (CBCT) to be included in the study. Only patients opting to place Fig. 2 Osteotomy Fig. 3 MSR lateralizer 123 J. Maxillofac. Oral Surg. dental implant for prosthetic restoration were included. None of the patients had systemic conditions precluding minor oral surgical procedures (Fig. 4). Semmes–Weinstein monofilaments are calibrated nylon monofilaments used to measure the patient’s ability to sense a point of pressure. A set of 5 Baseline Tactile SWM Set filaments were used (2.86, 3.61, 4.31, 4.56, and 6.65) for the evaluation. They generate a precise amount of stress over the area of application. The higher the value of the monofilament, the stiffer and more difficult it is to bend. In our study, we used monofilament to evaluate incidence, magnitude and duration of NDs (Fig. 5). In the preoperative evaluation procedure, the patient was seated comfortably with his eyes closed to eliminate visual input. The filaments were applied perpendicular to the skin with enough force to cause the monofilament to buckle for approximately 1 s. The evaluation was carried out at pre- Fig. 5 Nerve lateralization 1 determined 3 points based on the running course of mental nerve for obtaining standardized and comparable results. Readings were obtained for the proposed surgical side as well as the contralateral side which would serve as a control (Fig. 6). The surgical procedure was done under local anesthesia (IAN, Lingual and Long buccal nerve blocks). The incision began from the retromolar region and was carried forward to the mesial portion of the cuspid tooth area, where a vertical relaxing incision was made. A full thickness mucoperiosteal flap was reflected. Mental nerve bundle was located and secured using a specially fabricated Fig. 6 Guiding stent instrument (nerve retractor). For the purpose of IAN lateralization, the corticotomy such as small curettes and spoon excavators were used to marking was done. The corticotomy started 3–4 mm distal remove the trabecular bone and gain access to the neu- to the mental foramen and extended in a distal direction, rovascular bundle. The IAN was mobilized from its posi- 1.5–2 cm distal to the provisional implant position. A small tion and released from the canal using a specially round bur in a straight hand piece with high torque and fabricated instrument. After the complete release from the copious amount of sterile isotonic saline irrigation was canal, the inferior alveolar nerve was lateralized com- used to prepare the corticotomy site. Only hand instruments pletely and held in position till accomplishment of imme- diate implant placement. Pilot drill was used to determine desired location of the implant placement using a prefabricated stent. After com- pletion of the osteotomy with last implant drill, the implant was inserted while protecting the nerve bundle. Implant of longer length (11.5–13 mm) was inserted ensuring that the apical ends of the implants were positioned inferior to the canal. Once the implant was in its final position, the nerve was left back over the lateral aspect of the implant. The autogenous bone-graft obtained from the corticotomy was mixed with Tricalcium phosphate hydroxyapatite (TCP- HA) crystals and placed at the osteotomy site to fill the defect. Suturing was done to achieve primary closure. The suitable medications were prescribed to the patient. Methylcobalamin was prescribed to the patient for Fig. 4 Nerve lateralization 123 J. Maxillofac. Oral Surg. 4 weeks, although its usefulness in nerve recovery is Discussion debatable. Patient was recalled on the first postoperative day, and radiographs were made. Implants help us to overcome most problems associated The postoperative analysis of NDs was done using with traditional prosthesis. However, in patients with SWM filaments as described earlier. Readings were made atrophied mandibles, sufficiently long implant fixtures on the 1st and 7th postoperative day and every month cannot be placed because of potential risk of injury to the thereafter until the neural sensations were restored. inferior alveolar nerve (IAN). If the distance between alveolar crest and superior border of the inferior alveolar canal is less than 8 mm, it is Results recommended to carry out lateralization of inferior alveolar nerve to permit placement of longer implants [4]. A total of ten patients underwent IAN lateralization for For IAN lateralization, the IAN is exposed and it is implant placement in the mandibular posterior edentulous retracted laterally during the implant placement. Following region under local anesthesia and sedation. All patients implant placement, the nerve is repositioned over the lateral were evaluated for incidence, magnitude and duration of aspect of the implant. In this technique, there is direct han- recovery from surgically induced neurosensory distur- dling of the nerve. This commonly leads to temporary neu- bances using Semmes–Weinstein monofilaments. All rosensory disturbances in the region supplied by the nerve in patients were available for the duration of the study. the lower lip and chin area. It would be prudent to note that this study attempts to evaluate neurosensory disturbances Incidence following inferior alveolar nerve lateralization and does not deal with the success of the implants or their prosthesis All patients reported neurosensory disturbance on post-op [15–17]. day 1. None of the patients responded to SWM lesser than In this prospective clinical study, the incidence, mag- 4.56 on first postoperative day, which indicates 100% nitude and duration required for recovery from neurosen- incidence of neurosensory disturbance (Table 1) sory disturbances were evaluated. (n = 10–100.0%). The incidence, magnitude and duration of neurosensory disturbances were evaluated by the light touch test using Magnitude Semmes–Weinstein monofilaments (SWM) at predeter- mined intervals of time. Neurosensory evaluation was The mean value for magnitude of ND on first postoperative carried out on 1st and 7th postoperative day and every day was found to be 4.33 with standard deviation of ± month thereafter until up to such a point where the nerve 0.079. The minimum value on day 1 was 4.31, and max- recovery was complete. imum was 4.56. At the completion of one week, the min- imum value recorded was 3.61 and maximum value recorded was 4.56. Incidence of Neurosensory Disturbances Duration Hashemi [18] evaluated NDs in 82 patients at 110 sites who were treated for IAN lateralization for implant The average time for complete recovery from NDs was. placement. His patients noted NDs in the first week, but the The median time to full neurosensory recovery was sites with NDs decreased to 29 (26%) at the end of the first 3 months. The minimum time required for complete month. This reduced to three sites (3%) at the end of the recovery was 2.0 months, and maximum was 4.0 months. sixth month with no changes from then to the end of the The maximum follow-up required was 4 months. year. Table 1 Bell’s interpretation scale Group Bell’s interpretation scale Manufacturer’s marking (Fmg) Calculated force (gm) Calculated stress (gm/sq mm) Group A Normal 2.83 0.0045–0.07 1.45–4.83 Group B Diminished light touch 3.22–3.61 0.166–0.4 11.1–17.7 Group C Diminished protective sensation 3.84–4.31 0.692–2 19.3–33.1 Group D Loss of protective sensation 4.56–6.65 4–300 47.3–300 Group E Unstable 6.65-more 300 or more 300 or more 123 J. Maxillofac. Oral Surg. Morrison et al. [19] performed 26 IAN transpositions in was 9 patients on 2nd month, 8 patients on 3rd month and 15 patients from 1994 to 1999. After the subjective and remained only 2 patients till 4th month. At the end of 4th objective assessment of neurosensory function author sta- month, they both responded to 2.83 no. monofilaments. The ted that; all the patients reported initial change in the maximum and minimum responsive value of SWM in our sensation lasting approximately for one month. study was 4.56 and 2.83, respectively. The interesting retrospective study by Kan et al. is the In our study, we have evaluated neurosensory distur- only one that compares both surgical techniques of ‘‘dis- bances using Semmes–Weinstein monofilaments which is placement of the foramen’’ and the ‘‘lateralization of the an objective method. These calibrated SWM generates a inferior alveolar nerve’’. He analyzed 21 surgeries (64 precise force over the application area of the skin. These implantations) after 10–67 months. He found out that numerical values make it more appropriate for communi- sensory disorders occurred significantly more often in cases cation and comparison. The Bell’s interpretation scale of displacement of the foramen (66.7%) compared to the makes it easier to aid in its clinical application. lateralization of the nerve (33.3%) [20]. Diaz performed nineteen IAN lateralization procedures on 15 patients using piezotome. He observed that all of the Recovery of Neurosensory Function patients (100%) experienced some numbness during the first week after surgery [1]. Hirsch et al. in 24 mandibular posterior segments per- Our observations are in accordance with the observation formed evaluation of neurosensory disturbance after Infe- of Hashemi et al., Hirsch, Morrison, Kan et al., Lorean rior alveolar nerve transposition and lateralization. They et al., Daiz, Vetromilla et al. [1, 18–23] as there is 100% found that the mean time to full resolution of sensation as incidence of neurosensory disturbance on the first postop- judged subjectively and objectively was 4.7 weeks. The erative day. Our observations are in accordance with the neurosensory disturbance after transposition was 5.7 and observation of earlier authors who stated the 100% inci- 3.8 weeks after lateralization [21]. dence of NDs. We would like to emphasize that in our Zuninga et al. studied 130 patients for IAN and LN objective evaluation, we have found that on the first post- (lingual nerve) injuries. They found the median duration of operative day there was diminished sensation or loss of recovery was 11 months for IAN patients and 5.5 months sensation in all patients as per Bell’s interpretation scale. for LN patients [4]. Morrison et al. [19] performed 26 IAN transpositions in 15 patients, and they found the mean time to neurosensory Magnitude of Neurosensory Disturbance recovery was 16 months (range 6–60 months). Overall, 68 IAN reposition and 11 nerve transposition We have done an objective evaluation for neurosensory procedures were performed by Lorean et al. in 57 patients disturbance using Semmes–Weinstein monofilaments. (46 females and 11 males). The duration of neural distur- These monofilaments consist of unique markings, individ- bances after the surgery ranged from 1 to 6 months. In ually calibrated to deliver its targeted force within a 5% other cases, short-term transient nerve disturbances were standard deviation. In our review of literature, no study reported (for 0–4 weeks). No permanent neural damage could be found using monofilaments as an evaluating was reported [22]. device to assess the magnitude of the NDs. Diaz et al. published a prospective cohort study of IAN Hashemi evaluated NDs in all 110 sites in 82 patients lateralization by piezotome and immediate implant place- who were treated for IAN lateralization for implant ment. They found that 12 patients (80%) reported no neu- placement. The NDs was anesthesia in 81 sites, hypoes- rosensory disturbance during the first check-up 8 weeks after thesia in nine sites, burning in nine sites, pain in eight sites, surgery, 14 patients (93.3% of patients/94.73% of proce- pinching in two sites, and tickling in one site. At the end of dures) had no neurosensory disturbance. Only one patient the first month, NDs disappeared in 81 sites (74%). NDs presented hypoesthesia 2 years after the procedure [1]. were hypoesthesia in 12 sites tickling in 8 sites, burning Khajehahmadi et al. compared effect of nerve lateral- sensation in 5 sites and pain in 4 sites. At the end of the first ization and nerve transposition on intact teeth anterior to month, nine sites of hypoesthesia reported in the first week the mental foramen. They found the numbness of the lower had returned to normal. The most common type of ND was lip at 1 week after the operation was done in both groups. anesthesia (81 sites), and the least common type was After 3 months, lip sensation showed normal results in pinching. The tickling lasted 12 months in two patients both groups, except for one patient in each group who [18]. continued to experience some form of hypoesthesia. This In our study, the numbers of patients with neurosensory abnormal lip sensation persisted at the 12-month follow-up disturbances were 10 (100%) till end of the 1st month; it [24]. 123 J. Maxillofac. Oral Surg. Vetromilla et al. did IAN lateralization in 125 patients References and IAN transposition in 150 patients. The shortest full 1. Dıaz JOF, Gıas N (2013) Rehabilitation of edentulous posterior neurosensory recovery time was 6 months. The longest atrophic mandible inferior alveolar nerve lateralization by mean follow-up time was 49.1 months. At the end of fol- piezotome and immediate implant placement. Int J Oral Max- low-up, 7% of the patients still experienced neurosensory illofac Surg 42:521–526 disturbances [23]. 2. Steinberg MJ, Kelly PD (2015) Implant-related nerve injuries. Dent Clin North Am 59:357–373 In our study, we evaluated 10 cases postoperatively on 3. Miloro M (2005) Diagnosis and management of trigeminal nerve first day, after one week, then monthly up to such a point injuries. J Oral Maxillofac Surg 23:140–141 where the nerve recovery was complete. The maximum 4. Zuniga JR, Meyer RA, Gregg JM, Miloro M, Davis LF (1998) duration required for full recovery of nerve function was The accuracy of clinical neurosensory testing for nerve injury diagnosis. J Oral Maxillofac Surg 56:2–8 4 months. The mean duration was 3 months with a stan- 5. Zuniga JR (2015) Sensory outcomes after reconstruction of lin- dard deviation of ± 0.67 months. Our results do not cor- gual and inferior alveolar nerve discontinuities using processed roborate with observations given by Archie Morrison et al. nerve allograft a case series. J Oral Maxillofac Surg 73:734–744 and Zuninga et al. [5, 19] as in their study they found the 6. B-TN G, Pancko FX, Kraut RA (2009) Outcomes of placing short dental implants in the posterior mandible a retrospective study of mean time to neurosensory recovery was 16 months. 124 cases. J Oral Maxillofac Surg 67:713–717 The median time to full recovery was 3 months. First 7. Kim J-H, Kim S-M, Jung H-J, Kim M-J, Lee J-H (2011) Effective neurosensory recovery was noted in 2nd month. Of the 10 end-to-end repair of inferior alveolar nerve defect by using nerve cases, 2 (20.0%) cases required 2-months for full recovery sliding technique. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 112:E28–E30 from ND, 6 (60.0%) cases required 3 months for full 8. Libersa P, Savignat M, Tonnel A (2007) Neurosensory distur- recovery and 2 (20.0%) cases required 4-months for full bances of the inferior alveolar nerve a retrospective study of recovery from ND. In our study, maximum number of complaints in a 10-year period. Am Assoc Oral Maxillofac Surg J patients (60%) had neurosensory recovery in postoperative Oral Maxillofac Surg 65:1486–1489 9. Lin M-H, Maub L-P, Cochran D, Shieh Y-S, Huang P-H, Huang 3rd month. R-Y (2014) Risk assessment of inferior alveolar nerve injury for In our study remaining 20% of cases recovered in the immediate implant placement in the posterior mandible a virtual 4th month which required follow-up duration of 4 months. implant placement study. J Dent 42:263–270 This is in agreement with the observations of Hirsh et al., 10. Mosgau S, Schultze R, Reich H (1993) Assessment of inferior alveolar and lingual nerve disturbances after dentoalveolar sur- Lorean, Diaz, Khajehahmadi et al., Vetromilla et al. gery and of recovery of sensitivity. Int J Oral Maxillofac Surg [1, 21–24] who indicated duration of neurosensory recov- 22:214–217 ery within 6 months of surgery. The restoration of neu- 11. Paolo G, Chiscia G, Gabrieleb G, Iannettib G (2014) Conserva- rosensory function in our study was 100%. tive surgical and microsurgical techniques for the management of dental implants that impinge on the inferior alveolar nerve. Br J Oral Maxillofac Surg 52:566–568 12. Park Y-T, Kim S-G, Moon S-Y (2012) Indirect compressive Conclusion injury to the inferior alveolar nerve caused by dental implant placement. J Oral Maxillofac Surg 70:E258–E259 13. Poort LJ, Van Neck JW, Van Der Wal KGH (2009) Sensory IAN lateralization is a useful method for managing the testing of inferior alveolar nerve injuries: a review of methods atrophic posterior mandible with dental implants. If done used in prospective studies. J Oral Maxillofac Surg 67:292–300 precisely with experienced personnel, it can provide a 14. Al-Sabbagh M, Okeson JP, Khalaf MW, Bhavsar I (2015) A worthy option for surgical restoration of atrophic mandible persistent pain and neurosensory disturbance after dental implant surgery pathophysiology, etiology, and diagnosis. Dent Clin with minimal temporary NDs. The risk of permanent North Am 59:131–142 damage of the IAN appears to be small. Nevertheless, the 15. Meyer RA, Bagheri SC (2008) Letters to editor a bioabsorbable possibility of postoperative NDs associated with the pro- collagen nerve cuff (NeuraGen) for repair of lingual and inferior cedure should be informed in detail prior to commence- alveolar nerve injuries a case series. J Oral Maxillofac Surg 67:2550–2551. https://doi.org/10.1016/j.joms11.002 ment of the procedure. The incidence of neurosensory 16. Robinson RC, Williams CW (1986) Documentation method for disturbances may be further minimized by advances in inferior alveolar and lingual nerve paresthesias. Oral Surg Oral surgical expertise and improved instrumentation. Med Oral Pathol 62:128–131 17. Shanti RM, Ziccardi VB (2011) Use of decellularized nerve Open Access This article is distributed under the terms of the allograft for inferior alveolar nerve reconstruction a case report. Creative Commons Attribution 4.0 International License (http://crea J Oral Maxillofac Surg 69:550–553 tivecommons.org/licenses/by/4.0/), which permits unrestricted use, 18. Hashemi HM (2010) Neurosensory function following distribution, and reproduction in any medium, provided you give mandibular nerve lateralization for placement of implants. Int J appropriate credit to the original author(s) and the source, provide a Oral Maxillofac Surg 39:452–456 link to the Creative Commons license, and indicate if changes were 19. Morrison A, Chiarot M, Kirby S (2002) Mental nerve function made. after inferior alveolar nerve transposition for placement of dental implants. J Can Dent Assoc 68(1):46–50 123 J. Maxillofac. Oral Surg. 20. Quantius B (2010) Lateralization of the inferior alveolar nerve. 23. Vetromilla BM, Moura LB, Sonego CL, Torriani MA, ChagasJr Implants 3:18–21 OL (2014) Complications associated with inferior alveolar nerve 21. Hirsch JM, Branemark PI (1995) Fixture stability and nerve repositioning for dental implant placement a systematic review. function after transposition and lateralization of the inferior Int J Oral Maxillofac Surg 43:1360–1366 alveolar nerve and fixture installation. Br J Oral Maxillofac Surg 24. Khajehahmadi S, Rahpeyma A, Bidar M, Jafarzadeh H (2013) 33:276–281 Vitality of intact teeth anterior to the mental foramen after 22. Lorean A, Kablan F, Mazor Z, Mijiritsky E, Russe P, Barbu H, inferior alveolar nerve repositioning: nerve transpositioning ver- Levin L (2013) Inferior alveolar nerve transposition and reposi- sus nerve lateralization. Int J Oral Maxillofac Surg 42:1073–1078 tion for dental implant placement in edentulous or partially edentulous mandibles a multicenter retrospective study. Int J Oral Maxillofac Surg 42:656–659

Journal

Journal of Maxillofacial and Oral SurgerySpringer Journals

Published: Jun 2, 2018

References

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create lists to
organize your research

Export lists, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off