TY - JOUR
AU - Gottlieb, Lawrence, J
AB - Abstract Under ideal circumstances, severely frostbitten extremities are rapidly rewarmed and treated with thrombolytic therapy within 6 to 24 hours. In an “inner city,” urban environment, most patients who suffer frostbite injuries present in a delayed fashion, sustain repeated injuries further complicated by psychological issues or intoxication, and are rarely ideal candidates for thrombolytic therapy within the prescribed timeframe. We describe our experience with the treatment of urban frostbite injuries. A retrospective review of patients with cold injuries sustained between November 2013 and March 2014 treated at a verified burn center in an urban setting was performed. Fifty-three patients were treated (42 males, 11 females). Average patient age was 41.8 years (range 2–84 years). No patients met criteria for thrombolytic therapy due to multiple freeze-thaw cycles or presentation greater than 24 hours after rewarming. Deep frostbite was seen in 10 patients. Of these patients, nine underwent debridement, resulting in partial limb amputations at levels guided by Tri-phasic technetium (Tc-99m) bone scans. Wound closure and limb-length salvage was then achieved by: free flap coverage (n = 2), local flaps (n = 8), split-thickness skin grafting (n = 22), and secondary intention healing (n = 6). While tissue plasminogen activator has been successful in reducing the need for digital amputation following frostbite injuries, in our experience, this treatment modality is not applicable to the urban patient population who often present late and after cycles of reinjury. Therefore, our approach focused on salvaging limb length with durable coverage, as the injuries were unable to be reversed. The populations affected by frostbite are diverse. Historically, the first reported cases of frostbite were seen in soldiers on military campaigns. Cold injuries nearly eradicated Napoleon’s army during the Russian invasion of 1812 to 1813 and caused over one million causalities in World Wars I and II and Korean Wars.1 An increased interest in outdoor sports led to cold exposure in a different subset of patients, ones who are often mountain rescued and brought swiftly to tertiary care centers for timely, expedient treatment. And finally, there is the urban frostbite population, patients who pose unique barriers to frostbite management. In an “inner city,” urban environment, most patients who suffer frostbite injuries present in a delayed fashion and sustain repeated cold injuries further complicated by psychological issues or intoxication.2 Regardless of the subset of frostbite patient, one fact remains universal—the initial clinical assessment of cold injuries is notoriously unreliable in being able to predict what tissue will recover from freezing. Hence, the well-known adage, “Freeze in January, amputate in July.”3 In the past, patients suffered frostbite injuries during the winter and waited months to allow the injured areas to demarcate and determine the need for and level of amputation. This concept epitomized the difficulties in predicting ultimate tissue demarcation from clinical findings alone. However, beginning in the late 1970s, studies found that triple-phase bone scanning could reliably forecast the microvascular condition of limbs affected by frostbite.4–6 This tool is often utilized early on in treatment protocols to predict potential limb loss and either determine amputation level or attempt to surgically salvage tissue with aggressive soft tissue coverage.7 More recently, many burn centers use early bone scan results to determine patient candidacy for thrombolytic therapy in attempt to salvage compromised limbs. Under ideal circumstances, severely frostbitten extremities are rapidly warmed and treated with thrombolytic therapy within 6 to 24 hours. Twomey et al showed that early administration of tissue plasminogen activator (tPA) can result in complete avoidance of proximal amputation and digital salvage rates of 85 to 90%.8 We aim to describe our experience with the treatment of urban frostbite injuries, focusing on early surgical management and limb-length preservation for patients who are not candidates for thrombolytic therapy due to delayed presentation and/or multiple freeze-thaw cycles. METHODS We performed an Institutional Review Board (IRB)-approved (IRB 17-0820) retrospective chart review of all cold injuries treated at an eight-bed verified urban burn center between November 1, 2013 and March 31, 2014. At that time, our center cared for both adults and children with an associated Level 1 pediatric trauma center and a Level 2 adult trauma center. Patients were admitted from either the emergency room or as direct transfers from outside hospitals. Initial therapy consisted of rewarming, fluid resuscitation as needed, and determining the severity of cold injury, which ranged from frostnip to deep frostbite. Patients with frostnip were treated with ibuprofen 600 mg every 8 hours, aloe vera lotion or cream, and were discharged after ensuring they had proper cold protection. Individuals with superficial frostbite were admitted to the burn unit. Superficial frostbite was characterized by supple tissues, when depressed, which were painful after thawing, often with clear blisters. These clear blisters were aspirated and wound care performed with either topical Silver Sulfadiazine or Mepilex Ag (Mölnlyck, Sweden) dressings. Patients were also placed on ibuprofen and discharged once dressing changes were minimal. Deep frostbite was characterized by firm, woody tissues, which were anesthetic after thawing. These injuries were often accompanied by hemorrhagic blisters. These patients were always admitted, and their suitability for tPA administration was determined. Indications for use of tPA were adapted from previously published and widely accepted treatment protocols9: 1) no improvement on rapid rewarming in tepid water (38–42°C for 15–20 minutes), 2) absent Doppler pulses in limbs and/or digits, 3) limited perfusion on Tc-99m 3-phase bone scan, 4) 24 hours or less since rewarming complete, and 5) no repeated freeze-thaw cycles. If tPA was not indicated or contraindicated, hemorrhagic blisters were debrided and local wound care performed. Similar to published reports, tri-phasic technetium bone scans were performed within 48 hours of admission and were repeated at least 5 days after admission in order to assess bone perfusion.5,10 These early scans determined if the patient was likely to heal or if they were a candidate for surgical salvage. As previously described, patients who had normal blood and bone pool images on tri-phasic technetium bone scans, as well as patients who had little or no blood pool, and diminished, but visible, bone pool images, typically went on to heal with aggressive wound care. However, patients who had little to no flow in either blood or bone pool images were evaluated for surgical salvage.7 RESULTS A total of 53 patients with a spectrum of cold injuries were treated between November 2013 and March 2014 (Table 1). Average age was 41.8 ± 20.3 years (range 2–84 years). The majority of patients tended to be African American (n = 44, 83.0%) and male (n = 42, 79.3%). Ten patients exhibited deep frostbite injuries and were, therefore, theoretically eligible for limb salvage with thrombolytic therapy according to our protocol. However, none of these patients met inclusion criteria for tPA administration due to presentation more than 24 hours after rewarming (n = 10, 100%) and repeated injuries (n = 5, 50%). Patients with deeper injuries tended to be older, have more social issues (drug addiction or alcoholism, homelessness, psychiatric disease) and were of the lowest socioeconomic status, although none of these differences were statistically significant (Table 2). Approximately 17% of all frostbite injuries (90% of deep frostbite injuries) were managed with debridement, which included partial/complete digital amputation or more proximal extremity amputation (Table 3). There was one patient with a deep frostbite injury who refused amputations, even though they were indicated. In order to salvage limb length, patients underwent a variety of reconstructive procedures including split-thickness skin grafting (n = 22), local/perforator flaps (n = 8), and free flaps (n = 2). On average, patients had 2.4 ± 1.7 procedures (range 1–6 procedures) to achieve wound closure. Mean length of hospital stay was 12.5 ± 13.5 days (range 1–48 days). Operative complications included: bleeding/hematoma (two patients) and wound dehiscence (four patients), resulting in open wounds, which eventually healed by secondary intention. Table 1. Demographics of patients with cold-related injuries treated at a single urban burn center Total Patients N = 53 Mean age (years) 41.8 Median age (years) 42.0 Age range (years) 2–84 Gender (%)  Male N = 42 (79.3)  Female N = 11 (20.7) Race (%)  African American N = 44 (83.0)  Caucasian N = 6 (11.3)  Asian N = 3 (5.7) Payor status (%)  Medicaid/none N = 28 (52.8)  Private/student N = 14 (26.4)  Medicare N = 10 (18.9)  Work compensation N = 1 (1.2) Injury classification (%)  Frostnip 16 (30.2)  Superficial frostbite 27 (50.9)  Deep frostbite 10 (18.9) Injury location (%)  Upper extremity N = 28 (52.8)  Lower extremity N = 16 (30.2)  Head and neck N = 5 (9.4)  Upper and lower extremities N = 3 (5.7)  Other N = 1 (1.9) Total Patients N = 53 Mean age (years) 41.8 Median age (years) 42.0 Age range (years) 2–84 Gender (%)  Male N = 42 (79.3)  Female N = 11 (20.7) Race (%)  African American N = 44 (83.0)  Caucasian N = 6 (11.3)  Asian N = 3 (5.7) Payor status (%)  Medicaid/none N = 28 (52.8)  Private/student N = 14 (26.4)  Medicare N = 10 (18.9)  Work compensation N = 1 (1.2) Injury classification (%)  Frostnip 16 (30.2)  Superficial frostbite 27 (50.9)  Deep frostbite 10 (18.9) Injury location (%)  Upper extremity N = 28 (52.8)  Lower extremity N = 16 (30.2)  Head and neck N = 5 (9.4)  Upper and lower extremities N = 3 (5.7)  Other N = 1 (1.9) View Large Table 1. Demographics of patients with cold-related injuries treated at a single urban burn center Total Patients N = 53 Mean age (years) 41.8 Median age (years) 42.0 Age range (years) 2–84 Gender (%)  Male N = 42 (79.3)  Female N = 11 (20.7) Race (%)  African American N = 44 (83.0)  Caucasian N = 6 (11.3)  Asian N = 3 (5.7) Payor status (%)  Medicaid/none N = 28 (52.8)  Private/student N = 14 (26.4)  Medicare N = 10 (18.9)  Work compensation N = 1 (1.2) Injury classification (%)  Frostnip 16 (30.2)  Superficial frostbite 27 (50.9)  Deep frostbite 10 (18.9) Injury location (%)  Upper extremity N = 28 (52.8)  Lower extremity N = 16 (30.2)  Head and neck N = 5 (9.4)  Upper and lower extremities N = 3 (5.7)  Other N = 1 (1.9) Total Patients N = 53 Mean age (years) 41.8 Median age (years) 42.0 Age range (years) 2–84 Gender (%)  Male N = 42 (79.3)  Female N = 11 (20.7) Race (%)  African American N = 44 (83.0)  Caucasian N = 6 (11.3)  Asian N = 3 (5.7) Payor status (%)  Medicaid/none N = 28 (52.8)  Private/student N = 14 (26.4)  Medicare N = 10 (18.9)  Work compensation N = 1 (1.2) Injury classification (%)  Frostnip 16 (30.2)  Superficial frostbite 27 (50.9)  Deep frostbite 10 (18.9) Injury location (%)  Upper extremity N = 28 (52.8)  Lower extremity N = 16 (30.2)  Head and neck N = 5 (9.4)  Upper and lower extremities N = 3 (5.7)  Other N = 1 (1.9) View Large Table 2. Comparison of patient demographics between frostnip/superficial frostbite and deep frostbite injuries Deep Frostbite N = 10 All Others N = 43 Mean age (years) 52.8 39.3 Age range (years) 34–71 2–84 Social factors  Uninsured/Medicaid (%) 9 (90.0) 19 (44.2)  Homeless (%) 5 (50.0) 2 (4.7)  Psychiatric history (%) 7 (70.0) 10 (23.3)  Substance abuse (%) 7 (70.0) 4 (9.3) Time to presentation (%)  >24 h after initial rewarming 10 (100.0) 27 (62.8)  <24 h after initial rewarming 0 (0) 16 (37.2) Repeated Injuries (%) 5 (50.0) 0 (0) Deep Frostbite N = 10 All Others N = 43 Mean age (years) 52.8 39.3 Age range (years) 34–71 2–84 Social factors  Uninsured/Medicaid (%) 9 (90.0) 19 (44.2)  Homeless (%) 5 (50.0) 2 (4.7)  Psychiatric history (%) 7 (70.0) 10 (23.3)  Substance abuse (%) 7 (70.0) 4 (9.3) Time to presentation (%)  >24 h after initial rewarming 10 (100.0) 27 (62.8)  <24 h after initial rewarming 0 (0) 16 (37.2) Repeated Injuries (%) 5 (50.0) 0 (0) View Large Table 2. Comparison of patient demographics between frostnip/superficial frostbite and deep frostbite injuries Deep Frostbite N = 10 All Others N = 43 Mean age (years) 52.8 39.3 Age range (years) 34–71 2–84 Social factors  Uninsured/Medicaid (%) 9 (90.0) 19 (44.2)  Homeless (%) 5 (50.0) 2 (4.7)  Psychiatric history (%) 7 (70.0) 10 (23.3)  Substance abuse (%) 7 (70.0) 4 (9.3) Time to presentation (%)  >24 h after initial rewarming 10 (100.0) 27 (62.8)  <24 h after initial rewarming 0 (0) 16 (37.2) Repeated Injuries (%) 5 (50.0) 0 (0) Deep Frostbite N = 10 All Others N = 43 Mean age (years) 52.8 39.3 Age range (years) 34–71 2–84 Social factors  Uninsured/Medicaid (%) 9 (90.0) 19 (44.2)  Homeless (%) 5 (50.0) 2 (4.7)  Psychiatric history (%) 7 (70.0) 10 (23.3)  Substance abuse (%) 7 (70.0) 4 (9.3) Time to presentation (%)  >24 h after initial rewarming 10 (100.0) 27 (62.8)  <24 h after initial rewarming 0 (0) 16 (37.2) Repeated Injuries (%) 5 (50.0) 0 (0) View Large Table 3. Surgical management of frostbitten extremities for patients with deep frostbite Total Patients N = 10 Affected digits N = 72 Amputations  Digital N = 26  Proximal (transmetatarsal, Lisfranc, partial hand) N = 7 Patients requiring debridement (%)* N = 9 (90%) Reconstructive modality†  Secondary intention N = 6  Skin grafting N = 22  Local flap N = 8  Free flap N = 2 Mean number of procedures 2.4 Complications  Hematoma/bleeding N = 2  Wound breakdown N = 4 Mean length of stay (days ± SD) 12.5 ± 13.5 Range length of stay (days) 1–48 Total Patients N = 10 Affected digits N = 72 Amputations  Digital N = 26  Proximal (transmetatarsal, Lisfranc, partial hand) N = 7 Patients requiring debridement (%)* N = 9 (90%) Reconstructive modality†  Secondary intention N = 6  Skin grafting N = 22  Local flap N = 8  Free flap N = 2 Mean number of procedures 2.4 Complications  Hematoma/bleeding N = 2  Wound breakdown N = 4 Mean length of stay (days ± SD) 12.5 ± 13.5 Range length of stay (days) 1–48 *Debridement (including amputation) was guided by Tc-99m bone scans in deep injuries. †Data include total number performed for limb salvage of deep injuries. View Large Table 3. Surgical management of frostbitten extremities for patients with deep frostbite Total Patients N = 10 Affected digits N = 72 Amputations  Digital N = 26  Proximal (transmetatarsal, Lisfranc, partial hand) N = 7 Patients requiring debridement (%)* N = 9 (90%) Reconstructive modality†  Secondary intention N = 6  Skin grafting N = 22  Local flap N = 8  Free flap N = 2 Mean number of procedures 2.4 Complications  Hematoma/bleeding N = 2  Wound breakdown N = 4 Mean length of stay (days ± SD) 12.5 ± 13.5 Range length of stay (days) 1–48 Total Patients N = 10 Affected digits N = 72 Amputations  Digital N = 26  Proximal (transmetatarsal, Lisfranc, partial hand) N = 7 Patients requiring debridement (%)* N = 9 (90%) Reconstructive modality†  Secondary intention N = 6  Skin grafting N = 22  Local flap N = 8  Free flap N = 2 Mean number of procedures 2.4 Complications  Hematoma/bleeding N = 2  Wound breakdown N = 4 Mean length of stay (days ± SD) 12.5 ± 13.5 Range length of stay (days) 1–48 *Debridement (including amputation) was guided by Tc-99m bone scans in deep injuries. †Data include total number performed for limb salvage of deep injuries. View Large Case 1 A 43-year-old homeless, schizophrenic male was transferred from a local hospital more than 24 hours after rewarming for evaluation of a deep frostbite injury to his bilateral lower extremities. With inconsistent shelter and protective gear for the month prior to presentation, he had suffered repeated episodes of cold injury. On presentation, his boots were wet and stuck to his feet. His feet were warm, although a bluish discoloration and surrounding cellulitis was noted. There were hemorrhagic blisters overlying the distal metatarsals and proximal phalanges (Figure 1). He had palpable dorsalis pedis pulses bilaterally with absent posterior tibial pulses. Due to his delayed presentation, he was deemed an inappropriate candidate for thrombolytic administration. Local wound care was initiated, and the patient was placed on intravenous antibiotics for his cellulitis. A Tc-99m bone scan was performed on postadmission day 9, which showed no perfusion distal to the metatarsophalangeal (MTP) joints bilaterally. Guided by imaging from the bone scans, debridement of the involved areas was performed on postadmission day 14, which ultimately resulted in amputations of all 10 toes at the MTP joints on each foot (Figure 2). In order to preserve limb length, closure was achieved with bilateral V-to-Y local flaps over the great toe metatarsal heads—the first V-to-Y flap was performed on the right foot at the time of initial surgery, and the second V-to-Y flap was performed in a delayed manner on the left foot, given concern for infection at the time of initial debridement (Figure 3). Subsequent operative debridements of the left heel left the calcaneal bone exposed. Rather than perform an amputation at the ankle joint or above, a distally based sural artery adipose fascial flap with split-thickness skin graft was performed to cover the left heel and salvage the limb (Figure 4). The patient was discharged and seen 3 months after surgery, at which point his wounds had completely healed and he was ambulatory with an assistive prosthesis (Figure 5). Figure 1. View largeDownload slide (A) A 43-year-old homeless, schizophrenic male presented with deep frostbite injury and absent digital pulses (photographs on the day of presentation). He was not a candidate for thrombolytic therapy due to delayed presentation and repeated freeze-thaw cycles. (B) Ultimate preoperative demarcation of bilateral lower extremities on postinjury day 10 (solid line shows planned level of amputation). (C) Preoperative demarcation correlates with Tc-99m bone scans, which depicted poor perfusion distal to the metatarsophalangeal joints in most of the toes (dotted line). Figure 1. View largeDownload slide (A) A 43-year-old homeless, schizophrenic male presented with deep frostbite injury and absent digital pulses (photographs on the day of presentation). He was not a candidate for thrombolytic therapy due to delayed presentation and repeated freeze-thaw cycles. (B) Ultimate preoperative demarcation of bilateral lower extremities on postinjury day 10 (solid line shows planned level of amputation). (C) Preoperative demarcation correlates with Tc-99m bone scans, which depicted poor perfusion distal to the metatarsophalangeal joints in most of the toes (dotted line). Figure 2. View largeDownload slide Amputation of all 10 toes at the metatarsophalangeal (MTP) joints and debridement of the bilateral heels was performed. In some cases, there was evidence of perfusion on bone scan distal to the MTP joint (see dotted line, Figure 1), but would have required a more complex operation (ie, free flap) to close the defect. Therefore, clinical judgment was used and the toes were amputated at the MTP joint. Figure 2. View largeDownload slide Amputation of all 10 toes at the metatarsophalangeal (MTP) joints and debridement of the bilateral heels was performed. In some cases, there was evidence of perfusion on bone scan distal to the MTP joint (see dotted line, Figure 1), but would have required a more complex operation (ie, free flap) to close the defect. Therefore, clinical judgment was used and the toes were amputated at the MTP joint. Figure 3. View largeDownload slide Bilateral V-Y perforator flaps were utilized to salvage the great toe metatarsals to aid with balance in anticipation of future ambulation. Figure 3. View largeDownload slide Bilateral V-Y perforator flaps were utilized to salvage the great toe metatarsals to aid with balance in anticipation of future ambulation. Figure 4. View largeDownload slide (A,B) Following subsequent debridements of devitalized tissue of the left heel, the calcaneal bone was exposed. (C) To preserve limb length, a reverse sural nerve adipose fascial flap from the posterior leg donor site was performed. (D) The local flap was covered with a split-thickness skin graft. Figure 4. View largeDownload slide (A,B) Following subsequent debridements of devitalized tissue of the left heel, the calcaneal bone was exposed. (C) To preserve limb length, a reverse sural nerve adipose fascial flap from the posterior leg donor site was performed. (D) The local flap was covered with a split-thickness skin graft. Figure 5. View largeDownload slide Pictures taken at the 3-month postoperative visit show well-healed wounds on the bilateral feet, with preservation of lower extremity and foot length to allow for ambulation. The right foot (top panel) and left foot (bottom left) are completely healed. Figure 5. View largeDownload slide Pictures taken at the 3-month postoperative visit show well-healed wounds on the bilateral feet, with preservation of lower extremity and foot length to allow for ambulation. The right foot (top panel) and left foot (bottom left) are completely healed. Case 2 A 51-year-old male with polysubstance abuse was admitted from the emergency room with bilateral lower extremity frostbite, 1 week after being exposed to prolonged subzero temperatures at his unheated home (Figure 5). His initial exam showed edema and darkened, blistering skin of his feet. His dorsalis pedis pulses were palpable bilaterally (Figure 6A). Local wound care was started, and the patient was placed on strict bed rest. He was not a candidate for thrombolytic therapy. A Tc-99m bone scan showed decreased blood flow and bone activity to the bilateral toes and distal metatarsals (Figure 6B). On postadmission day 11, the patient went to the operating room for a right transmetatarsal amputation, which was not closed due to concern for infection. A Lisfranc amputation was performed on the left lower extremity, with dorsalis pedis fasciocutaneous flap coverage (Figure 6C). The patient subsequently required additional debridements, including conversion of the Lisfranc amputation to a Chopart-level amputation, as well as coverage of his remaining open wounds with split-thickness skin grafts (Figure 6D). After discharge, the patient missed several follow-up appointments, but was eventually seen in clinic, with well-healed wounds. He was ambulatory with cast shoes and the assistance of crutches (Figure 6E). Figure 6. View largeDownload slide (A) A 53-year-old male presented with a 1-week history of frostbite of his bilateral lower extremities (solid line marks clinically evident area of dermarcation). (B) Local wound care was started and a Tc-99m bone scan was obtained, which showed poor perfusion to his bilateral toes and a portion of his distal metatarsals (dotted line marks boundary of poor perfusion on Tc-99m scan). (C) The patient initially underwent an open transmetatarsal amputation on the right lower extremity, and a Lisfranc amputation with dorsalis pedis flap coverage on the left lower extremity. (D) Due to poor wound healing and infection, the patient required several additional debridements, with eventual coverage of wounds with split-thickness skin grafts. (E) The patient was seen in clinic approximately 3 months after discharge, at which times his wounds were healed, and he was ambulatory in cast shoes with the assistance of crutches. Figure 6. View largeDownload slide (A) A 53-year-old male presented with a 1-week history of frostbite of his bilateral lower extremities (solid line marks clinically evident area of dermarcation). (B) Local wound care was started and a Tc-99m bone scan was obtained, which showed poor perfusion to his bilateral toes and a portion of his distal metatarsals (dotted line marks boundary of poor perfusion on Tc-99m scan). (C) The patient initially underwent an open transmetatarsal amputation on the right lower extremity, and a Lisfranc amputation with dorsalis pedis flap coverage on the left lower extremity. (D) Due to poor wound healing and infection, the patient required several additional debridements, with eventual coverage of wounds with split-thickness skin grafts. (E) The patient was seen in clinic approximately 3 months after discharge, at which times his wounds were healed, and he was ambulatory in cast shoes with the assistance of crutches. Case 3 A 63-year-old homeless female with a psychiatric disorder was admitted with pain, swelling, blistering, and dark discoloration of her bilateral toes (Figure 7A). She was a poor historian, and the extent of her cold exposure was unable to be ascertained. For this reason, she was not a candidate for thrombolytic therapy. Her bone scan showed decreased uptake in the toes (Figure 7B). She refused operative amputation at that time, and was subsequently treated with local wound care. She was eventually discharged from the hospital to an inpatient psychiatric facility. Approximately 1 year later, she returned with repeat frostbite injuries to her bilateral feet. Her feet were gangrenous at the time of admission, and all but two of her toes had autoamputated since her initial discharge. Given that she had undergone multiple repeat freeze-rewarming cycles, the tissue damage was severe and she was not a candidate for thrombolytic therapy (Figure 8). She underwent bilateral transmetatarsal amputations on postadmission day 6, which were left open and local wound care was performed. Once the infection was cleared with topical antimicrobials, she was taken back to the operating room on postadmission day 20 for split-thickness skin grafts to her bilateral feet (Figure 9). Once healed, she was able to ambulate with assistance, with cast shoes in place. She was discharged to a nursing facility and was subsequently lost to follow up. Figure 7. View largeDownload slide (A) A 53-year-old homeless female with a psychiatric disorder was admitted with deep frostbite of all her toes. Given her unclear history and likely multiple free-thaw cycles, she was not a candidate for thrombolysis (solid line marks proposed amputation level). (B) A bone scan obtained on admission shows decreased blood flow to all her toes (dotted line boundary of poor perfusion). She refused operative amputation of her toes. Figure 7. View largeDownload slide (A) A 53-year-old homeless female with a psychiatric disorder was admitted with deep frostbite of all her toes. Given her unclear history and likely multiple free-thaw cycles, she was not a candidate for thrombolysis (solid line marks proposed amputation level). (B) A bone scan obtained on admission shows decreased blood flow to all her toes (dotted line boundary of poor perfusion). She refused operative amputation of her toes. Figure 8. View largeDownload slide The patient returned the following winter with more extensive frostbite injuries to her bilateral feet, which had become gangrenous. She was taken to the operating room for extensive debridement. Since the time of her first admission, 8 of 10 toes had autoamputated after her initial frostbite injury. Figure 8. View largeDownload slide The patient returned the following winter with more extensive frostbite injuries to her bilateral feet, which had become gangrenous. She was taken to the operating room for extensive debridement. Since the time of her first admission, 8 of 10 toes had autoamputated after her initial frostbite injury. Figure 9. View largeDownload slide (A) Bilateral transmetatarsal amputations were performed during the initial surgery, and the infection was managed with topical antimicrobials. (B) Upon return to the operating room, split-thickness skin grafts were used for final coverage of the transmetatarsal amputation stumps. No local flaps were needed, and limb length was preserved to allow for ambulation with cast shoes. Figure 9. View largeDownload slide (A) Bilateral transmetatarsal amputations were performed during the initial surgery, and the infection was managed with topical antimicrobials. (B) Upon return to the operating room, split-thickness skin grafts were used for final coverage of the transmetatarsal amputation stumps. No local flaps were needed, and limb length was preserved to allow for ambulation with cast shoes. DISCUSSION Since the beginning of time, man has battled the elements. The cold, in particular, has proven a lethal opponent throughout history. Human adaption to frigid temperatures is minimal, and survival is dependent upon insulation with protective gear. Of all the proposed protocols for frostbite treatment, rapid rewarming is the most universally accepted. However, this treatment addresses only the ice crystal phase of cellular damage and does not reverse the damage to thrombosed vessels, which is the result of intravascular crystal formation. Intra-arterial crystal formation produces endothelial damage and inflammation leading to clotting, decreased blood flow, and thus, tissue ischemia.11,12 The attempts to reverse vascular injury in frostbitten tissues began with the introduction of tPA in a small pilot study in the 1990s.13 Since then, various centers have implemented thrombolytic therapy in attempts to ameliorate the extent of potential injury in severe frostbite.8 Now with the more widespread use of thrombolytics, there are universally agreed upon contraindications to their administration, including: mental incapacity, severe hypertension, recent trauma or stroke, and bleeding disorders. Thrombolytic therapy is also contraindicated if the injured part has undergone repeated freeze-thaw cycles. In addition, it has been shown that as time from rewarming to administration of tPA increases, there is a decrease in limb and digit salvage.14 Some literature describes warm ischemia time greater than 6, or more commonly 12 hours, as a relative contraindication to tPA use, based on the conclusion that tPA is generally ineffective after this timeframe, while other studies describe greater than 24 hours of warm ischemia time as a contraindication.8,14–16 In our patient population, we used 24 hours after rewarming as a cutoff for initiating tPA therapy. However, even with this timeline, none of our patients met criteria for tPA administration. Of particular importance to the urban frostbite population are the criteria excluding the use of tPA in mentally incapacitated patients and those with delayed presentations who suffer repeated injuries. Although patients placed on thrombolytics are typically kept on strict bedrest, this therapy can be potentially dangerous in the alcoholic or noncompliant patient, where falls can lead to severe head injury and bleeding; nonetheless, mental incapacity will also preclude the ability to consent for treatment. In concordance with other studies, our experience in an inner city burn center confirms the most common risk factors associated with frostbite injury are alcohol and drugs, mental illness, and homelessness.17,18 The struggle with treating the urban frostbite population is evidenced by the patient described in Case 3, who was homeless, had psychiatric/substance abuse issues, and was readmitted 2 years in a row with frostbite injuries, eventually requiring amputations after refusing treatment during her initial stay. None of our patients with deep frostbite met criteria for thrombolytic administration due to the timing of their presentation and recurrent episodes of injury. Thus, in order to salvage limb length, our management of frostbite injuries over the past 30 years has relied upon early debridement of devitalized tissue, guided by Tc-99m bone scans, and salvage of critically exposed structures by coverage local-regional or free flaps.7,19 Like other centers, we have found that Tc-99m scanning is a good predictor of potential digit loss.20,21 Not only is this modality accurate, but it avoids more invasive angiography. Mummification and the eventual need for amputation are likely in patients with absent blood-pool phases and bone uptake. If only a single digit or multiple digital tips are involved, then amputation is performed. Patients who are candidates for surgical salvage undergo repeat triple-phase bone scanning at least 5 days after admission (and their initial Tc-99m scan). We try to adhere to this timeline as frequently as possible as mummification usually starts by day 10, after which salvage of tissue (by coverage with flaps) is no longer possible. Candidates for salvage include those with multidigit or extensive limb involvement. Early identification of critically injured structures allows timely debridement or amputation of tissue that may have otherwise taken weeks to months to demarcate, in accordance with the previous management dogma: “Freeze in January, amputate in July.” When terminally damaged tissue is identified early, before the onset of mummification (ideally within 10 days of injury), unsalvageable tissues that are more prone to ischemia (skin and subcutaneous tissue) can be debrided in an attempt to salvage bone and tendons, which are more able to withstand prolonged ischemia, with coverage by well-vascularized tissue.7 We have found that this allows for improved preservation of limb length. Furthermore, the use of local-regional or free flaps allows additional limb-length salvage, often at the level of the foot or ankle, in cases where typically, more proximal amputations, such as below-knee amputations, would have otherwise been required to facilitate primary closure.22 In looking at the urban frostbite population treated during the study period, one limitation is evident: there was a relative paucity of follow-up data. Given that the majority of the patients who sustained deep frostbite injuries and subsequently underwent limb salvage procedures were either homeless, or suffered from psychiatric/substance abuse disorders, few returned to the office for outpatient follow-up. In the future, if possible, it will be helpful to look at the long-term effects of limb salvage operations in this patient population. CONCLUSION It is important for tertiary referral centers to have established protocols for the management of frostbite injuries. While rapid rewarming remains the mainstay of initial treatment, the paradigm has shifted towards aggressive attempts at injury reversal through the administration of tPA. Although the implementation of thrombolytic therapy has gained widespread acceptance and has been shown to reduce the potential for digital amputations, many urban patients do not meet criteria for administration. Therefore, alternative modalities for the limb salvage in severe frostbite injury should be explored. In treating the inner city, urban population, who often present in a delayed manner and are plagued by repeated injuries, complicated further by homelessness or intoxication, our protocol focuses on early, aggressive debridement and limb salvage with local-regional or free flaps. Financial Disclosure: None of the authors has a financial interest in any of the drugs, products, or devices mentioned in this discussion or the manuscript being discussed. REFERENCES 1. Orr KD , Fainer DC . 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For permissions, please e-mail: 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)
TI - Urban Frostbite: Strategies for Limb Salvage
JF - Journal of Burn Care & Research
DO - 10.1093/jbcr/irz062
DA - 2019-08-14
UR - https://www.deepdyve.com/lp/oxford-university-press/urban-frostbite-strategies-for-limb-salvage-cxd06jAEm0
SP - 613
VL - 40
IS - 5
DP - DeepDyve
ER -