INTRODUCTION: Symptomatic neuromas contribute significantly to morbidity in post-amputation patients, typically occurring within 2–4 months after the initial amputation, and often require surgical revision.1 A multitude of surgical treatment options exist to address symptomatic neuromas without a definitive gold standard including regenerative peripheral nerve interfaces (RPNI), TMR, neurorrhaphy, transposition, nerve graft, and excision and covering with epineurium or silicon caps.2 Whereas painful neuromas are typically addressed only after they develop, skeletal muscle RPNI has been shown to be effective in symptomatic neuroma prevention in extremity amputation3 and dermal RPNI has shown promise in animal models. Dermal RPNI can function as a prophylactic treatment for symptomatic sensory neuroma formation in patients with digit amputation. METHODS: All cases of digit amputation at our institution were retrospectively reviewed from March 2018 to March 2020. We compared prophylactic RPNI in digit amputation to digit amputation patients without prophylactic RPNI as a control using the senior authors’ cases as comparison groups. The average follow-up for the prophylactic RPNI group was 9.4 months (range 4–19 months). The primary outcomes included symptomatic neuroma, infection, and phantom pain. RESULTS: A total of 34 amputations in 23 patients were conducted at our institution by the senior author from March 2018 to March 2020. The total number of nerve transections was 64 (RPNI n = 28; Control n = 36). Patient ages ranged from 17 to 78 years. Indications for amputation included traumatic injury, pressor-associated digit necrosis, necrotizing fasciitis, tenosynovitis, and autoimmune disease. No symptomatic neuromas were noted with RPNI versus two (5.6%) in the control group. There were no significant differences in postoperative infection (RPNI n = 1; Control n = 2). There was a 71% reduction in phantom limb pain. No inclusion cysts were noted in either group. CONCLUSIONS: The use of RPNIs as a prophylactic treatment in digit amputation resulted in zero neuroma formation and significant reduction in phantom limb when compared with the control. Additionally, our study indicated no difference in complications between RPNI and control patients. RPNI may be an effective surgical intervention to reduce painful neuroma formation for patients undergoing digit amputation without increasing risk to the patient. REFERENCES: 1. Vlot MA, Wilkens SC, Chen NC, et al. Symptomatic neuroma following initial amputation for traumatic digital amputation. J Hand Surg. 2018;43(1):86.e1–86.e8. doi:10.1016/j.jhsa.2017.08.021 2. Watson J, Gonzalez M, Romero A, et al. Neuromas of the hand and upper extremity. J Hand Surg. 2010;35(3):499–510. doi:10.1016/j.jhsa.2009.12.019 3. Dumanian GA, Potter BK, Mioton LM, et al. Targeted muscle reinnervation treats neuroma and phantom pain in major limb amputees: a randomized clinical trial. Ann Surg. 2019;270(2):238–246. doi:10.1097/SLA.0000000000003088

Background In patients who have had proximal digit amputation, metacarpal distraction osteogenesis is an option to improve digital length and function. One drawback is that traditional external distraction devices are large and cumbersome; the option of a low-profile internal device is therefore appealing. Internal distractors are commonly used in craniofacial reconstruction, but use in the hand has not been reported. We describe a case series of the novel use of an internal distractor in metacarpal lengthening. Methods In this single-center case series, patients who underwent metacarpal distraction by the senior author using a uniplanar internal distractor were reviewed, and indications, outcomes, and complications were analyzed. Results There were 5 cases in 4 patients (age range: 7-33 years). Indications were traumatic amputation in 4 cases and congenital hypoplasia in 1. All were successfully distracted, with a mean final length gain of 1.3 cm (range: 1.0-1.7 mm). Mean time from device placement to consolidation was 3.5 months. Complications included activation arm site infection in 2 cases, both occurring after the distraction period, necessitating device removal before full consolidation. In these cases, the device was removed after the distraction period and replaced with a Kirschner wire for stabilization through the consolidation period. Conclusions Metacarpal distraction was successfully achieved with an internal distraction device. Although infection was common, it occurred after the distraction period and did not preclude length gain. We feel that this low-profile device offers advantages over cumbersome external devices typically used for metacarpal lengthening.