933 The Glass Half Full? A Case Of Cutaneous Neuroma Formation Post Laceration Of First Web-Space Of The Hand

Introduction neuromas are lesions resulting from abnormal nerve regeneration following a peripheral nerve injury and may cause severe pain. Method we present a case of a 54-year-old female who developed a painful cutaneous lesion over the first web-space of the hand following an untreated glass laceration 3 years previously. Results surgical resection revealed a 100% transection of ulnar digital nerve (UDN) of thumb with regeneration into the skin. A posterior interosseous nerve (PIN) nerve graft was required to bridge the resulting 15mm gap. Histopathology revealed a 12x12mm neuroma extending into dermis. Conclusions cutaneous neuroma is a rare consequence of penetrating trauma. This case highlights the need for prompt assessment of penetrating injuries to reduce risk of neuroma formation.

Sensate Neurovascular Island Flap for Thumb Reconstruction

Thumb pulp defects require adequate reconstruction for satisfactory sensate function and aesthetic appearance. We report a reconstructive case using a sensate neurovascular island flap raised from the ulnar side of the middle finger for a tactile thumb pad defect. The flap was elevated as a modified version of the conventional heterodigital neurovascular island flap in order to restore thumb sensation without the “double-sensibility” phenomenon. The ulnar digital nerve of the flap was sectioned at the middle phalanx level of the donor digit and coaptated to the ulnar and radial digital nerves of the thumb through end-to-side and end-to-end neurorrhaphy. The remaining radial digital nerve of the donor finger was preserved, and the proximal end of the sectioned nerve was coaptated end-to-side to the radial digital nerve to prevent neuroma formation. No postoperative complications including venous congestion were observed. This technique is a relatively simple and reliable option for reconstructing thump pulp defects.

Neuroma Prevention and Implantation Effects of NEUROCAP in Rat Sciatic Nerve Model

Introduction Symptomatic neuroma with neuropathic pain can develop following peripheral nerve injury. Current interventions for symptomatic neuroma have unpredictable results. NEUROCAP (Polyganics, Groningen, The Netherlands) is a bioresorbable nerve capping device intended to protect a peripheral nerve end and separate the nerve from the surrounding environment, to prevent the recurrence of a symptomatic neuroma. Materials and Methods This study aims to assess the implantation effects of the NEUROCAP device in a rat sciatic nerve model during 12 months (±2 days). Forty-one adult male Sprague-Dawley rats were used in this study. They were randomly divided into a capping or test group, or a noncapping or control group for different time points of survival (12 weeks, 6 months, and 12 months). The objective of this study was evaluated regarding procedural data, adverse events, clinical observations, and histopathology. Results The overall general health of the animals was adequate throughout the study, with the exception of autotomy during the first 4 months of survival. Eight animals were euthanized early due to autotomy, excluded from the study and seven of them have been replaced. Autotomy was an expected outcome and a known limitation of the animal model, particularly as this was a full sciatic nerve transection model. Neuroma formation was observed in the control group while there was no neuroma formation present in the test group. The control group showed increased nerve outgrowth and more chaotic fascicles in comparison with the test group. The test group also had a higher percentage of myelinated fibers compared to the control group. These results indicate a preventive mode of action of the NEUROCAP with regard to neuroma formation after nerve transection in a rat sciatic nerve model. Conclusion The results indicate that NEUROCAP is safe and effective in preventing the recurrence of neuroma formation and inhibiting nerve outgrowth.

Rapid-stretch injury to peripheral nerves: implications from an animal model

OBJECTIVERapid-stretch nerve injuries are among the most devastating lesions to peripheral nerves, yielding unsatisfactory functional outcomes. No animal model has yet been developed that uses only stretch injury for investigation of the pathophysiology of clinical traction injuries. The authors’ objective was to define the behavioral and histopathological recovery after graded rapid-stretch nerve injury.METHODSFour groups of male B6.Cg-Tg(Thy1-YFP)HJrs/J mice were tested: sham injury (n = 11); stretch within elastic limits (elastic group, n = 14); stretch beyond elastic limits but before nerve rupture (inelastic group, n = 14); and stretch-ruptured nerves placed in continuity (rupture group, n = 16). Mice were injured at 8 weeks of age, comparable with human late adolescence. Behavioral outcomes were assessed using the sciatic functional index (SFI), tapered-beam dexterity, Von Frey monofilament testing, and the Hargreaves method. Nerve regeneration outcomes were assessed by wet muscle weight and detailed nerve histology after 48 days.RESULTSPost hoc biomechanical assessment of strain and deformation confirmed that the differences between the elastic and inelastic cohorts were statistically significant. After elastic injury, there was a temporary increase in foot faults on the tapered beam (p < 0.01) and mild reduction in monofilament sensitivity, but no meaningful change in SFI, muscle weight, or nerve histology. For inelastic injuries, there was a profound and maintained decrease in SFI (p < 0.001), but recovery of impairment was observed in tapered-beam and monofilament testing by days 15 and 9, respectively. Histologically, axon counts were reduced (p = 0.04), muscle atrophy was present (p < 0.01), and there was moderate neuroma formation on trichrome and immunofluorescent imaging. Stretch-ruptured nerves healed in continuity but without evidence of regeneration. Substantial and continuous impairment was observed in SFI (p < 0.001), tapered beam (p < 0.01), and monofilament (p < 0.01 until day 48). Axon counts (p < 0.001) and muscle weight (p < 0.0001) were significantly reduced, with little evidence of axonal or myelin regeneration concurrent with neuroma formation on immunofluorescent imaging.CONCLUSIONSThe 3 biomechanical grades of rapid-stretch nerve injuries displayed consistent and distinct behavioral and histopathological outcomes. Stretch within elastic limits resembled neurapraxic injuries, whereas injuries beyond elastic limits demonstrated axonotmesis coupled with impoverished regeneration and recovery. Rupture injuries uniquely failed to regenerate, despite physical continuity of the nerve. This is the first experimental evidence to correlate stretch severity with functional and histological outcomes. Future studies should focus on the pathophysiological mechanisms that reduce regenerative capacity after stretch injury.

Rapid-stretch injury to peripheral nerves: comparison of injury models

OBJECTIVETraditional animal models of nerve injury use controlled crush or transection injuries to investigate nerve regeneration; however, a more common and challenging clinical problem involves closed traction nerve injuries. The authors have produced a precise traction injury model and sought to examine how the pathophysiology of stretch injuries compares with that of crush and transection injuries.METHODSNinety-five late-adolescent (8-week-old) male mice underwent 1 of 7 injury grades or a sham injury (n > 10 per group): elastic stretch, inelastic stretch, stretch rupture, crush, primary coaptation, secondary coaptation, and critical gap. Animals underwent serial neurological assessment with sciatic function index, tapered beam, and von Frey monofilament testing for 48 days after injury, followed by trichrome and immunofluorescent nerve histology and muscle weight evaluation.RESULTSThe in-continuity injuries, crush and elastic stretch, demonstrated different recovery profiles, with more severe functional deficits after crush injury than after elastic stretch immediately following injury (p < 0.05). However, animals with either injury type returned to baseline performance in all neurological assessments, accompanied by minimal change in nerve histology. Inelastic stretch, a partial discontinuity injury, produced more severe neurological deficits, incomplete return of function, 47% ± 9.1% (mean ± SD) reduction of axon counts (p < 0.001), and partial neuroma formation within the nerve. Discontinuity injuries, including immediate and delayed nerve repair, stretch rupture, and critical gap, manifested severe, long-term neurological deficits and profound axonal loss, coupled with intraneural scar formation. Although repaired nerves demonstrated axon regeneration across the gap, rupture and critical gap injuries demonstrated negligible axon crossing, despite rupture injuries having healed into continuity.CONCLUSIONSStretch-injured nerves present unique pathology and functional deficits compared with traditional nerve injury models. Because of the profound neuroma formation, stretch injuries represent an opportunity to study the pathophysiology associated with clinical injury mechanisms. Further validation for comparison with human injuries will require evaluation in a large-animal model.

Isolated Intermetatarsal Ligament Release as Primary Operative Management for Morton’s Neuroma: Short-term Results

Background Although the precise pathoetiology of Morton’s neuroma remains unclear, chronic nerve entrapment from the overlying intermetatarsal ligament (IML) may play a role. Traditional operative management entails neuroma excision but risks unpredictable formation of stump neuroma. Materials and methods Medical records were examined for adult patients who failed at least 3 months of conservative treatment for symptomatic and recalcitrant Morton’s neuroma and who then underwent isolated IML decompression without neuroma resection. Results A total of 12 patients underwent isolated IML decompression for Morton’s neuroma with an average follow-up of 13.5 months. Visual Analog Pain Scale averaged 6.4 ± 1.8 (4-9) preoperatively and decreased to an average of 2 ± 2.1 (0-7) at final follow-up (P = .002). All patients reported significant improvement. Conclusion Isolated IML release of chronically symptomatic Morton’s neuroma shows promising short-term results regarding pain relief, with no demonstrated risk of recurrent neuroma formation, permanent numbness, or postoperative symptom exacerbation. Level of Evidence: Level IV: Case series