Clinical Outcomes of Symptomatic Neuroma Resection and Reconstruction with Processed Nerve Allograft

Current Concepts of the Management of Painful Traumatic Peripheral Nerve Neuromas

Painful neuromas are a complex clinical condition that results in notable disability and functional impairment after injury to a peripheral nerve. When regenerating axons lack a distal target, they form a stump neuroma. Up to 60% of neuromas are painful because of mechanical sensitivity and crosstalk between nerve fibers. Clinical evaluation includes a thorough history and physical examination followed by directed diagnostic imaging and procedures to assess pain generators and their effect on quality of life. Nonsurgical management options may include pharmacological interventions, desensitization strategies, injections, and therapies to reduce pain perception and improve function. Surgical interventions, such as nerve reconstruction by direct repair or grafting, redirection to alternative targets, and containment of regenerating axons by relocation into innervated tissues or in grafts, are considered when conservative measures fail. A comprehensive and individualized treatment plan is crucial for optimizing patient outcomes with painful neuromas. The plan should consider the underlying pathology, pain generators, and psychosocial factors contributing to the patient's pain.

Challenges in the surgical treatment of neuroma in continuity in the upper extremity using human acellular nerve allografts

The restoration of nerve function after the injury might be complicated by the development of a disorganized fibrous mass-a neuroma. This results in sensory and/or motor deficits and pain that can be severely debilitating. Surgical excision of the painful neuroma may leave a gap, which can be bridged using autografts or allografts. The main objectives of this study were to obtain 1-year clinical results in patients who underwent excision and reconstruction of a painful neuroma in continuity using decellularized allografts after nerve lesions in the upper extremity. In a prospective cohort study, we evaluated 21 consecutive patients. The patients were evaluated for pain, motor, and sensory function of the hand as well as with patient-reported outcomes. The results showed meaningful sensory recovery in 47% (≥S3), persisting cold intolerance in 48%, disabling hypersensitivity in 48%, and new neuroma formation proximal to or within the allograft in 25% of patients, one year post-operatively. Q-DASH showed 52% of patients with poor results. Overall, 43% of the patients had persisting pain in rest and activity. Measuring muscle strength showed grip strength of 60% and a pinch of 58% of the strength measured in the uninjured hand, which was statistically significant. Even with the excision of a neuroma in continuity and reconstruction with human acellular nerve allograft, limited functional outcome, pain, cold intolerance, and hyperesthesia may persist in the treated patients. There is also the risk of new neuroma formation proximal to or within the allograft.

Comparative Effectiveness Systematic Review and Meta-analysis of Peripheral Nerve Repair Using Direct Repair and Connector-assisted Repair

Background

This clinical literature systematic review and meta-analysis were performed to assess differences in outcomes between nerves repaired with direct repair (DR) and connector-assisted repair (CAR).

Methods

A systematic literature review for DR and CAR was performed. Studies from 1980 through August 2023 were included if DR or CAR repairs were performed in upper extremities with nerve gaps less than 5 mm and reported sensory Medical Research Council Classification (MRCC) outcomes or equivalent. Comparative analyses were planned for meaningful recovery (MR) rate (at both S3 and S3+ or better), postsurgical neuroma, cold intolerance, altered sensation, pain, and revision rate.

Results

There were significant differences in MR rates for CAR and DR. At the MRCC S3 threshold, 96.1% of CAR and 81.3% of DR achieved MR (P < 0.0001). At the MRCC S3+ threshold, 87.1% of CAR and 54.2% of DR achieved this higher threshold of MR (P < 0.0001). There were no differences in neuroma rate or pain scores in our dataset. Altered sensation (dysesthesia, paresthesia, hyperesthesia, or hypersensitivity) was not discussed in any CAR studies, so no analysis could be performed. The revision rate for both procedures was 0%. The proportion of patients with cold intolerance was 46.2% in the DR studies, which was significantly higher than the 10.7% of patients in the CAR group.

Conclusions

Significantly more patients achieved sensory MR and fewer had cold intolerance when the CAR technique, instead of the DR technique, was performed to repair peripheral nerve injuries.

Beyond the limiting gap length: peripheral nerve regeneration through implantable nerve guidance conduits

Peripheral nerve damage results in the loss of sensorimotor and autonomic functions, which is a significant burden to patients. Furthermore, nerve injuries greater than the limiting gap length require surgical repair. Although autografts are the preferred clinical choice, their usage is impeded by their limited availability, dimensional mismatch, and the sacrifice of another functional donor nerve. Accordingly, nerve guidance conduits, which are tubular scaffolds engineered to provide a biomimetic environment for nerve regeneration, have emerged as alternatives to autografts. Consequently, a few nerve guidance conduits have received clinical approval for the repair of short-mid nerve gaps but failed to regenerate limiting gap damage, which represents the bottleneck of this technology. Thus, it is still necessary to optimize the morphology and constituent materials of conduits. This review summarizes the recent advances in nerve conduit technology. Several manufacturing techniques and conduit designs are discussed, with emphasis on the structural improvement of simple hollow tubes, additive manufacturing techniques, and decellularized grafts. The main objective of this review is to provide a critical overview of nerve guidance conduit technology to support regeneration in long nerve defects, promote future developments, and speed up its clinical translation as a reliable alternative to autografts.

Neuromas cause severe residual problems at long-term despite surgery

Pain, and disabilities after neuroma surgery, using patient reported outcome measurements (PROMs), were evaluated by QuickDASH and a specific Hand Questionnaire (HQ-8). The 69 responding individuals (response rate 61%; 59% women; 41% men; median follow up 51 months) reported high QuickDASH score, pain on load, cold sensitivity, ability to perform daily activities and sleeping difficulties. Individuals reporting impaired ability to perform daily activities and sleeping problems had higher scores for pain, stiffness, weakness, numbness/tingling, cold sensitivity and QuickDASH. Only 17% of individuals reported no limitations at all. No differences were observed between sexes. Surgical methods did not influence outcome. Symptoms and disabilities correlated moderately-strongly to each other and to ability to perform regular daily activities as well as to sleeping difficulties. Pain, cold sensitivity, sleeping difficulties and limitation to perform daily activities were associated to higher QuickDASH. A weak association was found between follow up time and QuickDASH score as well as pain on load, but not cold sensitivity. A major nerve injury was frequent among those with limitations during work/performing other regular daily activities. Despite surgical treatment, neuromas cause residual problems, which affect the capacity to perform daily activities and ability to sleep with limited improvement in long-term.

Update on Upper Limb Neuroma Management

Painful terminal neuromas in the upper limb due to nerve injury are common. Neuroma symptoms include a sharp and burning sensation, cold intolerance, dysesthesia, pain, numbness, and paresthesia. These symptoms could have a negative impact on the functional ability of the patient and quality of life. In addition, Prostheses use might be abandoned by amputees due to neuroma-induced pain. Many clinicians face challenges while managing neuromas. Contemporary "active" methods like regenerative peripheral nerve interface (RPNI), targeted muscle reinnervation (TMR), and processed nerve allograft repair (PNA) are replacing the conventional "passive" approaches such as excision, transposition, and implantation techniques. RPNI involves inducing axonal sprouting by transplanting the free end of a peripheral nerve into a free muscle graft. TMR includes reassigning the role of the peripheral nerve by the transfer of the distal end of a pure sensory or a mixed peripheral nerve to a motor nerve of a nearby muscle segment. To give the peripheral nerve a pathway to re-innervate its target tissue, PNA entails implanting a sterile extracellular matrix prepared from decellularized and regenerated human nerve tissue with preserved epineurium and fascicles. Of these, RPNI and TMR appear to hold a promising treatment for nerve-ending neuromas and prevent their relapse. In contrast, PNA may reduce neuroma pain and allow meaningful nerve repair. The aim of this article is to provide an overview of the newer approaches of TMR, RPNI, and PNA and discuss their implications, surgical techniques, and reported consequences.

Procedure Costs of Peripheral Nerve Graft Reconstruction

Peripheral nerve injuries not repaired in an effective and timely manner may lead to permanent functional loss and/or pain. For gaps greater than 5 mm, autograft has been the gold standard. Allograft has recently emerged as an attractive alternative, delivering comparable functional recovery without risk of second surgical site morbidities. Cost is an important factor when considering surgical options, and with a paucity of nerve repair cost data, this study aimed to compare allograft and autograft procedure costs.

Methods

A retrospective cross-sectional observational study using the US all-payer PINC AI Healthcare Database examined facility procedure costs and cost drivers in patients undergoing allograft or autograft repair of an isolated single peripheral nerve injury between January 2018 and August 2020. Inpatient repairs were limited to nerve-specific DRGs. Multivariable regression evaluated risk-adjusted procedure cost differences.

Results

Peripheral nerve graft repairs (n = 1363) were more frequent in the outpatient setting, and more than half involved the use of allograft nerve. Procedure costs for allograft and autograft repair were not significantly different in the outpatient (P = 0.43) or inpatient (P = 0.71) setting even after controlling for other risk factors. Operating room cost was significantly higher for autograft in outpatient (P < 0.0001) but not inpatient (P = 0.46), whereas allograft implant cost was significantly higher in both settings (P < 0.0001).

Conclusions

No significant differences in procedure costs for autograft and allograft repair in inpatient and outpatient settings were found using real-world data. Future research should explore longer-term costs.

Muscle-in-Vein Conduits for the Treatment of Symptomatic Neuroma of Sensory Digital Nerves

Background: Considering the debilitating burden of neuroma resulting in a significant loss of function and excruciating pain, the use of muscle-in-vein conduits (MVCs) for the reconstruction of painful neuroma of sensory nerves of the fingers was assessed. Methods: We retrospectively analyzed 10 patients who underwent secondary digital nerve repair by MVCs. The recovery of sensibility was evaluated by static and moving two-point discrimination (2PDs, 2PDm) and Semmes-Weinstein monofilament testing (SWM). The minimum follow-up was set 12 months after the operation. Results: The median period between trauma and nerve repair was 13.4 weeks (IQR 53.5). After neuroma resection, defects ranged from 10–35 mm (mean 17.7 mm, SD 0.75). The successful recovery of sensibility was achieved in 90% of patients after a median follow-up of 27.0 months (IQR 31.00). The mean 2PDs and 2PDm was 8.1 mm (SD 3.52) and 5.2 mm (SD 2.27), respectively. Assessment by SWM resulted in a mean value of 3.54 (SD 0.69). Reduction in pain was achieved among all patients; eight patients reported the complete relief of neuropathic pain. There was no recurrence of neuroma in any patient. Conclusions: Muscle-in-vein conduits provide an effective treatment for painful neuroma of digital nerves, resulting in satisfactory restoration of sensory function and relief of pain.