Surgical interventions for the treatment of painful neuroma: a comparative meta-analysis

Outcomes of upper extremity sensory neuromas treated with excision and burial

Background

Upper extremity sensory neuromas can be extremely debilitating leading to pain and dysfunction. Surgical management of neuromas can either be ablative or reconstructive. The primary aim of this study was to examine the outcomes of surgically treated sensory neuromas within the forearm, wrist, and hand with exclusion of digital neuromas.

Methods

A retrospective review was conducted of patients surgically treated for an upper extremity sensory neuroma from a multi-surgeon, single institution database. The types of neuroma, mechanism of injury and the surgical technique utilized for treatment were documented. Patient reported outcomes were collected including resolution of symptoms, pain scores, complications, and need for revision surgery. Averages and proportions were used for analysis.

Results

79 patients were included with mean age of 42.3 years and an average follow-up of 6.7 months. The types of sensory neuromas included 23 dorsal radial sensory, 21 medial antebrachial cutaneous, 15 palmar cutaneous, and 14 dorsal ulnar sensory. Single isolated cases of neuromas were more common (94.9%) than multiple neuromas (5.1%). 67.1% (53/79) of patients experienced pain or hypersensitivity with a mean improvement of 2.0 in the visual analog scale (VAS) following surgery. 6.3% (5/79) required revision surgery, and 82% returned to work in some capacity.

Conclusion

Surgical excision of neuroma and burial into local surrounding tissue can be safely performed with a relatively low reoperation rate. 80% of patients had full resolution or improvement in their symptoms.

A novel animal model of symptomatic neuroma for assessing neuropathic pain

INTRODUCTION

Following amputation, peripheral nerves lack distal targets for regeneration, often resulting in symptomatic neuromas and debilitating neuropathic pain. Animal models can establish a practical method for symptomatic neuroma formation for better understanding of neuropathic pain pathophysiology through behavioral and histological assessments. We created a clinically translatable animal model of symptomatic neuroma to mimic neuropathic pain in patients and assess sexual differences in pain behaviors.

METHODS

Twenty-two male and female rats were randomly assigned to one of two experimental groups: (1) neuroma surgery, or (2) sham surgery. For the neuroma experimental group, the tibial nerve was transected in the thigh, and the proximal segment was placed under the skin for mechanical testing at the site of neuroma. For the sham surgery, rats underwent tibial nerve isolation without transection. Behavioral testing consisted of neuroma-site pain, mechanical allodynia, cold allodynia, and thermal hyperalgesia at baseline, and then weekly over 8 weeks.

RESULTS

Male and female neuroma rats demonstrated significantly higher neuroma-site pain response compared to sham groups starting at weeks 3 and 4, indicating symptomatic neuroma formation. Weekly assessment of mechanical and cold allodynia among neuroma groups showed a significant difference in pain behavior compared to sham groups (p < 0.001). Overall, males and females did not display significant differences in their pain responses. Histology revealed a characteristic neuroma bulb at week 8, including disorganized axons, fibrotic tissue, Schwann cell displacement, and immune cell infiltration.

CONCLUSION

This novel animal model is a useful tool to investigate underlying mechanisms of neuroma formation and neuropathic pain.

The neuroma map: A systematic review of the anatomic distribution, etiologies, and surgical treatment of painful traumatic neuromas

BACKGROUND

This study analyzed all reported cases of painful traumatic neuromas to better understand their anatomic distribution, etiologies, and surgical treatment.

METHODS

PubMed, Embase, Cochrane, and Web of Science were searched in October 2023 for articles describing painful traumatic neuromas.

RESULTS

In total, 414 articles reporting 5,562 neuromas were included and categorized into head/neck, trunk, upper extremity, lower extremity, and autonomic nerves. Distribution was as follows: Head/neck: 82 articles reported on 393 neuromas (93.2% iatrogenic) most frequently involving the lingual (44.3%), cervical plexus (14.9%), great auricular (8.5%), inferior/superior alveolar (8.3%), and occipital (7.2%) nerves. Trunk: 47 articles reported on 554 neuromas (92.9% iatrogenic) most commonly involving the intercostal (35.4%), genitofemoral (14.3%), and pudendal (12.9%) nerves. Upper extremity: 159 articles reported on 2079 neuromas (53.3% after amputation) most frequently involving the digital (46.9%), superficial radial (18.3%), and median (7.0%) nerves. Lower extremity: 128 articles reported on 2,531 neuromas (53.0% after amputation) most commonly involving the sural (17.9%), superficial peroneal (17.3%), and saphenous (16.0%) nerves. Autonomic nerves: 15 articles reported on 53 neuromas (100% iatrogenic) most frequently involving the biliary tract (73.9%) and vagus nerve (14.9%). Compared with the extremities, neuromas in the head/neck and trunk had significantly longer symptom duration before surgical treatment and the nerve end was significantly less frequently reconstructed after neuroma excision.

CONCLUSION

Painful neuromas are predominantly reported in the extremities yet may occur throughout the body primarily after iatrogenic injury. Knowledge of their anatomic distribution from head to toe will encourage awareness to avoid injury and expedite diagnosis to prevent treatment delay.

Management of an Early-Onset, Painful Tibial Nerve Neuroma Using an Autologous Nerve Graft

This case report describes the treatment of a postoperative painful neuroma of the tibial nerve using an autologous nerve graft in a dog. The patient presented with sudden non-weight-bearing lameness 10 days after iatrogenic tibial nerve injury during preparation of a reverse saphenous conduit flap. The dog showed severe pain at the surgical site without nerve deficits. A magnetic resonance imaging examination revealed an enlarged tibial nerve at the injury site, consistent with a neuroma. Analgesics were administered over 11 days, but the patient remained in severe pain and non-weight-bearing. Therefore, surgical resection was recommended. The fusiform neuroma was resected microsurgically, and a saphenous nerve graft was transplanted using an epineural nerve repair technique. Histopathological examination was consistent with a neuroma. The dog showed immediate pain relief and weight-bearing the day after surgery with normal motor function. The dog made a full recovery by the last follow-up 6 mo after surgery. If patients develop pain and lameness following surgery or nerve injury, neuroma formation must be considered, even shortly after surgery. Microsurgical resection and autologous nerve transplantation using an epineural nerve repair technique is a viable method to treat painful neuromas and minimize the risk for recurrence in dogs.

Combined Targeted Muscle Reinnervation With Regenerative Peripheral Nerve Interfaces Decreases Long-Term Narcotic Use in Amputees: A Case Control Study

PURPOSE

Combined targeted muscle reinnervation with regenerative peripheral nerve interfaces ("TMRpni") is a recently described nerve management strategy that leverages beneficial elements of targeted muscle reinnervation (TMR) and regenerative peripheral nerve interface (RPNI) techniques. This study aimed to evaluate the effect of TMRpni on long-term opioid consumption after amputation. We hypothesize that TMRpni decreases chronic opioid consumption in amputees.

METHODS

This is a retrospective cohort study of all patients who underwent TMRpni between 2019 and 2021. These patients were age-matched at a 1:1 ratio with a control group of patients who underwent amputation without TMRpni. Statistical analysis was performed using SPSS Version 28.0.

RESULTS

Thirty-one age-matched pairs of patients in the TMRpni and control groups were included. At 30 days after surgery, there was no significant difference in number of patients who required an additional refill of their opioid prescriptions (45% vs 55%, P = 0.45) or patients who continued to actively use opioids (36% vs 42%, P = 0.60). However, at 90 days after surgery, there was a significantly lower number of patients from the TMRpni group who reported continued opioid use compared with the control group (10% vs 32%, P = 0.03).

CONCLUSIONS

This study demonstrates that TMRpni may translate to decreased rates of chronic opiate use. Continued study is indicated to optimize TMRpni techniques and patient selection and to determine its long-term efficacy.

Economic Cost-Benefit Analysis of Nerve Implanted into Muscle versus Targeted Muscle Reinnervation versus Regenerative Peripheral Nerve Interface, for Treatment of the Painful Neuroma

BACKGROUND

 This study investigated the relative cost utility of three techniques for the management of symptomatic neuromas after neuroma excision: (1) implantation of nerve into muscle, (2) targeted muscle reinnervation (TMR), and (3) regenerative peripheral nerve interface (RPNI).

METHODS

 The costs associated with each procedure were determined using Common Procedural Terminology codes in combination with data from the Centers for Medicaid and Medicare Services Physician and Facility 2020 Fee Schedules. The relative utility of the three procedures investigated was determined using changes in Patient-Reported Outcomes Measurement Information System (PROMIS) and Numeric Rating Scale (NRS) pain scores as reported per procedure. The relative utility of each procedure was reported in terms of quality-adjusted life years (QALYs), as is standard in the literature.

RESULTS

 The least expensive option for the surgical treatment of painful neuromas was nerve implantation into an adjacent muscle. In contrast, for the treatment of four neuromas, as is common postamputation, TMR without a microscope was found to cost $50,061.55 per QALY gained, TMR with a microscope was found to cost $51,996.80 per QALY gained, and RPNI was found to cost $14,069.28 per QALY gained. While RPNI was more expensive than nerve implantation into muscle, it was still below the standard willingness-to-pay threshold of $50,000 per QALY, while TMR was not.

CONCLUSION

 Evaluation of costs and utilities associated with the various surgical options for the management of painful neuromas suggest that nerve implantation into muscle is the least expensive option with the best improvement in QALY, while demonstrating comparable outcomes to TMR and RPNI with regard to pain symptoms.

Minimally invasive scar release by autologous adipose tissue transfer for post-traumatic neuropathic pain

Introduction

Addressing post traumatic lower limb neuropathic pain is challenging across medical specialties. To address this potentially devastating condition, several invasive and non-invasive approaches have been proposed with inconsistent results. Adipose fat transfer (AFT), also known as fat grafting, is a regenerative medicine technique in which a patient's own fat is harvested from one area of the body (usually through liposuction) and then injected into another area for various purposes, such as aesthetic contour enhancement or reconstruction and regeneration of scarred tissues.

Methods

We analyze the effects of fat grafting for neuropathic pain combined with neuroma excision (hybrid technique, hAFT) or alone (AFT). A retrospective review was conducted on 22 patients with neuropathic lower limb pain, after trauma or orthopedic surgery treated with hAFT (n = 9) or AFT (n = 13).

Results

Reduction in VAS scale more than 50 % was observed in 6 patients (66 %) treated with hybrid technique and in eleven patients (85 %) treated with AFT alone. Among these, complete pain reduction (>91 %) was achieved in 33.3 % of hAFT and 54 % of AFT technique. A 3.2 points reduction in VAS was found in the hAFT group versus 5.8 points in the AFT group (p = 0.035).

Conclusion

This pioneering use of AFT emerges as a minimally invasive breakthrough, promising significant improvement in reconstructing scarred subcutaneous tissue and managing neuropathic pain.

Biology and pathophysiology of symptomatic neuromas

ABSTRACT

Neuromas are a substantial cause of morbidity and reduction in quality of life. This is not only caused by a disruption in motor and sensory function from the underlying nerve injury but also by the debilitating effects of neuropathic pain resulting from symptomatic neuromas. A wide range of surgical and therapeutic modalities have been introduced to mitigate this pain. Nevertheless, no single treatment option has been successful in completely resolving the associated constellation of symptoms. While certain novel surgical techniques have shown promising results in reducing neuroma-derived and phantom limb pain, their effectiveness and the exact mechanism behind their pain-relieving capacities have not yet been defined. Furthermore, surgery has inherent risks, may not be suitable for many patients, and may yet still fail to relieve pain. Therefore, there remains a great clinical need for additional therapeutic modalities to further improve treatment for patients with devastating injuries that lead to symptomatic neuromas. However, the molecular mechanisms and genetic contributions behind the regulatory programs that drive neuroma formation-as well as the resulting neuropathic pain-remain incompletely understood. Here, we review the histopathological features of symptomatic neuromas, our current understanding of the mechanisms that favor neuroma formation, and the putative contributory signals and regulatory programs that facilitate somatic pain, including neurotrophic factors, neuroinflammatory peptides, cytokines, along with transient receptor potential, and ionotropic channels that suggest possible approaches and innovations to identify novel clinical therapeutics.

Volume loss during muscle reinnervation surgery is correlated with reduced CMAP amplitude but not reduced force output in a rat hindlimb model

Introduction: Muscle reinnervation (MR) surgery offers rehabilitative benefits to amputees by taking severely damaged nerves and providing them with new denervated muscle targets (DMTs). However, the influence of physical changes to muscle tissue during MR surgery on long-term functional outcomes remains understudied. Methods: Our rat hindlimb model of MR surgery utilizes vascularized, directly neurotized DMTs made from the lateral gastrocnemius (LG), which we employed to assess the impact of muscle tissue size on reinnervation outcomes, specifically pairing the DMT with the transected peroneal nerve. We conducted MR surgery with both DMTs at full volume and DMTs with partial volume loss of 500 mg at the time of surgery (n = 6 per group) and measured functional outcomes after 100 days of reinnervation. Compound motor action potentials (CMAPs) and isometric tetanic force production was recorded from reinnervated DMTs and compared to contralateral naïve LG muscles as positive controls. Results: Reinnervated DMTs consistently exhibited lower mass than positive controls, while DMTs with partial volume loss showed no significant mass reduction compared to full volume DMTs (p = 0.872). CMAP amplitudes were lower on average in reinnervated DMTs, but a broad linear correlation also exists between muscle mass and maximum CMAP amplitude irrespective of surgical group (R2 = 0.495). Surprisingly, neither MR group, with or without volume loss, demonstrated decreased force compared to positive controls. The average force output of reinnervated DMTs, as a fraction of the contralateral LG's force output, approached 100% for both MR groups, a notable deviation from the 9.6% (±6.3%) force output observed in our negative control group at 7 days post-surgery. Tissue histology analysis revealed few significant differences except for a marked decrease in average muscle fiber area of reinnervated DMTs with volume loss compared to positive controls (p = 0.001). Discussion: The results from our rat model of MR suggests that tissue electrophysiology (CMAPs) and kinesiology (force production) may recover on different time scales, with volumetric muscle loss at the time of MR surgery not significantly reducing functional outcome measurements for the DMTs after 100 days of reinnervation.

Approaches to neuropathic amputation-related pain: narrative review of surgical, interventional, and medical treatments

BACKGROUND/IMPORTANCE

Neuropathic amputation-related pain can consist of phantom limb pain (PLP), residual limb pain (RLP), or a combination of both pathologies. Estimated of lifetime prevalence of pain and after amputation ranges between 8% and 72%.

OBJECTIVE

This narrative review aims to summarize the surgical and non-surgical treatment options for amputation-related neuropathic pain to aid in developing optimized multidisciplinary and multimodal treatment plans that leverage multidisciplinary care.

EVIDENCE REVIEW

A search of the English literature using the following keywords was performed: PLP, amputation pain, RLP. Abstract and full-text articles were evaluated for surgical treatments, medical management, regional anesthesia, peripheral block, neuromodulation, spinal cord stimulation, dorsal root ganglia, and peripheral nerve stimulation.

FINDINGS

The evidence supporting most if not all interventions for PLP are inconclusive and lack high certainty. Targeted muscle reinnervation and regional peripheral nerve interface are the leading surgical treatment options for reducing neuroma formation and reducing PLP. Non-surgical options include pharmaceutical therapy, regional interventional techniques and behavioral therapies that can benefit certain patients. There is a growing evidence that neuromodulation at the spinal cord or the dorsal root ganglia and/or peripheral nerves can be an adjuvant therapy for PLP.

CONCLUSIONS

Multimodal approaches combining pharmacotherapy, surgery and invasive neuromodulation procedures would appear to be the most promising strategy for preventive and treating PLP and RLP. Future efforts should focus on cross-disciplinary education to increase awareness of treatment options exploring best practices for preventing pain at the time of amputation and enhancing treatment of chronic postamputation pain.

Management of Neuropathic Pain with Neurectomy Combined with Dermal Sensory Regenerative Peripheral Nerve Interface (DS-RPNI)

Neuropathic pain affects a large percentage of the U.S. population and leads to tremendous morbidity. Numerous nonsurgical and surgical treatments have been utilized to try and manage neuropathic pain with varying degrees of success. Recent research investigating ways to improve prosthetic control have identified new mechanisms for preventing neuromas in both motor and sensory nerves with free muscle and dermal grafts, respectively. These procedures have been used to treat chronic neuropathic pain in nonamputees, as well, in order to reduce failure rates found with traditional neurectomy procedures. Herein, we focus our attention on Dermal Sensory-Regenerative Peripheral Nerve Interfaces (DS-RPNI, free dermal grafts) which can be used to physiologically "cap" sensory nerves following neurectomy and have been shown to significantly decrease neuropathic pain.

Pain and Functional Outcomes following Targeted Muscle Reinnervation: A Systematic Review

BACKGROUND

It is estimated that by 2050, a total of 3.6 million patients will be living with an amputation in the United States. The objective of this systematic review is to evaluate the effect of targeted muscle reinnervation (TMR) on pain and physical functioning in amputees.

METHODS

A literature search was performed on PubMed, Embase, and MEDLINE up to November 28, 2021. Clinical studies assessing the outcomes of TMR (pain, prosthesis control, life quality, limb function, and disability) were included.

RESULTS

Thirty-nine articles were included. The total number of patients who underwent TMR was 449, and 716 were controls. Mean follow-up was 25 months. A total of 309 (66%) lower-limb and 159 (34%) upper-limb amputations took place in the TMR group, the most common being below-knee amputations (39%). The control group included a total of 557 (84%) lower-limb and 108 (16%) upper-limb amputations; the greatest proportion being below-knee amputations in this group as well (54%). Trauma was the most common indication for amputation. Phantom limb pain scores were lower by 10.2 points for intensity ( P = 0.01), 4.67 points for behavior ( P = 0.01), and 8.9 points for interference ( P = 0.09). Similarly, residual limb pain measures were lower for cases for intensity, behavior, and interference, but they failed to reach significance. Neuroma symptoms occurred less frequently, and functional and prosthesis control outcomes improved following TMR.

CONCLUSION

The literature evidence suggests that TMR is a promising therapy for improving pain, prosthesis use, and functional outcomes after limb amputation.

Regenerative Peripheral Nerve Interface Surgery for the Management of Chronic Posttraumatic Neuropathic Pain

Chronic pain resulting from peripheral nerve injury remains a common issue in the United States and affects 7 to 10% of the population. Regenerative Peripheral Nerve Interface (RPNI) surgery is an innovative surgical procedure designed to treat posttraumatic neuropathic pain, particularly when a symptomatic neuroma is present on clinical exam. RPNI surgery involves implantation of a transected peripheral nerve into an autologous free muscle graft to provide denervated targets to regenerating axons. RPNI surgery has been found in animal and human studies to be highly effective in addressing postamputation pain. While most studies have reported its uses in the amputation patient population for the treatment of neuroma and phantom limb pain, RPNI surgery has recently been used to address refractory headache, postmastectomy pain, and painful donor sites from the harvest of neurotized flaps. This review summarizes the current understanding of RPNI surgery for the treatment of chronic neuropathic pain.

Neuropathic pain of the superficial branch of the radial nerve - Factors influencing surgical outcome and patient satisfaction

BACKGROUND

Due to its partially superficial course, the superficial branch of the radial nerve is vulnerable to injury by trauma or surgery, potentially leading to painful neuroma. Surgical treatment is difficult. Among other factors, smoking and duration of pain before revision surgery have been suggested as risk factors for persistent pain after surgical revision, without concrete evidence. The aim of this study was therefore to identify factors influencing the outcome of revision surgery in SBRN neuropathic pain in our department.

METHODS

All 51 patients receiving revision surgery of the superficial branch of the radial nerve for neuropathic pain from 2010 to 2020 were contacted; 19 agreed to return for assessment. A medical chart review was performed to collect patient-, pain- and treatment-specific factors. Outcomes were recorded. In an outpatient consultation, clinical follow-up was performed and patients filled out the DASH, MHQ and painDETECT questionnaires.

RESULTS

After revision surgery, all patients experienced persistent pain. On multivariate logistic regression evaluating the risk of persistent pain, only smoking emerged as an independent risk factor. Age, gender, dominant side, location, time between trigger and surgery or diagnosis did not emerge as risk factors. No predictor for successful return to work could be identified.

CONCLUSIONS

Treatment of painful neuroma of the superficial branch of the radial nerve is a challenge. Patients with neuropathic pain should be coached toward smoking cessation before neuroma surgery. Surgery can show benefit even after long symptom duration. No correlations between study clinical variables or test results and return to work could be identified, suggesting that other factors play a role in return to work.

Surgery for mononeuropathies

Advancement in microsurgical techniques and innovative approaches including greater use of nerve and tendon transfers have resulted in better peripheral nerve injury (PNI) surgical outcomes. Clinical evaluation of the patient and their injury factors along with a shift toward earlier time frame for intervention remain key. A better understanding of the pathophysiology and biology involved in PNI and specifically mononeuropathies along with advances in ultrasound and magnetic resonance imaging allow us, nowadays, to provide our patients with a logical and sophisticated approach. While functional outcomes are constantly being refined through different surgical techniques, basic scientific concepts are being advanced and translated to clinical practice on a continuous basis. Finally, a combination of nerve transfers and technological advances in nerve/brain and machine interfaces are expanding the scope of nerve surgery to help patients with amputations, spinal cord, and brain lesions.

Nerve Capping Techniques for Neuroma Management: A Comprehensive Literature Review

BACKGROUND/AIM OF THE STUDY

Nerve capping is a method of neuroma treatment or prevention that consists of the transplantation of a proximal nerve stump into an autograft or other material cap, after surgical removal of the neuroma or transection of the nerve. The aim was to reduce neuroma formation and symptoms by preventing neuronal adhesions and scar tissue. In this narrative literature review, we summarize the studies that have investigated the effectiveness of nerve capping for neuroma management to provide clarity and update the clinician's knowledge on the topic.

METHODS

A systematic electronic search following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria was performed in the PubMed database combining "neuroma," "nerve," "capping," "conduit," "treatment," "management," "wrap," "tube," and "surgery" as search terms. English-language clinical studies on humans and animals that described nerve capping as a treatment/prevention technique for neuromas were then selected based on a full-text article review. The data from the included studies were compiled based on the technique and material used for nerve capping, and technique and outcomes were reviewed.

RESULTS

We found 10 applicable human studies from our literature search. Several capping materials were described: epineurium, nerve, muscle, collagen nerve conduit, Neurocap (synthetic copolymer of lactide and caprolactone, which is biocompatible and resorbable), silicone rubber, and collagen. Overall, 146 patients were treated in the clinical studies. After surgery, many patients were completely pain-free or had considerable improvement in pain scores, whereas some patients did not have improvement or were not satisfied after the procedure. Nerve capping was used in 18 preclinical animal studies, using a variety of capping materials including autologous tissues, silicone, and synthetic nanofibers. Preclinical studies demonstrated successful reduction in rates of neuroma formation.

CONCLUSIONS

Nerve capping has undergone major advancements since its beginnings and is now a useful option for the treatment or prevention of neuromas. As knowledge of peripheral nerve injuries and neuroma prevention grows, the criterion standard neuroprotective material for enhancement of nerve regeneration can be identified and applied to produce reliable surgical outcomes.

TMR for Peripheral Sensory Nerve Neuroma around the Wrist Utilizing the Distal Anterior Interosseous Nerve

Injury to the peripheral sensory nerves of the hand and wrist is common and can lead to debilitating neuromas and significantly impair patients' quality of life. Target-muscle reinnervation (TMR) is a novel method for treating neuromas that can result in significant clinical improvement. However, TMR for the peripheral sensory nerves in the hand and wrist is restricted by the limited options for motor branches. The adaptability of the anterior interosseous nerve (AIN) as a target for TMR treating peripheral sensory neuroma has not been thoroughly investigated or implemented therapeutically. This study aimed to evaluate the use of AIN as a viable recipient of TMR for treating peripheral sensory neuromas around the wrist. In this retrospective study, eight patients were included over 18 months from June 2021 to January 2023 at Hamad Medical Corporation. The average follow-up time after TMR was 13 months. The peripheral sensory nerves involved were the radial sensory nerve in five cases, the palmar cutaneous branch of the median nerve in one case, and the median nerve in one case. The preoperative average VAS pain score was 7 of 10 compared with the postoperative pain score of 2 of 10. In conclusion, the AIN can be used as a first-choice motor target for all peripheral sensory neuromas around the wrist for the following reasons: first, it can be reached by the peripheral sensory nerves around the wrist; second, the pronator quadratus muscle is expandable; and third, the AIN can be taken with a long proximal tail for flexible coaptation with the peripheral sensory nerves.

Google Trends Analysis of Peripheral Nerve Disease and Surgery

BACKGROUND

Despite advances in the surgical management of peripheral nerve pathologies over the past several decades, it is unknown how public awareness of these procedures has changed. We hypothesize that Google searches for peripheral nerve surgery have increased over time.

METHODS

Google Trends was queried for search volumes of a list of 40 keywords related to the following topics in peripheral nerve surgery: spasticity, nerve injury, prosthetics, and nerve pain. Monthly relative search volume over the first 5 years of the study period (2010-2014) was compared with that of the last 5 years (2018-2022) of the study period.

RESULTS

Search volumes for keywords "nerve injury," "nerve laceration," "peripheral nerve injury," "nerve repair," "nerve transfer", "neuroma," "neuroma pain," "nerve pain," "nerve pain surgery," and "neuroma pain surgery" all increased more than 10% points in relative search volume over the study period (P < 0.0001 for each keyword). In contrast, searches for "rhizotomy," "spasticity surgery," "targeted muscle reinnervation," "bionic arm," and "myoelectric prosthesis" either decreased or remained stable. Technical terms such as "selective neurectomy," "hyperselective neurectomy," "regenerative peripheral nerve interface," and "regenerative peripheral nerve interface surgery" did not have adequate search volume to be reported by Google Trends.

CONCLUSIONS

The increase in Google searches related to nerve injury and pain between 2010 and 2022 may reflect increasing public recognition of these clinical entities and surgical techniques addressing them. Technical terms relating to nerve pain are infrequently searched, surgeons should use plain English terms for online discovery. Interest in spasticity and myoelectric prosthetics remains stable, indicating an opportunity for better public outreach.

Improving outcomes in traumatic peripheral nerve injuries to the upper extremity

Peripheral nerve lesions of the upper extremity are common and are associated with devastating limitations for the patient. Rapid and accurate diagnosis of the lesion by electroneurography, neurosonography, or even MR neurography is important for treatment planning. There are different therapeutic approaches, which may show individual differences depending on the injured nerve. If a primary nerve repair is not possible, several strategies exist to bridge the gap. These may include autologous nerve grafts, bioartificial nerve conduits, or acellular nerve allografts. Tendon and nerve transfers are also of major importance in the treatment of nerve lesions in particular with long regeneration distances. As a secondary reconstruction, in addition to tendon transfers, there is also the option for free functional muscle transfer. In amputations, the prevention of neuroma is of great importance, for which different strategies exist, such as target muscle reinnervation, regenerative peripheral nerve interface, or neurotized flaps. In this article, we give an overview of the latest methods for the therapy of peripheral nerve lesions.

Patient reported symptoms and disabilities before and after neuroma surgery: a register-based study

Residual problems may occur from neuroma despite surgery. In a 12-month follow-up study using national register data, symptoms, and disabilities related to surgical methods and sex were evaluated in patients surgically treated for a neuroma. Among 196 identified patients (55% men; lower age; preoperative response rate 20%), neurolysis for nerve tethering/scar formation was the most used surgical method (41%; more frequent in women) irrespective of affected nerve. Similar preoperative symptoms were seen in patients, where different surgical methods were performed. Pain on load was the dominating symptom preoperatively. Women scored higher preoperatively at pain on motion without load, weakness and QuickDASH. Pain on load and numbness/tingling in fingers transiently improved. The ability to perform daily activities was better after nerve repair/reconstruction/transposition than after neurolysis. Regression analysis, adjusted for age, sex, and affected nerve, showed no association between surgical method and pain on load, tingling/numbness in fingers, or ability to perform daily activities. Neuroma, despite surgery, causes residual problems, affecting daily life. Choice of surgical method is not strongly related to pre- or postoperative symptoms. Neurolysis has similar outcome as other surgical methods. Women have more preoperative symptoms and disabilities than men. Future research would benefit from a neuroma-specific ICD-code, leading to a more precise identification of patients.

Lower extremity peripheral nerve pathology: Utility of preoperative ultrasound-guided needle localization before operative intervention

Historically, the use of ultrasound (US) in the management of peripheral nervous system (PNS) pathology has been limited to diagnostic confirmation or guidance for interventional injections. This technical case series will demonstrate the utility and versatility of preoperative US-guided needle localization for the excision of lower extremity neuromas and other pathology of the PNS. Five patients with symptomatic lower extremity PNS tumors were retrospectively reviewed. This case series corroborates the technical nuances of localizing lower extremity neuromas by US-guided needle and wire placement prior to operative excision. This was achieved by a multidisciplinary team that included plastic surgery, neurosurgery, and radiology. Five patients had US-guided needle localization of a lower extremity PNS target prior to operative intervention. Three patients had lower extremity neuromas of varying origins, including the lateral femoral cutaneous nerve (LFCN), saphenous nerve, and sural nerve. The remaining two patients had a sciatic nerve sheath Schwannoma and a femoral nerve glomus tumor. Under sonographic visualization, a needle was advanced to the target perimeter and withdrawn, leaving behind a percutaneous guidewire. This technique simplified the marking of the nerve course prior to dissection and led to efficient intraoperative identification of all five PNS tumors without any complications. Preoperative US-guided needle localization led to safe, accurate, and efficient perioperative and intraoperative identification of neuromas and other PNS tumors of the lower extremity prior to excision. By reducing the challenges of nerve identification in a scarred tissue bed, this multidisciplinary approach may decrease postoperative patient morbidity.

Long-term tactile hypersensitivity after nerve crush injury in mice is characterized by the persistence of intact sensory axons

ABSTRACT

Traumatic peripheral nerve injuries are at high risk of neuropathic pain for which novel effective therapies are urgently needed. Preclinical models of neuropathic pain typically involve irreversible ligation and/or nerve transection (neurotmesis). However, translation of findings to the clinic has so far been unsuccessful, raising questions on injury model validity and clinically relevance. Traumatic nerve injuries seen in the clinic commonly result in axonotmesis (ie, crush), yet the neuropathic phenotype of "painful" nerve crush injuries remains poorly understood. We report the neuropathology and sensory symptoms of a focal nerve crush injury using custom-modified hemostats resulting in either complete ("full") or incomplete ("partial") axonotmesis in adult mice. Assays of thermal and mechanically evoked pain-like behavior were paralleled by transmission electron microscopy, immunohistochemistry, and anatomical tracing of the peripheral nerve. In both crush models, motor function was equally affected early after injury; by contrast, partial crush of the nerve resulted in the early return of pinprick sensitivity, followed by a transient thermal and chronic tactile hypersensitivity of the affected hind paw, which was not observed after a full crush injury. The partially crushed nerve was characterized by the sparing of small-diameter myelinated axons and intraepidermal nerve fibers, fewer dorsal root ganglia expressing the injury marker activating transcription factor 3, and lower serum levels of neurofilament light chain. By day 30, axons showed signs of reduced myelin thickness. In summary, the escape of small-diameter axons from Wallerian degeneration is likely a determinant of chronic pain pathophysiology distinct from the general response to complete nerve injury.

Revision Surgery for Recurrent Morton Neuroma with Use of a Collagen Conduit

Background

Painful neuromas of the foot and ankle frequently pose a treatment dilemma because of persistent pain or recurrence after resection. Primary surgical treatment of painful neuromas includes simple excision with retraction of the residual nerve ending to a less vulnerable location1-4. The use of a collagen conduit for recurrent neuromas is advantageous, particularly in areas with minimal soft-tissue coverage options, and is a technique that has shown 85% patient satisfaction regarding surgical outcomes7. Additionally, the use of a collagen conduit limits the need for deep soft-tissue dissection and reduces the morbidity typically associated with nerve burial.

Description

Specific steps include appropriate physical examination, preoperative planning, and supine patient positioning. The patient is placed supine with a lower-extremity bolster under the ipsilateral extremity in order to allow improved visualization of the plantar surface of the foot. A nonsterile tourniquet is placed on the thigh. The incision site is marked out, and a longitudinal plantar incision is made until proximal healthy nerve is identified-typically approximately 1 to 2 cm, but the incision can be extended up to 6 cm. The incision is made between the metatarsals, with blunt dissection carried down to the neuroma. The neuroma is sharply excised distally through healthy nerve, and a whip stitch is placed to facilitate the collagen conduit placement. The collagen conduit is passed dorsally into the intermetatarsal space and secured to the dorsal fascia of the foot. The wound is closed with 3-0 nylon horizontal mattress sutures. Postoperatively, a soft dressing is applied to the operative extremity, and patients are advised to be non-weight-bearing for two weeks. At two weeks, patients begin partial weight-bearing with use of a boot, and physical therapy is initiated. No antibiotics are necessary, and 300 mg of gabapentin is prescribed and tapered off by the six-week follow-up visit. Follow-ups are conducted at 2, 6, 12, 24, and fifty-two weeks. It is necessary to monitor for signs and symptoms of infection, surgical complications, and neuroma recurrence during follow-up appointments.

Alternatives

Simple excision of the neuroma with proximal burial into muscle or bone is a common surgical technique. However, inadequate resection of the nerve or poor surgical technique can lead to recurrent neuromas. For neuromas not responding to simple excision, other techniques have been utilized, including cauterization, chemical agents, nerve capping, and muscle or bone burial5,6. The results of these techniques have varied, and none has gained clinical superiority over the other6.

Rationale

A study analyzing the use of collagen conduits for painful neuromas of the foot and ankle has shown this technique to be a safe and successful alternative to the previously discussed methods of resection7. That study by Gould et al. found that 85% of patients had a substantial reduction in pain, with mean visual analog scale (VAS) pain scores reducing from 8 to 10 preoperatively to 0 to 4 postoperatively7. Moreover, alternative biological conduits, such as the greater saphenous vein, have proven to be costly in time and resources, as this structure is often utilized in cardiovascular bypass surgery and its harvest conveys a risk of iatrogenic nerve injury to the patient7.Numerous studies focusing on excision of recurrent Morton neuromas via a plantar approach have found variable success rates. Of the patients surveyed in those studies, 75% reported substantial pain improvement. However, <50% of these queried patients reported complete pain relief8,9. Studies analyzing the dorsal approach for revision Morton neuroma excision found similar success rates. Approximately 78% of patients reported good or excellent postoperative outcomes, and significant improvements were observed in patient postoperative Patient-Reported Outcomes Measurement Information System (PROMIS) scores for pain interference, intensity, and global physical health10,11. One study comparing outcomes following plantar versus dorsal approaches for recurrent Morton neuroma found no significant difference in postoperative patient outcomes. That study suggested that surgeons utilize the approach with which they are most comfortable12. Gould et al. reported an 85% success rate with collagen conduit, which was similar to if not slightly improved compared with the other prior studies. The utilization of a collagen conduit technique thus offers comparable patient outcomes for patients with difficult neuromas7.

Expected Outcomes

Recurrent neuroma resection with the use of a collagen conduit has proven to provide satisfactory patient outcomes regarding pain and neuritis symptoms7. The goal of any neuroma resection is to greatly diminish or entirely eliminate nerve pain. Based on the available evidence, there has been no proven clinical superiority of any particular technique over the others6. However, in the present example case, the location of the patient's neuroma in this video makes it 85% likely that the patient will report satisfactory outcomes and 50% likely that the patient will be entirely symptom-free7. At two weeks postoperatively, the patient reported well controlled pain, absence of burning or tingling sensation, full range of movement in the foot, and intact sensation throughout all major nerve distributions, including the saphenous; superficial peroneal nerve; deep peroneal nerve; and sural, medial, and lateral plantar nerves. However, sensation is absent distal to the site of a neuroma resection.

Important Tips

Careful preoperative planting is of utmost importance.Ruling out other potential pathologies is necessary to ensure proper outcomes.Meticulous dissection should be carried out, with delicate handling of the proximal nerve ending.Excision of the nerve should be done sharply through the healthy portion of the nerve.Appropriate sizing of the nerve conduit (with a commercially available industry sizer) should be performed.The nerve conduit should be passed dorsally and secured to the dorsal fascia without any tension.

Acronyms and Abbreviations

MRI = magnetic resonance imagingUS = ultrasoundVAS = visual analog scale.

Post-traumatic radial nerve neuroma: A case report

Introduction

Radial nerve neuromas (RNNs) are mostly post-traumatic conditions that occur after a complete or partial section of a nerve. Here we report a case of post-traumatic RNN with good functional progression after intense physical rehabilitation.

Case presentation

A 49 years old patient with a post-complete section of the radial nerve underwent intensive physical rehabilitation with two sessions of ultrasound-guided injections of 10 % glucose saline around the neuroma. 12 months later, the patient improved his wrist and hand finger extension functions.

Conclusion

Several surgical and non-surgical therapies have been proposed for the treatment of neuromas. However, no consensus currently exists, and management is frequently adapted to each patient.

Surgical Treatment of Symptomatic End-Neuroma With a New Bioresorbable Copolyester Nerve Capping Device: A Multicenter Prospective Cohort Study

BACKGROUND

Neuroma-induced neuropathic pain is associated with loss of function and reduced quality of life. No consistently effective standard-of-care treatment has been defined. Neurocap, a bioresorbable nerve capping device, has been designed to isolate the nerve stump from surrounding tissues to reduce development of symptomatic end-neuromas.

METHODS

Patients with peripheral symptomatic end-neuromas were included in a prospective, multicenter, single-arm design. Data were collected presurgery up till 24 months postsurgery. Eligible patients with neuromas were identified based on blocks using anesthetic. Intervention included surgical excision and capping of the transected proximal nerve end with the Neurocap. Main outcome measures were pain, function, recurrence of symptomatic neuroma, use of analgesics, and adverse events.

RESULTS

In total, 73 patients with 50 upper-extremity and 23 lower-extremity end-neuromas were enrolled. End-neuromas were predominately located in the digits and lower leg. Statistical power of the study outcomes was preserved by 46 of 73 patients completing 24-month follow-up. The mean VAS-Pain score at baseline was 70.2 ± 17.8 (scale 0-100) and decreased significantly to 31 ± 32.5 (P < 0.001). Function significantly improved over time. The recurrence rate of confirmed symptomatic neuroma was low (2 of 98 capped nerves). Adverse event rate was low and included pain and infection; there were no unexpected device-related adverse events. Most patients reported lower use of nonsteroidal anti-inflammatory drugs, opioids, and antineuropathic medications at last follow-up compared with baseline.

CONCLUSIONS

End-neuroma treatment with excision and capping resulted in long-term significant reduction in reported pain, disability, and analgesic medication use. Adverse event rate was low.

Regenerative Peripheral Nerve Interface Surgery: Anatomic and Technical Guide

Regenerative peripheral nerve interface (RPNI) surgery has been demonstrated to be an effective tool as an interface for neuroprosthetics. Additionally, it has been shown to be a reproducible and reliable strategy for the active treatment and for prevention of neuromas. The purpose of this article is to provide a comprehensive review of RPNI surgery to demonstrate its simplicity and empower reconstructive surgeons to add this to their armamentarium. This article discusses the basic science of neuroma formation and prevention, as well as the theory of RPNI. An anatomic review and discussion of surgical technique for each level of amputation and considerations for other etiologies of traumatic neuromas are included. Lastly, the authors discuss the future of RPNI surgery and compare this with other active techniques for the treatment of neuromas.

Neuroma Treatment With the Acellular Nerve Allograft Reconstruction Technique

Treatment of a painful neuroma is a challenging problem for both the patient and the providers. Current surgical treatment options typically include excision of the neuroma and stump relation. However, with both treatment options, patients have high rates of persistent pain and rates of neuroma recurrence. We describe two patients with neuromas treated with our acellular nerve allograft reconstruction technique. This technique involves the excision of the neuroma and bridging the proximal nerve end to the surrounding tissue with an acellular nerve allograft. Both patients had immediate resolution of their neuropathic pain that was maintained at their final follow-up. Acellular nerve allograft reconstruction is a promising treatment option for the treatment of painful neuromas.

Outcomes of Surgical Treatment of Peripheral Neuromas of the Hand and Forearm

The choice of a specific technique for surgical treatment of neuromas remains a problem. The purpose of this study is to determine the overall effectiveness of surgery as well as to find out whether certain surgical procedures are more effective than others. Twenty-nine patients operated between 1998 and 2018 and followed for at least 12 months were reviewed. Clinical assessment included the identification of a pre- and postoperative Tinel sign, pain visual analog score, two-point discrimination (2PD), and grip strength. Mechanisms of injury included clean lacerations (11), crush injuries (11), and other trauma or surgery (7). Mean time from presentation to surgery was 9 months. Seven surgical procedures involving excision in 10 patients and excision and nerve repair in 19 patients were performed. Pain score improved from an average of 7.1 ± 2.3 to 1.8 ± 1.7 with 27 patients (93%) reporting mild or no postoperative pain. Nine patients complained of residual scar hypersensitivity and six patients had residual positive Tinel. No patient required an additional surgical procedure. 2PD improved from an average of 9.6 ± 4.0 to 6.8 ± 1.0. The improvement of pain score and 2PD was statistically significant. Nerve repair resulted in marginally better outcomes, in terms of 2PD and grip strength recovery, than excision alone. The mechanism of injury, zone of involvement, time to intervention, or length of follow-up did not have an impact on the outcomes. Although patient numbers in this study are large in comparison to previous studies, larger patient numbers will allow for a multivariate analysis, which can be possible with a prospective multicenter trial.

A Consensus Approach for Targeted Muscle Reinnervation in Amputees

Amputations have been performed with few modifications since the dawn of surgery. Blood vessels are ligated, bones are shortened, and nerves are cut. In a percentage of people, this can result in severe neuropathic, residual limb, and phantom limb pain. Targeted muscle reinnervation is a surgical procedure initially conceived to optimize function for myoelectric prostheses in amputees. Recently, it has been adopted more widely by surgeons for the prevention and treatment of neuropathic pain. Perhaps as a function of its relatively recent development, many authors perform this operation differently, and there has been no overall agreement regarding the principles, indications, technical specifics, and postoperative management guidelines. This article is written as a consensus statement by surgeons focused on the treatment of neuropathic pain and those with extensive experience performing targeted muscle reinnervation. It is designed to serve as a roadmap and template for extremity surgeons to consider when performing targeted muscle reinnervation.

Preventive Effect of Local Lidocaine Administration on the Formation of Traumatic Neuroma

BACKGROUND

Traumatic neuroma is a common sequela of peripheral nerve injury or amputation, which often leads to severe neuropathic pain. The present study investigated the effect of local lidocaine administration on preventing the formation of traumatic neuroma.

METHODS

Forty-eight male Sprague-Dawley rats were randomly assigned to two groups. The lidocaine group underwent sciatic nerve transection, followed by an injection of lidocaine (0.5%) around the proximal of a severed sciatic nerve under ultrasound-guidance 2-7 days after neurectomy. In the control group, rats received an injection of saline following neurectomy. The autotomy score, mechanical allodynia, thermal hyperalgesia, histological assessment, expression of neuroma, and pain-related markers were detected.

RESULTS

Lidocaine treatment reduced the autotomy score and attenuated mechanical allodynia and thermal hyperalgesia. The mRNA expression of α-SMA, NGF, TNF-α, and IL-1β all significantly decreased in the lidocaine group in comparison to those in the saline control group. The histological results showed nerve fibers, demyelination, and collagen hyperplasia in the proximal nerve stump in the saline control group, which were significantly inhibited in the lidocaine group.

CONCLUSIONS

The present study demonstrated that local lidocaine administration could inhibit the formation of painful neuroma due to traumatic nerve injury.

Reporting guidelines for surgical technique could be improved: a scoping review and a call for action

OBJECTIVES

To identify reporting guidelines related to surgical technique and propose recommendations for areas that require improvement.

STUDY DESIGN AND SETTING

A protocol-guided scoping review was conducted. A literature search of MEDLINE, the EQUATOR Network Library, Google Scholar, and Networked Digital Library of Theses and Dissertations was conducted to identify surgical technique reporting guidelines published up to December 31, 2021.

RESULTS

We finally included 55 surgical technique reporting guidelines, vascular surgery (n = 18, 32.7%) was the most common among the clinical specialties covered. The included guidelines generally showed a low degree of international and multidisciplinary cooperation. Few guidelines provided a detailed development process (n = 14, 25.5%), conducted a systematic literature review (n = 13, 23.6%), used the Delphi method (n = 4, 7.3%), or described post-publication strategy (n = 6, 10.9%). The vast majority guidelines focused on the reporting of intraoperative period (n = 50, 90.9%). However, of the guidelines requiring detailed descriptions of surgical technique methodology (n = 43, 78.2%), most failed to provide guidance on what constitutes an adequate description.

CONCLUSION

Our study demonstrates significant deficiencies in the development methodology and practicality of reporting guidelines for surgical technique. A standardized reporting guideline that is developed rigorously and focuses on details of surgical technique may serve as a necessary impetus for change.

The Neuroma Startle Sign: A Surgical Indicator of Proximity to an Injured Nerve

During operative intervention for the treatment of symptomatic neuromas, the authors have observed a hypersensitive "startle" response to stimulation in proximity to the painful nerve. This physiologic sign is an indicator of the specific anatomic localization of the painful stimulus, commonly a symptomatic neuroma, that appears to be reproducible. The aim of this article is to describe this "neuroma startle sign," posit the underlying mechanism for this observation, and propose how this phenomenon could be clinically harnessed for innovation and optimization in both surgery and anesthesia for more effective symptomatic neuroma localization.

Hopeless Neuroma-The Neurotized Free Flap Tissue Augmentation as Salvage Therapy-A Concept and Clinical Demonstration

Therapy-resistant neuroma pain is a devastating condition for patients and surgeons. Although various methods are described to surgically deal with neuromas, some discontinuity and stump neuroma therapies have anatomical limitations. It is widely known that a neurotizable target for axon ingrowth is beneficial for dealing with neuromas. The nerve needs "something to do". Furthermore, sufficient soft tissue coverage plays a major role in sufficient neuroma therapy. We aimed, therefore, to demonstrate our approach for therapy of resistant neuromas with insufficient tissue coverage using free flaps, which are sensory neurotized via anatomical constant branches. The central idea is to provide a new target, a new "to do" for the painful mislead axons, as well as an augmentation of deficient soft tissues. As indication is key, we furthermore demonstrate clinical cases and common neurotizable workhorse flaps.

Resurgent neuropathic discharge: an obstacle to the therapeutic use of neuroma resection?

ABSTRACT

Ectopic discharge ("ectopia") in damaged afferent axons is a major contributor to chronic neuropathic pain. Clinical opinion discourages surgical resection of nerves proximal to the original injury site for fear of resurgence of ectopia and exacerbated pain. We tested this concept in a well-established animal neuroma model. Teased-fiber recordings were made of ectopic spontaneous discharge originating in the experimental nerve-end neuroma and associated dorsal root ganglia in rats that underwent either a single transection (with ligation) of the sciatic nerve or 2 consecutive transections separated by 7, 14, 21, or 30 days. Ectopia emerged in afferent A and C fibers after a single cut with kinetics anticipated from previous studies. When resection was performed during the early period of intense A-fiber activity, a brief period of resurgence was observed. However, resection of neuromas of more than 14 days was followed by low levels of activity with no indication of resurgence. This remained the case in trials out to 60 days after the first cut. Similarly, we saw no indication of resurgent ectopia originating in axotomized dorsal root ganglion neuronal somata and no behavioral reflection of resurgence. In summary, we failed to validate the concern that proximal resection of a problematic nerve would lead to intense resurgent ectopic discharge and pain. As the well-entrenched concept of resurgence is based more on case reports and anecdotes than on solid evidence, it may be justified to relax the stricture against resecting neuromas as a therapeutic strategy, at least within the framework of controlled clinical trials.

Percutaneous treatments for residual and/or phantom limb pain in adults with lower-extremity amputations: A narrative review

Residual limb pain (RLP) and phantom limb pain (PLP) profoundly affect the lives of many individuals who have undergone lower- or upper-extremity amputation. Despite the considerable impact of RLP/PLP on quality of life in persons with amputation, there have been few attempts to evaluate the efficacy of percutaneous interventions in the treatment of RLP and/or PLP. This narrative review evaluates the effectiveness of percutaneous treatments for RLP and/or PLP in patients after lower-extremity amputation. Peripheral nerve stimulation, alcohol neurolysis, conventional thermal radiofrequency ablation, perineural corticosteroid injection, botulinum toxin injection, and etanercept injection were associated with varying success rates. Wide confidence intervals and small treatment cohorts impede assessments of overall success. High-quality studies of nonsurgical, percutaneous treatments for RLP and/or PLP are lacking. Well-designed randomized controlled trials and large cohort studies with comparison groups using validated outcomes are needed to determine the effectiveness of nonsurgical interventions for the treatment of RLP and PLP.

Traumatic neuromas of peripheral nerves: Diagnosis, management and future perspectives

Traumatic neuromas are infrequent in clinical settings but are prevalent following trauma or surgery. A traumatic neuroma is not a true malignancy, rather, it is a hyperplastic, reparative nerve reaction after injury and typically manifests as a nodular mass. The most common clinical manifestations include painful hypersensitivity and the presence of a trigger point that causes neuralgic pain, which could seriously decrease the living standards of patients. While various studies are conducted aiming to improve current diagnosis and management strategies via the induction of emerging imaging tools and surgical or conservative treatment. However, researchers and clinicians have yet to reach a consensus regarding traumatic neuromas. In this review, we aim to start with the possible underlying mechanisms of traumatic neuromas, elaborate on the diagnosis, treatment, and prevention schemes, and discuss the current experiment models and advances in research for the future management of traumatic neuromas.

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.

Chronic pain and local pain in usually painless conditions including neuroma may be due to compressive proximal neural lesion

It has been unexplained why chronic pain does not invariably accompany chronic pain-prone disorders. This question-driven, hypothesis-based article suggests that the reason may be varying occurrence of concomitant peripheral compressive proximal neural lesion (cPNL), e.g., radiculopathy and entrapment plexopathies. Transition of acute to chronic pain may involve development or aggravation of cPNL. Nociceptive hypersensitivity induced and/or maintained by cPNL may be responsible for all types of general chronic pain as well as for pain in isolated tissue conditions that are usually painless, e.g., neuroma, scar, and Dupuytren's fibromatosis. Compressive PNL induces focal neuroinflammation, which can maintain dorsal root ganglion neuron (DRGn) hyperexcitability (i.e., peripheral sensitization) and thus fuel central sensitization (i.e., hyperexcitability of central nociceptive pathways) and a vicious cycle of chronic pain. DRGn hyperexcitability and cPNL may reciprocally maintain each other, because cPNL can result from reflexive myospasm-induced myofascial tension, muscle weakness, and consequent muscle imbalance- and/or pain-provoked compensatory overuse. Because of pain and motor fiber damage, cPNL can worsen the causative musculoskeletal dysfunction, which further accounts for the reciprocity between the latter two factors. Sensitization increases nerve vulnerability and thus catalyzes this cycle. Because of these mechanisms and relatively greater number of neurons involved, cPNL is more likely to maintain DRGn hyperexcitability in comparison to distal neural and non-neural lesions. Compressive PNL is associated with restricted neural mobility. Intermittent (dynamic) nature of cPNL may be essential in chronic pain, because healed (i.e., fibrotic) lesions are physiologically silent and, consequently, cannot provide nociceptive input. Not all patients may be equally susceptible to develop cPNL, because occurrence of cPNL may vary as vary patients' predisposition to musculoskeletal impairment. Sensitization is accompanied by pressure pain threshold decrease and consequent mechanical allodynia and hyperalgesia, which can cause unusual local pain via natural pressure exerted by space occupying lesions or by their examination. Worsening of local pain is similarly explainable. Neuroma pain may be due to cPNL-induced axonal mechanical sensitivity and hypersensitivity of the nociceptive nervi nervorum of the nerve trunk and its stump. Intermittence and symptomatic complexity of cPNL may be the cause of frequent misdiagnosis of chronic pain.

A cohort study on neuropathic pain of the saphenous nerve—factors influencing surgical outcome

Background

Due to its partially superficial course, the saphenous nerve is vulnerable to injury by trauma or surgery potentially leading to painful neuroma formation. Different surgical techniques to treat neuroma have been described, but so far, no one has proven to be superior to the others. The aim of this study was therefore to identify factors influencing the outcome of revision surgery in saphenous nerve neuropathic pain in our department.

Methods

From 2010 to 2020, a total of 29 consecutive patients with neuropathic pain and suspected neuroma of the saphenous nerve underwent revision surgery. A medical chart review was performed to collect patient-, pain-, and treatment-specific factors. Outcomes were registered.

Results

Post revision surgery in neuropathic pain of the saphenous nerve, 16 (55.2%) patients suffered from persisting pain. In multivariable logistic regression models evaluating the risk of persisting pain post saphenous nerve revision surgery, both smoking and preoperative opiate consumption represented independent predictors of higher risk for persisting pain.

Conclusions

Patients with injury to the saphenous nerve should be coached toward smoking cessation. Whenever possible, forgoing opiate treatment might be beneficial.

Level of evidence: Level IV, Risk/Prognostic.

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.

Controlling axonal regeneration with acellular nerve allograft limits neuroma formation in peripheral nerve transection: An experimental study in a swine model

BACKGROUND

Symptomatic neuromata are a common indication for revision surgery following amputation. Previously described treatments, including traction neurectomy, nerve transposition, targeted muscle re-innervation, and nerve capping, have provided inconsistent results or are technically challenging. Prior research using acellular nerve allografts (ANA) has shown controlled termination of axonal regrowth in long grafts. The purpose of this study was to determine the ability of a long ANA to prevent neuroma formation following transection of a peripheral nerve in a swine model.

MATERIALS AND METHODS

Twenty-two adult female Yucatan miniature swine (Sus scrofa; 4-6 months, 15-25 kg) were assigned to control (ulnar nerve transection only, n = 10), treatment (ulnar transection and coaptation of 50 mm ANA, n = 10), or donor (n = 2) groups. Nerves harvested from donor group animals were treated to create the ANA. After 20 weeks, the transected nerves including any neuroma or graft were harvested. Both qualitative (nerve architecture, axonal sprouting) and quantitative histologic analyses (myelinated axon number, cross sectional area of nerve tissue) were performed.

RESULTS

Qualitative histologic analysis of control specimens revealed robust axon growth into dense scar tissue. In contrast, the treatment group revealed dwindling axons in the terminal tissue, consistent with attenuated neuroma formation. Quantitative analysis revealed a significantly decreased number of myelinated axons in the treatment group (1232 ± 540) compared to the control group (44,380 ± 7204) (p < .0001). Cross sectional area of nerve tissue was significantly smaller in treatment group (2.83 ± 1.53 mm² ) compared to the control group (9.14 ± 1.19 mm² ) (p = .0012).

CONCLUSIONS

Aberrant axonal growth is controlled to termination with coaptation of a 50 mm ANA in a swine model of nerve injury. These early results suggest further investigation of this technique to prevent and/or treat neuroma formation.

Agents Used for Nerve Blocks and Neurolysis

The recognition of pain and the treatments used for it are vital for all practitioners. Many types of pain can be treated in a locoregional fashion, which has significant implications not just for any individual patient but for society as a whole. These treatments are most effective when performed in a minimally invasive, image-guided fashion. Interventional radiologists should play a central role in providing these lifestyle-limiting treatments. This article describes the medications most typically used for spinal and extra-axial treatments in the management of patients in pain.

Mechanosensitive Ion Channel TMEM63A Gangs Up with Local Macrophages to Modulate Chronic Post-amputation Pain

Post-amputation pain causes great suffering to amputees, but still no effective drugs are available due to its elusive mechanisms. Our previous clinical studies found that surgical removal or radiofrequency treatment of the neuroma at the axotomized nerve stump effectively relieves the phantom pain afflicting patients after amputation. This indicated an essential role of the residual nerve stump in the formation of chronic post-amputation pain (CPAP). However, the molecular mechanism by which the residual nerve stump or neuroma is involved and regulates CPAP is still a mystery. In this study, we found that nociceptors expressed the mechanosensitive ion channel TMEM63A and macrophages infiltrated into the dorsal root ganglion (DRG) neurons worked synergistically to promote CPAP. Histology and qRT-PCR showed that TMEM63A was mainly expressed in mechanical pain-producing non-peptidergic nociceptors in the DRG, and the expression of TMEM63A increased significantly both in the neuroma from amputated patients and the DRG in a mouse model of tibial nerve transfer (TNT). Behavioral tests showed that the mechanical, heat, and cold sensitivity were not affected in the Tmem63a^-/- mice in the naïve state, suggesting the basal pain was not affected. In the inflammatory and post-amputation state, the mechanical allodynia but not the heat hyperalgesia or cold allodynia was significantly decreased in Tmem63a^-/- mice. Further study showed that there was severe neuronal injury and macrophage infiltration in the DRG, tibial nerve, residual stump, and the neuroma-like structure of the TNT mouse model, Consistent with this, expression of the pro-inflammatory cytokines TNF-α, IL-6, and IL-1β all increased dramatically in the DRG. Interestingly, the deletion of Tmem63a significantly reduced the macrophage infiltration in the DRG but not in the tibial nerve stump. Furthermore, the ablation of macrophages significantly reduced both the expression of Tmem63a and the mechanical allodynia in the TNT mouse model, indicating an interaction between nociceptors and macrophages, and that these two factors gang up together to regulate the formation of CPAP. This provides a new insight into the mechanisms underlying CPAP and potential drug targets its treatment.

A Systematic Review and Meta-analysis on the Incidence of Patients With Lower-Limb Amputations Who Developed Symptomatic Neuromata in the Residual Limb

BACKGROUND

Neuromata developed after major extremity amputation can cause pain, limit the use of prosthetics, and negatively affect the quality of life. The frequency of postamputation neuroma varies widely. The objective of this study was to determine the incidence of patients who developed symptomatic neuromata after lower-limb amputation through a systematic review and meta-analysis.

METHODS

A systematic review of the literature was performed on 4 major databases. Studies that reported the incidence of symptomatic neuroma in lower-limb amputees were included. A meta-analysis was performed to calculate the pooled incidence of neuromata.

RESULTS

Thirteen studies consisting of 1329 patients were included in this meta-analysis. The reported incidence of patients who developed symptomatic neuromata ranged between 4% and 49%. The median duration of follow-up was 8.6 years (interquartile range, 2.0-17.4 years). The pooled percentage (95% confidence interval [CI]) of lower-limb amputees who developed symptomatic neuromata was 19% (12%-29%). In studies with a duration of follow-up at least 3 years, the pooled percentage (95% CI) of lower-limb amputees who developed symptomatic neuromata was 30% (22%-40%). In studies with a follow-up period of fewer than 3 years, the pooled percentage (95% CI) of neuroma incidence was 3% (2%-6%).

CONCLUSIONS

In summary, the overall incidence of patients who developed symptomatic neuromata was 19% or approximately 1 in 5 lower-limb amputees. Symptomatic neuromata are more commonly diagnosed when the follow-up period is longer than 3 years. These findings suggest that neuroma after amputation might be underestimated in studies with a short duration of follow-up.