Alteration of neuroma formation by manipulation of its microenvironment

Multidisciplinary strategies to treat painful mononeuropathies in the upper extremity: from lab to bedside

Neuropathic pain in the upper extremity is a serious problem, commonly involving relatively young patients. The pain causes loss of function and productivity, changes a patient's lifestyle and can progress into a chronic pain syndrome with secondary psychosocial co-morbidities. Treating patients with a painful mononeuropathy remains challenging, with a monodisciplinary approach often having limited treatment efficacy. This narrative review discusses how to deal with this challenge in the treatment of patients with peripheral nerve injury pain, addressing the four important pillars: (1) diagnosing a painful mononeuropathy; (2) clinical pain phenotyping; (3) personalized pain treatment; and (4) using a multidisciplinary team approach.

Superficial branch of the radial nerve regularly contains fibers from the lateral antebrachial cutaneous nerve: A role in neuroma treatment

BACKGROUND

Many surgical strategies aim to treat the symptomatic neuroma of the superficial branch of the radial nerve (SBRN). It is still difficult to treat despite many attempts to reveal a reason for surgical treatment failure. The lateral antebrachial cutaneous nerve (LACN) is known to overlap and communicate with SBRN. Our study aims to determine the frequency of spreading of LACN fibers into SBRN branches through a microscopic dissection to predict where and how often LACN fibers may be involved in SBRN neuroma.

METHODS

Eighty-seven cadaveric forearms were thoroughly dissected. The path of LACN fibers through the SBRN branching was ascertained using microscopic dissection. Distances between the interstyloid line and entry of LACN fibers into the SBRN and emerging and bifurcation points of the SBRN were measured.

RESULTS

The LACN fibers joined the SBRN at a mean distance of 1.7 ± 2.5 cm proximal to the interstyloid line. The SBRN contained fibers from the LACN in 62% of cases. Most commonly, there were LACN fibers within the SBRN's third branch (59%), but they were also observed within the first branch, the second branch, and their common trunk (21%, 9.2%, and 22%, respectively). The lowest rate of the LACN fibers was found within the SBRN trunk (6.9%).

CONCLUSION

The SBRN contains LACN fibers in almost 2/3 of the cases, therefore, the denervation of both nerves might be required to treat the neuroma. However, the method must be considered based on the particular clinical situation.

Similar rates of reoperation for neuroma after transtibial amputations with and without targeted muscle reinnervation

Objective

To compare the rates of revision surgery for symptomatic neuromas in patients undergoing primary transtibial amputations with and without targeted muscle reinnervation (TMR).

Design

Retrospective cohort study.

Setting

Level I trauma hospital and tertiary military medical center.

Patients/Participants

Adult patients undergoing transtibial amputations with and without TMR.

Intervention

Transtibial amputation with targeted muscle reinnervation.

Main Outcome Measurements

Reoperation for symptomatic neuroma.

Results

During the study period, there were 112 primary transtibial amputations performed, 29 with TMR and 83 without TMR. Over the same period, there were 51 revision transtibial amputations performed, including 23 (21%) in the patients undergoing primary transtibial amputation at the study institution. The most common indications for revision surgery were wound breakdown/dehiscence (42%, n = 25), followed by symptomatic neuroma 18% (n = 9/51) and infection/osteomyelitis (17%, n = 10) as the most common indications. However, of the patients undergoing primary amputation at the study's institution, there was no difference in reoperation rates for neuroma when comparing the TMR group (3.6%, n = 1/28) and no TMR group (4.0%, n = 3/75) (P = 0.97).

Conclusions

Symptomatic neuroma is one of the most common reasons for revision amputation; however, this study was unable to demonstrate a difference in revision surgery rates for neuroma for patients undergoing primary transtibial amputation with or without targeted muscle reinnervation.

Level of Evidence

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

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.

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.

The Use of Nerve Caps after Nerve Transection in Headache Surgery: Cadaver and Case Reports

Background

Nerve transection with nerve reconstruction is part of the treatment algorithm for patients with refractory pain after greater occipital nerve (GON) and lesser occipital nerve (LON) decompression or during primary decompression when severe nerve injury or neuroma formation is present. Importantly, the residual nerve stump is often best addressed via contemporary nerve reconstruction techniques to avoid recurrent pain. As a primary aim of this study, nerve capping is explored as a potential viable alternative that can be utilized in certain headache cases to mitigate pain.

Methods

The technical feasibility of nerve capping after GON/LON transection was evaluated in cadaver dissections and intraoperatively. Patient-reported outcomes in the 3- to 4-month period were compiled from clinic visits. At 1-year follow-up, subjective outcomes and Migraine Headache Index scores were tabulated.

Results

Two patients underwent nerve capping as a treatment for headaches refractory to medical therapy and surgical decompressions with significant improvement to total resolution of pain without postoperative complications. These improvements on pain frequency, intensity, and duration remained stable at a 1-year time point (Migraine Headache Index score reductions of -180 to -205).

Conclusions

Surgeons should be equipped to address the proximal nerve stump to prevent neuroma and neuropathic pain recurrence. Next to known contemporary nerve reconstruction techniques such as targeted muscle reinnervation/regenerative peripheral nerve interface and relocation nerve grafting, nerve capping is another viable method for surgeons to address the proximal nerve stump in settings of GON and LON pain. This option exhibits short operative time, requires only limited dissection, and yields significant clinical improvement in pain symptoms.

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.

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.

A new insight on peripheral nerve repair: the technique of internal nerve splinting

OBJECTIVE

Neuropathic pain produced by symptomatic neuromas is an important problem after peripheral nerve injury (PNI). End-to-end anastomosis of the nerve stump for PNI is well established but cannot efficiently prevent neuroma-in-continuity formation.

METHODS

Sciatic nerve injury was used in the experimental model. Seventy-two rats were randomly divided into four groups: rats with nerve anastomosis sites supported with silicone tubes represented the internal nerve splinting (INS) group (n = 18); rats with end-to-end nerve anastomosis represented control group 1 (CON1) (n = 18); rats with INS and the nerve anastomosis site represented control group 2 (CON2) (n = 18); and rats that underwent the same surgical procedures for skin and muscle operations but without sciatic nerve injury represented the normal group (n = 18).

RESULTS

Gross evaluations of the nerve anastomosis sites, gastrocnemius muscle atrophy, axonal regeneration and remyelination, neuropathic pain, and scar hyperplasia of the neuromas were performed, as well as motor function evaluations. Axonal regeneration, remyelination, and gastrocnemius muscle atrophy were similar between the INS group and CON1 (p > 0.05). However, neuropathic pain and scar hyperplasia-as evaluated according to the expression of anti-sigma-1 receptor antibody and anti-α-smooth muscle actin, respectively-and the weight ratios of the neuromas were reduced in the INS group compared with those of CON1 and CON2 (p < 0.05).

CONCLUSIONS

Application of INS in nerve repair effectively prevented traumatic neuroma-in-continuity formation and inhibited neuropathic pain without influencing nerve regeneration in rats.

Factors Related to Neuropathic Pain following Lower Extremity Amputation

BACKGROUND

Lower extremity amputations are common, and postoperative neuropathic pain (phantom limb pain or symptomatic neuroma) is frequently reported. The use of active treatment of the nerve end has been shown to reduce pain but requires additional resources and should therefore be performed primarily in high-risk patients. The aim of this study was to identify the factors associated with the development of neuropathic pain following above-the-knee amputation, knee disarticulation, or below-the-knee amputation.

METHODS

Retrospectively, 1565 patients with an average follow-up of 4.3 years who underwent a primary above-the-knee amputation, knee disarticulation, or below-the-knee amputation were identified. Amputation levels for above-the-knee amputations and knee disarticulations were combined as proximal amputation level, with below-the-knee amputations being performed in 61 percent of patients. The primary outcome was neuropathic pain (i.e., phantom limb pain or symptomatic neuroma) based on medical chart review. Multivariable logistic regression was performed to identify independent factors associated with neuropathic pain.

RESULTS

Postoperative neuropathic pain was present in 584 patients (37 percent), with phantom limb pain occurring in 34 percent of patients and symptomatic neuromas occurring in 3.8 percent of patients. Proximal amputation level, normal creatinine levels, and a history of psychiatric disease were associated with neuropathic pain. Diabetes, hypothyroidism, and older age were associated with lower odds of developing neuropathic pain.

CONCLUSIONS

Neuropathic pain following lower extremity amputation is common. Factors influencing nerve regeneration, either increasing (proximal amputations and younger age) or decreasing (diabetes, hypothyroidism, and chronic kidney disease) it, play a role in the development of postamputation neuropathic pain.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, III.

Sensory nerve regeneration and reinnervation in muscle following peripheral nerve injury

Sensory afferent fibers are an important component of motor nerves and compose the majority of axons in many nerves traditionally thought of as "pure" motor nerves. These sensory afferent fibers innervate special sensory end organs in muscle, including muscle spindles that respond to changes in muscle length and Golgi tendons that detect muscle tension. Both play a major role in proprioception, sensorimotor extremity control feedback, and force regulation. After peripheral nerve injury, there is histological and electrophysiological evidence that sensory afferents can reinnervate muscle, including muscle that was not the nerve's original target. Reinnervation can occur after different nerve injury and muscle models, including muscle graft, crush, and transection injuries, and occurs in a nonspecific manner, allowing for cross-innervation to occur. Evidence of cross-innervation includes the following: muscle spindle and Golgi tendon afferent-receptor mismatch, vagal sensory fiber reinnervation of muscle, and cutaneous afferent reinnervation of muscle spindle or Golgi tendons. There are several notable clinical applications of sensory reinnervation and cross-reinnervation of muscle, including restoration of optimal motor control after peripheral nerve repair, flap sensation, sensory protection of denervated muscle, neuroma treatment and prevention, and facilitation of prosthetic sensorimotor control. This review focuses on sensory nerve regeneration and reinnervation in muscle, and the clinical applications of this phenomena. Understanding the physiology and limitations of sensory nerve regeneration and reinnervation in muscle may ultimately facilitate improvement of its clinical applications.

Surgical Approaches for Prevention of Neuroma at Time of Peripheral Nerve Injury

Painful neuroma is a frequent sequela of peripheral nerve injury which can result in pain and decreased quality of life for the patient, often necessitating surgical intervention. End neuromas are benign neural tumors that commonly form after nerve transection, when axons from the proximal nerve stump regenerate in a disorganized manner in an attempt to recreate nerve continuity. Inflammation and collagen remodeling leads to a bulbous end neuroma which can become symptomatic and result in decreased quality of life. This review covers surgical prophylaxis of end neuroma formation at time of injury, rather than treatment of existing neuroma and prevention of recurrence. The current accepted methods to prevent end neuroma formation at time of injury include different mechanisms to inhibit the regenerative response or provide a conduit for organized regrowth, with mixed results. Approaches include proximal nerve stump capping, nerve implantation into bone, muscle and vein, various pharmacologic methods to inhibit axonal growth, and mechanisms to guide axonal growth after injury. This article reviews historical treatments that aimed to prevent end neuroma formation as well as current and experimental treatments, and seeks to provide a concise, comprehensive resource for current and future therapies aimed at preventing neuroma formation.

Variation on a technique for the intra-muscular insertion of nerve endings to minimise neuropathic and residual pain in lower limb amputees: a retrospective cohort study

INTRODUCTION

A major cause of morbidity in lower limb amputees is phantom limb pain (PLP) and residual limb pain (RLP). This study aimed to determine whether a variation of the surgical technique of inserting nerve endings into adjacent muscle bellies at the time of lower limb amputation can decrease the incidence and severity of PLP and RLP.

METHODS

Data were retrospectively collected from January 2015 to January 2021, including eight patients that underwent nerve insertion (NI) and 36 that received standard treatment. Primary outcomes included the 11-point Numerical Rating Scale (NRS) for pain severity, and Patient-Reported Outcomes Measurement Information System (PROMIS) pain intensity, behaviour, and interference. Secondary outcome included Neuro-QoL Lower Extremity Function assessing mobility. Cumulative scores were transformed to standardised t scores.

RESULTS

Across all primary and secondary outcomes, NI patients had lower PLP and RLP. Mean 'worst pain' score was 3.5 out of 10 for PLP in the NI cohort, compared to 4.89 in the control cohort (p = 0.298), and 2.6 out of 10 for RLP in the NI cohort, compared to 4.44 in the control cohort (p = 0.035). Mean 'best pain' and 'current pain' scores were also superior in the NI cohort for PLP (p = 0.003, p = 0.022), and RLP (p = 0.018, p = 0.134). Mean PROMIS t scores were lower for the NI cohort for RLP (40.1 vs 49.4 for pain intensity; p = 0.014, 44.4 vs 48.2 for pain interference; p = 0.085, 42.5 vs 49.9 for pain behaviour; p = 0.025). Mean PROMIS t scores were also lower for the NI cohort for PLP (42.5 vs 52.7 for pain intensity; p = 0.018); 45.0 vs 51.5 for pain interference; p = 0.015, 46.3 vs 51.1 for pain behaviour; p = 0.569). Mean Neuro-QoL t score was lower in NI cohort (45.4 vs 41.9; p = 0.03).

CONCLUSION

Surgical insertion of nerve endings into adjacent muscle bellies during lower limb amputation is a simple yet effective way of minimising PLP and RLP, improving patients' subsequent quality of life. Additional comparisons with targeted muscle reinnervation should be performed to determine the optimal treatment option.

Five-year outcome in chronic regional pain syndrome patient with below knee amputation, implanting nerves into muscle: A case report

Persistent, disabling lower extremity pain, outside the distribution of a single nerve, is termed chronic regional pain syndrome (CRPS), but, in reality, this chronic pain is often due to multiple peripheral nerve injuries. It is the purpose of this report to describe the first application of the "traditional," nerve implantation into muscle, usually used in the treatment of a painful neuroma, as a pre-emptive surgical technique in doing a below knee amputation (BKA). In 2011, a 51-year-old woman developed severe, disabling CRPS, after a series of operations to treat an enchondroma of the left fifth metatarsal. When appropriate peripheral nerve surgeries failed to relieve distal pain, a BKA was elected. The approach to the BKA included implantation of each transected peripheral nerve directly into an adjacent muscle. At 5.0 years after the patient's BKA, the woman reported full use of this extremity, using the prosthesis, and was free of phantom limb and residual limb pain. This anecdotal experience gives insight that long-term relief of lower extremity CRPS can be achieved by a traditional BKA utilizing the approach of implanting each transected nerve into an adjacent muscle.

Revision of Carpal Tunnel Surgery

Carpal tunnel release is one of the most commonly performed upper extremity procedures. The majority of patients experience significant improvement or resolution of their symptoms. However, a small but important subset of patients will experience the failure of their initial surgery. These patients can be grouped into persistent, recurrent, and new symptom categories. The approach to these patients starts with a thorough clinical examination and is supplemented with electrodiagnostic studies. The step-wise surgical management of revision carpal tunnel surgery consists of the proximal exploration of the median nerve, Guyon’s release with neurolysis, the rerelease of the transverse retinaculum, evaluation of the nerve injury, treatment of secondary sites of compression, and potential ancillary procedures. The approach and management of failed carpal tunnel release are reviewed in this article.

Approach to Diagnosis and Treatment of Dorsoradial Hand and Forearm Pain

Dorsoradial forearm and hand pain was historically considered difficult to treat surgically due to a particular susceptibility of the radial sensory nerve (RSN) to injury and/or compression. A nerve block, if it were done at all, was directed at the region of the anatomic snuff box to block the RSN in an effort to provide diagnostic information as to the pain etiology. Even for patients with pain relief following a diagnostic block, resecting the RSN often proved unsuccessful in fully relieving pain. The solution to successful treatment of this refractory pain problem was the realization that the RSN is not the sole source of sensory innervation to the dorsoradial wrist. In fact, in 75% of people the lateral antebrachial cutaneous nerve (LABCN) dermatome overlaps the RSN with other nerves, such as the dorsal ulnar cutaneous nerve and even the posterior antebrachial cutaneous nerves, occasionally providing sensory innervation to the same area. With this more refined understanding of the cutaneous neuroanatomy of the wrist, the diagnostic nerve block algorithm was expanded to include selective blockage of more than just the RSN. In contemporary practice, identification of the exact nerves responsible for pain signal generation informs surgical decision-making for palliative neurolysis or neurectomy. This approach offers a systematic and repeatable method to inform the diagnosis and treatment of dorsoradial forearm and wrist pain.

Dermatosensory Peripheral Nerve Interfaces: Prevention of Pain Recurrence Following Sensory Neurectomy

Chronic pain is a significant health care problem. Many patients' pain can be linked to a neuropathic origin, diagnosed with a thorough history and physical examination, and confirmed with a diagnostic nerve block. There are new procedures designed to address neuropathic pain from symptomatic neuromas by providing physiologic targets for regenerating axons following neurectomy. Dermal wrapping of the end of a sensory nerve following transection, a technique called dermatosensory peripheral nerve interface, may provide an optimal environment to prevent neuroma pain and reduce chronic neuropathic pain.

Traditional Neuroma Management

With the development of newer techniques for symptomatic neuroma treatment, such as regenerative peripheral nerve interface and targeted muscle reinnervation, transposition and coverage techniques often have been referred to as "passive techniques." In spite of its negative connotation, these passive techniques yield positive results in a majority of patients treated. The experienced surgeon has more options than ever before in the prevention and management of problematic neuromas. Critical appraisal of the current literature reveals no single, optimal standard of care. Instead, surgeons have a plethora of useful techniques that can be implemented on a case-by-case basis to optimize outcomes.

Dorsal Coaptation for the Treatment of Digital Neuroma

PURPOSE

The formation of a symptomatic neuroma after digital tip amputation presents a vexing problem. There is currently no procedure that completely and consistently prevents hypersensitive neuroma formation. This report presents the results of a technique designed to limit axon regeneration and mechanical irritation by neuroma excision, dorsal transposition, and coaptation with the corresponding digital nerve.

METHODS

A retrospective chart review was conducted to assess the effectiveness of neuroma excision with dorsal transposition and epineurial coaptation for postamputation symptomatic digital neuromas. Neuromas were excised using a midlateral fish-mouth incision. Digital nerves were mobilized to the dorsum of the digital tip and coapted using 9-0 nylon epineurial suture. The procedure was modified to salvage viable fingernails or to avoid excessive tension. Mass et al's criteria system was used to evaluate effectiveness.

RESULTS

Twenty-four patients with painful neuromas of the radial and ulnar digital nerves after traumatic amputation were included. Thirty-two digits underwent dorsal coaptation. This procedure was associated with a result considered good or excellent in 28 of 32 digits. Twenty-seven of 32 digits registered no pain or stump anesthesia after dorsal coaptation. Twenty-five of 32 digits demonstrated no interference with activities of daily living. Twenty-one of 24 patients returned to work.

CONCLUSIONS

Neuroma excision with dorsal transposition and epineurial coaptation is an effective treatment for postamputation symptomatic digital neuroma.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Reset Neurectomy for Cutaneous Nerve Injuries

Diffuse cutaneous nerve injuries, often caused by a crush mechanism, are challenging for the nerve surgeon. Discrete nerve transections and focal neuromas are easier to identify and have a more distinct treatment algorithm. Following crush injury to a noncritical sensory nerve, a successful local anesthetic block proximal to the injury may help determine the possibility of surgical intervention. In these cases, we describe a technique of “reset neurectomy” whereby a neurectomy is performed proximal to the zone of injury, and immediate repair or reconstruction (with or without a nerve graft) is performed. This technique may be useful in cases of diffuse, nontransection nerve injuries in which neuropathic pain is the primary symptom.

Treatment of Neuroma of the Dorsal Branch of the Ulnar Nerve With Transfer to the Distal Anterior Interosseous Nerve

Painful neuromas of the dorsal branch of the ulnar nerve may be difficult to treat. Proximal transposition is the standard treatment, but pain may recur. Sensory-to-motor nerve transfer as an evolution of targeted muscle reinnervation is a recently described technique to reduce neuroma formation in the treatment of painful neuromas. This report describes sensory-to-motor transfer of the dorsal branch of the ulnar nerve to the distal anterior interosseous nerve to treat a painful neuroma.

Risk Factors for Neuropathic Pain Following Major Upper Extremity Amputation

BACKGROUND

 Active treatment (targeted muscle reinnervation [TMR] or regenerative peripheral nerve interfaces [RPNIs]) of the amputated nerve ends has gained momentum to mitigate neuropathic pain following amputation. Therefore, the aim of this study is to determine the predictors for the development of neuropathic pain after major upper extremity amputation.

METHODS

 Retrospectively, 142 adult patients who underwent 148 amputations of the upper extremity between 2000 and 2019 were identified through medical chart review. All upper extremity amputations proximal to the metacarpophalangeal joints were included. Patients with a follow-up of less than 6 months and those who underwent TMR or RPNI at the time of amputation were excluded. Neuropathic pain was defined as phantom limb pain or a symptomatic neuroma reported in the medical charts at 6 months postoperatively. Most common indications for amputation were oncology (n = 53, 37%) and trauma (n = 45, 32%), with transhumeral amputations (n = 44, 30%) and shoulder amputations (n = 37, 25%) being the most prevalent.

RESULTS

 Neuropathic pain occurred in 42% of patients, of which 48 (32%) had phantom limb pain, 8 (5.4%) had a symptomatic neuroma, and 6 (4.1%) had a combination of both. In multivariable analysis, traumatic amputations (odds ratio [OR]: 4.1, p = 0.015), transhumeral amputations (OR: 3.9, p = 0.024), and forequarter amputations (OR: 8.4, p = 0.003) were independently associated with the development of neuropathic pain.

CONCLUSION

 In patients with an upper extremity amputation proximal to the elbow or for trauma, there is an increased risk of developing neuropathic pain. In these patients, primary TMR/RPNI should be considered and this warrants a multidisciplinary approach involving general trauma surgeons, orthopaedic surgeons, plastic surgeons, and vascular surgeons.

Targeted muscle reinnervation for the management of pain in the setting of major limb amputation

The life altering nature of major limb amputations may be further complicated by neuroma formation in up to 60% of the estimated 2 million major limb amputees in the United States. This can be a source of pain and functional limitation of the residual limb. Pain associated with neuromas may limit prosthetic limb use, require reoperation, lead to opioid dependence, and dramatically reduce quality of life. A number of management options have been described including excision alone, excision with repair, excision with transposition, and targeted muscle reinnervation. Targeted muscle reinnervation has been shown to reduce phantom limb and neuroma pain for patients with upper and lower extremity amputations. It may be performed at the time of initial amputation to prevent pain development or secondarily for the treatment of established pain. Encouraging outcomes have been reported, and targeted muscle reinnervation is emerging as a leading surgical technique for pain prevention in patients undergoing major limb amputations and pain management in patients with pre-existing amputations.

Patient-Reported Outcomes following Surgical Treatment of Symptomatic Digital Neuromas

BACKGROUND

Many surgical techniques are used to treat symptomatic neuroma, but options are limited for digital neuromas because of a paucity of soft-tissue coverage and/or the absence of the terminal nerve end. The authors assessed factors that influence patient-reported outcomes after surgery for symptomatic digital neuroma.

METHODS

The authors retrospectively identified 29 patients with 33 symptomatic digital neuromas that were treated surgically. Patients completed the Patient-Reported Outcomes Measurement Information System (PROMIS) Upper Extremity and Pain Interference scales, a numeric rating scale for pain, and the PROMIS Depression scale at a median follow-up of 7.6 years postoperatively (range, 3.2 to 16.8 years). Surgical treatment for neuroma included excision with nerve repair/reconstruction (n =13; 39 percent), neuroma excision alone (n =10; 30 percent), and excision and implantation (n =10; 30 percent). Multivariable linear regression was performed to identify the factors that independently influenced patient-reported outcomes.

RESULTS

The mean postoperative PROMIS Upper Extremity score was 45.2 ± 11.2, the mean Pain Interference score was 54.3 ± 10.7, and the mean numeric rating scale pain score was 3 (interquartile range, 1 to 5). Compared with other treatment techniques, neuroma excision with nerve repair/reconstruction was associated with lower numeric rating scale pain scores; lower Pain Interference scores, corresponding to less daily impact of pain; and higher Upper Extremity scores, reflecting better upper extremity function. Older age and higher Depression scores were associated with lower Upper Extremity scores and higher Pain Interference scores. Smoking was associated with higher Pain Interference and numeric rating scale pain scores.

CONCLUSIONS

Neuroma excision followed by nerve repair/reconstruction resulted in better outcomes compared with neuroma excision alone with or without implantation. Patient age and psychosocial factors influenced patient-reported outcomes.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, III.

Covering the proximal nerve stump with chondroitin sulfate proteoglycans prevents traumatic painful neuroma formation by blocking axon regeneration after neurotomy in Sprague Dawley rats

OBJECTIVE

Neuropathic pain caused by traumatic neuromas is an extremely intractable clinical problem. Disorderly scar tissue accumulation and irregular and immature axon regeneration around the injury site mainly contribute to traumatic painful neuroma formation. Therefore, successfully preventing traumatic painful neuroma formation requires the effective inhibition of irregular axon regeneration and disorderly accumulation of scar tissue. Considering that chondroitin sulfate proteoglycans (CSPGs) can act on the growth cone and effectively inhibit axon regeneration, the authors designed and manufactured a CSPG-gelatin blocker to regulate the CSPGs' spatial distribution artificially and applied it in a rat model after sciatic nerve neurectomy to evaluate its effects in preventing traumatic painful neuroma formation.

METHODS

Sixty female Sprague Dawley rats were randomly divided into three groups (positive group: no covering; blank group: covering with gelatin blocker; and CSPG group: covering with the CSPG-gelatin blocker). Pain-related factors were evaluated 2 and 8 weeks postoperatively (n = 30). Neuroma growth, autotomy behavior, and histological features of the neuromas were assessed 8 weeks postoperatively (n = 30).

RESULTS

Eight weeks postoperatively, typical bulb-shaped neuromas did not form in the CSPG group, and autotomy behavior was obviously better in the CSPG group (p < 0.01) than in the other two groups. Also, in the CSPG group the regenerated axons showed a lower density and more regular and improved myelination (p < 0.01). Additionally, the distribution and density of collagenous fibers and the expression of α-smooth muscle actin were significantly lower in the CSPG group than in the positive group (p < 0.01). Regarding pain-related factors, c-fos, substance P, interleukin (IL)-17, and IL-1β levels were significantly lower in the CSPG group than those in the positive and blank groups 2 weeks postoperatively (p < 0.05), while substance P and IL-17 remained lower in the CSPG group 8 weeks postoperatively (p < 0.05).

CONCLUSIONS

The authors found that CSPGs loaded in a gelatin blocker can prevent traumatic neuroma formation and effectively relieve pain symptoms after sciatic nerve neurotomy by blocking irregular axon regeneration and disorderly collagenous fiber accumulation in the proximal nerve stump. These results indicate that covering the proximal nerve stump with CSPGs may be a new and promising strategy to prevent traumatic painful neuroma formation in the clinical setting.

Neuroma

Neuroma formation occurs because of some degree of nerve injury followed by improper intrinsic nerve repair. The cause of neuroma pain is incompletely understood, but appears to be multifactorial in nature, including local and system changes. A comprehensive understanding of nerve anatomy, injury, and repair techniques should be used when dealing with neuroma formation and its physical manifestations. Diagnosis of neuroma is clinically characterized by pain associated with scar, altered sensation within the given nerve distribution, and a Tinel sign. The pathophysiology of neuroma formation is reviewed.

A Retrospective Case Series Reporting the Outcomes of Avance Nerve Allografts in the Treatment of Peripheral Nerve Injuries

BACKGROUND

Acellular nerve allografts are a viable treatment modality for bridging nerve gaps. Several small studies have demonstrated results equal to those of autologous grafts; however, there is information lacking with regard to outcomes for wider indications. The authors evaluated the outcomes of patients treated with a nerve allograft in a variety of clinical situations.

METHODS

A retrospective chart analysis was completed between April of 2009 and October of 2017. Inclusion criteria were age 18 years or older at the time of surgery and treatment with a nerve allograft. Patients were excluded if they had not been followed up for a minimum of 6 months. The modified Medical Research Council Classification was used to monitor motor and sensory changes in the postoperative period.

RESULTS

Two hundred seven nerve allografts were used in 156 patients; of these, 129 patients with 171 nerve allografts fulfilled the inclusion criteria. Seventy-seven percent of patients achieved a sensory outcome score of S3 or above and 36 percent achieved a motor score of M3 or above. All patients with chronic pain had improvement of their symptoms. Graft length and diameter were negatively correlated with reported outcomes. One patient elected to undergo revision surgery, and the original graft was shown histologically to have extensive central necrosis. Anatomically, allografts used for lower limb reconstruction yielded the poorest results. All chronic patients had a significantly lower postoperative requirement for analgesia, and allografts were effective in not only reducing pain but also restoring a functional level of sensation.

CONCLUSIONS

This study supports the wider application of allografts in managing nerve problems. However, caution must be applied to the use of long grafts with larger diameters.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Coaptation of Cutaneous Nerves for Intractable Stump Pain and Phantom Limb Pain after Upper Limb Amputation

Background

Various surgical treatments have been advocated for stump pain and phantom limb pain after limb amputation but the most effective is unknown. We report a case of intractable stump pain and phantom limb pain of the upper limb, which was successfully treated by end-to-end coaptation of the cutaneous nerves after multimodal treatment failures.

Case description

A 39-year-old man was referred to our department with a history of severe stump neuroma-related pain and phantom limb pain of his right upper limb. He had undergone multiple treatments over 26 years including medication, nerve blocks, and repeated surgeries. None had been successful for relief of pain. The clinical assessment showed a point of marked tenderness around the medial stump of the upper arm. Ultrasound-guided peripheral infiltration of local anaesthetic around the medial stump produced significant relief of his pain. Exploration around the medial limb stump revealed two stump neuromas of the medial cutaneous nerves of the forearm. Both stump neuromas were resected, and their stumps were coapted to each other. After 4 years, he was completely relieved of his pain and without any sensory deficit.

Conclusion

Successful nerve coaptations for painful stump neuromas of the upper limb are reported rarely. This case suggests this method can be helpful. The patient burden was minimal because it involved the resection and coaptation of the two neuromas. This method should be encouraged for cases of intractable stump-related pain in the upper limb.

How to cite this article

Kadota H, Ishida K. Coaptation of Cutaneous Nerves for Intractable Stump Pain and Phantom Limb Pain after Upper Limb Amputation. Strategies Trauma Limb Reconstr 2020;15(1):50-53.

Mechanisms for Reducing Neuropathic Pain

Injury typically results in the development of neuropathic pain, but the pain normally decreases and disappears in paralleled with wound healing. The pain results from cells resident at, and recruited to, the injury site releasing pro-inflammatory cytokines and other mediators leading to the development of pro-inflammatory environment and causing nociceptive neurons to develop chronic ectopic electrical activity, which underlies neuropathic pain. The pain decreases as some of the cells that induce pro-inflammation, changing their phenotype leading to the blocking the release of pro-inflammatory mediators while releasing anti-inflammatory mediators, and blocking nociceptive neuron chronic spontaneous electrical activity. Often, despite apparent wound healing, the neuropathic pain becomes chronic. This raises the question of how chronic pain can be eliminated. While many of the cells and mediators contributing to the development and maintenance of neuropathic pain are known, a better understanding is required of how the injury site environment can be controlled to permanently eliminate the pro-inflammatory environment and silence the chronically electrically active nociceptive neurons. This paper examines how methods that can promote the transition of the pro-inflammatory injury site to an anti-inflammatory state, by changing the composition of local cell types, modifying the activity of pro- and anti-inflammatory receptors, inducing the release of anti-inflammatory mediators, and silencing the chronically electrically active nociceptive neurons. It also examines the hypothesis that factors released from platelet-rich plasma applied to chronic pain sites can permanently eliminate chronic inflammation and its associated chronic pain.

Novel experimental surgical strategy to prevent traumatic neuroma formation by combining a 3D-printed Y-tube with an autograft

OBJECTIVE Traumatic neuromas may develop after nerve injury at the proximal nerve stump, which can lead to neuropathic pain. These neuromas are often resistant to therapy, and excision of the neuroma frequently leads to recurrence. In this study, the authors present a novel surgical strategy to prevent neuroma formation based on the principle of centro-central anastomosis (CCA), but rather than directly connecting the nerve ends to an autograft, they created a loop using a 3D-printed polyethylene Y-shaped conduit with an autograft in the distal outlets. METHODS The 3D-printed Y-tube with autograft was investigated in a model of rat sciatic nerve transection in which the Y-tube was placed on the proximal sciatic nerve stump and a peroneal graft was placed between the distal outlets of the Y-tube to form a closed loop. This model was compared with a CCA model, in which a loop was created between the proximal tibial and peroneal nerves with a peroneal autograft. Additional control groups consisted of the closed Y-tube and the extended-arm Y-tube. Results were analyzed at 12 weeks of survival using nerve morphometry for the occurrence of neuroma formation and axonal regeneration in plastic semi-thin sections. RESULTS Among the different surgical groups, the Y-tube with interposed autograft was the only model that did not result in neuroma formation at 12 weeks of survival. In addition, a 13% reduction in the number of myelinated axons regenerating through the interposed autograft was observed in the Y-tube with autograft model. In the CCA model, the authors also observed a decrease of 17% in the number of myelinated axons, but neuroma formation was present in this model. The closed Y-tube resulted in minimal nerve regeneration inside the tube together with extensive neuroma formation before the entrance of the tube. The extended-arm Y-tube model clearly showed that the majority of the regenerating axons merged into the Y-tube arm, which was connected to the autograft, leaving the extended plastic arm almost empty. CONCLUSIONS This pilot study shows that our novel 3D-printed Y-tube model with interposed autograft prevents neuroma formation, making this a promising surgical tool for the management of traumatic neuromas.

Surgical Management of Neuromas of the Hand and Wrist

Neuromas of the hand and wrist are common causes of peripheral nerve pain. Neuromas are formed after the nerve sustains an injury, and they can be debilitating and painful. The diagnosis is made by a thorough history and physical examination. The treatment options are quite varied, but conservative measures tailored to the patient should be initiated first. No surgical treatment has been proven superior to others or to nonsurgical treatment.

Etiology and Treatment Outcomes for Sural Neuroma

BACKGROUND

Neuroma results from disorganized regeneration following nerve injury and may be symptomatic. The aim of this study was to investigate the causes, treatment, and outcomes of operatively treated sural neuromas, and to describe the factors associated with persistent or unchanged postoperative pain symptoms.

METHODS

Consecutive patients with surgically treated sural neuromas in a 14-year period were identified using Current Procedural Terminology (CPT) codes ( n = 49), followed by a chart review to collect patient and treatment characteristics. Postoperative pain symptoms were categorized as complete resolution of pain, improvement of pain, no change in pain, or worse pain. The median patient age was 46.5 years (interquartile range [IQR], 39.1-51.3), and median follow-up was 4.0 years (IQR, 1.9-9.2).

RESULTS

Ninety percent of symptomatic sural neuromas developed as a result of previous lower extremity surgery. Initial surgery of sural neuroma led to improvement in pain in 63% of patients, and an additional 8.2% of the patients had improvement after secondary neuroma surgery. Pain relief after diagnostic injection showed a trend toward an association with postoperative pain improvement. Neuroma excision and implantation in muscle was the most common surgical technique used (67%). Four of the 7 patients that underwent a second neuroma operation reported symptom improvement.

CONCLUSION

Sural neuromas may arise from prior surgery or trauma to the lower extremity. Surgical intervention resulted in either improvement or complete resolution of pain symptoms in 71% of patients, although occasionally more than one procedure was required to obtain symptomatic relief. Preoperative anesthetic injection may help identify patients that benefit from neuroma surgery. Level of Evidence: Level IV, retrospective case series.

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

A consensus on the optimal treatment of painful neuromas does not exist. Our objective was to identify available data and to examine the role of surgical technique on outcomes following surgical management of painful neuromas. In accordance with the PRISMA guidelines, we performed a comprehensive literature search to identify studies measuring the efficacy of the surgical treatment of painful neuromas in the extremities (excluding Morton's neuroma and compression neuropathies). Surgical treatments were categorized as excision-only, excision and transposition, excision and cap, excision and repair, or neurolysis and coverage. Data on the proportion of patients with a meaningful reduction in pain were pooled and a random-effects meta-analysis was performed. The effects of confounding, study quality, and publication bias were examined with stratified, meta-regression, and bias analysis. Fifty-four articles met the inclusion criteria, many with multiple treatment groups. Outcomes reporting varied significantly and few studies controlled for confounding. Overall, surgical treatment of neuroma pain was effective in 77% of patients [95% confidence interval: 73-81]. No significant differences were seen between surgical techniques. Among studies with a mean pain duration greater than 24 months, or median number of operations greater than 2 prior to definitive neuroma pain surgery, excision and transposition or neurolysis and coverage were significantly more likely than other operative techniques to result in a meaningful reduction in pain (P < 0.05). Standardization in the reporting of surgical techniques, outcomes, and confounding factors is needed in future studies to enable providers to make comparisons across disparate techniques in the surgical treatment of neuroma pain.

Selective motor fascicle transfer and neural-machine interface: case report

An amputated nerve transferred to a nearby muscle produces a transcutaneously detectable electromyographic signal corresponding to the transferred nerve; this technique is known as targeted muscle reinnervation (TMR). There are 2 issues to overcome to improve this technique: the caliber and the selectivity of the transferred nerve. It is optimal to select and transfer each motor fascicle to achieve highly developed myoelectric arms with multiple degrees-of-freedom motion. The authors report on a case in which they first identified the remnant stumps of the amputated median and radial nerves and then identified the sensory fascicles using somatosensory evoked potentials. Each median nerve fascicle was transferred to the long head branch of the biceps or the brachialis branch, while the short head branch of the biceps was retained for elbow flexion. Each radial nerve fascicle was transferred to the medial or lateral head branch of the triceps, while the long head branch of the triceps was retained for elbow extension. Electrophysiological and functional tests were conducted in the reinnervated muscles. Functional and electrophysiological improvement was noted, with marked improvement in the identification rate for each digit, forearm, and elbow motion after the selective nerve transfers. The authors note that more selective nerve transfers may be required for the development of prostheses with multiple degrees of freedom.

Nerve capping with a nerve conduit for the treatment of painful neuroma in the rat sciatic nerve

OBJECTIVE

Treatment of painful neuroma remains difficult, despite the availability of numerous surgical procedures. Recently, nerve capping treatment for painful neuroma using artificial nerve conduits has been introduced in clinical and basic research. However, the appropriate length of the nerve conduit and the pain relief mechanism have not been determined. In this study the authors aimed to investigate nerve capping treatment with a bioabsorbable nerve conduit using the rat sciatic nerve amputation model. Using histological analysis, the authors focused on the nerve conduit length and pain relief mechanism.

METHODS

Sixteen Sprague Dawley rats were evaluated for neuropathic pain using an autotomy (self-amputation) score and gross and histological changes of the nerve stump 2, 4, 8, and 12 weeks after sciatic nerve neurectomy without capping. Forty-five rats were divided into 3 experimental groups, no capping (control; n = 15), capping with a 3-mm nerve conduit (n = 15), and capping with a 6-mm nerve conduit (n = 15). All rats were evaluated using an autotomy score and nerve stump histology 12 weeks after neurectomy. The nerve conduit was approximately 0.5 mm larger than the 1.5-mm diameter of the rat sciatic nerves to prevent nerve constriction.

RESULTS

The autotomy scores gradually exacerbated with time. Without capping, a typical bulbous neuroma was formed due to random axonal regeneration 2 weeks after neurectomy. Subsequently, the adhesion surrounding the neuroma expanded over time for 12 weeks, and at the 12-week time point, the highest average autotomy scores were observed in the no-capping (control) group, followed by the 3- and the 6-mm nerve conduit groups. Histologically, the distal axonal fibers became thinner and terminated within the 6-mm nerve conduit, whereas they were elongated and protruded across the 3-mm nerve conduit. Minimal perineural scar formation was present around the terminated axonal fibers in the 6-mm nerve conduit group. Expressions of anti-α smooth muscle actin and anti-sigma-1 receptor antibodies in the nerve stump significantly decreased in the 6-mm nerve conduit group.

CONCLUSIONS

In the rat sciatic nerve amputation model, nerve capping treatment with a bioabsorbable nerve conduit provided relief from neuroma-induced neuropathic pain and prevented perineural scar formation and neuroinflammation around the nerve stump. The appropriate nerve conduit length was determined to be more than 4 times the diameter of the original nerve.

Treatment of a patient suffering from posttraumatic painful neuromas formed at the bilateral digital nerves of the left middle finger using two neurovascular island flaps

Hand surgeons often encounter painful posttraumatic neuromas in daily practice and the treatment of these neuromas is still challenging for them, because of the tendency of recurrence.^1,2 The patient injured his left middle finger and was treated by amputation in a previous hospital. After this operation, the patient started to feel pain at the fingertip and complained of severe electric radiating pain when the radial and ulnar ends of the finger were touched. We treated painful neuromas formed on both palmar digital nerve stumps using a reverse pedicle island flap containing subcutaneous nerves, which were connected to the nerve stumps after removal of the neuromas of the finger. This maneuver relieved the finger pain completely. Removal of finger digital nerve neuromas, connecting the nerve stumps to the subcutaneous nerves included in a skin island flap and, covering the neurorrhaphy sites with the flap may have reduced the chance of the recurrence of neuromas and resulted in restoration of considerable function of the hand.

A review of main anatomical and sonographic features of subcutaneous nerve injuries related to orthopedic surgery

Lesion to subcutaneous nerves is a well-known risk of orthopedic surgery and a significant cause of postoperative pain and dissatisfaction in patients. High-resolution ultrasound can be used to visualize the vast majority of small subcutaneous nerves of the upper and lower limbs. Ultrasound detects nerve abnormalities such as focal hypoechoic thickening, stump neuroma, and scar encasement, and provides information not only about the peripheral nerve itself but also about its relationship to adjacent anatomical structures. The purpose of this review is to provide an overview of the anatomy of the main subcutaneous nerves damaged during orthopedic surgery, recall at-risk procedures, and offer useful anatomic landmarks to help the sonographer identify and follow the nerves when an iatrogenic lesion is suspected.

Tratamiento quirúrgico de los síndromes dolorosos regionales complejos tipo II y utilidad de la monitorización neurofisiológica intraoperatoria

El propósito de esta revisión era presentar las bases bilógicas y fisiopatológicas de la formación de neuromas como causa de los síndromes dolorosos regional (SDRC) tipo II y el uso de la monitorización neurofisiológica intraoperatoria en el tratamiento de los SDRC tipo II secundarios a neuromas en continuidad y en nervios adheridos en cicatrices tras cirugías previas.

Influence of Blood Flow on the Neuroma Formation after Transposition of the Nerve Stump into Vein: Experimental and Clinical Study

We study the influence of blood flow on the neuroma formation after transposition of the nerve stump into a vein. A total of 30 rats were divided into two groups. In group (I), a 10-mm segment of the femoral vein was excluded from the blood stream. A venotomy was performed in the middle of this segment. The proximal nerve stump of femoral nerve was transposed into the lumen of the femoral vein via a venotomy and held with an epineural suture through the venous wall. In group (II), the same technique was used as in group (I) but without exclusion of the vein segment from blood flow. The control side of the femoral nerve was transected and then was left in place. All animals were sacrificed after 28 weeks. Histopathological evaluation was performed postoperatively; serial transverse sections were made to find the largest diameter of the neuroma. Selected specimens were processed for electron microscopy examination. The following parameters were assessed in both the groups: cross-sectional area of neuromas; myelinated axons; and neural tissue to connective tissue ratio. In group (I), the proximal end of the tibial nerve formed a nonclassic neuroma. In group (II), the proximal end of the tibial nerve formed a nonclassic neuroma smaller in diameter than group (I). The proximal end of the femoral nerve of the control sides in both groups formed a classic neuroma larger in diameter than the experimental sides in both the groups. A Kruskal-Wallis H test showed that there was a statistically significant difference in myelinated axons between the different groups, X² (3) = 36.19, p < 0.001. The average neural tissue to connective tissue ratio in the control group (I) ranged from 39.2 to 85.8%, but on the experimental side, it was more or less equalized. The average of a neural tissue to connective tissue ratio of the group (II) ranged from 59.1 to 63.9% in the treatment sides as compared to 28.6 to 82.4% in the control sides. The clinical experience utilizing the same technique in the treatment of 10 patients of painful neuromas of the superficial radial nerve and digital nerves were presented with encouraging results. The blood flow has a considerable effect on neuroma formation. We recommend a further study to know the fine details about the exact role of blood as the bloodstream may carry away neurotrophic factors that may also be released by the nerve stump itself.

Treatment of Foot and Ankle Neuroma Pain With Processed Nerve Allografts

BACKGROUND

Localized nerve pain in the foot and ankle can be a chronic source of disability after trauma and has been identified as the most common complication following operative interventions in the foot and ankle. The superficial location of the injured nerves and lack of suitable tissue for nerve implantation make this pain refractory to conventional methods of neuroma management. We describe a novel strategy for management using processed nerve allografts to bridge nerve gaps created by resection of both end neuromas and neuromas-in-continuity.

METHODS

A retrospective review of a prospectively maintained database was performed of all patients who received a processed nerve allograft for treatment of painful neuromas in the foot and ankle between May 2010 and June 2015. Patient demographic and operative information was obtained, as well as preoperative and postoperative pain assessments using a conventional ordinal scale and PROMIS (Patient Reported Outcomes Measurement Information System) Pain Behavior and Pain Interference assessments. Twenty-two patients were identified, with postoperative pain assessments occurring at a mean of 15.5 months after surgery.

RESULTS

Neuromas of the sural and superficial peroneal nerves were the most common diagnoses, with 3-cm nerve allografts being used as the interposition graft in the majority of cases. Eight patients had end neuromas and 18 patients had neuromas in continuity. Analysis of paired data demonstrated a mean ordinal pain score decrease of 2.6, with 24 and 31 percentage-point decreases in PROMIS Pain Behavior and Pain Interference measures, respectively. All changes were significant (P < .002).

CONCLUSION

The painful sequelae of superficial nerve injuries in the foot and ankle was significantly improved with complete excision of the involved nerve segment followed by bridging of the resulting nerve gap with a processed nerve allograft. This approach limits surgery to the site of injury and reconstitutes the peripheral nerve anatomy.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Management of Pain in Complex Nerve Injuries

Traumatic nerve injuries can be devastating and life-changing events, leading to functional morbidity and psychological stress and social constraints. Even in the event of a successful surgical repair with recovered motor function, pain can result in continued disability and poor quality of life. Pain after nerve injury can also prevent recovery and return to preinjury life. It is difficult to predict which patients will develop persistent pain; once incurred, pain can be even challenging to manage. This review seeks to define the types of pain following peripheral nerve injuries, investigate the pathophysiology and causative factors, and evaluate potential treatment options.

Surgical Treatment of Upper Extremity Pain

If the patient with hand pain remains without significant relief and without recovery of function after appropriate pharmaceutical and physical modality treatments, it is appropriate to consider a surgical approach to the pain. Categories of pain amenable to a surgical approach are pain caused by nerve compression, pain caused by a neuroma, and joint pain of neural origin. Compressed nerve should be decompressed and depending on the intraoperative findings a neurolysis also should be performed. Painful neuroma must be resected to stop the pain generator. For a painful joint, the biomechanics of that joint must first be stable before denervation.