Management of neuromas

Surgical Management of Chronic Neuropathic Burn Pain

Burn-related chronic neuropathic pain can contribute to a decreased quality of life. When medical and pharmacologic therapies prove ineffective, patients should undergo evaluation for surgical intervention, consisting of a detailed physical examination and elective diagnostic nerve block, to identify an anatomic cause of pain. Based on symptoms and physical examination findings, particularly Tinel's sign, treatments can vary, including a trial of laser therapies, fat grafting, or nerve surgeries (nerve decompression, neuroma excision, targeted muscle reinnervation, regenerative peripheral nerve interfaces, and vascularized denervated muscle targets). It is essential to counsel patients to establish appropriate expectations prior to treatment with a multidisciplinary team.

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.

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.

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.

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.

Cortical Reorganization after Limb Loss: Bridging the Gap between Basic Science and Clinical Recovery

Despite the increasing incidence and prevalence of amputation across the globe, individuals with acquired limb loss continue to struggle with functional recovery and chronic pain. A more complete understanding of the motor and sensory remodeling of the peripheral and central nervous system that occurs postamputation may help advance clinical interventions to improve the quality of life for individuals with acquired limb loss. The purpose of this article is to first provide background clinical context on individuals with acquired limb loss and then to provide a comprehensive review of the known motor and sensory neural adaptations from both animal models and human clinical trials. Finally, the article bridges the gap between basic science researchers and clinicians that treat individuals with limb loss by explaining how current clinical treatments may restore function and modulate phantom limb pain using the underlying neural adaptations described above. This review should encourage the further development of novel treatments with known neurological targets to improve the recovery of individuals postamputation.Significance Statement In the United States, 1.6 million people live with limb loss; this number is expected to more than double by 2050. Improved surgical procedures enhance recovery, and new prosthetics and neural interfaces can replace missing limbs with those that communicate bidirectionally with the brain. These advances have been fairly successful, but still most patients experience persistent problems like phantom limb pain, and others discontinue prostheses instead of learning to use them daily. These problematic patient outcomes may be due in part to the lack of consensus among basic and clinical researchers regarding the plasticity mechanisms that occur in the brain after amputation injuries. Here we review results from clinical and animal model studies to bridge this clinical-basic science gap.

Micro-nanofiber composite biomimetic conduits promote long-gap peripheral nerve regeneration in canine models

Peripheral nerve injuries may result in severe long-gap interruptions that are challenging to repair. Autografting is the gold standard surgical approach for repairing long-gap nerve injuries but can result in prominent donor-site complications. Instead, imitating the native neural microarchitecture using synthetic conduits is expected to offer an alternative strategy for improving nerve regeneration. Here, we designed nerve conduits composed of high-resolution anisotropic microfiber grid-cordes with randomly organized nanofiber sheaths to interrogate the positive effects of these biomimetic structures on peripheral nerve regeneration. Anisotropic microfiber-grids demonstrated the capacity to directionally guide Schwann cells and neurites. Nanofiber sheaths conveyed adequate elasticity and permeability, whilst exhibiting a barrier function against the infiltration of fibroblasts. We then used the composite nerve conduits bridge 30-mm long sciatic nerve defects in canine models. At 12 months post-implant, the morphometric and histological recovery, gait recovery, electrophysiological function, and degree of muscle atrophy were assessed. The newly regenerated nerve tissue that formed within the composite nerve conduits showed restored neurological functions that were superior compared to sheaths-only scaffolds and Neurolac nerve conduit controls. Our findings demonstrate the feasibility of using synthetic biophysical cues to effectively bridge long-gap peripheral nerve injuries and indicates the promising clinical application prospects of biomimetic composite nerve conduits.

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.

Neuromas cause severe residual problems at long-term despite surgery

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

Sural hypersensitivity after nerve transection depends on anatomical differences in the distal tibial nerve of mice and rats

INTRODUCTION

Various mouse and rat models of neuropathic pain after nerve injury exist. Whilst some models involve a proximal nerve lesion or ligation of the sciatic trifurcation in mice and rats, others consists of a transection or ligation of distal nerves at the tibial bifurcation in mice or rats. The level of nerve cut directly affects the magnitude of hypersensitivity, and anatomical differences between mice and rats might therefore impact the development of hypersensitivity after distal tibial nerve transection as well.

METHODS

The bifurcation of the distal tibial nerve into the medial and lateral plantar nerve (MPN and LPN), and the presence of anatomical differences in sural and tibial nerve distribution between mice and rat was evaluated. Sural mechanical sensitivity after transection of the MPN or whole tibial nerve was assessed using von Frey test until 8 weeks after surgery in 48 rats and 16 mice.

RESULTS

The bifurcation of the tibial nerve into the MPN and LPN is situated proximal to the ankle in both mice and rats. The sural nerve joins the LPN in mice, but not in rats. A proximal communicating branch is present between the LPN and MPN in rats, but not in mice. MPN transection in mice caused hypersensitivity of the hindpaw innervated by the sural nerve, but not in rats. In rats, sural hypersensitivity only developed when both MPN and LPN were cut.

CONCLUSION

Inter-species variation in nerve anatomy should be taken in consideration when performing surgery to induce plantar hypersensitivity in rodents.

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.

Vascularized, Denervated Muscle Targets for Treatment of Symptomatic Neuromas in the Upper Extremity: Description of Operative Technique

Symptomatic neuromas of the upper extremity often cause persistent, debilitating pain that is resistant to medical management. Following upper extremity amputation, painful neuromas may disrupt rehabilitation efforts and pose a barrier to prosthetic use. Several surgical approaches have been attempted to treat neuromas, each of which suffers from limitations. We have developed a novel technique, the vascularized, denervated muscle target, that offers a compelling new option for primary prevention and secondary treatment of symptomatic neuromas of the upper extremity. Here, we provide a detailed description of our surgical technique as it is applied to neuromas of the upper extremity.

Prophylactic Regenerative Peripheral Nerve Interfaces in Elective Lower Limb Amputations

Regenerative peripheral nerve interface (RPNI) is a relatively new surgical technique to manage neuromas and phantom pain after limb amputation. This study evaluates prophylactic RPNI efficacy in managing post-amputation pain and neuroma formation in amputees compared with patients in which lower limb amputation was performed without this procedure. We included 28 patients who underwent above the knee amputation (AKA) or below the knee amputation (BKA) for severe soft tissue infection from July 2019 till December 2020. All patients had insulin-dependent diabetes. The patients were divided into two groups, 14 patients with primary RPNI and 14 patients without. We analyzed the demographic data, level of amputation, number of RPNIs, operative time, postoperative complications and functional outcome on the defined follow up period. The mean patient age was 68.6 years (range 49-85), 19 (67.9 %) male and 9 (32.1 %) female patients. In this study 11 (39.3 %) AKA and 17 (60.7 %) BKA were performed. Overall, 37 RPNIs were made. The mean follow-up period was 49 weeks. PROMIS T-score decreased by 15.9 points in favor for the patients with RPNI. The VAS score showed that, in the RPNI group, all 14 patients were without pain compared to the group of patients without RPNI, where the 11 (78.6 %) patients described their pain as severe. Patients with RPNI used prosthesis significantly more (p < 0.005). Data showed significant reduction in pain and high patient satisfaction after amputation with RPNIs. This technique is oriented as to prevent neuroma formation with RPNI surgery, performed at the time of amputation. RPNI surgery did not provoke complications or significant lengthening of operative time and it should be furthermore exploited as a surgical technique.

Three-Dimensional Microfilament Printing of a Decellularized Extracellular Matrix (dECM) Bioink Using a Microgel Printing Bath for Nerve Graft Fabrication and the Effectiveness of dECM Graft Combined with a Polycaprolactone Conduit

Various synthetic and decellularized materials are being used to reconstruct peripheral nerve defects and replace autologous nerve grafts. In this study, we developed a microgel printing bath to three-dimensionally (3D) print a peripheral nervous system decellularized extracellular matrix nerve graft reinforced by a polycaprolactone (PCL) conduit. The straightforward fabrication method of an alginate microgel-supplemented printing bath allows a 30 μm filament resolution of a low viscous decellularized extracellular matrix hydrogel with neutral pH. When applied to a sciatic nerve defect model of rats, the total number of regenerated axons and relative gastrocnemius muscle weight ratio were comparable to those of the autologous nerve graft group. Meanwhile, the results were superior to those of the porcine decellularized nerve graft group or the 3D printed decellularized extracellular matrix graft group. This study will be the first step demonstrating that the 3D printed decellularized extracellular matrix (dECM) graft with a PCL conduit is an effective and reliable choice to replace an autologous nerve graft in the near future.

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.

What is Operative? Conceptualizing Neuralgia: Neuroma, Compression Neuropathy, Painful Hyperalgesia, and Phantom Nerve Pain

Neuralgia, or nerve pain, is a common presenting complaint for the hand surgeon. When the nerve at play is easily localized, and the cause of the pain is clear (eg, carpal tunnel syndrome), the patient may be easily treated with excellent results. However, in more complex cases, the underlying pathophysiology and cause of neuralgia can be more difficult to interpret; if incorrectly managed, this leads to frustration for both the patient and surgeon. Here we offer a way to conceptualize neuralgia into 4 categories-compression neuropathy, neuroma, painful hyperalgesia, and phantom nerve pain-and offer an illustrative clinical vignette and strategies for optimal management of each. Further, we delineate the reasons why compression neuropathy and neuroma are amenable to surgery, while painful hyperalgesia and phantom nerve pain are not.

Complications of Hair Transplant Procedures-Causes and Management

Hair transplant surgery per se has low risk, is relatively safe, and has minimum incidence of complications. However, it is a well-accepted fact that no medical science procedure exists without any potential risk of complications. The complication may be a single complaint in the form of pain, itching, dissatisfaction related to the procedure's outcome, or surgical complication in the form of infection, wound dehiscence or skin necrosis. Inadequate counselling increases unsatisfaction. Improper examination increases the complications, and incomplete medical history and history of allergy increases the risk during surgery.

The author collected data of his 2896 patients, operated over a period of 10 years, and recorded the complains and complications. The most common complications were sterile folliculitis, noted in 203 patients, vasovagal shock in seven patients of, hypertensive crisis in one patient, hiccups in six patients, facial edema after hair transplant in 18 patients, graft dislodgement in 8 patients, infection in two diabetic patients, minor necrotic patches in recipient area in three patients, keloid development in one patient, numbness in 18 cases, and hypersensitivity in recipient and/or donor area. Donor area effluvium was seen in one case and three patients showed recipient area effluvium. Twenty-six patients were not happy with the results, and five cases showed partial loss of implanted hair. The overall significant life-threatening or major complications were zero, but the total minor complications' percentage was 0.10%.

The key to minimize complaints and complications are detailed counselling, taking careful medical history and history of allergy, and proper examination of patients.

Stump-plasty: An Operation Born of Necessity in Gaza

Aim and objective

The most recent wave of lower limb amputees in Gaza arises from ballistic injuries sustained during protests. This study evaluates the requirement for surgical revision of these mature stumps to allow prosthetic fit and mobility.

Materials and methods

A multidisciplinary team (MDT) comprising a prosthetist, orthopaedic and plastic surgeons and a physiotherapist screened 104 amputee stumps (103 cases). The 27 cases selected for surgical revision (stump-plasty) are the subject of this study.

The MDT prescriptions of care issued at screening were compared to surgical procedures performed at stump-plasty and the findings. Compliance with the MDT prescription was recorded. Stump issues are identified to propose modifications of primary amputation technique to mitigate future revisions.

Patients’ healthcare status was assessed by questionnaire (EQ-5D-L5) at screening, then subsequently post-stump-plasty.

Results

More below-knee amputees (BKAs) than above-knee amputees (AKAs) required stump-plasty. Revisions varied according to the quality of tissue present at the amputation level. AKA revisions addressed bulk and contour issues whereas BKA revisions related to bone prominence, neuroma formation and lack of soft tissue cover. Despite many variations in tissue-targeted procedures being possible, the MDT prescription was followed accurately at surgery.

Suggested modifications at primary amputation to decrease revisions include improved bone tip bevelling at BKA and greater soft tissue reduction at AKA. Severed nerve management needs to be rationalised to reduce primary neuroma formation and neuroma revision at stump-plasty requires consideration to attempt to reduce the recurrent risk. Removal of the fibular remnant in short BKA stumps at primary amputation could mitigate common peroneal nerve hypersensitivity later.

Following stump-plasty, amputees recorded a significantly improved score in three of five dimensions of the EQ-5D-L5 questionnaire: activities, anxiety levels and pain.

Conclusion and clinical significance

Primary ballistic injury dictates the level of amputation and the resultant stump quality. Issues arising in these complex amputee stumps benefited from measured decisions and specialist care delivered by the MDT. Stump-plasty aims to improve the amputees’ prosthetic fit, mobility and health.

How to cite this article

Godwin Y, Almaqadma A, Abukhoussa H, et al. Stump-plasty: An Operation Born of Necessity in Gaza. Strategies Trauma Limb Reconstr 2021;16(2):102–109.

Clinical Outcome for Surgical Treatment of Traumatic Neuroma With a Processed Nerve Allograft: Results of a Small Prospective Case Series

Processed nerve allografts are used increasingly in the treatment of traumatic neuroma in small sensory nerves. The goal of the present study was to investigate the use of an allograft after different intervals between injury and repair and to analyze results, not only for the success of pain relief, but also for potential recovery of sensation in time. Four patients with painful neuroma in small sensory nerves in the lower extremity were surgically treated with a decellularized allograft. Patients were followed prospectively for at least 1 y. Clinical outcome was assessed using the Likert scale. Recovery of sensation was tested using Semmes-Weinstein monofilaments. In all 4 cases an allograft of 3-cm was used to reconstruct a defect in the superficial peroneal (3) or sural nerve (1) after excision of the neuroma. Complete relief of pain symptoms was achieved in 2 patients: 1 case concerned the reconstruction of a neuroma with an interval of less than 1 y between injury and repair and 1 case a neuroma-in-continuity. Sensation recovered completely in these 2 cases. In the other 2 cases, that had an interval between injury and reconstruction of more than 1 y, there was neither successful pain relief nor recovery of sensation. This prospective study shows that processed nerve allografts can be successful for the reconstruction of small sensory nerves after excision of the traumatic neuroma both for recovery of pain and sensation, but in this small case series only if the interval between injury and reconstruction was <1 y.

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.

Long Acellular Nerve Allografts Cap Transected Nerve to Arrest Axon Regeneration and Alter Upstream Gene Expression in a Rat Neuroma Model

BACKGROUND

Treatments to manage painful neuroma are needed. An operative strategy that isolates and controls chaotic axonal growth could prevent neuroma. Using long acellular nerve allograft to "cap" damaged nerve could control axonal regeneration and, in turn, regulate upstream gene expression patterns.

METHODS

Rat sciatic nerve was transected, and the distal nerve end was reversed and ligated to generate a model end-neuroma. Three groups were used to assess their effects immediately following this nerve injury: no treatment (control), traction neurectomy, or 5-cm acellular nerve allograft cap attached to the proximal nerve. Regeneration of axons from the injured nerve was assessed over 5 months and paired with concurrent measurements of gene expression from upstream affected dorsal root ganglia.

RESULTS

Both control and traction neurectomy groups demonstrated uncontrolled axon regeneration revealed using Thy1-GFP rat axon imaging and histomorphometric measures of regenerated axons within the most terminal region of regenerated tissue. The acellular nerve allograft group arrested axons within the acellular nerve allograft, where no axons reached the most terminal region even after 5 months. At 5 months, gene expression associated with regeneration and pain sensitization, including Bdnf, cfos, and Gal, was decreased within dorsal root ganglia obtained from the acellular nerve allograft group compared to control or traction neurectomy group dorsal root ganglia.

CONCLUSIONS

Long acellular nerve allografts to cap a severed nerve arrested axon regeneration within the acellular nerve allograft. This growth arrest corresponded with changes in regenerative and pain-related genes upstream. Acellular nerve allografts may be useful for surgical intervention of neuroma.

The Cutting Edge: Surface Texture Analysis following Resection of Nerve Stumps Using Various Instruments

Background:

Preparation of nerve ends is an essential part of nerve repair surgery. Multiple instruments have been described for this purpose; however, no consensus exists regarding which is the least traumatic for tissue handling. We believe that various instruments used for nerve-end excision will lead to different surface roughness.

Methods:

Median and ulnar nerves from fresh frozen cadavers were dissected, and 1–2 cm lengths were excised using a No. 11 blade, a razor blade, or a pair of scissors. Using electron microscopy, 3-dimensional surface analysis of roughness (Sa) for each specimen was performed using ZeeScan optical hardware and GetPhase software (PhaseView, Buisson, France). An ANOVA or Kruskal-Wallis test compared roughness measures among cutting techniques.

Results:

Forty nerves were included. Of these, 13 (32.5%) were cut using scissors, 15 (37.5%) using a razor blade, and 12 (30%) using a No. 11 blade. An ANOVA test showed statistical differences in Sa among the cutting techniques (P = 0.002), with the lowest mean Sa noted in the scissors group (7.2 µM, 95% CI: 5.34–9.06), followed by No. 11 blade (7.29 µM, 95% CI: 5.22–9.35), and razor blade (11.03 µM, 95% CI: 9.43–12.62). Median Ra (surface profile roughness) was 4.58 (IQR: 2.62–5.46). A Kruskal-Wallis test demonstrated statistical difference in Ra among techniques (P = 0.003), with the lowest by No. 11 blade (3 µM, IQR: 1.87–4.38), followed by scissors (3.29 µM, IQR: 1.56–4.96), and razor (5.41 µM, IQR: 4.95–6.21).

Conclusion:

This novel technique of 3-dimensional surface analysis found razor blade use demonstrated poor roughness, whereas a No. 11 blade or nerve-specific scissors led to equivocally smooth nerve ends.

Treatment of Iatrogenic Saphenous Neuroma after Knee Arthroscopy with Excision and Allograft Reconstruction

The treatment of postoperative, painful sensory neuromas is an ongoing challenge for surgeons. Here, we describe a technique for treatment with excision and allograft reconstruction and report on early results of its use in treating painful saphenous neuromas after knee arthroscopy.

Methods

A retrospective review of a single surgeon's peripheral nerve clinic from January 1, 2013, to December 31, 2019, was conducted to identify post-knee arthroscopy saphenous neuroma cases in which reconstruction with processed human nerve allograft distally implanted into healthy muscle belly was performed. We examined the outcomes for each patient, including subjective pain self-assessment and need for further surgical treatment.

Results

In total, 9 cases were identified, with patient ages ranging from 21 to 74 years. The average time to referral to peripheral nerve clinic was 31 months (range: 4-143 months). Upon exploration, all nerves were found to have a neuroma in continuity. Six of the 9 patients reported subjective improvement through final follow-up. Three of the 9 patients reported initial improvement, with recurrence of pain at/near the site of the neuroma. The average follow-up time was 9 months (range: 1-21 months).

Conclusions

Here, we report on a novel technique of using a processed human nerve allograft after neuroma resection to provide an organized environment for bridging regenerated axons into muscle tissue. We also describe our early results using this technique to treat iatrogenic saphenous neuromas after knee arthroscopy. Results are encouraging, with 6 of the 9 patients experiencing subjective reduction in pain at final follow-up.

Neuroma Management: Capping Nerve Injuries With an Acellular Nerve Allograft Can Limit Axon Regeneration

Background: Management of painful neuromas continues to challenge clinicians. Controlling axon growth to prevent neuroma has gained considerable traction. A logical extension of this idea is to therefore develop an approach to control and arrest axon growth. Given the limits in axonal regeneration across acellular nerve allografts (ANAs), these constructs could provide a means to reliably terminate axon regeneration from an injured nerve. The purpose of this study was to determine if attaching an ANA to an injured nerve could provide a means to control and limit axon regeneration in a predictable manner. Methods: Twenty (20) adult rats received a sciatic nerve transection, where only the proximal nerve was repaired using an ANA of variable length (0.5, 2.5, and 5.0 cm) or left unrepaired (control). The nerves were harvested 5 weeks post-operatively for gross and histomorphometric analysis. The extent of myelinated axons in regenerated tissue was quantified. Results: At 5 weeks, limited axon regeneration within the ANAs was observed. All lengths of ANAs lead to reduced myelinated axon numbers in the most terminal tissue region compared to untreated injured nerve (P = .002). Additionally, ANA length 2.5 cm or greater did not contain any axons at the most terminal tissue region. Conclusions: This study demonstrates a proof of concept that ANAs attached to the proximal end of an injured nerve can limit axon growth in a controlled manner. Furthermore, the extent of axon growth from the injured nerve into the ANA is dependent on the ANA length.

Targeted Muscle Reinnervation to Expendable Motor Nerves for the Treatment of Refractory Symptomatic Neuromas in Nonamputees

Symptomatic neuromas can cause debilitating pain, significantly impairing patients’ quality of life. There are numerous medical and surgical options for management. Targeted muscle reinnervation (TMR) is a nerve transfer procedure that is now commonly used to prevent or treat symptomatic neuromas or phantom limb pain in amputees. There are a few reports in the current literature about performing TMR in the nonamputee, but no cohort studies to date that report pain outcomes. This study evaluates TMR to treat symptomatic neuromas in nonamputee patients. This is a retrospective cohort study of all patients with symptomatic neuromas treated with TMR over a 1-year period from January 1,2019, to January 1, 2020, at MedStar Georgetown University Hospital. The neuromas are excised to healthy nerve fascicles, and a redundant donor motor fascicle is selected for nerve transfer. Patients were asked in clinic or via telephone about their preoperative and postoperative pain, function, and quality of life, and postoperative clinic notes were reviewed for complications and motor deficits. Fifteen patients were included in this study. Patients had symptomatic neuromas involving the upper extremity, lower extremity, and trunk. Pain frequency decreased from 6.7 times per week to 3.9 (P < 0.01) and from 9.1 times per day to 5.1 (P < 0.01). Pain severity decreased from an average of 7.9/10 to 4.3/10 (P < 0.01). Overall physical function increased from 3.7/10 to 5.8/10 (P = 0.01), and overall quality of life increased from 4.9/10 to 7.0/10 (P < 0.01). No patients had demonstrable weakness of the motor function of the donor nerve. Targeted muscle reinnervation is a viable surgical option for the treatment of symptomatic neuromas, particularly in those patients who have previously failed prior neuroma excisions.

Residual limb pain: An evidence-based review

Acquired limb loss, whether from accident or amputation, occurs with an incidence of greater than 175,000 per year in the United States. Current prevalence is estimated at greater than 1.5 million and is expected to double within 30 years. While many patients with amputations may have no significant pain or sensory issues after healing from the initial loss, one-quarter to one-half of patients may have ongoing difficulties with residual limb pain, phantom limb pain, or phantom limb sensation. This review explores the potential etiologies of those symptoms, as well as a variety of treatment options that a practitioner may consider when approaching this condition.

[Surgical management of peripheral nerves after extremity loss]

Hintergrund

Nach Verlust einer Gliedmaße ist es die Aufgabe des Chirurgen, einen möglichst schmerzfreien und belastbaren Stumpf zu formen. Hierbei kommt insbesondere an der oberen Extremität ein funktioneller Aspekt hinzu, da zur Steuerung myoelektrischer Prothesen entsprechende Muskelsignale notwendig sind. Der Umgang mit peripheren Nerven im Stumpfbereich nimmt sowohl hinsichtlich der Schmerztherapie als auch der funktionellen Mensch-Maschinen-Anbindung eine zentrale Rolle ein.

Ziel der Arbeit

Die Darstellung aktueller chirurgischer Verfahren zum Umgang mit peripheren Nerven nach Extremitätenamputation.

Material und Methoden

Es erfolgt eine Literaturrecherche bzgl. chirurgischer Prophylaxe und Therapie von Neurom- und Phantomschmerzen, sowie zu Techniken zur Verbesserung der funktionellen Schnittstelle zwischen Stumpf und Prothese. Anhand relevanter Arbeiten sowie der Erfahrungen der Autoren werden entsprechende Empfehlungen formuliert.

Ergebnisse und Diskussion

Es gibt eine große Anzahl an verschiedenen Operationstechniken, insbesondere im Umgang mit schmerzhaften Neuromen. Von den klassischen Verfahren findet besonders häufig die intramuskuläre Verlagerung der endständiger Nerven Anwendung. Neuere Techniken wie Targeted Muscle Reinnervation (TMR) und Regenerative Peripheral Nerve Interface (RPNI) zielen erstmals darauf ab, dem Nerven auch nach Amputation funktionelle Endorgane zu liefern. Neben der verbesserten Steuerung myoelektrischer Prothesen zeigen diese Verfahren auch exzellente Ergebnisse in Bezug auf Neurom- und Phantomschmerzen.

Spider silk nerve graft promotes axonal regeneration on long distance nerve defect in a sheep model

Peripheral nerve injuries with substantial tissue loss require autologous nerve transplantation or alternatively reconstruction with nerve conduits. Axonal elongation after nerve transection is about 1 mm/day. The precise time course of axonal regeneration on an ultrastructural level in nerve gap repair using either autologous or artificial implants has not been described. As peripheral nerve regeneration is a highly time critical process due to deterioration of the neuromuscular junction, this in vivo examination in a large animal model was performed in order to investigate axonal elongation rates and spider silk material degradation in a narrowly delimited time series (20, 30, 40, 50, 90, 120, 150 and 180 days) by using a novel spider silk based artificial nerve graft as a critical prerequisite for clinical translation. Autologous nerves or artificial nerve conduits based on spider silk of the spider species Trichonephila edulis were transplanted in a 6.0 cm nerve defect model in the black headed mutton. At each of the post-implant time point, electrophysiology recordings were performed to assess functional reinnervation of axonal fibers into the implants. Samples were analyzed by histology and immunofluorescence in order to verify the timeline of axonal regeneration including axonal regeneration rates of the spider silk implant and the autologous transplant groups. Spider silk was degraded within 3 month by a light immune response mainly mediated by Langhans Giant cells. In conjunction with behavioral analysis and electrophysiological measurements, the results indicate that the spider silk nerve implant supported an axonal regeneration comparable to an autologous nerve graft which is the current gold standard in nerve repair surgery. These findings indicate that a biomaterial based spider silk nerve conduit is as effective as autologous nerve implants and may be an important approach for long nerve defects.

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

Introduction Symptomatic neuroma with neuropathic pain can develop following peripheral nerve injury. Current interventions for symptomatic neuroma have unpredictable results. NEUROCAP (Polyganics, Groningen, The Netherlands) is a bioresorbable nerve capping device intended to protect a peripheral nerve end and separate the nerve from the surrounding environment, to prevent the recurrence of a symptomatic neuroma.

Materials and Methods This study aims to assess the implantation effects of the NEUROCAP device in a rat sciatic nerve model during 12 months (±2 days). Forty-one adult male Sprague-Dawley rats were used in this study. They were randomly divided into a capping or test group, or a noncapping or control group for different time points of survival (12 weeks, 6 months, and 12 months). The objective of this study was evaluated regarding procedural data, adverse events, clinical observations, and histopathology.

Results The overall general health of the animals was adequate throughout the study, with the exception of autotomy during the first 4 months of survival. Eight animals were euthanized early due to autotomy, excluded from the study and seven of them have been replaced. Autotomy was an expected outcome and a known limitation of the animal model, particularly as this was a full sciatic nerve transection model. Neuroma formation was observed in the control group while there was no neuroma formation present in the test group. The control group showed increased nerve outgrowth and more chaotic fascicles in comparison with the test group. The test group also had a higher percentage of myelinated fibers compared to the control group. These results indicate a preventive mode of action of the NEUROCAP with regard to neuroma formation after nerve transection in a rat sciatic nerve model.

Conclusion The results indicate that NEUROCAP is safe and effective in preventing the recurrence of neuroma formation and inhibiting nerve outgrowth.

Prevention of symptomatic neuroma in traumatic digital amputation: A RAND/UCLA appropriateness method consensus study

INTRODUCTION

The appearance of a symptomatic neuroma following finger amputation is a devastating consequence for patient's quality of life. It could be cause of chronic neuropathic pain. The prevention of neuroma formation is a challenging effort for hand surgeons. The biological mechanisms leading to neuroma formation are mostly unknown and different preventing procedures have been tried without certain results. In this paper, a panel of Italian hand surgeons have been asked to express appropriateness about potentially preventive techniques of neuroma formation following the RAND/UCLA appropriateness protocol.

METHODS

A literature review was preliminarily performed identifying the most employed methods to reduce the pathologic nerve scar. Afterwards, the selected panelists were asked to score the appropriateness of each procedure in a double scenario: in case of a sharp amputation or in a tear injury. The appropriateness was evaluated according to RAND/UCLA protocol.

RESULTS

Nine Italian hand surgeons were included in the panel. Of them 5 were orthopaedic surgeons, 4 plastic surgeons. The identified appropriate procedures were: revision amputation should be done in operating room, the neurovascular bundles should be identified and is mandatory to treat surrounding soft tissues. Only in case of clean-cut amputation, it is appropriate to perform a proximal extension of the dissection, to use diathermocoagulation and coverage with local flaps. Procedures such as shortening in tension of the nerve stump, bone shortening, implantation of the nerve end in the soft tissue, treatment in the emergency room and, in both scenarios, certain results are evaluated as uncertain.

DISCUSSION

In order to prevent the formation of a distal stump neuroma few methods were judged appropriate. It is mandatory to identify the neurovascular bundles and treat also the surrounding tissues, but no certain results could be obtained with local flap, bone shortening and other ancillary surgical acts. Moreover, it is not possible to guarantee the non arising of neuroma in any cases, also when every procedure has been temped.

CONLUSIONS

The prevention of distal neuroma is actually a challenge, without a well known strategy due to the variability of response of nervous tissue to injury.

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.

Targeted Muscle Reinnervation Improves Residual Limb Pain, Phantom Limb Pain, and Limb Function: A Prospective Study of 33 Major Limb Amputees

BACKGROUND

Targeted muscle reinnervation is an emerging surgical technique to treat neuroma pain whereby sensory and mixed motor nerves are transferred to nearby redundant motor nerve branches. In a recent randomized controlled trial, targeted muscle reinnervation was recently shown to reduce postamputation pain relative to conventional neuroma excision and muscle burying.

QUESTIONS/PURPOSES

(1) Does targeted muscle reinnervation improve residual limb pain and phantom limb pain in the period before surgery to 1 year after surgery? (2) Does targeted muscle reinnervation improve Patient-reported Outcome Measurement System (PROMIS) pain intensity and pain interference scores at 1 year after surgery? (3) After 1 year, does targeted muscle reinnervation improve functional outcome scores (Orthotics Prosthetics User Survey [OPUS] with Rasch conversion and Neuro-Quality of Life [Neuro-QOL])?

METHODS

Data on patients who were ineligible for randomization or declined to be randomized and underwent targeted muscle reinnervation for pain were gathered for the present analysis. Data were collected prospectively from 2013 to 2017. Forty-three patients were enrolled in the study, 10 of whom lacked 1-year follow-up, leaving 33 patients for analysis. The primary outcomes measured were the difference in residual limb and phantom limb pain before and 1 year after surgery, assessed by an 11-point numerical rating scale (NRS). Secondary outcomes were change in PROMIS pain measures and change in limb function, assessed by the OPUS Rasch for upper limbs and Neuro-QOL for lower limbs before and 1 year after surgery.

RESULTS

By 1 year after targeted muscle reinnervation, NRS scores for residual limb pain from 6.4 ± 2.6 to 3.6 ± 2.2 (mean difference -2.7 [95% CI -4.2 to -1.3]; p < 0.001) and phantom limb pain decreased from 6.0 ± 3.1 to 3.6 ± 2.9 (mean difference -2.4 [95% CI -3.8 to -0.9]; p < 0.001). PROMIS pain intensity and pain interference scores improved with respect to residual limb and phantom limb pain (residual limb pain intensity: 53.4 ± 9.7 to 44.4 ± 7.9, mean difference -9.0 [95% CI -14.0 to -4.0]; residual limb pain interference: 60.4 ± 9.3 to 51.7 ± 8.2, mean difference -8.7 [95% CI -13.1 to -4.4]; phantom limb pain intensity: 49.3 ± 10.4 to 43.2 ± 9.3, mean difference -6.1 [95% CI -11.3 to -0.9]; phantom limb pain interference: 57.7 ± 10.4 to 50.8 ± 9.8, mean difference -6.9 [95% CI -12.1 to -1.7]; p ≤ 0.012 for all comparisons). On functional assessment, OPUS Rasch scores improved from 53.7 ± 3.4 to 56.4 ± 3.7 (mean difference +2.7 [95% CI 2.3 to 3.2]; p < 0.001) and Neuro-QOL scores improved from 32.9 ± 1.5 to 35.2 ± 1.6 (mean difference +2.3 [95% CI 1.8 to 2.9]; p < 0.001).

CONCLUSIONS

Targeted muscle reinnervation demonstrates improvement in residual limb and phantom limb pain parameters in major limb amputees. It should be considered as a first-line surgical treatment option for chronic amputation-related pain in patients with major limb amputations. Additional investigation into the effect on function and quality of life should be performed.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Free muscle flap coverage as last resort for therapy-resistant neuropathic pain in the upper extremity: A long-term retrospective follow-up study

BACKGROUND

Persistent neuropathic pain severely impacts physical functioning and quality of life (QoL). However, optimal surgical management of persistent neuropathic pain remains unclear. Extensive neurolysis with subsequent free muscle flap coverage, a new surgical procedure for neuropathic pain in the upper extremity, can be performed as a final option to establish pain reduction.

METHODS

All consecutive patients who received extensive microsurgical neurolysis with subsequent free muscle flap for persistent neuropathic pain in the upper extremity between 2007 and 2014 were identified. Patient-reported upper extremity function and QoL were assessed using three questionnaires (36-item short-form health survey (SF-36), the disabilities of the arm, shoulder, and head questionnaire, and the Michigan hand outcomes questionnaire).

RESULTS

Fifteen patients were identified; 80% had neuropathic pain in the upper extremity due to nerve injury and a median of 3.0 previous surgeries (range 1-6). Sixty-seven percent developed some kind of complication, flap loss occurred in 22%, and all received a new free flap (one failed again). At last follow-up, pre- and postoperative visual analog scale (VAS) scores significantly differed (p = 0.002), and the median VAS at last follow-up was 1.5. Ten patients (67%) responded to the questionnaires after a median follow-up of 5.7 year (range 2.6-7.3 years). Patients on average reported poorer SF-36 "Physical Component Score" (PCS) and "Bodily Pain" compared to Dutch norms. Forty percent of patients reported still having always (very) severe pain. However, 64% had a postoperative decrease of at least 3.0 on VAS.

CONCLUSION

Extensive neurolysis with free muscle flap coverage for persistent neuropathic pain in the upper extremity showed a positive effect on pain reduction on short-term follow-up, and also at five-year follow-up. The impact of pain on functional outcomes remained. Nevertheless, 60% of the patients still experience sufficient pain reduction.

Chronic postoperative complications and donor site morbidity after sural nerve autograft harvest or biopsy

Background

The sural nerve is the most frequently harvested nerve autograft and is most often biopsied in the workup of peripheral neuropathy. While the complication types associated with these two procedures are well known, their clinical significance is poorly understood and there is a paucity of data regarding the complication rates.

Methods

Pubmed search identified studies regarding complications after sural nerve harvest and biopsy. The data was grouped into sensory deficits, chronic pain, sensory symptoms, wound infections, wound complications, other postoperative complications, and complications impacting daily life. The incidence of each complication was calculated, and a chi‐square analysis was performed to determine if there were any differences between nerve biopsies and graft harvest with respect to each complication.

Results

Twelve studies yielded 478 sural nerve procedures. Sensory deficits occurred at a rate of 92.9%, chronic pain at 19.7%, sensory symptoms at 41.1%, wound infections at 5.7%, noninfectious wound complications at 7.8%, and impact on daily life at 5.0%. The differences in wound infections, sensory symptoms, and impact on daily life between biopsies versus graft excisions were found to reach statistical significance (p < .05).

Conclusions

Sural nerve excisions can cause chronic postoperative donor‐site complications. Given these complications, alternative available mediums for nerve reconstruction should be explored and utilized wherever appropriate. If an alternative medium is unavailable and nerve autograft must be harvested for nerve reconstruction, then patients should be counseled about risks for developing donor site complications that may negatively affect quality of life.

Neurocap Use for the Treatment of Iatrogenic Neuropathic Pain: Preliminary Operative Results in 3 Patients

Painful neuromas are a devastating condition that is notoriously difficult to treat. The large number of techniques that have been attempted suggest that no one technique is superior. Neuromas often occur in the extremities, but iatrogenically caused pain in the head and neck area has also been described. This article describes 3 consecutive patients diagnosed with traumatic neuroma who underwent transection of the causative nerve, followed by capping of the nerve stump with a Neurocap. With a follow-up of 7 to 24 months, our results show a marked reduction in the pain scores of all 3 patients. The preliminary results indicate that this technique might be a viable treatment option for patients with a suspected neuroma in the head and neck area.

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.

Application of a Porcine Small Intestine Submucosa Nerve Cap for Prevention of Neuromas and Associated Pain

Painful neuroma formation is a common and debilitating sequela of traumatic or oncologic nerve amputations. Studies suggest that isolating transected nerve stumps within protective caps during amputation surgery or revision procedures may assist in preventing symptomatic nerve-end neuroma formation. This study evaluated the local effects of two porcine small intestine submucosa (pSIS) nerve caps of differing configurations on a terminal nerve end in an animal model. The tibial nerves of 57 Sprague Dawley rats were transected and transposed to the lateral hind leg. The nerves were treated with one of three SIS materials, including (i) a nerve cap with spiraling chambering, termed spiral nerve cap (SNC), (ii) a nerve cap with bifurcated chambers termed chambered nerve cap (CNC), or (iii) an open tube. The surgical control consisted of nerve stumps that were not treated. Overall tissue response, axonal swirling, optical density of axons, and behavioral pain response were quantified at 8 and 12 weeks postoperatively. There were no notable differences between the performance of the SNC and CNC groups. The pSIS nerve caps mitigated aberrant axonal regeneration and decreased neuroma formation and associated pain response. These findings suggest that nerve caps with internal chambers for axonal outgrowth may improve axonal alignment, therefore reducing the likelihood of symptomatic neuroma formation.

Treatment of Neuroma-induced Chronic Pain and Management of Nerve Defects with Processed Nerve Allografts

Symptomatic neuromas can cause significant chronic pain and negatively impact quality of life. Symptoms often persist despite narcotics and nonoperative interventions, which are largely ineffective. With the opioid crisis, treatments for chronic pain that limit narcotics are needed. Traditional surgical options may result in neuroma recurrence. Autograft reconstruction often results in donor-site morbidity. Processed nerve allografts facilitate axonal growth, nerve regeneration, and eliminate donor-site morbidity.

Methods

A literature review was performed to identify studies in which chronic neuroma pain was treated with excision and processed nerve allograft reconstruction. PubMed was queried, and data from the studies were grouped into treatment effective and ineffective groups. Statistical analyses were performed on these groups, and further subgroup analysis was performed on overall change of preoperative and postoperative pain scores using a paired t test.

Results

Seven studies fulfilled inclusion criteria yielding 42 patients. Greater than 90% of patients had improvement of pain postoperatively. The preoperative and postoperative pain scores could be determined for 40 patients. The mean preoperative score was 7.9, and the mean postoperative score was 3.54. These results were statistically significant using a paired t test with a P value of <0.001.

Conclusions

Chronic pain resulting from symptomatic neuromas can be treated with neuroma excision and nerve stump reconstruction with processed nerve allograft. This obviates autograft-associated donor-site morbidity and provides a platform to potentially restore sensation to the involved nerve whenever a distal nerve end is available. Addressing the root cause is an important paradigm shift for treating symptomatic neuromas.

Arterialized Posterior Interosseous Nerve Graft for Digital Neuroma

Painful neuromas are not uncommon following nerve injury, and are especially bothersome in the hand, with severe cases resulting in significant disability. Outcomes of neuroma surgery are unpredictable regardless of technique. It is recognized that optimal soft tissue environment influences nerve healing more than the specific nerve graft technique, and it is in this context, we present a novel technique of transferring a posterior interosseous nerve graft along with vascularized synovial and fat tissue based on a branch of the posterior interosseous artery to provide healthy soft tissue for nerve healing of neuroma in continuity about the hand and digits.

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.

Current State of the Surgical Treatment of Terminal Neuromas

Painful terminal neuromas resulting from nerve injury following amputation are common. However, there is currently no universally accepted gold standard of treatment for this condition. A comprehensive literature review is presented on the treatment of terminal neuromas. Four categories of terminal neuroma surgical procedures are assessed: epineurial closure; nerve transposition with implantation; neurorrhaphy, and alternate target reinnervation. Significant patient and case studies are highlighted in each section, focusing on surgical technique and patient outcome metrics. Studies presented consisted of a PubMed search for "terminal neuromas," without year limitation. The current available research supports the use of implantation into muscle for the surgical treatment of terminal neuromas. However, this technique has several fundamental flaws that limit its utility, as it does not address the underlying physiology behind neuroma formation. Regenerative peripheral nerve interfaces and targeted muscle reinnervation are 2 techniques that seem to offer the most promise in preventing and treating terminal neuroma formation. Both techniques are also capable of generating control signals which can be used for both motor and sensory prosthetic control. Such technology has the potential to lead to the future restoration of lost limb function in amputees. Further clinical research employing larger patient groups with high-quality control groups and reproducible outcome measures is needed to determine the most effective and beneficial surgical treatment for terminal neuromas. Primary focus should be placed on investigating techniques that most closely approximate the theoretically ideal neuroma treatment, including targeted muscle reinnervation and regenerative peripheral nerve interfaces.

Targeted muscle reinnervation in oncologic amputees: Early experience of a novel institutional protocol

BACKGROUND

We describe a multidisciplinary approach for comprehensive care of amputees with concurrent targeted muscle reinnervation (TMR) at the time of amputation.

METHODS

Our TMR cohort was compared to a cross-sectional sample of unselected oncologic amputees not treated at our institution (N = 58). Patient-Reported Outcomes Measurement Information System (NRS, PROMIS) were used to assess postamputation pain.

RESULTS

Thirty-one patients underwent amputation with concurrent TMR during the study; 27 patients completed pain surveys; 15 had greater than 1 year follow-up (mean follow-up 14.7 months). Neuroma symptoms occurred significantly less frequently and with less intensity among the TMR cohort. Mean differences for PROMIS pain intensity, behavior, and interference for phantom limb pain (PLP) were 5.855 (95%CI 1.159-10.55; P = .015), 5.896 (95%CI 0.492-11.30; P = .033), and 7.435 (95%CI 1.797-13.07; P = .011) respectively, with lower scores for TMR cohort. For residual limb pain, PROMIS pain intensity, behavior, and interference mean differences were 5.477 (95%CI 0.528-10.42; P = .031), 6.195 (95%CI 0.705-11.69; P = .028), and 6.816 (95%CI 1.438-12.2; P = .014), respectively. Fifty-six percent took opioids before amputation compared to 22% at 1 year postoperatively.

CONCLUSIONS

Multidisciplinary care of amputees including concurrent amputation and TMR, multimodal postoperative pain management, amputee-centered rehabilitation, and peer support demonstrates reduced incidence and severity of neuroma and PLP.

Preemptive Treatment of Phantom and Residual Limb Pain with Targeted Muscle Reinnervation at the Time of Major Limb Amputation

BACKGROUND

A majority of the nearly 2 million Americans living with limb loss suffer from chronic pain in the form of neuroma-related residual limb and phantom limb pain (PLP). Targeted muscle reinnervation (TMR) surgically transfers amputated nerves to nearby motor nerves for prevention of neuroma. The objective of this study was to determine whether TMR at the time of major limb amputation decreases the incidence and severity of PLP and residual limb pain.

STUDY DESIGN

A multi-institutional cohort study was conducted between 2012 and 2018. Fifty-one patients undergoing major limb amputation with immediate TMR were compared with 438 unselected major limb amputees. Primary outcomes included an 11-point Numerical Rating Scale (NRS) and Patient-Reported Outcomes Measurement Information System (PROMIS) pain intensity, behavior, and interference.

RESULTS

Patients who underwent TMR had less PLP and residual limb pain compared with untreated amputee controls, across all subgroups and by all measures. Median "worst pain in the past 24 hours" for the TMR cohort was 1 out of 10 compared to 5 (PLP) and 4 (residual) out of 10 in the control population (p = 0.003 and p < 0.001, respectively). Median PROMIS t-scores were lower in TMR patients for both PLP (pain intensity [36.3 vs 48.3], pain behavior [50.1 vs 56.6], and pain interference [40.7 vs 55.8]) and residual limb pain (pain intensity [30.7 vs 46.8], pain behavior [36.7 vs 57.3], and pain interference [40.7 vs 57.3]). Targeted muscle reinnervation was associated with 3.03 (PLP) and 3.92 (residual) times higher odds of decreasing pain severity compared with general amputee participants.

CONCLUSIONS

Preemptive surgical intervention of amputated nerves with TMR at the time of limb loss should be strongly considered to reduce pathologic phantom limb pain and symptomatic neuroma-related residual limb pain.

Painful Terminal Neuroma Prevention by Capping PRGD/PDLLA Conduit in Rat Sciatic Nerves

Neuroma formation after amputation as a long-term deficiency leads to spontaneous neuropathic pain that reduces quality of life of patients. To prevent neuroma formation, capping techniques are implemented as effective treatments. However, an ideal, biocompatible material covering the nerves is an unmet clinical need. In this study, biocompatible characteristics presented by the poly(D,L-lactic acid)/arginylglycylaspartic acid (RGD peptide) modification of poly{(lactic acid)-co- [(glycolic acid)-alt-(L-lysine)]} (PRGD/PDLLA) are evaluated as a nerve conduit. After being capped on the rat sciatic nerve stump in vivo, rodent behaviors and tissue structures are compared via autotomy scoring and histological analyses. The PRGD/PDLLA capped group gains lower autotomy score and improves the recovery, where inflammatory infiltrations and excessive collagen deposition are defeated. Transmission electron microscopy images of the regeneration of myelin sheath in both groups show that abnormal myelination is only present in the uncapped rats. Changes in related genes (MPZ, MBP, MAG, and Krox20) are monitored quantitative real-time polymerase chain reaction (qRT-PCR) for mechanism investigation. The PRGD/PDLLA capping conduits not only act as physical barriers to inhibit the invasion of inflammatory infiltration in the scar tissue but also provide a suitable microenvironment for promoting nerve repairing and avoiding neuroma formation during nerve recovery.

Painful Neuroma Treatment of the Supraorbital Nerve and Forehead Neurotization Using Human Cadaveric Nerve Allograft

Neuroma pain can be severe, persistent, and treatment-resistant. Forehead and scalp anesthesia is troublesome for patients. Following an iatrogenic ablative injury to the right supraorbital nerve, with subsequent painful neuroma formation, a human cadaveric nerve allograft (AxoGen, Alachua, FL) was used to restore sensation of the right forehead and treat pain. At 1-year follow-up, the patient was pain-free, and protective sensation to the right forehead was recovered with comparable static and dynamic 2-point discrimination between the injured (20 mm, 12 mm respectively) and the normal side (15 mm, 10 mm respectively). This is the first reported case of using a cadaver nerve allograft for successful direct neurotization of the skin and restoration of sensation in the upper part of the face, and for treating painful neuromas. Moreover, a brief review of the available techniques for treating neuromas of the supraorbital and supratrochlear nerves is provided.

Arthrodesis of the proximal interphalangeal joints of a hindlimb in a heifer

A two-year-old Braunvieh heifer was presented with a traumatic luxation of the second phalanx of the medial digit and concurrent subluxation of the second phalanx of the lateral digit of the right hindlimb. Closed reduction of both luxations was possible. Surgical arthrodesis was achieved using one narrow 4.5 mm three-hole equine locking compression plate for each joint. Placement of the bone plates resulted in stable arthrodesis of both proximal interphalangeal joints of the right hindlimb but there was persistent residual lameness. The heifer delivered a healthy calf but was slaughtered eight months after surgery because of varus deformity of the contralateral limb. Radio-graphs taken post-mortem revealed pronounced periosteal reactions involving both proximal interphalangeal joints and only partial bony bridging of the joint spaces.

A case of traumatic infraorbital neuroma

A 53-year-old Afghan man presented with a 12-month history of left proptosis, diplopia and facial swelling 20 years after a bomb blast injury. Magnetic resonance and computed tomography imaging revealed a well-circumscribed lesion centred within the left inferior orbit/superior maxillary sinus along with left orbital fracture. Histopathology and immunostaining of the debulked lesion were consistent with traumatic neuroma of the infraorbital nerve. Infraorbital neuromas have developed following orbital decompression surgeries but have not been reported previously following non-surgical trauma.