Current treatment concepts for neuromas-in-continuity

Current and Future Directions for Upper Extremity Amputations: Comparisons Between Regenerative Peripheral Nerve Interface and Targeted Muscle Reinnervation Surgeries

Upper extremity amputation can lead to significant functional morbidity. The main goals after amputation are to minimize pain and maintain or improve functional status while optimizing the quality of life. Postamputation pain is common and can be addressed with regenerative peripheral nerve interface surgery or targeted muscle reinnervation surgery. Both modalities are effective in treating residual limb pain and phantom limb pain, as well as improving prosthetic use. Differences in surgical technique between the 2 approaches need to be weighed when deciding what strategy may be most appropriate for the patient.

Neuroma Analysis in Humans: Standardizing Sample Collection and Documentation

INTRODUCTION

The biology of symptomatic neuromas is poorly understood, particularly the factors causing pain in human neuromas. Pain presence varies among and within individuals, with some having painful and nonpainful neuromas. To bridge these knowledge gaps, our group developed a protocol for assessing neuroma pain and collecting tissue for molecular analysis. This manuscript outlines our workflow and challenges and aims to inspire other centers to share their experiences with these tissues.

METHODS

For every included patient and collected nerve or bone tissue specimens, we perform a detailed chart review and a multifaceted analysis of pain and pain perception immediately before surgery. We collect patient-reported outcome measures (PROMs) on pain, function, and mental well-being outcomes at preoperative assessment and at the 6-month follow-up postoperatively. Before surgery, the patient is assessed once again to obtain an immediate preoperative pain status and identify potential differences in pain intensity of different neuromas. Intraoperatively, specimens are obtained and their gross anatomical features are recorded, after which they are stored in paraformaldehyde or frozen for later sample analyses. Postoperatively, patients are contacted to obtain additional postoperative PROMs.

RESULTS

A total of 220 specimens of nerve tissue have been successfully obtained from 83 limbs, comprising 95 specimens of neuromas and 125 specimens of nerves located proximal to the neuromas or from controls.

CONCLUSIONS

Our approach outlines the methods combining specimen collection and examination, including both macroscopic and molecular biological features, with PROMs, encompassing physical and psychological aspects, along with clinical metadata obtained through clinical teams and chart review.

Epidemiology, risk factors, diagnosis, and treatment of intra-abdominal traumatic neuromas - a narrative review

Traumatic neuroma (TN) is a disorganized proliferation of injured nerves arising from the axons and Schwann cells. Although TN rarely occurs in the abdominal cavity, the incidence of TN may be underestimated because of the large number of asymptomatic patients. TN can cause persistent pain, which seriously affects quality of life. TN of the biliary system can cause bile duct obstruction, leading to acute cholangitis. It is difficult to differentiate TN from malignancies or recurrence of malignancy, which results in a number of patients receiving aggressive treatment. We collected cases reports of intra-abdominal TN over the past 30 years form PubMed and cases diagnosed in our medical center over the past 20 years, which is the largest case series of intra-abdominal TN to the best of our knowledge. In this review, we discuss the epidemiology, pathophysiology, risk factors, classification, diagnosis, and management of intra-abdominal TN.

"Knowing It Before Blocking It," the ABCD of the Peripheral Nerves: Part D (Approach to the Patient With Nerve Injuries)

"Prevention is always better than cure." However, despite all precautions or preventive measures, sometimes patients develop neurodeficits due to suspected nerve injury in the perioperative period. Assessment and evaluation of the patient's symptoms can provide clues to the causative factors. Such causative factors can be corrected immediately to avoid further deterioration, or some may require further workup. The management plan for such a diagnosed nerve injury depends on the symptoms, the finding of the medical history, and the diagnostic imaging and tests. Simultaneous symptomatic relief in the form of pain medications, steroids, anti-inflammatory drugs, psychological counseling, and reassurance is essential to expedite treatment goals. Diagnosing and treating nerve injuries cannot be laid down as a straightforward part. It is a zigzag puzzle in its own right, playing with time and injury progression. Careful assessment to diagnose the extent of nerve damage plays an important role in treatment plans. It helps decide when to proceed and when to postpone, whether conservative strategies would suffice, or surgical repair would be required. Although most nerve injuries are self-limiting, some cases require surgical intervention that needs to be diagnosed early. The revolution was started by Sunderland in 1945 when he described neurosurgical techniques that drastically changed the entire scenario of nerve repairs. The ultimate effective treatment and full recovery may not be guaranteed, but attempts must be made to achieve the best results. With the patient's interests in mind, it is important to formulate a plan ensuring a good quality of life with minimal impact on their daily activities. Multifactorial nerve injury requires a multidisciplinary approach that primarily includes reassuring, psychological counseling, multimodal analgesia, and neurological and occupational consultations. This article describes the step-by-step approach known as the symptoms categorization-history taking-examination-diagnostic evaluations (SHED) approach to managing patients with peripheral nerve injuries. It also details the various modalities for diagnosing nerve injuries, sequential electrodiagnostic studies, and treatment plans depending on the type and extent of nerve injuries. It will help readers to design a treatment plan based on the patient's symptoms and evaluation results.

Post Traumatic Neuroma in Continuity of the Median Nerve in a Child: A Case Report

An 8-year-old girl suffered a wrist laceration from a sharp glass, severing the median nerve. The nerve was end-to-end repaired at the time by a pediatric orthopedic surgeon. Six months later, the girl suffered wrist pain and hyperesthesia over the previous surgical incision, significantly affecting her daily activities. Physical examination revealed a palpable mass over the median nerve with a positive Tinel sign, and the diagnosis of a painful neuroma in continuity was set. She underwent another surgery where the defective neuroma in-continuity was excised, and the median nerve was reconstructed using sural nerve cable autografts. At 18 months follow-up after the second surgery, the girl appeared with a full passive and active painless range of motion and a negative Tinel sign. This is the first case of neuroma in continuity presenting in a child in the literature, successfully managed surgically.

Direct End-to-End Neurorrhaphy for Wrist-Level Long Nerve Defect with Fixation of the Wrist in Flexion: Technique Note

Background  For a nerve gap, end-to-end neurorrhaphy would either be difficult or would include tension. The use of a nerve graft or conduit could be a solution, but it might compromise the reinnervation. We describe a method for wrist-level ulnar and/or median long nerve injury by fixing the wrist in the flexion position with K-wire (s) to make possible an end-to-end and tension-free neurorrhaphy. Patients and Methods  Two patients had wrist-level ulnar nerve injury for 2 and 3 months and nerve gaps of 2.5 cm and 3.5 cm, respectively, after the neuroma excision. K-wires were used to transfix from the radius to carpal bones, in order to keep their wrists in flexion of 45 and 65 degrees, respectively, with which the tension-free end-to-end neurorrhaphy could be achieved. The K-wires were removed in 6 weeks after surgery, and their wrists were kept in the splint for a progressive extension program. Results  Both patients were noted to have an improved claw hand deformity 4 months after the surgery. The ulnar nerve motor and sensory function could be recovered mostly in the 12-month follow-up. The wrist flexion and extension motion arc both achieved, at least, 150 degree in the 12-month follow-up. There were no complications related to the K-wire fixation. Conclusion  With the wrist fixed in a flexed position, maintaining a longer nerve gap to achieve a direct end-to-end and tension-free neurorrhaphy would be more likely and safer. Without the use of nerve graft, innervation of the injured nerve would be faster.

Target Receptors of Regenerating Nerves: Neuroma Formation and Current Treatment Options

Neuromas form as a result of disorganized sensory axonal regeneration following nerve injury. Painful neuromas lead to poor quality of life for patients and place a burden on healthcare systems. Modern surgical interventions for neuromas entail guided regeneration of sensory nerve fibers into muscle tissue leading to muscle innervation and neuroma treatment or prevention. However, it is unclear how innervating denervated muscle targets prevents painful neuroma formation, as little is known about the fate of sensory fibers, and more specifically pain fiber, as they regenerate into muscle. Golgi tendon organs and muscle spindles have been proposed as possible receptor targets for the regenerating sensory fibers; however, these receptors are not typically innervated by pain fibers, as these free nerve endings do not synapse on receptors. The mechanisms by which pain fibers are signaled to cease regeneration therefore remain unknown. In this article, we review the physiology underlying nerve regeneration, the guiding molecular signals, and the target receptor specificity of regenerating sensory axons as it pertains to the development and prevention of painful neuroma formation while highlighting gaps in literature. We discuss management options for painful neuromas and the current supporting evidence for the various interventions.

Trigeminal Traumatic Neuroma: a Comprehensive Review of the Literature Based On a Rare Case

PURPOSE OF REVIEW

Traumatic neuromas in general, and trigeminal traumatic neuromas in particular, are relatively rare entities originating from a damage to a corresponding nerve or its branches. This manuscript is a comprehensive review of the literature on trigeminal traumatic neuromas based on an interesting and challenging case of bilateral intraoral lesions.

RECENT FINDINGS

The diagnosis for this patient was bilateral trigeminal traumatic neuromas. It is possible that these patients have a genetic predisposition to the development of these lesions. It is a neuropathic pain condition and may mimic dental and other trigeminal pain entities. Topical treatment with lidocaine gel, utilizing a custom-made neurosensory stent, rendered the patient significant and sustained pain relief. Trigeminal traumatic neuromas present a diagnostic challenge even to a seasoned clinician, due to the complex clinical features that may mimic other entities. Topical medications such as local anesthetics may be a good viable alternative to systemic medications to manage the pain associated with the condition. Early identification of the lesion and the associated pain helps in the succinct management of symptomatic trigeminal traumatic neuromas.

3D MR Neurography

High-resolution isotropic volumetric three-dimensional (3D) magnetic resonance neurography (MRN) techniques enable multiplanar depiction of peripheral nerves. In addition, 3D MRN provides anatomical and functional tissue characterization of different disease conditions affecting the peripheral nerves. In this review article, we summarize clinically relevant technical considerations of 3D MRN image acquisition and review clinical applications of 3D MRN to assess peripheral nerve diseases, such as entrapments, trauma, inflammatory or infectious neuropathies, and neoplasms.

[Neuropathic Pain - Differential Diagnosis and Treatment from the Hand Surgeon's Perspective]

Neuropathic Pain - Differential Diagnosis and Treatment from the Hand Surgeon's Perspective Abstract. Neuropathic pain of the wrist and hand can be caused by a multitude of pathologies, such as trauma, iatrogenic damage, local peripheral nerve compression, nerve tumors and systemic diseases. Neuropathic pain can lead to chronification and disability, severely affecting the patients' quality of life and the ability to work. A precise diagnosis is the key to an adequate therapy with satisfactory functional results. An interdisciplinary and multimodal approach is a prerequisite when treating neuropathic pain. This review article provides an insight into the diagnosis and therapy of pathologies associated with neuropathic pain of the wrist and hand.

Regenerative Peripheral Nerve Interfaces for the Treatment and Prevention of Neuromas and Neuroma Pain

A neuroma occurs when a regenerating transected peripheral nerve has no distal target to reinnervate. This situation can result in a hypersensitive free nerve ending that causes debilitating pain to affected patients. No techniques to treat symptomatic neuromas have shown consistent results. One novel physiologic solution is the regenerative peripheral nerve interface (RPNI). RPNI consists of a transected peripheral nerve that is implanted into an autologous free skeletal muscle graft. Early clinical studies have shown promising results in the use of RPNIs to treat and prevent symptomatic neuromas. This review article describes the rationale behind the success of RPNIs and its clinical applications.

MRI features of symptomatic amputation neuromas

OBJECTIVES

To demonstrate the magnetic resonance imaging (MRI) features of amputation neuromas in lower extremity amputees and investigate independent predictive MRI features for symptomatic neuromas.

METHODS

This retrospective study included 45 amputation neuromas in 44 lower extremity amputees. Two radiologists assessed the imaging features, including shape, size, type (end-bulb or spindle), signal intensity (SI), heterogeneity, margins, enlarged fascicles, dark outer rim, tail sign, target sign, enhancement, perilesional fibrosis, and muscle denervation. The neuromas were categorized into symptomatic (n = 24) or asymptomatic (n = 21). Symptomatic neuromas were determined based on neuropathic pain characteristics, the presence of Tinel's sign or tenderness, and response to local anesthetic injection. Univariate and multivariate analyses were performed to identify independent predictive MRI features.

RESULTS

Of 45 neuromas, 80% (36/45) were end-bulb neuromas and 20% (9/45) were spindle-type neuromas. Eighty percent of the neuromas (36/45) were heterogeneous on T2-weighted images (WIs). Enlarged fascicles were present in 42% (19/45) and dark outer rims in 27% (12/45) of the neuromas. Among the 23 neuromas with enhanced images, 78% (18/23) showed enhancement. Heterogeneity on T2-WIs and enhancement ratios were significantly different between the asymptomatic and symptomatic neuroma groups (p < 0.05). The multivariate analyses indicated that heterogeneity on T2-WIs was an independent factor associated with symptomatic neuromas (p < 0.001).

CONCLUSIONS

Heterogeneity on T2-WIs could be a predictive indicator for symptomatic neuromas in lower extremity amputees.

KEY POINTS

• Amputation neuromas are classified as either end-bulb or spindle-type. They can show enlarged fascicles, dark outer rims, and enhancement. • Heterogeneity on T2-weighted images could be a predictive indicator for symptomatic neuromas. • Predicting the symptomatic neuroma on MRI would help in effective management of stump pain.

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.

Peripheral Nerve Injuries: Electrophysiology for the Neurosurgeon

Peripheral nerve injuries are a heterogeneous and distinct group of disorders that are secondary to various causes commonly including motor vehicle accidents, falls, industrial accidents, household accidents, and penetrating trauma. The earliest classification of nerve injuries was given by Seddon and Sunderland, which holds true till date and is commonly used. Neuropraxia, axonotmesis, and neurotmesis are the three main types of nerve injuries. The electrophysiological studies including nerve conduction studies (NCS) and electromyography (EMG) play a key role and are now considered an extension of the clinical examination in patients with peripheral nerve injuries. The electrophysiological results should be interpreted in the light of clinical examination. These studies help in localizing the site of lesion, determine the type and severity of lesion, and help in prognosticating. In neuropraxia, the compound muscle action potential (CMAP) and sensory nerve action potential (SNAP) are elicitable on stimulating the nerve distal to the site of the lesion but demonstrate conduction block on proximal stimulation. The electrodiagnostic findings in axonotmesis and neurotmesis are similar. After few days of injury, Wallerian degeneration sets in with failure to record CMAP and SNAP. Intraoperative technique involves recording from the peripheral nerves during the intraoperative period and has proved useful in the surgical management of nerve injuries and helps in identifying the injured nerve, to determine whether the nerve is in continuity and in localizing the site of lesion. Intraoperative monitoring also helps in identifying the nerve close to an ongoing surgery so that surgical damage to the nerve can be prevented.

Sutureless repair of a partially transected median nerve using Tisseel glue and Axoguard nerve protector: A case report

Peripheral nerve injuries in which the nerve is not completely severed often result in neuromas-in-continuity. These can cause sensory and functional deficits and must be resected and reconstructed. In defects greater than 5 mm in length, nerve graft is indicated, and suture neurorrhaphy is typically used to secure the nerve ends. However, sutures may negatively impact nerve regeneration. Fibrin glue has recently been used to mitigate the inflammatory response associated with suture neurorrhaphy. Most of the literature regarding fibrin glue covers animal models and supports its use for nerve reconstruction. Tisseel, a fibrin sealant developed as an adjunct to hemostasis, has recently shown utility in peripheral nerve repair by increasing tensile strength without additional sutures. We present the successful use of Tisseel sealant in a neuroma resection and reconstruction. In this case, a 35-year-old female presented with persistent neuropathic pain and neurologic dysfunction related to the median nerve in her hand with a history of distal forearm laceration and prior carpal tunnel release. Upon exploration, a neuroma-in-continuity involving 75% of the nerve was identified, resected, and reconstructed using processed human nerve allograft, as well as Tisseel sealant and Axoguard nerve protector to secure the repair and offload tension. At 1-year follow-up, pain was resolved, with ≤8 mm static 2-point discrimination in the median nerve distribution, and excellent improvement in hand strength compared with preoperative conditions. The outcome of this case indicates that fibrin glue may be useful to avoid excess sutures in cases of neuroma-in-continuity not involving the entire cross-section of the nerve.

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 Surgical Approach to Treat Painful Neuromas of the Supraorbital and Supratrochlear Nerves with Implantation of the Proximal Stump into the Orbit

Frontal neuralgia causally related to trauma to the supraorbital and supratrochlear nerves remains a difficult problem to resolve. A peripheral nerve approach to this problem would involve neuroma resection and relocation of the proximal nerve stump to a location away from the vulnerable supraorbital ridge. A retrospective chart review was done to identify patients with frontal pain related to supraorbital trauma who underwent operative interventions to solve this problem by neuroma resection and relocation of the proximal stumps into the orbit. Eight patients were identified for inclusion in this study. At a mean of 16 months after surgery, there was a significant change in the visual analog score from a mean of 9.4 to 2.8 ( p  < 0.05), with 88% of the patients reporting a >50% reduction in pain postoperatively. There was one treatment failure. There were no postoperative complications. The strategy of relocating the proximal end of the supraorbital and supratrochlear nerves into the posterior orbit after resecting the painful neuromas can successfully manage posttraumatic craniofacial pain related to these injured nerves.

Relocation Nerve Grafting: A Technique for Management of Symptomatic Digital Neuromas

Digital neuromas are a common problem following amputation, often severely impairing hand function. Surgical treatment of terminal digital nerve neuroma is challenging because of the lack of surrounding soft tissue in the hand. To help tackle this problem, we describe a novel technique, "relocation nerve grafting," to relocate the nerve ends into the interosseous muscles at the midcarpal level.

Relocation Nerve Grafting: A Technique for Management of Symptomatic Digital Neuromas

Digital neuromas are a common problem following amputation, often severely impairing hand function. Surgical treatment of terminal digital nerve neuroma is challenging because of the lack of surrounding soft tissue in the hand. To help tackle this problem, we describe a novel technique, "relocation nerve grafting," to relocate the nerve ends into the interosseous muscles at the midcarpal level.

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.

Time course of traumatic neuroma development

This study was designed to characterize morphologic stages during neuroma development post amputation with an eye toward developing better treatment strategies that intervene before neuromas are fully formed. Right forelimbs of 30 Sprague Dawley rats were amputated and limb stumps were collected at 3, 7, 28, 60 and 90 Days Post Amputation (DPA). Morphology of newly formed nerves and neuromas were assessed via general histology and neurofilament protein antibody staining. Analysis revealed six morphological characteristics during nerve and neuroma development; 1) normal nerve, 2) degenerating axons, 3) axonal sprouts, 4) unorganized bundles of axons, 5) unorganized axon growth into muscles, and 6) unorganized axon growth into fibrotic tissue (neuroma). At early stages (3 & 7 DPA) after amputation, normal nerves could be identified throughout the limb stump and small areas of axonal sprouts were present near the site of injury. Signs of degenerating axons were evident from 7 to 90 DPA. From day 28 on, variability of nerve characteristics with signs of unorganized axon growth into muscle and fibrotic tissue and neuroma formation became visible in multiple areas of stump tissue. These pathological features became more evident on days 60 and 90. At 90 DPA frank neuroma formation was present in all stump tissue. By following nerve regrowth and neuroma formation after amputation we were able to identify 6 separate histological stages of nerve regrowth and neuroma development. Axonal regrowth was observed as early as 3 DPA and signs of unorganized axonal growth and neuroma formation were evident by 28 DPA. Based on these observations we speculate that neuroma treatment and or prevention strategies might be more successful if targeted at the initial stages of development and not after 28 DPA.

Resection of the Posterior, Middle, and Anterior Superior Alveolar Nerves and Infraorbital Nerve Neurolysis for Refractory Maxillary Pain

Trigeminal injury can cause intractable facial pain. However, surgical approaches to the superior alveolar nerves have not been widely described. We report resection of the anterior superior alveolar nerve (ASAN), middle superior alveolar nerve (MSAN), and posterior superior alveolar nerve (PSAN) in a patient with refractory facial pain and outline an algorithmic approach to the treatment of trigeminal nerve injury. A 56-year-old woman presented with a 3-year history of refractory facial pain in the distribution of the right superior alveolar nerves after dental trauma. As a comorbidity, central sensitization developed in the patient, manifesting in the uninjured oral areas being painful. After several temporary nerve blocks and medical management, the patient underwent resection of the ASAN, MSAN, and PSAN, as well as neurolysis of the infraorbital nerve, through a Caldwell-Luc approach. One week postoperatively, she reported substantial improvement in pain symptoms, including burning and temperature sensitivity, in the right maxilla. These findings were maintained at 7 months, without any maxillary sinus complications. Central sensitization caused continued intraoral symptoms. The ASAN, MSAN, and PSAN can be surgically resected within the maxillary sinus to treat refractory neuropathic pain. An etiology-based approach can guide successful treatment of trigeminal neuropathy. Central sensitization as a comorbidity must be addressed medically.

Significance of alpha smooth muscle actin expression in traumatic painful neuromas: a pilot study in rats

Treatment of painful neuromas remains a challenge and the mechanism of neuroma-associated pain is not yet fully understood. In this study, we aimed to observe the expression of alpha smooth muscle actin (α-SMA) in traumatic neuromas and to investigate its possible roles in the cause of neuropathic pain in a rat model. The rat sciatic nerve was used and the experiment was divided into two parts. In part I, our results showed significantly higher levels of α-SMA and the pain marker c-fos in the autotomy group than in the no-autotomy group. In part II, the expression of α-SMA in neuromas was down- and up-regulated using SB-431542 and GW9662, respectively. A significant correlation between autotomy scores and the expression level of α-SMA was found (R = 0.957; p < 0.001) and the expression level of α-SMA was positively related to the autotomy scores (R² = 0.915, p < 0.001). We concluded that the expression of α-SMA plays certain roles in the neuroma-associated pain, either as a direct cause of pain or as an indirect marker of existence of local mechanical stimuli. Our findings may provide new insights into the development of new treatment modalities for the management of intractable painful neuromas.

Successful delayed reconstruction of common peroneal neuroma-in-continuity using sural nerve graft

Injuries of the common peroneal nerve (CPN) are frequent and associated with poor motor outcomes. So far, the opinion is held, that nerve reconstruction is reasonable and indicated up to 6 months after injury. We describe successful sural nerve interposition grafting in a patient with neuroma-in-continuity formation of the CPN, presenting with foot drop, 13 months after injury. Due to this positive result, we think nerve grafting in neuroma-in-continuity lesions of the CPN should be contemplated in patients with foot drop even more than one year after injury.

Peripheral nerve surgery: the role of high-resolution MR neurography

High-resolution MRN is becoming increasingly available due to recent technical advancements, including higher magnetic field strengths (eg, 3T), 3D image acquisition, evolution of novel fat-suppression methods, and improved coil design. This review describes the MRN techniques for obtaining high-quality images of the peripheral nerves and their small branches and imaging findings in normal as well as injured nerves with relevant intraoperative correlations. Various microsurgical techniques in peripheral nerves, such as neurolysis, nerve repairs by using nerve grafts, and conduits are discussed, and MRN findings of surgically treated nerves are demonstrated.

Traumatic neuroma in continuity injury model in rodents

Traumatic neuroma in continuity (NIC) results in profound neurological deficits, and its management poses the most challenging problem to peripheral nerve surgeons today. The absence of a clinically relevant experimental model continues to handicap our ability to investigate ways of better diagnosis and treatment for these disabling injuries. Various injury techniques were tested on Lewis rat sciatic nerves. Optimal experimental injuries that consistently resulted in NIC combined both intense focal compression and traction forces. Nerves were harvested at 0, 5, 13, 21, and 65 days for histological examination. Skilled locomotion and ground reaction force (GRF) analysis were performed up to 9 weeks on the experimental (n=6) and crush-control injuries (n=5). Focal widening, disruption of endoneurium and perineurium with aberrant intra- and extrafascicular axonal regeneration and progressive fibrosis was consistently demonstrated in 14 of 14 nerves with refined experimental injuries. At 8 weeks, experimental animals displayed a significantly greater slip ratio in both skilled locomotor assessments, compared to nerve crush animals (p<0.01). GRFs of the crush- injured animals showed earlier improvement compared to the experimental animals, whose overall GRF patterns failed to recover as well as the crush group. We have demonstrated histological features and poor functional recovery consistent with NIC formation in a rat model. The injury mechanism employed combines traction and compression forces akin to the physical forces at play in clinical nerve injuries. This model may serve as a tool to help diagnose this injury earlier and to develop intervention strategies to improve patient outcomes.

The double crush syndrome revisited--a Delphi study to reveal current expert views on mechanisms underlying dual nerve disorders

A high prevalence of dual nerve disorders is frequently reported. How a secondary nerve disorder may develop following a primary nerve disorder remains largely unknown. Although still frequently cited, most explanatory theories were formulated many years ago. Considering recent advances in neuroscience, it is uncertain whether these theories still reflect current expert opinion. A Delphi study was conducted to update views on potential mechanisms underlying dual nerve disorders. In three rounds, seventeen international experts in the field of peripheral nerve disorders were asked to list possible mechanisms and rate their plausibility. Mechanisms with a median plausibility rating of ≥7 out of 10 were considered highly plausible. The experts identified fourteen mechanisms associated with a first nerve disorder that may predispose to the development of another nerve disorder. Of these fourteen mechanisms, nine have not previously been linked to double crush. Four mechanisms were considered highly plausible (impaired axonal transport, ion channel up or downregulation, inflammation in the dorsal root ganglia and neuroma-in-continuity). Eight additional mechanisms were listed which are not triggered by a primary nerve disorder, but may render the nervous system more vulnerable to multiple nerve disorders, such as systemic diseases and neurotoxic medication. Even though many mechanisms were classified as plausible or highly plausible, overall plausibility ratings varied widely. Experts indicated that a wide range of mechanisms has to be considered to better understand dual nerve disorders. Previously listed theories cannot be discarded, but may be insufficient to explain the high prevalence of dual nerve disorders.

The painful neuroma and the use of conduits

Treatment of neuromas in the foot and ankle is evolving. A paucity of studies deals with neuromas in this region; most knowledge comes from hand surgery. A trend toward reconstructive surgery using nerve grafts and conduits for nerves with critical function is being seen. For noncritical nerves, generally accepted treatment is neuroma resection and burial into a tissue bed. A clear knowledge of neural anatomy is paramount, together with correct identification of all the nerves involved in the pain-generation process. More studies dealing with neuromas in this area are needed for evidence-based information.

MR neurography of neuromas related to nerve injury and entrapment with surgical correlation

MR imaging of peripheral nerves has been described in relation to abnormalities such as nerve injury, entrapment, and neoplasm. Neuroma formation is a known response to peripheral nerve injury, and here we correlate the MRN appearance of postinjury neuroma formation with intraoperative findings. We also present the MR imaging features of surgical treatment with a synthetic nerve tube and nerve wrap on postoperative follow-up imaging.