How electrodiagnosis predicts clinical outcome of focal peripheral nerve lesions

Assessment, management, and rehabilitation of traumatic peripheral nerve injuries for non-surgeons

Electrodiagnostic evaluation is often requested for persons with peripheral nerve injuries and plays an important role in their diagnosis, prognosis, and management. Peripheral nerve injuries are common and can have devastating effects on patients' physical, psychological, and socioeconomic well-being; alongside surgeons, electrodiagnostic medicine specialists serve a central function in ensuring patients receive optimal treatment for these injuries. Surgical intervention-nerve grafting, nerve transfers, and tendon transfers-often plays a critical role in the management of these injuries and the restoration of patients' function. Increasingly, nerve transfers are becoming the standard of care for some types of peripheral nerve injury due to two significant advantages: first, they shorten the time to reinnervation of denervated muscles; and second, they confer greater specificity in directing motor and sensory axons toward their respective targets. As the indications for, and use of, nerve transfers expand, so too does the role of the electrodiagnostic medicine specialist in establishing or confirming the diagnosis, determining the injury's prognosis, recommending treatment, aiding in surgical planning, and supporting rehabilitation. Having a working knowledge of nerve and/or tendon transfer options allows the electrodiagnostic medicine specialist to not only arrive at the diagnosis and prognosticate, but also to clarify which nerves and/or muscles might be suitable donors, such as confirming whether the branch to supinator could be a nerve transfer donor to restore distal posterior interosseous nerve function. Moreover, post-operative testing can determine if nerve transfer reinnervation is occurring and progress patients' rehabilitation and/or direct surgeons to consider tendon transfers.

Combat-related peripheral nerve injuries

Active-duty service members (ADSM) and military Veterans represent a population with increased occupational risk for nerve injuries sustained both during training operations and wartime. Mechanisms of war-related nerve injuries have evolved over time, from the musket ball-related traumas described by S.W. Mitchell to complex blast injuries and toxic exposures sustained during Middle East conflicts in the 21st century. Commonly encountered nerve injury etiologies in this population currently include compression, direct trauma, nutritional deficits, traumatic limb amputation, toxic chemical exposures, or blast-related injuries. Expeditious identification and comprehensive, interdisciplinary treatment of combat-associated neuropathies, as well as prevention of these injuries whenever possible is critical to reduce chronic morbidity and disability for service members and to maintain a well-prepared military. However, diagnosis of a combat-associated nerve injury may be particularly challenging due to comorbid battlefield injuries or delayed presentation of neuropathy from military toxic exposures. Advances in imaging for nerve injury, including MRI and ultrasound, provide useful tools to compliment EMG in establishing a diagnosis of combat-associated nerve injury, particularly in the setting of anatomic disruption or edema. Surgical techniques can improve pain control or restoration of function. In all cases, comprehensive interdisciplinary rehabilitation provides the best framework for optimization of recovery. Further work is needed to prevent combat-associated nerve injuries and promote nerve recovery following injury.

Serial electrodiagnostic testing: Utility and indications in adult neurological disorders

Although existing guidelines address electrodiagnostic (EDX) testing in identifying neuromuscular conditions, guidance regarding the uses and limitations of serial (or repeat) EDX testing is limited. By assessing neurophysiological change longitudinally across time, serial electrodiagnosis can clarify a diagnosis and potentially provide valuable prognostic information. This monograph presents four broad indications for serial electrodiagnosis in adult peripheral neurological disorders. First, where clinical change has raised suspicion for a new or ongoing lesion, EDX reassessment for spatial spread of abnormality, involvement of previously normal muscle or nerve, and/or evolving pathophysiology can clarify a diagnosis. Second, where diagnosis of a progressive neuromuscular condition is uncertain, electrophysiological data from a second time point can confirm or refute suspicion. Third, to establish prognosis after a static nerve injury, a repeat study can assess the presence and extent of reinnervation. Finally, faced with a limited initial study (as when complicated by patient or environmental factors), a repeat EDX study can supplement missing or limited data to provide needed clarity. Repeat EDX studies carry certain limitations, however, such as with prognostication in the setting of remote or chronic lesions, sensory predominant fascicular injury, or mild axonal injury. Nevertheless, serial electrodiagnosis remains a valuable and underused tool in the diagnostic and prognostic evaluation of neuromuscular conditions.

The role of electrodiagnosis in focal neuropathies

Electrodiagnostic (EDX) testing plays an important role in confirming a mononeuropathy, localizing the site of nerve injury, defining the pathophysiology, and assessing the severity and prognosis. The combination of nerve conduction studies (NCS) and needle electromyography findings provides the necessary information to fully assess a nerve. The pattern of NCS abnormalities reflects the underlying pathophysiology, with focal slowing or conduction block in neuropraxic injuries and reduced amplitudes in axonotmetic injuries. Needle electromyography findings, including spontaneous activity and voluntary motor unit potential changes, complement the NCS findings and further characterize chronicity and degree of axon loss and reinnervation. EDX is used as an objective marker to follow the progression of a mononeuropathy over time.

Slimmer's Palsy Following Weight Loss Associated With Metastatic Breast Cancer: A Case Report

Common peroneal neuropathy (CPN), also known as Slimmer's Palsy, is an isolated peripheral neuropathy typically associated with rapid weight loss resulting in loss of adipose tissue and subsequent nerve compression at the fibular head and is up to three times more common in individuals with malignancy. In this case report, we describe the diagnosis of CPN in a 54-year-old female with a 2.5-month history of atraumatic left foot drop and left ankle paresthesias, preceded by a 35-40 pound weight loss over the prior 3.5 month period in the setting of metastatic breast cancer.

Ulnar neuropathy

Ulnar neuropathy at the elbow is the second most common compressive neuropathy. Less common, although similarly disabling, are ulnar neuropathies above the elbow, at the forearm, and the wrist, which can present with different combinations of intrinsic hand muscle weakness and sensory loss. Electrodiagnostic studies are moderately sensitive in diagnosing ulnar neuropathy, although their ability to localize the site of nerve injury is often limited. Nerve imaging with ultrasound can provide greater localization of ulnar injury and identification of specific anatomical pathology causing nerve entrapment. Specifically, imaging can now reliably distinguish ulnar nerve entrapment under the humero-ulnar arcade (cubital tunnel) from nerve injury at the retro-epicondylar groove. Both these pathologies have historically been diagnosed as either "ulnar neuropathy at the elbow," which is non-specific, or "cubital tunnel syndrome," which is often erroneous. Natural history studies are few and limited, although many cases of mild-moderate ulnar neuropathy at the elbow appear to remit spontaneously. Conservative management, perineural steroid injections, and surgical release have all been studied in treating ulnar neuropathy at the elbow. Despite this, questions remain about the most appropriate management for many patients, which is reflected in the absence of management guidelines.

Assessment, patient selection, and rehabilitation of nerve transfers

Peripheral nerve injuries are common and can have a devastating effect on physical, psychological, and socioeconomic wellbeing. Peripheral nerve transfers have become the standard of care for many types of peripheral nerve injury due to their superior outcomes relative to conventional techniques. As the indications for, and use of, nerve transfers expand, the importance of pre-operative assessment and post-operative optimization increases. There are two principal advantages of nerve transfers: (1) their ability to shorten the time to reinnervation of muscles undergoing denervation because of peripheral nerve injury; and (2) their specificity in ensuring proximal motor and sensory axons are directed towards appropriate motor and sensory targets. Compared to conventional nerve grafting, nerve transfers offer opportunities to reinnervate muscles affected by cervical spinal cord injury and to augment natural reinnervation potential for very proximal injuries. This article provides a narrative review of the current scientific knowledge and clinical understanding of nerve transfers including peripheral nerve injury assessment and pre- and post-operative electrodiagnostic testing, adjuvant therapies, and post-operative rehabilitation for optimizing nerve transfer outcomes.

Obturator Nerve Injury in Robotic Pelvic Surgery: Scenarios and Management Strategies

BACKGROUND

Obturator nerve injury (ONI) is an uncommon complication of pelvic surgery, usually reported in 0.2-5.7% of cases undergoing surgical treatment of urological and gynecological malignancies involving pelvic lymph node dissection (PLND).

OBJECTIVE

To describe how an ONI may occur during robotic pelvic surgery and the corresponding management strategies.

DESIGN, SETTING, AND PARTICIPANTS

We retrospectively analyzed video content on intraoperative ONI provided by robotic surgeons from high-volume centers.

SURGICAL PROCEDURE

ONI was identified during PLND and managed according to the type of nerve injury.

RESULTS AND LIMITATIONS

The management approach varies with the type of injury. Crush injury frequently occurs at an advanced stage of PLND. For a crush injury to the obturator nerve caused by a clip, management only requires its safe removal. Three situations can occur if the nerve is transected: (1) transection with feasible approximation and tension-free nerve anastomosis; (2) transection with challenging approximation requiring certain strategies for proper nerve anastomosis; and (3) transection with a hidden proximal nerve ending that may initially appear intact, but is clearly injured when revealed by further dissection. Each case has different management strategies with a common aim of prompt repair of the anatomic disruption to restore proper nerve conduction.

CONCLUSIONS

ONI is a preventable complication that requires proper identification of the anatomy and high-risk areas when performing pelvic lymph node dissection. Prompt intraoperative recognition and repair using the management strategies described offer patients the best chance of recovery without sequelae.

PATIENT SUMMARY

We describe the different ways in which the obturator nerve in the pelvic area can be damaged during urological or gynecological surgeries. This is a preventable complication and we describe how it can be avoided and different management options, depending on the type of nerve injury.

Value of ultrasound assessment for traumatic nerve injury of the upper limb

Aim of work

The type of traumatic peripheral nerve injury is a key factor for determining optimal treatment. Proper assessment of peripheral nerve injury facilitates appropriate treatment, significantly affects prognosis, and reduces disabilities. This study evaluated ultrasonography (US) to assess upper limb traumatic nerve injuries and compared the US with electrodiagnostic studies as the gold standard.

Materials and Methods

Participants were 69 adults (57 [83%] men, 12 [17%] women; mean age 36.3 ± 13.5 years) with a total of 96 peripheral nerve injuries (duration of 1 month–3 years). High-frequency US examinations and electro-physiologic studies confirmed upper limb peripheral nerve injury.

Results

Nerve discontinuation was diagnosed in 15 (15.6%) nerves; the cross-sectional area was increased in 33 (34.4%) nerves. Of 96 injuries, 54 (56.3%) were median, 24 (25%) were ulnar, and 18 (18.8%) were radial nerves. No statistically significant difference was found between US and electro-physiologic studies for nerve injury diagnosis (p = 0.054).

Conclusion

No significant differences were found between US and electro-physiologic studies for diagnosis of nerve injuries; however, US was valuable to assess surrounding tissue and supplied muscles. The capabilities to detect nerve injury and associated distal muscular, vascular, and other regional structures position the US as a complementary diagnostic tool.

Traumatic injury to peripheral nerves

This article reviews the epidemiology, classification, localization, prognosis, and mechanisms of recovery of traumatic peripheral nerve injuries (PNIs). Electrodiagnostic (EDx) assessments are critical components of treating patients with PNIs. In particular, motor and sensory nerve conduction studies, needle electromyography, and other electrophysiological methods are useful for localizing peripheral nerve injuries, detecting and quantifying the degree of axon loss, and contributing toward treatment decisions as well as prognostication. It is critical that EDx medical consultants are aware of the timing of these changes as well as limitations in interpretations. Mechanisms of recovery may include recovery from conduction block, muscle fiber hypertrophy, distal axonal sprouting, and axon regrowth from the site of injury. Motor recovery generally reaches a plateau at 18 to 24 months postinjury. When patients have complete or severe nerve injuries they should be referred to surgical colleagues early after injury, as outcomes are best when nerve transfers are performed within the first 3 to 6 months after onset.

Traumatic peripheral nerve injuries: diagnosis and management

PURPOSE OF REVIEW

To review advances in the diagnostic evaluation and management of traumatic peripheral nerve injuries.

RECENT FINDINGS

Serial multimodal assessment of peripheral nerve injuries facilitates assessment of spontaneous axonal regeneration and selection of appropriate patients for early surgical intervention. Novel surgical and rehabilitative approaches have been developed to complement established strategies, particularly in the area of nerve grafting, targeted rehabilitation strategies and interventions to promote nerve regeneration. However, several management challenges remain, including incomplete reinnervation, traumatic neuroma development, maladaptive central remodeling and management of fatigue, which compromise functional recovery.

SUMMARY

Innovative approaches to the assessment and treatment of peripheral nerve injuries hold promise in improving the degree of functional recovery; however, this remains a complex and evolving area.

Peripheral Nerve Injury After Upper-Extremity Surgery Performed Under Regional Anesthesia: A Systematic Review

Purpose

Peripheral nerve injury (PNI) is a known adverse event following upper-limb surgery performed under brachial plexus regional anesthesia (RA). When PNI is noted after surgery, patients and providers often have questions about which factors might have contributed to this complication. This systematic review evaluates the literature on hand and shoulder surgeries performed under ultrasound-guided, plexus RA to identify factors potentially associated with PNI, including the surgery location and block type. We hypothesized that shoulder surgery might be associated with an increased risk of PNI compared to hand surgery.

Methods

A systematic review of the relevant literature was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Only prospective studies on the use of ultrasound-guided, preoperative, brachial plexus RA for hand or shoulder surgery on adult patients were included. Study groups were categorized according to surgery location and block type and compared across a number of factors via univariate and multivariate analyses.

Results

A total of 3,037 abstracts were screened; 192 full-text articles were independently reviewed by 2 of the authors; and 53 studies were included in the systematic review analysis. Following hand surgery, PNI was reported at an average rate of 1.35% ± 3.21% across 836 subjects in 40 study groups; after shoulder surgery, the average rate was 0.50% ± 1.57% across 3,383 subjects in 15 study groups. There was no statistically significant correlation between the incidence of PNI and surgery location (P =.70) or any of the most common approaches for brachial plexus anesthesia in the multivariate analysis.

Conclusions

This systematic review of over 50 articles on upper-limb surgery performed under RA shows no association between the incidence of PNI and the location of surgery or type of brachial plexus block.

Type of study/level of evidence

Diagnostic II.

Pre-operative electrodiagnostic planning for upper limb peripheral nerve transfers in cervical spinal cord injury: A Narrative Review

Peripheral nerve transfer (PNT) to improve upper limb function following cervical spinal cord injury (SCI) involves the transfer of supralesional donor nerves under voluntary control to intralesional or sublesional lower motor neurons not under voluntary control. Appropriate selection of donor and recipient nerves and surgical timing impact functional outcomes. While the gold standard of nerve selection is intra-operative nerve stimulation, preoperative electrodiagnostic (EDX) evaluation may help guide surgical planning. Currently there is no standardized preoperative EDX protocol. This study reviews the EDX workup preceding peripheral nerve transfer surgery in cervical SCI, and proposes an informed EDX protocol to assist with surgical planning. The PICO (Population, Intervention, Comparison, Outcome) framework was used to formulate relevant MeSH terms and identify published cases of PNT in cervical SCI in Medline, Embase, CINAHL, and Emcare databases in the last 10 years. The electrodiagnostic techniques evaluating putative donor nerves, recipient nerve branches, time-sensitivity of nerve transfer and other electrophysiological parameters were summarized to guide creation of a preoperative EDX protocol. Needle electromyography (EMG) was the most commonly used EDX technique to identify healthy donor nerves. Although needle EMG has also been used on recipient nerves, compound muscle action potential (CMAP) amplitudes may provide a more accurate determination of recipient nerve health and time-sensitivity for nerve transfer. While there has been progress in pre-surgical EDX evaluation, EMG and NCS approaches are quite variable, and each has limitations in their utility for pre-operative planning. There is need for standardization in the EDX evaluation preceding peripheral nerve transfer surgery to assist with donor and recipient nerve selection, surgical timing and to optimize outcomes. Based on results of this review, herein we propose the PreSCIse (PRotocol for Electrodiagnosis in SCI Surgery of the upper Extremity) pre-operative EDX panel to achieve said goals through an interdisciplinary and patient-centered approach. This article is protected by copyright. All rights reserved.

SOP – N. fibularis-Parese – Fallfuß

Der akut aufgetretene Fallfuß ist meist Folge einer Läsion des N. fibularis oder einer Wurzelläsion L5. Mit der klinischen Untersuchung und der Myografie kann die Differenzialdiagnose geklärt werden. Die SOP gibt einen Vorschlag zur rationalen Stufendiagnostik.

Incidence, Risk Factors, Prevention, and Management of Peripheral Nerve Injuries Following Shoulder Arthroplasty

In this article, the authors review the incidence and causes of iatrogenic peripheral nerve injuries following shoulder arthroplasty and provide preventative measures to decrease nerve injury rate and management options. They describe common direct and indirect causes of injury such as laceration and retractor use versus arm positioning and lengthening, respectively. Preventative measures include an understanding of anatomy and high-risk locations in the shoulder, minimizing extreme ranges of arm motion and utilization of intraoperative nerve monitoring. Lastly, the authors review diagnosis and management of neurologic symptoms including how and when to use electrodiagnostic studies, nerve grafts, transfers, or muscle/tendon transfers.

[Functional reconstruction in traumatic paralysis]

BACKGROUND

Traumatic nerve injuries are associated with a high morbidity and long rehabilitation times. The extent of a nerve lesion and the related regeneration potential can often only be estimated during the course, whereby the time window for successful surgical interventions is limited.

OBJECTIVE

The incidence and distribution of traumatic nerve lesions are reported. Algorithms for treatment decisions are presented.

MATERIAL AND METHODS

Statistics from the German TraumaRegister DGU® as well as international registers were evaluated. The results of basic research and expert recommendations for diagnostics and treatment are discussed.

RESULTS AND CONCLUSION

A strategic approach to conservative and surgical treatment of traumatic nerve injuries depending on the extent of injury and resulting regeneration potential is recommended. In conjunction with the clinical course, electrophysiology and imaging diagnostics, e.g. nerve sonography, can help to differentiate between neurapraxia, axonotmesis and neurotmesis.

Role of electrodiagnosis in nerve transfers for focal neuropathies and brachial plexopathies

Over the past 2 decades, the surgical treatment of brachial plexus and peripheral nerve injuries has advanced considerably. Nerve transfers have become an important surgical tool in addition to nerve repair and grafting. Electrodiagnosis has traditionally played a role in the diagnosis and localization of peripheral nervous system injuries, but a different approach is needed for surgical decision-making and monitoring recovery. When patients have complete or severe injuries they should be referred to surgical colleagues early after injury, as outcomes are best when nerve transfers are performed within the first 3 to 6 mo after onset. Patients with minimal recovery of voluntary activity are particularly challenging, and the presence of a few motor unit action potentials in these individuals should be interpreted on the basis of timing and evidence of ongoing reinnervation. Evaluation of potential recipient and donor muscles, as well as redundant muscles, for nerve transfers requires an individualized approach to optimize the chances of a successful surgical intervention. Anomalous innervation takes on new importance in these patients. Communication between surgeons and electrodiagnostic medicine specialists (EMSs) is best facilitated by a joint collaborative clinic. Ongoing monitoring of recovery post-operatively is critical to allow for decision making for continued surgical and rehabilitation treatments. Different electrodiagnostic findings are expected with resolution of neurapraxia, distal axon sprouting, and axonal regrowth. As new surgical techniques become available, EMSs will play an important role in the assessment and treatment of these patients with severe nerve injuries.

Iatrogenic lesions of the peripheral nervous system in orthopaedic surgery and traumatology procedures

OBJECTIVE

To describe iatrogenic lesions of the peripheral nervous system and their relationship with different orthopaedic and traumatological procedures, through their assessment by means of electromyographic study.

MATERIAL AND METHODS

Retrospective descriptive study of the electromyographies performed in the clinical neurophysiology service of the Hospital General Universitari de Castelló between July 2015 and March 2019, recovering those in which the aetiology was diagnosed as iatrogenic in relation to surgical procedures and analysing those that were initiated after orthopaedic and traumatological procedures.

RESULTS

Of the total number of electromyographies reviewed, 1.37% corresponded to iatrogenic surgical lesions and 55.1% of these were secondary to orthopaedic surgery and traumatology procedures, the incidence in relation to the procedures performed was 0.65%. The most frequent locations related to injuries were the lumbar spine, hip and hand/wrist. Injuries due to postural causes not directly related to the surgical field are noteworthy.

CONCLUSION

Iatrogenic injuries to the peripheral nervous system after orthopaedic surgery and traumatology procedures are infrequent, but given their mechanism of injury and the high severity of most of them, it would be advisable to implement corrective mechanisms to reduce their incidence.

LEVEL OF EVIDENCE

IV.

Prevention and Treatment of Nerve Injuries in Shoulder Arthroplasty

➤

Nerve injuries during shoulder arthroplasty have traditionally been considered rare events, but recent electrodiagnostic studies have shown that intraoperative nerve trauma is relatively common.

➤

The brachial plexus and axillary and suprascapular nerves are the most commonly injured neurologic structures, with the radial and musculocutaneous nerves being less common sites of injury.

➤

Specific measures taken during the surgical approach, component implantation, and revision surgery may help to prevent direct nerve injury. Intraoperative positioning maneuvers and arm lengthening warrant consideration to minimize indirect injuries.

➤

Suspected nerve injuries should be investigated with electromyography preferably at 6 weeks and no later than 3 months postoperatively, allowing for primary reconstruction within 3 to 6 months of injury when indicated. Primary reconstructive options include neurolysis, direct nerve repair, nerve grafting, and nerve transfers.

➤

Secondary reconstruction is preferred for injuries presenting >12 months after surgery. Secondary reconstructive options with favorable outcomes include tendon transfers and free functioning muscle transfers.

Lower Motor Neuron Abnormality in Chronic Cervical Spinal Cord Injury: Implications for Nerve Transfer Surgery

Nerve transfer surgery (NT) constitutes an exciting option to improve upper limb functions in chronic spinal cord injury (SCI), but requires intact sublesional lower motor neuron (LMN) health. The purpose of this study was to characterize patterns of LMN abnormality in nerve-muscle groups that are the potential recipients of NT, using a standardized electrodiagnostic examination, in individuals with chronic SCI (injury duration >2 years, injury levels C4-T1). The LMN abnormality was determined using a semihierarchical approach, combining the amplitude compound muscle action potential (CMAP) and abnormal spontaneous activity on needle electromyography (EMG). Ten participants (46 potential recipient muscles) were included (median age, 42.5 years; six males and four females; median duration from injury, 15.5 years). A high frequency of LMN abnormality was observed (87%), although there was substantial variation within and between individuals. No statistically significant discordance was observed between LMN abnormality on CMAP and EMG (p = 0.24), however, 50% of muscles with normal CMAP demonstrated abnormal spontaneous activity. The high frequency of LMN abnormality in recipient nerve-muscle groups has implications to candidate selection for NT surgery in chronic SCI and supports the important role of the pre-operative electrodiagnostic examination. Our results further support the inclusion of both CMAP and needle EMG parameters for characterization of LMN health. Although the number of nerve-muscle groups with normal LMN health was small (13%), this underscores the neurophysiological potential of some patients with chronic injuries to benefit from NT surgery.

Iatrogenic lesions of the peripheral nervous system in orthopaedic surgery and traumatology procedures

OBJECTIVE

To describe iatrogenic lesions of the peripheral nervous system and their relationship with different orthopaedic and traumatological procedures, through their assessment by means of electromyographic study.

MATERIAL AND METHODS

Retrospective descriptive study of the electromyographies performed in the clinical neurophysiology service of the Hospital General Universitari de Castelló between July 2015 and March 2019, recovering those in which the aetiology was diagnosed as iatrogenic in relation to surgical procedures and analysing those that were initiated after orthopaedic and traumatological procedures.

RESULTS

Of the total number of electromyographies reviewed, 1.37% corresponded to iatrogenic surgical lesions and 55.1% of these were secondary to orthopaedic surgery and traumatology procedures, the incidence in relation to the procedures performed was 0.65%. The most frequent locations related to injuries were the lumbar spine, hip and hand/wrist. Injuries due to postural causes not directly related to the surgical field are noteworthy.

CONCLUSION

Iatrogenic injuries to the peripheral nervous system after orthopaedic surgery and traumatology procedures are infrequent, but given their mechanism of injury and the high severity of most of them, it would be advisable to implement corrective mechanisms to reduce their incidence.

LEVEL OF EVIDENCE

IV.

Nerve Ultrasound in Traumatic and Iatrogenic Peripheral Nerve Injury

Peripheral nerve injury is a potentially debilitating disorder that occurs in an estimated 2–3% of all patients with major trauma, in a similar percentage of medical procedures. The workup of these injuries has traditionally been clinical, combined with electrodiagnostic testing. However, this has limitations, especially in the acute phase of the trauma or lack of any recovery, when it is very important to determine nerve continuity and perform surgical exploration and repair in the case of the complete transection or intraneural fibrosis. Ultrasound can help in those situations. It is a versatile imaging technique with a high sensitivity of 93% for detecting focal nerve lesions. Ultrasound can assess the structural integrity of the nerve, neuroma formation and other surrounding abnormalities of bone or foreign bodies impeding the nerve. In addition, this can help to prevent iatrogenic nerve injury by marking the nerve before the procedure. This narrative review gives an overview of why and how nerve ultrasound can play a role in the detection, management and prevention of peripheral nerve injury.

Traumatic Injuries to the Spinal Cord and Peripheral Nervous System

Both blunt and penetrating trauma can cause injuries to the peripheral and central nervous systems. Emergency providers must maintain a high index of suspicion, especially in the setting of polytrauma. There are 2 major classifications of peripheral nerve injuries (PNIs). Some PNIs are classically associated with certain traumatic mechanisms. Most closed PNIs are managed conservatively, whereas sharp nerve transections require specialist consultation for urgent repair. Spinal cord injuries almost universally require computed tomography imaging; some require emergent magnetic resonance imaging. Providers should work to minimize secondary injury. Surgical specialists are needed for closed reduction, surgical decompression, or stabilization.

[The interdisciplinary diagnostics and treatment of peripheral nerve lesions]

Nerve lesions are a frequent and often neglected problem in the daily routine of hospitals and clinical work and necessitate an intensive interdisciplinary treatment. In addition to correct anatomical allocation, the correct timing of the appropriate diagnostics, the timely decision for a possible intervention and the appropriate accompanying treatment are important prerequisites for a favorable prognosis. The basic diagnostics are, above all, neurography and electromyography after a sound clinical examination and documentation. In recent years both high-resolution ultrasound imaging and magnetic resonance imaging (MRI) of nerves have increasingly become established as indispensable diagnostic tools. In addition to describing the electrophysiological and sonographic principles, this article provides insights into surgical procedures, interdisciplinary cooperation and practical approaches.

Role of nerve ultrasound versus electrophysiological studies in the evaluation of nerve injuries

Background

High-resolution ultrasonography (US) is a non-invasive, readily applicable imaging modality capable of depicting real-time static and dynamic information concerning the peripheral nerves and their surrounding tissues. Although electrophysiological studies are the gold standard in the evaluation of nerve injuries, US can be used also to evaluate the morphological changes of nerve injuries.

Objectives

To evaluate the role of the high-resolution US in the assessment of nerve injuries and to compare it to the role of electrodiagnostic studies.

Subjects and methods

A total of 30 nerves from 22 consecutive patients with clinically definite nerve injury were considered. Two independent and blinded clinicians perform electrodiagnosis and US. The clinical, neurophysiological, and US findings were collected, and the contribution of US was then classified as “ contributive” or “non-contributive”, according to whether US confirmed the clinical and neurophysiological diagnosis or not.

Results

US was “contributive” (confirming the electrophysiological diagnosis) in 66.67% of cases (n = 20), providing information about continuity of the nerve, morphological changes after injury as swelling, scar tissue formation, or neuroma formation with sensitivity of 75% compared to the electrodiagnostic studies and accuracy of 66.67%.

Conclusion

Ultrasound can be used, when available, as a complementary tool for electrodiagnostic studies to provide anatomical information about the injured nerves in case of complete axonal lesion.

Brachial and lumbosacral plexopathies: A review

Diseases of the brachial and lumbosacral plexus are uncommon and complex. The diagnosis of plexopathies is often challenging for the clinician, both in terms of localizing a patient's symptoms to the plexus as well as determining the etiology. The non-specific clinical features and similar presentations to other root, nerve, and non-neurologic disorders emphasize the importance of a high clinical index of suspicion for a plexopathy and comprehensive clinical evaluation. Various diagnostic tests, including electrodiagnostic (EDX) studies, neuroimaging (including ultrasound, MRI, or PET), serologic studies, and genetic testing, may be used to confirm a plexopathy and assist in identifying the underlying etiology. EDX testing plays an important role in confirming a plexopathy defining the localization, pathophysiology, chronicity, severity, and prognosis. Given the complexity of the plexus anatomy, multiple common and uncommon NCS and an extensive needle examination is often required, and a comprehensive, individualized approach to each patient is necessary. Treatment of plexopathies often focuses on symptomatic management although, depending on the etiology, specific targeted treatments may improve outcome. This article reviews the clinical features, EDX approaches, and evaluation and treatment of brachial and lumbosacral plexopathies.

Nerve high-resolution ultrasonography in peripheral nerve injuries associated with supracondylar humeral fractures in children

To evaluate nerve high-resolution ultrasonography (HRUS) as diagnostic tool in children with supracondylar humeral fractures (SHF)-related peripheral nerve injuries (PNIs), we selected at least one illustrative case for each upper limb nerve usually involved in SHF (i.e. median, radial and ulnar nerve), in which HRUS evaluation added a useful contribution in diagnostic and therapeutic choices. We selected four patients (3 males, 1 female, aged between 7 and 12 years). Involved nerves were median (2), radial (1) and ulnar (1). HRUS results can actively modify the management of children with SHF-related PNIs, especially when combined with clinical and EDX. HRUS should be used routinely in evaluation of children with SHF-related PNIs.

Obturator nerve injury and repair during laparoscopic lymphadenectomy. Case report and review of the literature

Objective

To report a case of obturator nerve injury during laparoscopic lymphadenectomy and repair through the same approach during the same surgical procedure; and to present a review of the literature on this type of injury, techniques used, timing of the repair, and rehabilitation outcomes.

Materials and Methods

Case presentation of a 29-year-old woman seen at the National Cancer Institute (Instituto Nacional de Cancerología) in Bogotá, Colombia. The patient had a clinical diagnosis of stage Ib1 squamous cell carcinoma of the cervix and was taken to radical trachelectomy plus bilateral pelvic lymphadenectomy because of her wish to preserve fertility. During the procedure, a complete dissection of the obturator nerve was recognized and repaired immediately through the laparoscopic approach. A literature search was conducted in the Medline database via PubMed. The terms used for the search were "Obturator Nerve," "Lymph Node Excision," "Trauma," "Nervous System". The search was limited to publications in Spanish and English and included case series and reports, cohorts and review articles published between 1968 and September 2018.

Results

Eight studies were included, all of them case reports. In six cases, complete sectioning of the nerve was recognized during surgery. In four cases, end-to-end anastomosis was used for repair; three cases were reconstructed using sural nerve grafting; and one case was managed with neurolysis and end-to-end anastomosis. All cases were approached laparoscopically. Over a nine-month follow-up period, three patients recovered full nerve function.

Conclusion

The studies retrieved were all case reports, the most frequent injury being complete nerve sectioning. Several nerve repair techniques were used. Recovery after one year was not complete in a significant number of the cases reported.

Convergent end-to-end neurorrhaphy: An alternative technique for dual innervation of the gastrocnemius muscle in rats

INTRODUCTION

Muscle contraction generated by electrical impulses simultaneously originating from two different neural sources may be an interesting treatment alternative for long term facial palsy. An experimental model was designed to compare single and dual innervation of the gastrocnemius muscle (GM) in rats.

METHODS

Fifty adult Wistar rats underwent transection of their right peroneal nerve and were divided into five groups (n = 10): control (C), tibial nerve section (TS), tibial nerve primary end-to-end neurorrhaphy (PEE), tibial nerve primary repair associated with end-to-side peroneal-to-tibial nerve transfer (PRES), and tibial nerve repair by convergent end-to-end (CEE) neurorrhaphy between the proximal stumps of the tibial and peroneal nerves to the distal stump of the tibial nerve. The outcomes were assessed 12 weeks after the experiment by walking track, electromyography, GM mass index, and histomorphometric analysis of the distal tibial nerve.

RESULTS

The functional recovery of the PRES (-33.77 ± 24.13) and CEE (-42.15 ± 31.14) groups was greater (P < 0.003) than the PEE group (-80.26 ± 17.20). The CEE group (18.35 ± 7.84) showed greater amplitude (P = 0.006) than the PEE group (8.2 ± 4.64). There was no difference in the muscle mass index among the reinnervation groups (P > 0.705). Histologic analysis revealed greater (P < 0.002) axonal density in the CEE group (126.70 ± 15.01) compared to PEE (99.70 ± 12.82) and PRES (92.00 ± 19.17) groups.

CONCLUSIONS

The dual innervation techniques showed earlier and greater functional recovery of the GM than did the single innervation technique. The CEE group showed a 40% higher number of regenerated axons in the distal tibial nerve stump.

Common Entrapment Neuropathies

PURPOSE OF REVIEW

This article addresses relevant peripheral neuroanatomy, clinical presentations, and diagnostic findings in common entrapment neuropathies involving the median, ulnar, radial, and fibular (peroneal) nerves.

RECENT FINDINGS

Entrapment neuropathies are a common issue in general neurology practice. Early diagnosis and effective management of entrapment mononeuropathies are essential in preserving limb function and maintaining patient quality of life. Median neuropathy at the wrist (carpal tunnel syndrome), ulnar neuropathy at the elbow, radial neuropathy at the spiral groove, and fibular neuropathy at the fibular head are among the most frequently encountered entrapment mononeuropathies. Electrodiagnostic studies and peripheral nerve ultrasound are employed to help confirm the clinical diagnosis of nerve compression or entrapment and to provide precise localization for nerve injury. Peripheral nerve ultrasound demonstrates nerve enlargement at or near sites of compression.

SUMMARY

Entrapment neuropathies are commonly encountered in clinical practice. Accurate diagnosis and effective management require knowledge of peripheral neuroanatomy and recognition of key clinical symptoms and findings. Clinical diagnoses may be confirmed by diagnostic testing with electrodiagnostic studies and peripheral nerve ultrasound.

Common peripheral nerve injuries in sport: diagnosis and management

Peripheral nerve injuries are unusual in sport but impact an athlete's safe return to play. Nerve injuries result from either acute trauma (most commonly in contact/collision sports) or from repetitive microtrauma and overuse. Diagnosis of overuse nerve injuries includes nerve localization and surrounding soft-tissue anatomy, and must account for possible causes of repetitive microtrauma, including biomechanics, equipment, training schedule, and recovery. Prognosis is related to the type of nerve injury. Management should not simply be rest and gradual return to sport but should address biomechanical and training predispositions to injury. Understanding the type of injury and the tissues involved will guide appropriate rehabilitation decisions. Recognizing acute care considerations and implementing appropriate strategies can help minimize secondary trauma to an area following acute injury.

Optimization of Surgical Outcome in Lower Extremity Nerve Decompression Surgery

BACKGROUND

There is still debate regarding whether the surgical release of entrapped lower extremity nerves reduces complaints of associated neuropathy and results in gain of sensory function. The aim of this study was to investigate which factors are associated with a favorable surgical outcome, by follow-up of patients previously participating in a randomized controlled trial.

METHODS

The authors evaluated the 5-year follow-up of diabetic patients previously participating in the Lower Extremity Nerve Entrapment Study (LENS). Visual analogue pain scores, satisfaction, complaints, quality of life (i.e., 36-Question Short-Form Health Survey and EuroQol 5 Dimensions instrument), sensory function, and incident ulceration and amputation were assessed. Differences between patients who underwent unilateral versus bilateral decompressions were investigated.

RESULTS

Thirty-one of the original 42 LENS participants were measured, of which eight patients underwent additional decompression of the contralateral leg, after 12-month LENS follow-up. At 5 years, bilateral surgical patients (n = 8) had significantly lower pain scores and higher quality of life compared with unilateral surgical patients (n = 23), were younger, had a lower age when diagnosed with diabetes, and had a lower body mass index at baseline. Pain scores of the additional decompressed leg decreased in a manner similar to that of the initial decompressed leg during follow-up. Patients with severe preoperative sensory loss did worse; 41.2 percent of the LENS Follow-Up Study subjects underwent or considered undergoing contralateral surgery.

CONCLUSION

The authors' results suggest that the beneficial effects of lower extremity nerve decompression surgery are reserved for a select group of patients, of which preoperative nerve damage, age, duration of diabetes, and body mass index are important effect modifiers.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Clinical and biometrical 12-month follow-up in patients after reconstruction of the sural nerve biopsy defect by the collagen-based nerve guide Neuromaix

Many new strategies for the reconstruction of peripheral nerve injuries have been explored for their effectiveness in supporting nerve regeneration. However only a few of these materials were actually clinically evaluated and approved for human use. This open, mono-center, non-randomized clinical study summarizes the 12-month follow-up of patients receiving reconstruction of the sural nerve biopsy defect by the collagen-based nerve guide Neuromaix. Neuromaix was implanted as a micro-structured, two-component scaffold bridging 20–40 mm nerve defects after sural nerve biopsy in twenty patients (eighteen evaluated, two lost in follow-up). Safety of the material was evaluated by clinical examination of wound healing. Performance was assessed by sensory testing of modalities, pain assessment, and palpation for the Hoffmann–Tinel’s sign as well as demarcating the asensitive area at each follow-up visit. Every patient demonstrated uneventful wound healing during the complete 12-month time course of the study. Two patients reported complete return of sensation, whereas eleven out of eighteen patients reported a positive Hoffmann–Tinel’s sign at the lower leg with simultaneous reduction of the asensitive area by 12 months. Our data show that Neuromaix can be implanted safely in humans to bridge sural nerve gaps. No procedure-related, adverse events, or severe adverse events were reported. These first clinical data on Neuromaix provide promising perspectives for the bridging of larger nerve gaps in combined nerves, which should be investigated more through extensive, multi-center clinical trials in the near future.

Experimental study of brachial plexus and vessel compression: evaluation of combined central and peripheral electrodiagnostic approach

Introduction

We sought to investigate the reliability of a new electrodiagnostic method for identifying Electrodiagnosis of Brachial Plexus & Vessel Compression Syndrome (BPVCS) in rats that involves the application of transcranial electrical stimulation motor evoked potentials (TES-MEPs) combined with peripheral nerve stimulation compound muscle action potentials (PNS-CMAPs).

Results

The latencies of the TES-MEP and PNS-CMAP were initially elongated in the 8-week group. The amplitudes of TES-MEP and PNS-CMAP were initially attenuated in the 16-week group. The isolateral amplitude ratio of the TES-MEP to the PNS-CMAP was apparently decreased, and spontaneous activities emerged at 16 weeks postoperatively.

Materials and Methods

Superior and inferior trunk models of BPVCS were created in 72 male Sprague Dawley (SD) rats that were divided into six experimental groups. The latencies, amplitudes and isolateral amplitude ratios of the TES-MEPs and PNS-CMAPs were recorded at different postoperative intervals.

Conclusions

Electrophysiological and histological examinations of the rats’ compressed brachial plexus nerves were utilized to establish preliminary electrodiagnostic criteria for BPVCS.

Nerve injuries of the upper extremity and hand

A nerve injury has a profound impact on the patient’s daily life due to the impaired sensory and motor function, impaired dexterity, sensitivity to cold as well as eventual pain problems.

To perform an appropriate treatment of nerve injuries, a correct diagnosis must be made, where the injury is properly classified, leading to an optimal surgical approach and technique, where timing of surgery is also important for the outcome.

Knowledge about the nerve regeneration process, where delicate processes occur in neurons, non-neuronal cells (i.e. Schwann cells) and other cells in the peripheral as well as the central nervous systems, is crucial for the treating surgeon.

The surgical decision to perform nerve repair and/or reconstruction depends on the type of injury, the condition of the wound as well as the vascularity of the wound.

To reconnect injured nerve ends, various techniques can be used, which include both epineurial and fascicular nerve repair, and if a nerve defect is caused by the injury, a nerve reconstruction procedure has to be performed, including bridging the defect using nerve-grafts or nerve transfer techniques.

The patients must be evaluated properly and regularly after the surgical procedure and appropriate rehabilitation programmes are useful to improve the final outcome.

Cite this article: EFORT Open Rev 2017;2. DOI: 10.1302/2058-5241.2.160071. Originally published online at www.efortopenreviews.org

Impact of smoking and preoperative electrophysiology on outcome after open carpal tunnel release

BACKGROUND

The aim was to evaluate the influence of smoking and preoperative electrophysiology on the outcome of open carpal tunnel release.

METHODS

This retrospective observational study evaluated the outcome in 493 patients (531 hands) primary operated for carpal tunnel syndrome. Data were collected from medical records, health evaluations, and QuickDASH questionnaires before surgery and 1 year after.

RESULTS

Smokers had a higher QuickDASH score preoperatively as well as postoperatively, but the change in total score did not differ. The odds of having a postoperative QuickDASH score >10 were 2.5 times higher in smoking patients than in non-smoking patients. In 124/493 patients (25%), no clinically significant improvement was seen. Normal and extreme preoperative electrophysiology values were associated with higher postoperative scores. No correlation was found between preoperative QuickDASH scores and preoperative electrophysiology values.

CONCLUSIONS

Smokers with carpal tunnel syndrome experience more symptoms preoperatively. Smokers have remaining symptoms after surgery. There is no correlation between preoperative QuickDASH scores and preoperative electrophysiology values. Patients with normal or near to normal preoperative electrophysiology results have limited improvement after surgery.

The relationship between sensory latency and amplitude

PURPOSE

To prove that the relationship between sensory latencies and amplitudes is useful in determining the severity of neuropathies. This is achieved by deriving a mathematical relationship between sensory distal latency and amplitude. Determine whether sensory amplitudes below predicted correlate with a worse pathology.

PROCEDURES

Patients seen for Nerve Conduction Studies by the Department of Physical Medicine and Rehabilitation at Cooper University Hospital between 12/1/12 and 12/31/14 were invited to participate in a prospective database. The median, ulnar and sural sensory latencies and amplitudes were analyzed with both linear and power regression. Patients with amplitudes above and below the regression curve were compared for latency, amplitude and velocity of other nerves. Carpal Tunnel Patients were analyzed to determine whether Median sensory amplitude below predicted correlated with more severe disease.

RESULTS

For the Median nerve, Power Regression Analysis showed a stronger correlation (R²=0.54) than linear regression (R²=0.34). Patients with Median sensory amplitude below the power correlation curve showed significantly longer ulnar sensory latency, and lower sensory amplitude than those above. Carpal Tunnel Syndrome patients with Median sensory amplitude well below predicted by the power relationship showed more advanced disease. For the ulnar and sural sensory nerve, the difference between power and linear regression was not significant.

CONCLUSIONS

A power regression curve correlates sensory latency and amplitude better than linear regression. The latency amplitude relationship correlates with other parameters of nerve function and severity of Carpal Tunnel Syndrome. This implies that below predicted sensory amplitude may indicate worse disease, and could be a useful diagnostic tool.