Sciatic and tibial neuropathies.

The sciatic nerve is the body's largest peripheral nerve. Along with their two terminal divisions (tibial and fibular), their anatomic location makes them particularly vulnerable to trauma and iatrogenic injuries. A thorough understanding of the functional anatomy is required to adequately localize lesions in this lengthy neural pathway. Proximal disorders of the nerve can be challenging to precisely localize among a range of possibilities including lumbosacral pathology, radiculopathy, or piriformis syndrome. A correct diagnosis is based upon a thorough history and physical examination, which will then appropriately direct adjunctive investigations such as imaging and electrodiagnostic testing. Disorders of the sciatic nerve and its terminal branches are disabling for patients, and expert assessment by rehabilitation professionals is important in limiting their impact. Applying techniques established in the upper extremity, surgical reconstruction of lower extremity nerve dysfunction is rapidly improving and evolving. These new techniques, such as nerve transfers, require electrodiagnostic assessment of both the injured nerve(s) as well as healthy, potential donor nerves as part of a complete neurophysiological examination.

Targeted muscle reinnervation in bionic upper limb reconstruction: current status and future directions.

Selective nerve transfers are used in the setting of upper limb amputation to improve myoelectric prosthesis control. This surgical concept is referred to as targeted muscle reinnervation (TMR) and describes the rerouting of the major nerves of the arm onto the motor branches of the residual limb musculature. Aside from providing additional myosignals for prosthetic control, TMR can treat and prevent neuroma pain and possibly also phantom limb pain. This article reviews the history and current applications of TMR in upper limb amputation, with a focus on practical considerations. It further explores and identifies technological innovations to improve the man-machine interface in amputation care, particularly regarding implantable interfaces, such as muscle electrodes and osseointegration. Finally, future clinical directions and possible scientific avenues in this field are presented and critically discussed.

Brachial plexus birth injury: advances and controversies.

While there is considerable spontaneous recovery in most cases of brachial plexus birth injury, many children are left with significant problems that may lead to lifelong functional limitations, loss of work and social isolation. Detailed treatment with the right strategy can provide very valuable improvement in function. Over the past few years, the clinical approach to brachial plexus birth palsy has entered a new era in both diagnostic and surgical treatment methods. This article reviews four areas of management, the role of imaging in defining the severity of the injury, the optimal timing of for nerve exploration and reconstruction in appropriate cases, the advantages and potential complications of nerve transfers, and the role of physiotherapy. Available evidence is considered. Although it is difficult to make clear and precise inferences on a subject where there are many variables and considerable uncertainties, some currently accepted views will be summarized.Level of evidence: V.

Adult traumatic brachial plexus injuries: advances and current updates.

Nerve grafting, tendon transfer and joint fusion are routinely used to improve the upper limb function in patients with brachial plexus palsies. Newer techniques have been developed that provide additional options for reconstruction. Nerve transfer is a tool for restoring upper limb function in total root avulsions where nerve grafting is not possible. In partial brachial plexus injuries, nerve transfers can greatly improve shoulder, elbow, wrist and hand function. Intraoperative electrical stimulation can be used to diagnose precisely which nerve is injured and to choose which nerve fascicles should be transferred. Finally, measuring the postoperative outcome can improve the evaluation of our techniques. The aim of this article was to present the current techniques used to treat patients with brachial plexus injury.

Clinical Outcomes of "Paralyzed" Nerve Transfer for Treating Spinal Cord Injury: A Proof of Concept in a Human Model.

Functional electrical stimulation (FES) is an option to restore function in individuals after high cervical spinal cord injury (SCI) who have limited available options for tendon or nerve transfer. To be considered for FES implantation, patients must possess upper motor neuron (UMN) type denervation in potential recipient muscles, which can be confirmed by response to surface electrical stimulation during clinical evaluation. Lower motor neuron (LMN) denervated muscles will not respond to electrical stimulation and, therefore, are unavailable for use in an FES system. Previous animal studies have demonstrated that a "paralyzed" nerve transfer of a UMN-denervated motor branch to an LMN-denervated motor branch can restore electrical excitability in the recipient. In this study, we report the indications, surgical technique, and successful outcome (restoration of M3 elbow flexion) after the first "paralyzed" nerve transfer in a human patient.

Surgical management of peroneal nerve injuries.

BACKGROUND: Traumatic peroneal nerve injuries are typically associated with high-energy injuries. The aim of this study was to evaluate the demographics and outcomes following surgical management of peroneal nerve injuries. METHODS: Patients evaluated at a single institution with peroneal nerve injuries between 2001 and 2022 were retrospectively reviewed. Mechanism of injury, time to surgery, pre- and postoperative examinations, and operative reports were recorded. Satisfactory outcome, defined as the ability to achieve anti-gravity dorsiflexion strength or stronger following surgery, was compared between nerve grafting and nerve transfers in patients with at least 9 months of postoperative follow-up. RESULTS: Thirty-seven patients had follow-up greater than 9 months after surgery, with an average follow-up of 3.8 years. Surgeries included neurolysis (n=5), direct repair (n=2), tibial motor nerve fascicle transfer to the anterior tibialis motor branch (n=18), or interposition nerve grafting using sural nerve autograft (n=12). At last follow-up, 59.5% (n=22) of patients had anti-gravity strength or stronger dorsiflexion. Nineteen (51.4%) patients used an ankle-foot orthosis during all or some activities. In patients that underwent nerve grafting only across the peroneal nerve defect, 44.4% (n=4) were able to achieve anti-gravity strength or stronger dorsiflexion. In patients that had a tibial nerve fascicle transfer to the tibialis anterior motor branch of the peroneal nerve, 42.9% (n=6) were able to achieve anti-gravity strength or stronger dorsiflexion at last follow-up. There was no statistical difference between nerve transfers and nerve grafting in postoperative dorsiflexion strength (p = 0.51). CONCLUSION: Peroneal nerve injuries frequently occur in the setting of knee dislocations and similar high-energy injuries. Nerve surgery is not universally successful in restoration of ankle dorsiflexion, with one-third of patients requiring an ankle-foot orthosis at mid-term follow-up. Patients should be properly counseled on the treatment challenges and variable outcomes following peroneal nerve injuries.

Detailed Management of Brachial Plexus Birth Injuries: The Miami Protocol at Nicklaus Children's Hospital.

The management of children with brachial plexus birth injuries is complex and requires a multidisciplinary approach. In the following article, we describe our approach to evaluation and management at Nicklaus Children's Hospital. It is our aim is to elucidate nuances in management.

The Philadelphia Shriners Hospital Approach to Brachial Plexus Birth Injury.

The care of children with brachial plexus birth injuries (BPBI) is a complex multidisciplinary endeavor. At the Shriners Hospital for Children in Philadelphia, we have sought to elevate the quality of care delivered to patients through outcomes research and collaboration with colleagues around the world. Our approach to the management of this challenging pathology has evolved time and again. Here, we describe our current approach to patient assessment and operative management in patients with BPBI and its many sequelae.

Management of Brachial Plexus Birth Palsies: The Stanford Experience.

The start of Stanford's brachial plexus birth palsy (BPBP) experience dates back to 1983, when Dr. Vincent Rod Hentz visited Dr. Alain Gilbert on sabbatical. Since then, our principles of care for patients with BPBP have evolved based on our group's longitudinal experience caring for children with the entire spectrum of sequelae that arise in children with BPBP. We base our clinical decision making on frequent serial examinations and use intraoperative evoked potentials to guide surgical decisions. Here, we discuss our current principles on surgical indications, timing of surgery, and preferred techniques for secondary surgery in patients with BPBP.

Resect, rewire, and restore: Nerve transfer salvage of neurological deficits associated with soft tissue tumors in a retrospective cohort series at a tertiary reconstructive center.

AIMS: We aimed to explore the effectiveness of nerve transfer as an intervention to restore neurological deficits caused by extremity tumors through direct nerve involvement, neural compression, or as a consequence of oncological surgery. METHODS: A retrospective cohort study of consecutive cases was conducted, including all patients who underwent nerve transfers to restore functional deficits in limbs following soft tissue tumor resection. The threshold for a successful nerve transfer was a BMRC motor grade of 4/5 and sensory grade of 3-3+/4 with protective sensation. RESULTS: In total, 29 nerve transfers (25 motor and 4 sensory) were completed in 11 patients, aged 12-70 years at referral, over a 6-year period to 2020. This included 22 upper limb and 3 lower limb motor nerve transfers. The timing of delayed nerve transfer reconstructions was 1-15 months following primary oncological resection, with immediate simultaneous reconstructions performed in 4 cases. The threshold for success was achieved in 82% of upper limb and 33% of lower limb motor nerve transfers, while all sensory transfers were successful in restoring protective sensation. CONCLUSION: Nerve transfer surgery, a well-established technique in restoring deficits following traumatic nerve injury, is further demonstrably relevant in extremity oncological reconstruction, especially as it can be performed remotely to the tumor location or resection site and introduces a healthy nerve or fascicle to rapidly reinnervate distal muscles without sacrificing major function. This study further illustrates the importance of early recognition and referral to specialist services where multi-disciplinary surgical resection and reconstructive planning can be conducted. LEVEL OF EVIDENCE: IV Clinical Case Series.

Spinal Cord Injury: Epidemiology, Spontaneous Recovery, and Hand Therapy for the Reconstructive Hand Surgeon.

People with spinal cord injury (SCI) prioritize hand function above all else as a reconstructive goal, yet remain a markedly undertreated population by hand surgeons. This review article provides an overview of the epidemiology of SCI and the unmet clinical need of these patients. Further, this article outlines the natural history of SCI, including the expected spontaneous recovery over time and the expectations of hand function when treated with hand therapy alone. This review aims to equip reconstructive hand surgeons with a sound understanding of the basic principles of SCI and recovery and provide a rationale for when to intervene with surgery. In the last decade, this field has changed dramatically with the advent of reliable nerve transfers, making referral and surgical intervention time-sensitive. Therefore this review aims to highlight the expectations from hand therapy alone in this group, the urgent need for early referral to allow nerve transfer options to be viable, and the strategies for overcoming the barriers to these referrals. This offers the opportunity for surgeons to expand their tetraplegia practices while maximizing the considerable contributions to the hand function and quality of life of these patients.

Distal Nerve Transfer to Restore Wrist and Finger Extension - A Systematic Review.

Background: There are numerous options available for restoration of wrist and finger extension following radial nerve palsy. The aim of this study is to conduct a systematic review of the effectiveness of nerve transfer for radial nerve palsy. Methods: Electronic literature research of PubMed, Cochrane, Scopus and Lilacs database was conducted in June 2021 using the terms 'Distal nerve transfer' AND 'Radial nerve injury' 'Radial nerve palsy' OR 'Radial nerve paresis' OR 'Median nerve transfer' OR 'wrist extensor' OR 'finger extension' OR 'thumb extension' OR 'wrist motion'. The data extracted included the study details, demographic data, procedure performed and final functional outcome according to the muscle research council scale. Results: A total of 92.59% and 56.52% had satisfactory outcome following distal nerve transfer of median nerve to restore wrist and finger extension respectively. No significant correlation was found between time to injury duration and satisfactory outcomes. Conclusions: Outcomes of nerve transfers are comparable to tendon transfers. Multi-centric studies are needed to compare the results amongst various surgical procedures described. Level of Evidence: Level III (Therapeutic).

A Case of an Ulnar Nerve Laceration With Distal Humerus Fracture From Machete Trauma.

Ulnar nerve dysfunction following distal humerus fractures is a recognized phenomenon. There is no dominating consensus regarding the optimal management of the ulnar nerve during surgical intervention for these fractures between leaving the nerve in situ versus nerve transposition for better healing. Additional complexities arise in the case we present, in which there was an open fracture compounded with an ulnar nerve laceration from a traumatic injury with a machete knife. We review and discuss the management of ulnar nerve injuries associated with complex open fractures of the humerus for optimizing patient outcomes following these injuries.

Nerve transfers in the forearm: potential use in spastic conditions.

PURPOSE: Deformities of the spastic upper limb result frequently from the association of spasticity, muscle contracture and muscle imbalance between strong spastic muscles and weak non-spastic muscles. This study was designed to evaluate the feasibility of combining selective neurectomy of the usual spastic and strong muscles together with transfer of their motor nerves to the usual weak muscles, to improve wrist and fingers motion while decreasing spasticity. METHODS: Twenty upper limbs from fresh frozen human cadavers were dissected. All motor branches of the radial and median nerve for the forearm muscles were identified. We attempted all possible end-to-end nerve transfers between the usually strong "donor" motor branches, namely FCR and PT, and the usually weak "recipient" motor branches (ERCL, ECRB, PIN, AIN). RESULTS:  The PT had two nerve branches in 80%, thus allowing selective neurectomy. The proximal PT branch could be anastomosed end-to-end in 45% (AIN) to 85% (ECRL) of cases with the potential recipient branches. The distal PT branch could be anastomosed end to end to all potential recipient nerves. The FCR had a single branch in all cases. End-to-end anastomosis was possible in 90% for the ECRL and in 100% for all other recipient branches, but sacrificed all FCR innervation, ruling out hyperselective neurectomy. CONCLUSION:  Selective neurectomies can be associated with distal nerve transfers at the forearm level in selected cases. The motor nerve to the PT is the best donor for nerve transfer combined with selective neurectomy, transferred to the ECRL, ECRB, PIN or AIN.

Lesiones del plexo braquial en adultos: una revisión narrativa de la literatura / Brachial plexus injuries in adults: a narrative review of the literature

La patología traumática del plexo braquial comprende un amplio espectro de lesiones potencialmente devastadoras para la funcionalidad de los pacientes. El objetivo del presente trabajo es realizar una revisión narrativa de la literatura enfocada en el diagnóstico y estudio de las lesiones del plexo braquial en adultos, además de entregar nociones básicas sobre el manejo de esta compleja patología

Traumatic brachial plexus injuries comprise a wide spectrum of lesions that are potentially devastating to the functionality of the patients. The aim of the present review is to perform a narrative review of the literature focused on the diagnosis and study of brachial plexus injuries in adults, in addition to providing basic guidelines on the management of this complex pathology.

Spinal motor neuron transplantation to enhance nerve reconstruction strategies: Towards a cell therapy.

Nerve transfers have become a powerful intervention to restore function following devastating paralyzing injuries. A major limitation to peripheral nerve repair and reconstructive strategies is the progressive, fibrotic degeneration of the distal nerve and denervated muscle, eventually precluding recovery of these targets and thus defining a time window within which reinnervation must occur. One proven strategy in the clinic has been the sacrifice and transfer of an adjacent distal motor nerve to provide axons to occupy, and thus preserve (or "babysit"), the target muscle. However, available nearby nerves are limited in severe brachial plexus or spinal cord injury. An alternative and novel proposition is the transplantation of spinal motor neurons (SMNs) derived from human induced pluripotent stem cells (iPSCs) into the target nerve to extend their axons to occupy and preserve the targets. These cells could potentially be delivered through minimally invasive or percutaneous techniques. Several reports have demonstrated survival, functional innervation, and muscular preservation following transplantation of SMNs into rodent nerves. Advances in the generation, culture, and differentiation of human iPSCs now offer the possibility for an unlimited supply of clinical grade SMNs. This review will discuss the previous reports of peripheral SMN transplantation, outline key considerations, and propose next steps towards advancing this approach to clinic. Stem cells have garnered great enthusiasm for their potential to revolutionize medicine. However, this excitement has often led to premature clinical studies with ill-defined cell products and mechanisms of action, particularly in spinal cord injury. We believe the peripheral transplantation of a defined SMN population to address neuromuscular degeneration will be transformative in augmenting current reconstructive strategies. By thus removing the current barriers of time and distance, this strategy would dramatically enhance the potential for reconstruction and functional recovery in otherwise hopeless paralyzing injuries. Furthermore, this strategy may be used as a permanent axon replacement following destruction of lower motor neurons and would enable exogenous stimulation options, such as pacing of transplanted SMN axons in the phrenic nerve to avoid mechanical ventilation in high cervical cord injury or amyotrophic lateral sclerosis.

The innervation of the biceps brachii and brachialis muscles in specimens with a high incidence of an accessory biceps head.

We describe the patterns of motor branches to the elbow flexors in 106 fresh-frozen cadaveric upper extremities from 53 donors of the Latin American mestizo race. We identified a 20% incidence of an accessory biceps head. The innervation patterns to this accessory head were specifically described and added to the Yang classification as Type IV for the biceps and Type III for the brachialis. The patterns arising from the musculocutaneous nerve to the biceps brachii were of Type I in 69%, Type II in 9%, Type III in 7% and Type IV in 11%, and to the brachialis of Type I in 77%, Type II in 11% and Type III in 9%. In 4%, the branches did not originate from the musculocutaneous nerve. We hypothesize that the branch to the accessory biceps head might be considered as a donor for nerve transfer in selected brachial plexus injuries.

Surgical restoration of the upper limb in cervical spinal cord injury patients.

Prior to the 1950s, relatively few patients who suffered a transection of the cervical spinal cord survived their injury. Improved medical care and better coordination have resulted in greater numbers of patients surviving and leaving the hospital. The pioneering work of individual surgeons during the 1960s and 1970s stimulated interest in surgical restoration of upper limb function in tetraplegic patients. Since the publication of Moberg's monograph in 1978, surgical improvement of the upper limbs is regarded as one of the options that should be offered to tetraplegic individuals to improve their function. Patients are classified according to the level of spinal cord injury and the residual motor function (international classification: groups 1-9). Surgical procedures are adapted to the motor level for each group of patients. Indications for these procedures are well standardized, the techniques are well mastered, and predictable results can be expected. New nerve transfer techniques have been developed in recent years; they are currently being evaluated.

Nerve Transfers for Restoration of Elbow Flexion in Patients With Acute Flaccid Myelitis.

PURPOSE: The purpose of this study was to evaluate short- to midterm outcomes of patients with acute flaccid myelitis who underwent nerve transfers for restoration of elbow flexion. METHODS: Patients with a minimum of 10 months of follow up after undergoing nerve transfers to restore elbow flexion were clinically assessed using the Active Movement Scale (AMS). They were evaluated for any postoperative complications, particularly weakness in the distribution of the donor nerve(s). Fifteen of 25 consecutive patients who were treated using this surgical technique were included in the final analysis. RESULTS: All patients exhibited poor elbow flexion preoperatively (AMS 0 to 3). At a mean follow up of 17.3 months, 80% (15/25) of patients achieved excellent elbow flexion (AMS 6 or 7); 9 of these 15 had full active range of motion. Two patients achieved good elbow flexion (AMS 5) with antigravity movement to less than 50% of the passive range of motion. No cases of superficial or deep infection were reported, and all patients maintained identical motor function, relative to preoperative status, of the muscles innervated by the donor nerves. CONCLUSIONS: Nerve transfer surgery has shown promising short- to midterm results for recovery of nerve and muscle function, particularly for the restoration of elbow flexion. We recommend this treatment option for patients not demonstrating clinical improvement after 6 to 9 months of incomplete recovery. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Locating the anterior interosseous nerve in relation to the surgically relevant landmarks of the forearm: A cadaveric study.

BACKGROUND: This study emphasizes locating the anterior interosseous nerve (AIN) related to its level of origin, number, and lengths of its muscular branches and relation to surgically important landmarks such as the bi-epicondylar line, pronator teres, and Gantzer muscles. METHODS: The study was undertaken at a private Medical school in south India during 2019-20. The level of origin of AIN was measured from the bi-epicondylar line and its length was measured up to the upper border of the pronator quadratus using 44 cadaveric upper limbs. The number of branches given to flexor digitorum profundus (FDP) and flexor pollicis longus (FPL) was quantified and their lengths were measured. RESULTS: The nerve originated at a mean distance of 41.56 mm from the bi-epicondylar line. In 12 upper limbs, FDP received two branches and in two limbs, it received three branches. In 13 upper limbs, FPL received two branches from AIN. It was observed that the muscular branches for FDP were shorter than those for FPL. Gantzer muscle was observed in 18 (40%) specimens and was found superficial to the nerve. CONCLUSION: The muscular branches of AIN had a variable pattern of innervation. Multiple muscular branches to the FPL and FDP were observed in the upper 2/3rds of the forearm. These branches to FPL and FDP would aid as a source of nerve grafting and nerve transfer in the cases of upper extremity nerve palsies.