Novel Nerve Transfers for Motor and Sensory Restoration in High Cervical Spinal Cord Injury

Peripheral nerve transfers for dysfunctions in central nervous system injuries: a systematic review

BACKGROUND

The review highlights recent advancements and innovative uses of nerve transfer surgery in treating dysfunctions caused by central nervous system (CNS) injuries, with a particular focus on spinal cord injury (SCI), stroke, traumatic brain injury, and cerebral palsy.

METHODS

A comprehensive literature search was conducted regarding nerve transfer for restoring sensorimotor functions and bladder control following injuries of spinal cord and brain, across PubMed and Web of Science from January 1920 to May 2023. Two independent reviewers undertook article selection, data extraction, and risk of bias assessment with several appraisal tools, including the Cochrane Risk of Bias Tool, the JBI Critical Appraisal Checklist, and SYRCLE's ROB tool. The study protocol has been registered and reported following PRISMA and AMSTAR guidelines.

RESULTS

Nine hundred six articles were retrieved, of which 35 studies were included (20 on SCI and 15 on brain injury), with 371 participants included in the surgery group and 192 in the control group. These articles were mostly low-risk, with methodological concerns in study types, highlighting the complexity and diversity. For SCI, the strength of target muscle increased by 3.13 of Medical Research Council grade, and the residual urine volume reduced by more than 100 ml in 15 of 20 patients. For unilateral brain injury, the Fugl-Myer motor assessment (FMA) improved 15.14-26 score in upper extremity compared to 2.35-26 in the control group. The overall reduction in Modified Ashworth score was 0.76-2 compared to 0-1 in the control group. Range of motion (ROM) increased 18.4-80° in elbow, 20.4-110° in wrist and 18.8-130° in forearm, while ROM changed -4.03°-20° in elbow, -2.08°-10° in wrist, -2.26°-20° in forearm in the control group. The improvement of FMA in lower extremity was 9 score compared to the presurgery.

CONCLUSION

Nerve transfer generally improves sensorimotor functions in paralyzed limbs and bladder control following CNS injury. The technique effectively creates a 'bypass' for signals and facilitates functional recovery by leveraging neural plasticity. It suggested a future of surgery, neurorehabilitation and robotic-assistants converge to improve outcomes for CNS.

Upper Limb Nerve Transfer Surgery in Patients With Tetraplegia

IMPORTANCE

Cervical spinal cord injury (SCI) causes devastating loss of upper extremity function and independence. Nerve transfers are a promising approach to reanimate upper limbs; however, there remains a paucity of high-quality evidence supporting a clinical benefit for patients with tetraplegia.

OBJECTIVE

To evaluate the clinical utility of nerve transfers for reanimation of upper limb function in tetraplegia.

DESIGN, SETTING, AND PARTICIPANTS

In this prospective case series, adults with cervical SCI and upper extremity paralysis whose recovery plateaued were enrolled between September 1, 2015, and January 31, 2019. Data analysis was performed from August 2021 to February 2022.

INTERVENTIONS

Nerve transfers to reanimate upper extremity motor function with target reinnervation of elbow extension and hand grasp, pinch, and/or release.

MAIN OUTCOMES AND MEASURES

The primary outcome was motor strength measured by Medical Research Council (MRC) grades 0 to 5. Secondary outcomes included Sollerman Hand Function Test (SHFT); Michigan Hand Outcome Questionnaire (MHQ); Disabilities of Arm, Shoulder, and Hand (DASH); and 36-Item Short Form Health Survey (SF-36) physical component summary (PCS) and mental component summary (MCS) scores. Outcomes were assessed up to 48 months postoperatively.

RESULTS

Twenty-two patients with tetraplegia (median age, 36 years [range, 18-76 years]; 21 male [95%]) underwent 60 nerve transfers on 35 upper limbs at a median time of 21 months (range, 6-142 months) after SCI. At final follow-up, upper limb motor strength improved significantly: median MRC grades were 3 (IQR, 2.5-4; P = .01) for triceps, with 70% of upper limbs gaining an MRC grade of 3 or higher for elbow extension; 4 (IQR, 2-4; P < .001) for finger extensors, with 79% of hands gaining an MRC grade of 3 or higher for finger extension; and 2 (IQR, 1-3; P < .001) for finger flexors, with 52% of hands gaining an MRC grade of 3 or higher for finger flexion. The secondary outcomes of SHFT, MHQ, DASH, and SF36-PCS scores improved beyond the established minimal clinically important difference. Both early (<12 months) and delayed (≥12 months) nerve transfers after SCI achieved comparable motor outcomes. Continual improvement in motor strength was observed in the finger flexors and extensors across the entire duration of follow-up.

CONCLUSIONS AND RELEVANCE

In this prospective case series, nerve transfer surgery was associated with improvement of upper limb motor strength and functional independence in patients with tetraplegia. Nerve transfer is a promising intervention feasible in both subacute and chronic SCI.

Importance of brain alterations in spinal cord injury

Spinal cord injury (SCI) destroys the sensorimotor pathway and blocks the information flow between the peripheral nerve and the brain, resulting in autonomic function loss. Numerous studies have explored the effects of obstructed information flow on brain structure and function and proved the extensive plasticity of the brain after SCI. Great progress has also been achieved in therapeutic strategies for SCI to restore the "re-innervation" of the cerebral cortex to the limbs to some extent. Although no thorough research has been conducted, the changes of brain structure and function caused by "re-domination" have been reported. This article is a review of the recent research progress on local structure, functional changes, and circuit reorganization of the cerebral cortex after SCI. Alterations of structure and electrical activity characteristics of brain neurons, features of brain functional reorganization, and regulation of brain functions by reconfigured information flow were also explored. The integration of brain function is the basis for the human body to exercise complex/fine movements and is intricately and widely regulated by information flow. Hence, its changes after SCI and treatments should be considered.

Nerve transfers in tetraplegia: a review and practical guide

INTRODUCTION

Spinal cord injury (SCI) may lead to tetraplegia. Several nerve transfers have been successfully used for the restoration of the upper limb in tetraplegia. Reconstruction of an upper limb is individualized based on the functional level. In this study, the authors reviewed nerve transfers based on the injury level for the restoration of upper limb function in tetraplegia.

EVIDENCE ACQUISITION

We performed this study to review nerve transfers in tetraplegia by searching MEDLINE and EMBASE databases to identify relevant articles published through December 2020. We selected studies that reported cases in tetraplegia and extracted information on demographic data, clinical characteristics, operative details, and strength outcomes based on each injury level after surgery.

EVIDENCE SYNTHESIS

Total of 29 journal articles reporting on 275 nerve transfers in 172 upper limbs of 121 patients were included in the review. The mean time between SCI and nerve transfer surgery was 21.37 months (range: 4-156 months), and the follow-up time was 21.34 months (range: 3-38 months). The best outcomes were achieved for the restoration of wrist/finger extension and elbow extension.

CONCLUSIONS

Nerve transfer can provide a new function in tetraplegic patients' upper limbs to improve daily living activities. The type of surgical procedure should be performed based on the functional level of SCI and the individual's needs. Functional recovery occurs more in extensor muscles than flexors. Nerve transfer is a promising option in the reconstruction of upper limb function in tetraplegia.

An Often Easily Missed Injury in the Presence of Orthopaedic Trauma: A Case Series of Derived Injury

Derived disaster is a common concept in emergencies such as earthquakes. With the progress of society, the incidence of fractures caused by high-energy trauma has increased year by year. After the first injury, the possibility of derived injury caused by the original injury also increases rapidly. Orthopaedic surgeons, especially trauma orthopaedic surgeons, lack sufficient understanding and recognition of this kind of injury. The purpose of this article is to present a case series of an often missed injury pattern that is associated with an original injury. The diagnosis of derived injury may go unrecognized in a considerable number of cases and delayed treatment decreases the success rate of soft tissue repairing; therefore, a high index of suspicion and a proper early diagnosis is of paramount importance. We also describe the current surgical management used by the authors, and propose the concept of "derived injury", studying its clinical significance in traumatic orthopaedics.

The 2019 yearbook of Neurorestoratology

Time is infinite movement in constant motion. We are glad to see that Neurorestoratology, a new discipline, has grown into a rich field involving many global researchers in recent years. In this 2019 yearbook of Neurorestoratology, we introduce the most recent advances and achievements in this field, including findings on the pathogenesis of neurological diseases, neurorestorative mechanisms, and clinical therapeutic achievements globally. Many patients have benefited from treatments involving cell therapies, neurostimulation/neuromodulation, brain–computer interface, neurorestorative surgery or pharmacy, and many others. Clinical physicians can refer to this yearbook with the latest knowledge and apply it to clinical practice.