Elsevier

The Lancet

Volume 394, Issue 10198, 17–23 August 2019, Pages 565-575
The Lancet

Articles
Expanding traditional tendon-based techniques with nerve transfers for the restoration of upper limb function in tetraplegia: a prospective case series

https://doi.org/10.1016/S0140-6736(19)31143-2Get rights and content

Summary

Background

Loss of upper extremity function after cervical spinal cord injury greatly affects independence, including social, vocational, and community engagement. Nerve transfer surgery offers an exciting new option for the reanimation of upper limb function in tetraplegia. The aim of this study was to evaluate the outcomes of nerve transfer surgery used for the reanimation of upper limb function in tetraplegia.

Methods

In this prospective case series, we consecutively recruited people of any age with early (<18 months post-injury) cervical spinal cord injury of motor level C5 and below, who had been referred to a single centre for upper extremity reanimation and were deemed suitable for nerve transfer. All participants underwent single or multiple nerve transfers in one or both upper limbs, sometimes combined with tendon transfers, for restoration of elbow extension, grasp, pinch, and hand opening. Participants were assessed at 12 months and 24 months post-surgery. Primary outcome measures were the action research arm test (ARAT), grasp release test (GRT), and spinal cord independence measure (SCIM).

Findings

Between April 14, 2014, and Nov 22, 2018, we recruited 16 participants (27 limbs) with traumatic spinal cord injury, among whom 59 nerve transfers were done. In ten participants (12 limbs), nerve transfers were combined with tendon transfers. 24-month follow-up data were unavailable for three patients (five limbs). At 24 months, significant improvements from baseline in median ARAT total score (34·0 [IQR 24·0–38·3] at 24 months vs 16·5 [12·0–22·0] at baseline, p<0·0001) and GRT total score (125·2 [65·1–154·4] vs 35·0 [21·0–52·3], p<0·0001) were observed. Mean total SCIM score and mobility in the room and toilet SCIM score improved by more than the minimal detectable change and the minimal clinically important difference, and the mean self-care SCIM score improved by more than the minimal detectable change between baseline and 24 months. Median Medical Research Council strength grades were 3 (IQR 2–3) for triceps and 4 (IQR 4–4) for digital extensor muscles after 24 months. Mean grasp strength at 24 months was 3·2 kg (SD 1·5) in participants who underwent distal nerve transfers (n=5), 2·8 kg (3·2) in those who had proximal nerve transfers (n=9), and 3·9 kg (2·4) in those who had tendon transfers (n=8). There were six adverse events related to the surgery, none of which had any ongoing functional consequences.

Interpretation

Early nerve transfer surgery is a safe and effective addition to surgical techniques for upper limb reanimation in tetraplegia. Nerve transfers can lead to significant functional improvement and can be successfully combined with tendon transfers to maximise functional benefits.

Funding

Institute for Safety, Compensation, and Recovery Research (Australia).

Introduction

Cervical spinal cord injury is a devastating, life-changing injury, which can affect anyone at any time. Each year, 250 000–500 000 people worldwide acquire a spinal cord injury, with more than 50% of these injuries resulting in tetraplegia.1 Tetraplegia affects almost every aspect of a person's work, family, and social life. For people living with tetraplegia, improvement in hand function is the highest-ranked goal.2 Reconstruction of upper extremity function is a crucial component of the management of people with mid-level or low-level cervical spinal cord injury, as it has the capacity to restore important functions such as elbow extension, wrist extension, grasp, key pinch, and release. Traditionally, these functions have been reconstructed by use of tendon transfers, which move the tendon of a functioning muscle to a new insertion site to recreate the function of a paralysed muscle.3

The success of nerve transfers in the treatment of brachial plexus and peripheral nerve injury has inspired interest in nerve transfers for people with spinal cord injury.4 Nerve transfers are an attractive surgical option because they allow direct reanimation of the muscle anatomically and biomechanically designed to do that function. Nerve transfers can reanimate more than one muscle at a time—in contrast to tendon transfers, which usually require one tendon to reconstruct one function—and multiple nerve transfers can be completed simultaneously.5 Nerve transfers require a smaller operative incision and a substantially shorter immobilisation or splinting time post-surgery. In addition, nerve transfers avoid the technical challenges of tendon transfer surgery (intraoperative tendon tensioning) and mechanical failure post-surgery (tendon rupture, adhesion, or stretch). As nerve transfers can use different donors, the options for reconstruction and the total number of functions that can be restored is increased when combined with tendon transfers. In this study, we aimed to evaluate the clinical and functional outcomes of nerve transfer surgery used for reanimation of upper limb function in eligible patients with tetraplegia and to compare these with published outcomes for tendon transfer surgery.

Research in context

Evidence before this study

We reviewed the published literature for the primary outcome of nerve transfers for restoration of upper extremity function in tetraplegic patients. This search added to a review published by the first author in 2015. Using the key terms “tetraplegia”, “quadriplegia”, “nerve transfer”, and “spinal cord injury”, we searched MEDLINE, PubMed, Embase, and CINAHL databases from Feb 12, 2015, to Nov 31, 2018. We also manually checked the references of retrieved articles to identify additional studies. Nerve transfer surgery has been shown to be feasible, safe, and effective in numerous single case reports and small, retrospective case series. The case reports mainly focused on the description of new surgical procedures. The reporting quality of the case series was not high, lacking clarity in some areas such as the specific inclusion and exclusion criteria and the consecutive inclusion of patients. Although many reports included videotapes as supplementary material, only the Medical Research Council strength grading was used to measure outcomes, with no standardised functional outcome measures used. Rigorous prospective studies using standardised outcome measures in this population are scarce. A case series presenting outcomes for combinations of multiple nerve and tendon transfer surgeries has not previously been reported.

Added value of this study

This study reports on the largest prospective, consecutive case series of nerve transfers done at a single centre in the tetraplegic population to date, and examines the clinical and functional outcomes of nerve transfer surgery in detail. The use of qualitative outcome measures adds a subjective patient perspective. The unique combination of tendon and nerve transfers permits intraindividual comparison of tendon and nerve transfers for grasp and pinch and expands reconstructive options, while allowing patients to benefit functionally from the innate strengths of each technique.

Implications of all the available evidence

Nerve transfer surgery is a safe and reliable addition to the surgical options for upper extremity reconstruction in tetraplegia and leads to functional improvements similar to those of tendon transfer surgery. The assessment measures used and outcomes presented provide a baseline for comparison and are essential for international, collaborative research into this small population group with unique needs. Whether function and strength in muscles reanimated by nerve transfer continues to improve beyond 24 months remains to be shown. Consideration should be given to the inclusion of nerve transfer donors in the International Classification for Surgery of the Hand in Tetraplegia.

Section snippets

Study design and participants

We did a prospective case series with 2-year follow-up, reported in accordance with the PROCESS guidelines.6 We recruited people with early (<18 months post-injury) cervical spinal cord injury who had been consecutively referred to a single centre for upper extremity reanimation in Melbourne, Australia. Participants of any age were included if they had confirmed tetraplegia with a preoperative motor level of injury of C5 or below, were deemed suitable for nerve transfer surgery by the surgical

Results

Between April 14, 2014, and Nov 22, 2018, 16 participants (13 male and three female) with traumatic spinal cord injury were recruited (table 1). Motor vehicle accidents accounted for five (31%) injuries, with the remainder caused by falls, sports, or diving. The single neurological level of injury (SNLI), measured a mean 11 weeks post-spinal cord injury, ranged from C2 to C7, and all participants had motor complete injuries. All participants had recovered to a motor level of C5–C7 before

Discussion

This project is the first to comprehensively examine outcomes for early, multiple nerve transfer surgery in the upper limbs of people with tetraplegia following traumatic spinal cord injury, and is the largest prospective series of nerve transfers reported in this population to date. An additional unique aspect of this study is the combining of nerve transfers for grasp and pinch reconstruction in one hand with tendon transfers in the contralateral hand.

18 nerve transfers to the triceps for

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