A Systematic Review of Contralateral C7 Transfer for the Treatment of Traumatic Brachial Plexus Injury

Abstract

Background Contralateral C7 (CC7) transfer has been used for treating traumatic brachial plexus injury. However, the effectiveness of CC7 transfer remains a subject of debate. We performed a systematic review to study the overall outcomes of CC7 transfer to different recipient nerves in traumatic brachial plexus injuries. Methods A literature search was conducted using PubMed and EMBASE databases to identify original articles related to CC7 transfer for traumatic brachial plexus injury. The data extracted were study/ patient characteristics, and objective outcomes of CC7 transfer to the recipient nerves. We normalized modifications of MRC and other outcome measures into an MRC-based outcome scale for comparisons. Results Thirty-nine studies were identified. The outcomes were categorized based on the three major recipient nerves: median, musculocutaneous, and radial/triceps nerves. Regarding overall functional recovery, 11% of patients achieved MRC grade M4 wrist flexion and 38% achieved M3. Grade M4 finger flexion was achieved by 7% of patients whereas 36% achieved M3. Finally, 56% of patients achieved ≥S3 sensory recovery in the median nerve territories. In the musculocutaneous nerve group, 38% of patients regained elbow flexor strength to M4 and 37% regained to M3. In the radial/triceps nerve group, 25% regained elbow or wrist extension strength to an MRC grade M4 and 25% regained to M3. Conclusions Outcome measures in the included studies were not consistently reported to uncover true patient-related benefits from the CC7 transfer. Reliable and validated outcome instruments should be applied to critically evaluate patients undergoing CC7 transfer.

Overexpression of Neuregulin-1 (NRG-1) Gene Contributes to Surgical Repair of Brachial Plexus Injury After Contralateral C7 Nerve Root Transfer in Rats

“…During a contralateral C7 nerve root transfer operation, the injured nerve on the injured side is repaired by transferring the partial or total seventh cervical nerve on the uninjured side using a nerve graft with more myelinated nerve fibers than in other available donor nerves, providing sufficient power for neurotization [ 7 ]. According to Yang et al, functional free-muscle repair and nerve transfer have been commonly treated with contralateral C7 nerve root transfer, especially in some Asian countries [ 8 ].…”

Contralateral C7 transfer to lower trunk via a subcutaneous tunnel across the anterior surface of the chest and neck for total brachial plexus root avulsion: a cadaveric study

“…Usually, when a normal cC7 root is transferred to the median nerve of the affected limb to restore wrist flexion, finger flexion, and hand sensation, a nerve graft of over 30 cm is needed to bridge the gap in adults [11]. Various reports showed that flexion restoration after transfer of the cC7 root to the median nerve was far from what could be expected [2, 11–13]. Why might this be?…”

“…It is thought that two major factors leading to poor restoration of hand function using the traditional C7 transfer method are the long distance between the cC7 root and the target muscle and an insufficient number of donor myelinated fibers to match the recipient nerves [2]. Hence, in attempts to achieve better recovery, the cC7 transfer has been modified to shorten the gap that needs to be bridged.…”

“…However, restoration of hand function using this traditional approach remains a technical and functional challenge. Using a long graft to bridge the gap between the donor C7 root and the recipient nerve is disadvantageous for encouraging early re-innervation of the recipient nerve [2]. Hence, shortening the length of the graft would be beneficial for functional recovery [3].…”

Passage through the carotid sheath: An alternative path to the pre-spinal route for direct repair of contralateral C7 to the lower trunk in total brachial plexus root avulsion injury

“…However, the feeble and inconsistent return of extrinsic flexion seen over the years has led to diminishing interest in the cC7 transfer. [ 1 2 3 4 5 6 7 ] The direct repair of cC7 with lower trunk produced superior and consistent result in restoration of extrinsic finger flexion. [ 8 9 ] However, despite the landmark report from Beijing in 2013, very few other units have adopted this technique.…”