Systematic Review With Meta-Analysis: Are Muscle Transfers a Satisfactory Treatment Option to Restore Shoulder Abduction in Delayed Adult Brachial Plexus Injuries?

Brachial plexus injuries usually result in significant upper limb disabilities and shoulder joint instability. Primary nerve reconstruction procedures are more effective if performed within six months from the injury. Secondary procedures, including muscle transfers, are usually indicated for delayed presentation (>6 months) or when the outcomes of primary procedures are unsatisfactory. A comprehensive systematic search of the MEDLINE, EMBASE, AMED, PubMed, and Cochrane databases was conducted in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Data, including demographic information, time to surgery, the extent of brachial plexus injury, surgical techniques, follow-up duration, and functional outcomes were collected and tabulated. Meta-analysis was conducted using Review Manager (RevMan) 5.4 software ([Computer program]. Version 5.3. Copenhagen: The Nordic Cochrane Centre, The Cochrane Collaboration, 2014). Seven studies were eligible to be included in this review, with a total of 218 patients. The average patient age was 28.39 ± 3 years, with a mean time to surgery of 29.87 ± 18 months. Forty-six (46) patients (21.10%) were treated as delayed presentation and 172 patients (78.89%) had muscle transfer performed as a secondary procedure. The mean time at follow-up was 18.86 ± 13.5 months. Upper trapezius muscle transfer was the most common transferred muscle (100%) either in isolation (n=159, 72.93%) or in combination with lower trapezius transfer (n=59, 27.06%). The mean preoperative and postoperative shoulder abduction were 12.22 ± 10.09 degrees and 58.36 ± 32.33 degrees, respectively (p < 0.05). Meta-analysis shows a statistically significant difference (CI at 95%, p<0.05) favoring postoperative shoulder abduction. Muscle transfers especially upper trapezius transfer could be a satisfactory secondary procedure to restore shoulder abduction and enhance shoulder joint stability.