Median and ulnar nerve anastomoses in the upper limb: A meta‐analysis

INTRODUCTION: The most frequently described anomalous neural connections between the median and ulnar nerves in the upper limb are: Martin-Gruber anastomosis (MGA), Marinacci anastomosis (MA), Riche-Cannieu anastomosis (RCA), and Berrettini anastomosis (BA). The reported prevalence rates and characteristics of these anastomoses vary significantly between studies. METHODS: A search of electronic databases was performed to identify all eligible articles. Anatomical data regarding the anastomoses were pooled into a meta-analysis using MetaXL 2.0. RESULTS: A total of 58 (n = 10,562 upper limbs) articles were included in the meta-analysis. The pooled prevalences were: MGA, 19.5% (95% confidence interval CI, 16.2%-23.1%); MA, 0.7% (95% CI, 0.1%-1.7%); RCA, 55.5% (95% CI, 30.6%-79.1%); and BA, 60.9% (95% CI, 36.9%-82.6%). The results also showed that MGA was more commonly found unilaterally (66.8%), on the right side (15.7%), following an oblique course (84.8%), and originating from the anterior interosseous nerve with a prevalence of 57.6%. CONCLUSIONS: As anastomoses between the median and ulnar nerves occur commonly, detailed anatomical knowledge is essential for accurate interpretation of electrophysiological findings and reducing the risk of iatrogenic injuries during surgical procedures. Muscle Nerve 54: 36-47, 2016.