Sonographic peripheral nerve cross‐sectional area in adults, excluding median and ulnar nerves: A systematic review and meta‐analysis

Abstract

Introduction/Aims Although electromyography remains the “gold standard” for assessing and diagnosing peripheral nerve disorders, ultrasound has emerged as a useful adjunct, providing valuable anatomic information. The objective of this study was to conduct a systematic review and meta‐analysis evaluating the normative sonographic values for adult peripheral nerve cross‐sectional area (CSA). Methods Medline and Cochrane Library databases were systematically searched for healthy adult peripheral nerve CSA, excluding the median and ulnar nerves. Data were meta‐analyzed, using a random‐effects model, to calculate the mean nerve CSA and its 95% confidence interval (CI) for each nerve at a specific anatomical location (= group). Results Thirty groups were identified and meta‐analyzed, which comprised 16 from the upper extremity and 15 from the lower extremity. The tibial nerve (n = 2916 nerves) was reported most commonly, followed by the common fibular nerve (n = 2580 nerves) and the radial nerve (n = 2326 nerves). Means and 95% confidence interval (CIs) of nerve CSA for the largest number of combined nerves were: radial nerve assessed at the spiral groove (n = 1810; mean, 5.14 mm2; 95% CI, 4.33 to 5.96); common fibular nerve assessed at the fibular head (n = 1460; mean, 10.18 mm2; 95% CI, 8.91 to 11.45); and common fibular nerve assessed at the popliteal fossa (n = 1120; mean, 12.90 mm2; 95% CI, 9.12 to 16.68). Publication bias was suspected, but its influence on the results was minimal. Discussion Two hundred thirty mean CSAs from 15 857 adult nerves are included in the meta‐analysis. These are further categorized into 30 groups, based on anatomical location, providing a comprehensive reference for the clinician and researcher investigating adult peripheral nerve anatomy.

The use and misuse of sonographic reference values in neuromuscular disease

“…In this issue of the journal, Eby and colleagues present a metaanalysis that collates 67 studies with published reference values of sonographic nerve sizes of various upper and lower extremity nerves. 17 The median and ulnar nerves were excluded from their study, as the authors indicate "the body of literature in this area is extensive and has been reported previously," including results of imaging in the longitudinal plane and data from pediatric populations. 18,19 The overview they provide shows a wide range of reported normal nerve sizes for the different nerves.…”