Cross‐sectional area reference values for peripheral nerve ultrasound in adults: A systematic review and meta‐analysis—Part III: Cervical nerve roots and vagal nerve

Abstract

Background and purpose Measurement of the cross‐sectional area (CSA) of cervical nerve roots using ultrasound is useful in the evaluation of inflammatory polyneuropathies, and measurement of CSA of the vagal nerve might give information about involvement of the autonomic nervous system. We performed a systematic review and meta‐analysis of published CSA reference values for cervical nerve roots and vagal nerve. Methods We included available‐to‐date nerve ultrasound studies on healthy adults and provide meta‐analysis for CSA of the following nerves: cervical nerve roots C5, C6, and C7 as well as vagal nerve in the carotid sheath at the carotid bifurcation level. We report regression and correlation analyses for age, gender, height, weight, and geographic continent. Results We included 11 studies with 885 healthy volunteers (mean age = 42.7 years) and 3149 examined nerve sites. Calculated mean pooled CSA of C5 root was 5.6 mm2 (95% confidence interval [CI] = 4.6–6.7 mm2, n = 911), of C6 root was 8.8 mm2 (95% CI = 7.4–10.3 mm2, n = 909), of C7 root was 9.5 mm2 (95% CI = 8.0–10.9 mm2, n = 909), and of vagal nerve was 2.2 mm2 (95% CI = 1.5–2.9 mm2, n = 420). No heterogeneity was found across studies for any site. Subgroup analysis revealed no significant effects of age, gender, height, weight, and geographic continent on CSA for any of these nerve sites. Conclusions We provide the first meta‐analysis on CSA reference values for the cervical nerve roots and the vagal nerve, with no heterogeneity of reported CSA values at all nerve sites. Our data facilitate the goal of an international standardized evaluation protocol.

Nerve ultrasound findings in Sjögren's syndrome‐associated neuropathy

“…However, this fraction might even be underestimated as high cutoff values for enlarged CSAs in comparison to other studies were applied. 23 Nevertheless, comparable studies on patients with CIDP found pathologic ultrasound findings with similar frequencies (64-89%). [24][25][26] In our study, abnormalities on nerve ultrasound were observed in four out of seven patients with Sjögren's syndrome and clinical signs of neuropathy but without neurophysiologic evidence of neuropathy.…”

“…In our analysis, 72% of patients with Sjögren’ syndrome and suspected neuropathy showed abnormal findings on nerve ultrasound. However, this fraction might even be underestimated as high cutoff values for enlarged CSAs in comparison to other studies were applied 23 . Nevertheless, comparable studies on patients with CIDP found pathologic ultrasound findings with similar frequencies (64–89%) 24–26 .…”

Vagus nerve ultrasound in transthyretin familial amyloid polyneuropathy: A pilot study

“… 13 , 14 , 24 However, the VN CSAs in HCs did not vary significantly between age, gender, height, weight, and races in adults according to a systematic review and meta‐analysis. 25 …”

Nerve Ultrasound Distinguishes Non-Inflammatory Axonal Polyneuropathy From Inflammatory Polyneuropathy With Secondary Axonal Damage

“…Both aspects might influence the sonographic pattern of peripheral nerve enlargement, which makes our results valuable as they represent daily clinical life (12,17,23,24). We did not analyze data of height, body weight, and age, as the effects of these demographic data on CSA are still under discussion (25)(26)(27)(28).…”