Using the Craniovertebral Angle to Quantify Intraoperative Ergonomic Risk

Abstract

Objective

To measure the craniovertebral angle during tonsillectomy, assess the interrater reliability of our methodology, and investigate the correlations of the Rapid Upper Limb Assessment and the craniovertebral angle to quantify ergonomic risk.

Study Design

Prospective, observational study.

Setting

Tertiary care pediatric institution.

Methods

Neck posture was evaluated for 92 images with 7 surgeons. Lateral images of the surgeon were captured every minute in a standardized method. Images were assessed by 3 raters, measuring the craniovertebral angle, defined as the angle between a horizontal line through the C7 vertebrae and another line through C7 and the tragus of the ear. Interrater reliability of the craniovertebral angle was evaluated using the κ statistic. Per prior publications, reports of neck pain were frequent when the craniovertebral angle value was <50°; thus, we defined an abnormal posture if the craniovertebral angle was <50°.

Results

Mean (SD) craniovertebral angle during tonsillectomy was 26.0° (11.3°). One hundred percent of procedures had at least 1 assessment of abnormal posture. The lowest interrater reliability was 0.77 (CI: 0.67-0.87). Rapid Upper Limb Assessment and craniovertebral angle (CA) correlation was −0.12 (P = .27) and, therefore, null.

Conclusion

Poor posture during tonsillectomy places otolaryngologists at intraoperative ergonomic risk. The craniovertebral angle is a predictor of future neck pain, and a pathologic neck position during tonsillectomy was identified. Given the high interrater reliability, our approach to assessing intraoperative surgical ergonomics was validated. Overall, RULA and the CA are not a substitute for one another but complementary.