GlideScope® versus Macintosh laryngoscope for assessment of post-thyroidectomy vocal cord dysfunction: prospective randomized study.

BACKGROUND

Early detection of post-thyroidectomy vocal cord dysfunction is crucial. This study compared GlideScope® with Macintosh direct laryngoscope (MDL) regarding the accuracy of assessment of post-thyroidectomy vocal cord dysfunction.

METHODS

One hundred and twenty patients scheduled for elective thyroidectomy, aged 18 - 50 years, of either sex were enrolled in the study. Standard general anesthesia technique was used in all patients. At the end of operation, patients were randomly allocated into one of the following sequences: 1) examined with MDL then GlideScope®, or 2) examined with GlideScope® then MDL. Postoperative tele-laryngoscopic examination was done after 12 hours. The primary outcome of the study was the sensitivity and the specificity of GlideScope® to detect vocal cord dysfunction while the secondary outcomes were the Cormack-Lehane grade of the glottis visualization and the incidence of complications.

RESULTS

The incidence of vocal cord dysfunction was 15 (12.5%); all cases were unilateral. The GlideScope® was more sensitive (86.7%) and specific (95.2%) with higher diagnostic accuracy (94.2%) for detecting vocal cord dysfunction than MDL. There was a high agreement between the GlideScope® findings and the final diagnosis (kappa 0.754 [95% CI: 0.581-0.928]). Cormack-Lehane score was significantly better by the GlideScope® than by the MDL (P<0.001). The incidence of hoarseness of voice was 32 (26.7%) with eight cases among the diagnosed patients. No cases of aspiration or stridor were recorded.

CONCLUSIONS

This study demonstrates that GlideScope® is a better alternative to MDL for an accurate detection of post-thyroidectomy vocal cord dysfunction.