Post-parotidectomy facial nerve function: comparison between original and modified Sunnybrook Facial Grading Systems

Area of Science:

• Otolaryngology
• Neurosurgery
• Plastic Surgery

Background:

• Facial nerve dysfunction is a primary complication following parotidectomy.
• Accurate assessment of facial nerve function is crucial for patient outcomes.

Purpose of the Study:

• To evaluate the modified Sunnybrook Facial Grading System (mS-FGS) against the original S-FGS.
• To determine if mS-FGS enhances facial nerve function assessment post-parotidectomy.

Main Methods:

• Prospective, longitudinal study of 101 patients undergoing parotidectomy (2016-2020).
• Facial nerve function assessed using original and modified S-FGS at 1-day and 20-30 day post-surgery.
• Analysis of intra- and inter-rater agreement for new facial expression assessments.

Main Results:

• mS-FGS yielded significantly lower scores, indicating greater sensitivity (p < 0.001).
• The mandibular marginal branch was most frequently injured (68.3% on day 1, 52.5% at outpatient evaluation).
• High intra- and inter-rater reliability was observed for the mS-FGS.

Conclusions:

• The modified Sunnybrook System, incorporating mandibular branch evaluation, improves accuracy in assessing post-parotidectomy facial nerve dysfunction.
• This enhanced system provides a more precise measure of nerve impairment.