Quantifying the Learning Curve in Trigeminal Nerve Assessment Using Medical Research Council Scale: A Repeated-Measures Study Among Oral and Maxillofacial Surgery Residents and Faculty Experts.

BACKGROUND

Trigeminal nerve injury (TNI) complicates oral and maxillofacial surgery (OMS) and dental procedures; accurate neurosensory testing (NST) using the Medical Research Council Scale (MRCS) guides diagnosis and referral. It is unclear if a standardized neurosensory training program for residents can improve the accuracy of diagnosing trigeminal nerve injuries.

PURPOSE: To measure the effect of standardized training on trigeminal NST accuracy among OMS residents.

STUDY DESIGN, SETTING, SAMPLE: A prospective cohort study at the University of Illinois Chicago. OMS residents completed NST on adult subjects with stable unilateral TNI before and after training.

PRIMARY PREDICTOR VARIABLE: NST training status (pre vs post). The 15-minute training comprised a didactic on trigeminal anatomy and MRCS, a demonstration video, and supervised practice. Two faculty examiners served as the reference standard.

MAIN OUTCOME VARIABLE: Mean absolute error (MAE) of resident MRCS scores relative to the faculty median; smaller MAE indicates greater accuracy.

COVARIATES: Sex and postgraduate year (PGY) of training.

SECONDARY OUTCOMES: Examination duration, self-reported confidence (5-point Likert), and inter-rater reliability (intraclass correlation coefficient).

ANALYSES: Paired t-tests compared pre/post values. Mann-Whitney U (sex) and Spearman correlation (PGY) assessed covariate associations; a mixed-effects model adjusted for both. Statistical significance was set at α = 0.05.

RESULTS

Nine OMS residents (6 male [67%], 3 female [33%]; 6 PGY-1, 1 PGY-3, 2 PGY-4) and 4 subjects participated. MAE decreased from 0.4 (SD 0.3) to 0.1 (SD 0.1) (P = .01); intraclass correlation coefficient improved from 0.20 to 0.65. Neither sex (P = .7) nor PGY (P = .8) was associated with MAE; the training effect remained statistically significant after adjustment (β = -0.31, P = .001). Confidence increased from 3.0 (SD 1.3) to 4.0 (SD 0.6) (P = .02); duration shortened from 202 (SD 70) to 133 (SD 48) seconds (P = .006).

CONCLUSIONS AND RELEVANCE: A 15-minute standardized training programme reduced resident MRCS scoring error and improved inter-rater reliability from poor to moderate. OMS residency programmes should incorporate brief structured NST training to improve TNI assessment.