The impact on post-operative shoulder function of intraoperative nerve monitoring of cranial nerve XI during modified radical neck dissection.

Intraoperative monitoring of the cranial nerve XI (CN XI) may decrease shoulder disability following modified radical neck dissection. Prospective study was designed comparing results of Constant Shoulder Score (CSS), Shoulder Pain and Disability Index (SPADI) and EMG score of the trapezius muscle (mT) before and after surgery. One side of the neck was monitored during surgery with intraoperative nerve monitor. EMG scores of the mT 6 months postoperatively were statistically better on monitored as compared to the non-monitored side of the neck (p = 0.041), while the differences of the CSS and SPADI were not statistically significant. Patients with better EMG scores of the mT at 6 weeks recuperated better and with smaller decrease of the CSS. Intraoperative monitoring is beneficial at the beginning of the surgeon's learning curve and in the process of familiarizing with anatomical variation of the CN XI.