Facial Nerve Monitoring during Parotidectomy: A Systematic Review and Meta‐analysis

Abstract

Objectives: Determine the effectiveness of intraoperative facial nerve monitoring (FNM) in preventing immediate and permanent postoperative facial nerve weakness in patients undergoing primary parotidectomy. Methods: Systematic review and meta-analysis. A comprehensive literature search was conducted using the PubMed-NCBI database from 1970 to 2014. Acceptable studies included controlled series that evaluated facial nerve function following primary parotidectomy with or without FNM (intraoperative nerve monitor vs. control). Primary and secondary endpoints were defined as immediate postoperative and permanent facial nerve weakness (≥2 House-Brackmann score), respectively. Results: A total of 1414 articles were reviewed, resulting in 8 articles that met inclusion criteria. In total, 626 patients were included in the final meta-analysis. The incidence of immediate postoperative weakness following parotidectomy was significantly lower in the FNM group compared with the unmonitored group (22.4% vs 35.0%, P = .001). The incidence of permanent weakness was also lower, but this difference was not statistically significant (4.2% vs 7.6%, P = .10). The number of monitored cases needed to prevent 1 incidence of immediate postoperative facial nerve weakness was 8 given an absolute risk reduction of 12.6%. This corresponded to a 49% decrease in the incidence of immediate facial nerve dysfunction (odds ratio, 0.51; 95% confidence interval, 0.34 to 0.76, P = .001). Conclusions: In primary cases of parotidectomy, intraoperative facial nerve monitoring decreases the risk of immediate postoperative facial nerve weakness, but does not appear to influence the final outcome of permanent facial nerve weakness.

Facial nerve paralysis postparotidectomy: A retrospective review of the prevalence and risk factors at a tertiary center

“…Sood et al showed that EMG decreased the risk of facial nerve injury during surgery, whereas Grosheva et al found that EMG did not decrease the incidence of facial nerve injury. [13,15] In the present study, EMG monitoring was not associated with the rate of temporary or permanent facial nerve injury.…”

“…[7] Several factors have been associated with facial nerve injury including a history of malignant pathology, deep lobe involvement, lack of nerve monitoring, use of diathermy, surgical techniques, revision surgery, additional neck dissection, and diabetes. [8][9][10][11][12][13][14] In the present study, we aimed to determine the prevalence of postparotidectomy facial nerve paralysis and to identify risk factors associated with its development.…”

Association Between Facial Nerve Monitoring With Postoperative Facial Paralysis in Parotidectomy

“…Clinical assumptions that are validated in the studies include the fact that more extensive facial nerve dissection (as in PP vs TP and in revision surgery) leads to higher rates of transient facial nerve dysfunction but not necessarily permanent dysfunction. [22][23][24][25] Benign and malignant disease, when preoperative facial nerve function is normal and branches are not sacrificed for tumor control, have similar outcomes in facial nerve function. Benign inflammatory disease has a worse outcome owing to fibrosis of glandular tissue.…”

Posterior auricular artery as a novel anatomic landmark for identification of the facial nerve: A cadaveric study

“…Facial nerve (CNVII, the seventh paired cranial nerve) injury during parotid surgery is a feared complication and can result in facial paralysis with serious implications on patient quality of life. Unfortunately, despite preservation techniques, the transient CNVII dysfunction rate and permanent facial nerve weakness rates are reported up to 65% and 4%‐7%, respectively, after parotidectomy . Even for patients with benign parotid tumors undergoing surgery, the frequency of temporary and permanent facial nerve dysfunction is reported to be as high as 26.3% and 1.7%, respectively .…”