Use Of Facial Nerve Monitoring Research Articles

Proposals for Standardization of Intraoperative Facial Nerve Monitoring during Parotid Surgery.

Intraoperative facial nerve monitoring (FNM) has been widely accepted as an adjunct during parotid surgery to facilitate identification of the facial nerve (FN) main trunk, dissection of FN branches, confirmation of FN function integrity, detection of FN injury and prognostication of facial expression after tumor resection. Although the use of FNM in parotidectomy is increasing, little uniformity exists in its application from the literature. Thus, not only are the results of many studies difficult to compare but the value of FNM technology is also limited. The article reviews the current literature and proposes our standardized FNM procedures during parotid surgery, such as standards in FNM setup, standards in general anesthesia, standards in FNM procedures and application of stimulus currents, interpretation of electrophysiologic signals and prediction of the facial expression outcome and pre-/post-operative assessment of facial expressions. We hope that the FNM standardized procedures will provide greater uniformity, improve the quality of applications and contribute to future research.

Prospective Assessment of Intraoperative Facial Nerve Monitoring in Patients Undergoing Partial Parotidectomy.

The most significant complication of parotid gland tumor surgery is facial weakness. This study compares the occurrence of transient facial palsy in patients with parotid gland tumors who underwent surgery without monitoring to those who underwent surgery with monitoring. The study's aim was to investigate facial nerve function in patients undergoing parotidectomy as well as the effect of intraoperative facial nerve monitoring and the effect of certain risk factors on the surgery and onset of postoperative facial palsy. This prospective study included 100 patients who underwent parotidectomy. The study cohort was divided into two groups. Group I included 50 patients who underwent surgery without neuromonitoring and group II included 50 patients who underwent surgery with neuromonitoring. The neurological assessment was conducted using the House–Brackmann scale. Preoperatively and one month postoperatively, electroneuronography (ENoG) and blink reflex tests were done. The analyses showed a significant reduction of the compound muscle action potential (CMAP) amplitude of the orbicularis oculi and orbicularis oris muscles and prolonged R1 and R2 blink reflex latencies 1 month after surgery. On neurological and electrophysiological studies, the rate of postoperative transient facial nerve dysfunction was significantly different between the groups. Significantly more patients, operated with use of facial nerve monitoring, presented postoperatively normal nerve function (i.e., House–Brackmann grade I) compared to those who underwent surgery without monitoring (78% and 26%, respectively; p < 0.001). Monitoring had a statistically significant impact on the prevalence of facial nerve conduction disorders in patients who underwent surgery, according to the blink reflex and ENoG studies. The duration of the surgical procedure was not affected by monitoring in any way. The clinical evaluation of facial nerve function (House–Brackmann scale) and some ENoG results 1 month after surgery were found to have a significant correlation. To summarize, using monitoring considerably reduced the negative impact of local factors and the prevalence of transient facial nerve palsy.

Outcome of Postoperative Facial Nerve Function Following Electromyographic Facial Nerve Monitoring During Parotidectomy for Benign Lesions: a Retrospective Study.

Does use of Facial nerve monitors during parotidectomy decrease incidence of facial paralysis/paresis without useof facial paresis?This study was done to compare the incidence, grade and risk factors of facial palsy in patients undergoing parotidectomy for benign parotid lesions with and without use of facial nerve monitor. This is a retrospective study. Eighty parotid patients operated for benign parotid lesions from 2013 to 2020 were retrospectively analysed. Demography details, history of the patients, history of addictions, clinical examination findings, investigation findings like the biopsy report, FNAC report, imaging i.e., CT / MRI / USG, use of intraoperative facial nerve monitor, time taken to identify the facial nerve, postoperative facial nerve palsy, facial nerve stimulation test and recovery time were analysed. Fifty patients were operated without use of facial nerve monitor, and 30 patients were operated using facial nerve monitor. Postoperative facial nerve complications were seen in 28 out of 80 patients (35%). Postoperative facial nerve complications were observed in 5 out of 30 patients (20%) in whom facial nerve monitoring was used. Marginal mandibular nerve palsy was observed in 4 patients and 1 patient had weakness of both marginal mandibular and orbital branches. While in postoperative facial nerve complications were observed in 25 out of 50 patients (50%), marginal mandibular nerve palsy was observed in 15 patients (40%), grade 3 facial palsy was observed in 3 out of 50 patients (6%), and grade 4 facial palsy were observed in 2 out of 50 patients (4%). The use of intraoperative FNM significantly lowered the incidence of paralysis.

Preoperative Criteria Predict Operative Time Variability Within Tympanoplasty Procedures.

To identify preoperative patient and surgical parameters that predict operative time variability within tympanoplasty current procedural terminology (CPT) codes. Retrospective. Tertiary referral center. One hundred twenty eight patients who underwent tympanoplasty (CPT code 69631) or tympanoplasty with ossicular chain reconstruction (69633) by a single surgeon over 3 years. Procedures were preoperatively assigned a complexity modifier: Level 1 (small or posterior perforation able to be repaired via transcanal approach), Level 2 (large perforation or other factor requiring postauricular approach), or Level 3 (cholesteatoma or severe infection). Total in-room time (nonoperative time plus actual operative time). Consideration of preoperative parameters including surgical complexity, surgical facility, use of facial nerve monitoring, laser usage, resident involvement, revision surgery, and underlying patient characteristics (American Society of Anesthesiologists [ASA] score, body mass index [BMI]) accounted for up to 69% of surgical time variance. Across both CPT codes, surgical complexity levels accurately stratified operative times (p < 0.05). Total time was longer (by 30.0 min for 69631, 55.4 min for 69633) in Level 3 procedures compared with Level 2, while Level 1 cases were shorter (27.6, 33.9 min). Resident involvement added 25 and 32 minutes to total time (p < 0.02). Nonoperative preparation times were longer (22.1, 15.4 min) in the main hospital compared with ambulatory surgical center (p < 0.001). There is significant surgical time variability within tympanoplasty CPT codes, which can be accurately predicted by the preoperative assignment of complexity level modifiers and consideration of patient and surgical factors. Application of complexity modifiers can enable more efficient surgical scheduling.

Value of the Use of Facial Nerve Monitoring in Otorhinolaryngological Surgeries

Abstract Background The anatomy of the facial nerve is among the most complex of the cranial nerves. Facial nerve is not just a pure voluntary motor nerve but comprises parasympathetic, general sensory, and special sensory components as well. Facial nerve monitoring is one of the most exciting innovations in neurotologic surgery in the past decade. Objective To determine the effect of intraoperative facial nerve monitoring on postoperative facial nerve function and on operative time. Patients and Methods In general terms, FNM means electrophysiological monitoring. This technique provides for monitoring of facial muscle activity via electromyography (EMG).The EMG is typically recorded with needle electrodes placed in facial nerve muscles. Voluntary activation of the facial nerve in the alert patient as well as intraoperative electrical stimulation or mechanical irritation during surgery generates motor evoked potentials. In this meta-analysis, the included studies are ten in number with total 593 patient (control= 311, IOFNM = 282) Results Comparison of facial nerve monitoring vs. no monitoring as regards incidence of facial nerve dysfunction shows there is no evidence of heterogeneity and statistically significant (p-value &amp;lt;0.01) which indicate that the incidence of FN dysfunction in the monitoring group is lower than the dysfunction in the no monitoring group. Comparison of facial nerve motoring vs. no monitoring as regards operative time shows there is no evidence of heterogeneity. Under the random effect model, the standardized mean difference (SMD) is -0.62 which is statistically significant (p-value &amp;lt;0.01) favoring facial nerve motoring over no monitoring. Which indicate that the mean surgery time was lower in the group of patients operated with facial monitoring as compared with the unmonitored group. Conclusion So, our meta-analysis shows statistically significant results which favor facial nerve monitoring over no monitoring as regards decreasing the operative time and improving of postoperative facial nerve dysfunction.

Assessment of Intraoperative Nerve Monitoring Parameters Associated With Facial Nerve Outcome in Parotidectomy for Benign Disease

Prior studies suggest that the use of facial nerve monitoring decreases the rate of immediate postoperative facial nerve weakness in parotid surgery, but published data are lacking on normative values for these parameters or cutoff values to prognosticate facial nerve outcomes. To identify intraoperative facial nerve monitoring parameters associated with postoperative weakness and to evaluate cutoff values for these parameters under which normal nerve function is more likely. This retrospective case series of 222 adult patients undergoing parotid surgery for benign disease performed with intraoperative nerve monitoring was conducted at an academic medical institution from September 13, 2004, to October 30, 2014. The data analysis was conducted from May 2018 to January 2019. The main outcome measure was facial nerve weakness. Receiver operating characteristic curves were generated to define optimal cut point to maximize the sensitivity and specificity of the stimulation threshold, mechanical events, and spasm events associated with facial nerve weakness. Of 222 participants, 121 were women and 101 were men, with a mean (SD) age of 51 (16) years. The rate of temporary facial nerve paresis of any nerve branch was 45%, and the rate of permanent paralysis was 1.3%. The mean predissection threshold was 0.22 milliamperes (mA) (range, 0.1-0.6 mA) and the mean postdissection threshold was 0.24 mA (range, 0.08-1.0 mA). The average number of mechanical events was 9 (range, 0-66), and mean number of spontaneous spasm events was 1 (range, 0-12). Both the postdissection threshold (area under the curve [AUC], 0.69; 95% CI, 0.62-0.77) and the number of mechanical events (AUC, 0.58; 95% CI, 0.50-0.66) were associated with early postoperative facial nerve outcome. The number of spasm events was not associated with facial nerve outcome. The optimal cutoff value for the threshold was 0.25 mA, and the optimal cutoff for number of mechanical events was 8. If a threshold of greater than 0.25 mA was paired with more than 8 mechanical events, there was a 77% chance of postoperative nerve weakness. Conversely, if a threshold was 0.25 mA or less and there were 8 mechanical events or less, there was 69% chance of normal postoperative nerve function. No parameters were associated with permanent facial nerve injury. Postdissection threshold and the number of mechanical events are associated with immediate postoperative facial nerve function. Accurate prediction of facial nerve function may provide anticipatory guidance to patients and may provide surgeons with intraoperative feedback allowing adjustment in operative techniques and perioperative management.

Nerve Integrity Monitor（NIM）が有用であった副耳下腺多形腺腫例

Because accessory parotid gland tumors are relatively rare, no standard management method has been established yet. In this paper, we describe the surgical approach and usefulness of facial nerve monitoring in a patient with pleomorphic adenoma of the accessory parotid gland. The patient, a 61-year-old female, presented with a painless, hard mass on the left cheek. We performed surgical resection of the tumor by the peri-auricular-cervical flap approach. The buccal branch of the facial nerve was easily detected on the tumor by nerve integrity monitoring (NIM). No postoperative facial nerve palsy was observed. Histopathology of the resected tomor, which measured 23×17×18 mm in size, revealed that it was a pleomorphic adenoma. NIM was useful in the for safe resection of the accessory parotid gland tumor.

A case series of superficial parotidectomy under local anesthesia

&lt;p class="abstract"&gt;&lt;span lang="EN-US"&gt;Superficial parotidectomy is the biopsy procedure of choice for all parotid neoplasm’s as well as therapeutic choice for small low-grade malignancies. The key to successful parotid surgery is identification of the facial nerve. It is usually done under general anesthesia (GA).The main focus in this procedure is to remove entire superficial parotid gland along with a disease and at the same time preventing any iatrogenic injury to facial nerve and its peripheral branches which supplies over the face. We present three cases of superficial parotidectomies done under local anesthesia technique. The objectives of these reports are to discuss the clinical presentation, diagnosis and management of these growths surgically under local as an alternative method or when it is desired under some special circumstances and the merits. This technique may avoid the use of facial nerve monitor.&lt;/span&gt;&lt;/p&gt;

Our Experience With Facial Nerve Monitoring in Vestibular Schwannoma Surgery Under Partial Neuromuscular Blockade

Introduction and objectivesFacial nerve monitoring is fundamental in the preservation of the facial nerve in vestibular schwannoma surgery. Our objective was to analyse the usefulness of facial nerve monitoring under partial neuromuscular blockade. MethodsThis was a retrospective analysis of 69 patients operated in a tertiary hospital. ResultsWe monitored 100% of the cases. In 75% of the cases, we could measure an electromyographic response after tumour resection. In 17 cases, there was an absence of electromyographic response. Fifteen of them had an anatomic lesion with loss of continuity of the facial nerve and, in 2 cases, there was a lesion with preservation of the nerve. Preoperative facial palsy (29% 7%; P=.0349), large tumour size (88 vs 38%; P=.0276), and a non-functional audition (88 vs 51%; P=.0276) were significantly related with an absence of electromyographic response. ConclusionsFacial nerve monitoring under neuromuscular blockade is possible and safe in patients without previous facial palsy. If the patient had an electromyographic response after tumour excision, they developed better facial function in the postoperative period and after a year of follow up.

Nuestra experiencia con la monitorización del nervio facial en cirugía del schwannoma del vestibular bajo bloqueo neuromuscular parcial

Introduction and objectivesFacial nerve monitoring is fundamental in the preservation of the facial nerve in vestibular schwannoma surgery. Our objective was to analyse the usefulness of facial nerve monitoring under partial neuromuscular blockade. MethodsThis was a retrospective analysis of 69 patients operated in a tertiary hospital. ResultsWe monitored 100% of the cases. In 75% of the cases, we could measure an electromyographic response after tumour resection. In 17 cases, there was an absence of electromyographic response. Fifteen of them had an anatomic lesion with loss of continuity of the facial nerve and, in 2 cases, there was a lesion with preservation of the nerve. Preoperative facial palsy (29% 7%; P=.0349), large tumour size (88 vs. 38%; P=.0276), and a non-functional audition (88 vs. 51%; P=.0276) were significantly related with an absence of electromyographic response. ConclusionsFacial nerve monitoring under neuromuscular blockade is possible and safe in patients without previous facial palsy. If the patient had an electromyographic response after tumour excision, they developed better facial function in the postoperative period and after a year of follow up.

Usefulness of facial nerve monitoring for confirmation of greater superficial petrosal nerve in anterior transpetrosal approach.

The greater superficial petrosal nerve (GSPN) is especially important in anterior transpetrosal approach (ATPA) as the most reliable superficial landmark of Kawase's triangle. The GSPN can be considered as the superficial lateral border of anterior petrosectomy on the middle fossa to avoid internal carotid artery (ICA) injury. Although experienced operators can find the GSPN, its confirmation is not always easy to achieve. We introduce our recent GSPN confirmation methods using facial nerve monitoring. In 10 recent cases, antidromic GSPN stimulation and free-running facial muscle electromyography (EMG) monitoring were performed. Facial nerve evoked-EMG by antidromic GSPN stimulation confirmed the location of the GSPN course with precision in all cases. Free-running facial muscle EMG informed the mechanical stress of facial nerves through the GSPN. There was no postoperative facial palsy or dry eye in these cases. GSPN confirmation and preservation are not always easy to achieve. These monitoring methods are useful for the confirmation of the GSPN, which is a landmark for safe extradural anterior petrosectomy, and for the preservation of the GSPN itself.

Contemporary Changes with the Use of Facial Nerve Monitoring in Chronic Ear Surgery

There is a growing trend for the routine use of the facial nerve monitor (FNM) in chronic ear surgery. We aimed to examine current patterns in the use of FNMs in chronic ear surgery. Descriptive design (survey). Academic health center. A 10-question survey was designed to identify level of training, scope of practice, specific otologic surgeries where monitoring was most used, and the opinion of respondents regarding the use of FNMs as standard of care for chronic and/or middle ear surgery. A randomized list of 2000 board-certified members of the American Academy of Otolaryngology-Head and Neck Surgery was generated. One thousand subjects received a mailed survey with a self-addressed return envelope and 1000 subjects received an emailed survey through Surveymonkey.com. There were 359 (36%) surveys returned by mail and 258 (26%) surveys returned electronically. Forty-three percent of respondents were in private practice, and 31% were fellowship trained in otology/neurotology. Sixty-five percent used a FNM in their training and 95% had regular access to a FNM. Revision mastoid surgery, cholesteatoma, canal wall down mastoidectomy, and facial recess approach were the settings where a FNM was most used. Forty-nine percent of respondents felt that a FNM should be used as the standard of care in chronic ear surgery; this represents an increase from 32% in a similar study done approximately 10 years ago. There is a growing trend for routine facial nerve monitoring in the setting of chronic ear surgery.

Excision of vestibular schwannomas – is there a learning curve and how best to demonstrate it?

Objective. To demonstrate the existence of a learning curve in a consultant neurosurgeon's performance in excising vestibular schwannomas by plotting the cumulative sum (CUSUM) chart. Also, to evaluate the influence of new technology in the form of the facial nerve monitor (FNM) and the KTP-532 Laser on surgical performance.Method. Analysis was carried out on a prospectively collected data series of 102 consecutive cases of vestibular schwannomas excisions between 1986 and 2000 by a single neurosurgeon using the retrosigmoid approach. The CUSUM score chart of the surgical outcomes across the series was plotted for all and large tumour sizes separately. The changes in CUSUM scores were assessed using statistical change-point analysis. Using the multivariate logistic regression analysis, we inspected the association between use of FNM and laser on outcome.Results. After the first 27 cases and coinciding with the introduction of the FNM there was a clear change in the direction of the slope of the CUSUM chart, showing a clear improving trend in performance (p = 0.09). The same phenomenon was also seen when plotting the CUSUM chart for large tumours only, although this was not statistically significant. The use of FNM reduces the risk of bad House Brakmann-score by approximately 90% for all tumours (risk of bad outcome with FNM = 3.2% and without FNM = 26.7%, odds ratio = 0.10 and 95% confidence interval (0.02–0.61), p = 0.013) after adjusting for age at operation, but no significant association was seen with the use of laser.Conclusion. There appears to be a learning curve in the performance of a neurosurgeon. Compared to previous reports of sequential block analysis, the CUSUM method is less arbitrary and more transparent. The CUSUM is most useful as an audit tool that can help spare patients from undesirable learning curves, and help to demonstrate good standards in appraisal and revalidation.

Patterns of Use of Facial Nerve Monitoring During Parotid Gland Surgery

To determine current patterns of use of facial nerve monitoring during parotid gland surgery by otolaryngologists in the United States. A questionnaire encompassing surgeon training background, practice setting, patterns of facial nerve monitor usage during parotid gland surgery, and history of permanent facial nerve injury or legal action resulting from parotid surgery was mailed to 3139 otolaryngologists in the United States. Associations between facial nerve monitor usage and dependent variables were examined by using the chi(2) test. Magnitudes of the associations were determined from odds ratios calculated using logistic regression. A 49.3% questionnaire response rate was achieved. Sixty percent of respondents who perform parotidectomy employed facial nerve monitoring some or all of the time. Respondents were 5.6 times more likely to use the monitor in practice if they used it in training and 79% more likely to use it if they performed more than 10 parotidectomies per year. Respondents were 35% less likely to have a history of inadvertent nerve injury if they performed more than 10 parotidectomies per year. Surgeons who employed monitoring in their practice were 20.8% less likely to have a history of a parotid surgery-associated lawsuit. Additional information regarding surgeon demographics, types of nerve monitors used, and reasons for and against monitor usage are discussed. Permanent facial nerve paralysis after parotidectomy occurs in 0-7% of cases. Currently, a majority of otolaryngologists in the United States are employing facial nerve monitoring during parotid surgery some or all of the time, even though no studies to date have demonstrated improved outcomes with its use. Physician training background and surgery caseload were significant factors influencing usage of facial nerve monitoring in this study.

An objective assessment of the advantages of retrograde parotidectomy

Objective This study was undertaken to determine whether the retrograde parotidectomy approach is more efficient than standard anterograde parotidectomy without compromise of surgical effectiveness. Methods A retrospective analysis of patients undergoing parotidectomy was conducted. Cases were divided into those undergoing retrograde facial nerve dissection and those undergoing standard anterograde facial nerve dissection. From the review of medical records, standard demographic information, surgical time, histopathology, estimated blood loss, and use of facial nerve monitoring were determined. Pathology was reviewed to determine the size of the overall resection specimen as well as the size of the lesion excised and margin status. Postoperative complications were also recorded. Statistical comparisons were conducted between these 2 approaches for these clinical variables such as surgical time, blood loss, tumor margin status and relative volume of tissue removed during parotidectomy. Results 45 patients undergoing parotidectomy met inclusion criteria. The average patient age was 50.8 years with a female preponderance (73%). There were 19 standard parotidectomies and 26 retrograde approaches. Compared to standard parotidectomy, retrograde parotidectomy consumed less operative time (3.2 versus 1.8 hours, respectively), decreased intraoperative blood loss (67.9 cc versus 40.3 cc, respectively), and resulted in less removal of normal parotid tissue (volume of normal parotid tissue removed in excess of tumor: 23.0 cc versus 6.0 cc, respectively). No significant difference in surgical margin status was noted between anterograde and retrograde parotidectomy ( P = 0.452). Conclusions In appropriately selected cases, compared with standard anterograde parotidectomy, retrograde parotidectomy is more efficient and spares normal parotid tissue without compromising surgical margins. Facial nerve monitoring provides a useful adjunct for retrograde dissection.

Patterns of use of facial nerve monitoring during parotid gland surgery

Objectives: The purpose of this study was to determine current patterns of use of facial nerve monitoring during parotid gland surgery by otolaryngologists in the United States. Methods: A questionnaire encompassing training background, practice setting, patterns of facial nerve monitor usage during parotid surgery, and history of permanent facial nerve injury or legal action resulting from parotid surgery was mailed to 3139 otolaryngologists in the United States. Associations between monitor usage and dependent variables were examined using X2 tests, and magnitudes of associations were determined with odds ratios calculated using logistic regression. Results: A 49.3% questionnaire response rate was achieved. Sixty percent of respondents who perform parotidectomy used facial nerve monitoring some or all of the time. Respondents were 5.6% more likely to use the monitor in practice if they used it in training and 79% more likely to use it if they performed over 10 parotidectomies per year. Respondents were 35% less likely to have a history of inadvertant nerve injury if they did more than 10 parotidectomies per year. Surgeons who used monitoring in their practice were 20.8% less likely to have a history of parotid surgery-associated lawsuit. Additional information regarding demographics, type of nerve monitors used, and reasons for and against monitor usage are discussed. Conclusions: Permanent facial nerve paralysis following parotidectomy occurs in 0%-7% of cases. Consequently, a majority of otolaryngologists are turning to facial nerve monitoring during parotid surgery to reduce this complication rate even further. Physician training and surgery caseload are significant factors influencing usage of facial nerve monitoring.

Management of congenital atresia ear

A total of 3 out of 5 cases of major congenital ear malformation seen in out patient department in two years in 1997 and 1998 were operated for functional reconstruction of external auditory canal, middle car and ossicular chain. 2 cases of bilateral malformation of auricle grade 2 were advised otoplastic repair prior to tympanoplasty. Out of the 3 cases operated by anterior transatretic bone approach, 2 cases had good hearing improvement in air conduction threshold of up to 30 db hearing level (averages of 0.5, 1.2 and 3 khz). One case developed external canal stenosis by six months post operatively and drop in hearing. There was no facial nerve injury in any of the cases. This paper analyses the importance of facial nerve delineation preoperatively based on its embryological development and ils relationship with temporal bone and membranous labyrinth. It also focuses on the various parameters like timing of surgery, importance of (CT) scanning, use of facial nerve monitor and surgical expertise and experience which govern the surgical intervention and its results in congenital car atresia.

Technique and pitfalls of facial nerve monitoring

The routine use of facial nerve monitoring is controversial. Several investigators advocate the routine use of facial nerve monitoring devices; however, there are no studies to date that prove their effectiveness. There is little in the literature discussing the proper technique and the pitfalls of monitoring. This discussion is critical in making the techniques of facial nerve monitoring safe and effective. Only when more standardized techniques are adopted can the question of usefulness be answered.

Utilidad de la monitorización del nervio facial en la cirugía de la glándula parótida

ObjectiveTo analyse the usefulness of facial nerve monitoring by continuous electromyography during parotidectomy.Patients and methods: Fifty-two consecutive patients who underwent parotidectomy (27 unmonitored and 25 monitored) between 1987 and 1998. Both groups had a similar distribution of superficial and total parotidectomy. ResultsFacial nerve monitoring reduced the incidence and severity of facial nerve paralysis independently of the kind of surgery performed. The incidence of temporary facial paralysis was significantly lower in the monitored group (36%) than in the unmonitored group (70%) (p=0.013). The rates of permanent deficit were 4% for the monitored group and 30% for the unmonitored group (p=0.025). ConclusionsThe results suggest that intraoperative facial nerve monitoring reduces the incidence of postoperative facial deficit. The routine use of facial nerve monitoring is controversial. However, it is considered useful in surgery where there is a higher risk of injury to the facial nerve such as total parotidectomy, re-interventions or chronic inflammatory conditions.

Postparotidectomy facial nerve paralysis: possible etiologic factors and results with routine facial nerve monitoring.

Analyze the incidence and factors responsible for postparotidectomy facial nerve paralysis when the surgery is performed with the routine use of facial nerve monitoring. A prospective, nonrandomized study. Seventy consecutive patients underwent parotidectomy with intraoperative facial nerve monitoring. Two devices were used: a custom mechanical transducer and a commercial electromyograph-based apparatus. All patients were analyzed, including those with cancer and those with deliberate or accidental sectioning of facial nerve branches. The outcome variables were the motor facial nerve function according to the House-Brackmann grading scale (HB) at 1 week (temporary paralysis) and 6 to 12 months (definitive paralysis). Facial nerve grading was performed blindly from reviewing videotapes. The overall incidence of facial paralysis (HB>1) was 27% for temporary and 4% for permanent deficits. Most of the deficits were partial, most often concerning the marginal mandibular branch. Temporary deficits with HB scores of greater than 2 were only present in patients with parotid cancer or infection. Permanent deficits were present in three patients, including one patient with facial nerve sacrifice. Factors significantly associated with an increased incidence of temporary facial paralysis include the extent of parotidectomy, the intraoperative sectioning of facial nerve branches, the histopathology and the size of the lesion, and the duration of the operation. Despite a stringent accounting of postoperative facial nerve deficits, these data compare favorably to the literature with or without the use of monitoring. An overall incidence of 27% for temporary facial paralysis and 4% for permanent facial paralysis was found. Although the lack of a control group precludes definitive conclusions on the role of electromyograph-based facial nerve monitoring in routine parotidectomy, the authors found its use very helpful.