Facial nerve dysfunction after superficial parotidectomy with or without continuous intraoperative electromyographic neuromonitoring: a prospective randomized pilot study

Facial Nerve Injury after Extracapsular Dissection for Benign Parotid Tumors with and without Intraoperative Monitoring: A Retrospective Study of a Single Center

BACKGROUND

Facial nerve injury (FNI) is the most common complication of parotid surgery and manifests as FN paralysis. The use of intraoperative facial nerve monitoring (IFNM) is becoming an established intraoperative aid for surgeons, assisting in the identification of the location and dissection of the facial nerve trunk or branches. The postoperative outcomes of parotid surgery with and without monitoring have been addressed in only a limited number of studies.

OBJECTIVE

The objective of this study is to evaluate the incidence of postoperative paralysis in patients undergoing extracapsular dissection (ED) for benign parotid tumors concerning the use or non-use of IFNM.

MATERIALS AND METHODS

The retrospective study was conducted at the Maxillo-Facial Department of the Magna Graecia University of Catanzaro. The patients were divided into two groups: Group 1 consisted of patients who underwent surgery without IFNM (1 January 2015 to 31 December 2018); Group 2, on the other hand, consisted of patients who underwent surgery with IFNM (1 January 2019 to 31 December 2022). Group 2 employed the Nerve Integrity Monitor (Medtronic's NIM®). To classify the FN function, we employed the modified House-Brackmann classification system. To evaluate the dependence between the "use of IFNM" and "postoperative paralysis", a descriptive analysis was conducted, including applying the Chi-squared test and calculating the Pearson correlation. Subsequently, a binary logistic regression model was applied to further evaluate the correlation between the latter. The level of statistical significance was set at p < 0.05.

RESULTS

A total of 276 patients were included in the study: 120 subjects were assigned to Group 1 (43.5%, comprising 60 men and 60 women) and 156 subjects were assigned to Group 2 (56.5%, comprising 93 men and 63 women). In 91.7% of the cases (n. 253, precisely 105 in Group 1 and 148 in Group 2), no FNI occurred. In 8.33% of the cases (n. 23, specifically 15 in Group 1 and 8 in Group 2), postoperative paralysis was observed. Of these subjects, only two in Group 1 had permanent paralysis (8.69%); therefore, 91.31% had transient paralysis. As a result, 91.31% of the subjects exhibited transient paralysis. In the case of FNI, 78% of the cases involved the marginal mandibular branch (n. 18), 13% involved the temporo-zygomatic branch (n. 3), and 7% involved more than one branch (n = 2). The results of the multivariable binary logistic regression analysis demonstrated that the use of IFNM was a statistically significant influencing factor, with an estimated reduction in postoperative paralysis of approximately 62% (OR 0.378; 95% CI: 0.155-0.92). In Group 2, the occurrence of transient complications was significantly reduced (OR 0.387; 95% CI: 0.149-1.002 with p < 0.05).

DISCUSSION AND CONCLUSIONS

The use of IFNM in the ED for benign parotid tumors significantly reduces the rate of FNI and, consequently, postoperative FN paralysis. On the other hand, the use of monitoring systems must not replace the experience and anatomical knowledge of the surgeon.

Impact of Surgeon's Experience and Tumor's Nature in the Use of Intraoperative Facial Nerve Monitoring in Superficial Parotidectomy. Preliminary Results from a Single-Center Retrospective Analysis

To assess the effectiveness of intraoperative facial nerve monitoring (IFNM) compared to non-monitoring in the prevention of post-operative facial nerve palsy during superficial parotidectomy. Patients treated with curative intent for parotid gland tumors between January 2020 and January 2022 were included. The study population has been divided in 2 groups, based on IFNM: the group A included patients operated with IFNM, whilst group B was the non-monitoring group. A further classification focused on the pathologies and the surgeons' experience. The study group included 58 patients, 27 female and 31 male. The mean age was 45.7 yr (range 36-78). No statistical difference has been found in post-operative HB grade between group A and B. The analysis of patients affected by pleomorphic surface lobe adenomas of the parotid did not show a statistical difference in HB outcome (p > 0.05). The analysis of the effect of surgeons' experience in IFNM advantage did not show statistical difference for superficial parotid tumors. The results of the present study suggest that the use of IFNM during parotid surgery is not mandatory to preserve the VII nerve function, both in case of primary tumor and in case of recurrence, and even when surgery is performed by less experienced surgeon compared to those cases treated by a more experienced surgeon.

Development of a Machine Learning Algorithm to Forecast the Likelihood of Postoperative Neurological Complications in Patients With Parotid Tumors

Objective: The objective of this study was to create and verify a machine learning-driven predictive model to forecast the likelihood of facial nerve impairment in patients with parotid tumors following surgery. Methods: We retrospectively collected data from patients with parotid tumors between 2013 and 2023 to develop a prediction model for postoperative facial nerve dysfunction using 5 ML techniques: Logistic Regression (Logit), Random Forest (RF), XGBoost (XGB), Artificial Neural Network (ANN), and Support Vector Machine (SVM). Predictor variables were screened using binomial-LASSO regression. Results: The study had a total of 403 participants, out of which 56 individuals encountered facial nerve damage after the surgery. By employing binomial-LASSO regression, we have successfully identified 8 crucial predictive variables: tumor kind, tumor pain, surgeon's experience, tumor volume, basophil percentage, red blood cell count, partial thromboplastin time, and prothrombin time. The models utilizing ANN and Logit achieved higher area under the curve (AUC) values, namely 0.829, which was significantly better than the SVM model that had an AUC of 0.724. There were no noticeable disparities in the AUC values between the ANN and Logit models, as well as between these models and other techniques like RF and XGB. Conclusion: Using machine learning, our prediction model accurately predicts the likelihood that patients with parotid tumors may experience facial nerve damage following surgery. By using this model, doctors can assess patients' risks more accurately before to surgery, and it may also help optimize postoperative treatment techniques. It is anticipated that this tool would enhance patients' quality of life and therapeutic outcomes.

Surgical management of Warthin tumor: long-term follow-up of 224 patients from 2002 to 2018

PURPOSE

Warthin tumors (WT) are the second most common benign parotid gland neoplasms. They can occur as synchronous or metachronous lesions in 6-10% of cases. This study aims to compare the complication rate in 224 patients who underwent extracapsular dissection (ECD) or superficial parotidectomy (SP) for the treatment of a WT.

METHODS

This retrospective study was conducted at the Department of Maxillo-Facial Surgery at the University of Naples "Federico II" from February 2002 to December 2018 on a group of patients who underwent surgical treatment for WT. The type of surgical technique was chosen based on Quer's classification. The complications evaluated were facial nerve palsy, hematoma, Frey's syndrome, and bleeding.

RESULTS

A total of 224 patients treated from 2002 to 2018 for Warthin tumor were included in the study. Two hundred elven had solitary tumors (94.1%) and 13 had multicentric lesions (5.8%), of which 9 cases presented synchronous lesions and 4 cases presented metachronous lesions. Extracapsular dissection (ECD) was performed in 130 patients (58.3% of cases) and superficial parotidectomy (SP) in the other 94 (41.7% of cases).

CONCLUSIONS

We consider both surgical techniques as valid. In our opinion, it is essential to study each case based on Quer's Classification to obtain the best surgical outcome. Based on a lower observed rate of complications such as facial nerve palsy, Frey's syndrome, and bleeding, ECD seems to be the best option for the surgical treatment of Quer Class I lesions.

Post-parotidectomy facial nerve rehabilitation outcomes: Comparison between benign and malignant neoplasms

BACKGROUND

Facial nerve dysfunction can be a devastating trouble for post-parotidectomy patients.

OBJECTIVE

To assess rehabilitation outcomes concerning patients with post-parotidectomy facial nerve dysfunction, comparing benign versus malignant neoplasms.

METHODS

Prospective study enrolling adults who underwent parotidectomy with facial nerve sparing between 2016 and 2020. The Modified Sunnybrook System (mS-FGS) was used for facial assessments. Physiotherapy began on the first post-operative day with a tailored program of facial exercises based on Neuromuscular Retraining, to be performed at home 3 times/day. From the first outpatient consultation, Proprioceptive Neuromuscular Facilitation was added to the treatment of cases with moderate or severe facial dysfunctions.

RESULTS

Benign and malignant groups had a statistically significant improvement in mS-FGS (p < 0.001 and p = 0.005, respectively). There was no significant difference between groups regarding treatment duration or number of physiotherapy sessions performed. The history of previous parotidectomy resulted in more severe initial dysfunctions and worse outcome. Age over 60 years and initially more severe dysfunctions impacted the outcome.

CONCLUSION

Patients with benign and malignant parotid neoplasms had significant and equivalent improvement in postoperative facial dysfunction following an early tailored physiotherapy program, with no significant difference in the final facial score, treatment duration, or number of sessions required.

Facial nerve monitoring in parotid gland surgery: Design and feasibility assessment of a potential standardized technique

Background

Even though the use of nerve monitoring during parotid gland surgery is not the gold standard to prevent damage to the nerve, it surely offers some advantages over the traditional approach. Different from thyroid surgery, where a series of steps in intraoperative nerve monitoring have been described to confirm not only the integrity but-most importantly-the function of the recurrent laryngeal nerve, in parotid gland surgery, a formal guideline to follow while dissecting the facial nerve has yet to be described.

Methods

A five-year retrospective study was done reviewing the intraoperative records of patients who underwent parotid gland surgery under neural monitoring. The operative findings regarding the neuromonitoring process, particularly in regard to the amplitude of two main branches, were revised. A literature search was done to search for guidelines to follow when a facial nerve loss of signal is encountered.

Results

Fifty-five patients were operated on using the Nim 3 Nerve Monitoring System (Medtronic); 31 were female patients, and 47 patients had benign lesions. Minimum changes were observed in the amplitude records after a comparison was made between the first and the last stimulation. There were only three articles discussing the term loss of signal during parotid gland surgery.

Conclusion

Today, no sufficient attention has been given to the facial nerve monitoring process during parotidectomy. This study proposes a formal guideline to follow during this procedure as well as an instruction to consider when a loss of signal is observed to develop a uniform technique of facial nerve stimulation.

Predicting postoperative facial nerve paralysis by using intraoperative nerve monitoring during parotid surgery

OBJECTIVES

To investigate a method for predicting postoperative facial nerve paralysis (POFNP) during parotid surgery using intraoperative nerve monitoring (IONM).

METHODS

We assessed prediction for POFNP by using IONM, comparing between stimulation in the facial nerve trunk and each branch by using facial nerve monitoring. The amplitude response ratio (ARR) was calculated for the trunk/periphery. In addition, we then examined the correlation between ARR and time to recovery of paralyzed branches.

RESULTS

372 branches of 93 patients did not develop POFNP and were classified as group A. Among 20 patients who developed POFNP, 51 branches without POFNP were classified as group B, and 29 branches with POFNP were classified as group C. The ARR was approximately 1 in group A and B. but less than 0.5 in all branches in Group C. When the cut off value of ARR was set at 0.55, the sensitivity, specificity, and accuracy of POFNP diagnosis by ARR were 96.5%, 93.1%, and 96.8%, respectively.

CONCLUSION

Using IONM during parotid surgery enables easy prediction of POFNP.

Feasibility of facial nerve monitoring using adhesive surface electrodes during parotidectomy: a comparative study with needle electrodes

PURPOSE

Electrophysiological monitoring of the facial nerve during parotidectomy has been reported as an adjunctive method to prevent facial nerve injury. Classically, a needle electrode is used to obtain electromyographic (EMG) signals from facial muscles during facial nerve monitoring (FNM) of parotid surgery, likewise adhesive surface electrodes. This study aimed to investigate the feasibility of performing FNM with surface electrodes during parotid surgery and to compare EMG values with needle electrodes.

METHODS

Thirty patients who underwent parotidectomy under FNM using adhesive surface and needle electrodes were included. Two pairs of adhesive surface electrodes and needle electrodes were used for FNM during parotid surgery. Mean amplitudes were collected after electrical facial nerve stimulation at 1 mA after specimen removal.

RESULTS

The mean amplitude of the adhesive surface electrodes was 226.50 ± 118.44 μV (orbicularis oculi muscle) and 469.6 ± 306.06 μV (orbicularis oris muscle), respectively. The mean amplitude of the needle electrodes was 449.85 ± 248.10 μV (orbicularis oculi muscle) and 654.66 ± 395.71 μV (orbicularis oris muscle), respectively. The mean amplitude of the orbicularis oris muscle was significantly greater than that of the orbicularis oculi. The amplitude values measured in the orbicularis oculi muscle showed significant differences between the needle and skin electrodes.

CONCLUSIONS

Facial nerve monitoring (FNM) using adhesive surface electrodes is feasible in parotid surgery. Although the mean amplitude value of the surface electrode was relatively lower than that of the needle electrode, the surface electrode is considered a feasible and safe EMG recording device for FNM in parotid surgery.

Facial nerve dysfunction following parotidectomy: role of intraoperative facial nerve monitoring

PURPOSE

Facial nerve dysfunction (FND) is a frequent and serious parotidectomy outcome. Intraoperative facial nerve monitoring (IFNM) is an increasingly used technique to identify the facial nerve (FN) and minimize its injury. This study aimed to evaluate the determinant factors in the presence and severity of FND after parotidectomy, including IFNM.

STUDY DESIGN, SETTING AND METHODS

A total of 48 patients consecutively submitted to parotidectomy between 2005 and 2020 in a tertiary hospital were retrospectively analyzed. The House-Brackmann Scale (HBS) was used to assess the severity of FND.

RESULTS

There was a mean age of 54.2 ± 17.8 years, 50% were male. Pleomorphic adenoma (41.7%) and Warthin's tumor (25.0%) were most common. From the 23 patients (47.9%) who developed some degree of FND (HBS score of 3.41 ± 1.53), 19 (82.6%) showed facial movement recovery, with a mean recovery time of 4.78 ± 2.53 months. IFNM was performed in 39.6% of the surgeries. The use of IFNM (p = 0.514), the type of surgery-partial or total parotidectomy-(p = 0.853) and the type of histology-benign or malignant lesion-(p = 0.852) did not significantly influence the presence of FND in the postoperative period. However, in the subgroup of patients who developed FND, the HBS value was significantly lower in cases of benign pathology (p = 0.002) and in patients who underwent IFNM (p = 0.017), denoting a significantly lower severity.

CONCLUSION

In the present study, IFNM and the existence of a benign lesion have been shown to be associated with lower severity of FND.

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.

Patient safety and quality improvements in parotid surgery

Parotidectomy is the mainstay treatment for tumors of the parotid gland. In an effort to improve clinical outcomes, several modern surgical techniques and perioperative interventions have been evaluated and refined. This review discusses current and actively debated perioperative interventions aimed at improving patient safety and the quality of parotidectomy. Relevant high-impact literature pertaining to preoperative diagnostic modalities, intraoperative surgical techniques, and postoperative care will be described.

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.

Correlation between Electrophysiological Change and Facial Function in Parotid Surgery Patients

This observational study investigated intraoperative electrophysiological changes and their correlation with postoperative facial expressions in parotidectomy patients with visual confirmation of facial nerve (FN) continuity. Maximal electromyography(EMG) amplitudes of the facial muscles corresponding to temporal, zygomatic, buccal and mandibular branches were compared before/after FN dissection, and facial function at four facial regions were evaluated before/after parotidectomy in 112 patients. Comparisons of 448 pairs of EMG signals revealed at least one signal decrease after FN dissection in 75 (67%) patients. Regional facial weakness was only found in 13 of 16 signals with >50% amplitude decreases. All facial dysfunctions completely recovered within 6 months. EMG amplitude decreases often occur after FN dissection. An amplitude decrease >50% in an FN branch is associated with a high incidence of dysfunction in the corresponding facial region. This study tries to establish a standard facial nerve monitoring (FNM) procedure and a proper facial function grading system for parotid surgery that will be useful for the future study of FNM in parotid surgery.

Management of Salivary Gland Malignancy: ASCO Guideline

PURPOSE

To provide evidence-based recommendations for practicing physicians and other healthcare providers on the management of salivary gland malignancy.

METHODS

ASCO convened an Expert Panel of medical oncology, surgical oncology, radiation oncology, neuroradiology, pathology, and patient advocacy experts to conduct a literature search, which included systematic reviews, meta-analyses, randomized controlled trials, and prospective and retrospective comparative observational studies published from 2000 through 2020. Outcomes of interest included survival, diagnostic accuracy, disease recurrence, and quality of life. Expert Panel members used available evidence and informal consensus to develop evidence-based guideline recommendations.

RESULTS

The literature search identified 293 relevant studies to inform the evidence base for this guideline. Six main clinical questions were addressed, which included subquestions on preoperative evaluations, surgical diagnostic and therapeutic procedures, appropriate radiotherapy techniques, the role of systemic therapy, and follow-up evaluations.

RECOMMENDATIONS

When possible, evidence-based recommendations were developed to address the diagnosis and appropriate preoperative evaluations for patients with a salivary gland malignancy, therapeutic procedures, and appropriate treatment options in various salivary gland histologies.Additional information is available at www.asco.org/head-neck-cancer-guidelines.

Best Practices in Facial Nerve Monitoring

OBJECTIVES/HYPOTHESIS

Facial nerve monitoring (FNM) has evolved into a widely used adjunct for many surgical procedures along the course of the facial nerve. Even though majority opinion holds that FNM reduces the incidence of iatrogenic nerve injury, there are few if any studies yielding high-level evidence and no practice guidelines on which clinicians can rely. Instead, a review of the literature and medicolegal cases reveals significant variations in methodology, training, and clinical indications.

STUDY DESIGN

Literature review and expert opinion.

METHODS

Given the lack of standard references to serve as a resource for FNM, we assembled a multidisciplinary group of experts representing more than a century of combined monitoring experience to synthesize the literature and provide a rational basis to improve the quality of patient care during FNM.

RESULTS

Over the years, two models of monitoring have become well-established: 1) monitoring by the surgeon using a stand-alone device that provides auditory feedback of facial electromyography directly to the surgeon, and 2) a team, typically consisting of surgeon, technologist, and interpreting neurophysiologist. Regardless of the setting and the number of people involved, the reliability of monitoring depends on the integration of proper technical performance, accurate interpretation of responses, and their timely application to the surgical procedure. We describe critical steps in the technical set-up and provide a basis for context-appropriate interpretation and troubleshooting of recorded signals.

CONCLUSIONS

We trust this initial attempt to describe best practices will serve as a basis for improving the quality of patient care while reducing inappropriate variations.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:S1-S42, 2021.

Assessment of eye closure and blink with facial palsy: A systematic literature review

Facial palsy can cause the impairment of eye closure and affect blink, ocular health, communication, and esthetics. Dynamic surgical procedures can restore eye closure in patients with decreased facial nerve function. There are no standardized measures of voluntary and spontaneous eye closure that are used to evaluate the outcomes of blink restoration procedures. The purpose of this systematic literature review was to identify the measures used to assess normal and abnormal eye closure and blinking in patients with facial palsy. A literature search of the PubMed database using the keyword "facial nerve/surgery" was conducted. Only English language articles that pertain to the use of facial paralysis assessment systems published in the past 20 years, which involve eyelid closure were included. There were 57 articles that used a facial paralysis classification system with an eyelid closure component: House-Brackmann Facial Nerve Grading Scale (n = 43, 67%); Sunnybrook Facial Grading Scale (n = 9); palpebral fissure heights (n = 4), and the electronic clinician-graded facial function tool (n = 3) and three additional measures were reported once. Although the Terzis and Bruno Scoring System, blink ratio, and electronic, clinician-graded facial function scale(eFACE) Clinician-Graded Scoring System were valid measures of eyelid closure, there was no one comprehensive eye assessment that demonstrated all aspects of eye closure in facial palsy, which include closure amplitude, spontaneity, and quality of life. For blink assessment, eFACE is the most comprehensive tool currently available and recommended to be used with a patient-reported quality of life supplement that captures the specific domains related to facial nerve dysfunction.

Prospective outcomes following drainless superficial parotidectomy with sternocleidomastoid flap reconstruction

Background

Patients undergoing superficial parotidectomy for benign parotid lesions are at risk of postoperative complications, most notably cosmetic complications such as facial paralysis and contour defects, and functional complications including Frey’s syndrome. Traditionally, surgical drains have been placed at the end of surgery to prevent hematoma and sialocele formation. However, this can increase the risk of postoperative complications and contribute to a prolonged course in hospital. To try and prevent these risks and complications, we introduced a novel technique of a drainless parotidectomy by reconstructing the resulting parotid bed defect with a superiorly based sternocleidomastoid (SCM) rotational flap and by placement of gelfoam into the wound bed and a facelift dressing postoperatively to provide additional hemostasis and avoid drain placement.

Methods

All patients with benign parotid disease undergoing a drainless superficial parotidectomy and reconstruction with a superiorly based SCM rotational flap at our center were identified within a prospective cohort database between July 2010–2018. Primary outcomes included postoperative cosmetic and functional outcomes, complications and length of hospital stay. A secondary cost analysis was done to compare this novel technique to traditional superficial parotidectomy with surgical drain placement.

Results

Fifty patients were identified within the database and were included in the final analysis. The average length of hospital stay was 1.02 days. All patients were satisfied with their aesthetic outcome at 1 year. During long term follow-up, 63% of patients reported normal appearance of the operated side. Seven patient’s (14%) developed temporary facial paresis following surgery. All patients had resultant normal facial function at follow-up in 1 year. No patients developed subjective Frey’s Syndrome. Two patients (4%) developed a postoperative sialocele requiring drainage and one patient (2%) developed a hematoma on extubation requiring evacuation and drain placement. Cost analysis demonstrated a cost savings of approximately $975 per person following surgery.

Conclusion

In the current study, we introduced a novel approach of a drainless superficial parotidectomy using a superiorly based SCM flap, gelfoam and placement of a post-operative facelift dressing. This drainless approach was associated with good long-term cosmetic and functional outcomes with few postoperative complications. This new technique may also offer the potential for long-term savings to the health care system.

Effectiveness of intraoperative facial nerve monitoring and risk factors related to postoperative facial nerve paralysis in patients with benign parotid tumors: A 20-year study with 902 patients

OBJECTIVE

We examined the incidence, risk factors, and recovery time for postoperative facial nerve paralysis in patients with benign parotid tumors and also investigated the usefulness of intraoperative facial nerve monitoring (FNM).

METHODS

Subjects were 902 patients with benign parotid tumors. Univariate and multivariate analyses were conducted for risk factors of postoperative facial nerve paralysis. We investigated the relationship between intraoperative FNM and postoperative facial nerve paralysis, and the recovery time for postoperative facial nerve paralysis according to tumor site.

RESULTS

Postoperative facial nerve paralysis occurred in 179 (19.8%) of 902 patients. Among them, 15.1%, 15.8%, and 37.5% had tumors in the superficial lobe, lower pole, and deep lobe, respectively. Paralysis risk factors were deep tumors, large tumors, long operation times, extensive bleeding, and non-use of FNM. Multivariate analysis determined female patients, deep tumors, and long operation times as significant risk factors, and female patients and deep tumors had an odds ratio of nearly 2. Use of intraoperative FNM resulted in a significantly lower incidence of facial nerve paralysis and was particularly useful in patients with superficial lobe tumors. Time to recovery from facial nerve paralysis was 6 months in 88% of the patients.

CONCLUSION

The incidence of paralysis should be kept as low as possible to enhance the postoperative quality of life of patients. The use of intraoperative FNM significantly lowered the incidence of paralysis in female patients with superficial tumors.

Factors associated with facial weakness following surgery for benign parotid disease: a retrospective multicenter study

BACKGROUND

Facial nerve weakness is the most common and most concerning complication after parotidectomy. Risk factors for this complication following surgery for benign diseases remain controversial.

OBJECTIVE

Review the frequency and prognosis of facial nerve weakness after parotidectomy and analyze potential risk factors.

DESIGN

Retrospective review of medical records.

SETTINGS

Two tertiary care centers.

PATIENTS AND METHODS

We included all parotidectomies performed for benign diseases from January 2006 to December 2018. Details about the development and recovery of postoperative facial weakness were recorded. Patient, disease and surgery-related variables were analyzed using bivariate and multivariate analyses to identify risk factors.

MAIN OUTCOME MEASURES

Frequency, recovery rates and risk factors for facial nerve weakness SAMPLE SIZE: 191 parotidectomies, 183 patients, 61 patients with facial weakness.

RESULTS

The frequency of postoperative facial weakness was 31.9% (61/191 parotidectomies). Among patients with temporary weakness, 90% regained normal facial movement within 6 months. Steroid therapy was not associated with a faster recovery. Postoperative weakness was not associated with age, diabetes, smoking, disease location, use of an intraoperative facial nerve monitor or direction of facial nerve dissection. Risk factors for temporary weakness were total parotidectomy and surgical specimens larger than 60 cubic centimeters. Revision surgery was the only identified risk factor for permanent weakness.

CONCLUSION

Larger parotid resections increase the risk of temporary facial nerve weakness while permanent weakness is mainly influenced by previous surgeries.

LIMITATIONS

Retrospective nature, underpowered sample size, selection bias associated with tertiary care cases.

CONFLICT OF INTEREST

None.

Facial nerve monitoring during parotid gland surgery: a systematic review and meta-analysis

INTRODUCTION

Facial nerve injury remains the most severe complication of parotid gland surgery. However, the use of intraoperative facial nerve monitoring (IFNM) during parotid gland surgery among Otolaryngologist-Head and Neck Surgeons continues to be a matter of debate.

MATERIALS AND METHODS

A systematic review and meta-analysis of the literature was conducted including articles from 1970 to 2019 to try to determine the effectiveness of intraoperative facial nerve monitoring in preventing immediate and permanent postoperative facial nerve weakness in patients undergoing primary parotidectomy. Acceptable studies included controlled series that evaluated facial nerve function following primary parotidectomy with or without intraoperative facial nerve monitoring.

RESULTS

Ten articles met inclusion criteria, with a total of 1069 patients included in the final meta-analysis. The incidence of immediate and permanent postoperative weakness following parotidectomy was significantly lower in the IFNM group compared to the unmonitored group (23.4% vs. 38.4%; p = 0.001) and (5.7% vs. 13.6%; p = 0.001) when all studies were included. However, when we analyze just prospective data, we are not able to find any significant difference.

CONCLUSION

Our study suggests that IFNM may decrease the risk of immediate post-operative and permanent facial nerve weakness in primary parotid gland surgery. However, due to the low evidence level, additional prospective-randomized trials are needed to determine if these results can be translated into improved surgical safety and improved patient satisfaction.

Safety of the "Saxophone®" electrode in parotid surgery for continuous intraoperative neuromonitoring of the facial nerve: results of a pro- and retrospective cohort study

Purpose

Early facial nerve palsy (eFNP) is the most frequent complication of the parotidectomy. Intraoperative neuromonitoring (IONM) in parotid surgery, which aims at reducing eFNP, has not evolved any further than the mere differentiation between the nerve and the surrounding tissue. Continuous IONM (cIONM), used in thyroid and posterior fossa surgery, has developed over the past years and has proved beneficial in reducing the rate of paresis in cases where a pattern of impending nerve injury is identified. In this study, we aim to demonstrate the safety of using the stimulating electrode (Saxophone^®) for cIONM in parotid surgery.

Methods

From 2016 to 2018, 40 patients who were referred for primary parotidectomy under cIONM according to our study protocol (registered at the German Clinical Trials Register, DRKS-ID: DRKS00011051, http://www.drks.de; http://apps.who.int/trialsearch) were included in this study. All patients with a normal preoperative facial nerve function [House–Brackman (HB)-Index 1] underwent surgery using continuous facial nerve stimulation with the Saxophone^® electrode (system AVALANCHE XT, Dr. Langer Medical, Waldkirch, Germany). A control group which underwent parotidectomies with only intermittent IONM was recruited from our records.

Results

Half of the patients in our study group suffered from eFNP. All except one regained normal facial nerve function within 6 months of surgery. There was no significant difference regarding eFNP when compared to the control group without cIONM (p = 0.11). No statistically significant correlation between the stimulation threshold (p = 0.74) or the duration of nerve stimulation and eFNP was found (p = 0.51).

Conclusion

We have demonstrated the safety of using the Saxophone^®-electrode for cIONM of the facial nerve in parotid surgery. Future development of this method could enable the recognition of impending nerve injury and thus reduce eFNP.

Role of Intraoperative Nerve Monitoring in Postoperative Muscle and Nerve Function of Patients Undergoing Modified Radical Mastectomy

This study aimed to postoperatively evaluate the effects of intraoperative neural monitoring (IONM) on muscles and nerves in patients who underwent modified radical mastectomy (MRM). In the 11 patients included in the study, nerves were determined and protected by nerve monitoring during the axillary dissection (IONM group). In another 11 patients, nerve monitoring was not performed; however, protection of the same nerves was attempted through careful nerve dissection (cautious nerve dissection [CND] group). The control group consisted of 22 healthy subjects. Muscle and nerve functions were blindly evaluated by an experienced physical therapy and rehabilitation specialist using electromyography (EMG) and ultrasonography (US) methods. The EMG values of the pectoralis major muscle were similar in the IONM and control groups (1.97 mV/1.98 mV, p = 0.97) but significantly lower in the CND group (1.57 mV, p < 0.05). Significant differences were found in the US values of the pectoralis major and minor muscles between the IONM and CND groups. No significant difference was found between the IONM and control groups in terms of EMG values of the serratus anterior muscle. This is the first prospective randomized study to objectively evaluate preservation of the nerve through nerve monitoring and its functional results. Monitoring of nerves during MRM is of great importance in terms of demonstrating the positive effects on muscle and nerve functions.