Temporary facial nerve dysfunction after parotidectomy correlates with tumor location

Intraoperative Facial Nerve Involvement in Parotid Tumours - A Retrospective Analysis in a Tertiary Care Centre

Purpose

The study aims to provide a comprehensive overview of the various malignant and benign parotid tumours and evaluate the predictive factors for intraoperative nerve involvement leading to facial palsy (FP).

Methods

It is a single-centre retrospective analysis for reviewing the involvement of facial nerve in post- parotidectomy patients. The clinical database from January 2012 to December 2020 was included in the study with a follow-up period of a minimum of 2 years. To maintain homogeneity, all squamous cell carcinomas of level 2 nodes involving parotid or residual/recurrent disease of the oral cavity requiring parotid dissection were excluded.

Results

A total of 248 patients (171 benign; 77 malignant) were evaluated with a mean age of 46.48 ± 10.76 years. The presence of malignancy increases the risk of FP (p = 0.027). 37 (14.92%) patients with FP were detected which included 34 with partial [32.35% in malignant; 62.16% in recurrent pleomorphic adenoma (RPA)] and 3 with total paralysis (66.67% in malignant; 33.33% in RPA). The recurrence of pleomorphic adenoma increases FP. While old age, larger size, hard fixed swelling with masseteric space (MS) infiltration appeared as risk factors for FP in malignant tumours (p = 0.047; p = 0.004; p < 0.00001 respectively).

Conclusion

Tumour size, malignancy, hard fixed mass, masseteric space infiltration, recurrence, and age > 45yrs have been statistically significant predictive factors for intraoperative facial nerve involvement leading to FP. The study also revealed that FP occurred more commonly when there was concurrent involvement of both superficial and deep lobes but was not statistically significant.

Tumor localization is the important factor for recovery time of postoperative facial nerve paralysis in benign parotid surgery

OBJECTIVE

Facial nerve paralysis is the most problematic complication of surgery for parotid tumors. This study aimed to examine the progress of recovery from postoperative transient facial nerve paralysis (POFNP).

METHODS

Participants were 203 patients who developed POFNP after benign parotid surgery. A Kaplan-Meier showed the progress of recovery from paralysis. Factors involved in recovery were examined. For factors for which a significant difference was found, recovery from paralysis was examined over time.

RESULTS

Rates of recovery from paralysis were as follows: 28.6% of patients at 1 month, 58.3% at 3 months, 85.9% at 6 months, and 95.1% at 12 months after surgery. Deep lobe tumors were shown to be significantly associated with delayed recovery from paralysis. The relationship between tumor location and the time of recovery from was that deep lobe tumors had a significantly worse recovery from paralysis at 4 and 5 months after surgery.

CONCLUSION

Patients who develop POFNP must be informed about the progress of recovery and factors involved in recovery from paralysis. We believe that the results of the present study are a useful reference to that end.

Facial nerve palsy following parotid gland surgery: A machine learning prediction outcome approach

Introduction

Machine learning (ML)-based facial nerve injury (FNI) forecasting grounded on multicentric data has not been released up to now. Three distinct ML models, random forest (RF), K-nearest neighbor, and artificial neural network (ANN), for the prediction of FNI were evaluated in this mode.

Methods

A retrospective, longitudinal, multicentric study was performed, including patients who went through parotid gland surgery for benign tumors at three different university hospitals.

Results

Seven hundred and thirty-six patients were included. The most compelling aspects related to risk escalation of FNI were as follows: (1) location, in the mid-portion of the gland, near to or above the main trunk of the facial nerve and at the top part, over the frontal or the orbital branch of the facial nerve; (2) tumor volume in the anteroposterior axis; (3) the necessity to simultaneously dissect more than one level; and (4) the requirement of an extended resection compared to a lesser extended resection. By contrast, in accordance with the ML analysis, the size of the tumor (>3 cm), as well as gender and age did not result in a determining favor in relation to the risk of FNI.

Discussion

The findings of this research conclude that ML models such as RF and ANN may serve evidence-based predictions from multicentric data regarding the risk of FNI.

Conclusion

Along with the advent of ML technology, an improvement of the information regarding the potential risks of FNI associated with patients before each procedure may be achieved with the implementation of clinical, radiological, histological, and/or cytological data.

Imaging of Facial Nerve With 3D-DESS-WE-MRI Before Parotidectomy: Impact on Surgical Outcomes

OBJECTIVE

The intra-parotid facial nerve (FN) can be visualized using three-dimensional double-echo steady-state water-excitation sequence magnetic resonance imaging (3D-DESS-WE-MRI). However, the clinical impact of FN imaging using 3D-DESS-WE-MRI before parotidectomy has not yet been explored. We compared the clinical outcomes of parotidectomy in patients with and without preoperative 3D-DESS-WE-MRI.

MATERIALS AND METHODS

This prospective, non-randomized, single-institution study included 296 adult patients who underwent parotidectomy for parotid tumors, excluding superficial and mobile tumors. Preoperative evaluation with 3D-DESS-WE-MRI was performed in 122 patients, and not performed in 174 patients. FN visibility and tumor location relative to FN on 3D-DESS-WE-MRI were evaluated in 120 patients. Rates of FN palsy (FNP) and operation times were compared between patients with and without 3D-DESS-WE-MRI; propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) were used to adjust for surgical and tumor factors.

RESULTS

The main trunk, temporofacial branch, and cervicofacial branch of the intra-parotid FN were identified using 3D-DESS-WE-MRI in approximately 97.5% (117/120), 44.2% (53/120), and 25.0% (30/120) of cases, respectively. The tumor location relative to FN, as assessed on magnetic resonance imaging, concurred with surgical findings in 90.8% (109/120) of cases. Rates of temporary and permanent FNP did not vary between patients with and without 3D-DESS-WE-MRI according to PSM (odds ratio, 2.29 [95% confidence interval {CI} 0.64-8.25] and 2.02 [95% CI: 0.32-12.90], respectively) and IPTW (odds ratio, 1.76 [95% CI: 0.19-16.75] and 1.94 [95% CI: 0.20-18.49], respectively). Conversely, operation time for surgical identification of FN was significantly shorter with 3D-DESS-WE-MRI (median, 25 vs. 35 min for PSM and 25 vs. 30 min for IPTW, P < 0.001).

CONCLUSION

Preoperative FN imaging with 3D-DESS-WE-MRI facilitated anatomical identification of FN and its relationship to the tumor during parotidectomy. This modality reduced operation time for FN identification, but did not significantly affect postoperative FNP rates.

Extracapsular Dissection of Deep Lobe Parotid Mass Aided by Retromandibular Vein on Imaging: A Case Report

This report investigates the use of the retromandibular vein on imaging as a diagnostic tool for planning deep lobe parotid tumors. A unique aspect of this case is the performance of extracapsular dissection on a deep lobe parotid lesion, which is rare. Preoperative imaging showed a superficially displaced retromandibular vein, indicating a deeply seated tumor, which aided surgical planning. Under general anesthesia, extracapsular dissection was performed while protecting the facial nerve branches. The patient's postoperative course was uneventful, and the facial nerve was intact with no weakness.

A retrospective study of parotid gland tumors at a single institution

The aim of the present study was to analyze the clinical characteristics, surgical treatments and clinical outcome of patients with parotid gland tumors and to compare the results with those cited in the literature. A retrospective study was conducted in 140 patients (male, n=77; female, n=63) with parotid gland tumors who underwent parotidectomy at Hokuto Hospital Department of Otolaryngology-Head and Neck Surgery (Obihiro, Japan) between April 2007 and December 2021. Of the 140 patients enrolled, 118 (84.3%) patients had benign tumors, including 63 (45%) patients with pleomorphic adenomas and 43 (30.7%) patients with Warthin tumors, and 22 patients (15.7%) had parotid carcinoma. Comparison of the three groups of patients with parotid gland tumors indicated that pack years as an indicator of smoking status were significantly higher in patients with Warthin tumors than in those with parotid carcinomas (P=0.011) or pleomorphic adenoma (P<0.001). Fine-needle aspiration cytology (FNAC) was non-diagnostic for only 6 (4.3%) of 140 patients. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of FNAC by both conventional smear and liquid-based cytology (LBC) for parotid carcinomas were 70, 99, 93.3, 94.4 and 82.9%, respectively. Among the 22 patients with parotid carcinoma, extended total/total and superficial parotidectomy were performed in 10 (45%) and 11 (50%) cases, respectively. Total and selective neck dissection of the area from level II to I, II and III were performed in 6 (24%) and 7 (32%) patients, respectively. Postoperative radiotherapy (50 Gy) was performed in 15 (68%) patients. The overall survival (OS) and disease-free survival (DFS) rates at 5 years were 51.5 and 76.4%, respectively. Univariate analysis revealed that age >65 years was significantly associated with poorer 5-year OS (P<0.001) and DFS (P<0.001). Multivariate analysis revealed that an age of more than 65 years combined with high-grade histologic malignancy was associated with worse DFS (P=0.02; hazard ratio, 3.628; 95% confidence interval, 1.283-9.514). In conclusion, the clinical characteristics and treatment outcomes of parotid gland tumors were consistent with the results of previous reports. Smoking may be closely related to the pathogenesis of Warthin tumors. LBC potentially provides improved accuracy in FNAC.

Pattern of facial nerve palsy during parotidectomy: a single-center experience

OBJECTIVE

This study was performed to report and analyze the prevalence of permanent facial nerve paralysis following parotidectomy for various benign and malignant lesions in a single center.

METHODS

This single-center retrospective study included all patients who underwent parotidectomy (total and superficial) for benign and malignant tumors and chronic inflammatory diseases during a 6-year period. Patients who had previously undergone an operation of the parotid gland and those with preoperative facial weakness were excluded.

RESULTS

The study included 127 patients ranging in age from 14 to 83 years (median, 45.89 years). Most patients were female (n = 83, 65.4%). The most prevalent procedure was superficial parotidectomy (n = 117, 92.1%), followed by total parotidectomy (n = 6, 4.7%). The average operative duration was 138 minutes (range, 80-400 minutes). Histopathology revealed that 109 (85.8%) patients had benign tumors, 14 (11.0%) had malignant tumors, and 4 (3.1%) had chronic sialadenitis. Only two patients sustained an injury to the cervical branch of the facial nerve.

CONCLUSION

In this single-center experience of parotid surgery, the rates of transient and permanent facial paralysis were acceptably low at 9.0% and 1.6%, respectively, for all pathologies.

Risk Factors of Postoperative Facial Palsy for Benign Parotid Tumors: Outcome of 1,018 Patients

OBJECTIVE

The aim of this study was to evaluate the rate of postoperative facial palsy in benign parotid tumors, as well as its risk factors, pathology, and clinical results.

STUDY DESIGN

Retrospective analysis.

METHODS

We performed a retrospective analysis of data from patients whose initial operation for a benign parotid tumor had been performed in our department between 1999 and 2020.

RESULTS

We included 1,018 patients in this study. The most common tumor observed was pleomorphic adenoma (614 patients), followed by Warthin tumor (234 patients). Fine-needle aspiration cytology and frozen section biopsy were used to identify the tumor histopathology. The overall rate of postoperative facial nerve palsy was 19.5%; the rate was significantly higher in patients with large-diameter tumors or deep lobe tumors. Postoperative facial palsy improved within 24 months of surgery in all cases. There were no cases with permanent facial palsy.

CONCLUSIONS

Postoperative facial nerve palsy developed regularly after surgery to remove benign parotid tumors despite preservation of the nerve. Palsy rate was high in patients with large tumors or deep lobe tumors. Despite the high risk of facial palsy in these patients and the benign nature of the tumor, we recommend surgery rather than follow-up observation, as the risk of postoperative facial palsy may increase as the tumor grows. It is important to provide an accurate explanation on the risks of postoperative complications to all patients to obtain appropriate informed consent for surgery.

LEVEL OF EVIDENCE

4 Laryngoscope, 2021.

Machine Learning Models for Predicting Facial Nerve Palsy in Parotid Gland Surgery for Benign Tumors

BACKGROUND

Despite the increasing use of intraoperative facial nerve monitoring during parotid gland surgery (PGS) and the improvement in the preoperative radiological assessment, facial nerve injury (FNI) remains the most severe complication after PGS. Until now, no studies have been published regarding the application of machine learning (ML) for predicting FNI after PGS. We hypothesize that ML would improve the prediction of patients at risk.

METHODS

Patients who underwent PGS for benign tumors between June 2010 and June 2019 were included.

RESULTS

Regarding prediction accuracy and performance of each ML algorithm, the K-nearest neighbor and the random forest achieved the highest sensitivity, specificity, positive predictive value, negative predictive value F-score, receiver operating characteristic (ROC)-area under the ROC curve, and accuracy globally. The K-nearest neighbor algorithm achieved performance values above 0.9 for specificity, negative predictive value, F-score and ROC-area under the ROC curve, and the highest sensitivity and positive predictive value.

CONCLUSIONS

This study demonstrates that ML prediction models can provide evidence-based predictions about the risk of FNI to otolaryngologists and patients. It is hoped that such algorithms, which use clinical, radiological, histological, and cytological information, can improve the information given to patients before surgery so that they can be better informed of any potential complications.

Artificial Neural Network as a Tool to Predict Facial Nerve Palsy in Parotid Gland Surgery for Benign Tumors

(1) Background: Despite the increasing use of intraoperative facial nerve monitoring during parotid gland surgery or the improvement in the preoperative radiological assessment, facial nerve injury (FNI) continues to be the most feared complication; (2) Methods: patients who underwent parotid gland surgery for benign tumors between June 2010 and June 2019 were included in this study aiming to make a proof of concept about the reliability of an artificial neural networks (AAN) algorithm for prediction of FNI and compared with a multivariate linear regression (MLR); (3) Results: Concerning prediction accuracy and performance, the ANN achieved the highest sensitivity (86.53% vs 46.23%), specificity (95.67% vs 92.59%), PPV (87.28% vs 66.94%), NPV (95.68% vs 83.37%), ROC–AUC (0.960 vs 0.769) and accuracy (93.42 vs 80.42) than MLR; and (4) Conclusions: ANN prediction models can be useful for otolaryngologists—head and neck surgeons—and patients to provide evidence-based predictions about the risk of FNI. As an advantage, the possibility to develop a calculator using clinical, radiological and histological or cytological information can improve our ability to generate patients counselling before surgery.

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.

Comparison of postoperative complications and facial nerve recovery rates after conventional and partial superficial parotidectomy of benign parotid tumours: a prospective study

The aim of this study was to compare postoperative complications and facial nerve (FN) recovery rates between conventional superficial parotidectomy (CSP) and partial superficial parotidectomy (PSP) as surgical treatment for benign parotid tumours. A prospective study was conducted on 55 consecutive patients who underwent either CSP (n=35) or PSP (n=20) for benign parotid tumours. The primary outcomes were FN injury, FN recovery rates, and Frey syndrome. Secondary outcomes were operative time, hospital stay, sialocele, haematoma, and auricular numbness. The degree of FN injury was evaluated at 1 week, 1, 3, 6, and 12 months postoperative using the House-Brackmann grading system. Frey syndrome was assessed using a subjective clinical questionnaire and objective Minor starch-iodine test. No patient in either group experienced permanent FN paralysis. There was a significantly higher incidence of temporary FN weakness in the CSP group (P=0.007). The respective FN recovery rates at 1, 3, 6, and 12 months were 60%, 88.6%, 94.3%, and 100% in the CSP group and 90%, 95%, 100%, and 100% in the PSP group. No significant difference was observed between the groups regarding the incidence of Frey syndrome, sialocele, and haematoma. The operative time and hospital stay were both shorter in the PSP group. Although the PSP is a more conservative procedure with significantly reduced FN injury, operative time, and hospital stay compared to CSP, the CSP procedure shows a comparable FN recovery rate to the PSP.

Incidence of postoperative facial weakness in parotid tumor surgery: a tumor subsite analysis of 794 parotidectomies

Background

The reported incidence of facial weakness immediately after parotid tumor surgery ranges from 14 to 65%. The purpose of this study was to evaluate the incidence of postoperative facial weakness related to parotidectomy with use of preoperative computed tomography (CT), intraoperative facial nerve monitoring, and surgical magnification. Also, we sought to elucidate additional information about risk factors for postoperative facial weakness in parotid tumor surgery, particularly focusing on the tumor subsites.

Methods

We retrospectively reviewed 794 cases with parotidectomy for benign and malignant tumors arising from the parotid gland (2009–2016). Patients with pretreatment facial palsy were excluded from the analyses. Tumor subsites were stratified based on their anatomical relations to the facial nerve as superficial, deep, or both. Multivariable logistic regression analyses were conducted to identify risk factors for postoperative facial weakness.

Results

The overall incidences of temporary and permanent (more than 6 months) facial weakness were 9.2 and 5.2% in our series utilizing preoperative CT, intraoperative facial nerve monitoring, and surgical magnification. Multivariable analysis revealed that old age, malignancy, and recurrent tumors (revision surgery) were common independent risk factors for both temporary and permanent postoperative facial weakness. In addition, tumor subsite (tumors involving superficial and deep lobe) was associated with postoperative facial weakness, but not tumor size. Extent of surgery was strongly correlated with tumor pathology (malignant tumors) and tumor subsite (tumors involving deep lobe).

Conclusion

Aside from risk factors for facial weakness in parotid tumor surgery such as old age, malignant, or recurrent tumors, the location of tumors was found to be related to postoperative facial weakness. This study result may provide background data in a future prospective study and up-to-date information for patient counseling.

Comparative outcomes of extracapsular dissection and superficial parotidectomy

Background: Retrospective analysis of extracapsular dissection (ECD) and superficial parotidectomy (SP).Aims/objectives: Comparing the outcomes of ECD and SP in surgery of benign parotid masses.Material and methods: Total of 136 patients included in the study. The inclusion criteria were pathologically proven benign FNA biopsy, lack of deep lobe invasion and single tumour diameter lower than 4 cm, absence of radiologically and clinically malignant lesion and facial paralysis at the time of diagnosis.Objectives: Drain volumes and seroma presence, clinical evaluation of face nerve function; signs of infective complications were collected from patients' clinic chart. Complications and recurrence rates were obtained from follow-up forms.Results: The mean follow-up period was 42.53 ± 14.88 months. In SP group, three patients with disease recurrence were found, 8 (10.2%) had early facial nerve paralysis (grade 2 and 3) and 11 (14.1%) had Frey's syndrome. No postoperative complication, early facial paralysis and recurrence were observed in ECD group.Conclusion and significance: ECD procedure was found to be as successful as SP in the selected patient group in approach to the pathologically proven and single benign parotid masses with similar recurrence and lower complication rates compared to the SP.

Displacement of the Facial Nerve by Deep Parotid Lobe Lesions in the Pediatric Population

Objectives

To describe and investigate facial nerve displacement in deep lobe parotid lesions in children and to determine clinical and radiographic predictors of abnormal facial nerve position.

Methods

Retrospective case review of children who underwent total parotidectomy for deep lobe parotid lesions at a tertiary care center between January 2014 and December 2017. Aberrant facial nerve trajectory was defined as ascension of the nerve at an angle of 45° or greater. Elongation was defined as the main trunk >2 cm in length. Patient demographics, radiographic, pathologic results, postoperative nerve weakness, and intraoperative nerve findings were collected. Wilcoxon rank‐sum test and Fisher's exact test were used to assess the associations between variables of interest and facial nerve position.

Results

A total of 20 patients were included. The mean age was 7.7 ± 5 years. The most common pathologies were lymphatic malformation, pleomorphic adenoma, and first branchial cleft cyst. Twelve out of twenty (60.0%) patients had abnormal intraoperative facial nerve position. There was no significant difference in distribution of pathologies between those with or without an abnormal intraoperative nerve position (P = .41). Neither radiographic lesion size nor distance between the lesion and proximal portion of the facial nerve (mastoid tip) were associated with abnormal facial nerve position intraoperatively.

Conclusion

Pediatric deep lobe parotid lesions can displace the facial nerve and distort its anatomy in a posterior lateral direction, in approximately 60% of patients. Statistical analysis of increased numbers of patients to further define predictors of aberrant nerve course is warranted.

Level of Evidence

4.

Complications of traditional and modern therapeutic salivary approaches

The morbidity following traditional surgery of the salivary glands is well documented and includes postsurgical complications such as the Frey's syndrome, complete or partial facial nerve damage, facial scarring, greater auricular nerve numbness, sialocoeles and salivary fistula. The avulsion of the salivary duct, secondary strictures, gland swelling, salivary fistulas and perforations (false rout), traumatic ranulas, and the lingual nerve paraesthesia are the main endoscopy-related complications. In general, the rate of postsurgical complications after modern advanced minimally invasive surgical interventions is significantly lower compared with traditional surgery of the salivary glands. However, such comparisons cannot be performed because up-to-date traditional and minimally invasive surgical techniques are applied to different salivary disorders. Combinations of various minimally invasive techniques are also possible. There is no clear borderline between "traditional" and "modern" surgery of the salivary glands. It is appropriate to write about gradual replacement of old techniques with newer ones, and this process has no traffic lights.

The extent of surgery for benign parotid pathology and its influence on complications: A prospective cohort analysis

BACKGROUND

The surgical management of benign parotid tumors is aimed at complete extirpation of the mass with preservation of facial nerve function. There is a relative paucity of literature pertaining to complications after benign parotid surgery and related risk factors. We aim to critically review the outcomes following treatment of benign parotid pathology when surgery entailed either complete superficial parotidectomy (CSP), partial superficial parotidectomy (PSP) or extracapsular dissection (ECD).

MATERIAL AND METHODS

This is a review of prospectively collected data of all parotidectomies performed between June 2006 to June 2016 for histologically-proven benign pathology of the parotid. Median follow-up time was 31.6weeks.

RESULTS

A total of 101 parotidectomies were carried out on 97 patients (40 CSP, 56 PSP and 5 ECD). Pleomorphic adenoma (48.4%) and Warthin's tumors (32.7%) were the most common pathologies. Temporary facial weakness occurred after 7 operations (6.9%). Facial weakness was permanent in 4 cases (3.9%). The rates of sialocele and salivary fistula were 4.9% and 0.9%, respectively. Only one patient (0.9%) developed Frey Syndrome postoperatively. No significant associations between extent of parotid surgery and postoperative facial nerve dysfunction (p=0.674) or wound complications (p=0.433) were observed. Univariate analyses for potential contributing factors such as advanced age, smoking status, tumor location or histology did not demonstrate any increased risk with developing postoperative complications.

CONCLUSION

Partial superficial parotidectomy was associated with low rates of morbidity to the facial nerve and surgical wound. The results were comparable to complete superficial parotidectomy. We recommend offering patient partial superficial parotidectomy where appropriate and this is in line with the current trend of minimising surgical dissection, thereby potentially decreasing the risk of short-term and long-term complications.

Selective deep lobe parotid surgery for benign tumors

CONCLUSIONS

Deep-lobe tumor parotidectomy decreases the incidence of parotidectomy post-surgical complications, preserves parotid function, and has a good esthetic appearance.

OBJECTIVE

The existing surgical technique in the parotidectomy of deep-lobe benign tumors can be improved.

METHODS

Fourteen surgical operations were performed (2004-2015) for selective deep lobe parotidectomy for patients with primary benign parotid tumors. The patients with deep-lobe benign tumors were operated on with the method of superficial lobe preservation, which included methylene blue staining of the gland and intra-operative facial nerve detection.

RESULTS

During follow-up, no cases of tumor recurrence, permanent facial nerve injury, postparotidectomy depression, or Frey's syndrome was found.

Neurovascular structures of the mandibular angle and condyle: a comprehensive anatomical review

BACKGROUND

Various surgical interventions including esthetic surgery, salivary gland excision, and open reduction of fracture have been performed in the area around the mandibular angle and condyle. This study aimed to comprehensively review the anatomy of the neurovascular structures on the angle and condyle with recent anatomic and clinical research.

METHODS AND RESULTS

We provide detailed information about the branching and distributing patterns of the neurovascular structures at the mandibular angle and condyle, with reported data of measurements and proportions from previous anatomical and clinical research. Our report should serve to help practitioners gain a better understanding of the area in order or reduce potential complications during local procedures. Reckless manipulation during mandibular angle reduction could mutilate arterial branches, not only from the facial artery, but also from the external carotid artery. The transverse facial artery and superficial temporal artery could be damaged during approach and incision in the condylar area. The marginal mandibular branch of the facial nerve can be easily damaged during submandibular gland excision or facial rejuvenation treatment. The main trunk of the facial nerve and its upper and lower distinct divisions have been damaged during parotidectomy, rhytidectomy, and open reductions of condylar fractures.

CONCLUSION

By revisiting the information in the present study, surgeons will be able to more accurately prevent procedure-related complications, such as iatrogenic vascular accidents on the mandibular angle and condyle, complete and partial facial palsy, gustatory sweating (Frey syndrome), and traumatic neuroma after parotidectomy.