Investigation of Parotid Cancer Cases Diagnosed as Bell's Palsy at Initial Presentation: The 23 Year Experience of a Single Institution.

Objective: Facial nerve paralysis due to parotid carcinoma is sometimes misdiagnosed as Bell's palsy. This study aimed to compare patients with parotid carcinoma with and without accompanying facial nerve paralysis and to capture the features of patients misdiagnosed with Bell's palsy. Methods: Among 209 patients, 42 (20%) had facial nerve paralysis. Of these 42 patients, 14 had received treatment for facial nerve paralysis without being diagnosed with parotid carcinoma (pretreatment group); the remaining 28 patients had not received any pretreatment and were diagnosed with parotid carcinoma at the initial visit to our hospital (no pretreatment group). This study compared patients with and without facial nerve paralysis and the pretreatment and no pretreatment groups. Results: The 42 patients with facial nerve paralysis had a significantly higher frequency of pain/tenderness and adhesion with surrounding tissues, significantly higher proportions of deep lobe tumors, and a significantly higher proportion of high-grade malignancy. In addition, the disease-specific and disease-free 5 year survival rates were significantly poorer in patients with than in those without facial nerve paralysis. The comparison between the pretreatment and no pretreatment groups revealed no significant differences in any factors nor survival rate. Five patients in the pretreatment group complained of palpable masses or pain/tenderness at the time of their initial treatment for paralysis. Conclusion: Patients with parotid carcinoma who present with facial nerve paralysis at the initial visit have a significantly poorer prognosis. The number of cases in the pretreatment group can be reduced by performing a detailed examination, which can potentially improve the prognosis.

Prognostic value of electroneurography using the midline method for predicting the development of synkinesis after peripheral facial palsy.

OBJECTIVE: The prognostic value of electroneurography (ENoG) for predicting the incidence of synkinesis is reportedly about 40 % using the formal standard method (ENoG-SM). However, the prognostic value of ENoG using the newly developed midline method (ENoG-MM) has not been determined. The aim of this study was to demonstrate the optimal prognostic value and advantages of ENoG-MM for predicting the incidence of synkinesis. METHODS: Participants were 573 patients treated for peripheral facial palsy including Bell's palsy or Ramsay Hunt syndrome. We investigated the clinical presence of any oral-ocular or ocular-oral synkinesis from the medical records. ENoG-MM and ENoG-SM were performed 10-14 days after symptom onset. In ENoG-MM, compound muscle action potentials were recorded by placing the anode on the mental protuberance and the cathode on the philtrum. In ENoG-SM, electrodes were placed on the nasolabial fold. Synkinesis was clinically assessed at the end of follow-up or at >1 year after onset. The sensitivity and specificity of ENoG values for predicting the incidence of synkinesis were compared between ENoG-MM and ENoG-SM at every 5 % around 40 % (range, 30-50 %). RESULTS: At every 5 % of ENoG values around 40 %, ENoG-MM provided higher sensitivity and lower specificity for predicting the incidence of synkinesis compared with ENoG-SM. In particular, when the cut-off value was set at 45 %, sensitivity was 100 % and 95.3 % with ENoG-MM and ENoG-SM, respectively. CONCLUSION: In peripheral facial palsy, ENoG-MM offered higher sensitivity than ENoG-SM for predicting synkinesis. ENoG-MM is useful for screening patients at risk of developing synkinesis. In clinical practice, an ENoG-MM cut-off value of 45 % must be the optimal prognostic value because of the 100 % sensitivity.

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.

Evaluation of Vestibular Functions in a Case of Vestibular Migraine With Successful Treatment With Erenumab.

This is the first report of vestibular examinations before and after the successful treatment of vestibular migraine (VM), a common cause of recurrent vertigo, with calcitonin gene-related peptide (CGRP) receptor inhibitor. We evaluated a 42-year-old female with VM and concomitant probable Meniere's disease, whose headache and dizziness have improved promptly with the administration of erenumab, a CGRP receptor inhibitor. The sensorineural hearing loss in pure-tone audiometry, dysfunctions shown in vestibular examinations (cervical and ocular vestibular evoked myogenic potentials), and mild endolymphatic hydrops shown in gadolinium-enhanced inner ear magnetic resonance imaging, all in the right ear, revealed no change compared with those observed before treatment. This case suggests that VM may be treated by blocking CGRP in the trigeminal ganglion, which suppresses the effects on the vestibular nucleus; herein, no effects were observed in the inner ear despite the clear amelioration of dizziness.

Management and outcome of adenoid cystic carcinoma of the major salivary glands: the 22-year experience of a single institution.

BACKGROUND: Prognostic factors and survival rate are difficult to determine for adenoid cystic carcinoma(AdCC) of salivary glands. AIMS/OBJECTIVES: To clarify the clinical characteristics of AdCC and examine factors associated with recurrence and prognosis by histopathological grade classification. MATERIALS AND METHODS: Twenty-five patients with AdCC of the parotid gland and 10 patients with AdCC of the submandibular gland were included. We classified AdCC histopathologically by the proportion of solid components. Clinical features, fine-needle aspiration cytology (FNAC), and patient outcomes were examined according to grade. Factors associated with local recurrence and distant metastases were examined. RESULTS: Age was significantly higher in the grade III group than in the grade I group. The grade III group had significantly higher proportions of patients with cN+, pN+, and perineural invasion. In FNAC, lower-grade groups showed higher rates of correct histopathological type. Five-year disease-specific survival and disease-free survival rates were significantly lower in the grade III than in the grade I. Distant metastases were more common among patients with high-stage and perineural invasion. CONCLUSIONS: Five-year survival is significantly worse in patients with grade III.

Saccular functions differ for Meniere's disease with and without coexisting headaches.

Objectives: To elucidate the differences between the cases of Meniere's disease (MD) with and without coexisting headaches, especially migraine. The clinical characteristics and vestibular functions are compared. Subjects: Fifteen patients with definite unilateral MD without headaches (MD/H-; 10 males and 5 females; mean age of 55.8 years), and 20 patients with definite unilateral MD with headaches (MD/H+; 3 males and 17 females; mean age of 54.4 years; 15 cases of migraine without aura and 5 cases of suspected migraine or tension-type headache) were enrolled. Methods: The medical records, caloric test results, and cervical vestibular evoked myogenic potential (cVEMP) of the patients were reviewed. A monothermal caloric test by injection of cold water was performed, and canal paresis was assessed. cVEMP was recorded using 500 Hz short tone bursts, and the asymmetry ratio using the corrected amplitude of p13-n23 was determined. Results: The patients in the MD/H- group were predominantly male, whereas more female patients were seen in MD/H+ group (p = 0.004). In the MD/H+ group, the frequency of vertigo and the dizziness handicap inventory (DHI) values were significantly higher than those in the MD/H- group (p = 0.045, <0.001, respectively). There was no statistical difference in the ages, duration of illness, or the hearing levels between both groups. The caloric testing results were abnormal for 10 of the 13 MD/H- cases, and 14 of the 16 MD/H+ cases, which revealed no significant difference between both groups. The cVEMP results revealed positive saccular dysfunction based on the asymmetry ratio of 4 of the 15 MD/H- cases, and 14 of the 20 MD/H+ cases; it was significantly more prevalent in the MD/H+ group than in the MD/H- group (p = 0.018). Multivariate analysis of sex, frequency of vertigo, DHI, and cVEMP results showed significant differences only in the cVEMP results (p = 0.049). Conclusion: The present study revealed differences in patients with MD depending on the presence or absence of headaches. MD without headaches showed a significant male preponderance. MD with coexisting headaches was more associated with severe saccular dysfunctions than MD without headaches. Concomitant headache may affect the manifestations of the vestibular function, especially in the sacculus, in MD cases.

Proposal for a novel classification of benign parotid tumors based on localization.

OBJECTIVE: Postoperative facial nerve paralysis is the most problematic complication after surgical treatment of parotid tumors. Localization of tumors is highly relevant for the surgical approach, but existing classification systems do not focus on the association between localization and surgical technique. Therefore, we created a new localization-based classification system for benign parotid tumors and investigated the characteristics of tumors in each localization and the frequency of postoperative facial nerve paralysis by retrospectively applying the classification to previous cases. METHODS: First, we defined 6 portions of the parotid gland (upper, U; lower, L; posterior, P; anterior, A; superficial, S; deep, D) by dividing the transverse plane into an upper and lower portion at the mandibular marginal branch, the longitudinal plane into a posterior and anterior portion at the midline of the parotid anteroposterior diameter, and the sagittal plane into a superficial and deep portion along the course of the facial nerve. Then, we defined 8 locations by combining the 6 portions in all possible ways (i.e., U-P-S, U-P-D, U-A-S, U-A-D, L-P-S, L-P-D, L-A-S, L-A-D). We used this classification to define the tumor localization in 948 patients who had undergone partial superficial parotidectomy for benign parotid tumors and then investigated the incidence, histopathological type, signs/symptoms, diagnosis, surgery, and complications in each area. RESULTS: Pleomorphic adenomas comprised approximately 70% of tumors in the upper portion but only approximately 35% in the lower portion. The rate of postoperative facial nerve paralysis was significantly higher for tumors in deep locations than in superficial locations (33.9% vs 14.9%, respectively), and the odds ratios for postoperative facial nerve paralysis in the U-P-D and U-A-D locations were 7.6 and 4.8 compared to the L-P-S location. When maximum diameter, operation time, bleeding volume, sex (reference: female), and age were added as control variables, the odds ratios were 4.2 and 3.0. CONCLUSION: Determining tumor localization preoperatively with the new localization-based classification of parotid tumors is helpful not only for predicting the histopathological type but also for predicting surgical complications, particularly postoperative facial nerve paralysis.

Recurrent facial palsy: Characteristics of ipsilateral and alternative palsies of 104 cases.

OBJECTIVE: Recurrent facial palsy is relatively rare and its clinical details of recurrent facial palsy are not well known. We analyzed recurrent facial palsy cases and clarified its characteristics, especially the difference between ipsilateral and alternative palsies. The analysis aimed to obtain information about recurrent facial palsy that would be useful for delivering explanations to patients and help improve recurrent facial palsy treatments based on the etiology. METHODS: We picked up data from the chart and analyzed the clinical characteristics of patients with recurrent facial palsy from 1243 facial palsy patients (Bell's palsy, VZV-related palsy (Ramsay Hunt syndrome and zoster sine herpete [ZSH])) between 2006 and 2020. RESULTS: Recurrent facial palsy was observed in 104 of 1243 patients (8.4%). There were 35 cases (34%) of ipsilateral palsy and 69 cases (66%) of alternative palsy. The mean age at the onset of the first palsy was 38.9 years old in the ipsilateral group and 48.4 years old in the alternative group, and a significant difference was observed between them. The number of recurrences ranged from 1 to 4. Among the ipsilateral group, 6 patients experienced more than second recurrence. In two cases, the condition failed to resolve after the second recurrence. A serological examination confirmed that 4 cases had recurrent VZV-related palsy (both the first and second palsies were VZV-related) and all of them initially had ZSH: no cases had Hunt syndrome as the first palsy. CONCLUSIONS: The VZV-specific immunity obtained with ZSH might be insufficient to suppress VZV reactivation, and VZV vaccination should be recommended for ZSH patients to prevent further recurrence of VZV-related facial palsy. More than 2 ipsilateral recurrent episodes may be a risk factor for incomplete recovery.

An electrophysiological prognostic diagnosis for facial palsy.

Two electrophysiological tests for facial palsy-electroneurography (ENoG) and nerve excitability test (NET)-were reviewed. ENoG has advantages over NET in that it reflects the percentage of degenerated facial nerve fibers and can provide an accurate prognosis. However, as disadvantages, ENoG requires large, expensive equipment, and such supramaximal electrical stimulation can be quite painful for patients. NET is less painful due to weak stimulation with just enough current to meet the threshold, and the required equipment is compact and inexpensive to procure. However, it is impossible to calculate the percentage of degenerated nerve fibers, and NET is inferior to ENoG in terms of accurate prognostic prediction for facial palsy. The appropriate timing for both ENoG and NET is 7 to 10 days after the onset. While ENoG has proven more popular than NET because of its accuracy for prognostic prediction, we should not predict the prognosis of facial palsy based solely on the results of electrophyisiolgical examinations; a comprehensive evaluation including the facial muscle grading system is essential.

Development of the Sphenoid Sinus in Japanese Children: A Retrospective Longitudinal Study Using Three-Dimensional Computed Tomography.

Background: The sphenoid sinus (SS) is located close to vital structures, such as the pituitary gland, and it has significant clinical relevance. This study aimed to clarify the growth pattern of the SS in Japanese children using three-dimensional computed tomography (CT). Methods: Seventy-eight participants with congenital, acquired, or external auditory canal cholesteatoma were recruited and underwent CT more than twice during their treatment. Using the volume-rendered images, the size and volume of the SS were measured. Furthermore, on the scout image, the morphological measurements of the cranial base were determined. Results: The size and volume of the SS increased with age, and peaked at the mean age of 15 years. For males, the volume of the SS was smaller than that of females aged <5 years. The growth rate of the SS was significantly higher in males than in females. The maximum growth rate was detected at the age of 12 years for males and 10 years for females. For females, the increase in the length of the anterior cranial base ceased at approximately 10 years of age and remained constant thereafter. In contrast, for males, the length of the anterior cranial base increased gradually until 15 years of age. Conclusions: Considering the similarity of the periods between the adolescent growth spurt and the maximum growth rate of the SS, changes in the size of the SS may be used as an indicator of the physical growth spurt.

Different results of vestibular examinations and blood flow in cases with transient vascular vertigo/dizziness with or without central nervous system symptoms.

BACKGROUND: The condition of vestibular dysfunction and blood flow in the vertebral artery (VA) in transient vascular vertigo/dizziness (TVV) is not well established. OBJECTIVES: To clarify the pathophysiology of TVV, especially the difference between the isolation of vestibular symptoms. MATERIALS AND METHODS: Ten TVV patients with central nervous system symptoms (TVVw) and 12 TVV patients without central nervous system symptoms (TVVo) underwent duplex color-coded ultrasonographic evaluation of VAs, caloric test, and cervical vestibular-evoked myogenic potential (cVEMP). RESULTS: The mean flow velocity (MV) ratio (peak MV of contralateral VA divided by target VA) was significantly higher in TVVw than in TVVo. There was no difference in the occurrence of canal paresis between TVVw and TVVo. Abnormal asymmetry ratios (ARs) of cVEMP were observed only in TVVo cases (6 of 12 cases), revealing a statistically significant difference in the number of cases between TVVw and TVVo. CONCLUSIONS AND SIGNIFICANCE: Measuring VAs using duplex color-coded ultrasonography and cVEMP may help evaluate TVV. Different results of MV ratio and cVEMP between TVV cases with or without central nervous system symptoms may indicate differences in the pathophysiology between TVVw and TVVo.

Management for Warthin Tumor of the Parotid Gland: Surgery or Observation. A 21-Year Retrospective Study of 387 Cases.

PURPOSE: This study investigated the characteristics, diagnosis, and treatment of Warthin tumors (WTs) to explore the possibility of managing patients by observation. METHODS: We reviewed the records of 1167 patients with benign parotid tumors who were seen in our department between September 1999 and April 2021. Among them, 387 cases were WT and 668 cases were pleomorphic adenoma. We evaluated preoperative diagnoses of WT by symptoms/signs, fine-needle aspiration cytology (FNAC), imaging, such as ultrasonography and magnetic resonance imaging, and technetium-99m pertechnetate (Tc-99m) scintigraphy. Fisher's exact test and the Mann-Whitney U test were used in statistical analyses. RESULTS: Warthin tumors were treated by surgery in 238 cases and follow-up in 149 cases. The 238 patients were diagnosed as WT at the final pathology after surgery. Among them, 172 patients (72.3%) were determined as benign histological type by preoperative FNAC; in these 172 patients, 170 (71.4%) were correctly diagnosed as WT in the final pathology. Preoperative Tc-99m scintigraphy was performed in 69 patients diagnosed with WT by final pathology or FNAC, and the positive rate of Tc-99m scintigraphy in WT was 75.4%. CONCLUSIONS: Combining FNAC and Tc-99m scintigraphy, as well as considering clinical findings, enables the diagnosis of WT in most cases. In particular, WT is more common in the elderly, grows more slowly, and is less likely to be malignant. Therefore, if WT can be diagnosed preoperatively with a high rate of correct diagnosis, it could be an accurate and effective means of managing patients through follow-up without surgery.

Facial Nerve Palsy in a Young Patient With Acute Lymphoblastic Leukemia Possibly Induced by Herpes Virus Reactivation in the Facial Nerve.

Facial palsy in acute lymphoblastic leukemia (ALL) patients is diagnosed as tumor cell invasion of the central nervous system (CNS) following the ALL guidelines. Facial palsy in a 6-year-old ALL patient was diagnosed as leukemia cell invasion into the CNS by hemato-oncologists. Pretreatment magnetic resonance image (MRI) revealed gadolinium enhancement of the first genu and meatal portion of the facial nerve. After chemotherapy, although the ALL tumor cells disappeared from both the blood and the cerebrospinal fluid, and the facial palsy resolved, a posttreatment MRI showed no change in terms of enhancement of the facial nerve. These findings indicated the possibility of herpetic viral reactivation in the geniculate ganglion of the facial nerve. We must be aware and discuss with hemato-oncologists the possibility that not only tumor cell invasion into the CNS, in accordance with the guidelines, but also that herpetic virus reactivation arising in the facial nerve may be causes of facial palsy.

Asymmetry and tuning shift of the cervical vestibular evoked myogenic potential indicate saccular dysfunction in idiopathic normal pressure hydrocephalus.

OBJECTIVE: The purpose of this study was to investigate the effects of excessive cerebrospinal fluid (CSF) retention on the peripheral vestibular function and the inner ear fluid in patients with idiopathic normal pressure hydrocephalus (iNPH). METHODS: In 25 patients with iNPH (14 females, age 65-88 years), cervical vestibular evoked myogenic potential (cVEMP) was measured before the spinal tap test. The asymmetry ratios (ARs) and tuning properties in 500 Hz and 1,000 Hz short-tone burst stimuli of cVEMP were evaluated. Furthermore, cVEMP was measured in an age-matched control group of 12 non-iNPH patients. RESULTS: Seven (28%) iNPH patients exhibited a cVEMP asymmetry (AR > 33%). cVEMP tuning was significantly shifted to a higher frequency in the iNPH group than in the age-matched control group. CONCLUSIONS: One-fourth of patients with iNPH had obvious saccular dysfunction. A high rate of a shift in cVEMP tuning in the iNPH group indicated that excessive CSF accumulation propagated to the endolymph and perilymph. SIGNIFICANCE: Saccular dysfunction might be one of the possible causes of imbalance in iNPH, and the shift in cVEMP tuning may be a determining factor in the diagnosis and treatment strategy.

Characteristics and Outcomes of Parotid Gland Tumors in Adolescents.

OBJECTIVE: Parotid tumors are rare neoplasms in adults but are exceedingly infrequent in adolescents. We aimed to determine the clinical characteristics and outcomes of parotid tumors in adolescents under 20 years old. METHODS: Between 1999 and 2020, 979 cases of benign parotid tumors and 236 cases of malignant parotid tumors were treated surgically in our department. Of these, 12 benign cases (1.2%) and 9 malignant cases (3.8%) were in adolescents. There were no benign or malignant cases for those aged under 10 years. RESULTS: Regarding the histological type, all benign tumors were pleomorphic adenomas. About half of malignant tumors were mucoepidermoid carcinomas, and excluding one high-grade case, the grade of malignancy was all low/intermediate. The accuracy of fine-needle aspiration cytology among adolescents showed no significant difference with that of adults. In contrast to adults, adolescent benign tumor cases showed a markedly high rate of pleomorphic adenomas and no postoperative facial nerve palsy. Malignant tumors in adolescents had a different trend than adults; low/intermediate-grade malignancies were common and thus few symptoms/signs of malignancy could be observed. As well, the accuracy of fine-needle aspiration cytology was poor. All cases had a good prognosis and are disease-free survival. CONCLUSION: Parotid tumors in adolescents are rare but have several characteristics that are distinct from adults. As long-term observation is required posttreatment in adolescent patients, recurrence in benign pleomorphic adenomas and poor long-term prognosis in malignant tumors, especially for those with low/intermediate-grade malignancy, are more likely to be observed.

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, 131:E2857-E2864, 2021.

Symptoms and signs of parotid tumors and their value for diagnosis and prognosis: a 20-year review at a single institution.

BACKGROUND: Detailed clinical features other than parotid mass have not been investigated in detail for parotid tumors. Symptoms and signs are useful for the differentiation of benign versus malignant, and may also be of value to determine the grade of malignancy and histological type as well as the assessment of prognosis. METHODS: We reviewed symptoms and signs of 965 patients with benign tumors and 200 patients with malignant tumors. Symptoms and signs included pain/tenderness, adhesion to surrounding tissues, and facial nerve palsy. We reviewed the incidence in benign and malignant tumors, in histological type of benign tumors, and in grade and histology of malignant tumors. For each symptom or sign, covariates were analyzed, and their correlation with the prognosis was investigated. RESULTS: The incidence of symptoms and signs was significantly higher in malignant than benign tumors, and more frequent in higher grade of malignancy. Facial nerve palsy was observed in 18.0% of malignant tumor cases, while none occurred in benign tumor cases. Pain/tenderness was more commonly observed in adenoid cystic carcinoma, while adhesion to surrounding tissues and facial nerve palsy were most frequently noted in salivary duct carcinoma. The prognosis of patients with these symptoms and signs was significantly poor. CONCLUSION: A detailed investigation of symptoms and signs in parotid gland tumors is the first step that leads to the diagnosis of malignant tumors. Symptoms and signs are also useful for estimating the grade of malignancy and histological type, and they are important information for predicting prognosis.

Effective surgical management of anterior tumors of the parotid gland: Main trunk method vs. peripheral Smethod.

OBJECTIVE: Several surgical procedures have been proposed for tumors in the anterior parotid gland. Although the standard approach to other parotid tumors is generally also used for anterior tumors, handling of the facial nerve has not been addressed in any previous reports. METHODS: A total of 654 patients with benign parotid tumors who underwent surgery in our department were classified into anterior (AT), middle (MT), and posterior tumor (PT) groups according to tumor location. Clinical characteristics, histopathological types, and frequency of postoperative transient facial palsy were examined. In the AT group, two surgical methods were compared, which were the main trunk method (MTM) and the peripheral method (PM). RESULTS: 172 patients were included in the AT group, 175 in the MT group, and 307 in the PT group. The AT group showed significant female predominance and a higher percentage of deep lobe tumors than the PT group. There was no significant difference in the rate of postoperative transient facial palsy among the AT (MTM), MT, and PT groups. The PM had a significantly shorter operating time and lower rate of transient facial palsy than the MTM. CONCLUSION: The PM for AT was considered a useful surgical method from the standpoints of postoperative complications and operating time. In the PM, a wide operating field made identification of the facial nerve easier.

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.