Postoperative Facial Palsy Research Articles

Rationale for the Development of a Novel Clinical Grading Scale for Postoperative Facial Nerve Function: Results of a Multidisciplinary International Working Group.

The objective of the current study was to present the results of an international working group survey identifying perceived limitations of existing facial nerve grading scales to inform the development of a novel grading scale for assessing early postoperative facial paralysis that incorporates regional scoring and is anchored in recovery prognosis and risk of associated complications. Survey. A working group of 48 multidisciplinary clinicians with expertise in skull base, cerebellopontine angle, temporal bone, or parotid gland surgery. House-Brackmann grade is the most widely used system to assess facial nerve function among working group members (81%), although more than half (54%) agreed that the system they currently use does not adequately estimate the risk of associated complications, such as corneal injury, and confidence in interrater and intrarater reliability is generally low. Simplicity was ranked as the most important attribute of a novel postoperative facial nerve grading system to increase the likelihood of adoption, followed by reliability and accuracy. There was widespread consensus (91%) that the eye is the most critical facial region to focus on in the early postoperative setting. Members were invited to submit proposed grading systems in alignment with the objectives of the working group for subsequent validation. From these data, we plan to develop a simple, clinically anchored, and reproducible staging system with regional scoring for assessing early postoperative facial nerve function after surgery of the skull base, cerebellopontine angle, temporal bone, or parotid gland.

Penetrating Offenders in Hemifacial Spasm: Surgical Tactics and Prognosis.

(1) Background: In cases of hemifacial spasm (HFS), there are various patterns related to the vascular compression of the facial nerve, including a very rare form that is seen when the offending vessel penetrates the facial nerve. However, there have been few reports in the literature regarding the associated surgical techniques and postoperative prognosis. (2) Methods: A retrospective review was conducted of 4755 patients who underwent microvascular decompression (MVD) surgery from April 1997 to June 2023. In total, 8 out of the 4755 patients (0.2%) exhibited a penetrating offending vessel; the medical and surgical records of these 8 patients were then analyzed. Surgery was then attempted to maximally decompress the penetrating offender. (3) Results: Seven out of the eight patients (87.5%) were spasm-free immediately after surgery, and one had only 10% residual spasm compared to their preoperative condition. That patient was also spasm-free one year later. Postoperative facial palsy occurred in one patient (12.5%) who was assessed as grade II in the House-Brackmann grading system. In another patient, the resection of a small facial nerve bundle did not result in facial palsy. There were no cases of hearing loss or other complications. (4) Conclusions: Decompressing the penetrating offender did not increase the incidence of facial palsy, and the prognosis for hemifacial spasms was good. Therefore, when a penetrating pattern was encountered during MVD surgery, decompression between the penetrating offender and the facial nerve may offer good results.

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

ObjectiveFacial 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). MethodsParticipants 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. ResultsRates 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. ConclusionPatients 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.

Cerebellopontine angle tumours: clinico-radiological features and surgical outcome

Object. Our aim is to demonstrate the various aspects of clinical-Radiological presentation and surgical Outcome with association to the tumour size concerning cerebellopontine angle (CPA) tumours.
 Materials and method. This is a prospective study of 40 patients at the Department of Neurosurgery, Jayarogya Group of Hospitals, GRMC Gwalior, M.P. India. All of the patients were pre-operatively evaluated with either non-enhanced and enhanced computerized tomography (CT) or Magnetic-resonance (MR) imaging or both.CPA tumours (predominantly acoustic neuroma) that underwent surgical removal using a suboccipital retro sigmoid approach over a 2-year period (June 2019 to May 2021).
 Results. There was a female preponderance. The most common presentation was Sensorineural hearing loss (90%) followed by Headache (67.5%). The majority of cases of Vestibular Schwannoma have heterogenous enhancement with cystic component.65% of patients have large (26-40mm) size tumours and facial nerve preservation is 86.4% in medium size tumours (10-25 mm).and Incidence of post-postoperative of facial nerve palsy is more in Giant size tumour (> 40mm) so Positive association between size of lesion and Incidence of Post-operative facial nerve palsy. CSF leak occurs in 6 patients and postoperative Hydrocephalus occur in 2 patients and Mortality occurs in 3 patients.
 Conclusion. CP angle Tumor was common in middle age group, with the incidence in females slightly more than in males. The majority of lesions were of large size (26-40mm). Most of the patients on admission had a non-serviceable hearing. Heterogeneous enhancement with cystic components was found in most of the lesions. Gross-total excision was one in the majority of cases and vestibular schwannoma was the most common histopathological lesion obtained. Facial nerve palsy was the most complication and as the size of the lesion increased, the possibility of facial nerve palsy also increased post-operatively. Overall mortality is 7.5%.

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

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

889 Significance of Cortico-Bulbar Motor Evoked Potential (CoMEP) Monitoring in Vestibular Schwannoma Surgery for Prediction of Postoperative Facial Nerve Palsy

INTRODUCTION: Direct facial nerve stimulation during vestibular schwannoma surgery (VSS) allows preservation of the nerve in its continuity. However, prognostication of post- operative nerve function remains challinging. METHODS: In total, 51 patients (median age 52yrs; 19-84) with unilateral VS (median size 20mm;10-50) were included. Intraoperative neuromonitoring consisted of auditory evoked potentials (AEPs), direct facial nerve stimulation and CoMEPs. An anodal stimulation via subdermal corkscrew electrodes on position C3 or C4 and a cathode near Cz with a train of 6 pulses, each with a duration ono 500us, at a frequency of 5000 Hz and an interstimulus-interval of 2 ms was used. RESULTS: Complete resection was achieved in >90% of patients. Preoperative hearing was preserved in 78% (40/51) patients and postoperative serviceable hearing was preserved in 35% (18/49) patients and was closely related to preserved wave V of the AEPs. Additionally, MEPs were successfully monitored in every patient for the entire duration of the surgery. In 16% of the patients, more than 50% reduction of MEP baseline amplitude was recorded, correlating directly with moderate to severe postoperative facial palsy (House Brackman 3-5). No facial palsy without MEP amplitude reduction was observed. During 6 months FU, recovery of 1-2 HB Grades was observed in all cases. All patients with intraoperative MEP amplitude reduction had significant larger VS than patients without MEP amplitude reduction (27 vs 22 mm, p = 0.02) CONCLUSIONS: In addition to direct facial nerve stimulation, intraoperative CoMEP monitoring during VSS seems to be of high significance and value for intraoperative facial nerve preservation and prognosis estimation of postoperative short- and long-term facial palsy.

EVALUATION OF THE MICROSURGERY RESULTS FOR ACOUSTIC NEUROMA USING AN INTRAOPERATIVE NERVE MONITORING SYSTEM

Objectives: To evaluate the results of microsurgery for acoustic neuroma using an intraoperative nerve monitoring system. Subjects and methods: Cross-sectional, retrospective, and prospective description of 74 patients with acoustic neuroma who were microsurgically treated in Viet Duc University Hospital from October 2016 to March 2018. Results: Women (58.11%) were more predominant than men (41.89%). The age mean was 50.41% ± 9.43 years. There was no significant difference between the tumor location on the right and left side (54.41 compared to 45.59%). There were 40 patients with large tumors (54.05%), giant tumors in 20 patients (27.02%), and 14 patients (18.92%) with small tumors < 2.5cm. Postoperative magnetic resonance examinations were indicated for 100% of patients, in which 78.37% full of tumors were taken out and 21.63% were taken almost tumors. The rate of intact facial nerve was 93.3%. The damage rate of the facial nerve was about 20.28%. The most complications were cerebral edema, bleeding, hydrocephalus, death and meningitis (5.4%; 4.05%; 4.05%; 2.7%, and 1.35%, respectively). The recovery of the function of the VII nerve, grade I, II according to House-Brackmann was 79.72%. Conclusion: Neurosurgical intervention remains the main step in the effective management of vestibular schwannomas. Using a continuous monitoring system for the facial nerve in surgery for vestibular schwannoma has reduced the rate of post-operative facial nerve paralysis.

A rare case of schwannoma of the mandibular nerve extending to parapharyngeal space managed with a preauricular trans mandibular approach

Schwannoma also referred to as neurilemmoma or neurinomas arise from the Schwann cells of the autonomic nerves, peripheral nerves and cranial nerves except optic and olfactory nerves. Head and neck schwannomas account for 25 to 45% of schwannomas and the most common being vagal schwannomas and cervical sympathetic chain schwannomas. Schwannomas arising from the trigeminal nerve are rare and this case report consists of a schwannoma presenting as a left preauricular swelling involving the region of parotid extending from foramen ovale through the infratemporal fossa up to the parapharyngeal space. A combined preauricular trans mandibular approach enabled a complete excision of the tumor. Histopathological confirmation of a benign schwannoma was obtained and the patient is feeling well with minimal postoperative facial palsy with no trismus, occlusion abnormalities and no signs of recurrence on follow up.

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

ObjectivePostoperative 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. MethodsFirst, 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. ResultsPleomorphic 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. ConclusionDetermining 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.

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

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. 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. 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). 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.

Assessing the Efficacy of Anastomosis between Ansa Cervicalis and Facial Nerve for Patients with Concomitant Facial Palsy and Peripheral Neuropathy.

Background: For decades, patients with facial asymmetry have experienced social interaction difficulties, leading them to seek treatment in the hope of restoring facial symmetry and quality of life. Researchers evaluated numerous surgical techniques, but achieving results remains a significant hurdle. Specifically, anastomosis between the ansa cervicalis (AC) and facial nerve (FN) can hinder the patient's physical appearance. Objective: Our study goal was to examine the efficiency of anastomosis between AC and FN for facial motor function recovery even in the presence of peripheral neuropathy. Materials and Methods: Four patients diagnosed with facial palsy grade VI on the House & Brackmann Scale (HB) after vestibular schwannoma (VS) resection (Koos grade IV) via the retrosigmoid approach underwent AC and FN anastomosis. Outcomes were related to tumor grade, previous therapy, and the time between postoperative facial palsy and anastomosis. Images and neurophysiological data were evaluated. Results: After vs. resection, all four patients demonstrated HB grade VI facial palsy for an average of 17 months. During the follow-up program, lasting between 6 and 36 months, two patients were evaluated as having HB grade III facial palsy; the other two patients were diagnosed with grade IV HB facial palsy. None of the patients developed tongue atrophy, speech disorder, or masticatordys function. Conclusions: Anastomosis between the AC and FN is a safe and effective treatment for facial paralysis after cerebellopontine tumor resection. Nerve reanimation may be feasible even for patients with peripheral polyneuropathy. This study also offers a new option for patients with a progression-free status.

Prospective Assessment of Risk Factors Influencing Facial Nerve Paresis in Patients after Surgery for Parotid Gland Tumors.

Background and objectives: Facial weakness is the most important complication of parotid gland tumor surgery. The aims of this study are as follows: (1) assessment of the prevalence of postparotidectomy facial nerve dysfunction; (2) clinical and electrophysiological assessment of the facial nerve function before parotidectomy and at 1 and 6 months postoperatively; (3) assessment of the association of postoperative facial palsy with selected risk factors; and (4) assessment of the correlation between the results of clinical and neurophysiological assessments of facial nerve function. Materials and Methods: This study comprised 50 patients (aged 24-75 years) who underwent parotidectomy at the Department of Otolaryngology and Laryngological Oncology in Zabrze, Poland between 2015 and 2017. The evaluation included neurological, clinical and electrophysiological assessments of the facial nerve prior to surgery and at 1 and 6 months postoperatively. Results: No facial palsy was found preoperatively or 6 months postoperatively. Facial nerve dysfunction was found in 74% of patients 1 month postoperatively. In most cases (54%), paresis was mild or moderate (House-Brackmann grades II and III). The results of electrophysiological tests before parotidectomy were either normal or showed some mild abnormalities. We found a statistically significant correlation between the clinical assessment of the facial nerve function (based on the House-Brackmann scale) one month postoperatively and the latency of the CMAP response from the orbicularis oculi and orbicularis oris muscles. In all three studies, a statistically significant correlation was found between the amplitude of the compound muscle action potential (CMAP) of the orbicularis oris muscle and the degree of facial nerve weakness. Conclusions: The factors that may influence the risk of postoperative facial nerve paralysis (prolonged surgical time and the size and location of the tumor other than in the superficial lobe only) may indirectly suggest that surgery-related difficulties and/or surgeon experience could be crucial to surgery safety.

Comparative analysis of benign and malignant parotid gland tumors: A retrospective study of 992 patients

ObjectiveWe analyzed and compared the clinical characteristics of benign and malignant parotid gland tumors. Patients and methodsA total of 992 patients who underwent surgical treatment for parotid gland tumors from January 2010 to December 2020 were included in this study. This study population was subdivided into benign (n = 812, 81.9 %) and malignant parotid gland tumors (n = 180, 18.1 %). ResultsPleomorphic adenoma is the most common benign tumor and mucoepidermoid carcinoma is the most common malignant tumor. The patients with malignant parotid gland tumors were older than the patients with benign lesions. The duration of symptoms was longer in patients with benign parotid gland tumors compared to those with malignant lesions. The size of the malignant tumors was larger than that of the benign lesions. Preoperative fine-needle aspiration cytology had a diagnostic sensitivity of 50.3 %, diagnostic specificity of 98.7 %, a positive predictive value of 89.5 %, a negative predictive value of 89.9 %, and accuracy of 89.9 % for diagnosing malignant parotid gland tumors. For benign parotid gland tumors, superficial parotidectomy was most frequently performed, and for malignant parotid gland tumors, total parotidectomy was most frequently performed. Facial palsy was observed in 19.4 % of the patients with malignant parotid gland tumors compared to 5.4 % of those with benign tumors. ConclusionThe clinical features of benign and malignant parotid gland tumors showed differences in age, symptoms, duration of symptoms, size and site of the parotid tumors, surgical procedures, and postoperative facial nerve palsy.

Neural networks for estimation of facial palsy after vestibular schwannoma surgery

PurposeFacial nerve damage in vestibular schwannoma surgery is associated with A-train patterns in free-running EMG, correlating with the degree of postoperative facial palsy. However, anatomy, preoperative functional status, tumor size and occurrence of A-trains clusters, i.e., sudden A-trains in most channels may further contribute. In the presented study, we examine neural networks to estimate postoperative facial function based on such features.MethodsData from 200 consecutive patients were used to train neural feed-forward networks (NN). Estimated and clinical postoperative House and Brackmann (HB) grades were compared. Different input sets were evaluated.ResultsNetworks based on traintime, preoperative HB grade and tumor size achieved good estimation of postoperative HB grades (chi2 = 54.8), compared to using tumor size or mean traintime alone (chi2 = 30.6 and 31.9). Separate intermediate nerve or detection of A-train clusters did not improve performance. Removal of A-train cluster traintime improved results (chi2 = 54.8 vs. 51.3) in patients without separate intermediate nerve.ConclusionNN based on preoperative HB, traintime and tumor size provide good estimations of postoperative HB. The method is amenable to real-time implementation and supports integration of information from different sources. NN could enable multimodal facial nerve monitoring and improve postoperative outcomes.

Does preoperative gamma knife treatment affect the result of microresection of vestibular schwannoma?

We aimed to explore the influence of preoperative gamma knife treatment on the clinical effect of microsurgical resection of vestibular schwannoma. The data of patients who underwent vestibular schwannoma resection in our hospital between November 2010 and December 2019 were retrospectively collected. According to the data collected retrospectively and the inclusion and exclusion criteria, we selected these patients and divided them into Group A (with preoperative gamma knife treatment) and Group B (without preoperative gamma knife treatment). The pre/postoperative clinical manifestations, neurological function grade, postoperative complications, tumor recurrence and increase were collected and compared between the two groups. There were 40 and 823 patients enrolled in Groups A and B, respectively. There were no significant differences in the general condition, tumor size and side, or neurological performance of the patients in those two groups before the operation. At the last follow-up, the number of patients with poor facial nerve function was 15 (39.5%) in Group A and 170 (20.7%) in Group B (P = 0.021 < 0.05). In Group A and Group B, disequilibrium occurred in 14 (36.8%) patients and 124 (15.1%) patients, respectively, after the operation (P = 0.012 < 0.05). Seven (17.5%) patients had pneumonia in Group A, and 21 (2.6%) patients had pneumonia in Group B (P = 0.04 < 0.05) after the operation. When a patient with vestibular schwannoma undergoes microsurgical surgery, the preoperative history with gamma knife treatment may make recovery from postoperative facial paralysis difficult for the patients, making them more prone to suffer from postoperative disequilibrium and postoperative pneumonia.

Intratemporal Facial Nerve Schwannomas: A Review of 45 Cases in A Single Center.

There are no established indications for facial nerve schwannoma treatment, including surgery, radiation and follow-up observation, and it is difficult to determine treatment policy uniformly. The treatment policy was examined from each treatment course. Data of patients with facial nerve schwannomas at our hospital from 1987 to 2018 were retrospectively examined. Their age, sex, clinical symptoms, tumor localization, treatment policies and outcomes were reviewed. In total, 22 patients underwent surgery and 1 patient underwent radiotherapy; 22 patients were followed up without treatment. After total resection, there were no tumor recurrences, and most patients had grade 3 or 4 postoperative facial paralysis. After subtotal resection, tumor regrowth was observed in four patients and reoperation was required in two patients. Facial nerve function was maintained in four patients and was decreased in two patients. During follow-up, six patients showed tumor growth. Only one patient had worsening facial nerve paralysis; four patients underwent facial nerve decompression owing to facial nerve paralysis during follow-up. If the tumor compresses the brain or it is prone to growth, surgery may be indicated, and when the preoperative facial nerve function is grade ≤ 3, consideration should be given to preserving facial nerve function and subtotal resection should be indicated. If the preoperative facial nerve function is grade ≥ 3, total resection with nerve grafting is an option to prevent regrowth. If there is no brain compression or tumor growth, the follow-up is a good indication, and decompression should be considered in facial nerve paralysis cases.

Postoperative hematoma can be a risk factor in delayed facial palsy after vestibular schwannoma resection via a retrosigmoid approach: a retrospective single-center cohort study.

Delayed facial palsy (DFP) is a rare postoperative complication after vestibular schwannoma (VS) surgery. The exact mechanism of DFP remains uncertain and the risk factors for DFP are still controversial. The authors aimed to investigate the characteristics, risk factors, and etiology of DFP after VS resection retrospectively. Ninety-one consecutive surgeries with VS were analyzed. Patients with neurofibromatosis 2 in eight surgeries and postoperative facial palsy House-Brackmann (HB) grade more than 3 in two surgeries were excluded. Eighty-one surgeries were included in this research. Facial nerve function was evaluated using the HB grade. Delayed facial palsy was defined as deterioration in the facial function of at least 1 HB grade more than 1day after undergoing VS resection. The characteristics of patients with VS and risk factors for DFP were analyzed. All surgeries were performed via a retrosigmoid approach. DFP was observed in nine patients. There were no statistically significant differences between the DFP group and non-DFP group in terms of the following characteristics: sex, age, side, size, Koos grading system, postoperative facial palsy, or extent of resection. Postoperative hematoma in the cerebellopontine angle (CPA) cistern was significantly higher in the DFP group than in the non-DFP group (p = 0.0023), and was significantly associated with DFP after VS surgery (odds ratio 18.40, p < 0.001). DFP improved in seven patients, but two patients did not improve. DFP occurred in 11.1% of patients after VS surgery. This study revealed that postoperative hematoma in the CPA cistern was significantly associated with DFP after VS surgery.

MRI measurements the linear volume of posterior cranial fossa in patients with hemifacial spasm

To explore the pathogenesis of hemifacial spasm (HFS) and the effect of posterior fossa volume on postoperative complications. The measurements of the antero-posterior diameter of foramen magnum, the length of supraocciput, the angle of tentorium cerebelli, clivus and occipital bone were performed on MRI. The data of measurements and postoperative complications were then analyzed and statistically examined. The antero-posterior diameter of the foramen magnum was smaller in HFS group (34.98 ± 2.83) mm than in control group (35.83 ± 2.67) mm (P < 0.05); The length of supraocciput was smaller in HFS group (44.67 ± 4.48) mm than in control group (45.84 ± 4.25) mm (P < 0.05); The angle of tentorium cerebelli was larger in HFS group (41.03 ± 5.01)°than in control group (37.28 ± 4.31)° (P < 0.05); The angle of clivus was smaller in HFS group (52.71 ± 6.22)° than in control group (56.39 ± 6.61)° (P < 0.05). The operation time was significantly longer in crowding group (107.90 ± 26.20) min than in non-crowding group (96.48 ± 20.52) min (P < 0.05); The incidence of postoperative facial paralysis was significantly higher in crowding group (16.19%) than in non-crowding group (7.20%) (P < 0.05); The incidence of postoperative hearing loss was significantly higher in crowding group (13.33%) than in non-crowding group (4.00%) (P < 0.05). Factors such as shorter antero-posterior diameter of foramen magnum, lower tentorium cerebelli, and shorter length of supraocciput in patients with HFS indicate the posterior fossa dysplasia and promote the occurrence of HFS. The crowding of the posterior fossa will increase the difficulty of the surgery and the incidence of postoperative facial paralysis and hearing loss.

Reconstruction of lower and midfacial soft tissue defects with a submental island flap

This study aims to analyze the feasibility and utility of a submental island flap and to identify whether this flap procedure is a good choice for the reconstruction of lower and midfacial soft-tissue defects. This was a retrospective study that included 12 patients with lower and midfacial soft tissue defects, which were reconstructed using the submental island flap technique. The medical records of 12 patients who underwent reconstruction with submental island flaps from September 2015 to September 2020 were reviewed and included 11 patients with skin cancer and 1 patient with a history of trauma. The mean age of the patients was 64.9 years. The details of the flap harvest were studied for flap size, the procedure to elevate the flap, pedicle flow, and flap survival rate. In addition, information on demographics, histology, location, size, recurrence, and outcomes was recorded. All of the flaps survived. The skin paddle size ranged from 22 to 55 cm2 (mean size 33 cm2). Ten flaps were anterograde pedicle flaps and two flaps were retrograde pedicle flaps. All donor sites were closed using primary closure without any difficulty in neck movement. None of the patients had symptoms of postoperative facial palsy. There were no signs of any local or regional cancer recurrence. The mean follow-up time was 22.9 months. There was an esthetic appearance of graft sites. The submental island flap is a feasible and reliable option for the reconstruction of lower and midfacial defects, which provides good cosmetic results.

P 64 Evaluation of cortical reorganization in patients with facial palsy by navigated transcranial magnetic stimulation (nTMS) and functional MRI

Background: Bell’s palsy develops due to a lesion of the facial nerve and might occur idiopathic, as a result of masses in the cerebello-pontine angle or brainstem or as a result of trauma or surgery. This prospective study aims to evaluate cortical reorganization after facial nerve palsy by means of navigated transcranial magnetic stimulation (nTMS), diffusion tensor imaging (DTI) and resting state functional magnetic resonance imaging (rsfMRI). Methods: The study is based on a prospective patient and healthy subject cohort study. The patient group consist mainly of patients with tumors of the cerebello pontine angle suffering from a postoperative facial nerve palsy. The House & Brackmann scale, and Sunnybrook scale were used to assess the facial nerve function. The cortical excitability of the facial network was determined by navigated transcranial magnetic stimulation (nTMS) with the following parameters: Resting motor threshold (RMT), Recruitment curve (RC), Cortical silent period (CSP) and Motor area. By means of functional and diffusion MRI corticobulbar tract integrity and interhemispheric connectivity were displayed. Results: We present the first results of our ongoing trial. In these two patients we were able to detect a reduced cortical excitability expressed by an increased RMT interhemispheric ration (1,3; 0,6). The facial motor area of the affected hemisphere was reduced in size (218 mm2 vs. 355,1 mm2) and there was a diminished interhemispheric connectivity (pFWE (corr) = 0.03) Conclusion: By better characterization of neuronal recovery, risk groups of patients without clinical improvement can be defined early. This gives this group a better chance to receive early surgical facial nerve reconstruction, therefore resulting in a better functional outcome. Furthermore, evaluation of cortical excitability and representation of the facial motor network after surgery might also display postoperative recovery.