Value of intraoperative monitoring of the trigeminal nerve in detection of a superiorly displaced facial nerve during surgery for large vestibular schwannomas.

The aim of this study was to investigate the role of trigeminal and facial nerve monitoring in the early identification of a superiorly (anterior and superior (AS)) displaced facial nerve. This prospective study included 24 patients operated for removal of large vestibular schwannomas (VS). The latencies of the electromyographic (EMG) events recorded from the trigeminal and facial nerve innervated muscles after mapping the superior surface of the tumor were analyzed. The mean latency of the recorded compound muscle action potential (CMAP) from the masseter muscle was 3.6 ± 0.5 ms and of the peripherally transmitted responses by volume conduction from the frontalis, o. oculi, nasalis, o. oris, and mentalis muscles was 4.6 ± 0.9, 4.1 ± 0.7, 3.9 ± 0.4, 4.3 ± 0.8, and 4.5 ± 0.6 ms, respectively, after trigeminal nerve stimulation in 24 (100%) patients (pattern I response). In 6 (25%) patients, the mean latency of CMAP on the masseter was 3.3 ± 0.3 ms, and the latencies of the CMAP from the frontalis, o. oculi, nasalis, o. oris, and mentalis muscles were 6.5 ± 1.3, 5.0 ± 1.5, 7.5 ± 1.3, 7.4 ± 0.6, and 7.0 ± 1.5 ms, respectively, longer than those of the peripherally transmitted responses (p = 0.002, p = 0.001, p < 0.001, and p = 0.015, respectively) indicating simultaneous stimulation of both nerves (pattern II response). All patients with this response were later confirmed to have an AS-displaced facial nerve. Recognizing the response resulting from simultaneous stimulation of both the facial and trigeminal nerves is important to help early identification of an AS-displaced facial nerve before it is visible in the surgical field and to avoid misleading information by confusing this pattern for a pure trigeminal nerve response.

COVID-19 and ear endoscopy in otologic practices.

PURPOSE: Otolaryngologists have had to postpone the majority of surgical procedures in the current COVID-19 pandemic. Airborne transmission, beyond the projection of droplets from upper airways, expose healthcare workers to a risk of viral infection. Aerosol generating procedures (AGP) increase the risk of viral transmission to staff within the operating room. METHODS: Surgery of middle ear and mastoid is also considered an AGP, particularly mastoidectomy performed using a high-speed drill. The authors report their experience in endoscopic ear surgery as an alternative technique to reduce AGP in otologic procedures. RESULTS: Transcanal endoscopic ear surgery is a reliable technique used to manage many otologic conditions. CONCLUSION: The endoscopic approach may reduce the risk of viral transmission to operating room staff by reducing the need for mastoidectomy.

Surgery for traumatic facial nerve paralysis: does intraoperative monitoring have a role?

The use of intraoperative facial nerve (FN) monitoring during surgical decompression of the FN is underscored because surgery is indicated when the FN shows more than 90 % axonal degeneration. The present study proposes including intraoperative monitoring to facilitate decision taking and provide prognostication with more accuracy. This prospective study was conducted on ten patients presenting with complete FN paralysis due to temporal bone fracture. They were referred after variable time intervals for FN exploration and decompression. Intraoperative supramaximal electric stimulation (2-3 mA) of the FN was attempted in all patients both proximal and distal to the site of injury. Postoperative FN function was assessed using House-Brackmann (HB) scale. All patients had follow-up period ranging from 7 to 42 months. Three different patterns of neurophysiological responses were characterized. Responses were recorded proximal and distal to the lesion in five patients (pattern 1); only distal to the lesion in two patients (pattern 2); and neither proximal nor distal to the lesion in three patients (pattern 3). Sporadic, mechanically elicited EMG activity was recorded in eight out of ten patients. Patients with pattern 1 had favorable prognosis with postoperative function ranging between grade I and III. Pattern 3 patients showing no mechanically elicited activity had poor prognosis. Intraoperative monitoring affects decision taking during surgery for traumatic FN paralysis and provides prognostication with sufficient accuracy. The detection of mechanically elicited EMG activity is an additional sign predicting favorable outcome. However, absence of responses did not alter surgeon decision when the nerve was found evidently intact.

Fusion of Diffusion-Weighted Magnetic Resonance Imaging and High-Resolution Computed Tomography Scan As a Preoperative Tool for Classification of Middle Ear Cholesteatoma.

BACKGROUND: The role of imaging in cholesteatoma continues to evolve with excellent bony details provided by high-resolution computed tomography and high soft tissue identification for cholesteatoma by diffusion-weighted magnetic resonance imaging. The fusion of highresolution computed tomography and diffusion-weighted magnetic resonance imaging combines the advantages of both imaging techniques. METHODS: A random sample of 40 consecutive patients with chronic suppurative otitis media with cholesteatoma was included in this study. Both high-resolution computed tomography of the petrous bone and non-echoplanar diffusion-weighted magnetic resonance imaging were performed. This was followed by their fusion. Patients were classified according to The European Academy of Otology and Neurotology, in cooperation with the Japanese Otological Society Joint Consensus Statement on the Definitions, Classification, and Staging of Middle Ear Cholesteatoma. All patients were operated, and the technique was tailored according to the data obtained from the preoperative fusion of computed tomography and diffusion-weighted magnetic resonance imaging and the intraoperative findings. RESULTS: Patients were equally divided between males and females with a mean age of 26.8 years of which 52.5% were left-sided ears. The fusion of high-resolution computed tomography and diffusion-weighted magnetic resonance imaging had a 100% sensitivity and 88.9% specificity regarding The European Academy of Otology and Neurotology, in cooperation with the Japanese Otological Society classification. On the other hand, it showed 100% specificity and 100% sensitivity for all middle ear subsites except sinus tympani which obtained 55.56% sensitivity and 100% specificity. In all patients with preoperative fusion showing cholesteatoma not reaching the mastoid antrum (30%), exclusive endoscopic approach was employed, and no postauricular incision was needed. CONCLUSION: The fusion of high-resolution computed tomography and diffusion-weighted magnetic resonance imaging images is an accurate tool for localizing cholesteatoma in various middle ear cleft subsites. This makes it a valuable tool for cholesteatoma classification and staging and surgical planning preoperatively.

Transcanal Endoscopic Management of Glomus Tympanicum: Multicentric Case Series.

OBJECTIVE: The aim of this study was to report a multicentric surgical experience in the exclusive endoscopic management of glomus tympanicum (GT). STUDY DESIGN: Retrospective case series review at two institutions. SETTING: Tertiary referral centers. PATIENTS: The study included 30 patients who underwent exclusive transcanal excision of GT between 2010 and 2017 at the two referral centers. INTERVENTIONS: Exclusive endoscopic transcanal excision of GT type A1, A2, and B1 (modified Fisch-Mattox classification). All surgical procedures were performed by two senior surgeons (L.P.; M.B.). MAIN OUTCOME MEASURES: For each procedure, intraoperative features of the disease, postoperative complications, and functional outcomes were evaluated. Recurrent or residual diseases were clinically and radiologically assessed during the follow-up period. RESULTS: None of the patients treated with transcanal endoscopic approach (TEA) experienced intraoperative complications, nor required conversion to microscopic approach. Gross total resection (GTR) was obtained in 90% of the cases, while a near total resection was advocated when the residual pathology had a close relationship with the internal carotid artery. Mean hospitalization time was 1.6 (±0.8 SD) days and no postoperative complications were reported. No recurrences were reported in the GTR group after a mean follow-up period of 38.1 (±28.7 SD) months. CONCLUSIONS: Middle ear paragangliomas with no mastoid involvement (Class A1, A2, and B1) can be safely managed by means of a transcanal endoscopic approach. Low rate of postoperative complications, short hospitalization, and high rate of gross total resection demonstrate that TEA is a safe and effective procedure.

Petrous apex non-secretory plasma cell myeloma with aberrant cytokeratin expression.

Multiple myeloma is a monoclonal proliferation of plasma cells with common involvement of vertebrae, ribs and skull vault. However, involvement of skull base is relatively uncommon and myeloma manifesting initially as a petrous apex mass is distinctly rare. We report a rare case of non-secretory multiple myeloma in a 52-year-old Egyptian male presenting primarily as a right petrous apex mass with abducens nerve palsy. Additionally, neoplastic cells aberrantly expressed cytokeratin. Although rare, plasma cell myeloma should be considered in the differential diagnosis of petrous apex masses.

Endoscopic Facial Nerve Surgery.

Tympanic facial nerve segment surgery has been traditionally performed using microscopic approaches, but currently, exclusive endoscopic approaches have been performed for traumatic, neoplastic, or inflammatory diseases, specially located at the geniculate ganglion, greater petrosal nerve, and second tract of the facial nerve, until the second genu. The tympanic segment of the facial nerve can be reached and visualized using an exclusive transcanal endoscopic approach, even in poorly accessible regions such as the second genu and geniculate ganglion, avoiding mastoidectomy, bony demolition, and meningeal or cerebral lobe tractions, with low complication rates using a minimally invasive surgical route.

Multichannel facial nerve monitoring: value in detection of mechanically elicited electromyographic activity and prediction of postoperative outcome.

OBJECTIVE: To determine the value of using a multichannel facial nerve (FN) monitoring setup in detecting mechanically elicited EMG activity during vestibular schwannoma (VS) surgery. STUDY DESIGN: Prospective study. SETTING: Tertiary referral center. PATIENTS AND METHODS: This study was conducted on 42 patients operated for VS removal. The FN was monitored using a 5-channel setup with electrodes inserted in mentalis, o.oris, nasalis, o.oculi, and frontalis. The number of channels activated simultaneously in response to a particular event was recorded together with the amplitude of response on each muscle. EMG activity occurring simultaneously on all 5 channels was referred to as "all-channels activity." Postoperative FN function was assessed immediately and 1 year postoperatively using the House-Brackmann classification. RESULTS: The 5-channel setup detected a significantly higher number of mechanically elicited EMG activity than would have been possible using a 2-channel setup. The number and amplitude of EMG activity detected on the mentalis muscle was significantly higher compared with other muscles. Patients with higher percentage of events in which the mentalis fired while o.oris and o.oculi did not were more likely to develop a better long-term outcome. Positive correlation was found between the number of all-channels activity and postoperative outcome (p < 0.001). CONCLUSION: The use of a multichannel setup allowed earlier and efficient detection of mechanically elicited EMG activity. Including the mentalis muscle significantly increased the detection rate, which tended to reflect as improvement in the long-term outcome. The occurrence of all-channels activity should be considered a prompt warning sign.

Instrumentation and technologies in endoscopic ear surgery.

This article covers state-of-the-art instruments and devices specially designated for endoscopic ear surgery. New technologies stimulate the creation of special endoscopic equipment and microinstruments specially designed to satisfy the exclusive requirements of endoscopic ear surgery, which contribute to the progress of the procedure. The article presents the advantages and disadvantages of working with ear endoscopes and details the advances in equipment used in ear endoscopies. New instruments specially modified for working with angled-vision endoscopes and considerations of the surgeon's use of them are discussed.