Optimized preoperative determination of nerve of origin in patients with vestibular schwannoma

In vestibular schwannoma (VS) patients hearing outcome and surgery related risks can vary and depend on the nerve of origin. Preoperative origin differentiation between inferior or superior vestibular nerve may influence the decision on treatment, and the selection of optimal treatment and counselling modalities. A novel scoring system based on functional tests was designed to predict the nerve of origin for VS and was applied to a large number of consecutive patients. A prospective, double blind, cohort study including 93 patients with suspected unilateral VS was conducted at a tertiary referral centre. Preoperatively before tumor resection a functional test battery [video head-impulse test (vHIT) of all semicircular canals (SCC)], air-conducted cervical/ocular vestibular evoked myogenic potential tests (cVEMP, oVEMP), pure-tone audiometry, and speech discrimination was applied. Sensitivity and specificity of prediction of intraoperative finding by a preoperative score based on vHIT gain, cVEMP and oVEMP amplitudes and asymmetry ratios was calculated. For the prediction of inferior vestibular nerve origin, sensitivity was 73% and specificity was 80%. For the prediction of superior vestibular nerve origin, sensitivity was 60% and specificity was 90%. Based on the trade-off between sensitivity and specificity, optimized cut-off values of − 0.32 for cVEMP and − 0.11 for oVEMP asymmetry ratios and vHIT gain thresholds of 0.77 (anterior SCC), 0.84 (lateral SCC) and 0.80 (posterior SCC) were identified by receiver operator characteristic curves. The scoring system based on preoperative functional tests improves prediction of nerve of origin and can be applied in clinical routine.

Head-Neck Schwannoma: Presenting as a Huge Posterior Neck Swelling

Schwannomas are benign slow growing tumors that arise from the Schwann cells of nerve, also called neurilemmoma. Head and Neck schwannomas usually present as solitary with well demarcated lesions. These tumors usually remain asymptomatic but present as slowly enlarging neck masses. Its origin is only determined during surgical procedure along the course and distribution of the nerve. Preoperative diagnosis is usually made by physical examination and aided by ultrasonography, magnetic resonance imaging or computed tomography and fine needle aspiration cytology but open biopsy is not recommended. The main stay of treatment is complete intracapsular excision with preserving the nerve of origin.

Schwannomas of ear, nose, throat and neck

Schwannoma is a benign tumour of nerve sheath origin with latent malignant potential. All cranial nerves can give rise to schwannoma except for olfactory and optic nerves, which are devoid of Schwann cell. Schwanommas are usually asymptomatic and present late owing to compression of nerve of origin. We present our study of 19 cases of schwannoma arising from unusual sites in head and neck, having varied presentation and the challenges faced in management of these cases. These cases presented in detail to the department of Ear, Nose and Throat, KEM Hospital, and were thoroughly evaluated clinically and radiologically to formulate a management strategy. Schwannoma of the head and neck is a rare entity but should be considered as differential diagnosis in unilateral nasal mass cases, palatal masses, anterior and lateral neck masses. Nerve of origin may not always be clear preoperatively but the possibility of postoperative loss of nerve function should be kept in mind. Radiological investigations like computed tomography scan and magnetic resonance imaging play a pivotal role in management. In case of nonvascular neck tumours, fine needle aspiration cytology is crucial but has low accuracy in the diagnosis of neural tumors. Histopathology of excised tumour remains the gold standard in diagnosis.

Neglected left intraparotid facial nerve schwannoma causing complete facial nerve palsy: A case report

Extracranial schwannomas in the head and neck region are relatively rare neoplasms. The tumours are slow growing and often unnoticeable. The nerve of origin is unable to be determined until the time of surgery. Proper preoperative assessment of the disease can be done by imaging studies such as magnetic resonance imaging. The treatment for these tumours is surgical resection with preservation of the neural pathway. We report a case of left intraparotid facial nerve schwannoma in a middle-aged lady causing complete facial nerve paralysis. The clinical features, diagnostic possibilities and management are discussedBangladesh Journal of Medical Science Vol.17(4) 2018 p.680-682

Video Head Impulse Test to Preoperatively Identify the Nerve of Origin of Vestibular Schwannomas

BACKGROUNDIdentification of the nerve of origin in vestibular schwannoma (VS) is an important prognostic factor for hearing preservation surgery. Thus far, vestibular functional tests and magnetic resonance imaging have not yielded reliable results to preoperatively evaluate this information. The development of the video head impulse test (vHIT) has allowed a precise evaluation of each semicircular canal, and its localizing value has been tested for some peripheral vestibular diseases, but not for VS.OBJECTIVETo correlate patterns of semicircular canal alteration on vHIT to intraoperative identification of the nerve of origin of VSs.METHODSA total 31 patients with sporadic VSs were preoperatively evaluated with vHIT (gain of vestibule-ocular reflex, overt and covert saccades on each semicircular canal) and then the nerve of origin was surgically identified during surgical resection via retrosigmoid approach. vHIT results were classified as normal, isolated superior vestibular nerve (SVN) pattern, isolated inferior vestibular nerve (IVN) pattern, predominant SVN pattern, and predominant IVN pattern. Hannover classification, cystic component, and distance between the tumor and the end of the internal auditory canal were also considered for analysis.RESULTSThree patients had a normal vHIT, 12 had an isolated SVN pattern, 5 had an isolated IVN pattern, 7 had a predominant SVN pattern, and 4 had a predominant IVN pattern. vHIT was able to correctly identify the nerve of origin in 89.7% of cases (100% of altered exams).CONCLUSIONThe pattern of semicircular canal dysfunction on vHIT has a localizing value to identify the nerve of origin in VSs.

A novel technique to identify the nerve of origin in head and neck schwannomas

Objective:Identifying the nerve of origin in head and neck schwannomas is a diagnostic challenge. Surgical management leads to a risk of permanent deficit. Accurate identification of the nerve would improve operative planning and patient counselling.Methods:Three patients with head and neck schwannomas underwent a diagnostic procedure hypothesised to identify the nerve of origin. The masses were infiltrated with 1 per cent lidocaine solution, and the patients were observed for neurological deficits.Results:All three patients experienced temporary loss of nerve function after lidocaine injection. Facial nerve palsy, voice changes with documented unilateral same-side vocal fold paralysis, and numbness in the distribution of the maxillary nerve (V2), respectively, led to a likely identification of the nerve of origin.Conclusion:Injection of lidocaine into a schwannoma is a safe, in-office procedure that produces a temporary nerve deficit, which may enable accurate identification of the nerve of origin of a schwannoma. Identifying the nerve of origin enhances operative planning and patient counselling.

Head and Neck Schwannomas: A Surgical Challenge—A Series of 5 Cases

Background. Schwannomas, also known as neurilemmomas, are benign peripheral nerve sheath tumors. They originate from any nerve covered with schwann cell sheath. Schwannomas constitute 25–45% of tumors of the head and neck. About 4% of head and neck schwannomas present as a sinonasal schwannoma. Brachial plexus schwannoma constitute only about 5% of schwannomas. Cervical vagal schwannomas constitute about 2–5% of neurogenic tumors. Methods. We present a case series of 5 patients of schwannomas, one arising from the maxillary branch of trigeminal nerve in the maxillary sinus, second arising from the brachial plexus, third arising from the cervical vagus, and two arising from cervical spinal nerves. Result. Complete extracapsular excision of the tumors was achieved by microneurosurgical technique with preservation of nerve of origin in all except one. Conclusion. Head and neck schwannoma though rare should be considered as a differential diagnosis of a unilateral slow growing mass in the head and neck region, particularly in an adult. Schwannomas are always a diagnostic dilemma as they are asymptomatic for long time, and histopathology is the gold standard for diagnosis. As a rule, treatment is surgical and dictated by the location of the tumor and nerve of origin. Due to its rarity, complex anatomical location and morbidity risk postexcision, they can pose a formidable challenge to surgeons. This study aims to describe the presentation, workup, surgical technique, and outcome.