Prognostic clinical and radiological parameters for immediate facial nerve function following vestibular schwannoma surgery

Objective  The paper aims to define the parameters available before surgery which could predict immediate facial nerve function after excision of a vestibular schwannoma (VS). Methods  Ninety-nine patients with VS operated consecutively by a single surgeon using an identical surgical technique have been evaluated retrospectively. Data were collected regarding patients' sex, age at onset of symptoms and at surgery, initial symptoms, neurological status at presentation, early post-operative neurological status and complications. The main radiological parameters included in the study were tumour extension pattern, diameters, shape, and volume, as well as extent of bony changes of the internal auditory canal. Results  As the tumour stage and volume increase, facial nerve function is worse after surgery (p < 0.001 and p < 0.05, respectively). Concomitantly, larger extra-meatal tumour diameters in three dimensions (sagittal, coronal and axial) led to worse function (p < 0.01). Anterior and/or caudal tumour extension (p = 0.001 and p = 0.004, respectively) had more significant correlation than posterior and/or cranial extension (p = 0.022 and p = 0.353, respectively). Polycyclic VS had the worst prognosis, followed by the tumours with oval shape. The extent of intra-meatal tumour growth does not correlate with immediate facial nerve outcome. The different angles, lengths and diameters of the internal auditory channel showed no significant correlation with facial nerve outcome. Patients with headache as an initial symptom and those with gait instability and/or pre-operative poor facial nerve function had significantly worse immediate facial nerve outcome. Conclusion  Our data suggests that the analysis of the radiological and neurological patient data prior to surgery could give reliable clues regarding the immediate post-operative facial nerve function.     

The preservation of hearing and facial nerve function in a consecutive series of unilateral vestibular nerve schwannoma surgical patients (acoustic neuroma)

Between January 1981 and February 1992, 102 non-NF-2 patients underwent removal of a unilateral vesitbular schwannoma. There were 54 women and 48 men. Eighty-six percent of patients with normal facial function preoperatively retained normal function (House score 1 or 2) postoperatively. Of the 64 patients with a functional cochlear nerve preoperatively, five had normal hearing (PTA < 25 dB, SB > 70%), five had near normal hearing (PTA < 45 dB, SD > 70%), four patients had preserved hearing (PTA < 50 dB, SD > 50%), and three patients had preserved cochlear nerve function (PTA > 50 dB, SD < 50%) after surgery. Hearing preservation was obtained in patients whose tumors were larger than 3 cm. Radiological follow-up revealed 10 patients with recurrent tumor, all but one asymptomatic.     

Greater superficial petrosal nerve neurinoma. Case report.

The authors report a case of middle cranial fossa neurinoma arising from the left greater superficial petrosal nerve in a 21-year-old woman who presented with a left-sided otitis media that chronically recurred over a period of 5 years. On examination, the patient had a left-sided mild conductive hearing impairment and a slight disturbance in tear secretion on the left side, with sensory disturbance in the left palate. Three-dimensional computerized tomography scans clearly demonstrated the enlargement of the foramen lacerum and foramen ovale, and heavily T2-weighted magnetic resonance images revealed the tumor's location along with the course of the greater superficial petrosal nerve and its extension into the tympanic cavity. Following complete surgical excision of the tumor and tympanoplasty via a middle cranial fossa approach, the patient retained useful hearing without facial palsy.     

Malignant schwannoma in the posterior tibial nerve

Our group have studied a patient affected by a malignant schwannoma in the posterior tibial nerve. Schwannomas are uncommon neoplasms that originate from the Schwann cells of the peripheral nerves: the most common forms are benign. Malignant transformation is rarer. The therapy is surgical and the operation undertaken, if possible, should be the amputation. Alternatively, where amputation is not possible due to the specific localisation or due to patient refusal, the alternative must be the largest and most radical excision possible.     

Plexiform schwannoma of the ulnar nerve

Plexiform schwannoma is a rare benign neurogenic tumour; we report a case that arose in the ulnar nerve of a 59-year-old woman. Exploration showed a continuous multinodular tumour that involved the ulnar nerve from the hand to the upper arm; the length of the tumour was 35 cm.     

Intra-osseous sphenoorbital schwannoma

Summary. A 40-year-old man without stigmata of neurofibromatosis presented with proptosis and impairment of lateral gaze of the left eye. Neuro-imaging studies revealed an extra-axial lytic spheno-orbital mass. The mass was completely removed. Classic schwannoma was documented histopathologically.Schwannosis or hyperplasia of Schwann cells of perivascular nerve plexus may be attributed in the histogenesis of this unusually located schwannoma.     

An intrathoracic vagus nerve schwannoma invading the trachea

A patient with a schwannoma of the intrathoracic vagus nerve is presented. The tumor invaded the trachea and caused dyspnea. It was successfully excised by a segmental resection of the trachea with end-to-end anastomosis. This instance of an intrathoracic vagus tumor invading the trachea is, as far as we know, the first reported in the world.     

Malignant epithelioid peripheral nerve sheath tumor arising in a benign schwannoma

The case of a patient with malignant degeneration of a solitary abdominal schwannoma and endobronchial metastasis is presented. The patient presented clinically with dyspnea referable to her lung mass, anorexia, and night sweats. The lung mass, initially diagnosed as a large-cell undifferentiated carcinoma, was later found to be histologically identical to the malignant portion of the abdominal tumor. The light microscopic, electron microscopic, and immunoperoxidase staining characteristics of the tumor are reported, and previous reports in the literature are reviewed.     

Peduncular hallucinosis after sacrifice of veins of the petrosal venous complex for trigeminal neuralgia

Summary  Peduncular hallucinosis is characterized by striking visual images, highly colored and mobile, which are recognized by the patient as imaginary. A 50-year-old-man underwent microvascular decompression for a classical right sided trigeminal neuralgia. During the procedure, the petrosal vein and a transverse pontine vein were sacrificed for trigeminal decompression. On the second postoperative day, the patient developed peduncular hallucinosis that disappeared on the forth postoperative day. This is the third case in the literature of peduncular hallucinosis after obliteration of veins of the petrosal venous complex for trigeminal neuralgia. The best policy in cerebellopontine angle surgery is to preserve the petrosal vein whenever possible to avoid complications related to venous congestion.     

Intracranial intraparenchymal schwannoma: Report of three cases

Summary Intracranial intraparenchymal schwannomas are rare. We report three patients with an intracranial intraparenchymal schwannoma and discuss the clinical and neuroradiological aspects of this particular tumour. The patients were a 21-year-old male, a 64-year-old female and a 17-year-old male. The tumours were located in cerebrum in two patients and the cerebellum in one patient. Computerized tomography (CT) scans demonstrated a slightly high density area with homogeneous enhancement by contrast medium. Magnetic resonance imaging (MRI) showed slightly low signal intensity on the T1-weighted image, high or mixed signal intensity on the T2-weighted image and homogeneous enhancement by gadolinium diethylene triamine penta-acetic acid (Gd-DTPA). Radiological studies revealed cystic components in 2 of the 3 patients. All tumours were firm, well-demarcated, and completely removed. The diagnosis of schwannoma was derived from histological and immunohistochemical studies in all 3 cases; 2 cases were also examined by electron microscopy.     

Greater auricular nerve neuropraxia with beach chair positioning during shoulder surgery

Neuropraxia of the greater auricular nerve is an uncommon complication of shoulder surgery, with the patient in the beach chair position. The greater auricular nerve, a superficial branch of the cervical plexus, is vulnerable to neuropraxia due to its superficial anatomical location. In this case series, we present three cases of neuropraxia associated with direct compression by a horseshoe headrest, used in routine positioning for uncomplicated shoulder surgery. We outline the risk of using devices of this nature and discourage the use of similar headrest devices due to the potential complications in headrest devices that exert pressure on the posterior auricular area to maintain head position during surgery.     

下颌舌骨神经与面神经吻合的应用解剖

目的　为确保面神经与下颌舌骨神经顺利吻合提供参考。方法　在 2 5具 (5 0例 )尸头上解剖观察了下颌舌骨神经在颌下的走行、分支及双侧分支吻合情况。结果　下颌舌骨神经从下齿槽神经分出后在下颌舌骨沟内至下颌骨下缘处为第一段。从下颌骨下缘向前行至第一次分支为第二段 ,其长度为 13.6 1± 3.0 9mm ,直径为 1.2 1± 0 .14mm。从第一次分支后分别至二腹肌前腹与下颌舌骨肌的各分支为第三段 ,其中至二腹肌前腹支长度为 13.0 7±2 .49mm ,直径为 1.0 3± 0 .12mm ,至下颌舌骨肌支长度为 11.2 1± 1.75mm ,直径为 1.0 4± 0 .11mm。两侧之间有吻合。结论　该神经易于暴露 ,走行及分支均较恒定。适合于进行神经吻合。     

Facial nerve function and hearing preservation after retrosigmoid excision of vestibular schwannoma: Christchurch Hospital experience with 97 patients

BACKGROUND: Between January 1988 and December 2002, 97 patients underwent surgery for excision of vestibular schwannoma via the retrosigmoid approach at Christchurch Hospital. METHODS: A retrospective review was undertaken of the clinical notes with emphasis on facial nerve function and hearing preservation postoperatively. RESULTS: Of patients with small and medium-sized tumours, 81% had good facial nerve function at 1 year (House-Brackmann grade 1 and grade 2), 16% had moderate function (grade 3 and grade 4) and 3% had poor function (grade 5). Of patients with large tumours, 22% had good facial function (grade 1 and grade 2), 37% had moderate function (grade 3 and grade 4) and 41% had poor function (grade 5 and grade 6). Useful postoperative hearing was preserved in 21% of the 47 patients with tumours <3 cm and useful preoperative hearing. In the last 5 years the authors have been operating in conjunction with an ear, nose and throat surgeon (PAB) trained in base-of-skull surgery. Over this period, useful hearing was preserved in 32% of patients with small and medium-sized tumours and useful preoperative hearing. CONCLUSIONS: Tumour size was an important predictor of the postoperative facial and cochlear nerve function. The multidisciplinary approach to these tumours offers better results. These results compare well with other published series.     

腹膜后神经鞘瘤1例报告并文献复习

目的报告1例腹膜后神经鞘瘤,并复习相关文献,分析其临床诊治现状。方法通过对1例腹膜后神经鞘瘤的诊断、治疗方法及术后病理、随访的回顾,结合国内外有关文献报道,综合分析腹膜后神经鞘瘤的诊断及治疗状况。结果本例行手术治疗,术后病理证实为腹膜后神经鞘瘤,随访半年无复发。结论腹膜后神经鞘瘤诊断困难,影像学检查无特异性,确诊依靠病理检查,理想的治疗方法是通过外科手术完整切除肿瘤,其预后良好,早期复发率低。     

Microsurgical Localization of the Cochlea in the Extended Middle Fossa Approach

Objective In the extended middle fossa approach, a portion of the petrous bone known as Kawase''s rhomboid can be drilled to expose the posterior fossa through a middle fossa corridor. During this bony resection, the cochlea is placed at risk. The objective of this study was to objectively detail the position of the cochlea in relation to reliable surgical landmarks.Methods Eleven cadaveric specimens were dissected—including six cadaveric heads and five dry temporal bones by means of an anterior petrosectomy with skeletonization of the cochlea. Three anatomic measurements describing the location of the cochlea in relation to the extrapolated intersection of the greater superficial petrosal nerve (GSPN) and facial nerve were recorded. These measurements were then correlated with thin-cut temporal bone computed tomography scans from 25 patients with morphologically normal inner ears.Results In the cadaveric specimens, the anterior border of the membranous basal turn of the cochlea was located an average of 7.56 mm (6.4 to 8.9 mm) anterior to the extrapolated junction of the GSPN and facial nerve, as measured along the course of the GSPN. The medial border of the membranous cochlea (medial margin of basal turn) was located an average of 8.2 mm (6.9 to 8.9 mm) medial to the extrapolated junction of the GSPN and facial nerve, as measured along the course of the facial nerve. The average maximum distance from the extrapolated junction of the GSPN and facial nerve to the membranous cochlea was 9.3 mm (8.2 to 10.3 mm). These anatomic measurements correlated well with radiologic measurements of the same parameters.Conclusion When drilling Kawase''s rhomboid, it is useful to locate the extrapolated junction of the GSPN and the facial nerve. Drilling of the anteromedial petrous bone outside of a radius of 12.5 mm from the extrapolated junction of GSPN and facial nerve appears to be associated with a low degree of risk to the cochlear apparatus.     

Ancient schwannoma of the hand

Ancient schwannoma is a schwannoma subtype, characterized by extensive degeneration and diffuse hypocellular areas. These changes are believed to occur because it takes a long time for ancient schwannomas to develop. Schwannomas with these degenerative changes can be misdiagnosed as sarcomas or other soft-tissue neoplasms. We present a case of a slowly enlarging ancient schwannoma of the thenar area in a 67-year-old woman. The differential diagnosis included atypical soft tissue sarcomas and tumors of neural origin. The combination of ultrasound and magnetic resonance imaging findings provided features that narrowed the differential diagnosis, and histology confirmed the presence of an encapsulated schwannoma with extensive myxomatous degeneration and multiple vessel thrombosis. The clinical, radiological, and histological features and the diagnostic approach of this rare entity are described.     

Cystic versus solid vestibular schwannomas: a series of 80 grade III–IV patients

Cystic acoustic neuromas are less frequent than solid ones and present different clinical and radiological features. Cystic schwannomas are larger, show a shorter clinical history and a different risk of postoperative complications. This study was designed to compare surgical results and complications of solid and cystic vestibular schwannomas of matching size operated upon via either a retrosygmoid or a translabyrinthine approach. The study included 80 patients presenting with grade III and IV acoustic vestibular schwannomas referred to the Neurosurgical and ENT team in the Department of Neuroscience of Torino, Italy. Twenty-six were cystic and 54 were solid tumours. Clinical history, surgical results and complications were compared between the two groups. In cystic tumors, rapid clinical worsening is common, due to sudden expansion of cystic elements. Tighter adherences are found between cystic tumours and nervous elements (particularly brainstem and possibly facial nerve), once compared to solid ones. Operative morbidity appears to be higher in cystic tumours. A wait and see policy should not to be applied to patients with cystic tumours. Careful technique, possibly sharp dissection, to divide the tumour adherences from the nervous tissue must be employed, in order to avoid lesions on brainstem veins and traction on a thin facial nerve. Severe complications may be caused by the excessive efforts to dissect brainstem adherences.