Prognostic Factors of Long-Term Hearing Preservation in Small and Medium-Sized Vestibular Schwannomas After Microsurgery.

OBJECTIVE: The authors evaluated the long-term hearing outcomes of patients with vestibular schwannoma (VS) to explore appropriate surgical treatment. STUDY DESIGN: Retrospective study. SETTING: Tertiary referral center. PATIENTS: A total of 138 patients diagnosed with small and medium-sized VS with serviceable hearing from January 2006 to December 2015. INTERVENTIONS: All patients underwent microsurgery via retrosigmoid (RSA) or middle cranial fossa approach (MFA) and were followed up for over 2 years. MAIN OUTCOME MEASURES: Pre- and postoperative hearing, including pure tone audiometry, speech discrimination score, and auditory brainstem response (ABR), were analyzed. RESULTS: The mean tumor size and volume were 16.6 ±â€Š3.4 mm and 1711.8 ±â€Š918.5 mm, respectively. Preoperative hearing levels were Class A in 42, Class B in 67, and Class C in 29 patients. Patients with a tumor from the superior vestibular nerve (SVN) had better hearing at diagnosis. Postoperative hearing levels were Class A, B, C, and D for 28, 17, 32, and 61 patients. Hearing outcomes were significantly better in patients with normal intraoperative I wave on ABR. Hearing loss within 6 months had a positive effect on postoperative hearing. Better preoperative hearing and tumors from SVN were correlated with better postoperative hearing outcomes. Tumor size, cystic variation, or extension to the fundus of internal auditory canal had no influence on hearing preservation. CONCLUSIONS: Better preoperative hearing, shorter hearing loss period, tumors from SVN, and normal intraoperative I wave are prognostic factors for serviceable hearing. RSA and MFA are effective and safe for tumor removal and hearing preservation.

[Mini-orbitozygomatic craniotomy in surgery for supratentorial aneurysms and tumors of the anterior and middle cranial fossae]. / Minimal'naya orbitozigomaticheskaya kraniotomiya v khirurgii supratentorial'nykh anevrizm i obrazovanii perednei i srednei cherepnykh yamok.

UNLABELLED: Progress in microneurosurgical techniques, neuroanesthesiology, and intraoperative imaging enables surgery using small incisions and craniotomy, in accordance with the keyhole surgery concept. Supraorbital craniotomy is the most widespread minimally invasive approach. There are a number of supraorbital craniotomy modifications, regarding different soft tissue incisions and the extent of craniotomy. We present the first results of using mini-orbitozygomatic craniotomy for aneurysms of the anterior circle of Willis and space-occupying lesions of the anterior and middle cranial fossae performed through an eyebrow incision. MATERIAL AND METHODS: Forty five patients were operated on using mini-orbitozygomatic (MOZ) craniotomy in the period between March 2014 and December 2015. Fifteen supratentorial aneurysms were clipped, and 30 space-occupying lesions were resected. Most patients had unruptured aneurysms (10 patients). Five patients had a history of SAH. The aneurysm localization was as follows: 8 anterior communicating artery aneurysms, 4 aneurysms of the internal carotid artery in the area of the posterior communicating artery orifice, and 3 ophthalmic aneurysms. The Hunt-Hess scale was used to evaluate the patients' condition, and the Fisher scale was used to quantify SAH volume. Surgery was performed 14 days after SAH, on average. Contrast-enhanced MRI of the brain was the diagnostic method of choice in a group of patients with space-occupying lesions within the anterior and middle cranial fossae. In some cases, patients underwent CT with reconstruction for assessment of the skull base bone structures. The mean age of patients was 58.3 years. RESULTS: All aneurysms were completely excluded from the cerebral blood flow. No serious complications and deaths in a group of aneurysm patients occurred. Complete tumor removal was performed in 28 patients. Two patients having pituitary macroadenomas with supra- and parasellar spread underwent subtotal resection due to adenoma invasion into the cavernous sinus. Mortality in this group was 3.3% (1 patient). Postoperative complications were evaluated after 2 weeks and 6 months. The postoperative cosmetic result after 3 and 6 months after surgery was assessed by patients as excellent. CONCLUSION: Mini-orbitozygomatic craniotomy is an alternative to classic approaches and can be assistive in surgery for skull base aneurysms and tumors. Selection of candidates for this keyhole surgery should be based on their critical assessment.

Middle Cranial Fossa Dehiscence as an Incidental Finding on CT.

OBJECTIVES: This retrospective chart review demonstrates that the prevalence of middle cranial fossa (MCF) dehiscence on computed tomography (CT) scans increases with age. METHODS: High-resolution temporal bone CT scans, which had been obtained for any otologic complaint, were reviewed independent of all clinical history. Scans showing soft tissue, fluid, trauma, or previous operations were excluded. The CTs from 183 patients (296 ears) were reviewed, blinded for age and body mass index (BMI). The MCF floor was divided into 7 regions and systematically inspected. Ages and BMIs of the patients were subsequently extracted from the medical record. RESULTS: Logistic regression analysis confirmed increasing MCF dehiscence with age (P < .05, odds ratio [OR] = 1.07, R = .584). Over all ages (range, 1-88 years; average, 38.5), 32% of MCF floors were dehiscent at any 1 site. For age 60 and over, 55% were dehiscent. The most common sites of MCF dehisence were directly above the malleus head and above the additus ad antrum (35% and 28%, respectively). Superior canal dehiscence (SCD) was seen in 7% of all patients and only in the context of MCF dehiscence. The prevalence of MCF dehiscence increased with age when patients were analyzed by BMI <25, BMI = 25-30, and BMI >30 (P < .003, P < .04, P = .03). CONCLUSION: The increase of middle cranial fossa dehiscence with respect to age is statistically significant. Over all ages, approximately 32% of ears show dehiscence. Over 60 years, approximately 55% show dehiscence. The odds of having dehiscence double with a 10-year difference in age. The most common sites along the MCF floor are in the epitympanum over the malleus head and the additus ad antrum. There was a statistically significant increase in MCF dehiscence with age when patients with equivalent BMIs are compared.

Clinical characteristics and surgical outcomes of patients presenting with meningiomas arising predominantly from the floor of the middle fossa.

BACKGROUND: Little is known regarding meningiomas that primarily arise from the floor of the middle fossa as opposed to the sphenoid wing, the cavernous sinus, the anterior petrous ridge, or the lateral convexity dura. OBJECTIVE: Given the relative paucity of literature addressing this disease entity, we review the University of California at San Francisco (UCSF) experience with these tumors. METHODS: Between 1991 and 2006, 1228 patients were seen by neurosurgeons at UCSF for meningiomas of which 17 (1.1%) patients met our criteria for a "middle fossa floor" meningioma, of which 15 underwent first-time surgery and were included in this series. The most common presenting symptoms were headache (9 patients), seizures (6 patients), trigeminal nerve dysfunction (5 patients), hearing loss (5 patients), gait disturbance (5 patients), and cognitive decline (3 patients). All patients underwent surgical resection via frontotemporal craniotomy, with or without orbitozygomatic osteotomy. RESULTS: We were able to achieve a Simpson grade 1 or 2 resection in 10 of 15 patients (67%). The operative morbidity was clustered in 5 patients, as 10 of 15 patients (67%) experienced no operative morbidity. There were 4 known clinical recurrences in this group at 5 years median follow-up. All patients had either higher grade tumors, or received a Simpson grade 3 or higher resection. CONCLUSION: We present the clinical characteristics and surgical outcome of a series of patients presenting with meningiomas primarily arising from the concave floor of the middle cranial fossa. Given the relatively uncommon nature of these lesions, more investigation into the clinical behavior of this entity is warranted.

Rupture of middle fossa arachnoid cyst simulating new-onset migraine with aura.

Arachnoid cysts represent a common, innocent, finding in routine neuroimaging of headache patients. We present the first report of symptomatic migraine with aura caused by the spontaneous rupture of a middle fossa arachnoid cyst into the subdural space. Brain imaging enabled an accurate diagnosis and, subsequently, adequate surgical management.

Vascular compression of the trigeminal nerve is a frequent finding in asymptomatic individuals: 3-T MR imaging of 200 trigeminal nerves using 3D CISS sequences.

BACKGROUND: The aim of this study was to assess whether individuals without symptoms of trigeminal neuralgia exhibit vascular compression of the trigeminal nerve. This was investigated using ultra-high-field MR imaging. METHODS: One hundred subjects were imaged using a 3-T magnet and high-spatial-resolution three-dimensional (3D) MR imaging with 3D constructive interference in steady-state sequences. FINDINGS: Neurovascular compression (NVC) was detected in 92 of the individuals, with 83 cases bilateral and 9 unilateral. In total, 175 (87.5%) of the 200 nerves examined showed NVC. In 58% of the affected individuals, the vessel was compressing a site in the proximal third of the trigeminal nerve. Eighty-six percent of the compressing vessels were arteries, and 14% were veins. CONCLUSIONS: Ours is the first study to have evaluated NVC of the trigeminal nerve in asymptomatic individuals using 3-T MR imaging. The high prevalence of compression we observed is close to rates of NVC that have been documented in large series of microvascular decompression for trigeminal neuralgia. Our findings strongly suggest that vascular compression of the trigeminal nerve is not necessarily pathological.

Intraventricular haemorrhage caused by the rupture of a dural arteriovenous malformation of the middle cranial fossa.

Dural arteriovenous malformations of the middle cranial fossa are very rare. Venous drainage flows either through superficial leptomeningeal veins or through the sphenoparietal, sphenopetrous and/or sphenobasilar sinuses. They often have an aggressive course and therefore poor outcome. It is essential to analyse and understand the angioarchitecture of the dural arteriovenous malformations in order to select and plan the correct treatments. We describe an exceptional case of intraventricular haemorrhage caused by the rupture of a dural arteriovenous malformation of the middle cranial fossa. To our knowledge, this is the first case report of such characteristics described in the literature.

Spontaneous resolution of a Meckel's cave arachnoid cyst causing sixth cranial nerve palsy.

A 32-year-old pregnant woman developed a progressive right sixth cranial nerve palsy as an isolated finding. Brain MRI disclosed a discrete lobulated lesion centered in the right Meckel's cave with intermediate signal on T1, high signal on T2, and diffusion characteristics similar to those of cerebrospinal fluid on apparent diffusion coefficient mapping. The initial radiologic diagnosis was schwannoma or meningioma. No intervention occurred. Shortly after cesarean delivery, the abduction deficit began to lessen spontaneously. One month later, the abduction deficit had further improved; 7 months later it had completely resolved. Repeat MRI after delivery failed to disclose the lesion, which was now interpreted as consistent with an arachnoid cyst arising within Meckel's cave. Twenty-one similar cases of Meckel's cave arachnoid cyst or meningocele have been reported, 7 found incidentally and 14 causing symptoms, 2 of which produced ipsilateral sixth cranial nerve palsies. All previously reported symptomatic patients were treated surgically. This is the first report of an arachnoid cyst arising from Meckel's cave in pregnancy and having spontaneous resolution.

Trigeminal schwannomas: experience with 68 cases.

Trigeminal schwannomas (TS) are rare. Only a couple of series involving a large number of cases have been reported. In the present study we aimed to analyse the clinical characteristics of TS, the surgical approaches used to treat TS, and the outcomes for patients undergoing surgical treatment for TS via retrospective analysis of departmental records. Data for 68 patients treated for TS in the Department of Neurosurgery at the All India Institute of Medical Sciences between January 1993 and December 2005 were analysed. Most patients were in the fourth decade of life, with the duration of symptoms ranging from 1 month to 13 years. Twenty-nine TSs were classified as type A, 13 as type B and 26 as type C, depending upon size. A skull base approach was used in every surgically treated case. Of the 46 patients for whom radiological follow-up data were available, complete tumour excision was achieved in 35 cases (76%). Follow-up ranged from 3 months to 12 years (mean 62 months). One patient died and nine (15%) had permanent morbidity in the form of corneal opacity (5) or facial (2) or trochlear (2) nerve palsy. We conclude that trigeminal neuromas are best treated by total surgical resection, which yields acceptable results with low rates of mortality and permanent morbidity.

Anterior and middle cranial fossa in traumatic brain injury: relevant neuroanatomy and neuropathology in the study of neuropsychological outcome.

The frontal and temporal lobe regions of the brain have a high vulnerability to injury as a consequence of cerebral trauma. One reason for this selective vulnerability is how the frontal and temporal regions are situated in the anterior and cranial fossa of the skull. These concavities of the skull base cup the frontal and temporal lobes which create surface areas of contact between the dura, brain, and skull where mechanical deformation injures the brain. In particular, the sphenoid ridge and the free-edge of the tentorium cerebelli are uniquely situated to facilitate injury to the posterior base of the frontal lobe and the anterior pole and medial surface area of the temporal lobe. Three-dimensional image reconstruction with computerized tomography and magnetic resonance imaging are used to demonstrate the vulnerability of these regions. How neuropsychological deficits result from damage to these areas is reviewed and discussed.

Huge primary myxoma of skull base: a report of an uncommon case.

We report a 27-year-old male who presented with paroxysmal headache, stuffy nose, epistaxis and impairment of vision in each eye. A huge chondrosarcoma, arising from the skull base with extension into the middle cranial fossa and nasal cavity was suspected. The patient underwent craniotomy and endoscope-assisted transnasal resection and a satisfactory removal was achieved. Postoperative immunohistochemical examination confirmed the diagnosis of myxoma rather than chondrosarcoma. The patient remained neurologically intact except for poor vision in the left eye at six-month follow-up. The relevant literature was reviewed and discussed. The main treatment of myxomas of cranial base is by surgery.

Garcin's syndrome--a case report.

BACKGROUND: Garcin's syndrome in its complete form is very rare, and hence, this case is reported. CASE DESCRIPTION: A 45-year-old patient presented to us with proptosis of the right eye and progressive weakness of all cranial nerves on the right side without associated features of raised intracranial pressure or long tract dysfunction. He had a bulge in the right buccolabial fold, from which fine needle aspiration cytology was done. Cytology report came as a poorly differentiated carcinoma. CONCLUSIONS: Garcin's syndrome is a very rare neurosurgical entity. The course of the condition depends on the nature of underlying pathology.

Middle and posterior fossa aspergilloma.

BACKGROUND: Aspergilloma of the brain is a rare disease. Among its varied presentations, a solitary intracranial mass is very uncommon. A preoperative diagnosis of it is very difficult, but a perioperative squash smear/frozen section can identify the pathology. Because of its rarity in immunocompetent patients and the difficulty in preoperative diagnosis, we have illustrated this case and its presentation and management. METHODS: A 27-year-old man presented with an h/o right-sided weakness along with headache and ear discharge. A computed tomographic (CT) scan showed a large irregular, space-occupying lesion in the middle and posterior cranial fossa. He had a mastoidectomy done 3 years before for chronic suppurative otitis media. After a symptom-free interval of 1 year, he was investigated for severe earache on the same side. A CT scan at that time showed a space occupying mass in the right temporal bone and right inferior temporal lobe. A biopsy and histopathology of the lesion revealed a chronic granulomatous mass. He was started on antituberculous drugs and was on it for 7 months at the time of presentation. RESULTS: He underwent a suboccipital craniectomy and total excision of the mass. Postoperatively, his consciousness improved but began to deteriorate on the third postoperative day. A repeat CT scan showed hydrocephalus and total removal of the mass. An external ventricular drain was put and he was ventilated, but he died on the fourth postoperative day. Histopathology report came as aspergilloma. CONCLUSION: This report highlights the rare presentation of aspergilloma in an immunocompetent patient. It emphasizes the importance of suspecting this disease in such patients and the role of intraoperative squash smear preparations or frozen section in the diagnosis as routine diagnostic procedures that will help in early pharmacotherapeutic interventions in adjunct to surgery.

Unusual locations for cavernous hemangiomas: report of two cases and review of the literature.

Cavernous hemangiomas are most commonly found within the subcortical neural parenchyma near the fissura Rolandi, in the basal ganglia, or in the brain stem. Because of advancing neuro-imaging technology and thus resulting in a higher incidence of cavernous hemangiomas they have rising impact in neurosurgery. We present two unusual cases of extra-axial cavernous hemangiomas: one located at the frontal falx, the other within the bone of the right frontal bone. We discuss these and other cases in the literature with respect to the more common differential diagnoses and the appropriate therapy regimen for cavernous hemangiomas in these locations.

Long-term hearing preservation after middle fossa removal of vestibular schwannoma.

OBJECTIVE: We sought to determine long-term hearing preservation in vestibular schwannoma patients after undergoing middle fossa resection. STUDY DESIGN, SETTING, AND OUTCOME MEASURES: We conducted a retrospective chart review of patients undergoing middle fossa resection from 1990 to 1995 at a tertiary care center. Pure-tone thresholds, before resection and at least 5 years after resection, and speech discrimination scores are reported. RESULTS: Seventy percent of patients with immediate postoperative hearing maintained serviceable hearing at more than 5 years after surgery. Pure-tone average in the operative ear changed at the same rate as hearing in the unoperated ear during this follow-up period. CONCLUSIONS: More than two thirds of patients who underwent middle fossa resection of a vestibular schwannoma with some hearing postoperatively maintain that hearing at greater than 5 years of follow-up. Surgery alone does not have a negative impact on long-term hearing preservation.