Acute neurological complications following gamma knife surgery for vestibular schwannoma. Case report

The authors describe an acute facial and acoustic neuropathy following gamma knife surgery (GKS) for vestibular schwannoma (VS). This 39-year-old woman presenting with tinnitus underwent GKS for a small right-sided intracanalicular VS, receiving a maximal dose of 26 Gy and a tumor margin dose of 13 Gy to the 50% isodose line. Thirty-six hours following treatment she presented with nausea, vomiting, vertigo, diminished hearing, and a House-Brackmann Grade III facial palsy. She was started on intravenous glucocorticosteroid agents, and over the course of 2 weeks her facial function returned to House-Brackmann Grade I. Unfortunately, her hearing loss persisted. A magnetic resonance (MR) image obtained at the time of initial deterioration demonstrated a significant decrease in tumor enhancement but no change in tumor size or peritumoral edema. Subsequently, the patient experienced severe hemifacial spasms, which persisted for a period of 3 weeks and then progressed to a House-Brackmann Grade V facial palsy. During the next 3 months, the patient was treated with steroids and in time her facial function and hearing returned to baseline levels. Results of MR imaging revealed transient enlargement (3 mm) of the tumor, which subsequently returned to its baseline size. This change corresponded to the tumor volume increase from 270 to 336 mm3. The patient remains radiologically and neurologically stable at 10 months posttreatment. This is the first detailed report of acute facial and vestibulocochlear neurotoxicity following GKS for VS that improved with time. In addition, MR imaging findings were indicative of early neurotoxic changes. A review of possible risk factors and explanations of causative mechanisms is provided.     

Facial Nerve Schwannomas of the Cerebellopontine Angle: The Mayo Clinic Experience

Background There is often controversy regarding the optimal management for patients with facial nerve schwannomas (FNSs) of the cerebellopontine angle (CPA).Methods The clinical and radiological outcomes in 14 patients with CPA FNS were retrospectively reviewed.Results Patients underwent resection with anatomic nerve preservation (n = 3), facial-hypoglossal nerve anastomosis (n = 4), gamma knife radiosurgery (GKS) (n = 6), or observation (n = 1). A total of 83% of tumors that underwent GKS were stable or decreased in size. No patient who underwent resection showed evidence of tumor recurrence; the tumor under observation remained unchanged with normal facial function at the time of the last follow-up. Facial function was decreased in 57%, stable in 14%, and improved in 29% of those who underwent microsurgery. A total of 67% of patients who underwent GKS had stable facial function. Serviceable hearing was maintained in 50% of patients in the GKS group and 67% of the tumor resection group. Mean and median follow-up was 48 and 43 months, respectively (range, 12 to 95 months).Conclusion Observation should be the primary management when encountered with FNS of the CPA in those with good neurologic function. Microsurgery or radiosurgery may be used in those with poor facial function or tumor progression.     

Contralateral hearing loss and facial palsy in an operated case of vestibular schwannoma—Case report

IntroductionContralateral ear hearing loss (CHL) is an extremely rare but a potentially devastating complication in a patient with already compromised hearing due to a Vestibular schwannoma (VS). Our patient had CHL accompanied by contralateral facial palsy. Our case is only the second case reported in literature to the best of our knowledge.Presentation of caseA 55-year elderly male presented with right sided sensorineural hearing loss, cerebellar signs and Grade II House & Brackmann (H&B) facial nerve weakness for last1-year. Magnetic resonance imaging (MRI) scan revealed a large right sided vestibular schwannoma (VS) with severe compression of the ipsilateral pons. The pre-operative pure tone audiometry (PTA) documented severe sensory neural hearing loss (SNHL) on the right side along with mild SNHL on the left side. A right retromastoid suboccipital craniotomy was performed and VS was completely excised. The ipsilateral facial nerve was preserved anatomically. On the 4th post-operative day he developed severe pain and tinnitus in left ear. In the next 24-h there were hearing loss and grade II facial nerve paresis. The PTA done on the 5th post-operative day revealed severe SNHL on both sides. He was managed conservatively with steroids and vasodilators. At 6-months of follow-up the left side hearing loss and facial weakness had significantly recovered. The PTA showed significant improvement in the left side SNHLDiscussionContralateral hearing disturbance with contralateral facial palsy after acoustic neuroma surgery is extremely rare. The exact etiopathogenesis of this unusual phenomenon is not clear and various theories have been proposed. There is no standard recommendation for treatment of these rare complications and the etiology remains obscure.ConclusionHearing loss and facial palsy on the contralateral side after VS surgery is extremely rare. It is imperative that this rare complication should be considered following VS surgery.     

Repeated treatment of vestibular schwannomas after gamma knife radiosurgery

Purpose  When gamma knife radiosurgery (GKS) does not achieve control of the growth of a tumour, the need to repeat treatment is considered. The results and risks of repeat treatment of patients with a vestibular schwannoma were reviewed to assess its efficacy and safety. Methods  Between 1992 and 2001, we treated 351 patients with a vestibular schwannoma by GKS, control of the growth of the tumour was not achieved in 32. 26 patients underwntrepeat GKS and five patients had an open microsurgical operation and one stereotactic aspiration of a tumour cyst. Results  Twenty-four of 26 patients were followed up after the repeat GKS for a median of 43 months. 15 tumours became smaller, seven remained unchanged and two enlarged. After the second GKS one patient’s hearing deteriorated, one developed facial weakness and three facial spasms. One patient required insertion of ventriculo-peritoneal drainage. An operation to radically resect the tumour was performed in five patients after the first GKS and for a subtotal removal in one after repeated GKS. Conclusions  In the small proportion of patients (9%) in whom initial GKS does not control the growth of a vestibular schwannoma, most can be controlled by further GKS with a very low risk of a complications.     

Immediate neurological deterioration after gamma knife radiosurgery for acoustic neuroma. Case report

The authors describe acute deterioration in facial and acoustic neuropathies following radiosurgery for acoustic neuromas. In May 1995, a 26-year-old man, who had no evidence of neurofibromatosis Type 2, was treated with gamma knife radiosurgery (GKS; maximum dose 20 Gy and margin dose 14 Gy) for a right-sided intracanalicular acoustic tumor. Two days after the treatment, he developed headache, vomiting, right-sided facial weakness, tinnitus, and right hearing loss. There was a deterioration of facial nerve function and hearing function from pretreatment values. The facial function worsened from House-Brackmann Grade 1 to 3. Hearing deteriorated from Grade 1 to 5. Magnetic resonance (MR) images, obtained at the same time revealed an obvious decrease in contrast enhancement of the tumor without any change in tumor size or peritumoral edema. Facial nerve function improved gradually and increased to House-Brackmann Grade 2 by 8 months post-GKS. The tumor has been unchanged in size for 5 years, and facial nerve function has also been maintained at Grade 2 with unchanged deafness. This is the first detailed report of immediate facial neuropathy after GKS for acoustic neuroma and MR imaging revealing early possibly toxic changes. Potential explanations for this phenomenon are presented.     

Transient facial nerve palsy after topical papaverine application during vestibular schwannoma surgery. Case report

Some evidence in the literature supports the topical application of papaverine to the cochlear nerve to prevent internal auditory artery vasospasm and cochlear ischemia as a method of enhancing the ability to preserve hearing during acoustic neuroma surgery. The authors report a case of transient facial nerve palsy that occurred after papaverine was topically applied during a hearing preservation acoustic neuroma removal. A 58-year-old woman presented with tinnitus and serviceable sensorineural hearing loss in her right ear (speech reception threshold 15 dB, speech discrimination score 100%). Magnetic resonance imaging demonstrated a 1.5-cm acoustic neuroma in the right cerebellopontine angle (CPA). A retrosigmoid approach was performed to achieve gross-total resection of the tumor. During tumor removal, a solution of 3% papaverine soaked in a Gelfoam pledget was placed over the cochlear nerve. Shortly thereafter, the quality of the facial nerve stimulation deteriorated markedly. Electrical stimulation of the facial nerve did not elicit a response at the level of the brainstem but was observed to elicit a robust response more peripherally. There were no changes in auditory brainstem responses. Immediately after surgery, the patient had a House-Brackmann Grade V facial palsy on the right side. After several hours, this improved to a Grade I. At the 1-month follow-up examination, the patient exhibited normal facial nerve function and stable hearing. Intracisternal papaverine may cause a transient facial nerve palsy by producing a temporary conduction block of the facial nerve. This adverse effect should be recognized when topical papaverine is used during CPA surgery.     

Meningioma of the internal auditory canal with rapidly progressive hearing loss: case report

A 38-year-old male presented with a meningioma within the internal auditory canal (IAC) manifesting as rapidly progressive hearing loss over a period of one month. He had a 2-year history of tinnitus. Magnetic resonance imaging revealed a 10-mm intracanalicular tumor, which was surgically resected by a retrosigmoid lateral suboccipital approach. The histological findings showed meningothelial meningioma. The patient had no facial palsy after surgery, but his cochlear function did not recover. Common symptoms of IAC meningiomas are tinnitus and hearing loss, but rapidly progressive hearing loss is very rare. IAC meningioma is rare but should be taken into consideration as a cause of rapidly progressive hearing loss.     

Huge facial nerve schwannoma extending into the middle cranial fossa without facial palsy: case report

The facial nerve schwannoma is a rare tumor and it seldom extends into the middle cranial fossa. The typical clinical presentations are progressive facial paralysis and hearing disturbance. We report here a case of huge facial nere facial nerve schwannoma extending into the middle cranial fossa without facial palsy. A 50-year-old man presented with left hearing disturbance. Neurological examination on admission revealed no deficits except for sensorineural hearing loss. MRI demonstrated a cystic tumor extending into the ddle cral fossa from the petrous bone CT the middle cranial fossa from the petrous bone. CT of the temporal bone showed destruction of the surrounding bone around the geniculate ganglion and invasion of the tumor into the tympanic cavity and internal auditory canal. The intracranial tumor was totally removed and the operative specimen demonstrated that the tumor was a schwannoma. The patient was discharged without neurological deficit. The facial nerve schwannoma extending into the middle cranial fossa without facial palsy is rare and only 4 cases have been reported in the literature. The tumor origin was in the greater superficial petrosal nerve and geniculate ganglion. The symptom is conductive hearing loss caused by the tumor extending into the tympanic cavity. We should bear in mind that there is a also rare type of facial nerve schwannoma manifesting hearing disturbance alone.     

Two cases of facial neurinoma successfully treated with gamma knife radiosurgery

Two cases of facial neurinoma successfully treated with gamma knife radiosurgery are reported. Case 1, a 33-year-old female, developed a right-sided hemifacial spasm about five years ago. Then she suffered gradual progression of right-sided facial palsy, dysgeusia and reduction of lacrimation, but she had no hearing disturbance. T1-weighted MRI with gadolinium DTPA showed a well-circumscribed tumor at the geniculate ganglion extending to the middle cranial fossa. The tumor was treated with gamma knife radiosurgery which reduced its size, but didn't reduce the patient's facial palsy. Case 2, a 36-year-old female, presented with fluctuating facial palsy and sensorineural hearing loss lasting for fourteen years. T1-weighted enhanced MRI showed a well-enhanced tumor at the CP angle extending to the middle cranial fossa. The tumor was treated with gamma knife radiosurgery, which caused central tumor necrosis, but didn't reduce the tumor size. Meanwhile the patient's facial palsy improved. Gamma knife radiosurgery is apparently effective against facial neurinomas without producing serious complications such as complete facial palsy and hearing loss. Our study indicates that gamma knife radiosurgery is a useful therapeutic alternative for facial neurinomas.     

Functional outcome after gamma knife surgery or microsurgery for vestibular schwannomas

OBJECT: Microsurgical excision is an established treatment for vestibular schwannoma (VS). In 1992 the authors used a patient questionnaire to evaluate the functional outcome and quality of life in a series of 224 consecutive patients. In addition, starting with gamma knife surgery (GKS) in 1992, the authors decided to use the same methodology to evaluate prospectively the results of this modality to compare the two alternatives. METHODS: Among the 500 patients who were included prospectively, the authors only evaluated patients in whom GKS was the primary treatment for unilateral VS. Four years of follow up was available for the first 104 consecutive patients. Statistical analysis of the GKS and microsurgery populations has shown that only a comparison of Stage II and III (according to the Koos classification) was meaningful in terms of group size and preoperative risk factor distribution. Objective results and questionnaire answers from the first 97 consecutive patients were compared with the 110 patients in the microsurgery group who fulfilled the inclusion criteria. Questionnaire answers indicated that 100% of patients who underwent GKS compared with 63% of patients who underwent microsurgery had no new facial motor disturbance. Forty-nine percent of patients who underwent GKS (17% in the microsurgery study) had no ocular symptoms, and 91% of patients treated with GKS (61% in the microsurgery study) had no functional deterioration after treatment. The mean hospitalization stay was 3 days after GKS and 23 days after microsurgery. All the patients who underwent GKS who had been employed, except one, had kept the same professional activity (56% in the microsurgery study). The mean time away from work was 7 days for GKS (130 days in the microsurgery study). Among patients whose preoperative hearing level was Class 1 according to the Gardner and Robertson scale, 70% preserved functional hearing after GKS (Class 1 or 2) compared with only 37.5% in the microsurgery group. CONCLUSIONS: Functional side effects happen during the first 2 years after radiosurgery. Findings after 4 years of follow up indicated that GKS provided better functional outcomes than microsurgery in this patient series.     

Episodic facial palsy due to epithelial cyst of the cerebellopontine angle: case report and review of the literature

A case of cerebellopontine angle epithelial cyst is described. Lesions in this region usually present with hearing loss, tinnitus, dysequilibrium, headaches, facial numbness and occasionally trigeminal neuralgia. Our patient presented with the unusual phenomenon of episodic facial palsy. The literature reporting this lesion as well as this mode of presentation has been reviewed.     

微血管减压术治疗面肌痉挛术后并发症分析

目的探讨微血管减压术（microvascular decompression,MVD）治疗面肌痉挛术后并发症原因及处理。方法对2000年12月～2007年3月我院207例面肌痉挛行MVD术后进行1年以上的随访,观察相关并发症的发生及恢复情况。结果无一例死亡,15例（7.2%）在术后1周内出现脑脊液漏皮下积液,给予加压包扎（13例）,穿刺抽吸后加压包扎并头高脚低位（2例）处理后出院时积液基本消失,48例（23.2%）出现面瘫,20例（9.7%）出现听力下降,12例（5.8%）出现耳鸣。术后随访1～7.3年,（4.2±2.7）年,无一例发生脑脊液漏及颅内感染,面瘫及耳鸣患者全部恢复,10例（4.8%）仍有听力障碍,其中6例（2.9%）为耳聋。结论脑脊液漏、皮下积液、面瘫、耳鸣、听力下降是MVD的主要并发症,脑脊液漏、皮下积液、面瘫、耳鸣可逆转,听力障碍是远期主要的并发症,术中注重操作技巧可减少并发症的发生。     

Facial nerve schwannomas: different manifestations and outcomes

BACKGROUND: The purpose of this study was to provide data on the different clinical presentations of facial nerve schwannoma, the appropriate planning for the management of schwannoma of various origins, and the predictive outcomes of surgical management. METHODS: A retrospective study was conducted in a tertiary referral hospital. We reviewed 8 consecutive cases of facial nerve schwannoma diagnosed and managed between 1993 and 2001. RESULTS: Facial nerve schwannomas originated in the internal auditory canal (IAC) (2 cases), parotid gland (2 cases), intratemporal portion (3 cases), and stylomastoid foramen (1 case). Tumor of the stylomastoid foramen presented as an intra- and extratemporal mass. The initial presenting symptom of the 8 patients was facial nerve paralysis in 4 patients, hearing loss in 2, facial numbness in 1, and an infra-auricular mass in 1. Facial palsy occurred in 7 patients during the course of the disease. One patient with a mass in the parotid gland did not show facial palsy up to 1 year after presentation of the initial symptom (facial numbness). Facial nerve paralysis was most severe in intratemporal tumors and less severe in parotid tumors. The patients with IAC suffered from hearing loss and intermittent vertigo and showed decreased vestibular function. The patients with intratemporal tumors also complained of hearing loss. The tumors were completely removed by superficial parotidectomy for parotid tumors; the translabyrinthine approach for 1 IAC tumor and 1 intratemporal tumor; the middle fossa approach for the other IAC tumor; the transmastoid approach for mastoid tumors; and the infratemporal fossa approach for intratemporal and extratemporal tumors. End-to-end cable grafts for the facial nerve were performed in 5 out of 8 cases. In 2 cases, the facial nerve was preserved after the resection of the mass. One case showed complete loss of the peripheral branch of the facial nerve. CONCLUSIONS: Facial nerve schwannoma can present in various ways. By examining the site of origin and the presenting symptoms and signs, we were able to diagnose facial nerve schwannoma preoperatively. According to the operative management of the facial nerve, the postoperative outcome of facial function could be estimated. Our finding could be pivotal in the management of the facial nerve schwannoma.     

Irradiation of cochlear structures during vestibular schwannoma radiosurgery and associated hearing outcome

OBJECT: The purpose of this study was to measure the dose of radiation delivered to the cochlea during a Gamma knife surgery (GKS) procedure for treatment of patients with vestibular schwannomas (VSs), and to analyze the relationship between cochlear irradiation and the hearing outcome of these patients. METHODS: Eighty-two patients with VSs were treated with GKS using a marginal dose of 12 Gy. No patient had neurofibromatosis Type 2 disease, and all had a Gardner-Robertson hearing class of I to IV before treatment, and a radiological and audiological follow-up of at least 1-year after GKS. The dosimetric data of the volume of the cochlea were retrospectively analyzed and were correlated with the auditory outcome of patients. RESULTS: The mean radiation dose delivered to the cochlear volume ranged from 1.30 to 10.00 Gy (median 4.15 Gy). The cochlea received significantly higher radiation doses in patients with worsening of hearing after GKS. A highly significant association between the cochlear and the intracanalicular dose of radiation delivered during GKS was found. CONCLUSIONS: During GKS for VSs, relatively high doses of radiation can be delivered to the cochlea. Worsening of hearing after GKS can be the consequence of either radiation injury to the cochlea or the irradiation dose delivered into the auditory canal, or both.     

Two cases of the epidermoid on the petrous bone

Epidermoids known as cholesteatomas, are congenital benign tumors and originate in the embryonic ectoderm. They account for 1.3% of all intracranial tumors. They are often found in the cerebellopontine angle and the paraseller region, but rarely in the petrous portion of the temporal bone. Epidermoids of the petrous bone tend to slowly present progressive facial palsy and hearing disturbance. In this article, two cases of epidermoids involving the petrous bone are reported. A 55-year-old male presented left facial palsy, left hearing disturbance and decreased gustation in the left side of the tongue. MRI revealed a non-enhanced mass on the petrous portion of the left temporal bone, and bone-window CT showed bone destruction in the same region (Case 1). A 71-year-old female was aware of left facial palsy and left hearing loss for 15 years. MRI showed a non-enhanced mass on the petrous bone, and bone-window CT demonstrated extensive bone erosion of the petrous bone and the middle cranial fossa (Case 2). In both cases, total removal was performed via the middle cranial fossa approach. Both tumors existed extradurally and had pressed against the genicurate ganglion of the facial nerve. The facial palsy of the former case recovered 12 months after surgery. We discuss the problems of diagnosis and treatment of epidermoids of the petrous bone.     

A case of crushing head injury showing bilateral abducens, facial and acoustic nerve palsies

Most head injuries are due to two basic mechanisms, contact or acceleration. On the other hand, static loading force makes another type of head injury, so called "crushing head injury". In this report, we discussed the mechanism of the crushing head injury and cranial nerve damage of our case. A 35-year-old male was admitted to our hospital suffering from a crushing head injury. In this accident, his head had been crushed between 1000-kg printing machine and truck bed on both temporal regions slowly. He remained fully conscious. On admission 25 minutes after the injury, he showed bilateral sixth-nerve, seventh-nerve palsies, bilateral hearing loss and obvious bleeding from nares and both ears. Gross motor examination was intact. Skull films demonstrated left temporal linear fracture. CT scan showed remarkable pneumocephalus in the basal cistern but no other intracranial lesions. At discharge, two weeks after the trauma, the patient was alert and remained bilateral sixth-nerve, seventh-nerve palsies, and bilateral hearing loss. At the time of 6 months after the initial injury, bilateral abducens nerve palsies and left facial nerve palsy were improved completely. But he demonstrated right slight facial nerve palsy and bilateral moderate hearing loss continuously. In this rare type of injury, the head of the patients had been crushed slowly by the huge power on both temporal regions. This force makes the avulsion of the petrous bone from the foramen lacerun to the outer side of the bone (Russell WR and Schiller F, 1949). This must tend to stretch the sixth nerve and produce abducens nerve injury.(ABSTRACT TRUNCATED AT 250 WORDS)     

Large facial nerve schwannomas without facial palsy: case reports and review of the literature

Although approximately 30% of facial nerve schwannoma cases present with no facial palsy, a large facial nerve schwannoma extending to the middle and posterior cranial fossa quite rarely presents without facial palsy. The authors encountered two patients with large facial nerve schwannoma who presented with only hearing impairment and no facial palsy. The first patient was a 64-year-old woman who presented with right auditory impairment without facial palsy. MR images demonstrated a dumbbell-shaped tumor in the cerebellopontine angle. Another patient, a 40-year-old woman, also presented with vertigo and right tinnitus without facial palsy. MR images demonstrated a huge tumor expanding into both the posterior cranial fossa and middle cranial fossa. In both cases, intraoperative findings confirmed that the tumors had grown from the facial nerve. Facial nerve schwannoma can be easily diagnosed if detailed neurological evaluations and appropriate neuroimagings are conducted. However, in spite of such huge tumoral size and expanding pattern, the facial nerve function was relatively preserved. Anatomical features of the facial schwannoma are discussed. A tumor extending to the middle and posterior cranial fossa should remind neurosurgeons to consider facial nerve schwannomas even in the absence of facial palsy.     

Spontaneous disappearance of cerebellopontine angle arachnoid cyst: report of a case

A case of a cerebellopontine angle arachnoid cyst spontaneously disappeared is reported. A 1-year-and-11-month old boy was suffered from sudden onset of left facial palsy. CT scan demonstrated dilatation of left internal auditory canal and a cystic lesion in the left cerebellopontine angle. Neurological examination disclosed only left facial palsy and left hearing loss. There was no signs and symptoms of increased intracranial pressure. He was followed up by CT scan. Repeated CT scan showed non-enhanced cystic lesion, the attenuation value of which was similar to that of cerebrospinal fluid. The cyst expanded gradually, and the brain stem was severely compressed. Then operation was planned under the diagnosis of left cerebellopontine angle arachnoid cyst about 2 years after the onset. But CT scan performed before operation showed disappearance of the cyst. Without operation the patient was followed by CT scan. There is no recurrence of the cyst. Natural history of arachnoid cyst will be well understood with repeated CT scan.     

Facial Nerve Neuroma: Surgical Concept and Functional Results

This study reviewed the management and outcomes of 11 facial nerve neuromas treated in our institution during the past two decades with particular emphasis on surgical concepts and functional outcomes. All patients underwent complete surgical resection of their tumor. Eight patients (73%) were followed on an outpatient basis. A retrospective chart review for pre- and postoperative clinical and radiological data was performed. All facial neuromas were multi-segment tumors. All segments of the facial nerve were represented, but 54% involved the geniculate ganglion and 45% involved the labyrinthine or tympanic portions of the nerve, or both. Depending on the extent of sensorineural hearing loss, surgical removal was performed through the middle cranial fossa or translabyrinthine approach. To obtain adequate nerve reconstruction, we combined intra- and extracranial approaches (e.g., the transmastoidal and transtemporal routes). Regardless of the type of nerve reconstruction, the best recovery achieved was moderate facial weakness (House-Brackmann Grade III) in 75% of the patients, even in a patient who was Grade IV preoperatively. The choice of treatment for facial neuromas and surgical approach depends on the extent of tumor, grade of facial palsy, and hearing function. When facial palsy is present, complete resection is clearly indicated. In patients without facial dysfunction, a conservative strategy consisting of clinical and radiological observation should be considered as a treatment option.