Conservative management of vestibular schwannomas – second review of a prospective longitudinal study

Vestibular schwannomas have been traditionally managed with microsurgical removal and in recent years, stereotactic radiotherapy. However, there is a group of patients in whom a conservative management approach might represent a desirable alternative. The aim of this study was to determine the natural history and outcome following the conservative management of 72 patients with unilateral vestibular schwannomas. This is a prospective cohort review of a previously published group of patients [Clin. Otolaryngol. (2000) 25 , 28–39] with unilateral vestibular schwannoma that were initially analysed at our institution in 1998 [Walsh R.M., Bath A.P., Bance M.L. et al., Clin. Otolaryngol. (2000) 25 , 28]. The mean duration of follow‐up was 80 months (range 52–242 months). All the patients in the study underwent serial magnetic resonance imaging (MRI) for assessment of tumour growth. Patients were deemed to have failed conservative management if there was evidence of rapid radiological tumour growth and/or increasing signs and symptoms, which necessitated active intervention. The mean tumour growth rate for the entire group at the second review was 1 mm/year (range ?0.84–9.65 mm/year). The mean growth rate for cerebellopontine angle tumours (1.3 mm/year) was significantly greater than that of internal auditory canal (IAC) tumours (0 mm/year) (P = 0.005). The majority of tumours (87.14%) grew <2 mm/year. There was significant tumour growth seen in 38.9%, no or insignificant growth in 41.7%, and negative growth in 19.4%. Twenty‐three patients (32%) failed conservative management at the second review. There was no difference in the outcome of these failed patients in comparison with patients who underwent primary treatment without a period of conservative management. The mean growth rate of tumours in patients that failed conservative management (3.1 mm/year) was significantly greater than that in patients who did not fail (0.2 mm/year) (P < 0.001). No factors predictive of tumour growth or failure of conservative management were identified. Hearing deterioration with pure tone averages (0.5, 1, 2, 3 kHz) and speech discrimination scores occurred irrespective of tumour growth. This prospective study further emphasizes the role of conservative management in selected cases of vestibular schwannomas. Tumours in this study confined to the IAC typically demonstrated minimal or no growth on serial MRI scanning. Regular follow‐up with interval scanning is mandatory in all patients.     

The natural history of untreated vestibular schwannomas. Is there a role for conservative management?

OBJECTIVE: The aim of this study was to investigate the natural history and outcome following the conservative management of a group of patients with unilateral vestibular schwannomas. METHODS: 72 patients with a radiological diagnosis of unilateral vestibular schwannoma were managed conservatively because of poor general health, advanced age, patient preference, small tumour size, minimal symptoms, or tumour in the only/better hearing ear. All patients underwent serial magnetic resonance imaging for assessment of tumour growth, according to American Academy of Otolaryngology-Head & Neck Surgery guidelines (1995). The mean duration of follow-up was 37.8 months (range 12-194 months). Patients were deemed to have failed conservative management if there was evidence of continuous or rapid radiological tumour growth, and/or increasing symptoms or signs. RESULTS: The mean tumour growth rate was 1.16 mm/year (range -0.75 to 9.65 mm/year). Approximately 83% of tumours grew at less than 2 mm/year. Significant tumour growth (total growth > 1 mm) was seen in 36.4%, no or insignificant growth (0-1 mm) in 50%, and negative growth (< 0 mm) in 13.6% of tumours. The growth rate of cerebellopontine angle (CPA) tumours (1.4 mm/year) was significantly greater than that of tumours limited to the internal auditory canal (IAC) (0.2 mm/year) (p = 0.001). Failure of conservative management, in which active treatment was required, occurred in 15.3%. The outcome of these patients appeared to be as favourable as those who underwent primary treatment, without a period of conservative management. The growth rate of tumours in patients who failed conservative management (4.2 mm/year) was significantly greater than that in patients who did not fail (0.5 mm/year) (p < 0.01). No factors predictive of tumour growth were identified. Deterioration of mean pure tone average (0.5, 1, 2, 3 kHz) and speech discrimination scores occurred regardless of whether radiological tumour growth was demonstrated or not. CONCLUSIONS: The majority of vestibular schwannomas are slow growing, although, CPA tumours appear to grow faster than IAC tumours. Deterioration of auditory function occurs even in the absence of tumour growth. Although most Otolaryngologists and Neurosurgeons would agree that the treatment of choice for the majority of vestibular schwannomas is microsurgery, there remains a small group of patients in whom a conservative management approach may be a desirable alternative.     

The role of conservative management of vestibular schwannomas

Although microsurgery is generally regarded as the conventional treatment of choice for most vestibular schwannomas, there remains a group of patients in whom a conservative management approach may be a desirable alternative. The aim of this study was to determine the natural history and outcome following the conservative management of 72 patients with unilateral vestibular schwannomas. The reasons for conservative management included poor general health, age, patient preference, small tumour size, minimal or no symptoms, and tumour in the only/better hearing ear. The mean duration of follow-up was 39.8 months (range 12-194 months). All patients underwent serial magnetic resonance imaging (MRI) for assessment of tumour growth. Patients were deemed to have failed conservative management if there was evidence of continuous or rapid radiological tumour growth and/or increasing symptoms or signs. The mean tumour growth rate, according to the 1995 guidelines of the American Academy of Otolaryngology/Head and Neck Surgery, was 1.16 mm/year (range: 0.75 9.65 mm/year). Approximately 83% of tumours grew at < 2 mm/year. Significant tumour growth was seen in 36.4%, no or insignificant growth in 50%, and negative growth in 13.6% of tumours. The growth rate of CPA tumours (1.4 mm/year) was significantly greater than that of IAC tumours (0.2 mm/year) (P = 0.001). Failure of conservative management, in which active treatment was required, occurred in 15.3%. The outcome of these patients appeared to be as favourable to a comparable group who underwent primary treatment, without a period of conservative management. The mean growth rate of tumours in patients who failed conservative management (4.2 mm/year) was significantly greater than that in patients who did not fail (0.5 mm/year) (P < 0.01). No factors predictive of tumour growth or failure of conservative management were identified. Deterioration of mean pure tone average (0.5, 1, 2, 3 kHz) and speech discrimination scores occurred regardless of whether radiological tumour growth was demonstrated or not. This study suggests that in a select number of cases of vestibular schwannoma, a conservative management approach may be appropriate. Regular follow-up with serial MRI is mandatory. Deterioration of auditory function occurs even in the absence of tumour growth.     

Investigations into the natural history of vestibular schwannomas

In the period from 1977 to 1996 143 vestibular schwannomas were diagnosed in 138 patients in the County of Aarhus, Denmark. The natural history of vestibular schwannomas was observed in 50 patients with 52 tumours who did not undergo immediate surgical removal of their tumour due to small tumour size, advanced age, poor general health and the patients' refusal of surgery. The management included serial CT- or MR-imaging and complete otoneurological evaluation. The imaging interval was between 6 months and 2 years and depended on the recorded growth rate. Thirty-three (64%) of the tumours showed continuous growth with a mean growth rate of 1.6 mm/year. In 11 (21%) of the tumours the size was unchanged and eight (15%) remitted. The last group consisted mainly of the largest tumours. Among the tumours with positive growth, 15 (45%) had a growth rate of 1 mm/year or less. Generally, our findings showed that approximately two-thirds of all the tumours did not grow, were getting smaller or had a growth rate sufficiently small to be simply watched. Additionally, our results suggest that some symptomatic tumours will grow to a certain point whereupon stagnation or remission occurs.     

Conservative management of vestibular schwannomas: third review of a 10‐year prospective study

• ? Seventy‐two patients with a unilateral vestibular schwannoma have been treated conservatively for a median of 121 months. They have been followed prospectively by serial clinical examination, MRI scans and audiometry.
• ? Twenty‐five patients (35%, 95% CI: 24–47) failed conservative management and required active intervention during the study. No factors predictive of tumour growth or failure of conservative management could be identified. Seventy‐five per cent of failures occurred in the first half of the 10‐year study.
• ? The median growth rate for all tumours at 10 years was 1 mm/year (range ?0.53–7.84). Cerebellopontine angle tumours grew faster (1.4 mm/year) than intracanalicular tumours (0 mm/year, P < 0.01); 92% had growth rates under 2 mm/year.
• ? Hearing deteriorated substantially even in tumours that did not grow, but did so faster in tumours that grew significantly (mean deterioration in pure tone average at 0.5, 1, 2 and 3 kHz was 36 dB; speech discrimination scores deteriorated by 40%).
• ? Patients who failed conservative management had clinical outcomes that were not different from those who underwent primary treatment without a period of conservative management.

     

Manejo conservador del schwannoma vestibular

IntroductionVestibular schwannoma (VS) is a benign, slow-growing tumour originating in the 8 th cranial nerve. The treatment includes microsurgery, stereotactic radiotherapy and conservative management of tumours with periodic radiological tests.MethodsThis was a retrospective study of patients with VS following conservative management in a tertiary hospital between 1993 and 2013. A total of 73 patients were enrolled in our protocol. The mean age at diagnosis was 59.7 years. The average size was 11.9 mm (4-27 mm); 58.9% of the tumours were intracanalicular and 41.1%, extracanalicular. The mean follow-up period was 35.75 months.ResultsIn 87.7% of patients there was no evidence of tumour growth. A total of 9 tumours (12.3%) increased in size. The average growth rate was 0.62 mm/year. The percentage of extracanalicular tumours that grew (20%) was higher than that of intracanalicular tumours (7%). Seven patients (9.5%) experienced significant changes in their symptoms and 6 of these (8.2%) experienced a loss of useful hearing. Six patients (8.2%) left follow-up and underwent surgery.ConclusionsPeriodic monitoring of vestibular schwannomas with magnetic resonance imaging represents an option for management, because most small tumours experience little or no growth over time.     

Growth rate of non‐vestibular intracranial schwannomas

Growth rate of non‐vestibular intracranial schwannomas A group of nine patients with non‐vestibular intracranial neuromas (four jugular, four facial, one trigeminal) underwent an interval scanning management policy, with serial annual magnetic resonance (MR) imaging. Tumour volume was assessed by manual measurement of the tumour area by MR imaging. Tumour volume was assessed by manual measurement of the tumour area on MR imaging axial cuts. The mean tumour size at presentation was 4.6 cm³ (range 0.7–17.8 cm³). During a mean follow‐up of 36 months (range 22–50 months), five out of nine tumours grew significantly at a rate of more than 5% of their initial volume per year. Only those tumours growing at a rate of more than 20% initial volume per year exhibited symptom progression. During a 36‐month period of interval scanning, just over 50% of non‐vestibular intracranial neuromas exhibited significant growth. Symptom progression was found to be a strong indicator of a high growth rate. This proportion exhibiting growth is higher than that demonstrated by unilateral sporadic vestibular schwannomas, but less than in patients with neurofibromatosis II. Early treatment of non‐vestibular intracranial neuromas should therefore be considered.     

Transapical extension in difficult cerebellopontine angle tumours: preliminary report

Difficult cerebellopontine angle (CPA) tumours namely large/giant vestibular schwannomas, vestibular schwannomas with a significant anterior extension and meningiomas of the posterior surface of the petrous bone extending anterior to the internal auditory canal (IAC) have always posed a problem for the otoneurosurgeon. Modifications of the enlarged translabyrinthine approach (ETLA) specifically aimed at dealing with these tumours are not reported. The aim of this paper is to introduce the transapical extension of ETLA which involves increased circumferential drilling around the IAC beyond 270 degrees C. The extension allows enhanced surgical control over the tumour as well as the anterior aspect of the CPA including the prepontine cistern, the Vth and VIth cranial nerves. The extension is further classified into Type I and II depending upon the extent of drilling. Type I extension entails drilling around the IAC for 300-320 degrees and is indicated for large/giant vestibular schwannomas (large vestibular schwannoma extrameatal diameter 3-39 cm, giant vestibular schwannoma extrameatal diameter >or=4 cm) and vestibular schwannomas with significant anterior extension. Type II extension involves complete drilling around the canal for 360 degrees and is indicated for meningiomas of the posterior surface of the petrous bone extending anterior to the IAC.     

Is clinical growth index a reliable predictor of tumour growth in vestibular schwannomas?

Is clinical growth index a reliable predictor of tumour growth in vestibular schwannomas? We have assessed the clinical growth index as an indicator of tumour growth rate in 50 patients with a vestibular schwannoma. Clinical growth index was calculated by measuring the length of history and dividing it by the maximum tumour diameter. Total tumour volumes were also measured from all MRI examinations and an effective tumour volume doubling time was calculated. Radiological growth measurements demonstrated involution in 10/50 patients. The median volume doubling time was 1.65 years (range 20.9‐46.3 months, skewness 1.72 years). The median clinical growth index was 0.030 cm per month (range 0‐0.270 cm per month, skewness 2.398). There was no significant correlation between volume doubling time and clinical growth index. Identification of rapidly growing tumours with clinical growth index >0.025 cm/month had a positive predictive value of 61%, negative predictive value of 48%, false‐positive rate of 30% and false‐negative rate of 52%. In conclusion, we have shown that the growth rate of vestibular schwannoma is not related to the clinical growth index and we recommend that this measure should be abandoned in the clinical management of patients where conservative management regimes are being considered.     

Management of intrameatal vestibular schwannoma

The growth of purely intrameatal vestibular schwannoma (VS) was investigated, in the period 1973-96 in a series of 40 patients with 40 unilateral VS. In the present study, the material was analysed and updated. By the end of the observation period (mean 3.6 years), 27 tumours (67.5%) revealed growth and 13 tumours (32%) had no measurable growth. Four growth patterns were observed: (A) 15 tumours (37.5%) exhibited constant growth; (B) 13 tumours (32.5%) had no measurable growth; (C) 8 tumours (20%) revealed growth subsequent to a no-growth period; and (D) 4 tumours (10%) showed different growth patterns during the observation period. The annual diameter growth rate ranged between 00 mm/year and 6.5 mm/year and the mean diameter growth per year was 3.2 mm. The findings of the present study, especially those for group B (the non-growing tumours) and C (tumour growth subsequent to a silent period) bring into question the reliability of the results achieved by radiosurgery, as without any intervention it may be that no tumour growth occurs.     

Growth rate of non-vestibular intracranial schwannomas

A group of nine patients with non-vestibular intracranial neuromas (four jugular, four facial, one trigeminal) underwent an interval scanning management policy, with serial annual magnetic resonance (MR) imaging. Tumour volume was assessed by manual measurement of the tumour area by MR imaging. Tumour volume was assessed by manual measurement of the tumour area on MR imaging axial cuts. The mean tumour size at presentation was 4.6 cm(3) (range 0.7-17.8 cm(3)). During a mean follow-up of 36 months (range 22-50 months), five out of nine tumours grew significantly at a rate of more than 5% of their initial volume per year. Only those tumours growing at a rate of more than 20% initial volume per year exhibited symptom progression. During a 36-month period of interval scanning, just over 50% of non-vestibular intracranial neuromas exhibited significant growth. Symptom progression was found to be a strong indicator of a high growth rate. This proportion exhibiting growth is higher than that demonstrated by unilateral sporadic vestibular schwannomas, but less than in patients with neurofibromatosis II. Early treatment of non-vestibular intracranial neuromas should therefore be considered.     

Management of growing vestibular schwannomas

Conservative management of small vestibular schwannomas is frequently proposed as most tumours do not grow. Anyway, tumour growth is reported in 30–40 % of the cases, so that surgery is consequently generally proposed. We primarily observed 161 patients affected by unilateral vestibular schwannomas. All patients were examined by means of gadolinium-enhanced magnetic resonance imaging scans. Tumour growth was recorded in 58 cases (35.8 %) and these subjects set up the group of study. Twenty-two (37.9 %) patients were surgically treated; tumour was always completely removed, all patients had normal facial function after surgery and only one patient suffered from a major complication (cerebellar haematoma). Fourteen patients (24.1 %) were submitted to radiotherapy, while one patient was lost at follow-up and another one died because of other medical reasons. Finally, 20 (34.5 %) subjects continued to be observed for different reasons. The mean follow-up period after identification of growth was 6.1 years. Nine tumours continued to grow, nine tumours stopped growing, one tumour grew and then regressed in size and one tumour decreased. Sixty percent of patients with useful hearing at diagnosis preserved it during the entire observation period. In conclusion, most of VS do not grow; in case of tumour growth, a surgical procedure may be suggested and the outcomes are not negatively influenced by the delay of the procedure. But in some cases, patients can still follow the “wait and scan” policy. In fact, only less than half of the growing tumours continued to grow. Moreover, most of the patients continued to retain a useful hearing.     

Sublocalization and volumetric growth pattern of intracanalicular vestibular schwannomas

OBJECTIVE: None of several previous reports on the growth pattern of vestibular schwannomas (VS) have dealt with the sublocalization and volumetric growth pattern of intracanalicular tumors. This paper reports such data from 196 patients. STUDY DESIGN: All VS patients have been registered prospectively at one center in Denmark since 1975. Data on intracanalicular tumors were drawn from the database, yielding 196 patients with a diagnostic and at least one control magnetic resonance imaging scan. All images were retrieved and the tumor sublocalization, size, and growth rate determined. RESULTS: The majority (50%) of the tumors was located centrally in the internal auditory canal (IAC), whereas 31% were porus-near and 19% fundus-near. Of the 196 tumors, 88 (45%) displayed growth, 20 (10%) shrinkage, and 88 (45%) remained unchanged. Thirty-eight (19%) tumors grew to extrameatal extension. Growth occurred only within 5 years after diagnosis. In the 88 growing tumors, the mean absolute growth rate was 111mm/year and the relative rate 114%/volume/year. The occurrence of IAC expansion at diagnosis was higher for tumors displaying subsequent shrinkage. Growth occurrence and rate, IAC expansion, and progression to extrameatal extension were not related to tumor sublocalization. CONCLUSION: Most intracanalicular VS are located centrally in a nonexpanded IAC at diagnosis. Growth occurs within 5 years after diagnosis in up to 45% of the tumors, although only 19% extend into the cerebellopontine angle. IAC expansion, growth occurrence, and rate are not related to tumor sublocalization. These findings justify primary observation of all purely intracanalicular tumors, unless realistic hearing preservation is intended.     

Cystic vestibular schwannoma: surgical outcome

We investigated the proportion of the cystic form of vestibular schwannoma and assessed the results of surgery in this subtype of the condition. The definition of cystic vestibular schwannomas was based on the following criteria: per-operative identification of cystic components; occurrence of the hypodense/hypointense areas on computed tomography (CT) and/or magnetic resonance (MR); and histological verification of S-100 protein membrane-like structures. In a study of 773 Danish patients with vestibular schwannomas, 44 (5.7 per cent) displayed cystic components. The outcome of surgery on 44 cystic vestibular schwannoma (mean tumour size 39 mm) was evaluated and compared with that for 151 solid grant vestibular schwannoma (mean tumour size 49.8 mm). Per-operatively, we found a substantially higher adherence to different intracranial structures in the solid giant vestibular schwannoma compared with the cystic vestibular (95 per cent vs 70 per cent for brainstem, 91 per cent vs 59 per cent for trigeminal nerve, 85 per cent vs 45 per cent for cranial nerves X and XI, 67 per cent vs 32 per cent for dura). Nevertheless, the preservation of the facial nerve function was much better in patients with solid giant vestibular schwannoma compared with those with cystic vestibular schwannoma (House-Brackmann facial nerve dysfunction grade 6 (one year post-operative): 27 per cent vs 41 per cent, respectively p < 0.04). We conclude that the cystic components in vestibular schwannoma are associated with a less favourable surgical outcome, probably due to the rapid tumour growth and symptoms caused by compression of the posterior fossa structures.     

Consequences to Hearing During the Conservative Management of Vestibular Schwannomas

Objective: To estimate the risk of loss of serviceable hearing during the conservative management of vestibular schwannomas. Study Design: Retrospective case review. Methods: Twenty‐five patients with a radiological diagnosis of unilateral vestibular schwannoma were managed conservatively for a mean duration of 43.8 months (range, 12–194 mo). The pure‐tone average (PTA) (0.5, 1, 2, and 3 kHz) and speech discrimination scores (SDS) were measured at regular intervals throughout the entire duration of follow‐up. Serviceable hearing was defined using two criteria: 70% SDS/30 dB PTA (the 70/30 rule) and 50% SDS/50 dB PTA (the 50/50 rule). The size and growth rate of tumors were determined according to the American Academy of Otolaryngology—Head and Neck Surgery guidelines (1995). Intervention was recommended if there was evidence of continuous or rapid radiological tumor growth, and/or increasing symptoms or signs suggestive of tumor growth. Results: The risk of loss of serviceable hearing for the total group was 43% using the 70/30 rule and 42% using the 50/50 rule. Tumor growth was considered significant (> 1 mm) in 8 tumors (32%) and nonsignificant in 17 (68%). The risk of loss of serviceable hearing for the tumor‐growth group was 67% using the 70/30 rule and 80% using the 50/50 rule. In contrast, the risk of loss of serviceable hearing for the no tumor–growth group was 25% using the 70/30 rule and 14% using the 50/50 rule. No audiological factors predictive of tumor growth were identified. Conclusions: There is a significant risk of loss of serviceable hearing during the conservative management of vestibular schwannomas. This risk appears to be greater in tumors that demonstrate significant growth.     

Is clinical growth index a reliable predictor of tumour growth in vestibular schwannomas?

We have assessed the clinical growth index as an indicator of tumour growth rate in 50 patients with a vestibular schwannoma. Clinical growth index was calculated by measuring the length of history and dividing it by the maximum tumour diameter. Total tumour volumes were also measured from all MRI examinations and an effective tumour volume doubling time was calculated. Radiological growth measurements demonstrated involution in 10/50 patients. The median volume doubling time was 1.65 years (range 20.9-46.3 months, skewness 1.72 years). The median clinical growth index was 0.030 cm per month (range 0-0.270 cm per month, skewness 2.398). There was no significant correlation between volume doubling time and clinical growth index. Identification of rapidly growing tumours with clinical growth index >0.025 cm/month had a positive predictive value of 61%, negative predictive value of 48%, false-positive rate of 30% and false-negative rate of 52%. In conclusion, we have shown that the growth rate of vestibular schwannoma is not related to the clinical growth index and we recommend that this measure should be abandoned in the clinical management of patients where conservative management regimes are being considered.     

Vestibular schwannoma growth rates in neurofibromatosis type 2 natural history consortium subjects.

OBJECTIVE: To determine the amount of growth in vestibular schwannomas in Neurofibromatosis type 2 (NF2) patients from diagnosis through short-term (up to 2 yr) and long-term (up to 4 yr) follow-up. STUDY DESIGN: Retrospective magnetic resonance imaging (MRI) films were obtained on subjects enrolled in the NF2 Natural History study and examined for changes in vestibular schwannoma size over time. SETTING: Data were collected from nine foreign and domestic NF2 centers, including hospital-based, academic, and tertiary care centers. SUBJECTS: NF2 patients with MRI data and at least one follow-up examination within 9 months to 2 years of diagnosis were included; n=56 patients with 84 lesions for evaluation of growth. INTERVENTION: Routine, clinically obtained, magnetic resonance images were digitized and measured using image management software. Short-term follow-up was defined as up to 2 years (n=84 lesions), and long-term follow-up was defined as 3 to 4 years (n=29 lesions). OUTCOME MEASURES: Vestibular schwannoma size was assessed using anterior-posterior, medial-lateral, and greatest diameter linear measurements. RESULTS: Vestibular schwannomas increased in size (at least 5 mm) in 8% of the vestibular schwannomas across short-term follow-up. At long-term follow-up, 13% of the tumors had increased in size. On average, schwannomas increased in greatest diameter 1.3 mm per year across short-term follow-up. CONCLUSION: Slightly greater than 1 in 10 diagnosed NF2-related vestibular schwannomas increased in size by at least 5 mm by 4 years of follow-up, if still untreated at that time.     

Hearing preservation in conservation surgery for vestibular schwannoma

OBJECTIVE: To evaluate preservation of hearing in the resection of vestibular schwannomas. STUDY DESIGN: A retrospective case review. SETTING: Tertiary-care medical center. PATIENTS: Forty-seven patients (25 men, 22 women) were studied; mean age was 46 years, mean tumor diameter 9.8 mm (range 3-30 mm.) INTERVENTIONS: All patients underwent resection of vestibular schwannomas by the middle cranial fossa (MCF) or the retrosigmoid (RS) approach. MAIN OUTCOME MEASURES: Hearing preservation was classified by the criteria outlined by the American Academy of Otolaryngology-Head Neck Surgery. Hearing was assessed preoperatively and postoperatively at 1 month and 1 year. Facial function was graded according to the House-Brackmann scale. Minimum follow-up was 18 months. RESULTS: Hearing was preserved in 69% of patients who underwent the MCF approach but in only 33% of patients for whom the RS approach was used. The RS approach was used for larger tumors (mean diameter 15 mm) and the MCF procedure for smaller tumors (mean diameter 9 mm). One hundred percent of patients had facial function H/B grade II or better, regardless of approach. CONCLUSION: Hearing function can be reliably preserved in a high percentage of selected patients undergoing resection of vestibular schwannoma.     

Our surgical experience with large vestibular schwannomas

Our aim is to remove large vestibular schwannomas (VS) radically with minimal morbidity. Usually, these tumours cannot not be treated by irradiation. In the years 1997-2003, 69 VS were operated in the Department of Otorhinolaryngology, Head and Neck Surgery of the First Medical Faculty in Prague, Czech Republic. Prevailing majority of these tumours were of the 4th grade (House classification), compressing the brainstem. Six patients in the group suffered from neurofibromatosis 2, in five cases the patients were indicated for neurosurgery due to rapid tumour growth after previous irradiation. All tumours were radically removed using a retromastoid osteoplastic and translab approach with an intraoperative nerve monitoring. Good function of the facial nerve was achieved in 90%. The nerve had to be resutured in 4 cases with consequent satisfactory results, cross anatomosis was not performed. Hearing function was preserved in 8% of patients only. In 6 patients with neurofibromatosis 2, the auditory brainstem implant (ABI) was used to preserve hearing. This study demonstrates that a radical removal of large vestibular schwannomas is possible using a minimally invasive surgical technique and peroperative nerve monitoring with a good impact on quality of life. Auditory brainstem implants bring a new chance of hearing after tumour removal in patients with NF2.     

Management strategies in neurofibromatosis type 2

The objective of this study was to review the experience of the Neurotology and Skull Base Surgery Unit of Addenbrooke's Hospital in Cambridge, England, in the management of patients with neurofibromatosis type 2 (NF2). This was a retrospective review of the institution's series conducted at a neurotological tertiary referral centre. Over a 17-year period (1984-2001), 35 patients with NF2 were managed. These patients presented with multiple cranio-spinal neoplasms, including 62 cerebellopontine angle tumours of which 59 were vestibular schwannomas (nine patients with unilateral tumours and 25 patients with bilateral tumours). Clinical presentation, diagnosis and patient management were reviewed. The outcome parameters measured were tumour progression, the incidence of complications (hearing deterioration and facial nerve palsy) and the need for secondary intervention. Five vestibular schwannomas were treated with stereotactic radiosurgery (gamma-knife), all of which showed evidence of progression in size and/or deterioration in hearing. Thirty-one VS were conservatively treated with annual surveillance. In nine cases, the tumours had a follow-up shorter than 6 months and were therefore excluded from the results. In 13 cases the VS did not progress in size, and the hearing remained stable, while in the remaining nine cases, tumour progression was evident. In fifteen cases, surgery was performed at the authors' institution. In 11 cases a translabyrinthine approach was adopted, and in the remaining four cases a retrosigmoid approach was preferred. In all these cases, tumour removal was total and facial nerve function was House-Brackmann grade I-III in 55%. Successful hearing preservation was elusive in those patients in whom a hearing preservation approach was attempted. NF2 remains an extremely challenging disorder for the neurotologist and the patient alike. Early diagnosis offers distinct advantages to the patients, their families and the community at large. Of the treatment modalities, surgery unequivocally offers the most superior tumour control. Hearing preservation remains a challenge in these patients, but is optimised by the early detection of tumours in the NF2 patient.