Stereotactic radiotherapy in three weekly fractions for the management of vestibular schwannomas

Purpose

This study evaluates the rates of tumor control, hearing preservation and cranial nerve toxicity with the use of CyberKnife stereotactic radiotherapy consisting of 2100?cGy to the 80% isodose line delivered in three weekly fractions to treat vestibular schwannomas.

Predictors of future growth of sporadic vestibular schwannomas obtained by history and radiologic assessment of the tumor

Management of a sporadic vestibular schwannoma (VS) is still a subject of controversy, mainly due to distinct and unpredictable growth patterns. To embark on an appropriate therapy it is necessary to dispose of a reliable prediction about tumor progression. This study aims to design a risk profile with predictors for VS growth. A total of 234 VS patients who were managed conservatively were included. Data concerning (duration of) symptoms and localization of VS were analyzed with Cox proportional hazards regression models. Predictors for growth are unsteadiness/vertigo, no sudden onset of hearing loss and short duration of hearing loss. High-risk patients have (1) VS with an extrameatal localization, short duration of hearing loss and at least one of the two other predictors (unsteadiness/vertigo or no sudden sensorineural hearing loss) or (2) VS with an intrameatal localization and all three other predictors. Low-risk patients have (1) VS with an extrameatal component and no other predictor or (2) VS with an intrameatal localization and at most one other predictor. High-risk patients have a risk of growth of 36.9% in the first year and 64.6% in the second year. For patients with a low risk this is 2.5 and 12.7%, respectively. Simple data gathered at the moment of diagnosis may provide useful information since they may lead to a risk profile for growth.     

以反复眩晕为主诉的单侧多发性前庭神经鞘瘤1例报道

<正>前庭神经鞘瘤也称听神经瘤^[1],为内听道、桥小脑角区最常见的良性肿瘤。它会引起听力下降、耳鸣或眩晕;随着肿瘤的生长并向小脑脑桥角扩展,压迫脑桥、延脑,并出现脑积水、颅内高压,进而危及患者生命^[2]。2021年8月我院收治了1例以眩晕为主诉的多发性前庭神经鞘瘤患者,后转诊至301医院,成功为患者施行了右侧迷路入路肿瘤切除手术,术中证实为右耳迷路多发性前庭神经鞘瘤。现对该病例报道如下:     

Electronystagmographic changes in patients with unilateral vestibular schwannomas in relation to tumor progression and central compensation

Vestibular function was studied in a group of 121 patients with unilateral vestibular schwannomas who were referred to University Hospital Utrecht between 1986 and 1996. Testing included the caloric test, torsion test, saccade test, smooth pursuit test and the registration of spontaneous nystagmus. Each patient’s symptoms were taken from a chart review. The size of the tumor was expressed as the maximum extrameatal diameter in the axial plane parallel to the petrous ridge as seen in magnetic resonance imaging or computed tomography. Large tumors were significantly more often accompanied by a more severe paresis on caloric testing, a smaller gain on torsion testing, spontaneous nystagmus, an abnormal saccade test and an abnormal smooth pursuit test. The presence of spontaneous nystagmus was significantly more frequently combined with an abnormal smooth pursuit and saccade test. There was a significant correlation between the slow component’s velocity of the spontaneous nystagmus and the size and progression of tumor. However, a specific relation between tumor size and central vestibular compensation could not be demonstrated. Received: 5 January 1998 / Accepted: 14 August 1998     

Factors affecting hearing deterioration in vestibular schwannoma patients treated with gamma knife radiosurgery: the Asan Medical Center experience

Objectives: To investigate the changes in hearing and to determine factors predicting hearing deterioration in patients with vestibular schwannoma (VS) who undergo gamma knife radiosurgery (GKRS).

Design: A retrospective review of medical records in patients diagnosed with VS and initially treated with GKRS at a tertiary care medical center between 1995 and 2015 was performed. Tumor factors (location, volume), parameters related to irradiation to the tumor and cochlea, and distance between the tumor and cochlea were reviewed.

Results: Fifty-six patients were included in the final analysis with a mean observation period following GKRS as 24.4?±?27.8 months. Prior to GKRS, the average pure tone threshold at 500, 1k, 2k, and 4k?Hz (PTA₄) was 51.0?±?29.7?dB HL. After GKRS, the mean PTA₄ was 71.6?±?33.3?dB HL. Significant independent odds ratios for hearing deterioration were 8.5 for extracanalicular tumors, 18.8 for more than 10 shots in GKRS, and 12.2 for a distance between the tumor center and cochlea modiolus less than 20?mm.

Conclusions: A significant hearing deterioration was shown in 2 years after GKRS. Tumor location, number of radiation shots, and distance between the tumor and cochlea affected hearing level after GKRS.     

眼动功能定量分析在前庭疾病中鉴别诊断的意义

目的探讨眼动功能定量分析检查在鉴别不同类型前庭疾病中的作用.方法本文收集181例眼动功能定量分析资料,其中正常组40例,突发性聋组46例,药物中毒性眩晕组26例,梅尼埃病组48例,听神经瘤组21例,分别进行扫视、跟随及视动试验定量分析检查.结果周围性前庭病变各项检查与正常组比较无统计学差异;听神经瘤组扫视试验潜伏期延长,达246ms+66ms,较正常组190ms+25ms明显延长,跟随试验各项指标均示异常,视动性检查最大慢相速度及平均慢相速度减慢,分别为18.4°/s±6.4°/s和16.0°/s±6.0°/s,较正常组22.6°/s±8.8°/s和20.3°/s±8.7°/s减慢.结论提示眼动功能定量分析检查对鉴别前庭周围性和中枢性病变有一定参考价值.     

Small vestibular schwannomas with no hearing: comparison of functional outcomes in stereotactic radiosurgery and microsurgery

Objectives: To date, numerous studies have compared functional outcomes between stereotactic radiosurgery (SRS) and microsurgery (MS) in the treatment of vestibular schwannomas (VS). However, most of them involve tumors of difference sizes, radiation dosages, and surgical approaches. Few have systematically compared issues of dysequilibrium. By studying only patients with small tumors and no hearing, we sought to minimize confounding variables. Study Design: A retrospective chart review and telephone questionnaire. Methods: From 1998–2006, 31 patients with small (<1.5 cm) VS and nonserviceable hearing (American Academy of Otolaryngology–Head and Neck Surgery [AAO‐HNS] Class C or D) were treated at our institution. Twenty‐two were available for follow‐up and telephone questionnaire, including the University of California Los Angeles Dizziness Questionnaire (UCLA‐DQ). Twelve underwent SRS and 10 underwent MS. All MS patients underwent the translabyrinthine approach to their tumors. Outcomes measurements included tumor control, facial nerve function, tinnitus, trigeminal function, and imbalance. Results: Patients undergoing SRS had comparable rates of tumor control, facial nerve function, tinnitus, and trigeminal function to MS patients. However, SRS did result in statistically significantly worse long‐term imbalance when compared with MS patients. Detailed comparisons of the two modalities are made. Conclusions: In our study population, patients with small tumors and no serviceable hearing, these data suggest that MS results in comparable minimal morbidity with SRS, though posttreatment dysequilibrium is significantly decreased. While the authors recommend translabyrinthine resection of small VS with no hearing in patients able to tolerate surgery, the need for further prospective investigation is clear.     

Cyclin D(1) and D(3) expression in vestibular schwannomas

OBJECTIVES: The G1 regulators of the cell cycle, cyclin D(1) and D(3), have been implicated in the regulation of Schwann cell proliferation and differentiation. The purpose of this study is to evaluate cyclin D(1) and D(3) protein expression and the corresponding clinical characteristics of vestibular schwannomas. STUDY DESIGN AND METHODS: Tissue sections of 15 sporadic vestibular schwannomas were prepared. Immunohistochemical analysis of the vestibular schwannomas was performed with anticyclin D(1) and anticyclin D(3) antibodies. The immunoreactivity was evaluated in comparison with adjacent vestibular nerves. Tissue sections of breast carcinoma and prostate carcinoma were used as positive controls for cyclin D(1) and D(3) staining, respectively. Patient demographics, tumor characteristics, and cyclin D expression were reviewed, and statistical analysis was performed. RESULTS: While the breast carcinoma control expressed abundant cyclin D(1) protein, none of the 15 vestibular schwannomas showed detectable cyclin D(1) staining. In contrast, seven of 15 vestibular schwannomas stained positive for the cyclin D(3) protein. Cyclin D(3) staining was taken up in the nucleus of schwannoma tumor cells in greater proportion than Schwann cells of adjacent vestibular nerve. Although sample size was small, no significant difference in the average age of presentation, tumor size, and male to female ratios for the cyclin D(3)(+) or cyclin D(3)(-) groups was found. CONCLUSION: The Cyclin D(1) protein does not appear to play a prominent role in promoting cell cycle progression in vestibular schwannomas. In contrast, cyclin D(3) expression was seen in nearly half of the tumors examined, suggesting that it may have a growth-promoting role in some schwannomas. Further studies are needed to define its cellular mechanism.     

Jugular foramen schwannomas: diagnosis, management, and outcomes

OBJECTIVES/HYPOTHESIS: To describe the presentation, radiographic findings, and surgical management of seven patients who have been diagnosed and treated with jugular foramen schwannomas at the University of Utah. STUDY DESIGN: Retrospective chart review. METHODS: The charts of seven patients diagnosed with jugular foramen schwannomas were reviewed for presentation symptoms, radiographic findings, and physical examination findings. For the six who underwent surgical excision, the surgical procedure used, cranial nerve function results, audiometric results, perioperative complications, and other follow-up data are presented. RESULTS: Seven patients were identified from ages 24 to 69 years. Six of the seven underwent surgical excision. Primary presentation symptoms included dizziness, hearing loss, dysphagia, diplopia, tongue paresis, and hoarseness. The choice of surgical approach was based on the size and location of the tumor. All patients had complete excision of their tumors. The nerve of origin included the glossopharyngeal, vagus, and spinal accessory nerves. Preoperative cranial nerve dysfunction continued postoperatively for lower cranial nerves but resolved in patients who were noted to have preoperative dysfunction of cranial nerve V and VI. The rate of new lower cranial nerve injury was 15% and was only seen in the cranial nerves that were determined to be the nerve of origin. In two cases, a temporary feeding tube was required. No recurrences have been noted to date. CONCLUSIONS: Jugular foramen schwannomas can be successfully diagnosed preoperatively with computed tomography and magnetic resonance imaging. These tumors can be successfully managed with surgery and low morbidity.