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Item does not contain fulltext OBJECTIVES/HYPOTHESIS: Gamma knife radiosurgery (GKRS) has become an important treatment modality for vestibular schwannomas. The primary aim of this study was to investigate whether tumor growth at the moment of GKRS has any correlation with the outcome. The secondary aim was to identify clinical predictors of radioresistance in vestibular schwannoma patients treated with GKRS. STUDY DESIGN: One hundred vestibular schwannoma patients, treated with GKRS, were divided into two groups: 1) proven tumor growth preceding GKRS; and 2) previous history of growth unknown. GKRS outcome was defined in two ways. According to the first definition, GKRS was said to have failed when additional treatment had taken place. According to the second one, a volume decrease >20% after 2 years marked successful treatment. METHODS: Correlations between outcome and growth status were determined with SPSS software. Furthermore, the study assessed how different variables (patient data, history, tumor characteristics, imaging, and audiovestibular examinations) correlated with the outcome of GKRS. RESULTS: No significant difference regarding success and failure of GKRS was found between the two patient groups. The mean reduction in tumor volume after GKRS was less pronounced in patients in whom tumor growth was demonstrated before treatment, but this finding was not significant. No significant predictors (P < .05) could be identified in this data set. CONCLUSIONS: This study found no indication that growth at the moment of GKRS influences therapeutic outcome, nor did it identify any predictors of the outcome after GKRS in vestibular schwannoma patients.

Contains fulltext : 68925.pdf ( ) (Open Access) 4 p.

Item does not contain fulltext A 13-year-old patient was referred to the ENT department because of a ring-shaped radiopaque foreign body in her right nasal cavity demonstrated on an orthopantomogram. Her medical history revealed long-standing right-sided rhinorrhea thought to be caused by an inhalation allergy. In case of unilateral rhinorrhea in a child a nasal foreign body has to be excluded.

Contains fulltext : 91391.pdf (Publisher’s version ) (Open Access) Radboud Universiteit Nijmegen, 30 november 2011 Promotor : Graamans, K. Co-promotor : Mulder, J.J.S. 168 p.

Contains fulltext : 80665timmer.pdf (Publisher’s version ) (Closed access) OBJECTIVES/HYPOTHESIS: This study was designed to evaluate hearing preservation after gamma knife radiosurgery (GKRS) and to determine the relation between hearing preservation and cochlear radiation dose in patients with a sporadic vestibular schwannoma (VS). METHODS: Prospective study involving patients suffering from VS who received GKRS from June 2003 until November 2007. Pure tone and speech audiometry were conducted before and after GKRS. The thresholds at pure tone audiometry were taken as a measure of hearing. Pure tone average (PTA) was defined as the mean threshold at 0.5 kHz, 1.0 kHz, 2.0 kHz, and 4.0 kHz. Hearing was classified according to the 2003 consensus meeting in Tokyo. Stereotactic surgery was performed using a Leksell 4C Gamma Knife (Elekta, Stockholm, Sweden). RESULTS: A total of 69 patients were included in the study. Mean tumor size was 17 mm. Mean marginal dose at the tumor was 11.0 Gy (range, 9.3 Gy-12.3 Gy), mean maximal dose was 19.7 Gy (range, 16 Gy-25.5 Gy). Mean maximal dose at the cochlea was 10.27 Gy (range, 3.1 Gy-16.1 Gy), and mean minimal dose at the cochlea was 2.6 Gy (range, 0.9 Gy-7.4 Gy). Mean PTA before GKRS was 43 dB (standard deviation [SD] 20 dB), mean PTA after GKRS was 63 dB (SD 30 dB). Mean interval between pre-GKRS audiometry and GKRS was 8.0 months. Between GKRS and post-GKRS audiometry, mean interval was 14.2 months. Hearing was considered to be preserved (max +1 class, Tokyo classification) in 52 (75%) of 69 patients. However, only 32 patients had class A, B, or C (serviceable hearing) before GKRS. Within this group, only 13 patients (41%) had a hearing class A, B, or C after GKRS. A significant relation was found between the maximal cochlear dose and the difference in PTA before and after GKRS. CONCLUSIONS: Hearing preservation is correlated to the maximal radiation dose at the cochlea. The purpose of developing GKRS techniques was to avoid collateral damage in healthy tissues. This study emphasizes the need for exact radiation planning to reduce the cochlear radiation dose if the hearing is to be preserved. Laryngoscope, 2009.

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Item does not contain fulltext 40 p.