Hypofractionated stereotactic radiotherapy of acoustic neuroma: volume changes and hearing results after 89-month median follow-up.

PURPOSE: The goal of this work was to evaluate toxicity and local control following hypofractionated stereotactic radiation treatment with special focus on changes in tumor volume and hearing capacity. PATIENTS AND METHODS: In all, 29 patients with unilateral acoustic neuroma were treated between 2001 and 2007 within a prospective radiation protocol (7 × 4 Gy ICRU dose). Median tumor volume was 0.9 ml. Follow-up started at 6 months and was repeated annually with MRI volumetry and audiometry. Hearing preservation was defined as preservation of Class A/B hearing according to the guidelines of the American Academy of Otolaryngology (1995). RESULTS: No patient had any intervention after a median imaging follow-up of 89.5 months, one patient showed radiological progression. Transient increase of tumor volume developed in 17/29 patients, whereas 22/29 patients (75.9%) presented with a volume reduction at last follow-up. A total of 21 patients were eligible for hearing evaluation. Mean pure tone average (PTA) deteriorated from 39.3 to 65.9 dB and mean speech discrimination score (SDS) dropped from 74.3 to 38.1%. The 5-year actuarial Class A/B hearing preservation rate was 50.0 ± 14.4%. CONCLUSION: Radiation increases only minimally, if at all, the hearing deterioration which emerges by observation alone. Presbyacusis is not responsible for this deterioration. Transient tumor enlargement is common. Today radiation of small- and medium-sized acoustic neuroma can be performed with different highly conformal techniques as fractionated treatment or single low-dose radiosurgery with equal results regarding tumor control, hearing preservation, and side effects. Hypofractionation is more comfortable for the patient than conventional regimens and represents a serious alternative to frameless radiosurgery.

Efficacy of cerebrospinal fluid fistula repair: sensitive quality control using the beta-trace protein test.

BACKGROUND: After cerebrospinal fluid (CSF) fistula repair, the goal of watertight sealing may not always be achieved, causing postoperative CSF leakage. The aim of this study was to assess the novel application of the beta-trace protein (betaTP) test for postoperative screening and confirmation of dura repair success. METHODS: Prospectively, we investigated 32 consecutive patients who underwent dura repair. Postoperative nasal secretion and serum were analyzed for CSF marker betaTP, to detect or rule out postoperative CSF leakage. RESULTS: In 29 patients no CSF was detected, indicating 91% dura repair success after the first step. Three patients required additional surgery, verifying CSF leak. Additional betaTP testing was negative, revealing successful dura repair. CONCLUSION: Dura repairs should be controlled for the presence or absence of postoperative CSF leakage. In our hands, the sensitive, fast, and inexpensive betaTP test has shown its value as an effective postoperative screening tool for dura repair success confirmation. Therefore, we consider it as novel "standard of care" and reserve invasive, more expensive or time-consuming methods as second choice.

Comprehensive algorithm for skull base dural lesion and cerebrospinal fluid fistula diagnosis.

OBJECTIVES/HYPOTHESIS: Skull base dural lesions and cerebrospinal fluid (CSF) fistulas are potentially vital conditions whose diagnosis can be challenging. The authors' aim was to compose a comprehensive algorithm that combines the most modern diagnostic tools in easily applicable patterns to indicate a possible dural lesion or CSF fistula. STUDY DESIGN: Prospective clinical study. METHODS: The authors collected the data of all patients with suspicion of CSF fistula or dural lesion, or both, between January 1999 and December 2002. Beta-trace protein, beta2-transferrin, and endoscopic and laboratory sodium fluorescein tests; high-resolution computed tomography; and magnetic resonance cisternography were used according to the symptoms and etiological factors. The results of the diagnostic tools that were used and intraoperative findings (in case of an operative treatment) were reviewed. RESULTS: From 1999 to 2002, 236 patients were evaluated because of suspicion of dural lesion or CSF fistula, mostly after head trauma. Pattern I of the algorithm was applied for head trauma in dural lesion or CSF leak assessment, pattern II for postoperative CSF leaks, pattern III for evaluation of spontaneous CSF rhinorrhea, and pattern IV for the assessment of recurrent pneumococcal meningitis related to dural lesions without CSF fistula. By applying the patterns of this algorithm, a dural lesion or CSF leak that was also confirmed intraoperatively was detected in 48 patients. CONCLUSION: The four patterns of the new diagnostic algorithm described in the present study enable physicians to reliably clarify suspicions of dural lesions and CSF fistulas and aim to help them choose the best possible management. Each pattern uses the optimal combination of CSF tests and radiological imaging to reach a synergistic effect for precisely detecting dural lesions or CSF fistulas. Accordingly, this improves surgical decision-making when necessary.

Beta-trace protein test: new guidelines for the reliable diagnosis of cerebrospinal fluid fistula.

OBJECTIVE: Cerebrospinal fluid (CSF) fistulas need to be reliably diagnosed for the optimal management. Recently, in preference to beta2-transferrin, another CSF protein, beta-trace protein (betaTP), is similarly used with a new method for CSF diagnosis. This study evaluates the sensitive interpretation and limits of this new betaTP test for use in routine CSF fistula diagnosis. METHODS: Nephelometric detection of betaTP has been made in nasal secretion, serum, and CSF samples from healthy individuals as well as patients with reduced glomerular filtration rate and with bacterial meningitis. Additionally, 53 patients with suspected CSF rhinorrhea are also analyzed. RESULTS: The betaTP test can also be used to reliably diagnose CSF rhinorrhea even slightly better than the beta2-transferrin test. It should not be used for patients with renal insufficiency and bacterial meningitis as they substantially increase serum and decrease CSF betaTP values, respectively. CONCLUSION: Quantitative measurement of betaTP is a noninvasive, highly sensitive, quick, and inexpensive method that can be used for the detection of CSF rhinorrhea in nasal secretions. However, in cases where there is doubt about the interpretation, the results should be proved with beta2-transferrin test or sodium-fluorescein test.