The effect of fractionated gamma knife radiosurgery on visual acuity in patients with optic nerve tumor.

BACKGROUND: Stereotactic radiosurgery (SRS) method has been considered the first-line treatment option to treat patients involved with pre-optic nerve tumors. However, studies have shown that using fractionated SRS, normal tissue sparing and tumor dose can be strongly increased simultaneously. Our main goal was to illustrate the effects of fractionated SRS approach in optic nerve tumor treatment and its adjacent sensitive structures. MATERIALS AND METHODS: 19 patients involved in optic nerve tumor with clinical symptoms of vision loss were treated with Gamma Knife radiosurgery in three sessions with 12 hours intervals between them. The prescribed dose was about 6.0 ± 1.2 Gy. Patient-related parameters including pre-treatment and after-treatment tumor size, visual acuity and visual field were evaluated using the Snell chart and MRI imaging. Patients were followed for about 14 months. RESULT: The overall result showed vision improvement for patients with low and moderate visual loss. However, there was no significant improvement in patients with severe visual loss. Relative improvement was observed in blind patients, although poorly. There was no evidence of growth, recurrence, or new tumor after treatment in patients. CONCLUSION: Fractionated gamma knife radiosurgery offers a safe and effective alternative for benign lesions adjacent to the optic nerve.

Radiosurgery in treatment of cerebral arteriovenous malformation: Mid-term results of 388 cases from a single center.

BACKGROUND AND OBJECTIVES: The purpose of this study is to evaluate the outcome and risks of radiosurgery for patients with arteriovenous malformations (AVM) of the brain all treated in a single center in the 3rd world with all its limitations. MATERIALS AND METHODS: We performed a retrospective analysis of 388 patients with AVM treated with radiosurgery during an 8-year period. Factors associated with increased chance of AVM obliteration or hemorrhages during the follow-up period were analyzed. RESULTS: Among 388 cases included in our series, 74 were Spetzler-Martin (SM) grade IV or V. Forty-four patients (11.3%) experienced post-radiosurgery hemorrhage in their follow-up period. The number of feeders (one/multiple) and deep location of the AVM did not alter the chance of bleeding (P < 0.05). Higher SM grading of the AVM was associated with increased chance of hemorrhage and decreased obliteration rate (P > 0.05) in the mid-term follow up. CONCLUSIONS: Our case series showed that radiosurgery can be considered a viable alternative in the treatment of even large AVMs which might not be considered good candidates for surgery or endovascular treatment. Further data including large size lesions are warranted to further support our findings.

Gamma knife radiosurgery in patients with trigeminal neuralgia: quality of life, outcomes, and complications.

OBJECTIVE: to assess the outcomes, complications, and alteration in quality of life (QOL) in patients with trigeminal neuralgia who were treated with gamma knife radiosurgery (GKRS) in a prospective observational study. METHODS AND MATERIALS: between June 2006 and May 2007, 30 patients of medically refractory trigeminal neuralgia were included in our study and treated with GKRS at Iran Gamma Knife Centre (IGKC), Tehran, Iran. A median maximum prescription dose of 90Gy (range: 85-95) was delivered to the trigeminal nerve root entry zone. All involved patients completed QOL questionnaire SF-36 before GKRS and 9-12 months after it. All data from questionnaires and the basic characteristics of the radiosurgery and patients were analyzed using descriptive statistics, paired T-test, Fisher's exact test, bivariate correlation, and independent sample T-test. RESULTS: In all SF-36 domains significant changes before and after GKRS were noticed except physical function (PF) and role limitation due to physical problem (RP). Bodily pain after GKRS was 100 (excellent result) in 12 (40%) of study participants, 90-99 (good result) in 3 (10%), 50-89 (fair result) in 10 (33%) and less than 50 (poor result) in five (17%). Four cases (13%) faced to facial numbness. No other complications were noticed. CONCLUSIONS: GKRS positively changes the several aspect of QOL especially those related to pain relief and mental health component of QOL. The rate of diminishing pain in our study is comparable with other series. The GKRS complication is limited in both variety and number.

Near-infrared laser spectroscopy as a screening tool for detecting hematoma in patients with head trauma.

INTRODUCTION: Among imaging techniques, computed tomography (CT) is a reliable method for detecting intracranial hematomas in patients with head trauma, but it is not generally available in special circumstances like prehospital situations and harsh conditions such as those following an earthquake. OBJECTIVE: The objective of this study is to determine if near-infrared spectroscopy (NIRS) is useful for performing CT scans on patients with closed head trauma that present to medical centers that do not have the ability to perform a CT scan or in prehospital or harsh situations. Near-infrared spectroscopy and CT scan were compared according to sensitivity and specificity. METHODS: This was an observational, prospective study. One hundred forty-eight patients admitted to Rasool Akram General Hospital in Tehran, Iran with head injuries during a one-month period were studied using NIRS and CT. The observational, prospective study was conducted and sensitivity, specificity, positive and negative predictive values of NIRS were calculated. Chi-square and Kappa analysis was performed, and a p-value <0.05 was considered significant. RESULTS: According to the CT scan findings, 54 (36.5%) of the patients developed intracranial hematoma. The NIRS examination showed that 69 patients (46.6%) might have intracranial hematoma. The number of true negatives was 73 and the number of false negatives was six patients. The sensitivity and specificity of NIRS examination was 88.9% and 77.7%, respectively. CONCLUSIONS: This study speculates that NIRS may be a useful screening tool to detect intracranial hematoma. This capability could be useful in special situations like in a deprived area, medical centers without CT scan capabilities, prehospital situations, and in harsh conditions like those after an earthquake or other disasters that causes increased numbers of victims with closed head trauma.