Frameless stereotactic radiosurgery for the treatment of primary intracranial tumours in dogs.

Stereotactic radiosurgery (SRS) is a procedure that delivers a single large radiation dose to a well-defined target. Here, we describe a frameless SRS technique suitable for intracranial targets in canines. Medical records of dogs diagnosed with a primary intracranial tumour by imaging or histopathology that underwent SRS were retrospectively reviewed. Frameless SRS was used successfully to treat tumours in 51 dogs with a variety of head sizes and shapes. Tumours diagnosed included 38 meningiomas, 4 pituitary tumours, 4 trigeminal nerve tumours, 3 gliomas, 1 histiocytic sarcoma and 1 choroid plexus tumour. Median survival time was 399 days for all tumours and for dogs with meningiomas; cause-specific survival was 493 days for both cohorts. Acute grade III central nervous system toxicity (altered mentation) occurred in two dogs. Frameless SRS resulted in survival times comparable to conventional radiation therapy, but with fewer acute adverse effects and only a single anaesthetic episode required for therapy.

Gamma Knife surgery for the management of glomus tumors: a multicenter study.

OBJECT: Glomus tumors are rare skull base neoplasms that frequently involve critical cerebrovascular structures and lower cranial nerves. Complete resection is often difficult and may increase cranial nerve deficits. Stereotactic radiosurgery has gained an increasing role in the management of glomus tumors. The authors of this study examine the outcomes after radiosurgery in a large, multicenter patient population. METHODS: Under the auspices of the North American Gamma Knife Consortium, 8 Gamma Knife surgery centers that treat glomus tumors combined their outcome data retrospectively. One hundred thirty-four patient procedures were included in the study (134 procedures in 132 patients, with each procedure being analyzed separately). Prior resection was performed in 51 patients, and prior fractionated external beam radiotherapy was performed in 6 patients. The patients' median age at the time of radiosurgery was 59 years. Forty percent had pulsatile tinnitus at the time of radiosurgery. The median dose to the tumor margin was 15 Gy. The median duration of follow-up was 50.5 months (range 5-220 months). RESULTS: Overall tumor control was achieved in 93% of patients at last follow-up; actuarial tumor control was 88% at 5 years postradiosurgery. Absence of trigeminal nerve dysfunction at the time of radiosurgery (p = 0.001) and higher number of isocenters (p = 0.005) were statistically associated with tumor progression-free tumor survival. Patients demonstrating new or progressive cranial nerve deficits were also likely to demonstrate tumor progression (p = 0.002). Pulsatile tinnitus improved in 49% of patients who reported it at presentation. New or progressive cranial nerve deficits were noted in 15% of patients; improvement in preexisting cranial nerve deficits was observed in 11% of patients. No patient died as a result of tumor progression. CONCLUSIONS: Gamma Knife surgery was a well-tolerated management strategy that provided a high rate of long-term glomus tumor control. Symptomatic tinnitus improved in almost one-half of the patients. Overall neurological status and cranial nerve function were preserved or improved in the vast majority of patients after radiosurgery.

Stereotactic radiosurgery for trigeminal schwannoma: tumor control and functional preservation Clinical article.

OBJECT: To evaluate outcome predictors after stereotactic radiosurgery (SRS) in patients with trigeminal schwannomas, the authors compared tumor control, functional preservation, and complications with tumor grade, tumor volume, patient age, and tumor imaging characteristics. METHODS: The records of 33 consecutive patients with trigeminal schwannoma treated via Gamma Knife surgery were retrospectively reviewed. The median patient age was 49.5 years (range 15.1-82.5 years). Eleven patients had undergone prior tumor resection. Two patients had neurofibromatosis Type 2. Lesions were classified as root type (6 tumors), ganglion type (17 tumors), and dumbbell type (10 tumors) based on their location. The median radiosurgery target volume was 4.2 cm3 (range 0.5-18.0 cm3), and the median dose to the tumor margin was 15.0 Gy (range 12-20 Gy). RESULTS: At an average of 6 years (range 7.2-147.9 months), the rate of progression-free survival (PFS) at 1, 5, and 10 years after SRS was 97.0, 82.0, and 82.0%, respectively. Factors associated with improved PFS included female sex, smaller tumor volume, and a root or ganglion tumor type. Neurological symptoms or signs improved in 11 (33.3%) of 33 patients and were unchanged in 19 (57.6%). Three patients (9.1%) had symptomatic disease progression. Patients who had not undergone a prior tumor resection were significantly more likely to show improvement in neurological symptoms or signs. CONCLUSIONS: Stereotactic radiosurgery is an effective and minimally invasive management option in patients with residual or newly diagnosed trigeminal schwannomas. Predictors of a better treatment response included female sex, smaller tumor volume, root or ganglion tumor type, and the application of SRS as the primary treatment.

Trigeminal neuroma: analysis of surgical experience with 73 cases.

OBJECTIVE: We reviewed the clinical and radiological features of 73 cases of trigeminal neuromas treated with radical surgery. METHODS: The records for 73 patients with trigeminal neuromas who were surgically treated in the neurosurgery department of King Edward VII Memorial Hospital and Seth Gordhandas Sunderdas Medical College (Mumbai, India), between 1989 and 2001, were retrospectively analyzed. The appropriateness of the selected surgical route was studied. The postoperative and follow-up data for the patients were analyzed, to determine the outcomes of radical surgery. RESULTS: In addition to the other presenting features of trigeminal neuromas, nine patients presented with the rarely reported symptom of pathological laughter. Three approaches were observed to be appropriate for treatment of these tumors, i.e., the infratemporal fossa interdural approach, the lateral basal subtemporal approach, and the retrosigmoid approach. In 51 cases (70%), total tumor excision was achieved. Two patients died during the postoperative period. With an average follow-up period of 38 months, there has been a recurrence in 1 case and 71 patients are leading independent and active lives. CONCLUSION: Radical surgery is associated with excellent clinical outcomes and long-term tumor control. A majority of tumors, even those that are large and multicompartmental, can be removed in a single surgical stage and exposure.