Faculty Bibliography

BACKGROUND: A therapeutic radiosurgery procedure usually follows a separate diagnostic stereotactic procedure after days or weeks. OBJECTIVES: To define the clinical reliability, safety, and cost implications of same-day diagnostic stereotactic biopsy and therapeutic radiosurgery. METHODS: During an 8-year interval, 26 patients underwent stereotactic brain biopsy followed by immediate therapeutic stereotactic radiosurgery in a single-day combined procedure. The intraoperative diagnosis was determined using standard histopathological techniques. Diagnostic accuracy, hospital costs, and contribution margins associated with this treatment strategy were compared to those of 26 case-matched patients (controls) who underwent a stereotactic diagnostic procedure followed by a separate-day outpatient SRS procedure within 6 weeks during the same time interval. RESULTS: The intraoperative diagnosis correlated with the final histopathological diagnosis in 96% of the patients. Biopsy-related morbidity did not occur in this series. The mean total costs of same-day patients was significantly lower than the costs of patients who had two-stage procedures (USD 9,077 +/- 2,366 vs. 11,284 +/- 3,025; p = 0.008). The net contribution to the hospital margin of USD 13,736 was not significantly different between the two management strategies. CONCLUSIONS: The advantages of the same-day approach included a single stereotactic head frame application, reduced total admission time, consecutive histopathological diagnosis and therapy in a single hospital admission, and reduced total hospital costs. For patients who are highly suspected to have a brain tumor for which SRS is likely to be an effective therapeutic strategy, same-day diagnostic stereotactic biopsy followed by therapeutic SRS proved to be a safe, reliable, and cost-effective management strategy.

BACKGROUND: The management of trigeminal neuralgia in patients with associated skull base meningiomas is complex. OBJECTIVE: We evaluated the pain management needs and outcomes in patients with petroclival meningiomas associated with medically refractory trigeminal neuralgia. METHODS: During a 21-year period, 168 patients underwent stereotactic radiosurgery (SRS) for meningiomas involving the petroclival region. We identified 12 patients (10 females; median age 54 years) who had trigeminal neuralgia in association with an ipsilateral petroclival meningioma. The median tumor volume was 3.8 cm(3) (1.0-15.9 cm(3)). The median prescription dose for tumor margins was 13 Gy (11-16 Gy). RESULTS: Initial pain control [Barrow Neurological Institute (BNI) grades I-IIIb] was obtained in 10 of 12 patients (83%). However, 3 patients with initial adequate relief later developed pain. Follow-up imaging revealed control of tumor growth in all patients at a median follow-up of 68 months. No patient developed any new sensory dysfunction. The tumor shrinkage was not associated with pain relief. At the final follow-up, 5 patients had pain of BNI grade I (2 after surgery), 4 had grade IIIb and 3 had grade IV. CONCLUSIONS: SRS provided effective tumor control, but trigeminal neuralgia persisted to varying degrees in most patients. Multimodality pain management strategies were required in most patients with skull base meningiomas associated with trigeminal neuralgia.

The technique of central nervous system cell implantation can affect the outcome of preclinical or clinical studies. Our goal was to evaluate the impact of various injection parameters that may be of consequence during the delivery of solute-suspended cells. These parameters included (1) the type and concentration of cells used for implantation, (2) the rate at which cells are injected (flow rate), (3) the acceleration of the delivery device, (4) the period of time between cell loading and injection into the CNS (delay), and (5) the length and gauge of the needle used to deliver the cells. Neural progenitor cells (NPCs) and bone marrow stromal cells (BMSC) were injected an automated device. These parameters were assessed in relation to their effect on the volume of cells injected and cell viability. Longer and thinner cannulae, and higher cell concentrations were detrimental for cell delivery. Devices and techniques that optimize these parameters should be of benefit.

OBJECTIVE: It is possible to judge the impact of scientific research by the number of citations a publication has received. We identified the most cited works in the field of stereotactic radiosurgery to study the evolution of this field from the perspective of publication. METHODS: A Web of Science search was performed for articles that included the word 'radiosurgery' in the title. We studied the reports with >100 citations. RESULTS: A total of 5,532 published works were available for study between 1951 and 2010. Eighty-five articles had >/= 100 citations, and these were published in 19 separate journals. The majority were published in the International Journal of Radiation Oncology, Biology and Physics, the Journal of Neurosurgery and Neurosurgery. The most common topics included brain metastasis management (n = 20), arteriovenous malformations (n = 17), vestibular schwannomas (n = 9), technologies (n = 9), meningiomas (n = 8) and dose response/radiobiology (n = 6). Fifty-seven percent of the articles were published in the last 10 years. CONCLUSIONS: The first radiosurgery report by Leksell (1951) initiated the field. The 1980s were a period of new technology development followed in the 1990s by introductory articles on specific indications that consisted mainly of retrospective case series. More sophisticated higher level evidence reports were published in the last decade. The most significant works in radiosurgery include initial technology descriptions, multicenter studies with large numbers of patients, randomized clinical trials and reports that provide dose prescription guidelines.