Efficacy and cost-effectiveness analysis of external beam and stereotactic body radiation therapy in the treatment of spine metastases: a matched-pair analysis.

OBJECT: The objective of this study was to compare the palliative efficacy and cost effectiveness of external beam radiation therapy (EBRT) to stereotactic body radiation therapy (SBRT) as primary treatment for bone metastatic disease of the spinal column. METHODS: Forty-four patients were matched based on age, primary tumor site, year of treatment, and location of metastasis. Outcomes of interest were pain relief, cost-effectiveness, toxicities, and need for further intervention. Pain relief was rated as excellent, good, fair, or poor, using a radiosurgical pain scale to combine visual analog scale and verbal descriptor ordinal scale scores. Medicare fee schedules were used to compute the charges for both the technical and professional components of care. Patients in the EBRT group were treated using a linear accelerator while patients in the SBRT group were treated with the CyberKnife robotic radiosurgery system. Patients received regular follow-up evaluations by a radiation oncologist and neurosurgeon. RESULTS: Forty-four patients (22 pairs) were analyzed. At a follow-up of 1 month, there was no statistically significant difference in pain between the 2 groups (p = 0.11). Patients who underwent SBRT had the highest total gross charge; depending on technique, EBRT treatments ranged from 29% to 71% of the SBRT charge. Patients treated using EBRT had more acute toxicities, and more of these patients underwent further intervention at the treated spinal level. There were no late complications attributed to either treatment modality. CONCLUSIONS: External beam radiation therapy remains an efficacious and cost-effective method of palliation of spine metastases. In this study, patients treated with EBRT had more acute toxicities and were more likely to require additional interventions at the treated sites. Stereotactic body radiation therapy, although more costly, resulted in comparable rates of pain relief and late treatment-related toxicity, and continues to show promise as an emerging modality for selected patients with spine metastases.

Effect of fibrin glue on the prevention of persistent cerebral spinal fluid leakage after incidental durotomy during lumbar spinal surgery.

Approximately one million spinal surgeries are performed in the United States each year. The risk of an incidental durotomy (ID) and resultant persistent cerebrospinal fluid (CSF) leakage is a significant concern for surgeons, as this complication has been associated with increased length of hospitalization, worse neurological outcome, and the development of CSF fistulae. Augmentation of standard dural suture repair with the application of fibrin glue has been suggested to reduce the frequency of these complications. This study examined unintended durotomies during lumbar spine surgery in a large surgical patient cohort and the impact of fibrin glue usage as part of the ID repair on the incidence of persistent CSF leakage. A retrospective analysis of 4,835 surgical procedures of the lumbar spine from a single institution over a 10-year period was performed to determine the rate of ID. The 90-day clinical course of these patients was evaluated. Clinical examination, B-2 transferrin assay, and radiographic imaging were utilized to determine the number of persistent CSF leaks after repair with or without fibrin glue. Five hundred forty-seven patients (11.3%) experienced a durotomy during surgery. Of this cohort, fibrin glue was used in the dural repair in 278 patients (50.8%). Logistic models evaluating age, sex, redo surgery, and the use of fibrin glue revealed that prior lumbar spinal surgery was the only univariate predictor of persistent CSF leak, conferring a 2.8-fold increase in risk. A persistent CSF leak, defined as continued drainage of CSF from the operative incision within 90 days of the surgery that required an intervention greater than simple bed rest or over-sewing of the wound, was noted in a total of 64 patients (11.7%). This persistent CSF leak rate was significantly higher (P < 0.001) in patients with prior lumbar surgery (21%) versus those undergoing their first spine surgery (9%). There was no statistical difference in persistent CSF leak between those cases in which fibrin glue was used at the time of surgery and those in which fibrin glue was not used. There were no complications associated with the use of fibrin glue. A history of prior surgery significantly increases the incidence of durotomy during elective lumbar spine surgery. In patients who experienced a durotomy during lumbar spine surgery, the use of fibrin glue for dural repair did not significantly decrease the incidence of a persistent CSF leak.

Radiosurgical pathology of brain tumors: metastases, schwannomas, meningiomas, astrocytomas, hemangioblastomas.

Systematic human pathological background to brain tumor radiosurgery explaining biological and pathophysiological effects of focused irradiation barely exists. The goal of this study was to explore histopathological changes evoked by single high-dose irradiation in a set of different brain tumors following Gamma Knife radiosurgery (GKRS). Light microscopy revealed that GKRS evokes degenerative and proliferative pathological changes in the parenchyma, stroma and vessels of the irradiated tumors. Three main histological types of gamma radiolesions, that is acute, subacute and chronic variants of tissue reactions were recognized in different neoplasms irrespective of their ontogenetic nature. Acute type gamma radiolesions were characterized mainly with necrotic changes and appeared either early or in a delayed time interval. Subacute type gamma radiolesions expressed resorptive activity also with early or delayed chronology. Chronic type lesions showed a reparative tendency but presented only at the delayed stage. These changes seem to follow each other consecutively. There was no significant relation between morphological characteristics of the generated tissue reaction and the time interval elapsed after GKRS. This relative time and environment autonomy of the developed pathological lesions with similar histological picture in different neoplasms suggests either a vascular mechanism or/and a genetically directed origin presumably induced by the ionizing energy of high-dose irradiation.

Cerebral metastases pathology after radiosurgery: a multicenter study.

BACKGROUND: To the authors' knowledge, comprehensive human pathologic investigations that explore fundamental radiosurgical effects on metastatic brain tumors are sparse in the literature. The objective of this study was to analyze histopathologic findings in a set of clinically recurrent cerebral metastases after patients underwent stereotactic radiosurgery (SRS). METHODS: In a series of 7500 patients who underwent radiosurgery, 2020 patients (27%) harbored cerebral metastases. Eighteen of 2020 patients (0.9%) underwent subsequent craniotomy for tumor removal anywhere from 1 month to 59 months after they received high-dose irradiation. Histologic and immunohistochemical investigations were performed on the surgically resected tissue specimens. These specimens were within the radiosurgical treatment volume of the metastatic tumor. RESULTS: Light microscopy revealed 3 basic categories of histologic responses: acute-type, subacute-type, and chronic-type tissue reactions. A moderate-to-intense inflammatory cell reaction was seen in the tissue responses of well controlled neoplasms (i.e., in patients who had neoplasms that required craniotomy for recurrent disease > 5 months after SRS), whereas the inflammatory reaction was missing or sparse in poorly controlled neoplasms (patients who required craniotomy for recurrent disease < 5 months after SRS). This reaction was seen within the irradiated tumor volume and not in the peritumoral area nor in areas remote from the radiosurgical treatment volume. Immunohistochemical characterization demonstrated the presence of prominent CD68-positive macrophage and CD3-positive T-lymphocyte populations. A progressively severe vasculopathy also was observed with increasing time after radiosurgery. CONCLUSIONS: Although causality has not been established, a brisk inflammatory response and more severe vasculopathy were observed in lesions in which recurrences were more delayed.