Neurosurg Focus
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Comparative Study
Multimodal navigation in the functional microsurgical resection of intrinsic brain tumors located in eloquent motor areas: role of tractography.
Nowadays the role of microsurgical management of intrinsic brain tumors is to maximize the volumetric resection of the tumoral tissue, minimizing the postoperative morbidity. The purpose of this paper was to study the benefits of an original protocol developed for the microsurgical treatment of tumors located in eloquent motor areas where the navigation and electrical stimulation of motor subcortical pathways have been implemented. ⋯ The integration of anatomical and functional studies allows a safe functional resection of the brain tumors located in eloquent areas. Multimodal navigation allows integration and correlation among preoperative and intraoperative anatomical and functional data. Cortical motor functional areas are anatomically and functionally located preoperatively thanks to MR and fMR imaging and subcortical motor pathways with DT imaging and tractography. Intraoperative confirmation is done with CS and N20 inversion wave for cortical structures and with sCS for subcortical pathways. With this protocol the authors achieved a good volumetric resection in cortical and subcortical tumors located in eloquent motor areas, with an increase in the incidence of neurological deficits in the immediate postoperative period that significantly decreased 1 month later. Ongoing studies must define the safe limits for functional resection, taking into account the intraoperative brain shift. Finally, it must be demonstrated whether this protocol has any long-term benefit for patients by prolonging the disease-free interval, the time to recurrence, or the survival time.
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Patients with symptomatic pathological compression fractures require spinal stabilization surgery for mechanical back pain control and radiation therapy for the underlying malignant process. Spinal radiosurgery provides excellent long-term radiographic control for vertebral metastases. Percutaneous cement augmentation using polymethylmethacrylate (PMMA) may be contraindicated in lesions with spinal canal compromise due to the risk of displacement of tumor resulting in spinal cord or cauda equina injury. However, there is also significant morbidity associated with open corpectomy procedures in patients with metastatic cancer, especially in those who subsequently require adjuvant radiotherapy. This study evaluated a treatment paradigm for malignant vertebral compression fractures consisting of transpedicular coblation corpectomy combined with closed fracture reduction and fixation, followed by spinal radiosurgery. ⋯ There were no complications associated with any part of the procedure. Adequate cement augmentation within the vertebral body was achieved in all cases. The mean radiosurgical tumor dose was 19 Gy covering the entire vertebral body. The procedure provided long-term pain improvement and radiographic tumor control in all patients (follow-up range 7-44 months). No patient later required open surgery. No radiation-induced toxicity or new neurological deficit occurred during the follow-up period. CONCLUSIONS This treatment paradigm for pathological fractures of percutaneous transpedicular corpectomy combined with cement augmentation followed by radiosurgery was found to be safe and clinically effective. This technique combines minimally invasive procedures that avoid the morbidity associated with open surgery while providing spinal canal decompression and immediate fracture stabilization, and then administering a single-fraction tumoricidal radiation dose.
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Glioblastoma multiforme (GBM) is a devastating malignant brain tumor characterized by resistance to available therapeutic approaches and relentless malignant progression that includes widespread intracranial invasion, destruction of normal brain tissue, progressive disability, and death. Stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (fSRT) are increasingly used in patients with recurrent GBM to complement traditional treatments such as resection, conventional external beam radiotherapy, and chemotherapy. ⋯ In addition, state-of-the-art neuroimaging techniques, such as MR spectroscopic imaging, diffusion tensor tractography, and nuclear medicine imaging, have enhanced treatment planning methods leading to potentially improved clinical outcomes. In this paper the authors reviewed the current applications and efficacy of SRS and fSRT in the treatment of GBM, highlighting the value of these therapies for recurrent focal disease.
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Comparative Study
Evaluation of hearing function after Gamma Knife surgery of vestibular schwannomas.
Due to technological advances in neuroradiology in recent years, incidental diagnoses of vestibular schwannomas (VSs) have increased. The aim of this study was to evaluate the hearing function after treatment with Gamma Knife surgery (GKS) for VSs in patients adequately selected with "good" or "useful" hearing before treatment and to assess the possible predictive factors for hearing function preservation. ⋯ The results of the study show that the probability of preserving functional hearing in patients undergoing GKS treatment for unilateral VSs is very high. Patients with GR Class I, age younger than 54 years, with presenting symptoms other than hearing loss, and a Koos Stage T1 tumor have better prognosis. The prescribed dose of 13 Gy appears to represent an excellent compromise between controlling the disease and preserving auditory function.
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Whole-brain radiation therapy (WBRT) has been the traditional approach to minimize the risk of intracranial recurrence following resection of brain metastases, despite its potential for late neurotoxicity. In 2007, the authors demonstrated an equivalent local recurrence rate to WBRT by using stereotactic radiosurgery (SRS) to the operative bed, sparing 72% of their patients WBRT. They now update their initial experience with additional patients and more mature follow-up. ⋯ Adjuvant SRS to the metastatic intracranial operative bed results in a local recurrence rate equivalent to adjuvant WBRT. In combination with SRS for unresected lesions and routine imaging surveillance, this approach achieves robust overall survival (median 15 months) while sparing 70% of the patients WBRT and its potential acute and chronic toxicity.