Progress in neurological surgery最新文献

Gliomas are the most common type of brain cancer in the pediatric patients, constituting about 50% of all childhood intracranial tumors. This is a highly heterogeneous group, varying from the benign WHO histopathological grades I and II to malignant WHO grades III and IV. The histology and location are significant prognostic factors, which influence the decision for surgical intervention, as well as the extent of possible tumor removal. In low-grade gliomas, surgery remains the initial option and should be directed at gross total resection in favorable locations, such as the cerebral hemispheres and the cerebellum. Management of high-grade gliomas (HGG), which are less common in children compared to adults, continue to pose a significant challenge. In non-brainstem HGG, the goal is safe maximal tumor removal, while it generally does not play any role in diffuse intrinsic pontine gliomas. Treatment must, thus, be individualized in the majority of cases of HGG. Surgery for gliomas in children continues to be aided by technological advancements facilitating tumor resection and improving patient safety and outcomes.

Laser-induced interstitial thermotherapy (LITT) is a modern minimally invasive treatment modality applied for management of a variety of diseases. Recent developments of techniques for precise targeting of the lesion, accurate delivery of the prescribed therapeutically effective thermal doses, and real-time visualization of the induced tissue damage during the procedure by means of intraoperative MR thermometry have stimulated a number of clinical studies testing LITT in cases of different brain pathologies, including gliomas. This modality is particularly attractive in patients with recurrent, deep-seated, and/or critically located neoplasms refractory to other treatments, where it can effectively demonstrate improvement of prognosis providing high quality of life and eliminating the risks of open tumor resection. Low morbidity rates associated with LITT and short hospital stay result in decreased cost of hospitalization. The effectiveness of thermal therapies, particularly after long-term follow-up, still needs evaluation in carefully planned randomized clinical trials, whereas elucidating the effects of laser treatment at the molecular, cellular, and organic levels will continue to expand the boundaries of its clinical applicability in neuro-oncology.

Management options for residual or recurrent glioblastoma multiforme (GBM) are limited despite advances in surgical, chemotherapeutic, and radiotherapeutic techniques. Stereotactic radiosurgery (SRS) is often beneficial in such cases providing improved survival of patients, but still remains underutilized as part of the multimodality management of malignant gliomas. During the last 20 years, 297 patients with histologically proven residual or recurrent GBM underwent Gamma Knife surgery in the University of Pittsburgh. Retrospective analysis of outcomes revealed median survival after initial diagnosis of 18 months, and 1- and 2-year survival rates of 72.5 and 29.5%, respectively. Median survival from the time of SRS was 9 months. The use of modified RPA (recursive partitioning analysis) classification demonstrated superior survival in our series in comparison with historical data. Important prognostic variables include tumor volume <14 cm3, marginal radiation dose of ≥15 Gy, and younger age of the patients (<60 years). Adverse radiation effects (ARE) were noted in 23% of cases and were mainly controlled with corticosteroids. Combining SRS with bevacizumab resulted in further improvement of the overall and progression-free survival and decreased incidence of ARE. Nevertheless, for future application of SRS in patients with GBM, evaluation of its efficacy in a well-designed prospective controlled clinical trials seems mandatory.

Attainment of local control is a cornerstone in the management of brain tumors in children. Treatment of progressive low-grade and all high-grade gliomas traditionally includes resection followed by fractionated radiotherapy (FRT) or FRT alone in neoplasms not amenable to surgical removal. While in younger children chemotherapy is typically used as a first-line non-surgical management option, FRT in such patients remains the standard of salvage therapy. Recent improvements in techniques for radiation treatment planning and delivery allow conformal and selective coverage of the target volume with a prescribed dose, sparing adjacent normal tissues to assure maximal tumor control and minimal toxicity. Implementation of novel functional and metabolic neuroimaging allows better delineation of the lesion margins and organs at risk, which also reduces the incidence of adverse effects. Further improvements of outcome after radiation treatment of pediatric gliomas may be expected with wider application of intensity-modulated radiation therapy (IMRT), proton therapy, and stereotactic techniques, including brachytherapy.

Surgical resection of gliomas affecting functionally important brain structures is associated with high risk of permanent postoperative neurological deficit and deterioration of the patient's quality of life. The availability of modern neuroimaging and neuronavigation permits the application of minimally invasive stereotactic cryodestruction of the tumor in such cases. The authors used this treatment in 88 patients with supratentorial gliomas of various WHO histopathological grades not suitable for microsurgical resection. Postoperative mortality (1.1%) and rate of surgical complications (11.4%) were comparable to reported results of stereotactic brain tumor biopsy, whereas the rate of neurological morbidity (42%) was comparable to outcome after resection of gliomas within eloquent brain areas. The majority of complications were temporary, and permanent deterioration of neurological function was noted in 8% of cases only. The median survival after treatment in patients with glioblastoma and anaplastic astrocytoma was 12.4 and 46.9 months, respectively, and was not reached in cases of diffuse astrocytoma, which compared favorably both with historical controls and literature data. Therefore, it seems reasonable to consider stereotactic cryodestruction in multimodality management strategies of "unresectable" intracranial gliomas, and further studies directed at evaluation of its efficacy are definitely needed.

Multiple alterations in the expression levels of genes or proteins have been identified in gliomas, including activation of oncogenes and silencing of tumor suppressor genes. Illuminating these molecular mechanisms of tumorigenesis and treatment resistance is necessary for the development of new therapies. With the promise of better effectiveness and less toxicity, the emphasis in drug development has moved from cytotoxic, non-specific chemotherapies to molecular targeted agents. However, despite progress in other areas of oncology, targeted therapy success stories in cases of brain tumors remain all but absent. Nonetheless, experiences from previous clinical trials suggest that a small number of unselected patients may benefit from such treatment. An increasing knowledge about related factors and prospective enrichment strategies now shape research and clinical trial design in neuro-oncology and may lead to improved outcomes after molecular targeted therapies of gliomas.

Deep brain stimulation (DBS) has been widely accepted as a tool for treating many symptoms of Parkinson's disease (PD); pallidotomy has been nearly abandoned. Concerns about both the safety and efficacy of pallidotomy are based on small series, isolated case reports, and techniques that would now be considered obsolete. The senior author recently reviewed long-term follow-up of a series of patients who had gamma knife pallidotomy (GKP) for advanced PD. GKP leads to durable, clinically significant benefit. Bilateral GKP adds incremental improvement. The complication rate was 4% when calculated on a per lesion basis. GKP is not quite as effective as DBS for tremor and bradykinesia; the results of GKP and DBS are equivalent for dyskinesia. GKP should be considered in patients who are not candidates for DBS. GKP is not as invasive as radiofrequency pallidotomy and avoids the problems and expenses associated with DBS. Patients on anticoagulants, with cognitive deficits or with other contraindications to DBS can be offered GKP to alleviate many of the motor symptoms of PD.

Great progress has been made in expanding our understanding of the natural history of movement disorders, leading to impressive advancements in their medical and surgical management. Movement disorders are a diverse group of diseases, varying widely in clinical characteristics and evolution. Some are monosymptomatic while others have associated motor and nonmotor features. Some are static while others follow a progressive course. This chapter will review common primary and secondary movement disorders: Parkinson disease and other forms of Parkinsonism, essential tremor and its differential diagnoses, dystonia and tic disorders. Herein, we will provide an overview of the clinical presentation and prognosis of the primary and secondary movement disorders most relevant to discussions of surgical candidacy.

Despite many recent advances in the management of gliomas, such as aggressive surgical resection, chemoradiotherapy, antiangiogenic therapy, and molecular targeted therapy, the survival of patients with high-grade neoplasms remains dismal. Gene therapy and oncolytic virotherapy have emerged as highly promising strategies for treatment of malignant brain tumors due to recent progress in understanding of the underlying cancer biology as well as improved techniques for genetic modification of potential therapeutics.

The use of deep brain stimulation (DBS) of the thalamus has been proven to be a safe and efficacious treatment for the management of many diseases. The most common indication for thalamic DBS remains essential tremor (ET), one of the most common movement disorders in the world. ET patients should be considered for surgical intervention when their tremor has demonstrated to be refractory to medication, a characteristic estimated to be present in roughly 50% of ET cases. Advantages of DBS over thalamotomy include its reversibility, the ability to adjust stimulation settings to optimize efficacy and minimize side effects, the ability to perform bilateral procedures safely, and an association with a lower risk of postoperative cognitive problems. The most common target of DBS for ET is the ventralis intermedius (VIM) of the thalamus, and the optimal electrode location corresponds to the anterior margin of the VIM. Other indications for thalamic DBS include non-ET tremor, obsessive-compulsive disorder, neuropathic pain, traumatic brain injury, Tourette's syndrome, and drug-resistant epilepsy among others.