Progress in neurological surgery
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Although commonly used in clinical practice, peripheral nerve stimulation (PNS) for treatment of chronic pain is performed mainly with devices developed and marketed for spinal cord stimulation applications. This may be one of the reasons why PNS approach is marked by a very high complication rate, as the anatomy of peripheral nerves and the surrounding soft tissues is quite different from epidural spinal space for which the current devices are designed. ⋯ Based on the literature data and the analysis of the author's experience with PNS procedures it appears that although the rate of complications is relatively high, the morbidity associated with PNS approach is very minor and most problems may be resolved with simple re-operations, usually on outpatient basis. The reduction in complication rate is expected to occur when the hardware used in PNS procedures is appropriately adapted for PNS applications.
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Recent research has highlighted the important role of the sphenopalatine ganglion (SPG) in cerebrovascular autonomic physiology and in the pathophysiology of cluster and migraine headaches as well as conditions of stroke and cerebral vasospasm. The relatively accessible location of the SPG within the pterygopalatine fossa and the development of options for minimally invasive approaches to the SPG make it an attractive target for neuromodulation approaches. The obvious advantage of SPG stimulation compared to ablative procedures on the SPG such as radiofrequency destruction and stereotactic radiosurgery is its reversibility and adjustable features. The on-going design of strategies for transient and continuous SPG stimulation on as needed basis using implantable SPG stimulators is an exciting new development which is expected to expand the clinical versatility of this technique.
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Gamma knife (GK) thalamotomy for functional disorders, primarily Parkinson disease and central pain, are described herein. The goal was to extend our present indications for selective thalamotomy. Our target for tremor surgery is about 45% of the thalamic length. ⋯ In most of our cases, the protocol was 130 Gy, delivered in one shot with a 4-mm collimator. The time courses of thalamic lesion changes and clinical improvement after irradiation were assessed. Thus, despite thalamic reaction changes being variable, we achieved a clinical success rate of approximately 80% with negligible complications.
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The purpose of this study was to analyze tumor control and possible complications of gamma knife radiosurgery (GKRS) in patients with vestibular schwannomas using low marginal doses and conformal multiple shots to fit irregular tumor shapes. The authors evaluated 152 patients with more than 5 years of follow-up. Marginal doses were 9-15 Gy (median 12 Gy), with corresponding treatment volumes ranging from 0.1 to 18.7 cm3 (median 2.0 cm3). ⋯ Hydrocephalus was recognized in 5.3% of all patients, and tended to occur in cases with larger tumors (p = 0.0024). GKRS provides a safe and effective therapy for small to medium-sized tumors. However, indications for larger tumors must be carefully considered, as they are more difficult to control and liable to produce ataxia due to transient expansion.
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One of the earliest indications for Gamma Knife treatment, radiosurgery for cerebral arteriovenous malformations, has stood the test of time. While initially only the ideal cases (small, compact nidus in a non-eloquent site) were chosen, increasingly larger, more complex AVMs were treated. Combination treatment with embolisation and surgery enables most lesions to be treated with success and remarkably low complication rate. This paper is a brief overview of the experience gained in Sheffield.