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Background Despite the development of effective pharmacologic and cognitive behavioral treatments for obsessive-compulsive disorder (OCD), some patients continue to be treatment-refractory and severely impaired. Fiber tracts connecting orbitofrontal and dorsal anterior cingulate cortex with subcortical nuclei have been the target of neurosurgical lesions as well as deep brain stimulation in these patients. We report on the safety and efficacy of ventral gamma capsulotomy for patients with intractable OCD. Methods Fifty-five patients with severely disabling, treatment-refractory OCD received bilateral lesions in the ventral portion of the anterior limb of the internal capsule over a 20-year period using the Leksell Gamma Knife. The patients were prospectively followed over 3 years with psychiatric, neurologic, and neuropsychological assessments of safety and efficacy, as well as structural neuroimaging. Results Thirty-one of 55 patients (56%) had an improvement in the primary efficacy measure, the Yale-Brown Obsessive Compulsive Scale, of ≥35% over the 3-year follow-up period. Patients had significant improvements in depression, anxiety, quality of life, and global functioning. Patients tolerated the procedure well without significant acute adverse events. Five patients (9%) developed transient edema that required short courses of dexamethasone. Three patients (5%) developed cysts at long-term follow-up, 1 of whom developed radionecrosis resulting in an ongoing minimally conscious state. Conclusions Gamma Knife ventral capsulotomy is an effective radiosurgical procedure for many treatment-refractory OCD patients. A minority of patients developed cysts at long-term follow-up, 1 of whom had permanent neurological sequelae.

Background Neurosurgeries such as gamma ventral capsulotomy (GVC) are an option for otherwise intractable obsessive-compulsive disorder (OCD) patients. In general, clinical and neuropsychological status both improve after GVC. However, its consequences on personality traits are not well-studied. The objective of this study was to investigate personality changes after one year of GVC in intractable OCD patients. Methods The personality assessment was conducted using the Revised NEO Personality Inventory (NEO PI-R) and Cloninger's Temperament and Character Inventory (TCI) in 14 intractable OCD patients before and one year after GVC. Comparisons of personality features between treatment responders (n = 5) and non-responders (n = 9) were performed. Multiple linear regression was also used for predicting changes in clinical and global functioning variables. Results Overall, no deleterious effect was found in personality after GVC. Responders had a reduction in neuroticism (p = 0.043) and an increase in extraversion (p = 0.043). No significant changes were observed in non-responders. Increases in novelty seeking and self-directedness, and decreases in persistence and cooperativiness predicted OCD symptom improvement. Similary, improvement in functioning was also predicted by hgher novelty seeking and self-directedness after GVC, whereas better functioning was also associated with lower reward dependence and cooperativeness after surgery. Conclusions The pattern of changes in personality traits after GVC was generally towards that observed in nonclinical population, and does not raise safety concerns.

Object The goal of this study was to evaluate outcomes in patients with ≥ 10 CNS metastases treated with Gamma Knife stereotactic radiosurgery (GK-SRS). Methods Patients with ≥ 10 brain metastases treated using GK-SRS during the period between 2004 and 2010 were identified. Overall survival and local and regional control as well as necrosis rates were determined. The influence of age, sex, histological type, extracranial metastases, whole-brain radiation therapy, and number of brain metastases was analyzed using the Kaplan-Meier method. Univariate (log-rank) analyses were performed, with a p value of < 0.05 considered significant. Results Fifty-three patients with ≥ 10 brain metastases were treated between 2004 and 2010. All had a Karnofsky Performance Status score of ≥ 70. Seventy-two percent had either non–small cell lung cancer (38%) or breast cancer (34%); melanoma, small cell lung cancer, renal cell carcinoma, and testicular, colon, and ovarian cancer contributed the remaining 28%. On average, 10.9 lesions were treated in a single session. Sixty-four percent of patients received prior whole-brain radiation therapy. The median survival was 6.5 months. One-year overall survival was 42% versus 14% when comparing breast cancer and other histological types, respectively (p = 0.074). Age, extracranial metastases, number of brain metastases, and previous CNS radiation therapy were not significant prognostic factors. Although the median time to local failure was not reached, the median time to regional failure was 3 months. Female sex was associated with longer time to regional failure (p = 0.004), as was breast cancer histological type (p = 0.089). No patient experienced symptomatic necrosis. Conclusions Patients with ≥ 10 brain metastases who received prior CNS radiation can safely undergo repeat treatment with GK-SRS. With median survival exceeding 6 months, aggressive local treatment remains an option; however, rapid CNS failure is to be expected. Although numbers are limited, patients with breast cancer represent one group of individuals who would benefit most, with prolonged survival and extended time to CNS recurrence.

For more than half a century, stereotactic neurosurgical procedures have been available to treat patients with severe, debilitating symptoms of obsessive-compulsive disorder (OCD) that have proven refractory to extensive, appropriate pharmacological, and psychological treatment. Although reliable predictors of outcome remain elusive, the establishment of narrower selection criteria for neurosurgical candidacy, together with a better understanding of the functional neuroanatomy implicated in OCD, has resulted in improved clinical efficacy for an array of ablative and non-ablative intervention techniques targeting the cingulum, internal capsule, and other limbic regions. It was against this backdrop that gamma knife capsulotomy (GKC) for OCD was developed. In this paper, we review the history of this stereotactic radiosurgical procedure, from its inception to recent advances. We perform a systematic review of the existing literature and also provide a narrative account of the evolution of the procedure, detailing how the procedure has changed over time, and has been shaped by forces of evidence and innovation. As the procedure has evolved and adverse events have decreased considerably, favorable response rates have remained attainable for approximately one-half to two-thirds of individuals treated at experienced centers. A reduction in obsessive-compulsive symptom severity may result not only from direct modulation of OCD neural pathways but also from enhanced efficacy of pharmacological and psychological therapies working in a synergistic fashion with GKC. Possible complications include frontal lobe edema and even the rare formation of delayed radionecrotic cysts. These adverse events have become much less common with new radiation dose and targeting strategies. Detailed neuropsychological assessments from recent studies suggest that cognitive function is not impaired, and in some domains may even improve following treatment. We conclude this review with discussions covering topics essential for further progress of this therapy, including suggestions for future trial design given the unique features of GKC therapy, considerations for optimizing stereotactic targeting and dose planning using biophysical models, and the use of advanced imaging techniques to understand circuitry and predict response. GKC, and in particular its modern variant, gamma ventral capsulotomy, continues to be a reliable treatment option for selected cases of otherwise highly refractory OCD.

Purpose Optimal patient selection for stereotactic radiosurgery (SRS) as the initial treatment for brain metastases is complicated and controversial. This study aimed to develop a nomogram that predicts survival without salvage whole brain radiation therapy (WBRT) after upfront SRS. Methods and Materials Multi-institutional data were analyzed from 895 patients with 2095 lesions treated with SRS without prior or planned WBRT. Cox proportional hazards regression model was used to identify independent pre-SRS predictors of WBRT-free survival, which were integrated to build a nomogram that was subjected to bootstrap validation. Results Median WBRT-free survival was 8 months (range, 0.1-139 months). Significant independent predictors for inferior WBRT-free survival were age (hazard ratio [HR] 1.1 for each 10-year increase), HER2(−) breast cancer (HR 1.6 relative to other histologic features), colorectal cancer (HR 1.4 relative to other histologic features), increasing number of brain metastases (HR 1.09, 1.32, 1.37, and 1.87 for 2, 3, 4, and 5+ lesions, respectively), presence of neurologic symptoms (HR 1.26), progressive systemic disease (HR 1.35), and increasing extracranial disease burden (HR 1.31 for oligometastatic and HR 1.56 for widespread). Additionally, HER2(+) breast cancer (HR 0.81) and melanoma (HR 1.11) trended toward significance. The independently weighted hazard ratios were used to create a nomogram to display estimated probabilities of 6-month and 12-month WBRT-free survival with a corrected Harrell's C concordance statistic of 0.62. Conclusions Our nomogram can be used at initial evaluation to help select patients best suited for upfront SRS for brain metastases while reducing expense and morbidity in patients who derive minimal or no benefit.

Five refractory obsessive-compulsive patients were assessed using a neuropsychological battery after a modified gamma knife capsulotomy. The surgical technique was not associated with profound cognitive deficits. The authors found improvements in attention, vocabulary, learning, abstract reasoning, and memory.

Object The response rate of vestibular schwannomas (VSs) to radiosurgery has reached the 97% level in several published series. When failure rarely occurs, some controversy has existed as to whether the tumor has to be resected or can be safely retreated with radiosurgery. The authors retrospectively studied the outcome of retreating 11 patients with Gamma Knife surgery (GKS). Methods The authors studied 11 patients at the New England Gamma Knife Center who had undergone GKS as a second radiosurgical treatment for VS from 1994 to 2007. One patient underwent proton-beam radiotherapy as the first treatment, and the other 10 patients had undergone GKS initially. Tumor control (size before and after the first and the second treatment) was evaluated using MR imaging to demonstrate the course after the 2 treatments. Facial nerve function (House–Brackmann grading system), trigeminal nerve function, hearing (Gardner–Robertson classification), and any adverse radiation effects were evaluated. The prescription dose was 12 Gy (11–13.2 Gy) for both treatments. Results Of the 11 patients, 2 showed increase, 1 had no change, and, in 8, the VS decreased in size after the retreatment. One tumor remained unchanged over the first 6 months, but demonstrated signs of internal necrosis. All patients demonstrated stable facial nerve function. Regarding facial numbness, 2 patients experienced increases, 8 no change, and 1 decreased numbness. There was no functional hearing prior to the second treatment in 10 patients, and hearing was impaired in 1 patient. Adverse radiation effects (slight peduncular edema) were seen in 2 patients after the second treatment, and 1 patient had edema after the first treatment as well. Conclusions Vestibular schwannomas can be retreated with GKS with good tumor control response and low risk of toxicity.

ObjectGamma Knife surgery (GKS) is often the sole treatment for brain metastases. The authors hypothesized that early post-GKS measures of the relative apparent diffusion coefficient (rADC) could predict therapeutic response, recurrence, and radionecrosis prior to changes in tumor volume.MethodsMagnetic resonance (MR) images of 25 metastatic tumors in 15 patients were reviewed. Inclusion criteria included a history of surgery or GKS, a minimum tumor diameter of 5 mm at treatment, and a minimum of two follow-up MR images. Tumor volumes were normalized to baseline, and tumor ADC values were normalized to normal-appearing white matter (rADC). A successful therapeutic response (STR) was defined by a monotonically decreasing tumor volume throughout the follow-up period. Magnetic resonance spectroscopy was used to classify non-STRs as radionecrosis or tumor recurrence.All tumors exhibited a decreased normalized volume (mean 37%) at the first follow-up examination (range 33–124 days after GKS, mean 54 days), and three distinct rADC patterns subsequently evolved: Group 1 (STR [10 cases]), monotonically decreasing volume with gradually increasing rADC; Group 2 (radionecrosis [three cases]), initial volume reduction followed by gradual increase, with initial rapidly increasing rADC followed by more gradual increase or plateau; and Group 3 (recurrent tumor [12 cases]), initial volume decrease followed by increase, with a preceding gradual decrease in the rADC.Conclusions The rADC patterns outperform initial post-GKS tumor volume in predicting the long-term response to treatment. Decreasing tumor volume with an increasing rADC predicts an STR. For lesions with increasing volume, antecedent rADC reduction predicts recurrence, whereas a rapidly increasing rADC predicts radionecrosis. Evaluation of the rADC at the initial post-GKS follow-up examination appears to be a useful prognostic measure of metastatic tumor response.

The purpose of this study was to determine the prevalence of hydrocephalus in patients with vestibular schwannoma. A second objective was to investigate possible etiologies for hydrocephalus in this population by attempting to correlate the incidence and severity of hydrocephalus with tumor volume and extent of fourth ventricular compression. The MRI examinations of 157 adult patients with vestibular schwannoma were retrospectively reviewed. Tumor size was quantified, and the presence of accompanying hydrocephalus was assessed, categorized as communicating type or non-communicating type and then rated as mild, moderate or severe (grades 1-3). Next, the degree of fourth ventricular distortion caused by tumor mass effect was evaluated and categorized as mild, moderate or severe (grades 1-3). Spearman's rank correlation coefficient was used to test the relationships between tumor volume and (1) the extent of fourth ventricular effacement and (2) severity of hydrocephalus. Hydrocephalus was present in 28/157 (18%) cases and was categorized as mild in 11/28 (39%), moderate in 15/28 (54%) and severe in 2/28 (7%). Communicating-type hydrocephalus was present in 17/28 (61%) and non-communicating type in 11/28 (39%). There was a positive correlation between the grade of non-communicating hydrocephalus and tumor volume (r=0.38; P

Object.The authors undertook a study to identify magnetic resonance (MR) imaging techniques that can be used reliably during gamma knife surgery (GKS) to identify the trigeminal nerve, surrounding vasculature, and areas of compression.Methods.Preoperative visualization of the trigeminal nerve and surrounding vasculature as well as targeting the area of vascular compression may increase the effectiveness of GKS for trigeminal neuralgia. During the past years our gamma knife centers have researched different MR imaging sequences with regard to their ability to visualize cranial nerves and vascular structures. Constructive interference in steady-state (CISS) fusion imaging with three-dimensional gradient echo sequences (3D-Flash) was found to be of greatest value in the authors' 25 most recent patients.In 24 (96%) out of the 25 patients, the fifth cranial nerve, surrounding vessels, and areas of compression could be reliably identified using CISS/3D-Flash. The MR images were acceptable despite patients' history of microvascular decompression, radiofrequency (RF) ablation, or concomitant disease. In one of 25 patients with a history of multiple RF lesions, the visualization was inadequate due to severe trigeminal nerve atrophy.Conclusions.The CISS/3D-Flash fusion imaging has become the preferred imaging method at the authors' institutions during GKS for trigeminal neuralgia. It affords the best visualization of the trigeminal nerve, surrounding vasculature, and the precise location of vascular compression.

Intractable OCD and depression cause tremendous suffering in those affected and in their families. The impaired ability to function of those affected imposes a heavy burden on society as a whole. Existing data suggest that lesion procedures offer benefit to a large proportion (ranging from about 35%-70%) of patients with intractable OCD and depression. The literature also suggests that although serious long-term adverse events have occurred, these are relatively infrequent overall. Methodologic limitations of the earlier reports on any of these procedures were described previously in this article. The major academic centers conducting this work have since been obtaining systematic prospective data using modern assessment tools. Nevertheless, even with improved methodologies, more recent studies confront some remaining issues that have been difficult to overcome fully. First, the number of patients who have received any one procedure has been relatively small, constraining statistical power. This limits the ability of researchers to enhance patient selection based on clinical characteristics. This is important, because patients with intractable OCD and depression referred for neurosurgery have high rates of comorbid Axis I diagnoses, personality disorders, and functional impairments, which may have value in predicting response. Other features, such as age of onset, chronicity, and symptom subtypes, may be likewise useful. Another key factor in response may be postoperative management, which has varied most over time but also across patients enrolled in trials. As noted previously, randomized controlled trials of neurosurgical treatment for intractable psychiatric illness have not been reported, although one has been proposed for gamma knife capsulotomy in intractable OCD [23]. The development of deep brain stimulation has also made sham-controlled studies possible and also allows within-patient designs to be considered. Bearing these problems in mind, the literature does provide important guidance on a number of key points, including approaches to referral, patient selection, and the need for long-term prospective follow-up and postoperative management. Nevertheless, important gaps in knowledge remain in all these areas. Research is expected to narrow these gaps in a number of ways, including patient selection, optimizing the procedures themselves, and understanding the mechanisms of therapeutic action. Neuroimaging studies will play a key role in achieving these aims (see the article by Rauch in this issue). So will cross-species translational research on the anatomy and physiology of the pathways implicated in the pathophysiology and response to treatment in these disorders. Future research in psychiatric neurosurgery must proceed cautiously. A recent editorial statement of the OCD-DBS Collaborative Group [26] recommends a minimum set of standards for any multidisciplinary teams contemplating work in this domain. The rationale for those standards is found throughout this issue and is especially developed in the article by Fins. The need for safe and effective therapeutic options for people suffering with these severe illnesses is just as clear. The experience over the last several decades provides grounds for careful optimism that refined lesion procedures or reversible deep brain stimulation may relieve suffering and improve the lives of people with these devastating disorders.

Purpose: To determine the cause of epilation at the top of the head for 2 patients with acoustic neuromas after undergoing fractionated radiosurgery with the Leskell Gamma Knife model C. This epilation was unexpected, because the treatment planning program stated the dose at this location was Methods and Materials: The radiation dose along a central axis, parallel to the couch, from the helmet's focus to the helmet cap was measured during couch transit. Results: Transit doses of 4.4 cGy/shot at 10 cm and 5.6 cGy/shot at distances >15 cm from the helmet's focus were measured. It was estimated that the 2 patients with epilation received approximately 6–7 Gy to the scalp. A shield was constructed and shown to reduce the transit dose by as much as 60%. Conclusion: The design of the helmet allows the uncollimated beams to reach areas of the patient, superior to the target, just before and after couch docking with the housing. For treatment involving a large number of shots (i.e., fractionation), off-target doses ≤8 Gy can result. For these cases, the transit dose should be considered and some form of additional shielding should be used.

Gamma ventral capsulotomy (GVC) radiosurgery is intended to minimize side effects while maintaining the efficacy of traditional thermocoagulation techniques for the treatment of refractory obsessive–compulsive disorder (OCD). Neuropsychological outcomes are not clear based on previous studies and, therefore, we investigated the effects of GVC on cognitive and motor performance. A double-blind, randomized controlled trial (RCT) was conducted with 16 refractory OCD patients allocated to active treatment (n=8) and sham (n=8) groups. A comprehensive neuropsychological evaluation including intellectual functioning, attention, verbal and visuospatial learning and memory, visuospatial perception, inhibitory control, cognitive flexibility, and motor functioning was applied at baseline and one year after the procedure. Secondary analysis included all operated patients: eight from the active group, four from the sham group who were submitted to surgery after blind was broken, and five patients from a previous open pilot study (n=5), totaling 17 patients. In the RCT, visuospatial memory (VSM) performance significantly improved in the active group after GVC (p=0.008), and remained stable in the sham group. Considering all patients operated, there was no decline in cognitive or motor functioning after one year of follow-up. Our initial results after 1 year of follow-up suggests that GVC not only is a safe procedure in terms of neuropsychological functioning but in fact may actually improve certain neuropsychological domains, particularly VSM performance, in treatment refractory OCD patients.

The purpose of this study was to evaluate the response of pituitary adenomas to radiosurgery as manifested by changes in size and appearance on serial MR imaging.Over a mean follow-up period of 36 months, changes in 44 pituitary adenomas were assessed on 147 enhanced MR imaging studies. Prior surgery had been performed in 36 tumors (82%).At the time of radiosurgery, mean tumor volume was 5.9 +/- 0.8 cm(3) (mean diameter, 2.2 cm). The mean reduction in volume at last follow-up was 41% (+/- 5%, p0.001), and a decrease in tumor volume of 25-100% was observed in 34 tumors (77%). Mean reduction in tumor volume at 6 months after radiosurgery was 9% (p = 0.095); at 1 year, 24% (p0.001); at 2 years, 34% (p0.001); at 3 years, 41% (p0.001); and at 4 years, 50% (p = 0.008). Six months after radiosurgery a slight and transient increase in size was observed in 21% of tumors. During follow-up, neither decreased contrast enhancement nor cyst development was associated with changes in tumor volume.Tumor control was observed for most pituitary adenomas after radiosurgery and occurred gradually over a period of several years. A small increase in tumor size might be observed in the first 6 months after radiosurgery. In most cases, reductions in tumor size were not accompanied by a change in contrast enhancement or cyst formation.

Object. The authors review the first series of 10 cases in which injured intraspinal brachial plexus were surgically repaired. They describe the technique of spinal cord implantation or repair of ruptured nerve roots, as well as patient outcome. Methods. Spinal root repair/implantation was performed from 10 days to 9 months postinjury. There were nine male patients and one female patient. Postoperatively in most cases, regeneration of motor neurons from the spinal cord to denervated muscles could be demonstrated. The first signs of regeneration were noted approximately 9 to 12 months postoperatively. Useful function with muscle power of at least Medical Research Council Grade 3 occurred in three of 10 cases. Magnetic brain stimulation studies revealed a normal amplitude and latency from the cortex to reinnervated muscles on surgically treated and control sides. A certain degree of cocontraction between antagonistic muscles (for example, biceps—triceps) compromised function. With time there was a reduction of cocontractions, probably due to spinal cord plasticity. In these cases there was also, surprisingly, a return of sensory function, although the mechanism by which this occurred is uncertain. Sensory stimulation (thermal and mechanical) within the avulsed dermatomes was perceived abnormally and/or experienced at remote sites. There was some return of patients' sense of joint position. Conclusions. A short time lag between the accident and the surgery was recognized as a significant factor for a successful outcome. Reimplantation of avulsed nerve roots may be combined with other procedures such as nerve transfers in severe cases of brachial plexus injury.

Transsphenoidal surgery usually represents first line treatment for pituitary adenomas with the aim of removing the tumor, decompressing the optic apparatus and, in secreting tumors, eliminating the hypersecretion. Gamma Knife radiosurgery is indicated for tumor remnants or recurrences in or above the sella including those invading the cavernous sinus and also as initial treatment in patients who are unable to tolerate an open surgical procedure and where medication has failed. In this study, the target definition was retrospectively studied and when necessary corrected in 10 acromegalic patients, 8 with Cushing's disease, and 12 with prolactinomas undergoing Gamma Knife radiosurgery. The dose plan was analyzed and the volume of the target covered by a minimum of 15, 20, 25, 30 and 35Gy was estimated. A dose/volume profile for each treatment was created and correlated to the endocrinological and clinical outcome. Cure, according to strict endocrinological criteria, was seen in 6 of the acromegalic patients, in 2 of the patients with ACTH hypersecretion, and in 2 of the patients with prolactinomas. Analysis of these profiles, also for the patients with partial effect, show that a minimum radiation dose of 20Gy may be adequate to eliminate the hypersecretion in acromegalic patients whereas a dose of at least 25Gy may be required in patients with Cushing's disease and prolactinoma.

The goal of this study was to evaluate outcomes in patients with ≥ 10 CNS metastases treated with Gamma Knife stereotactic radiosurgery (GK-SRS).Patients with ≥ 10 brain metastases treated using GK-SRS during the period between 2004 and 2010 were identified. Overall survival and local and regional control as well as necrosis rates were determined. The influence of age, sex, histological type, extracranial metastases, whole-brain radiation therapy, and number of brain metastases was analyzed using the Kaplan-Meier method. Univariate (log-rank) analyses were performed, with a p value of0.05 considered significant.Fifty-three patients with ≥ 10 brain metastases were treated between 2004 and 2010. All had a Karnofsky Performance Status score of ≥ 70. Seventy-two percent had either non-small cell lung cancer (38%) or breast cancer (34%); melanoma, small cell lung cancer, renal cell carcinoma, and testicular, colon, and ovarian cancer contributed the remaining 28%. On average, 10.9 lesions were treated in a single session. Sixty-four percent of patients received prior whole-brain radiation therapy. The median survival was 6.5 months. One-year overall survival was 42% versus 14% when comparing breast cancer and other histological types, respectively (p = 0.074). Age, extracranial metastases, number of brain metastases, and previous CNS radiation therapy were not significant prognostic factors. Although the median time to local failure was not reached, the median time to regional failure was 3 months. Female sex was associated with longer time to regional failure (p = 0.004), as was breast cancer histological type (p = 0.089). No patient experienced symptomatic necrosis.Patients with ≥ 10 brain metastases who received prior CNS radiation can safely undergo repeat treatment with GK-SRS. With median survival exceeding 6 months, aggressive local treatment remains an option; however, rapid CNS failure is to be expected. Although numbers are limited, patients with breast cancer represent one group of individuals who would benefit most, with prolonged survival and extended time to CNS recurrence.

✓ Stereotactic radiosurgery (SRS) with the Gamma Knife and linear accelerator has revolutionized neurosurgery over the past 20 years. The most common indications for radiosurgery today are tumors and arteriovenous malformations of the brain. Functional indications such as treatment of movement disorders or intractable pain only contribute a small percentage of treated patients. Although SRS is the only noninvasive form of treatment for functional disorders, it also has some limitations: neurophysiological confirmation of the target structure is not possible, and one therefore must rely exclusively on anatomical targeting. Furthermore, lesion sizes may vary, and shielding adjacent radiosensitive neural structures may be difficult or impossible. The most common indication for functional SRS is the treatment of trigeminal neuralgia. Radiosurgical treatment for epilepsy and certain psychiatric illnesses is performed in several centers as part of strict research protocols, and radiosurgical pallidotomy or medial thalamotomy is no longer recommended due to the high risk of complications. Radiosurgical ventrolateral thalamotomy for the treatment of tremor in patients with Parkinson disease or multiple sclerosis, as well as in the treatment of essential tremor, may be indicated for a select group of patients with advanced age, significant medical conditions that preclude treatment with open surgery, or patients who must receive anticoagulation therapy. A promising new application of SRS is high-dose radiosurgery delivered to the pituitary stalk. This treatment has already been successfully performed in several centers around the world to treat severe pain in patients with end-stage cancer.

Importance Select cases of intractable obsessive-compulsive disorder (OCD) have undergone neurosurgical ablation for more than half a century. However, to our knowledge, there have been no randomized clinical trials of such procedures for the treatment of any psychiatric disorder. Objective To determine the efficacy and safety of a radiosurgery (gamma ventral capsulotomy [GVC]) for intractable OCD. Design, Setting, and Participants In a double-blind, placebo-controlled, randomized clinical trial, 16 patients with intractable OCD were randomized to active (n = 8) or sham (n = 8) GVC. Blinding was maintained for 12 months. After unblinding, sham-group patients were offered active GVC. Interventions Patients randomized to active GVC had 2 distinct isocenters on each side irradiated at the ventral border of the anterior limb of the internal capsule. The patients randomized to sham GVC received simulated radiosurgery using the same equipment. Main Outcomes and Measures Scores on the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) and the Clinical Global Impression-Improvement (CGI-I) Scale at 1 year. Response was defined as a 35% or greater reduction in Y-BOCS severity and “improved” or “much improved” CGI-I ratings. Results Two of 8 patients randomized to active treatment responded at 12 months, and none of the 8 sham-GVC group patients responded (the absolute difference was not statistically significant: 0.25; 95% CI, −0.05 to 0.55; P = .11). At 12 months, median Y-BOCS scores were 23.5 in the active group vs 31 in the sham patients ( P = .01). The median Y-BOCS scores decreased 28.6% in the active treatment group and 5.8% in the sham group ( P = .04988). The median CGI-I scores were 3 and 4 in the active and sham treatment groups, respectively. At 54 months, 3 additional patients in the active group had become responders. Of the 4 sham-GVC patients who later received active GVC, 2 responded by post-GVC month 12. The most serious adverse event was an asymptomatic radiation-induced cyst in 1 patient. Conclusions and Relevance In this preliminary trial, patients with intractable OCD who underwent GVC may have benefitted more than those who underwent sham surgery although the difference did not reach statistical significance. Additional research is necessary to determine if GVC is better than deep-brain stimulation. Trial Registration clinicaltrials.gov Identifier:NCT01004302

✓ Stereotactic radiosurgery is being increasingly advocated as the primary modality for treatment of vestibular schwannomas (VS). This modality has been shown to arrest tumor growth, with few associated short-term morbidities, and with possibly better hearing and facial nerve preservation rates than microsurgery. Radiation-induced oncogenesis has long been recognized, although stereotactic radiosurgery de novo induction of a secondary tumor has never been clearly described. The authors report on a patient with a VS who did not have neurofibromatosis Type 2 and who underwent gamma knife surgery (GKS). This patient required microsurgical removal of the VS within 8 months because of development of a tumor cyst with associated brainstem compression and progressive hydrocephalus. The operation resulted in clinical stabilization and freedom from tumor recurrence. Seven and a half years after undergoing GKS, the patient presented with symptoms of raised intracranial pressure. Magnetic resonance imaging demonstrated a new ring-enhancing lesion in the inferior temporal lobe adjacent to the area of radiosurgery, which on craniotomy was confirmed to be a glioblastoma multiforme (GBM). Despite additional conventional external-beam radiation to the temporal lobe, the GBM has progressed. Whereas this first reported case of a GBM within the scatter field of GKS does not conclusively prove a direct causal link, it does fulfill all of Cahan's criteria for radiation-induced neoplasia, and demands increased vigilance for the potential long-term complications of stereotactic radiosurgery, and reporting of any similar cases.

✓ The authors investigated the use of gamma knife surgery (GKS) in the treatment of central neurocytoma, a usually benign primary brain tumor of the lateral and third ventricles. Four patients with subtotally resected or recurrent central neurocytomas were retrospectively studied. The prescription isodose was 9 to 13 Gy to the 30 to 50% peripheral isodose line. Pre- and postoperative magnetic resonance (MR) images were compared to determine the volume reduction following GKS. Follow-up review included annual MR imaging and clinical evaluation by a neurosurgeon. Follow-up periods ranged from 12 to 99 months. Marked reduction in tumor size was seen in all four patients; the decrease in tumor volume for each was 48%, 72%, 81%, and 77%, respectively, at the last follow-up review. None of the four patients required additional treatment and none experienced a decline in neurological function during the follow-up period. No complications have been noted in any of these patients to date. Even though there have been few observations and follow-up time has been limited, because of the consistency of the response and the lack of observed side effects, GKS may be the treatment of choice for subtotally resected and recurrent central neurocytomas.

Stereotactic radiosurgery with the gamma knife delivers focused radiation from a cobalt-60 source in a single session to a pituitary tumour with minimal radiation to the adjacent normal brain tissue. Currently, gamma knife radiosurgery is predominantly used to treat failed pituitary surgery, although it has a role as a primary treatment for patients unwilling or unsuitable, for medical reasons, to undergo trans-sphenoidal surgery. The major risk from gamma knife radiosurgery is radiation damage to the visual pathways, but this can be avoided by limiting the radiation dose to the optic chiasm to under 10 Gy. In contrast, the neuronal and vascular structures running in the cavernous sinus are much less radiosensitive, allowing an ablative dose to be administered to tumours showing lateral invasion and impinging on cranial nerves III, IV, V and VI. Gamma knife radiosurgery appears to produce remission in secretory tumours faster than fractionated radiotherapy. Furthermore, the potential long-term risk of developing a second extra-pituitary brain tumour, as well as the neuropsychiatric effects associated with conventional radiation administration, seems less likely to occur with this form of treatment.

1. Gamma knife therapy is an effective method of delivering radiation to pituitary tumors that have failed surgery and may be used as primary treatment in circumstances in which the patient refuses or is unsuitable for a transsphenoidal procedure. 2. Stereotactic radiosurgery with the gamma knife unit is generally administered in a single session unlike fractionated radiotherapy, which is administered four to five times per week over a 6-week period. 3. Preliminary data suggest that resolution of pituitary hypersecretion is faster with gamma knife therapy than with conventional radiotherapy. 4. Because of the nature of the gamma knife therapy and the fact that the radiation dose conforms to the tumor shape, there is a steep fall-off of radiation to surrounding tissue. Accordingly, the radiation dose to extrapituitary brain is substantially less with gamma knife radiosurgery than with conventional radiotherapy. This suggests that the development of second brain tumors and neurocognitive complications, which are significant risks with conventional radiotherapy, is much less likely with gamma knife surgery. 5. Gamma knife radiosurgery can be used to ablate tumors invading the cavernous sinus. 6. Gamma knife radiosurgery is safe as long as the dose of radiation to the optic structures is kept under 10 Gy. 7. Long-term follow-up is required for pituitary tumors treated by gamma knife therapy so as to determine its efficacy as well as its effects on pituitary function and any resultant complications.

PURPOSE: To discuss how the evolution of vestibular schwannoma radiosurgery, changes in health care delivery, and patient accessibility to medical information will affect the management of vestibular schwannomas in the future. CONCEPT: In comparison with microsurgical resection of vestibular schwannomas, radiosurgery has a lower morbidity rate, a similar risk of requiring further surgery, and higher patient satisfaction. As this information becomes more widely available to patients and third-party payors, radiosurgery may replace surgical resection as the preferred management strategy for patients with small to medium sized vestibular schwannomas in the United States. RATIONALE: It is estimated that 2500 patients are diagnosed with vestibular schwannomas each year in the United States. Assuming that 80% undergo surgery, 2000 operations are performed annually for newly diagnosed vestibular schwannomas. Data available since 1987 regarding the number of cases for which gamma knife radiosurgery was performed were used to predict the number of patients who will undergo vestibular schwannoma radiosurgery in the future. If the current trend continues, an equal number of patients will undergo surgical resection and radiosurgery to treat their vestibular schwannomas (∼1000/yr) sometime between 2005 and 2010. Moreover, it is predicted that by 2020, two-thirds of the patients who are newly diagnosed with vestibular schwannomas will undergo radiosurgery, with surgical resection being reserved for patients with large tumors associated with symptomatic brain stem compression. DISCUSSION: Early data regarding vestibular schwannoma radiosurgery predicted an exponential growth curve. Although it is premature to assume that the current trend will continue, it is likely that an ever increasing percentage of patients will undergo radiosurgery as accessibility to this alternative increases, and more data are published regarding long-term tumor growth control rates. If the mathematical model proves to be accurate, then stereotactic radiosurgery will replace surgical resection as the preferred management strategy for the majority of patients with vestibular schwannomas.

✓ A 22-year-old woman sustained a brachial plexus injury with supraganglionic rupture of the C-8 and T-1 nerve roots as a result of a traffic accident. She was operated on approximately 1 week following the accident. After a hemilaminectomy, the intradural defects in the ruptured roots were bridged with sural nerve grafts. Within 3 years she recovered function in all muscles supplied from the lower roots in the plexus except for the intrinsic hand muscles, but she had a persisting, complete sensory loss in the ulnar nerve distribution. The possibility for functional gain after repair of spinal root lesions in brachial plexus patients is discussed.

Materials and Methods: 40 SCLC patients treated with Gamma Knife from 2004 to 2011 were identified (15 males and 25 females with a median age of 61.3 years (range 36-79)). Thirty-seven patients had previous WBRT or prophylactic cranial irradiation. Three metastases (range 1-18) were treated per patient with 12Gy to 20Gy prescribed to the 45%-55% isodose line. Local and regional recurrence were identified using MRI. Local recurrence required pathologic evidence or MR SPECT changes consistent with tumor.

Presentation of the experiences with 254 acoustic neurinomas, treated at the Karolinska Gamma Knife Center from 1969 to 1991, with a minimum follow-up of 12 months.

Background The Leksell Gamma Knife® has been used for several decades as a relatively non-invasive, highly effective and precise therapeutic tool for brain disorders ranging from tumors to vascular malformations. It has a very benign side effect profile. To date many animal hydrocephalus models have been surgically or chemically invasive. Our exploratory model uses gamma knife to induce a lesion with the aim of increasing CSF outflow resistance at the cerebral aqueduct.

Purpose: The objective of this study was to analyze the relationships of dose and volume coverage in the comparison of a single shot (SS) and multiple shot (MS) Gammaknife treatments. The diseases studied were arteriovenous malformation (AVM), meningioma (MN), brainmetastasis (BM), pituitary tumor (PT), vestibular schwannoma (VS), and trigeminal neuralgia (TN) (n=10 for each disease). Method and Materials: The relationships between dose and volume coverage were measured at 90%, 80%, 70%, 60%, 50%, 40%, and 30% of the maximum doses using dose‐volume histograms (DVHs). We set the control volume covered by the prescribed dose (=50% of maximum dose) as unity. Then, volumes covered by different percentages of the maximum dose were divided by the control volume. This method was used for the analysis of four helmet sizes (4, 8, 14, 18 mm) and six diseases. The impact of plug patterns was analyzed for TN. Results: Average volume ratios (AVRs) covered by SS using four helmets were 0.31, 0.47, 0.61, 0.77, 1.36, and 2.06 times the control volume while AVRs covered by MS in the first five diseases were 0.03, 0.14, 0.34, 0.62, 1.47, and 2.23, at 90%, 80%, 70%, 60%, 40%, and 30% of the maximum dose, respectively. The mean doses for six diseases were 18.7, 15.1, 17.2, 15.0, 12.4 Gy to 50%, and 72 Gy to 80%, respectively. AVRs of MS to those of SS were 0.11, 0.30, 0.55, 0.81, 1.08 and 1.08, respectively. Plug patterns did not affect much on the relationship of dose and volume coverage in TN. Conclusions: Greater volumes were covered by the higher percentage isodose lines in SS than in MS. TN had the highest volume ratios covered by doses greater than 50% of the maximum dose; and PT and VS had higher volume ratios than AVM, MN, and BM in this study.

Results: The overall median survival was 7, 5 and 9 months for the GK, GK + WBRT and WBRT arms respectively. The local control was 87%, 91%. and 62% for GK, GK + WBRT and WBRT alone arms respectively, suggesting that the two radiosurgery arms were superior. However. the occurrence of new brain lesions was lower (43%, 19% and 23% for GK, GK + WBRT and WBRT alone respectively) in the two arms receiving WBRT. Regardless of treatment group, the local control and survival for patients who had surgical resection of brain metastases was 88% and 9 months compared to 73% and 6 months for those without resection suggesting some benefit of surgery. This survival benefit for surgery was not seen in patients who received GK as part of their treatment. Survival of patients by primary site was 6, 9.5 and 7 months for NSCLC. breast and colorectal cancers respectively. Patients with resected primary tumors had a median survival of 9 months compared with 5.5 months for those whose primary tumors were treated with radiation i- chemotherapy respectively. Conclusions: Local control of treated metastatic lesions is superior with the radiosurgery arms. However, the risk of developing new brain lesions is higher for patients not receiving whole brain radiotherapy. There was no difference in overall survival between the three arms. Resection of metastatic lesions did add to overall survival, but not for those receiving radiosurgery. Patients with breast and colorectal cancer faired better than those with lung cancer. Survival was better for patients with resected primary tumors compared to those treated with radiation i- chemotherapy.