Leonardo Frighetto

Increased Fast ripple to ripple Ratios Correlate with Reduced Hippocampal Volumes and Neuron Loss in Temporal Lobe Epilepsy Patients

Purpose: To determine whether hippocampal sclerosis might form an anatomical substrate for pathological high‐frequency oscillations in patients with temporal lobe epilepsy (TLE).

Linear accelerator radiosurgery using 90 gray for essential trigeminal neuralgia: Results and dose volume histogram analysis

OBJECTIVETo evaluate treatment of essential trigeminal neuralgia with 90 Gy delivered by a linear accelerator dedicated to radiosurgery. METHODSThis is a retrospective case series of 25 patients with essential trigeminal neuralgia treated from March 1999 to March 2001. All were treated with 90 Gy by means of a 5-mm collimator directed to the nerve root entry zone. Patient follow-up (range, 8–52 mo; median, 18 mo) was completed by an uninvolved party. Dose volume histograms of the brainstem were developed for the 20, 30, and 50% isodose lines by means of radiosurgery planning software. RESULTSAll patients obtained good to excellent pain relief with treatment. Nineteen (76%) of 25 patients achieved excellent pain relief (pain-free without medication). Six patients (24%) achieved good pain relief (50–90% reduction of pain with or without medication). Median time to pain relief was 2 months. Eight patients (32%) experienced relapse 4 to 13 months after treatment. Eight patients (32%) developed facial numbness, but none developed painful numbness. Mean brainstem volume within the 50% isodose line and occurrence of numbness was statistically significant (P = 0.03). There was no correlation between brainstem volume treated and outcome. CONCLUSIONDedicated linear accelerator-based stereotactic radiosurgery that uses a 5-mm collimator to deliver 90 Gy to the nerve root entry zone is a safe and effective method for the treatment of essential trigeminal neuralgia. Care should be taken to limit brainstem volume included in the 50% isodose line in the treatment plan to avoid facial numbness.

Modulation of food intake following deep brain stimulation of the ventromedial hypothalamus in the vervet monkey: Laboratory investigation

OBJECT Deep brain stimulation (DBS) has become an effective therapy for an increasing number of brain disorders. Recently demonstrated DBS of the posterior hypothalamus as a safe treatment for chronic intractable cluster headaches has drawn attention to this target, which is involved in the regulation of diverse autonomic functions and feeding behavior through complex integrative mechanisms. In this study, the authors assessed the feasibility of ventromedial hypothalamus (VMH) DBS in freely moving vervet monkeys to modulate food intake as a model for the potential treatment of eating disorders. METHODS Deep brain stimulation electrodes were bilaterally implanted into the VMH of 2 adult male vervet monkeys by using the stereotactic techniques utilized in DBS in humans. Stimulators were implanted subcutaneously on the upper back, allowing ready access to program stimulation parameters while the animal remained conscious and freely moving. In anesthetized animals, intraoperatively and 6-10 weeks postsurgery, VMH DBS parameters were selected according to minimal cardiovascular and autonomic nervous system responses. Thereafter, conscious animals were subjected to 2 cycles of VMH DBS for periods of 8 and 3 days, and food intake and behavior were monitored. Animals were then killed for histological verification of probe placement. RESULTS During VMH DBS, total food consumption increased. The 3-month bilateral implant of electrodes and subsequent periods of high-frequency VMH stimulation did not result in significant adverse behavioral effects. CONCLUSIONS This is the first study in which techniques of hypothalamic DBS in humans have been applied in freely moving nonhuman primates. Future studies can now be conducted to determine whether VMH DBS can change hypothalamic responsivity to endocrine signals associated with adiposity for long-term modulation of food intake.

Prospective Study of Stereotactic Radiosurgery Without Whole Brain Radiotherapy in Patients with Four or Less Brain Metastases: Incidence of Intracranial Progression and Salvage Radiotherapy

This prospective study was conducted to evaluate the treatment outcome after stereotactic radiosurgery (SRS) alone with special attention to its influence on intracranial freedom from progression (FFP), local control, time to whole brain radiotherapy (WBRT), and survival. Forty-one patients with brain metastases who met the inclusion criteria were enrolled in this prospective cohort and treated by SRS alone between January 1998 and September 2001. The overall local control rate was 76%. The one year actuarial intracranial FFP was 33%. Ten patients (24%) had relapse at treated site. Twenty-three patients (56%) had intracranial progression with a median time of 4.25 months (1–24.6). Salvage radiotherapy was given in 21 patients (51%). Only 12 (29%) patients required WBRT with the median time to WBRT after SRS of 4.85 months. Nine patients (22%) underwent additional SRS at the median time of 5 months after the first procedure. The median survival was 10 months. At the time of follow up, 16 patients (39%) were still alive with a range of 6–31 months. This prospective study suggests that the omission of WBRT in the initial treatment of patients with SRS for four or less brain metastases may allow up to 70% of patients to avoid WBRT.

Noninvasive linear accelerator radiosurgery as the primary treatment for trigeminal neuralgia

The application of a dedicated linear accelerator (DLINAC) as a noninvasive surgical treatment for trigeminal neuralgia has not yet been demonstrated. This work evaluates the outcome and indications of 22 patients submitted to DLINAC radiosurgery as a primary treatment for essential trigeminal neuralgia. At last follow-up evaluation, 21 patients (95.5%) had sustained significant pain relief. DLINAC radiosurgery is safe and effective as a primary noninvasive surgical treatment for selected patients with essential trigeminal neuralgia.

Radiosurgery and stereotactic radiation therapy of skull base meningiomas: proposal of a grading system.

Objective: The development of a grading system to guide treatment selection, and predict treatment difficulty and outcome of skull base meningiomas infiltrating the cavernous sinus which are managed by stereotactic radiosurgery (SRS) and stereotactic radiotherapy (SRT), based on an 8-year experience with stereotactic radiation of skull base meningiomas. Methods: T1 gadoliniun-enhanced magnetic resonance imaging (MRI) of 40 patients with skull base meningiomas, with or without prior surgery, who underwent radiosurgery or stereotactic radiation therapy from 1991 to 1998 at the UCLA Medical Center were reviewed, and the result of treatment was related to the tumor grade. Grade was based on tumor infiltration of the cavernous sinus and extension into adjacent structures. Treatment was performed with a linac-based system. The dose prescribed to the periphery of the tumor for SRS patients (n = 34) ranged from 12 to 22 Gy, and the maximum dose delivered to the tumor ranged from 24 to 46 Gy. SRT (n = 6). Treatment was planned using a single isocenter, usually prescribed to the 90% isodose volume, bringing the fractionation scheme to the maximal tolerance of the optic apparatus. The periphery dose ranged from 24 to 46 Gy with a maximum dose of 45 to 51 Gy. Clinical and MRI follow-up was performed every six months for the first 3 years and every year thereafter. Results: Grade I meningiomas were restricted to the cavernous sinus (n = 12). Grade II cavernous sinus meningiomas extended to the clivus and/or the petrous bone, without compression of the brainstem (n = 9). Grade III meningiomas had superior and/or anterior extension with compression of the optic nerve or tract (n = 9). Grade IV tumors compressed the brain stem (n = 8), and Grade V were bilateral lesions (n = 2). Tumor control rates were 90% for Grade I, 86% for Grade II, 86% for Grade III, 42% for Grade IV and no control for tumors Grade V. Complications were not related to tumor grade. Conclusion: This grading system correlated with outcome and difficulty in planning radiosurgery. Failure of treatment was more likely to occur in patients with higher Grade tumors.

Preliminary Novalis Experience in the Treatment of Skull Base Chordomas with StereotacticRadiosurgery and Stereotactic Radiotherapy

Purpose: The treatment of chordomas is challenging. The role of radiation therapy in addition to surgery is well established. Different techniques have been applied aiming to improve tumor local contr

Long-Term Follow-Up Using Linac Radiosurgery and Stereotactic Radiotherapy as a Minimally Invasive Treatment for Intracranial Meningiomas

Purpose: Report of technical aspects, results and strategies of stereotactic radiosurgery (SRS) and stereotactic radiation therapy (SRT) for treatment of intracranial meningiomas. Methods: A retrospective review of intracranial meningiomas treated at UCLA from May 1991 to July 2003 was performed with emphasis on technical aspects, radiological and clinical results. 161 patients with intracranial meningiomas treated by linear accelerator (Linac) stereotactic radiation were identified. There were 33 meningiomas in 32 patients with follow-up more than 48 months. Mean patient age was 57.2 years (range 19–87). There were 25 females and 7 males. 21 patients had surgical resection prior to radiosurgery. Stereotactic radiation was the primary treatment in 12 patients. Single dose radiation to 26 lesions and 7 were treated with fractionated technique. SRS dose prescribed to the periphery of the tumor ranged from 12 to 22 Gy (mean 15 Gy), SRT dose ranged from 23 to 54 Gy (mean 48 Gy). The prescription isodose ranged from 50 to 90% for the single dose group and from 85 to 90% for the fractionated treatments. Results: Follow-up was available for 32 patients treated between 48 and 125 months (mean 72.5). Tumor growth control was achieved in 30 benign meningiomas treated with SRS (92.3%) and in 7 benign meningiomas treated with SRT (100%). Worsening of previous neurological deficit was identified in 2 patients (7.9%) treated with SRS. No complications were found in SRT patients. Conclusion: Radiosurgery has been an alternative to surgical resection of selected intracranial meningiomas. Patients with tumors not amenable to either surgery or radiosurgery are now candidates for a less invasive technique than conventional radiotherapy. The need for total/subtotal surgical resection of these tumors is being challenged by superior imaging capabilities that allow for precise and effective stereotactic radiotherapy.