Prospective Evaluation of the Time Course of White Matter Edema Associated with Implanted Deep Brain Stimulation Electrodes.

INTRODUCTION: Deep brain stimulation (DBS) is commonly used in the treatment of medically refractory movement disorders. There have been several reports in the literature of edema developing around the implanted electrode. Most of these studies have been retrospective, suggesting that the time course and incidence of this edema are underestimated. An understanding of the incidence and time course of edema related to DBS leads is important to allow clinicians to better assess the correct course of action when edema following DBS implantation is observed. METHODS: We examined both the time course and prevalence of edema following DBS implantation by obtaining a series of postoperative MRI scans from patients who underwent DBS surgery. Edema volume was quantified by a single neuroradiologist, measuring the peri-electrode T2 signal change. RESULTS: We examined postoperative MRIs in thirteen patients with fifteen DBS electrode implants. Eleven patients exhibited white matter edema on at least 1 postoperative MRI, with none being symptomatic. Edema was completely resolved in 4 of the electrode implants through postoperative day 70, with the remaining cases still exhibiting edema at the last imaged time point. DISCUSSION/CONCLUSION: In this study, we obtained a regimented series of postoperative MRIs in an effort to determine the time course and incidence of edema. Our results show that edema following DBS implant is not rare, is often asymptomatic, and may resolve over many weeks.

Feasibility of Proton Beam Therapy for Ocular Melanoma Using a Novel 3D Treatment Planning Technique.

PURPOSE: We evaluated sparing of normal structures using 3-dimensional (3D) treatment planning for proton therapy of ocular melanomas. METHODS AND MATERIALS: We evaluated 26 consecutive patients with choroidal melanomas on a prospective registry. Ophthalmologic work-up included fundoscopic photographs, fluorescein angiography, ultrasonographic evaluation of tumor dimensions, and magnetic resonance imaging of orbits. Three tantalum clips were placed as fiducial markers to confirm eye position for treatment. Macula, fovea, optic disc, optic nerve, ciliary body, lacrimal gland, lens, and gross tumor volume were contoured on treatment planning compute tomography scans. 3D treatment planning was performed using noncoplanar field arrangements. Patients were typically treated with 3 fields, with at least 95% of planning target volume receiving 50 GyRBE in 5 fractions. RESULTS: Tumor stage was T1a in 10 patients, T2a in 10 patients, T2b in 1 patient, T3a in 2 patients, T3b in 1 patient, and T4a in 2 patients. Acute toxicity was mild. All patients completed treatment as planned. Mean optic nerve dose was 10.1 Gy relative biological effectiveness (RBE). Ciliary body doses were higher for nasal (mean: 11.4 GyRBE) than temporal tumors (5.8 GyRBE). Median follow-up was 31 months (range: 18-40 months). Six patients developed changes which required intraocular bevacizumab or corticosteroid therapy, but only 1 patient developed neovascular glaucoma. Five patients have since died: 1 from metastatic disease and 4 from other causes. Two patients have since required enucleation: 1 due to tumor and 1 due to neovascular glaucoma. CONCLUSIONS: 3D treatment planning can be used to obtain appropriate coverage of choroidal melanomas. This technique is feasible with relatively low doses to anterior structures, and appears to have acceptable rates of local control with low risk of enucleation. Further evaluation and follow-up is needed to determine optimal dose-volume relationships for organs at risk to decrease complications rates.

Obstructive hydrocephalus from venous sinus thrombosis.

BACKGROUND: Cerebral venous sinus thrombosis (CVST) is a rare form of stroke. Although increased intracranial pressure is a well-described complication of CVST, hydrocephalus has rarely been reported. CASE: We present the case of a 49-year-old woman who presented with one week of headache, vomiting, and progressive neurologic deterioration leading to coma. Head CT and MRI identified extensive CVST and accompanying hydrocephalus. She was treated with systemic anticoagulation as well as mechanical and pharmacologic endovascular thrombolysis. An external ventricular drain (EVD) was not inserted given the potential bleeding risk while anticoagulated. Subsequently, she made an excellent recovery and had a normal neurologic exam at long-term follow up. CONCLUSION: Hydrocephalus is a rare complication of cerebral venous sinus thrombosis. Treatment of hydrocephalus with an EVD may not be necessary if interventions are undertaken to urgently recanalize thrombosed venous sinuses.