Ravish V. Patwardhan

Efficacy of Vagal Nerve Stimulation in Children with Medically Refractory Epilepsy

OBJECTIVEThe effects of vagal nerve stimulation (VNS) on seizure frequency and quality of life were analyzed retrospectively in children with medically refractory epilepsy. METHODSThirty-eight children aged 11 months to 16 years underwent implantation of vagal nerve stimulators. Age of seizure onset, duration of epilepsy, and seizure type and frequency were recorded preoperatively. Age at implantation, length of follow-up, seizure type and frequency, and change in quality of life (QOL) were recorded postoperatively. Changes in QOL were assigned a QOL score by the caretakers on a visual analog scale of −1 (much worse) to +1 (much improved). RESULTSThe median follow-up period was 12 months (range, 10–18 mo). Eleven (29%), 15 (39%), 5 (13%), and 7 (18%) children had greater than 90% reduction, 50 to 90% reduction, less than 50% reduction, and no reduction in seizure frequency, respectively. For all children, seizure reduction by seizure type was as follows: atonic (80%), absence (65%), complex partial (48%), and generalized tonicoclonic (45%). The mean change in QOL score was 0.61. Eighty-six percent of the children had QOL scores of 0.5 (improved) or higher. Follow-up of at least 6 months was associated with greater seizure reduction (P = 0.05) and higher QOL score (P < 0.01). Seizure reduction was greater in children with onset of epilepsy after 1 year of age (P < 0.05). The age of the child and duration of epilepsy were not associated with greater or lesser degrees of seizure reduction. CONCLUSIONVNS provided improvements in seizure control for the majority of children regardless of age. QOL was improved in the majority of children with VNS. VNS should be considered for children with medically refractory epilepsy who have no surgically resectable focus.

Treatment of Dissecting Pseudoaneurysm of the Cervical Internal Carotid Artery Using a Wall Stent and Detachable Coils: Case Report.

OBJECTIVE AND IMPORTANCE This case illustrates the use of an endovascular stent and coiling combination to treat a giant wide-necked pseudoaneurysm of the cervical internal carotid artery. CLINICAL PRESENTATION A 20-year-old male patient presented with a bilateral dissection of the cervical internal carotid artery and a right giant wide-necked pseudoaneurysm of the cervical segment of the internal carotid artery after a high-speed motor vehicle collision. INTERVENTION After failing conservative therapy, the patient was treated by endovascular placement of a Palmaz wall stent at the level of the pseudoaneurysm and filling of the pseudoaneurysm with multiple Guglielmi detachable coils. Obliteration of the pseudoaneurysm was achieved, and patency of the right internal carotid artery was maintained. CONCLUSION The patients neurological symptoms resolved completely after treatment, and he sustained no neurological complications during the 20-month follow-up period. This case illustrates the successful treatment of a wide-based giant pseudoaneurysm by using a combination of an endovascular stent and coil embolization.

Ninth Cranial Nerve Stimulation for Epilepsy Control

Objective: To determine the anatomical and surgical feasibility of placement of a stimulator around the nerve of Hering (HN; a branch of cranial nerve nine). We previously determined the success of HN stimulation in controlling epileptiform activity in a canine model study. The present study assessed the ability to extrapolate the ease of surgical dissection and surrounding anatomy to humans. Methods: Fifteen human cadavers (8 male, 7 female) were studied. The HN on each side was specifically evaluated in each specimen with respect to its presence, size, surgically accessible length below the mandibular angle, relationship to the internal carotid artery (ICA) and carotid bifurcation and relation to the common facial vein (CFV), thyroid cartilage (superior edge) and superior cervical ganglion (SCG). Results: All 15 cadavers exhibited specimens of HN bilaterally, with the nerve diameter ranging from 0.5 to 1.5 mm (mean 1.0 mm); in relation to the ICA, the HN coursed anteromedially in 60%, anteriorly in 33% and anterolaterally in 7% of cases, and appeared to distinctly emerge at the level of the carotid bifurcation in all specimens. The surgically accessible length below the mandibular angle ranged from 6 to 30 mm (mean 15 mm). Relative to the carotid bifurcation, the superior edge of the thyroid cartilage was –35 to 33 mm (mean –5.4 mm) above; the CFV, which was clearly identifiable in only two thirds of the specimens, was –10 to 15 mm (mean 3.0 mm) above; and the inferiormost portion of the SCG was 6–30 mm (mean 16.6 mm) above. Conclusion: This study indicates that the HN was clearly present and surgically accessible in all human specimens. Based on the present study and our previous canine study, HN stimulation could be an important therapy for medically intractable epilepsy.

Histological appearance of a chronically stimulated vagus nerve in a pediatric patient.

Histological analysis of chronically stimulated human vagus nerves is lacking in the literature. In this study, we describe the first microscopic findings in a chronically stimulated left vagus nerve from a pediatric patient. Our results show many histological changes in and around the stimulated nerve with severe demyelination. Further long-term clinical and postmortem examinations of chronically stimulated vagus nerves in both children and adults are needed to ascertain whether prolonged exposure to electrical current can cause clinical dysfunction of this nerve.

Discernment of adipose versus nervous tissue: a novel adjunct solution in lipomyelomeningocele surgery.

Objective: To determine a solution capable of discerning adipose versus nervous tissue, to aid in surgical separation of the adipose tissue which appears to be visually indistinguishable from nervous tissue in lipomyelomeningoceles (LMMs). Methods: The following solutes (in normal saline) were investigated, both at 25 and 37°C: beta-carotene, vitamin D, vitamin E, lecithin, hydrogen peroxide, lipase, protease, hyaluronidase, partially purified collagenase, purified collagenase, trypsin, trypsin plus purified collagenase and non-solute-containing saline (control). Each solution was applied to a pediatric lipoma to determine gross effects over a period of approximately 30 min. If a solution appeared to affect the adipose tissue grossly, studies of functional in vivo sensory evoked and spontaneous potentials using that particular solution were conducted upon sheep spinal cord, nerve roots, dura and peripheral nerve. Additionally, histological studies were conducted to determine the effect of that solution upon adipose tissue, spinal cord, myelin, dura and nerve roots. Results: Of all solutions investigated, partially purified collagenase type 1 (T1C; Lot M0M4322, Code CLS-1, Worthington Biochemical Corporation, Lakewood, N.J., USA) at 37°C was the most successful in grossly altering the consistency and appearance of adipose tissue. This change was more apparent over 20–30 min following application of the solution to the adipose tissue. Solutions not containing T1C did not show appreciable results; purified collagenase plus trypsin did not appear comparable or superior to T1C. No significant histological or functional change was noted when comparing the spinal cord, nerve rootlets, myelin, dura or peripheral nerve from the T1C-treated group versus normal (untreated) control groups. Conclusion: T1C appears to be a potentially effective solution for application during LMM surgery in the acute setting, and such use of an adjunct solution may significantly aid in the safe surgical resection of LMMs. Pending further research, this technique may be applied for other indications which require discernment or alteration of adipose versus nervous tissue.

136 – Venous Angiomas

Publisher Summary This chapter focuses on the venous angiomas. Cerebral venous malformations are congenital vascular anomalies that may be located throughout the brain. The lesion consists of a radial array of medullary veins that converge into an enlarged transcerebral draining venous trunk. The venous trunk may continue to the cortical surface and drain into a dural sinus, or may connect with the deep venous system. Venous angiomas have been associated with intracerebral hemorrhage, focal neurological deficits, seizures, and headaches. They have also frequently been found as purely incidental lesions in patients with other intracranial pathology. In the vast majority of cases, venous angiomas should be treated conservatively. Associated headaches or seizures can almost always be controlled medically. In the rare reported cases in which a venous angioma has been resected for the treatment of chronic intractable headaches, there has been little symptomatic relief. If a large hemorrhage has occurred in association with a venous angioma, surgical evacuation of the clot may be necessary for decompression.