Efstathios Papavassiliou

Thalamic Deep Brain Stimulation for Essential Tremor: Relation of Lead Location to Outcome

OBJECTIVE:Thalamic deep brain stimulation (DBS) is commonly used to treat essential tremor, but the optimal lead location within the thalamus has not been systematically evaluated. We examined the relation of lead location to clinical outcome in a series of essential tremor patients treated by thalamic DBS. METHODS:Fifty-seven leads in 37 patients were studied. Lead locations were measured by postoperative magnetic resonance imaging. Contralateral arm tremor was assessed in the DBS-on and DBS-off states using the Fahn-Tolosa-Marin tremor rating scale, with a mean follow-up of 26 months. Lead locations were statistically correlated, using analysis of variance, with percent improvement in tremor resulting from DBS activation. RESULTS:Improvement in tremor score was significantly correlated with lead location in both the anteroposterior and lateral dimensions. In the plane of the commissures, the optimal electrode location was determined statistically to be 6.3 mm anterior to the posterior commissure and 12.3 mm lateral to the midline, or 10.0 mm lateral to the third ventricle. CONCLUSION:Optimal electrode location for thalamic DBS in essential tremor corresponds to the anterior margin of the ventralis intermedius nucleus. Leads located greater than 2 mm (in the plane of the commissures) from the optimal coordinates are more likely to be associated with poor tremor control than leads within 2 mm of the optimal location. The incidence of true physiological tolerance to the antitremor effect of thalamic DBS (defined as poor tremor control in spite of lead location within 2 mm of the optimal site) was found to be 9%.

Loss of benefit in VIM thalamic deep brain stimulation (DBS) for essential tremor (ET): how prevalent is it?

Ventralis intermedius (Vim) thalamic deep brain stimulation for medication-refractory essential tremor (ET) has been shown to significantly improve severity of limb tremor in several large case series with significant reduction in objective motor scores. A variable proportion of patients experience decline in benefit over time, however, most studies have not been designed to describe the phenomenon of waning benefit in terms that are helpful for patient counseling. In this retrospective single center study, we define waning benefit as a phenomenon that occurs after patients begin to require reprogramming visits to optimize DBS benefit on tremor. We employed a survival analysis with time to escape (TTE) as a quantitative measure of time elapsed between implantation and the need for subsequent reprogramming. In our cohort of ET patients operated on with Vim DBS from 1994 to 2009, among 45 subjects who met inclusion criteria, 73% reported waning benefit at some point during a mean follow-up period of 56 months (range 12-152 months). The mean TTE from implantation date was 18 months (range 3-75 months). We conclude that loss of benefit over time from Vim DBS for ET is more prevalent than previously published estimates have indicated and should be discussed during patient counseling regarding durability of expected benefit. In addition, this data suggests that a disease-based explanation rather than technical factors are more likely to explain the decline in benefit.

Effect of Abdominal Insufflation for Laparoscopy on Intracranial Pressure

IMPORTANCE Increased abdominal pressure may have a negative effect on intracranial pressure (ICP). Human data on the effects of laparoscopy on ICP are lacking. We retrospectively reviewed laparoscopic operations for ventriculoperitoneal shunt placement to determine the effect of insufflation on ICP. OBSERVATIONS Nine patients underwent insufflation with carbon dioxide (CO(2)) at pressures ranging from 8 to 15 mm Hg and ICP measured through a ventricular catheter. We used a paired t test to compare ICP with insufflation and desufflation. Linear regression correlated insufflation pressure with ICP. The mean ICP increase with 15-mm Hg insufflation is 7.2 (95% CI, 5.4-9.1 [P < .001]) cm H(2)O. The increase in ICP correlated with increasing insufflation pressure (P = .04). Maximum ICP recorded was 25 cm H(2)O. CONCLUSIONS AND RELEVANCE Intracranial pressure significantly increases with abdominal insufflation and correlates with laparoscopic insufflation pressure. The maximum ICP measured was a potentially dangerous 25 cm H(2)O. Laparoscopy should be used cautiously in patients with a baseline elevated ICP or head trauma.

John Lykoudis: an unappreciated discoverer of the cause and treatment of peptic ulcer disease

discovery of Helicobacter pylori, and their seminal work has revolutionised our understanding of peptic ulcer disease. In an enormous effort spanning over 100 years, investigators have tried to unravel the causes of peptic ulcer disease. Nearly all concentrated on gastric acid. Only a few examined the possibility of an infectious cause. The “bacterial hypothesis” for the causes of peptic ulcer disease was articulated as early as 1875, and since then a small number of investigators has attempted to show a causative role of microorganisms observed in or around peptic ulcers. Some, including Kussmaul in 1868 and Gorham in 1940, advocated the use of bismuth compounds to treat ulcers. Benjamin Burg at Mount Sinai Hospital in New York used partial vagotomy to reduce secondary infections in ulcer margins. Burg’s ideas probably prompted Constance Guion in the neighbouring New York Hospital to prescribe the antibiotic chlortetracycline for peptic ulcer disease in 1946—a practice she later abandoned. These investigators worked in the shadow of the prevailing opinion that hydrochloric acid and the vagus nerve were at the centre of the pathogenesis of peptic ulcer disease. Moynihan best expressed the orthodox medical thinking when he ascribed duodenal ulcer to “the digestion of the duodenal mucosa by the hyperacid gastric juice”. We have come across the efforts of the late John Lykoudis, who in the 1950s concluded that peptic ulcer disease and gastritis had an infectious cause, and who devised an antibiotic treatment that he gave to thousands of patients. We present here a summary of his work as a contribution to the history of peptic ulcer disease. John Lykoudis (1910–80, figure) graduated from the Greek Military Medical School in 1934. In 1938, he started a medical practice in his native Missolonghi, the small town where the English poet Lord Byron fought for Greek independence and eventually died in 1824.

Upregulation of inflammatory gene transcripts in periosteum of chronic migraineurs: Implications for extracranial origin of headache

Chronic migraine (CM) is often associated with chronic tenderness of pericranial muscles. A distinct increase in muscle tenderness prior to onset of occipital headache that eventually progresses into a full‐blown migraine attack is common. This experience raises the possibility that some CM attacks originate outside the cranium. The objective of this study was to determine whether there are extracranial pathophysiologies in these headaches.

THALAMIC DEEP BRAIN STIMULATION FOR ESSENTIAL TREMOR

OBJECTIVE Thalamic deep brain stimulation (DBS) is commonly used to treat essential tremor, but the optimal lead location within the thalamus has not been systematically evaluated. We examined the relation of lead location to clinical outcome in a series of essential tremor patients treated by thalamic DBS. METHODS Fifty-seven leads in 37 patients were studied. Lead locations were measured by postoperative magnetic resonance imaging. Contralateral arm tremor was assessed in the DBS-on and DBS-off states using the Fahn-Tolosa-Marin tremor rating scale, with a mean follow-up of 26 months. Lead locations were statistically correlated, using analysis of variance, with percent improvement in tremor resulting from DBS activation. RESULTS Improvement in tremor score was significantly correlated with lead location in both the anteroposterior and lateral dimensions. In the plane of the commissures, the optimal electrode location was determined statistically to be 6.3 mm anterior to the posterior commissure and 12.3 mm lateral to the midline, or 10.0 mm lateral to the third ventricle. CONCLUSION Optimal electrode location for thalamic DBS in essential tremor corresponds to the anterior margin of the ventralis intermedius nucleus. Leads located greater than 2 mm (in the plane of the commissures) from the optimal coordinates are more likely to be associated with poor tremor control than leads within 2 mm of the optimal location. The incidence of true physiological tolerance to the antitremor effect of thalamic DBS (defined as poor tremor control in spite of lead location within 2 mm of the optimal site) was found to be 9%.

Complicated spontaneous intracranial hypotension treated with intrathecal saline infusion

Spontaneous intracranial hypotension typically results from a spontaneous cerebrospinal fluid (CSF) leak.1 ,2 Symptoms include orthostatic headache and meningism without a recent dural puncture,2 and may be associated with distant and trivial trauma.3 The diagnosis may be made clinically by the typical headache and supported by pachymeningeal enhancement on MR scan or a low CSF pressure at lumbar puncture.2 If severe and continued, the low pressure can have serious complications, including brain sagging with subdural hygromas,4 cerebral venous sinus thrombosis,5 subdural haematoma2 and subarachnoid haemorrhage.6 Indicators of a serious complication include cranial nerve palsy and worsening mental status, progressing to coma.4 Herniation can result from a pressure differential, with spinal intrathecal pressure lower than intracranial pressure. Left untreated, this can result in significant morbidity or death. Treatment may be conservative, involving strict bed rest, use of the Trendelenburg position, intravenous/oral hydration and caffeine. If these measures fail, an epidural blood patch, starting ‘blindly’ in the lumbar region, may help.7 People with persistent symptoms need imaging with a radionuclide scan or CT/MR myelography to help localise the CSF leak, followed by a targeted epidural blood patch or surgical repair.3 ,7 Intrathecal saline infusion has succeeded in treating otherwise refractory spontaneous intracranial hypotension.8–12 We report a case of spontaneous intracranial hypotension complicated by bilateral subdural hygromas and subdural haematomas, with uncal herniation, coma and bilateral posterior cerebral artery infarctions. We treated her with an intrathecal saline infusion under pressure monitoring, with rapid resolution of coma. A 57-year-old woman presented to another hospital with orthostatic headache, neck pain, nausea and vomiting. The previous day, she had coughed vigorously during a viral illness. She re-presented 1 week later with persistent symptoms; examination was normal, but a CT scan of the head …

Ventriculoperitoneal shunting: Laparoscopically assisted versus conventional open surgical approaches.

Objectives: Ventriculoperitoneal shunting (VPS) is a mainstay of hydrocephalus therapy, but carries a significant risk of device malfunctioning. This study aims to compare the outcomes of laparoscopic ventriculoperitoneal shunting versus open ventriculoperitoneal shunting (OVPS) VPS-placement and reviews our findings in the pertinent context of the literature from 1993 to 2012. Materials and Methods: Between 2003 and 2012, a total of 232 patients underwent first time VPS placement at Beth Israel Deaconess Medical Center. Of those, 155 were laparoscopically guided and 77 were done conventionally. We analyzed independent variables (age, gender, medical history, clinical presentation, indication for surgery and surgical technique) and dependent variables (operative time, post-operative complications, length of stay in the hospital) and occurrence of shunt failure. Results: Mean operative time was 43.7 min (18.0-102.0) in the laparoscopic group versus 63.0 min (30.0-151.0) in the open group, (P < 0.05). Length of stay was similar, 5 days in the laparoscopic and in the open group, (P = 0.945). The incidence of shunt failure during the entire follow-up period was not statistically different between the two groups, occurring in 14.1% in the laparoscopic group and 16.9% in the open group, (P = 0.601). Kaplan-Meier analysis demonstrated no difference in shunt survival between the two groups (P = 0.868), with functionality in 85% at 6-months and 78.5% at 1-year. Conclusion: According to our study, LVPS-placement results compare similarly to OVPS placement in most aspects. Since laparoscopic placement is not routinely indicated, we suggest a prospective study to assess its value as an alternate technique especially suitable in obese patients and patients with previous abdominal operations.

End of day dyskinesia in advanced Parkinson's disease can be eliminated by bilateral subthalamic nucleus or globus pallidus deep brain stimulation

We report the therapeutic effects of deep brain stimulation (DBS) in 2 patients with Parkinsons disease (PD) with severe end of dose dyskinesia that was resistant to medical therapy. In both patients, severe, end of day ballistic dyskinesias occurred when the last levodopa dose of the day was wearing off. Globus pallidus (GPi) DBS in 1 case and subthalamic (STN) DBS in the second case produced full resolution of end of day dyskinesia.

Utilizing Fast Spin Echo MRI to Reduce Image Artifacts and Improve Implant/Tissue Interface Detection in Refractory Parkinson’s Patients with Deep Brain Stimulators

Introduction. In medically refractory Parkinsons disease (PD) deep-brain stimulation (DBS) is an effective therapeutic tool. Postimplantation MRI is important in assessing tissue damage and DBS lead placement accuracy. We wanted to identify which MRI sequence can detect DBS leads with smallest artifactual signal void, allowing better tissue/electrode edge conspicuity. Methods. Using an IRB approved protocol 8 advanced PD patients were imaged within MR conditional safety guidelines at low RF power (SAR ≤ 0.1 W/kg) in coronal plane at 1.5T by various sequences. The image slices were subjectively evaluated for diagnostic quality and the lead contact diameters were compared to identify a sequence least affected by metallic leads. Results and Discussion. Spin echo and fast spin echo based low SAR sequences provided acceptable image quality with comparable image blooming (enlargement) of stimulator leads. The mean lead diameters were 2.2 ± 0.1 mm for 2D, 2.1 ± 0.1 mm for 3D, and 4.0 ± 0.2 mm for 3D MPRAGE sequence. Conclusion. Low RF power spin echo and fast spin echo based 2D and 3D FSE sequences provide acceptable image quality adjacent to DBS leads. The smallest artifactual blooming of stimulator leads is present on 3D FSE while the largest signal void appears in the 3D MPRAGE sequence.