Hwa-shain Yeh

Indications for endovascular therapy for refractory vasospasm after aneurysmal subarachnoid hemorrhage: Experience at the University of Cincinnati

BACKGROUND Transluminal balloon angioplasty (TBA) and intra-arterial papaverine (IAP) appear to be valuable alternatives for the treatment of aneurysmal subarachnoid hemorrhage (SAH)-induced vasospasm refractory to maximal medical therapy. Although widely used, guiding principles for the implementation of TBA and IAP are not yet established. Based on our retrospective analysis, we define guidelines for endovascular therapy for refractory vasospasm based on our clinical results, adverse effects, and pattern of vasospasm. METHODS Medical records of 62 patients who experienced aneurysmal SAH-induced vasospasm refractory to hypervolemic, hypertensive, hyperdynamic therapy, and who were treated with IAP or TBA were reviewed. Fifty patients met the inclusion criteria for analysis. After careful scrutiny, two types of responses to endovascular treatment were identified. On the basis of that grouping, patients were divided into two groups according to the number of arterial segments involved, that is, monoterritorial and multiterritorial vasospasm. Multiple variables were analyzed. RESULTS Patients undergoing multiple endovascular procedures exhibited the worst outcomes. Patients in the monoterritorial group experienced a higher incidence of clinical improvement and better outcomes after endovascular treatment. Elevated intracranial pressure (ICP) and ICP-related deaths were more prominent in the multiterritorial group of patients. Sustained ICP elevation after administration of IAP was strongly associated with poor outcome in the multiterritorial group. CONCLUSIONS IAP is indicated as an early potential single-dose infusion in distal monoterritorial vasospasm, if angioplasty is impossible or unsafe. The use of IAP in bilateral diffuse vasospasm is discouraged because of the high susceptibility of these patients to develop elevated ICP. Multiple IAP infusions seem to have no significant impact on patient outcome. Balloon angioplasty seems to be indicated at an early juncture in patients with multiterritorial proximal vasospasm.

The effect of seizures on working memory and executive functioning performance

The aim of this study was to assess whether duration of seizure disorder and lifetime seizure load are associated with deficits in higher cognitive functions in patients with temporal lobe epilepsy (TLE) (N=207) or psychogenic nonepileptic seizures (PNES) (N=216). Multivariate regression analyses revealed that age at onset, duration, and group assignment were significant predictors of neuropsychological performance (all P<or=0.02), with group having a moderating relationship. Univariate analyses revealed different patterns of predictor effects on cognitive functioning within each diagnostic group. An impairment index was calculated for each individual, and univariate analyses revealed that age at TLE but not PNES onset was the only significant predictor of impairment (b=-0.005, P<0.001). The results suggest that earlier age at seizure onset, longer duration, and higher lifetime seizure frequency affect cognitive functioning in both the TLE and PNES groups, but differently within each group. These results have implications for early diagnosis and intervention in both groups.

Pericyte degeneration and thickening of basement membranes of cerebral microvessels in complex partial seizures: electron microscopic study of surgically removed tissue.

Complex partial seizures are associated with alterations in regional cerebral blood flow in abnormally spiking foci, as shown by positron emission tomography and single photon emission computed tomography, with an increase in flow ictally and a decrease interictally. Alterations of vasoregulation during ictal periods have also been described in animal seizure models. An electron microscopic study on human brain tissue from seven patients undergoing resections for the treatment of intractable complex partial seizures was performed to examine ultrastructural changes of the microvasculature and their locations within the microvessel wall. Biopsies were obtained intraoperatively from temporal lobe regions with electrocorticographically detected abnormal spiking and from regions without abnormality on electrocorticograms (control samples) removed as part of the therapeutic resection. A total of 539 microvessels from three regions were evaluated: spiking mesial temporal lobe, spiking lateral temporal cortex, and nonspiking (control) cortex. Evidence of pericyte degeneration (aggregates of cellular debris within the basement membrane) was noted in the majority of spiking area microvessels (76.7% in spiking mesial temporal cortex; 69.8% in spiking lateral temporal cortex) as compared with 37.8% of control microvessels (P less than 0.0005). Morphometric studies revealed a significant increase in total wall thickness, pericyte-basement membrane unit thickness, pericyte cytoplasmic density, basement membrane density, and basement membrane thickness in microvessels from spiking (mesial and lateral temporal cortex), as compared to control areas (P less than 0.01). No statistically significant difference was noted in pericyte coverage or pericyte or endothelial mitochondrial densities between microvessels in spiking and control regions. This study shows degeneration of pericytes, cells thought to play an essential role in microvascular hemodynamics, and thickening of microvessel walls in abnormally spiking brain regions in patients with intractable complex partial seizures. The pericyte degeneration and basement membrane thickening in abnormally spiking areas may explain alterations in vasoregulation, by a decrease in the microvascular compliance and in cross-capillary diffusion.

Microsurgical treatment of intractable hemifacial spasm.

Ten patients with intractable hemifacial spasm were treated by posterior fossa exploration and microsurgical technique. These patients have been followed 1 to 5 years. The spasmodic motor disorder was related to compression of the 7th nerve or its exit zone at the brain stem by a dolichoectatic anterior inferior cerebellar artery in eight patients and to kinking and ectasia of the basilar or vertebral artery in two patients. In five patients, there were prominent arachnoidal adhesions in the cerebellopontine angle, and an arachnoid cyst was a component of the lesion in another patient. Additional conditions associated with hemifacial spasm included geniculate neuralgia, facial paresis, vertigo, hearing loss, and trigeminal neuralgia. The surgical morbidity and postoperative results are discussed.

Seizure control and extent of mesial temporal resection

SummaryControversy exists about the extent of mesial temporal lobe resection that improves seizure control in patients with temporal lobe epilepsy.In this retrospective study, 70 patients with mesial temporal seizure activity (without evidence of tumor or vascular malformation) were surgically treated and followed for at least 2 years. The extent of mesial temporal resection was based on the findings of interictal and ictal discharges using depth electrodes, which were inserted preoperatively or intraoperatively by the orthogonal approach to the amygdaloid and hippocampal regions. Only the amygdala was resected along with the limited lateral neocortex if no epileptiform activity involved the hippocampus. The amount of hippocampal excision was determined by the extent of interictal seizure activity.The following groups became seizure free: all 8 patients with only amygdalar resection; 6 of 10 patients with amygdalar and ⩽ 1cm hippocampal resection; 23 of 38 with 1–2 cm hippocampal removal, and 11 of 14 with > 2cm hippocampal excision. In cases where there was no hippocampal resection, neuropsychological outcome compared favorably with controls.Our results suggest that although most patients with temporal lobe epilepsy require hippocampal resection of varying degrees, there is a subset in whom the amygdala may be the crucial element of a mesial temporal epileptogenic network. These patients can undergo a surgical resection sparing the hippocampus without compromising seizure outcome.

Intratemporal Schwannoma of the Facial Nerve

Two patients with schwannomas that originated from the region of the geniculate ganglion of the facial nerve are reported. They presented with progressive facial nerve paralysis and variable disturbance of hearing. Computed tomograms demonstrated a mass lesion eroding the temporal bone (petrous portion) and extending into the middle fossa. The treatment consisted of complete excision of the tumor, and a hypoglossal-facial nerve anastomosis. Computed tomography should be performed on all patients with facial palsy of a progressive nature. Early diagnosis and surgical treatment of facial schwannoma should permit preservation of function of the facial and the acoustic nerves.

Tic convulsif, the combination of geniculate neuralgia and hemifacial spasm relieved by vascular decompression

A patient had combined otalgia and intractable unilateral facial spasm, relieved by microsurgical vascular decompression of the seventh and eighth cranial nerve complex in the cerebellopontine angle without section of the intermediate nerve. A dolicho-ectatic anterior inferior cerebellar artery compressed the seventh and eighth cranial nerves complex, suggesting that vascular compression of the intermediate nerve or of the sensory portion of the facial nerve may cause geniculate neuralgia. “Tic convulsif” seems to be a combination of geniculate neuralgia and hemifacial spasm. This combination could be due to vascular compression of the sensory and motor components of the facial nerve at their junction with the brainstem.

Anterior interhemispheric approach to aneurysms of the anterior communicating artery

A modified anterior interhemispheric approach for clipping aneurysms of the anterior communicating artery is described. This approach is preferred on anatomical grounds because the anterior circle of Willis can be fully visualized with minimal manipulation of the frontal lobes and anterior cerebral arteries. The advantages of this approach are minimal traction, reduced operative time, and preservation of the olfactory nerve.

What Does the Family Pictures Subtest of the Wechsler Memory Scale-III Measure? Insight Gained from Patients Evaluated for Epilepsy Surgery

The Family Pictures (FP) task is a new subtest of the Wechsler Memory Scale Version III (WMS-III) used to assess visual memory and learning. This study assessed the extent to which different cognitive abilities contribute to performance on the FP task in 125 patients evaluated for epilepsy surgery. Results indicated that the FP task relies heavily on auditory-verbal based cognitive abilities, as well as visual memory, and may better represent a general measure of memory performance. These results raise questions about the appropriateness of including FP task performance in the calculations of the WMS-III Visual Index scores.

Morbidity and mortality of carotid endarterectomy under local anesthesia: a retrospective study

It has been shown that carotid endarterectomy reduces the incidence of stroke in patients with symptomatic extracranial occlusive vascular disease in the absence of major perioperative complications such as stroke or death. We present a retrospective study of 106 carotid endarterectomies performed under local anesthesia in 100 patients in whom transient ischemic attack (TIA) or minor stroke had occurred. Nonfatal stroke occurred in 2%, and TIA occurred in 1%. There was no perioperative mortality. Our study suggests that, under local anesthesia, even high risk patients can be operated safely and the majority of carotid endarterectomies can be performed without the use of an indwelling shunt. Meticulous surgical technique is of great importance for achieving low perioperative complications.