No abstract

Thirty-five consecutive adults with Chiari malformation and progressive symptoms underwent surgical treatment at a single institution over a 3-year period. All patients underwent magnetic resonance imaging scan before and after surgery. Images of the craniovertebral junction confirmed tonsillar herniation in all cases and allowed the definition of two anatomically distinct categories of the Chiari malformation in this age group. Twenty of the 35 patients had concomitant syringomyelia and were classified as Type A. The remaining 15 patients had evidence of frank herniation of the brain stem below the foramen magnum without evidence of syringomyelia and were labeled Type B. Type A patients had a predominant central cord symptomatology: Type B patients exhibited signs and symptoms of brain stem or cerebellar compression. The principal surgical procedure consisted of decompression of the foramen magnum, opening of the fourth ventricular outlet, and plugging of the obex. Significant improvement in preoperative symptoms and signs was observed in 9 of the 20 patients (45%) with syringomyelia (Type A), as compared to 13 of the 15 patients (87%) without syringomyelia (Type B). Postoperative reduction in syrinx volume was observed in 11 of the 20 patients with syringomyelia, including all 9 patients with excellent results. Magnetic resonance imaging has allowed a classification of the adult Chiari malformation in adults based on objective anatomic criteria, with clinical and prognostic relevance. The presence of syringomyelia implies a less favorable response to surgical intervention.

Background and Purpose-The pathogenesis of intracranial aneurysms (IAs) remains elusive. Most studies have focused on individual genes, or a few interrelated genes or products, at a time in human IA. However, a broad view of pathologic mechanisms has not been investigated by identifying pathogenic genes and their interaction in networks. Our study aimed to analyze global gene expression patterns in the IA wall. Methods-To our knowledge, our group was the first to perform Illumina microarray analysis on human IA via comparison of aneurysm wall and superficial temporal artery tissues from 6 consecutive patients. We adopted stringent statistical criteria to the individual genes; genes with a false discovery rate Ͻ0.01 and Ͼ2-fold change were selected as differentially expressed. To identify the overrepresented biologic pathways with the differentially expressed genes, we performed hypergeometric testing of the genes selected by relaxed criteria of PϽ0.01 and fold change Ͼ1.5. Results-There are 326 distinct differentially expressed genes between IA and superficial temporal artery tissues (Ͼ2-fold change) with a false discovery rate Ͻ0.01. Analysis of the Kyoto Encyclopedia of Genes and Genomes pathways revealed the most impacted functional pathways: focal adhesion, extracellular matrix receptor interaction, and cell communication. Analysis of the Gene Ontology also supported the involvement of another 2 potentially important pathways: inflammatory response and apoptosis. Conclusions-The differentially expressed genes in the aneurysm wall may shed light on aneurysm pathobiology and provide novel targets for therapeutic intervention. These data will help generate hypotheses for future studies. (Stroke.

We present our surgical experience with second operations in 15 patients with recurrent intractable partial seizures after resection for epilepsy. The interval from the first operation until the first recurrence of seizures ranged from 1 day to 7 months (mean, 62 days);. The interval between the first and second operations ranged from 3 months to 12 years (mean, 38 months);. Detailed video-electroencephalographic interictal and ictal recording was performed in all patients (invasive electrodes were used in 11 patients);. Ictal onset was shown to be remote from the zone of previous resection in 3 of 15 cases (all 3 extratemporal and in the ipsilateral hemisphere);. Recurrent seizures arose from the area of previous extratemporal resection in 2 of 15 patients, and from the area of previous temporal resection in 10 of 15 patients. Both cases of extratemporal recurrences and 3 of the 10 cases of temporal lobe recurrences in the area of previous resection were associated with residual unresected structural lesion. Of the 10 patients with local temporal recurrence, 6 had proven epileptogenicity in the residual mesial structures, and 4 had residual epileptogenicity in the unresected lateral temporal lobe. The patients have been monitored for 8 to 82 months (mean, 18 months); after the second operation: 7 patients (47%); have remained seizure-free and another 5 (33%); have achieved a reduction in seizure frequency of more than 90%. There was no mortality or significant morbidity in this series. We conclude that the extent and distribution of residual epileptogenicity after failed epilepsy surgery are highly variable. Recurrent intractable seizures usually (but not always); arise from the area of previous resection, and reflect residual structural lesions or epileptogenic foci. Individualized second operations can be safe and effective, and may provide selected patients with “failed cases” another chance at seizure control. Patient selection and the technical aspects of remapping and second operations are discussed.

✓ Analysis of recent reports has suggested that cavernous malformations (CMs) of the brain may have an acquired pathogenesis and a dynamic pathophysiological composition, with documented appearance of new lesions in familial cases and following radiotherapy. The authors report the first case of demonstrated de novo formation of an intramedullary CM following spinal radiation therapy. A 17 year-old boy presented with diabetes insipidus and delayed puberty. Evaluation of endocrine levels revealed hypopituitarism, and magnetic resonance (MR) imaging demonstrated an infundibular mass. The patient underwent a pterional craniotomy and removal of an infundibular germinoma. The MR image of the spine demonstrated normal results. The patient received craniospinal radiation therapy and did well. He presented 5 years later with acute onset of back pain, lower-extremity weakness and numbness, and difficulty with urination. An MR image obtained of the spine revealed an intramedullary T-7 lesion; its signal characteristics were consistent with a CM. The patient was initially managed conservatively but developed progressive myelopathy and partial Brown—Séquard syndrome. Although he received high-dose steroids and bed rest, his symptoms worsened. He underwent a costotransversectomy and excision of a hemorrhagic vascular lesion via an anterolateral myelotomy. Pathological examination confirmed features of a CM. The patient has done well and was walking without assistance within 4 weeks of surgery. De novo genesis of CMs may be associated with prior radiation therapy to the spinal cord.

The extent of resection was assessed in 94 patients who underwent temporal lobectomy for medically intractable complex partial seizures originating from a unilateral seizure focus in the anteromesial temporal lobe. Postoperative magnetic resonance imaging in the coronal plane was used to quantify the extent of resection of lateral and mesiobasal structures according to a 20-compartment model of the temporal lobe. Successful seizure outcome (≥90% reduction in seizure frequency) was accomplished in 83% of the patients (all followed up for more than 1 year; mean duration of follow-up, 25.2 months) and correlated significantly (P<0.05) with the extent of mesiobasal resection, regardless of the extent of resection of lateral structures. Successful seizure outcome was accomplished in 81% of the patients with no structural lesions, and also correlated significantly (P<0.05) with the extent of mesiobasal resection regardless of the extent of lateral resection. A successful seizure outcome was accomplished in 90% of the 21 patients with structural lesions documented by neuroimaging studies. Two patients who underwent extensive lobectomy without resection of the structural lesion had no reduction in seizure frequency postoperatively. We conclude that the most important factor in determining the outcome of temporal lobectomy in patients with unilateral anteromesial temporal lobe epileptogenicity is the extent of resection of structures in the mesiobasal temporal lobe. In patients with structural lesions, lesion resection may be an added contributor to successful seizure outcome. (Neurosurgery 29:55-61, 1991)

No abstract

The natural history of intracranial arterial stenosis is not well understood. The lesions are pathologically quite diverse, and are subject to resolution, progression, or occlusion. The authors undertook an investigation to examine what effects, if any, extracranial-intracranial (EC-IC) bypass surgery had on the evolution of intracranial arterial stenosis in 18 patients undergoing EC-IC bypass procedures for ipsilateral hemispheric ischemia. There was inaccessible internal carotid artery stenosis in 14 patients, and middle cerebral artery stenosis in four patients. Early (within 2 weeks) and late (at 6 months) postoperative angiography was performed in all patients. During the period of the study, there was a significant change in the arterial stenosis in 50% of the patients (nine of 18). The stenotic artery became occluded in four patients while the grafts were widely patent. The occlusion occurred within a few days after the operation in three of the four cases, and was accompanied by an ischemic stroke in these patients. There was improvement or resolution of the stenotic lesion in five patients; the graft became occluded in two of these cases and was patent but showed poor cortical artery filling in the other three. All these patients remained asymptomatic and the change was detected on routine late postoperative angiograms. It is concluded that arterial stenoses should not be viewed as static or inflexible lesions, and that EC-IC bypass procedures can modify the hemodynamic parameters across stenotic lesions, predisposing them to improvement or worsening. This, in turn, may affect bypass patency. Such hemodynamic interactions are accompanied by ischemic symptoms in some patients, and contribute to the relatively higher morbidity associated with EC-IC bypass surgery in the setting of arterial stenosis.