✓ Dura-based spinal arteriovenous malformations (AVM's) are being diagnosed with increasing frequency. The optimal management of such lesions remains a topic of discussion. In an effort to guide this discussion, the authors review their experience with 17 cases of spinal dural AVM treated between January, 1984, and July, 1987. All patients presented with a slowly progressive paraparesis. The abnormalities were initially identified on myelography and confirmed by selective spinal angiography. Fourteen patients underwent endovascular embolization as a primary treatment, and a total of 18 embolization procedures were performed. After all but two of these, obliteration was confirmed at angiography. Patients' symptoms improved following 15 or these procedures but early improvement was not sustained in 10 instances; patients were unchanged after two procedures and worse after one. Follow-up angiography was performed at varying intervals after 15 of the 18 procedures, and recanalization of the previously obliterated spinal dural AVM was demonstrated in 13 instances. Eight patients ultimately underwent surgical treatment of their dura-based spinal AVM. No patient suffered deterioration of symptoms following operation. While embolization may allow angiographic obliteration of a spinal dural AVM and early clinical improvement, for the majority of patients these are not sustained. The average time to treatment failure was 5 months. Newer embolization materials will be necessary to effect permanent treatment in many of these patients.
Michael K. Morgan and W. Richard Marsh
Thoralf M. Sundt Jr., David G. Piepgras and W. Richard Marsh
✓ The authors describe their experience using booster clips to secure the closure of primary clips in the repair of giant and other thick-walled aneurysms. These clips were used for 21 aneurysms in 20 patients, comprising 12% of all aneurysms operated on during the 15-month period of the report, but representing about 50% of all giant aneurysms operated on during the same time frame. These clips are designed to encircle the primary clip and have fixation “shoes” to close upon the jaws of the primary clip. All aneurysms were opened for decompression and thrombectomy when necessary following temporary major vessel occlusion before placement of the primary clip. Cerebral blood flow measurements and continuous electroencephalographic monitoring were utilized to predict the brain's tolerance to temporary ligation of the internal carotid artery (ICA) in those cases with a giant aneurysm arising from that vessel. There were no complications attributable to the periods of intracranial or cervical ICA occlusion; these periods varied but did not exceed 8 minutes for the former nor the tolerance period for the latter, which was calculated as from 5 to 30 minutes. It was necessary to reoperate on two patients and reposition clips because of stenoses or occlusions identified on immediate postoperative angiography. Fifteen patients had normal neurological function at the time of discharge. Three patients had minor deficits which did not prevent employment; two of these were related to a preoperative deficit and one was a complication of delayed ischemia. There were two deaths: one from bleeding complications and probable damage to perforating vessels in a patient operated on under profound hypothermia (the only case in the series so managed), and one from respiratory complications in a patient with severe pulmonary problems.
W. Richard Marsh, Robert E. Anderson and Thoralf M. Sundt Jr.
✓ The adverse effect of a minimal cerebral blood flow (CBF) in models of global ischemia has been noted by many investigators. One factor believed important in this situation is the level of blood glucose, since a continued supply of this metabolite results in increased tissue lactate, decreased brain pH, and increased cell damage. The authors have extended these observations to a model of focal incomplete ischemia. Brain pH was measured in fasted squirrel monkeys in regions of focal incomplete ischemia after transorbital occlusion of the middle cerebral artery (MCA). In both control and hyperglycemic animals, CBF was reduced to less than 30% of baseline. At 3 hours after MCA occlusion, brain pH in the control group was 6.66 ± 0.68 as compared to 6.27 ± 0.26 in the glucose-treated group. This difference was statistically significant by Student's unpaired t-test (p < 0.05). Thus, hyperglycemia results in decreased tissue pH in regions of focal incomplete cerebral ischemia in monkeys.
Michael D. Partington, Daniel A. Rüfenacht, W. Richard Marsh and David G. Piepgras
✓ The authors report a series of seven patients with myelopathy who were found to have spinal dural arteriovenous (AV) fistulas in which the nidus was located at some distance from the spinal cord. The nidus was intracranial in three cases and involved a sacral nerve root sheath in the other four, in each case, the arterialized draining vein led into the coronal plexus of medullary veins. A lack of normal draining radicular veins was noted in all cases. Magnetic resonance images were obtained in four patients and demonstrated spinal cord tissue changes only in the lower thoracic cord in three cases and in the cervical cord in one, all consistent with an ischemic process secondary to venous hypertension. Five patients were managed surgically by division of the draining vein, with improvement of the neurological deficit in all. One patient was treated by embolization alone and had stabilization of her deficit. The remaining patient in the series died of unrelated systemic disease before the spinal dural AV fistula could be treated.
These cases support the theory that venous hypertension is the dominant pathophysiological mechanism involved in spinal dural AV fistulas independent of their location. In patients with a suspected spinal dural AV fistula, lumbar and thoracic spinal angiography will reveal the site of the fistula in the majority of cases (88% in this series). In the remaining patients, the possibility of a remote fistula must be considered. The lack of normal venous drainage of the cord following injection in the artery of Adamkiewicz is the most reliable indicator of venous hypertension in the cord and can be helpful in making the decision to proceed with a search for a cranial or sacral arterial supply.
Wouter I. Schievink, John Huston III, Vicente E. Torres and W. Richard Marsh
✓ Autosomal dominant polycystic kidney disease (ADPKD) is a systemic disorder well known for its association with intracranial aneurysms. A series of patients with ADPKD who were screened for the presence of an intracranial aneurysm were reviewed and found to include an unexpectedly high number with intracranial arachnoid cysts.
Among 247 patients with ADPKD who underwent magnetic resonance imaging (180 cases) or high-resolution contrastenhanced computerized tomography (67 cases), there were 151 women and 96 men with a mean age of 44 years. Intracranial arachnoid cysts were found in 20 patients (8.1%) with ADPKD compared to two (0.8%) in a control group without ADPKD matched for age, sex, and method of imaging (p < 0.0001). Multiple intracranial arachnoid cysts were found in two patients. Polycystic liver disease was present in 17 (85.0%) of the 20 patients with intracranial arachnoid cysts compared to 119 (52.4%) of the 227 patients without (p < 0.004). Pineal cysts were found in two patients (0.8%) and choroid plexus cysts were found in three patients (1.2%) but this was not different from the control population. None of the intracranial cysts was symptomatic and none was treated surgically.
Intracranial arachnoid cysts are a relatively frequent incidental finding in patients with ADPKD, providing further support for the systemic nature of this disease. In the authors' experience with approximately 1500 patients with ADPKD, no complication has been encountered from an intracranial arachnoid cyst, suggesting that asymptomatic intracranial arachnoid cysts in patients with ADPKD require no treatment.
Transient postictal magnetic resonance imaging abnormality of the corpus callosum in a patient with epilepsy
Case report and review of the literature
Aaron A. Cohen-Gadol, Jeffrey W. Britton, Clifford R. Jack Jr., Jonathan A. Friedman and W. Richard Marsh
✓ Transient neuroimaging abnormalities associated with seizure activity have received little attention in the literature. The authors report a focal magnetic resonance (MR) imaging abnormality of the corpus callosum in a patient following a secondary generalized seizure. A 27-year-old right-handed man presented with a history of medically refractory partial seizures since the age of 1 year. The results of an MR imaging study obtained 4 months prior to the patient undergoing video-electroencephalography monitoring were unremarkable. After the patient discontinued all antiepileptic medications, a secondary generalized seizure of right temporal origin was recorded. Five days later, repeated MR imaging revealed a nonenhancing 14 × 11—mm ovoid hyperintense lesion in the splenium of corpus callosum. The patient was asymptomatic, and his neurological and neurocognitive examinations remained unremarkable. Follow-up MR imaging 5 weeks and 1 year later demonstrated near-complete resolution of the lesion. Benign and transient abnormalities in the splenium can occur as a periictal phenomenon. A high index of suspicion and follow-up imaging may prevent further unwarranted intervention.
Fredric B. Meyer, W. Richard Marsh, Edward R. Laws Jr. and Frank W. Sharbrough
✓ The results of temporal lobectomy for medically refractory seizures are analyzed in 29 boys and 21 girls with a mean age of 15.8 years. The average age at onset of seizures was 7.5 years, and the time between onset and surgery averaged 8.3 years. Postoperatively, 27 patients (54%) were seizure-free, 12 patients (24%) had only occasional auras without loss of consciousness, five patients (10%) had fewer seizures, and six (12%) were unchanged. Therefore, 78% were essentially seizure-free and 88% benefited significantly from the operation. There was no significant change in the Wechsler Intelligence Scale scores before and after surgery; however, the shorter the time between seizure onset and surgery, the greater the likelihood of improvement in verbal and perceptual intelligence quotient. Social outcome was significantly improved, and a large percentage of patients were either in school or actively employed. Early consideration of temporal lobectomy in children with medically refractory seizures is recommended.
Thoralf M. Sundt Jr., David G. Piepgras, W. Richard Marsh and Nicolee C. Fode
✓ The authors report their experience with the use of saphenous vein bypass grafts for treating advanced occlusive disease in the posterior circulation (77 patients, all of whom had failed medical management and showed severe ischemic symptoms), deteriorating patients with giant aneurysms of the posterior circulation (nine patients), progressive ischemia in the anterior circulation (26 patients, none of whom had a normal examination), and giant aneurysms in the anterior circulation (20 patients, all of whom presented with mass effect or subarachnoid hemorrhage). Graft patency in the first 65 cases treated was 74%. However, after significant technical changes of vein-graft preparation and construction of the proximal anastomosis, patency in the following 67 cases was 94%. Excellent or good results (including relief of deficits existing prior to surgery) were achieved in 71% of patients with advanced occlusive disease in the posterior circulation, 44% of those with giant aneurysms of the posterior circulation, 58% of those with ischemia of the anterior circulation, and 80% of those with giant aneurysms of the anterior circulation. Mean graft blood flow at surgery in the series was 100 ml/min for posterior circulation grafts and 110 ml/min for anterior circulation grafts. Experience to date indicates that this is a useful operation, and is particularly applicable to patients who are neurologically unstable from advanced intracranial occlusive disease in the posterior circulation or with giant aneurysms in the anterior circulation. The risk of hyperperfusion breakthrough with intracerebral hematoma restricts the technique in patients with progressing ischemic symptoms in the anterior circulation, and the intolerance of patients with fusiform aneurysms in the posterior circulation to the iatrogenic vertebrobasilar occlusion limits the applicability of this approach to otherwise inoperable lesions in that system.
Jamie J. Van Gompel, W. Richard Marsh, Fredric B. Meyer and Gregory A. Worrell
Microsurgical resection of supratentorial cavernomas associated with intractable epilepsy is performed frequently. Despite its common occurrence, little is known about patient perceptions of microsurgical resection for cavernomas. This survey study was performed to investigate patient perceived outcome after surgery for cavernomas associated with intractable epilepsy.
The authors' surgical database was searched for cavernoma resection performed between 1971 and July of 2006. Of the initial 173 patients identified, 102 met criteria for medically intractable seizures. These 102 patients were then mailed a survey to determine follow-up and patient satisfaction. Thirty-nine surveys were returned as undeliverable, and 30 (48%) of the remaining 63 patients responded.
The average age at surgery for patients responding to this survey was 40 ± 16 years compared with 35 ± 15 years for all 102 patients. At prolonged follow-up, 87% of patients reported being seizure-free. Of those with seizures, 2 (7%) reported being nearly seizure-free (rare disabling seizures), 2 (7%) believed they had a worthwhile improvement in seizure frequency, and no patient (0%) in this series believed they did not have a worthwhile improvement in seizure frequency. Ninety percent of responders stated they definitely, and 10% probably, would have surgery again. No patient responded that they probably or definitely would not have epilepsy surgery. Mean clinical follow-up was 36 ± 8 months and survey follow-up was 97 ± 13 months for these 30 patients. Use of the mail-in survey increased follow-up length 2.7 times longer compared with clinical follow-up.
It is clear from this select group of survey responders that patients undergoing surgery for cavernomas associated with medically intractable epilepsy are happy they underwent surgery (100%) and had excellent surgical outcomes (87% seizure-free) at prolonged follow-up of 97 ± 13 months. These survey results support that microsurgical resection for cavernomas is highly effective and significantly improves these patients' quality of life.
Aaron A. Cohen-Gadol, Jacqueline A. Leavitt, James J. Lynch, W. Richard Marsh and Gregory D. Cascino
Object. In this prospective study the authors investigated the incidence and natural history of postoperative diplopia in patients undergoing anterior temporal lobectomy (ATL) and amygdalohippocampectomy for medically intractable mesial temporal lobe epilepsy.
Methods. Forty-seven patients scheduled for ATL for medically refractory seizures were examined preoperatively, 2 to 7 days postoperatively, and 3 to 6 months postoperatively. Ophthalmological examination including pupillary measurements, stereoacuity measurements, palpebral fissure measurements, vertical fusional amplitudes, Lancaster red green testing, visual field testing, and alternate cover testing was performed. Antiepileptic drug levels were monitored.
Nine (19%) of 47 patients developed diplopia postoperatively. The diplopia was caused by trochlear nerve palsy in every case. No oculomotor nerve dysfunction was documented. Trochlear nerve function recovered completely in all patients within 3 to 6 months postoperatively.
Conclusions. Postoperative diplopia following ATL occurs more often than previously thought and is primarily due to trochlear nerve dysfunction. Awareness of this transient complication is important in preoperative patient counseling.