✓ Arteriovenous malformations (AVM's) of lateral and sigmoid sinuses are acquired lesions evolving from a previously thrombosed dural sinus. Their natural history is usually that of gradual progression and hence surgery is frequently necessary. The preferred surgical treatment is complete excision coupled with packing of the sigmoid sinus. The operative approach is illustrated and discussed in detail. Results and complications are reviewed in 27 patients whose symptomatology had progressed under conservative management; 22 of these cases harbored primary lesions and five had recurrences. There were 22 excellent, one good, and two poor results (both of the latter from blindness that preceded surgery). There were two deaths, both in patients previously operated on with incomplete removal or obliteration of the AVM by attempted embolization.
Thoralf M. Sundt Jr. and David G. Piepgras
Operative experience with 80 cases
Thoralf M. Sundt Jr. and David G. Piepgras
✓ The authors report experience with the surgical management of 80 giant intracranial aneurysms (> 2.5cm in diameter) during a 10-year period in which they performed 594 operations for aneurysms. The overall incidence of giant aneurysms was 13% but varied according to location: 20% of aneurysms of the internal carotid artery (ICA); 13% of middle cerebral artery (MCA) aneurysms; 1% of anterior cerebral artery (ACA) aneurysms; 15% of aneurysms of the basilar artery caput (BAC); and 18% of vertebrobasilar trunk(VB) aneurysms. Twenty-five patients had a subarachnoid hemorrhage (SAH), 49 had mass effect from the aneurysm, and six had ischemic events. There was no apparent difference in results related to the presence or absence of an SAH. Poor results were attributable to the operation except in the two cases of ACA aneurysm in which preexisting dementia persisted. Mortality was 4% and morbidity was 14%, varying from a combined low morbidity-mortality of 8% for ICA lesions to a high of 50% for BAC aneurysms. During the period of the study, different techniques were developed in an attempt to lower the risks of surgery.Ultimately ICA aneurysms were monitored with cerebral blood flow measurements and electroencephalography before and after temporary ICA ligation, then approached following resection of the anterior clinoid or treated with bypass in combination with ICA ligation. Aneurysms of the MCA were either opened during temporary MCA occlusion or resected in combination with a bypass procedure. Bypass grafts and circulatory arrest with extracorporeal circulation may have a role in giant aneurysms of the posterior circulation.
Thoralf M. Sundt Jr. and David G. Piepgras
✓ The results, complications, and technical aspects of occipital to posterior inferior cerebellar artery (PICA) bypass surgery are reviewed. Patients were divided into two groups: those considered to be a high risk for posterior circulation infarct but not disabled by the symptoms or deficits (eight patients), and those moderately or severely disabled at the time of admission (eight patients). Postoperative angiography revealed that 15 of the 16 grafts were patent. In 10 of the 15 patent grafts, the bypass graft served as a sole or major blood supply of the vertebral basilar system; in five patients, flow was limited to the distribution of the PICA. Eight patients achieved full employment or normal activity, six were improved but did not return to full employment, and two patients were unchanged. Ataxia was the major residual deficit in these patients.
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.
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.
David G. Piepgras, Thoralf M. Sundt Jr., Ashvin T. Ragoonwansi and Lorna Stevens
✓ A series of 280 cases of cerebral arteriovenous malformations (AVM's) treated surgically between June, 1970, and June, 1989, is reviewed with particular focus on the preoperative seizure history and follow-up seizure status. Follow-up evaluation (mean duration 7.5 years) was achieved in 98% of cases and was accomplished through re-examinations, telephone interviews, and written questionnaires. Overall, 89% of the surviving patients with a follow-up period of greater than 2 years were free of seizures at last examination.
Of the 280 patients in this series. 163 had experienced no seizures preoperatively. A recent follow-up study (with a minimum duration of 2 years or to death) was available in 157 of these 163 cases; 21 patients had died. Of the 136 surviving patients, only eight (6%) were having new ongoing seizures. In the 128 (94%) who had remained seizure-free, 73% were receiving no anticonvulsant agents while 27% were taking anticonvulsant prophylaxis. The 2-year minimum follow-up study in 110 of the 117 patients with preoperative seizures revealed that eight (7%) had died. Of the 102 surviving patients, 85 (83%) were seizure-free (with 48% no longer receiving anticonvulsant therapy), while 17 (17%) still suffered intermittent seizures. However, of these 17 patients, 13 reported their seizures to be improved compared to preoperatively; the seizures were the same in two patients and were worse in two patients.
An actuarial analysis was conducted comparing the life expectancy of patients following surgery for AVM's with the expected survival of a general white population of the same age and sex in the West Northcentral region of the United States. No statistically significant difference was found. There were seven perioperative deaths (three from cerebral hemorrhage, two from pulmonary emboli, and two from obstruction of venous drainage) and 22 deaths during the follow-up period. Of these 22 deaths, the cause was unknown in four patients, apparently unrelated to the AVM in 13, and directly or indirectly related to the patient's neurological condition prior to surgery or due to surgery performed for resection of the AVM in five.
There was a statistically significant relationship between the size and location of the AVM and the clinical presentation. Patients with small AVM's (< 3 cm) were more likely to present with hemorrhage whereas those with large AVM's were more likely to present with seizures.
Conclusions from this study are: 1) there is a low incidence of a new seizure disorder following surgery: 2) chances for resolution or control of a pre-existing seizure disorder are good: 3) although resolution of seizures or seizure control was achieved postoperatively in AVM's of all sizes, this benefit was highest in smaller as opposed to larger AVM's; and 4) ultimately, there is a good capacity for recovery from pre-existing neurological deficits or those resulting from surgery.
Fredric B. Meyer, David G. Piepgras, Thoralf M. Sundt Jr. and Takehiko Yanagihara
✓ Twenty cases treated with emergency embolectomy for acute occlusion of the middle cerebral artery were reviewed. There were 10 males and 10 females, with an average age of 55 years. The left middle cerebral artery was involved in 17 patients and the right in three. Flow was restored in 16 patients (75%). The embolus originated in the heart in seven, the carotid artery in seven, the aorta in three, an aneurysm in one, and an indeterminate source in two. It was technically most difficult to achieve patency with atheromatous emboli from the aorta. Two patients (10%) had an excellent result with no neurological deficit, five (25%) were left with a minimal deficit but were employable, seven (35%) had a fair result but were still independent and employable, four (20%) did poorly, and two (10%) died. Patients with an associated ipsilateral carotid artery occlusion did poorly. Collateral flow, as judged from preoperative angiograms, was the best predictor of outcome.
Thoralf M. Sundt Jr., David G. Piepgras, O. Wayne Houser and J. Keith Campbell
✓ The authors report their initial experience with the use of interposition saphenous vein grafts between the external carotid artery and the proximal posterior cerebral artery. The indications, results, and technical aspects of the operation are reviewed. All patients accepted for surgery were at high risk for a posterior circulation infarct, and all patients with ischemic symptomatology had continued to progress while on anticoagulant drugs or anti-platelet agents. Thus, all patients were at high risk, and 11 of the 14 patients operated on were confined to bed before surgery. Intraoperative graft flows varied from 35 to 170 ml/min, and postoperative graft flows ranged from 75 to 311 ml/min in the patent grafts. There were three early graft occlusions and two late graft occlusions; these all occurred in patients with relatively low flows at the time of surgery (40 ml/min or lower). Subdural hygroma was the next most frequent complication to graft occlusion. It was thought to be caused by the pulsating graft anastomosed to a major vessel through a small opening in the basal arachnoid, which provided a new path for cerebrospinal fluid flow in patients with a degree of preexisting atrophy. One patient with a large aneurysm in the posterior circulation underwent proximal intracranial clipping of the vertebral artery and bypass grafting simultaneously. There were seven excellent results and two good results in nine patients in whom the graft remained patent. In the five patients with graft occlusion, there were two minor strokes, two major strokes, and one death.
David G. Piepgras, Michael K. Morgan, Thoralf M. Sundt Jr., Takehiko Yanagihara and Lynn M. Mussman
✓ A series of 14 patients with intracerebral hemorrhage after carotid endarterectomy is reviewed. This complication occurred in 0.6% of 2362 consecutive carotid endarterectomies performed at the Mayo Clinic from 1972 through 1986. All hemorrhages occurred within the first 2 weeks after operation and were ipsilateral to the side of the operation. Eight patients died, and only two made a good recovery. Significant risk factors are hypertension and chronic hemispheric hypoperfusion with impaired autoregulation. The “normal pressure-hyperperfusion breakthrough” syndrome was considered to be operative in 12 of the 14 patients. Nine patients had documented hyperperfusion (at least 100% increase of baseline cerebral blood flow) at the time of surgery. In an additional three patients, normal perfusion-pressure breakthrough was inferred by the clinical course and radiological findings, as well as by the absence of alternative explanations. Patients at risk for postendarterectomy intracerebral hemorrhage include those who have a clinical history suggestive of hemodynamic cerebral ischemia, severe carotid stenosis with limited hemispheric collateral flow, and postendarterectomy hyperperfusion, as measured by intraoperative cerebral blood flow. To minimize the risk of hemorrhage in these patients, strict maintenance of blood pressure at normotensive or even relatively hypotensive levels during the intraoperative and early postoperative periods is advised.
Thoralf M. Sundt Jr., Bruce W. Pearson, David G. Piepgras, O. Wayne Houser and Bahram Mokri
✓ Results, complications, and operative techniques of the surgical management of 20 aneurysms of the distal extracranial internal carotid artery (ICA) in 19 patients are reviewed. The proximity of these aneurysms to the styloid process is not considered as a chance occurrence, and the possibility is raised that these lesions are related to trauma from that structure. False aneurysms from spontaneous dissections are believed to occur only in those dissections that begin distally; they are not found in dissections that begin proximally. Treatment was individualized and dependent upon: 1) the size and location of the aneurysm; 2) symptomatology; and 3) hemodynamic considerations based upon intraoperative cerebral blood flow (CBF) measurements determined from the clearance of xenon-133 injected into the ipsilateral ICA. Methods of treatment included: resection of the aneurysm with placement of an interposition saphenous vein graft in seven patients; resection of the aneurysm with end-to-end anastomosis of the ICA in five; ICA ligation in three; clipping of the aneurysm in one; and extracranial-to-intracranial bypass in four. One patient sustained a postoperative cerebral ischemic complication from embolization which resulted in a mild permanent impairment in right hand dexterity. There were no other cerebral ischemic complications in the group, largely attributable, it is thought, to the use of intraoperative CBF measurements and continuous electroencephalograms. Four patients had transient dysphagia from traction damage to the pharyngeal and superior laryngeal nerves, and one patient with preoperative difficulty in swallowing required a gastrostomy. Long-term results have been excellent. Use of the operating microscope facilitated the suturing of the distal anastomosis in cases in which the ICA was reconstructed by an interposition vein graft or end-to-end anastomosis.