✓ The surgical and computerized tomographic myelography (CTM) features of 134 stenotic foraminal canals were correlated retrospectively in 95 patients. The myelographic site of stenosis was the entrance to the foraminal canal in 70 cases (52%) and the canal itself in 37 (28%); the site was not identified definitively in 27 (20%). At the entrance to the foraminal canal, encroachment on the adjacent nerve root was by a cartilaginous cap in 10 cases (8%), a bony osteophyte in 17 (13%), a synovial cyst in one (1%), and a combination of a bony and cartilaginous osteophyte in 42 (31%). The diagnostic features of stenosis within the foraminal canal were more variable. Small bone spurs arising from the uncovertebral process encroached on the anterior aspect of the foramen in 29 instances (22%), accompanied in all cases by either a congenitally narrow canal (in 16) or a diffuse osteophytically narrowed canal (in 13); osteophytes arising from the superior facet in eight instances (6%) were larger and encroached on the posterior aspect of the foramen. Diagnosis on the basis of CTM is difficult because stenosis was readily evident as a bone spur in only 13% of cases, could not be distinguished from prolapsed disc in 39%, had to be differentiated from a congenitally narrow foraminal canal in 27%, and was frankly missed in 20% of the instances of stenosis.
O. Wayne Houser, Burton M. Onofrio, Gary M. Miller, W. Neath Folger, Patsy L. Smith and Douglas A. Kallman
Michael J. Ebersold, O. Wayne Houser and Lynn M. Quast
✓ The records of 1005 patients who underwent iopamidol myelography between January and September, 1988, were reviewed. In this group, 50 patients had histories suggestive of untoward sequelae associated with iodine intake, contact, or administration. The charts of these patients were carefully reviewed, and none of them had any reactions or sequelae suggestive of toxicity or an allergic response after iopamidol myelography. It is concluded that, even in patients with a previous history suggestive of intolerance to iodine administration, iopamidol myelography is generally a safe procedure.
John L. D. Atkinson, Thoralf M. Sundt Jr., O. Wayne Houser and Jack P. Whisnant
✓ A retrospective angiographic analysis was designed to extrapolate the frequency of angiographically defined asymptomatic intracranial aneurysms in the anterior circulation from a relatively unbiased clinical series. A total of 9295 angiograms were reviewed from January, 1980, to January, 1987, and, based on these, 278 patients with minimal bias for the presence of an aneurysm were selected. Three patients were found to have incidental aneurysms; thus, the angiographic frequency of patients with asymptomatic aneurysms in this series was 1%. This patient population is skewed toward the older age groups and probably over-represents the incidence of these aneurysms in the population at large. Comparing current subarachnoid hemorrhage statistics and the low frequency of asymptomatic aneurysms suggests that a larger percentage of these aneurysms than was previously thought subsequently rupture. This study contrasts sharply with previous reports quoting a high incidence of aneurysms, and significantly alters the concept and treatment of this disease.
Bahram Mokri, David G. Piepgras and O. Wayne Houser
✓ Traumatic dissections of the extracranial internal carotid artery (ICA) in 18 patients aged 19 to 55 years were studied. All had suffered blunt head or neck injury of marked or moderate severity; motor-vehicle accidents were the leading cause of the injury. Delayed focal cerebral ischemic symptoms were the most common presenting symptoms. Less commonly noted was focal unilateral headache associated with oculosympathetic paresis or bruit. Following a head injury, the abrupt onset of focal cerebral symptoms after a lucid interval should raise the suspicion of arterial injury, particularly when computerized tomography fails to show abnormalities that would explain the evolving neurological deficits on the basis of direct trauma to the brain. Unilateral headaches, oculosympathetic palsy, and bruits also help in establishing the diagnosis. Focal cerebral ischemic symptoms may develop months or years after the initial trauma. These delayed symptoms are caused by embolization from a thrombus within a residual dissecting aneurysm. Common angiographic findings, in decreasing order of frequency, are: aneurysm, stenosis of the lumen, occlusion, intimal flap, distal branch occlusion (embolization), and slow ICA-to-middle cerebral artery flow. Although two patients died as the result of massive cerebral infarction and edema and some were left with severe neurological deficits, most made a good recovery. Residual dissecting aneurysms and occlusion seem to occur more frequently with traumatic dissections than with spontaneous dissections of the extracranial ICA.
Theodore C. Larson III, O. Wayne Houser, Burton M. Onofrio and David G. Piepgras
✓ The records of five patients with primary melanoma of the spinal cord were reviewed. The tumor most frequently presented as an intramedullary middle or lower thoracic cord lesion. The average duration of symptoms before pathological diagnosis was 29 months, and the average survival after laminectomy and radiation therapy was 6 years 7 months. The findings in this series, when compared with those in the literature, suggest that primary spinal melanoma is a more indolent malignancy than previously reported or than melanoma metastatic to the central nervous system.
O. Wayne Houser, Burton M. Onofrio, Glenn S. Forbes and H. L. Baker Jr.
✓ Chemonucleolysis was performed in 103 patients for lumbar disc prolapse. Multiple (two) interspaces were injected in only seven patients. Radiographically, all patients had myelographic or computerized tomography evidence of disc prolapse. Eighty-seven of 100 patients who were available for follow-up review had improved. Ten of 13 patients with persistent symptoms required a laminectomy. Altered spinal alignment was evident in five of the 13 patients with persistent symptoms: retrolisthesis in three and myelographic disc defect on the convex aspect of the scoliosis in two. Review of radiographic studies was carried out in an attempt to establish guidelines for patient selection so as to decrease the rate of failure in chymopapain treatment.
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.
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.
Thomas J. Rosenbaum, O. Wayne Houser and Edward R. Laws
✓ The authors report a case of pituitary apoplexy occurring several hours after carotid angiography. The event was associated with stupor, focal headache, and left hemiparesis. Repeat angiography demonstrated intracranial occlusion of the right internal carotid artery. At surgery, a hemorrhagic pituitary adenoma was found to be compressing the internal carotid artery, and the removal of the tumor resulted in restoration of flow. The mechanism, presenting symptoms and signs, and treatment of pituitary apoplexy causing compression of a major vessel are discussed.