Vasospasm: A Personal Odyssey.

Key references on the history of vasospasm, a selected bibliography of B.K.A. Weir and colleagues on aneurysms and vasospasm and commentary on the "New World of Thought" are provided.

A history of neurosurgery in Canada.

Canada existed for more than half a century before there were glimmerings of modern neurosurgical activity. Neurosurgery had advanced significantly in Europe and the United States prior to its being brought to Toronto and Montreal from American centers. The pioneers responsible for the rapid evolution in practice, teaching and research are described. The interplay of scientific, professional, demographic and economic forces with general historical trends has produced dramatic changes in the way that neurosurgery is now practiced.

Multiple sclerosis - a vascular etiology?

From the earliest pathological studies the perivenular localization of the demyelination in multiple sclerosis (MS) has been observed. It has recently been suggested that obstructions to venous flow or inadequate venous valves in the great veins in the neck, thorax and abdomen can cause damaging backflow into the cerebral and spinal cord circulations. Paolo Zamboni and colleagues have demonstrated abnormal venous circulation in some multiple sclerosis patients using non-invasive sonography and invasive venography. Furthermore, they have obtained apparent clinical improvement or stabilization by endovascular ballooning of points of obstruction in the great veins in some, at least temporarily. If non-invasive observations by others validate their initial observations of a significantly increased prevalence of venous obstructions in MS then trials of angioplasty/stenting would be justified in selected cases in view of the biological plausibility of the concept.

The aspect ratio (dome/neck) of ruptured and unruptured aneurysms.

OBJECT: In this retrospective study the authors examined the aspect ratio (AR; the maximum dimension of the dome/width of the neck of an aneurysm) and compared the distribution of this ratio in a group of ruptured and unruptured aneurysms. A similar comparison was performed in relation to the maximum dimension of the aneurysm alone. The authors sought to evaluate the utility of these measures for differentiating ruptured and unruptured aneurysms. METHODS: Measurements were made of 774 aneurysms in 532 patients at three medical centers. One hundred twenty-seven patients harbored only unruptured lesions, 290 only ruptured lesions, and 115 both ruptured and unruptured lesions. Cases were included if angiograms were available for measurement and the status of the individual patient's aneurysm(s) was known. The odds of a lesion falling in the ruptured aneurysm group increased with both the lesion's maximum size and the AR. The odds ratio for rupture rose progressively only for the AR. The distribution curves showed that ruptured aneurysms were larger and had greater ARs. The mean size of unruptured aneurysms was 7 mm and that of ruptured ones was 8 mm; the corresponding mean ARs were 1.8 and 3.4, respectively. The odds of rupture were 20-fold greater when the AR was larger than 3.47 compared with an AR less than or equal to 1.38. Only 7% of ruptured aneurysms had an AR less than 1.38 compared with 45% of unruptured lesions. CONCLUSIONS: The AR is probably a useful index to calculate. A high AR might reasonably influence the decision to treat actively an unruptured aneurysm independent of its maximum size. Prospective studies are warranted.

Randomized, pilot study of intermittent pneumatic compression devices plus dalteparin versus intermittent pneumatic compression devices plus heparin for prevention of venous thromboembolism in patients undergoing craniotomy.

BACKGROUND: Unfractionated heparin and the low molecular weight heparin, dalteparin, are used for prophylaxis against venous thromboembolism in patients undergoing craniotomy. These drugs were compared in a randomized, prospective pilot study comparing intermittent pneumatic compression devices plus dalteparin to intermittent pneumatic compression devices plus heparin. METHODS: One hundred patients undergoing craniotomy were randomly allocated to receive perioperative prophylaxis with subcutaneous (SC heparin, 5000 units every 12 hours, or dalteparin, 2,500 units once a day, begun at induction of anesthesia and continued for 7 days or until the patient was ambulating. Entry criteria were age over 18 years, no deep vein thrombosis (DVT) preoperatively as judged by lower limb duplex ultrasound and no clinical evidence of pulmonary embolism preoperatively. Patients with hypersensitivity to heparin, penetrating head injury or who refused informed consent were excluded. Patients underwent a duplex study 1 week after surgery and 1 month clinical follow-up. All patients were treated with lower limb intermittent pneumatic compression devices. RESULTS: There were no differences between groups in age, gender, and risk factors for venous thromboembolism. There were no differences between groups in intraoperative blood loss, transfusion requirements or postoperative platelet counts. Two patients receiving dalteparin developed DVT (one symptomatic and one asymptomatic). No patient treated with heparin developed DVT and no patient in either group developed pulmonary embolism. There were two hemorrhages that did not require repeat craniotomy in patients receiving dalteparin and one that did require surgical evacuation in a patient treated with heparin. Drug was stopped in two patients treated with dalteparin because of thrombocytopenia. None of these differences were statistically significant. CONCLUSION: There was no significant difference in postoperative hemorrhage, venous thromboembolism or thrombocytopenia between heparin and dalteparin. The results suggest that, given the small sample size of this trial, both drugs appear to be safe and the incidence of venous thromboembolism by postoperative screening duplex ultrasound appears to be low when these agents are used in combination with intermittent pneumatic compression devices.

Rupture of middle cerebral artery aneurysm in a neonate: case report and review of the literature.

Intracranial hemorrhage because of rupture of a cerebral aneurysm is extremely rare in the neonatal period. Delayed diagnosis contributes to high mortality and morbidity. The authors report an extremely rare case of a middle cerebral artery aneurysm diagnosed and treated shortly after birth. Extensive review of the literature is presented. The patient died 4 years after surgery.

Unruptured intracranial aneurysms: a review.

OBJECT: In this article, pathological, radiological, and clinical information regarding unruptured intracranial aneurysms is reviewed. METHODS: Treatment decisions require that surgeons and interventionists take into account information obtained in pathological, radiological, and clinical studies of unruptured aneurysms. The author has performed a detailed review of the literature and has compared, contrasted, and summarized his findings. Unruptured aneurysms may be classified as truly incidental, part of a multiple aneurysm constellation, or symptomatic by virtue of their mass, irritative, or embolic effects. Unruptured aneurysms with clinical pathological profiles resembling those of ruptured lesions should be considered for treatment at a smaller size than unruptured lesions with profiles typical of intact aneurysms, as has been determined at autopsy in patients who have died of other causes. The track record of the surgeon or interventionist and the institution in which treatment is to be performed should be considered while debating treatment options. In cases in which treatment is not performed immediately, ongoing periodic radiological assessment may be wise. Radiological investigations to detect unruptured aneurysms in asymptomatic patients should be restricted to high-prevalence groups such as adults with a strong family history of aneurysms or patients with autosomal dominant polycystic kidney disease. All patients with intact lesions should be strongly advised to discontinue cigarette smoking if they are addicted. CONCLUSIONS: The current state of knowledge about unruptured aneurysms does not support the use of the largest diameter of the lesion as the sole criterion on which to base treatment decisions, although it is of undoubted importance.

Sizes of ruptured and unruptured aneurysms in relation to their sites and the ages of patients.

OBJECT: The authors explore the risk of rupture in aneurysms categorized by size. METHODS: A computerized database of 945 patients with aneurysms treated between 1967 and 1987 was retrospectively established. All available clinical and radiological studies were abstracted. Because of the recent interest in the size of intracranial aneurysms in relation to their likelihood of rupture, the database was searched with respect to this parameter. In 390 patients representing 41% of all cases, aneurysms were measured by neuroradiologists at the time of diagnosis. In 78% of the 945 patients there was only one aneurysm, and of the 507 aneurysms that were measured, 60% were solitary. Of all patients, 86% had ruptured aneurysms. The average age of all patients was 47 years, and for those with ruptured aneurysms it was 46 years. Of the ruptured aneurysms, 77% were 10 mm or smaller, compared with 85% of the unruptured aneurysms. It was found that 40.3% of the ruptured aneurysms were on the anterior cerebral artery or anterior communicating artery, compared with 13% of the unruptured aneurysms. None of the cavernous internal carotid artery (ICA) aneurysms were ruptured and 65% of the ophthalmic artery (OphA) aneurysms were. Of the unruptured aneurysms, 15% were located in the cavernous ICA or the OphA. Of the ruptured aneurysms, 29% were on the middle cerebral artery, compared with 36% of the unruptured aneurysms. The mean size of ruptured and unruptured aneurysms showed no statistically significant increase with patient age, although the difference in size between the ruptured and unruptured aneurysms decreased with increasing age. The mean size of all ruptured aneurysms (10.8 mm) was significantly larger than the mean size of all unruptured aneurysms (7.8 mm, p < 0.001); the median sizes were 10 mm and 5 mm, respectively. The size of ruptured aneurysms in patients who died in the hospital was significantly larger than those in the patients who survived (12 mm compared with 9.9 mm, p = 0.004). Symptomatic unruptured aneurysms were significantly larger than incidental unruptured aneurysms (14.6 mm compared with 6.9 mm, p = 0.032), which were, in turn, larger than aneurysms that were unruptured and part of a multiple aneurysm constellation. Both ruptured and unruptured aneurysms were larger in male than in female patients, but not significantly. CONCLUSIONS: Site and patient age, as well as lesion size, may affect the chance of rupture.