Blood clot resolution in human cerebrospinal fluid: evidence of first-order kinetics.

OBJECTIVE: To determine the kinetics of blood clot resolution in human cerebrospinal fluid. METHODS: Computed tomographic scans of 17 adult patients with intraventricular hemorrhages were analyzed. Intraventricular clot volume was determined and analyzed over time to determine both a standardized percentage rate and an absolute rate of clot resolution. Results were analyzed by use of regression for cross sectional time-series data. To determine the kinetics of intraventricular clot resolution, the effect of the clot volume on the percentage rate of clot resolution, clot half-life, and absolute rate of clot resolution was analyzed. The potential effect of age, sex, type of hemorrhage, and treatment with external ventricular drainage on the percentage rate of clot resolution was assessed. RESULTS: The percentage rate of clot resolution was 10.8% per day (95% confidence interval, 9.05-12.61 %), and it was independent of initial clot volume, age, sex, type of underlying hemorrhage, and use of external ventricular drainage. The absolute rate of clot resolution varied directly with the maximal clot volume (R2 = 0.88; P < 0.001). The percentage clot resolution data are consistent with events during the first 24 to 48 hours that antagonize clot resolution. CONCLUSION: These findings demonstrate that intraventricular blood clot resolution in patients with intraventricular hemorrhage follows first-order kinetics. The thrombolytic enzyme system responsible for intraventricular clot resolution seems to be saturated at 24 to 48 hours after the initial hemorrhage.

History of peripheral nerve surgery techniques.

The nineteenth century witnessed significant discoveries in the understanding of the peripheral nerve response to injury. Unfortunately, these discoveries were not widely accepted and several physiologically implausible nerve repair procedures survived into the first decades of the twentieth century. The surgical experience in World War I winnowed out most of these unsound techniques and laid the foundations for modern direct nerve repair. The surgical experience of World War II led to a rational classification of nerve injuries and refined the timing for surgical intervention. Major postwar developments that led to the modern era include improved nerve grafting techniques, intraoperative nerve action potential recording, and strategies for the repair of brachial plexus lesions.

Treatment of intraventricular hemorrhage with urokinase : effects on 30-Day survival.

BACKGROUND AND PURPOSE: Intraventricular hemorrhage (IVH) remains associated with high morbidity and mortality. Therapy with external ventricular drainage alone has not modified outcome in these patients. METHODS: Twelve pilot IVH patients who required external ventricular drainage were prospectively treated with intraventricular urokinase followed by the randomized, double-blinded allocation of 8 patients to either treatment or placebo. Observed 30-day mortality was compared with predicted 30-day mortality obtained by use of a previously validated method. RESULTS: Twenty patients were enrolled; admission Glasgow Coma Scale score in 11 patients was

A longitudinal study of patients with venous malformations: documentation of a negligible hemorrhage risk and benign natural history.

BACKGROUND: The natural history of cerebral venous malformations has not been well documented, and the clinical significance of these common lesions remains controversial. OBJECTIVE: The objective of this study was to follow longitudinally the clinical course of patients with cerebral venous malformations to document the natural history of the lesion. METHODS: Ninety-two patients with radiographically confirmed venous malformations were entered into the study between 1987 and 1996. Annual follow-up was maintained by clinic visits and/or phone interviews. Sixty-three patients (25 men and 38 women) with more than 1 year of follow-up were analyzed. McNemar's test and logistic regression analysis was applied to prevalence of presenting symptoms over time. An average per patient follow-up of 4.2 years yielded 2,721 retrospective and 301 prospective lesion-years for analysis. RESULTS: Average age at diagnosis was 39.1 years (SD, 18.7 years; range, 2 to 73 years). The most frequent lesion locations included the frontal lobe (55.6%, n=35) and the cerebellum (27%, n=17). The most frequent presentations included headache (50.8%, n=32), focal neurologic deficits (39.7%, n=25), and seizure (30.2%, n=19). Prevalence of headache (p=0.048) and seizure (p=0.016) decreased over time without treatment of the lesion. A second cerebrovascular lesion was identified in 12 patients (19%). Two patients had a symptomatic intracerebral hemorrhage attributable to their venous malformation. Risk of hemorrhage was 0.15% per lesion-year (95% CI, 0.06 to 0.38%). CONCLUSIONS: This study establishes that the natural history of venous malformations is benign, that the risk of hemorrhage from these lesions is negligible, and that conservative therapy is warranted.

Intraventricular hemorrhage in adults: complications and treatment.

Intraventricular hemorrhage (IVH) frequently occurs in the setting of intracerebral and subarachnoid hemorrhage, and is an independent and significant contributor to morbidity and mortality in both conditions. Present therapy of IVH is directed at treating the associated complications of obstructive and communicating hydrocephalus. These therapies are often inadequate to treat the complications and do not remedy the underlying IVH. Intraventricular thrombolysis is a promising but unproven new therapy that directly addresses the IVH and may reduce the incidence of obstructive and communicating hydrocephalus.

Thoracic outlet syndrome. Neurosurgical perspective.

Neurosurgeons have for the most part abdicated a role in thoracic outlet surgery and have left the diagnosis and treatment of these patients to thoracic, vascular, and general surgeons. We view this as unfortunate. Neurosurgeons are well-positioned to diagnose these conditions. The major source of confusion with regard to diagnosis is cervical spine disease or peripheral nerve entrapment diseases with which neurosurgeons are quite familiar. Orthopedic consultations with regard to shoulder pathology are encouraged. The supraclavicular approach to treatment is one with which most neurosurgeons will be comfortable. However, the transaxillary approach is also one which neurosurgeons should be able to master readily. Working with long instruments in deep holes is a familiar surgical environment. It should be stressed, however, that part of the reason for the controversy concerning TOS stems from the fact that the morbidity rate from the transaxillary approach is high in some centers. We believe this results from inadequate technique. Neurosurgeons with training that emphasizes a high regard for neural tissue should be able to master both approaches. Thoracic outlet syndrome is a disease that most neurosurgeons will see on a regular basis. Thus, it needs to be recognized, and patients need to be analyzed from a neurologic perspective. The differential diagnosis should be considered thoughtfully. Operative intervention by experienced surgeons in properly selected patients will yield satisfying results.