Recent clinical and experimental evidence has challenged the traditional concept of the venous system as a “passive” element in the genesis and evolution of intracranial vascular malformations. The authors review the clinical and experimental evidence linking the venous system and its anomalies to the genesis of various intracranial vascular malformations, including dural arteriovenous fistulas, cavernous malformations, parenchymal arteriovenous malformations, and capillary telangiectasia. They also describe the potential significance of different associations of these vascular anomalies.
Object The purpose of this study was to evaluate the incidence of seizures or epileptiform abnormalities on electroencephalography (EEG) studies in patients undergoing surgical treatment for acute subdural hematoma (SDH). Methods This was a retrospective study of 134 consecutive patients with acute or acute-on-chronic SDH who underwent surgical treatment at the authors' institution between January 2004 and July 2008. Detailed information was collected regarding baseline clinical data (including preexistent functional impairment); Glasgow Coma Scale (GCS) sum scores before and 24 hours after surgery; presence of clinical seizures; EEG findings; and functional outcome on discharge and up to the 6-month follow-up. All brain CT scans were reviewed to calculate SDH volume and midline shift. The Glasgow Outcome Scale (GOS) score was used for functional assessment, and GOS scores of 1–3 were considered indicative of poor outcome. Univariate and multivariate logistic regression analyses were performed to identify statistical associations. Results Clinical seizures or epileptiform changes on EEG were observed during the acute postoperative period in 33 patients (25%). Preexistent functional impairment and seizures/epileptiform EEG findings after surgery were independently associated with poor functional outcome upon hospital discharge (p < 0.001 for both). Preexistent functional impairment (p < 0.001), lower GCS score before surgery (p = 0.04), and lower GCS score 24 hours after surgery (p = 0.007), but not seizures/epileptiform EEG findings, were independently associated with poor functional recovery at 1- to 6-month follow-up evaluations. Seizures/epileptiform EEG findings had a strong association with lower GCS scores after surgery (p = 0.01), and they were more common in patients who underwent evacuation by craniotomy (p = 0.02). Conclusions Epileptic complications are common after acute SDH evacuation, and should be suspected in patients with an unanticipated depressed level of consciousness after surgery. Seizures worsen early functional outcome, but delayed favorable recovery is possible. Therefore, one should be cautious when discussing prognosis in the early postoperative period of patients with epileptic complications.
Clinical Reasoning: A 52-year-old man with spells of altered consciousness and severe headaches
Object The results of the International Subarachnoid Aneurysm Trial (ISAT) demonstrated lower rates of death and disability with endovascular treatment (coiling) than with open surgery (clipping) to secure the ruptured intracranial aneurysm. However, cost-effectiveness may not be favorable because of the greater need for follow-up cerebral angiograms and additional follow-up treatment with endovascular methods. In this study, the authors' goal was to compare the cost-effectiveness of endovascular and neurosurgical treatments in patients with ruptured intracranial aneurysms who were eligible to undergo either type of treatment. Methods Clinical data (age, sex, frequency of retreatment, and rebleeding) and quality of life values were obtained from the ISAT. Total cost included those associated with disability, hospitalization, retreatment, and rebleeding. Cost estimates were derived from the Premier Perspective Comparative Database, data from long-term care in stroke patients, and relevant literature. Incremental cost-effectiveness ratios (ICERs) were estimated during a 1-year period. Parametric bootstrapping was used to determine the uncertainty of the estimates. Results The median estimated costs of endovascular and neurosurgical treatments (in US dollars) were $45,493 (95th percentile range $44,693–$46,365) and $41,769 (95th percentile range $41,094–$42,518), respectively. The overall quality-adjusted life years (QALY) in the endovascular group was 0.69, and for the neurosurgical group it was 0.64. The cost per QALY in the endovascular group was $65,424 (95th percentile range $64,178–$66,772), and in the neurosurgical group it was $64,824 (95th percentile range $63,679–$66,086). The median estimated ICER at 1 year for endovascular treatment versus neurosurgical treatment was $72,872 (95th percentile range $50,344–$98,335) per QALY gained. Given that most postprocedure angiograms and additional treatments occurred in the 1st year and the 1-year disability status is unlikely to change in the future, ICER for endovascular treatment will progressively decrease over time. Conclusions Using outcome and economic data obtained in the US at 1 year after the procedure, endovascular treatment is more costly but is associated with better outcomes than the neurosurgical alternative among patients with ruptured intracranial aneurysms who are eligible to undergo either procedure. With accrual of additional years with a better outcome status, the ICER for endovascular coiling would be expected to progressively decrease and eventually reverse.
Conversion of external ventricular drains to ventriculoperitoneal shunts after aneurysmal subarachnoid hemorrhage: effects of site and protein/red blood cell counts on shunt infection and malfunction
Object The purpose of this study was to determine the incidence of shunt infection in patients with subarachnoid hemorrhage (SAH) after converting an external ventricular drain (EVD) to a ventriculoperitoneal (VP) shunt using the existing EVD site. The second purpose was to assess the risk of shunt malfunction after converting the EVD to a permanent shunt irrespective of the cerebrospinal fluid (CSF) protein and red blood cell (RBC) counts. Methods Data obtained in 80 consecutive adult patients (18 men and 62 women, mean age 60.8 years, range 33–85 years) who underwent direct conversion of an EVD to a VP shunt for post-SAH hydrocephalus between August 2002 and March 2007 were retrospectively reviewed. In each patient, the existing EVD site was used to pass the proximal shunt catheter. In no patient was VP shunt insertion delayed based on preoperative RBC or protein counts. Results The mean period of external ventricular drainage before VP shunt placement was 14.1 days (range 3–45 days). No patient suffered ventriculitis. The mean perioperative CSF protein level was 124 mg/dl (range 17–516 mg/dl). The mean and median perioperative RBC values in CSF were 14,203 RBCs/mm3 and 4600 RBCs/mm3 (range 119–290,000/mm3), respectively. No patient was lost to follow-up. The mean follow-up duration was 24 months (range 2–53 months). Three patients (3.8%) had shunt malfunction related to obstruction of the shunt system after 15 days, 2 months, and 18 months, respectively. There were no shunt-related infections. No patient suffered a clinically significant hemorrhage from ventricular catheter placement after VP shunt insertion. Conclusions In adult patients with aneurysmal SAH, conversion of an EVD to a VP shunt can be safely done using the same EVD site. In this defined patient population, protein and RBC counts in the CSF do not seem to affect shunt survival adversely. Thus, conversion of an EVD to VP shunt should not be delayed because of an elevated protein or RBC count.
Three-dimensional computed tomography angiography in presurgical planning for treatment of infratentorial dural arteriovenous fistulas
Dural arteriovenous fistulas (DAVFs) with pure leptomeningeal drainage may be cured by simple interruption of their venous side. This report illustrates the cases of 3 patients undergoing surgery for fistulas classified as Borden Type III, involving the posterior cranial fossa. Preoperatively, the surgical anatomy of these lesions was investigated with 3D reformatting of multislice CT angiography, in addition to conventional angiography. Reformatted images clarified the surgical anatomy of the malformation. Reconstructing both the osseous and the vascular structures and simulating the surgical orientation allowed localization of the dural takeoff point of the DAVF's drainage, showing its relationship with osseous landmarks. Precise localization of the DAVF's drainage may help in choosing the most direct and effective approach to treat the malformation. The reported cases could be treated with a standard retrosigmoid exposure, avoiding the need for more complex cranial base approaches.
Endovascular treatment of very small ruptured intracranial aneurysms