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Objective: Internal carotid artery (ICA) balloon test occlusions (BTOs) are performed in the angiography suite to predict whether the patient has adequate collateral circulation to prevent stroke when permanent ICA occlusion (PCO) is required for treatment. Although many criteria have been proposed to facilitate predictions of stroke risk after PCO, no BTO techniques have been subjected to predictive validity testing in outcome studies. We describe a prospective case series study that tests the predictive validity of quantitative cerebral blood flow (CBF) measurements during ICA BTO., Methods: Thirty-three patients with clinical indications for PCO underwent ICA BTO and then PCO. During BTO, standard neurological examinations, sustained-attention testing, and quantitative CBF measurements were performed. Two scalp scintillation detectors recorded washout data after ipsilateral intracarotid injection of xenon-133 through a port at the tip of the ICA-occluding balloon. Patients were monitored for the outcome measure of ipsilateral stroke for a mean of 34 months. The variables of quantitative CBF values, neurological examination results, sustained-attention test results, age, sex, and side of occlusion were examined with Kaplan-Meier log-rank tests, predictive validity analyses, and logistic regression analyses., Results: CBF of less than 30 ml/100 g/min during BTO was the only variable that predicted stroke after PCO (log rank = 5.87, P = 0.015). The negative and positive predictive values for CBF findings were superior to those for standard neurological examination findings and sustained-attention test results. Age, sex, and side of occlusion did not predict stroke., Conclusion: Quantitative CBF testing, via the intracarotid injection technique, during BTO seems to be an important predictor of stroke after PCO.

Objective: Ventricular shunts used to relieve hydrocephalus among patients with neurocysticercosis have been plagued by high shunt malfunction rates. We examined the characteristics of shunt malfunctions among patients with neurocysticercosis., Methods: This is a retrospective chart review of data for 122 patients who were admitted with a diagnosis of cysticercosis during a 5.5-year period. Cases of hydrocephalus requiring shunt placement were reviewed with respect to the segment of shunt obstruction, disease activity at the time of shunt placement, and the effects of antihelminthic treatment on shunt failures and longevity., Results: Twenty-one patients required 49 operations for relief of hydrocephalus, including 22 new shunt placements, 23 revisions, and 4 cyst extirpations. Of these shunt failures, 78% occurred within the first 12 months and 96% within 3 years. Of the failures that occurred in the distal segment, 75% occurred within 6 months. By comparison, 33% of proximal segment obstructions and 50% of the total number of valve obstructions occurred within the first 6 months. Of the shunts placed during the vesicular stage of infection, 63% required revisions, compared with 29% of those placed during the colloidal through calcified stages. Nineteen shunts were placed during the vesicular stage, and nine patients received a full course of antihelminthic treatment after shunt placement. In less than 6 months, 33% of the cases involving shunt placement followed by antihelminthic treatment exhibited shunt failure, compared with 90% of the cases without antihelminthic treatment (P < 0.05, chi(2) test)., Conclusion: Among patients with vesicular stage cysticercosis, placement of a ventriculoperitoneal shunt followed by a course of antihelminthic medication seems to promote shunt longevity.

Posterior atlantoaxial fusion is a common procedure performed for instability at C1-C2. This operation requires intact posterior elements of both the atlas and the axis. When this is not the case, the incorporation of the occiput and the lower spinal segments is usually required for adequate posterior fusion, but such a procedure limits the mobility of the upper cervical spine. A technique for the reconstruction of the posterior arch of the atlas with calvarial bone is described in this report. This technique allowed the successful fusion of the C1 and C2 vertebrae in a patient with traumatic atlantoaxial subluxation who also had a congenital absence of the posterior arch of the atlas.