Background and Purpose: Increased transcranial Doppler velocities and regional cerebral perfusion defects have been well demonstrated in patients with subarachnoid hemorrhage, but the clinical significance of these changes has not been clearly defined, particularly in the presymptomatic stage of cerebral vasospasm. We have tested the hypothesis that a rapid, massive rise in Doppler velocity denotes progressive vasospasm by relating Doppler velocity increases to regional cerebral blood flow changes and to the subsequent clinical course.Methods: Serial transcranial Doppler sonography was performed in 121 patients; 20 of these patients were selected for blood flow mapping on the basis of rapid increases (>50 cm/sec/24 hr) in blood flow velocity. Cerebral blood flow was mapped by single-photon emission computed tomography using technetium-99m hexamethylpropyleneamine oxime.Results: Ten of IS patients studied before the onset of any deficit subsequently developed a focal neurological abnormality. In 14 of these 15 patients, and in a further five in which single-photon emission computed tomography was performed after the onset of a delayed neurological deficit, perfusion patterns were abnormal and correlated with sites of increased Doppler velocities. Four patients had zones of cerebral hypoperfusion but did not develop neurological deficitConclusions: Transcranial Doppler measurements can assist in identifying patients at risk of delayed ischemic deficit Selection of patients for regional cerebral blood flow mapping studies and for prophylactic anti-ischemic therapy may be considered on this basis. (Stroke 1992;23:674-679) KEYWORDS • cerebral blood flow • cerebral vasospasm • subarachnoid hemorrhage • ultrasonics

Angiography is always necessary in patients with penetrating stab wounds to the head, to exclude unexpected vascular lesions. The most important, since they are seldom clinically evident, are traumatic aneurysms and arteriovenous fistulae. It has previously been proposed that carotid angiography should be delayed until the start of the second week, to allow for better visualization of these complications. However, traumatic aneurysms can rupture at any time after the injury, and the mortality resulting from a second hemorrhage is unacceptably high. A prospective study was undertaken in which 330 patients with penetrating stab wounds to the head underwent angiography as soon as possible after admission. In 250 of these patients (76%), the weapon had already been removed by the assailant, and there was radiological evidence of penetration of the dura. Of these 250, 130 patients underwent angiography within 7 days of the injury. Another 51 patients, who presented late, underwent angiography more than 7 days after the injury. The timing of angiography did not affect the identification of traumatic aneurysms, the incidence of which was 12% in both groups. Of the patients with cranial stabs and who required urgent evacuation of intracerebral hematomas, 10% had traumatic aneurysms that could be dealt with simultaneously. No patient in this series suffered a secondary hemorrhage. We conclude that it is neither necessary nor safe to delay angiography. In some patients, either because of vasospasm or "cut-off" of a vessel, a second angiogram may be necessary to further elucidate a vascular abnormality that might not have been evident originally.

Previous studies in children have shown a strong correlation between raised intracranial pressure (RICP) and the Gosling pulsatility index (PI) as determined by transcranial Doppler ultrasonography (TCD). This diagnostic modality can, therefore, be used as a non-invasive method for the indirect evaluation of shunt function in children with hydrocephalus. Transcranial Doppler waveform analyses were done in 15 children with hydrocephalus, before and after insertion of a ventriculo-peritoneal shunt. All had clinical evidence of raised intracranial pressure (ICP) prior to surgery. CT had demonstrated dilated ventricles and, in some, additional features of RICP. Fifteen children without clinical and CT evidence of hydrocephalus were examined in an identical manner to act as a control group. The results clearly demonstrated that TCD may be a useful, non-invasive means of assessing the need for a cerebrospinal fluid (CSF) diversionary procedure and also for follow-up and monitoring.

Neurosurgical operations have traditionally been classified along the lines of general surgical procedures. A prospective study, during an 18-month period, was undertaken in 2249 patients undergoing neurosurgical procedures to establish and evaluate a method of classifying surgical cases by the use of specific neurosurgical criteria. Patients were placed in one of five categories according to the level and type of contamination at the time of surgery. Infection included all abnormal wounds and was documented as deep when infection occurred beneath the galea (subgaleal pus, osteitis, abscess/empyema, ventriculomeningitis) and as superficial if only the scalp (including wound erythema) was involved. A statistically significant difference in the sepsis rate was found in the different categories (P < 0.0001). Of the 342 "dirty cases," 9.1% of patients developed further wound sepsis. Concomitant cerebrospinal fluid fistulae (44%), second operations (11.8%), and patients with penetrating injuries (9.2%) were the major factors implicated in sepsis in the "contaminated" category (9.7%). In the "clean contaminated" category, a sepsis rate of 6.8% was found. Prolonged surgery (longer than 4 hours) was also implicated in higher infection rates (13.4%). This study strongly supports the separation of patients who have foreign materials implanted (sepsis rate = 6.0%) from "clean" patients, essentially cases categorized as having no known risk factors that may affect sepsis, in whom a sepsis rate of 0.8% was found (P < 0.001). Importantly, surgery for the repair of so-called "clean" neural tube defects in neonates requires separate consideration. An infection rate of 14.8% existed in this subgroup. A uniform system of reporting wound abnormalities is also proposed.