Cerebral blood flow velocities after subarachnoid haemorrhage in relation to the amount of blood clots in the initial computed tomography.

In 72 patients with acute subarachnoid haemorrhage (SAH) the relationship between the amount of subarachnoid blood clots detected by initial cranial computed tomography (CCT) up to 48 hours after bleeding and the later development of vasospasm, established by blood flow velocity measurement with transcranial Doppler ultrasound (TCD) was investigated. The serial Doppler examinations started within the first 72 hours after SAH and were carried out every second day up to three weeks. Each Doppler recording was accompanied by a neurological examination. Patients classified as Hunt and Hess grade V were excluded from the study. All patients with remarkable brain oedema in CCT or with intracranial pressure above 25 mmHg were also excluded. Because of the well known age-dependence of vasospasm after SAH, two age groups were formed. A statistically significant correlation (p > 0.05) between blood flow velocities and blood load after SAH was not found. The mean age of the investigated 72 individuals was 48.9 years (14 up to 76 years). 47 patients were younger than 56 years. Linear regression analysis indicated a correlation with a quite low significance level (r = 0.350, p < 0.025) between TCD blood flow velocities and blood load in CCT in these younger subjects. No significant correlation (p > 0.05) between these two variables could be established in the 25 patients older than 55 years. In a second step an intra-individual comparison of side-to-side differences in TCD and CCT was made. There were no significant differences in blood flow velocities between subjects with or without side-to-side differences in cisternal blood load. It is concluded that the amount of blood visible on initial CCT after SAH is not a powerful predictor of cerebral blood flow velocities measured by TCD.

Stereotactically guided cavernous malformation surgery.

The incidence of a significant hemorrhage in the natural history of cavernomas is below 1% per year, but the risk of a second hemorrhage in patients with initial bleeding cavernomas is between 14% and 29%. In the light of these figures, all cavernomas ought to be resected if surgical-related morbidity can be minimized. Stereotactically guided neurosurgery offers the advantage of planning the least traumatic approach before craniotomy due to the knowledge of the exact localisation of the lesion. During a 2-year period 12 patients (age 16-54 years) with intracranial supratentorial cavernomas (size 0.5-1.8 cm) were treated by stereotactically guided microsurgery. The cavernomas were seated in a depth between 0.4 and 4.5 cm. 4 patients had an overt hemorrhage in their history. In six cases a seizure was the first symptom (altogether 8 patients had seizures preoperatively). Two patients were asymptomatic. Standard CRW (Cosman, Roberts, Wells) stereotactic system was used in all cases. The skin incision and the osteoplastic craniotomy (mean diameter 2.8 cm) were planned stereotactically. In 11 patients a transsulcal approach was used. The size of the corticotomy could be limited to less than 1 cm. Using the stereotactic method, all cavernomas were found with a high degree of accuracy. After lesionectomy a total of 1 to 2 mm of the surrounding yellow-stained brain tissue was sucked away because it contains hemosiderin and therefore iron, which may have an epileptogenic effect. No relevant surgical-related neurological morbidity was found in any patient a half year after surgery. Seven out of eight patients were free of seizures. One still had problems.

Pre- and intraoperative methods of controlling cerebral circulation in giant aneurysm surgery.

The surgical treatment of giant aneurysms usually requires temporary clipping of the aneurysmatic vessel. In planning the surgical approach and in applying temporary clips, the surgeon must consider collateral circulations. The functional integrity of the collateral vessels frequently decides the patient's outcome. In 8 patients with internal carotid artery giant aneurysm, measurements of blood flow velocities in the ipsilateral middle cerebral artery were performed preoperatively with transcranial Doppler ultrasound (TCD) during manual occlusion of the carotid artery at the neck. Three different perfusion patterns were established, and each collateral capacity was rated as insufficient, temporarily sufficient, or long-term unproblematic. Surgical strategies were conceived. In one patient with giant aneurysm of the middle cerebral artery the temporary occlusion test was not carried out preoperatively. Intraoperatively, collateral circulation was controlled using microvascular Doppler sonography (MVD). In 8 cases cortical blood flow (CoBF) was monitored by thermal diffusion flow probe and/or laser Doppler. In some cases, the complex pathological anatomy required a change in surgical strategy and a new MVD determination of collateral capacity. Despite these precautions 2 patients suffered ischemia of the basal ganglia and the white matter.