Search Results

You are looking at 1 - 3 of 3 items for

  • Author or Editor: Helge Nornes x
  • By Author: Grip, Arne x
Clear All Modify Search
Restricted access

Helge Nornes and Arne Grip

✓ Local hemodynamics were studied in 16 patients undergoing total extirpation of cerebral arteriovenous malformation (AVM). Directional Doppler technique was used for the registration of blood velocities in vessels feeding and draining the AVM. Calculated flow in single feeding arteries ranged from 3 to 550 ml/min (average, 180 ml/min). An estimation of total AVM flow was possible in nine patients, and ranged from 150 to more than 900 ml/min (average, 490 ml/min). Pressure recordings were made from feeding arteries at their entrance to the AVM. This pressure was well below the systemic arterial blood pressure in all cases, and ranged from 40 to 77 mm Hg (average, 56 mm Hg). On temporary occlusion, this stump pressure instantly rose to from 55 to 95 mm Hg (average, 76 mm Hg). Draining vein pressure before occlusion ranged from 8 to 23 mm Hg (average, 15 mm Hg), and fell to zero in all patients when the AVM was occluded. These data and other clinical observations are discussed with regard to adjacent brain-tissue perfusion, and with special emphasis on the circulatory breakthrough that can follow the occlusion of these high-capacity shunts.

Restricted access

Helge Nornes, Arne Grip and Per Wikeby

✓ The use of a pulsed echo Doppler technique during procedures for occlusion of intracranial aneurysms is described. Saccular aneurysms can be located with reference to probe position and depth setting. Tracings of intra-aneurysmal flow are presented, and the characteristic flow pattern is discussed. Special emphasis has been placed on the parent artery flow, particularly the effect of lumen reduction on flow velocity. Results of flow velocity studies on the cognate (direct) and collateral flow in the middle cerebral artery and the proximal anterior cerebral artery are presented and discussed.

Restricted access

Helge Nornes, Arne Grip and Per Wikeby

✓ The use of a pulsed echo Doppler technique during surgery for cerebral arteriovenous malformation is described. The equipment and the methods employed are presented. The main advantages are easy determination of flow direction and pattern of the vasculature involved, allowing a precise discrimination between inflow and outflow channels. Deep-seated malformations, not visible at the brain surface, can be located with the Doppler technique. The ultrasound probe was placed on the brain surface with a slight pressure on the intact pia mater. The precise direction and depth of the malformation could be determined in relation to the recording site. This facilitated the planning of cortical incisions, identification of vessels involved, and the vascular procedure to be employed.