[Retraction pressure: a new parameter in intraoperative monitoring of neurosurgical patients].

The injurious effects of self-retained retractors on brain tissue during surgery were studied in patients with various neurosurgical diseases of the brain. The first part of the study was devoted to retraction pressure in neurosurgical patients. The highest values were observed in patients with abnormalities of the chiasmal-sellar area, median cranial fossa, and aneurysms of the anterior portions of Willis' circle. The second part was devoted to a retrospective analysis which revealed a high incidence of complications caused by the use of retractors in patients with tumors of the chiasmal-sellar area and median cranial fossa. In the third part we assessed the preventive effect of some methods aimed at reduction of the brain volume during surgery. Preliminary intravenous infusion of mannitol solution, puncture of the tumor cyst, ventricular and, possibly, lumbar draining were found to be prophylactically useful. Acute hyperventilation and intravenous preinjection of a saluretic were ineffective.