A NEW VENTRICULOPERITONEAL SHUNT WITH A TELEMETRIC INTRACRANIAL-PRESSURE SENSOR - CLINICAL-EXPERIENCE IN 94 PATIENTS WITH HYDROCEPHALUS

OBJECTlVE: We have developed a telemetric intracranial pressure sensor (OSAKA telesensor; Nagano Keiki Seisakusyo Co. Ltd., Tokyo, Japan) an d investigated the clinical usefulness of new ventriculoperitoneal shu nting with an OSAKA telesensor, an on-off valve, and a programmable va lve. METHODS: The OSAKA telesensor was applied in 94 patients at Osaka Medical College between March 1986 and December 1995. Postoperative m anagement, postoperative course, postural change of intracranial press ure (ICP), and zero drift of the OSAKA telesensor were investigated. R ESULTS: ICP was measured easily in all patients with no inconvenience. The setting of the programmable valve was adjusted postoperatively 38 times in 25 patients, Postoperative ICP in the upright position was - 14.9 +/- 4.5 mm Hg, and the difference in ICP between the supine and t he upright position was about 20 mm Hg. The slope of the decrease in I CP with continuous postural changes from the supine to the upright pos ition was steep until about 30 to 45 degrees but became incrementally less or even rose slightly above this angle. The initial slope was ste eper when the shunt was open than when the shunt was closed; it was al so steeper postoperatively than preoperatively. This initial slope, th erefore, may indicate the intracranial compliance, Seven cases of shun t malfunction were diagnosed correctly by ICP measurements. Zero drift of the OSAKA telesensor was easily corrected by comparing the ICP rea ding from the telesensor with the puncture pressure in the on-off valv e. CONCLUSION: The OSAKA telesensor is very useful in the postoperativ e care and pathophysiological evaluation of patients with hydrocephalu s.