Analysis of CSF Flow Through LP Shunt During Change of Posture

Abstract

Two methods for percutaneous study of lumboperitoneal (LP) shunt patency are described. The first is an LP shuntography in which patency of the shunt can be assessed by the intraperitoneal spread of contrast medium injected intrathecally via the lumbar route. This method was performed in 27 hydrocephalic patients. The other is a thermosensitive determination technique, in which patients. The other is a thermosensitive determination technique, in which patency of the shunt can be assessed by definite temperature changes. In a patient with an LP shunt, flow of CSF, and hence patency of the shunt, are indicated by a downward deflection of the recording trace. Twenty-three trials of the thermosensitive determination of CSF shunt patency in LP shunts of 19 hydrocephalic cases were performed. We got five different types of recording traces by the thermosensitive method. A flat-line recording (2 recordings) and an upward deflection (2 recordings) showed complete occlusion. Operative findings and LP shuntgraphy showed that four cases with a nearly flat line recording had a partial occlusion of the shunt. Patency of the shunt was comfirmed by LP shuntgraphy in all cases (12 recordings) with a gradual downward deflection. A steep downward deflection showed an acute excessive CSF drainage. An experimental study was carried out to perform a quantitative analysis of CSF flow in an LP shunt. Derived data suggested that the flow velocity was 10 ml/hr in a case with a nearly flat-line recordings, 30 ml/hr in a case with a gradual downward deflection and 60 ml/hr in a case with a steep downward deflection. An acute excessive CSF drainage which was suggested by a steep downward deflection and findings of LP shuntgraphy was shown to be dangerous.