CSF dynamics study in clinical practice: An evaluation of the bolus lumbar injection method

ABSTRACT

Cerebrospinal outflow resistance measurement [R[out]] is useful in the diagnosis, evaluation and monitoring of many disease states. The bolus lumbar injection method has been employed, using simple improvised bedside apparatus, to measure R[out] in various disease states affecting cerebrospinal fluid [CSF] dynamics, including normal pressure hydrocephalus [NPH], pseudotumour cerebri, post-meningitic and post-haemorrhagic hydrocephalus, using Marmarou's formula after establishing the R[out] values in normal population. In normal population, R[out] values ranged from 3.878-9.669 mm Hg/min/ml [mean 6.09 mmHg/min/ml]. Patients with normal pressure hydrocephalus, pseudotumour cerebri, and post-meningitic and post-haemorrhagic hydrocephalus had significantly higher R[out] values. The bolus lumbar injection method is a simple, fairly accurate, less expensive method for bedside measurement of CSF outflow resistance, which is affected in various disease states. R[out] values in normal Indian subjects is slightly lower than the other reported values for normal subjects. R[out] values correlated well with the outcome after shunt, in normal pressure hydrocephalus and other types of communicating hydrocephalus, and hence is a useful parameter for selection of patients for shunt surgery. It is also useful in establishing the diagnosis of pseudotumour cerebri