The spinal manometric examination (Queckenstedt's test). The effects of certain factors as seen in a hydraulic model.

Abstract

✓ Queckenstedt's dynamic manometry has been studied in a model constructed of clinical manometers, spinal needles, and commonly available items. Experiments with the model were made with the system unblocked, partially blocked, and totally blocked in ways to simulate clinical conditions. In clinical manometry what one observes is flow of fluid and its actual pressure. Poiseuille's law is predictive. Impedance to flow is governed by that segment of the system having the smallest cross section, whether it is the pathological block or the spinal needle chosen. If a blocking lesion contains fluid which the rising cerebrospinal fluid pressure can displace (as venous blood), a block may exist on myelography but not on manometry. When, in the presence of partial block, the manometer indication does not fall to the initial pressure but holds up at a new resting pressure, this new pressure probably represents the pressure of the lesion upon the cord and dura. When fluid cannot be displaced from a blocking lesion, as when it is totally solid, no amount of CSF pressure rise produced by jugular compression will overcome the block.