Comparison of Assessment for Shunting with Infusion Studies Versus Extended Lumbar Drainage in Suspected Normal Pressure Hydrocephalus.

INTRODUCTION

Tools available for diagnosis of normal pressure hydrocephalus (NPH) and prediction of shunt-response are overnight ICP monitoring, infusion studies, and extended lumbar drainage (ELD). We investigated the shunt-response predictive value by infusion tests versus ELD.

MATERIAL AND

METHODS

We retrospectively recruited 83 patients who had undergone both infusion study and ELD assessments and compared infusion study hydrodynamics with improvement at clinic follow-up after ELD and after shunting.

RESULTS

62 patients had Rout >11 mmHg/mL/min. 28 Showed physiotherapy-documented improvement following ELD, and were selected for shunting, of which 21 were shunted. Of these, 19 showed improvement. Eight patients with Rout >20 mmHg/mL/min showed no response to ELD and were not shunted.There were 21 patients with Rout <11 mmHg/mL/min: five were shunted, showed improvement at follow-up, and had Rout >6 mmHg/mL/min. ICP amplitude did not differ at baseline or plateau between responders and non-responders.

CONCLUSIONS

ELD response and CSF dynamics differed remarkably. All patients with Rout <6 mmHg/mL/min showed no improvement with ELD, indicating that ELD and shunting might be contraindicated in these subjects. High Rout patients with no response to ELD could merit further consideration.