Idiopathic normal pressure hydrocephalus (iNPH) and co-morbidity: an outcome analysis of 134 patients.
OBJECTIVE
The diagnosis and management of idiopathic normal-pressure hydrocephalus (iNPH) remains controversial, particularly in selecting patients for shunt insertion. Diagnostic criteria target the pathological features of the dynamics of the cerebrospinal fluid (CSF); however, the effectiveness in predicting the shunt success has room for improvement. The aim of our study was to systematically assess the influence of the co-morbidity determining the benefit from shunt surgery.


METHODS
Between 1997 and 2006 134 patients suffering from iNPH were treated with a ventriculo-peritoneal shunt with a gravity-controlled valve. The coincident disease processes were recorded. Shunt outcome was assessed at 2 years postsurgery in 116 patients (follow up rate 87%). The results of this follow-up examination (Kiefer score, NPH recovery rate) were compared using the preoperative co-morbidity index (CMI).


RESULTS
Of the 134 patients 76 (56.7%) had a CMI of 0-3 and 58 patients (43.3%) had a CMI of 4-8. Two years after surgery 65 out of 70 shunt responders (93%) could be identified in the patients group with a CMI of 0-3 and only 29 of 46 (63%) in group with a CMI of 4-8. This difference was significant (p < 0.0001). Remarkably few patients scoring between 6 and 8 on the CMI scale experienced a favourable outcome. The patients in this latter group showed excellent outcomes in only 1% and poor outcomes in 33%.


CONCLUSIONS
Data in this report affirm that co-morbidity is a statistically significant predictor of the quality of the clinical outcome for patients with iNPH undergoing shunt therapy. A CMI of more than 3 significantly decreases the chance of a favourable outcome and this should form part of the assessment when the risks and benefits of surgery are considered. According to these data, a successful outcome in patients with a CMI of 6 or more is not to be expected.
Department of Neurosurgery, Unfallkrankenhaus Berlin, Berlin, Germany. johannes.lemcke@ukb.de
Johannes
J
Lemcke
Ullrich
U
Meier
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002318:Cardiovascular Diseases / Q000145:classification / Q000453:epidemiology; D002557:Cerebrospinal Fluid Shunts / Q000379:methods; D005260:Female; D006801:Humans; D006850:Hydrocephalus, Normal Pressure / Q000453:epidemiology* / Q000503:physiopathology / Q000601:surgery*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009017:Morbidity; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D013997:Time Factors; D016896:Treatment Outcome