Introduction:
Idiopathic normal pressure hydrocephalus (iNPH) is characterized by a typical clinical triad associating gait ataxia, cognitive decline and urinary incontinence, associated with normal cerebro-spinal fluid (CSF) pressure on lumbar puncture and enlarged cerebral ventricles. The lumbar puncture (LP) is the most frequently used preoperative procedure to drain CSF and to assess for symptoms improvement to decide if surgery is worthy. The tests, which are administered to identify symptoms changes before and after LP, are considered part of an "objective assessment". Due to the lack of sensitivity of the different objective tests, the consideration of subjective evaluations before and after LP seems to be relevant.
The main objective of this study is to evaluate if preoperative objective and subjective tests after LP are predictive for VP shunt efficacy in patients with iNPH, evaluated in terms of symptoms improvements, and to compare patient characteristics, complication rate, revision surgery and shunt outcome in subjective and objective LP responders who underwent a VP shunt.
Methods:
This is a monocentric retrospective observational study. All the patients with a diagnosis of iNPH and who underwent surgery for a VP shunt at the Lausanne University Hospital between January 2007 and December 2018 were considered for study inclusion and their data were collected. We separated our patient cohort with diagnosed iNPH according to their response to objective and subjective tests after LP. They were divided into group 1, which showed an improvement at objective assessments and group 2, which showed a subjective improvement.
Comparison between the subgroups were made using the “t test” according to the underlying distribution of the continuous variables. For categorical variables, the Chi-square test were used.
Results:
A total of 28 patients who underwent VP deviation surgery were included in this study. 11 of them were subjective responders and 17 were objective responders. There was no significant difference between the two groups characteristics except for the pre-LP BBS which was lower in the objective responders than the subjective responders. In addition, no statistically significant difference was found between the two groups in terms of complications and outcome after shunt. We also concluded that there was no correlation between the ventricular size reduction and the clinical improvement according to our results.
Conclusion:
There was no significant difference in the outcome and in complications between subjective and objective LP responders. Therefore, it would be appropriate to consider subjective assessments in addition to objective ones in order to improve the identification of shunt responders and the medical care of this disease.