Effect on Shunt Survival of the Biochemical and Cellular Properties of Cerebrospinal Fluid Among Patients Following Ventriculoperitoneal Shunting

Abstract

Study background: The burden of hydrocephalus in our region is huge. It is estimated that 6000 new cases are diagnosed in Kenya, most of which undergo ventriculoperitoneal shunting. These shunts frequently malfunction, with shunt blockage being the commonest cause of shunt failure. The biochemical and cellular properties of CSF are hypothesized to contribute to shunt blockage. This study aimed to demonstrate the impact of these CSF properties on shunt survival. Broad objective: To assess the biochemical and cellular properties of cerebrospinal fluid among patients undergoing ventriculoperitoneal shunting and their effect on shunt survival Study design and site: Prospective cohort study. This study was carried out in Kenyatta national hospital within the neurosurgical (ward 4C and the neurosurgical outpatient clinic), pediatric units (wards 3A, 3B, 3C and 3D)and the medical wards (wards 7A, 7B, 7D, 8A,8B and 8D). Participants and Methods: Patients were recruited into the study following VP shunt surgery for hydrocephalus. Data collected at recruitment included study identification, age, sex, residence and etiology of hydrocephalus. Additionally, data regarding the CSF biochemistry including proteins and glucose and cellularity was also abstracted from the patient files. Based on their baseline CSF biochemical and cellular properties, the patients were divided into two groups; those with normal and those with abnormal CSF biochemistry and cellularity. Patients were then be followed up in the neurosurgical clinics for a period of 3months during which shunt function was assessed clinically. Data management: This data was then entered to the statistical package for social sciences (IBM SPSS statistics 25.0) for data analysis. Descriptive statistics including means and medians, and proportions were run to establish characteristics of the study participants.For hypothesis testing, students’ T test of independence will be used for Continuous variables such as age and time to shunt failure (in days). Chi square was used for continuous variables. P values of <0.05 was considered statistically significant. Features significant in the univariate analysis will be advanced to a binary logistic regression model to assess for risk factors of shunt failure. Results of the regression model were reported in Odds ratios and corresponding 95% confidence intervals. Survival analysis using Kaplan Meir was used to assess for time to shunt failure. Categorical variables like marital status, gender, occupation is presented as proportions, bar charts, pie charts, and frequency tables while continuous variables was presented in histograms. xiii Expected main outcome measure: Shunt survival in days Results: During the study period, a total of 82 patients met the inclusion criteria and were recruited into the study. Forty-six (56.1%) were male while 36(43.9%) of them were female. The mean age was 15.5 months (SD 23.4 months). Majority (82.9%) of the patients had congenital hydrocephalus with Dandy walker malformation being the most common congenital anomaly seen. Most patients (52.44%) had normal CSF proteins while the remainder had elevated CSF proteins. Majority of the patients had reduced levels of CSF glucose at 65.9%. The CSF cell count was normal for most of the patients at 86.6%. Elevated CSF protein concentration was associated with an increased likelihood of ventriculoperitoneal shunt failure by 8.7 times compared to the patients with normal CSF protein concentration. Reduced CSF glucose concentration was associated was also found to increase the likelihood of shunt failure in this study. There was no correlation between the CSF cell count and the likelihood of shunt failure. Conclusion: Congenital anomalies were the commonest cause of hydrocephalus in this study. Almost half of the patients treated with hydrocephalus during the study period had elevated CSF proteins. Elevated CSF proteins increased the probability of shunt failure at 3 months of follow up. A positive correlation was also seen with reduced CSF glucose and the likelihood of shunt failure. CSF cell count did not affect shunt function in this study. Utility of the study: This study establishes evidence upon which the practice of shunt surgery in patients with abnormal CSF biochemical and cellular properties will be based on by showing the effects of this parameters on shunt survival. Key words: Hydrocephalus, CSF biochemistry and cellularity, ventriculoperitoneal shunt survival