Ventriculoperitoneal shunt survival in children who require additional abdominal surgery – are our estimations of the additional risk accurate?

Abstract

Objective. Ventriculoperitoneal shunt (VPS)-dependent children require abdominal surgery for many reasons. Our objective was to quantify the risk of abdominal surgery on VPS survival and to determine whether timing of abdominal intervention impacts on shunt outcome. Methods. Retrospective data collection was performed on all children undergoing primary VPS insertion or revision over 2 years (1/1/08–31/12/10). All shunt interventions were categorised into two groups: those undergoing additional “Abdominal surgery” (AS) versus those undergoing “Shunt-only” (SO). Kaplan–Meier survival curves were devised and analysed using log-rank. In the AS group, we compared shunt survival for shunts inserted at various “Time from abdominal surgery” (TAS). We conducted a control analysis to compare shunt survival in AS, SO and a control “clean general surgery” (SG) group. Chi-squared test was used to determine the cause of shunt failure in these three groups. Results. Three hundred and forty two shunts from 109 patients were included. Twenty patients contributed 118 shunts to the AS group. Median shunt survival was 3.68 months (95% CI = 1.01–6.47) and 22.6 months (95% CI = 8.76–36.4) in the AS and SO groups, respectively (log-rank = 16.6, p < 0.001). For each additional abdominal intervention, the risk of shunt failure increased by 55.4% (p < 0.001). Median shunt survival was 1.48 months (95% CI = 0.00–3.09, p < 0.001), if shunt insertion occurred within 1 year of abdominal surgery. Beyond 1 year, median shunt survival increased five-fold to 7.65 months (95% CI = 0.00–20.1, log-rank = 23.2, p < 0.001). There was a 29% reduction in risk of shunt failure per year interval between a shunt and an abdominal surgery (95% CI = 0.11–0.44, p < 0.005). Our control analysis confirmed that shunts in the AS group had worst survival and infection (p < 0.001). Conclusion. Additional abdominal surgery shortens VPS lifetime and increases risk of infection. Delaying abdominal surgery from a shunt intervention or vice versa by at least 1 year may prolong shunt survival.

Keywords::

• abdominal surgery
• hydrocephalus
• shunt infection
• ventriculoperitoneal shunt complications

Acknowledgements

We are grateful to all study participants for their contributions and to The University of Manchester for great technical support.

Declaration of Interest: We report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper. The authors alone are responsible for the content and writing of the paper.