Shunt survival after failed endoscopic treatment of hydrocephalus
Authors: Warf Benjamin C. , Bhai Salman , Kulkarni Abhaya V. , Mugamba John 
Published: October 2012

Object
It is not known whether previous endoscopic third ventriculostomy (ETV) affects the risk of shunt failure. Different epochs of hydrocephalus treatment at the CURE Children's Hospital of Uganda (CCHU)—initially placing CSF shunts in all patients, then attempting ETV in all patients, and finally attempting ETV combined with choroid plexus cauterization (CPC) in all patients—provided the opportunity to assess whether prior endoscopic surgery affected shunt survival.

Methods
With appropriate institutional approvals, the authors reviewed the CCHU clinical database to identify 2329 patients treated for hydrocephalus from December 2000 to May 2007. Initial ventriculoperitoneal (VP) shunt placement was performed in 900 patients under one of three circumstances: 1) primary nonselective VP shunt placement with no endoscopy (255 patients); 2) VP shunt placement at the time of abandoned ETV attempt (with or without CPC) (370 patients); 3) VP shunt placement subsequent to a completed but failed ETV (with or without CPC) (275 patients). We analyzed time to shunt failure using the Kaplan-Meier method to construct survival curves, Cox proportional hazards regression modeling, and risk-adjusted analyses to account for possible confounding differences among these groups.

Results
Shunt failure occurred in 299 patients, and the mean duration of follow-up for the remaining 601 was 28.7 months (median 18.8, interquartile range 4.1–46.3). There was no significant difference in operative mortality (p = 0.07 by log-rank and p = 0.14 by Cox regression adjusted for age and hydrocephalus etiology) or shunt infection (p = 0.94, log-rank) among the 3 groups. There was no difference in shunt survival between patients treated with primary shunt placement and those who underwent shunt placement at the time of an abandoned ETV attempt (adjusted hazard ratio [HR] 1.14, 95% CI 0.86–1.51, p = 0.35).
Those who underwent shunt placement after a completed but failed ETV (with or without CPC) had a lower risk of shunt failure (p = 0.008, log-rank), with a hazard ratio (adjusted for age at shunting and etiology) of 0.72 (95% CI 0.53–0.98), p = 0.03, compared with those who underwent primary shunt placement without endoscopy; but this was observed only in patients with postinfectious hydrocephalus (PIH) (adjusted HR 0.55, 95% CI 0.36–0.85, p = 0.007), and no effect was apparent for hydrocephalus of noninfectious etiologies (adjusted HR 0.98, 95% CI 0.64–1.50, p = 0.92). Improved shunt survival after failed ETV in the PIH group may be an artifact of selection arising from the inherent heterogeneity of ventricular damage within that group, or a consequence of the timing of shunt placement. The anticipated benefit of CPC in preventing future ventricular catheter obstruction was not observed.

Conclusions
A paradigm for infant hydrocephalus involving intention to treat by ETV with or without CPC had no adverse effect on mortality or on subsequent shunt survival or infection risk. This study failed to demonstrate a positive effect of prior ETV or CPC on shunt survival.