Anterior versus posterior entry site for ventriculoperitoneal shunt insertion: a randomized controlled trial by the Hydrocephalus Clinical Research Network
Authors: Whitehead William E. , Riva-Cambrin Jay , Wellons John C. , Kulkarni Abhaya V. , Limbrick David D. , Wall Vanessa L. , Rozzelle Curtis J. , Hankinson Todd C. , McDonald Patrick J. , Krieger Mark D. , Pollack Ian F. , Tamber Mandeep S. , Pindrik Jonathan , Hauptman Jason S. , Naftel Robert P. , Shannon Chevis N. , Chu Jason , Jackson Eric M. , Browd Samuel R. , Simon Tamara D. , Holubkov Richard , Reeder Ron W. , Jensen Hailey , Koschnitzky Jenna E. , Gross Paul , Drake James M. , Kestle John R. W. 
Published: November 2021

OBJECTIVE
The primary objective of this trial was to determine if shunt entry site affects the risk of shunt failure.

METHODS
The authors performed a parallel-design randomized controlled trial with an equal allocation of patients who received shunt placement via the anterior entry site and patients who received shunt placement via the posterior entry site. All patients were children with symptoms or signs of hydrocephalus and ventriculomegaly. Patients were ineligible if they had a prior history of shunt insertion. Patients received a ventriculoperitoneal shunt after randomization; randomization was stratified by surgeon. The primary outcome was shunt failure. The planned minimum follow-up was 18 months. The trial was designed to achieve high power to detect a 10% or greater absolute difference in the shunt failure rate at 1 year. An independent, blinded adjudication committee determined eligibility and the primary outcome. The study was conducted by the Hydrocephalus Clinical Research Network.

RESULTS
The study randomized 467 pediatric patients at 14 tertiary care pediatric hospitals in North America from April 2015 to January 2019. The adjudication committee, blinded to intervention, excluded 7 patients in each group for not meeting the study inclusion criteria. For the primary analysis, there were 229 patients in the posterior group and 224 patients in the anterior group. The median patient age was 1.3 months, and the most common etiologies of hydrocephalus were postintraventricular hemorrhage secondary to prematurity (32.7%), myelomeningocele (16.8%), and aqueductal stenosis (10.8%). There was no significant difference in the time to shunt failure between the entry sites (log-rank test, stratified by age < 6 months and ≥ 6 months; p = 0.061). The hazard ratio (HR) of a posterior shunt relative to an anterior shunt was calculated using a univariable Cox regression model and was nonsignificant (HR 1.35, 95% CI, 0.98–1.85; p = 0.062). No significant difference was found between entry sites for the surgery duration, number of ventricular catheter passes, ventricular catheter location, and hospital length of stay. There were no significant differences between entry sites for intraoperative complications, postoperative CSF leaks, pseudomeningoceles, shunt infections, skull fractures, postoperative seizures, new-onset epilepsy, or intracranial hemorrhages.

CONCLUSIONS
This randomized controlled trial comparing the anterior and posterior shunt entry sites has demonstrated no significant difference in the time to shunt failure. Anterior and posterior entry site surgeries were found to have similar outcomes and similar complication rates.