Comparing Entry Sites for Cerebrospinal Fluid Shunts in Children with Hydrocephalus [Internet]

Excerpt

Background: Placement of a ventriculoperitoneal (VP) shunt for hydrocephalus is the most common procedure performed by pediatric neurosurgeons. Shunts are the mainstay of treatment for hydrocephalus, but they have a high failure rate; the initial shunt in a pediatric patient has a 30% to 40% failure rate within a year. Failures require admission to the hospital and repeat surgery, and they are associated with a small risk of death (1%-2%). Decreasing the risk of shunt failure is an important goal for patients and neurosurgeons. Neurosurgeons insert VP shunts into the brain's lateral ventricle at 1 of 2 entry sites on the head, anterior or posterior; the entry site is usually determined at the surgeon's discretion. There are conflicting reports in the literature about which entry site is best. However, the quality of the evidence in these reports is low, and more rigorous studies are needed to guide neurosurgeons and patients in this potentially important treatment decision.

Objectives: The primary objective of the trial was to compare entry sites on time to shunt failure. The study also attempted to determine if entry site affects patient quality of life (QOL) within 1 week of shunt insertion and at 1 year. Additionally, the trial compares other surgical parameters (eg, length of surgery) and complication rates.

Methods: We performed a parallel design randomized trial with an equal allocation of participants to anterior and posterior entry sites. Randomization was stratified by surgeon to help balance factors such as surgeon experience, skill, and hospital effects. All participants were children (<18 years old) with symptoms or signs of hydrocephalus and ventriculomegaly. Patients were excluded if they had a prior history of shunt insertion; however, a history of an external ventricular drain, a ventricular reservoir, a subgaleal shunt, or an endoscopic third ventriculostomy with or without choroid plexus coagulation was permitted. All participants received a simple VP shunt after randomization. The primary outcome was shunt failure. Shunt failure could be the result of any of 4 possible causes: obstruction, overdrainage, loculation, or infection. The criteria for these types of shunt failure were defined before the trial started and were based on clinical and radiographic findings; this definition has been used in previous studies. The trial was designed to detect a 10% or more absolute difference in the shunt failure rate at 1 year. Participants were not blinded to the surgical intervention, but an independent, blinded adjudication committee determined eligibility and primary outcome by reviewing data-collection forms, clinical notes, and imaging studies. All participants were followed for a minimum of 18 months to assess shunt function and complications. Kaplan-Meier curves for shunt survival were compared using the log-rank test, stratified by age (<6 months, ≥6 months), to determine significance for the primary outcome. The Pediatric Quality of Life Inventory (PedsQL) was administered preoperatively, within a week after surgery, and 1 year after surgery. Changes in the PedsQL score were assessed between groups. The study was conducted by the Hydrocephalus Clinical Research Network in partnership with the Hydrocephalus Association.

Results: The study randomized 467 participants at 14 tertiary care pediatric hospitals in North America from April 2015 to January 2019. The adjudication committee excluded 7 patients in each group for not meeting the study enrollment criteria. There were 229 patients in the posterior group and 224 in the anterior group for the primary analysis. The median age was 1.3 months; 60% of participants were boys. The majority of patients were White (63%), followed by Black (17%), and 19% were Hispanic or Latino. The most common etiologies of hydrocephalus were postintraventricular hemorrhage secondary to prematurity (32.7%), myelomeningocele (16.8%), and aqueductal stenosis (10.8%). At 1 year, the incidence of shunt failure was 25% (95% CI, 19.3%-30.7%) for an anterior entry site and 33% (95% CI, 26.9%-39.1%) for a posterior entry site. The average shunt survival time was 2.8 years (95% CI, 2.6-3.0) for the anterior group and 2.2 years (95% CI, 2.0-2.3) for the posterior group. There was no significant difference in the time to shunt failure (primary outcome) between entry sites (log-rank test, stratified by age <6 months and ≥6 months; P = .061). The hazard ratio (HR) for failure of a posterior shunt relative to an anterior shunt was calculated using a univariate Cox regression analysis and was nonsignificant (HR. 1.35; 95% CI, 0.98-1.85). One-week and 1-year QOL scores were not significantly different between the 2 surgical approaches. We also found no significant difference between entry sites for the duration of surgery, the number of attempts to place the ventricular catheter, ventricular catheter location, and length of stay. There were no significant differences between entry sites for intraoperative complications, postoperative cerebrospinal fluid leaks, pseudomeningoceles, shunt infections, skull fractures, postoperative seizures, new-onset epilepsy, or intracranial hemorrhages. The participating surgeons (n = 65) preferred an anterior entry site in most cases (72.8%). When a surgeon preferred an anterior entry site but performed a posterior entry site surgery, because of randomization, the risk of shunt failure increased (Cox regression model: HR. 1.49 [95% CI, 1.03-2.15]). We did not see this discrepancy when surgeons preferred a posterior entry site.

Conclusions: This randomized trial comparing posterior with anterior shunt entry site demonstrated no significant difference in the time to shunt failure. Anterior and posterior entry site surgeries have similar outcomes and similar complication rates. Both entry sites can be used for first-time shunt insertion in pediatric patients.

Limitations: The trial's QOL comparison is limited by a low rate of PedsQL surveys completed; fewer than 50% of participants completed the survey at all 3 time points (ie, preoperative, within 7 days of surgery, and at 1 year after surgery). There were fewer-than-expected shunt failure events over the course of the trial, which lowered statistical power to detect a difference between the entry sites, if one exists.