The Shunt Design Trial: Variation in Surgical Experience Did Not Influence Shunt Survival

Abstract

Introduction: An international multicenter randomized trial comparing standard pressure differential valves, Orbis Sigma valves and PS Medical Delta valves for children with newly diagnosed hydrocephalus failed to show a difference in the time to first shunt failure. Surgeons’ prior experience with the three valves varied. This analysis was performed to assess whether lack of surgical experience with any of the valves could explain the overall negative result. Methods: (1) Shunt survival was compared at high- and low-volume centers. (2) The 1-year shunt survival rates (±95% confidence interval) for patients entered in the first quarter and the last quarter of the 25-month accrual period were compared (for all patients, and for each shunt). Results: Survival curves for high- and low-volume centers were similar. Ninety of the 344 randomized patients were accrued in the first quarter and 93 in the last quarter. The 1-year shunt survival for all patients entered in the first quarter was 72% (±11%) compared to 64% (±10%) for patients entered in the last quarter. The shunt-specific results were 66% (±20%) compared to 54% (±20%) for Delta valve patients, 75% (±20%) compared to 70% (±17%) for standard valve patients and 76% (±18%) compared to 66% (±16%) for Orbis Sigma patients. Discussion: Shunt survival did not improve as surgeons accumulated experience over the course of the study. Although participating surgeons had varying levels of experience with the different shunts at the start of the trial, this does not appear to explain the overall negative trial result.

The Influence of Surgical Operative Experience on the Duration of First Ventriculoperitoneal Shunt Function and Infection

“…The clinical relevance of many of these factors has been reviewed by others [1, 4, 5, 6]. Surgeon-specific factors have received less attention [7, 8]. This study, based on a decade of experience in English-speaking Canada, demonstrates the importance of individual surgeon infection rates and experience on the duration of shunt function.…”

“…Evidence is strong for some illnesses and procedures [11, 12, 13, 14, 15, 16, 17, 18, 19, 20]and weak and non-existent for others [8, 21, 22, 23]. It is not clear whether outcomes depend on the experience of individual practitioners [22, 23]or the experience of a program or institution, and whether the experience is accumulated or is reflected by the current patient volume treated by a physician or institution.…”

“…While the outcomes did not differ significantly between high- and low-volume surgeons, the resource utilization was higher for patients with disease of comparable severity when treated by low-volume surgeons compared to high-volume providers [30]. The Shunt Design Trial compared the shunt survival of procedures performed by study surgeons and by trainees under their supervision [8]. In this selected and pre-qualified group of surgeons, no significant differences were found in the duration of shunt function based on who had done the procedure.…”

Lumboperitoneal Shunts in Children

“…In a recent multicenter trial, the infection rate in the hands of experienced pediatric neurosurgeons was 8% [20, 21, 22, 23]. The failure rate of VP shunts in children is likewise high, with about 50% of initial shunts still functioning after 2 years [20, 21, 22, 23]. Prospective data on the complication rates associated with LP shunts are difficult to find.…”

Duration of Antibiotic Therapy for the Treatment of Shunt Infection: A Surgeon and Patient Survey

“…Ventriculoperitoneal shunt infection remains an ever-present problem in the practice of pediatric neurosurgery despite much recent work on the topic [1, 2, 3, 4]. Although considerable research has addressed the prophylaxis of shunt infection, less attention has been paid to the management of these infections [5].…”