What is the risk of a shunt malfunction after elective intradural surgery?

Object: Surgery for CSF diversion is the most common procedure performed by pediatric neurosurgeons. The failure rates for shunts remain frustratingly high, resulting in a burden to patients, families, providers, and healthcare systems. The goal of this study was to quantify the risk of a shunt malfunction in patients with an existing shunt who undergo an elective intradural operation.

Methods: All elective intradural surgeries (cranial and spinal) at Le Bonheur Children's Hospital from January 2010 through June 2014 were reviewed to identify those patients who had a functional ventricular shunt at the time of surgery. Patient records were reviewed to collect demographic, surgical, clinical, radiological, and pathologic data, including all details related to any subsequent shunt revision surgery. The primary outcome was all-cause shunt revision (i.e., malfunction or infection) within 90 days of elective intradural surgery.

Results: One hundred and fifty elective intradural surgeries were identified in 109 patients during the study period. There were 14 patients (12.8%, 13 male) who experienced 16 shunt malfunctions (10.7%) within 90 days of elective intradural surgery. These 14 patients underwent 13 craniotomies, 2 endoscopic fenestrations for loculated hydrocephalus, and 1 laminectomy for dorsal rhizotomy. Median time to failure was 9 days, with the shunts in half of our patients failing within 5 postoperative days. Those patients with failed shunts were younger (median 4.2 years [range 0.33-26 years] vs median 10 years [range 0.58-34 years]), had a shorter time interval from their previous shunt surgery (median 11 months [range 0-81 months] vs median 20 months [range 0-238 months]), and were more likely to have had intraventricular surgery (80.0% vs. 60.3%).

Conclusions: This is the first study to quantify the risk of a shunt malfunction after elective intradural surgery. The 90-day all-cause shunt failure rate (per procedure) was 10.7%, with half of the failures occurring within the first 5 postoperative days. Possible risk factors for shunt malfunction after elective intradural surgeries are intraventricular surgical approach, shorter time since last shunt-related surgery, and young age.