Comparison of outcomes in the management of abdominal pseudocyst in children with shunted hydrocephalus: a Hydrocephalus Clinical Research Network study
Authors: Ravindra Vijay M. , Jensen Hailey , Riva-Cambrin Jay , Wellons John C. , Limbrick David D. , Pindrik Jonathan , Jackson Eric M. , Pollack Ian F. , Hankinson Todd C. , Hauptman Jason S. , Tamber Mandeep S. , Kulkarni Abhaya V. , Rocque Brandon G. , Rozzelle Curtis , Whitehead William E. , Chu Jason , Krieger Mark D. , Simon Tamara D. , Reeder Ron , McDonald Patrick J. , Nunn Nichol , Kestle John R. W. , _ _ , _ _ , Kestle J. , Rozzelle C. , Rocque B. , Drake J. , Kulkarni A. , Whitehead W. , Browd S. , Hauptman J. , Pollack I. , Limbrick D. , Wellons J. , Naftel R. , Tamber M. , Riva-Cambrin J. , Jackson E. , Krieger M. , Chu J. , Simon T. , Hankinson T. , Pindrik J. , McDonald P. , Holubkov R. 
Published: June 2023

OBJECTIVE
Abdominal pseudocyst (APC) can cause distal site failure in children with ventriculoperitoneal shunts and is specifically designated as an infection in Hydrocephalus Clinical Research Network (HCRN) protocols. Specific management and outcomes of children with APCs have not been reported in a multicenter study. In this study, the authors investigated the management and outcomes of APC in children with shunted hydrocephalus who were treated at centers in the HCRN.

METHODS
The HCRN Registry was queried to identify children < 18 years old with shunts who were diagnosed with an APC (i.e., a loculated abdominal fluid collection containing the peritoneal catheter with abdominal distention and/or displacement of peritoneal contents). The primary outcome was shunt failure after APC treatment. The primary variable was reimplantation of the distal catheter after pseudocyst treatment back into the peritoneum versus implantation in a nonperitoneal site. Other risk factors for shunt failure after APC treatment and variability in APC management were investigated.

RESULTS
Among 141 children from 14 centers who underwent first-time management of an APC over a 14-year period, the median time from previous shunt surgery to APC diagnosis was 3.8 months. Overall, 17.7% of children had a positive culture: APC cultures were positive in 14.2% and CSF cultures in 15.6%. Six other children underwent shunt revision without removal; all underwent reoperation within 1 month. There was no difference in shunt survival (log-rank test, p = 0.42) or number of subsequent revisions within 6, 12, or 24 months for shunts reimplanted in the abdomen versus those implanted in a nonperitoneal location. Nonperitoneal implantation was associated with more noninfectious revisions (42.3% vs 22.9%, p = 0.019), whereas infection was more common after reimplantation in the abdomen (25.7% vs 7.0%, p = 0.003). Univariable analysis demonstrated that younger age at APC diagnosis (8.3 vs 12.2 years, p = 0.006) and prior shunt procedure within 12 weeks of APC diagnosis (59.5% vs 40.5%, p = 0.012) were associated with shunt failure after APC treatment. Multivariable modeling confirmed that prior shunt surgery within 12 weeks of APC diagnosis was independently associated with failure (HR 1.79 [95% CI 1.04–3.07], p = 0.035).

CONCLUSIONS
In the HCRN, APCs in the setting of CSF shunts are usually managed with externalization. Shunt surgery within 12 weeks of APC diagnosis was associated with risk of failure after APC treatment. Although no differences were found in overall shunt failure rate, noninfectious shunt revisions were more common in the nonperitoneal distal catheter sites, and infection was a more common reason for failure after reimplantation of the shunt in the abdomen.