Laparoscopic surgery in children with ventriculoperitoneal shunts: effect of pneumoperitoneum on intracranial pressure--preliminary experience.

OBJECTIVES: We monitored changes in intracranial pressure (ICP) in 2 children with myelodysplasia undergoing laparoscopic bladder autoaugmentation. Both children had ventriculoperitoneal shunts (VPS) secondary to Arnold-Chiari malformations (type II).

METHODS: ICP was monitored through a 23-gauge needle placed into the shunt reservoir and connected to a pressure transducer and drainage system. Intraoperative mean arterial pressure, end-tidal CO2 (ETCO2), ICP, abdominal pressure, and cerebral perfusion pressures were all monitored.

RESULTS: Both children demonstrated rapid onset and sustained increases in ICP of greater than 12 mm Hg above baseline to a maximum pressure of 25 mm Hg. The average cerebrospinal fluid removed from each patient was 30 cc, thereby lowering ICP with no adverse neurologic sequela. The pCO2 remained constant throughout the procedures, as measured by ETCO2.

CONCLUSIONS: We believe that intracranial hypertension (IH) results from a "Valsalva-like" phenomenon, which causes cerebral vascular engorgement. In addition, the pneumoperitoneum may increase the resistance to outflow through the distal peritoneal catheter, causing a partial or complete shunt obstruction. Untreated IH may result in adverse neurologic sequelae from brain herniation in these children with hindbrain anomalies and potentially altered brain compliance. We believe it is prudent to perform intraoperative ICP monitoring in this subgroup of patients undergoing laparoscopic surgery and that IH should be treated by ventricular drainage.