Effect of meningomyelocele closure on the intracranial pulse pressure.

Intracranial pressure (ICP) was monitored in a 12-year-old child before and after closure of a large, skin-covered meningomyelocele. Significant cerebrospinal fluid pulse pressure augmentation was observed over a spectrum of pressures following sac closure. Linear regression analysis was done to define pulse pressure-ICP relationships before and after surgery, and a significant increase in the regression slope was noted postoperatively. It is suggested that the unoperated meningomyelocele defect served as a shock absorber to dampen the intracranial pulse pressure. Meningomyelocele closure removes this shock absorber effect, resulting in pulse pressure augmentation.