Inguinal herniation with glial implants: possible complication of ventriculoperitoneal shunting.

The standard treatment of hydrocephalus is the insertion of a valve-regulated ventriculoperitoneal (VP) shunt, which may result in the development or clinical worsening of an inguinal hernia or hydrocele. A review of the British Columbia's Children's Hospital experience with VP shunt insertion (1983-1994) identified 304 patients who underwent VP shunt placement, 31 of whom subsequently required herniorrhaphy, 5 suffering recurrences. Two cases exhibited areas of glial differentiation (diffusely scattered in one sac from a bilateral repair, focally present in the second unilateral hernia repair) displaying cytoplasmic staining with glial fibrillary acidic protein and S100. At time of surgical repair of case 1 (bilateral hernia repair), the tip of the VP shunt was detected within the hernia sac exhibiting glial differentiation; no glial tissue was identified in the sac from the other side. We conclude that inguinal herniation is a common complication of VP shunt insertion, and the identification of glial tissue within such an inguinal hernia is a rarer complication, possibly occurring when the shunt tip lies in close proximity to the hernial mesothelial tissue.