MULTIPLE SHUNT FAILURES - AN ANALYSIS OF RELEVANT FACTORS

Ventricular shunts that require multiple revisions are familiar to ped iatric neurosurgeons. We conducted a retrospective study to determine whether patients who require repeated shunt revisions represent a part icular cohort within shunted hydrocephalic children. The clinical reco rds of 244 children who had undergone shunt procedures between January 1990 and January 1996 were examined. They were divided into group 1: children with no shunt failure (n=136), group 2: children with one shu nt revision (n=52), group 3: children with 2 or 3 shunt revisions (n=3 4), and group 4: patients who had 4 or more shunt revisions (n=22). Pa tients in groups 3 and 4 accounted for 54.8% of the total of 531 shunt procedures. Etiology of hydrocephalus, nature of the dysfunction, CSF characteristics, and variables related to the surgical procedure were analyzed for each group. We observed a progressive shortening of the intervals between revisions as the numbers of surgeries increased, ind icating that shunts that tended to fail repeatedly did so sooner than those that did not. A Kaplan-Meier shunt survival curve showed that gr oup 2 had a slower rate of failure than either group 3 (chi(2)=7.13, P <0.01) or group 4 (chi(2)=4.76, P<0.05). The etiologies of the hydroce phalus were not randomly distributed among the four groups (chi(2)=81. 4, P < 0.001); there was a predominance of congenital conditions in gr oup 1. Repeated shunt revisions were associated with a progressive inc rease in the concentration of monocytes in the CSF (Kruskal-Wallis, P < 0.05). Our data suggest that multiple shunt revisions constitute a p henomenon that may be caused by specific, still unidentified, biologic al factors.