Comparing fourth ventricle shunt survival after placement via stereotactic transtentorial and suboccipital approaches.

OBJECT

Fourth ventricle hydrocephalus, or a "trapped" fourth ventricle, presents a treatment challenge in pediatric neurosurgery. Fourth ventricle hydrocephalus develops most commonly as a result of congenital anomalies, intraventricular hemorrhage, or infection. Standard management of loculated fourth ventricle hydrocephalus consists of fourth ventricle shunt placement via a suboccipital approach. An alternative approach is stereotactic-guided transtentorial fourth ventricle shunt placement via the nondominant superior parietal lobule. In this report, the authors compare shunt survival after placement via the suboccipital and stereotactic parietal transtentorial (SPT) approaches.

METHODS

A retrospective chart review was performed to find all patients with a fourth ventricle shunt placed between January 1, 1998, and December 31, 2011. Time to shunt failure was quantified as the number of days from shunt placement to first shunt revision or removal. Other variables studied included patient age and sex, origin of hydrocephalus, comorbidities, number of existing supratentorial catheters at the time of fourth ventricle shunt placement (as a proxy for complexity), operating surgeon, and number of previous shunt revisions. The crossover rate from one technique to the other after shunt failure from the original approach was also investigated.

RESULTS

In the 29 fourth ventricle shunts placed during the study period, 18 were placed via the suboccipital approach (62.1%) and 11 via the SPT approach (37.9%). There was a statistically significant difference in time to shunt failure, with the SPT shunts lasting an average of 901 days and suboccipital shunts lasting 122 days (p = 0.04). In addition, there was a significant difference in the rate of crossover from one technique to another, with 1 SPT shunt changed to a suboccipital shunt (5.6%) and 5 suboccipital shunts changed to SPT shunts (45.5%).

CONCLUSIONS

Fourth ventricle shunt placement using an SPT approach resulted in significantly longer shunt survival times and lower rates of revision than the traditional suboccipital approach, despite a higher rate of crossover from previously failed shunting procedures. Stereotactic parietal transtentorial shunt placement may be considered for patients with loculated fourth ventricle hydrocephalus, especially when shunt placement via the standard suboccipital approach fails. It is therefore reasonable to offer this procedure either as a first option for the treatment of fourth ventricle hydrocephalus or when the need for fourth ventricle shunt revision arises.