The Yield of Early Postoperative Computed Tomography after Ventriculoperitoneal Shunt Placement

Aim: Despite its wide distribution, VP shunt is a procedure frequently associated with complications and revision surgeries. Therefore, many neurosurgical centers routinely perform early postoperative cranial computer tomography (cCT). The aim of this study was to evaluate the yield of early routine postoperative cCT after VP-shunt placement for adult hydrocephalus.

Methods: We retrospectively reviewed 173 patients undergoing VP-shunt for diverse neurosurgical conditions. Radiological outcomes were proximal catheter malposition, comparison between ventricular width on pre- and postoperative imaging. Clinical outcomes included postoperative neurological outcome, revision surgery due to catheter malposition, revision surgery due to other causes, surgical, non-surgical and overall morbidity, and mortality.

Results: Only in 1.7% (n = 3) of the patients the early routine postoperative cCT led to a revision surgery by itself. The ratio for finding one asymptomatic patient with shunt malposition who eventually underwent revision surgery was 1:58. The ratios for finding one asymptomatic patients with a hygroma (1.2%) or a cranial bleed (0.6%) were 1:86 and 1:173, respectively. Five patients (2.9%) with a clinically asymptomatic shunt malposition or hygroma required an intervention based on the postoperative early cCT, leading to a ratio of 1:35. Not a single patient suffering from normal pressure hydrocephalus had shunt malposition, while in 40% of the patients with stroke the shunt was malpositioned. Lower preoperative EI was shown to be a statistically significant predictive factor for high grade shunt malposition.

Conclusion: Our results suggest that the yield of early routine postoperative cCT after frontal VP-shunt placement is rather low. Careful selection of the patients who might benefit, considering the underlying disease and preoperative radiological findings would reduce unnecessary costs and exposure to radiation.