Not only is routine computed tomography (CT) to check for recurrence after evacuation surgery for chronic subdural hematoma unnecessary, but patients scanned on an as-needed basis experience better outcomes, a new perspective, randomized study suggests.

"We found no benefit of routine follow-up CT scans regarding good clinical outcome at 6 months. On the contrary, patients followed only clinically had fewer reoperations," Philippe Schucht, MD, Institute of Neurosurgery at Inselspital in Bern, Switzerland, said here during a late-breaking trial session at the 4th European Stroke Organisation Conference (ESOC) 2018.

The results of the investigator-initiated To Scan or Not to Scan: The Role of Follow-up CT Scanning for Management of Chronic Subdural Hematoma After Neurosurgical Evacuation (TOSCAN) trial suggest that ordering CT only as indicated by individual patient factors is a better strategy, Schucht said. It is also more cost-effective, he added.

Schucht and colleagues randomly assigned 181 patients in the immediate postoperative period to follow-up CT at day 2 and 1 month. Another 180 patients received no follow-up CT. The only exception was an emergency CT scan allowed for any study patient who showed new neurologic signs or symptoms.

Investigators defined a good outcome at 6 months as a modified Rankin Scale score of 0 to 3. The proportion achieving this outcome was 89% in the CT group and 93% in the no-CT group.

"There was no difference. Doing CT scans on this patient population did not influence the outcome," Schucht said. "Actually, we saw a bit of a shift to a better outcome if we did not check with a CT scan," Schucht said.

Similarly, none of the secondary outcomes differed significantly between groups at 6 months. These measures included National Institutes of Health Stroke Scale score and quality-of-life measures.

Reoperation, Morbidity Rates

The study did reveal a significant difference regarding the number of subsequent evacuation surgeries by 6 months. "We did more [secondary] operations in the CT arm — there was an increase of 50%.

And this increase in the number of operations was continuous and maintained over time," he said. Surgery for recurrent hematomas occurred in 59 patients in the CT group and 39 patients in the no-CT group (P = .055).

Length of stay was also significantly higher in the CT group.

Also, the rate of any morbidity or mortality was greater in the CT group, at 35% vs. 25% in the no-CT group. Twelve patients in the CT group and 8 patients in the no-CT group died (P = .5).

The investigators also found an "important increase of costs" associated with routine follow-up CT on a post hoc analysis. The cost of this practice averaged 3251 Swiss francs more.

Each Swiss franc is approximately the same value as a US dollar. The economic calculations include the costs of imaging, as well as the consequences of imaging more costs and more surgeries. "So altogether, there was an 18% higher cost in the CT arm," Schucht said.

"Therefore, performing follow-up CT scans only for new neurologic deficits appears as a cost-effective way to avoid unnecessary surgeries and to decrease morbidity and mortality," Schucht said.