Routine CT Not Warranted After Chronic Subdural Hematoma Surgery

Damian McNamara

May 24, 2018

GOTHENBURG, Sweden — 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 actually experience better outcomes, a new prospective, randomized study suggests.

"We found no benefit of routine follow-up CT scans in terms of 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 at 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 had no influence on outcome," Schucht said. "Actually, we saw a bit of a shift to better outcome if we did not check with a CT scan."

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 in terms of the number of subsequent evacuation surgeries by 6 months. "We did more [secondary] operations in the CT arm — there was an increase by 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.

In addition, 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."

Pros and Cons of Routine CT

Most people recover fully after evacuation surgery for chronic subdural hematoma, Schucht noted. However, there is a high recurrence rate, an average 20% to 30% and up to 40%, which "may be why most if not all surgical centers perform CT scans after surgery."

Proponents of routine CT in this patient population argue that such imaging allows for early detection and treatment, before clinical deterioration, as well as the ability to identify patients for closer neurologic surveillance. Skeptics argue that the predictive value of "any finding on follow-up CT for later symptomatic recurrence that has to be operated on anyway is very limited," Schucht said.

The two groups were balanced in terms of baseline characteristics. Each group was 66% female and had an average age of 73 years. The proportion receiving anticoagulation or antiplatelet treatment did not differ significantly.

"The study is very down-to-earth and clinically important," session co-moderator Christina Jern, MD, PhD, professor and chief physician at the Institute of Neuroscience and Physiology at the University of Gothenburg, Sweden, told Medscape Medical News when asked to comment.

"We don't want to waste money on things that don't improve the outcome — and also have side effects," Jern said. "They operated more frequently, and this didn't improve outcome."

"Obviously we should do the right things and not waste money," she added.

Schucht and Jern have disclosed no relevant financial relationships.

4th European Stroke Organisation Conference (ESOC) 2018. Presented May 18, 2018.

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