Research published Nov. 21 in the prestigious New England Journal of Medicine demonstrates a three-fold reduction in a risky repeat surgery for patients with subdural hematoma, a pooling of blood between the skull and the surface of the brain. The reduced risk was shown in patients whose hematoma was removed through traditional neurosurgery and who also underwent a less invasive procedure known as embolization to block the artery supplying blood to the hematoma.

The University of Oklahoma College of Medicine was one of 39 academic health institutions across the United States that enrolled patients in the EMBOLISE clinical trial. OU Health neurosurgeon Hakeem Shakir, M.D., an assistant professor of neurosurgery in the OU College of Medicine, led the study for OU. National trial leaders were Jason Davies, M.D., Ph.D., from the University of Buffalo and Jared Knopman, M.D., from Weill Cornell Medicine in New York City.

Subdural hematomas are most often caused by a head injury and can lead to headaches, confusion, vomiting and slurred speech because pooled blood is pushing on the brain. Severe hematomas require surgery in which the neurosurgeon either removes part of the skull to suction out the hematoma or drills holes and inserts tubes to drain the blood. While the surgeries are lifesaving and effective, subdural hematoma recurs in 8% to 20% of patients, necessitating a repeat surgery that often has poor outcomes and results in longer hospital stays, readmissions and higher costs.

To reduce the risk of repeat surgeries, the EMBOLISE trial studied the effectiveness of combining surgery with middle meningeal artery embolization, a nonsurgical procedure in which special tools pass through the blood vessels to block the artery sending blood to the hematoma. The 400 trial participants, ages 18 to 90, were randomly assigned to receive either surgery plus embolization (the treatment arm) or surgery alone (the control arm).

The study found that for every 100 patients, the combined approach of embolization and surgery reduced the risk of hematoma recurrence from about 11 patients to four.

“This study provides evidence for what we have believed in the neurosurgical and neuroendovascular community – that removing the hematoma surgically, followed by embolization, reduces the chance of a reoperation,” Shakir said. “It also showed that embolization is safe. We were seeking to change the paradigm of treatment, with particular benefit for an aging and elderly population. The study shows we have the opportunity to benefit even more patients than we had considered.”

The clinical trial was funded Medtronic, a medical device company whose Onyx Liquid Embolic System performed the embolization. The OU College of Medicine enrolled 20 patients in the trial.

“This study represents the importance of an academic health system and our tripartite mission of patient care, research and education,” Shakir said. “I’m afforded the opportunity to take care of patients while advancing modern medicine, and patients have access to cutting-edge technology and clinical trials.”

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About the Project

The study, “Adjunctive Middle Meningeal Artery Embolization for Subdural Hematoma,” can be found in the New England Journal of Medicine at https://www.nejm.org/doi/full/10.1056/NEJMoa2313472#ap0.