Hemicraniectomy for Malignant Middle Cerebral Artery Infarction (HeMMI): A Randomized Controlled Clinical Trial of Decompressive Hemicraniectomy with Standardized Medical Care Versus Standardized Medical Care Alone

Annabell E. Chua,1 Brian S. Buckley,2,3 Marie Carmela M. Lapitan,2,4 and
Roland Dominic G. Jamora1

1Department of Neurosciences, College of Medicine and
Philippine General Hospital, University of the Philippines Manila, Manila, Philippines
2Department of Surgery, College of Medicine and
Philippine General Hospital, University of the Philippines Manila
3National University of Ireland, Galway
4National Institutes of Health,
University of the Philippines Manila, Manila, Philippines

Background. Malignant middle cerebral artery (MCA) infarction, in which space occupying cerebral edema causes rapid neurological deterioration and transtentorial herniation, has a poort prognosis, with mortality rates as high as 80%. Decompressive hemicraniectomy can be performed in order to reduce increasing intracranial pressure and prevent herniation and further ischemic damage. Observational research has suggested that hemicraniectomy can reduce mortality and improve functional outcome, but only few small clinical trials have been conducted, so that the evidence base remains uncertain.

Methods. Single-center randomized controlled clinical trial comparing standardized medical care (SMC) alone versus SMC with decompressive hemicraniectomy (SMC+DH) in adults with malignant MCA infarction. Primary outcome: functional status at 6 months, with a modified Rankin Score (mRS) of > 4 considered a poor outcome. Secondary outcomes: mRS > 5, death.

Results. Follow-up was available for 24 of 29 recruited patients (82.76%; 13 SMC+DH, 11 SMC). No statistically significant differences in either functional status outcome or mortality were observed in either intention-to-treat or per-treatment analysis.

Conclusion. The HeMMI trial identified no statistically significant differnces betwen either treatment and functional outcomes or mortality. However, consideration of all previous trials suggests that decompressive hemicraniectomy is associated with increased chances of survival at 6 months, but also an increased likehood that survising patients will be serverly disabled. This should be explained carefully to patients or their legal guardians before treatment decisions are made.

Key Words: hemicraniectomy, decompressive surgery, malignant middle cerebral artery infarction