External decompressive craniectomy including resection of temporal muscle and fascia in malignant hemispheric infarction.

Decompressive craniectomy procedures are used for malignant hemispheric infarctions. However, the temporal muscle and fascia are significant limiting factors for external herniation of an edematous brain. Therefore, the authors performed a decompressive craniectomy and expansive duraplasty combined with resection of the temporal muscle and fascia for 15 patients with a malignant hemispheric infarction. The volume of the maximum external herniation that was measured on the basis of a CT volumetry study ranged from 130 to 300 ml (mean +/- standard deviation, 200 +/- 64 ml) on postoperative Day 3.2 +/- 1.5 (range 2-5 days postoperatively). The mean value represented a 2-fold volume expansion in comparison with the conventional decompressive craniectomy, and the greater the external herniation obtained by external decompression, the smaller the midline brain shift after surgery. The mortality rate, favorable outcomes (modified Rankin Scale Scores 1-3), and unfavorable outcomes were 20, 60, and 20%, respectively, and the masticatory function was only minimally affected. Furthermore, a cranioplasty involving reconstruction of the temporal muscle defect performed using a MEDPOR implant resulted in good cosmetic outcomes with no temporal hollow. Resection of the temporal muscle in a decompressive craniectomy was shown to provide greater decompression and better clinical outcomes for malignant hemispheric infarctions at an acceptable cost of minimal masticatory dysfunction and cosmetic disfigurement.