Decompressive craniectomy (DC) is a surgical option in managing uncontrolled raised intracranial pressure refractory to medical therapy. The authors evaluate the addition of zygomatic arch (ZA) resection with standard DC and analyze the resulting increase in brain volume using three-dimensional volumetric CT scans. Measurements of brain expansion dimension morphometrics from CT images were also analyzed. Eighteen patients were selected and underwent DC with ZA resection. The pre- and post-operative CT images were analyzed for volume and dimensional changes. CT images of 29 patients previously operated on at the same center were retrieved from the picture archiving and communication system (PACS) and were similarly studied. The findings obtained from the two groups were compared and analyzed. Analysis from three-dimensional CT volumetric techniques revealed an significant increase of 27.97 ml (95% confidence interval [CI]: 39.98–180.36; p = 0.048) when compared with standard DC. Brain expansion analysis of maximum hemicraniectomy diameter revealed a mean difference of 0.82 cm (95% CI: 0.25–1.38; p = 0.006). Analysis of the ratio of maximum hemicraniectomy diameter to maximum anteroposterior diameter gave a mean difference of 0.04 (95% CI: 0.05–0.07; p = 0.026). The addition of ZA resection to standard DC may prove valuable in terms of absolute brain volume gain. This technique is comparable to other maneuvers used to provide maximum brain expansion in the immediate postoperative period.