3D-Printer-Assisted Patient-Specific Polymethyl Methacrylate Cranioplasty: A Case Series of 16 Consecutive Patients

To develop a novel 3D-printer-assisted method to fabricate patient-specific implants for cranioplasty and to demonstrate its feasibility and its use in 16 consecutive cases.

We report on 16 consecutive patients who have undergone cranioplasty surgery for an extensive skull defect after decompressive surgery and in which the bone flap was not available. We present the workflow for the implant production using a 3D-printer-assisted molding technique. Preoperative, intraoperative, and postoperative data were analyzed/evaluated.

Eleven out of our 16 patients (68.7%) presented with extensive hemispheric bone defects. Indication for initial craniotomy were traumatic brain injury (4; 25%), acute subdural hematoma (4; 25%), ischemic stroke (3; 18.8%), tumor (3; 18.8%), and ruptured aneurysm (2; 12.5%). Median (range) operation time was 121 (89-206) minutes. Median (range) intraoperative blood loss was 300 (100-3300) mL. The mean (range) follow-up period is 6 (0-21) months. Complications occurred in 7 out of our 16 patients (43.8%), in 6 (37.5%) of which a reoperation was required to evacuate an extra-axial hematoma (3; 50%), for shunting of an epidural fluid collection (1; 16.7%), or for skin flap necrosis (1; 16.7%). One patient (16.7%) developed a chronic asymptomatic subdural fluid collection that was stable over the follow-up period.

Our workflow to intraoperatively produce patient-specific implants in a timely manner to cover cranial defects proved to be feasible. The results are cosmetically appealing, and postoperative CT scans show well-fitting implants. As implantable printable substrates are already available, we aim to advance and certify 3D-printed patient-specific implants in the near future.