gms | German Medical Science

Objective: Cranioplasty after decompressive craniectomy (DC) is not only neurologically an essential part of the follow-up therapy for trauma and stroke patients but also of great cosmetic importance. Both autologous and artificial implants often show unsatisfying cosmetic results especially in the temporal muscle region due temporal muscle atrophy or muscle resection during initial surgery. Mesh implants or bone cement are often used to intraoperatively reconstruct the temporal muscle defect but frequently lead to unsymmetrical visual results. Aim of this study was to directly integrate a temporal muscle reconstruction into the CAD/CAM cranial implant design to improve the cosmic results after cranioplasty.

Methods: A common procedure for designing a cranioplasty implant is to mirror the residual bone of the none decompressed contralateral skull. Our approach was to measure the distances from the intracranial midline to the outer skull and the outer border of the temporal muscle on the none-decompressed side in the axial view of the preoperative CT scans. The delta between skull and muscle border measurements were then added to the standard calculations (skull only) for the implant design thus leading to a thickening of the CAD/CAM implant in temporal muscle region. The above-mentioned measurements were then repeated in the postoperative scans to objectively analyze the cranial symmetry after cranioplasty. Cosmetic results were evaluated by an independent examiner and were also self- and relative-rated by use of a questionnaire. The results were categorized in 4 grades: very good, good, moderate or poor.

Results: A total of 15 patients (8 male and 7 female) underwent CAD/CAM cranioplasty with integrated temporal muscle reconstruction at our institute. 9 of the 15 patients had suffered from ischemic stroke and 6 patients from severe head trauma partially with multiple skull fractures prior to DC. After cranioplasty one Patient underwent revision surgery due to a postoperative epidural hematoma and one patient required a wound revision. No direct implant associated complications were detected. 13 (86.6%) of the 15 patients rated their cosmetic results as very good and 2 (13.3%) as good due to prominent scar tissue. Postoperative CT measurements revealed a high level of soft tissue symmetry of 93%.

Conclusion: Preoperative software based temporal muscle reconstruction for CAD/CAM cranial implants have shown to be a feasible method to improve the postoperative cosmetic results after cranioplasty. Surgical techniques and risks remain equal to those of standard CAD/CAM or autologous cranioplasty implying that this method is also safe. Further comparative analysis with standard cranioplasty will be conducted to solidify the cosmetic superiority of this methods.