ABSTRACT
BACKGROUND AND OBJECTIVES: Cranial reconstruction presents a significant challenge in cases involving pathologies with skull invasion, and various techniques have been used, including the intraoperative shaping of titanium mesh and the manual sculpting of bone cement serving as surrogates for the excised bone graft. In the context of prefabricated patient-specific implants (PSIs) for cranioplasty, precise surgical execution of craniotomies is paramount. This ensures optimal congruity between the implant and the defect created during the craniotomy, leading to a successful single-stage procedure encompassing both bone removal and reconstruction. This article presents a meticulous method for achieving such high-fidelity craniotomy and subsequent cranioplasty using PSIs in a single-stage surgery. METHODS: The procedure was implemented for 2 cases of meningiomas with osseous invasion. Through meticulous preoperative planning, the craniotomy template and implant were designed using computer-assisted design and manufactured on a 3-dimensional printer using the patient's computed tomography scans. Intraoperative fabrication of sterile polymethyl methacrylate replicas was achieved through the creation of silicone molds and subsequent injection molding techniques. Predesignated screw holes facilitated neuronavigation-assisted positioning of the template, aligning it accurately with the target site using registration points. Mini-screws firmly secured the template to the skull. Guided by the template, a craniotomy router performed the bone resection. On completion, the implant was affixed into place using plates and screws. RESULTS: This technique demonstrably facilitated a cost-effective, streamlined and precise application of prefabricated PSIs within a single-stage craniotomy-cranioplasty procedure. Subjective patient reports indicated high levels of satisfaction with the outcome. CONCLUSION: The template routed patient-specific implant 1-stage cranioplasty technique refines previous approaches through precise template localization on the skull, enabling an accurate craniotomy to match a prefabricated PSI. This single-stage procedure rivals hand-shaped methods in aesthetics and compares with the outcomes of 2-stage PSI cranioplasties. Additional studies are needed to validate our results.
ABSTRACT
BACKGROUND: Cranioplasty can be carried out using either fresh, frozen autologous bone or synthetic substitutes. Ordering artificial 3 dimensional (3D) implants is challenging and time consuming depending on geographical location. In this article, we share our experience using a streamlined process of producing 3D computer-assisted design (CAD) implants using commercially available 3D printers and silicone molds that can be easily replicated with consistent results and are associated with good outcomes. OBJECTIVE: To develop patient-specific implants for patients with cranial defects that are accurate, consistent, low cost, and easy to replicate while reducing operator-dependent factors. METHODS: We present data from 15 patients who underwent cranioplasty with 3D CAD-designed gentamicin-impregnated bone cement implants that were molded using the cold injection technique. RESULTS: The technique was consistent in result production, required little postdemolding manipulation, and showed no dimensional variation in design. Postoperative computed tomography scans showed excellent implant fit, and patients had a low complication rate. CONCLUSION: We have demonstrated a technique of mold preparation that is efficient and that produces a reliable result. Polymethyl methacrylate implants molded using this technique showed better reproducibility, higher accuracy, and precision than other types of implants and required minimal postdemolding clean-up.
