Early experience with patient-specific low-cost 3D-printed polymethylmethacrylate cranioplasty implants in a lower-middle-income-country: Technical note and economic analysis

Abstract

Background: Polymethyl methacrylate (PMMA) cranioplasty, while widely prevalent, has limitations associated with freehand manual intraoperative molding. PMMA has been superseded by titanium or Polyetheretherketone implants, prefabricated commercially from preoperative CT scans, and boasting superior clinical and cosmetic outcomes. However, such services are extremely inaccessible and unaffordable in the lower-middle-income country (LMIC) settings. The study aims to describe, in detail, the process of making ultra-low-cost patient-specific PMMA cranioplasty implants with minimum resources using open-access software. We report the first such service from the public health-care system within Pakistan, a LMIC. Methods: Using open-source software, preoperative CT heads were used to prefabricate three-dimensional implants. Both implant and cranial defects were printed using polylactic acid (PLA) to assess the implant’s size and fit preoperatively. From the PLA implant, we fashioned a silicon mold that shapes the PMMA implant. Ten patients who underwent cranioplasty using our technique for various cranial defects with at least a 12-month follow-up were retrospectively reviewed. Clinical, cosmetic, and radiological outcomes were objectively assessed. Results: Etiology of injury was trauma (8), malignant MCA infarct (1), and arteriovenous fistula (1). We produced seven frontotemporal-parietal implants, one bifrontal, one frontal, and one frontoparietal. At 1 year, eight patients reported their cosmetic appearance comparable to before the defect. Radiological outcome was classified as “excellent” for eight patients. No postoperative complications were encountered, nor did any implant have to be removed. One patient’s implant involving the orbital ridge had an unsatisfactory cosmetic outcome and required revision surgery. The average cost per implant to the National Health Service was US$40. Conclusion: Prefabricated patient-specific PMMA cranioplasty implants are cost-effective. A single surgeon can fashion them in a limited resource setting and provide personalized medicine with excellent clinical/cosmetic-radiological results. Our method produces patient-specific cranioplasty implants in an otherwise unaffordable LMIC setting.