Surface Modification of Cranioplasty Implants to Reduce Postoperative Cerebrospinal Fluid Collection: A Preliminary Clinical Study.

Objective: Postoperative cerebrospinal fluid (CSF) accumulation is a common complication after cranioplasty, causing wound tension, delayed healing, and infection. We developed a grid-patterned polyetheretherketone (PEEK) cranioplasty flap to enhance tissue integration and reduce dead space. In this single-center, nonrandomized pilot study, we evaluated the feasibility and safety of this approach as a preventive strategy against postoperative CSF collection. Methods: In this study, we prospectively included patients who underwent cranioplasty with patient-specific PEEK implants between March 2024 and October 2025. Patients who provided informed consent received a surface-modified PEEK flap with a grid-lattice pattern, whereas the others received a standard flap. We defined postoperative CSF collection as subgaleal fluid on examination or imaging evidence of a persistent space between the flap and scalp at 1 month and compared the outcomes and complications between the groups. Results: We included 36 patients in this study, of whom 20 and 16 belonged to the control and surface-modified groups, respectively. Median ages were 56.5 and 60.5 years, and the interval from craniectomy to cranioplasty(63.0 days) was shorter in the surface-modified group(103.0 days). In the control, 2 patients developed hemorrhages and 2 cases of CSF accumulation (10% each), whereas no CSF accumulation or other complications occurred in the surface-modified group. The group differences were not statistically significant, reflecting the small sample size. Conclusion: Grid-patterned surface modification of patient-specific PEEK flaps appeared feasible and safe, potentially helping prevent CSF collection after cranioplasty. These preliminary results are hypothesis-generating and warrant confirmation in larger controlled studies.