# Impact of PEEK implant surface design on postoperative complications in cranioplasty: a retrospective review

## TL;DR

This study compared smooth and perforated PEEK implants in cranioplasty and found no major differences in complications, but noted trends and a rare case of severe brain swelling with smooth implants.

## Contribution

The study reports the first documented case of malignant cerebral edema linked to smooth PEEK implants and highlights the potential impact of implant surface design on outcomes.

## Key findings

- No statistically significant differences in complication rates between smooth and perforated PEEK implants.
- Trends suggested higher wound complications and infections with smooth implants.
- A rare case of malignant cerebral edema was observed with smooth PEEK implants.

## Abstract

The aim of this study was to evaluate and compare complication rates and clinical outcomes associated with smooth and perforated polyetheretherketone (PEEK) implants used in cranioplasty.

A retrospective analysis of 94 patients who underwent cranioplasty with either smooth (n = 45) or perforated (n = 49) PEEK implants over a five-year period was conducted. Patient demographics, comorbidities, reasons for initial craniectomy, time interval between craniectomy and cranioplasty, postoperative complications, hospital stays, and rates of revision surgeries were analyzed. Multivariate logistic regression was used to control for confounding factors.

No statistically significant differences were observed in demographic characteristics, reasons for initial craniectomy, or median time to cranioplasty between groups. Complication rates including wound complications, infections, ventriculoperitoneal (VP) shunt placements, significant fluid collections, return to surgery, and implant removals were comparable between groups, though trends suggested potential increases in wound complications (17.8% vs. 8.2%, p = 0.11) and infections (17.8% vs. 8.2%, p = 0.22) in the smooth implant group. Interaction analysis indicated a significant reduction in significant fluid collections with smooth implants in trauma patients (p = 0.045). Importantly, a rare and previously unreported case of malignant cerebral edema following smooth PEEK implant placement was documented.

Although no statistically significant differences were found, the identified trends toward increased complications with smooth implants and the novel finding of malignant cerebral edema highlight the importance of implant surface characteristics. Further prospective randomized studies are needed to clarify these preliminary observations and guide clinical decision-making in cranioplasty procedures.

• PEEK cranioplasty implants are custom designed with either smooth or perforated surfaces, the choice of which is typically based on surgeon preference.

• No significant differences were found between smooth and perforated PEEK implants, but trends suggest higher rates of wound complications and infections with smooth implants.

• This study presents the first documented case of malignant cerebral edema associated with a smooth PEEK cranioplasty implant.

• Surface architecture of PEEK implants, particularly porosity and perforation, may impact osseointegration and clinical outcomes, highlighting an area ripe for future research.