Effect of Keeping Caspar Retractor During Prestige LP Cervical Disc Implantation on Intra- and Postoperative Outcomes

Implantation of the Prestige LP prosthesis requires substantial endplate modification and insertion forces, yet the manufacturer's guide recommends relaxing or completely removing the Caspar retractor before implantation, which we observed to cause vertebral instability during endplate preparation and prosthesis insertion. This study aimed to evaluate the effect of retaining the Caspar retractor during Prestige LP cervical disc implantation.

A total of 55 patients who underwent cervical disc arthroplasty (CDA) between January and December 2025 were retrospectively reviewed. The retractor group maintained the retractor during endplate preparation and prosthesis implantation, while the no-retractor group removed it after discectomy. Clinical outcomes and radiographic parameters were assessed preoperatively, intraoperatively, and at 1 week, 3 months, and 6 months postoperatively. Statistical analyses were performed using two-way repeated-measures ANOVA, paired and independent t-tests, Mann-Whitney U test, and Chi-square test.

Clinical outcomes were similar in both groups. The retractor group demonstrated superior intraoperative stability with reduced functional spinal unit (FSU) Cobb angle fluctuations (p = 0.001), fewer fluoroscopy exposures (p = 0.044), and shorter prosthesis implantation times (p = 0.017). The retractor group received significantly larger prostheses (p < 0.001). Postoperatively, the retractor group exhibited greater FSU height, disc height, and larger interfacet distance (all p < 0.005) but these differences diminished by 6 months. The retractor group also showed smaller bone-implant interface gap (p = 0.003) at 1 week, and more segmental range of motion (p < 0.008) and FSU height loss (p = 0.002) at 6 months. Subsidence and heterotopic ossification rates were comparable between groups.

During Prestige LP implantation in CDA, retaining the Caspar retractor enhanced intraoperative stability, improved prosthesis placement accuracy, and reduced fluoroscopy use, achieving comparable clinical outcomes. While associated with greater FSU height loss at 6 months, it did not increase complications, supporting its viability as a standard technical modification for Prestige LP implantation.