Can Bilateral Partial Uncinatectomy Prevent Range of Motion Loss and Adjacent Segment Disease in Patients Treated with Cervical Disc Arthroplasty?

Abstract

In cases undergoing cervical disc arthroplasty (CDA), fusion formation and secondary adjacent segment disease (ASD) development has been reported primarily as cervical range of motion (ROM) loss due to paravertebral ossification. This research aimed to elucidate whether bilateral additional partial uncinatectomy (UT) preserved the motion for a more extended period to maintain the cervical ROM. The study investigated 122 cases who underwent CDA with bilateral additional partial UT at one of the C4-C5, C5-C6, and C6-C7 distances (Group A) and 154 cases who underwent CDA without additional partial UT (Group B). Flexion-extension (FE) ROM of C2-C7, surgical segment FE, lateral bending measurements, and the distance between spinous processes of the vertebrae forming the surgical segment were performed. The patients who developed ASD were determined. Clinical improvement in the groups was determined according to Odom's criteria. The presence of instability was investigated by examining the dynamic radiographs at the final follow-up. The final follow-up FE ROM and lateral bending of surgical segment measurements were significantly higher in Group A compared to Group B (P < 0.01 and P = 0.01, respectively). In addition, the number of cases with complete fusion in the surgical segment and ASD was higher in Group B compared to Group A (P < 0.01, P < 0.01, and P = 0.04, respectively). A similar clinical improvement was observed in both groups. No instability was found in the follow-up. Bilateral additional partial UT may delay the development of fusion without affecting stability in cases who underwent single-level CDA for C4-C5, C5-C6, and C6-C7 distances.