Radiological exploration on adjacent segments after total cervical disc replacement with Prodisc-C prosthesis

Area of Science:

• Spine surgery
• Cervical spine biomechanics
• Radiological assessment

Background:

• The long-term effects of total cervical disc replacement (TDR) on adjacent spinal segments remain incompletely understood.
• Understanding the relationship between cervical spine parameters and adjacent segment behavior post-TDR is crucial for patient outcomes.

Purpose of the Study:

• To analyze range of motion (ROM), lordosis (LOR), and intervertebral disc height (IDH) in upper and lower adjacent segments (UAS/LAS) before and after TDR.
• To identify factors influencing cervical spine radiological parameters in adjacent segments following TDR.

Main Methods:

• A 10-year retrospective study of patients who underwent TDR.
• Radiological parameters including UAS/LAS ROM, LOR, and IDH were primary outcomes.
• Secondary outcomes included C2-C7 ROM/LOR, surgical segment IDH, prosthesis migration, subsidence, heterotopic ossification (HO), and adjacent segment degeneration (ASD) assessed via X-ray.

Main Results:

• UAS-ROM and LAS-ROM remained stable post-TDR; LOR and IDH showed no significant pre- to post-operative changes.
• UAS-ROM and LAS-ROM were significantly larger in segments with adjacent segment degeneration (ASD).
• UAS-ROM correlated positively with C2-C7 ROM and LOR; UAS-LOR and LAS-LOR correlated with operated-segmental LOR and ROM, respectively.

Conclusions:

• Total cervical disc replacement has a limited effect on adjacent cervical spine segments.
• There is a significant interaction between upper and lower adjacent segments.
• Maintaining range of motion and intervertebral disc height in the operated segment is beneficial for adjacent segments.