Sagittal alignment and kinematics at instrumented and adjacent levels after total disc replacement in the cervical spine

• Published in: European spine journal Vol. 21; no. 8; pp. 1648 - 1659
• Main Authors: Barrey, Cédric, Champain, Sabina, Campana, Sophie, Ramadan, Aymen, Perrin, Gilles, Skalli, Wafa
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.08.2012; Springer Nature B.V
• Subjects: Adult; Aged; Arthroplasty; Biomechanical Phenomena - physiology; Cervical Vertebrae - diagnostic imaging; Cervical Vertebrae - physiology; Cervical Vertebrae - surgery; Computer programs; Female; Follow-Up Studies; Humans; Intervertebral discs; Kinematics; Male; Medicine; Medicine & Public Health; Middle Aged; Neck; Neurosurgery; Original; Original Article; Patient Satisfaction; Prospective Studies; Radiography; Range of Motion, Articular - physiology; Skull; software; Spine; spine (cervical); Surgical Orthopedics; Total Disc Replacement; Treatment Outcome; Biomechanics; Cervical disc prosthesis; Mobility; Artificial disc; Cervical spine; Kinematics
• ISSN: 0940-6719; 1432-0932; 1432-0932
• DOI: 10.1007/s00586-012-2180-8

Background The purpose of the study was to report radiological outcomes after total disc replacement (TDR) in the cervical spine through a 24 months follow-up (FU) prospective study with a special focus on sagittal alignment and kinematics at instrumented and adjacent levels. Materials and methods Thirty-two patients, who sustained one-level TDR with a ball-and-socket arthroplasty (Discocerv ™ implant, Scient’x/Alphatec Spine, USA) were consecutively included in the study. Clinical (visual analogical scale and neck disability index) and radiological parameters were measured preoperatively and postoperatively at 3/6 months, 1-year and 2-year FU. Sagittal alignment, ranges of motion (ROM) and center of rotations (CORs) were analyzed using specific motion analysis software (Spineview ™ , Paris, France). Patients CORs were compared with those of a control group of 39 normal and asymptomatic subjects. Results Both local and C3–C7 lordosis significantly increased postoperatively (+8° and +13° at 2 years, respectively). At instrumented level ROM in flexion–extension (FE) was measured to 10.2° preoperatively versus 7.5° at 1 year and 6.1° at 2 years. There were no differences in ROM at adjacent levels between pre and postoperative assessments. When compared with control group and preoperative measurements, we noted postoperative cranial shift of the COR at instrumented level for patients group. In contrast, there was no difference in CORs location at adjacent levels. Conclusion Through this prospective study, we observed that cervical lordosis consistently increased after TDR. In addition, although ball-and-socket arthroplasty did not fully restore native segmental kinematics with significant reduction of motion in FE and consistent cranial shift of the COR, no significant changes in terms of ROM and CORs were observed at adjacent levels.