General Session: Cervical Motion Preservation

Presented by: J. McConnell - View Audio/Video Presentation (Members Only)

Author(s):

J. McConnell(1), J. Lindley(2), C. Tomaras(3), D. McKee(4), K. Baker(4)

(1) OAA Orthopaedic Specialists, Allentown, PA, United States
(2) Neurological Institute of Savannah, Savannah, GA, United States
(3) Polaris Spine and Neurosurgery Center, Atlanta, GA, United States
(4) Globus Medical, Inc., Audubon, PA, United States

Abstract

Purpose: Current cervical total disc replacements (CTDRs) incorporate articulating designs with various means of fixation and geometric configurations. Clinical studies suggest CTDR helps to improve painful symptoms and maintain motion at the impaired segment, reducing abnormal stress at adjacent segments, which may help prevent or delay adjacent segment degeneration (ASD). Range of motion (ROM) and the rate of adjacent level surgery were compared between a CTDR (SECURE®-C) and anterior cervical discectomy and fusion (ACDF).

Methods: A randomized, prospective, pivotal, IDE study of SECURE®-C was conducted at eighteen U.S. sites; data continued to be collected under a PAS. In the IDE, patients were randomized 1:1 to investigational SECURE®-C or control ACDF; each site performed five non-randomized training cases using SECURE®-C. Outcome measures and radiographic evaluations were collected pre-operatively and at 6 weeks, 3, 6, 12 and 24 months and annually thereafter through 84 months post-op. Radiographic outcomes and subsequent surgical intervention are reported. A total of 380 patients participated in the IDE. Data is presented for patients as-treated: 88 non-randomized and 148 randomized subjects received SECURE®-C (236 patients) and 144 received ACDF.

Results: Mean ROM during flexion-extension at the operated segment for SECURE®-C was 8.5° preoperative, 9.3° at 24 months and 9.1° at 84 months. Sagittal translation was 0.9mm preop, 1.2mm at 24 months and 1.1mm at 84 months. Mean adjacent level ROM (upper and lower adjacent levels) data is provided in Figure 1 for SECURE®-C and ACDF. The mean change in upper adjacent level motion was not statistically different for SECURE®-C and ACDF at 24 through 84 months (0.025< pp< 0.975). The mean change in lower adjacent level motion was statistically lower for SECURE®-C at 24, 60 and 72 months (pp≤0.025) and was not statistically different at all other time points (0.025< pp< 0.975). At the last 84 month follow-up, 4.2% (10/236) of SECURE®-C patients underwent adjacent level surgery compared to 17.4% (25/144) of ACDF patients. Of the 10 SECURE®-C patients who underwent surgical treatment at an adjacent level, six patients had surgery at one or two lower adjacent levels and four underwent surgery at one or two upper adjacent levels. Of the 25 ACDF patients having adjacent level

Surgery: eight had upper adjacent level surgery, four had two upper adjacent levels treated, six experienced upper and lower level surgery, six had lower levels treated, and one patient underwent surgery at an unknown adjacent level.

Conclusions: The rate of adjacent level surgery among patients treated with SECURE®-C was four times less than that of patients treated with ACDF. Motion was maintained at the operated level with an average ROM of 9.1° at 84 months postoperatively compared with 8.5° preoperatively. The selectively constrained design of SECURE®-C allows for maintenance of motion at the operated and adjacent levels through 84 months.

Mean ROM at Adjacent Levels