An open-label randomized multi-Centre study to evaluate anterior controllable Antedisplacement and fusion versus posterior Laminoplasty in patients with cervical ossification of the posterior longitudinal ligament: study design and analysis plan (STAR)

Abstract

Background: In treating patients with cervical ossification of the posterior longitudinal ligament (COPLL), a novel surgery technique - anterior controllable antedisplacement and fusion (ACAF) suggested promising clinical benefits in recent exploratory studies.

Methods: This is a multicentre, randomized, open-label, parallel-group, active controlled trial that will compare the clinical benefits of ACAF versus conventional posterior laminoplasty (LAMP) in severe COPLL patients. A total of 164 patients will be enrolled and randomized in a 1:1 ratio to either ACAF or LAMP group. The primary efficacy measure is cervical- Japanese Orthopaedic Association (C-JOA) recovery rate at 12 months post operation, which is to be derived by Hirabayashi's method from JOA data (range, 0 [worst] to 17 [normal condition]). Other important secondary efficacy endpoints include visual analogue scale (VAS) pain score (range, 0 [no pain] to 10 [most severe]), 10-item neck disability index (NDI, a total range of 0 to 50 points, the highest index the worst) and 6-level Nurick disability grade (range, 0 [mild] to 5 [severe]). Safety endpoints including adverse events, perioperative complications, and adverse events of special interest will also be assessed in this study. Full analysis set for baseline and efficacy data analyses according to the intention-to-treat principle will be established as the primary analysis population. Analysis of covariance (ANCOVA) will be used to analyze the C-JOA recovery rate, with random stratification factors (if appropriate) and the treatment group as fixed factors, and the baseline level of C-JOA score as covariate.

Discussion: This study is designed to demonstrate the clinical benefits of ACAF as compared to conventional LAMP in COPLL patients. It will provide clinical evidence that the novel surgery technique - ACAF might be more favorable in treating patients with severe cervical ossification of the posterior longitudinal ligament. (Words: 290).

Trial registration: ClinicalTrials.gov number, NCT04968028 .

Keywords: Anterior controllable antedisplacement and fusion; Cervical ossification of the posterior longitudinal ligament; Clinical outcome; Posterior laminoplasty; Randomized controlled trial.

Conflict of interest statement

None.

© 2021. The Author(s).

Figures

Fig. 1

Study flow chart. Abbreviations: ACAF, anterior controllable antedisplacement and fusion; C-JOA, cervical Japanese Orthopaedic Association; LAMP, posterior laminoplasty; NDI, neck disability index; VAS, visual analogue scale

Fig. 2

Schematic diagram of ACAF technique with steps A through E: (A) Expose and confirm surgical levels; (B) Remove discs, decompress at the levels cephalic and caudal to OPLL and remove the anterior portion of the middle vertebral bodies with OPLL; (C) Place interbody cages and create a groove on the left side, and fix anterior plate; (D) Create a groove on the right side, and isolate the vertebrae with OPLL and (E) Evaluate the vertebrae with OPLL. Sagittal (left) and transverse (right) sectional images of the cervical spine. Abbreviations: ACAF, anterior controllable antedisplacement and fusion; OPLL, ossification of the posterior longitudinal ligament