Definition of Overall Success. All of the following were required for a patient's outcome to be considered an Overall Success (Reprinted with permission from Gornet MF, Burkus JK, Shaffrey ME, Argires PJ, Nian H, Harrell FE: Cervical disc arthroplasty with PRESTIGE LP disc versus anterior cervical discectomy and fusion: a prospective, multicenter investigational device exemption study. J Neurosurg Spine. 2015 Jul 31:1-16. [Epub ahead of print] PMID: 26230424.22).
| Variables | Definition |
|---|---|
| Neck Disability Index (NDI) Success | ≥15-point improvement postoperatively compared to preoperative score |
| Neurological Status Success | Maintenance or improvement in postoperative neurological status (motor function, sensory function, and reflexes) compared to preoperative condition |
| Functional Spinal Unit (Disc Height) Success | Functional spinal unit anterior or posterior measurement height declined by no more than 2 mm vs. the 6-week postoperative assessment |
| No serious adverse event classified as implant or implant/surgical procedure associated | Serious AE = Grade 3 or Grade 4 per World Health Organization criteria (typically, resulting in ER visit or hospitalization) |
| No secondary surgical procedure classified as a “failure” | Supplemental fixation, removal or revision = treatment failure. Reoperation or other surgical procedure ≠ treatment failure |
AE = adverse event, ER = emergency room.