Abstract
BACKGROUND CONTEXT: Subsequent surgical procedures subject patients to additional risks and continue to be a driving factor for success rates and treatment cost-effectiveness. Previous results have shown TDR to produce lower rates of subsequent surgical intervention than ACDF within the 4-year window. Here, we present 5-year subsequent surgery rates of patients treated with one and two-level TDR and ACDF.
PURPOSE: To evaluate 5-year subsequent surgery rates of one and two-level TDR and SCDF patients.
STUDY DESIGN/SETTING: The study was conducted as part of a prospective, randomized, multicenter concurrently controlled clinical trial conducted across 24 sites in the US.
PATIENT SAMPLE: The patient population consisted of 575 randomized patients in a 2:1 ratio (1-level TDR: 1-level ACDF: 2-level TDT: 2-level ACDF). Twenty-five TDR training cases were also included in the analysis. For the 1-level arm, 179 patients were treated with TDR and 81 with ACDF. For the 2-level arm, 234 patients were treated with TDR and 105 with ACDF. Inclusion criteria included a diagnosis of symptomatic cervical degenerative disc disease at one or two levels with not history of previous operations on the cervical spine.
OUTCOME MEASURES: Patients undergoing subsequent surgery were further classified as having (1) index only, (2) index and adjacent or (3) adjacent-only level surgery. Subsequent surgeries that did not include a study failure such as hematoma evacuation and surgeries noncervical, adjacent levels (C7-T1) were included in the analysis.
METHODS: TDR patients were treated with Mobi-C© artificial disc (LDR Spine, USA). ACDFI patients were treated with allograft and anterior plate and screw instrumentation. Outcome measures were collected at baseline, 6 weeks, and at 3, 6, 12, 18, 24, 36, 46, and 60 months postoperatively.
RESULTS: AT 5 years, 4.47% of one-level TDR patients had subsequent surgery with 1.68% having an index only surgery. 1.12% having an adjacent and index surgery, and 1.68% having an adjacent only surgery. For one-level ACDF patients, 17.9% of patients had a subsequent surgery with a breakdown of 6.17% index only, 6.17% adjacent and index, and 4.94% adjacent only surgery patients. For the two-level treatment arm, 6.84% of TDR patients (4.70% index only, .043% adjacent and index, and 1.71% adjacent only), and 21.0% of ACDF patients (9.52% index only, 8.57% index and adjacent, and 2.85% adjacent only) had a subsequent surgical intervention. Differences between the total subsequent surgery rates of TDR abd ACDF patients were significant for both one-level (p=0.0008) and two-level (p=0.0002) treatment. When groups were analyzed based on surgery classification, no significant differences were observed in rate of index only or adjacent only surgeries for either cohort. However, one-level TDR patients did have a lower rate of surgeries involving both an adjacent and index level surgeries (p=0.032). Two-level TDR patients also showed a lower rate of subsequent surgeries performed at both and adjacent and index level (p=0.0002). Two TDR patients and 1 ACDF patient in the one-level treatment arm and 2 TDR patients and 3 ACDF patients in the two-level arm ultimately had more than one subsequent surgery. When analyzing causation for secondary surgeries, the one-level ACDF patients had a significantly higher rate of adjacent level indications (p=0.004) as did the two-level ACDF patients (p=0.004) when compared to TDR.
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