Long-Term Radiographic and Functional Outcomes of Patients With Absence of Radiographic Union at 2 Years After Single-Level Anterior Cervical Discectomy and Fusion

Abstract

Study Design: Retrospective radiographic investigation. Objective: To evaluate the long-term radiographic and functional outcomes of patients in whom there is absence of radiographic union at 2 years after single-level anterior cervical discectomy and fusion (ACDF). Methods: Thirty-one patients were evaluated at standard postoperative time intervals per index trial protocol. Plain film radiographic fusion criteria at the arthrodesis level was defined as interspinous motion (ISM) <1 mm with corresponding motion at a non-arthrodesed superjacent level ISM ≥4 mm. Radiographs and functional outcome measures were acquired at each follow-up visit. Delayed union was defined as lack of radiographic union by 24 months. Results: Nine patients demonstrated radiographic evidence of delayed radiographic union at 24 months. Of those 9 patients, 5 patients demonstrated evidence of union during the follow-up period to 72 months. Despite the absence of radiographic union based on our criteria, 3 of the 4 remaining patients reported remarkable improvements in pain scores and functional outcomes. Conclusions: The natural history of delayed union at 24 months after ACDF was still favorable despite the prolonged delay in union. The majority of patients (5 of 9) without radiographic union at 24 months did proceed to radiographic union by final follow-up. In addition, patients that did not meet our criteria for fusion maintained postoperative improvements in patient-reported outcome scores. In summary, our study patients undergoing a single-level ACDF with asymptomatic radiographic delayed union at 24 months can expect maintained improvements in postoperative patient-reported outcomes scores and can still progress to successful radiographic fusion.

Diagnosis of spine pseudoarthrosis based on the biomechanical properties of bone

“…These data also support the observation that some pseudoarthrosis detected one year after ACDF will eventually heal. (72, 73) In addition, these data support the potential for delaying decisions regarding pseudoarthrosis treatment for at least 2 years, as the fusion process may continue to evolve for at least that long in some patients.…”

Preliminary 12-Month Safety and Efficacy Outcomes for the Treatment of Cervical Radiculopathy and Myelopathy with the Stalif-C Integrated Interbody Fusion Device

“…Lee and colleagues reported a 32.6% (29/83) pseudarthrosis rate after 1-3 level ACDF seen at 1 year postoperatively, but decreased to 9.6% (8/83) with 2 year radiographic follow up [33]. Lee and colleagues reported 9 delayed fusions at 2 years, noting 5/9 patients proceeded to union at 5 year follow up and 3 of 4 persistent nonunions continued to have excellent clinical results [34].…”

Current Management of Cervical Spondylotic Myelopathy

“…Multilevel ACDFs provide the benefit of improved cervical lordosis compared with single-level ACDFs. 41,42 A study by Bayerl et al 43 comparing single-level and multilevel ACDF reported a trend toward loss of lordotic correction at 5-year follow-up. No significance was noted in terms of clinical outcomes or postoperative complications.…”

“…Single-level ACDFs have shown superior results in terms of fusion rates, patient-reported outcomes, and relatively lower complications. Multilevel ACDFs provide the benefit of improved cervical lordosis compared with single-level ACDFs 41,42. A study by Bayerl et al43 comparing single-level and multi-level ACDF reported a trend toward loss of lordotic correction at 5-year follow-up.…”