Diagnosing Pseudoarthrosis After Anterior Cervical Discectomy and Fusion

Abstract

Radiographic confirmation of fusion after anterior cervical discectomy and fusion (ACDF) surgery is a critical aspect of determining surgical success. However, there is a lack of established diagnostic radiographic parameters for pseudoarthrosis. The purpose of this study is to summarize the findings of previous studies, review the advantages and disadvantages of frequently employed diagnostic criteria, and present our recommended protocol of fusion assessment. This study identified randomized controlled trials, case-control studies, and prospective and retrospective cohort studies reporting on spinal fusion and how successful fusion after ACDF. Among the 39 articles reviewed, bridging bone across the operated levels on static radiographs was the most commonly used criteria to confirm fusion (31 of 39, 79%). Dynamic flexion-extension radiographs were used to assess for interspinous movement (ISM) (22 of 39, 56.4%) and change in Cobb angle (12 of 39, 30.8%). Computed tomography (CT) based findings (21 of 39, 53.8%) were employed in ambiguous cases with improved sensitivity and specificity. Reconstructed CT scans were used to assess for intragraft bridging bone and extragraft bridging bone (ExGBB). ExGBB were proved to have the highest diagnostic sensitivity and specificity for pseudoarthrosis detection when compared to all other radiographic criteria. The ISM <1 mm on dynamic flexion-extension radiographs had high diagnostic sensitivity and specificity as well. After our reviewing, we recommend using dynamic lateral flexion-extension cervical spine radiographs at 150% magnificationin which the interspinous motion <1 mm and superjacent interspinous motion ≥4 mm confirms fusion. In ambiguous cases, we recommend using reconstructed CT scans to evaluate for ExGBB.

Pseudarthrosis of the Cervical Spine

“…This provides confidence that adequate stress is placed on the arthrodesed segments to detect a fusion. Conversely, definitions of what constitutes a bony fusion have been no motion or <1–3 mm of movement on nonmagnified x-rays at the fused levels 18. While obtaining flexion-extension x-rays, it is important to instruct the patient to adequately flex and extend the neck to the point of maximal motion without pain or discomfort (Figs.…”

“…While obtaining flexion-extension x-rays, it is important to instruct the patient to adequately flex and extend the neck to the point of maximal motion without pain or discomfort (Figs. 1A, B). Cobb angle method —Using the change in Cobb angle method, previous authors have used definitions of 1.0, 1.5, 2.0, 4.0, and 5.0 degrees to assess change in Cobb angle from immediately postoperative to follow-up x-rays 18 Radiograph-based absence of trabecular bone —Static lateral x-rays are commonly used to assess for the absence of trabecular bone across the fused levels.…”

Mesenchymal Stem Cell Applications in Spine Disorders: A Comprehensive Review

“…This complication is developed by 1-2% of patients undergoing spine fusion [51], and these subjects often require revision surgery. Furthermore, MSCs may help improve fusion in stand-alone anterior cervical or lumbar implants [52]. Multiple studies have been conducted to prove that MSCs can induce spinal fusion in animal models [39], and hopefully they will lead the way for future clinical studies.…”

Cervical Intervertebral Cages: Past, Present, Innovations, and Future Trends with Review of the Literature.

“…In a prospective study, MSCT was statistically significant in correlation with intraoperative findings compared to dynamic radiographs. 30 Lin et al 117 in their review reported that no single method is perfect for the diagnosis of pseudoarthrosis and using dynamic lateral cervical films in 150% magnification. If the interspinous motion is <1 mm and superjacent interspinous motion is ≥4 mm, fusion is confirmed.…”