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Preoperative Radiographic Parameters to Predict a Higher Pseudarthrosis Rate After Anterior Cervical Discectomy and Fusion

Choi, Sung H. MD; Cho, Jae H. MD; Hwang, Chang J. PhD; Lee, Choon S. PhD; Gwak, Hyun W. MD; Lee, Dong-Ho MD, PhD

doi: 10.1097/BRS.0000000000002219
CERVICAL SPINE
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Study Design. Retrospective study.

Objective. To determine whether postoperative pseudarthrosis can be predicted from specific preoperative radiograph measurements.

Summary of Background Data. Various factors reportedly influence the occurrence of pseudarthrosis after anterior cervical discectomy and fusion (ACDF). However, to our knowledge, there are no reports on the relationships between preoperative radiographic parameters and pseudarthrosis.

Methods. We analyzed 84 consecutive patients (45 males, 39 females, mean age, 58.9 ± 11.2 yrs) who underwent ACDF. In all patients, allografts filled with local chip bone were inserted after discectomy and anterior plating was performed. On preoperative plain radiographs, we analyzed C2–C7 sagittal vertical axis, T1 sagittal slope, segmental motion, global cervical motion, and location of fusion segments. Pseudarthrosis was diagnosed as interspinous motion >1 mm with superjacent interspinous motion ≥4 mm on magnified dynamic lateral radiographs. Multivariate logistic regression was used to analyze the risk factors for pseudarthrosis and the receiver operating characteristic (ROC) curve was used to define a cutoff value.

Results. One hundred and twenty-five segments from 84 patients were included. The pseudarthrosis rate was 29% based on number of patients (24/84) and 20% based on number of segments (25/125). Multilevel surgery and segments at the lowest levels showed higher pseudarthrosis rates (P = 0.01). Per multivariate logistic regression analysis, greater preoperative segmental motion, greater preoperative T1 sagittal slope, and C6–7 segments were associated with a higher risk of pseudarthrosis (all P < 0.05). A segmental motion cutoff value of 12° demonstrated pseudarthrosis with sensitivity of 87%, specificity of 84%, and area under the curve of 0.899, indicating moderate accuracy.

Conclusion. Greater preoperative segmental motion, greater preoperative T1 sagittal slope, and lower fusion levels could be risk factors for pseudarthrosis following ACDF. Preoperative segmental motion >12° is likely to be an important indicator of the development of pseudarthrosis.

Level of Evidence: 3

Department of Orthopedic Surgery, Pusan National University Yangsan Hospital, Pusan National University School of Medicine, Busan, Korea

Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan, College of Medicine, Seoul, Korea.

Address correspondence and reprint requests to Dong-Ho Lee, MD, PhD, Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan, College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul, Korea, 05505; E-mail: osdlee@gmail.com

Received 9 January, 2017

Revised 9 March, 2017

Accepted 29 March, 2017

The manuscript submitted does not contain information about medical device(s)/drug(s).

No funds were received in support of this work.

Relevant financial activities outside the submitted work: board membership, consultancy, payment for lecture, grants, royalties, and stocks.

This study was presented at the 7th Annual Meeting of the Cervical Spine Research Society Asia Pacific Section in 2016 and the 44th Annual Meeting of the Cervical Spine Research Society in 2016.

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