Trabecular Bone Remodeling as a New Indicator of Osteointegration After Posterior Lumbar Interbody Fusion

Abstract

Study Design Retrospective cohort study. Objectives We newly found that trabecular bone remodeling (TBR) often appeared in the fixed adjacent vertebrae during bony fusion. Thus, TBR might indicate osteointegration. Hence, we aimed to investigate whether TBR in the early postoperative period could predict future bony fusion after posterior lumbar interbody fusion (PLIF). Methods We retrospectively analyzed 78 patients who underwent one-level PLIF. Demographic data were reviewed. Using computed tomography (CT) images taken at 3 months and 1 year postoperatively, we investigated the vertebral endplate cyst (VEC) formation, TBR in the vertebral body, cage subsidence, and clear zone around pedicle screw (CZPS). Results TBR had high interobserver reliability regardless of cage materials. VECs, TBR, and both were found in 30, 53, and 16 patients at 3 months postoperatively and in 30, 65, and 22 patients at 1 year postoperatively, respectively. The incidence of VEC, which indicates poor fixation, was lower in early (3 months postoperatively) TBR-positive patients, with a significant difference at 1 year postoperatively (3 months, P = .074; 1 year, P = .003). Furthermore, 3 (5.7%) of the 53 early TBR-positive patients had CZPS without instability at 1 year postoperatively. In 25 TBR-negative patients, 1 (4.0%) had pedicle screw cutout requiring reoperation, 1 (4.0%) had pseudarthrosis, and 4 (16%) had CZPS. Conclusions Patients with early TBR (3 months) did not experience pedicle screw cutout nor pseudarthrosis and had significantly fewer VECs than those without early TBR. Thus, TBR may be a new radiological marker of initial fixation after PLIF.

Reply to “Letter to the Editor Concerning ‘Trabecular Bone Remodeling as a New Indicator of Osteointegration After Posterior Lumbar Interbody Fusion.’ by Segi et al.”

“…We appreciate the insightful comments made by the authors of the letter regarding our article, “Trabecular Bone Remodeling as a New Indicator of Osteointegration After Posterior Lumbar Interbody Fusion.” 1 Thank you for taking the time to assess our manuscript and for the opportunity to respond to your comments.…”

Letter to the Editor Concerning “Trabecular Bone Remodeling as a New Indicator of Osteointegration after Posterior Lumbar Interbody Fusion.” by Segi et al.

“…We read with great interest the article by Segi et al 1 on the use of trabecular bone remodeling (TBR) as a new indicator of osteointegration after posterior lumbar interbody fusion. TBR is a promising clinical finding that can guide early stage bone fusion.…”