Asian Spine J.  2020 Feb;14(1):106-112. 10.31616/asj.2019.0024.

Incidences and Risk Factors for Postoperative Non-Union after Posterior Lumbar Interbody Fusion with Closed-Box Titanium Spacers

• Konomi T
• Yasuda A
• Fujiyoshi
• Yato Y
• Asazuma T

• KMID: 2501193
• DOI: http://doi.org/10.31616/asj.2019.0024

Abstract

Study Design: A retrospective, single-center clinical study with follow-up of more than 24 months. Purpose: To evaluate the union rates and relevant risk factors for non-union after posterior lumbar interbody fusion (PLIF) using porous-coated closed-box titanium spacers. Overview of Literature: Although the use of a closed-box interbody spacer for PLIF could avoid potential complications associated with the harvesting of autologous bone, few studies have reported detailed follow-up of fusion progression and risk factors for non-union in the early postoperative period.
Methods
PLIF using closed-box spacers without filling the autologous bone was performed in 78 (88 levels) consecutive patients. Surgical procedures included PLIF using traditional pedicle screw fixation (PLIF, n=37), PLIF using cortical bone trajectory screw fixation (CBT-PLIF, n=30), and transforaminal lumbar interbody fusion with traditional pedicle screw fixation (TLIF, n=11). Lateral dynamic radiography and computed tomography findings were investigated, and the relationship between the union status and variables that may be related to the risk of non-union was tested statistically.
Results
The overall bone union rates at 12 and 24 months were 68.0% and 88.5%, respectively. Incidences of bone cyst formation, subsidence, and retropulsion of spacers were 33.3%, 47.4%, and 14.1%, respectively. Union rates at 24 months were 94.6% in PLIF, 80.0% in CBT-PLIF, and 90.9% in TLIF. Multivariate logistic regression analyses showed that at 12 months postoperatively, the risk factor for non-union was age >75 years (p =0.02). In contrast, no significant risk factor was observed at 24 months.
Conclusions
These findings demonstrated the efficacy of interbody closed-box spacers for PLIF without the need to fill the spacer with autologous bone. However, the risk of non-union should be considered in elderly patients, especially intra-operatively and during the early postoperative stage.

Keyword

Posterior lumbar interbody fusion; Union rate; Radiographic assessment; Closed-box titanium spacer Copyright