Cortical Bone Trajectory-Based Dynamic Stabilization

Abstract

Background: Cortical bone trajectory (CBT) screws have demonstrated similar biomechanical strength and fusion rates as conventional pedicle screws for short-segment lumbar fusion. However, very few studies have verified the viability of CBT screws in dynamic stabilization. In the present study, we compared the clinical outcomes of CBT-based Dynesys dynamic stabilization (CBT-DDS) with standard minimally invasive transforaminal lumbar interbody fusion (MI-TLIF).

Methods: Consecutive patients who had undergone CBT-DDS or MI-TLIF at L4-L5 or L3-L5 were retrospectively reviewed. All the radiological and clinical outcomes were compared between the 2 groups. The patient-reported outcomes included the visual analog scale scores for back and leg pain, Japanese Orthopaedic Association scores, and Oswestry disability index. The pre- and postoperative radiological evaluations were also reviewed.

Results: A total of 60 patients (20 patients in the CBT-DDS and 40 in the MI-TLIF groups) were analyzed. The MI-TLIF group had required a longer operation time (P = 0.010) than the CBT-DDS group but had had a similar estimated blood loss (P = 0.484). The perioperative complications, including screw loosening, wound infection, and radiculopathy, were similar in both groups (P > 0.05 for all). The degree of decreased range of motion after surgery was similar between the 2 groups (P = 0.781), and no pseudarthrosis developed in the MI-TLIF group.

Conclusions: Because the clinical and radiological outcomes of CBT-DDS were similar to those of MI-TLIF in patients with L4-L5 or L3-L5 spondylosis and spondylolisthesis, CBT-DDS appears to be a viable and effective alternative to MI-TLIF, with a shorter operation time and similarly limited segmental motility.

Keywords: Cortical bone trajectory; Dynamic stabilization; Minimally invasive surgery; Transforaminal lumbar interbody fusion.