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.

Objective:

To compare 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 received CBT-DDS or MI-TLIF at L4-5 or L3-4-5 were retrospectively reviewed. All the radiological and clinical outcomes were compared between the two groups. The patient-reported outcomes (PRO) included visual analog scales of back and leg pain, Japanese Orthopaedic Association Scores, and the Oswestry Disability Index. The pre- and post-operative radiological evaluations were also reviewed.

Results:

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

Conclusion:

Since the clinical and radiologic outcomes of CBT-DDS were similar to that of MI-TLIF in patients of L4-5 or L3-4-5 spondylosis and spondylolisthesis, CBT-DDS appeared to be a viable and effective alternative to MI-TLIF, and with less operation time and similarly limited segmental motility.