Comparison of fusion rate between titanium-coated PEEK cage and PEEK cage for posterior lumbar interbody fusion -80 case study with single surgeon-

<p>Introduction: Nonunion is still major complication after transforaminal lumbar interbody fusion (TLIF). Recently, titanium Ti-coated polyetheretherketone (PEEK) has been introduced, which have advantages of PEEK and titanium. We compared the radiological outcomes of TLIF using a titanium Ti-coated PEEK cages and PEEK cages with a minimum of 1-year follow-up.</p><p>Methods: A total of 80 patients who underwent TLIF using Ti-coated cages (2016-2017) and PEEK cage (2014-15) by a single surgeon were retrospectively reviewed. A total of 37 patients with a total of 48 segments used Ti-coated PEEK cages (TP group), and 43 patients with a total of 51 segments used PEEK cages (P group). The mean age was 69 years old with 38 males and 42 females. Endplate cyst, radiolucent zone, screw loosening, cage subsidence (>2 mm), and fusion rate were evaluated by CT at 3- and 12-months. Bony union was assessed by sagittal and coronal CT-MPR to confirm osseous continuity through the vertebral endplate and cage or to confirm a bony bridge around the vertebrae and less than 2 degrees of motion on flexion-extension in the radiograph. Nonunion was assessed by the presence of a visible gap.</p><p>Results: Solid fusion was achieved in 92% of patients in the TP group and 82% in the P group at 12-months after surgery (P=0.24). There was no significant difference in age, gender, number of fused segments, cage height, operation time, and estimated blood loss between the TP group and the P group. The incidence of endplate cyst was 52% in the TP group and 59% in the P group (P = 0.55) at 3 months after surgery, and 50% in the TP group and 47% in the P group (P = 0.84) at 12-months after surgery. The incidence of screw loosening (TP group 27% vs P group 29%, P=0.83), cage subsidence (TP group 29% vs P group 24%, P=0.65), and radiolucent zone around cage (TP group 17% vs P group 20%, P=0.80) were similar in both groups.</p><p>Conclusions: The present study has demonstrated that Ti-coated PEEK cage did not affect on radiographical outcomes. There are various factors affecting bony fusion in lumbar interbody fusion surgery. The incidences of endplate cysts were also similar in the TP group and P group at 3- and 12-months after surgery. Further studies are needed to identify the predictive factors associated with nonunion.</p>