PEEK versus metal cages in posterior lumbar interbody fusion: a clinical and radiological comparative study

Background: Low back pain and sciatica represent a common disabling condition with a significant impact on the social, working and economic lives of patients. Transforaminal lumbar interbody fusion (TLIF) is a surgical procedure used in degenerative spine conditions. Several types of cages were used in the TLIF procedure. Purpose: To determine whether there is a difference in terms of symptomatology improvement, return to daily activities and fusion rate between metal cages and polyetheretherketone (PEEK) cages. Methods: We have retrospectively reviewed 40 patients who have undergone TLIF from October 2015 to May 2016. All patients were clinically evaluated with questionnaires and were assessed with CT scan and standing X-ray films of the full-length spine. Results: We found no significant functional differences in the two groups. At 1-year follow-up, osteolysis was present in 50% of cases of the PEEK cages and in 10% cases of the metal cages. The degree of fusion at 1 year was evaluated as complete in 40% cases of the metal cages and 15% cases of the PEEK cages. Conclusions: We have found a better fusion rate and prevalence of fusion in the group treated with metal cages, reflecting the well-known osteoinductive properties of titanium and tantalum.