Instrumented transforaminal lumbar interbody fusion with bioabsorbable polymer implants and iliac crest autograft

Object. The purpose of this study was to evaluate the clinical and radiographic results in 31 patients from one center who underwent instrumented transforaminal lumbar interbody fusion (TLIF) for primarily degenerative indications. Methods. Bioabsorbable polymer spacers manufactured with a copolymer of 70:30 poly(L-lactide-co-D,L-lactide) and filled with iliac crest autograft bone were used for the TLIF procedure. In this paper the details of this procedure, intermediate (1- to 2-year) clinical and radiographic outcomes, and the basic science and rationale for the use of bioabsorbable polymers are discussed. At a mean of 18.4 months of follow up, 30 patients (96.8%) were judged to have attained solid fusions and 25 patients (81%) had good to excellent results. Three patients (9.7%) experienced complications, none of which were directly or indirectly attributable to the use of the bioabsorbable polymer implant. Only one implant in one patient (3.2%) demonstrated mechanical failure on insertion, and that patient experienced no clinical sequelae. Conclusions. This is the first clinical series to be published in which the mean follow-up duration equals or exceeds the biological life expectancy of this material (12-18 months). Both the clinical and radiographic results of this study support the use of interbody devices manufactured from biodegradable polymers for structural interbody support in the TLIF procedure.