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

Twenty-seven patients underwent instrumented transforaminal lumbar interbody fusion (TLIF) procedures using bioresorbable implants as interbody spacers. The greater than 2-year clinical and radiographic results of this series are presented along with as a review of relevant preclinical and preliminary clinical studies of bioresorbables.

To determine the clinical suitability of bioresorbable implants used as interbody spacers in spinal fusion surgery applications, particularly in the TLIF procedure.

Bioresorbable technology has been in clinical use by surgeons of a variety of specialties for over 35 years. The use of bioresorbable implants in spine surgery, however, has only been widely investigated in the last several years. The use of slowly degrading bioresorbable implants has the potential for load sharing during fusion when used for interbody applications, retaining imaging quality after fusion, obviating later implant removal, providing biologic barriers as well as other various applications. Animal studies and early clinical series with the use of these materials for a variety of indications have been encouraging.

This study evaluates the use of bioresorbable polymer spacers manufactured with a 70:30 copolymer of poly-L-lactide and D,L-lactide as interbody spacers in 27 of 31 patients with 2 years or more follow-up who underwent instrumented TLIF for primarily degenerative indications.

At a mean of 31.9 months follow-up, 25 patients (92.6%) were judged to have solid fusions and 22 patients (81.5%) had good to excellent results. Three patients (11.1%) experienced complications, none of which were directly or indirectly attributable to the use of the bioresorbable polymer implant. Only one implant in 1 patient (3.7%) demonstrated mechanical failure on insertion, and that patient exhibited no clinical sequelae.

Bioresorbable implants have significant potential for use in spine surgery. This potential is realized in this first published clinical series using bioresorbable implants as interbody spacers with a minimum follow-up of 2 years, significantly exceeding the biologic "life expectancy" (12-18 months) of the implant material. Both the clinical and radiographic results of this study support the use of interbody devices manufactured from bioresorbable polymers for structural interbody support in the TLIF procedure.