Thursday, September 27, 2018 8:30 AM–9:30 AM Best Papers: 107. Analysis of lumbar total disc replacement removals and revisions: a 17-year experience.

BACKGROUND CONTEXT One concern expressed about lumbar total disc replacement (TDR) has been safety. One measure of safety is the need for subsequent surgery to removal or revise an implant. This may be of particular importance considering TDR removal or revision generally requires re-operation through the anterior approach with the corresponding increased risk of vascular injury. PURPOSE The purpose of this study was to analyze the incidence of, and reasons for, removal or revision of lumbar TDR devices. STUDY DESIGN/SETTING Data were collected from a multi-site spine specialty practice. PATIENT SAMPLE A consecutive series of 1,707 lumbar TDR patients, beginning with the first case experience in 2000, was reviewed to identify those undergoing re-operation for TDR removal or revision. Only patients who were at least 6 months postoperative were included. Among the 1,707 patients, the mean follow-up was 42.7 months with a median of 30 months and a maximum of 195 months. OUTCOME MEASURES The primary outcome measure was the occurrence of a surgery for the revision or removal of a lumbar TDR. METHODS For each case of device removal/revision, the reason, duration from index surgery, and procedure performed were recorded. Six different devices were used in the series. RESULTS In the series of 1,707 patients, there were 17 patients who underwent TDR removal (0.99%) and three additional patients underwent TDR revision (0.17%). The rates based on the total number of 2,023 TDR devices implanted in the 1,707 patients, were 0.89% removals and 0.15% revisions. The reasons and timing of removal/revisions were analyzed. Removals included: eight for migration and/or loosening, three developed problems after a trauma, one had vertebral body fractures (osteoporosis), one TDR was too large and replaced with smaller device, one had ongoing pain, and one had an infection seeded from a chest infection at 146 month post-TDR. Revisions included one repositioning the core (technique error), one repositioned device after displacement, and one core replacement due to wear or failure. With respect to timing, 40% of removals or revisions occurred within one month after the index surgery, and a total of 85% occurred within 2 years. Of note, 40% of the revisions/removals occurred in the first 25 TDR cases performed by individual surgeons. There were no vascular complications causing clinical sequelae during the removal or revision surgeries. CONCLUSIONS In this large patient series, 1% of lumbar TDRs were removed or revised. Only one revision was related to device failure or wear. Many of the subsequent procedures were performed within a month of implantation. Also of note, many occurred within the first 25 TDR cases for individual surgeons, suggesting a learning curve. In cases of TDR removal or revision, as with any repeat anterior spine surgery, one should be acutely aware and prepared for vascular injury should it occur. The low rate of removal or revision in this large institutional experience over a 17 year period provides support for the safety of these devices. FDA DEVICE/DRUG STATUS Charite, ProDisc-L, and activL approved for single-level use; Kineflex-L, Freedom, and Flexicore investigational; and Charite, ProDisc-L, and activL off-label for multi-level and hybrid. [ABSTRACT FROM AUTHOR]