106 - Incidence of Implant Removal or Revision Surgery after Cervical Total Disc Replacement in a Consecutive Series of 1,615 Patients Beginning with the First Case Experience in 2003

Introduction
Cervical total disc replacement (TDR) has gained acceptance as an alternative to fusion in appropriately selected patients. Clinical outcomes have consistently been reported to be similar or superior to anterior cervical discectomy and fusion (ACDF). Initially, there were concerns about the safety or these devices. One measure of safety is the need for subsequent surgery related to problems with the devices.
Aims/Objectives
The purpose of this study was to investigate the rate of cervical TDR device removal or revision.
Methods
The study was based on the consecutive series of 1,615 cervical TDR patients, beginning with the first case experience in 2003 and ending with cases in December of 2020, to allow minimum 2-year post-operative duration. The series included TDRs at one, two, or three levels, and hybrids. A comprehensive case log was reviewed to identify cervical TDR cases and subsequent surgeries for these patients. Cases of TDR removal/revision were recorded as well as the reason for the subsequent surgery, procedure performed, and duration from the index procedure. General patient descriptive information was also recorded. Data were analyzed to determine the rate of removal/revision surgery, as well as patient and surgeon factors possibly related to the removal/revision event.
Results
In the series of 1,615 patients, there were 20 cases of TDR removal or revision, producing a rate of 1.24%. Removal was performed in 19 cases (1.18%) and revision performed in 1 case (0.06%). Among the 19 removal cases, in 16 patients the TDR was removed and fusion performed and in 3 cases, the TDR was removed and replaced with another TDR. Based on the 2,097 TDR devices implanted, the rate of revision/removal was 1.00% (21 devices). Removals with fusion performed included 5 cases of osteolysis with/without C. acnes, 4 involved device displacement/migration (one due to trauma in one case and due to incorrect device size in another), 5 posterior spinal pathology (stenosis, facet changes, etc.) and one of each of the following: presumed metal allergy, approach-related esophageal tear and subsequent complications, malalignment (also included adjacent segment degeneration), subsidence, and hypermobility. The only revision was repositioning of the TDR (positioned off midline and patient had new onset radiculopathy) performed 6 days after the index surgery. In all of the removal/revision cases, the procedures were performed as planned without incident. The mean duration from TDR implantation to removal was 23.4 months (range from 0 to 67.5 months) There were 424 patients who were a minimum of 10 years post-TDR, but none of these patients had removal/revision surgery at 10 or more years after the index surgery. Logistic regression analysis found no relationship between the occurrence of removal/revision and factors of age, gender, body mass index, or physician experience with cervical TDR (learning curve).
Conclusion
In this large consecutive series of patients, 1.24% of cervical TDRs were removed/revised. There was no indication of increasing removal/revision rates with post-operative duration. This low rate of removal/revision in this large institutional experience over a long period of time provides support for the safety of these devices.