Failure of an expandable lumbar interbody spacer - a critical analysis of secondary collapse, pseudoarthrosis and revision rates after thoracolumbar fusion.

Abstract

To report on the failure rates of an expandable interbody spacer, used for spinal instrumented transforaminal lumbar interbody fusion (TLIF) or posterior thoracolumbar interbody fusion (PLIF). In this retrospective, single-center observational cohort study we reviewed consecutive PLIF/TLIF patients using the Catalyft™ PL and PL40 expandable titanium interbody implant (Medtronic, Minneapolis (USA)) between 07/2022 and 11/2023. We recorded patient demographics, surgical parameters, adverse events, radiological parameters and clinical outcomes according to the MacNab criteria. We identified 53 patients (mean age 68.6 ± 11.5 years; 49.1% female; mean BMI 25.7 ± 4.4 kg/m²), in which 92 Catalyft™ spacers were implanted, mostly at L4/5 (n = 35; 38.0%) and L5/S1 (n = 31; 33.7%) for degenerative (n = 44; 83.0%), deformity (n = 7; 13.2%) or other indications (n = 2; 3.8%). We noticed secondary collapse of 20 (21.7%) spacers in 11 patients (20.7%) occurring after a mean time of 4.0 ± 4.1 months postoperatively. Age < 70 years was identified as risk factor for secondary collapse (OR 3.71, 95% CI 1.31-10.5, p = 0.014), but no association was found regarding other patient-specific or surgery-related variables. Pseudarthrosis was evident in seven patients (13.2%), of which four (7.6%) required revision surgery. Clinical outcome at last follow-up (mean 6.4 ± 4.2 months) was excellent/good in 29 (54.7%), fair in 14 (26.4%) and poor in six patients (11.3%). We provide a critical analysis of our series of patients with use of a specific type of expandable interbody spacer. We noticed failure and secondary collapse in an unacceptably high number of implants, some of which required revision surgery.