Abstract
Blumenthal et al (2013) found that segmental facet joint angle (FJA) >50°, disc height (DH) >6.5mm and segmental translation (ST) >1.25mm were associated with higher rates of reoperation in patients who had decompression only, without fusion, for symptomatic degenerative spondylolisthesis (DS). An ongoing FDA IDE study (NCT03115983) is comparing spondyloplasty (decompression and dynamic sagittal tether (DST) stabilization vs decompression and transforaminal lumbar interbody fusion (TLIF) for symptomatic DS. Radiographic measures including those identified by Blumenthal may identify signals among subgroups with clinical success or failure.
The purpose of this analysis is to assess composite clinical success (CCS) among spondyloplasty and TLIF subjects having a PDI.
Post-hoc analysis of data from a multi-center, prospective IDE study of spondyloplasty vs TLIF for symptomatic DS (NCT03115983).
A total of 299 subjects enrolled in the IDE trial of spondyloplasty (N=140) vs TLIF (N=159). Full study inclusion criteria provided at clinicaltrials.gov (NCT03115983).
Primary outcome measure CCS was defined as patients meeting all of the following through 24-months: successful index implantation; 15-point improvement on the Oswestry Disability Index (ODI); no device integrity failure defined as device breakage, separation, dislocation or disassembly; no subsequent surgical intervention (SSI) at the index or adjacent segments; and no decrease in neurologic status unless attributable to a concurrent medical condition or other unrelated cause. PDI were defined as ST>1.25mm, FJA>50° or DH>6.5mm as measured on preoperative radiographs.
CCS rates were calculated for each subgroup of patients having or not having each individual PDI, all PDI, any PDI or no PDI in each of the two treatment arms. Influence of each PDI was assessed using student's t-test to compare subjects with and without the PDI.
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There was no identifiable relationship between any of the preoperative radiographic parameters and clinical success in either the spondyloplasty or TLIF groups. Notably, failures in the spondyloplasty group were not associated with higher preoperative mobility, disc height, anterolisthesis or FJ angle, as has been seen in decompression alone.
LimiFlex Dynamic Sagittal Tether (Investigational/Not Approved), Standard of Care TLIF instrumentation and graft materials (Approved for this indication)