Initial data from LimiFlex IDE trial presented at IMAST 2020

Rick Sasso

Initial results of a US Investigational Device Exemption (IDE) trial studying use of a novel paraspinous tension band (LimiFlex, Empirical Spine) for the treatment of degenerative spondylolisthesis have been presented online as part of the 27th Annual Meeting on Advanced Spine Techniques (IMAST 2020). The study’s co-primary investigator Rick Sasso (Indiana Spine Group, Carmel, USA) said that the 12-month results of the prospective, multicentre trial showed that the device “significantly lowers operative time, blood loss and hospital stay” compared to instrumented transforaminal lumbar interbody fusion.

Introducing his presentation, Sasso noted that the surgical standard of care for symptomatic degenerative spondylolisthesis causing radiculopathy is decompression and instrumented fusion, but commented that this is associated with morbidity of the fusion procedure. The paraspinous tension band has been designed as a minimally invasive alternative to fusion after decompression, and is comprised of a set of titanium springs and polyethylene straps to preserve motion in the patient. Sasso presented data from 63 patients involved in the IDE study, of whom 38 were implanted with the paraspinous tension band, and 25 received decompression and transforaminal lumbar interbody fusion.

Standard outcome measures assessed in the IDE trial included Oswestry Disability Index (ODI) and visual analogue score (VAS) leg and back scores. Both groups demonstrated significant improvements in ODI at 12-month follow-up, Sasso said, with no statistically significant difference between them. In terms of VAS pain outcomes, both cohorts demonstrated statistically significant improvements, Sasso noted, again with no statistically significant difference between the two groups. Complications and adverse events were also similar in both groups.

Sasso also presented a case study involving a 64-year old man with a five-year history of back and leg pain, secondary to grade 1 degenerative spondylolisthesis at the L4-L5 vertebral bodies, causing L5 radiculopathy. The patient was discharged on the same day as his operation on an outpatient basis, with 50cc blood loss, Sasso said. At 12 months postoperatively, his ODI decreased from 46 to 0 and he reported no leg or back pain; flexion/extension X-rays showed no difference in range of motion or dynamic translation after the surgery.

In conclusion, Sasso noted that decompression and paraspinous tension band had significantly lower operative time, blood loss and hospital stay compared to decompression and instrumented transforaminal lumbar interbody fusion. He added that completion of the study and further, longer term follow-up is necessary to determine the role that this motion-sparing device may have as an alternative to fusion for patients with systematic degenerative spondylolisthesis.

Sasso and colleagues were nominees for the Whitecloud Award for Best Clinical Paper at IMAST 2020.


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