Data presented at the 27th Annual International Meeting on Advanced Spine Techniques (IMAST 2020) provided evidence that decompression and implantation of the LimiFlex™ paraspinous tension band was as good as decompression and transforaminal lumbar interbody fusion (TLIF).
The LimiFlex device, made by Empirical Spine, Inc., based in San Carlos, California, was studied in an investigational device exemption (IDE) trial with 63 patients with symptomatic grade 1 degenerative spondylolisthesis.
The data was presented by Rick Sasso, M.D. of the Indian Spine Group in Carmel, Indiana. He was also co-primary investigator on the 12-month prospective, multicenter trial.
The study determined that all patients improved significantly in terms of Oswestry Disability Index (ODI), and Visual Analog Scale (VAS) leg and back pain scores. Outcomes for patients who received treatment with the study device were not significantly better than those who underwent TLIF surgery, nor were complication or adverse event rates.
However, compared with TLIF the device “significantly lowers operative time, blood loss, and hospital stay,” said Sasso. Sasso concluded his presentation by noting study completion is necessary for determining long term implications of the motion-sparing device.
The device consists of two titanium springs secured alongside the space between the spinous processes with polyethylene straps wrapped around the spinous processes. LimiFlex device is intended to provide stabilization without fusion by limiting spinous process separation, reducing segmental flexion and translation.
Whether LimiFlex can stave off fusion in the long-term will require continuation of the current study, and/or additional studies with long-term follow-up.
Interspinous process (ISP) devices are a relatively new class of device intended to treat low grade spondylolisthesis, and prevent fusion surgery, at least for a period of time. While the LimiFlex reduces flexion, most ISP devices limit extension, though the intended effect is the same.
ISP devices are generally thought to only be intended to extend the life of a motion segment and delay the need for fusion by a few years. However, long-term studies of one of the first such ISP devices, the coflex, now from Surgalign Holdings, Inc., have shown durable motion-preservation and pain relief for at least 5 years. Additional long-term studies of this class of devices will help to shift the mindset of surgeons to consider them as fusion alternatives, instead of delay tactics.
