Wenzel Spine out of Austin, Texas received 510(k) clearance from the FDA for its VariLift Expandable Interbody Fusion System. The device is designed to be used at up to two contiguous levels for patients with up to Grade I spondylolisthesis.
VariLift-L is designed to be implanted as a single device via a transverse (TLIF) approach or bilaterally via a posterior (PLIF) approach. VariLift-A is designed to be implanted bilaterally via an anterior (ALIF) approach. VariLift-L and VariLift-A may be implanted with or without supplemental fixation and are intended for use with autograft to facilitate fusion.
In the expanded form, the VariLift device restores disc height, maintains lordosis, gives support to the anterior column, and provides foraminal patency. To implant the device, it is first threaded into the disc space in the unexpanded form. Then, an inner locking expansion washer is advanced anteriorly to spread open the device, expanding it to an angle of 6º
As the VariLift device is expanded, ridges on the superior and inferior surface grip into the vertebral endplates, providing stable primary fixation, as demonstrated in laboratory push-out testing. This immediate post-operative stability is crucial to early ambulation and shorter recovery.
The wedge shape and surface characteristics provide resistance to migration over time. The large bone-contacting area helps avoid subsidence, with a low subsidence rate demonstrated clinically.