Image: The Tesera SA Hyperlordotic ALIF interbody spinal fusion system (Photo courtesy of Renovis Surgical).
An innovative anterior lumbar interbody fusion (ALIF) implant feature a porous titanium structure created via additive manufacturing printing technology.
The Renovis Surgical (Austin, TX, USA) Tesera SA Hyperlordotic ALIF interbody spinal fusion system features a highly porous surface structure created using patented Tesera Trabecular Technology (T3), which allows for bone attachment and in-growth to the roughened implant, maximizing strength and stability. The implants are available in 7˚, 12˚, 17˚, 22˚, and 28˚ lordotic angles, with varying heights and footprints for proper intervertebral height and lordosis restoration, and a four-screw design with a locking cover plate to prevent screw backout.
The T3 structure is not simply a coating, but is rather built up in one continuous process that results in a 100% dense titanium alloy structure, with physical properties similar to those of wrought material and a modulus of elasticity that falls within the range of cancellous bone. The large pore size (about 500 μm) provides high initial mechanical stability once the surface prominences grip into the bone, with the subsequent mechanical interlocking of bone growing into the structure providing for long-term fixation.
ALIF is similar to posterior lumbar interbody fusion (PLIF), except that the spine is approached through the abdomen instead of through the lower back. As the anterior midline rectus abdominis muscle runs vertically, it does not need to be cut and easily retracts sideways. The peritoneum can also be retracted, allowing access to the spine without actually entering the abdomen, and thus back muscles and nerves remain undisturbed. In addition, a much larger implant can be inserted through an anterior approach, and this provides for better initial stability of the fusion construct.