Spinal fusion is performed in the treatment of severe back pain or a neurological deficit that has not responded to conservative treatment. The symptoms are caused by compression on a nerve or nerve root, commonly as a result of: damaged discs (discogenic pain or degenerative disc disease), abnormal slippage and motion of the vertebra (spondylolisthesis or spondylolysis), or other degenerative spinal conditions, including facet joint degeneration. Spinal fusion may be indicated for any condition that causes excessive instability of the spine, such as certain fractures, infections, tumours, and spinal deformity (such as scoliosis).
The Unity+ is intended as a treatment option for pain and functional disorders specific to the lumbar vertebral column. The aim of the device is to provide support between two vertebral bodies and initial immobilization of these bodies whilst simultaneously providing space for bone graft so that a fusion of the two vertebral bodies will in time be attained.
The Unity+ system consists of a body manufactured from PEEK-OPTIMA, with two titanium-alloy imaging markers bilaterally, a titanium-alloy lateral screw plate with four tapered locking thread screw holes, and four locking bone-anchoring screws (two for each vertebra); the two posterior screws are parallel, while the two anterior screws are angled anteriorly. The device also incorporates two large bone graft windows to accommodate bone graft or synthetic bone inserts.
The Unity+ is anatomically-shaped to fit the lumbar disc space optimally, with three lateral lengths and multiple heights to restore disc height. Surface serrations prevent the device from being displaced between the vertebrae. The device is also provided with a lordotic angle for treatment of lordosis. Large bone graft windows accommodate bone graft or synthetic bone inserts, improving the osseointegration with the endplates. Due to its good 'bone anchoring' the Unity+ is often employed as a 'stand-alone' fusion device.