A study published in Clinical Spine Surgery examines the biomechanics of posterior dynamic fusion in the lumbar spine.
The study included six fresh-frozen lumbar cadaver specimens that underwent unilateral transforaminal lumbar interbody fusion with a cage that had an integrated load cell. The researchers also placed pedicle screws and implanted the Isobar. Then a rigid rod replaced the Isobar in the same pedicle screw arrangement.
The researchers found:
1. The Isobar performed comparably to the rigid rod for range of motion; there wasn't a statistical difference between the two.
2. The difference between the intact and rigid rod and the intact and Isobar conditions in the flexion extension was significant.
3. There was a significant increase in flexion extension for interpedicular displacement when comparing the Isobar to the rigid rod.
4. There was increased anterior column loading under the axial compression when compared with the rigid rod.
5. The researchers concluded, "By increasing perpendicular displacement and AL, it potentially brings clinical benefit to procedures relying on arthrodesis."