An innovative method using the Leeds-Keio artificial ligament in the unstable spine.

We have designed two innovative surgical procedures using the Leeds-Keio artificial ligament to solve the difficult problems caused by the difference in physical properties between bone structure and spinal implants, such as pedicle screw systems, used for treating the unstable lumbar spine. The procedures aim at intervertebral immobilization or reinforcement of a posterior lumbar interbody fusion. Twenty-one patients with over 2 years of follow up were evaluated. The clinical results showed these procedures to be advantageous compared with various pedicle screw systems. We conclude that these combined procedures may be applicable to patients with various types of unstable lumbar spine problems who, until now, were treated with instrumentation surgery. The best indications for these two procedures are degenerative spondylolisthesis or degenerative disk lesion with various instabilities, degenerative canal stenosis for which wide laminectomy is essential, and herniated disk with instability during flexion.