LimiFlex™ is a potential alternative to spinal fusion, which has persistent and well-documented drawbacks, including being highly invasive and expensive and carrying a high risk of surgery-related complications and re-operations.
What Is Lumbar Spinal Stenosis?
Spinal stenosis is a common disease of the aging lumbar spine. It involves a narrowing of the space around the spinal cord and the nerve roots in the lower back. This puts pressure on nerves and causes pain, numbness, and weakness in the legs and hips, with an impaired ability to walk and, in some cases, back pain.
What Is Degenerative Spondylolisthesis?
Some patients who have lumbar spinal stenosis also have degenerative spondylolisthesis, where one vertebra slips forward relative to another. The slip causes compression of the spinal canal and associated symptoms. In addition, patients with degenerative spondylolisthesis often have excessive movement, or instability of that part of the spine, when they bend forward and flex their lumbar spine.
Treatment Options
The symptoms of lumbar spinal stenosis can sometimes be successfully addressed with non-operative treatments such as physical therapy and medications. When non-operative treatments fail, surgeons often elect to perform surgical decompression. After such surgical removal of bone and soft tissue that are pushing on the nerves, symptoms usually improve in the short term. However, the removal may increase spinal instability. This can lead to symptoms returning and even becoming worse.
Rigid fixation with pedicle screws and rods with the goal to fuse the hypermobile segment
In some cases, it is necessary to stabilize the treated spinal segment after surgical decompression using a spinal implant. Rigid fixation and fusion is accepted as the gold standard for stabilization of patients with segmental instability.
Fusion Is Invasive and Often Progressive
Fusion has been around for a long time and is a great solution for many patients. However, as a mature technology, fusion’s drawbacks are also well known and persistent. By modern standards, fusion surgery is invasive and lengthy as well as expensive. Moreover, it exposes the patient to significant risk of sequelae.
This series shows one of the major complications of spinal fusion, adjacent level breakdown, which occurs in roughly 30 – 50% of patients in the 5 – 10 years after fusion. In this series you can see the disc above the fused levels collapse in the 18 months after a 3-level fusion due to increased stress and motion related to the fusion below.
As a result, this fusion is extended to the next level in panel F. Adjacent level degeneration represents a major worry for patients and physicians.
An Alternative to Spinal Fusion
The LimiFlex Dynamic Sagittal Tether is a new potential alternative to spinal fusion for patients receiving surgical decompression for grade 1 lumbar degenerative spondylolisthesis with spinal stenosis.
Lumbar spine in flexion
Lumbar spine in flexion with LimiFlex™
LimiFlex is designed to restore natural segmental motion and stability after lumbar decompression by augmenting the posterior tension band. This creates elastic resistance to flexion and maintains lordosis, giving patients the stabilization their spines need while preserving normal motion. The Dynamic Sagittal Tether is intended to be an alternative to spinal fusion, which has persistent and well-documented drawbacks, including being highly invasive and expensive and carrying a high risk of surgery-related complications and re-operations.
LimiFlex uses a novel design that works with the body’s natural anatomy to provide the incremental stability needed by maintaining lordosis and encouraging facet engagement. Unlike interspinous spacers, LimiFlex only engages when a patient bends forward, which avoids delivering excess force and stress on the spinous processes with each step. LimiFlex was designed to act as a ligament to augment the natural anatomy after a thorough decompression for the stenosis. It is compatible with current decompression techniques and is inserted without screws to reduce procedural morbidity and preserve the option for other treatments if needed.