InterLaminar Decompression and Instrumentation
Spinal stenosis is a very common problem afflicting many people after the age of 60. It should not be considered a disease, but rather a normal process of aging.
The degenerative cascade is the process by which the disk degenerates or collapses. Because of the collapse, the facet joints of the posterior spine rub abnormally against each other, causing the bone to enlarge. For my older patients, many of you will find that the joints of your fingers have enlarged over time. That is the same process. The bones rub against each other, causing wear of the cartilage. The bone responds to the pain on the cartilage by enlarging the surface area between the bones. This enlargement is the development of the widening bones. In the spine, this enlarging of the bones will cause pressure on the nerves that travel through the spine. That is the so called “bone spur”, pinching the nerve. In addition, as the disks collapse, the rims of the disk naturally bulge out. Some of the bulging can cause some narrowing of the space for the nerve. The final cause of spinal stenosis is secondary to the effects of the narrowing of the space by the disks. There are ligaments called the ligamentum flavum that are normally stretched between the bones of the spine. With narrowing of the disks, these ligaments are no longer stretched or taut. It will cause a shortening, and widening or hypertrophy of the ligament. This widened ligament can also contribute to the narrowing of the space for the nerve.
Degenerative spinal stenosis is usually a combination of the bone spurs, the narrowing of the disk, and the widening of the ligaments covering the spinal nerve.
Traditional treatments for spinal stenosis included activities modification, NSAID medications and exercise. Recent studies have not demonstrated a usefulness of epidural steroid injections for these patients, though many still request the injection.
Surgical options depend on many factors, and not all patients are candidates for surgery. In general, the main goal of surgery was to remove pressure on the nerves. In certain situations, there is an instability component that necessitates fusion along with removing pressure on the nerve.
In the past 10 years, there has been more and more interests in so called interspinous ligament devices. The rationale is that a device designed to stretch the ligaments, and restore some of the disk height may relieve the spinal stenosis pressure. The devices have had some success, but some patients will still require formal surgery to directly remove pressure on the nerve.
As these concepts evolved, an interlaminar device called the Coflex, from Paradigm spine has been studied for efficacy. The concept is relatively simple. A more traditional limited removal of bone and ligaments off the nerve is performed. then a U shaped device is placed in between the spinous processes, thus achieving some of the height restoration, facet off loading, and opening of the foramen. In addition, secondary to the more traditional laminectomy/laminotomy, the surgeon has direct visualization of the nerves being relieved of pressure.
In my experience, for the properly selected patient, this is a very reasonable option for patients with localized spinal stenosis and with low grade instability.
The procedure can be done on an outpatient basis for select patients. There is no fusion associated with this technique.
- Röder C, Baumgärtner B, Berlemann U, Aghayev E. Superior outcomes of decompression with an interlaminar dynamic device versus decompression alone in patients with lumbar spinal stenosis and back pain: a cross registry study. Eur Spine J. 2015 Oct;24(10):2228-35. PubMed PMID: 26187621
Hi my name is Dr. John Shim, and I want to discuss the lumbar Co flex interlaminar stabilization surgery. By now you have already tried non-surgical treatments, and have decided to move forward with surgery. Lumbar Coflex interlaminar stabilization is offered because your pain patterns match the spinal stenosis findings on your diagnostic studies. Spinal stenosis means narrowing and pinching of the nerve tissues in the spine. Because surgery will remove some of the important stabilizers of the spine. the coflex interlaminar stabilization procedure along with bilateral lumbar laminotomy decompressions are recommended. Let me show you a typical lumbar MRI of spinal stenosis. This is the sagittal view. It's a side view of your back. For most patients, there are some normal disc levels, but with spinal stenosis, you can see the narrowing of the canal by a combination of bone spurring, ligament enlargements, and disc bulging. The axial view, or the cross-sectional view will provide another angle to visualize spinal stenosis. When compared to a more normal level, you can see the triangular shape of the canal, and the narrowing of the space that is occupied by the nerves that are extending from the spinal cord into the lower body. Of course, I'm simplifying the process. For the surgeon, there are many nuances that need to be considered. Experience does help when planning the operation. Still, the exposure is relatively the same. For a single level, a 4 centimeter incision is made in the midline, spanning across the area of bone removal. Muscles are gently retracted to allow visualization of the boney covering or lamina and the ligament that covers over the spinal canal. Some bone in the middle will need to be removed to allow access. The posterior spinal ligament is removed. Tools including burs, kerrison punches and curettes aid in the removal of the covering bone and ligament. The nerve sack is identified, and protected. Associated bone spurs are removed, and the nerves are given more room to exit the space called the formen. The spine is prepared to accept the coflex interlaminar device. Trial devices are used to measure the appropriate size the device. The device is then implanted to within a few millimeters of the thecal sac, and the fins of the device rest on the lamina of the upper and lower spinal levels. The fins are then compressed onto the posterior spinous processes, securing the device to the spinal bones. The incisions are then closed. If there are no issues, most patients can have the surgery performed on an outpatient basis. For the vast majority of patients, they can resume normal activities within a few weeks. This is the basic animation of the lumbar Co flex interlaminar stabilization operation. You should discuss your individual concerns with your surgeon. This is Dr. John Shim, and I hope this video helps you understand the basics of the lumbar Co flex interlaminar stabilization surgery. Thank you!