In-Space Interspinous Distraction

Paul Pavlov, Frank Kandziora, Robert McGuire
The in-space interspinous distraction device has been available in Europe since 2006. This device was designed to be a minimally invasive alternative to existing interspinous distraction devices or decompression surgery. In-space is available in two approaches: the lateral, percutaneous approach requires only a small incision of 2 cm, while the posterior, mini-open approach requires an incision of 36 cm. Both approaches are less invasive compared to the incision needed for a standard decompression surgery.

With the growth of the aging population, the incidence of lumbar spinal stenosis continues to increase. Decompression of the affected spinal level may be performed to relieve pressure off the spinal cord or nerve roots.

As a less invasive alternative for suitable patients in the form of interspinous devices are available to act as an extension stopper, since it is this motion that places additional pressure on the affected neural structures and causes pain. Patients with central, lateral and foraminal lumbar spinal stenosis with leg, buttock, or groin pain, which can be relieved during flexion, are good candidates for this procedure.

For the percutaneous approach, a guide wire is inserted to the spinal level that needs to be distracted. Next, distractors are placed sequentially one over the other until adequate distraction is reached. Finally, the implant is inserted and wings are deployed to help keep the implant in place.

With the posterior, mini-open approach, muscles only need to be stripped unilaterally, therefore it is less invasive than some competitors bilateral approach. Trial distractors are placed sequentially one after the other until adequate distraction is reached. The final step, as with the lateral approach, is to insert the implant and deploy the wings.

Both surgical approaches are aided by x-ray imaging, to better visualize proper placement of the in-space. Unlike standard decompression surgery, in-space does not require the removal of any bone and supporting ligaments remain uncompromised. Thus, spinal stability is not affected by the procedure.

A single level in-space surgery is typically performed in 15-35 minutes, significantly less compared to decompression surgery. Therefore, and due to the minimally invasive nature of the procedure, patients tend to experience less postoperative pain, minimal bleeding, and a shorter hospital stay, followed by a quicker return to daily activities.

It is important to note that interspinous technology is not a cure-all. It is only one step in the continuum of surgical treatment for degenerative spinal disorders.

Case provided by Paul W Pavlov, Nijmegen, The Netherlands

32-year-old male with neurogenic claudication due to spinal stenosis (degenerative bulging discs). Complete relief of symptoms.




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