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Lower Spine News

Dynamic Instrumentation an Effective Option for Degenerative Spine Disorders in Some Patients

Patients who are older who have degenerative spine disorder may benefit from a dynamic stabilization of the spine rather than a rigid system.

Rigid instrumentation is often used to fuse the spines of patients with degenerative spinal disorders. However, surgeons have found that patients who undergo such fusion often experience worsening of lumbar lordosis (swayback), increased lower back pain, fractures of the vertebrae, loosening of the hardware (screws), or degeneration of the spinal segments next to the fusion.

The authors of this study compared the results following a rigid stabilization to a dynamic system, one that allows the spine to have more movement and ability to bear weight. The Dynesys system is believed to avoid some of the issues resulting from the rigid fusions.

Fifty patients (33 females) participated in the study. Twenty-five patients, aged 23 to 74 years, were in Group R (Rigid fixation) and 25, aged 24 to 70 years, in group D (Dynesys system). All patients were evaluated clinically with physical examinations, neurological examinations, and x-rays. They were also evaluated through the Visual Analog Scale (VAS) for pain and the Oswestry Disability Index (ODI) for disability. They were evaluated before surgery, and then again at six weeks, six months, one year, and two years following surgery.

The researchers found that the patients in group D had an average VAS scale (on 1 to 10, with 10 being the worst ever pain and 0 being no pain) of 6.9 for lower back pain before the surgery, which decreased to 3.4 two years after surgery. In group R, the VAS score was 7.6 before surgery and 3.7 at two years after. When evaluating VAS for leg pain, group D reported a decrease from 6.2 before surgery to 2.1 at two years; group R reported a decrease from 6.9 before surgery to 3.0 at two years.

When evaluating the ODI, which is out of 100 and the lower the number, the better the score, group D reported an ODI score of 29 at two years after surgery compared with 54 before; group R reported 39 at two years, down from 56 before surgery.

Some patients received more than one fusion in the spine; they reported an ODI score of 35 at two years, compared with 52 before surgery.

The researchers broke down the groups according to age over 50 years and under. Among those over 50 years, group D patients reported an ODI of 25 at two years compared with 50 before. The group R patients reported an ODI of 39 at two years, compared with 62 before surgery. This is interpreted as a greater than 50 percent improvement for those in group D but only more than 25 percent for those in group R. Among the patients who were under 50 years, ODI was 39 at two years for group R, down from 62 before surgery; ODI was 39 at two years for group D, down from 60 before surgery.

Complications were found among 10 patients: three patients experience infections (one in group R, two in group D), one had seroma, or fluid under the skin (group not reported), four had technical errors (three in group R, one in group D), and two had nerve root irritation, both in group R.

The authors conclude that their study indicates use of rigid instrumentation can help patients if this is over a short area, however, use of a dynamic system is helpful for larger areas. They do point out, as well, that the dynamic system does not require donor grafting, eliminating any issues that may arise from taking grafts.

Ganesh Natarajan, Manish Desai, and Muralikuttan. Comparative Study of Rigid Versus Dynamic Spine Stabilization for Degenerative Lumbar Spine Disorders. In Journal of Orthopedics. December 2007. Vol. 4 No. 3. e7.


*Disclaimer:* The information contained herein is compiled from a variety of sources. It may not be complete or timely. It does not cover all diseases, physical conditions, ailments or treatments. The information should NOT be used in place of visit with your healthcare provider, nor should you disregard the advice of your health care provider because of any information you read in this topic.
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