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Lower Spine News

Taking Off Work Before Back Surgery May Not Be Such a Good Idea

Artificial disc replacements for degenerative disc disease are new enough that many details about their use, success factors, and variables that predict outcomes are still being studied. One of those variables is the effect of time off from work before surgery. In this study, researchers from the Texas Back Institute Research Foundation tell us what they found about this topic.

Is there a certain time period that a patient could be off work and still have a successful surgery with a disc replacement? Conversely, is there a length of time off work that would suggest the patient shouldn't have the procedure done because the results would be compromised?

Right now, studies report a success rate for disc replacement anywhere between 63 and 90 per cent. The question is: why do some patients get better results than others? There may be certain predictive factors that could help guide patient selection. Choosing the right patients for the procedure could consistently ensure a success rate closer to the 90 per cent mark.

At least one other study has shown that time off from work before disc replacement is an important factor. And other studies have shown the same thing for spinal fusion. In this study, the length of time off work before surgery was the key focus of interest. They compared a group of patients who had a total disc replacement with another group who had lumbar arthrodesis (fusion).

Everyone treated in both groups had been diagnosed with degenerative disc disease. Their ages ranged from 21 to 60 years old. They had all been treated conservatively (without surgery) for pain but without success. These patients were enrolled in a FDA-regulated trial cdomparing the results of these two treatments for disc degeneration. That's where the information and data for this study came from.

Only people who were previously employed were included. Students, homemakers, retirees and others who were not working by choice were not included. Anyone with a history of mental illness or serious psychologic problem was also excluded. Anyone involved in a legal battle was not included.

Everyone was followed for a full two years after surgery. Patients in the two groups were compared based on age, gender, insurance type, body mass index, occupation, and number of weeks off work before surgery. Number of vertebral levels (one, two, or three) operated on was analyzed as a possible independent factor.

A well-known test of pain and disability for patients with low back pain was used as the main measure of results. The test is the Oswestry Disability Index (ODI). It is the most commonly used outcome measure for low back pain. This questionnaire was been designed to give us information about how a patient's back (and/or leg pain) affects the ability to manage in everyday life.

Questions are asked about how pain affects ten areas of daily function (e.g., standing, personal care, sleeping, lifting, social and/or sex life, walking, travel). A numerical score is calculated for the test. Each of the 10 items is scored from zero to five. The maximum score is 50. The obtained score can be multiplied by 2 to produce a percentage score. When using the interval scale of zero to 50, results are interpreted as follows:

  • 0 - 4 = no disability

  • 5 - 14 = mild disability

  • 15 - 24 = moderate disability

  • 25 - 34 = severe disability

  • above 34 = complete disability

    After analyzing all the data, improvement in pain and function were greater in the fusion or disc replacement patients who were off work the shortest amount of time. The longer patients were off work before surgery, the worse their scores were and the smaller their improvement. The cutoff period of time in this study was 13 weeks. Patients who were off work for less than 13 weeks had better results compared with those who were off work longer. Patients off work for more than 13 weeks still showed improvement, just not as much as the group with the shorter off-work duration.

    In summary, it looks like time off from work before surgery is related to results of artificial disc replacement or intervertebral fusion. The authors weren't sure how to interpret this finding. It wasn't because one group had more pain before surgery. Maybe there's a psychologic or behavioral reason to explain the difference.

    Further study is needed to look at this concept a bit closer. If in fact it's true that time off work makes a difference, then it may be necessary to rethink how patients are selected for artificial disc replacements. Psychologic screening before surgery for patients off work more than 13 weeks may help show surgeons which patients won't have a good result no matter what or when surgery is done.

    It will take some time to find out if there is an absolute number of days/weeks off work before surgery should be passed up. The authors think it might be possible that telling patients to stay on the job as long as possible could help improve their results after surgery. Or maybe there's a different way to approach postoperative rehab that could lead to better results for patients who have been off work for too long.

    It's been suggested that a few extra weeks of rehab may be needed after surgery to improve results in patients who have been inactive for so long. A similar study assessing the optimal number of weeks in rehab might shed some light on the results of this study.


    Michael X. Rohan, Jr. DO, et al. Relationship Between the Length of Time Off Work Preoperatively and Clinical Outcome at 24-Month Follow-up in Patients Undergoing Total Disc Replacement or Fusion. In The Spine Journal. May 2009. Vol. 9. No. 5. Pp. 360-365.

    05/13/2009

    *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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