Is there a rational basis for post-surgical lifting restrictions? 2. Possible scientific approach

Lifting restrictions postoperatively are quite common but there appears to be little scientific basis for them. Lifting restricitions are inhibitory in terms of return to work and may be a factor in chronicity. The mean changes in functional spinal motion unit (FSU) stiffness with in vitro or computer-simulated discectomies, facetectomies and laminectomies were reviewed from the literature. We modified the NIOSH lifting equation to include another multiplier related to stiffness change post surgery. The new recommended lifts were computed for different lifting conditions seen in industry. The reduction of rotational stiffness ranged from 21% to 41% for a discectomy, 1% to 59% for a facetectomy and 4% to 16% for a partial laminectomy. The recommended lifts based on our modified equation were adjusted accordingly. There is no rational basis for current lifting resctrictions. The risk to the spine is a function of many other variables as well as weight (i.e., distance of weight from body). The adjusted NIOSH guidelines provide a reasonable way to estimate weight restrictions and accomodations such as lifting aids. Such resitrictions should be as liberal as possible so as to facilitate, not prevent, return to work. Patients need more advice regarding lifting activities and clinicians should be more knowledgeable about the working conditions and constraints of a given workplace to effectively match the solution to the patient's condition.