Validation and Use of an Induced-Pain Paradigm to Investigate Risk Factors for Low Back Pain Development during Prolonged Standing
Date of Award
Doctor of Philosophy (PhD)
Chair and Committee
Linda R Van Dillen
Catherine Lang, Michael Mueller, Barbara Norton, Shirley Sahrmann, Simon Tang, Dequan Zou
Epidemiologic studies have shown jobs that involve prolonged standing are associated with increased risk of developing low back pain (LBP). Although standing for prolonged periods of time is common, not all people who are exposed to prolonged standing will develop LBP. Factors that cause an individual to be susceptible to LBP development during prolonged standing are not well understood. Recent studies have used an induced-pain paradigm to understand the characteristics that may predispose a person to developing LBP during prolonged standing (standing paradigm). The standing paradigm consists of back-healthy people standing for 2 hours in a confined area while performing simulated, light work tasks. LBP symptom intensity is rated throughout the 2 hours. Based on symptom intensity ratings throughout standing, a participant is considered to be either a pain developer (PD) or a non pain developer (NPD). The primary goals of this dissertation project were to (1) examine the validity of the standing paradigm, and (2) identify risk factors for LBP development during standing.
In chapter 2, we examined the validity of the paradigm by comparing characteristics of symptoms (quality and location) experienced during standing (1) to symptoms reported as "typical" by people with LBP, and (2) between people with LBP and PDs. We found the quality and location of symptoms reported during standing by people with LBP were not different from (1) their typical symptoms and (2) symptoms developed by back-healthy people during the standing paradigm. In chapter 3, we examined lumbar lordosis in PDs and NPDs. We found that (1) PDs displayed more lumbar lordosis than NPDs and (2) the amount of lumbar lordosis was related to LBP symptom intensity in PDs. In chapter 4 we examined timing of lumbopelvic motion during the active hip abduction test in PDs and NPDs. We found that (1) PDs displayed more right to left asymmetry of timing of lumbopelvic movement than NPDs and (2) that the amount of asymmetry was related to LBP symptom intensity in PDs. In chapter 5, we examined the relationship between LBP symptom intensity and psychological factors in back-healthy people who develop LBP during prolonged standing. We found that if symptom intensity exceeded a clinically meaningful threshold during standing, LBP symptoms were related to the psychological factors. In chapter 6, we examined whether the incidence of LBP episodes in the 6 months following participation in the standing paradigm differed between PDs and NPDs. We found that there was a trend towards a larger proportion of PDs that reported an episode of LBP than NPDs.
The results of this dissertation (1) strengthen the validity of the standing paradigm as a method for understanding LBP development during standing and (2) provide information about potential risk factors for LBP development during prolonged standing. More studies are needed to continue to investigate factors that may lead to LBP development during standing and if PDs are at greater risk for future episodes of LBP.
Sorensen, Christopher J., "Validation and Use of an Induced-Pain Paradigm to Investigate Risk Factors for Low Back Pain Development during Prolonged Standing" (2015). WUSM Theses and Dissertations – All Programs. 1.