Quantification of a meaningful change in low back functional impairment -

Quantification of a meaningful change in low back functional impairment.
Author(s): Ferguson, SA; Marras, WS; Burr, DL; Woods, S; Mendel, E; Gupta, P
Journal: Spine (Phila Pa 1976) 2009 Nov 13; Vol. 34, Issue 19; Page(s) 2060-5

STUDY DESIGN: Repeated measures study design. OBJECTIVE: Determine a meaningful change in low back functional impairment as measured with the lumbar motion monitor. SUMMARY OF BACKGROUND DATA: A quantitative functional performance probability (P(n)) measure has been developed and is scored from 0.00 to 1.00. Previous research has shown that a 0.5 cut-off provides excellent sensitivity and specificity for identifying impaired and healthy low back function. However, a meaningful change in the P(n) measure has not been defined. METHODS: The lumbar motion monitor was used to repeatedly measure P(n) in 3 groups of subjects including (1) asymptomatic, (2) recovering low back pain (LBP) and, (3) nonrecovering LBP. The asymptomatic group had 20 subjects. The recovering and nonrecovering LBP had 18 and 8 subjects, respectively. The asymptomatic group was tested 5 times at 1-week intervals. The 2 LBP groups were tested every 2 weeks for 3 months (6 evaluations). RESULTS: The P(n) in the asymptomatic group did not significantly change over the observed period. On the basis of the variability in the asymptomatic group it was hypothesized that a meaningful change in P(n) was 0.14. The defined meaningful change was evaluated in 2 patient with LBP populations. The P(n) in the recovered LBP group significantly improved during the 3 month observation period and there was a corresponding reduction of symptoms. In the recovering LBP group the within subject standard deviation was 0.14 and all patients had at least 1 visit to visit change greater than 0.14. Furthermore, 11 of the 18 recovering patients with LBP had a meaningful change between the first 2 visits. In contrast, none of the nonrecovering LBP group had a meaningful change between the first 2 visits. CONCLUSION: A meaningful change in P(n) was defined as 0.14.

Spine (Phila Pa 1976). 2009 Sep 1;34(19):2060-5.
Department of Integrated Systems Engineering, The Ohio State University, Columbus, 43210, USA.
Email: ferguson.4@osu.edu