A prospective cohort study evaluating the quantitative lumbar flexion-relaxation phenomenon (QLFRP), measured with surface electromyographic (SEMG) signals from the erector spinae during trunk flexion pre- and postrehabilitation, in patients with chronic disabling occupational lumbar disorders (CDOLD).
To assess the responsiveness of the QLFRP in documenting change in functional performance during a functional restoration program for CDOLD patients.
A recent theoretical construct suggests that QLFRP is responsive to change in lumbar range of motion (ROM) during rehabilitation, with high sensitivity and specificity for abnormal QLFRP predicting ROM.
A cohort of normal subjects was tested for QLFRP correlated to inclinometric lumbar ROM measures. The cutoff score was applied to a group of CDOLD patients entering a functional restoration program (N = 135), and to program completers (N = 104). Pain and functional self-report scores were compared with SEMG and ROM measures.
The CDOLD group averaged 23.7 months off work. Surgical treatment was provided prerehabilitation to 51% of patients, with 29% receiving lumbar fusions. From pre- to post-treatment, achievement of QLFRP rose from 31% to 74% of patients, while normal ROM rose from 8% to 63% of patients. Compared to the 16% of patients still demonstrating both abnormal QLFRP and ROM, the other groups showed significantly greater improvement in self-reported pain and function, with the best improvements occurring in patients showing normal ROM and QLFRP. The QLFRP showed high sensitivity, but only modest predictive validity and specificity for predicting ROM postrehabilitation. Improvement in sensitivity and predictive validity occur when surgical cases were excluded from the analysis.
A majority of patients in an interdisciplinary functional restoration program failed to demonstrate either the QLFRP or normal ROM on admission to the program. A majority of program completers, however, achieved both normal ROM and QLFRP and another 30% demonstrated either normal QLFRP or normal ROM. Both QLFRP and ROM measures were responsive to relevant self-report scales.
The quantified lumbar flexion relaxation curve was assessed in a group of chronic disabling occupational lumbar disorder patients. Improvements in both the quantitative lumbar flexion-relaxation phenomenon and range of motions measurements were documented in a majority of program completers, and these improvements correlated highly to improvements in pain and function.
From the *Department of Orthopedic Surgery, Southwestern Medical Center, University of Texas, Dallas, TX; †PRIDE Research Foundation, Dallas, TX; and ‡Department of Psychology, College of Science, University of Texas, Arlington, TX.
Acknowledgment date: January 27, 2009. Acceptance date: March 30, 2009.
The manuscript submitted does not contain information about medical device(s)/drug(s).
No funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript.
Address correspondence and reprint requests to Tom G. Mayer, MD, PRIDE Research Foundation, 5701 Maple Ave, Suite 100, Dallas, TX 75235; E-mail: firstname.lastname@example.org.