How Often Is Low Back Pain Not Coming From the Back?

Sembrano Jonathan N, Polly David W. Spine 2008;34(1):E27–E32

SI Joint Key Points:

For patients presenting to a spine surgeon’s clinic for LBP, up to 25% of patients may have significant pain contribution from the hip or SI joints.
Study found that the SI joint is a significant pain generator in 14.5% of LBP patients is very similar to the 18.5% and 13% to 30% findings other studies.

Study Design: Consecutive case series cohort.

Objective: To determine the relative frequencies of the spine, SI joint, and the hip joint being the primary pain generator among patients presenting at a spine surgery clinic for low back pain (LBP).

Methods: 368 new patients were seen at a single spine surgeon’s clinic during a 10-month period between August 2006 and May 2007. Of these, 289 (78.5%) complained primarily of LBP with or without leg pain. The remaining 200 cases having no previous surgery were reviewed for all diagnostic tests performed, as well as the final diagnosis.

Results: Of the 200 patients, 114 (57%) were women. Mean patient age was 49.8 years (range: 11-92). Most of the patients 130 (65%) had no history of pain symptoms. 164 (82%) had spine pathology, but only 130 (65%) had spine-only pathology, whereas 35 (17.5%) had a combination of spine plus hip and/or SI joint pathology. An additional 16 (8%) had hip and/or SI joint pathology without spine pathology. 20 (10%) had an undefined pain source. Overall, 25 (12.5%) had hip pathology, and 29 (14.5%) had SI joint pathology.

Discussion: Study has a number of limitations, foremost of which is the lack of a formal diagnostic algorithm implemented during the period of study. Another limitation is the lack of long-term follow–up to verify if patients benefited from the treatment rendered. Our finding that the SI joint is a significant pain generator in 14.5% of LBP patients is very similar to the 18.5% and 13 to 30% findings in the studies of Maigne et al and Schwarzer et al, respectively. Both studies used diagnostic injections as a reference standard.

Conclusion: For patients presenting to a spine surgeon’s clinic for LBP, up to 25% of patients may have significant pain contribution from the hip or SI joints, and an additional 10% will still have an undefined pain source even after diagnostic work-up. This underscores the need for clinicians to be aware of non-spinal pain generators and to appropriately pursue alternative diagnoses.