Abstract and Introduction

Abstract

Study Design: Consecutive case series cohort.

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

Summary of Background Data: Identification of the primary pain generator in a patient with LBP is difficult. Possible pain sources include the lumbar spine, the SI joint, and the hip joint. Their relative frequencies among patients presenting at a spine surgeon's clinic have not been well established.

Methods: Three hundred sixty-eight new patients were seen at a single spine surgeon's clinic during a 10-month period. Of these, 289 (78.5%) complained primarily of LBP with or without leg pain. Seventy-seven had previous surgery. The remaining 200 cases were reviewed for all diagnostic tests performed, as well as the final diagnosis.

Results: One hundred sixty-four (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. Twenty (10%) had an undefined pain source. Overall, 25 (12.5%) had hip pathology, and 29 (14.5%) had SI joint pathology.

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 workup. This underscores the need for clinicians to be aware of nonspinal pain generators and to appropriately pursue alternative diagnoses.

Introduction

Identification of the significant pain generator(s) in patients with low back pain (LBP) remains one of the biggest challenges to a spine specialist. In general and from an anatomic standpoint, pain may arise from the spine itself (which may need to be further localized), the sacroiliac joint,^[1,2] or the hip joint.^[3] Other possible but presumably less common origins of pain are the retroperitoneal structures within the abdominal and pelvic cavities. Yet, despite LBP being the most common type of pain reported by adults,^[4] the second leading cause of disability,^[5] and the leading cause of job-related disability in the United States costing Americans more than $50 billion dollars per year,^[6] there had been no consensus on the relative frequency of different anatomic sites as major pain generators nor on an algorithm on the proper diagnostic workup of these patients.

Our question, therefore, was: what are the relative frequencies of the spine, the sacroiliac joint, and the hip joint being the main pain generator among patients who present with low back pain at a spine surgeon's clinic? We addressed this question through a review of clinic notes on consecutive patients with a complaint of LBP with or without leg pain and noting the final diagnosis arrived at after appropriate workup. The answer to this question may then allow us to predict the pretest probability of alternative diagnoses and overlapping symptomatology among spine specialists, and to better formulate diagnostic recommendations.