Background: The currently reported incidence of primary sacroiliac joint (SIj) pathology ranges from 15% to 30%. The differential diagnosis of SIj region pain includes pain generated from the lumbar spine, the SIj, and the hip joint. The origins of SIj dysfunctions are controversial and pain generation from this joint has been questioned.
Purpose: Retrospectively analyze the relative incidence of lumbar spine, SIj, and hip joint etiologies in patients complaining of ≥50% SIj region pain.
Study design: This is a retrospective cohort case series.
Methods: Inclusion criteria: chief complaint SIj pain (≥50% of overall complaint). In total, 124 patients charts were reviewed from a single spine surgeon's clinic. All patients were evaluated by the same 2 practitioners and all cases were reviewed for clinical examination findings, diagnostic tests performed, final diagnosis, treatment, and clinical follow-up.
Results: After complete diagnostic workup, 112 (90%) had lumbar spine pain, 5 (4%) had hip pain, 4 (3%) had primary SIj pain, and 3 (3%) had an undetermined source of pain upon initial diagnosis. SIj pain generation was confirmed via fluoroscopy-guided diagnostic injections. Following designated treatment, 11 (9%) patients returned to clinic at an average of 2.4 years complaining of continued/recurrent SIj region pain. Further investigation revealed 6 patients had confirmed pain generation from the lumbar spine, 3 patients had confirmed pain generation from the SIj, and 2 patients had undetermined sources of pain.
Conclusions: The SIj is a rare pain generator (3%-6%) in patients complaining of ≥50% SIj region pain and is a common site of referral pain from the lumbar spine (88%-90%). Clinicians ought to quantify areas of pain (via percent of overall complaint) when interviewing their patients complaining of low back pain to distinguish potential pain generators. Recommended breakdown of areas of interest include axial low back, SIj region, buttock/leg, groin/anterior thigh.