J. Maier
Background: Thrust in arterial bends causes enhanced pulsatility. Purpose: To study the association between tortuous iliac arteries and lateral low back pain, hypothesizing that pulsatile microtrauma is inflicted on the psoas muscle. Materials and methods: This retrospective case-control study compared the self-reported frequency and localization of low back pain between subjects with normal (control group; n=31; mean age 62.5y) and markedly tortuous (study group; n=31; mean age 63.2y) iliac arteries. The groups consisted of 17 male and 14 female age-matched pairs. All participants were outpatients aged 40 to 80 y having undergone abdominal computed tomography (CT) without significant abnormalities. They completed a questionnaire on low back pain. Marked iliac tortuosity, defined as arterial bends of 90 deg. or sharper, was subdivided into bends targeting the psoas muscle and bends passing in front of or behind the psoas muscle. Results: Lateral low back pain on one or both sides was reported more often in the study group (n=14) than in the control group (n=6), p=0.031. Lateral low back pain was reported on 11 of 20 sides of a markedly tortuous iliac artery targeting the psoas muscle, but only on 8 of 62 sides in the control group, p=0.0003. In subjects with marked iliac tortuosity targeting the psoas muscle on one side, the side of targeting correlated with the side of pain, p=0.032. Conclusion: Iliac artery tortuosity targeting the psoas muscle is associated with ipsilateral low back pain. This association may explain low back pain in some of the cases currently regarded as nonspecific.