ULTRASOUND TRIAD FOR SUPERIOR CLUNEAL NERVE PAIN

G. Iudicelli | Università di Roma “La Sapienza, Rome, Italy

Background and Aims. SCN entrapment is an underrecognized cLBP cause. As direct imaging is limited, US surrogate markers of the biomechanical environment are crucial. We analyzed triad prevalence and correlation with pain intensity.
Methods. In this single-center, cross-sectional observational pilot study, we enrolled 12 patients with cLBP (>12 weeks) localized to the SCN distribution and a healthy control group (12). Ultrasound measurements included TLF thickness in longitudinal and transverse planes, TLF convexity loss, iliac crest enthesophytes, and CN. Statistical analyses comprised the Mann-Whitney U test, Fisher exact test, Spearman rank correlation, and multivariate logistic regression. Significance was set at p < 0.05.
Results. The ultrasound marker triad (CN, iliac enthesophytes, and TLF thickening > 3 mm) demonstrated high diagnostic specificity: individually, CN were present in 91.7% of patients vs. 8.3% of controls (p = 0.001), iliac enthesophytes in 58.3% vs. 0% (p = 0.005), TLF thickening > 3 mm in 41.7% of patients vs. 0% of controls (p = 0.001), and TLF convexity loss in 100% vs. 75% (p = 0.03). Mean TLF thickness was significantly greater in patients—3.53 ± 0.46 mm longitudinally and 3.42 ± 0.39 mm transversely—compared with controls (2.61 ± 0.28 mm and 2.50 ± 0.32 mm; both p < 0.001). TLF thickness correlated strongly with NPRS (Spearman rho = 0.825; p = 0.001) but not with DN4. Logistic regression demonstrated that the marker triad accounted for 67% of NPRS variance (R² = 0.67).
Conclusions. US surrogate markers identify pathological SCN environments. Strong nociceptive pain correlation suggests fascial-muscular biomechanics over direct nerve damage. This non-invasive protocol informs targeted rehab.