Magnetic resonance imaging undetectable epiduroscopic hotspot in chronic discogenic back pain- Does sinuvertebral neuropathy actually exists?

BACKGROUND: The causes of chronic diskogenic back pain have not yet been clearly identified. Neural ingrowth around the annulus is widely considered to be one of the possible cause. However, neuropathy around the annulus has yet to be observed visually. We report a case of a hotspot that was observed in an epiduroscopic view, but not in imaging findings. CASE DESCRIPTION: A 46-year-old woman was admitted with pain in the back, left buttock, and posterior thigh for 2 years. A straight leg raising test was positive on the left side, and left great toe dorsiflexion was decreased to grade 3/5. The Visual Analog Scale pain score was 7/10. On the basis of her symptoms, epidural block, medial branch block, sacroiliac joint block, piriformis muscle injection, physical therapy, and medication were attempted, but no improvement in symptoms was observed. A provocation test was performed at the L3-L4, L4-L5, and L5-S1 intervertebral disks, and severe pain was induced in the L5-S1 intervertebral disk, which was not suspicious on magnetic resonance imaging. We performed transforaminal epiduroscopic laser ablation on L5-S1 and found a hotspot on L5-S1 during the procedure. During laser provocation of the hotspot, the patient complained of severe pain in her lower back and legs, and her pain decreased after ablation of hotspot with laser and improvement in motor weakness was noticed. CONCLUSION: In this study, we observed annulus hotspots, which have not been observed in imaging studies such as computed tomography or magnetic resonance imaging in patients with chronic back pain and leg pain, and observed remarkable symptom improvement after transforaminal epiduroscopic laser ablation.