A 49-year-old man presented with a history of having undergone acupuncture treatment at another institution. During the acupuncture, he had experienced sudden, acute back pain that radiated into his left leg. The severe back pain continued for about a month following the acupuncture treatment, whereupon he concluded that the acupuncture had probably harmed his back. He then consulted our hospital.
After admission, he continued to complain of back and left leg pain. Physical examination revealed a positive Lasegue sign (45°+) in the left lower limb. Neurological examination of both legs was normal, and urinary function was normal. There were no needle marks or signs of a skin infection in the lower back area. His medical history showed no other pathological conditions, and he had been taking no anticoagulant medicine recently. Laboratory findings (routine blood tests, blood biochemistry evaluations, blood clotting function tests) were within the normal range. Because he had been treated at another hospital, the needle size and the depth of needle insertion were unknown.
His MRI results after admission showed an intraspinal mass at L5/S1. The mass, which was oval, showed T2 isointensity and T1 hyperintensity. On MRI, it resembled an intraspinal synovial cyst. We thought the mass was probably a ligamentum flavum cyst or a facet joint cyst because it was attached to the facet joint on the left side of the spinal canal (Fig. 1).
Thus, with the possible diagnosis of an intraspinal cyst compressing the right S1 nerve root, we performed a laminectomy to relieve the patient’s low back pain, for which analgesic treatment was ineffective. Removal of the L5 left inferior margin plate clearly exposed the mass, which proved to be a blood clot surrounded by epidural fat with no capsule. It did not contain any jelly-like material, there was no calcification around the rim, and the nerve root and dura mater were intact. Thus, an epidural hematoma was diagnosed. The surgery went smoothly and was completed in less than 1 h. His symptoms were immediately relieved by the surgery, and he showed good function at the final follow-up visit in April 2020.