A 39-year-old man presented with an 8-month history of bilateral lower limb weakness that was more severe on the left side. Two months later, the patient developed numbness in the left limb and blurred vision in the right eye. He had difficulty with fine motor actions and prickling paresthesia of his left arm and hands. His symptoms were progressive. In addition, he noticed that in his lower limbs, he had a sensation of stepping on cotton that lasted for several months. His physical examination revealed that the muscle strength in his left limb was grade Ⅳ, the muscle tension in his limbs was normal. The bilateral Hoffman sign was (+), and tendon reflexes in the upper limbs were (++). Bilateral knee reflexes and ankle reflexes were (+++). There was prickling paresthesia in the left limbs, his deep sensation was normal. Bilateral Babinski sign, Chaddock sign, and meningeal stimulation sign were (-), and his Japanese Orthopedic Association (JOA) score was 10. Cervical MRI revealed a mild cervical disc herniation at C5–C6 and an area of atypically enlarged intramedullary high signal intensityextending from C4–C7 (T2-weighted) with contrast enhancement at C5–C6 (T1-weighted).(Fig. 1). Electromyography indicated that the incubation period on the right side of the visual evoked potential (VEP) was longer than that on the left side, and the wave amplitude was lower. The amplitude of P40 on the right side of the somatosensory evoked potential (SEP) was lower than that on the opposite side.Lumbar puncture was performed to assess the cerebrospinal fluid (CSF) and revealed that the CSF pressure was approximately 160 mmH2O. Oligoclonal band electrophoresis of the CSF was (-), and no microorganisms were identified. The glucose and protein content on biochemical analysis of the CSF were slightly increased. The patient underwent a tortuous process of diagnosis and treatment. He was admitted to the department of neurology and was initially diagnosed with acute myelitis based on CSF examination and electromyography. After a month of glucocorticoid shock therapy, the patient's symptoms did not improve significantly but worsened, and bilateral femoral head necrosis occurred after 3 months. Then, the patient underwent spinal surgery, and a sagittal T2-weighted MRI scan revealed high signal intensity from C4 to C7. The range and intensity of the edema signal increased.Gadolinium (Gd)-enhanced sagittal T1-weighted MRI demonstrated a mild but well-circumscribed contrast-enhanced intramedullary focus at the level of C5–C6. On conventional radiography, kyphosis was observed at C3–C6, but no signs of instability were present. (Fig. 2) Careful inquiry of the patient’s medical history revealed that the patient had a history of a minor cervical sprain 1 month before the onset of symptoms. Can mild cervical disc herniation cause extensive spinal cord edema and contrast enhancement? We do not have much experience.
After sufficient communication with the patient and his family, we performed single-stage C5/6 anterior cervical discectomy and fusion (ACDF). The patient’s postoperative course was uncomplicated, and he had an immediate but partial improvement in his symptoms. During follow-up at 3 months after surgery, MRI showed that the spinal cord was fully decompressed, and the edema signal intensity had not weakened, but the range was reduced. The functional result according to the modified JOA score improved from 10 to 13 within 3 months. (Fig. 3) A repeat MRI scan performed 1 year after surgery showed that the signal intensity and range of edema were further reduced, and the patient’s clinical symptoms were further improved. (Fig. 4) Two years after surgery, the patient's MRI scan showed that the T2-weighted edema signal had disappeared completely, and only slight abnormal signal remained on fat-saturated T2-weighted images. The numbness and weakness in his extremities has also improved, and his JOA score was 16. (Fig. 5)