RESUMEN
Although neurocircuits can be activated by focused ultrasound stimulation, it is unclear whether this is also true for spinal cord neurocircuits. In this study, we used low-intensity focused ultrasound (LIFU) to stimulate lumbar 4-lumbar 5 (L4-L5) segments of the spinal cord of normal Sprague Dawley rats with a clapper. The activation of the spinal cord neurocircuits enhanced soleus muscle contraction as measured by electromyography (EMG). Neuronal activation and injury were assessed by EMG, western blotting (WB), immunofluorescence, hematoxylin and eosin (H&E) staining, Nissl staining, enzyme-linked immunosorbent assay (ELISA), immunohistochemistry (IHC), somatosensory evoked potentials (SEPs), motor evoked potentials (MEPs), and the Basso-Beattie-Bresnahan locomotor rating scale. When the LIFU intensity was more than 0.5 MPa, LIFU stimulation induced soleus muscle contraction and increased the EMG amplitudes (P < 0.05) and the number of c-fos- and GAD65-positive cells (P < 0.05). When the LIFU intensity was 3.0 MPa, the LIFU stimulation led to spinal cord damage and decreased SEP amplitudes for electrophysiological assessment (P < 0.05); this resulted in coagulation necrosis, structural destruction, neuronal loss in the dorsal horn by H&E and Nissl staining, and increased expression of GFAP, IL-1ß, TNF-α, and caspase-3 by IHC, ELISA, and WB (P < 0.05). These results show that LIFU can activate spinal cord neurocircuits and that LIFU stimulation with an irradiation intensity ≤1.5 MPa is a safe neurostimulation method for the spinal cord.
RESUMEN
RATIONALE: Nocardial spinal epidural abscess is rare. The diagnosis is often difficult to make and, if delayed, poses a high risk of long-term disability. Nocardial spinal epidural abscess with severe lumbar disc herniation has not previously been reported. PATIENT CONCERNS: A 50-year-old man presented with progressive lumbago and leg pain for 6 weeks after receiving acupuncture therapy, and then the patient suddenly occurred urine retention after walking. DIAGNOSES: Clinical examination revealed sign of cauda equina syndrome. Magnetic resonance imaging (MRI) revealed a Lumbar(L)4 to L5 disc herniation, L3 to Sacrum(S)1 epidural abscess, and L2 to S1 paravertebral abscess. The causative organism was Nocardia farcinica. INTERVENTIONS: An urgent paravertebral abscess debridement and right L4 to L5 laminectomy were performed. Simultaneously, the disc tissue protruding into the spinal canal was removed, as well as irrigation and drainage. And antimicrobial treatment was continued for 12 months. OUTCOMES: Fortunately, the patient was able to walk with a cane and urinate autonomously without a catheter, although this remained difficult 7 days after surgery. After 1 year of treatment, the patient has recovered completely and returned to work. LESSONS: Nocardial spinal epidural abscess with severe lumbar disc herniation is extremely rare. Pain from spinal degenerative diseases often masks the early symptoms of spinal infection. It's worth noting that invasive treatment of spine is a way of causing spinal nocardial infection.