ABSTRACT
BACKGROUND: Methylene blue is used as a developer to identify intervertebral disc degeneration in the transforaminal endoscopic surgery. However, many scholars have indicated that methylene blue can accelerate the degeneration process, whilst foreign researches have reported that it may play therapeutic effect on degenerative intervertebral discs under acidic conditions due to its acidophily. Therefore, whether methylene blue holds toxic effect on the disc remains controversial. OBJECTIVE: To determine whether methylene blue exerts toxic effect on nucleus pulposus cells by cell counting-kit 8 (CCK-8) assay. METHODS: The discarded nucleus pulposus from two patients with intervertebral disc herniation were selected. After digestion, nucleus pulposus cells were extracted and cultured until proliferated to 80% of the medium. Then, the cells were digested to make cell suspensions, divided into six groups and inoculated into the 96-well plates: blank control (only the medium, CCK-8 solution), control group (only medium, cells and CCK-8 solution), and the other groups were cultured with 1%, 2%, 3%, and 4% methylene blue, respectively. The absorbance values were measured by CCK-8 assay at 24, 48, 72 and 96 hours after incubation to calculate the cell viability, and the color change was observed. RESULTS AND CONCLUSION: The color in the control group was the deepest, and the color became lighter with the concentration of methylene blue increasing. The cell viability was the highest in the control group, and it was decreased with the concentration of methylene blue increasing. Thus, methylene blue may exert toxic effect on human nucleus pulposus cells.
ABSTRACT
<p><b>OBJECTIVE</b>To study clinical effects of short-segment fixation and injured vertebra bone grafting through injured pedicle for the treatment of thoracolumbar burst fractures under MAST Quadrant retractor via a paraspinal muscle approach.</p><p><b>METHODS</b>The data of 42 patients with thoracolumbar burst fractures treated from June 2009 to September 2012 were reviewed. There were 19 males and 23 females, with an average age of (55.2±11.9) years old. The mean injury time was (5.8±4.3) days. Fracture segments included T10 in 3 cases, T11 in 6 cases, T12 in 13 cases, L1 in 9 cases, L2 in 7 cases, and L3 in 4 cases. According to Denis classification, 9 patients were type A, 21 patients were type B, 5 patiens were type C, 5 patients were type D, and 2 patients were type E. All the patients were treated with short-segment pedicle screw-rod system fixation under MAST Quadrant via the paraspinal muscle approach. The operative time, blood loss, complications and the height of vertebra, kyphosis Cobb angle, VAS scores, JOA scores were measured before and after treatment.</p><p><b>RESULTS</b>After treatment, the vertebral height and kyphosis Cobb angle were restored. Compared with preoperative results, postoperative vertebral height and kyphosis Cobb angle, VAS scores and JOA scores were all improved. But there was no statistically significance in vertebral height, kyphosis Cobb angle between postoperative at 1 week and 1 year.</p><p><b>CONCLUSION</b>Internal fixation combined with injured vertebra bone grafting through the injured pedicle for the treatment of thoracolumbar burst fractures via the paraspinal intermuscular approach under MAST Quadrant is a safe, minimally invasive, effective and satisfactory method.</p>