Urine-derived stem cells are a kind of cells with strong proliferative ability and multi-directional differentiation characteristics of mesenchymal stem cells isolated from urine. Urine-derived stem cells are derived from the kidney and express mesenchymal stem cell-specific antigens; experimental studies have shown that they can differentiate into a variety of cells such as adipocytes, chondrocytes, bone cells, nerve cells, etc., and have the function of promoting tissue repair. A review of the research progress of urinary stem cells is now available.
Objective To discuss the improved method and effectiveness of posterior pedicle-screw fixation combined with restoring and grafting through the injured vertebrae for treating thoracolumbar burst fracture. Methods Between March 2008 and September 2010, 21 patients with thoracolumbar burst fracture were treated by posterior pedicle-screw fixationcombined with restoring and grafting through the injured vertebrae. Of 21 cases, 15 were male and 6 were female with an age range of 20-61 years (mean, 38.4 years). Affected segments included T12 in 5 cases, L1 in 7 cases, L2 in 5 cases, and T12-L1 in 4 cases. According to Frankel classification for neurological function, 2 cases were rated as grade A, 4 cases as grade B, 6 cases as grade C, 5 cases as grade D, and 4 cases as grade E; based on Denis classification, all 21 cases were burst fractures, including 7 cases of type A, 11 cases of type B, and 3 cases of type C. The X-ray film was taken to measure the relative height of fractured vertebrae and Cobb’s angle, and the function of the spinal cord was evaluated at preoperation, postoperation, and last followup. Results All the incisions healed primarily. The 21 patients were followed up 12-30 months (mean, 26 months). No loosening or breakage of screws and rods occurred. X-ray films showed good bone heal ing with the heal ing time from 12 to 23 months (mean, 16 months). The Cobb’s angles at 1 week and 1 year postoperatively were (3.4 ± 2.4)° and (5.2 ± 3.2)° respectively, showing significant differences when compared with preoperative angle (22.1 ± 1.2)° (P lt; 0.05), while no significant difference between 1 week and 1 year after operation (P gt; 0.05). The anterior height of injured vertebrae recovered from (14.6 ± 2.1) mm (40.2% ± 1.5% of the normal) at preoperation to (36.0 ± 2.0) mm (95.3% ± 1.3% of the normal) at 1 week, and to (35.0 ± 2.4) mm (94.4% ± 2.5% of the normal) at 1 year; significant differences were found between preoperation and postoperation (P lt; 0.05), while no significant difference between 1 week and 1 year after operation (P gt; 0.05). At 1 year after operation, the Frankel neurological function grade was improved in varying degrees, showing significant difference when compared with preoperative grade (χ2=11.140, P=0.025). Conclusion Improved method of posterior pedicle-screw fixation combined with restoring and grafting through the injured vertebrae in treatment of thoracolumbar burst fracture can reconstructthe anterior and middle column stabil ity and prevent loss of Cobb’s angle and height of vertebrae.