Novel Screw Insertion Method for Anterior Surgical Treatment of Unstable Thoracolumbar Fracture: Quadrant Positioning Method.

OBJECTIVE: To develop a novel screw positioning method to improve the treatment of unstable thoracolumbar fractures. METHODS: A total of 72 patients with unstable thoracolumbar fractures who were treated with anterior screw-rod interfixation from January 2011 to October 2015 were included in this clinical study. Those patients included 48 male and 24 female patients with an average age of 45.10 years (range, 26-63 years). Patients were randomly divided into two groups: an observation group (n = 36) and a control group (n = 36). The quadrant positioning method was used for screw insertion in the observation group during the operation, while the traditional screw positioning method was used in the control group. The quadrant positioning method targeted four quadrants, including the superior anterior (SA), superior posterior (SP), inferior anterior (IA) and inferior posterior (IP) quadrants, while for the traditional screw positioning, four screws were inserted into the vertebral bodies above and below the excision. Patients were followed up for approximately 40 months to record recovery. Clinical and radiological records, local angle and fractured vertebra body height, clinical outcomes, complications, neurological improvement, and fusion rate were recorded and compared between the two groups. RESULTS: The quadrant positioning method was successfully used for anterior screw insertion. The quadrant center in the lateral view of the vertebral body was well marked, and screws were easily located on the scheduled quadrant. Blood loss (BL), hospital stay (HS), and operation time (OP) in the observation group were 749.40 ± 379.90 mL, 17.10 ± 4.10 days, and 167.40 ± 44.70 min, respectively. While those parameters in the control group were 1198.40 ± 339.27 mL, 23.22 ± 3.77 days, and 221.47 ± 32.15 min, respectively. The average operation time and hospital stay time were significantly shorter, and blood loss was significantly less in the observation group than in the control group (P < 0.05). Local angle and vertebral body height were markedly improved and 1-2 grade improvement was achieved in patients with neurological deficits in both groups. Both groups of patients achieved bony fusion during follow-up. No incision infection or internal fixation failure was observed in the two groups, and complications including cerebrospinal fluid and chylous leakage and hemothorax were resolved. CONCLUSIONS: The quadrant positioning method can shorten operation time, reduce blood loss, and accelerate postoperative recovery. The technique provides an effective method for screw insertion for double screw-rod instrumentation fixation in the treatment of thoracolumbar fracture via the anterior approach.

Effect of spinal cord extracts after spinal cord injury on proliferation of rat embryonic neural stem cells and Notch signal pathway in vitro.

OBJECTIVE: To investigate the effect of the spinal cord extracts (SCE) after spinal cord injuries (SCIs) on the proliferation of rat embryonic neural stem cells (NSCs) and the expressions of mRNA of Notch1 as well as of Hes1 in this process in vitro. METHODS: The experiment was conducted in 4 different mediums: NSCs+PBS (Group A-blank control group), NSCs+SCE with healthy SD rats (Group B-normal control group), NSCs+SCE with SD rats receiving sham-operation treatment (Group C-sham-operation group) and NSCs+ SCE with SCIs rats (Group D-paraplegic group). Proliferative abilities of 4 different groups were analyzed by MTT chromatometry after co-culture for 1, 2, 3, 4 and 5 d, respectively. The expressions of Notch1 and Hes1 mRNA were also detected with RT-PCR after co-culture for 24 and 48 h, respectively. RESULTS: After co-culture for 1, 2, 3, 4 and 5 d respectively, the MTT values of group D were significantly higher than those of group A, group B and group C (P<0.05). However, there were no significantly differences regarding MTT values between group A, group B and group C after co-culture for 1, 2, 3, 4 and 5 d, respectively (P>0.05). Both the expressions of Notch1 and Hes1 mRNA of group D were significantly higher than those of other 3 groups after co-culture for 24 h and 48 h as well (P<0.05). But there was no difference oin expressions of Notch1 and Hes1 mRNA among group A, group B and group C after co-culture for 24 h and 48 h (P>0.05). There was no difference in expressions of Notch1 and Hes1 mRNA between 24 h and 48 h treatment in group D. CONCLUSIONS: SCE could promote the proliferation of NSCs. It is demonstrated that the microenvironment of SCI may promote the proliferation of NSCs. Besides, SCE could increase the expression of Notch1 and Hes1 mRNA of NSC. It can be concluded that the Notch signaling pathway activation is one of the mechanisms that locally injured microenvironment contributes to the proliferation of ENSC after SCIs. This process may be performed by up-regulating the expressions of Notch1 and Hes1 gene.

[Determination of Levofloxacin by chemiluminescence method].

A novel chemiluminescence method for the determination of Levofloxacin is based on its enhancement effect on thereaction of luminol with H2O2. The calibration graph is linear over the range of 5.53 x 10(-11)-2.21 x 10(-8) mol x L(-1) and the detection limit is 1.38 x 10(-11) mol x L(-1). The relative standard deviation (RSD) is 2.56% (n = 9). The method has been successfully applied to the determination of Levofloxacin in capsule samples.