[The correlation analysis of balloon volume and bone cement volume in percutaneous kyphoplasty].

OBJECTIVE: To analyze the percutaneous kyphoplasty (PKP) data statistically to predict the bone cement volume (CV). METHODS: Retrospective analysis of 93 patients with 154 vertebrae of osteoporotic vertebra compressed fracture, who received PKP from January 2012 to December 2013 in Beijing Tian Tan Hospital, Capital Medical University. All procedures were bilateral and non-high-pressure polymethyl methacrylate injection. The balloon volume (BV), balloon peak pressure (Pmax), CV and the ratio of Pmax to BV (P/BV) were documented. The data was analyzed by correlation analysis and linear regression analysis to reveal the correlation between BV and CV. RESULTS: Seven vertebrae had bone cement leakage, no intraspinal leakage, no neuro-deficit. Visual analogue scale was 0-2 of all patients on 3 d postoperation. The data of 147 vertebrae without leakage: BV was 2.1-6.3 ml, Pmax was 130-359 psi, CV was 2.8-8.5 ml, and the ratio of Pmax to BV (P/BV) was 25-263 psi/ml. The data analysis showed there was no high correlation between BV and CV as one group (R<0.75). However if divided the data into three groups by the value of P/BV, group A (P/BV<100), group B (100≤P/BV<200), group C (P/BV≥200), there was high correlation and linear relationship between BV and CV in each group (R>0.75, P<0.01). CV was 0.9-1.1 times of BV in group A; CV was 1.4-1.6 times of BV in group B; and CV was 2.0-2.2 times of BV in group C. CONCLUSION: CV is predictable by the BV and the ratio of Pmax to BV. It can reduce the rate of the leakage, and also can prevent the unsatisfactory results by insufficient bone cement volume.

[Effect of folic acid coated-crosslinked urethane-doped polyester elastomer nerve conduit on promoting the repair of long distance peripheral nerve injury in rats].

Objective: To investigate the effect of folic acid coated-crosslinked urethane-doped polyester elastomer (fCUPE) nerve conduit in repairing long distance peripheral nerve injury. Methods: Thirty-six 3-month-old male Sprague Dawley rats weighing 180-220 g were randomly assigned to 3 groups, each consisting of 12 rats: CUPE nerve conduit transplantation group (group A), fCUPE nerve conduit transplantation group (group B), and autologous nerve transplantation group (group C), the contralateral healthy limb of group C served as the control group (group D). A 20-mm-long sciatic nerve defect model was established in rats, and corresponding materials were used to repair the nerve defect according to the group. The sciatic function index (SFI) of groups A-C was calculated using the Bain formula at 1, 2, and 3 months after operation. The nerve conduction velocity (NCV) of the affected side in groups A-D was assessed using neuroelectrophysiological techniques. At 3 months after operation, the regenerated nerve tissue was collected from groups A-C for S-100 immunohistochemical staining and Schwann cell count in groups A and B to compare the level of nerve repair and regeneration in each group. Results: At 3 months after operation, the nerve conduits in all groups partially degraded. There was no significant adhesion between the nerve and the conduit and the surrounding tissues, the conduit was well connected with the distal and proximal nerves, and the nerve-like tissues in the conduit could be observed when the nerve conduit stents were cut off. SFI in group A was significantly higher than that in group C at each time point after operation and was significantly higher than that in group B at 2 and 3 months after operation ( P<0.05). There was no significant difference in SFI between groups B and C at each time point after operation ( P>0.05). NCV in group A was significantly slower than that in the other 3 groups at each time point after operation ( P<0.05). The NCV of groups B and C were slower than that of group D, but the difference was significant only at 1 month after operation ( P<0.05). There was no significant difference between groups B and C at each time point after operation ( P>0.05). Immunohistochemical staining showed that the nerve tissue of group A had an abnormal cavo-like structure, light tissue staining, and many non-Schwann cells. In group B, a large quantity of normal neural structures was observed, the staining was deeper than that in group A, and the distribution of dedifferentiated Schwann cells was obvious. In group C, the nerve bundles were arranged neatly, and the tissue staining was the deepest. The number of Schwann cells in group B was (727.50±57.60) cells/mm 2, which was significantly more than that in group A [(298.33±153.12) cells/mm 2] ( t=6.139, P<0.001). Conclusion: The fCUPE nerve conduit is effective in repairing long-distance sciatic nerve defects and is comparable to autologous nerve grafts. It has the potential to be used as a substitute material for peripheral nerve defect transplantation.

The critical chemical and mechanical regulation of folic acid on neural engineering.

The mandate of folic acid supplementation in grained products has reduced the occurrence of neural tube defects by one third in the U.S since its introduction by the Food and Drug Administration in 1998. However, the advantages and possible mechanisms of action of using folic acid for peripheral nerve engineering and neurological diseases still remain largely elusive. Herein, folic acid is described as an inexpensive and multifunctional niche component that modulates behaviors in different cells in the nervous system. The multiple benefits of modulation include: 1) generating chemotactic responses on glial cells, 2) inducing neurotrophin release, and 3) stimulating neuronal differentiation of a PC-12 cell system. For the first time, folic acid is also shown to enhance cellular force generation and global methylation in the PC-12 cells, thereby enabling both biomechanical and biochemical pathways to regulate neuron differentiation. These findings are evaluated in vivo for clinical translation. Our results suggest that folic acid-nerve guidance conduits may offer significant benefits as a low-cost, off-the-shelf product for reaching the functional recovery seen with autografts in large sciatic nerve defects. Consequently, folic acid holds great potential as a critical and convenient therapeutic intervention for neural engineering, regenerative medicine, medical prosthetics, and drug delivery.