[Transplantation of collagen-chitosan nerve conduits filled with glial cell line-derived neurotrophic factor gene-modified schwann cells for the repair of sciatic nerve defect].

OBJECTIVE: To explore the effects of the transplantation of collagen-chitosan nerve scaffold containing glial cell line-derived neurotrophic factor(GDNF)gene modified schwann cells on the recovery of long-distance sciatic nerve defect. METHODS: The rat models of 8 mm long-distance sciatic nerve defect were established and divided into three groups, with 6 rats in each group. In GDNF-Sch group, the defect was repaired by GDNF modified Schwann cells combined with collagen-chitosan nerve scaffold. In Sch group, the defect was repaired by Schwann cells combined with collagen-chitosan nerve scaffold. In the control group, the defect was repaired by autologous nerve graft. Sciatic function index(SFI)was detected 3, 6, and 12 weeks after surgery. After 12 weeks, the tibialis anterior muscle wet weight, electrophysiology, and regenerated nerve morphology were detected. RESULTS: The SFI in the operated side significantly differed among these three groups after 6 and 12 weeks(P<0.05). Along with prolonged treatment, the GDNF-Sch group had similar SFI recovery with the control group but significantly better SFI recovery than Sch group. After 12 weeks, the sensory nerve conduction velocity in the GDNF-Sch and Sch group was not significantly different(P>0.05)but was significantly lower than that in the control group(P<0.05). Both the GDNF-Sch group and Sch group had significantly lower sensory nerve amplitude comparing with the control group(P<0.05), whereas that in the GDNF-Sch group was significantly higher than that in the Sch group(P<0.05). GDNF-Sch group and the control group had significantly higher motor nerve conduction velocity and amplitude than Sch group(P<0.05), while no such statistically significant difference was seen between the two groups(P >0.05). After 12 weeks, the wet weight of the bridging side of the tibial muscle in the control group, Sch group, and GDNF-Sch group was(0.360±0.020), (0.250±0.018), and(0.310±0.025)g, which were significantly lower than the control side [(0.440±0.031), (0.420±0.024), and(0.430±0.027)g, respectively(P<0.05)]. Muscle wet weight in bridge side of GDNF-Sch group and the control group were significantly higher than in Sch group(P<0.05), but it was not significantly different between the GDNF-Sch group and the control group(P>0.05). CONCLUSION: Transplantation of collagen-chitosan nerve scaffold containing GDNF gene modified Schwann cells can remarkably facilitate sciatic nerve defect recovery, with a milimar effectiveness as autologous nerve grafting.

In vitro and in vivo biocompatibility investigation of diamond-like carbon coated nickel-titanium shape memory alloy.

OBJECTIVE: To investigate the biocompatibility of diamond-like carbon (DLC) coated nickel-titanium shape memory alloy (NiTi SMA) in vitro and in vivo. METHODS: The in vitro study was carried out by co-culturing the DLC coated and uncoated NiTi SMA with bone marrow mesenchymal stem cells (MSCs), respectively, and the in vivo study was carried out by fixing the rabbits' femoral fracture model by DLC coated and uncoated NiTi SMA embracing fixator for 4 weeks, respectively. The concentration of the cells, alkaline phosphatase (AKP), and nickel ion in culture media were detected, respectively, at the first to fifth day after co-culturing. The inorganic substance, osteocalcin, alkaline phosphatase (ALP), and tumor necrosis factor (TNF) in callus surrounding fracture and the Ni(+) in muscles surrounding fracture site, liver and brain were detected 4 weeks postoperatively. RESULTS: The in vitro study showed that the proliferation of MSCs and the expression of AKP in the DLC-coated group were higher than the uncoated group (P < 0.05), while the uncoated group released more Ni(2+) into the culture media than that in the coated group (P < 0.05). The in vivo study revealed that the inorganic substance and AKP, osteocalcin, and TNF expression were significantly higher in the DLC coated NiTi SMA embracing fixator than that in the uncoated group (P < 0.05). Ni(2+) in liver, brain, and muscles surrounding the fracture were significantly lower in the DLC coated groups than that in the uncoated group (P < 0.05). CONCLUSION: Nickel-titanium shape memory alloy coated by diamond-like carbon appears to have better biocompatibility in vitro and in vivo compared to the uncoated one.

Nervus cutaneus femoris posterior pedicle flap for repairing large soft tissue defects at the heel or inferior segment of the shank.

OBJECTIVE: To investigate the clinical effect of the nervus cutaneus femoris posterior pedicle flap on repairing large soft tissue defects at the heel or inferior segment of the shank. METHODS: Totally 14 cases were followed up for 8-22 months (mean 15.5 months) to observe the clinical effects of nervus cutaneus femoris posterior pedicle flap on repairing large soft tissue defects of the heel or inferior segment of the shank. Among them, there were 3 patients afflicted with infection and cutaneous defects in the middle and inferior segment of the shank after internal fixation of open fracture, 4 patients with soft tissue defects of the ankle and uncovered tendo calcaneus, and 7 patients with soft tissue defects of the heel and exposed calcaneus. RESULTS: The flaps survived well in 13 cases and partial necrosis occurred in 1 case that was thereafter cured with changing dressing. Various extents of pain and stiffness of the knee joints were present in all cases and disappeared through 1-8 weeks' (mean 3.2 weeks) functional exercises. The last follow-up showed that all the flaps kept good texture and satisfactory appearance. CONCLUSIONS: The nervus cutaneus femoris posterior pedicle flap, having the advantages of simple surgical procedures, anastomosing the nerves and restoring the sensation of recipient site, can be used for recovering large soft tissue defects of the shank and ankle.

[Strategy of the treatment for dislocation of cervical vertebra].

OBJECTIVE: To study the strategy of the treatment for dislocation of cervical vertebra. METHODS: The clinical data of 39 cases with dislocation of cervical vertebra were analyzed. Among them,29 were male and 10 were female. The average age was 40 years old (range from 6 to 74 years old). Segment of dislocation: 15 cases in C(1,2), 1 case in C(3,4), 9 cases in C(4,5), 9 cases in C(5,6), 5 cases in C(6,7). Spinal injury according to Frankel grade, 9 cases were A grade,8 were B, 5 were C, 8 were D, 8 were E, 1 case had radicular symptom. Thirty-two cases were early and rapidly treated with traction (progressive weight). Seventeen cases were treated with operation. RESULTS: Traction-reduction was successful in 90% of patients. According to Frankel grade, 32 cases averagely improved 0.63 grades. Six cases of severe spinal injury accompany with interlocking of zygopophysis died. CONCLUSION: Inspecting weight of traction is important in rapid traction-reduction for dislocation of cervical vertebra. The choice of surgical treatment depends on the degree of reduction, the result of MRI,the grade of spinal trauma and the status of patients.