ObjectiveTo study the effect of the loaded concentration gradient of nerve growth factor (NGF) immobilized conduit on rat peripheral nerve defect repair. MethodsThe peripheral nerve conduits made of poly (ε-caprolactone)-block-poly (L-lactide-co-ε-caprolactone) were prepared with uniform loads or concentration gradient loads by combining differential absorption of NGF/silk fibroin (SF) coating, and the gradient of NGF was immobilized in the nerve conduits. ELISA method was used to exam the NGF release for 12 weeks in vitro. Twenty-four male Sprague Dawley rats (weighing, 220-250 g) were selected to establish the right sciatic nerve defect model (14 mm in length) and randomly divided into 4 groups according to repair methods. The transected nerve was bridged by a blank conduit without NGF in group A, by a conduit containing uniform loads of NGF in group B, by a conduit concentration gradient loads of NGF in group C, and by the autogenous nerve segment in group D. The gross observation, electrophysiological examination, histological observation, and transmission electron microscope observation were carried out to assess the nerve regeneration at 12 weeks after surgery. ResultsThe cumulative release amount of NGF was (14.2±1.4) ng/mg and (13.7±1.3) ng/mg in gradient of NGF loaded conduits and uniform NGF loaded conduits respectively at 12 weeks, showing no significant difference (t=0.564, P=0.570). All the animals survived to completion of the experiment; plantar ulcers occurred at 4 days, which healed at 12 weeks; groups C and D were better than groups A and B in ulcerative healing. At 12 weeks after surgery, the compound muscle action potential of group A was significantly lower than that of groups B, C, and D (P<0.05), and group B was significantly lower than groups C and D (P<0.05), but no significant difference was found between groups C and D (P>0.05). The axon density of group C was significantly higher that of groups A, B, and D (P<0.05); group D was significantly higher than groups A, B, and C, and group C was significantly higher than groups A and B in the axon number, axon diameter, and area of muscle fiber (P<0.05); the thickness of myelin sheath of groups C and D was significantly larger than that of groups A and B (P<0.05), but no significant difference was found between groups C and D (P>0.05). ConclusionGradient of NGF loaded nerve condnits for rat sciatic nerve defect has similar results to autogenous nerve, with a good bridge, which can promote the sciatic nerve regeneration, improve the myelinization of the regenerating nerve, and accelerate the function reconstruction of the regenerating nerve.
ObjectiveTo investigate the effectiveness of mini titanium plate for the treatment of intracapsular condylar fractures-type A. MethodsBetween March 2013 and July 2015, 22 cases (26 sides) of intracapsular condylar fractures-type A were treated with mini titanium plate through anterior auricular approach. There were 13 males and 9 females, aged from 16 to 32 years (mean, 22.7 years). The disease causes were traffic accident injury in 17 cases, falling injury in 4 cases, and heavy impact injury in 1 case. Five cases had intracapsular condylar fractures-type A only, and the other cases were accompanied with fractures of mandible, maxillary, or other part of jaw. All patients had different degrees of limitation of opening mouth, occlusal disorder, and joint pain, and the maximum opening was 5-16 mm (mean, 8.6 mm). All patients received surgical treatment within 2 to 9 days after injury (mean, 4 days). The clinical dysfunction index (DI) of Helkimo index was used to evaluate the mandibular motor function postoperatively. According to the 4 basic criterion of cure about mandibular condylar fractures by the international consensus conference in 1999, and maximal mouth opening by HE Dongmei et al., the surgical treatment effectiveness was evaluated. ResultsAll wounds healed at stage I, with no infection or other complications. All 22 cases were followed up 5-8 months (mean, 6 months). At 1 week after operation, the coronal spiral CT and three-dimensional reconstruction showed that contraposition of fractures was good, and the condyles located in the articular fossa. At 6 months after operation, the maximum opening was 33-42 mm (mean, 35.7 mm). After operation, 3 cases showed the mandible deflected to the affected side when opening, and limited lateral motion. According to the DI evaluation method in Helkimo index, there were 7 sides of DI grade 0, 18 sides of DI grade I, and 1 side of DI grade II. Based on surgical treatment effect of intracapsular condylar fractures-type A, occlusion recovery was obtained in 19 cases (86.36%), maximum opening degree of≥35 mm in 20 cases (90.91%), no symptoms of joint injury in 19 cases (86.36%), and no serious postoperative complications in 22 cases (100%); 17 cases (77.27%) were in accordance with the above 4 items. ConclusionMini titanium plate is one of the most effective approaches to treat intracapsular condylar fractures-type A.