RESUMO
Objective To propose a two-way fluid-structure interaction (FSI) method based on real patients with carotid artery stenosis, and analyze the hemodynamic parameters of carotid plaques with different types at the lesion as well as deformation and stress changes of the plaque itself. Methods Three-dimensional ( 3D) modeling was performed based on computed tomography angiography ( CTA) data of patients with moderate carotid artery stenosis. The carotid artery wall model and plaque model were separated, and transient fluid structure coupling calculation was performed. The situation from early stage of carotid atherosclerosis to formation of the plaque was simulated. The plaque types were divided into thickened plaques, lipid plaques, mixed plaques and calcified plaques, among which thickened plaques were regarded as non-plaque conditions for representing the thickening of vascular intima-media. The stenotic carotid arteries with different plaque types were compared and analyzed. Results The plaques with different types had little effect on the overall blood flow, but the wall shear stress of lipid plaques at the lesion was lower than that of other plaques. With thickened plaques as a control, concurrence of the plaque would inhibit artery expansion, and lipid plaques were the most obvious. Calcified plaques had the highest average plaque structure stress, while lipid plaques had the lowest average plaque structure stress. Conclusions The method proposed in this study can analyze fluid area and solid area at the same time. The results can contribute to better understanding the influence of different plaque types on carotid artery diseases.
RESUMO
Objective To evaluate the method and clinical effect of subtalar joint distractor assisted open reduction and internal fixation of comminuted intra-articular calcaneal fracture.Methods Twenty-two patients with fresh closed calcaneal fracture treated with open reduction and internal fixation from May 2011 to July 2013 were included in the study.According to the modes of operation,the patients were randomly divided into two groups (n =11 in each):in group A patients underwent fracture reduction assisted by subtalar joint distractor and in group B patients underwent Steinmann pin traction and poking reduction.All were fixed using the lateral calcaneal plate.Operation time,B(o)hler angle,Gissanes angle,calcaneus height,incision healing time and complications of the two groups were investigated for evaluating the effect of operation.Clinical effect was evaluated using the American Orthopedic Foot & Ankle Society (AOFAS) score before the removal of internal fixation.Results Period of follow-up was (14.3±0.8)months (range,12 to 18 months).Two patients in group B had delayed wound healing,and were treated with regular wound care.At the final follow-up,no infection,nonunion,malunion and internal fixation failure were observed.B(o)hler angle,operation time and calcaneus height observed in group A were superior to those in group B (P ＜0.01).There was no significant difference in Gissanes angle between the two groups (P ＞ 0.05).Compared to the preoperative data,B(o)hler angle,Gissanes angle and calcaneus height were significantly improved in both groups (P ＜0.01).AOFAS score was (83.6 ± 1.4) points in group A and (81.7 ± 1.5) points in group B.Conclusion Subtalar joint distractor assisted open reduction and internal fixation is effective to shorten operation time,improve fracture reduction,reduce wound complications and increase the operative effect for comminuted intraarticular calcaneal fracture.
RESUMO
Objective To investigate the clinical efficacy of fixation of distal radius fracture with dorsal instability with locking compression plate (LCP) via radial approach.Methods From September 2009 to October 2012, 21 cases underwent LCP fixation of the distal radius fracture with dorsal instability via radial approach.The study included 14 males and 7 females (mean age, 54.5 years;range, 38-81 years).Twelve cases were injured in traffic accidents, 7 in falls and 2 in high falls.Fracture AO classification was type A3 in 10 cases, type C1 in 8 cases and type C2 in 3 cases.Two cases (one type A3 and one type C1) had malunion.When the lateral column, intermediate column, radial edge and dorsal plane were exposed by radial incision, LCP fixation with bone grafting was performed to restore the height of radial styloid process, ulnar deviation and palmar tilt.According to the GartlandWerley score, wrist joint function was evaluated.Results Mean duration of follow-up was 13.5 months (range, 12 to 24 months).Stage Ⅰ bone union was shown on X-rays, with the healing time of 7.5 weeks.Based on the X-rays at postoperative 6 months, 1 year and 2 years, the shortening of radial styloid process was ≤ 2 mm, mean volar tilt was 12.5°(range, 8°-17°) , mean ulnar tilt was 20.5° (range, 15°-26°), and step-off or gap of the articular surface was ≤ 2 mm.In postoperative wrist motion assay, mean volar flexion was 60°(range, 30°-70°), mean dorsal flexion was 55° (range, 30°-65°), mean radial deviation was 17°(range, 10°-20°), mean ulnar deviation was 25.5° (range, 20°-30°),pronation was 65.5° (range, 60°-70°) , and mean supination was 75.5° (range, 60°-80°).Mean grip strength was 75％ (60％-95％)of the contralateral side.Two cases suffered from pain (one complained of moderate pain and one minor pain occasionally).According to the Gartland-Werley score, 16 cases were rated excellent, 2 good, 2 fair and 1 poor, with the excellent rate of 86％.No complication was found as injury of the superficial branch of radial nerve, infection, nonunion, nail loosening, medium neuritis and tendon injury.Conclusions Lateral column, intermediate column, radial edge and dorsal plane can be shown via the radial approach.LCP fixation combined with bone grafting contributes to fracture anatomical reduction.