Objective To investigate the cl inical effect of Meek technique skin graft in treating exceptionally large area burns. Methods The cl inical data were retrospectively analysed from 10 cases of exceptionally large area burns treated with Meek technique skin graft from April 2009 to February 2010 (Meek group), and were compared with those from 10 casesof exceptionally large area burns treated with the particle skin with large sheet of skin allograft transplantation from January 2002 to December 2006 (particle skin group). In Meek group, there were 8 males and 2 females with an average age of 34.5 years (range, 5-55 years), including 6 cases of flame burns, 2 cases of hot l iquid burns, 1 case of electrical burn, and 1 case of hightemperature dust burn. The burn area was 82.6% ± 3.1% of total body surface area (TBSA). The most were deep II degree to III degree burns. The time from burn to hospital ization was (3.5 ± 1.3) hours. In particle skin group, there were 8 males and 2 females with an average age of 36.8 years (range, 18-62 years), including 5 cases of flame burns, 2 cases of hot l iquid burns, and 3 cases of gunpowder explosion injury. The burn area was 84.1% ± 7.4% of TBSA. The most were deep II degree to III degree burns. The time from burn to hospital ization was (4.9 ± 2.2) hours. There was no significant difference in general data between 2 groups (P gt; 0.05). Results The skin graft survival rate, the time of skin fusion, the systemic wound heal ing time, and the treatment cost of 1% of burn area were 91.23% ± 5.61%, (11.14 ± 2.12) days, (38.89 ± 10.36) days, and (5 113.28 ± 552.44) yuan in Meek group, respectively; and were 78.65% ± 12.29%, (18.37 ± 4.63）days, (48.73 ± 16.92) days, and (7 386.36 ± 867.64) yuan in particle skin group; showing significant differences between 2 groups (P lt; 0.05). Conclusion Meek technique skin graft has good effect in treating exceptionally large area burns with the advantages of high survival rate of skin graft, short time of skin fusion, and low treatment cost of 1% of burn area.
In order to find the most suitable algorithm of T-wave end point detection for clinical detection, we tested three methods, which are not just dependent on the threshold value of T-wave end point detection, i.e. wavelet method, cumulative point area method and trapezium area method, in PhysioNet QT database (20 records with 3 569 beats each). We analyzed and compared their detection performance. First, we used the wavelet method to locate the QRS complex and T-wave. Then we divided the T-wave into four morphologies, and we used the three algorithms mentioned above to detect T-wave end point. Finally, we proposed an adaptive selection T-wave end point detection algorithm based on T-wave morphology and tested it with experiments. The results showed that this adaptive selection method had better detection performance than that of the single T-wave end point detection algorithm. The sensitivity, positive predictive value and the average time errors were 98.93%, 99.11% and (-2.33±19.70) ms, respectively. Consequently, it can be concluded that the adaptive selection algorithm based on T-wave morphology improves the efficiency of T-wave end point detection.
ObjectiveTo discuss the influence of early postoperative hemodynamic, postoperative mortality and the incidence of adverse cardiovascular events with the phenomenon of prosthesis-patient mismatch. MethodsWe retrospectively analyzed the clinical data of 89 patients who had simple aortic valve replacement in our hospital bewteen January 2012 and January 2014. The 89 patients were divided into two groups including a match group (16 females and 48 males with average age of 58.1±10.4 years) and a mismatch group (15 females and 10 males with average age of 65.3±12.8 years). We compared early results between the two groups. ResultsThere is a statistic difference (P < 0.05) in aortic flow velocity, mean pressure gradient, and the maximum pressure gradient between the two groups. The survival rate of the match group is significantly lower than that of the mismatch group (P < 0.05). And there is a statistical difference in adverse cardiovascular event-free incidence between the two groups (P < 0.001). ConclusionThe phenomenon of prosthesis-patient mismatch can affect postoperative hemodynamic and lead to heart failure after surgery. And early mortality and the incidence of cardiovascular adverse events in patients are increased due to prosthesis-patient mismatch.
OBJECTIVE: To investigate the effect of subcutaneous tissue trimming on the survival skin area of avulsion skin flap. METHODS: Degloving injury was created in bilateral hind limbs of 7 pigs with avulsion injury machine, 4 cm x 10 cm avulsion skin flaps were elevated in degloving areas. Skin flaps in one side were replanted as control without any treatment. Subcutaneous tissue in the skin flaps of another side was partially excised and replanted by trimmed skin flaps. Survival skin flaps was calculated with computer at 7 days after operation. RESULTS: In the control group, the survival skin area was (40.41 +/- 9.23)%, while in the experimental group, the survival skin area was (60.90 +/- 15.26)%. There was significant difference between the two groups (P lt; 0.05). CONCLUSION: Trimming off subcutaneous tissue does improve the survival area of avulsion skin flap.
Valve transplantation is often used in the treatment of aortic valve insufficiency. However, after surgery, the reconstructed aortic roots have an expansion phenomenon, in which the lack of valve height causes the aortic valve to close again. In this paper, the effects of different aortic valve height design on valve opening and closing performance were studied. The optimal surgical plan was obtained by in vitro numerical simulation, providing technical support and theoretical basis. In this paper, six groups of three-dimensional geometric models with a valve height increment of ± 0.5 mm were established with a root diameter of 26.0 mm and a valve height of 14.0 mm. Through the structural mechanics calculation and analysis of the parameters such as maximum stress, valve area and contact force of the model, reasonable geometrical dimensions are obtained. The study found that the maximum stress values of the six groups of models ranged from 640 to 690 kPa, which was consistent with the results of the literature; the three-group models with valve heights of 13.5 mm, 14.0 mm, and 14.5 mm were within a reasonable range. The contact force value of the 6 groups of leaflets increased with the increase of valve height. Studies have shown that the height of the aortic valve has an effect on the aortic valve closure performance. A valve height that is too small or too large will reduce the aortic systolic valve area and affect the aortic function.
Objective To observe the changes of force bearing area and pressures of the rabbit tibiofemoral contact area and the biomechanical reconstruction level of joint after meniscal allograft. Methods A total of 28 Japanese rabbits were involved, weighing 3.0-3.5 kg, male or female. Of 28 rabbits, 7 were selected as meniscus donors, the remaining 21 rabbits were randomized into group A (n=7), group B (n=7), and group C (n=7). Group A underwent single knee opening and suturing, group B underwent medial meniscus excision and suturing, and group C underwent medial meniscus allograft after medial meniscus excision and suturing. The rabbits were sacrified at 12 weeks after operation for biomechanical observation through biomechanical machine and color imaging system. The meniscus tissue specimens were harvested from groups A and C to perform histological and immunohistochemical staining. Results After operation, all rabbits in 3 groups survived to the end of experiment. There were significant differences in the force bearing area and pressures at 0-90° flexion between group B and groups A, C (P lt; 0.05) at 12 weeks, showing no significant difference between group A and group C (P gt; 0.05); and there were significant differences in the force bearing area and pressures at 120° flexion among 3 groups (P lt; 0.05). The histological observation showed that the number of cartilage cells and collagen fibers returned to normal in group C, and the immunohistochemical staining showed that transplanted meniscus of group C contained large amounts of collagen fibers consisting of collagen type I and collagen type II. After 12 weeks of operation, the collagen type I contents were 0.612 5 ± 0.059 8 in group A and 0.587 2 ± 0.063 9 in group C, showing no significant difference (t=0.765, P=0.465); the collagen type II contents were 0.772 4 ± 0.081 5 and 0.814 3 ± 0.051 7, respectively, showing no significant difference (t= —0.136, P=0.894). Conclusion The allograft of rabbit meniscus can significantly increase the force bearing area of the tibiofemoral contact area and reduce the average pressure. Therefore, biomechanically speaking, the meniscus allograft can protect the articular cartilage and reconstruct the biomechanical balance.
Objective To observe the baseline characteristics and visual outcomes after two years follow-up of exudative age-related macular degeneration (AMD) patients treated with ranibizumb. Methods Forty-four eyes of 44 patients with exudative AMD were enrolled into this retrospective study, 19 were men and 25 were women. The mean age was 78 years (range 64 – 92 years). All patients were underwent best corrected visual acuity (BCVA, Early Treatment of Diabetic Retinopathy Study), fundus color photography, fundus fluorescein angiography (FFA), indocyanine green angiography (ICGA) and optical coherence tomography (OCT). The mean BCVA was (50.36±14.43) letters, the mean central foveal thickness (CFT) was (291.95±82.19) μm, and the fluorescence leakage area of choroidal neovascularization (CNV) was (7.61±5.84) mm2. All patients received three initial intravitreous injection of ranibizumb (IVR) and were retreated with monthly IVR when needed. The mean follow up time was 25.6 months (range 24 – 29 months). On 1, 2, 3, 6, 12, 18 and 24 months after treatment, BCVA and OCT were repeated. On 3, 6, 12, 18 and 24 months after treatment, FFA and ICGA were repeated. The change of BCVA, CFT and fluorescence leakage area of CNV were observed. The association of baseline characteristics and two year visual outcomes were analyzed. Results On 1, 2, 3, 6, 12, 18 and 24 months after treatment, the BCVA were improved significantly (t= −1.89, −3.51, −4.61, −4.04, −5.77, −4.69;P＜0.05), the CFT were decreased significantly (t=1.51, 2.30, 3.40, 3.28, 3.54, 3.88, 3.73;P＜0.05). On 3, 6, 12, 18 and 24 months after treatment, the fluorescence leakage area of CNV were reduced significantly (t=2.12, 2.90, 3.51, 4.12, 4.06;P＜0.05). The lower baseline BCVA, the more improved after treatment. The BCVA improvement degree has a negative relationship with baseline BCVA and fluorescence leakage area of CNV (r=0.505, −0.550;P＜0.05), but no correlation with baseline CFT (r=0.210,P＞0.05). Conclusion Two year visual outcomes of exudative AMD patients treated with ranibizumb is negative correlated with baseline BCVA and fluorescence leakage area of CNV, but not correlated with baseline CFT.
Objective To investigate the risk factors of high peritoneal transport characteristics in patients with end-stage renal disease undergoing initial continuous ambulatory peritoneal dialysis. Method The clinical data of continuous ambulatory peritoneal dialysis patients who underwent initial peritoneal dialysis and catheterization in the Department of Nephrology, West China Hospital of Sichuan University from January 2011 to December 2017 and completed the peritoneal equilibration test were collected retrospectively. According to the ratio of dialysate to plasma ratio for creatinine at 4 hour [D/Pcr (4h)] in the standard peritoneal equilibration test, the patients were divided into 4 groups (low transport, low average transport, high average transport and high transport). Spearman correlation analysis was used to analyze the related factors of D/Pcr (4h). The risk factors of high peritoneal transport characteristics were analyzed by ordered multi classification logistic regression. Results A total of 647 patients were included. The average age of the patients was (45.85±14.03) years, and the average D/Pcr (4h) was 0.67±0.12. Among them, there were 89 cases (13.76%) in the high transport group, 280 cases (43.28%) in the high average transport group, 234 cases (36.17%) in the low average transport group and 44 cases (6.80%) in the low transport group. Diabetic patients with D/Pcr (4h) were higher than those without diabetes mellitus (0.72±0.12 vs. 0.66±0.12; t=−4.005, P<0.001). Correlation analysis showed that age and 24-h urine volume were positively correlated with D/Pcr (4h); serum albumin, triglyceride, potassium, calcium, magnesium, phosphorus, hemoglobin, serum uric acid and creatinine were negatively correlated with D/Pcr (4h); body surface area (BSA), high sensitivity C-reactive protein, ferritin, cholesterol, sodium, intact parathyroid hormone and estimated giomerular filtration rate had no correlation with D/Pcr (4h). Regression analysis showed that serum albumin [odds ratio (OR)=0.842, 95% confidence interval (CI) (0.809, 0.877), P<0.001], serum uric acid [OR=0.996, 95%CI (0.994, 0.998), P<0.001], magnesium [OR=0.389, 95%CI (0.156, 0.965), P=0.042], BSA [OR=3.916, 95%CI (1.121, 13.680), P=0.032] were correlated with the incidence of peritoneal high transport characteristics. Conclusion Low serum albumin, high BSA, low magnesium and low serum uric acid were independent risk factors for high transport characteristics in initial PD patients.
The material properties and volume proportion of the fibers as well as the cross-sectional area proportion of nucleus pulposus vary greatly in different studies. The effect of these factors on the mechanical behavior of intervertebral discs (IVDs) are uncertain. The IVDs finite element models with different parameters were created to investigate the pressure, height, rotation, stress, and strain of the IVDs under loads: pure compression, rotation after compression or axial moment after compression. The results showed that the material properties of fibers had great impact on the mechanical behavior of IVDs, especially on the rotation angle. When the fiber volume ratio was small, its changes had a significant impact on the rotation angle of the IVDs. The area proportions of nucleus pulposus had relatively little effect on the mechanical behavior of IVDs. The IVDs rotation should be observed when validating the model. By adjusting the elastic modulus or volume ratio of fibers within a reasonable range, a model that could simulate the mechanical behavior of normal IVDs could be obtained. It was reasonable to make the area proportion of nucleus pulposus within 25%–50% for the IVDs finite element model. This study provides guidance and reference for finite element modeling of the IVDs and the investigation of the IVDs degeneration mechanism.