【Abstract】 Objective The present study employed both static and dynamic imaging modal ities to study bothintra- and extravascular events attributing to steroid-associated osteonecrosis (ON) using an experimental protocol with a single low-dose l i ppolysaccharide (LPS) injection and subsequently three injections of high-dose methylprednisolone (MPS). Methods Fourteen 28-week-old male New Zealand white rabbits received one intravenous injection of LPS (10 μg/ kg). After 24 hours, three injections of 20 mg/kg of MPS were given intramuscularly at a time interval of 24 hours. Additional 6 rabbits were used as controls. Dynamic MRI was performed on bilateral femora for local intraosseous perfusion before and after LPS injection. Blood samples were collected for haematological examinations before and after LPS injection. Bilateral femora were dissected and decalcified for microCT-based microangiography. ON lesion, intravascular thrombus and extravascular marrow fat cell size were examined histopathologically. Results Intravascular thrombus was observed in all ON rabbits. Extravascular marrow fat cell size was significantly increased in ON rabbits than that of the controls (P lt; 0.05). Compared to basel ine, a significant decrease in ratio of tissue-type-plasminogen-activator/plasminogen-activator inhibitor 1,activated-partial- thromboplatin-time, and a significant increase in ratio of low-density-l ipoprotein/high-density-l ipoprotein were only found in ON rabbits (P lt; 0.05). Dynamic MRI showed a significant decrease in the perfusion index ‘maximum enhancement’ in the ON rabbits (P lt; 0.05) and microCT-based microangiography showed blocked stem vessels in ON samples.Overall, 93% of the rabbits (13/14) developed ON and no rabbits died throughout the experiment period. Conclusion Bothintra- and extravascular events were found attributing to the steroid- associated ON based on our experimental protocol with a single low-dose LPS injection and subsequent three injections of high-dose MPS. Both high ON incidence and no mortal ity in rabbits treated with this inductive protocol suggested its effectiveness for future studies on evaluation of therapeutic efficacy of interventions developed for prevention of steroid-associated ON.
The surgical installation accuracy of the components in unicompartmental knee arthroplasty (UKA) is an important factor affecting the joint function and the implant life. Taking the ratio of the medial-lateral position of the femoral component relative to the tibial insert (a/A) as a parameter, and considering nine installation conditions of the femoral component, this study established the musculoskeletal multibody dynamics models of UKA to simulate the patients’ walking gait, and investigated the influences of the medial-lateral installation positions of the femoral component in UKA on the contact force, joint motion and ligament force of the knee joint. The results showed that, with the increase of a/A ratio, the medial contact force of the UKA implant was decreased and the lateral contact force of the cartilage was increased; the varus rotation, external rotation and posterior translation of the knee joint were increased; and the anterior cruciate ligament force, posterior cruciate ligament force and medial collateral ligament force were decreased. The medial-lateral installation positions of the femoral component in UKA had little effect on knee flexion-extension movement and lateral collateral ligament force. When the a/A ratio was less than or equalled to 0.375, the femoral component collided with the tibia. In order to prevent the overload on the medial implant and lateral cartilage, the excessive ligament force, and the collision between the femoral component and the tibia, it is suggested that the a/A ratio should be controlled within the range of 0.427?0.688 when the femoral component is installed in UKA. This study provides a reference for the accurate installation of the femoral component in UKA.
ObjectiveTo conclude the effectiveness of arthroscopy combined with Burks and SchaVer's approach in the treatment of posterior cruciate ligament (PCL) avulsion fractures in a floppy lateral position.
MethodsBetween May 2010 and March 2014, 21 patients with PCL avulsion fractures were treated. There were 13 males and 8 females, aged 21 to 62 years (mean, 39.1 years). The causes included traffic accident injury in 10 cases, sports injury in 5 cases, and falling injury from height in 6 cases. The time from injury to hospital was 1-6 days (mean, 2.5 days). The results of posterior drawer test were all positive, and the results of anterior drawer test and lateral stress test were all negative. The Lysholm score was 28.0±5.5 before operation. And the American Orthopaedic Foot and Ankle Society (IKDC) score was 46.2±7.6 before operation. According to Meyer standards for fractures classification, 11 cases were rated as type II and 10 cases as type III. Arthroscopy was used to inspect and treat the intra-articular lesions, then avulsion fracture was fixed by Burks and SchaVer's approach in lateral position. Postoperative functional exercises were performed.
ResultsPrimary healing of incision was obtained, without nerve and vascular injury or joint infection. All patients were followed up 18-36 months (mean, 27.2 months). The X-ray films of the knee joint showed good fractures reduction and healing at 3 months after operation. The results of posterior drawer test and reverse Lachman test were negative. The knee range of motion was recovered to normal level. At last follow-up, the Lysholm score of the knee joint was significantly improved to 90.9±1.4 from preoperative one (t=54.584, P=0.000), and the IKDC score was significantly increased to 90.5±5.3 from preoperative one (t=15.638, P=0.000), including 19 cases of grade A and 2 cases of grade B.
ConclusionA combination of arthroscopy and Burks and SchaVer's approach for the treatment of PCL avulsion fractures in a floppy lateral position has the advantages of minimal invasion and safe approach, short operative time, and early postoperative rehabilitation exercises, so it can provide satisfactory function recovery of the knee joint.
Abstract： Objective To investigate the early and mid-term outcomes of morphologic tricuspid valve replacement by means of intravalvular implantation in corrected transposition of great arteries（cTGA）. Methods From January 2009 to January 2012，11 patients with cTGA were surgically treated in Fu Wai Hospital. There were 9 male patients and 2 female patients with their mean of age of（37.8±11.7）years and mean body weight of（73.0±11.3）kg. All the patients underwent morphologic tricuspid valve replacement with preservation of the entire valvular and subvalvular apparatus. Simultaneous surgical procedures included repair of ventricular septal defect in 2 patients，repair of atrial septal defect in 4 patients，pulmonary valvuloplasty in 1 patient，reconstruction of functional right ventricular outflow tract in 4 patients and repair of coronary-pulmonary artery fistula in 1 patient. Postoperative New York Heart Association （NYHA） classification, cardiothoracic ratio, morphological right ventricle ejection fraction, end-diastolic dimension of morphological right ventricle and left atrium were evaluated during follow-up. Results All the 11 patients were successfully surgically treated and followed up for an average duration of（13.0±10.6）months. There was no statistical difference between postoperative and preoperative average cardiothoracic ratio （0.54±0.06 vs. 0.57±0.09，t=1.581，P＞0.05），morphologic right ventricle ejection fraction （52.8%±9.0% vs. 54.9%±9.5%, t =0.712，P＞0.05），and end-diastolic dimension of . morphological right ventricle （54.3±7.5 mm vs. 56.9±9.2 mm，t =0.988，P＞0.05）. There was statistical difference between postoperative and preoperative average end-diastolic dimension of left atrium（42.1±8.9 mm vs. 53.4±11.1 mm，t =3.286，P＜0.05）and NYHA classification（Z = -2.640，P＜0.05）. Conclusion Intravalvular implantation of morphologic tricuspid prosthesis can protect the physiological structure of morphologic right ventricular and prevent furtherdamage to its function caused by morphologic tricuspid valve insufficiency. Postoperative dimension of morphologic left atrium and cardiac function are significantly improved. The early and mid-term outcomes are satisfactory．
To solve the problem of stent malapposition of intravascular stents, explore the design method of intravascular body-fitted stent structure and to establish an objective apposition evaluation method, the support and apposition performance of body-fitted stent in the stenotic vessels with different degrees of calcified plaque were simulated and analyzed. The traditional tube-mesh-like stent model was constructed by using computational aided design tool SolidWorks, and based on this model, the body-fitted stent model was designed by means of projection algorithm. Abaqus was used to simulate the crimping-expansion-recoil process of the two stents in the stenotic vessel with incompletely calcified plaque and completely calcified plaque respectively. A comprehensive method for apposition evaluation was proposed considering three aspects such as separation distance, fraction of non-contact area and residual volume. Compared with the traditional stent, the separation distances of the body-fitted stent in the incompletely calcified plaque model and the completely calcified plaque model were decreased by 21.5% and 22.0% respectively, the fractions of non-contact areas were decreased by 11.3% and 11.1% respectively, and the residual volumes were decreased by 93.1% and 92.5% respectively. The body-fitted stent improved the apposition performance and was effective in both incompletely and completely calcified plaque models. The established apposition performance evaluation method of stent considered more geometric factors, and the results were more comprehensive and objective.
ObjectiveTo evaluate clinical results of left ventricular retraining followed by double switch operation (DSO) for patients with congenitally corrected transposition of the great arteries (CCTGA) and a deconditioned morphologically left ventricle (mLV).
MethodsClinical data of 14 patients with CCTGA and a deconditioned mLV who underwent surgical therapy in Fu Wai Hospital from May 2005 to May 2011 were retrospectively analyzed. There were 8 male and 6 female patients with their age of 2.5-72.0 (34.4±24.0) months and body weight of 5.1-23.0 (12.7±4.9) kg. Preoperative diagnosis was confirmed by echocardiography, angiography or cardiac catheterization. Major concomitant anomalies included tricuspid regurgitation (TR) in 13 patients, restrictive ventricular septal defect in 10 patients, atrial septal defect or patent foramen ovale in 7 patients, mild pulmonary valve stenosis in 4 patients, patent ductus arteriosus in 4 patients, and third-degree atrioventricular block in 1 patient. All the patients underwent first-stage morphologic left ventricular retraining under general anesthesia followed by second-stage atrial switch and arterial switch operations (DSO) under cardiopulmonary bypass with the interval of 0.67-34.0(10.23±9.47)months.
ResultsAfter the first-stage morphologic left ventricular retraining, there was no postoperative complication or death. During follow-up, mLV end-diastolic diameter (mLVEDd) and posterior wall thickness of mLV were significantly larger than preoperative parameters (P < 0.05). The interventricular septum moved partially towards morphologically right ventricle (mRV). TR degree was significantly decreased, the pressure gradient across the pulmonary artery band was significantly increased (P < 0.05), and left ventricular ejection fraction (LVEF) was not statistically different from preoperative LVEF. And mLV/mRV pressure ratio was significantly increased (P < 0.05). After the second-stage DSO, 2 patients died with the in-hospital mortality of 14.3% (2/14). The causes of death included serious arrhythmia, circulatory collapse and sudden death. Early postoperative complications included pulmonary infection in 6 patients, atrial arrhythmias in 2 patients, pleural effusion in 2 patients, pneumothorax in 1 patient, diaphragmatic paralysis cured by diaphragm placation in 1 patient, respiratory tract hemorrhage in 1 patient, mild aortic insufficiency in 1 patient, peritoneal dialysis for 1 patient, extracorporeal membrane oxygenation for 1 patient, and tracheal intubation for a second time for 1 patient. All the 12 patients who were discharged alive were followed up for 2 to 8 years. One patient died during follow-up with the late mortality of 8.33% (1/12), and the cause of death was serious arrhythmia and circulatory collapse. Eight patients were in New York Heart Association (NYHA) classⅠ, and 3 patients were in NYHA class Ⅱ. Major late complications included left ventricular dysfunction in 3 patients, moderate aortic valve regurgitation in 3 patients, and moderate mitral valve regurgitation in 1 patient.
ConclusionShort-term clinical results of left ventricular retraining followed by DSO for patients with CCTGA and a deconditioned mLV are satisfactory, and its middleand long-term results need further follow-up. But postoperative left ventricular dysfunction and new-onset aortic valve regurgitation deserve more attention.
Objective?To observe the effectiveness of posterior approaches for the treatment of posterior coronal fractures of tibial plateau, and to analyze the fracture morphology, radiographic features, and the recognition of Schatzker classification.?Methods?Between June 2003 and June 2009, 23 patients with posterior coronal fractures of tibial plateau were treated surgically by posterior approaches. There were 15 males and 8 females with an average age of 38 years (range, 32-56 years). All patients had closed fractures. Fracture was caused by traffic accident in 15 cases, by sports in 3 cases, and by falling from height in 5 cases. According to Moore classification, there were 10 cases of type I, 9 cases of type II, and 4 cases of type IV. The X-ray films, CT scanning, and three-dimensional reconstruction were performed. The time from injury to operation was 3-14 days (mean, 6 days).?Results?After operation, 17 cases had anatomical reduction and 6 had normal reduction. Incisions healed by first intention. All cases were followed up 12 to 36 months (mean, 24 months). The average fracture healing time was 7.6 months (range, 6-9 months). No related complication occurred, such as nerve and vessel injuries, failure in internal fixation, ankylosis, traumatic osteoarthritis, and malunion. According to Rasmussen’s criteria for the function of the knee, the results were excellent in 14 cases, good in 7 cases, and fair in 2 cases with an excellent and good rate of 91.3%.?Conclusion Posterior coronal fracture of tibial plateau is rare, which has distinctive morphological features, and Schatzker classification can not contain it totally. The advantages of posterior approach include reduction of articular surface under visualization, firm fixation, less complications, and earlier functional exercise, so it is an ideal surgical treatment plan.
Real-time acquisition of pulmonary ventilation and perfusion information through thoracic electrical impedance tomography (EIT) holds significant clinical value. This study proposes a novel method based on the rime (RIME) algorithm-optimized variational mode decomposition (VMD) to separate lung ventilation and perfusion signals directly from raw voltage data prior to EIT image reconstruction, enabling independent imaging of both parameters. To validate this approach, EIT data were collected from 16 healthy volunteers under normal breathing and inspiratory breath-holding conditions. The RIME algorithm was employed to optimize VMD parameters by minimizing envelope entropy as the fitness function. The optimized VMD was then applied to separate raw data across all measurement channels in EIT, with spectral analysis identifying relevant components to reconstruct ventilation and perfusion signals. Results demonstrated that the structural similarity index (SSIM) between perfusion images derived from normal breathing and breath-holding states averaged approximately 84% across all 16 subjects, significantly outperforming traditional frequency-domain filtering methods in perfusion imaging accuracy. This method offers a promising technical advancement for real-time monitoring of pulmonary ventilation and perfusion, holding significant value for advancing the clinical application of EIT in the diagnosis and treatment of respiratory diseases.
In order to eliminate the influence of motion artifacts, high-frequency noise and baseline drift on photoplethysmographic (PPG), and to obtain the accurate value of heart rate in motion state, this paper proposed a de-noising method of PPG signal based on normalized least mean square (NLMS) adaptive filtering combining ensemble empirical mode decomposition(EEMD). Firstly, the PPG signal containing noise is passed through an adaptive filter with a 3-axis acceleration sensor as a reference signal to filter out motion artifacts. Secondly, the PPG signal is decomposed by EEMD to obtain a series of intrinsic modal function (IMF) according to the frequency from high to low. The threshold range of the signal is judged by the permutation entropy (PE) criterion, thereby filtering out the high frequency noise and the baseline drift. The experimental results show that the Pearson correlation coefficient between the calculated heart rate of PPG signal and the standard heart rate based on electrocardiogram (ECG) signal is 0.731 and the average absolute error percentage is 6.10% under different motion states, which indicates that the method can accurately calculate the heart rate in moving state and is beneficial to the physiological monitoring under the state of human motion.
Objective To observe the clinical characteristics of steroid-induced ocular hypertension (SIOH) in patients with uveitis, and explore the relationship between its clinical phenotype and gene polymorphism. Methods A retrospective case-control study. From July 2019 to December 2020, 576 patients with uveitis who were treated with glucocorticoid eye drops in Tianjin Medical University Eye Hospital were included in the study. Among them, there were 175 confirmed glucocorticoid responders (SRs) and 401 glucocorticoid non-responders (NRs). Seventy cases of SRs (age ≥18 years) using 1% prednisone acetate eye drops were selected as the experiment group and 64 cases of NRs were selected as the control group. The polymorphism of rs2523864 and rs3873352 of human leukocyte antigen complex group (HCG) 22 gene were detected by Sanger sequencing. To observe the clinical characteristics of SIOH after the use of glucocorticoid eye drops, and the correlation between rs2523864 and rs3873352 and the occurrence of SIOH. Differences among groups were compared with the Chi-square test or Fisher's exact test. The correlation between the occurrence of SIOH and the range of intraocular pressure increases after glucocorticoid use and the rs2523864 and rs3873352 loci were compared using the odds ratio (OR) and its 95% confidence interval (CI). Results SIOH occurred in 175 (30.4%, 175/576) of 576 patients. Among them, there were 96 males (54.9%, 96/175) and 79 females (45.1%, 79/175); the average age was 33.64±17.40 years. Steroid high responders (HRs) and steroid moderate responders (MRs) were 58 (33.1%, 58/175) and 117 (66.9%, 117/175) cases. The medication time for the increase in intraocular pressure in MRs that was 33 (19, 56) days, and in HRs that was 28 (14, 36) days, the difference of which was significant (Z=－1.999, P=0.046). No differences were found in daily doses of ocular hypertension induced by 1% prednisone acetate eye drops between MRs which was 4.24 (3.46, 4.66) drops/day and HRs that was 4.32 (3.84, 5.36) drops/day (Z=－1.676, P=0.094). The genotype and allele frequency distribution of the rs3873352 locus in the case group and HRs group were significantly different from those in the control group (P＜0.05). The intraocular pressure with rs3873352 GG genotype after the medication was higher than that with GC and CC genotype (Z=2.855, 2.628; P=0.013, 0.026), whereas there was no significant difference between different genotypes of rs2523864 (Z=3.580, P＞0.05). Genetic model analysis revealed the risk of SIOH in rs3873352 G allele carriers (GG+GC) was 2.048 times that of non-G allele carriers (OR=2.048, 95%CI: 1.027-4.081, P=0.041). The genotype and allele frequency of rs2523864 locus showed no significant difference between different group (P＞0.05). Conclusions After the use of glucocorticoid eye drops, HRs have an earlier increase in intraocular pressure than MRs. HCG22-rs3873352 gene polymorphism is related to the occurrence of SIOH, GG genotype increases the risk of SIOH, and G allele is a risk gene for SIOH.
