Cardiovascular disease is the leading cause of death worldwide, accounting for 48.0% of all deaths in Europe and 34.3% in the United States. Studies have shown that arterial stiffness takes precedence over vascular structural changes and is therefore considered to be an independent predictor of many cardiovascular diseases. At the same time, the characteristics of Korotkoff signal is related to vascular compliance. The purpose of this study is to explore the feasibility of detecting vascular stiffness based on the characteristics of Korotkoff signal. First, the Korotkoff signals of normal and stiff vessels were collected and preprocessed. Then the scattering features of Korotkoff signal were extracted by wavelet scattering network. Next, the long short-term memory (LSTM) network was established as a classification model to classify the normal and stiff vessels according to the scattering features. Finally, the performance of the classification model was evaluated by some parameters, such as accuracy, sensitivity, and specificity. In this study, 97 cases of Korotkoff signal were collected, including 47 cases from normal vessels and 50 cases from stiff vessels, which were divided into training set and test set according to the ratio of 8 : 2. The accuracy, sensitivity and specificity of the final classification model was 86.4%, 92.3% and 77.8%, respectively. At present, non-invasive screening method for vascular stiffness is very limited. The results of this study show that the characteristics of Korotkoff signal are affected by vascular compliance, and it is feasible to use the characteristics of Korotkoff signal to detect vascular stiffness. This study might be providing a new idea for non-invasive detection of vascular stiffness.
The stiffness of an ideal fracture internal fixation implant should have a time-varying performance, so that the fracture can generate reasonable mechanical stimulation at different healing stages, and biodegradable materials meet this performance. A topology optimization design method for composite structures of fracture internal fixation implants with time-varying stiffness is proposed, considering the time-dependent degradation process of materials. Using relative density and degradation residual rate to describe the distribution and degradation state of two materials with different degradation rates and elastic modulus, a coupled mathematical model of degradation simulation mechanical analysis was established. Biomaterial composite structures were designed based on variable density method to exhibit time-varying stiffness characteristics. Taking the bone plate used for the treatment of tibial fractures as an example, a composite structure bone plate with time-varying stiffness characteristics was designed using the proposed method. The optimization results showed that material 1 with high stiffness formed a columnar support structure, while material 2 with low stiffness was distributed at the degradation boundary and inside. Using a bone remodeling simulation model, the optimized bone plates were evaluated. After 11 months of remodeling, the average elastic modulus of callus using degradable time-varying stiffness plates, titanium alloy plates, and stainless steel plates were 8 634 MPa, 8 521 MPa, and 8 412 MPa, respectively, indicating that the use of degradable time-varying stiffness plates would result in better remodeling effects on the callus.
ObjectiveTo investigate the relationship between the level of stromal cell-derived factor-1 (SDF-1), internal carotid artery stiffness index, and non-arteritic anterior ischemic optic neuropathy (NAION) with macular edema (ME). MethodsA retrospective study. A total of 202 patients with NAION diagnosed by ophthalmic examination in Department of Ophthalmology, The Second Affiliated Hospital of Jiamusi University from January 2023 to January 2025 were included in the study. Based on the presence or absence of ME, the patients were divided into the NAION+ME group and the NAION group, with 94 and 108 cases respectively. A prediction model was constructed based on the influencing factors. To comprehensively evaluate the predictive value of SDF-1 level and carotid artery stiffness index for NAION with ME, a multidimensional analytical approach was employed. The diagnostic performance of individual and combined markers was assessed by constructing receiver operating characteristic (ROC) curves and calculating the area under the curve (AUC). Multivariate logistic regression analysis was performed to determine their independent predictive value. Stratified subgroup analyses were conducted to explore predictive differences across various populations. Cox proportional hazards regression models were established to evaluate long-term predictive value. Restricted cubic spline (RCS) analysis was applied to reveal potential nonlinear dose-response relationships. Mediation effect models were constructed to analyze the mediating role of carotid artery stiffness index in the association between SDF-1 level and NAION with ME. ResultsIn the NAION+ME group, systolic blood pressure (t=6.066), body mass index (t=2.804), disease duration (t=2.552), intraocular pressure (t=2.574), high-density lipoprotein (t=2.729), fasting blood glucose (t=2.022), glycosylated hemoglobin (t=7.235), SDF-1 level (t=14.319), and internal carotid artery stiffness index (t=2.633) were higher than those in the NAION group, while diastolic blood pressure was lower (P＜0.05). ROC curve analysis showed that the AUC of SDF-1 level combined with internal carotid artery stiffness index in predicting the risk of adverse prognosis was 0.894 [95% confidence interval (CI) 0.803-0.945], with a sensitivity of 87.98% and a specificity of 95.69%. Logistic regression analysis demonstrated significant independent correlations between SDF-1 level (OR=1.682, 95%CI 1.156-1.986), internal carotid artery stiffness index (OR=1.826, 95%CI 1.369-2.648), and the risk of ME in NAION patients (P＜0.05). Subgroup analysis revealed that elevated SDF-1 level and internal carotid artery stiffness index were associated with a higher risk of NAION with ME (Pfor trend＜0.05). RCS analysis demonstrated a nonlinear dose-response relationship between the continuous changes in SDF-1 level and internal carotid artery stiffness index and the risk of NAION with ME (P＜0.05). Mediation effect model analysis showed that internal carotid artery stiffness index played a mediating role between SDF-1 level and the risk of NAION with ME. ConclusionsSDF-1 level and internal carotid artery stiffness index are independent risk factors for ME in NAION patients. The combined detection of these two indicators holds significant value in predicting disease progression.
The prevalence of cardiovascular disease in our country is increasing, and it has been a big problem affecting the social and economic development. It has been demonstrated that early intervention of cardiovascular risk factors can effectively reduce cardiovascular disease-caused mortality. Therefore, extensive implementation of cardiovascular testing and risk factor screening in the general population is the key to the prevention and treatment of cardiovascular disease. However, the categories of devices available for quick cardiovascular testing are limited, and in particular, many existing devices suffer from various technical problems, such as complex operation, unclear working principle, or large inter-individual variability in measurement accuracy, which lead to an overall low popularity and reliability of cardiovascular testing. In this study, we introduce the non-invasive measurement mechanisms and relevant technical progresses for several typical cardiovascular indices (e.g., peripheral/central arterial blood pressure, and arterial stiffness), with emphasis on describing the applications of biomechanical modeling and simulation in mechanism verification, analysis of influential factors, and technical improvement/innovation.
Lower extremity movement is a complex and large range of limb movement. Arterial stents implanted in lower extremity are prone to complex mechanical deformation, so the stent is required to have high comprehensive mechanical properties. In order to evaluate the mechanical property of different stents, in this paper, finite element method was used to simulate and compare the mechanical properties of six nitinol stents (Absolute Pro, Complete SE, Lifestent, Protégé EverFlex, Pulsar-35 and New) under different deformation modes, such as radial compression, axial compression/tension, bending and torsion, and the radial support performance of the stents was verified by experiments. The results showed that the comprehensive performance of New stent was better than other stents. Among which the radial support performance was higher than Absolute Pro and Pulsar-35 stent, the axial support performance was better than Complete SE, Lifestent and Protégé EverFlex stent, the flexibility was superior to Protégé Everflex stent, and the torsion performance was better than Complete SE, Lifestent and Protégé Everflex stent. The TTR2 type radial support force tester was used to test the radial support performance of 6 types, and the finite element analysis results were verified. The mechanical properties of the stent are closely related to the structural size. The result provides a reference for choosing a suitable stent according to the needs of the diseased location in clinical applications.
Objective To investigate the difference of effectiveness between medial-lateral approach and posteromedian approach in the release of elbow stiffness after distal humeral fracture surgery. Methods A retrospective analysis was conducted on the clinical data of 41 patients with elbow stiffness following medial and lateral plate fixation for distal humeral fractures, admitted between January 2021 and June 2023 and meeting selection criteria. Patients were divided into the medial-lateral approach release group (study group, 20 cases) and the posteromedian approach release group (control group, 21 cases) based on surgical approach. Baseline data including age, gender, affected side, body mass index, disease duration, and preoperative extension angle, flexion angle, range of motion, visual analogue scale (VAS) pain score, Mayo elbow performance score, ulnar nerve symptoms, and heterotopic ossification showed no significant difference between groups (P>0.05). The operation time, intraoperative blood loss, and complication incidence were recorded and compared between groups. Clinical effectiveness was evaluated using pre- and postoperative Mayo score, VAS score, elbow extension/flexion angles, and range of motion on the affected side. Statistical analysis focused on changes in these indicators relative to preoperative values. Results There was no significant difference in operation time and intraoperative blood loss between the two groups (P>0.05). Patients in both groups were followed up 15-36 months, with a mean of 23.8 months; there was no significant difference in the follow-up time between the two groups (t=?1.542, P=0.131). In the control group, 1 patient had obvious subcutaneous hematoma and 5 patients had poor wound healing within 2 months after operation, all of which were cured by symptomatic treatment, while no related complications occurred in the study group, there was a significant difference in poor wound healing incidence between the two groups (P<0.05). At last follow-up, 2 patients in the study group and 3 patients in the control group had mild symptoms of ulnar nerve numbness, and there was no significant difference in the incidence of ulnar nerve symptoms (P>0.05). All patients had no recurrence or new onset of heterotopic ossification, no skin necrosis or reoperation due to complications. At last follow-up, elbow extension angle, flexion angle, flexion-extension range of motion, VAS score, and Mayo score significantly improved in both groups when compared with the preoperative ones (P<0.05). There was no significant difference between the change values in elbow extension angle and VAS score between the two groups (P>0.05); the change values in flexion angle, range of motion, and Mayo score in the study group were significantly better than those in the control group (P<0.05). Conclusion The medial-lateral approach can release the elbow stiffness and concurrently remove the medial, lateral, or posterior lateral plates. The incision minimizes disruption to rehabilitation exercises and reduces complications like inadequate wound healing, ultimately leading to improved treatment outcomes.
Objective To evaluate the results of open arthrolysis by elevated the lateral and medial collateral l igament-musculature complex from the supracondylar ridge of the humerus in treatment of post-traumatic elbow stiffness. Methods From March 2003 to December 2007, 33 patients with post-traumatic elbow stiffness were treated with open arthrolysis by elevated the lateral and medial collateral l igament-musculature complex from the supracondylar ridge of the humerus. There were 23 males and 10 females, aged 17-70 years old (mean 41.8 years old). According to Morrey, 15 caseswere extremely serious (less than 30° extension-flexion arc) and 18 cases were serious (30-60° extension-flexion arc). The range of motion of the elbow stiffness was (32.5 ± 28.9)° and the Mayo score was 51.9±13.1 before operation. All initial fractures were healed according to cl inical examination and X-rays films. All patients present with a post-traumatic elbow stiffness and the average period from initial trauma to elbow arthrolysis was 16.9 months (2-72 months). Results Wound infection occurred in 1 patient and cured after dressing change and anti-infectious treatment. The wounds healed by first intension in 32 cases. No patient showed sign of elbow instabil ity and debil itating pain. All patients were followed up 6 months to 5 years (mean 3.3 years). At last follow up, the Mayo score was 82.3 ± 14.4 and the range of motion of elbow stiffness was (108.8 ± 36.0)°; showing significant differences when compared with preoperation (P lt; 0.05). According to Mayo evaluation, the results were excellent in 11 cases, good in 18 cases, fair in 2 cases, and poor in 2 cases, the excellent and good rate was 87.88%. Thirty-one patients achieve satisfactory results. Two patients were not satisfied with the result, but the satisfactory results were achieved by a second arthrol ysis. Conclusion Open elbow arthrolysis and postoperative rehabil itation for patients with elbow stiffness can improve joint function and ensure the stabil ity of elbows.
ObjectiveTo compare the biomechanical characteristics of self-made nickel-titanium shape memory alloy stepped plate with calcaneal plate and cannulated compression screws in fixing calcaneal osteotomy.MethodsCalcaneal osteotomy was operated on 6 fresh-frozen lower limbs collected from donors. Then three kinds of fixation materials were applied in random, including the self-made nickel-titanium shape memory alloy stepped plate (group A), calcaneal plate (group B), and cannulated compression screws (group C). Immediately after fixation, axial loading of 20-600 N and 20 N/s in speed was introduced to record the biomechanical data including maximum displacement, elastic displacement, and maximum load. Then fatigue test was performed (5 Hz in frequency and repeat 3 000 times) and the same axial loading was introduced to collect the biomechanical data. Finally, the axial compression stiffness before and after fatigue test were calculated.ResultsThere was no significant difference in the axial compression stiffness between pre- and post-fatigue test in each group (P>0.05). However, the axial compression stiffness was significant higher in group A than that in groups B and C both before and after fatigue test (P<0.05). No significant difference was found between group B and group C (P>0.05).ConclusionSelf-made nickel-titanium shape memory alloy stepped plate is better than calcaneal plate and cannulated compression screws in axial load stiffness after being used to fix calcaneal osteotomy.
Objective To explore the effectiveness of arthroscopic release of elbow joint assisted by medial small incision ulnar nerve release in the treatment of non-traumatic elbow stiffness. MethodsThe clinical data of 15 patients with non-traumatic elbow stiffness treated with arthroscopic release of elbow joint assisted by medial small incision ulnar nerve release between April 2019 and September 2023 were retrospectively analyzed. There were 6 males and 9 females with an average age of 46 years ranging from 34 to 56 years. The causes included rheumatoid arthritis in 3 cases, gouty arthritis in 2 cases, loose bodies in 3 cases, and elbow osteoarthritis in 7 cases. There were 4 cases with ulnar neuritis and 3 cases with synovial osteochondromatosis. The duration of elbow stiffness ranged from 6 to 18 months, with an average of 10 months. The operation time and intraoperative blood loss were recorded. The effectiveness was evaluated by visual analogue scale (VAS) score, range of elbow motion (maximum flexion, maximum extension, and total flexion and extension), Mayo score, and Hospital for Special Surgery (HSS) elbow score. ResultsThe operation time was 60-90 minutes, with an average of 65 minutes, and the intraoperative blood loss was 40-100 mL, with an average of 62 mL. All patients were followed up 13-18 months, with an average of 14 months. There was no complication such as vascular and nerve injury, poor wound healing, collateral ligament injury, elbow joint space narrowing, osteophyte proliferation, or loose body formation around the joint. At last follow-up, the elbow range of motion (maximum flexion, maximum extension, and total flexion and extension), VAS score, and Mayo score significantly improved when compared with those before operation (P<0.05). The HSS elbow score was 85-95, with an average of 92; 12 cases were excellent, 3 cases were good, and the excellent and good rate was 100%. ConclusionArthroscopic release of elbow joint assisted by medial small incision ulnar nerve release is an effective way to treat non-traumatic elbow stiffness, which has the advantages of small trauma, short operation time, and good effectiveness. It can carry out early elbow rehabilitation training and significantly improve elbow function.
OBJECTIVE: Extension stiffness of knee joint is always treated by the quadricepsplasty, but the main deficiency of this method is that patient feels weakness of lower limb and easily kneels down. The aim of this article is to explore the method to resolve the complications after quadricepsplasty. METHODS: Since 1978 to 1997, on the basis of traditional procedures of quadricepsplasty, sartorius muscle was used to reinforce the extension of knee joint. The lower 2/3 of sartorius muscle was fully dissociated only with its insertion intact. A tendon-periosteal-bone flap, about 2 cm in width, was managed on the anterior surface of patella, with its pedicle on the medial edge of patella. The tendon-periosteal-bone flap was used to fix the dissociated sartorious into patella to reinforce the extension of knee joint. The very lower part of sartorius was mainly aponeurosis, with the help of an aponeurosis bundle of iliotibial tract, it was fixed into the insertion of patellar ligament, through a bony tunnel chiseled adjacent to the insertion of patellar ligament. By now the movement of knee joint extension was strengthened by the transferred sartorius muscle. Postoperatively, every patient was required to extend and flex knee joint actively and/or passively. Altogether 12 patients were treated, 9 of them were followed up with an average of 14 months. RESULTS: The average movement was increased from 15 degrees to 102 degrees, and the average myodynamia was improved from grade II to grade IV. CONCLUSION: Traditional quadricepsplasty co-operated with transfer of sartorius muscle can strengthen the myodynamia of knee joint extension. It is simple method and can really achieve good function.