RATIONALE/OBJECTIVE

Simulation-based training allows surgeons to practice technical skills in low-stakes environments. This study aimed to evaluate the appropriateness of a locally developed cephalous tissue analogue model for Z-plasty technique training, addressing the lack of standardized simulation training tools in the Philippines.

Fifteen board-certified plastic surgeons participated, performing the Z-plasty on the cephalous tissue analogue simulator, which was developed using a gelatin, sorbitol, and glycerin mixture reinforced by a mesh base. The participants watched a standardized Zplasty technique video and practiced on the simulator before providing feedback. Face validity was assessed through a Likert-scale questionnaire, with a passing score of 40/50.

Of the participants, 93.3% agreed that the model replicated the visual appearance and anatomical orientation necessary for Z-plasty, while 86.6% affirmed its utility in preprocedural planning. However, only 46.7% found the simulator's tissue elasticity adequate, and 20% agreed that it effectively mimicked the interaction between surgical instruments and tissue. The model was unable to consistently retain sutures, particularly for flap corners.

The cephalous tissue analogue model successfully simulated incision and visual orientation but requires refinements in tissue elasticity and suture retention to fully meet training needs for Z-plasty. Future efforts will focus on prototype improvements and content validation to better support simulation-based surgical training.

OBJECTIVE: To evaluate the effects of posterior cruciate ligament(PCL) resection on soft tissue elasticity and knee stability in total knee arthroplasty(TKA). METHODS: Six adult cadaveric knee specimens (involving 10 knees) were included in the study. With the assistance of the robotic system(TiRobot Recon, TINAVI, Beijing), total knee arthroplasty (TKA) was performed sequentially using cruciate retaining (CR) prostheses and posterior stabilizing (PS) prostheses. Between the two surgical procedures, the femoral and tibial osteotomy surfaces were not altered;only the posterior cruciate ligament (PCL) was resected and the intercondylar fossa was treated. After installing the femoral trial component, a soft tissue balance solver was used to apply tension ranging from 30 N to 90 N in 5 N increments at 0°, 10°, and 90° of knee flexion. Meanwhile, the medial and lateral joint gaps were measured synchronously. Based on the tension-gap coupling data, the equivalent elastic coefficients of the medial and lateral soft tissue sleeves at different knee flexion angles, as well as the range of the joint line convergence angle (JLCA) under fixed varus-valgus stress, were calculated. Additionally, the gap balance status under 80 N of tension was analyzed. Self-control comparisons of each indicator were conducted before and after PCL resection to analyze the change patterns. RESULTS: After PCL resection, in the fully extended position (knee flexion 0°). The medial equivalent elastic coefficient was 32.2 (25.7, 63.3) N·mm^-1 for the CR prosthesis and 27.7 (22.0, 51.9) N·mm^-1 for the PS prosthesis, and the statistically significant difference (P=0.013). The range of JLCA was 0.41°(0.26, 0.55)° for the CR prosthesis, which was smaller than 0.75° (0.40, 0.98)° for the PS prosthesis, and the difference was statistically significant(P=0.041). At 90° of knee flexion, the medial joint gap was 10.7(10.1, 11.7) mm for the CR prosthesis, which was smaller than 12.1(10.9, 15.1) mm for the PS prosthesis, with a statistically significant difference(P=0.011). No statistically significant differences were observed in other joint gaps. CONCLUSION PCL resection reduces the rigidity of the medial soft tissues in the fully extended knee and increases the medial joint gap in the flexed position, thereby affecting knee stability and balance. This finding suggests that PS and CR prostheses may require different morphological designs, and there should be differences in indications and osteotomy strategies between CR-TKA and PS-TKA. CR-TKA is more suitable for patients with preoperative medial soft tissue laxity.
Humans ; Posterior Cruciate Ligament/physiopathology* ; Knee Joint/physiopathology* ; Arthroplasty, Replacement, Knee ; Elasticity ; Male ; Female ; Middle Aged ; Aged ; Biomechanical Phenomena ; Adult

OBJECTIVE: To evaluate the partial biomechanical properties of the posterior occipital muscles (rectus capitis posterior major, rectus capitis posterior minor, and obliquus capitis inferior) in patients with cervical vertigo. METHODS: A total of 30 patients with cervical vertigo admitted from April 2024 to September 2024 were included in the vertigo group, and 30 age-and gender-matched healthy subjects were recruited as the normal group. In the vertigo group, there were 21 females and 9 males, with an average age of (24.00±2.25) years;in the normal group, there were 22 females and 8 males, with an average age of (23.00±3.00) years. Shear wave elastography was used to measure the thickness and stiffness of the posterior occipital muscles in both groups. RESULTS: In the vertigo group, there were no statistically significant differences in the Young's modulus values (E) of stiffness of the posterior occipital muscles (rectus capitis posterior major, rectus capitis posterior minor, obliquus capitis inferior) between the left and right sides(P>0.05). The Young's modulus values(E) of stiffness of the right posterior occipital muscles (rectus capitis posterior major, rectus capitis posterior minor, obliquus capitis inferior) in the cervical vertigo group were (39.66±8.21) kPa, (45.61±5.85) kPa, and (43.73±5.22) kPa, respectively, which were significantly higher than those in the normal group 33.97(17.76) kPa, 41.38(8.99) kPa, 38.27(12.58) kPa, with statistically significant differences (P<0.05). In the vertigo group, the Young's modulus values(E) of stiffness of the left rectus capitis posterior major and left obliquus capitis inferior were (40.41±9.13) kPa and (42.11±6.20) kPa, respectively, which were significantly greater than those in the normal group (33.30±11.31) kPa, 38.94(14.62) kPa, with statistically significant differences(P<0.05);however, there was no statistically significant difference in the left rectus capitis posterior minor between the two groups(P>0.05). In the vertigo group, there were no statistically significant differences in the stiffness of the posterior occipital muscles (rectus capitis posterior major, rectus capitis posterior minor, obliquus capitis inferior) between the left and right sides(P>0.05). Additionally, there were no statistically significant differences in the thickness of the bilateral posterior occipital muscles between the vertigo group and the normal group (P>0.05). CONCLUSION The posterior occipital muscles of patients with cervical vertigo are stiffer than those of healthy individuals, while there is no significant difference in muscle thickness between the two groups.
Humans ; Female ; Male ; Elasticity Imaging Techniques/methods* ; Adult ; Vertigo/physiopathology* ; Neck Muscles/physiopathology* ; Young Adult

Male factor infertility has been rising, which accounts for up to 30% of infertility cases and contributes to 50% of overall cases. The aim of this review is to explore the recent advances that have emerged in the field through a narrative review. A comprehensive literature search was conducted using multiple databases, including the Cochrane Library, PubMed, Scopus, and Web of Science. Gray literature was also reviewed through ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform. The findings were presented narratively to encompass the extensive range of published data on male infertility. Significant strides have been made in the field of male infertility, particularly with biomarkers, shear wave elastography, 3-dimensional (3D) bioprinting, artificial intelligence (AI), and robotic and microsurgical treatment, offering promising avenues for diagnosis and treatment. Continued research and technological innovation are essential to further improve outcomes for patients facing male factor infertility.
Humans ; Male ; Infertility, Male/diagnosis* ; Artificial Intelligence ; Elasticity Imaging Techniques ; Bioprinting ; Microsurgery ; Biomarkers ; Robotic Surgical Procedures

Objective:To explore the factors influencing adherence to voice therapy among patients with voice disorders in China. Methods:Patients with voice disorders who visited the Voice Therapy Center at Sun Yat-sen Memorial Hospital, Sun Yat-sen University, from February to May 2022 were enrolled in the study. Adherence was assessed using the URICA-Voice scale, while influencing factors were assessed through the Voice Handicap Index（VHI） scale and a general information questionnaire. Correlation analysis was conducted using univariate and multivariate logistic regression analysis. Results:A total of 247 patients were included in the study, comprising 57 males（23.08%） and 190 females（76.92%）. The results revealed that: ①Female patients demonstrated higher likelihood of being in the contemplation stage（OR=0.22） compared to males. ②Patients with a monthly family income per capita>6 000 yuan were more likely to be in the contemplation stage than those with<3 000 yuan with an OR = 13.94. ③High vocal-demand occupations increased contemplation stage probability（OR=7.70） compared to moderate-demand occupations. ④Residence within 30-minute commute predicted action/maintenance stages（OR=7.14） versus≥60-minute commute. ⑤Patients whose occupations had high voice demands were more likely to be in the action and maintenance stages than those with average voice demands, with an OR of 16.20. Conclusion:Gender, monthly family income per capita, occupational voice demands, and distance to the hospital significantly impact the URICA-Voice compliance stages of patients. Patients who are female, have higher family income, have occupations with high voice demands, and live closer to the hospital exhibit higher compliance with voice training.
Humans ; Male ; Female ; Voice Disorders/therapy* ; Patient Compliance ; Voice Training ; Surveys and Questionnaires ; China ; Middle Aged ; Adult ; Voice Quality ; Logistic Models ; Aged

The purpose of the present study was to investigate the effects of resistance combined with aerobic chrono-exercise on the common carotid artery elasticity and hemodynamics. 24 healthy young men (21.96±0.43 years old) underwent a single acute resistance combined with aerobic exercise intervention at eight time periods (6, 8, 10, 12, 14, 16, 18, and 20 o'clock). The axial flow velocity and diameter waveforms of the common carotid artery were measured, and the hemodynamics were calculated using the classical hemodynamic theory before exercise, immediately after exercise, 10 min and 20 min after exercise. The results showed that during exercise recovery, systolic and mean pressures decreased more markedly after exercise at 8 o'clock (P < 0.05); At 20 min post-exercise, arterial stiffness index and pressure-strain elastic modulus after exercise at 6 o'clock were reduced compared with the resting state, but were significantly elevated after exercise at 20 o'clock (P < 0.05). Immediately after exercise, the pressure rise was higher after exercise at 6 o'clock and the mean wall shear stress was higher after exercise at 20 o'clock (P < 0.05). These results suggest that resistance combined with aerobic chrono-exercise produces different effects on common carotid artery hemodynamics in young men. A single acute session of resistance combined with aerobic exercise at 8 o'clock is more effective in lowering blood pressure. Exercise at 6 o'clock is beneficial to improve arterial elasticity but is not recommended for young male individuals with cardiovascular disease risks because of the excessive increase in blood pressure immediately after exercise. Exercise at 20 o'clock is more effective in improving wall shear stress but is accompanied by elevated arterial stiffness indices and pressure-strain elastic modulus. These results provide a scientific basis for healthy young men in choosing the time of exercise by exploring the common carotid artery elasticity and hemodynamic-related indices.
Humans ; Male ; Young Adult ; Exercise/physiology* ; Carotid Artery, Common/physiology* ; Hemodynamics/physiology* ; Vascular Stiffness/physiology* ; Elasticity ; Resistance Training ; Adult

Alveolar bone reconstruction simulation is an effective means for quantifying orthodontics, but currently, it is not possible to directly obtain human alveolar bone material models for simulation. This study introduces a prediction method for the equivalent shear modulus of three-dimensional random porous materials, integrating the first-order Ogden hyperelastic model to construct a computed tomography (CT) based porous hyperelastic Ogden model (CT-PHO) for human alveolar bone. Model parameters are derived by combining results from micro-CT, nanoindentation experiments, and uniaxial compression tests. Compared to previous predictive models, the CT-PHO model shows a lower root mean square error (RMSE) under all bone density conditions. Simulation results using the CT-PHO model parameters in uniaxial compression experiments demonstrate more accurate prediction of the mechanical behavior of alveolar bone under compression. Further prediction and validation with different individual human alveolar bone samples yield accurate results, confirming the generality of the CT-PHO model. The study suggests that the CT-PHO model proposed in this paper can estimate the material properties of human alveolar bone and may eventually be used for bone reconstruction simulations to guide clinical treatment.
Humans ; Tomography, X-Ray Computed/methods* ; Porosity ; Alveolar Process/physiology* ; Bone Density ; Computer Simulation ; Elasticity ; X-Ray Microtomography ; Stress, Mechanical ; Finite Element Analysis ; Models, Biological

Although metal blocks have been widely used for reconstructing uncontained tibial bone defects, the influence of their elastic modulus on the stability of tibial prosthesis fixation remains unclear. Based on this, a finite element model incorporating constrained condylar knee (CCK) prosthesis, tibia, and metal block was established. Considering the influence of the post-restraint structure of the prosthesis, the effects of variations in the elastic modulus of the block on the von Mises stress distribution in the tibia and the block, as well as on the micromotion at the bone-prosthesis fixation interface, were investigated. Results demonstrated that collision between the insert post and femoral prosthesis during tibial internal rotation increased tibial von Mises stress, significantly influencing the prediction of block elastic modulus variation. A decrease in the elastic modulus of the metal block resulted in increased von Mises stress in the proximal tibia, significantly reduced von Mises stress in the distal tibia, decreased von Mises stress of the block, and increased micromotion at the bone-prosthesis fixation interface. When the elastic modulus of the metal block fell below that of bone cement, inadequate block support substantially increased the risk of stress shielding in the distal tibia and fixation interface loosening. Therefore, this study recommends that biomechanical investigations of CCK prostheses must consider the post-constraint effect, and the elastic modulus of metal blocks for bone reconstruction should not be lower than 3 600 MPa.
Knee Prosthesis ; Humans ; Finite Element Analysis ; Tibia/surgery* ; Elastic Modulus ; Arthroplasty, Replacement, Knee/methods* ; Stress, Mechanical ; Metals ; Prosthesis Design ; Knee Joint/surgery* ; Biomechanical Phenomena

Stroke remains a leading cause of long-term disability worldwide, demanding extensive and often prolonged rehabilitation. This case report describes the recovery of Mr. Julio, a 60-year-old male, who suffered an ischemic stroke at age 58, resulting in left-sided hemiparesis and balance issues. Even with delays in formal rehabilitation, he made a remarkable recovery over nearly three years. This is because of his strong intrinsic motivation, sustained adherence to therapy, and family support. His symptoms included left-sided weakness, numbness, vertigo, vomiting, and critically high blood pressure. Crucially, his diagnosis was confirmed by MRI only three months later and formal physical therapy started only after six months. Treatment included an emergency TPA, blood pressure control, antiplatelets, and a sustained home- based physical therapy regimen. This case highlights how patient-driven factors can lead to significant recovery even in resource-limited settings, emphasizing the role of motivation and adherence in long-term stroke rehabilitation.

OBJECTIVE: To explore the correlation between mechanical power normalized to dynamic lung compliance (Cdyn-MP) and weaning outcomes and prognosis in mechanically ventilated patients. METHODS: A prospective, observational cohort study was conducted. Patients who underwent invasive mechanical ventilation (IMV) for more than 24 hours and used a T-tube ventilation strategy for extubation in the intensive care unit (ICU) of Lianyungang First People's Hospital and Lianyungang Second People's Hospital between January 2022 and December 2023 were enrolled. The collected data encompassed patients' baseline characteristics, primary causes of ICU admission, vital signs and laboratory indicators during the initial spontaneous breathing trial (SBT), respiratory mechanics parameters within the 4-hour period prior to the SBT, weaning outcomes and prognostic indicators. Mechanical power (MP) and Cdyn-MP were calculated using a simplified MP equation. Univariate and multivariate Logistic regression analyses were utilized to determine the independent risk factors associated with weaning failure in patients undergoing mechanical ventilation. Restricted cubic spline (RCS) analysis and Spearman rank-sum test were employed to investigate the correlation between Cdyn-MP and weaning outcomes as well as prognosis. Receiver operator characteristic curve (ROC curve) was constructed, and the area under the ROC curve (AUC) was computed to evaluate the predictive accuracy of Cdyn-MP for weaning outcomes in mechanically ventilated patients. RESULTS: A total of 366 patients undergoing IMV were enrolled in this study, with 243 cases classified as successful weaning and 123 cases classified as failed weaning. Among them, 23 patients underwent re-intubation within 48 hours after the successful withdrawal of the first SBT, non-invasive ventilation, or died. Compared with the successful weaning group, the patients in the failed weaning group had significantly increased levels of sequential organ failure assessment (SOFA) score, body temperature and respiratory rate (RR) during SBT, and respiratory mechanical parameters within the 4-hour period prior to the SBT [ventilation frequency, positive end-expiratory pressure (PEEP), platform pressure (Pplat), peak inspiratory pressure (Ppeak), dynamic driving pressure (ΔPaw), fraction of inspired oxygen (FiO₂), MP, and Cdyn-MP], dynamic lung compliance (Cdyn) was significantly reduced, and duration of IMV, ICU length of stay, and total length of hospital stay were significantly prolonged. However, there were no statistically significant differences in age, gender, body mass index (BMI), smoking history, main causes of ICU admission, other vital signs [heart rate (HR), mean arterial pressure (MAP), saturation of peripheral oxygen (SpO₂)] and laboratory indicators [white blood cell count (WBC), albumin (Alb), serum creatinine (SCr)] during SBT of patients between the two groups. Univariate Logistic regression analysis was conducted, and variables with P < 0.05 and no multicollinearity with Cdyn-MP were selected for inclusion in the multivariate Logistic regression model. The results demonstrated that SOFA score [odds ratio (OR) = 1.081, 95% confidence interval (95%CI) was 1.008-1.160, P = 0.030], and PEEP (OR = 1.191, 95%CI was 1.075-1.329, P = 0.001), FiO₂ (OR = 1.035, 95%CI was 1.006-1.068, P = 0.021) and Cdyn-MP (OR = 1.190, 95%CI was 1.086-1.309, P < 0.001) within the 4-hour period prior to the SBT were independent risk factors for weaning failure in patients undergoing IMV. The RCS analysis after adjusting for confounding factors showed that as Cdyn-MP within the 4-hour period prior to the SBT increased, the risk of weaning failure in patients undergoing IMV significantly increased (P < 0.001). The Spearman rank correlation test showed that Cdyn-MP within the 4-hour period prior to the SBT was positively correlated with respiratory mechanical parameters including ΔPaw and MP (r values were 0.773 and 0.865, both P < 0.01), and negatively correlated with Cdyn (r = -0.587, P < 0.01). Cdyn-MP within the 4-hour period prior to the SBT was positively correlated with prognostic indicators such as duration of IMV, length of ICU stay, and total length of hospital stay (r values were 0.295, 0.196, and 0.120, all P < 0.05). ROC curve analysis demonstrated that, within the 4-hour period preceding the SBT, Cdyn-MP, MP, Cdyn, and ΔPaw possessed predictive value for weaning failure in patients undergoing IMV. Notably, Cdyn-MP exhibited superior predictive capability, evidenced by an AUC of 0.761, with a 95%CI ranging from 0.712 to 0.810 (P < 0.001). At the optimal cut-off value of 408.5 J/min×cmH₂O/mL×10^-3, the sensitivity was 68.29%, and the specificity was 71.19%. CONCLUSION Cdyn-MP is related to weaning outcomes and prognosis in mechanically ventilated patients, and has good predictive ability in assessing the risk of weaning failure.
Humans ; Prospective Studies ; Ventilator Weaning ; Prognosis ; Respiration, Artificial ; Intensive Care Units ; Lung Compliance ; Female ; Male ; Middle Aged ; Aged