Minimally Invasive Pectus Excavatum Correction and Endoscopic Port Access Mitral Valve Surgery.

This case study describes the successful short-term outcome of staged minimally invasive pectus excavatum correction and endoscopic mitral valve repair in a patient with severe mitral valve regurgitation and pectus excavatum.

The influence of eye model parameter variations on simulated eye-tracking outcomes.

The simulated data used in eye-tracking-related research has been largely generated using normative eye models with little consideration of how the variations in eye biometry found in the population may influence eye-tracking outcomes. This study investigated the influence that variations in eye model parameters have on the ability of simulated data to predict real-world eye-tracking outcomes. The real-world experiments performed by two pertinent comparative studies were replicated in a simulated environment using a highcomplexity stochastic eye model that includes anatomically accurate distributions of eye biometry parameters. The outcomes showed that variations in anterior corneal asphericity significantly influence simulated eye-tracking outcomes of both interpolation and model-based gaze estimation algorithms. Other, more commonly varied parameters such as the corneal radius of curvature and foveal offset angle had little influence on simulated outcomes.

Circumflex Coronary Artery Injury during Modern Mitral Valve Surgery-A Review of Current Concepts and Perspectives.

The devastating impact of a circumflex coronary artery (CX) injury during mitral valve (MV) surgery is well reported. Despite significant improvements in preoperative risk assessment, intraoperative diagnosis and perioperative treatment strategies of CX injury during MV surgery, recent reports re-emphasize the variability in presentation, the unpredictable mechanisms of injury and the conflicting evidence regarding perioperative management. The progressive transition from conventional sternotomy access to minimally invasive surgical and transcatheter (TC) interventions for MV disease are associated with significant learning curves and require additional single-shaft and robotic console suture manipulation skills with special attentiveness to the potential risk of CX injury. The introduction of hybrid theatres that facilitate single stage surgical and TC interventions also provides new intraoperative diagnostic and therapeutic options without transporting unstable patients for percutaneous coronary intervention (PCI) assessment. By utilizing a MeSH terms-based PubMed search, a total of 89 patients with CX injury that occurred during MV surgery was identified from 49 reports between 1967 and 2022. MV surgery was performed by conventional sternotomy (n = 76, 85.4%), endoscopic (n = 12, 13.4%) and robotic access (n = 1, 1.1%), with 35 injuries (39.3%) resulting in total CX occlusion. Rescue PCI was utilized in 40 patients (44.9%). This manuscript provides a systematic overview of all available historic and contemporary reports on CX injury during MV surgery, outlines recent refinements in CX injury mechanisms, describes current MV surgery associated CX injury prevention and diagnosis and treatment strategies and highlights important MV procedural aspects that may minimize the risk and consequences of CX injury.

Reconstruction of the mandible from partial inputs for virtual surgery planning.

Statistical Shape Models (SSMs) and Sparse Prediction Models (SPMs) based on regressions between cephalometric measurements were compared against standard practice in virtual surgery planning for reconstruction of mandibular defects. Emphasis was placed on the ability of the models to reproduce clinically relevant metrics. CT scans of 50 men and 50 women were collected and split into training and testing datasets according to an 80:20 ratio. The scans were segmented, and anatomical landmarks were identified. SPMs were constructed based on direct regressions between measurements derived from the anatomical landmarks. SSMs were developed by establishing correspondence between the segmented meshes, performing alignment, and principal component analysis. Anterior and bilateral defects were simulated by removing sections of the mandibles in the testing set. Measurement errors after reconstruction ranged from 1.07˚ to 2.2˚ and 0.66 mm to 2.02 mm for mirroring, from 0.45˚ to 3.67˚ and 0.66 mm to 2.54 mm for the SSMs, and from 1.74˚ to 5.01˚ and 0.64 mm to 2.89 mm for the SPMs. Surface-to-surface errors ranged from 1.01 mm to 1.29 mm and 1.06 mm to 1.33 mm for mirroring and SSMs, respectively. Based on the results, SSMs are recommended for VSP in the absence of normal patient anatomy.

Estimation of Simulated Left Ventricle Elastance Using Lumped Parameter Modelling and Gradient-Based Optimization With Forward-Mode Automatic Differentiation Based on Synthetically Generated Noninvasive Data.

The present study evaluates a parameter discovery approach based on a lumped parameter model of the cardiovascular system in conjunction with optimization to approximate important cardiac parameters, including simulated left ventricle elastances. Important parameters pertaining to ventricular function were estimated using gradient optimization and synthetically generated measurements. Forward-mode automatic differentiation was used to estimate the cost function-parameter matrices and compared to the common finite differences approach. Synthetic data of healthy and diseased hearts were generated as proxies for noninvasive clinical measurements and used to evaluate the algorithm. Twelve parameters including left ventricle elastances were selected for optimization based on 99% explained variation in mean left ventricle pressure and volume. The hybrid optimization strategy yielded the best overall results compared to 1st order optimization with automatic differentiation and finite difference approaches, with mean absolute percentage errors ranging from 6.67% to 14.14%. Errors in left ventricle elastance estimates for simulated aortic stenosis and mitral regurgitation were smallest when including synthetic measurements for arterial pressure and valvular flow rate at approximately 2% and degraded to roughly 5% when including volume trends as well. However, the latter resulted in better tracking of the left ventricle pressure waveforms and may be considered when the necessary equipment is available.

Dynamic simulation of aortic valve stenosis using a lumped parameter cardiovascular system model with flow regime dependent valve pressure loss characteristics.

Valvular heart diseases are growing concern in impoverished parts of the world, such as Southern-Africa, claiming more than 31 % of total deaths related to cardiovascular diseases. The ability to model the effects of regurgitant and obstructive lesions on the valve body can assist clinicians in preparing personalised treatments. In the present work, a multi-compartment lumped parameter model of the human cardiovascular system is developed, with a newly proposed valve modelling approach which accounts for geometry and flow regime dependent pressure drops along with the valve cusp motion. The model is applied to study various degrees of aortic stenosis using typical human cardiovascular parameters. The predicted transvalvular pressure drops for the different modelling approaches are compared to typical measured mean and peak gradients found in literature for severely stenosed aortic valves. The comparison between the predicted and measured values show that the previously published valve models under predicts expected severely stenosed peak and mean transvalvular pressure drops by approximately 47% and 25% respectively, whereas the newly proposed model under predicts the peak pressure drop by 25% and over predicts mean pressure drop by 7%.

Model Construction for the Estimation of Healthy Bone Shape and Density Distribution.

Statistical models are widely used within biomedical fields for automated segmentation and reconstruction of healthy geometry. In the absence of contralateral geometry, statistical models are a viable alternative for reconstructing healthy bone anatomy. Therefore, statistical models of shape and appearance were constructed from sample data based on the right femur of South African males, and their use in an automated segmentation and density estimation application was investigated. The models reproduced the shape and density distribution of the population with an average error of 1.3 mm and a 90% density fit. These results fall within the acceptable tolerance limits of reconstructive surgery and appear promising for practical use in implant design.Clinical Relevance- Constructing and validating statistical models and registration algorithms provides the groundwork for further investigation into automating the digital reconstruction of pathological bone for use in implant design.

Minimally invasive surgical and transcatheter interventions for aortic valve incompetence: current concepts and future perspectives.

We are currently witnessing rapid evolution in minimally invasive surgical (MI-AVS) and transcatheter (TAVR) techniques and innovations for the treatment of aortic valve disease. Current TAVR technology approved for the treatment of aortic valve stenosis do not consistently perform favorably in non-calcified aortic valve regurgitation (AR). Surgical aortic valve repair (AVr) by conventional midline sternotomy is generally accepted as the contemporary "gold standard" intervention, while prosthetic aortic valve replacement and the well-known Ross procedure as a biological alternative to AVr, are reserved for patients who are at risk of early repair failure. AVr offers potential benefits over prosthetic replacement in younger patients with contraindications to long term anticoagulation and life-expectancies greater than the expected structural prosthetic valve degeneration. Even though excellent AVr outcomes are achieved in high-volume expert centers, it is generally regarded to be technically challenging, have significant learning curves and is subsequently infrequently performed by inexperienced surgeons. However, MI-AVS is now the routine approach for isolated aortic valve surgery in various cardiac centers and reports that describe minimally invasive AVr outcomes are progressively emerging. This article outlines the current role and future perspectives of contemporary AR repair techniques by MI-AVS and describes the ongoing evolution of exciting TAVR technology designed specifically for the treatment of non-calcified AR.

Quality of recovery after total hip and knee arthroplasty in South Africa: a national prospective observational cohort study.

BACKGROUND: Encouraged by the widespread adoption of enhanced recovery protocols (ERPs) for elective total hip and knee arthroplasty (THA/TKA) in high-income countries, our nationwide multidisciplinary research group first performed a Delphi study to establish the framework for a unified ERP for THA/TKA in South Africa. The objectives of this second phase of changing practice were to document quality of patient recovery, record patient characteristics and audit standard perioperative practice. METHODS: From May to December 2018, nine South African public hospitals conducted a 10-week prospective observational study of patients undergoing THA/TKA. The primary outcome was 'days alive and at home up to 30 days after surgery' (DAH30) as a patient-centred measure of quality of recovery incorporating early death, hospital length of stay (LOS), discharge destination and readmission during the first 30 days after surgery. Preoperative patient characteristics and perioperative care were documented to audit practice. RESULTS: Twenty-one (10.1%) out of 207 enrolled patients had their surgery cancelled or postponed resulting in 186 study patients. No fatalities were recorded, median LOS was 4 (inter-quartile-range (IQR), 3-5) days and 30-day readmission rate was 3.8%, leading to a median DAH30 of 26 (25-27) days. Forty patients (21.5%) had pre-existing anaemia and 24 (12.9%) were morbidly obese. In the preoperative period, standard care involved assessment in an optimisation clinic, multidisciplinary education and full-body antiseptic wash for 67 (36.2%), 74 (40.0%) and 55 (30.1%) patients, respectively. On the first postoperative day, out-of-bed mobilisation was achieved by 69 (38.1%) patients while multimodal analgesic regimens (paracetamol and Non-Steroid-Anti-Inflammatory-Drugs) were administered to 29 patients (16.0%). CONCLUSION: Quality of recovery measured by a median DAH30 of 26 days justifies performance of THA/TKA in South African public hospitals. That said, perioperative practice, including optimisation of modifiable risk factors, lacked standardisation suggesting that quality of patient care and postoperative recovery may improve with implementation of ERP principles. Notwithstanding the limited resources available, we anticipate that a change of practice for THA/TKA is feasible if 'buy-in' from the involved multidisciplinary units is obtained in the next phase of our nationwide ERP initiative. TRIAL REGISTRATION: The study was registered with ClinicalTrials.gov ( NCT03540667 ).

Reasons for Conversion and Adverse Intraoperative Events in Robotically Enhanced Minimally Invasive Coronary Artery Revascularization.

OBJECTIVE: The transition from sternotomy access to minimally invasive coronary artery bypass grafting is associated with steep learning curves. This study reports the reasons for sternotomy conversions from robotically enhanced minimally invasive direct coronary artery bypass grafting (RE-MIDCAB) and describes potential risk reduction strategies. METHODS: The perioperative data of 759 RE-MIDCAB patients (mean age 65.9 ± 10 years, 25.5% female, 30.2% multivessel disease) operated between July 1, 2002 and November 30, 2018 were reviewed for the reasons of conversion and adverse intraoperative events. Hybrid revascularization was planned in 204 (26.9%) patients. RESULTS: Sternotomy conversion occurred in 30 (4.0%) patients. Lung adhesions and unsuccessful single-lung ventilation prohibited safe RE-MIDCAB internal thoracic artery (ITA) harvesting in 11 (36.7%) and 1 (3.3%) patients, respectively. ITA dysfunction (n = 11, 36.7%) and inadequate target vessel visualization (n = 3, 10.0%) were among the anatomical reasons for conversions. Adverse intraoperative events included ventricle perforation (n = 1, 3.3%) and sustained ventricular arrhythmia (n = 1, 3.3%). The in-hospital mortality and mean length of hospitalization for sternotomy conversion were 3.3% (n = 1 of 30) and 13.4 ± 14.5 days, respectively. Perioperative morbidities included pneumonia (n = 4, 13.3%). Premorbid renal dysfunction predicted sternotomy conversion at the 5% level of significance. CONCLUSIONS: RE-MIDCAB provides an attractive surgical platform for primary- or hybrid coronary artery procedures. The progressive increase in patient risk profiles, strict quality control, and focus on clinical governance require awareness of reasons that potentially contribute RE-MIDCAB to sternotomy conversion to ensure safe and sustainable programs.

Variability, agreement and reliability of MRI knee landmarks.

Surface mesh reconstructions of bones are often required to define landmark-based coordinate systems, regions of interest and morphological features when studying the soft tissues of the knee from MRI scans. This study reports the variability, agreement and reliability of osseous landmarks to better understand their downstream effects. Fifteen landmarks were defined on the distal femur and twelve on the proximal tibia. Surface meshes were created from twenty right knee MRI scans with a mean subject age of 30.9 years. A single observer identified landmarks on all twenty knees, while three observers repeated the observations three times on a subset of eight knees. All observations were aligned to the Procrustes mean shapes. Principal component analysis was used to study inter-subject variability and two-way ANOVA for inter- and intra-observer agreement and reliability. Inter-subject landmark variation ranged from 0.6 to 5.26 mm, while inter- and intra-observer agreement were at most 5.1 and 5.69 mm respectively. Between-observer reliability ranged from 0.07 to 0.98 while within-observer values were between 0.51 and 0.98. Landmarks derived from fitted spheres or circles often performed well, while most others had their poorest agreement or greatest variation limited to only one or two cardinal directions.

Estimating regions of interest on the distal femur.

We investigated the ability of a statistical shape model to estimate unknown regions of interest related to patient-specific unicompartmental knee replacement design on the distal femur. Generality ranged between 0.67 and 1.03 mm, specificity from 0.79 to 1.07 mm, and leave-one-out root mean square estimation errors from 0.88 to 1.27 mm for different regions. Moderate to strong correlations were established between ground truths and model estimates for local morphological measurements on the medial and lateral condyles. Results compared well to similar studies in the literature, and we conclude that shape models might prove useful during patient-specific unicompartmental knee replacement design.

Endoscopic Port AccessTM left ventricle outflow tract resection and atrioventricular valve surgery.

The continuous evolution in robotic-, endoscopic- and trans-catheter cardiac interventions resulted in innovative techniques that simultaneously address left ventricular outflow tract obstruction (LVOTO) and concomitant atrioventricular valve (AVV) pathology in the context of hypertrophic obstructive cardiomyopathy (HOCM). We present our brief report of 13 consecutive HOCM patients with concomitant AVV disease, who underwent endoscopic left ventricular septal myomectomy (LVSM) and AVV surgery by Endoscopic Port AccessTM Surgery (EPAS) between March 1st 2010 and October 31st 2015. Our EPAS technique in the context of HOCM utilizes peripheral cardiopulmonary bypass, endo-aortic balloon occlusion and a 4-cm right antero-lateral thoracic working port. Access to the LVOTO is obtained by detaching the anterior mitral valve (MV) leaflet from the annulus. Controlled sharp LVSM is then performed from the aortic leaflet base to the papillary muscles. Subsequent routine AVV surgery is performed using long shafted instruments. There were no sternotomy conversions, LVSM complications or 30-day mortalities. The mean length of hospitalization was 17.7±18.1 days. Long-term clinical and echocardiographic analysis of 645.7 patient-months (n=13, 100.0% complete) identified two late mortalities, which were not procedure-, HOCM- or AVV-related. All patients (n=13, 100.0%), including the late mortalities, had significant improvement in their quality of life, a 100% long-term freedom from re-intervention and no residual peak instantaneous LVOTO gradients more than 15 mmHg. This brief report emphasises that simultaneous LVSM and concomitant AVV surgery by EPAS can safely be performed in experienced centres with favourable long-term outcomes.

Endoscopic port access surgery for isolated atrioventricular valve endocarditis.

OBJECTIVES: Our goal was to report the clinical and echocardiographic outcomes of endoscopic port access surgery for isolated active and convalescent atrioventricular valve endocarditis (AVVE). METHODS: Our current surgical team performed endoscopic port access surgery in 66 consecutive patients with isolated AVVE (mean age, 65.5 ± 12.7 years, 37.9% women, mean EuroSCORE II 31.2 ± 24.9%, 45.5% prosthetic AVVE, Staphylococcus aureus 22.2%), between 1 May 2004 and 31 July 2015. Isolated mitral valve endocarditis was present in 53 (80.4%) patients, including 11 (16.7%) with periannular abscesses. RESULTS: Procedures performed included mitral valve repair (n = 15, 22.7%) and left ventricular septal myomectomy (n = 1, 1.5%). Reasons for sternotomy conversion (n = 6, 9.1%) included lung adhesions (n = 3, 4.5%). The mean cardiopulmonary bypass and ischaemic times were 167.2 ±48.7 and 112.6 ± 33.3 min, respectively. In-hospital morbidities included revision for bleeding (n = 6, 9.1%). The 30-day survival rate was 87.9%. Causes of in-hospital deaths (n = 12) included low cardiac output syndrome (n = 3, 4.5%). Age, critical preoperative status and EuroSCORE II score predicted deaths individually at the 5% level of significance. The Kaplan-Meier analyses (mean 63.2 ± 42.5 months) for survival and freedom from AVVE reintervention at 10 years were 69.4% and 98.4%, respectively. Of the mid-term survivors (n = 50, 93.9% complete), 94.0% (n = 47) classified as New York Heart Association (NYHA) II or less with no mitral valve regurgitation greater than Grade I. CONCLUSIONS: Complex atrioventricular valve surgery in the context of AVVE can be endoscopically performed in experienced centres and should not deter surgeons from offering patients with AVVE the potential benefits of minimally invasive cardiac surgery.

Reasons for conversion and adverse intraoperative events in Endoscopic Port Access™ atrioventricular valve surgery and minimally invasive aortic valve surgery.

OBJECTIVES: This study reports the factors that contribute to sternotomy conversions (SCs) and adverse intraoperative events in minimally invasive aortic valve surgery (MI-AVS) and minimally invasive Endoscopic Port Access™ atrioventricular valve surgery (MI-PAS). METHODS: In total, 3780 consecutive patients with either aortic valve disease or atrioventricular valve disease underwent minimally invasive valve surgery (MIVS) at our institution between 1 February 1997 and 31 March 2016. MI-AVS was performed in 908 patients (mean age 69.2 ± 11.3 years, 45.2% women, 6.2% redo cardiac surgery) and MI-PAS in 2872 patients (mean age 64.1 ± 13.3 years, 46.7% women, 12.2% redo cardiac surgery). RESULTS: A cumulative total of 4415 MIVS procedures (MI-AVS = 908, MI-PAS = 3507) included 1537 valve replacements (MI-AVS = 896, MI-PAS = 641) and 2878 isolated or combined valve repairs (MI-AVS = 12, MI-PAS = 2866). SC was required in 3.0% (n = 114 of 3780) of MIVS patients, which occurred in 3.1% (n = 28 of 908) of MI-AVS patients and 3.0% (n = 86 of 2872) of MI-PAS patients, respectively. Reasons for SC in MI-AVS included inadequate visualization (n = 4, 0.4%) and arterial cannulation difficulty (n = 7, 0.8%). For MI-PAS, SC was required in 54 (2.5%) isolated mitral valve procedures (n = 2183). Factors that contributed to SC in MI-PAS included lung adhesions (n = 35, 1.2%), inadequate visualization (n = 2, 0.1%), ventricular bleeding (n = 3, 0.1%) and atrioventricular dehiscence (n = 5, 0.2%). Neurological deficit occurred in 1 (0.1%) and 3 (3.5%) MI-AVS and MI-PAS conversions, respectively. No operative or 30-day mortalities were observed in MI-AVS conversions (n = 28). The 30-day mortality associated with SC in MI-PAS (n = 86) was 10.5% (n = 9). CONCLUSIONS: MIVS is increasingly being recognized as the 'gold-standard' for surgical valve interventions in the context of rapidly expanding catheter-based technology and increasing patient expectations. Surgeons need to be aware of factors that contribute to SC and adverse intraoperative outcomes to ensure that patients enjoy the maximum potential benefit of MIVS and to apply effective risk reduction strategies that encourage safer and sustainable MIVS programmes.

Mitral Valve Replacement-Current and Future Perspectives.

The favorable outcomes achieved with modern mitral valve repair techniques redefined the role of mitral valve replacement. Various international databases report a significant decrease in replacement procedures performed compared with repairs, and contemporary guidelines limit the application of surgical mitral valve replacement to pathology in which durable repair is unlikely to be achieved. The progressive paradigm shift toward endoscopic and robotic mitral valve surgery is also paralleled by rapid developments in transcatheter devices, which is progressively expanding from experimental approaches to becoming clinical reality. This article outlines the current role and future perspectives of contemporary surgical mitral valve replacement within the context of mitral valve repair and the dynamic evolution of exciting transcatheter alternatives.

Endoscopic Port Access Surgery for Late Orthotopic Cardiac Transplantation Atrioventricular Valve Disease.

BACKGROUND: The study aim was to present details of the perioperative and long-term outcomes of redo-endoscopic port access surgery (REPAS) for late atrioventricular valve disease (AVVD) in orthotopic cardiac transplant (OCT) patients. METHODS: Between February 2004 and October 2015, REPAS was performed for late AVVD in seven consecutive OCT patients (mean age 57.9 ± 17.2 years; EuroSCORE II 21.2 ± 14.7%) at the authors' institution. The mean OCT-REPAS time interval was 7.8 ± 4.6 years (range: 1.3-13.8 years). NYHA class III or IV symptoms were present in four patients (57%). The mean left ventricular ejection fraction was 52.9 ± 3.9%, and surgical indications included severe mitral valve (MV) and tricuspid valve (TV) regurgitation in three patients (44%) and six patients (86%), respectively. Etiological factors included endomyocardial biopsy trauma (n = 6; 86%), degenerative disease (n = 2; 29%), and fungal endocarditis (n = 1; 14%). RESULTS: Procedures performed included MV repair (n = 3; 43%) and TV replacement (n = 3; 43%). There were no sternotomy conversions or revisions for any cause. The mean cardiopulmonary bypass and ischemic times were 178.4 ± 48.6 min and 118.3 ± 39.5 min, respectively. In-hospital morbidities included hospital-acquired pneumonia (n = 2; 29%). There were no wound infections or 30-day mortalities. The mean duration of hospitalization was 18.3 ± 11.0 days. A mean of 29.2 ± 45.6 patient-months (total 204.3 patient-months) was available for long-term clinical and echocardiographic analysis (n = 7; 100% complete). No MV or TV reinterventions were required. NYHA class ≤II was achieved in five patients (71%). No patient presented with residual MV regurgitation greater than grade I. CONCLUSIONS: REPAS for late AVVD in OCT patients is a safe and durable procedure with favorable technique-related mortality, in-hospital morbidity, and long-term cardiac-specific outcomes at experienced centers. The present technique provided an attractive benchmark against which emerging percutaneous interventions may be measured, and earlier referral of patients should be considered.

Total Percutaneous Cardiopulmonary Bypass for Robotic and Endoscopic Atrioventricular Valve Surgery.

Continuous technological advances in endoscopic-, robotic- and catheter-based cardiac interventions are paralleled by rapid evolution in cannulation strategies for circulatory support. The recent introduction of suture-based percutaneous vascular closure devices resulted in innovative strategies to deliver peripheral endovascular therapeutic devices through the iliac and femoral arteries. Percutaneous access allows rapid postoperative mobilization and potentially avoids the devastating neuro-lympho-vascular- and wound infection morbidities associated with conventional open surgical exposure. We routinely perform endoscopic port access surgery for all isolated atrioventricular valve pathology and extended the application of suture-based percutaneous vascular closure device to establish total percutaneous peripheral cardiopulmonary bypass in disabled, immune-suppressed, and morbidly obese patients at risk neuro-lympho-vascular- and wound infection. In this report, we provide a stepwise description of our total percutaneous peripheral cardiopulmonary bypass technique.