Design and In Vitro Validation of an Orthopaedic Drill Guide for Femoral Stem Revision in Total Hip Arthroplasty.

OBJECTIVE: Cemented total hip arthroplasty (THA) demonstrates superior survival rates compared to uncemented procedures. Nevertheless, most younger patients opt for uncemented THA, as removing well-fixed bone cement in the femur during revisions is complex, particularly the distal cement plug. This removal procedure often increases the risk of femoral fracture or perforation, haemorrhage and weakening bone due to poor drill control and positioning. Aim of this study was to design a novel drill guide to improve drill positioning. METHODS AND PROCEDURES: A novel orthopaedic drill guide was developed, featuring a compliant centralizer activated by a drill guide actuator. Bone models were prepared to assess centralizing performance. Three conditions were tested: drilling without guidance, guided drilling with centralizer activation held, and guided drilling with centralizer activation released. Deviations from the bone centre were measured at the entry and exit point of the drill. RESULTS: In the centralizing performance test, the drill guide significantly reduced drill hole deviations in both entry and exit points compared to the control ([Formula: see text]). The absolute deviation on the exit side of the cement plug was 10.59mm (SD 1.56) for the 'No drill guide' condition, 3.02mm (SD 2.09) for 'Drill guide - hold' and 2.12mm (SD 1.71) for 'Drill guide - release'. The compliant drill guide centralizer significantly lowered the risk of cortical bone perforation during intramedullary canal drilling in the bone models due to better control of the cement drill position. Clinical and Translational Impact Statement: The drill guide potentially reduces perioperative risks in cemented femoral stem revision. Future research should identify optimal scenarios for its application.

Reprocessing Zamak laryngoscope blades into new instrument parts; an 'all-in-one' experimental study.

Introduction: Disposable instruments in healthcare have led to a significant increase of medical waste. The aim of this study is to validate the recycling of disposable Zamak laryngoscope blades into new medical components by using a new 'all-in-one' affordable reprocessing setup as alternative for die-casting. Methods: A n "all-in-one" casting set-up was designed and built. Laryngoscope blades, recovered from two hospitals, were disinfected, melted and cast into dog-bones and into new instrument parts. The quality of the cast material was evaluated using X-ray fluorescence spectrometry. The mechanical properties were obtained by assessing the Ultimate Tensile Strength (UTS) and tensile tests. Results: A recovery of 93 % Zamak was obtained using a melting temperature of 420 °C for 3 h. The XRF Spectro data showed higher Zinc and silicon concentrations when compared with Virgin Zamak. The dog-bones tests resulted in an average UTS, Yield Strength (YS) and Young's Modulus (YM) of 236 ± 61 (MPa), 70 ± 43 and 9 ± 3, respectively, representing 82 %, 103 % and 64 % of the UTS, YS and YM of standard Zamak. Functional instrument parts with extensions and inner chambers were cast with a maximal shrinkage percentage of 1 ± 1 %. Discussion: This study demonstrates that the created "all-in-one" reprocessing method can process contaminated disposable Zamak laryngoscope blades into new raw base material and new instrument parts. Although material and surface properties can deteriorate, reprocessed Zamak still has sufficient mechanical properties and can be used to cast complex parts with sufficient dimensional tolerances and minimal shrinkage. Conclusion: A micro reprocessing method was designed and used to turn disposed laryngoscope blades into new basis material and semi-finished components. Follow up studies are needed to scale and optimize this process towards a functional alternative for die casting. It should be further investigated how this process can contribute to further medical waste reduction and a circular healthcare economy.

Single center experience in the treatment of hemodynamically significant diffuse coronary artery disease of the left anterior descending.

INTRODUCTION: To date there are no recommendations on how to treat patients with an FFR positive but diffusely diseased left anterior descending coronary artery (LAD). Benefit of coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI) is not so evident due to doubts regarding longevity and patency. METHODS: This retrospective single-center study assessed clinical outcomes in patients presenting with symptomatic single vessel coronary artery disease of a diffusely diseased, hemodynamically significant LAD treated by coronary artery bypass grafting (CABG) or optimal medical therapy (OMT) between 2015 and 2020. Primary outcome of this study was the composite endpoint of all-cause mortality, myocardial infarction and repeat revascularization during 2-year follow-up. Secondary endpoints consisted of the individual components of the primary endpoint. Change in angina severity grade based on the Canadian Cardiovascular Society (CCS) class between baseline and 2-year follow-up was assessed. RESULTS: Fifty-nine patients were included of which 25 patients underwent CABG and 34 patients were treated by OMT. There was a statistically significant difference in FFR value at baseline between the treatment groups (CABG 0.70 ± 0.04; OMT 0.75 ± 0.04; p < 0.001). After 2-year follow-up, there were no statistically significant differences with regard to the primary endpoint (CABG 16% (n = 4); OMT 17.6% (n = 6); p = 1.00) and secondary endpoints between the groups over 2-year follow-up. CONCLUSION: In patients with hemodynamically significant diffuse single vessel coronary artery disease of the left anterior descending, there was no difference between OMT and CABG in terms of mortality, myocardial infarction, revascularization and symptom reduction after two years of follow-up.

Sex Difference in Long-Term Survival After Coronary Artery Bypass Grafting Is Age-Dependent.

OBJECTIVES: Women undergoing coronary artery bypass grafting (CABG) demonstrate higher rates of postoperative morbidity and mortality than men. The aim of this study was to compare the patient profile and long-term outcomes of men and women undergoing isolated CABG. DESIGN: A retrospective patient record study and propensity score-matched analysis. SETTING: This single-center study was performed at Catharina Hospital in Eindhoven, The Netherlands. PARTICIPANTS: The study comprised 17,483 patients, of whom 13,564 (77.6%) were men and 3,919 (22.4%) were women. INTERVENTIONS: Coronary artery bypass grafting was performed between January 1998 and December 2015. MEASUREMENTS AND MAIN RESULTS: The mean follow-up period was 8.8 ± 5.0 years. Women were older than men (67.7 ± 9.4 years v 63.9 ± 9.6 years, p < 0.001) and had lower preoperative hemoglobin levels. Early mortality (30-day) (2.8% v 1.9%; p < 0.001) and one-year mortality (5.2% v 3.8%; p < 0.001) rates were significantly higher in women than in men. Women demonstrated worse long-term survival than men only in the population younger than 70 years. After propensity score matching, female sex was not identified as an independent risk factor for long-term survival. CONCLUSIONS: In the patient population, propensity score-matched analysis showed that female sex was not an independent risk factor for long-term survival after CABG. Poorer survival in women after CABG only was observed in patients <70 years of age.

Diagnostic performance of echocardiography to predict cardiac tamponade after cardiac surgery.

OBJECTIVES: Cardiac tamponade is a life-threatening complication after cardiac surgery. Echocardiography, both transthoracic (TTE) and transesophageal (TEE), may help to identify cardiac tamponade after surgery, but its diagnostic value remains unverified after cardiac surgery. METHODS: This retrospective single-centre cohort study used the electronic medical record and echocardiography database of the Catharina Hospital Eindhoven, a tertiary referral cardiothoracic centre, to identify patients who received echocardiography because they were clinically suspected of having cardiac tamponade within the 4 weeks after cardiac surgery. Overall diagnostic accuracy of both TTE and TEE was calculated (sensitivity, specificity, positive predictive value, negative predictive value, and receiver operation characteristics curves). Subgroup analyses were performed based on the timing of the echocardiography after primary surgery (<24, 24-72, >72 h). RESULTS: The query identified 427 echocardiographs, 373 TTEs and 54 TEEs, being performed in 414 patients (65% males, mean age 67 years). Of them, 116 patients underwent surgical re-exploration in which a cardiac tamponade was determined in 105 patients with a 30-day mortality of 8.6%. The area under the receiver operation characteristics curve for echocardiography in the 4 weeks after cardiac surgery was 0.78 [95% confidence interval (CI): 0.72-0.84, P < 0.001]. In the first 24 h after surgery was the positive predictive value of echocardiography 58.3% (95% CI: 28.6-83.5) with an area under the curve of 0.64 (95% CI: 0.49-0.80, P = 0.06). The diagnostic accuracy improved over time for both TTE and TEE. CONCLUSIONS: Diagnostic accuracy of echocardiography in the 4 weeks after cardiac surgery for cardiac tamponade is acceptable and improves over time. However, in the early postoperative phase (<24 h), the diagnostic accuracy of echocardiography is poor.

A life cycle assessment of reprocessing face masks during the Covid-19 pandemic.

The Covid-19 pandemic led to threatening shortages in healthcare of medical products such as face masks. Due to this major impact on our healthcare society an initiative was conducted between March and July 2020 for reprocessing of face masks from 19 different hospitals. This exceptional opportunity was used to study the costs impact and the carbon footprint of reprocessed face masks relative to new disposable face masks. The aim of this study is to conduct a Life Cycle Assessment (LCA) to assess and compare the climate change impact of disposed versus reprocessed face masks. In total 18.166 high quality medical FFP2 face masks were reprocessed through steam sterilization between March and July 2020. Greenhouse gas emissions during production, transport, sterilization and end-of-life processes were assessed. The background life cycle inventory data were retrieved from the ecoinvent database. The life cycle impact assessment method ReCiPe was used to translate emissions into climate change impact. The cost analysis is based on actual sterilization as well as associated costs compared to the prices of new disposable face masks. A Monte Carlo sampling was used to propagate the uncertainty of different inputs to the LCA results. The carbon footprint appears to be 58% lower for face masks which were reused for five times compared to new face masks which were used for one time only. The sensitivity analysis indicated that the loading capacity of the autoclave and rejection rate of face masks has a large influence on the carbon footprint. The estimated cost price of a reprocessed mask was €1.40 against €1.55. The Life Cycle Assessment demonstrates that reprocessed FFP2 face masks from a circular economy perspective have a lower climate change impact on the carbon footprint than new face masks. For policymakers it is important to realize that the carbon footprint of medical products such as face masks may be reduced by means of circular economy strategies. This study demonstrated a lower climate change impact and lower costs when reprocessing and reusing disposable face masks for five times. Therefore, this study may serve as an inspiration for investigating reprocessing of other medical products that may become scarce. Finally, this study advocates that circular design engineering principles should be taken into account when designing medical devices. This will lead to more sustainable products that have a lower carbon footprint and may be manufactured at lower costs.

A novel Veress needle mechanism that reduces overshooting after puncturing the abdominal wall.

BACKGROUND: Complications that occur in laparoscopic surgery are often associated with the initial entry into the peritoneal cavity. The literature reported incidences of Veress needle (VN) injuries of e.g. 0.31% and 0.23%. In a 2010 national survey of laparoscopic entry techniques in the Canadian General Surgical practice, 57.3% of respondents had either experienced or witnessed a serious laparoscopic entry complication like bowel perforation and vascular injury. As those complications are potentially life threatening and should be avoided at all costs, improving safety of this initial action is paramount. METHODS: Based on a bare minimum design approach with focus on function expansion of existing components, a new Safety mechanism was developed for the VN that decreases the risks of VN overshooting. The mechanism works by preventing the puncturing acceleration of the tip of the VN by decoupling the surgeon's hand from the VN immediately after entering the abdomen. RESULTS: Based on a set of requirements, a first prototype of the VN+ with force decoupling safety mechanism is presented and evaluated on an ex vivo porcine abdominal wall tissue model in a custom setup. The experiments conducted by two novices and one experienced surgeon indicated a significant difference between the attempts with a standard, conventional working VN (41.4 mm [37.5-45 mm]) and VN+ with decoupling mechanism (20.8 mm [17.5-22.5 mm]) of p < 0.001. CONCLUSION: A new decoupling safety mechanism was integrated successfully in a standard VN resulting in a VN+ . The results from the pilot study indicate that this new VN+ reduces overshooting with a minimum of 50% in a standardised ex vivo setting on fresh porcine abdominal wall specimens.

The impact of surgical aortic valve replacement on quality of life-a multicenter study.

OBJECTIVES: To explore the effect of surgical aortic valve replacement on quality of life and the variance with age, particularly in patients at risk of deterioration. METHODS: In an observational, multicenter, cohort study of routinely collected health data, patients undergoing and electively operated between January 2011 and January 2015 with pre- and postoperative quality of life data were included. Patients were classified into 3 age groups: <65, 65-79, and ≥80 years. Quality of life was measured at baseline and at 1-year follow-up using the Short-Form Health Survey-12 or SF-36. We defined a >5-point difference as a minimal clinically important difference. Multivariable linear regression analysis, with adjustment for confounders, was used to evaluate the association between age and quality of life. RESULTS: In 899 patients, mean physical health increased from 55 to 66 and mental health from 60 to 66. A minimal clinically important decreased physical health was observed in 12% of patients aged <65 years, 16% of patients aged 65-79 years, and 22% of patients aged ≥80 years (P = .023). A decreased mental health was observed in 15% of patients aged <65 years, 22% of patients aged 65-79 years, and 24% aged ≥80 years (P = .030). Older age and a greater physical and mental score at baseline were associated with a decreased physical and mental quality of life (P < .001). CONCLUSIONS: Patients surviving surgical aortic valve replacement on average improve in physical and mental quality of life; nonetheless, with increasing age patients are at higher risk of experiencing a deterioration.

Reprocessing filtering facepiece respirators in primary care using medical autoclave: prospective, bench-to-bedside, single-centre study.

OBJECTIVE: There are widespread shortages of personal protective equipment as a result of the COVID-19 pandemic. Reprocessing filtering facepiece particle (FFP)-type respirators may provide an alternative solution in keeping healthcare professionals safe. DESIGN: Prospective, bench-to-bedside. SETTING: A primary care-based study using FFP-2 respirators without exhalation valve (3M Aura 1862+ (20 samples), Maco Pharma ZZM002 (14 samples)), FFP-2 respirators with valve (3M Aura 9322+ (six samples) and San Huei 2920V (16 samples)) and valved FFP type 3 respirators (Safe Worker 1016 (10 samples)). INTERVENTIONS: All masks were reprocessed using a medical autoclave (17 min at 121°C with 34 min total cycle time) and subsequently tested up to three times whether these respirators retained their integrity (seal check and pressure drop) and ability to filter small particles (0.3-5.0 µm) in the laboratory using a particle penetration test. RESULTS: We tested 33 respirators and 66 samples for filter capacity. All FFP-2 respirators retained their shape, whereas half of the decontaminated FFP-3 respirators showed deformities and failed the seal check. The filtering capacity of the 3M Aura 1862 was best retained after one, two and three decontamination cycles (0.3 µm: 99.3%±0.3% (new) vs 97.0±1.3, 94.2±1.3% or 94.4±1.6; p<0.001). Of the other FFP-2 respirators, the San Huei 2920 V had 95.5%±0.7% at baseline vs 92.3%±1.7% vs 90.0±0.7 after one-time and two-time decontaminations, respectively (p<0.001). The tested FFP-3 respirator (Safe Worker 1016) had a filter capacity of 96.5%±0.7% at baseline and 60.3%±5.7% after one-time decontamination (p<0.001). Breathing and pressure resistance tests indicated no relevant pressure changes between respirators that were used once, twice or thrice. CONCLUSION: This small single-centre study shows that selected FFP-2 respirators may be reprocessed for use in primary care, as the tested masks retain their shape, ability to retain particles and breathing comfort after decontamination using a medical autoclave.

Predictive value of great saphenous vein mapping prior to endoscopic harvesting in coronary artery bypass surgery.

OBJECTIVES: The use of endoscopic vein harvesting in patients undergoing coronary artery bypass grafting is increasing, often using bedside mapping. However, data on the predictive value of great saphenous vein (GSV) mapping are scarce. This study assessed whether preoperative mapping could predict final conduit diameter. METHODS: A prospective registry was created that included 251 patients. Saphenous vein mapping was performed prior to endoscopic vein harvesting at 3 predetermined sites. After harvesting and preparing the GSV, the outer diameters were measured. Appropriate graft size was defined as an outer diameter between 3 and 6 mm. RESULTS: A total of 753 GSV segments were analysed. The average mapping diameter was 3.2 ± 0.7 mm. The harvested GSV had a mean diameter of 4.7 ± 0.8 mm. Mapping diameters were significantly positively correlated with actual GSV diameters (correlation coefficient, 0.47; P < 0.001). If the preoperative mapping diameters were between 1.5 and 5 mm, 96.6% of the GSVs had suitable dimensions after endoscopic vein harvesting. CONCLUSIONS: Preoperative bedside mapping moderately predicts final GSV size after endoscopic harvesting but could not detect unsuitable vein segments. However, the majority of endoscopically harvested GSVs had diameters suitable to be used as coronary bypass grafts.

Preventing spasm of the radial artery conduit during coronary artery bypass grafting: Nicardipine versus verapamil.

BACKGROUND AND AIM OF THE STUDY: In vitro studies have shown a reduction in radial artery spasm with the use of calcium antagonists. The purpose of this study was to evaluate the efficacy of topical treatment of the radial artery conduit using either verapamil or nicardipine before the anastomoses. METHODS: This prospective randomized study included 131 patients, who underwent coronary artery bypass grafting surgery with the use of the radial artery as a conduit. In 65 patients, the harvested radial artery was topically treated with verapamil and in 66 patients with nicardipine. After harvesting the radial artery, the direct flow through the conduit was measured in vitro before 5-minute incubation in nicardipine or verapamil and measured again after incubation. The flow before and after incubation was compared. Postincubation flow was also compared in the two groups. After performing the anastomosis, the flow through the radial artery was measured in vivo. RESULTS: The mean flow after NaCl incubation was 19.93 ± 12.66 mL/min and after incubation in the Ca+ channel blocker 47.16 ± 14.58 mL/min (P < .001). No significant difference in postincubation free flow was found between verapamil (46.29 ± 15.43 mL/min) and nicardipine (48.01 ± 13.77 mL/min; P = .503). CONCLUSION: Topical treatment with Ca+ channel blockers reduces radial artery spasm and significantly increases the free flow through the radial artery conduit. Nicardipine is a safe and effective alternative of verapamil in preventing spasm of radial artery conduit.

Quality of life after coronary bypass: a multicentre study of routinely collected health data in the Netherlands†.

OBJECTIVES: In this study, our aim was to explore how coronary artery bypass grafting affects quality of life, and how this varies with age, particularly with patients at risk of deterioration. METHODS: In a retrospective, multicentre cohort study, patients with isolated coronary artery bypass grafting and electively operated between January 2011 and January 2015 with pre- and postoperative quality-of-life data were included. Patients were classified into 3 age groups: <65, 65-79 and ≥80 years. Quality of life was measured up to 1-year follow-up using the Short Form-12 or the Short Form-36 health survey. A multivariable, linear regression analysis, with an adjustment for confounders, was used to evaluate the association between age and quality of life. RESULTS: A total of 2606 patients were included in this study. Upon one-year of follow-up, the mean physical health of patients increased from 54 at baseline to 68, and mental health increased from 60 to 67. We observed decreased mental health in 20% of patients aged <65 years, 20% of patients aged 65-79 years and 29% of patients aged ≥80 years (P = 0.039). In this study, age was not associated with a lower physical or mental component score (P = 0.054 and P = 0.13, respectively). Independent risk factors for a decrease in quality of life consist of a better physical and mental score at baseline (P < 0.001) and a reduced left ventricular function (P < 0.001). CONCLUSIONS: Most patients experience a relevant increase in physical and mental quality of life, but a proportion of patients aged ≥80 years undergo significant deterioration in mental health.

The influence of oxygen delivery during cardiopulmonary bypass on the incidence of delirium in CABG patients; a retrospective study.

INTRODUCTION: Postoperative delirium is the most common neurological complication of cardiac surgery. Hypoxia has been shown to increase the risk of postoperative delirium. The possibility to continuously monitor oxygen delivery (DO2) during cardiopulmonary bypass (CPB) offers an adequate approximation of the oxygen status in a patient. This study investigates the role of oxygen delivery during cardiopulmonary bypass in the incidence of postoperative delirium. METHODS: Three hundred and fifty-seven adult patients who underwent normothermic coronary artery bypass grafting (CABG) surgery were included in this retrospective study. The nadir indexed DO2 (DO2i) value on bypass, the total time under the critical DO2i level and the area under the curve (AUC) for critical DO2i were determined. Delirium was identified by the postoperative administration of haloperidol. RESULTS: The mean nadir DO2i significantly differed, comparing the group of patients with postoperative delirium to the group without. Multivariate analysis only identified age, pre-existing cognitive impairment, preoperative kidney dysfunction and cross-clamp time as independent risk factors for delirium. The results also indicated that patients of older age were more sensitive to a declined DO2i. CONCLUSION: A low DO2i during cardiopulmonary bypass is significantly associated with the incidence of postoperative delirium in CABG patients. However, the role of DO2 as an independent predictor of delirium could not be proven.

Management of right ventricular injury after localization of the left anterior descending coronary artery.

During coronary artery bypass surgery an intramyocardial or intracavitary left anterior descending coronary artery can be difficult to locate and pose problems of inadvertent entry into the right ventricle. We present a literature review of the management of this injury. We report an additional aid to prevent injury to the left anterior descending coronary artery during closure of the right ventriculotomy.

Antithrombotic therapy after bioprosthetic aortic valve replacement: ACTION Registry survey results.

AIMS: A variety of antithrombotic regimens have been described for the early postoperative period after bioprosthetic aortic valve replacement (AVR). This study reviews antithrombotic practice for patients undergoing bioprosthetic AVR with or without coronary artery bypass graft (CABG) amongst the centers participating in the ACTION (Anticoagulation Treatment Influence on Postoperative Patients) Registry. METHODS AND RESULTS: An antithrombotic therapy questionnaire was answered by the 49 centers participating in the ACTION Registry located in Europe, Middle East, Canada and Asia. The 43% of centers prescribe vitamin K antagonist (VKA), 20% prescribe VKA and acetyl salicylic acid (ASA), 33% prescribe only ASA and 4% do not prescribe any therapy after bioprosthetic AVR. For patients undergoing bioprosthetic AVR and CABG 39% of the centers prescribe VKA and ASA, 37% prescribe VKA and 24% prescribe ASA. After the first three postoperative months following bioprosthetic AVR, 61% of the centers prescribe only ASA, while 39% do not prescribe any therapy. Patients with bioprosthetic AVR and CABG receive ASA in 90% centers, in 2% centers VKA and ASA, and 8% centers do not prescribe any antithrombotic. CONCLUSION: This study demonstrates that, despite guidelines published by several professional societies, medical practice for the prevention of thrombotic events early after bioprosthetic AVR varies widely among cardiac surgical centers.

Cardiac tamponade: an unusual, lifethreatening complication after transhiatal resection of the esophagus.

Transhiatal resection for carcinoma of the distal esophagus is associated with relative high morbidity and mortality. We present a rare case of cardiac tamponade after transhiatal esophagectomy for which emergency sternotomy was performed. Probably the retraction of the heart during exploration of the mediastinum caused a laceration of an epicardial vein. Although very rare, cardiac tamponade should be considered when hemodynamic instability during or after transhiatal esophagectomy occurs.

Influence of orientation of bi-leaflet valve prostheses on coronary perfusion pressure in humans.

Orientation of a bi-leaflet prosthesis (BLP) might influence coronary perfusion. The aim of this study was to investigate the influence of the orientation on coronary perfusion pressure during hyperemia and adrenergic stimulation. During hyperemia perfusion pressure determines coronary blood flow. Fourteen patients with normal coronary angiogram underwent aortic valve replacement (AVR) by a BLP, and seven received a bio-prosthesis. Patients receiving a BLP were randomized to either orientation A (hinge mechanism perpendicular to a line drawn between the coronary ostia) or B (hinge mechanism parallel to the line between the ostia). Six months after surgery all patients underwent cardiac catheterization. Pressures were measured during resting conditions, during maximum hyperemia, and during maximum adrenergic stimulation with a guiding catheter in the aortic arch (P(ao)), simultaneously with a sensor tipped guide wire in the coronary artery (P(cor)) and in the aortic root (P(root)). P(ao)-P(root) described a flow-induced pressure drop in the aortic root (Venturi effect) and the gradient P(root)-P(cor) described coronary ostium abnormalities. Only small non-significant differences in myocardial perfusion pressure were found between different orientations of a bi-leaflet prosthesis or between bi-leaflet prostheses and bio-prostheses in P(ao)-P(root) and P(root)-P(cor).