HeartMate II implantation technique that spares the sternum and ascending aorta

Left ventricular assist devices (LVADs) have become the standard therapy for patients with end-stage heart failure, and the use of LVADs for long-term support has grown exponentially over the past decade. As the number of LVAD implantations has increased, surgeons have faced more challenging cases, such as those in which the patient has previously undergone a sternotomy. The HeartMate II is one of the most widely implanted LVADs. The standard procedure for HeartMate II implantation is median sternotomy and sewing the outflow graft to the ascending aorta. However, in patients with sternal comorbidities, it can be advantageous to use a less invasive approach that avoids this procedure. We describe the case of a 64-year-old man with a history of end-stage ischemic cardiomyopathy who had previously undergone a median sternotomy and a coronary artery bypass grafting operation and had patent grafts. He required a HeartMate II LVAD (destination therapy), which was implanted via a left subcostal incision; the pump was placed subdiaphragmatically, and the outflow graft was sewed to the descending aorta to avoid a complicated redo cardiac operation via median sternotomy and to minimize the risk of injuring the patent bypass grafts. The patient survived for more than 500 days postoperatively. This approach is feasible and could be a safer method for implanting a HeartMate II device in patients with serious comorbidities that preclude the use of the traditional implantation techniques.     

Left ventricular assist device implantation after plasma exchange for heparin-induced thrombocytopenia

Treating a patient with heparin-induced thrombocytopenia can be challenging particularly when the patient requires urgent cardiac surgery that uses heparin for anticoagulation. We herein report a case of a 61-year-old man with idiopathic dilated cardiomyopathy associated with heparin-induced thrombocytopenia and who underwent plasma exchange to remove heparin-induced thrombocytopenia antibodies before undergoing left ventricular assist device implantation. The surgery was performed using cardiopulmonary bypass and unfractionated heparin.     

Development of an algorithm to automatically compress a CT image to visually lossless threshold

Background

To develop an algorithm to predict the visually lossless thresholds (VLTs) of CT images solely using the original images by exploiting the image features and DICOM header information for JPEG2000 compression and to evaluate the algorithm in comparison with pre-existing image fidelity metrics.

Methods

Five radiologists independently determined the VLT for 206 body CT images for JPEG2000 compression using QUEST procedure. The images were divided into training (n?=?103) and testing (n?=?103) sets. Using the training set, a multiple linear regression (MLR) model was constructed regarding the image features and DICOM header information as independent variables and regarding the VLTs determined with median value of the radiologists’ responses (VLT_rad) as dependent variable, after determining an optimal subset of independent variables by backward stepwise selection in a cross-validation scheme.The performance was evaluated on the testing set by measuring absolute differences and intra-class correlation (ICC) coefficient between the VLT_rad and the VLTs predicted by the model (VLT_model). The performance of the model was also compared two metrics, peak signal-to-noise ratio (PSNR) and high-dynamic range visual difference predictor (HDRVDP). The time for computing VLTs between MLR model, PSNR, and HDRVDP were compared using the repeated ANOVA with a post-hoc analysis. P?<?0.05 was considered to indicate a statistically significant difference.

Results

The means of absolute differences with the VLT_rad were 0.58 (95% CI, 0.48, 0.67), 0.73 (0.61, 0.85), and 0.68 (0.58, 0.79), for the MLR model, PSNR, and HDRVDP, respectively, showing significant difference between them (p?<?0.01). The ICC coefficients of MLR model, PSNR, and HDRVDP were 0.88 (95% CI, 0.81, 0.95), 0.85 (0.79, 0.91), and 0.84 (0.77, 0.91). The computing times for calculating VLT per image were 1.5?±?0.1 s, 3.9?±?0.3 s, and 68.2?±?1.4 s, for MLR metric, PSNR, and HDRVDP, respectively.

Conclusions

The proposed MLR model directly predicting the VLT of a given CT image showed competitive performance to those of image fidelity metrics with less computational expenses. The model would be promising to be used for adaptive compression of CT images.

     

Surgical relevance of the lateral costotransverse ligament in relation to the dorsal root ganglion

The lateral costotransverse ligament, a short band that stabilizes the costovertebral joint, is found in close proximity to the dorsal root ganglion. This ligament is an important surgical landmark during tumor resections or nerve blocks in the paravertebral space. The purpose of this study was to quantitatively and qualitatively describe the morphology of the lateral costotransverse ligament and its relation to the dorsal root ganglion at all levels of the thoracic spine. The thoracic spines of eight embalmed cadavers were dissected bilaterally. The length, width, and thickness of the ligament were measured. The distance from the inferolateral aspect of the ligament to the lateral aspect of the dorsal root ganglion was also measured. Three bilateral groups of lateral costotransverse ligaments, top (on ribs 1–2), middle (on ribs 3–10), and bottom (on ribs 11–12), were compared based on anatomic distinctions between the costotransverse joints, which can influence ligament morphology. Among the three groups, the differences between the length, width, and thickness were not statistically significant. However, the distance from the lateral costotransverse ligament to the dorsal root ganglion differed significantly (P = 0.000), with the middle group having the longest distance, and the bottom group having the shortest distance. This finding can help clinicians and surgeons avoid iatrogenic injuries of neural structures during thoracic spine surgery, or when performing nerve blocks in the paravertebral space.     

Dorsal metacarpal veins: anatomic variation and potential clinical implications

The dorsal metacarpal veins are frequently cannulated. Cannulation success is determined by several variable anatomic features. The objective of this study is to classify, for the first time, the anatomic variants of the dorsal metacarpal veins. In this cross-sectional study, 520 university students and staff were conveniently recruited. The dorsal metacarpal veins in 1040 hands were studied. Venous visibility was enhanced by either tourniquet application or near-infrared illumination. Variant patterns of the dorsal metacarpal veins were classified. The final analysis included 726 hands, for an exclusion rate of 30 %. Eight pattern types were identified. Three anatomic features informed the variation. Bilateral symmetry of the dorsal metacarpal veins was present in 352 participants (83 % of the total). The overall frequency distribution of variants in both hands was similar (P = 0.8). The frequency distribution of variants was subject to sexual dimorphism (P = 0.001), ethnic variation (P < 0.001), and technical variation (P < 0.001). The anatomic variants of the dorsal metacarpal veins were sorted into decreasingly frequent primary, secondary, and tertiary groups. The groups may signify a progressive increase in difficulty of peripheral cannulation, in the mentioned order. As such, primary patterns are the most common and likely the easiest to cannulate, while tertiary patterns are the least common and likely the most difficult to cannulate. The preceding premise, in tandem with the bilateral asymmetry of the veins, is clinically significant. With cannulation difficulty likely signifying an underlying tertiary pattern, the contralateral dorsal metacarpal veins are probabilistically characterized by a primary pattern and are, as such, the easier option for peripheral venous cannulation.     

Prevalence of cribra orbitalia in Pacopampa during the formative period in Peru

Cribra orbitalia is characterized by an aggregation of small apertures in the orbital roof in response to marrow hypertrophy. This pathological change is indicative of biological stress during youth. We examined the prevalence of this lesion in Pacopampa, a ceremonial center of the formative period, located in the northern highlands of Peru. Using this evaluation of cribra orbitalia, we reconstructed aspects of the population’s health and nutritional status during the formation of Andean civilization. We examined 41 orbits of 27 adult individuals (13 males, 14 females) and recorded the macroscopic presence or absence of cribra orbitalia. The presence or absence of cribra orbitalia was the same bilaterally for all 14 individuals having both orbits preserved. The pathology was present in two of the 13 males (15.4%), one of the 14 (7.1%) females, and three of 27 individuals (11.1%) for both sexes combined. There was no difference in the frequency between sexes. The prevalence of cribra orbitalia was found to be lower in Pacopampa than in the comparative data of coastal populations. It is reasonable to assume that the increase in social complexity in Pacopampa was probably unrelated to the decline in overall health of the people.     

Considering the inferior surface area of lower lumbar vertebrae: determining weight transmission pattern at the lumbosacral junction

The biomechanical function of the lumbosacral junction (LSJ) is obscure, but its medical significance is not, as it is the most common site of low back pain. In this study, we analyzed the difference between the mean values of the surface areas of the inferior body and total inferior facet areas of the fourth and fifth lumbar vertebrae. We aimed to define the function of the LSJ during weight transmission and clarify its mechanical significance. Vertebral columns of 45 adult male human cadavers from five anatomy departments in Nigeria were cut at the L3–L4 intervertebral disc and macerated. Using the graph paper method, the mean values of the surface area of the inferior body and total facet area of the fourth and fifth lumbar vertebrae were 1356 ± 26 and 329 ± 6 and 1277 ± 27 and 418 ± 8 mm², respectively. The relationships between the fourth and fifth lumbar vertebrae paired variables were highly significant (P < 0.001). A sudden reduction in the surface area of the inferior body of the fifth lumbar vertebra was compensated for by a corresponding increase in its total inferior facet area, which indicated that corresponding weight was diverted from the anterior column to the posterior column at the LSJ. This pattern of weight transmission may be a beneficial functional adaptation in man to protect the relatively large intervertebral disc of the LSJ in bipedal posture, or it may predispose the LSJ synovial zygapophyseal joints to mechanical stress.     

A simple pyramid-shaped microchamber towards highly efficient isolation of circulating tumor cells from breast cancer patients

Isolation and detection of circulating tumor cells (CTCs) has showed a great clinical impact for tumor diagnosis and treatment monitoring. Despite significant progresses of the existing technologies, feasible and cost-effective CTC isolation techniques are more desirable. In this study, a novel method was developed for highly efficient isolation of CTCs from breast cancer patients based on biophysical properties using a pyramid-shaped microchamber. Through optimization tests, the outlet height of 6 μm and the flow rate of 200 μL/min were chosen as the optimal conditions. The capture efficiencies of more than 85% were achieved for cancer cell lines (SKBR3, BGC823, PC3, and H1975) spiked in DMEM and healthy blood samples without clogging issue. In clinic assay, the platform identified CTCs in 13 of 20 breast cancer patients (65%) with an average of 4.25?±?4.96 CTCs/2 mL, whereas only one cell was recognized as CTC in 1 of 15 healthy blood samples. The statistical analyses results demonstrated that both CTC positive rate and CTC counts were positive correlated with TNM stage (p < 0.001; p?=?0.02, respectively). This microfluidic platform successfully demonstrated the clinical feasibility of CTC isolation and would hold great potential of clinical application in predicting and monitoring the prognosis of cancer patients.     

Compensatory force measurement and multimodal force feedback for remote-controlled vascular interventional robot

Minimally invasive vascular interventional surgery is widely used and remote-controlled vascular interventional surgery robots (RVIRs) are being developed to reduce the occupational risk of the intervening physician in minimally invasive vascular interventional surgeries. Skilled surgeon performs surgeries mainly depending on the detection of collisions. Inaccurate force feedback will be difficult for surgeons to perform surgeries or even results in medical accidents. In addition, the surgeon cannot quickly and easily distinguish whether the proximal force exceeds the safety threshold of blood vessels or not, and thus it results in damage to the blood vessels. In this paper, we present a novel method comprising compensatory force measurement and multimodal force feedback (MFF). Calibration experiments and performance evaluation experiments were carried out. Experimental results demonstrated that the proposed method can measure the proximal force of catheter/guidewire accurately and assist surgeons to distinguish the change of proximal force more easily. This novel method is suitable for use in actual surgical operations.