Low-powered implantable devices activated by ultrasonic energy transfer for physiological monitoring in soft tissue via functionalized electrochemical electrodes.

Ultrasounds (US) are one of the most used imaging techniques in medicine for assessing the physiological and pathological state of soft tissue. Apart from therapeutic applications, most of the interaction of the acoustic beams with tissues occur passively and without substantial modification to the physiology of the latter. However, US can also be used to remotely power implantable devices with sensing capabilities. In this study, we propose small-form devices interfaced with functionalized electrochemical electrodes for the detection of pH and lactate levels, powered by ultrasounds and data transmission through a Frequency Shift Keying (FSK) modulation technique. A custom-made piezoelectric transducer is responsible for converting the acoustic waves into electrical voltage at the device with operational levels as low as 0.5 V (power consumption of 10 µW) obtained from implantation distances of 50 mm inside tissue. This conjugated with the high sensitivity of the developed electrochemical sensors allows to detect and transmit local parameter variations below 0.1 pH (4.2 mV) and 1 mM lactate (70 nA). Potential applications include real-time access to intrabody tissue monitoring post-operatively, with the view of assessing proper soft tissue healing or infection detection by bacteria, as well as tissue cancer screening in structures such as the human breast.

High temporal resolution delayed analysis of clinical microdialysate streams.

This paper presents the use of tubing to store clinical microdialysis samples for delayed analysis with high temporal resolution, offering an alternative to traditional discrete offline microdialysis sampling. Samples stored in this way were found to be stable for up to 72 days at -80 °C. Examples of how this methodology can be applied to glucose and lactate measurement in a wide range of in vivo monitoring experiments are presented. This paper presents a general model, which allows for an informed choice of tubing parameters for a given storage time and flow rate avoiding high back pressure, which would otherwise cause the microdialysis probe to leak, while maximising temporal resolution.

Return of functional mobility after an open tibial fracture: a sensor-based longitudinal cohort study using the Hamlyn Mobility Score.

In this study we quantified and characterised the return of functional mobility following open tibial fracture using the Hamlyn Mobility Score. A total of 20 patients who had undergone reconstruction following this fracture were reviewed at three-month intervals for one year. An ear-worn movement sensor was used to assess their mobility and gait. The Hamlyn Mobility Score and its constituent kinematic features were calculated longitudinally, allowing analysis of mobility during recovery and between patients with varying grades of fracture. The mean score improved throughout the study period. Patients with more severe fractures recovered at a slower rate; those with a grade I Gustilo-Anderson fracture completing most of their recovery within three months, those with a grade II fracture within six months and those with a grade III fracture within nine months. Analysis of gait showed that the quality of walking continued to improve up to 12 months post-operatively, whereas the capacity to walk, as measured by the six-minute walking test, plateaued after six months. Late complications occurred in two patients, in whom the trajectory of recovery deviated by > 0.5 standard deviations below that of the remaining patients. This is the first objective, longitudinal assessment of functional recovery in patients with an open tibial fracture, providing some clarification of the differences in prognosis and recovery associated with different grades of fracture.

RMP promotes venous metastases of hepatocellular carcinoma through promoting IL-6 transcription.

Hepatocellular carcinoma (HCC) is believed to arise from tumor-initiating cells (T-ICs), which are responsible for tumor relapse and metastases. Portal vein tumor thrombus (PVTT) is raised from HCC and strongly correlated to a poor prognosis. However, the mechanism underling the formation of PVTT is largely unknown. Herein, we provide evidence that RNA polymerase II subunit 5 (RPB5)-mediating protein (RMP) was progressively upregulated in PVTT and overexpressed RMP appeared to increase T-ICs self-renewal. Moreover, RMP promoted metastases of PVTT cells and HCC cells in vitro and in vivo. Knockdown of RMP attenuated T-ICs self-renewal and reversed epithelial-mesenchymal transition (EMT) in HCC and PVTT cells. The neutralizing assays suggested that interleukin-6 (IL-6) had an indispensable role in RMP regulating metastases and self-renewal of HCC cells. Furthermore, the transcription of IL-6 was verified to be modulated by RMP via interaction with p65 and RPB5, through which expanding the T-IC/cancer stem cell populations, as well as inducing EMT was promoted. These results suggested that RMP may promote PVTT formation by promoting IL-6 transcription. Thus, RMP serves as a potent factor contributed to develop PVTT and a promising therapeutic target for HCC patients.

Gait asymmetry detection in older adults using a light ear-worn sensor.

Measuring gait asymmetry is an important feature when characterizing functional imbalance between limbs. This could be due to pathologies, such as osteoarthritis, stroke, or associated with the effects of surgeries such as hip arthroplasty. Generally, the study of asymmetry or imbalance has required the use of a gait lab or force plates, which could be expensive and difficult to use in home settings. This work validates the use of a light weight ear sensor (7.4 g) with an instrumented treadmill for 64 subjects (age (60.04 (15.36)) including healthy subjects (14) as well as subjects who had been treated for hip (17), knee-replacement surgery (21) and knee osteoarthritis (12). Subjects performed treadmill walking at several speeds on flat surfaces, inclines and declines. Accelerometer data from the ear sensor were segmented into consecutive steps and temporal features were extracted. The measures of gait cycle time and step-period asymmetry obtained from the ear sensor matched well those of the treadmill for flat surfaces, inclines and declines. The key implication of the study is that the proposed method could replace expensive equipment for monitoring temporal gait features in clinics as well as free-living environments, which is important for monitoring rehabilitation after surgery and the progress of diseases affecting limb imbalance.

Robotic-assisted total mesorectal excision: should it be considered as the technique of choice in the management of rectal cancer?

The feasibility of robotic surgery has been extensively explored over the past decade with a more recent shift towards defining focused clinical applications for which quantifiable patient benefits can be directly attributed to its use. The aim of this article is to review the current literature on the use of daVinci robotic surgery for the management of rectal cancer and identify the potential benefits, if any, that robotic-assisted total mesorectal excision (RTME) may provide over the current conventional approach. A comprehensive search strategy was used to identify relevant evidence in order to explore the oncological, operative and functional outcome measures for the RTME in addition to quantifying the level of evidence which describes the clinical effectiveness of the daVinci robot in oncological surgery. Both robotic assisted techniques and the primary outcomes are discussed. In total, 23 studies were reviewed across 11 institutions, including one pilot randomised control trial. When data repetition is disregarded, a total of 452 robotic assisted laparoscopic anterior resections and 60 robotic-assisted laparoscopic abdomino-perineal excision of the rectum have been published since the introduction of the daVinci into clinical practice. Feasibility of the daVinci robotic assisted total mesorectal excision is demonstrated, with comparable oncological outcomes presented for rectal cancer excision. A demonstration of a reduced open conversion rate as well as of reduced hospital stay with the use of the robot is highlighted, although further trials are required to confirm both these findings. No functional benefit in using the daVinci could be confirmed due to the lack of focused trials in this area.

Validating two systems for estimating force and power.

This study examined the validity of 2 kinematic systems for estimating force and power during squat jumps. 12 weight-trained males each performed single repetition squat jumps with a 20-kg, 40-kg, 60-kg and 80-kg load on a Kistler portable force plate. A commercial linear position transducer (Gymaware [GYM]) and accelerometer (Myotest® [MYO]) were attached to the bar to assess concentric peak force (PF) and peak power (PP). Across all loads tested, the GYM and MYO estimates of PF and PP were moderately to strongly correlated ( P≤0.05-0.001) with the force plate measurements ( R=0.59-0.87 and R=0.66-0.97), respectively. The mean PF and PP values were not significantly different between the 2 kinematic systems and the force plate, but the estimates did produce some systematic bias and relatively large random errors, especially with the 20-kg load (PF bias >170 N, PF error >335 N, PP bias >400 W, PP error >878 W). Some proportional bias was also identified. In summary, the estimation of PF and PP by a linear position transducer and accelerometer showed moderate to strong relative validity and equivalent absolute validity, but these estimates are limited by the presence of bias and large random errors.

The role of robotic assisted laparoscopy for oesophagogastric oncological resection; an appraisal of the literature.

The introduction of surgical robotics to the field of surgical oncology brings with it an expectation not only of improved vision, instrumentation, and precision but also as a result, a potential for improved oncological outcomes. The current interest in the field of oesophagogastric oncology is explored in this review together with the benefits, real and potential, that robotic assistance offers surgical cancer resection as well as some of the limiting factors which may be hampering its uptake into current surgical practice. A systematic review of all the published literature up until April 2010 was examined across the field of esophageal and gastric cancer resection. A quantitative assessment of the oncological, operative, and functional outcomes was determined from each procedure. The level of evidence behind the results was determined using the Oxford Centre for Evidence-based Medicine Levels of Evidence; Therapy and Prevention. Three hundred and five cases from 19 independent studies were included for review. Nine studies explored the outcomes from robotic-assisted esophagectomy and eight, the robotic-assisted gastrectomy. Two articles included small case series of both procedures. The level of evidence was predominantly based on case series or expert opinion (Level 4 or 5) with only three unmatched or poorly matched comparative trials (Level 4) with no randomized trials evident. Improved operative outcomes and hospital stays were demonstrated with a reduction of 2 days when the robotic-assisted gastrectomy technique was employed compared with the open. No improvement in oncological outcomes could be identified with the use of the robot for either oesophageal or gastric cancer resection; however, in terms of short-term oncological outcomes, these were at least equivalent to the open approach for oesophageal cancer and early stage gastric cancer. Robotic-assisted laparoscopic surgery is a feasible technique to use to perform a safe and oncologically sound resection for oesophageal and early gastric cancer. Operative benefits appear to be encouragingly similar to the laparoscopic approach with some demonstration of improvement over the open technique despite a prolonged operative time. However, the level of evidence is suboptimal and more randomized controlled trials and long-term survival studies within a framework of measured and comparable outcomes is required.

The effect of dynamic vessel motion on haemodynamic parameters in the right coronary artery: a combined MR and CFD study.

Human right coronary artery (RCA) haemodynamics is investigated using computational fluid dynamics (CFD) based on subject-specific information from magnetic resonance (MR) acquisitions. The dynamically varying vascular geometry is reconstructed from MR images, incorporated in CFD in conjunction with pulsatile flow conditions obtained from MR velocity mapping performed on the same subject. The effects of dynamic vessel motion on instantaneous and cycle-averaged haemodynamic parameters, such as wall shear stress (WSS), time-averaged WSS (TAWSS) and oscillatory shear index (OSI), are examined by comparing an RCA model with a time-varying geometry and those with a static geometry, corresponding to nine different time-points in the cardiac cycle. The results show that the TAWSS is similar for the dynamic and static wall models, both qualitatively and quantitatively (correlation coefficient 0.89-0.95). Conversely, the OSI shows much poorer correlations (correlation coefficient 0.38-0.60), with the best correspondence being observed with the static models constructed from images acquired in late diastole (at t = 0 and 800 ms, the cardiac cycle is 900 ms). These findings suggest that neglecting dynamic motion of the RCA is acceptable if TAWSS is the primary focus but may result in underestimation of haemodynamic parameters related to the oscillatory nature of the blood flow.

Visual search behaviour in skeletal radiographs: a cross-specialty study.

AIM: To determine whether experience improves the consistency of visual search behaviour in fracture identification in plain radiographs, and the effect of specialization. MATERIAL AND METHODS: Twenty-five observers consisting of consultant radiologists, consultant orthopaedic surgeons, orthopaedic specialist registrars, orthopaedic senior house officers, and accident and emergency senior house officers examined 33 skeletal radiographs (shoulder, hand, and knee). Eye movement data were collected using a Tobii 1750 eye tracker with levels of diagnostic confidence collected simultaneously. Kullback-Leibler (KL) divergence and Gaussian mixture model fitting of fixation distance-to-fracture were used to calculate the consistency and the relationship between discovery and reflective visual search phases among different observer groups. RESULTS: Total time spent studying the radiograph was not significantly different between the groups. However, the expert groups had a higher number of true positives (p<0.001) with less dwell time on the fracture site (p<0.001) and smaller KL distance (r=0.062, p<0.001) between trials. The Gaussian mixture model revealed smaller mean squared error in the expert groups in hand radiographs (r=0.162, p=0.07); however, the reverse was true in shoulder radiographs (r=-0.287, p<0.001). The relative duration of the reflective phase decreases as the confidence level increased (r=0.266, p=0.074). CONCLUSIONS: Expert search behaviour exhibited higher accuracy and consistency whilst using less time fixating on fracture sites. This strategy conforms to the discovery and reflective phases of the global-focal model, where the reflective search may be implicated in the cross-referencing and conspicuity of the target, as well as the level of decision-making process involved. The effect of specialization appears to change the search strategy more than the effect of the length of training.