Penetration detection with intention recognition for cooperatively controlled robotic needle insertion

In lumbar puncture surgeries, force and position information throughout the insertion procedure is vital for needle tip localization, because it reflects different tissue properties. Especially in pediatric cases, the changes are always insignificant for surgeons to sense the crucial feeling of loss of resistance. In this study, a robot system is developed to tackle the major clinical difficulties. Four different control algorithms with intention recognition ability are applied on a novel lumbar puncture robot system for better human–robot cooperation. Specific penetration detection based on force and position derivatives captures the feeling of loss of resistance, which is deemed crucial for needle tip location. Kinematic and actuation modeling provides a clear description of the hardware setup. The control algorithm experiment compares the human–robot cooperation performance of proposed algorithms. The experiment also dictates the clear role of designed penetration detection criteria in capturing the penetration, improving the success rate, and ensuring operational safety.

THE HISTORY OF THE LIMIT STATE DESIGN METHOD

This paper analyzes the 70-year history of development of the limit state design method (LSDM) focusing on the fundamentals of the design codes based on this method and considers proposals for improving the LSDM and its justification. It was also noted that the reaction of the system in any of its fixed states is not always sufficient to assess the reliability of the system, and therefore it is necessary to analyze the rate of loss of resistance of load-bearing structures. However, probabilistic considerations were not enough due to the lack of reliable statistical data in the area of extreme sections of the distribution curves and a number of other circumstances (features of control procedures, different behavior of the material in the structure and in the samples, etc.). This paper analyzes some fundamental issues that should be solved when developing the method for the nonlinear analysis.

Comparison of contralateral oblique view with the lateral view for fluoroscopic-guided cervical epidural steroid injection: a randomized clinical trial

BackgroundCervical epidural steroid injection is associated with rare but potentially catastrophic complications. The contralateral oblique (CLO) view may be a safe and feasible alternative to the lateral (LAT) view for fluoroscopic-guided cervical epidural steroid injection. However, evidence for the clinical usefulness of the CLO view for cervical epidural steroid injection is lacking. We assessed the clinical usefulness of the CLO view for cervical epidural steroid injection in managing cervical herniated intervertebral discs.MethodsPatients were randomly assigned to receive fluoroscopic-guided cervical epidural steroid injection under LAT view or CLO view at 50±5° degrees groups. The primary outcome was the needling time comparison between the two groups. Secondary outcomes were comparison of first-attempt success rate, needle tip visualization and location, total number of needle passes, final success rate, crossover success rate and false-positive/negative loss of resistance. Complications and radiation dose were also compared.ResultsThe needling time significantly decreased in the CLO than in the LAT group. The first-attempt success rate was significantly higher in the CLO compared with the LAT group. The needle tip was clearly visualized (p<0.001) and located more often on (or just anterior to) the ventral interlaminar line (p<0.001) in the CLO than in the LAT group. There were significantly fewer needle passes (p=0.019) in the CLO than in the LAT group. There were no significant differences in the final success, crossover success, false-positive/negative loss of resistance or radiation dose between the groups. Two (5.9%) cases in the LAT group experienced complications.ConclusionThe CLO view may be recommended for fluoroscopic-guided cervical epidural steroid injection, considering its better clinical usefulness over the LAT view.

Anatomy of the lumbar interspinous ligament: findings relevant to epidural insertion using loss of resistance

Background and objectivesThe ‘loss of resistance’ technique is used to determine entry into the epidural space, often by a midline needle in the interspinous ligament before the ligamentum flavum. Anatomical explanations for loss of resistance without entry into the epidural space are lacking. This investigation aimed to improve morphometric characterization of the lumbar interspinous ligament by observation and measurement at dissection and from MRI.MethodsMeasurements were made on 14 embalmed donor lumbar spines (T12 to S1) imaged with MRI and then dissected along a tilted axial plane aligned with the lumbar interspace.ResultsIn 73 interspaces, median (IQR) lumbar interspinous plus supraspinous ligament length was 29.7 mm (25.5–33.4). Posterior width was 9.2 mm (7.7, 11.9), with narrowing in the middle (4.5 mm (3.0, 6.8)) and an anterior width of 7.3 mm (5.7, 9.8).Fat-filled gaps were present within 55 (75%). Of 51 anterior gaps, 49 (67%) were related to the ligamenta flava junction. Median (IQR) gap length and width were 3.5 mm (2.5, 5.1) and 1.1 mm (0.9, 1.7).Detection of gaps with MRI had 100% sensitivity (95% CI 93.5 to 100), 94.4% specificity (72.7, 99.9), 98.2% (90.4, 100) positive predictive value and 100% (80.5, 100) negative predictive value against dissection as the gold standard.ConclusionsThe lumbar interspinous ligament plus supraspinous ligament are biconcave axially. It commonly has fat-filled gaps, particularly anteriorly. These anatomical features may form the anatomical basis for false or equivocal loss of resistance.

Estimating the Rates of Acquisition and loss of Resistance of Enterobacteriaceae to Antimicrobial Drugs in Pre-Weaned Dairy Calves

The objective of this study was to investigate the effect of the antimicrobial drugs (AMD) on the shedding of resistant Enterobacteriaceae in feces of pre-weaned dairy calves. The AMD considered were ceftiofur, administered parenterally, and neomycin sulfate added in milk replacer and fed to calves during the first 20 days of life. Fifty-five calves, aged one to three days, were enrolled and followed to 64 days. Fecal samples were collected three times/week and treatments recorded daily. Enterobacteriaceae were quantified for a subset of 33 calves using spiral plating on plain, ceftiofur supplemented, and neomycin supplemented MacConkey agar. Negative binomial models were used to predict the association between treatment with AMD and the gain and loss of Enterobacteriaceae resistance over time. Acquisition of resistance by the Enterobacteriaceae occurred during treatment and peaked between days three to four post-treatment before decreasing to below treatment levels at days seven to eight post-treatment. Acquisition of neomycin resistance was observed on the first sampling day (day four from the start of feeding medicated milk replacer) to day eight, followed by cyclical peaks until day 29, when the Enterobacteriaceae counts decreased below pre-treatment. Enterobacteriaceae resistance against both AMD increased after AMD administration and didn’t return to pre-therapeutic status until seven or more days after therapy had been discontinued. The study findings provide valuable insights into the dynamics of Enterobacteriaceae under routine AMD use in calves.

Pocketbook on Regional Anesthesia Techniques: Each Line Matters

Dear editor, There has been an ardent interest noticed in the last decade amongst members of anaesthesia fraternity to learn the art of regional anaesthesia (RA). Use of ultrasound (US) has revolutionised the practice of RA all over the world. Every month there is a description of either a new block or a modification of an existing block. Although this keeps RA enthusiasts occupied with various experiments and thus reinventing his/her skills, it also adds to the confusion. The US workshops are useful to Anaesthesiologist’s who have access to the US. Practitioners in the periphery especially freelancers and Anaesthesiologists working in small, resource-limited setups are the ones who should be skillful in landmark/ loss of resistance (LOR) and peripheral nerve stimulation (PNS) guided RA techniques. Anatomy, landmarks, and techniques are equally important [1]. RA that is usually taught in medical colleges and teaching institutes to postgraduate students are spinal/epidural anaesthesia, few upper limb blocks (supraclavicular/axillary), and few lower limb blocks (femoral/sciatic/popliteal). The students do not get adequate confidence during training and later either have to attend workshops or become faculty in some teaching institutes to master RA skills. The relationship between nerve and needle tip at the moment of injection is critical. Nerve localisation techniques have evolved over the years [2]. There are workshops conducted all over the globe that teach US and PNS-guided RA techniques. However, it has been observed that the participants are mostly not actively practicing hands-on during such sessions. An illustrated pocketbook showing images, key points, and relevant landmarks of the regularly performed RA techniques were therefore long-awaited. Finally, three RA enthusiasts from India: Dr. Santosh Kumar Sharma, Dr. Tuhin Mistry, and Dr. Kala Eshwaran have compiled a book in which they have described LOR-based and PNS-guided techniques using illustrated and sel

The roles of history, chance, and natural selection in the evolution of antibiotic resistance

History, chance, and selection are the fundamental factors that drive and constrain evolution. We designed evolution experiments to disentangle and quantify effects of these forces on the evolution of antibiotic resistance. Previously we showed that selection of the pathogen Acinetobacter baumannii in both structured and unstructured environments containing the antibiotic ciprofloxacin produced distinct genotypes and phenotypes, with lower resistance in biofilms as well as collateral sensitivity to b-lactam drugs (Santos-Lopez et al. 2019). Here we study how this prior history influences subsequent evolution in new b-lactam antibiotics. Selection was imposed by increasing concentrations of ceftazidime and imipenem and chance differences arose as random mutations among replicate populations. The effects of history were reduced by increasingly strong selection in new drugs, but not erased, at times revealing important contingencies. A history of selection in structured environments constrained resistance to new drugs and led to frequent loss of resistance to the initial drug by genetic reversions and not compensatory mutations. This research demonstrates that despite strong selective pressures of antibiotics leading to genetic parallelism, history can etch potential vulnerabilities to orthogonal drugs.

The Tissue Plane

In recent times, terms such as ‘interfascial plane block’ and ‘fascial plane block’ have become common in describing regional anaesthesia blocks such as transversus abdominis plane (TAP), serratus anterior plane (SAP) and erector spinae plane (ESP). In fact, none of these names accurately describes the applied anatomy involved in each named technique, as the acronym is only one part of the anatomic jigsaw puzzle. The correct term is ‘tissue plane block’, which derives from surgical terminology. The tissue plane is not new to regional anaesthesia, as it has been the endpoint of ‘loss of resistance’ and ‘pop’ techniques for many decades. However, the game-changer is that now we can see the tissue plane courtesy of ultrasound. The purpose of this chapter is to review the history of the tissue plane in relation to its use in regional anaesthesia, and to see how ultrasound has further advanced the regional anaesthesiologist’s options in this regard. The chapter will also review how an understanding of tissue dynamics can further enhance our clinical results by manipulating the characteristics of the tissue plane.

Evolution of a costly immunity to cestode parasites is a pyrrhic victory

Parasites impose fitness costs on their hosts. Biologists therefore tend to assume that natural selection favors infection-resistant hosts. Yet, when the immune response itself is costly, theory suggests selection may instead favor loss of resistance. Immune costs are rarely documented in nature, and there are few examples of adaptive loss of resistance. Here, we show that when marine threespine stickleback colonized freshwater lakes they gained resistance to the freshwater-associated tapeworm, Schistocephalus solidus. Extensive peritoneal fibrosis and inflammation contribute to suppression of cestode growth and viability, but also impose a substantial cost of reduced fecundity. Combining genetic mapping and population genomics, we find that the immune differences between tolerant and resistant populations arise from opposing selection in both populations acting, respectively, to reduce and increase resistance consistent with divergent optimization.