Marked Sites Research Articles

Automated detection and classification of acute vertebral body fractures using a convolutional neural network on computed tomography.

Acute vertebral fracture is usually caused by low-energy injury with osteoporosis and high-energy trauma. The AOSpine thoracolumbar spine injury classification system (AO classification) plays an important role in the diagnosis and treatment of the disease. The diagnosis and description of vertebral fractures according to the classification scheme requires a great deal of time and energy for radiologists. To design and validate a multistage deep learning system (multistage AO system) for the automatic detection, localization and classification of acute thoracolumbar vertebral body fractures according to AO classification on computed tomography. The CT images of 1,217 patients who came to our hospital from January 2015 to December 2019 were collected retrospectively. The fractures were marked and classified by 2 junior radiology residents according to the type A standard in the AO classification. Marked fracture sites included the upper endplate, lower endplate and posterior wall. When there were inconsistent opinions on classification labels, the final result was determined by a director radiologist. We integrated different networks into different stages of the overall framework. U-net and a graph convolutional neural network (U-GCN) are used to realize the location and classification of the thoracolumbar spine. Next, a classification network is used to detect whether the thoracolumbar spine has a fracture. In the third stage, we detect fractures in different parts of the thoracolumbar spine by using a multibranch output network and finally obtain the AO types. The mean age of the patients was 61.87 years with a standard deviation of 17.04 years, consisting of 760 female patients and 457 male patients. On vertebrae level, sensitivity for fracture detection was 95.23% in test dataset, with an accuracy of 97.93% and a specificity of 98.35%. For the classification of vertebral body fractures, the balanced accuracy was 79.56%, with an AUC of 0.904 for type A1, 0.945 for type A2, 0.878 for type A3 and 0.942 for type A4. The multistage AO system can automatically detect and classify acute vertebral body fractures in the thoracolumbar spine on CT images according to AO classification with high accuracy.

A note on East Australia Group V Stock humpback whale movement between feeding and breeding areas based on photo-identification

Documentation of humpback whale migratory movements between Australasia and the Southern Ocean has been limited almost exclusively to historical whaling data. This study examines photographic evidence documenting the movements of three individual humpback whales between their breeding grounds on the northeast coast of Australia and feeding grounds in Area V of the Southern Ocean. Although these individuals exhibited marked site fidelity to the same low latitude breeding grounds, their sightings in high latitude feeding grounds vary by 35° longitude, confirming dispersal of Eastern Australia Group V Stock humpback whales in the Antarctic feeding ground.

The Accuracy of Pre-Operative Ultrasonography in Localizing Parathyroid Adenoma for Minimally Invasive Parathyroidectomy (MIP)

OBJECTIVES To determine the sensitivity of pre-op ultrasonography in localizing parathyroid adenoma for minimally invasive parathyroidectomy (MIP) technique. METHODOLOGY The study was conducted at the department of ENT and Head & Neck Surgery, MTI Hayatabad Medical Complex Peshawar. It included a retrospective analysis of records of patients who underwent MIP from Jan 1, 2019, to July 31, 2022. All patients had pre-operative meta-iodobenzylguanidine (MIBG) scans, and serum PTH, Serum calcium levels were determined. A pre-op ultrasound scan was acquired to mark the site of the parathyroid adenoma. MIP was carried out using a 3.5 to 4 cm transverse skin incision over the marked site to expose the thyroid gland. If the marked parathyroid gland was identified without using any other aids, the result was labelled as "True positive". The sensitivity of pre-op ultrasonography was calculated using SPSS v 26.0. RESULTS A total of 53 cases were included in the study. The male: female ratio was 1:1.8. The ages of patients ranged from 23-70 years with a mean age of 48.49 years with a standard deviation of +_ 10.818. Pre-op ultrasonography accurately localizes the site of parathyroid adenoma in 49 patients. Statistical analysis showed this to be a significant finding. CONCLUSION Pre-op ultrasonography is significantly helpful in localizing the parathyroid adenoma. Therefore its routine use is recommended to help localize the adenoma in minimally invasive parathyroidectomy.

Epitope tag-specific differences in the detection of COSA-1 marked crossover sites in C. elegans spermatocytes.

Nascent crossover sites in C. elegans meiocytes can be cytologically detected using epitope-tagged versions of the pro-crossover protein COSA-1. In spermatocytes, differences exist between cytologically-detected and genetically-detected double crossover rates. Here, we examine nascent crossovers using both GFP- and OLLAS-tagged COSA-1. Similar to previous work, we find that most late pachytene spermatocytes display 5 COSA-1 foci, indicating one crossover per autosome bivalent. However, we detected more nuclei with >5 COSA-1 foci using OLLAS::COSA-1, reflecting some bivalents having 2 COSA-1 foci. These results demonstrate tag-specific differences in the detection of COSA-1 marked nascent crossovers in spermatocytes.

Manual Palpation versus Ultrasound to Identify the Intervertebral Space for Spinal Anesthesia in Infants.

Awake spinal anesthesia continues as an alternative to general anesthesia for infants. Standard clinical practice includes the manual palpation of surface landmarks to identify the desired intervertebral space for lumbar puncture (LP). The current study investigates the accuracy of manual palpation for identifying the intended intervertebral site for LP, using ultrasonography for confirmation and to determine the interspace where the conus medullaris ends. After informed parental consent, patients less than one year of age undergoing spinal anesthesia for lower abdominal, urologic, or lower extremity surgical procedures were included. Patients were held in the seated position and an attending pediatric anesthesiologist or pediatric anesthesiology fellow declared the vertebral interspace intended for needle insertion, palpated surface landmarks, and placed a mark at the site. A research anesthesiologist then determined the actual vertebral interspace of the marked site and the location of the conus medullaris using ultrasonography. The time to complete both techniques (manual palpation and ultrasonography) was recorded. The study cohort included 50 infants (median age of 7 months). Sixteen vertebral interspaces (32%) were inaccurately marked. One was marked two spaces higher than intended, ten were marked one space higher than intended, and five were marked one space lower than intended. In one patient, the intended vertebral interspace for the lumbar puncture overlaid the conus medullaris. The median time required was 25 seconds (IQR 14.3, 32) for palpation and 39 seconds (IQR 29, 63.8) for ultrasonography. Manual palpation of surface landmarks to determine the correct interspace for LP for spinal anesthesia in infants is inaccurate. The time required to perform spinal ultrasonography in infants for determination of the optimal site for LP is brief and may be useful in ensuring accurate identification of the correct interspace and the location of the conus medullaris.

How do seasonal changes in adult wolf defecation patterns affect scat detection probabilities?

Wolves are currently recolonising their historic range in France. The collection of scats is a widely used a non-invasive survey method to monitor wolf population size. However, seasonal changes in wolf faecal deposition patterns might affect the results of surveys. We used a detection dog and camera trapping (CT) to compare wolf scat detectability during winter and the nursing season. We collected 113 scats deposited by adult wolves at 29 marking sites on forest roads in the Sainte-Baume Regional Park, Provence, France. After parturition, the mean number of adult wolf scats increased by 160% inside the nursing territory and decreased by 80% outside of it. Around the time the pups are born, changes in faecal deposition patterns of adults make it easier to find scats around the wolf den (87% probability per wolf marking site) and harder to find scats outside the nursing territory (11% probability). During winter, the chance to find scats is equal (38 to 40% probability per wolf marking site) inside vs. outside the nursing territory. The combined use of a detection dog and camera traps allowed us to gather data on wolf defecation patterns non-invasively. Detectability of adult wolf scats during the nursing season is highly variable compared to winter due to seasonal behavioural changes affecting scat location. We conclude that surveys to collect samples and estimate wolf population size should be conducted exclusively during winter to avoid sampling biases.

OGBN V07 Laparoscopic repair of rare case of interparietal port-site incisional hernia with mesh in sub-lay; pre-peritoneal space

Abstract Background Interparietal hernias are defined as protrusions of intraabdominal contents within the layers of the abdominal wall. Primary interparietal hernias; like Spigelian's hernia are rare, 0.12% to 2% of all abdominal wall hernias. Recently, interparietal hernias are more encountered as incisional hernias. However, very few cases have been reported in literature of interparietal hernia at port site following laparoscopic surgery, keeping in mind that port site hernias incidence varies between 0.74% to 1.47% after laparoscopic surgical procedures. Here we are presenting a rare case of interparietal port site incisional hernia, its management and summarising the key steps for laparoscopic mesh in sub-lay (pre-peritoneal) plane with defect closure. Methods We present a case of 72-year-old gentleman, who had robotic prostatectomy in January 2020. He presented towards the end of that year with left lower abdominal ache and discomfort. On examination he had bout 2 cm palpable hernia in LLQ at the site of 11 mm port. CT scan confirms the hernia at port site where internal muscles had been damaged, but external oblique muscle remains intact. Hernia MDT discussion advised conservative management, given low probability of incarceration given the current hernia anatomy, and advised surgical intervention if hernia affecting daily activity and lifestyle. Clinical review after one year, patient describes more discomfort as dull pain that increases with his usual activity like gardening, walking or running, necessitating increasing analgesia for 2,3. The patient believes that this hernia is affecting his life. Repeat scan showed muscular defect within the left iliac fossa, between the left rectus abdominis medially and retracted transversus abdominis and internal oblique muscles laterally. The external oblique muscle and facia along with anterior rectus sheath are intact. After further discussion with patient regarding risks vs benefits, patient opted for surgical treatment with laparoscopic approach Results Patient in supine position. Pneumoperitoneum created using Veress needle at Palmer's point, 11mm optical-port in the right lumbar area. Laparoscopy confirmed bulging at the pre marked site of the hernia, another 2×5 mm ports. Bulging identified at hernia site. Anterior parietal peritoneum incised vertically along the midline and dissection carried out laterally to develop the pre-peritoneal space. Defect exposed and assessed. There was a horizontal rupture of the arcuate ligament across the posterior rectus sheath exposing a section of inferior epigastric vessels and rectus muscle. This rupture extends laterally to involve the transverse abdominus and internal obliques muscle total size defect of 6×3 cm. Defect closed with 1.0-Ehtilon that was introduced using Endo Close leaving the free end outside. The defect was closed continuously in two layers then the end was extracted and tied to free end trans-fascially under low abdominal pressure at the end of procedure. 20.3×15.2 Ventralight ST Mesh placed in the pre peritoneal plane after marking the centre with one 2.0-Prolene stitch that was used to anchor the mesh. Mesh was only fixed medially using AbsorbaTack to avoid post operative pain. Then the peritoneum was closed in the midline, covering the mesh using AbsorbaTack. Conclusions Interparietal hernias usually present with discomfort, pain or acutely due to incarceration or strangulation. Very little is reported regarding the presentation of interparietal port site hernia as few are reported in literature. This abstract describes a rare interparietal port site incisional hernia that is presented with pain and discomfort, affecting lifestyle. Furthermore, we describe an approach to repair the hernia without disturbing the intact anterior fascia, utilizing a combination of defect closure and synthetic prothesis placed in the pre peritoneal space, thus minimising the chance of future mesh complication. This case highlights not only the importance of closing port site more than 11 mm but more importantly the need to make sure that all abdominal wall layers are included to avoid interparietal hernia at port site.

The interpolation between random walk and self-avoiding walk by avoiding marked sites

The self-avoiding walk (SAW) on a regular lattice is one of the most important and classic problems in statistical mechanics with major applications in polymer chemistry. Random walk is an exactly solved problem while SAW is an open problem so far. We interpolate these two limits in 1D and 2D by considering a model in which the walker marks certain sites in time and does not visit them again. We study two variants: (a) the walker marks sites at every k time-steps, in this case, it is possible to enumerate all possible paths of a given length. (b) The walker marks sites with a certain probability p. For k = 1 or p = 1, the walk reduces to the usual SAW. We compute the average trapping time and distance covered by a walker as a function of the number of steps and radius of gyration in these cases. We observe that 1D deterministic, 1D probabilistic, and 2D deterministic cases are in the same universality class as SAW while 2D probabilistic case shows continuously varying exponents.

Manipulation of ferroelectric domain inversion and growth by optically induced 3D thermoelectric field in lithium niobate

We experimentally demonstrate the use of a femtosecond laser-induced thermoelectric field to manipulate remotely—not only at the focal spot—the inversion and growth of ferroelectric domain in lithium niobate. The process involves two steps: the first step is laser marking, in which a laser is used to mark the origin of the desired domain inversion. The second step is laser induction, in which a laser-induced thermoelectric field is used to invert the domain at the marker site and drive domain growth. The induced thermoelectric field is distributed in three dimensions, which can simultaneously manipulate the domain inversion and growth length of multiple marked sites within a diameter of ∼200 μm. The length of domain growth is synergistically controlled by the position and intensity of marking and induction, which can exceed 100 μm. This two-step poling method greatly improves the efficiency of all-optical poling and provides a different suite of tools for tailoring ferroelectric domains.

G-quadruplexes Mark Sites of Methylation Instability Associated with Ageing and Cancer.

Regulation of the epigenome is critical for healthy cell function but can become disrupted with age, leading to aberrant epigenetic profiles including altered DNA methylation. Recent studies have indicated that DNA methylation homeostasis can be compromised by the formation of DNA secondary structures known as G-quadruplexes (G4s), which form in guanine-rich regions of the genome. G4s can be recognised and bound by certain methylation-regulating enzymes, and in turn perturb the surrounding methylation architecture. However, the effect G4 formation has on DNA methylation at critical epigenetic sites remains elusive and poorly explored. In this work, we investigate the association between G4 sequences and prominent DNA methylation sites, termed ‘ageing clocks’, that act as bona fide dysregulated regions in aged and cancerous cells. Using a combination of in vitro (G4-seq) and in cellulo (BG4-ChIP) G4 distribution maps, we show that ageing clocks sites are significantly enriched with G4-forming sequences. The observed enrichment also varies across species and cell lines, being least significant in healthy cells and more pronounced in tumorigenic cells. Overall, our results suggest a biological significance of G4s in the realm of DNA methylation, which may be important for further deciphering the driving forces of diseases characterised by epigenetic abnormality, including ageing.

Hitting times of quantum and classical random walks in potential spaces

The spatial search problem is an interesting and important problem in computer science and especially the area of algorithms. The objective is a marked site to be found in a finite physical space, that can be modeled as a finite lattice or a graph. Many approaches have been developed to address this problem. Classical random walks and quantum walks are efficient models that address the spatial search problem. Quantum walks is a universal model of quantum computation and can be mapped directly to quantum circuits and consequently executed on quantum computers. Quantum walks utilized for quantum search proved to achieve significantly lower hitting times than their classical counterpart, classical random walks. The evolution space for the quantum walks as well as the classical random walks is up until now a free space. In our approach, we introduce external electrical potentials to the evolution space. We study the evolution of discrete time quantum and classical random walks in such potential spaces and the probability — hitting time on finding marked sites. We considered the differences in applied potential among neighboring sites as weights for the lattice — graph. We introduce these weights to the evolution space as an operator for the discrete time quantum walk and as coin probabilities for the classical random walk. Our results show that quantum walks again, evolve faster in the evolution space with the applied potential. Quantum walks also achieve better probability — hitting time on finding the marked site in the potential space. With the introduction of electrical potentials, quantum walks evolving in potential spaces, can lead to the development of novel quantum algorithms, where input parameters can be introduced as external potentials.

Interpack communication in African wild dogs at long-term shared marking sites

Scent marks deposited as semiochemical signals are a primary mode of communication for a broad range of mammal species. Such scent signals are often deposited at specific, frequently visited marking sites called latrines. Despite descriptions of widespread latrine use by numerous mammal species, detailed understanding of site visit rates and latrine function is lacking. Here we report for the first time a quantitative assessment of scent-marking behaviours that represent interpack olfactory communication by African wild dogs, Lycaon pictus, at latrines visited by multiple resident neighbouring packs, hereafter called a ‘shared marking site’ (SMS). We show that multiple packs visited specific SMSs frequently and regularly throughout the year, with a notable decrease in visits during the 3-month denning season coinciding with a contraction in range size. In addition to resident neighbouring packs, dispersing individuals visited and scent-marked at SMSs, suggesting that latrines function at least in part as sites communicating information about residence and possibly reproductive status. Further detailed investigation of the relevance of latrine use to territorial behaviour, ranging, habitat use and dispersal in this species is required, particularly as it may have direct applied conservation implications for this wide-ranging but territorial endangered species.

Cheetah marking sites are also used by other species for communication: evidence from photographic data in a comparative setup

Many mammalian species communicate via olfactory communication placed at particular locations. The majority of these studies focused on intraspecific communication. More recently, studies have also investigated interspecific communication and recorded prey animals sniffing olfactory cues left by predators and predators investigating or counter-marking cues left by other predator species. The purpose of exchanging olfactory cues within a species community is little understood. Using a comparative study design, we investigated the behaviour of a mammalian community at cheetah marking trees and paired control trees using camera traps on Namibian farmland. We tested the predictions derived from hypotheses regarding the reasons for visits to the marking trees. Cheetah marking trees and control trees were visited 1101 times by 29 mammalian species (excluding cheetahs), with more species recorded at the marking trees than control trees. Two competitively subordinate carnivore species made more visiting and sniffing events, respectively, at cheetah marking trees than control trees, possibly to assess the time since cheetahs were in the area. Two opportunistic scavenger species sniffed more frequently at the marking trees than control trees, perhaps to feed on undigested prey remains in scats. One common prey species of cheetahs had fewer visiting events at the marking trees than control trees, likely to reduce encounters with cheetahs. Further, one species that is rarely preyed by cheetahs marked cheetah marking trees at the same frequency as control trees, suggesting it uses conspicuous sites rather for intraspecific than interspecific communication. Thus, trees used by cheetahs for marking also play an important role in olfactory communication for a variety of mammalian species.

Was the decline of saltmarsh tabanid populations after the 2010 oil spill associated with change in the larval food web?

AbstractHorse flies of the species Tabanus nigrovittatus and Tabanus acutus are native to coastal marshlands. Their larvae are apex invertebrate predators, and their development is dependent on the food web in the marsh sediment. Surveillance of T. nigrovittatus after the 2010 Deepwater Horizon Oil Spill in the Gulf of Mexico showed population crashes of adult flies in southeast Louisiana marshes near oil landfall, but not in southwest Louisiana where oil did not reach. Sediment collection in 2011 from Louisiana marshes showed a near‐complete absence of larvae in the southeast yet high numbers in the southwest. We hypothesized that oil contamination destroyed critical components of the larval food web and/or residual toxicity led to larval death. We used 18S rRNA gene metagenomics to identify components of the food web in larval guts and sediment from southeast and southwest Louisiana marshes. Sediment oil contamination, biochemistry, and toxicity could not explain the lack of larvae in the southeast, because oiling at our high‐tide mark sites was low at the time of the study and toxicity was independent of sediment biochemistry. Hexapods were the main food web components in tabanid larval guts. Abundance of stink bug, vinegar fly, and mosquito species in the sediment was positively associated with the presence of larvae. However, these taxa were enriched in southeastern (near oil) versus southwestern (unoiled reference) sediment, and thus, lack of major food web components due to oiling could not explain lack of larva in the east. We conclude that the immediate crash in adult populations in oiled regions was the main cause for the absence of larvae the following year. While most saltmarsh arthropod groups had rebounded within a year after the oil spill, recovery of saltmarsh horse flies was ongoing for 5 years.

Under the bridge: marking sites prove the presence of Eurasian otter Lutra lutra in the Poljanska Sora River valley, Slovenia

Knowledge on distribution of the Eurasian otter (Lutra lutra) in Slovenia in the past was very limited, due to the lack of studies of this species. Hunting and persecution reduced the species distribution area and densities. After its legal protection in 1973, the species seems to have increased in population size. A few studies had shown the Eurasian otter repopulating the Alpine region. To confirm the presence of the species in the Slovenian Pre-Alps, we searched for otter scat – spraint, on six tributaries to the Poljanska Sora River of Polhograjsko hribovje, the Pre-Alpine mountains around Polhov Gradec. Otter marking sites were exclusively in the riverbed (100 %), with a great majority found under the bridges (83 %). Using camera traps, we were able to collect video evidence of the otter reproduction and confirm that the species is reproducing in the studied region. Since this area could act as a corridor for the otter’s recovery in the Adriatic River basin, it is crucial to continue to monitor its presence and the potential expansion to the west of the country.

STUDIES ON ARBUSCULAR MYCORRHIZAL FUNGI FROM SOIL OF SITAKHANDI FOREST OF MAHARASHTRA

Forest ecosystems are the regions where there is least human interference and therefore we see luxury of plant growth. Sithkhandi forest is one of the least human interfered forests present near Bhokar region of Nanded district in Maharashtra. Arbuscular mycorrhizal fungi (AM fungi) develops symbiotic relation with most of the land plants. This association is very common in the terrestrial ecosystem throughout the world. The objective of the current study is to identify and determine frequency of various AM fungal species. Five GPS marked sampling sites were selected for isolation of mycorrhizal spores. A total 34 species belonging to genera Glomus, Acaulospora, Scutellospora, Gigaspora, Diversispora, Enterophora and Pascispora were reported. Little variation is seen in their frequency. In this study, more species diversity among Glomus followed by Acaulospora were found. High frequency percentage of Glomus mosseae has been reported at all study sites.

Eco-crossover, or environmentally regulated crossing-over, and natural selection are two irreplaceable drivers of adaptive evolution: Eco-crossover hypothesis

The existence of an environmentally regulated version of meiotic crossing-over, or eco-crossover, is proposed, and the main consequences of this hypothesis are considered. Eco-crossover is a key source of partially directed genetic diversity of eukaryotes. In stressful environment, it creates ecologically justified and topologically specific genetic changes, and hence phenotypic variability, with which the selection works. If variability were random, then, in the face of rapid environmental changes, natural selection could not create life-saving adaptations in a timely manner. Owing to the eco-crossover activity, epimutations, i.e., eco-dependently marked chromosomal sites, are transforming into mutations. In its work, eco-crossover uses the eco-stress-dependent versions of circular RNAs (“ecological” circRNAs), which, against the background of eco-stresses, are synthesized as variants of alternative splicing. These ecological circRNAs, binding to homologous epimutations on the homologous parent chromosomes of the meiocyte, involve them in topologically specific recombinations. These recombinations can create random mutations in nonrandom genomic sites. These quasi-random mutations serve as a pivotal source for creating all adaptations of any level of complexity. The drivers of the adaptive evolution of eukaryotes, both in micro- and macroevolution, are two irreplaceable factors – eco-crossover and natural selection.

Novel non-invasive 12-lead ECG-based imaging method with potential to guide and optimise right ventricular lead implantation

Abstract Funding Acknowledgements Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Svend Andersens Foundation Karl G Andersens Foundation Helsefonden Background Right ventricular (RV) pacing may induce electrical and mechanical dyssynchrony which may lead to heart failure. Often, the physician aims for lead implantation at the RV septum as this is expected to result in a more physiologic activation compared to alternative RV lead locations. Fluoroscopy, often in combination with QRS morphology derived from the 12-lead ECG, is used to guide lead implantation. However, this method is inaccurate and can result in a non-optimal RV lead location. We present a novel non-invasive method to create patient-specific 3D electrical activation maps from the 12-lead ECG that has potential to support RV lead implantation. Methods Data from 34 patients with an implanted dual chamber pacemaker were used. A contrast-enhanced cardiac CT scan showing the RV lead implantation site was obtained as well as recording of a 12-lead ECG during RV pacing together with a 3D photo documenting the ECG electrode positions. Discrete patient-specific torso and heart models were created from the CT scans. Each torso model was merged with the 3D photo for precise placement of the ECG electrodes in relation to the heart (figure 1). Combining the 12-lead ECGs and the heart/torso models, patient-specific 3D electrical activation maps originating from the RV were created using a novel inverse-ECG technique applying electrophysiological rules. The accuracy of the inverse-ECG method was determined by comparing the earliest site of activation from the 3D activation map with the known RV insertion site marked on the CT scan. Results Documented by the implanting physician in the medical records, 33 RV leads were estimated to be septal and one apical. Estimated from the CT scan 9 leads were placed septal, 18 apical and 7 on the free wall. The mean geodesic distance between the initial site of activation in the 3D activation map and the marked RV insertion site from CT was 13.6 ±5.7 mm (range 4.3-28.6). The distance for each patient is shown in figure 2. The initial site of activation was constrained to the discrete nodes of the ventricular model whereas the marker for RV lead position was localized freely on the CT scan. The average distance from the RV CT marker to the nearest discrete node was 4.3 ±2.2 mm. Correcting for this error, the geodesic distance between the initial site of activation and RV CT marker was 9.3 ±5.4 mm (range 0.0-24.6). The average time used for 3D activation map computation was 1.1 ±0.4 s per ECG. Conclusions We demonstrated a novel non-invasive 12-lead ECG-based method to accurately and effectively localize the RV lead in relation to the ventricular anatomy during RV pacing. Furthermore, we confirmed that the RV lead was often implanted in an unintended position. With further advancements, this method has the potential to support physicians during pacemaker implantation to ensure optimal RV lead positioning. Further studies are needed to confirm the accuracy.

Predictive Value of Endoscopic Observations and Biopsy After Neoadjuvant Chemoradiotherapy in Assessing the Pathologic Complete Response of Patients With Esophageal Squamous Cell Carcinoma

IntroductionNo standard method has been defined to evaluate the therapeutic response of esophageal cancer to neoadjuvant chemoradiotherapy (CRT). This study aimed to determine the predictive value of endoscopic evaluation and biopsy after CRT in predicting the complete pathological response to neoadjuvant CRT in patients with esophageal squamous cell carcinoma (SCC).Materials and MethodThis prospective, descriptive study was conducted on patients with stage II and III esophageal SCC who could undergo esophagectomy. Patients underwent neoadjuvant CRT. Four to six weeks after the end of treatment, re-endoscopy was performed and a biopsy was taken in the presence of a tumor lesion. In the absence of a tumor lesion, the marked site of the esophagus was removed as a blind biopsy. Gastrologist observations during endoscopy and the result of the pathological examination of an endoscopic biopsy were recorded. The patient underwent esophagectomy. The pathology obtained from endoscopic biopsy was compared with the pathology response obtained from esophagectomy.ResultsSixty-nine patients were included in the study, of which 32 underwent esophagectomy. In an endoscopic examination after CRT, 28 patients had macroscopic tumor remnants and 4 patients did not. Pathological examination of the samples obtained from endoscopy showed no tumor remnants in 10 patients (31.3%), and in 22 patients (68.7%), living tumor remnants were seen in the biopsy specimen. Pathologic evaluation of the samples obtained by surgical resection showed that in 13 patients, there were no viable carcinomas in the esophagus or lymph nodes removed, and the rate of pathologic complete response was 40.6. Sensitivity, specificity, positive predictive, and negative predictive values of endoscopic observations were 94.7, 23, 64.2, and 75%, respectively. Preoperative biopsy sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 68.4, 30.7, 59, and 40%, respectively.ConclusionConsidering the negative and positive predictive values of endoscopic observations and biopsy after neoadjuvant CRT, it seems that these two methods alone are not suitable for assessing the pathologic complete response after neoadjuvant treatment.

Massage application to increase the spread of local anesthesia in sciatic nerve blocks: A cadaveric study

IntroductionSciatic nerve blocks are essential for surgical treatment of various lower limb pathologies. Due to the complexity and variation of anatomical landmarks, ultrasound (US) guided injection of local anesthesia has become common practice. In patients with thicker thigh girth (i.e., obese patients) excess tissue may distort US penetration thereby diminishing efficacy of the nerve block and/or cause severe post‐operative pain. Dye tracing techniques have been used to test the effectiveness of nerve blocks, but there is little research on using massage to manipulate anesthetic spread. Therefore, the aim of this study is to assess the effects of massage to manipulate local anesthesia spread in sciatic nerve blocks. We hypothesize massaging after injection will increase the spread of local anesthesia compared to non‐massage post injection.MethodsForty un‐fixed cadaveric legs were injected with a mixture of methylene blue dye and 2% Lidocaine Hydrochloride. Specimens were divided into non‐massage (control) (n=20) and massage (n=20) groups. Sciatic nerve blocks were performed by a nurse anesthetist using US guidance at the popliteal fossa traveling proximally until the sciatic nerve was identified and the location was tagged. Immediately following, massage group specimens received five repeated proximally directed massages with the US transducer head. Specimens from both groups were then dissected to expose the sciatic nerve. Measurements of the distance traveled from marked site of injection to proximal end of dyed area were measured and compared.ResultsSpread of local anesthesia in the inferior‐superior direction was significantly higher in the massage group than the control group (p≤0.05).ConclusionsMassaging post‐injection caused a greater spread of local anesthesia during sciatic nerve block.SignificanceSciatic nerve block techniques often utilize nerve stimulation to identify the sciatic nerve location. This may be due to lack of US penetration through the gluteus maximus muscle. In patients with thicker thigh girth due to subcutaneous fat, imaging visibility may be more difficult as well. Our findings suggest that clinicians may block the sciatic nerve at a more distal location with US guidance and manipulate the anesthesia to the region of interest.