Distal End Research Articles

Fracture risk analysis of a stylet-driven lead for left bundle branch area pacing using a human beating heart model

Abstract Background Left bundle branch area pacing (LBBAP) has emerged as a promising approach to cardiac physiologic pacing. However, the mechanical stress and fracture risk has not been studied for stylet-driven leads implanted in the left bundle branch area (LBBA). Purpose The main purpose of this study was to evaluate the change in curvature during a cardiac cycle when a stylet-driven lead with a rigid distal end was implanted in LBBA and to identify any increased risk of conductor fracture for the LBBAP lead compared to those implanted at the His bundle (HB), traditional right atrium (RA) and right ventricle (RV) locations. Methods A high-resolution, four-dimensional human beating heart model was utilized for simulating the stress on the lead. The bending stiffness of lead body segments was measured with 3-pts bending test and the values were assigned to the finite element model. The curvature change of lead body during one cardiac cycle was measured. The safety factor of lead conductors was calculated using the curvature measurements, the conductor’s endurance limit, and the ultimate stress of the material (MP35N). A higher safety factor indicates better lead durability and lower risk of fracture. A parametric study was also performed to investigate how additional implant factors impact the safety factor of LBBAP leads: lead insertion angle, implant depth, degree of slack, and implant location (Figure 1). Results A total of 8 implant scenarios for LBBAP were defined and tested using the combination of the implant factors described above. Two RV implanted locations were tested: RV apex and RV apical septum. One HBP and one RA implant location were tested. The region with maximum change in curvature for LBBAP lead was at 0-10 mm proximal to the ring electrode (Figure 2A). The maximum change in curvature on the lead body for LBBAP, HBP, RV, and RA implants were: 0.022±0.005 (n=8), 0.033 (n=1), 0.036±0.002 (n=2), and 0.024 mm-1 (n=1), respectively (Figure 2B). The safety factor for the lead conductors for LBBAP, HBP, RV, and RA implants were 5.57±1.35 (n=8), 3.48 (n=1), 4.62±0.04 (n=2), and 4.65 (n=1), respectively (Figure 2C). The highest safety factor among all implant locations was 7.63, corresponding to a LBBAP implant scenario with mid-septum location, a 45 degree lead insertion angle towards apex, 7.5 mm lead depth in the septum, and low lead slack. HBP had the lowest safety factor among all implant locations. Conclusion The stylet-driven lead with a rigid distal end implanted at the left bundle branch area does not introduce any further risk of fracture compared to the HBP or traditional RA/RV implant locations in this computational modeling study.Fig 1: LBBAP implants testedFig 2: Lead curvature and safety factor

Trismus caused by migration of orthodontic archwire into the infratemporal fossa: a case report.

Soft tissue injuries are known complications of orthodontic treatment. Most of the injuries are mild, but severe complications can arise from deeper penetration or dislodgement of brackets and other foreign bodies into the surrounding tissues of the oropharynx and infratemporal fossa. The patient, accompanied by his parents, presented to the Children's Emergency Department with the concern of gradual limitation of mouth opening and eventual trismus, which occurred over a span of 2 weeks. The patient presented with trismus and slight discomfort at the left cheek region. He reported a history of gradual limitation to his mouth opening 2 weeks prior. He was wearing upper and lower fixed orthodontic appliances and the left distal end of the maxillary archwire was found to have migrated into the left infratemporal fossa. Left medial pterygoid muscle inflammation, or bleeding and haematoma formation, or infection within the infratemporal region. The maxillary archwire was removed in the Children's Emergency Department and a computed tomography (CT) scan performed subsequently confirmed the diagnosis of left medial pterygoid muscle inflammation. The patient was started on an intravenous (IV) antibiotic and a 2-day course of IV dexamethasone to reduce the muscle inflammation. By the second day, the patient was able to achieve a mouth opening of 6 mm, and by the second week, the mouth opening had returned to normal. The potential risk of soft tissue injury and complications from orthodontic treatment is generally mild and limited. Soft tissue injuries can be avoided with careful management by the operator with the proper precautions taken. Clinicians should be familiar with the surrounding soft tissue anatomy and be aware of the potential for more severe complications and provide management or referral to the appropriate specialty accordingly.

Late coronary artery injury following chemoradiotherapy for thymic carcinoma: a case report

IntroductionSurgery remains the primary treatment modality for thymic carcinoma, with adjuvant radiotherapy being recommended to effectively mitigate local recurrence and metastasis rates subsequent to incomplete or complete resection. Chemoradiotherapy has the potential to induce coronary artery occlusion, thereby potentially impacting patients’ long-term survival rates. The existing literature currently lacks comprehensive research on the lesion characteristics of coronary artery injury resulting from chemoradiotherapy.Case presentationThe male patient, aged 55, was admitted to the hospital due to recurrent chest tightness and pain persisting for one week. Notably, the patient had previously undergone curative resection surgery for thymic carcinoma seven years ago. After the surgical procedure, the patient underwent a course of adjuvant chemotherapy comprising docetaxel and platinum. 11 months later, imaging examination diagnosed tumor recurrence, and concurrent chemoradiotherapy was administered at a total dose of 62 Gy/31F for planning gross target volume (PGTV) and 54 Gy/31F for planning target volume (PTV) with 2 cycles of paclitaxel and cisplatin. Re-admission of the patient occurred after a 7-year interval subsequent to the completion of concurrent chemoradiotherapy, leading to a subsequent diagnosis of acute non-ST segment elevation myocardial infarction. Following administration of antiplatelet, anticoagulant, and anti-myocardial ischemia therapy, coronary angiography revealed the presence of a bifurcation lesion at the distal end of the left main trunk. Intravascular ultrasound (IVUS) examination demonstrated significant negative remodeling of both the main trunk and its branches at the bifurcation site, characterized by minimal atherosclerotic plaque components.ConclusionsChemoradiotherapy may induce damage to endothelial cells, resulting in an inflammatory response. Negative remodeling of blood vessels is likely to occur, primarily characterized by vasoconstriction but with less atherosclerotic plaque burden. Routine stent implantation in negatively remodeled areas may lead to vascular rupture, necessitating intravascular imaging examination.

Males conditionally inseminate at three female body locations according to female mating history and female maturity status in a squid.

In some squids, such as those in the family Loliginidae, upon copulation, females receive and store male-delivered sperm capsules, spermatangia, at two different body locations: the buccal membrane and the distal end of the oviduct. This insemination site dimorphism is associated with alternative reproductive strategies. However, in Loliolus sumatrensis, a species of Loliginidae, the females possess three insemination sites: buccal membrane (BM), basal left IV arm (ARM) and lateral head behind the left eye (EYE), therefore we studied such the unusual phenomena. We developed microsatellite markers and genotyped the paternity of each spermatangium on three sites. We found multiple paternity at every single site and simultaneous usage of all three sites by a few males. The seasonal dynamics of a population in the Seto Inland Sea revealed a set priority for the initial use of insemination sites as BM, followed by ARM and then EYE, whereas the maximum number of stored spermatangia was greater in EYE > ARM > BM. Female maturity status was correlated with the usage pattern of insemination sites but not with the number of stored spermatangia at any insemination site. These results suggest that a male squid inseminates at different locations according to female mating history and female maturity status.

Rehabilitative outcomes with preparatory suction prostheses following traumatic Gritti-Stokes amputation: A case series.

Gritti-Stokes amputation (GSA) is a knee disarticulation variant, where the femur is transected at the level of the epicondyle and the patella is fixated to the distal end. GSA results in a long residual limb with little postoperative swelling and less potential for muscular atrophy, so stable limb volume may allow the use of seal-in suction for suspension for preparatory prostheses. The purpose of this case series was to report on the efficacy of seal-in suction preparatory prostheses for 2 adults with traumatic GSA. Between October and December of 2021, 2 participants with unilateral traumatic Gritti-Stokes amputation, who had received seal-in suction suspension for their preparatory prostheses, were recruited. Information was extracted from medical charts regarding prosthetic care and mobility at preparatory and definitive prosthesis evaluation, and participants underwent standardized measurement of their residual limb and prosthesis. Duration of preparatory prosthesis use was >6 months; neither participant reported loss of suspension nor significant complications with socket fit. Participant 1 required socket replacement because of residual limb pain secondary to osteophyte formation, and Participant 2 required component replacement because of weight gain. At definitive prosthesis evaluations, both participants were unlimited community ambulators; both successfully returned to work before provision of their definitive prostheses. Results indicate that seal-in suction suspension may be viable for preparatory prostheses among adults with traumatic GSA, but knee center height discrepancies persist. GSA may yield highly functional outcomes for adults with traumatic amputation. Further research is required to substantiate these findings.

Robotic Right Hepatectomy with En Bloc Caudatectomy for Bismuth IIIa Hilar Cholangiocarcinoma: A Video Demonstration of Left-Liver-First Anterior Radical Modular Orthotopic Right Hemihepatectomy.

Minimally invasive resection for perihilar cholangiocarcinoma is a complicated and technically demanding surgical procedure. Radical surgical resection is regarded as the best treatment for hepatic hilar cholangiocarcinoma.1,2 Right hepatectomy with caudate lobe resection is necessary as the treatment for bismuth IIIa hilar cholangiocarcinoma.3 The left-liver-first anterior radical modular orthotopic right hemihepatectomy (LARMORH), which can simplify surgical steps and decrease procedural difficulty, may be a better choice for Bismuth IIIa hilar cholangiocarcinoma.4 However, there are no reports of this approach using robotic technique for this operation. We will provide a detailed introduction to this method through this video. A 45-year-old female patient was diagnosed with a hilar cholangiocarcinoma. Following a 7-day percutaneous biliary drainage of the left intrahepatic bile duct and obtaining informed consent, we performed a robotic radical resection of the HCCA using the LARMORH approach. The patient was positioned supine with the entire bed elevated 20° and tilted 15° to the left. Trocars were placed in position (Fig. 1). After entering the abdominal cavity, it was explored for tumor metastasis. The surgery adopted a left approach, initially exploring the left hepatic artery and vein to further assess resectability. After confirming resectability, the right hepatic artery and gastroduodenal artery (GDA) were dissected. The common bile duct was dissected and transected at its distal end, ensuring R0 surgical margins. Lymph nodes were cleared from the foot side to the head side, confirming the metastasis to the lymph node group 13a, so we further cleared the group 16 and 9 lymph nodes.5 Subsequently, we approached the resection of the right half and the entire caudate lobe with the reverse thinking of left hepatic resection mode, preserving only the left branch of the portal vein and left hepatic artery, and dissecting the liver tissue along the resection plane of the left liver. After transection of the left hepatic duct, the activity space of the left liver was larger and the caudate lobe could be better exposed. The Spiegel lobe was lifted to the right in a "turn the page" fashion for in situ resection of the entire caudate lobe and the right half of the liver. Finally, a bilioenteric anastomosis was performed using the Roux-en-Y method. Robotic right hepatectomy with caudate lobectomy was successfully performed in 450 min, with an estimated blood loss of 200ml. The histological grading was determined as T1aN1M0 (stage IIIB) on the basis of postoperative pathological biopsy results. The patient achieved a satisfactory postoperative recovery and was discharged on the 14th postoperative day without any major complications. Following the operation, the patient received capecitabine chemotherapy according to the Chinese Society of Clinical Oncology (CSCO) criteria. Since September 2022, our team has completed three radical resections for Bismuth IIIa HCCA using this technique. All patients achieved a satisfactory postoperative recovery without any further complications. Robotic left-liver-first anterior radical modular orthotopic right hemihepatectomy for Bismuth IIIa HCCA is both safe and feasible. This method may provide a new surgical approach for patients with type IIIA HCCA or liver diseases requiring right hemihepatectomy combined with total caudate lobectomy.

Options to apply national developments in the assessment of sentinel lymph node involvement in breast cancer

Background. Breast cancer is the leading oncopathology of women. The routine radical surgery performed in this pathology includes lymph node dissection, which provokes development of postmastectomy syndrome. However, the removal of non-metastatic lymph nodes is not rational according to the subsequent disability of the patients. This can be avoided by using a sentinel lymph node (SLN) biopsy procedure. At this stage of oncology development, there are several ways to visualize SLN. The fluorescent method is among the most promising. This technique has been used for many years. However, it is not sufficiently implemented in clinical practice. There are still several questions about the procedure for its performance. In addition, it requires the introduction and improvement of domestic developments, including reducing financial costs.Aim. To study the use of indocyanine green of domestic production (LLC Firm “FERMENT”, Russia) and the IC-GOR detection system (LLC “MedKomplekt”, Russia) for SLN biopsy in patients with early breast cancer.Materials and methods. From February to September 2023, biopsy of SLN using indocyanine green (LLC Firm “FERMENT”, Russia) was performed in 53 patients with early breast cancer without clinically detectable lesion of regional lymph nodes. In all cases, according to the clinical examination, the patients had an operable stage of breast cancer (cT1–3N0M0). 5 mg of indocyanine green, dissolved in 4 ml of water for injection, was administered after sanitizing of the surgical field intradermally and subcutaneously at 2 points in the upper-outer quadrant of the breast along the edge of the areola in 40 patients (75.5 %) or paratumorally in 13 patients (24.5 %). An incision in the axilla about 4 cm long was made no earlier than 10–15 minutes after injection of indocyanine green (when visualizing the track 1 cm beyond its distal end to avoid crossing the lymph duct, after which the drug can flow into the wound). After imaging, all detected lymph nodes were removed for planned morphological examination. Standard lymph node dissection of 1 and 2 level was performed in all patients. Middle age of patients was 64.5 years (from 37 to 85 year). In 40 patients (75.5 %) modified radical mastectomy was performed, breast conserving surgery was done in 13 cases (24.5 %).Results. SLN were visualized in 51 patients out of 53 (96.2 %). After the final morphological examination, the majority of patients in the group were ranged in the IA and IIA stages of the disease – 15 (28.3 %) and 28 (52.8 %), respectively. Metastasis in the SLN were found in 9 patients (17.0 %). Besides, in 3 cases (5.7 %) metastasis in the lymph nodes were found after lymph node dissection. In 4 cases (7.6 %) metastasis were found during lymph node dissection but were not detected in the removed SLN. Thus, in the study group 13 (24.5 %) patients had metastatic lymph node lesion despite negative clinical status. The total number of removed SLN in the study group was 169 (from 1 to 6), the average number of removed lymph nodes was 3.3. Any negative events, allergic and general reactions to indocyanine were not reported.Conclusion. Our technique of contrasting SLN with indocyanine green is adequate and reproducible. The frequency of detection of SLN with this method is 96.2 %, with an acceptable level of false negative results is 7.6 %. Indocyanine green (LLC Firm “FERMENT”, Russia) and the LED fluoroscopic cancer detector IC-GOR (LLC “MedKomplekt”, Russia) can be recommended for performing a SLN biopsy.

Structural insights into the distinct protective mechanisms of human antibodies targeting ZIKV NS1

Antibodies targeting non-structural protein 1 (NS1) confer protection against Zika virus (ZIKV). Although monoclonal antibodies (MAbs) 3G2 and 4B8 are more potent than MAb 4F10 in suppressing ZIKV infection in neonatal mice models, the epitopes are unclear. Herein, we determined the Cryo-electron microscopy (Cryo-EM) structures of ZIKV NS1 in complex with five human antibodies at 2.6–2.9 Å resolution. Group I antibodies (3G2 and 4B8) recognize the previously unreported epitopes on the outer surface of the NS1 dimer. The unique binding mode of Group I antibodies led to a stronger recognition of the cell surface form of NS1 and completely inhibited secreted form non-structural protein 1 (sNS1)-induced endothelial permeability via their immunoglobulin G (IgG) and Fab. Group II antibodies (4F10, 2E11, and 14G5) recognize common epitopes in the distal end of the β-ladder domain, with a blockade efficiency that may be related to their affinity for the sNS1 protein and the presence of full-length IgG. These findings elucidate the correlation between epitope recognition and protective efficacy of anti-NS1 antibodies and highlight the diagnostic and therapeutic potential of 3G2 and 4B8.

A Tension Sensor Array for Cable-Driven Surgical Robots.

Tendon-sheath structures are commonly utilized to drive surgical robots due to their compact size, flexibility, and straightforward controllability. However, long-distance cable tension estimation poses a significant challenge due to its frictional characteristics affected by complicated factors. This paper proposes a miniature tension sensor array for an endoscopic cable-driven parallel robot, aiming to integrate sensors into the distal end of long and flexible surgical instruments to sense cable tension and alleviate friction between the tendon and sheath. The sensor array, mounted at the distal end of the robot, boasts the advantages of a small size (16 mm outer diameter) and reduced frictional impact. A force compensation strategy was presented and verified on a platform with a single cable and subsequently implemented on the robot. The robot demonstrated good performance in a series of palpation tests, exhibiting a 0.173 N average error in force estimation and a 0.213 N root-mean-square error. In blind tests, all ten participants were able to differentiate between silicone pads with varying hardness through force feedback provided by a haptic device.

Ex vivo validation of magnetically actuated intravascular untethered robots in a clinical setting

Intravascular surgical instruments require precise navigation within narrow vessels, necessitating maximum flexibility, minimal diameter, and high degrees of freedom. Existing tools often lack control during insertion due to undesirable bending, limiting vessel accessibility and risking tissue damage. Next-generation instruments aim to develop hemocompatible untethered devices controlled by external magnetic forces. Achieving this goal remains complex due to testing and implementation challenges in clinical environments. Here we assess the operational effectiveness of hemocompatible untethered magnetic robots using an ex vivo porcine aorta model. The results demonstrate a linear decrease in the swimming speed of untethered magnetic robots as arterial blood flow increases, with the capability to navigate against a maximum arterial flow rate of 67 mL/min. The untethered magnetic robots effectively demonstrate locomotion in a difficult-to-access target site, navigating through the abdominal aorta and reaching the distal end of the renal artery.

Application of mixed reality technology in free fibular flap transplantation for repairing mandibular defects

To explore the feasibility and effectiveness of mixed reality technology for localizing perforator vessels in the repair of mandibular defects using free fibular flap. Between June 2020 and June 2023, 12 patients with mandibular defects were repaired with free fibular flap. There were 8 males and 4 females, with an average age of 61 years (range, 35-78 years). There were 9 cases of ameloblastomas and 3 cases of squamous cell carcinomas involving the mandible. The disease duration ranged from 15 days to 2 years (median, 14.2 months). The length of mandibular defects ranged from 5 to 14 cm (mean, 8.5 cm). The area of soft tissue defects ranged from 5 cm×4 cm to 8 cm×6 cm. Preoperative enhanced CT scans of the maxillofacial region and CT angiography of the lower limbs were performed, and the data was used to create three-dimensional models of the mandible and lower limb perforator vessels. During operation, the mixed reality technology was used to overlay the three-dimensional model of perforator vessels onto the body surface for harvesting the free fibular flap. The length of the fibula harvested ranged from 6 to 15 cm, with a mean of 9.5 cm; the size of the flap ranged from 6 cm×5 cm to 10 cm×8 cm. The donor sites were sutured directly in 7 cases and repaired with free skin grafting in 5 cases. Thirty perforator vessels were located by mixed reality technology before operation, with an average of 2.5 vessels per case; the distance between the exit point of the perforator vessels located before operation and the actual exit point ranged from 1 to 4 mm, with a mean of 2.8 mm. All fibular flaps survived; 1 case had necrosis at the distal end of flap, which healed after dressing changes. One donor site had infection, which healed after anti-inflammatory dressing changes; the remaining incisions healed by first intention, and the grafts survived smoothly. All patients were followed up 8-36 months (median, 21 months). The repaired facial appearance was satisfactory, with no flap swelling. Among the patients underwent postoperative radiotherapy, 2 patients had normal bone healing and 1 had delayed healing at 6 months. In free fibular flap reconstruction of mandibular defects, the use of mixed reality technology for perforator vessel localization can achieve three-dimensional visualization, simplify surgical procedures, and reduce errors.

Identification of 30 transition fibre proteins in Trypanosoma brucei reveals a complex and dynamic structure.

Transition fibres and distal appendages surround the distal end of mature basal bodies and are essential for ciliogenesis, but only a few of the proteins involved have been identified and functionally characterised. Here, through genome-wide analysis, we have identified 30 transition fibre proteins (TFPs) and mapped their arrangement in the flagellated eukaryote Trypanosoma brucei. We discovered that TFPs are recruited to the mature basal body before and after basal body duplication, with differential expression of five TFPs observed at the assembling new flagellum compared to the existing fixed-length old flagellum. RNAi-mediated depletion of 17 TFPs revealed six TFPs that are necessary for ciliogenesis and a further three TFPs that are necessary for normal flagellum length. We identified nine TFPs that had a detectable orthologue in at least one basal body-forming eukaryotic organism outside of the kinetoplastid parasites. Our work has tripled the number of known transition fibre components, demonstrating that transition fibres are complex and dynamic in their composition throughout the cell cycle, which relates to their essential roles in ciliogenesis and flagellum length regulation.

Exosomes-carried curcumin based on polysaccharide hydrogel promote flap survival

Flap grafting is a common technique used to repair skin defects in orthopedics and plastic and reconstructive surgeries. However, oxidative stress injury caused by ischemia and ischemia-reperfusion injury at the distal end of the skin flap can cause flap necrosis. Curcumin is a natural compound with anti-inflammatory and antioxidant properties that tackle oxidative stress. However, its applicability is limited by its poor water solubility. Exosomes are membranous vesicles that can be loaded with hydrophobic drugs. They are widely studied in drug delivery applications and can be investigated to augment curcumin efficiency. In this study, a self-healing oxidized pullulan polysaccharide-carboxymethylated chitosan composite hydrogel was used as a curcumin-loaded exosome delivery system to evaluate its impact on the viability of skin flaps. The hydrogel exhibited good self-healing properties that allowed the continuous and stable release of drugs. It had anti-inflammatory and antioxidant properties that could reduce oxidative stress damage due to early ischemia and hypoxia of the skin flap in vitro. Moreover, this composite hydrogel attenuated inflammatory responses, promoted angiogenesis, and reduced the distal necrosis of the flap in vivo. Therefore, our hydrogel provides a novel strategy for skin flap graft protection with reduced necrosis and the potential for broad clinical applications.

Organic matter enrichment in basin periphery: A case study of Wufeng-Longmaxi shale, Marcellus shale, and Ohio shale

Our study investigates organic matter (OM) enrichment at the peripheries of marine basins, contrasting with prior research focused on central regions. We analyze three shale formations at three distinct deposition sites: the Marcellus (M) shale near an orogenic belt, and the Wufeng-Longmaxi (WL) shale, the Ohio (O) shale adjacent to a forebulge uplift. By examining factors such as redox conditions, clastic input, paleoproductivity, sedimentary facies and geological activities, we identify that the OM enrichment in shale (M shale) near the orogen resulted from significant inputs of river detritus and semi-deep shelf environment. Additionally, local enrichment is primarily influenced by volcanic ash sedimentation. The shale (O shale) at the distal end of the forebulge shows high OM concentration due to its stable deep-water shelf environment. Local enrichment in this area is caused by sediment re-sedimentation and glaciation. Similarly, the shale (WL shale) at the proximal end also exhibits a high OM concentration due to its stable deep-water shelf environment. In this case, volcanic ash deposition and transgression are responsible for the local enrichment. Our findings reveal how paleogeography and geological activities impact OM enrichment in basin peripheries, while also offering insights into evaluating shale gas reservoirs.

An altered gut microbiome in pre-eclampsia: cause or consequence.

Hypertensive disorders of pregnancy, including pre-eclampsia, are a leading cause of serious and debilitating complications that affect both the mother and the fetus. Despite the occurrence and the health implications of these disorders there is still relatively limited evidence on the molecular underpinnings of the pathophysiology. An area that has come to the fore with regard to its influence on health and disease is the microbiome. While there are several microbiome niches on and within the body, the distal end of the gut harbors the largest of these impacting on many different systems of the body including the central nervous system, the immune system, and the reproductive system. While the role of the microbiome in hypertensive disorders, including pre-eclampsia, has not been fully elucidated some studies have indicated that several of the symptoms of these disorders are linked to an altered gut microbiome. In this review, we examine both pre-eclampsia and microbiome literature to summarize the current knowledge on whether the microbiome drives the symptoms of pre-eclampsia or if the aberrant microbiome is a consequence of this condition. Despite the paucity of studies, obvious gut microbiome changes have been noted in women with pre-eclampsia and the individual symptoms associated with the condition. Yet further research is required to fully elucidate the role of the microbiome and the significance it plays in the development of the symptoms. Regardless of this, the literature highlights the potential for a microbiome targeted intervention such as dietary changes or prebiotic and probiotics to reduce the impact of some aspects of these disorders.

Finite element analysis of modified Slongo's external fixation in the treatment of supracondylar humeral fractures in older children.

Older children over 8 years old are at higher risk of elbow joint stiffness after treatment of supracondylar humeral fractures. The objective of this study was to improve the Slongo's external fixation system for treating supracondylar humeral fractures in older children. This would be achieved by increasing fixation strength and providing a theoretical basis through finite element analysis and mechanical testing. A 13-year-old female patient with a history of previous fracture was selected for CT data processing to create a three-dimensional model of the distal humerus fracture. Two internal fixation models were established, using the Slongo's external fixation method with Kirschner wire (Group A) and modifying the Slongo's external fixation (Kirschner wire tail fixation) (Group B). The fracture models were then subjected to mechanical loading analysis using Finite Element Analysis Abaqus 6.14 software to simulate separation, internal rotation, and torsion loads. A PVC humeral bone model was used to create a supracondylar fracture model, and the A and B internal fixation methods were applied separately. The anterior-posterior and torsional stresses were measured using the Bose Electroforce3510 testing system, followed by a comparative analysis. The finite element simulation results showed that under the same tensile, torsion, and inversion forces, the osteotomy model fixed with Kirschner wire at the distal end in Group B exhibited smaller tensile stress and deformation compared to the unfixed osteotomy model in Group A. This indicated that the fixation strength of Group B was superior to that of Group A. According to the test results of the Bose Electroforce3510 testing system, a simple linear regression analysis was conducted using SPSS software. The K values of rotation angle-torque tests and front and rear displacement-stress tests were calculated for Groups A and B, with Group B showing higher values than Group A. The results of this study supported the significantly enhanced biomechanical reliability and stability of fracture fixation in Group B, which utilized the modified Slongo's external fixation (Kirschner wire tail fixation). This optimized method provides a new choice for the clinical treatment of supracondylar humeral fractures in older children, backed by both clinical evidence and theoretical basis.

Experience with Gore’s Block in Patients with Lower Lumbar Radiculopathy

Abstract Lower lumbar radiculopathy is one of the most common presentations in the pain clinic outpatient department (OPD). A thorough history, physical examination, neurological assessment, and imaging help in the diagnosis and management. The inability to identify the correct pain generator often causes a failure of treatment. Dr. Satishchandra Gore has proposed a new method for the diagnosis of affected lower lumbar nerve root (L5 and S1) at a peripheral level. His hypothesis is that in an inflamed nerve root, sodium channels are upregulated at both proximal and distal ends (central and peripheral). This results in tenderness at the distal peripheral end of the nerve on palpation. We can block the sodium channels at the distal portion of the same inflamed nerve, which may be able to abolish pain. This procedure is called “Gore’s Block” and the result is called “Gore’s sign.” We used this technique in 10 patients with suspected L5-S1 radiculopathy. Out of 10 patients, seven patients had pain relief after Gore’s block. These seven patients also responded well to a Caudal epidural steroid injection. Two patients did not have significant pain relief with Gore’s block and had poor responses to epidural steroid injections. One patient got therapeutic pain relief after Gore’s block, probably due to the natural resolution of the disease. Gore’s block is a simple, OPD procedure, helpful in diagnosing the level of nerve affection in lower lumbar radiculopathy. It is diagnostic and has a good correlation with epidural blocks. Whether it is therapeutic in nature needs to be further investigated.

Dispersal and connectivity in increasingly extreme climatic conditions.

While climate change has been shown to impact several life-history traits of wild-living animal populations, little is known about its effects on dispersal and connectivity. Here, we capitalize on the highly variable flooding regime of the Okavango Delta to investigate the impacts of changing environmental conditions on the dispersal and connectivity of the endangered African wild dog (Lycaon pictus). Based on remote sensed flood extents observed over 20 years, we derive two extreme flood scenarios: a minimum and a maximum flood extent, representative of very dry and very wet environmental periods. These conditions are akin to those anticipated under increased climatic variability, as it is expected under climate change. Using a movement model parameterized with GPS data from dispersing individuals, we simulate 12,000 individual dispersal trajectories across the ecosystem under both scenarios and investigate patterns of connectivity. Across the entire ecosystem, surface water coverage during maximum flood extent reduces dispersal success (i.e., the propensity of individuals to disperse between adjacent subpopulations) by 12% and increases dispersal durations by 17%. Locally, however, dispersal success diminishes by as much as 78%. Depending on the flood extent, alternative dispersal corridors emerge, some of which in the immediate vicinity of human-dominated landscapes. Notably, under maximum flood extent, the number of dispersing trajectories moving into human-dominated landscapes decreases by 41% at the Okavango Delta's inflow, but increases by 126% at the Delta's distal end. This may drive the amplification of human-wildlife conflict. While predicting the impacts of climate change on environmental conditions on the ground remains challenging, our results highlight that environmental change may have significant consequences for dispersal patterns and connectivity, and ultimately, population viability. Acknowledging and anticipating such impacts will be key to effective conservation strategies and to preserve vital dispersal corridors in light of climate change and other human-related landscape alterations.

Abdominal hysterectomy due to uterine rupture causing bilateral ureterovaginal fistula: A rare case report

Abstract Ureterovaginal fistula (UVF) is defined as abnormal communication between ureter and vagina. Although documented after radical hysterectomy, post radiation and retained pessary incidence of bilateral UVF is still very rare. We have documented a case report of a multipara woman presented with persistent urinary leakage following an emergency hysterectomy for obstructed labor. After evaluation with imaging there was bilateral hydroureterophrosis with dense purulent collection mixed with contrast in the vesicular area with lower end of ureter draining in the vaginal vault with preserved renal function. During exploration both ureters were dilated. Instillation dye in both ureters showed extravasation in vagina. After ligating distal ends modified Lich-Gregoir technique done over double J (DJ) stents. DJ removed after 3 months. Bilateral UVF is only 5%–10% of all ureteric injury. Aggressive blind clamping, excessive hemorrhage, distorted anatomy, malignancy and surgeons experience play a crucial role. Obstetric cause is the prime factor. Preventing measures like proper screening of antenatal patients, early detection of high-risk pregnancy, supervised caesarean section should be taken to avoid ureteric injuries

Myofilament calcium sensitization in non-human primate lower esophageal sphincter and esophagus

Background/Objectives: Peristalsis in the esophagus (ESO) moves ingested contents into the stomach. The lower esophageal sphincter (LES) is located at the distal end of the ESO and generates tone to prevent reflux of gastric contents. Previous studies suggest that the expression and/or phosphorylation of proteins involved in myofilament Ca2+ sensitization differs between phasic and tonic smooth muscles (Brozovich et al., 2016; PMID: 27037223). We hypothesize that differences in expression and/or phosphorylation of these proteins contributes to differences in contractile activity between LES and ESO. The aims were to 1) characterize contractile activity in Cynomolgus monkey LES and ESO, 2) evaluate myofilament Ca2+ sensitization protein expression and phosphorylation, 3) examine changes in phosphorylation when contractile activity is enhanced or inhibited pharmacologically. Methods: Contraction was assessed in strips of LES and ESO by isometric tension recordings. Carbachol (CCh, 1 μM) was used to enhance contractions. ROCK2 (SR3677; 2 μM) or CavL (nifedipine; 1 μM) antagonists were used to inhibit contractions. Tissues were snap frozen in liquid nitrogen after peak response and prepared for protein expression analysis using Jess immunoelectrophoresis. Results: Under basal conditions, the LES exhibited tone whereas the ESO had phasic activity. CCh significantly increased contractions. Nifedipine and SR3677 significantly decreased basal and CCh-induced contractions with nifedipine having the greater effect. MLCK and MYPT1 expression was significantly greater in LES than ESO while LC20 and CPI-17 expression was greater in ESO. ROCK2 expression was similar in LES and ESO. Under basal conditions MYPT1 and LC20 phosphorylation was greater in LES. MYPT1 and LC20 phosphorylation was decreased by SR3677 but not nifedipine in both tissues. CCh increased MYPT1 and LC20 phosphorylation in both tissues though was greater in LES. SR3677 inhibited phosphorylation of both proteins in LES and ESO. Discussion/Conclusions: The differences in expression and phosphorylation of key proteins involved in myofilament Ca2+ sensitization likely contribute to differences in contractile activity. Notably, there is greater LC20 phosphorylation in LES than ESO under basal conditions and with CCh. Furthermore, there is an important role for ROCK2 in regulating basal contractile activity in LES and ESO as both contraction and phosphorylation of MYPT1 and LC20 are reduced by SR3677. While nifedipine significantly reduced contractile activity in LES and ESO, it did not reduce phosphorylation of MYPT1 indicating that the ROCK2 pathway is independent of Ca2+ influx. These findings may improve understanding of the pathophysiology associated with esophageal dysmotility. NIH DK129528 to CAC. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.