Live Porcine Research Articles

Standardization of transthoracic impedance values for estimating heart failure and its utility

Abstract Background The use of intrathoracic impedance for examining pleural effusion in heart failure patients has been explored previously. However, due to concerns about its accuracy and complexity, transthoracic impedance values have had limitations in quantifying extravascular lung water. Our dual objectives were to clarify the relationship between intrathoracic conditions and percutaneous transthoracic impedance values, and to establish a basic model for a new machine learning-based estimation system for assessing intrathoracic conditions in patients with heart failure. Methods First, we developed a live porcine congested lung model that induced pleural effusion by substantial fluid loading, and then longitudinally evaluated its correlation with percutaneous transthoracic impedance values. Second, we conducted multi-frequency bioelectrical impedance analysis to simultaneously collect electrical, physical, and hematological data from 63 hospitalized heart failure patients and 82 healthy volunteers Results In the porcine model, pleural effusion correlated with a concurrent decrease in SpO2 and a gradual decrease in impedance. We indexed and generated features from the measured values and developed an intrathoracic estimation model based on electrical measurements and clinical findings using a decision tree-based machine learning approach. Among the 286 features collected per individual, the model used 16 features. Notably, the model demonstrated high accuracy in discriminating patients with pleural effusion, achieving an AUC of 0.905 (95% CI: 0.870-0.940) in cross-validation, significantly outperforming the conventional frequency-based method. Conclusions Transthoracic impedance values, when indexed, reflect intrathoracic conditions and improve estimation. Our results highlighted the potential of machine learning and thoracic impedance measurement for accurate estimation of pleural effusion. This approach provides an effective means of assessing intrathoracic conditions. Figure: The upper figure shows the relationship between impedance values and pleural effusion in the congested lung model. On these results, human data were collected to construct the estimation model. The lower illustrates the accuracy of the model and provides a comprehensive view of the system.

In vitro and in vivo evaluation of a novel wired transmission pH-combined photographic catheter for ambulatory gastroesophageal reflux monitoring (with videos).

Twenty-four-hour pH-impedance monitoring is an important diagnostic approach for gastroesophageal reflux disease (GERD). Reflux monitoring results cannot be synchronized with ambulatory motility imaging of the esophageal sphincter. We have designed a novel wired transmission pH-combined photographic catheter (WT-CPC) for the synchronous acquisition of reflux image and pH. Different patterns of reflux events were simulated to perform in a porcine gastroesophageal reflux model in vitro. The live porcine model of gastroesophageal reflux was established in three Bama pigs. Monitoring was conducted with the WT-CPC and pH-impedance catheter simultaneously. Measurements included the number and proportion of reflux events, as well as acid exposure time (AET). The detection rates of WT-CPC for distal and horizontal acid reflux events were significantly higher compared to those of pH-impedance catheters (100% vs. 14.29%, 100% vs. 57.14%, P < 0.05). There was no significant difference between the two methods in proximal acid reflux events (P = 0.217). Regarding mixed reflux events, WT-CPC exhibited higher detection rates for distal events than pH-impedance catheter (100% vs. 42.86%, P < 0.05). However, there was no significant difference between the two methods for proximal reflux events (P > 0.05). Both methods showed similar results for horizontal reflux events. A porcine gastroesophageal reflux model was successfully established and utilized for reflux monitoring. A total of 28 episodes of reflux were detected within 6.5min. The detection rate achieved by WT-CPC for reflux events was significantly higher than that obtained by pH-impedance (100% vs. 78.57%, P = 0.023). The WT-CPC has demonstrated reflux monitoring capabilities in an isolated reflux organ model. It also showed good operability and performance in the porcine model. The WT-CPC holds promising potential to provide valuable diagnostic evidence for GERD.

Efficacy of robot arm-assisted endoscopic submucosal dissection in live porcine stomach (with video)

Endoscopic submucosal dissection (ESD) is technically challenging and requires a high level of skill. However, there is no effective method of exposing the submucosal plane during dissection. In this study, the efficacy of robot arm-assisted tissue traction for gastric ESD was evaluated using an in vivo porcine model. The stomach of each pig was divided into eight locations. In the conventional ESD (C-ESD) group, one ESD was performed at each location (N = 8). In the robot arm-assisted ESD (R-ESD) group, two ESDs were performed at each location (N = 16). The primary endpoint was the submucosal dissection speed (mm2/s). The robot arm could apply tissue traction in the desired direction and successfully expose the submucosal plane during submucosal dissection in all lesion locations. The submucosal dissection speed was significantly faster in the R-ESD group than in the C-ESD group (p = 0.005). The blind dissection rate was significantly lower in the R-ESD group (P = 0.000). The robotic arm-assisted traction in ESD enabled a significant improvement in submucosal dissection speed, blind dissection rate which suggests the potential for making ESD easier and enhancing procedural efficiency and safety.

Spectral characterization of intraoperative renal perfusion using hyperspectral imaging and artificial intelligence

Accurate intraoperative assessment of organ perfusion is a pivotal determinant in preserving organ function e.g. during kidney surgery including partial nephrectomy or kidney transplantation. Hyperspectral imaging (HSI) has great potential to objectively describe and quantify this perfusion as opposed to conventional surrogate techniques such as ultrasound flowmeter, indocyanine green or the subjective eye of the surgeon. An established live porcine model under general anesthesia received median laparotomy and renal mobilization. Different scenarios that were measured using HSI were (1) complete, (2) gradual and (3) partial malperfusion. The differences in spectral reflectance as well as HSI oxygenation (StO2) between different perfusion states were compelling and as high as 56.9% with 70.3% (± 11.0%) for “physiological” vs. 13.4% (± 3.1%) for “venous congestion”. A machine learning (ML) algorithm was able to distinguish between these perfusion states with a balanced prediction accuracy of 97.8%. Data from this porcine study including 1300 recordings across 57 individuals was compared to a human dataset of 104 recordings across 17 individuals suggesting clinical transferability. Therefore, HSI is a highly promising tool for intraoperative microvascular evaluation of perfusion states with great advantages over existing surrogate techniques. Clinical trials are required to prove patient benefit.

Real-time surgical simulation training for recurrent laryngeal nerve and facial nerve dissection

BackgroundHead and neck surgical simulation training (SST) is an important part in otolaryngology head and neck surgical education. In this study, we provide a live porcine model for SST in recurrent laryngeal nerve (RLN) and facial nerve (FN) dissection for otolaryngology head and neck residents. MethodsA lecture with surgical manual is provided to illustrate the surgical landmarks of pig, and step-by-step procedures for thyroid and parotid surgery, as well as neck dissection. We used 4-month-old pig weighting 32 kg for the SST. The mentor demonstrated result of RLN injury with continuous nerve monitoring. Participants used monopolar stimulation probe (4 pulse/s, 100 μs, 3-8 mA; Medtronic) to identify and intermittent monitor the RLN and FN during the SST. After the dissection course, we conducted a questionnaire survey to check the effectiveness of this training model. ResultsTotal 30 participants were recruited, including 16 female and 14 male resident doctors. There were 1, 4 and 25 learners for 3rd year, 4th and 5th years residents, respectively. Before this training course, 53 % (16/30) and 63 % (19/30) had successful experience in finding the RLN and FN, respectively. After the SST, all of our participants had successful identify the RLN and FN (p-value <0.01); all had positive response to stimulation and familiar with the procedure. ConclusionsThe live porcine model is effectiveness in SST for RLN and FN dissection. Live porcine model with real-time RLN and FN monitoring should be provided for otolaryngology head and neck resident training.

Crystalloid volume versus catecholamines for management of hemorrhagic shock during esophagectomy - assessment of microcirculatory tissue oxygenation of the gastric conduit in a porcine model using hyperspectral imaging - an experimental study.

Oncologic esophagectomy is a two-cavity procedure with considerable morbidity and mortality. Complex anatomy and the proximity to major vessels constitute a risk for massive intraoperative hemorrhage. Currently, there is no conclusive consensus on the ideal anesthesiologic countermeasure in case of such immense blood loss. The objective of this work was to identify the most promising anesthesiologic management in case of intraoperative hemorrhage with regards to tissue perfusion of the gastric conduit during esophagectomy using hyperspectral imaging (HSI). An established live porcine model (n=32) for esophagectomy was used with gastric conduit formation and simulation of a linear stapled side-to-side esophagogastrostomy. After a standardized procedure of controlled blood loss of about 1 L per pig, the four experimental groups (n=8 each) differed in anesthesiologic intervention i.e. (I) permissive hypotension, (II) catecholamine therapy using noradrenaline, (III) crystalloid volume supplementation and (IV) combined crystalloid volume supplementation with noradrenaline therapy. HSI tissue oxygenation (StO2) of the gastric conduit was evaluated and correlated with systemic perfusion parameters. Measurements were conducted before (T0) and after (T1) laparotomy, after hemorrhage (T2) and 60 minutes (T3) and 120 minutes (T4) after anesthesiologic intervention. StO2 values of the gastric conduit showed significantly different results between the four experimental groups with 63.3% (±7.6%) after permissive hypotension (I), 45.9% (±6.4%) after catecholamine therapy (II), 70.5% (±6.1%) after crystalloid volume supplementation (III) and 69.0% (±3.7%) after combined therapy (IV). StO2 values correlated strongly with systemic lactate values (r=-0.67; CI -0.77 to -0.54), which is an established prognostic factor. Crystalloid volume supplementation (III) yields the highest StO2 values and lowest systemic lactate values and therefore appears to be the superior primary treatment strategy after hemorrhage during esophagectomy with regards to microcirculatory tissue oxygenation of the gastric conduit.

Histopathologic Study of the Effects of Surgically Applied Cryoanalgesia on Intercostal Nerves in a Live Porcine Model.

Background/Objectives: The aim of this study was to establish a histologic baseline for cryoanalgesia of 2 min duration and evaluate the effects of different freeze durations. Methods: A porcine model was used in which the application of bilateral cryoanalgesia from intercostal spaces T3-T7 was completed via partial median sternotomy. The animals were kept alive for 7 days and the ribcages were sent to a specialized center for histopathologic analysis of the freezing injury. Results: Forty freezing lesions were completed and analyzed histologically. Thirty-eight (95%) of the cryo-lesions presented 100% nerve fiber degeneration at or distal to the ablation site, with preservation of the perineural connective tissue, as intended. The two unaffected nerves were found to be physically located outside of the freezing area. Conclusions: The complete axonal degeneration with preservation of the perineural tissue opens the possibility to shorter freezing times than the recommended 2 min. Visualization of the nerve and positioning of the probe is important in ensuring the proper effect on the nerve. This histologic analysis confirms the process triggered by cryoanalgesia that, until now, had only been assumed.

Glaucoma surgery experiments using digital microscope-integrated optical coherence tomography and OCT-compatible instruments

There is a certain failure rate in traditional glaucoma surgery because of the lack of depth information in microscope images. In this work, we present a digital microscope-integrated optical coherence tomography (MIOCT) system and several custom-made OCT-compatible instruments for glaucoma surgery. Sixteen ophthalmologists were asked to perform trabeculectomy and canaloplasty on live porcine eyes using the system and instruments. After surgery, a subjective feedback survey about the user experience was taken. The experiment results showed that our system can help surgeons easily locate important tissue structures during surgery. The custom-made instruments also solved the shadowing problem in OCT imaging. Surgeons preferred to use the system in their future practice.

Subcostal bilateral internal thoracic artery harvesting with the da Vinci Single Port system: an experimental feasibility study.

We evaluated the feasibility of harvesting bilateral internal thoracic arteries with the da Vinci Single Port system (SP)through a single left-sided subcostal incision. Complete bilateral mobilization with sufficiently long conduits for multivessel grafting was possible in 2 human cadavers and 2 live porcine. Creating the subcostal access and docking the SP system took between 14 and 21 min and the total harvest time ranged from 65 to 125 min in all models. No major bleeding was observed in the live porcine and hemostasis was managed with the available instrumentation. One porcine deceased during surgery due to ventricular fibrillation followed by cardiac arrest. The robotic harvesting was technically easily reproduced by the surgeons and required no additional rib-spreading. Further studies will be required to assess if this subcostal approach with the da Vinci SP system yields true clinical benefits in patients.

The ERUS course on robot-assisted kidney transplantation

PurposeRobot-assisted kidney transplantation (RAKT) is being increasingly performed at selected referral institutions worldwide. Yet, surgical training in RAKT is still unstructured and not grounded into formal credentialing courses including simulation, lab facilities, and modular training with animal models. As such, developing standardized, modular training programs is warranted to provide surgeons with the RAKT-specific skillset needed for a “safe” learning curve.MethodsThe 3-day course on RAKT developed at the EAU Skills Center in Orsi Academy was designed as a standardized, modular, step-by-step approach aiming to provide theoretical and practical skills. The course is held by expert proctors with extensive experience in RAKT. To maximize the course’s usefulness, a solid knowledge of robotics and transplantation is desirable for participants.ResultsFrom January 2016 to July 2023, 87 surgeons from 23 countries (of which 36% from extra-European countries) participated in the RAKT course performed at the EAU Skills Center in Orsi Academy. Of these, 58/87 (67%) were urologists, while 27/87 (31%) were general surgeons and 2/87 (2%) were vascular surgeons. To date, 18 participants (20.6%) are actively involved in RAKT programs at institutions included in the European Association of Urology (EAU) Robotic Urology Section (ERUS)–RAKT network.ConclusionLeveraging the potential of simulation, wet-lab training, live porcine models, and experienced proctors, the RAKT course performed at the EAU Skills Center in Orsi Academy represents the first structured teaching effort aiming to offer surgeons a full immersion in RAKT to train the core technical skills.

Production of OSU G5P[7] Porcine Rotavirus Expressing a Fluorescent Reporter via Reverse Genetics.

Rotaviruses are a significant cause of severe, potentially life-threatening gastroenteritis in infants and the young of many economically important animals. Although vaccines against porcine rotavirus exist, both live oral and inactivated, their effectiveness in preventing gastroenteritis is less than ideal. Thus, there is a need for the development of new generations of porcine rotavirus vaccines. The Ohio State University (OSU) rotavirus strain represents a Rotavirus A species with a G5P[7] genotype, the genotype most frequently associated with rotavirus disease in piglets. Using complete genome sequences that were determined via Nanopore sequencing, we developed a robust reverse genetics system enabling the recovery of recombinant (r)OSU rotavirus. Although rOSU grew to high titers (~107 plaque-forming units/mL), its growth kinetics were modestly decreased in comparison to the laboratory-adapted OSU virus. The reverse genetics system was used to generate the rOSU rotavirus, which served as an expression vector for a foreign protein. Specifically, by engineering a fused NSP3-2A-UnaG open reading frame into the segment 7 RNA, we produced a genetically stable rOSU virus that expressed the fluorescent UnaG protein as a functional separate product. Together, these findings raise the possibility of producing improved live oral porcine rotavirus vaccines through reverse-genetics-based modification or combination porcine rotavirus vaccines that can express neutralizing antigens for other porcine enteric diseases.

Silver carboxylate-TiO2/polydimethyl siloxane is a safe and effective antimicrobial with significant wound care potential.

With the rise in antibiotic resistance, new methodologies are needed to combat musculoskeletal infections. Silver is an antimicrobial that can be synthesized in different forms, but its pharmacokinetics are difficult to control. This study details the antibacterial efficacy and cellular cytotoxicity of a formulation consisting of silver carboxylate (AgCar) released through a titanium dioxide/polydimethylsiloxane matrix with a predictable release profile on Pseudomonas aeruginosa, Acinetobacterium baumannii, and human-derived primary osteoblasts. Through an Institutional Animal Care and Use Committee and IRB-approved protocol, AgCar was applied to live Yucatan porcine skin and histologically analyzed for skin penetration. Graphite Furnace Atomic Absorption Spectroscopy (GFAAS) was used to measure elution of AgCar. Dose-response curves were generated through optical density to assess potency. Finally, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to quantify the cellular cytotoxicity of the novel formulation. The results were subject to statistical analysis using analysis of variance and post hoc Tukey tests. The silver carboxylate coating demonstrated deep penetration into the epithelium at the level of the deep pilosebaceous glands in animal models. GFAAS testing demonstrated the extended elution profile of silver carboxylate over 96 hours, while 100% silver with no titanium dioxide-polydimethylsiloxane matrix fully eluted within 48 hours. 10x silver carboxylate demonstrated superior antimicrobial activity to antibiotics and other silver formulations and showed minimal cytotoxicity compared with other silver formulations. Current antimicrobial therapies in wound care and surgical antisepsis, such as chlorhexidine gluconate, have pitfalls including poor skin penetration and short duration of efficacy. The broad antimicrobial activity, extended elution, and deep skin penetration of this AgCar formulation show great promise for surgical site infection and wound care treatment. Novel technology to fight the growing threat of microbial resistance should be at the forefront of orthopaedic surgical site infection prevention and treatment.

Perforator Dissection Porcine Abdominal Model: A Novel Simulator to Improve Microsurgical Training.

Perforator dissection and flap elevation are routinely performed for microsurgical reconstruction; however, there is a steep learning curve to mastering these technical skills. Though live porcine models have been utilized as microsurgical training models, significant drawbacks limit their use. We recently developed a latex-perfused, nonliving, porcine abdomen perforator dissection simulation and described its anatomic similarity to the human deep inferior epigastric artery flap. The purpose was to assess the change in resident confidence in performing key operative steps of flap elevation and perforator dissection and obtain feedback on model realism and utility. Seventeen plastic and reconstructive surgery resident physicians (postgraduate years 1-6) at a single institution participated in a perforator dissection session utilizing the simulation model. Each resident completed pre- and postactivity surveys to assess interval change in confidence in operating. The postactivity survey also asked residents to answer questions regarding their perception of the model's anatomic and surgical realism and utility in microsurgical training. Following a practice session using the latex-perfused, nonliving porcine abdomen, resident confidence was significantly increased in performing all key operative steps and the procedure overall (p = 0.001). All residents (n = 17, 100%) believed the model would improve "trainees' ability to perform perforator dissection in the operating room." Perforator, fascial, and pedicle anatomy were reported to be "Very" similar to human anatomy, with a median Likert score (MLS) of 4. Additionally, six out of the eight surgical steps were noted to be "Very" realistic, with only "Flap Design" and "Fascial Closure" found to be "Moderately" realistic with an MLS of 3. The latex-infused porcine abdominal model is a novel, realistic simulation for microsurgical trainee perforator dissection practice. This model offers a suitable substitute for perforator dissection practice, as its implementation within a microsurgery training course improves resident comfort and confidence.

Learning curve of ultrasound-guided surgeon-administered transversus abdominis plane (UGSA-TAP) block on a porcine model

BackgroundSurgeons commonly perform ultrasound-guided Transversus Abdominis Plane blocks to manage acute pain following abdominal surgeries. There is no consensus on whether surgeons should undergo basic hands-on training to perform TAP blocks or if video-based learning is sufficient. We theorized that simulation-based learning is superior to video-based learning. In the present study, we present the analysis of technical skills of UGSA-TAP block performance on a live porcine model by general surgery trainees after undergoing video or simulation-based learning. MethodsWe performed a prospective, double-blinded, randomized study. Ten surgery residents and two surgery critical-care fellows (n = 12) without prior experience in performing the TAP block were recruited. The participants were randomized either into a video-based or simulation-based training group. After that, all participants performed a TAP block on a live anesthetized pig, which was recorded and scored by three blinded anesthesiologists. All participants completed a post-performance survey to assess their confidence in gaining competency in the UGSA-TAP block. Statistical analyses were performed to assess the differences between the two groups. P < 0.05 was considered statistically significant. ResultsAll simulation-based learning participants successfully performed a survey scan, identified the three muscular layers of the abdominal wall, and identified the transversus abdominis plane compared to 50 %, 50 %, and 33 % video-based learning group participants for the respective parameters (p < 0.05). While some performance metrics showed no statistically significant differences between the groups, substantial effect sizes (Cohen's ℎ up to 1.07) highlighted notable differences in participants' performance. Both groups exhibited confidence in core competencies, with varied rates of satisfactory skill execution. Performance assessed using a global rating scale revealed a higher passing rate for the simulation group (83 % vs. 33 %). Participant feedback via the Likert scale reflected confidence post-training. Inter-rater reliability (0.83–1) confirmed the robustness of study evaluations. ConclusionThe UGSA-TAP block curriculum should be introduced into the surgical residency programs with an emphasis on simulation-based learning to enhance the procedural skills of the trainees before transitioning to surgical patients.

IDEAL-D Phase 0 Evaluation of the Avatera System in Robot-Assisted Prostate, Bladder and Renal Surgery.

Purpose: To evaluate the utilization of novel Avatera system in urological operations according to the IDEAL-D framework recommendations for high-risk invasive surgical devices. Materials and Methods: Three surgeons attempted to perform 23 upper and lower urinary tract operations on human cadavers and in live porcine models using the Avatera system. Total operative time and the duration of the substeps were evaluated. Surgical performance was assessed with the Global Evaluative Assessment of Robotic Skills (GEARS) score. Suturing was rated using the technical checklist for the assessment of suturing in robotic surgery. Attending surgeons rated their satisfaction with the Avatera system on a scale of 1-5. Results and Limitation: Seventeen out of 18 operations performed on cadavers were completed, while one pyeloplasty was discontinued. All five operations performed in porcine models were completed. Although 1 pig was euthanized on the fifth postoperative day, its symptoms were unrelated to surgery. Mean GEARS and Suturing scores in the upper urinary tract were 29 ± 0.7 and 29.5 ± 0.95, respectively, and in the lower urinary 28.5 ± 1.2 and 29.5 ± 0.5, respectively. Surgeons' satisfaction was high or very high for all procedures. Conclusions: The Avatera system was associated with good surgical performance and high surgeons' satisfaction rates. All urological procedures performed were shown to be feasible, with comparable risks to other robot-assisted surgery systems.

Intraoperative liver deformation and organ motion caused by ventilation, laparotomy, and pneumoperitoneum in a porcine model for image-guided liver surgery

BackgroundImage-guidance promises to make complex situations in liver interventions safer. Clinical success is limited by intraoperative organ motion due to ventilation and surgical manipulation. The aim was to assess influence of different ventilatory and operative states on liver motion in an experimental model.MethodsLiver motion due to ventilation (expiration, middle, and full inspiration) and operative state (native, laparotomy, and pneumoperitoneum) was assessed in a live porcine model (n = 10). Computed tomography (CT)-scans were taken for each pig for each possible combination of factors. Liver motion was measured by the vectors between predefined landmarks along the hepatic vein tree between CT scans after image segmentation.ResultsLiver position changed significantly with ventilation. Peripheral regions of the liver showed significantly higher motion (maximal Euclidean motion 17.9 ± 2.7 mm) than central regions (maximal Euclidean motion 12.6 ± 2.1 mm, p < 0.001) across all operative states. The total average motion measured 11.6 ± 0.7 mm (p < 0.001). Between the operative states, the position of the liver changed the most from native state to pneumoperitoneum (14.6 ± 0.9 mm, p < 0.001). From native state to laparotomy comparatively, the displacement averaged 9.8 ± 1.2 mm (p < 0.001). With pneumoperitoneum, the breath-dependent liver motion was significantly reduced when compared to other modalities. Liver motion due to ventilation was 7.7 ± 0.6 mm during pneumoperitoneum, 13.9 ± 1.1 mm with laparotomy, and 13.5 ± 1.4 mm in the native state (p < 0.001 in all cases).ConclusionsVentilation and application of pneumoperitoneum caused significant changes in liver position. Liver motion was reduced but clearly measurable during pneumoperitoneum. Intraoperative guidance/navigation systems should therefore account for ventilation and intraoperative changes of liver position and peripheral deformation.

Transendoscopic flexible parallel continuum robotic mechanism for bimanual endoscopic submucosal dissection

In endoscopic submucosal dissection (ESD), the gastrointestinal (GI) tract warrants the surgical instruments to navigate through a long, narrow and tortuous endoscope. This poses a great challenge in developing ESD instruments with small dimensions, flexibility, and high distal dexterity. In this work, we propose the first Transendoscopic Flexible Parallel Continuum Robotic mechanism to develop a miniature dexterous flexible-stiff-balanced Wrist (FPCW). Besides, it can steer multifunctional instruments of diameters 2.5 mm to 3.5 mm, including the electrosurgical knife, injection needle, and forceps. Our FPCW instruments are adaptable to commercially available dual-channel endoscopes (diameter: <12 mm, channel width: 2.8 mm and around 3.8 mm). Furthermore, we develop a surgical telerobotic system, called DREAMS (Dual-arm Robotic Endoscopic Assistant for Minimally Invasive Surgery), by using our smallest FPCW instruments for bimanual ESD procedures. First, we conduct a series of experiments to determine the FPCW’s design and kinematics parameters and to verify the mechanical properties of the FPCW instruments’ prototypes, including workspace, stiffness, strength, and teleoperation accuracy. Second, we validate the functionality of the FPCW instruments through ex-vivo tests by performing ESD steps on porcine stomachs. Finally, we perform an invivo test on a live porcine model and showcase that our developed DREAMS can be teleoperated intuitively to perform bimanual ESD efficiently with an average dissection speed of 108.95 mm2/min at the greater curvature in gastric body, which demonstrates that our DREAMS has satisfactory maneuverability as well as accuracy and is more competitive than counterpart robotic systems.

Delivering wireless ultrasound energy to remote systems: Design implications for powering medical implants requiring milliwatt versus several watts of power

Current medical device technological advances either involve, miniaturization or wireless operation or both. Miniaturization enables implant placement closer to target organs, e.g., blood vessels, viscera, or neurological structures, while wireless powering of larger left-ventricular assist devices (LVAD) is desired to mitigate infection risk due to wires. Ultrasound is a viable energy modality, wirelessly propagating through material media (tissue) and either directly powers systems, or charges an integrated battery. Whether powering implantables, or non-implantable systems, such as digital devices, ultrasound power transfer approaches have to be application-specific. This talk will present data and development strategies for four distinct use-cases requiring respectively, &amp;lt;5 mW (miniaturized systems), ∼500 mW (implantable pulse generators, IPG), ∼2 W (non-implanted digital systems), and ∼8 W (LVADs). Choice of low-MHz frequency, planar single-element or coarse array transmit sources, as well as application-dependent receivers a few wavelengths in size (low-mW), to 45 mm diameter (∼8 W), will be described. Benchtop experiments demonstrate successful ultrasound charging of a miniaturized solid-state (250 mAh) battery within 20 minutes. Results from live porcine model studies show a 200 mAh Li-ion battery within a Ti-shelled IPG, being successfully charged without thermal-effect-related tissue changes in the propagation path. [Work partially supported by NIH/NIBIB R43EB019225.]

A Role for Live-Animal Models in Undergraduate Surgical Education During the Cadaver Shortage.

A Role for Live-Animal Models in Undergraduate Surgical Education During the Cadaver Shortage.

Design and Testing of a Superelastic Nitinol Tissue Attachment Mechanism for Long-Term Gastrointestinal Device Retention

AbstractIngestible devices have become a popular means for diagnosing and treating the gastrointestinal (GI) tract due to their noninvasive nature. However, their residency period in the GI tract is limited by the transit time through it. In previous work, we designed a tissue attachment mechanism (TAM) inspired by parasitic worms' attachment methods, which were tested for implanting biosensors or drug delivery payloads to the small intestine with a swallowable capsule robot. In that work, the attachment success rate was 91.7%, and the average attachment duration of the TAM was 32.2 h after factorial optimization of major design factors. This work develops a novel nitinol TAM (NTAM) for improving the attachment duration using the shape-changing properties of nitinol. The attachment strength of the NTAM to the intestinal tissue was assessed both ex vivo and in vivo. The attachment duration of the NTAMs in live porcine models was evaluated from radiographic images, and histological analysis of the attachment location of an NTAM was performed after euthanasia. The NTAM was 100% successful in an attachment strength study and achieved a maximum attachment duration of 13 days, while the average attachment duration was 85.63 ± 77.83 h. Histological analysis did not report any permanent damage to the tissue. This work shows a 2.7-fold improvement in attachment duration over the previous design. This work has demonstrated a method of prolonged attachment to the intestinal wall through a swallowable device, which can be used for long-term drug delivery or biosensing.