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D'Angelo DC, Stephens SE, Jensen MO, Thomas LR. Design, fabrication, and evaluation of 3-D-printed cystotomy spoons as a retrieval method in dogs. Am J Vet Res 2023; 84:1-8. [PMID: 37507119 DOI: 10.2460/ajvr.23.02.0038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 07/12/2023] [Indexed: 07/30/2023]
Abstract
OBJECTIVE Current cystotomy methods often implement the use of off-label devices, resulting in urocystolith extraction difficulty and potentially leading to postoperative complications and discomfort for the patient. The objective of this study was to create 3 novel 3-D printed cystotomy spoons that offer a dedicated solution for removing urocystoliths from a patient's urinary bladder. ANIMALS Clinical use of the 3 novel 3-D printed cystotomy spoons were ultimately evaluated in 4 dogs and 1 cat that presented for urocystotlith removal at 3 different veterinary hospitals in northwest Arkansas. METHODS The novel cystotomy spoons were designed using SolidWorks, 3-D printed with a Dental Surgical Guide resin, and underwent prototype testing that included chlorhexidine soaking, autoclave sterilization, 3-point bend testing, and Finite Element Analysis. The efficiency of the spoons was then evaluated through a limited proof-of-concept study utilizing a postoperative questionnaire for the participating clinicians. RESULTS Practitioner feedback indicated positive experiences using 1 or more of the novel 3-D printed cystotomy spoons while performing a cystotomy surgery. However, successful use of the spoons was ultimately limited to dogs in the 23 to 34 kg weight range. CLINICAL RELEVANCE Novel 3-D printed cystotomy spoons have the potential to mediate urocystolith extraction difficulty and reduce postoperative complications. Additionally, this research demonstrates how veterinarians might develop custom 3-D models and prints to meet patient-specific needs. As such, further development could impact the standard of healthcare and the veterinary industry by promoting the use of additive manufacturing in veterinary medicine.
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Affiliation(s)
- Davina C D'Angelo
- Department of Animal Sciences, Dale Bumpers College of Agricultural, Food and Life Sciences, University of Arkansas, Fayetteville, AR
| | - Sam E Stephens
- Department of Biomedical Engineering, College of Engineering, University of Arkansas, Fayetteville, AR
| | - Morten O Jensen
- Department of Biomedical Engineering, College of Engineering, University of Arkansas, Fayetteville, AR
- Department of Surgery, University of Arkansas for Medical Sciences, Little Rock, AR
| | - Lauren R Thomas
- Department of Animal Sciences, Dale Bumpers College of Agricultural, Food and Life Sciences, University of Arkansas, Fayetteville, AR
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Crimmins-Pierce LD, Bonvillain GP, Henry KR, Hayat MA, Villafranca AA, Stephens SE, Jensen HK, Sanford JA, Wu J, Sexton KW, Jensen MO. Critical Information from High Fidelity Arterial and Venous Pressure Waveforms During Anesthesia and Hemorrhage. Cardiovasc Eng Technol 2022; 13:886-898. [PMID: 35545752 DOI: 10.1007/s13239-022-00624-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 04/08/2022] [Indexed: 01/27/2023]
Abstract
PURPOSE Peripheral venous pressure (PVP) waveform analysis is a novel, minimally invasive, and inexpensive method of measuring intravascular volume changes. A porcine cohort was studied to determine how venous and arterial pressure waveforms change due to inhaled and infused anesthetics and acute hemorrhage. METHODS Venous and arterial pressure waveforms were continuously collected, while each pig was under general anesthesia, by inserting Millar catheters into a neighboring peripheral artery and vein. The anesthetic was varied from inhaled to infused, then the pig underwent a controlled hemorrhage. Pearson correlation coefficients between the power of the venous and arterial pressure waveforms at each pig's heart rate frequency were calculated for each variation in the anesthetic, as well as before and after hemorrhage. An analysis of variance (ANOVA) test was computed to determine the significance in changes of the venous pressure waveform means caused by each variation. RESULTS The Pearson correlation coefficients between venous and arterial waveforms decreased as anesthetic dosage increased. In an opposing fashion, the correlation coefficients increased as hemorrhage occurred. CONCLUSION Anesthetics and hemorrhage alter venous pressure waveforms in distinctly different ways, making it critical for researchers and clinicians to consider these confounding variables when utilizing pressure waveforms. Further work needs to be done to determine how best to integrate PVP waveforms into clinical decision-making.
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Affiliation(s)
| | - Gabriel P Bonvillain
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR, USA
| | - Kaylee R Henry
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR, USA
| | - Md Abul Hayat
- Department of Electrical Engineering, University of Arkansas, Fayetteville, AR, USA
| | - Adria Abella Villafranca
- Department of Biomedical Informatics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Sam E Stephens
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR, USA
| | - Hanna K Jensen
- Department of Surgery, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Joseph A Sanford
- Department of Anesthesiology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
- Department of Biomedical Informatics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
- Institute for Digital Health and Innovation, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Jingxian Wu
- Department of Electrical Engineering, University of Arkansas, Fayetteville, AR, USA
| | - Kevin W Sexton
- Department of Surgery, University of Arkansas for Medical Sciences, Little Rock, AR, USA
- Department of Biomedical Informatics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
- Institute for Digital Health and Innovation, University of Arkansas for Medical Sciences, Little Rock, AR, USA
- Department of Health Policy and Management, University of Arkansas for Medical Sciences, Little Rock, AR, USA
- Department of Pharmacy Practice, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Morten O Jensen
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR, USA.
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Wood K, Stephens SE, Xu F, Hazaa A, Meek JC, Jensen HK, Jensen MO, Wickramasinghe R. In Vitro Blood Clot Formation and Dissolution for Testing New Stroke-Treatment Devices. Biomedicines 2022; 10:biomedicines10081870. [PMID: 36009417 PMCID: PMC9405282 DOI: 10.3390/biomedicines10081870] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 07/18/2022] [Accepted: 07/23/2022] [Indexed: 12/30/2022] Open
Abstract
Strokes are among the leading causes of death worldwide. Ischemic stroke, due to plaque or other buildup blocking blood flow to the brain, is the most common type. Although ischemic stroke is treatable, current methods have severe shortcomings with high mortality rates. Clot retrieval devices, for example, can result in physically damaged vessels and death. This study aims to create blood clots that are representative of those found in vivo and demonstrate a new method of removing them. Static blood clots were formed using a 9:1 ratio of whole sheep blood and 2.45% calcium chloride solution. This mixture was heated in a water bath at 37 °C for approximately one hour until solidified. Following clot solidification, human plasmin was introduced by various methods, including soaking, injection, and membrane perfusion, and the resulting dissolution percentages were determined. Different clot types, representative of the wide range found physiologically, were also manufactured and their dissolution characteristics evaluated. A method to reproducibly create blood clots, characteristic of those found in vivo, is essential for the production of stroke retrieval devices that can efficiently and effectively remove clots from patients with low mortality rates and little/no damage to the surrounding vessels.
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Affiliation(s)
- Kayla Wood
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR 72701, USA; (K.W.); (S.E.S.); (F.X.); (A.H.)
| | - Sam E. Stephens
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR 72701, USA; (K.W.); (S.E.S.); (F.X.); (A.H.)
| | - Feng Xu
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR 72701, USA; (K.W.); (S.E.S.); (F.X.); (A.H.)
| | - Alshaimaa Hazaa
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR 72701, USA; (K.W.); (S.E.S.); (F.X.); (A.H.)
| | - James C. Meek
- Interventional Radiology Clinic, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA;
| | - Hanna K. Jensen
- Departments of Radiology and Surgery, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA;
| | - Morten O. Jensen
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR 72701, USA; (K.W.); (S.E.S.); (F.X.); (A.H.)
- Correspondence: (M.O.J.); (R.W.); Tel.: +1-479-575-4216 (M.O.J.); +1-479-575-8475 (R.W.)
| | - Ranil Wickramasinghe
- Ralph E Martin Department of Chemical Engineering, University of Arkansas, Fayetteville, AR 72701, USA
- Correspondence: (M.O.J.); (R.W.); Tel.: +1-479-575-4216 (M.O.J.); +1-479-575-8475 (R.W.)
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Elmer KM, Bean MJ, Uretsky BF, Stephens SE, Jensen HK, Jensen MO. Customizable Angioplasty Balloon-Forming Machine: Towards Precision Medicine in Coronary Bifurcation Lesion Interventions. J Cardiovasc Transl Res 2022; 15:1119-1128. [PMID: 35312960 DOI: 10.1007/s12265-022-10229-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 02/25/2022] [Indexed: 10/18/2022]
Abstract
The ability to customize the size and shape of angioplasty balloons may be useful in many clinical and research applications of coronary and endovascular intervention. Fully customizable balloons are outside the reach of most researchers due to their prohibitive cost. A small-scale balloon-forming machine was developed to produce fully customizable balloons. This study describes the creation of this customizable balloon-forming machine and identifies the key components of manufacturing a patient-specific balloon. Using a standard balloon-shaped mold created with a novel application of 3D stereolithography-printed resin, 104 PET balloon formation tests were conducted. A statistical study was conducted in which molding temperature and inflation air pressure were independent variables ranging from 100 to 130 °C and from 3.7 to 6.8 atm, respectively. The criteria for balloon-forming success were defined; pressure and temperature combined were found to have a significant impact on the success (p = 0.011), with 120 °C and 4.76 atm resulting in the highest chance for success based on a regression model.
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Affiliation(s)
- Kaitlyn M Elmer
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR, USA
| | - Maxwell J Bean
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR, USA
| | - Barry F Uretsky
- Department of Internal Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Sam E Stephens
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR, USA
| | - Hanna K Jensen
- Departments of Surgery and Radiology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Morten O Jensen
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR, USA.
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Stephens SE, Kammien AJ, Paris JC, Applequist AP, Ingels NB, Jensen HK, Rodgers DE, Cole CR, Wenk JF, Jensen MO. In Vitro Mitral Valve Model with Unrestricted Ventricular Access: Using Vacuum to Close the Valve and Enable Static Trans-Mitral Pressure. J Cardiovasc Transl Res 2022; 15:845-854. [PMID: 34993757 PMCID: PMC9256857 DOI: 10.1007/s12265-021-10199-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 12/13/2021] [Indexed: 11/27/2022]
Abstract
Current in vitro models of the left heart establish the pressure difference required to close the mitral valve by sealing and pressurizing the ventricular side of the valve, limiting important access to the subvalvular apparatus. This paper describes and evaluates a system that establishes physiological pressure differences across the valve using vacuum on the atrial side. The subvalvular apparatus is open to atmospheric pressure and accessible by tools and sensors, establishing a novel technique for experimentation on atrioventricular valves. Porcine mitral valves were excised and closed by vacuum within the atrial chamber. Images were used to document and analyze closure of the leaflets. Papillary muscle force and regurgitant flow rate were measured to be 4.07 N at 120 mmHg and approximately 12.1 ml/s respectively, both of which are within clinically relevant ranges. The relative ease of these measurements demonstrates the usefulness of improved ventricular access at peak pressure/force closure.
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Affiliation(s)
- Sam E Stephens
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR, USA
| | - Alexander J Kammien
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR, USA
| | - Jacob C Paris
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR, USA
| | - Alexis P Applequist
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR, USA
| | - Neil B Ingels
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR, USA
| | - Hanna K Jensen
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR, USA.,Department of Surgery, University of Arkansas for Medical Sciences, Fayetteville, AR, USA
| | - Drew E Rodgers
- Department of Anesthesiology, Washington Regional Medical Center, Fayetteville, AR, USA
| | - Charles R Cole
- Department of Cardiovascular Surgery, Washington Regional Medical Center, Fayetteville, AR, USA
| | - Jonathan F Wenk
- Department of Mechanical Engineering, University of Kentucky, Lexington, KY, USA
| | - Morten O Jensen
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, AR, USA.
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Stephens SE, Liachenko S, Ingels NB, Wenk JF, Jensen MO. High resolution imaging of the mitral valve in the natural state with 7 Tesla MRI. PLoS One 2017; 12:e0184042. [PMID: 28854273 PMCID: PMC5576658 DOI: 10.1371/journal.pone.0184042] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Accepted: 08/16/2017] [Indexed: 11/20/2022] Open
Abstract
Imaging techniques of the mitral valve have improved tremendously during the last decade, but challenges persist. The delicate changes in annulus shape and papillary muscle position throughout the cardiac cycle have significant impact on the stress distribution in the leaflets and chords, thus preservation of anatomically accurate positioning is critical. The aim of this study was to develop an in vitro method and apparatus for obtaining high-resolution 3D MRI images of porcine mitral valves in both the diastolic and systolic configurations with physiologically appropriate annular shape, papillary muscle positions and orientations, specific to the heart from which the valve was harvested. Positioning and mounting was achieved through novel, customized mounting hardware consisting of papillary muscle and annulus holders with geometries determined via pre-mortem ultrasonic intra-valve measurements. A semi-automatic process was developed and employed to tailor Computer Aided Design models of the holders used to mount the valve. All valve mounting hardware was 3D printed using a stereolithographic printer, and the material of all fasteners used were brass for MRI compatibility. The mounted valves were placed within a clear acrylic case, capable of holding a zero-pressure and pressurized liquid bath of a MRI-compatible fluid. Obtaining images from the valve submerged in liquid fluid mimics the natural environment surrounding the valve, avoiding artefacts due to tissue surface tension mismatch and gravitational impact on tissue shape when not neutrally buoyant. Fluid pressure was supplied by reservoirs held at differing elevations and monitored and controlled to within ±1mmHg to ensure that the valves remained steady. The valves were scanned in a 7 Tesla MRI system providing a voxel resolution of at least 80μm. The systematic approach produced 3D datasets of high quality which, when combined with physiologically accurate positioning by the apparatus, can serve as an important input for validated computational models.
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Affiliation(s)
- Sam E. Stephens
- Department of Mechanical Engineering, University of Arkansas, Fayetteville, Arkansas, United States of America
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, Arkansas, United States of America
| | - Serguei Liachenko
- Division of Neurotoxicology, National Center for Toxicological Research, US Food and Drug Administration, Jefferson, Arkansas, United States of America
| | - Neil B. Ingels
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, Arkansas, United States of America
| | - Jonathan F. Wenk
- Department of Mechanical Engineering, University of Kentucky, Lexington, Kentucky, United States of America
| | - Morten O. Jensen
- Department of Biomedical Engineering, University of Arkansas, Fayetteville, Arkansas, United States of America
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Stephens SE, Rigden SPA. Cystic fibrosis and renal disease. Paediatr Respir Rev 2002; 3:135-8. [PMID: 12297060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/05/2023]
Abstract
Renal disease is relatively rare in cystic fibrosis even though the cystic fibrosis transmembrane regulator (CFTR) protein is expressed in abundance in the kidney. Aberrant CFTR expression probably explains the subtle abnormalities in renal concentrating and diluting ability described in cystic fibrosis and possibly the increased incidence of nephrocalcinosis. It also provides a hypothesis for the important differences in renal handling of some drugs. As the prognosis improves for patients with cystic fibrosis, secondary renal complications, for example glomerulonephritis and amyloidosis, are likely to become more prevalent. There are also a number of potentially nephrotoxic drugs used in the management of cystic fibrosis.
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Affiliation(s)
- S E Stephens
- Nephro-urology Department, Institute of Child Health, 30, Guildford Street, London WC1 1EH, UK
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Stephens SE, Rigden SPA. Case 5: assessment. Allergic tubular interstitial nephritis. Paediatr Respir Rev 2002; 3:162, 165-6. [PMID: 12465605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
Affiliation(s)
- S E Stephens
- Nephro-Urology Department, Institute of Child Health, London, UK
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Hale S, Stephens SE. Neurological treatments. Physiotherapy 1983; 69:72-5. [PMID: 6611713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Cornwell-Jones CA, Stephens SE, Dunston GA. Early odor preference of rats are preserved by neonatal 6-hydroxydopamine. Behav Neural Biol 1982; 35:217-30. [PMID: 6817744 DOI: 10.1016/s0163-1047(82)90653-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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