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Elisha G, Halder S, Carlson DA, Kou W, Kahrilas PJ, Pandolfino JE, Patankar NA. A Mechanics-Based Perspective on the Function of Human Sphincters During Functional Luminal Imaging Probe Manometry. J Biomech Eng 2024; 146:021001. [PMID: 37994843 PMCID: PMC10750791 DOI: 10.1115/1.4064125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 11/17/2023] [Accepted: 11/17/2023] [Indexed: 11/24/2023]
Abstract
Functional luminal imaging probe (FLIP) is used to measure cross-sectional area (CSA) and pressure at sphincters. It consists of a catheter surrounded by a fluid filled cylindrical bag, closed on both ends. Plotting the pressure-CSA hysteresis of a sphincter during a contraction cycle, which is available through FLIP testing, offers information on its functionality, and can provide diagnostic insights. However, limited work has been done to explain the mechanics of these pressure-CSA loops. This work presents a consolidated picture of pressure-CSA loops of different sphincters. Clinical data reveal that although sphincters have a similar purpose (controlling the flow of liquids and solids by opening and closing), two different pressure-CSA loop patterns emerge: negative slope loop (NSL) and positive slope loop (PSL). We show that the loop type is the result of an interplay between (or lack thereof) two mechanical modes: (i) neurogenic mediated relaxation of the sphincter muscle or pulling applied by external forces, and (ii) muscle contraction proximal to the sphincter which causes mechanical distention. We conclude that sphincters which only function through mechanism (i) exhibition NSL whereas sphincters which open as a result of both (i) and (ii) display a PSL. This work provides a fundamental mechanical understanding of human sphincters. This can be used to identify normal and abnormal phenotypes for the different sphincters and help in creating physiomarkers based on work calculation.
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Affiliation(s)
- Guy Elisha
- Department of Mechanical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL 60201
| | - Sourav Halder
- Theoretical and Applied Mechanics Program, McCormick School of Engineering, Northwestern University, Evanston, IL 60201
| | - Dustin A. Carlson
- Division of Gastroenterology and Hepatology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Wenjun Kou
- Division of Gastroenterology and Hepatology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Peter J. Kahrilas
- Division of Gastroenterology and Hepatology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - John E. Pandolfino
- Division of Gastroenterology and Hepatology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Neelesh A. Patankar
- Department of Mechanical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL 60201; Theoretical and Applied Mechanics Program, McCormick School of Engineering, Northwestern University, Evanston, IL 60201
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Drake CE, Cheng LK, Paskaranandavadivel N, Alighaleh S, Angeli-Gordon TR, Du P, Bradshaw LA, Avci R. Stomach Geometry Reconstruction Using Serosal Transmitting Coils and Magnetic Source Localization. IEEE Trans Biomed Eng 2023; 70:1036-1044. [PMID: 36121949 PMCID: PMC10069741 DOI: 10.1109/tbme.2022.3207770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE Bioelectric slow waves (SWs) are a key regulator of gastrointestinal motility, and disordered SW activity has been linked to motility disorders. There is currently a lack of practical options for the acquisition of the 3D stomach geometry during research studies when medical imaging is challenging. Accurately recording the geometry of the stomach and co-registering electrode and sensor positions would provide context for in-vivo studies and aid the development of non-invasive methods of gastric SW assessment. METHODS A stomach geometry reconstruction method based on the localization of transmitting coils placed on the gastric serosa was developed. The positions and orientations of the coils, which represented boundary points and surface-normal vectors, were estimated using a magnetic source localization algorithm. Coil localization results were then used to generate surface models. The reconstruction method was evaluated against four 3D-printed anatomically realistic human stomach models and applied in a proof of concept in-vivo pig study. RESULTS Over ten repeated reconstructions, average Hausdorff distance and average surface-normal vector error values were 4.7 ±0.2 mm and 18.7 ±0.7° for the whole stomach, and 3.6 ±0.2 mm and 14.6 ±0.6° for the corpus. Furthermore, mean intra-array localization error was 1.4 ±1.1 mm for the benchtop experiment and 1.7 ±1.6 mm in-vivo. CONCLUSION AND SIGNIFICANCE Results demonstrated that the proposed reconstruction method is accurate and feasible. The stomach models generated by this method, when co-registered with electrode and sensor positions, could enable the investigation and validation of novel inverse analysis techniques.
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Elisha G, Halder S, Acharya S, Carlson DA, Kou W, Kahrilas PJ, Pandolfino JE, Patankar NA. A mechanics-based perspective on the function of the esophagogastric junction during functional luminal imaging probe manometry. Biomech Model Mechanobiol 2023; 22:905-923. [PMID: 36752983 DOI: 10.1007/s10237-023-01688-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Accepted: 01/05/2023] [Indexed: 02/09/2023]
Abstract
The esophagogastric junction (EGJ) is located at the distal end of the esophagus and acts as a valve allowing swallowed food to enter the stomach and preventing acid reflux. Irregular weakening or stiffening of the EGJ muscles results in changes to its opening and closing patterns which can progress into esophageal disorders. Therefore, understanding the physics of the opening and closing cycle of the EGJ can provide mechanistic insights into its function and can help identify the underlying conditions that cause its dysfunction. Using clinical functional lumen imaging probe (FLIP) data, we plotted the pressure-cross-sectional area loops at the EGJ location and distinguished two major loop types-a pressure dominant loop and a tone dominant loop. In this study, we aimed to identify the key characteristics that define each loop type and determine what causes the inversion from one loop to another. To do so, the clinical observations are reproduced using 1D simulations of flow inside a FLIP device located in the esophagus, and the work done by the EGJ wall over time is calculated. This work is decomposed into active and passive components, which reveal the competing mechanisms that dictate the loop type. These mechanisms are esophageal stiffness, fluid viscosity, and the EGJ relaxation pattern.
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Affiliation(s)
- Guy Elisha
- Department of Mechanical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL, USA
| | - Sourav Halder
- Theoretical and Applied Mechanics Program, McCormick School of Engineering, Northwestern University, Evanston, IL, USA
| | - Shashank Acharya
- Department of Mechanical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL, USA
| | - Dustin A Carlson
- Division of Gastroenterology and Hepatology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Wenjun Kou
- Division of Gastroenterology and Hepatology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Peter J Kahrilas
- Division of Gastroenterology and Hepatology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - John E Pandolfino
- Division of Gastroenterology and Hepatology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Neelesh A Patankar
- Department of Mechanical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL, USA. .,Theoretical and Applied Mechanics Program, McCormick School of Engineering, Northwestern University, Evanston, IL, USA.
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Elisha G, Halder S, Carlson DA, Kahrilas PJ, Pandolfino JE, Patankar NA. A mechanics-based perspective on the pressure-cross-sectional area loop within the esophageal body. Front Physiol 2023; 13:1066351. [PMID: 36699676 PMCID: PMC9868904 DOI: 10.3389/fphys.2022.1066351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 12/12/2022] [Indexed: 01/12/2023] Open
Abstract
Introduction: Plotting the pressure-cross-sectional area (P-CSA) hysteresis loops within the esophagus during a contraction cycle can provide mechanistic insights into esophageal motor function. Pressure and cross-sectional area during secondary peristalsis can be obtained from the functional lumen imaging probe (FLIP). The pressure-cross-sectional area plots at a location within the esophageal body (but away from the sphincter) reveal a horizontal loop shape. The horizontal loop shape has phases that appear similar to those in cardiovascular analyses, whichinclude isometric and isotonic contractions followed by isometric and isotonic relaxations. The aim of this study is to explain the various phases of the pressurecross-sectional area hysteresis loops within the esophageal body. Materials and Methods: We simulate flow inside a FLIP device placed inside the esophagus lumen. We focus on three scenarios: long functional lumen imaging probe bag placed insidethe esophagus but not passing through the lower esophageal sphincter, long functional lumen imaging probe bag that crosses the lower esophageal sphincter, and a short functional lumen imaging probe bag placed in the esophagus body that does not pass through the lower esophageal sphincter. Results and Discussion: Horizontal P-CSA area loop pattern is robust and is reproduced in all three cases with only small differences. The results indicate that the horizontal loop pattern is primarily a product of mechanical conditions rather than any inherently different function of the muscle itself. Thus, the distinct phases of the loop can be explained solely based on mechanics.
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Affiliation(s)
- Guy Elisha
- Department of Mechanical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL, United States
| | - Sourav Halder
- Theoretical and Applied Mechanics Program, McCormick School of Engineering, Northwestern University, Evanston, IL, United States
| | - Dustin A. Carlson
- Division of Gastroenterology and Hepatology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Peter J. Kahrilas
- Division of Gastroenterology and Hepatology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - John E. Pandolfino
- Division of Gastroenterology and Hepatology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Neelesh A. Patankar
- Department of Mechanical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL, United States,Theoretical and Applied Mechanics Program, McCormick School of Engineering, Northwestern University, Evanston, IL, United States,*Correspondence: Neelesh A. Patankar,
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O'Connor A, Byrne CM, Vasant DH, Sharma A, Liao D, Klarskov N, Kiff ES, Telford K. Current and future perspectives on the utility of provocative tests of anal sphincter function: A state-of-the-art summary. Neurogastroenterol Motil 2022:e14496. [PMID: 36377815 DOI: 10.1111/nmo.14496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 10/18/2022] [Accepted: 11/01/2022] [Indexed: 11/16/2022]
Abstract
BACKGROUND The maintenance of fecal continence depends upon coordinated interactions between the pelvic floor, anorectum, and anal sphincter complex orchestrated by central and peripheral neural activities. The current techniques to objectively measure anorectal function rely on fixed diameter catheters placed inside the anal canal with a rectal balloon to obtain measurements of anal resting and squeeze function, and rectal compliance. Until recently it had not been possible to measure the distensibility of the anal canal, or in other words its ability to resist opening against an increasing pressure, which has been proposed as the main determinant of a biological sphincter's function. Anal acoustic reflectometry (AAR) and the functional lumen imaging probe (FLIP) are two novel, provocative techniques that dynamically assess the anal sphincter complex under volume-controlled distension. In doing so, both provide information on the viscoelastic properties of the anal canal and offer new insights into its function. PURPOSE This review details the current and potential future applications of AAR and FLIP and highlights the unanswered questions relevant to these new technologies.
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Affiliation(s)
- Alexander O'Connor
- Faculty of Biology, Medicine, and Health, The University of Manchester, Manchester, UK.,Department of Colorectal Surgery, Wythenshawe Hospital, Manchester University NHS Foundation Trust, Manchester, UK
| | - Caroline M Byrne
- Department of Colorectal Surgery, Wythenshawe Hospital, Manchester University NHS Foundation Trust, Manchester, UK
| | - Dipesh H Vasant
- Neurogastroenterology Unit, Gastroenterology, Wythenshawe Hospital, Manchester University NHS Foundation Trust, Manchester, UK.,Division of Diabetes, Endocrinology and Gastroenterology, The University of Manchester, Manchester, UK
| | - Abhiram Sharma
- Faculty of Biology, Medicine, and Health, The University of Manchester, Manchester, UK.,Department of Colorectal Surgery, Wythenshawe Hospital, Manchester University NHS Foundation Trust, Manchester, UK
| | - Donghua Liao
- Mech-Sense, Department of Gastroenterology and Hepatology, Aalborg University Hospital, Aalborg, Denmark
| | - Niels Klarskov
- Department of Obstetrics and Gynecology, Herlev University Hospital, Herlev, Denmark.,Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Edward S Kiff
- Department of Colorectal Surgery, Wythenshawe Hospital, Manchester University NHS Foundation Trust, Manchester, UK
| | - Karen Telford
- Faculty of Biology, Medicine, and Health, The University of Manchester, Manchester, UK.,Department of Colorectal Surgery, Wythenshawe Hospital, Manchester University NHS Foundation Trust, Manchester, UK
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Futaba K, Chen SC, Leung WW, Wong C, Mak T, Ng S, Gregersen H. Fecobionics characterization of female patients with fecal incontinence. Sci Rep 2022; 12:10602. [PMID: 35732729 PMCID: PMC9218093 DOI: 10.1038/s41598-022-14919-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Accepted: 06/15/2022] [Indexed: 12/12/2022] Open
Abstract
Defecatory disorders including fecal incontinence (FI) are diagnosed on the symptom pattern supplemented by anorectal manometry (ARM), the balloon expulsion test (BET), and endo-anal ultrasonography. In this study, we used a simulated stool named Fecobionics to study distinct defecation patterns in FI patients using preload-afterload diagrams and to provide comparative data on defecation indices (DIs) between passive and urge incontinent patients. All subjects had Fecobionics, endo-anal ultrasonography and ARM-BET done. The Fecobionics bag was distended in rectum until urge in 37 female patients (64.1 ± 1.5 yrs) and a group of normal subjects (NS, 12F, age 64.8 ± 2.8 yrs). Rear-front pressure (preload-afterload) diagrams and DIs were compared between groups. The FISI score in the patients was 8.6 ± 0.6. The NS did not report FI-related symptoms. All patients and NS defecated Fecobionics and ARM-BET within 2 min. The urge volume was 46.1 ± 3.6 and 35.3 ± 5.9 mL in the FI and normal groups (P > 0.1). The expulsion duration was 14.8 ± 2.4 and 19.8 ± 5.1 s for the two groups (P > 0.1). The preload-afterload diagrams demonstrated clockwise loops that clearly differed between the FI subtypes and NS. The DIs showed profound difference between patients and NS. Fecobionics data showed higher correlation with symptoms in FI patients than ARM-BET. Fecobionics obtained novel pressure signatures in subtypes of FI patients and NS. Fecobionics provides DI data that cannot be obtained with ARM-BET.
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Affiliation(s)
- Kaori Futaba
- Department of Surgery, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Ssu-Chi Chen
- Department of Surgery, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Wing Wa Leung
- Department of Surgery, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Cherry Wong
- Department of Surgery, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Tony Mak
- Department of Surgery, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Simon Ng
- Department of Surgery, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Hans Gregersen
- Department of Surgery, The Chinese University of Hong Kong, Shatin, Hong Kong.
- California Medical Innovations Institute, 11107 Roselle St., San Diego, CA, 92121, USA.
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Chen SC, Futaba K, Leung WW, Wong C, Mak T, Ng S, Gregersen H. Functional anorectal studies in patients with low anterior resection syndrome. Neurogastroenterol Motil 2022; 34:e14208. [PMID: 34145694 DOI: 10.1111/nmo.14208] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 05/24/2021] [Accepted: 06/01/2021] [Indexed: 12/23/2022]
Abstract
BACKGROUND Most patients who have undergone low anterior resection suffer from bowel dysfunction postoperatively. This condition is referred to as low anterior resection syndrome (LARS). The aim was to study defecatory patterns in LARS patients compared to a primary control group of fecal incontinence (FI) patients and normal subjects (NS) with the Fecobionics device. METHODS Fecobionics expulsion parameters were assessed in an interventional study design. The Fecobionics probe contained pressure sensors at the front, rear, and inside the bag. The bag was distended until urge sensation in rectum in 11 LARS patients (5F/6M, 63.2 ± 2.9 years), 11 FI subjects (7F/4M, 64.4 ± 2.5 years), and 11 NS (7F/4M, 63.6 ± 3.0 years). Defecation indices were computed from the Fecobionics data. All subjects had high-resolution anorectal manometry (ARM) and balloon expulsion test (BET) done. Symptoms were evaluated with LARS and Wexner scores. KEY RESULTS The LARS score in the LARS patients was 39.0 ± 0.6. The Wexner score in the LARS, FI, and NS groups was 14.2 ± 0.7, 10.1±1.0, and 0.0 ± 0.0 (p < 0.01). The resting anal pressure and squeeze pressure were lowest in LARS patients (p < 0.05). The urge volume was 11.8 ± 4.2, 59.6 ± 6.4, and 41.6 ± 6.4 ml in the LARS, FI, and NS groups, respectively (p < 0.001). The expulsion duration did not differ between groups. Defecation indices were lowest in the LARS patients (p < 0.05). ARM-BET confirmed the low urge volume in LARS patients whereas anal pressures did not differ between groups. CONCLUSIONS AND INFERENCES The LARS patients had low anal pressures and urge volume. Most Defecation Indices differed between the LARS group and the other groups.
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Affiliation(s)
- Ssu-Chi Chen
- Department of Surgery, the Chinese University of Hong Kong, Shatin, Hong Kong
| | - Kaori Futaba
- Department of Surgery, the Chinese University of Hong Kong, Shatin, Hong Kong
| | - Wing Wa Leung
- Department of Surgery, the Chinese University of Hong Kong, Shatin, Hong Kong
| | - Cherry Wong
- Department of Surgery, the Chinese University of Hong Kong, Shatin, Hong Kong
| | - Tony Mak
- Department of Surgery, the Chinese University of Hong Kong, Shatin, Hong Kong
| | - Simon Ng
- Department of Surgery, the Chinese University of Hong Kong, Shatin, Hong Kong
| | - Hans Gregersen
- Department of Surgery, the Chinese University of Hong Kong, Shatin, Hong Kong.,California Medical Innovations Institute, San Diego, CA, USA
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Zhao J, Liao D, Wilkens R, Krogh K, Glerup H, Gregersen H. Bowel stiffness associated with histopathologic scoring of stenosis in patients with Crohn's disease. Acta Biomater 2021; 130:332-342. [PMID: 34119715 DOI: 10.1016/j.actbio.2021.06.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 05/31/2021] [Accepted: 06/03/2021] [Indexed: 12/11/2022]
Abstract
BACKGROUND AND AIMS Intestinal stenosis is a common complication of Crohn's Disease (CD). Stenosis is associated with alteration of bowel mechanical properties. This study aims to quantitate the mechanical properties of the intestinal stenosis and to explore associations between histology and mechanical remodeling at stenotic intestinal sites in CD patients. METHODS Intestinal segments from stenotic sites were studied in vitro from 19 CD patients. A luminal catheter with a bag was used to stepwise pressurize the intestinal segments from 0-100 cmH2O with 10 cmH2O increments. B-mode ultrasound images were obtained at the narrowest part of the stenosis at each pressure level and morphometric parameters were obtained from ultrasound images. The mechanical behavior of the stenotic tissue were characterized by using an isotropic three dimensional strain energy function in Demiray model form, the mechanical constants were obtained by fitting the model to the recorded intraluminal pressure and the inner radius of the stenotic segment of the small bowel. Grading scores were used for histological analysis of inflammation, fibrosis, muscular hypertrophy and adipocyte proliferation in the intestinal layers. The collagen area fraction in intestinal layers was also calculated. Associations between histological and the mechanical constants (stiffness) were analyzed. RESULTS Chronic inflammation was mainly located in mucosa whereas fibrosis was found in submucosa. The mechanical remodeling was performed with changed mechanical constants ranged between 0.35-13.68kPa. The mechanical properties changes were associated mainly with chronic inflammation, fibrosis and combination of inflammation and fibrosis (R>0.69, P<0.001). Furthermore, the mechanical properties correlated with the collagen fraction in submucosa and muscular layers (R>0.53, P<0.05). CONCLUSIONS We quantitated the intestinal stenosis stiffness. Associations were found between bowel mechanical remodeling and histological changes at the stenotic site in CD patients. STATEMENT OF SIGNIFICANCE Although intestinal ultrasonography, CT and MRI can be used to diagnose Crohn's Disease (CD)-associated bowel strictures, these techniques may not have sufficient accuracy and resolution to differentiate predominantly inflammatory strictures from predominantly fibrotic strictures. The present study aims to quantitate the mechanical remodeling of intestinal stenosis and to explore the associations between histological parameters and mechanical properties at the intestinal stenotic sites in CD patients. For the first time, we quantitatively demonstrated that the mechanical properties of the intestinal wall in CD stenosis are associated with the chronic inflammation, fibrosis and collagen fraction in the intestinal layers. The results of this study may facilitate design and development of artificial biomaterials for gastrointestinal organs. The potential clinical implication of this study is that the histological characteristics in patients with CD can be predicted clinically by means of inflammation and fibrosis assessment in conjunction with tissue stiffness measurement.
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Affiliation(s)
- Jingbo Zhao
- Standard (Chongqing) Pathological Diagnosis Center. No. 8 Xiyuan North Road, Shapingba District, Chongqing, China; Mech-Sense, Department of Gastroenterology and Hepatology, Aalborg University Hospital, Denmark; Giome Academia, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Donghua Liao
- Mech-Sense, Department of Gastroenterology and Hepatology, Aalborg University Hospital, Denmark; Giome Academia, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
| | - Rune Wilkens
- Gastrounit, Division of Medicine, Hvidovre Hospital, University of Copenhagen, Copenhagen, Denmark; Diagnostic Centre, University Research Clinic for Innovative Patient Pathways, Silkeborg Regional Hospital, Silkeborg, Denmark
| | - Klaus Krogh
- Neurogastroenterology Unit, Department of Hepatology and Gastroenterology, Aarhus University Hospital, Aarhus, Denmark
| | - Henning Glerup
- Diagnostic Centre, University Research Clinic for Innovative Patient Pathways, Silkeborg Regional Hospital, Silkeborg, Denmark
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Gregersen H, Chen SC, Leung WW, Wong C, Mak T, Ng S, Daming S, Futaba K. Characterization of Patients With Obstructed Defecation and Slow Transit Constipation With a Simulated Stool. Clin Transl Gastroenterol 2021; 12:e00354. [PMID: 33949343 PMCID: PMC8099406 DOI: 10.14309/ctg.0000000000000354] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 03/29/2021] [Indexed: 12/12/2022] Open
Abstract
INTRODUCTION Defecatory disorders including obstructed defecation (OD) are currently diagnosed using specialized investigations including anorectal manometry and the balloon expulsion test. Recently, we developed a simulated stool named Fecobionics that provides a novel type of pressure measurements and analysis. The aim was to study OD phenotypes compared with slow transit constipation (STC) patients and normal subjects (NS). METHODS Fecobionics expulsion parameters were assessed in an interventional study design. The Fecobionics device contained pressure sensors at the front, rear, and inside a bag. All constipation patients had colon transit study, defecography, anorectal manometry, and balloon expulsion test performed. The Fecobionics bag was distended in the rectum until desire-to-defecate in 26 OD compared with 8 STC patients and 10 NS. Rear-front pressures (preload-afterload parameters) and defecation indices (DIs) were compared between groups. RESULTS The Wexner constipation scoring system score was 13.8 ± 0.9 and 14.6 ± 1.5 in the OD and STC patients (P > 0.5). The median desire-to-defecate volume was 80 (quartiles 56-80), 60 (54-80), and 45 (23-60) mL in OD, STC, and NS, respectively (P < 0.01). The median expulsion duration was 37 (quartiles 15-120), 6 (3-11), and 11 (8-11) seconds for the 3 groups (P < 0.03). Fecobionics rear-front pressure diagrams demonstrated clockwise loops with distinct phenotype differences between OD and the other groups. Most DIs differed between OD and the other groups, especially those based on the anal afterload reflecting the nature of OD constipation. Several OD subtypes were identified. DISCUSSION Fecobionics obtained novel pressure phenotypes in OD patients. DIs showed pronounced differences between groups. Larger studies are needed on OD subtyping.
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Affiliation(s)
- Hans Gregersen
- Department of Surgery, the Chinese University of Hong Kong, Shatin, Hong Kong
| | - Ssu-Chi Chen
- Department of Surgery, the Chinese University of Hong Kong, Shatin, Hong Kong
| | - Wing Wa Leung
- Department of Surgery, the Chinese University of Hong Kong, Shatin, Hong Kong
| | - Cherry Wong
- Department of Surgery, the Chinese University of Hong Kong, Shatin, Hong Kong
| | - Tony Mak
- Department of Surgery, the Chinese University of Hong Kong, Shatin, Hong Kong
| | - Simon Ng
- Department of Surgery, the Chinese University of Hong Kong, Shatin, Hong Kong
| | - Sun Daming
- School of Microelectronics and Communication Engineering, Chongqing University, Shapingba, China
| | - Kaori Futaba
- Department of Surgery, the Chinese University of Hong Kong, Shatin, Hong Kong
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Chen SC, Futaba K, Leung WW, Wong C, Mak T, Ng S, Gregersen H. Fecobionics assessment of the effect of position on defecatory efficacy in normal subjects. Tech Coloproctol 2021; 25:559-568. [PMID: 33779850 DOI: 10.1007/s10151-021-02439-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 03/20/2021] [Indexed: 12/15/2022]
Abstract
BACKGROUND Defecation is a complex process and up to 25% of the population suffer from symptoms of defecatory dysfunction. For functional testing, diagnostics, and therapy of anorectal disorders, it is important to know the optimal defecation position. is The aim of this study was to evaluate defecation pressure patterns in side lying, seated and squatting defecation positions in normal subjects using a simulated stool device called Fecobionics. METHODS The Fecobionics expulsion parameters were assessed in an interventional study design conducted from May 29 to December 9 2019. Subjects were invited to participate in the study through advertisement at The Chinese University of Hong Kong. The Fecobionics device consisted of a core containing pressure sensors at the front (caudal end) and rear (cranial end) and a polyester-urethane bag spanning most of the core length which also contained sensors. The Fecobionics bag was distended to 50 ml in the rectum of normal subjects (no present and past symptoms of defecatory disorders, no prior abdominal surgery, medication or chronic diseases). Studies were done in side lying (left lateral recumbent position), seated (hip flexed 90°) and squatting position (hip flexed 25°). Pressure endpoints including the rear-front pressure diagram and defecation indices were compared between positions. RESULTS Twelve subjects (6 females/6 males, mean age 26.3 ± 2.6 [19.0-48.0] years) were included and underwent the planned procedures. The resting anal pressure for side lying and seated positions were 33.1 ± 4.1 cmH2O and 37.1 ± 4.0 cmH2O (p > 0.3). The anal squeeze pressure for side lying and seated positions were 98.4 ± 6.9 cmH2O and 142.3 ± 16.4 cmH2O (p < 0.05). The expulsion duration for the side lying, seated and squatting positions were 108.9 ± 8.3 s, 15.0 ± 2.1 s and 16.1 ± 2.9 s, respectively (p < 0.01 between lying and the two other positions). The maximum evacuation pressure for seated and squatting were 130.1 ± 12.4 cmH2O and 134.0 ± 11.1 cmH2O (p > 0.5). Rear-front pressure diagrams and distensibility indices demonstrated distinct differences in pressure patterns between the side lying position group and the other positions. CONCLUSIONS The delay in expelling the Fecobionics device in the lying position was associated with dyssynergic pressure patterns on the device. Quantitative differences were not found between the seated and squatting position. Trial Registration http://www.clinicaltrials.gov Identifier: NCT03317938.
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Affiliation(s)
- S-C Chen
- GIOME, Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, 4/F, Clinical Sciences Building, Shatin, Hong Kong, China
| | - K Futaba
- GIOME, Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, 4/F, Clinical Sciences Building, Shatin, Hong Kong, China
| | - W W Leung
- GIOME, Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, 4/F, Clinical Sciences Building, Shatin, Hong Kong, China
| | - C Wong
- GIOME, Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, 4/F, Clinical Sciences Building, Shatin, Hong Kong, China
| | - T Mak
- GIOME, Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, 4/F, Clinical Sciences Building, Shatin, Hong Kong, China
| | - S Ng
- GIOME, Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, 4/F, Clinical Sciences Building, Shatin, Hong Kong, China
| | - H Gregersen
- GIOME, Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, 4/F, Clinical Sciences Building, Shatin, Hong Kong, China.
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Abstract
OBJECTIVE Fecobionics was used to assess pressures, orientation, bending, shape, and cross-sectional area (CSA) changes during defecation. This study aimed to evaluate the device feasibility and performance in swine. APPROACH Twelve pigs had wired or wireless Fecobionics devices inserted in the rectum. The bag was distended to simulate feces in the rectum. Fecobionics data were acquired simultaneously during the whole experiment. Six pigs were euthanized immediately after the procedure for evaluation of acute injury to anorectum (acute group). The remaining pigs lived two weeks before euthanasia for evaluation of long-term tissue damage and inflammation (chronic group). Signs of discomfort were monitored. MAIN RESULTS All animals tolerated the experiment well. The chronic animals showed normal behavior after the procedure. Mucosal damage, bleeding, or inflammation was not found in either group. Fecobionics was defecated 1 min 35 s-61 min 0 s (median 8 min 58 s) after insertion. The defecation lasted 0 min 20 s-4 min 25 s (median 1 min 52 s). The device was almost straight inside rectum (160°-180°) but usually bended 5°-20° during contractions. The three pressure sensors showed simultaneous and identical increase during rectal or abdominal muscle contractions, indicating the location inside rectum. During defecation, the maximum rear pressure was 114.1 ± 14.3 cmH2O whereas the front pressure gradually decreased to 0 cmH2O, indicating the front passed anus. CSA decreased from 1017.1 ± 191.0 mm2 to 530.7 ± 46.5 mm2 when the probe passed from the rectum through the anal canal. SIGNIFICANCE Fecobionics provides defecatory measurements under physiological conditions in pigs without inducing tissue damage.
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Affiliation(s)
- Yanmin Wang
- California Medical Innovations Institute, San Diego, CA, United States of America
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Sun D, Liao D, Chen SC, Wong C, Wah Leung W, Futaba K, Mak T, Ng S, Gregersen H. Mechanophysiological analysis of anorectal function using simulated feces in human subjects. J Adv Res 2021; 28:245-254. [PMID: 33364060 PMCID: PMC7753961 DOI: 10.1016/j.jare.2020.07.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 07/06/2020] [Accepted: 07/07/2020] [Indexed: 12/20/2022] Open
Abstract
INTRODUCTION Defecation is a complex process that is difficult to study and analyze. OBJECTIVES Here, we present new analytical tools to calculate frictional force and tension during expulsion of the Fecobionics simulated stool in human subjects. METHODS The 12-cm-long Fecobionics device contained pressure sensors, motion processor units for measurement of orientation and bending, and impedance rings for measurement of cross-sectional areas. Eight normal subjects defecated Fecobionics. The bending angle of the device, frictional force between the device and the surrounding tissue, and the stretch tensions were calculated. RESULTS The bending angle and pressures changed during expulsion with the maximum pressure recorded at the rear. The averaged circumferential tension, longitudinal tension and friction force in each subject were associated with the front-rear pressure difference (r > 0.7, p < 0.005). The peak circumferential tension, longitudinal tension, and friction force immediately before expulsion of the rear were significantly higher compared to when the front entered the anal canal (F = 164.7, p < 0.005; F = 152.1, p < 0.005; F = 71.4, p < 0.005; respectively.). CONCLUSION This study shows that Fecobionics obtained reliable data under physiological conditions. Mechanical features such as frictional force and stretch tensions were assessable during Fecobionics expulsion.
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Affiliation(s)
- Daming Sun
- School of Microelectronics and Communication Engineering, Chongqing University, Shapingba, Chongqing, 400044, China
| | - Donghua Liao
- Mech-Sense, Department of Gastroenterology and Hepatology, Aalborg University Hospital, Denmark
- GIOME Academia, Department of Clinical Medicine, Aarhus University, DK-8200 Aarhus, Denmark
| | - Ssu Chi Chen
- Department of Surgery, Clinical Sciences Bldg., Prince of Wales Hospital, Shatin, Hong Kong
| | - Cherry Wong
- Department of Surgery, Clinical Sciences Bldg., Prince of Wales Hospital, Shatin, Hong Kong
| | - Wing Wah Leung
- Department of Surgery, Clinical Sciences Bldg., Prince of Wales Hospital, Shatin, Hong Kong
| | - Kaori Futaba
- Department of Surgery, Clinical Sciences Bldg., Prince of Wales Hospital, Shatin, Hong Kong
| | - Tony Mak
- Department of Surgery, Clinical Sciences Bldg., Prince of Wales Hospital, Shatin, Hong Kong
| | - Simon Ng
- Department of Surgery, Clinical Sciences Bldg., Prince of Wales Hospital, Shatin, Hong Kong
| | - Hans Gregersen
- Department of Surgery, Clinical Sciences Bldg., Prince of Wales Hospital, Shatin, Hong Kong
- California Medical Innovations Institute, USA
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Chen SC, Futaba K, Leung WW, Wong C, Mak T, Ng S, Gregersen H. Simulated stool for assessment of anorectal physiology. Am J Physiol Gastrointest Liver Physiol 2020; 319:G462-G468. [PMID: 32783614 DOI: 10.1152/ajpgi.00242.2020] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Fecal continence is maintained by several mechanisms including anatomical factors, anorectal sensation, rectal compliance, stool consistency, anal muscle strength, mobility, and psychological factors. The homeostatic balance is easily disturbed, resulting in symptoms including fecal incontinence and constipation. Current technologies for assessment of anorectal function have limitations. Overlap exist between data obtained in different patient groups, and there is lack of correlation between measurements and symptoms. This review describes a novel technology named Fecobionics for assessment of anorectal physiology. Fecobionics is a simulated stool, capable of dynamic measurements of a variety of variables during defecation in a single examination. The data facilitate novel analysis of defecatory function as well as providing the foundation for modeling studies of anorectal behavior. The advanced analysis can enhance our physiological understanding of defecation and future interdisciplinary research for unraveling defecatory function, anorectal sensory-motor disorders, and symptoms. This is a step in the direction of improved diagnosis of anorectal diseases.
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Affiliation(s)
- Ssu-Chi Chen
- Department of Surgery, the Chinese University of Hong Kong, Shatin, Hong Kong
| | - Kaori Futaba
- Department of Surgery, the Chinese University of Hong Kong, Shatin, Hong Kong
| | - Wing Wa Leung
- Department of Surgery, the Chinese University of Hong Kong, Shatin, Hong Kong
| | - Cherry Wong
- Department of Surgery, the Chinese University of Hong Kong, Shatin, Hong Kong
| | - Tony Mak
- Department of Surgery, the Chinese University of Hong Kong, Shatin, Hong Kong
| | - Simon Ng
- Department of Surgery, the Chinese University of Hong Kong, Shatin, Hong Kong
| | - Hans Gregersen
- Department of Surgery, the Chinese University of Hong Kong, Shatin, Hong Kong
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Zifan A, Mittal RK, Kunkel DC, Swartz J, Barr G, Tuttle LJ. Loop analysis of the anal sphincter complex in fecal incontinent patients using functional luminal imaging probe. Am J Physiol Gastrointest Liver Physiol 2020; 318:G66-G76. [PMID: 31736339 PMCID: PMC6985842 DOI: 10.1152/ajpgi.00164.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Cardiac loops have been used extensively to study myocardial function. With changes in cardiac pump function, loops are shifted to the right or left. Functional luminal imaging probe (FLIP) recordings allow for loop analysis of the anal sphincter and puborectalis muscle (PRM) function. The goal was to characterize anal sphincter area-pressure/tension loop changes in fecal incontinence (FI) patients. Fourteen healthy subjects and 14 patients with FI were studied. A custom-designed FLIP was placed in the vagina and then in the anal canal, and deflated in 20-ml steps, from 90 to 30 ml. At each volume, subjects performed maximal voluntary squeezes. Area-pressure (AP) and area-tension (AT) loops were generated for each squeeze cycle. Three-dimensional ultrasound imaging of the anal sphincter and PRM were obtained to determine the relationship between anal sphincter muscle damage and loop movements. With the increase in bag volume, AP loops and AT loops shifted to the right and upward in normal subjects (both anal and vaginal). The shift to the right was greater, and the upward movement was less in FI patients. The difference in the location of AP loops and AT loops was statistically significant at volumes of 50 ml to 90 ml (P < 0.05). A similar pattern was found in the vaginal loops. There is a significant relationship between the damage to the anal sphincter and PRM, and loop location of FI patients. We propose AP and AT loops as novel ways to assess the anal sphincter and PRM function. Such loops can be generated by real-time measurement of pressure and area within the anal canal.NEW & NOTEWORTHY We describe the use of area-pressure (AP) and area-tension (AT)-loop analysis of the anal sphincters and puborectalis muscles in normal subjects and fecal incontinent patients using the functional luminal imaging probe (FLIP). There are differences in the magnitude of the displacement of the loops with increase in the FLIP bag volume between normal subjects and patients with fecal incontinence. The latter group shifts more to the right in AP and AT space.
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Affiliation(s)
- Ali Zifan
- 1Division of Gastroenterology, Department of Medicine, University of California San Diego, California
| | - Ravinder K. Mittal
- 1Division of Gastroenterology, Department of Medicine, University of California San Diego, California
| | - David C. Kunkel
- 1Division of Gastroenterology, Department of Medicine, University of California San Diego, California
| | - Jessica Swartz
- 2Doctor of Physical Therapy Program, School of Exercise and Nutritional Sciences, San Diego State University, San Diego, California
| | - Garrett Barr
- 2Doctor of Physical Therapy Program, School of Exercise and Nutritional Sciences, San Diego State University, San Diego, California
| | - Lori J. Tuttle
- 2Doctor of Physical Therapy Program, School of Exercise and Nutritional Sciences, San Diego State University, San Diego, California
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Liao D, Chen AS, Lo KM, Zhao J, Futaba K, Gregersen H. Theoretical tools to analyze anorectal mechanophysiological data generated by the Fecobionics device. J Biomech Eng 2019; 141:2737406. [PMID: 31242283 DOI: 10.1115/1.4044134] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Indexed: 12/14/2022]
Abstract
A mechanical approach is needed for understanding anorectal function and defecation. Fecal continence is achieved by several interacting mechanisms including anatomical factors, anorectal sensation, rectal compliance, stool consistency, anal muscle strength, motility, and psychological factors. The balance is easily disturbed, resulting in symptoms such as fecal incontinence and constipation. Novel technologies have been developed in recent years for studying anorectal function. Especially the Fecobionics device, a simulated feces, has gained attention recently. This facilitates new analysis of anorectal mechanical function. In this study a theoretical model is developed to analyze anorectal mechanophysiological data generated by the Fecobionics device. Theoretical approaches can enhance future interdisciplinary research for unraveling defecatory function, sensory-motor disorders and symptoms. This is a step in the direction of personalized treatment for gastrointestinal disorders based on optimized subtyping of anorectal disorders.
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Affiliation(s)
- Donghua Liao
- GIOME Academia, Department of Clinical Medicine, Aarhus University, Incuba, Skejby, DK-8200 Aarhus, Denmark
| | - Abbey Sc Chen
- GIOME, Department of Surgery, 4/F, Clinical Sciences Building, Prince of Wales Hospital, Shatin, Hong Kong
| | - Kar Man Lo
- Giome DB, Unit 16D, Crystal Court, Discovery Bay, N.T., Hong Kong
| | - Jingbo Zhao
- GIOME Academia, Department of Clinical Medicine, Inkuba, Aarhus University, DK-8200 Aarhus, Denmark
| | - Kaori Futaba
- GIOME, Department of Surgery, 4/F, Clinical Sciences Building, Prince of Wales Hospital, Shatin, Hong Kong
| | - Hans Gregersen
- GIOME, Department of Surgery, 4/F, Clinical Sciences Building, Prince of Wales Hospital, Shatin, Hong Kong; California Medical Innovations Institute, 11007 Roselle St., 92122 San Diego, California, USA
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