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Sun D, Lo KM, Chen SC, Leung WW, Wong C, Mak T, Ng S, Futaba K, Gregersen H. The rectum, anal sphincter and puborectalis muscle show different contraction wave forms during prolonged measurement with a simulated feces. Sci Rep 2024; 14:432. [PMID: 38172283 PMCID: PMC10764324 DOI: 10.1038/s41598-023-50655-7] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 12/22/2023] [Indexed: 01/05/2024] Open
Abstract
Contractile patterns in rectum, puborectalis muscle and anal sphincter must be studied to understand defecation. Six subjects had contractile waveforms studied with Fecobionics. Symptom questionnaires, balloon expulsion test and anorectal manometry were done for reference. The Fecobionics bag was filled in rectum to urge-to-defecate volume and measurements were done for 4 h before the subjects attempted to evacuate the device. Pressures and bend angle (BA) variations were analyzed with Fast Fourier Transformation. Four normal subjects exhibited low frequency waves (< 0.06 Hz) for pressures and BA. The waves were uncoordinated between recordings, except for rear and bag pressures. Peak wave amplitudes occurred at 0.02-0.04 Hz. Pressures and the BA differed for peak 1 (p < 0.001) and peak 2 amplitudes (p < 0.005). The front pressure amplitude was bigger than the others (rear and BA, p < 0.05; bag, p < 0.005) for peak 1, and bigger than bag pressure (p < 0.005) and BA (p < 0.05) for peak 2. One subject was considered constipated with lower front pressure amplitudes compared to normal subjects and increased amplitudes for other parameters. The sixth subject was hyperreactive and differed from the other subjects. In conclusion, the rectum, anal sphincter and puborectalis muscle showed different contraction waves during prolonged measurements. The data call for larger studies to better understand normal defecation, feces-withholding patterns, and the implications on anorectal disorders.
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Affiliation(s)
- Daming Sun
- Chongqing Engineering Research Center of Medical Electronics and Information Technology, Chongqing University of Posts and Telecommunications, Chongqing, China
| | - Kar Man Lo
- California Medical Innovations Institute, 11107 Roselle St., San Diego, CA, 92121, USA
| | - 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
| | - Kaori Futaba
- Department of Surgery, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Hans Gregersen
- California Medical Innovations Institute, 11107 Roselle St., San Diego, CA, 92121, USA.
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Gregersen H, Sun D, Field F, Combs W, Christensen P, Mousa H, Moawad FJ, Eisenstein S, Kassab GS. Fecobionics in proctology: review and perspectives. Surg Open Dig Adv 2023; 12:100117. [PMID: 38313319 PMCID: PMC10838111 DOI: 10.1016/j.soda.2023.100117] [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] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/06/2024]
Abstract
Fecobionics is a novel integrated technology for assessment of anorectal function. It is a defecatory test with simultaneous measurements of pressures, orientation, and device angle (a proxy of the anorectal angle). Furthermore, the latest Fecobionics prototypes measure diameters (shape) using impedance planimetry during evacuation of the device. The simultaneous measurement of multiple variables in the integrated test allows new metrics to be developed including more advanced novel defecation indices, enabling mechanistic insight in the defecation process at an unprecedented level in patients with anorectal disorders including patients suffering from obstructed defecation, fecal incontinence, and low anterior resection syndrome. The device has the consistency and shape of a normal stool (type 3-4 on the Bristol Stool Form Scale). Fecobionics has been validated on the bench and in animal studies and used in clinical trials to study defecation phenotypes in normal human subjects and patients with obstructed defecation, fecal incontinence, and low anterior resection syndrome after rectal cancer surgery. Subtypes have been defined, especially of patients with obstructed defecation. Furthermore, Fecobionics has been used to monitor biofeedback therapy in patients with fecal incontinence to predict the outcome of the therapy (responder versus non-responder). Most Fecobionics studies showed a closer correlation to symptoms as compared to current technologies for anorectal assessment. The present article outlines previous and ongoing work, and perspectives for future studies in proctology, including in physiological assessment of function, diagnostics, monitoring of therapy, and as a tool for biofeedback therapy.
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Affiliation(s)
- H Gregersen
- California Medical Innovations Institute, San Diego, California, USA
| | - D Sun
- School of Microelectronics and Communication Engineering, Chongqing University, Chongqing, China
| | - F Field
- S3DT Holdings, San Diego, California, USA
| | - W Combs
- S3DT Holdings, San Diego, California, USA
| | - P Christensen
- Department of Surgery, Aarhus University Hospital, Aarhus, Denmark
| | - H Mousa
- CHOP, University of Pennsylvania, Philadelphia, Pennsylvania
| | - F J Moawad
- Scripps Clinic, Division of Gastroenterology, La Jolla, California, USA
| | - S Eisenstein
- Department of Surgery, University of California San Diego, La Jolla, California, USA
| | - G S Kassab
- California Medical Innovations Institute, San Diego, California, USA
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Gregersen H, Mittal RK. Rectal contractility in patients with fecal incontinence and obstructed defecation compared to normal subjects. Gastro Hep Adv 2023; 2:656-659. [PMID: 37464998 PMCID: PMC10353715 DOI: 10.1016/j.gastha.2023.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2023]
Affiliation(s)
- Hans Gregersen
- California Medical Innovations Institute, San Diego, California, USA
| | - Ravinder K. Mittal
- Division of Gastroenterology, University of California San Diego, California, USA
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Lo KM, Sun D, Chen SC, Leung WW, Wong C, Mak T, Ng S, Futaba K, Gregersen H. Defecatory Function Studies Using the Fecobionics Device Are Repeatable. Dig Dis Sci 2023; 68:2501-2507. [PMID: 36879178 DOI: 10.1007/s10620-023-07889-2] [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] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Accepted: 02/17/2023] [Indexed: 03/08/2023]
Abstract
BACKGROUND Only limited data exist on repeatability of anorectal studies with the established physiological and clinical technologies for assessment of anorectal function. Fecobionics is a new multi-sensor simulated feces that provide data by integrating elements from current tests. AIMS To study repeatability of anorectal data obtained with the Fecobionics device. METHODS We assessed the database of Fecobionics studies to determine how many repeated studies were done. From a total of 260 Fecobionics studies, 19 subjects with repeated studies using approximately the same protocol and prototype were identified. Key pressure and bending parameters were assessed and the repeatability analyzed using Bland Altman plots. Furthermore, the inter- and intra-individual coefficient of variation (CV) were computed. RESULTS Fifteen subjects (5F/10 M) with repeated studies were normal subjects, three were patients with fecal incontinence and one subject suffered from chronic constipation. The main analysis was conducted on the cohort of normal subjects. The bias for 11 parameters were within the confidence interval, whereas two were slightly outside. The interindividual CV was lowest for the bend angle (10.1-10.7) and between 16.3 and 51.6 for the pressure parameters. The intra-individual CVs were approximately half of the inter-individual CVs, spanning from 9.7 to 27.6. CONCLUSION All data from normal subjects were within previously defined normality. The Fecobionics data showed acceptable repeatability with bias within the confidence limits for almost all parameters. The intra-individual CV was much lower than the inter-individual CV. Dedicated large-scale studies are warranted to evaluate the influence of age, sex, and disease on repeatability as well as comparing between technologies.
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Affiliation(s)
- Kar Man Lo
- California Medical Innovations Institute, San Diego, CA, USA
| | - Daming Sun
- Chongqing Engineering Research Center of Medical Electronics and Information Technology, Chongqing University of Posts and Telecommunications, Chongqing, China
| | - 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
| | - Kaori Futaba
- Department of Surgery, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Hans Gregersen
- California Medical Innovations Institute, San Diego, CA, USA.
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Gregersen H, Wang Y, Field F, Wang M, Lo KM, Guo X, Combs W, Kassab GS. Anorectal volume-pressure relations, contraction work, and flow during defecation. Biomech Model Mechanobiol 2022; 21:1613-1621. [PMID: 35908095 PMCID: PMC9633562 DOI: 10.1007/s10237-022-01610-4] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 07/01/2022] [Indexed: 11/24/2022]
Abstract
Fecobionics is an integrated device that has shown promise for assessment of anorectal function. We used a wireless Fecobionics prototype to visualize defecatory patterns and to compute volume-pressure, contraction work, and flow. Twelve normal subjects were studied. The probe was 10 cm-long and contained pressure sensors and electrodes for impedance planimetry. Pressures, diameters, and volume data during defecation were analyzed. The bag was distended inside rectum to the urge-to-defecate level where after the subjects were asked to evacuate. The contraction work and defecatory flow were computed from the volume changes during expulsion. The minimum anal diameter during the evacuation was 17.6 ± 1.5 mm. The middle diameter recording was 10-20% lower than the front diameter channels and 10-20% bigger than the rear channels. The bag volume at urge correlated with the minimum diameter (r = 0.63). The diameter-pressure and volume-pressure loops were counterclockwise with phases of bag filling, isometric contraction, ejection and anal passage. The defecatory contraction work was 3520 ± 480 mL × cmH2O. The maximum flow during defecation was 302 ± 33 mL/s. The flow was associated with the anal diameter (r = 0.84) but not with the rectoanal pressure gradient (r = 0.14). Volume-pressure loops have a tremendous impact on the understanding of cardiopulmonary pathophysiology. Future studies will shed light on potential clinical impact in defecatory pathophysiology.
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Affiliation(s)
- Hans Gregersen
- California Medical Innovations Institute, 11107 Roselle St., San Diego, CA, 92121, USA.
| | - Yanmin Wang
- California Medical Innovations Institute, 11107 Roselle St., San Diego, CA, 92121, USA
| | | | | | - Kar Man Lo
- California Medical Innovations Institute, 11107 Roselle St., San Diego, CA, 92121, USA
| | - Xiaomei Guo
- California Medical Innovations Institute, 11107 Roselle St., San Diego, CA, 92121, USA
| | | | - Ghassan S Kassab
- California Medical Innovations Institute, 11107 Roselle St., San Diego, CA, 92121, USA
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Gregersen H, Wang Y, Field F, Wang M, Lo KM, Guo X, Combs W, Kassab GS. Feasibility study of defecation studied with a wireless Fecobionics probe in normal subjects. Physiol Rep 2022; 10:e15338. [PMID: 35656707 PMCID: PMC9163794 DOI: 10.14814/phy2.15338] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 05/12/2022] [Accepted: 05/17/2022] [Indexed: 06/15/2023] Open
Abstract
Several technologies have been developed for assessing anorectal function including the act of defecation. We used a new prototype of the Fecobionics technology, a multi-sensor simulated feces, to visualize defecatory patterns and introduced new metrics for anorectal physiology assessment in normal subjects. Fourteen subjects with normal fecal incontinence and constipation questionnaire scores were studied. The 10-cm-long Fecobionics device provided measurements of axial pressures, orientation, bending, and shape. The Fecobionics bag was distended to the urge-to-defecate level inside rectum where after the subjects were asked to evacuate. Physiological evacuation parameters were assessed. Special attention was paid to the Fecobionics rectoanal pressure gradient (F-RAPG) during evacuation. Anorectal manometry (ARM) and balloon expulsion test (BET) were done as references. The user interface displayed the fine coordination between pressures, orientation, bending angle, and shape. The pressures showed that Fecobionics was expelled in 11.5 s (quartiles 7.5 and 18.8s), which was shorter than the subjectively reported expulsion time of the BET balloon. Six subjects did not expel the BET balloon within 2 min. The F-RAPG was 101 (79-131) cmH2 O, whereas the ARM-RAPG was -28 (-5 to -47) cmH2 0 (p < 0.001). There was no association between the two RAPGs (r2 = 0.19). Fecobionics showed paradoxical contractions in one subject (7%) compared to 12 subjects with ARM (86%). Fecobionics obtained novel physiological data. Defecatory patterns and data are reported and can be used to guide larger-scale studies in normal subjects and patients with defecatory disorders. In accordance with other studies, this Fecobionics study questions the value of the ARM-RAPG.
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Affiliation(s)
- Hans Gregersen
- California Medical Innovations InstituteSan DiegoCaliforniaUSA
| | - Yanmin Wang
- California Medical Innovations InstituteSan DiegoCaliforniaUSA
| | | | | | - Kar Man Lo
- California Medical Innovations InstituteSan DiegoCaliforniaUSA
| | - Xiaomei Guo
- California Medical Innovations InstituteSan DiegoCaliforniaUSA
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Patel B, Gizzi A, Hashemi J, Awakeem Y, Gregersen H, Kassab G. Biomechanical constitutive modeling of the gastrointestinal tissues: a systematic review. Mater Des 2022; 217:110576. [PMID: 35935127 PMCID: PMC9351365 DOI: 10.1016/j.matdes.2022.110576] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The gastrointestinal (GI) tract is a continuous channel through the body that consists of the esophagus, the stomach, the small intestine, the large intestine, and the rectum. Its primary functions are to move the intake of food for digestion before storing and ultimately expulsion of feces. The mechanical behavior of GI tissues thus plays a crucial role for GI function in health and disease. The mechanical properties are characterized by a biomechanical constitutive model, which is a mathematical representation of the relation between load and deformation in a tissue. Hence, validated biomechanical constitutive models are essential to characterize and simulate the mechanical behavior of the GI tract. Here, a systematic review of these constitutive models is provided. This review is limited to studies where a model of the strain energy function is proposed to characterize the stress-strain relation of a GI tissue. Several needs are identified for more advanced modeling including: 1) Microstructural models that provide actual structure-function relations; 2) Validation of coupled electro-mechanical models accounting for active muscle contractions; 3) Human data to develop and validate models. The findings from this review provide guidelines for using existing constitutive models as well as perspective and directions for future studies.
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Affiliation(s)
- Bhavesh Patel
- California Medical Innovations Institute, 11107 Roselle St, San Diego, CA 92121, USA
| | - Alessio Gizzi
- Department of Engineering, Campus Bio-Medico University of Rome, Via A. del Portillo 21, 00128 Rome, IT
| | - Javad Hashemi
- California Medical Innovations Institute, 11107 Roselle St, San Diego, CA 92121, USA
| | - Yousif Awakeem
- California Medical Innovations Institute, 11107 Roselle St, San Diego, CA 92121, USA
| | - Hans Gregersen
- California Medical Innovations Institute, 11107 Roselle St, San Diego, CA 92121, USA
| | - Ghassan Kassab
- California Medical Innovations Institute, 11107 Roselle St, San Diego, CA 92121, USA
- Corresponding author , Tel: 001-858-249-7400, Fax: 001-858-249-7419, (Ghassan Kassab)
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Futaba K, Chen SC, Leung WW, Wong C, Mak T, Ng S, Gregersen H. Fecobionics Evaluation of Biofeedback Therapy in Patients With Fecal Incontinence. Clin Transl Gastroenterol 2022; 13:e00491. [PMID: 35363631 PMCID: PMC9132520 DOI: 10.14309/ctg.0000000000000491] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Accepted: 03/21/2022] [Indexed: 11/17/2022] Open
Abstract
INTRODUCTION Biofeedback therapy (BFT) is a well-known treatment for functional anorectal disorders. The effect of BFT was monitored in fecal incontinence (FI) patients with the Fecobionics test and with the conventional technologies, anorectal manometry (ARM) and balloon expulsion test (BET). METHODS Studies were performed in 12 patients before and after 8 weeks of biofeedback training. The Fecal Incontinence Severity Index (FISI) score was obtained. Anal resting and squeeze pressures were measured before the bag was distended in the rectum until urge to defecate. Pressure recordings were made during Fecobionics evacuation. RESULTS BFT resulted in 24% reduction in FISI scores (P < 0.01). Seven patients were characterized as responders. Anal pressures, the urge-to-defecate volume, and defecatory parameters did not change significantly during BFT. For ARM-BET, the maximum anal squeeze pressure, the urge-to-defecate volume, and the expulsion time were lower after BFT compared with those before BFT (P < 0.05). For Fecobionics, the change in urge volume (r = 0.74, P < 0.05) and the change in defecation index (r = 0.79, P < 0.01) were associated with the change in FISI score. None of the ARM-BET parameters were associated with the change in FISI score. It was studied whether any pre-BFT data could predict treatment success. The Fecobionics expulsion duration and the defecation index predicted the outcome (P < 0.05). The defecation index had a sensitivity of 100% and a specificity of 72%. None of the ARM-BET parameters predicted the outcome (all P > 0.2). DISCUSSION Fecobionics was used as a tool to monitor the effect of BFT and proved better than conventional technologies for monitoring and predicting the outcome in the FISI score.
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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, San Diego, California, 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] [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: 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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Gregersen H, Sun D, Chen S, Leung W, Wong C, Mak T, Ng S, Futaba K, Lo KM, Kassab G. New developments in defecatory studies based on biomechatronics. J Adv Res 2022; 35:1-11. [PMID: 35003792 PMCID: PMC8721237 DOI: 10.1016/j.jare.2021.05.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 03/11/2021] [Accepted: 05/16/2021] [Indexed: 02/07/2023] Open
Abstract
Introduction Defecation is a complex process that is difficult to study and analyze directly. In anorectal disease conditions, the defecation process may be disturbed, resulting in symptoms including fecal incontinence and constipation. Current state-of-the-art technology measures various aspects of anorectal function but detailed analysis is impossible because they are stand-alone tests rather than an integrated multi-dimensional test. Objectives The need for physiologically-relevant and easy-to-use diagnostic tests for identifying underlying mechanisms is substantial. We aimed to advance the field with integrated technology for anorectal function assessment. Methods We developed a simulated stool named Fecobionics that integrates several tests to assess defecation pressures, dimensions, shape, orientation and bending during evacuation. A novelty is that pressures are measured in axial direction, i.e. in the direction of the trajectory. Using this novel tool, we present new analytical methods to calculate physiologically relevant parameters during expulsion in normal human subjects. Results Data are reported from 28 human subjects with progressively more advanced versions of Fecobionics. A new concept utilizes the rear-front pressure (preload-afterload) diagram for computation of novel defecation indices. Fecobionics obtained physiological data that cannot be obtained with current state-of-the-art technologies. Conclusion Fecobionics measures well known parameters such as expulsion time and pressures as well as new metrics including defecation indices. The study suggests that Fecobionics is effective in evaluation of key defecatory parameters and well positioned as an integrated technology for assessment of anorectal function and dysfunction.
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Affiliation(s)
- H. Gregersen
- California Medical Innovations Institute, San Diego, CA, United States
- Department of Surgery, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - D. Sun
- California Medical Innovations Institute, San Diego, CA, United States
- School of Microelectronics and Communication Engineering, Chongqing University, Shapingba, Chongqing 400044, China
| | - S.C. Chen
- Department of Surgery, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - W.W. Leung
- Department of Surgery, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - C. Wong
- Department of Surgery, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - T. Mak
- Department of Surgery, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - S. Ng
- Department of Surgery, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - K. Futaba
- Department of Surgery, The Chinese University of Hong Kong, Shatin, Hong Kong
| | | | - G.S. Kassab
- California Medical Innovations Institute, San Diego, CA, United States
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12
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Gregersen H, Chen SC, Leung WW, Wong C, Mak T, Ng S, Futaba K. Fecobionics Characterization of Patients With Fecal Incontinence. Clin Gastroenterol Hepatol 2021; 19:2447-2449. [PMID: 33127594 DOI: 10.1016/j.cgh.2020.10.043] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 10/17/2020] [Accepted: 10/21/2020] [Indexed: 02/07/2023]
Abstract
Fecal incontinence (FI) is characterized by involuntary loss of rectal content. Up to 9.5% of Americans younger than 70 years suffer from FI.1 The pathophysiology has many causes and is not well understood and diagnosed.
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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
| | - Kaori Futaba
- Department of Surgery, The Chinese University of Hong Kong, Shatin, Hong Kong
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13
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Kassab GS, Gregersen H, Sun D, Huang Z. Novel bionics developments in gastroenterology: fecobionics assessment of lower GI tract function. Physiol Meas 2021; 42. [PMID: 34190049 DOI: 10.1088/1361-6579/ac023c] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 05/17/2021] [Indexed: 11/12/2022]
Abstract
Biomechatronics (bionics) is an applied science that is interdisciplinary between biology and engineering (mechanical, electrical and electronics engineering). Biomechatronics covers a wide area and is probably best known in development of prosthetic limbs, vision aids, robotics and neuroscience. Although the gastrointestinal tract is difficult to study, it is particularly suited for a bionics approach as demonstrated by recent developments. Ingestible capsules that travel the tract and record physiological variables have been used in the clinic. Other examples include sacral nerve stimulators that seek to restore normal anorectal function. Recently, we developed a simulated stool termed fecobionics. It has the shape of normal stool and records a variety of parameters including pressures, bending (anorectal angle) and shape changes during colonic transit and defecation, i.e. it integrates several current tests. Fecobionics has been used to study defecation patterns in large animals as well as in humans (normal subjects and patient groups including patients with symptoms of obstructed defecation and fecal incontinence). Recently, it was applied in a canine colon model where it revealed patterns consistent with shallow waves originating from slow waves generated by the interstitial cells of Cajal. Furthermore, novel analysis such as the rear-front pressure (preload-afterload) diagram and quantification of defecation indices have been developed that enable mechanistic insight. This paper reviews the fecobionics technology and outlines perspectives for future applications.
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Affiliation(s)
- G S Kassab
- California Medical Innovations Institute, San Diego, CA, United States of America
| | - H Gregersen
- California Medical Innovations Institute, San Diego, CA, United States of America
| | - D Sun
- School of Microelectronics and Communication Engineering, Chongqing University, Chongqing, People's Republic of China
| | - Z Huang
- School of Microelectronics and Communication Engineering, Chongqing University, Chongqing, People's Republic of China
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14
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Scott SM, Simrén M, Farmer AD, Dinning PG, Carrington EV, Benninga MA, Burgell RE, Dimidi E, Fikree A, Ford AC, Fox M, Hoad CL, Knowles CH, Krogh K, Nugent K, Remes-Troche JM, Whelan K, Corsetti M. Chronic constipation in adults: Contemporary perspectives and clinical challenges. 1: Epidemiology, diagnosis, clinical associations, pathophysiology and investigation. Neurogastroenterol Motil 2021; 33:e14050. [PMID: 33263938 DOI: 10.1111/nmo.14050] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [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: 07/20/2020] [Revised: 10/12/2020] [Accepted: 11/06/2020] [Indexed: 12/16/2022]
Abstract
BACKGROUND Chronic constipation is a prevalent disorder that affects patients' quality of life and consumes resources in healthcare systems worldwide. In clinical practice, it is still considered a challenge as clinicians frequently are unsure as to which treatments to use and when. Over a decade ago, a Neurogastroenterology & Motility journal supplement devoted to the investigation and management of constipation was published (2009; 21 (Suppl.2)). This included seven articles, disseminating all themes covered during a preceding 2-day meeting held in London, entitled "Current perspectives in chronic constipation: a scientific and clinical symposium." In October 2018, the 3rd London Masterclass, entitled "Contemporary management of constipation" was held, again over 2 days. All faculty members were invited to author two new review articles, which represent a collective synthesis of talks presented and discussions held during this meeting. PURPOSE This article represents the first of these reviews, addressing epidemiology, diagnosis, clinical associations, pathophysiology, and investigation. Clearly, not all aspects of the condition can be covered in adequate detail; hence, there is a focus on particular "hot topics" and themes that are of contemporary interest. The second review addresses management of chronic constipation, covering behavioral, conservative, medical, and surgical therapies.
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Affiliation(s)
- S Mark Scott
- Centre for Neuroscience, Surgery & Trauma, Blizard Institute, Queen Mary University of London, London, UK
| | - Magnus Simrén
- Department of Internal Medicine & Clinical Nutrition, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.,Center for Functional GI and Motility Disorders, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Adam D Farmer
- Centre for Neuroscience, Surgery & Trauma, Blizard Institute, Queen Mary University of London, London, UK.,Institute of Applied Clinical Science, University of Keele, Keele, UK
| | - Philip G Dinning
- College of Medicine and Public Health, Flinders Medical Centre, Flinders University & Discipline of Gastroenterology, Adelaide, SA, Australia
| | - Emma V Carrington
- Centre for Neuroscience, Surgery & Trauma, Blizard Institute, Queen Mary University of London, London, UK.,Surgical Professorial Unit, St Vincent's University Hospital, Dublin, Ireland
| | - Marc A Benninga
- Department of Pediatric Gastroenterology, Hepatology and Nutrition, Emma Children's Hospital, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Rebecca E Burgell
- Department of Gastroenterology, Alfred Health and Monash University, Melbourne, Vic., Australia
| | - Eirini Dimidi
- Department of Nutritional Sciences, King's College London, London, UK
| | - Asma Fikree
- Centre for Neuroscience, Surgery & Trauma, Blizard Institute, Queen Mary University of London, London, UK.,Gastroenterology Department, Royal London Hospital, Barts Health NHS Trust, London, UK
| | - Alexander C Ford
- Leeds Institute of Medical Research at St. James's, Leeds Gastroenterology Institute, Leeds Teaching Hospitals Trust, University of Leeds, Leeds, UK
| | - Mark Fox
- Division of Gastroenterology and Hepatology, University Hospital Zürich, Zürich, Switzerland.,Digestive Function: Basel, Laboratory and Clinic for Motility Disorders and Functional Gastrointestinal Diseases, Centre for Integrative Gastroenterology, Klinik Arlesheim, Arlesheim, Switzerland
| | - Caroline L Hoad
- Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, UK.,NIHR Nottingham Biomedical Research Centre (BRC), Hospitals NHS Trust and the University of Nottingham, Nottingham University, Nottingham, UK
| | - Charles H Knowles
- Centre for Neuroscience, Surgery & Trauma, Blizard Institute, Queen Mary University of London, London, UK
| | - Klaus Krogh
- Department of Hepatology and Gastroenterology, Aarhus University Hospital, Aarhus, Denmark
| | - Karen Nugent
- Department of Surgery, Southampton University Hospital NHS Foundation Trust, Southampton, UK
| | - Jose Maria Remes-Troche
- Digestive Physiology and Motility Lab, Medical Biological Research Institute, Universidad Veracruzana, Veracruz, Mexico
| | - Kevin Whelan
- Department of Nutritional Sciences, King's College London, London, UK
| | - Maura Corsetti
- NIHR Nottingham Biomedical Research Centre (BRC), Hospitals NHS Trust and the University of Nottingham, Nottingham University, Nottingham, UK.,Nottingham Digestive Diseases Centre, School of Medicine, University of Nottingham, Nottingham, UK
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15
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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16
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Zhuang Z, Hung H, Chen S, Futaba K, Gregersen H. Translating Fecobionics Into a Technique That Addresses Clinical Needs for Objective Perineal Descent Measurements. Clin Transl Gastroenterol 2021; 12:e00342. [PMID: 33956418 PMCID: PMC8049154 DOI: 10.14309/ctg.0000000000000342] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 03/05/2021] [Indexed: 12/12/2022] Open
Abstract
INTRODUCTION Perineal descent is a phenomenon associated with anorectal dysfunction. It is diagnosed by defecography but subjected to manual measurements on the images/videos and interobserver bias. Fecobionics is a simulated feces for assessing important physiological parameters during defecation. Here, we translate Fecobionics into a new method for estimation of perineal descent based on electronic signals from the embedded inertial measurement units (IMUs). METHODS A displacement measurement method by a combined zero-velocity update and gravity compensation algorithm from IMUs was developed. The method was verified in a robot model, which mimicked perineal descent motion. RESULTS The method correlated well with the reference (R = 0.9789) and had a deviation from the peak displacement (range 0.25-2.5 cm) of -0.04 ± 0.498 cm. The method was further validated in 5 human experiments with comparison to the benchmark defecography technology (R = 0.79). DISCUSSION The proposed technology is objective, i.e., electronic measurements rather than by fluoroscopy or MRI. The development may impact clinical practice by providing a resource-saving and objective technology for diagnosing perineal descent in the many patients suffering from anorectal disorders. The technology may also be used in colon experiments with Fecobionics and for other gastrointestinal devices containing IMUs such as ingestible capsules like the Smartpill.
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Affiliation(s)
- Z. Zhuang
- Department of Surgery, the Chinese University of Hong Kong, Shatin, Hong Kong
| | - H.Y. Hung
- Department of Imaging and Interventional Radiology, the Chinese University of Hong Kong, Shatin, Hong Kong.
| | - S.C. Chen
- Department of Surgery, the Chinese University of Hong Kong, Shatin, Hong Kong
| | - K. Futaba
- Department of Surgery, the Chinese University of Hong Kong, Shatin, Hong Kong
| | - H. Gregersen
- Department of Surgery, the Chinese University of Hong Kong, Shatin, Hong Kong
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17
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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18
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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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19
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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20
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Gregersen H, Wang Y, Guo X, Field F, Nelson M, Combs W, Wang M, Kassab G. Simulated Colonic Feces Reveals Novel Contraction Patterns. Gastroenterology 2021; 160:660-662. [PMID: 33181140 PMCID: PMC10116159 DOI: 10.1053/j.gastro.2020.09.055] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 08/11/2020] [Accepted: 09/21/2020] [Indexed: 12/19/2022]
Affiliation(s)
- Hans Gregersen
- California Medical Innovations Institute, San Diego, California.
| | - Yanmin Wang
- California Medical Innovations Institute, San Diego, California
| | - Xiaomei Guo
- California Medical Innovations Institute, San Diego, California
| | | | | | | | - Mengjun Wang
- California Medical Innovations Institute, San Diego, California
| | - Ghassan Kassab
- California Medical Innovations Institute, San Diego, California
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Abstract
Biomechatronics (bionics) is an applied science that creates interdisciplinary bonds between biology and engineering. The lower gastrointestinal (GI) tract is difficult to study but has gained interest in recent decades from a bionics point of view. Ingestible capsules that record physiological variables during GI transit have been developed and used for detailed analysis of colon transit and motility. Recently, a simulated stool named Fecobionics was developed. It has the consistency and shape of normal stool. Fecobionics records a variety of parameters including pressures, bending, and shape changes. It has been used to study defecation patterns in large animals and humans, including patients with symptoms of obstructed defecation and fecal incontinence. Recently, it was applied in a canine colon model where it revealed patterns consistent with shallow waves originating from slow waves generated by the interstitial Cells of Cajal. Novel analysis such as the "rear-front" pressure diagram and quantification of defecation indices has been developed for Fecobionics. GI research has traditionally been based on experimental approaches. Mathematical modeling is a unique way to deal with the complexity. This paper describes the Fecobionics technology, related mechano-physiological modeling analyses, and outlines perspectives for future applications.
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Affiliation(s)
- Hans Gregersen
- The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China;
- California Medical Innovations Institute, San Diego, CA 92121, USA
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22
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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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