Ultrasonic measurement of rectal diameter and area in neurogenic bowel with spinal cord injury

How Can We Treat If We Do Not Measure: A Systematic Review of Neurogenic Bowel Objective Measures

Background

Guidelines fail to recommend objective measures to assist with treatment of neurogenic bowel dysfunction (NBD) in spinal cord injury (SCI).

Objectives

The main objective was to review the literature to identify the objective measures used in all NBD populations and to present their results and any correlations performed to validated subjective measures.

Methods

A systematic review of the literature was performed in accordance with PRISMA (2020) guidelines, including all records from January 2012 to May 2023 with MeSH terms like "neurogenic bowel" indexed in the following databases: PubMed, EMBASE, CINAHL, Cochrane Central Trials Register, and ClinicalTrials.gov. Abstracts were excluded if they did not include objective measures or if they only mentioned the esophagus, stomach, and/or small bowel. Records were screened independently by at least two collaborators, and differences were resolved by unanimous agreement.

Results

There were 1290 records identified pertaining to NBD. After duplicates were removed, the remaining records were screened for a total of 49 records. Forty-one records (82%) included subjective measures. Two-thirds of the articles involved the population with SCI/disease (n = 552) and one-third were non-SCI NBD (n = 476). Objective measures were categorized as (1) transit time, (2) anorectal physiology testing, and (3) miscellaneous. Of the 38 articles presenting results, only 16 (42%) performed correlations of objective measures to subjective measures.

Conclusion

There is an abundance of literature supporting the use of objective outcome measures for NBD in SCI. Strong correlations of subjective measures to objective outcome measures were generally lacking, supporting the need to use both measures to help with NBD management.

Research on biomechanical compatibility for a novel artificial anal sphincter with constant force

BACKGROUND

Existing artificial anal sphincter studies have shown that biomechanical compatibility problem between artificial anal sphincter and rectum caused by long-term morphological changes of the tissue surrounding the implanted prosthesis can lead to device failure or tissue ischemic necrosis. In this article, a mechanical artificial anal sphincter with constant force clamping is designed based on the superelasticity of shape memory alloys, which improved the biomechanical compatibility of implantable artificial anal sphincter.

METHODS

Firstly, the anatomical structure and the biomechanical properties of the rectum are analyzed to obtain the size parameters and material parameters of the rectal model. Secondly, a novel artificial anal sphincter with constant force is designed to improve the biomechanical compatibility between the artificial sphincter and the rectum. Thirdly, the static analysis of artificial anal sphincter is carried out by finite element analysis.

RESULTS

The simulation results show that the artificial anal sphincter can maintain a constant clamping force of 4 N within a certain variation range of intestinal tissue thickness, which verifies the constant force characteristic of the artificial anal sphincter. The constant clamping force of the artificial anal sphincter to the rectum is 4 N that is greater than the clamping force 3.99 N required to close the rectum, which verifies the effectiveness the artificial anal sphincter. The surface contact stress and the minimum principal stress of the rectum in the clamping state are less than the pressure threshold, which verifies the safety of the artificial anal sphincter.

CONCLUSIONS

The novel artificial anal sphincter has better biomechanical compatibility and improves the mechanical match between artificial sphincter and intestinal tissue. This study may provide more reasonable and effective simulation data for in vivo experiments of artificial anal sphincter in future, which may provide theoretical and technical support for further research about clinical application of artificial anal sphincter.

Preliminary study of a novel artificial anal sphincter with perception reconstruction

BACKGROUND

Artificial anal sphincter (AAS), as an advanced device, has been widely investigated by researchers around world. But the reliability of the structure is still unsatisfactory according to clinical results. What's more, the previous AAS systems are lack the ability of rectal perception as native anal sphincter, which fails to guarantee the safety of the blood supply. In addition, without it, the patient cannot determine when to defecate.

METHODS

In order to improve the reliability and safety of current AAS systems, a novel structure AAS system with rectal perception function, based on pressure sensor module, is proposed in this article. The novel AAS system has a closed three-arm clamping mechanism, with transmission structure of cam-follower system. Then, the design, strength check, optimization and force analysis of the proposed mechanism are investigated. After that, to remodel rectal perception function, the novel sensor module system based on strain gauge is established. Finally, in vitro experiments are conducted.

RESULTS

In vitro test, the sensor system could monitor the rectal pressure accurately. And when H = 24.6 cm (feeling the urge to have a bowel movement), the clamping pressure is 7.39 kPa. which is also less than the safe pressure 9.33 kPa.

CONCLUSIONS

Good performance of the reliability and safety of both novel rectal perception function and new clamping mechanism have been showed.

Bowel Dysfunction in Spinal Cord Injury

PURPOSE OF REVIEW

To evaluate and report current evidence regarding the management of bowel dysfunction in spinal cord injury. There is a paucity of high-quality large studies on which to base management advice.

RECENT FINDINGS

Recent research has focused on defining the nature of symptomatology of bowel dysfunction in SCI and describing the effects on quality of life and social interactions. Technical aspects of colonoscopy have received attention, and aspects of understanding the pathophysiology in relation to both neural and non-neural dysfunction have been studied. There has been refinement and expansion of the pharmacological and non-pharmacological treatment options for bowel dysfunction in SCI. Management of bowel dysfunction in SCI requires a comprehensive and individualized approach, encompassing lifestyle, toileting routine, stimulation, diet, medications, and surgery. Further high-quality research is required to inform best practice.