TILT ON THE TOILET

Team Members

Mentor

Dr. Richard E. Waugh, PhD, Biomedical Engineering, University of Rochester

Lucas Lassinger, CMTI Student, University of Rochester

Customer

Dr. Sara Salim, MD, Department of Physical Medicine and Rehabilitation, University of Rochester Medical Center

Problem Statement

Current posture modification devices that decrease duration of bowel movement are not suited for achieving and sustaining the squatting position for individuals with neurogenic bowel (NB).

Background & Customer Scenario

Neurogenic bowel dysfunction is a condition that affects individuals with severe neurological conditions, and it is defined as the loss of normal bowel function. For individuals with NB, performing a bowel movement can be a time consuming process and often requires a bowel program, which is an individualized and complete plan for NB patients that helps them accomplish a bowel movement. According to an interviewed caregiver of an individual with NB, the bowel movement may take up to 2-3 hours per session, and this session can occur typically 3-4 times per week (Stiens 1997, Caregiver VoC). This arises diverse physical, psychological and social effects, such as the time consuming nature of the procedure, the prolonged time spent sitting in one position which can lead to pressure ulcers, as well as limited control of their bowel movement. Posture modification devices are popularly used to reduce the duration and potential strain involved with performing a bowel movement, but most of these defecation posture modification devices target individuals with a full range of motion. Therefore, our goal is to create a posture modification device that allows an individual with NB to safely achieve a squatting position for the duration of the time it takes for them to perform a bowel movement.

The ideal patient we will consider for our design situation is an individual with a T12-level spinal injury, which falls under the category of ASIA A. This refers to somebody who has no motor or sensory function below the thoracic section of the spine, however maintains much of their upper trunk function, and can hold their posture upright for extended periods of time. We expect that by targeting the most severe injury classification, individuals with less severe injuries will be indirectly taken into consideration. Thus, a wide range of individuals with NB could benefit from our device.

Design Concept & Prototyping

Design specifications were developed with input from our research team team as well as our customer Dr. Salim. The VoC interviews with a caregiver and trainer of the bowel care process, NM, and OT specialists provided expertise into the metrics for these design specifications. The design specifications must comply with the standards: ANSI RESNA WC-1 and  ISO Standards 7176, and 17966. Our customers asked us to focus on creating a model complying with three critical quality requirements: (1) Posture Modification, (2) Patient Safety, and (3) Convenience.

Our device consists on a torso-lean attachment meant to be connected to the HomCom Commode Chair(HomCom Personal Mobility Assist Waterproof Commode Shower Wheelchair Self-Transport Cart, 2022). The device development was divided into three subsystems: (1) User to Device Interface, (2) Posture Modification, and (3) Device to Environment Interface.

The device is composed as follows:

• (1) There are two vertical bars, one on each side of the commode, with adjustable dimensions that will be attached to the commode via clamps. 

• (2) These adjustable bars then attach to a bar fitting socket, which allows the user insert and remove the support bar in order to accomplish transfers and clearance of the device.

• (3) The fit socket is then attached to another set of bars with adjustable dimensions. This set of adjustable dimensions allows the user to move the cushion closer/further away, and thus move the cushion higher/lower on the user’s torso. 
  
• (4) A single horizontal support bar connects the bars, allowing more structural stability for more interface to connect with the cushion.
  
• (5) The horizontal support bar interfaces with a cushioned chest support connected by U-clamps which will interface with the user’s torso.

• (6) Anti-tipping bar is a rotatable clearance mechanism that interfaces with the bottom commode bar via a T-connector clamp to account for user safety and provide additional stability.

Final Prototype

Testing & Results Assessment

Our design process began with mechanical testing of attachment and interface materials to select secure attachment mechanisms, and determine which materials had mechanical properties most appropriate for compatibility with the HomCom commode chair as well as durability for sustaining the user and its intended medical use. After testing several materials and methods, we were able to finalize material selection and create more prototypes with the aim of reflecting a realistic feel of the torso-lean device overall. Through multiple in-person and virtual meetings with our customers, we were able to evaluate our prototype and receive helpful feedback. 

To quantify whether our torso-lean device could accomplish completion of the key aims we focused on, we performed a series of tests, as described below.

Future Directions

Our device is currently at a stage in which further simplifications can be made. First, the 60 degree bent bar generating the 22.5-35 degree hip flexion angle could be made into a single bar piece (fully eliminating the angle plate) to reduce the risk of skin tears as well as manufacturing costs. Second, limitations of arm movement and reach for individuals with broad shoulders can be addressed by lowering the horizontal bar and incorporating a slide board mechanism for the torso cushion. As for testing, the support user weight testing plan would ideally be repeated to ensure that the clamps prevent moments from occurring or assessing the need for incorporating additional bars interacting with the floor and acting as counterweight to prevent the rotation. Furthermore, we would like to conduct other testing plans that were unable to be done, such as humidity and moisture resistance testing, as well as temperature testing. Another design change that may be implemented in the future is the incorporation of the anti-tipper attachment, and a forehead rest.

Our team has participated in a couple of business/design competitions. Throughout our conversations with our advisor, we have considered business planning with regards to design/utility patents. This is something that has remained as an open conversation, but we are first focusing on simplifying our design. Next steps also include clinical testing as briefly discussed with our customer. The concept challenge was brought to us with an intuition that the squatting position is also capable of assisting individuals with spinal cord injuries to produce an easier bowel movement. However, this step may solely be organized by our customer or her colleagues at URMC.

Acknowledgements