Choosing the right seat on a commode chair

Many users will benefit from tilt-in-space, an action where the seat and backrest of the chair can be tilted rearwards as one whole unit.

This provides massive benefits for those users who lack the ability to control their own posture, those who fatigue easily when sitting upright for any length of time.

Whatever the frame and function of the commode, the seat is often the one part which impacts the most on its success as an aid to daily living.

In order to perform in the toilet the user needs to feel comfortable, supported and safe. Only then can the muscles relax for the toilet function to proceed. Here I suggest 5 questions you can ask when choosing your commode seat:

1. Is the seat comfortable?
2. Is the aperture the correct size?
3. Is the aperture in the right location?
4. Is there sufficient space for personal hygiene?
5. Does the seat protect against tissue injury?

1. Is the seat comfortable?

Often we observe commode seats that are produced in such a way that minimises the cost of manufacture. This has the effect of producing a product which is acceptable to those with limited budget. However this is often counterproductive: with little effort or attention paid to the design of the seat, the result is often a surface which is rigid, has little profile and pays little attention to the demands of the user. The result is firstly discomfort, and often leads quickly to clinical detriment. Many of the users we see suffer from the loss of sensation. This makes it difficult for the user to give feedback on how the seat feels beneath them. This can result in the chair being used for long periods of time with little or no observation that the seat is causing discomfort or pain. Good quality foams are essential to provide the first layer of comfort. Shaping within the seat is also a major contributor to the comfort of the seat – a seat which reflects the shape of the pelvis and provides envelopment of the bony parts of the pelvis is essential in ensuring the occupant is comfortable and therefore relaxed; relaxation is, after all, what we desire when on the toilet!

2. Is the aperture the correct size?

One of the defining features of a commode seat is that it has an aperture underneath the user. Whilst essential for effective operation, this aperture gives cause for concern, not least because when our user is seated it’s the hardest part of the seat to evaluate.

Looking at an adult pelvis from a structural point of view, it’s anthropometrically proven that the dimensions fall within some fairly narrow parameters. A female pelvis is distinct from a male pelvis, but the distances between the ischial tuberosities are found in an observable pattern of similarity, despite the appearance of users varying drastically. In essence, whilst we observe that many assessments result in a seat being provided which reflects the visual appearance of the users hips, (ie, a lean person would often be given a small aperture, and vice versa, a larger person a large aperture) the reality is that under the visible ‘draping’ the pelvis remains pretty much the same in dimension.

When it comes to stabilising posture, it is well recognised that we need to start with paying the pelvis some serious attention. If a pelvis of a certain width is balanced on a seat with a narrow aperture underneath, it stands to reason that the ischial tuberosities (our balancing bones) will be sitting directly on the seat top each side of the aperture. The narrower the aperture, the more accurately we will need to place our user so that the aperture is aligned with the ‘centre of action’!

If the same pelvis is sat on a seat with a wide aperture then we often observe ‘coning’; the pelvis drops through the aperture with the flesh of the buttocks being the only thing stopping a complete disaster. This can result in some unwelcome pinching and compression, and can make it difficult for the user to clean themselves effectively.

The ultimate seat has a shaped surface which cradles the pelvis, whilst the aperture in the seat is of a width which provides support and feedback for the sitting bones whilst cradling the flesh of the buttocks.

3. Is the aperture in the correct location?

People sit in different ways – that much is clear just from simple observation. And those of us who can sit unaided will sit autonomously – that is, without giving it a huge amount of thought. Small shifts, twists, rotations, crossing and uncrossing legs all happen subconsciously, fine-tuning our pressure points, relieving any discomfort. And all this without much or any conscious input.

Consider then those who are unable to do this movement without assistance. They need to be positioned in specific ways, carefully supported so they can function in the most effective way. This results in postures which are acquired and over time become seen as ‘normal’ for the particular person. One of the most common of these acquired postures would be the posterior pelvic tilt or the ‘sacral sit’. For those who have limited core strength in their trunk, maybe having lost the use of the major leg muscles, but still are able to move their upper body, this position involves the rotation of the lower part of the pelvis forward. Often associated with a kyphotic spine, the coccyx is tucked under the pelvis and results in the user sitting ‘behind’ the pelvis ie all the weight supported on the spinal column is now anterior to the ischial tuberosities. Whilst this is an abnormal posture, many who have this acquired posture would consider it a position where they can find a more stable position in the chair, either for self-propelling or for daily activities.

Most commode chairs have an aperture which is smaller and a different shape to that found on a regular WC. Sitting on a commode chair is an altogether different experience. Assuming this abnormal sacral position on a regular toilet seat may not have drastic consequences as the space inside the aperture is so large. However in the case of a commode seat, with an aperture which has been designed to closely support the pelvis and give massive support to the whole posture, tilting the pelvis in a posterior rotation will move the ischial tuberosities towards the front of the aperture. The results of this are two-fold: 1. The ITs now rub up against the narrowing width of the front of the aperture with a potential for tissue damage and 2. The epicentre of action is now far forward of the centre of the aperture and again compression is likely, making a successful toilet highly unlikely.

Consider the option of being able to move the aperture underneath a user, rearwards to support a user who can sit with a neutral pelvic position, and forwards to position the aperture correctly for someone who sit in an abnormal pelvic position. A simple innovation but one that has the best interests of the user at its heart.

4. Is there sufficient space for personal hygiene?

Whilst not every user has the ability or the aspiration to clean themselves, it’s a basic right of every user to leave the bathroom clean and fresh. Providing the space and environment for this to occur is the remit of the seat of the commode chair (as well as often depending on the design of the chassis). Access for hands through the front of the aperture is as important as being able to reach in from the side of the chair.

Seat design is critical in giving the user and their assistants’ adequate access for cleaning. Being given the option to have a side access seat (where the seat aperture opens to the left or right instead of the front) is often a boon for those who need maximum access for more tricky operations such as bowel irrigation or medication routines.

Rear access seats (where the aperture opens to the rear) are also particularly helpful where the carers have specific requirements or where suspension of the coccyx is sought after.

5. Does the seat provide adequate protection against tissue injury?

For those of us blessed with healthy tissues, sitting for 45 minutes on an unforgiving surface maybe only slightly irritating but mitigated by the knowledge that given a few minutes of walking around the tingling will have disappeared and the experience will have been forgotten.

It stands to reason that we should pay considerable attention to the fact that sitting for a very short while can result in tissue marking, redness and at the worst a pressure injury. It is proposed that within a very short space of time, tissue death can occur as a result of cellular deformation.

Often we will see users where concern is raised that despite paying for a high-end pressure cushion for use in the day-time wheelchair, the user has sustained a pressure injury. 10 hours a day on that expensive cushion and we cant understand why a pressure sore has broken out…until we look at the commode chair where our user spends just 15-20 minutes every day and observe that the seat is providing next to no protection for soft tissue. In that short period every day, we can undo a tremendous amount of positive work that has been achieved in every other seat.

Whilst pressure mapping every user for their commode seat may be an unpractical suggestion, from clinical research we can see the significant difference between a regular seat which has been constructed in a cost-efficient manner by the accounts department, and a specialist seat which has had lavish attention to every detail by practitioners who appreciate the benefits it will bring everybody that comes into contact with it.

Consider the surface profiling which allows the envelopment of the pelvic bones, a soft base foam which provides feedback, a visco-elastic foam providing cushioning to the ischial tuberosity’s and a bi-elastic vinyl upholstery which will stretch to allow those bones to sink into the foam. All these features which provide an environment which protects and supports the vulnerable skin and tissue of a user.

This image illustrates the features of the RAZ moulded seat cushion, a popular choice for any user who needs positioning, pressure relief and comfort.

Conclusion

These 5 questions are in no way the only questions that we should ask when specifying a commode chair. Every assessment will need to consider the specific requirements of the individual, but I believe that this list may help engender some deeper thinking about the outcomes of the choices that you make.

Over my career I’ve encountered dozens (maybe hundreds) of situations where a specifier suggests that whilst their client is lying on an air mattress of a night time, and on a high-end cushion in their wheelchair, that a simple commode is satisfactory as they ‘only have to sit on it for 15 minutes a day’.

We need to pay more attention to the positive impact a commode chair can have on a user’s wellbeing when chosen with an eye on the right questions.

What do you think? I’d be delighted to have your comments or observations on this discussion.