Bath Chair for a Boy with TAR Syndrome

Robert Buechler, Aaron Carlson, Lenny Slutsky
Duke University
Durham, NC 27708


It is difficult for our client, an 8-year-old boy with Thrombocytopenia Absent Radius (TAR) Syndrome, to bathe independently because his arms are very short. To assist him, we built a bath chair using furniture grade PVC for the frame, HDPE for the seat, and mesh bath sponges as washing surfaces. A shower caddy was mounted to a safety railing on the right side of the chair, and shower heads were attached to the top of the chair and to a safety railing on the left side. The water flow for each shower head can be controlled by the client using two push-button valves on a diverter. Using the chair, the client can now bathe independently.


Bath Chair; TAR syndrome; Assistive device; Adjustable Shower Heads; PVC pipe


This photo shows the prototype for the bath chair. The prototype differs from the final product in the following ways. The back of the chair is a curved piece of thermoplastic, and the seat is made of plywood. Only one bath sponge is mounted on the top rail for head-washing, and only two bath sponges are mounted on the back post for back-washing. In addition, there is no soap dish accompanying the shower caddy.  Photo 1: Chair Prototype (Click for larger view)

Our client is an eight-year-old boy who has Thrombocytopenia, Absent Radius syndrome, or TAR syndrome. TAR syndrome is a rare genetic disorder characterized by low platelet levels in the blood and the absence of radii. The ulna and humerus are also sometimes absent or poorly developed (1). As a result, our client’s arms are short and weak. His thumbs also have a limited range of motion, so he has difficulty grasping most items. In addition, his legs, though very strong, have a limited range of motion.

This photo shows the back of the bath chair. There are three vertical supports, which are connected by a rail on top and a crossbar approximately 8” above the seat. This photo shows the base of the chair from a front view. The base has two layers, which are connected at all 4 corners and in the middle of the back of the chair. There is a crossbar running from front to back on the top layer to provide more support for the seat, which is screwed into the top layer. These two photos show the safety rails on the bath chair. The right safety rail (left photo) has two forty-five degree bends and has the bath brush holder, soap dish, and shower caddy attached to it. The left safety rail (right photo) has one ninety-degree bend and has a scrub brush and diverter mounted on it. Both safety rails start at the back of the chair and connect to the seat. They are made from 1” PVC. Photo 2: (a) Chair back, (b) Chair base, (c) Safety Railings (Click for larger views)

The physical disabilities of our client sometimes make it difficult or impossible for him to perform certain actions independently. One such task that he has struggled with is bathing, as he is unable to reach many parts of his body (top of his head, stomach, back, backside). In addition, he cannot apply sufficient strength to clean many of the areas that he can reach. As a result, our client has needed his parents’ help to bathe, but he would like to be able to bathe himself. To do this, he needs a chair that will give him stability and safety while washing, while allowing him to reach and clean all parts of his body.

Many bath chairs are commercially available, but due to the rarity of our client’s disability, none of these chairs meet his specific needs.


This project’s goal was to design and develop a chair that allows our client to clean all areas of his body easily, comfortably, safely and independently


Photo “a” shows the showerhead that is attached the to the left safety rail. Photo “b” shows the showerhead that is attached to the top rail. Both showerheads are connected to the rails by 3-way tees. The showerheads are attached to hoses that fit into rotating showerhead mounts. Handles were built from PVC pipe that connect to the showerhead so that the client can adjust the direction of the flow of water. Photo 3: (a) Top showerhead attachment (b) Side showerhead attachment (Click for larger view)

We designed the Bath Chair to cater to our client’s strengths. He has a limited range of motion in one of his legs and both of his thumbs, and also has short, weak arms. However, he has strong legs and is very flexible around the hips. As a result, we designed the chair so that he cleans himself mainly by rubbing against mesh bath sponges that are attached to the chair, thereby minimizing the use of his hands.

Our preliminary design (Photo 1), used for client testing, was very similar to the final product, but used plumbing-grade PVC pipe for the frame and plywood for the seat.

This photo shows the diverter mounted on the left safety rail. It splits the water flow from the faucet into the two showerheads. The flow can be controlled by using two push-button valves on the diverter.  Photo 4: Diverter (Click for larger view)

At one of the first meetings with our client, we discovered that he could rub his back more effectively against a curved surface than against a flat one. As a result, our prototype had a thermoplastic curved back with a washcloth attached to it. However, this did not work as we had hoped, and we found that our client preferred rubbing against bath sponges mounted directly onto the back of the chair.

This photo shows the seat of the chair. The seat is a 24” X 24” piece of HDPE that was cut to fit around the safety railings and back posts. The edges of the seat are routed for a smooth contour. A non-slip mat covers the central area of the seat to provide a comfortable and non-slip surface to sit on.  Photo 5 Here: HDPE seat with non-slip mat (Click for larger view)

After testing the prototype, we slightly changed the design of the frame to accommodate a flat back. The back of the frame (Photo 2a) now consists of three vertical bars that are connected by the top rail and a crossbar. The latter prevents our client from falling out the back of the chair if he should slip. The frame of the chair is made from 1.5” furniture-grade PVC pipe. The base (Photo 2b) is rectangular and has two layers. The bottom layer is for structural support, and the top layer, which contains an extra horizontal crossbar, is where the seat rests. The chair has safety rails on each side of the seat (Photo 2c), made from 1” PVC pipe, since this thickness is easier for our client to grasp. The safety railings are at a height such that our client can easily grab onto them if necessary.

This picture shows the shower caddy and soap dish mounted to the right safety railing through an acrylic backing. The shower caddy has two partitions – one can hold the client’s soap and shampoo bottles, while the smaller section can hold the client’s rinsing cup. A soap dish is located next to the shower caddy so that our client only needs to dispense soap once. Photo 6 Here: Shower caddy and soap dish (Click for larger view)

Two showerheads are mounted to the frame of the chair, one at the top of the seat back and one on the left safety railing (Photo 3). A hose is attached to the tub faucet via a threaded fitting. This hose is connected to a diverter (Photo 4), to which hoses for each of the two showerheads are attached. Each showerhead is attached to the frame with 1” PVC pipe and is mounted on a rotating showerhead mount. A handle made from 0.75” PVC pipe is attached to the rotating mount. The end of each handle is a ½” 3-way PVC tee which our client can grasp to control the direction of water flow. The diverter also has an on/off switch for each branch, which allows our client to control the water supply to each showerhead.

This picture shows all of the bath sponges attached to the chair that our client will use to wash himself. Our client will use the two bath sponges on the top rail of the chair back to wash his head. He will use the three bath sponges on the middle post of the chair back to scrub his back, and the bath sponge on the seat will help clean the client’s backside and between his legs. Photo 7: Bath sponges attached to the chair for washing (Click for larger view)

The seat (Photo 5) is made from 0.5” thick High Density Polyethylene (HDPE), routed smooth on the edges. It rests on the base of the chair and is secured to the frame with machine screws. The top of the seat is covered with a ComfortArt™ Plus Non-Slip Bath and Shower Mat, by Griptex, which gives the seat a comfortable, non-slip surface. Small holes were drilled through the seat to prevent pooling of water.

An acrylic sheet is attached to the right safety railing to provide a convenient location for bathing accessories. A shower caddy (Photo 6), which holds soap, shampoo, and a cup that our client uses for rinsing, is mounted to the acrylic sheet, along with a soap dish. The soap dish allows our client to dispense soap only once, instead of having to pick up the bottle each time he needs more soap.

This picture shows the method by which the bath sponges are attached to the chair. The system is similar to how a manila envelope is closed. Two small, circular plastic pieces are riveted to a larger, ovular plastic backing at opposite ends of the backing. The backing is oriented such that the longer side is horizontal, and it is bolted to the PVC pipe. The strings from the bath sponge are then threaded through holes drilled in the pipe and wrapped around the circular pieces in the gap between the circular pieces and the backing. This keeps the bath sponges securely attached but allows them to be removed and replaced easily. Photo 8: Envelope clasp attachment system (Click for larger view)

We designed specific ways for our client to wash areas he couldn’t reach previously: his head, hands, stomach, back, backside, groin area, and upper legs. Bath sponges are attached to the frame of the chair in different places to allow our client to wash his head, back, backside, and groin area. We originally designed long-handled brushes, both straight and curved, for the client to use to wash his head, but these were either too heavy or too difficult to position properly. As a result, we attached two bath sponges to the top bar for our client’s head, along with three attached to the middle vertical bar on the back for our client’s back, and one attached to the seat for our client’s groin area and backside (Photo 7). Each bath sponge is attached to the frame of the chair using a separate attachment system. Each attachment system (Photo 8) consists of an ovular acrylic sheet that has two acrylic circles attached to one side using rivets. The result is similar to the clasp of a manila envelope and holds the bath sponge tightly. This system gives the bath sponges the dual properties of being very secure while being easy to replace.

This group of photos shows the bath brush, which is made from the handle of a 22.5” Sammons Preston Rolyan® Long Scrub Brush. A bath sponge was attached to the top of the handle (left panel) using the envelope clasp attachment system shown in Photo 8. An acrylic stopper was added to the handle approximately a third of the way from the top to prevent the brush from slipping out of our client’s hands. This stopper can be seen in the center panel, which shows the entire brush. The bath brush can be stored in a holder on the right safety rail for easy access when he is not using it (right panel).

Photo 9: Bath Brush (Click for larger view)

Our client will wash his stomach and the tops of his legs with a long-handled bath brush (Photo 9). It consists of the handle from a 22.5” Sammons Preston Rolyan® Long Scrub Brush with a bath sponge attached to the end (secured using our attachment system). An acrylic stopper is mounted to the handle to allow our client to grasp the brush without his hand slipping. The brush is stored in a holster on the right safety rail. A finger scrub brush (Photo 10) is also mounted to the left safety railing, just above the diverter, to allow our client to wash his fingertips.


This photo shows the finger scrub brush. This brush, purchased from, is mounted above the diverter on the corner of the left safety rail. This allows our client to clean the tips of his fingers and his fingernails. Photo 10: Finger Scrub Brush (Click for larger view)

We discussed all ideas amongst ourselves and with our client and his mother before any building began. A significant amount of time was spent in this stage. We then built prototypes, and our client tested them while wearing a bathing suit in his bathtub. Adjustments were made based on our client’s feedback and the prototypes were re-evaluated, until the client was happy with that component of the device. This strategy allowed us to build a device that our client enjoys and will be able to use effectively.


A major advantage of the Bath Chair is that it has few moving parts, and these parts are very simple. This makes the chair both easier to use and more likely to last for a long time. In addition, our client has complete control over the water flow. He can use the push-button valves to turn either showerhead on or off, and he can reach the faucet knobs with his feet to adjust the temperature of the water while safely seated in the chair.

The one significant limitation of our chair is that the height of the chair is not easily adjustable. This was unavoidable because the locations of components such as the bath sponges and safety railings forced a certain structure for the PVC pipe and fittings. However, the client’s father can remove and replace the top rail of the frame and add longer pieces of pipe to make it higher when necessary.


  1. Greenhalgh et al. “Thrombocytopenia-absent radius syndrome: A Clinical Genetic Study.” Journal of Medical Genetics. 2002(39): 876-881.


This project is supported by the National Science Foundation under Grant No. BES-0610534. We would like to thank our professor, Dr. Laurence Bohs, for guiding the project design and development, and Gabriel Howles, for helping machine parts and giving great input on the design of the device.

Primary Author: Robert Buechler, 18 Alberta Drive, Marlboro, NJ 07746




This photo shows our client using the bath sponges on the top rail of the chair to wash his hair. He can reach the sponges with his hand to apply shampoo to them, and then he rubs his head against the sponges to wash his hair. This eliminates the need for him to use his hands to wash his hair directly. Photo A1: Client Washing Head (Click for larger view)
This photo shows our client using the bath brush to wash some areas of his torso that are particularly difficult for him to reach without assistance. He holds the brush comfortably underneath the stopper and can guide it to whatever area he needs to wash. Photo A2: Client Using Bath Brush (Click for larger view)

This bath chair will have an immediate impact on our client’s life. He has been trying to bathe on his own for six years without success, so using this chair to bathe independently should provide him with a huge confidence boost. The significance of this device can be seen in the reactions of both our client and his mother; as his mother says, “This is a huge step in terms of personal care for himself. He is so excited about getting it that he is counting the days to final delivery… I can't put into words the joy it makes me feel seeing him excited about gaining this independence.” Photo A1 and A2 show the final product in use.




The lower layer of the base is made from 1½” PVC pipe and fittings. Parallel sides of the layer were put together and then attached all at once using PVC cement. The lower layer has 4 legs which rest on the floor and are capped with outer end caps to protect the pipe of the chair.

Figure B1: Lower Layer of Base


The second layer of the base is much the same as the first except it has a crossbar spanning the middle from front to back to give extra support to the seat. When the second layer is completely built, it is glued to the lower layer all at once.


Figure B2: Top Layer of Base


The third layer consists of the back of the chair. It has three vertical pipes with a horizontal crossbar for stability and to prevent the client from falling off the chair if he should slip. There is also an angled 3-way tee on the top rail for the top showerhead. Bath sponges are attached to the middle vertical pipe and to the top horizontal pipe to allow our client to wash his back and head respectively. This layer is attached to the base after it is completely built and after the HDPE seat is attached to the base.

Figure B3: Schematic of Back, Front View

The right safety railing is made from 1” PVC pipe and consists of two 45˚ elbows and one coupling. The backing for the shower caddy and soap dish is attached to this railing, using the coupling for stability. The safety railing is glued to the base and back of the seat before the shower caddy backing is attached.

Figure B4: Right Safety Railing

The left safety railing is made from 1” PVC pipe and consists of a 90˚ elbow and an angled 3-way tee that the showerhead mount attaches to. A hand scrub brush and the diverter to switch between showerheads are also attached directly to this railing. This railing is glued to the base and back of the chair before the attachments are secured.

Figure B5: Left Safety Railing

Two circular plastic discs are riveted through their center to opposite ends of a third piece of plastic. The resulting device is used to secure the bath sponges to the chair. Similar to a manila envelope clasp, the strings on the bath sponge are wrapped around the gap between each disc, providing a secure hold. This also makes the bath sponges easy to replace.

Figure B6: Schematic for Envelope Attachment System


Likelihood of Occurrence: Frequent, Probable, Occasional, Remote, Improbable, Incredible

Severity of Consequence: Catastrophic, Critical, Marginal, Negligible

Risk Assessment: Intolerable Risk, Undesirable Risk, Tolerable Risk, Negligible Risk

Potential Hazard Likelihood Severity of Consequence Risk Assessment Plan
Falling off of chair Remote Marginal Tolerable Safety railings, textured seat.
Slipping while on chair Occasional Marginal Tolerable Safety railings, non-slip pad on seat, no sharp edges, cap nuts on all exposed screws.
Chair tipping over Improbable Critical Tolerable Chair is heavy and has a low center of gravity.
Water or soap in eyes Probable Negligible Tolerable Attach hook to frame to hold a dry washcloth for drying eyes.
Burning from hot water Remote Marginal Tolerable Heat limiter already in place to restrict water temperature.
Chair collapsing Improbable Critical Tolerable Pipes are connected with PVC cement, which permanently bonds the frame.
Hitting chair attachments Probable Negligible Tolerable Attachments are placed along the chair frame and are out of the way.
Chair slipping Remote Negligible Negligible Rubber on feet of chair, combined with weight of chair, should prevent slipping.
HDPE breaking Improbable Marginal Negligible HDPE is very strong and meant to last for a long time; crossbar underneath seat adds support.
Attachments breaking Remote Negligible Negligible Attachments are securely connected to chair frame with bolts, rather than adhesives.
Drowning Incredible Critical Negligible Tub drain should always be open so water should never accumulate at the bottom of the tub.