DESIGN DEVELOPMENT OF A NEW MANUAL PRONE CART

Mark Cors, BFA, Pascal Malassign, MID, IDSA; Sam Schnurr, Rosemary Bonifay, MSW; Audrey L. Nelson, RN, Ph.D.; todd Hoehn, BFA and Robert Meurer, BFA.

Milwaukee Institute of Art & Design (MIAD), Clement J. Zablocki VAMC, Milwaukee WI. Medical College of Wisconsin, Milwaukee, WI.; James A. Haley VAMC, Tampa, FL.

ABSTRACT

Individuals with SCI who use a prone cart for mobility, have identified significant problems with current models. Specifically, prone carts interfere with activities of daily living (ADL) and with socialization. In addition prone carts lack adequate body support for comfort and safety.

The impetus for a new design came from Mr. Schnurr, a service connected veteran with SCI. He formulated the idea of a prone cart with an articulated body support to improve comfort and safety. His idea was given to a team of Industrial Design students at MIAD in 1992 with the task of turning it into a product.

Three years later, and several prototypes designed and evaluated along the way, a new manual prone cart is now ready for commer-cialization. The new prone cart features an angle adjustable torso support; a foam contoured body support; a padded front deck with drink holder, for eating, writing and elbow supports and front pull-out storage drawer.

BACKGROUND

Prone carts are used for mobility by individuals with SCI, bedridden for months at a time because of pressure ulcers. Individuals with SCI are at high risk for developing pressure ulcers. Once a pressure sore develops, the patient must stay off affected areas until they are healed, in most instances, precluding the use of a wheelchair. Prone carts provide an alternative to prolonged bed immobilization for patients with ischial or sacral pressure ulcers who must lay on the side or in prone position.

Because of their crude design, and the lack adequate body support for comfort and safety the typical prone carts found around the SCI Center prevent their users to perform simple activities of daily living (ADL). For example it is impossible to eat, write or work from the prone cart. In addition it is extremely difficult to go up or down ramps, go into elevators, into a cafeteria or a store on a prone cart.

STATEMENT OF THE PROBLEM

The development of a new manual prone cart designed to improve the quality of life of patients with pressure ulcers and who use a cart for mobility, was a compelling need.

RATIONALE

The idea for a new design came from a veteran, Mr. Schnurr, who has lived on a prone cart for more than 15 years and from his caregivers at the Milwaukee VA SCI Center. In an attempt to solve the problems associated with living on his old horizontal prone cart, Mr. Schnurr formulated the design for an angled cart. His idea was that by laying down at an angle one could look-up in a comfortable and painless position. Before Mr. Schnurr was in constant back pain from the elevated dorsal position he was assuming on his old horizontal prone cart.

DESIGN and DEVELOPMENT

A team of MIAD senior Industrial Design students was assigned to take Mr. Schnurr' idea with the task of turning it into a product. Working in collaboration with Mr. Schnurr, MIAD faculty and VA SCI clinicians, the stu-dents developed concept drawings, and made a 1/4 scale model of a new prone cart. In recognition for this innovative design, an Award of Industrial Design Excellence was presented in 1993, by the Industrial Designers Society of America (IDSA).

From the award winning design and the scale model made by the students, a MIAD design team was involved for the following 18 months to refine the design and fabricate three full size carbon fiber prone carts prototypes. Named the SAMMY LS's these prone carts were made at MIAD with sponsorship from PVA and EPVA.

The SAMMY LS

The SAMMY LS features: (1) articulated and angle adjustable torso/leg support activated with manually operated hydraulic pumps; (2) contoured bed design; (3) elbow rest; (4) front deck with beverage holder for eating/working; (5) a side pull-out storage drawer; and (6) rear bed extensions with feet protector. Dimensions: Length: 142 cm (55.90") Height: 89 cm (35") Wheel to wheel width: 65 cm (25.6") Wheel base: 95 cm (37.4")

Propulsion: Manual with two composite 61.5 cm (24") front wheels with hand rings and two 12.5 cm (5") swivel casters in the back.

Evaluation: In addition to Mr. Schnurr who has lived on the first SAMMY LS since 1993, the other "SAMMY LS" prone carts have been in use at the Milwaukee and Tampa VAMC's since that time. Based upon users feed back, the following assessment has been made:

The SAMMY LS is ideally suited for AKA (above knee double amputees, children or short individuals (5 to 25% percentile) and its short wheel base provides easy access to a van equipped with a wheelchair lift.

Positive features: overall bold design, arti-culated torso support with manually operated hydraulic pumps to vary the angle, contoured bed design, the elbow rest, front deck with beverage holder and for eating /working, height ideally suited for access to public phone, counter tops, etc.

Negative features: when used with the rear extensions, the cart is more difficult to propel because of weight displacement to the rear; the bed support when angled down give users the sensation of sliding off the cart; the side drawer is difficult to reach and use.

The SAMMY LS's The SCI-PC 22 prone cart

Based upon the evaluation results of the SAMMY LS, another design was undertaken and named the SCI-PC22. Fabricated in 1994 in collaboration with ORTHO-KINETICS, it has a 2.5 cm square steel frame construction to cut the high cost of carbon fiber.

The features of the SCI-PC22 manual prone cart include: (1) angle adjustable torso and leg/bed support, (2) padded front deck with drink holder, for eating, writing and elbow supports, (3) a front pull-out storage drawer, (4) contoured bed design with 5 cm thick naugahyde vinyl covered urethane foam.

Dimensions: Length: 178 cm (70") Height: 78.75 cm (31") Wheel to wheel width: 58.5 cm (27") Wheel base: 104 cm (41")

Propulsion: Manual with two composite 61 cm (24") front wheels with hand rings and two 20 cm (8") swivel casters in the back.

Evaluation: Based upon user feed back at the Milwaukee and Tampa VAMC's the following assessment of the SCI-PC 22 has been made:

Positive features: overall length; ease of mobility; improved weight distribution; articul-ated torso support; padded front deck with beverage holder and for eating/working; contoured bed design, elbow rests; height ideally suited for access to public phone, tables, counter tops, etc.

Negative features: the length prevents access to van wheelchair lift, the leg support when angled down give users the sensation of sliding off the cart and no area for urine and/or osmotic bags is provided.

The SCI-PC 22 prone cart The SCI-PC 23 prone cart

Based upon the evaluation results of the SCI-PC 22, refinements of the design were made for fabrication with 3.80 cm (1.5") steel tubing.

The features of the SCI-PC 23 manual prone cart include: (1) angled adjustable torso support, (2) padded front deck with drink holder, for eating, writing and elbow supports, (3) a front pull-out storage drawer, (4) contoured bed design with 5 cm thick naugahyde vinyl covered urethane foam, (5) a removable section for urine and/or osmotic bags, (6) a frame that forms an all around protective bumper and a foot guard.

Dimensions: Length: 190.5 cm (75") Height: 76.4 cm (30") Wheel to wheel width: 75 cm (29.5") Wheel base: 106 cm (42")

Propulsion: Manual with two composite 61 cm (24") front wheels with hand rings and two 20 cm (8") swivel casters in the back.

The SCI-PC 23 prone cart

DISCUSSION

This project clearly illustrated that a team effort between users, clinicians, designers and a manufacturer, all involved in solving a much needed mobility patient need can lead to the successful design of a new product.

The outcome of this team effort is that first two SCI-PC 23 prone carts were ordered in the fall of 1995 to Ortho-Kinetics by the SCI Center at the Milwaukee VAMC.

Prone carts in use at VAMC

ACKNOWLEDGMENTS

Funding for this project was provided by EPVA, (Eastern Paralyzed Veterans Association), PVA, (Paralyzed Veterans of America), Wisconsin PVA, Mr. Schnurr, VA Rehabilitation R&D Service, and NIDRR, (National Institute of Disability and Rehabilitation Research). In addition the authors wish to sincerely thank Ortho-Kinetics Inc. for their assistance in the development of a new manual prone cart.

Mark Cors, Research Service Clement J. Zablocki VAMC 5000 W. National Avenue Milwaukee, WI 53295.1000 414.291.8069 (voice) 414.291.8077 (fax)