Transcription
DepartmentVeterans AffairsJournal of Rehabilitation Research andDevelopment Vol . 37 No . 3, May/June 2000Pages 373—382CLINICAL REPORTDesign of the advanced commode-shower chair for spinalcord-injured individualsPascal Malassigne, MID, IDEA? Audrey L . Nelson, RN, PhD ; Mark W. Cors, BFA ; Thomas L. Amerson, PhDResearch Service, Clement J . Zablocki VAMC, Milwaukee, WI 53295-1000 ; Milwaukee Institute of Art and Design;Nursing Service, James A . Haley VAMC, Tampa, FL 33612 ; Dept . of Physical Medicine and Rehabilitation, MedicalCollege of Wisconsin, Milwaukee, WI ; Gales Ferry, CT.Abstract—The purpose of this development project was todesign a new commode-shower chair that can be safely used byindividuals with spinal cord injuries (SCI) and their caregivers.The need for this new design was consumer-driven . Patientsand caregivers identified the following fatal flaws in the commode-shower chairs used in Spinal Cord Injury (SCI) centers:1) risk for patient falls during transfers, propelling, and whileleaning over for showering ; 2) risk for pressure ulcers due toinadequate padding and seat positioning for lengthy bowel careregimes ; 3) inadequate caregiver access to the perianal area ofthe patient to perform bowel care procedures ; and, 4) wheelrelated inability to properly position the chair directly over thetoilet . The new, self-propelled chair addresses each of theseconcerns . Lockable, swing-away, pivoting armrests andimproved, lever-activated brakes were designed to facilitatesafe transfers . An innovative foot-lift was invented to facilitatewashing of feet. Larger handrims were designed to aid inpropulsion in wet environments . To prevent pressure ulcers, achair frame and padding combination was designed to facilitatea seating position that optimally distributes body weight to prevent the development of pressure ulcers in the sacral and ischialareas . To address the common risk of heel ulcers, footrests, featuring edgeless, rounded heel cups, were designed . A new tubular chair frame, a new seat and smaller wheels were designedto enhance caregiver access and ensure proper chair positioning over the toilet. Following its successful clinical evaluationat the Milwaukee and Tampa VA Medical SCI Centers, theAdvanced commode-shower chair is being patented by theDepartment of Veterans Affairs (VA) . The VA has partneredwith Everest & Jennings , to make this chair available commercially.Key words : activities of daily living, spinal cord injuries,wheelchairsINTRODUCTIONThere are over 220,000 individuals with spinal cordinjury (SCI) in the United States today (1) . The majorityof them have bowel incontinence, requiring bowel carean average of three times a week . While some are able totransfer to a toilet for bowel care, many need to use acommode-shower chair. Most of the existing commodeshower chairs were designed for the elderly, and do notThis material is based on work supported by the Rehabilitation Researchand Development Service, Department of Veterans Affairs, WashingtonDC 20420.Address all correspondence and requests for reprints to : Pascal Malassigne,IDSA, Research Service, 151, Clement J . Zablocki Veterans Affairs MedicalCenter, 5000 West National Avenue, Milwaukee, WI 53295-1000; email:pmalassi@miad .edu .373
374Journal of Rehabilitation Research and Development Vol . 37 No . 3 2000meet the needs of a younger SCI patient population managing a neurogenic bowel . A survey of 147 veterans withSCI was conducted to evaluate existing commode-shower chairs (2,3) . Findings revealed numerous safety-related problems with existing chairs . Specifically, 66 percentfelt unsafe self-propelling, and 47 percent felt unsafetransferring to an existing commode-shower chair . Fortytwo percent indicated that the brakes were unreliable.Twenty-four percent reported development of pressuresores and cuts from the seats and 35 percent indicatedfalling from commode-shower chairs . Of those whoreported injuries due to fall, over 23 percent were hospitalized ranging from 1 mo to 4 yr . Patients reported flawsin commode-shower chairs that negatively impacted theirquality of life, self-esteem, and physical well-being.METHODSBefore beginning the new chair design, the authorsevaluated existing chairs as part of VA Rehabilitation R&DService pilot study . This evaluation involved the designand clinical use of the chair by patients and caregivers.From this evaluation, functional and performance criteriawere established in order to develop chair prototypes forclinical evaluation at the Milwaukee and Tampa VAMedical Centers . Typical of many such projects, an iterative process of prototype development, laboratory evaluation, and clinical evaluation was used to develop this newchair. The responses received from patients and caregiverswere incorporated into the next prototype until the newchair design was completed . During the process, severalnew features were invented : a new seat design, a foot-lift,oversized pushrims, swing-away pivoting armrests andnew footrests featuring edgeless heel cups (Figure 1).Two chairs, one self-propelled and the other anassisted-care chair, were actually designed; however,only the self-propelled chair (the Advanced commodeshower chair) was clinically evaluated.Safety and Performance CriteriaSafety and performance criteria were delineatedbased on consumer input, data from pilot studies (2-8), aswell as International Standards Organization (ISO)American National Standards Institute/RehabilitationEngineering Society of North America (ANSI/RESNA)wheelchair standards (9), as recommended by the fundingagency. The chair was designed based upon the followingsafety and performance criteria:Figure 1.The Advanced commode-shower chair. Overall chair safety : The new chair must not contributeto the development of pressure ulcers, nor cause injuriesto patients due to falls while transferring, bending forward to shower, or propelling the chair in wet environments. Chair positioning over a toilet : The chair must fit properly over a toilet bowl to prevent fecal matter from fallingon the floor . While this seems like an obvious need, thewheel size of existing models prohibits proper chair positioning over the toilet bowl, making this a hygiene problem and a threat to the dignity of the patient andcaregiver. Seat design : The chair must have a waterproof seat thatprovides full thigh support, thereby minimizing pressureon the sacral and ischial areas . The seat must be cushioned for appropriate pressure relief and designed for
375MALASSIGNE et at . Commode-Shower Chair Designhand access to the perianal area, necessary for bowel careprocedures, such as digital stimulation (10). Seating position : The seat must be sloped toward theback to hold the user safely in place . Multi-function armrests must provide a resting-place for the forearms of theusers, support their body weight, and create areas forbody positioning. Hand access to the perianal area : The chair must provide unrestricted under-seat hand access to the perianalarea from at least three positions (right, left, and front). Caregiver friendly : The chair must provide for unrestricted hand access to the perianal area of the patient.The footrests must adjust easily for users of varyingsize and weight . The chair armrests must be able toswing away for ease in transfer, but should not beremovable, since they are likely to be lost in institutional settings. Durability/rust-proofing : The chair must survive longterm use in wet environments. Propulsion pushrims : The chair must have appropriately sized pushrims for optimum hand positioning and grip.The handrims must be coated with non-slippery materialto assist propelling in wet environments. Static stability : The chair must be designed for a minimum tip angle of 20 in forward, rearward, and sidewaystipping. Design of two versions : Two rigid chairs were developed—a self-propelled and an assisted-care version.Development ProcessBoth the self-propelled chair and the assisted-carechair were designed and engineered ; however, it is theself-propelled chair for which prototypes have been tested, and clinically evaluated.The project began with the design of an adjustablechair frame, in order to establish the proper relationshipbetween the seat, the toilet bowl, and the bathroom wall.With the frame geometry established, all other aspects ofthe development of the chair followed.This design and development process is presentedusing ANSI Wheelchair Standards #00 (WC/00) nomenclature (9) .Body SupportWC/00 defines the body support system as "Thoseparts of the wheelchair which directly support or containthe body of the user."(9).Pressure, positioning, and postural support are critical aspects in the design of a new commode/shower chairfor persons with SCI (4) . A properly fitted chair disperses weight over the entire length of the thighs . To accomplish this, footrests must be adjusted until the thighs areparallel to the ground . If the feet are too high, the weightis thrown back on the bony protuberances of the buttocks.If they are too low, the weight comes forward onto thethighs, causing pressure ulcers (4,5).Seat DesignTwo types of seats were developed for clinical evaluation : square and rectangular.Square seats : a repositionable, square seat with anopening to one side is common on commercially available commode-shower chairs (6) . The main advantage ofa square seat is that the opening can be rotated on anyside depending on the preferences and abilities of theusers or caregivers ; however, its disadvantage is the limited thigh support area, typically much shorter than thethigh length of the user . Forty square seats were designedwith various foam densities and openings . These seatswere evaluated with a pressure-mapping system (4,5),with results showing dangerously high pressure at theseat opening, even when an optimal foam density wasused . An optimal foam density provides maximum support, comfort, and pressure relief . These results confirmed the idea that the disadvantages of square seatsoutweigh their positive aspects (rotation on all sides) andled to concentration on the design of a fixed, rectangularseat for the new chair.Rectangular seats : several seats of various dimensions and sizes of hole opening were developed and evaluated with the pressure-mapping system . From thesevarious designs, a new "C" shape seat was created,allowing hand access by the caregiver in three positions(front, left and right side) . This seat measures 49 X 54 cmand incorporates front "wings" projecting on the sides tofacilitate wheelchair to wheelchair transfers (Figure 2).Seat CushioningIn developing seats, the authors experimented withtwo types of open cell conforming and cushioning foams.Brands used for conforming foams were Pudgee andSun-Mate while Laminar and Clark were used for the
376Journal of Rehabilitation Research and Development Vol . 37 No . 3 2000oting armrests, capable of holding patients weighingupward of 100 kg and more, were designed . In the lockedposition, users can latch under them and pull up withoutfear that they will detach . To meet needs identified bycaregivers in institutional settings, the two armrestsswing away without being removable : a lever releasemechanism was developed to lock and unlock them . Foradded comfort, longer armrest pads have been selected toprovide more surface area for the arms and elbows(Figure 3).Figure 2.Seat with side wings.cushioning foams . Four different foam densities wereevaluated for each brand . The seats were tested with theForce Sensing Array (FSA) pressure-mapping system.This system uses umcut-mized sensing pad with a graphicdisplay to measure the full buttock-seat interface (11).Recommended maximum acceptable pressures for persons with SCI have been established (12) . Testinginvolved recording the amount of pressure being exertedon the surface of the seat by a variety of patients, chosenbased on their level of risk, defined as high (no sensation,with history of sores at the site of measurement), moderate (no sensation, no history of skin breakdown), and low(partial or full sensation, no history of skin breakdown).The results indicated that low-pressure readings weredependent not only on the amount of padding, but also onthe position of the body in the chair.The design of the chair significantly impacted bodypositioning, affecting the angle of the seat, angle of thebackrest, and position of the seat opening . The authorsconcluded that the seat cushioning of the chair must workin concert with the frame to achieve safe pressure levels.From the various tests, Clark firm foam was selected forthe final design, based on effective pressure relief andcost.Swing-away ArmrestsArmrests are used in multiple ways : to help positioning in the chair or transfer into/out of it, to rest thearms, to lift and hold up on the armrests, to hook up or putthe arms under the armrests, to brace in the chair for stability, and to push down on the armrests to shift the bodyon the chair. Based on these multiple uses, lockable piv-Figure 3.Swing-away armrest and armrest release lever.FootrestsFootrest AdjustmentThe ability to adjust footrests in accordance with theheight of the patient is critical in establishing a good seating position for bowel care, yet footrests typically requirethe use of tools for adjustment . This is particularly problematic in institutional settings where multiple users areof varying heights. Since tools are seldom available onhospital units, footrests are rarely adjusted for the heightof each patient, and this lack of adjustment can force thepatient to sit in an awkward position, predisposing him orher to increased risk for pressure ulcers . In developingnew footrests, the authors used telescoping footrest postsand two different locking mechanisms : 1) a quick releasesystem used for racing bicycle wheel removal, and 2) ahandle . In clinical evaluations, the quick release systemconfused caregivers unfamiliar with this technology.Although the handle required more tightening strength, itwas intuitively easier to use . The footrest and the lever-
377MALASSIGNS et al . Commode-Shower Chair Designtype handle become a single moveable unit, adjustedalong the entire length of the post and easily tightenedwithout the need for tools . This udinntmeut mechanismwas designed for caregivers in institutional settings, sincechairs used in a home setting rarely need to be modifiedonce they are initially adjusted for the thighs of the individual user (Figure 4).Figure 5.Rounded footrest.independent and safe cleaning of the feet and legs . Thefootlift is a hinged mechanism that hangs in front of theframe when not in use . To use dzofouUift, the user swingsit up into position and manually brings each foot up intothe heel-cup to wash it (Figure 6).Figure 4.Footrest adjustment.Footrest DesignTypically, existing footrests are flat metal platesincorporating a heel-strap supported by two vertical bolts.The bolt heads are often sharp and can cut patients'ankles, unprotected during bowel care and showeringprocedures . Footrest development started with designsthat held the entire foot instead Of only the heel . The newdesign is a footrest with a deep heel-cup, contoured to fitthe bottom of the foot . To avoid potential ankle injuries,all edges of the footrests are rounded and smooth, andthey are easy to clean and drain when showering . Thisimproved design helps with weight distribution on thethighs (Figure 5).FootliftIt is not uncommon for users to fall out of the chairwhile trying to reach their feet during showering.Discussions with users about showering in a chairrevealed two techniques for safely washing their feet:using a long brush and lifting the leg over a bathtubledge, the latter being the inspiration for the new foot-liftdcmigu,uunique and innovative accessory that allows theFigure 6.F o onift.Commode PanThe commode pan is used as an accessory when atoilet is not available . Typical commode pans can be Jifficult to use, since they are small and have limited grasp-
378Journal of Rehabilitation Research and Development Vol . 37 No . 3 2000ing areas . They are also difficult to remove from thechair, and spills are common . As a solution, the authorsdeveloped a tray, supported by the chair frame andequipped with a recessed pocket, to hold the pan in place.Removal of the pan is performed easily by sliding itacross the tray for emptying and replacement (Figure 7).Driving Wheels Selection Process : Self-propelledChairThe team selected wheels of 50 and 55 cm in diameter, instead of the customary 61-cm wheels, for clinicalevaluation . While the standard wheel size provides easierhand access to the pushrims, it also creates problems bybutting against the wall before centering over the toilet . Thedecision to use smaller wheels solved access over the toiletbut made self-propelling slightly more difficult . In clinicalevaluation, participants preferred the 55-cm wheel size tothe 50-cm wheels . Consequently, this size wheel was selected fhrtbe self-propelled chair. While the new wheel dimension is slightly more restrictive, it must be noted thatself-propelling with a commode-shower chair is limited toshort distances, generally from bedroom to bathroom.Assisted Care ChairWheels of 32 .5 cm in diameter will be used for thisversion of the chair, intended for patients that need caregiver assistance.Figure 7.Commode pan.BackrestTypically, the backrest of shower chairs is rigid andmade of non-breathable, solid vinyl material . In someinstances, its height interferes with access to the patient'sback for showering . In the new design, a soft, openweave, nylon mesh was selected to facilitate showeringand drying . Clinical evaluations in hospital and home settings revealed that the mesh material was easily cleanedand self-drying between uses.Driving WheelsWC/00 (9), defines the driving vvhcol o[u wheelchair as "a wheel that is connected to the driving systemand when in contact with the underlay develops the propelling force ." Typical commode-shower chairs areequipped with 61-cm diameter wheels and 2-cm diameterouetdbunddnus . In designing a chair that must roll over atoilet and must be used for showering, it was critical toconsider self-propelling and gripping in wet environments . Additionally, it was necessary to select a wheelsize that would enable level access to the seat from another chair and would not touch the back wall before centering over the toilet .Pushrim DevelopmentThe team used ergonomic data on the dimensions ofthe hand, combined with knowledge from previous studies related to grab bar design, to develop new pushrims.The goal was to increase the surface area for the handswhen grasping the pushrim . A test mock-up was built,made of curved PVC tubing and mounted to the wheel ofa wheelchair, with 3 different diameters : 27, 35, and 42mm . It was then possible to compare one size handrim toanother. Ten veterans with SCI participated in a patientpreference study of the three diameters . The 35-mm wasthe preferred size, and was produced in aluminum andcoated with rubber. The larger pushrims were mounted onthe new chair prototypes . The new pushrims are 15 mmlarger in diameter—35 mm instead of 20 mm—andenable users to achieve a stronger grip . The enhancedgrasping ability in a wet environment, with the rubbercoating handrims, was greatly appreciated in the clinicalevaluations (Figure 8).Caster WheelsWC/0(9),defines dhe caster wheel of wheelchair as"A wheel that can pivot but is not intended to govern thedriving direction." Standard 15-cm caster wheels were usedon all the chair prototypes, with the stems mounted insidethe frame to protect the bearings from rusting . After 12months of clinical evaluation in two active hospital settings,no rust was detected on any of the prototypes .
379MALASSIGNE et al . Commode-Shower Chair Designmodel, was tested for static stability and for forward,rearward, and sideways tipping (7).Figure 8.Oversize pushrims.Parking BrakesWC/00 (9), defines the parking brake as : "The braking system that is intended for keeping the wheelchairstationary on sloping ground whether or not the wheelchair is occupied ." Lever-type parking brakes wereselected for all the chair prototypes . Clinical evaluationindicated complete user satisfaction with these brakes.Frame Development and Static Stability TestingWC/00 (9) defines a wheelchair frame as follows:"The frame unites and supports the other parts of thewheelchair. Seat-frame-backrest, etcetera, could form, orbe combined into, one unit or consist of separate parts ."An adjustable chair frame was developed in order toestablish the proper relationship between the seat, toiletbowl, and wall . This adjustable frame allowed changes inthe distance between the seat and the rear wheels . Thedevelopment of later frames used this optimal seat-towheel relationship.The frames were tested for static stability with theANSI Wheelchair Standards : WC 01 : Determination ofStatic Stability, for forward, rearward and sideways tipping (7,9). Static stability was measured when the chairwas positioned on a platform with a 75-kg subject. Theplatform was tilted up-slope and tipping was achievedwhen the front or rear wheels of the chair lifted off theplatform . The same procedure was repeated with a 100kg subject . Frame configurations were modified until a209 tipping angle was established . This configuration wasused throughout the development process and is on thefinal frame design . The new chair, the self-propelledClinical EvaluationThe development of the new, self-propelled chairinvolved an iterative process of prototype fabrication, andlong term clinical evaluation at the Milwaukee andTampa VA Medical Centers . The primary evaluationmethod used one questionnaire for patients and one forcaregivers . The secondary form of prototype evaluationinvolved discussions and focus groups with patients andcaregivers about the prototypes provided for clinicalevaluation.Chair assessment: patients and caregivers used questionnaires addressing issues of their interaction with thenew commode-shower chair. The questions were relatedto the features of the chair relative to bowel care andshowering, issues of seating, and transfer safety to andfrom the chair.RESULTS AND DISCUSSIONReflecting the need for a proper seating position askey to a safe and functional chair, the Advanced commode-shower chair (the self-propelled chair) offers thefollowing features: Seat designed with wings extending to the front cornersto allow more area for transfers and grasping, and a largecutout area for under-seat hand access; Oversized and non-slip pushrims, fitting properly in thehand; Easily adjusted and contoured footrests; Locking, swing-away armrests; Footlifts that allow the user to wash feet and legs independently and safely; Smaller wheels to allow for a closer position to the walland to center over the toilet; Handles at the top of the backrest, bent past 90 , to helphold the patient's arm in place when wrapped around it, and Absence of sharp edges on the chair, for safe and easygrasping .
380Journal of Rehabilitation Research and Development Vol . 37 No . 3 2000Dimensions for the two chairs (self-propelled andassisted care) are depicted in Figure 9 . The self-propelledchair is 102 cm high, 70 cm wide and 108 cm long . Theassisted care chair is smaller : 102 cm high, 60 cm wide,and 70 cm long.propelled chairfTable LStatic stability testing results.Static tipping angles75 kg100 kgn.n .nToward the rear2323Toward the front2018Toward the side2121All measures are in degrees.age static stabilities between the 75-kg and 100 kg subjectsin the rearward and sideways tipping tests . The static stability difference of 2 2 between the averages for the 75-kgand 100 kg subjects in the forward tip testing is minimal.Overall heightOverall lengthOverall widthSeat heig tThor60 crn --*-11iromFigure 9.Dimensions for the self-propelled and assisted care chairs.Static Stability TestingThe results presented in Table 1 below, indicate thatthe chair is very stable . There is no difference in the aver-Clinical EvaluationOverall CommentsThe new chair was found to roll as easily as otherchairs . The chair did fit conveniently in shower stalls andover toilets, and improved showering and toileting, viathe many places available for patients to grasp and hold.The chair held the patients in an appropriate position andprovided a wide, comfortable seat.Chair StabilityBoth the patients and the caregivers considered thebrakes easily activated and effective in holding the chairin place . Patients and caregivers found the chair stableduring showering and bowel care.TransferringThe patients found the footrests and armrests easy tomove out of the way for transferring . Neither the curvedfront seat supports of the frame nor the footlift interferedwith transfers . The caregivers found the brakes effectivein holding the chair in place during transfers, with no evidence of sliding or giving way over the duration of the12-mos evaluation . Overall, the patient and caregiverresponses to the final chair prototypes were unequivocaland strongly favorable.BackrestCaregivers reported that the backrest provided sufficient space to wash the back, and the open weave fabric ofthe backrest was easy to clean and dry . The patients reported that the backrest was comfortable, with an appropriateheight and a bottom edge that was not too low.
381MALASSIGNE et aL Commode-Shower Chair DesignSeating ComfortPatients responded that the seat was comfortable andnot too firm . Both patients and caregivers were able toreach under the seat easily . They found the opening of theseat to be an adequate size and the seat cover material notoverly slippery when wet . The patients felt secure and didnot feel that they were falling into the seat opening.Access to the perianal area was adequate for digital stimulation necessary for bowel care procedures.ArmrestsThe armrests were found to be strong, with comfortable armrest pads . In addition, patients liked the curvedends of the armrests for grasping . The armrest length andheight were rated as ideal.FootrestsThe footrests were found to hold the patients' feetproperly and safely in place, and to be easily adjustableby caregivers.FootliftThe footlift did not interfere with patient transfer.However, because of its location (slightly hidden under theseat of the chair), patients expressed concern, at first, regarding its use and operation, while caregivers favored it . The initial hesitancy of some patients to use the footlift is likelyexplained by the novelty of this new wheelchair feature . Overtime, patients became familiar with its use . Both patients andcaregivers found the footlift made washing of feet easy, andcaused no discomfort or loss of balance for patients.PushrimsThe large pushrims reveived postitive responses fortheir gripping effectiveness when wet and for the fact thatthey were much larger than the standard pushrims.CONCLUSIONSThis 2-yr development project enabled the successfuldesign of two versions of a rigid-frame commode-showerwheelchair: a self-propelled and an assisted care chair.During the clinical evaluation of the self-propelled chair,caregivers and patients suggested that a folding commodeshower chair be designed for home use. With sponsorshipof the VA Rehabilitation R&D Service, and in collaboration with Everest & Jennings, the design of a folding commode-shower wheelchair is nearly completed .PatentingAn invention report was submitted to the Office of theVA General Counsel by the authors . Following positivereview, the VA decided to patent the many new and innovative features of the Advanced commode-shower chair.Technology TransferThe authors first collaborated with Milwaukee-basedOrtho-Kinetics {OKI) during the development stages ofthe Advanced commode-shower chair . However, OKIdecided not to commercialize this chair when it was completed . The chair was then presented to lnvacare", ActiveAid and Everest & Jennings . Although both Active Aidand Everest & Jennings were interested in the new chair fortheir product line, Everest & Jennings decided to manufacture and market the chair under a licensing agreement withthe Department of Veterans Affairs.REFERENCES1. Stover S, DeLisa J, Whiteneck G . Spinal cord injury : clinical outcomes from the model systems. Gaithersburg, MD : Aspen ; 1995.2. Nelson AL, Malassigne PM, Amerson TL, Binard J, Saltzstein R.Descriptive study of bowel care practices and equipment in spinalcord injury . Spinal Cord Injury Nurs 1993 ;10(2) :65—7.3. Malassigne PM, Nelson AL, Amerson TL, Binard J, Saltzstein R.Design of a new bowel care chair for spinal cord injury : a pilotstudy. Spinal Cord Injury Nurs 1993 ;10(3) :84—90.4. Nelson AL, Malassigne PM, Murray J . Comparison of seatingpressures on three bowel care/shower chairs in SCI : results of apilot study. Spinal Cord Injury Nurs 1994 ;11(4) :104—6.5. Malassignd PM, Nelson AL, Murray I Determination of static stability of bowel care/shower chairs . Proceedings of the 17th AnnualRESNA Conference ; 1994 Jun 17-22; Memphis, TN . Washington,DC : RESNA Press ; 1994. p.318—20.6. Malassigne PM, Nelson AL, Amerson TL, Saltzstein R, Binard J.Evaluation of three bowel care-shower chairs . Proceedings ofRESNA International 92 ; 1992 Jun 7-10 ; Toronto, ON, Canada.Washington, DC : RESNA Press ; 1992 . p . 271—3.7. Malassigne PM, Amerson TL, Nelson AL . Determination of staticstability of bowel care/shower chairs in spinal cord injury.Proceedings of the 17th Annual RESNA Conference ; 1994 Jun 1722 ; Memphis, TN . Washington, DC : RESNA Press ; 1994 . p.318-20.8. Malassigne PM., Nelson AL, Cors M, Amerson TL . Design anddevelopment of a new commode-shower chair. Proceedings of the20th Annual RESNA Conference ; 1997 Jun 20-24, Pittsburgh, PA.Washington, DC : RESNA Press ; 1997, p . 202-4.9. Amer
Medical Centers. Typical of many such projects, an itera-tive process of prototype development, laboratory evalua-tion, and clinical evaluation was used to develop this new chair. The responses received from patients and caregivers were incorporated into the next prototype until the ne
