clinical analysis of a cad/cam system for custom seating: a … · 2005. 8. 23. · cad/cam seats...

Department ofVeterans Affairs

Journal of Rehabilitation Research andDevelopment Vol . 33 No . 3, July 1996Pages 311–320

CLINICAL REPORT

Clinical Analysis of a CAD/CAM System for Custom Seating:A Comparison with Hand-Sculpting MethodsEdward D . Lemaire, MSc ; David Upton, BSc ; Joseph Paialunga, BScOT(C) ; Guy Martel, MHSc, CPO(C);Jacques BoucherThe Rehabilitation Centre, Ottawa, ON, Canada KIH 8M2 ; Centre de Readaptati.on Lucie Bruneau, Montreal, PQ,Canada H2H 2N8

Abstract—A CAD/CAM system for manufacturing customseating inserts was evaluated within a moderately to severelydisabled population . Using the Otto Bock Shape System, 25CAD/CAM seats were manufactured at a remote facility andcompared to 9 seats manufactured using hand-sculptingtechniques . Clinician and client questionnaires were com-pleted for each seat to assess satisfaction, fitting/manu-facturing times, and to collect demographic data . TheCAD/CAM method was significantly better (p

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Journal of Rehabilitation Research and Development Vol . 33 No. 3 1996

Manual seating insert fabrication requires minimalequipment, uses readily available materials, and pro-vides a simple and quick solution for less complicatedsituations . Patients with more complex spinal devia-tions, however, may require a more accurate definitionof surface contour . Manual manufacturing techniquesrely on the "artisan" skills of a technician to sculpt therequired shape . Since linear measurements and clinicalnotes are the only information available for designing ahand-sculpted insert, additional modifications and mul-tiple fitting sessions may be required to obtain the finalshape (i.e ., the client must try the insert before changescan be identified) . Carving a complex shape by handalso involves many hours of technical time.

One mechanical system for determining seat shapehas been developed using a matrix of small, interlock-ing, metal and plastic cells . To create the shape, theclinician changes the matrix's inter-cell positions untilthe desired contour is achieved (2,3) . A foam cover isplaced between the client and the matrix to finish theinsert . This technique is mechanically uncomplicated,can be fit to almost any spinal shape, and allows theclinician to modify the shape during the fitting session.Despite these advantages, the matrix method is timeconsuming, since each cell has to be individuallyadjusted ; it is difficult to fit since changes to one seriesof cells can change the tissue orientation in another areaof the matrix ; and it requires regular service to insurethat the cells have not moved.

Foam-in-place systems have also been used as aone-step method of obtaining the shape of a seatinginsert . This method involves positioning the client in awheelchair, or fitting chair, and placing a bag betweenthe body and the chair. Various chemicals are mixed inthe bag to produce a foaming reaction . While the patientis held in position, the foam-filled bag is quicklymanipulated to the correct orientation and held until thefoam hardens . The resulting hard or soft foam is handmodified and covered to provide the custom insert . Thissystem is an acknowledged means of insert fabricationdue to the fast production time, minimal technicalrequirements, and variety of foam densities . Clinically,the setting time of the foam can be a disadvantage, sinceminimal time is available for positioning the client.Inadequate chemical mixing facilities in a clinic mayalso lead to inconsistent results, such as air bubbles inthe hardened foam or areas that are not cured . Sincefoam-in-place chemicals (isocyanates) are also healthhazards, these systems are not ideal for most clinicalenvironments .

A custom seating method similar to foam-in-placeis described by Colbert, Doyle, and Webb (4) . Thissystem (DESEMO) involves adding epoxy to a latexbag filled with polystyrene beads . After the bag issealed and kneaded, it is placed in the wheelchair andthe patient seated upon it . The seat is then molded tothe desired orientation while a vacuum is applied to thebag. The vacuum is required to retain the seat shapeuntil the epoxy cures (approximately 6 hours) . Thehardened seat is fitted with straps, modified after a 2-to 3-week trial period, and painted. Although thissystem is useful, the extra equipment requirements,long cure time, and the need for mixing toxicchemicals may contraindicate its use in favor of othersystems. The main benefit of this approach overtraditional foam-in-place methods is that the initialfitting time is much longer . A client can be left in thebead-bag for a few hours to test whether the seatingsystem is functioning correctly before the resin hascured. While the DESEMO system is not commerciallyavailable, other bead-bag and foam systems are cur-rently in use.

Another bead-bag-and-vacuum method of obtain-ing a custom insert shape uses plaster bandages insteadof active chemicals to save the shape (5,6) . A latex bag,filled with expanded styrofoam beads, is placed in awheelchair or fitting chair and the subject positioned onit. The shape of the bag is changed until the final insertcontour is reflected in it . Once the preferred contour hasbeen achieved, air is removed from the bag using avacuum pump . With the air removed, the bag retains itsshape, since the beads have "consolidated into asemi-rigid matrix ." The shape of the bag is subse-quently copied by making a plaster of Paris bandageshell from its surface . The insert is then manufacturedby foaming up to the negative cast, either on-site or at acentral fabrication center.

This system has the benefits of being easy to applywithout requiring dangerous chemicals during the as-sessment session, providing unlimited initial fittingtime, and requiring minimal equipment when a centralfabrication facility is used to produce the insert . If insertfabrication is performed on-site, the problems associatedwith toxic chemical foams and technical time must beconsidered . While remote central fabrication (i .e ., send-ing the cast to a company with the facilities tomanufacture the insert) saves clinical and technicaltime, some error many be introduced due to castpositioning and alignment . The plaster cast methodrequires more technical/clinical time and more materials

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CLINICAL REPORT : CAD/CAM System for Custom Seating

than both the DESEMO system and manual method, butnot as much time as the matrix method.

A custom seat shape can also be defined usingcomputer-aided approaches . Weishaupt discusses a mea-surement method that involves a series of 91 pressuresensors located in a sling-test seat (7) . As the patient sitsin the chair, pressure transducer deformation reflectsseat deformation. Through proper calibration, the pres-sure distribution can also be obtained . AlthoughWeishaupt used this system for seat evaluation only, itcan also be used to generate a surface map forCAD/CAM systems.

Sprigle, Chung, and Brubaker use a CAD/CAMseating system to investigate the effect of foam densitieson cushion function (8) . The buttock shape is obtainedfrom a positioning system consisting of 64 linearpotentiometers arranged in a 16x16 in (40 .64x40.64cm) grid. Once the patient is seated on the grid, thepotentiometer deflections were collected using a com-puter ; the data are expanded to a 33x33 array, reviewed,and the resulting shape carved using a numericallycontrolled milling machine . The use of CAD/CAM forcustom cushion production improves experimental con-trol since the shape is exactly reproduced for each testcushion. Due to the lack of normal pressure exerted bythe back, the use of linear potentiometers may not beadequate to obtain the seat back contour.

CAD/CAM should improve current custom seatingmethods by:

• decreasing the time required for the seat manufactur-ing process• providing data files for remote insert fabrication(central fabrication)• providing a method for determining the patient'sshape without the use of potentially hazardous chemi-cals• saving the shape data on disk for later retrieval(assess previous clinical interventions, make additionalinserts, and so forth)• improving inter-clinician communication since thedata file can be viewed on screen before the seat isfabricated, transferred to another computer, or displayedon a computerized conferencing system• providing a more efficient platform from which toservice remote areas (i .e ., mobile clinic)• improving seating research by providing a morecontrolled manufacturing approach (testing differentmaterials, testing different clinical interventions, and soforth) .

Most of the methods described in this documentfor custom seat fabrication are presently in use;however, clinical CAD/CAM methods are not ad-equately described in the literature. The possible ben-efits of an efficient and valid CAD/CAM seating systemwould suggest the need for further research into thisarea . This paper describes a clinical evaluation projectthat examined time requirements, clinician satisfaction,and client satisfaction with a commercially availableseating CAD/CAM system.

METHODS

CAD/CAM and Manual Manufacturing SystemsAll CAD/CAM seats were manufactured using the

Otto Bock Shape System (OBSS : Otto Bock Ortho-paedic Industry of Canada Ltd ., Winnipeg, Manitoba).This system uses the bead-bag-and-vacuum approach tomake a temporary seat for the client (5,6) and amagnetic digitizer/micro-computer assembly to recordsurface contour manually (9) . The digitizing unit locatesthe three-dimensional (3-D) position of a hand-heldstylus by creating a magnetic field about the bead bag,determining the strength of the field at the styluslocation, and scaling the field strength to x, y, and zdistances . The clinician or technician digitizes a seriesof medial/lateral, parallel lines along the bead bagsurface by positioning the stylus on the bag andpressing the mouse button of the computer (Figure 1).These data points are used to interpolate a mathematicalrepresentation of the insert shape.

Figure 1.Digitization on the OBSS system .

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The CAD software displays the mathematical

Table 1.surface as a series of 3-D on-screen images . An Disability ratingon-screen shape can be viewed, digitization lines can beremoved and redigitized, and seat dimensions can bechanged. When the correct insert image is obtained, theshape data file is saved and sent through a modem to acentral fabrication facility for manufacturing.

The received data files at central fabrication aretransferred to a numerical computer-controlled carver . Anegative model of the insert is carved from a block ofstyrofoam and used to produce the device . By foamingup to the negative model, a variety of foam densitiescan be used in production.

The minimum OBSS system requirements are a386-based computer with a math coprocessor, VGAgraphics, 4 Mbytes RAM, and 10 Mbytes of hard diskspace. A notebook computer is recommended whenusing OBSS at more than one location . The software iscustom made for seating and loaded as a stand-aloneDOS application . A magnetic digitizer comes with theOBSS package.

For this study, all clinical work was performed atThe Rehabilitation Centre in Ottawa and the Centre deReadaptation Lucie Bruneau in Montreal . All CAD/CAM inserts were fabricated at Otto Bock OrthopaedicLtd. in Winnipeg and adjusted and mounted at theclinical facilities . Removable covers were used on allseats to allow for final adjustments on-site.

In addition to the CAD/CAM inserts, baseline dataon hand-carved seating inserts were collected from asimilar group of clients at The Rehabilitation Centre.This information was used to compare clinician times,fabrication times, insert ratings, and client satisfaction.

SubjectsAll subjects involved with this study were recruited

through the Special Seating section of the Prostheticsand Orthotics Service at The Rehabilitation Centre andthe seating clinic at the Centre de Readaptation LucieBruneau . A disability rating scale, shown in Table 1,was used as the subject selection criterion (10).Admittance to the study was initially restricted topeople with a disability rating over 3 ; however, twosubjects from the Lucie Bruneau site with a level 2rating were included since the CAD/CAM approach wasconsidered appropriate for their condition . One seatingclinician from each of the centers did all clientassessments. Two education sessions were held beforedata collection began to ensure that the cliniciansunderstood and applied the scale in the same manner .

scale.

Rating Description

1

good head and trunk controlsymmetrical posturing easily attainablejoint ROM within normal limits

2

fair to poor head and trunk controllimited ROM in jointssymmetrical posturing attainableincreased spasticity over level I

3

moderate deformities (flexible scoliosis, flexible kyphosis)possible flexion contracturesfoot and ankle deformities90/90/90 position attainable

4

flexible and fixed deformitiespelvic obliquityflexion contractures greater than 120°some difficulty in attaining 90/90/90 posture

5

severe, fixed deformitiesmajor limitations of ROM due to contractureextreme difficulty attaining and retaining seating postures

ROM = range of motion.

All subjects were divided into two groups : a groupwho received a CAD/CAM seating insert and a groupwho received a conventional insert . The conventionalinsert group was recruited from the RehabilitationCentre over a 4-month period before starting theCAD/CAM system evaluation . During this time, all butthree subjects who matched the selection criteria wereincluded in the comparison group . The three subjectswho were not included had severe (level 5) spinaldeformity and were fitted using foam in place (twocases) and casting (one case) . After the conventionalinsert data were collected, a second group of subjectswas recruited in the same manner and fitted withCAD/CAM-produced custom contoured seats . Informedconsent was obtained from all subjects . Demographicdata, including gender, date of birth, disability, anddegree of disability, were collected for each clientduring the first clinic visit.

Data CollectionClinician and client questionnaires were completed

for all seating inserts. One clinician from each centercompleted the clinician questionnaires for their respec-tive sites, recording information on the prescribed

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device, the time required to assess the client, the timelag for seat manufacturing, the custom insert rating, thetime required for final fitting, and whether the finishedseat was acceptable for dispensing . The initial and finalfitting sessions were held on separate days.

One questionnaire was completed for each seatingsystem. An acceptable insert manufacturing time (cen-tral fabrication time) was considered to be 2 weeks . Allother items were compared between the CAD/CAM andmanual modification groups . Clinician insert ratingswere based on the modification scale shown in Table 2.

A client questionnaire was administered by mail 3months after the device was dispensed, to obtaininformation on insert design, durability, comfort, appro-priateness, and general comments . These questions wereincluded as part of a quality assurance questionnairecirculated in either English or French versions to allpatients seen at the centers.

Data AnalysisAll questionnaire data were analyzed using de-

scriptive statistics . The patient and clinician responseswere compared by gender, age, disability, and level ofdisability . A Mann-Whitney U test was used to comparethe clinician and client questionnaire results between theCAD/CAM and conventional groups . The on-site manu-facturing and fitting time associated with the CAD/CAM approach were compared to conventional on-sitemanufacturing and fitting times using t-tests (p

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Table 3.Time required for CAD/CAM and conventional seatfabrication (average and standard deviation (SD) for allsubjects).

Measure Units Average SD

CAD/CAM Initial fitting time hours 1 .1 0 .5Central Fabrication time days 39 .1 17 .4On-site Fabrication time hours 2 .5 2 .5Final fitting time hours 1 .0 0 .6

Conventional Initial fitting time hours 1 .2 0 .8On-site Fabrication time hours 15 .0 3 .6Final fitting time hours 1 .2 0 .6

inserts, this referred to the client contact time beforefabrication starts.Central Fabrication : The number of days betweensending the CAD file and receiving the insert . This isnot applicable to conventional inserts.On-Site Fabrication: The time required to digitize,modify and mount a CAD/CAM insert (i .e ., all tasksperformed by the on-site technicians/clinicians) . Forconventional inserts, this referred to the clinician andtechnician time required to make the insert.Final Fitting : The time required to fit and dispense acompleted insert.

Figure 2 shows central fabrication times for theCAD/CAM group . These data were sorted by the dateon which the seat and mounting hardware (if required)were received from the manufacturing facility . Oneextreme case was not representative of the regularcentral fabrication process and was removed from thedata set (110 day time lag) . The average time lag forcentral fabrication was over the initial estimate of 14days . Fabrication times using the CAD/CAM systemwere significantly faster than the manual modificationgroup (p

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20 .0%

33 .3%

•Redone

Intermediate changes =Minor changesNo changes

Figure 3.Clinician satisfaction as a percentage of the total number ofresponses for CAD/CAM and conventional seating inserts (itemdefinitions are in Table 2).

graphics of final shape, central fabrication, and so forth)would support continued use of the computerizedapproach.

While there were no statistical differences for clientand clinician satisfaction, differences were shown in thedescriptive data (Figure 4) . The hand-carved insertswere generally perceived as more comfortable . Thisresult was based on five CAD/CAM inserts having acomfort rating of fair while all manual inserts were ratedas good. Upon reviewing clinician comments for the fivefair inserts, in two cases the clinician had to makeadditional insert modifications and in one the clinicianconsidered the foam too hard . These factors are directlyrelated to client comfort. Since the cases with fair ratingswere some of the first inserts produced (i .e ., within thefirst five cases from each center), the lower perceivedcomfort can be related to clinical inexperience with theCAD/CAM system and foam density selection . Themethods used to modify a central fabrication insert mayalso contribute to insert comfort . If an area on theCAD/CAM insert has to be built up, the difference infoam densities may be unsettling to the client.

Generally, the same CAD/CAM seats that wererated fair for comfort were rated fair for design andappropriateness . This result could have occurred be-cause a client considered a fairly comfortable seat to beonly a fair design and/or because additional modifica-tions to these seats implied a design problem. In onecase, problems adjusting a pelvic belt could be the mainreason for the fair design rating . These seating insertswere within the first five cases: the necessity ofincluding at least five clinical trials as part of thetraining process should be considered when implement-ing a seating CAD/CAM system .

It was not surprising that the CAD/CAM insertswere generally considered more durable, since centralfabrication inserts were of a uniform density and had alatex covering sealed to the foam. These qualities gavethe inserts both a functional and visual perception ofdurability, especially since the client could see the baseinsert when the removable cover was off . None of theseating inserts have been returned or required replace-ment because of wear.

Most CAD/CAM inserts did not require additionalmodifications when received from the central fabrica-tion facility . Of the seats that required modifications,the majority were manufactured at the beginning of thestudy and their deficiencies could be attributed to theproblems of learning how to interact with a two-dimensional CAD image of a 3-D shape, refining thebead bag molding and client assessment process toimprove digitization, and needed improvements of theearly CAD software . Recent versions of the OBSSprovide 3-D views and on-screen measurement capabili-ties that help the clinician discover digitizing errorsbefore the shape is transmitted to the central fabricationfacility . Editing options for the insert's trim line andcutting plane were also added over the course of thisproject . While these features were not required duringthe study, it is anticipated that they will be very usefulin the future.

Two CAD/CAM inserts required reassessment andresubmission to the fabrication facility . These insertswere redone since the insert dimensions did not matchthe chair and substantial changes to the shape wererequired before fitting . Since there was a discrepancybetween the disk file and the insert shape, the cause ofthese problems could have been modem communicationerrors, file labelling errors at the fabrication site, ordigitization errors . As metal can disrupt the magneticfield of the digitizer, it is important to set up thecomputer system in an open area and check the initialcalibration to ensure accurate results. The clinician'sexperience with interpreting a 3-D image can also affectthe final product. Initially, clinicians with little CADexperience can have difficulty translating a flat-screenwireframe and/or shaded representation into a mentalimage of the 3-D shape . This difficulty may cause theclinician to miss some digitizing errors when evaluatingan on-screen CAD shape.

The time required to make a CAD data file waswell within expected limits, considering that this timeincluded a full patient fitting using a vacuum bag . Atthe start of the study, it was anticipated that the

Conventional

1 .1%

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60

50

0ao:0

40

30

20

10

0

50

4o§.m

30

20

10

0Excellent

Good

Fair

Excellent

Good

Fair

Comfort

Design

RCAD/CAM

Manual

Excellent

Good

Fair Excellent

Good

Fair

70

60

50

40

30

20

10

0

Durability

Appropriateness

Figure 4.

Client satisfaction ratings for CAD/CAM and manually manufactured seats as a percent of the total number of responses.

CAD/CAM and manual fabrication fitting times wouldbe similar . A benefit of the bead bag approach overhand sculpting was that by pre-molding the bead bag toan approximation of the seat shape before the client wastransferred to the fitting chair, fewer people wererequired to hold him/her in position during initial fittingand he/she did not have to be physically moved as oftenas with some conventional methods . These benefits aredirectly related to the bead-bag fitting process alone.Hand sculpting has the advantage of not requiringspecialized equipment to obtain shape measurements.

Since a central fabrication center was used toproduce the CAD/CAM insert, it was not unexpectedthat the manually produced seats required significantlymore technical time to be fabricated and mounted.

While the technical fabrication component was verysatisfactory, the time lag for central fabrication was wellover our criterion of 14 days . In addition, the lineartrend for fabrication increased during the study . Theseat/mounting hardware delivery process may have beeninfluenced by the transfer of manufacturing facilitiesfrom Canada to the United States during the final stagesof this project . To provide optimal service to the client,fabrication facilities should aspire to a delivery periodof from 5 to 10 working days. Current prostheticCAD/CAM fabrication times vary from 24 to 48 hours.Since the insert shape is stored digitally, the implemen-tation of a more efficient computer-controlled manufac-turing processes should not influence current clinicalCAD/CAM methods .

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CLINICAL REPORT: CAD/CAM System for Custom Seating

The clinical/technical time for production of a highcontour seating insert was greatly reduced by using theCAD/CAM system (average difference of 16 .3 hoursbetween CAD/CAM and conventional methods) . Thistime savings can be used to spend more time with eachclient or to work on other seating systems . 'While timesavings are beneficial to the seating clinician, the timedelays for central fabrication did not produce servicebenefits for the client . An improvement in this fabrica-tion time was the primary concern of the cliniciansinvolved with this study.

While CAD/CAM is an effective approach, thehand-carved method can produce a seating insert forless cost than most central fabrication options . Providedthat the seating technician has the skill to produce anacceptable product, a hand-carved insert can be pro-duced with minimal equipment and raw materials . Thecost effectiveness of using CAD/CAM versus manualfabrication will rely on the local economics (i .e ., costper device, cost of materials, and so forth), number ofreferrals, and clinical/technical skill . If hand-carvedinserts take an average of 12 .5 hours more to produce,this time could be used to make two or three simpleseating inserts . Depending on the local economics and acontinuous workload, this added productivity couldoffset the increased cost of CAD/CAM fabrication . Incontrast, a facility with technical expertise but littlework could financially benefit by letting the seatingclinicians and technicians spend the additional time tofabricate and fit a hand-sculpted insert . At The Rehabili-tation Centre, OBSS is only used for complex seatingcases, since it is more economical and faster to make asimple seating insert using manual methods . Also ofnote is that patient funding for CAD/CAM inserts in ourprovince has been cut to approximately 50 percent ofthe funding for traditionally produced, complex seatinginserts . This may be in recognition of the increasedefficiency of the CAD/CAM process.

A summary session with the participating clini-cians and technicians provided valuable qualitativeinsight into clinical application of the OBSS CAD/CAMsystem. The CAD/CAM bead bag method was effectivesince this approach did not introduce time constraints onthe therapists during the initial fitting process . Thera-pists at The Rehabilitation Centre often observed whatthey affectionately teiin the sleep test during fitting : if aclient falls asleep or visibly relaxes while sitting in themolded bead bag, the seat could be considered comfort-able. This test was very useful for clients who havedifficulty communicating .

Digitizing the bead bag with a stylus provided agood representation of the shape without having toeliminate wrinkles in the bead bag . One digitizingimprovement would be the inclusion of a button on thedigitizing stylus to replace the current method ofclicking the left mouse button of the computer . TheCAD software could be improved by adding more shapeediting tools and improving the graphical representationof the seating insert.

Use of a central fabrication facility provided abetter quality foam cushion than is often available in aclinical manufacturing environment (fewer air bubbles,more consistent density, and so forth) . This approachalso eliminated the use of toxic, foaming chemicals inthe clinic . The stored insert shape was useful for solvingdiscrepancies during fabrication, since the clinician cansee the image on screen while talking to the remotetechnician . Also, the clinician did not have to worry thathis only client mold has been sent through themail/courier to the manufacturing facility . A potentialfor alignment problems when a plaster cast is used forcentral fabrication was also reduced . The CAD/CAMsystem was very portable and ideal for clinics outsidethe regular seating area.

The following potential uses for seating CAD/CAM system were described by the participatingclinicians and technicians (these items were not appliedduring this study):

1. Second insert can be fabricated at a reduced cost(i .e ., no clinical time) for use in another chair or asa replacement once the old seat has worn out.

2. The CAD system can be used as a fitting tool insimple cases where the seating insert will bemanually carved from foam. By using the beadbag during the fitting process the clinician willhave a better idea as to the appropriateness of theseating design . After digitizing the bags, a recordof the complete shape is stored on disk . Measure-ments for fabricating the final seat can be takendirectly off the screen, thereby reducing the chanceof missing important measurements during theinitial assessment session . This technique can alsobe of benefit in cases where the clinical andtechnical staffs are at different locations (i .e .,remote site and fabrication center).

3. The digitized seat shape can be used with acomputerized video conference system to shareclinical information between clinics .

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4. Once a better file storage/retrieval/analysis methodhas been developed, the CAD/CAM system shouldprovide the clinician with a superior client record.

CONCLUSION

CAD/CAM is an effective and clinically efficientmeans of producing a custom seating insert . The majorbenefits of this technique over hand-carved seatinginserts are a reduced initial fitting time, reducedtechnical time during fabrication, and a reduced clinicaland technical time for seat fabrication . Areas ofimprovement for seating CAD/CAM include reducingthe time required for central fabrication, adding moreshape editing tools to the CAD software, and improvingthe seating insert's graphical representation. Furtherresearch involving CAD/CAM comparisons with otherseating insert fabrication methods is recommended.

ACKNOWLEDGMENTS

The authors would like to acknowledge the clinicaland technical support of Edward Shackles (The Reha-bilitation Centre) ; Malcolm Macintosh, Terry Steele,Monica Nagy (Rideau Regional Centre) ; and Francine

Dussault, Cyrille Ivanoff, Denis Lefebvre, Gilbert Par-ent (Centre Lucie Bruneau).

REFERENCES

1. Hulme JB, Gallacher K, Walsh J, Niesen S, Waldron D.Behavioral and postural changes observed with use ofadaptive seating by clients with multiple handicaps . Phys Ther1987 :67(7) :1060-7.

2. Nelham RL. Principles and practice with the manufacture ofseating for the handicapped . Physiotherapy 1984 :70(2) :54-8.

3. Ferguson-Pell MW . Seat cushion selection . J Rehabil ResDev, Clin Suppl 1990 :2 :49-73.

4. Colbert AP, Doyle KM, Webb WE . DESEMO seats for youngchildren with cerebral palsy . Arch Phys Med Rehabil1986 :67(7) :484-6.

5

Bardsley GI . The Dundee seating program. Physiotherapy1984 :70(2) :59-63.

6. Otto Bock Orthopaedic Industry of Canada Ltd . Customseating : custom cushion fabrication manual . Winnipeg,Manitoba, 1990.

7. Weishaupt W-A. Improvement of seating comfort due to anew wheelchair seat system. Int J Rehabil Res 1987 :10(4)(suppl 5) :90-9.

8. Sprigle S, Chung K, Brubaker CE . Factors affecting seatcontour characteristics . J Rehabil Res Dev 1990 :27(2) :127-134.

9. Polhemus. 3SPACE User's Manual . Colchester, VT, 1992.10. Lemaire ED, Upton D. Clinical factors for seating CAD/CAM

application (Abstract) . In: Canadian Seating and MobilityConference, Toronto, Ontario, 1993 .

Clinical Analysis of a CAD/CAM System for Custom Seating: A Comparison with Hand-Sculpting MethodsEdward D. Lemaire, MSc; David Upton, BSc; Joseph Paialunga, BScOT(C); Guy Martel, MHSc, CPO(C); Jacques BoucherThe Rehabilitation Centre, Ottawa, ON, Canada KIH 8M2; Centre de Readaptati.on Lucie Bruneau, Montreal, PQ,Canada H2H 2N8

INTRODUCTIONMETHODSRESULTSDISCUSSIONCONCLUSIONACKNOWLEDGMENTSREFERENCES

clinical analysis of a cad/cam system for custom seating: a … · 2005. 8. 23. · cad/cam seats...

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