range-of-motion restriction and craniofacial tissue-interface pressure from four cervical collars

Range-of-Motion Restriction and Craniofacial Tissue-Interface Pressure From Four Cervical CollarsAnn N. Tescher, RN, PhD, CNS, Aaron B. Rindflesch, PT, James W. Youdas, PT,Therese M. Jacobson, RN, CNS, Lisa L. Downer, RN, CNS, Anne G. Miers, RN, CNS,Jeffrey R. Basford, MD, PhD, Daniel C. Cullinane, MD, Susanna R. Stevens, MS, V. Shane Pankratz, PhD,and Paul A. Decker, MS

Background: Occipital pressure ul-cers are well-known complications fortrauma patients wearing cervical collars.We assessed the effects of four commercialcervical collars (Aspen, Philadelphia, Mi-ami J, and Miami J with Occian back[Miami J/Occian]) on cervical range ofmotion (CROM) and mandibular and oc-cipital tissue-interface pressure (TIP).

Methods: Forty-eight healthy volun-teers (24 men, 24 women; mean age, 38.9years � 10.5 years) were stratified by bodymass index. Seated subjects were measuredwithout and with collars. Sagittal, coronal,and rotatory CROM was measured with agoniometer. Occipital and mandibular pres-

sures were mapped with subjects in uprightand supine positions.

Results: All collars significantly re-stricted CROM in all planes (p < 0.001).The Philadelphia and standard Miami J col-lars were the most restrictive. The Aspencollar was the least restrictive for flexionand rotation. The Miami J/Occian back wasthe least restrictive for extension and lateralflexion. For supine measurements, Miami Jand Miami J/Occian back had the lowestmean TIP, whereas Aspen and Philadelphiacollars had the greatest (p < 0.001). Forupright measurements, the Miami J/Occianback produced the smallest mean TIPs; theother collars, ranked by ascending TIP,

were Philadelphia, Miami J, and Aspen(p < 0.001). Philadelphia and Miami J col-lars had significant collar-body mass indexinteraction effects on supine occiput meanpressure (p � 0.04).

Conclusions: Miami J and Philadel-phia collars restricted CROM to thegreatest extent. Miami J and Miami J/Oc-cian back had the lowest levels of mandib-ular and occipital pressure; these collarsmay markedly reduce the risk of occipitalpressure ulcers without compromising im-mobilization.

Key Words: Cervical collar, Pressureulcer, Range of motion, Tissue-interfacepressure.

J Trauma. 2007;63:000–000.

Occipital pressure ulcers are well-known complications thatresult from prolonged use of rigid cervical collars.1–4

Pressure on occipital tissue as a result of immobility,decreased level of consciousness, or hypoesthesia is the mostcrucial factor.2 Impaired perfusion, shifts that occur withresuscitation, poor collar fit, shear forces, and diaphoresis allmay have an effect.2 Although many factors cannot be con-trolled or eliminated, the pressure exerted against occipitaltissue by the cervical collar may be ameliorated.

The American College of Surgeons Advanced TraumaLife Support course for physicians recommends use of a rigidcervical collar and backboard to immobilize the cervical

spine of trauma patients until fracture or ligamentous injurycan be excluded.5 However, if a patient cannot be evaluatedadequately because of an altered mental status or other inju-ries, the collar is usually kept in place until a definitiveevaluation can be performed. In a study by Davis et al.,3 55%of patients who wore a cervical collar for 5 or more days haddevelopment of full-thickness occipital ulcers.

The aims of our study were to compare the degree towhich each of four commercially available hard cervicalcollars restricted normal cervical range of motion (CROM)and to assess tissue-interface pressure (TIP) exerted by thecollars in the upright and supine positions. Our goal was todetermine which of these collars would have the minimumTIP and the most restriction of CROM.

PATIENTS AND METHODSSubjects

Fifty-three healthy volunteers between 18 and 60 years ofage were recruited for the study after approval was obtainedfrom the Mayo Clinic Institutional Review Board. Prospectivesubjects were screened for neck pain, history of spinal surgery,physical or chiropractic therapy to the neck, history of necktrauma requiring medical care, and history of cervical spondy-losis or osteoporosis. Five prospective subjects were excluded,and the remaining 48 were stratified by body mass index (BMI)(20–24.9 kg/m2, 25–30 kg/m2, or �30 kg/m2) into three groupsof eight women and eight men each.

Submitted for publication June 19, 2006.Accepted for publication February 8, 2007.Copyright © 2007 by Lippincott Williams & WilkinsFrom the Department of Nursing (A.N.T., T.M.J., L.L.D., A.G.M.);

Department of Physical Medicine and Rehabilitation (J.R.B.); Division ofTrauma, Critical Care, and General Surgery (D.C.C.); Division of Biostatis-tics (S.R.S., V.S.P., P.A.D.), Mayo Clinic; and the Physical Therapy Program(A.B.R., J.W.Y.), Mayo School of Health Related Sciences, Mayo ClinicCollege of Medicine, Rochester, Minnesota.

Nothing in this article implies endorsement of the products of PhiladelphiaCervical Collar Company, Aspen Medical Products, or Jerome Medical.

Address for reprints: Ann N. Tescher, RN, PhD, Department of Nurs-ing, Mayo Clinic, 200 First Street SW, Rochester, MN 55905; email:[email protected].

DOI: 10.1097/TA.0b013e3180487d0f

balt5/zta-ta/zta-ta/zta01107/zta9971-07z xppws S�1 9/18/07 13:25 Art: TA201667 Input-4b

The Journal of TRAUMA� Injury, Infection, and Critical Care

Volume 63 • Number 5 1

AQ: 1AQ: 1

<zjs;Original Article> • <zjss;Original Article> • <zdoi;10.1097/TA.0b013e3180487d0f>

OrthosesWe assessed four collars. The Philadelphia (Philadelphia

Cervical Collar Company, Thorofare, NJ), Aspen (AspenMedical Products, Irvine, CA), and Miami J (Jerome Medi-cal, Moorestown, NJ) collars are designed to provide neckimmobilization for long-term acute and rehabilitation phasesof patient care. The Miami J collar with Occian back (MiamiJ/Occian) (Jerome Medical) is recommended for patients whorequire cervical immobilization, prolonged supine position-ing, and have a high risk of occipital skin breakdown.6 TheMiami J/Occian back uses the anterior half of the Miami Jcollar, and the posterior Occian component is composed ofmaterials that conform to the occiput, maximize the area ofskin contact, and soften when warmed by the patient’s ownbody heat.2,6

MeasurementsSubjects were weighed, and their height was measured

using a calibrated standing scale. Three nurses with expertisein collar use measured and fit the subjects according to themanufacturer’s instructions. The four collars were assessed inrandom order.

All CROM measurements were taken by the same expe-rienced physical therapist (J.W.Y.) using a CROM device(Hospeq, Miami, FL).7 The device consists of a plastic framemounted over the subject’s nose bridge and ears and securedto the head with a Velcro strap. Neck flexion, extension, andlateral flexion movements are recorded by two gravity goni-ometers marked in two-degree increments. The cervical ro-tation was assessed in a similar manner with a compassgoniometer that is used with a shoulder-mounted magneticyoke. Goniometric measurements correlate closely withroentgenographically determined cervical motion.8 TheCROM device is accurate,9 easy to use, and has a highintraclass correlation coefficient (0.83–0.95)10 when com-pared with a universal goniometer or visual estimation. Thesame device was used throughout the study in the manneroutlined in Table 1. CROM was measured only when patientswere seated because the CROM device inclinometers for thesagittal and frontal planes rely on gravity.

TIP was measured simultaneously over the occiput andboth mandibles by a highly experienced physical therapist(A.B.R.) using three custom-sized pads of the XSENSOR X2System (XSENSOR Technology Corporation, Calgary, Al-berta, Canada). The XSENSOR system consisted of a squaregrid of capactive pressure-sensing transducers (resolution,0.64 cm2) embedded in three mats (7.5 � 12.5 � 0.1 cm)placed between the cervical collar and the subject’s mandibleand occiput. Pressure between 0 mm Hg and 220 mm Hg maybe sensed. The mats are connected to a laptop computer thatpermits data viewing in two or three dimensions and indistribution histograms; data may be shown as mean pressureversus time, peak pressure versus time, and contact areaversus time. For measuring pressure over curved surfaces, thesystem is highly accurate (2% error) when compared with

resistive ink technology systems such as the F-scan system.11

Calibration was performed before measuring each subject inaccordance with the manufacturers’ instructions.12 TIPs weremeasured using the protocol described in Table 2.

Data AnalysisData were analyzed using repeated-measures analysis of

variance. The univariate single-group repeated-measures analy-sis of variance used the Greenhouse-Geisser correction to nom-inal degrees of freedom with a sample size of six and p � 0.05.This significance level had 80% power to detect a difference inmeans across the levels of the repeated measures factor and wascharacterized by an effect size of 4.3405. This scenario assumed

Table 1 Protocol for Cervical Range of Motion(CROM) Measurements

1. The subject was seated in an aluminum-frame chair. Thethoracic spine maintained contact with the chair’s backrest, andthe lumbosacral spine filled the gap between the seat and thebackrest. The subject’s feet were flat on the floor, and thesubject’s arms rested freely on the sides.

2. A nurse investigator measured and fit each subject with 4cervical collars, according to manufacturers’ instructions. Collarswere chosen in random order. The CROM device was mountedover the subject’s nose bridge and ears and secured to thehead with a Velcro strap, according to the manufacturer’sinstructions.

3. As instructed by the physical therapist investigator, each subjectperformed 3 repetitions of neck flexion, extension, left and rightlateral flexion, and left and right rotation, in that order, toincrease compliance of the soft tissues of the neck. The subjectwas instructed to move the head until the CROM in flexion,extension, lateral flexion to left and right, and rotation to the leftand right was stopped by muscle tightness, pain, or until asubstitution movement occurred.

4. The tester measured the subject’s CROM in both directionswithin a cardinal plane using the CROM device. The starting andend points of the CROM were recorded. Immediately after thefirst 6 measurements, the tester removed the CROM apparatusfrom the subject and repositioned it on the subject. The subjectrepeated the series of movements, providing 2 sets of 6measurements.

Table 2 Protocol for Tissue-Interface PressureMeasurement

1. The subject was seated, and XSENSOR pads were placed onthe anterior mandibles and occiput. The subject was fit with aproperly sized cervical collar by a nurse investigator. Collarswere chosen in random order.

2. Although the subject was seated, pressure measurements anddistribution of pressure (“pressure map”) on the anteriormandibles and occiput were recorded by one of the physicaltherapist investigators.

3. The subject was placed in a supine position on a standardhospital bed mattress without a pillow. Pressure measurementsand distribution of pressure (“pressure map”) at the mandiblesand occiput were noted. Collars were evaluated in the sameorder as the upright seated evaluation. The subject wasinstructed to notify investigators of any discomfort while supine.



2 November 2007

T1

T2

a mean TIP of 95 mm Hg � 6 mm Hg without a collar and 125mm Hg � 10 mm Hg with a collar. The data used in thiscalculation were taken from the study by Bridges et al.12

RESULTSCROM

Baseline measurements without a collar showed that allsubjects had normal CROM in all directions.9,10,13 All collarsproduced a statistically significant restriction of movement(p � 0.001). Measurement reliability was confirmed withintraclass correlation coefficients greater than 0.6 in allmovement planes (Table 3).

Of the four collars, the Philadelphia was the most restrictiveof CROM in all movement planes (p � 0.001), followed by the

Miami J. The difference in restrictiveness between the Philadel-phia and Miami J collars in all movement planes was notstatistically significant. The Aspen collar was the least restric-tive of flexion and rotation, and the Miami J/Occian back wasthe least restrictive of extension and lateral flexion move-ments. The pairwise comparisons of the collars (to each otherand to CROM without a collar) are shown in Table 4.

TIPTIP was measured along both mandibles and the occiput

with the subjects sitting upright and lying supine without apillow on a standard hospital bed. The Aspen collar had thehighest mean TIP on both mandibles and occiput in theupright and supine positions (p � 0.001). The Philadelphia

Table 3 Intraclass Correlation Coefficients for Cervical Range of Motion Measurements

No Collar Philadelphia Aspen Miami J Miami J WithOccian Back

Flexion 0.859 0.790 0.609 0.939 0.902Extension 0.981 0.928 0.876 0.973 0.980Right lateral flexion 0.935 0.953 0.951 0.961 0.955Left lateral flexion 0.955 0.963 0.973 0.957 0.966Right rotation 0.874 0.953 0.973 0.942 0.970Left rotation 0.977 0.959 0.951 0.962 0.946

Table 4 Extension, Flexion, Lateral Flexion, and Rotation With Four Cervical Collars

Movement No Collar*

Collar Type

Aspen Philadelphia Miami J Miami J WithOccian Back

Mean P Mean P Mean P Mean

Extension, degrees† 70.98 � 10.00 26.87 � 13.71 0.03‡ 23.26 � 11.58 0.15§ 25.65 � 11.49 �0.001� 31.40 � 12.990.46¶ �.001#0.007**

Flexion, degrees† 48.92 � 7.91 16.97 � 8.74 �0.001‡ 11.67 � 6.53 0.44§ 12.57 � 6.79 0.57� 13.22 � 6.86�0.001¶ 0.18#

0.001**Lateral flexion, degrees†

Right 39.89 � 6.01 24.50 � 9.90 0.03‡ 21.93 � 10.00 0.10§ 23.85 � 10.16 0.02� 26.65 � 9.050.58¶ �0.001#0.07**

Left 39.76 � 6.64 23.42 � 9.24 0.03‡ 20.88 � 10.16 0.14§ 22.63 � 9.53 0.02� 25.39 � 8.930.50¶ �0.001#0.09**

Rotation, degrees†Right 67.92 � 6.97 24.81 � 13.45 0.003‡ 20.09 � 12.31 0.05§ 23.08 � 11.38 0.96� 23.00 � 11.59

0.26¶ 0.06#0.24**

Left 68.16 � 8.66 26.89 � 14.41 0.01‡ 22.59 � 13.01 0.10§ 25.40 � 11.76 0.58� 26.34 � 13.560.38¶ 0.03#0.75**

* P � 0.001 for all pair-wise comparisons.† P � 0.001 for all overall comparisons.‡ Aspen versus Philadelphia.§ Philadelphia versus Miami J.� Miami J versus Miami J with Occian back.¶ Aspen versus Miami J.# Philadelphia versus Miami J with Occian back.** Aspen versus Miami J with Occian back.


Evaluation of Four Cervical Collars


T3

T4

collar had the highest maximal TIP on the occiput in thesupine position (p � 0.001). The Miami J/Occian back hadthe lowest mean TIP on the occiput in the upright and supinepositions, and on both mandibles in the supine position. Themean and maximal pressures exerted by each collar in theupright and supine positions are shown in Figures 1 and 2.

We categorized the 48 subjects by BMI and sex tocontrol for the effect of body size on mobility and TIP. Wefound a significant association between BMI and the meansupine occiput pressure overall (p � 0.04).

DISCUSSIONCROM

To our knowledge, no studies have combined measure-ments of restrictiveness (i.e. CROM) and tissue pressureswhen examining cervical collars. Ducker (Ducker TB, read at

American Association of Neurologic Surgeons, Nashville,TN, 1990), Mosenkis,14 and Lunsford et al.15 compared therestrictive ability of cervical collars. These investigatorsfound that all collars were restrictive when compared withreference values but reached different conclusions about thecomparative restrictiveness of individual collars. The mostlikely reason for the different conclusions is that differentmeasurement devices were used with each study. Our choiceof the CROM device was made on the basis of its ease of useand measurement reliability.10

With three video cameras, Lunsford et al.15 measuredcervical motion in 10 subjects using a pointer attached to amouth stick. The fit of each collar (Philadelphia, Miami J,Malibu, and Newport extended wear) was standardized withan elastic tensiometer. Zhang et al.16 compared four collars(Aspen, XTW, C-Breeze, and Miami J) with 20 subjects.

Fig. 1. Tissue-interface pressure, mandible. Capillary closing pressure is 32 mm Hg (solid line). (A) Mean right mandible pressure, uprightposition. (B) Mean left mandible pressure, upright position. (C) Mean right mandible pressure, supine position. (D) Mean left mandiblepressure, supine position.



4 November 2007

F1–2

They used a sophisticated three-camera motion analysis sys-tem in a biomechanics laboratory to obtain three-dimensionalkinematic data from each subject. Although measurements inthat study were precise, we chose a technique that would bemore readily used by clinicians.

Mosenkis14 and an unpublished abstract by Ducker(Ducker TB, read at American Association of NeurologicSurgeons, Nashville, TN, 1990) used the CROM goniometerdevice to measure cervical motion restriction. Mosenkis stud-ied 20 subjects and compared the Philadelphia, Aspen, andMiami J collars; Ducker studied five collars (soft foam,Philadelphia, Stifneck, NecLoc, and Miami J) in 35 subjects.One limitation of the Mosenkis study is that the degrees oflateral flexion and axial rotation to the left and right weresummed rather than reported separately, which precludedtesting of motion symmetry.

TIPAlthough cervical collar TIP was the variable of most

interest in the formation of pressure ulcers, collar restrictive-ness was the outcome variable of utmost importance forclinical practice. Although individual factors may have someaggravating or relieving influence, an external pressure of 25mm Hg to 32 mm Hg generally causes capillary compression.12

Bader and Gant17 and Colin and Saumet18 showed a directassociation between vascular perfusion and tissue oxygentension by measuring a 50% decrease in transcutaneous ox-ygen after applying external pressure as low as 22 mm Hg.Whether external pressure is of low intensity and long dura-tion or high intensity and short duration, unrelieved pressureultimately may cause tissue ischemia and cell necrosis. Themaximal supine occiput pressure for all collars (range, 44.21–103.7 mm Hg [Miami J/Occian back and Philadelphia, re-spectively]) was well above the capillary closing pressure of

32 mm Hg. However, the mean supine occiput pressures in allcollars (range, 26.92–38.56 mm Hg [Miami J/Occian backand Aspen, respectively]) were much lower because meanpressure is a function of total surface area of contact. Severalauthors have associated wearing a cervical collar with occipitalpressure ulcer formation,1,19–23 but their studies were descrip-tive, predictive, or focused on the process of product change.

The ability to measure the effect of a hard cervical collaron occipital TIP clearly has been hampered by the lack ofmeasuring devices that were reliable but still small and pli-able enough to fit between the head and collar. We are awareof only two studies that examined the effect of pressureexerted by cervical collars on the skin.2,8 One by Fisher et al.8

included eight subjects and used an infant sphygmomanom-eter at the chin and occiput to measure pressure during flex-ion and extension. The Fisher study aimed to determinewhether a cervical collar could be fitted to more tolerablepressures while still providing adequate immobilization.Plaisier et al.2 compared four collars (Stifneck, Philadelphia,Newport, and Miami J) with 20 subjects and used one elec-tropneumatic sensor that needed to be repositioned to mea-sure skin-collar interface pressures on the occiput, mandible,and chin. Despite the differences in measurement techniques,their TIP findings for the Philadelphia and Miami J collarswere similar to ours.

The mapping system used in our study provided severaladvantages. First, the pressure mapping pads were small andpliable enough to fit easily inside each collar. Second, thesensor pads were able to cover the occiput and mandiblessimultaneously and repositioning was unnecessary. Third, thesensor pads reliably measured pressure over curved surfaces.

BMI had a significant effect on TIP only for the Phila-delphia and Miami J collars (Fig. 3). The association betweenBMI and TIP was contrary to the findings of other pressure

Fig. 2. Tissue-interface pressure, occiput. Capillary closing pressure is 32 mm Hg (solid line). (A) Mean occiput pressure, upright position.(B) Mean occiput pressure, supine position.




F3

mapping studies24–27 that often show lower BMIs associatedwith higher TIPs, usually because of lack of muscle or adi-pose tissue mass over bony prominences. In our study, sub-jects with BMI more than 30 kg/m2 had higher average TIP,which we attribute to greater weight without greater tissuemass on the skull.

Our study had several potential limitations. Use ofambulatory adults as a model for CROM and TIP may havelimited application for acutely injured trauma patients. Thetraumatic inflammatory response leads to retention of fluidand tissue edema, which further exacerbate the effects ofpressure on tissue ischemia. Also, factors such as moisture,poorly fitting collars, and shear forces that may increasethe risk of pressure ulcer formation were not examined.

CONCLUSIONThe results of our study of uninjured, healthy adults

indicate that the Philadelphia and Miami J collars effec-tively reduced cervical movement, and the Miami J collarwith and without the Occian back provided superior pres-sure relief. Consequently, the Miami J collar may be theorthosis of choice for trauma patients who are admitted tothe hospital. Because the Miami J/Occian back was theleast restrictive in cervical extension, we use it for occip-ital support for patients with strict spine precautions andpatients who are exclusively bedridden.

ACKNOWLEDGMENTSWe thank the Section of Scientific Publications, Mayo Clinic, for

editing, proofreading, and reference verification.

REFERENCES1. Blaylock B. Solving the problem of pressure ulcers resulting

from cervical collars. Ostomy Wound Manage. 1996;42:26 –28,30, 32–33.

2. Plaisier B, Gabram SG, Schwartz RJ, et al. Prospective evaluation ofcraniofacial pressure in four different cervical orthoses. J Trauma.1994;37:714–720.

3. Davis JW, Parks SN, Detlefs CL, et al. Clearing the cervical spine inobtunded patients: the use of dynamic fluoroscopy. J Trauma. 1995;39:435–438.

4. Agency for Health Care Policy and Research. Preventing PressureUlcers. Rockville, MD: US Department of Health and HumanServices Public Health Service; 1992. AHCPR Publication No. 92-0048. [cited May 18, 2006]. Available at:www.woundheal.com/healing/patientGuideMain.htm.

5. Chendrasekhar A, Moorman DW, Timberlake GA. An evaluation ofthe effects of semirigid cervical collars in patients with severe closedhead injury. Am Surg. 1998;64:604–606.

6. Jerome Cervical Spine System [homepage on the internet].Continuum of Care Products: Occian Back. Moorestown, NJ:Jerome Medical Inc; c2000–2005 [cited Dec 14, 2005]. Available at:www.jeromemedical.com/occianback.php.

7. rehaboutlet.com [homepage on the internet]. Range of MotionMeasurement. Miami: Hospeq Inc; c1999–2006 [cited Nov 18,2004]. Available at: www.rehaboutlet.com/range_of_motion_measurement.htm.

8. Fisher SV, Bowar JF, Awad EA, et al. Cervical orthoses effect oncervical spine motion: roentgenographic and goniometric method ofstudy. Arch Phys Med Rehabil. 1977;58:109–115.

9. Youdas JW, Garrett TR, Suman VJ, et al. Normal range of motionof the cervical spine: an initial goniometric study. Phys Ther. 1992;72:770–780.

10. Youdas JW, Carey JR, Garrett TR. Reliability of measurements ofcervical spine range of motion: comparison of three methods. PhysTher. 1991;71:98–104.

11. Fergenbaum M, Hadcock L, Stevenson J, et al. Pressuremeasurement applications for humans. Available at:www.anatomicsitt.com/produkter/xsensor/queensstudy.pdf. AccessedMay 18, 2006.

12. Bridges EJ, Schmelz JO, Mazer S. Skin interface pressure on theNATO litter. Mil Med. 2003;168:280–286.

13. Schoen DC. Adult Orthopaedic Nursing. Philadelphia, PA:Lippincott; 2000.

14. Mosenkis R. Comparison of Three Cervical Collars in RestrictingCervical Spine Motion [CITECH test report]. Moorestown, NJ:Jerome Medical; 2001:490–421.

15. Lunsford TR, Davidson M, Lunsford BR. The effectiveness of fourcontemporary cervical orthoses in restricting cervical motion. JProsthet Orthot. 1994;6:93–99.

16. Zhang S, Wortley M, Clowers K, et al. Evaluation of efficacy and3D kinematic characteristics of cervical orthoses. Clin Biomech(Bristol, Avon). 2005;20:264–269.

17. Bader DL, Gant CA. Changes in transcutaneous oxygen tension as aresult of prolonged pressures at the sacrum. Clin Phys Physiol Meas.1988;9:33–40.

18. Colin D, Saumet JL. Influence of external pressure ontranscutaneous oxygen tension and laser Doppler flowmetry onsacral skin. Clin Physiol. 1996;16:61–72.

19. Webber-Jones JE, Thomas CA, Bordeaux RE Jr. The managementand prevention of rigid cervical collar complications. Orthop Nurs.2002;21:19–25.

20. Black CA, Buderer NM, Blaylock B, Hogan BJ. Comparative studyof risk factors for skin breakdown with cervical orthotic devices:Philadelphia and Aspen. J Trauma Nurs. 1998;5:62–66.

21. Liew SC, Hill DA. Complication of hard cervical collars in multi-trauma patients. Aust NZ J Surg. 1994;64:139–140.

22. Powers J. A multidisciplinary approach to occipital pressure ulcersrelated to cervical collars. J Nurs Care Qual. 1997;12:46–52.

Fig. 3. Effects of body mass index (BMI) on mean supine occiputpressure. The interaction effect of the collar and BMI was signifi-cant (p � 0.04).



6 November 2007

23. Watts D, Abrahams E, MacMillan C, et al. Insult after injury:pressure ulcers in trauma patients. Orthop Nurs. 1998;17:84 –91.

24. Kernozek TW, Wilder PA, Amundson A, et al. The effects of bodymass index on peak seat-interface pressure of institutionalizedelderly. Arch Phys Med Rehabil. 2002;83:868–871.

25. Stinson MD, Porter-Armstrong A, Eakin P. Seat-interfacepressure: a pilot study of the relationship to gender, body mass

index, and seating position. Arch Phys Med Rehabil. 2003;84:405– 409.

26. Colin D, Loyant R, Abraham P, et al. Changes in sacraltranscutaneous oxygen tension in the evaluation of differentmattresses in the prevention of pressure ulcers. Adv Wound Care.1996;9:25–28.

27. Garber SL, Campion LJ, Krouskop TA. Trochanteric pressurein spinal cord injury. Arch Phys Med Rehabil. 1982;63:549–552.




JOBNAME: AUTHOR QUERIES PAGE: 1 SESS: 1 OUTPUT: Tue Sep 18 13:25:39 2007/balt5/zta�ta/zta�ta/zta01107/zta9971�07z

AQ1— Production Editor: Kindly check whether the disclaimer information is OK as given.

AUTHOR QUERIES

AUTHOR PLEASE ANSWER ALL QUERIES 1

range-of-motion restriction and craniofacial tissue-interface pressure from four cervical collars

Documents