SHORT REPORT

Development of a
postural support
device for cross-

table radiography of
the extremities

N Ebrahim
Nat Dip Rad (Diag), FETe (London),

MSc Radiography (Diag) (UK)

Department of Radiography
Medical University of Southern Africa

Introduction
A postural support device (*RSA

Registered Design Application No.
F2002/0033) was originally developed
to provide irnrnobilisation for patients
requiring cross-table radiography of
the hip joint. On further investigation
it was found that it had additional
applications, as discussed later.

Background
The routine projections for frac-

tures or dislocations of the hip joint
include the antero-posterior projec-
tion of the pelvis and the cross-table

Fig. te. Supine pelvis.

Fig. 1b. Cross-table lateral of the hip joint
demonstrating the femoral neck.

lateral projection of the neck of the
femur (Figs la and lb),

In order to demonstrate the neck
of the femur, the unaffected leg has to
be raised and supported. Radio-
graphers have traditionally used a
chair, stacks of soft pads, an individ-

ual, or the X-ray tube to support their
patients.

In 1998 a national survey, utilising
self-completing questionnaires was
conducted amongst 54 radiographers
working in public and private hospi-
tals. Respondents were required inter
alia to indicate the type of support
that they were using, the categories of
patients seen, what the repeat rate was
and whether they thought their
method of support was safe. This sur-
vey contributed to a needs analysis for
consideration of marketing the device.

Results
Forty-one (79.5%) of the 54 ques-

tionnaires were returned. They were
statistically analysed and revealed the
following information (Tables I - IV).

From the above results it can be
seen that a large percentage of adults
required radiography of the hip joint.
One practice had a specially designed
support but it was not height
adjustable. Whilst 56.1% of respon-
dents did not have to repeat the radi-

Table I. Patients most often/ equally
seen (rating = 1)

Category Percentage

Geriatrics 63.4
Adults 56.1
Juveniles 10.5
Infants 15.8

Table II. Method of support (combined figures)

Support Number Percentage

Box 14 34.1
Chair 9 21.9
X-ray tube 22 53.7
Assistant 18 43.9
Specially designed support 1" 2.4
~ Not height adjustable.

37 SA JOURNAL OF RADIOLOGY • September2002



SHORT REPORT

Table III. Repeat radiographs due to
poor support

Response Percentage

Yes
No

43.9
56,]

Table IV, Is your current support
safe?

Response Percentage

Yes
No

28.6
71.4

ographic projection, 71.4% of the
respondents did not regard their cur-
rent support as being safe.

Current problems'
A chair is: (l) cumbersome; (ii) not

height adjustable in most cases; and
(iit) difficult to place outside the area
of interest.

The leg on the X-ray tube means
that: (t) the patient feels insecure; (it)
the leg has to be shifted several times
when the height of the X-ray tube is
adjusted - patients may not be wear-
ing shoes and may sustain a burn to
the heel; and (iii) the foot is exposed
to radiation due to its close proximity
to the exiting beam.

An assistant has: (l) unnecessary
exposure to radiation; (it) back strain;
and (iii) difficulty experienced in
immobilisation.

Repeat
radiographs

The major contributing factors for
repeat radiographs are as follows: (t)
superimposition of the soft tissues of
the unaffected limb on the structure
being demonstrated; and (it) motion-
al unsharpness due to discomfort
experienced by the patient.

Solution
During 1996 the idea of a leg sup-

port was disclosed to the Research and
Ethics Committee of the Medical
University of Southern Africa. The
prototype was designed in 1997. The
device was tested at Ga-Rankuwa
Hospital's X-ray department. The
management of the university also
recommended that an application for
a design protection be lodged. The
final product was manufactured in
2002 (Figs 2a and 2b). Fig. 3 illustrates
the application of the device during
cross-table lateral radiography of the
hip joint. The device may also be used
during cross-table radiography of the
lower limb (Fig. 4), and cross-table
radiography of the shoulder (Fig. 5).

Versatility
Orthotists, prosthetists, occupa-

tional therapists, orthopaedic sur-
geons and plastic surgeons can also

38 SA JOURNAL OF RADIOLOGY • September 2002

Fig. 2b. Side view of the postural support
device. Note: The device is: lightweight (1.5 kg),
height adjustable (43 - 66 em), portable, safe
and aesthetically attractive.

Fig. 3. Positioning for cross-table lateral radi-
ography of the hip joint using the postural
support device.

Fig. 4. Positioning for cross-table lateral radio
ography of the lower leg.



SHORT REPORT

Fig. 5. Positioning for cross-table lateral radi-
ography of the humerus (axilla) us/ng the
postural support device.

use the device when fitting appliances,
traction or dressings.

Outcomes
The application for design protec-

tion through the Medical University
of Southern Africa resulted in: (i) the

compilation and institution of an
Intellectual Property Policy at the
Medical University of Southern
Africa; and (ii) the submission of a
Portfolio of Evidence entitled
'Intellectual Property - An Inventor's
Perspective' as partial fulfilment of a
MSc in Diagnostic Radiography
offered by the Anglia Polytechnic
University, Cambridge, United
Kingdom.

I would like to thank the manage-
ment of the Medical University of
Southern Africa for their support,
Professor H S Schoeman for his assis-
tance with the statistical analysis, Mr J
Van Loggenberg for the manufacture
of the prototype, Mr Grant Pywell of
ASG Medical Equipment Services for

his assistance in developing the device,
Mr Mike Von Seidelfor his assistancein
the application for Design Protection,
the management of the X-ray
Department Ga-Rankuwa Hospital for
allowing the trials to be conducted and
the student radiographers who assisted
with the photography of the device.My
thanks also go to the following depart-
ments at the Medical University of
Southern Africa: the Department of
Medical illustration and Audio-Visual
Services, the Department of Occupa-
tional Therapy and the Department of
Orthopaedics for their assistance in the
development and application of the
product.

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