Development of a postural support device for crosstable radiography of the extremities

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. Radiographers have traditionally used a chair, stacks of soft pads, an individual, 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 hospitals. 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 survey contributed to a needs analysis for consideration of marketing the device.


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 fractures or dislocations of the hip joint include the antero-posterior projection of the pelvis and the cross-table  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. Radiographers 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 hospitals. 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 survey contributed to a needs analysis for consideration of marketing the device.

Results
Forty-one (79.5%) of the 54 questionnaires 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 respondents did not have to repeat the radi-

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 wearing 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) motional unsharpness due to discomfort experienced by the patient.

Solution
During 1996 the idea of a leg support 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, occupational therapists, orthopaedic surgeons and plastic surgeons can also 38 SA JOURNAL OF RADIOLOGY • September 2002    use the device when fitting appliances, traction or dressings.

Outcomes
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