Introduction - What's a PBM?

As part of the final year of study for a degree in Diagnostic Radiography, the students have to arrange a three week clinical placement in a hospital of their choice. The placement is intended to give the student an opportunity to investigate an area or aspect of diagnostic radiography that he/she finds particularly interesting. The module is assessed by means of the student writing a reflective journal about his/her learning experience during the placement and also a poster presentation demonstrating key learning points from the placement, i.e. applying theory to practice. To achieve this each student must set some learning objectives that are professionally relevant to the chosen area of interest. For my PBM, I have chosen to investigate the management of a patient suffering a fracture of the neck of femur. I have chosen my placement within a large, teaching hospital in the Midlands. In the interests of confidentiality the hospital, department, staff or patients will not be identified. My objectives for this module are as follows:
1. To explore the different types of fractures associated with sub-capital fracture and how a patient may present
2. To examine different treatment & management options for a patient with a fractured neck of femur
3. To investigate the different types of prosthesis used for fractured neck of femur

Friday, September 14, 2007

Protocols & Techniques

On Thursday morning I managed to image two NOF 's and thought it might be informative for you eager readers to know what actually happens. Here goes...

For trauma to the neck of femur department protocol at my PBM hospital is that first an anteroposterior (AP) of the pelvis is undertaken (see image below). The image should include the whole of the pelvis (including both hip joints), upper third of each femur and soft tissue outlines. All neck of femur trauma should be carried out on the trolley that the patient arrives on and if the injured limb is externally rotated it must not be moved.

When looking at the image the radiographer compares the injured side with the uninjured side. He/she assesses for normal trabecular pattern and that the cortex is intact. The pubic rami is also carefully assessed as if it is fractured it can mimic the sign and symptoms of a femoral neck fracture.

If a fracture is suspected then the department protocol states that a horizontal beam lateral of the affected hip should be undertaken. It also states that a pre-operative chest x-ray is undertaken at the same time if the patient is over 70 years old. The chest x-ray is to assess the patients health prior to operating.

Horizontal Beam lateral

When a fracture is suspected a second view must be achieved. With a trauma patient the affected leg cannot be moved so a horizontal beam lateral is performed. So what's involved? The standard procedure at this hospital (in A&E) is to use an air gap technique using the erect automatic exposure grid (AED). The patient is supine on the trolley with the affected limb extended (see diagram below). The trolley is positioned so that the median saggital plane (MSP) is 45 degrees to the cassette in the erect bucky. This brings the the neck of femur parallel to the cassette. The unaffected limb is raised onto a support so that it is not in the way of the primary beam. Apparently, the air gap between the patient and the cassette reduces radiation scatter to the resulting image and also helps reduce the radiation dose to the patient. To compensate magnification of the object to film distance, the distance between the cassette & the tube is increased to 180 cm. The standard exposure used is 105 kVp with some radiographers adjusting the mAs to -1 or -2. If manual settings are used then the average exposure setting is 90 kVp & 120 mAs. The horizontal ray is centered through the crease of groin to the middle of the cassette, midway between the anterior and posterior soft tissue of the thigh. A filter is used to optimise overall image density. One particularly important thing to note is that positioning for a horizontal lateral hip can be challenging as most patients are old & infirm and that they should be treated in a respectful & compassionate manner. For instance, the patient I x-rayed on Thursday was an elderly female who commented how 'undignified' she felt when her unaffected leg was raised onto the support. As such it's important to remember the patients’ dignity when undertaking this image, especially if the patient is of the opposite sex.

The resulting image (see below) should include upper 2/3rd of NOF with a clear view of acetabulm.
So there you have it, an overview of what the protocols are at my PBM hospital & what's involved.




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