Babeh Edi

The Swimmers Technique

Introduction

The swimmers projection of the cervico-thoracic junction is the bane of the trauma radiographer. The increasing use of CT scanning to assess the cervical spine in trauma patients has reduced (and in some cases eliminated) the reliance on the swimmers projection to demonstrate the cervico-thoracic junction. The swimmers technique has the worst of everything High dose High scatter Difficult positioning Doesn't work well on large patients or patients with shoulder injuries Often performed under pressure (e.g. in the resuscitation room) Important anatomy The swimmers technique is one of those signature projections for trauma radiographers- we all have our own techniques that we swear by. My experience is that all of the techniques work, and all of them don't work. I consider the true difficulty with this technique is that it is difficult to assess a patient and be sure which technique will work- at times apparently defying all logic. When searching for the ultimate 100% reliable technique, you will think that you have found it, and then it will let you down. One glimmer of hope is that CT scanning has become an increasingly popular technique for imaging cervical spine trauma. I have an increasingly low threshold for approaching the referring doctor to consider CT scanning of the cervico-thoracic junction if I consider that the swimmers projection is unlikely to be successful. One disadvantage of using CT to clear a trauma spine is that it entails a higher radiation dose to the patient. This page considers a variety of swimmers and swimmers-like techniques in no particular order.

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The swimmers technique is named after the swimming stroke referred to as freestyle, front crawl, or Australian Crawl.

Technique 1- Arms Forward

The swimmers view is all about getting the humeral heads projected clear of the cervical spine anatomy. It is usually the humeral heads that obscure the cervico-thoracic junction. This technique involves moves both humeral heads anteriorly. This can be achieved by having the patient cross their arms in front of them or by holding onto a bar attached to the upright bucky. This technique is typically successful on patients who have flexibility in their shoulders. Having said that, it is difficult to be sure if this technique will be successful just by looking at a patient. The example above is a case in point- this is a swimmers view image on a broad shouldered man. Note that one of the humeral heads is overlying the spine. In some patients both humeral heads can be moved clear of the spine. This image was taken using film/screen technology. A breathing technique has been employed to blur lung markings. A round cone has been utilized to reduce scatter radiation.

Technique 2- Arm-up, Arm-down

This version of the swimmers technique achieves an unobscured lateral view of the cervico-thoracic junction by positioning one arm up and one arm down. In terms of demonstrating the anatomy, it doesn't matter which arm is raised and which is pulled down. Some radiographers try to raise the right arm (when the patient is in the left lateral position) to reduce the radiation dose to the patient's thyroid. A sponge under one shoulder can help to separate the humeral heads. One of the flaws of this technique is that you tend to laterally flex the patient. This causes a loss of visualisation of the joint spaces.

Technique 3- The Arm Pull

This technique is sometimes utilised when you have come tantalisingly close to demonstrating the anatomy of interest, but not quite met the criteria. The idea is that if you can just move the shoulders inferiorly a little more, you will achieve a clear view of the vertebra that is obscured by the humeral head(s). The case above successfully uses this technique. This may, in reality, be much the same as the first technique given that the shoulders tend to roll forwards when pulled down. Caution: It is not considered acceptable practise in many institutions to arm-pull in patients with cervical trauma. This is now the case in my institution. A "ski rope" technique can be used in which the patient pulls their own arms down.

Technique 4- The Supine Lateral

This technique can be used in patients who do not have an acute injury and can lie on their sides. The position is very similar to a lateral thoracic spine position, except that the arm that is up (away from the table) is rolled posteriorly. One benefit of this position is that you can also include the whole of the thoracic spine in a single exposure. Breathing technique can be used to great advantage The patient often ends up slightly off lateral. I doubt that you are likely to miss a finding because the patient is a few degrees off true lateral. The disadvantage of producing an off-lateral position must be weighed against the advantages of this technique.

Issues

1. Collimation Radiologists have suggested the need to visualise C1 or C2 on the swimmers image so that they can count down and positively establish which levels have been imaged. The difficulty I have with this suggestion is that the image will be degraded by scatter radiation if the cones are opened to include the entire cervical spine. Of course, patient dose will also increase. It is not difficult to establish whether the area of interest is covered by considering the position of the first rib (although, this is not easy sometimes). If the area of interest is included, and it appears normal, it becomes an academic exercise to establish exactly which normal vertebra are covered (assuming you are sure that the anatomy of interest is imaged). Furthermore, in the majority of cases, there are characteristics of individual vertebral bodies that enable positive level identification on the swimmers image. For example, if C6 has a large anterior osteophyte, you will be able to establish which vertebra is C6 on the swimmers image. If there is an abnormality, the patient will likely proceed to CT for further imaging. A round cone is useful in reducing scatter radiation and can be used to standardise coning.

Case 1

This 47 year old patient presented to the Emergency Department in an ambulance after being involved in a MVA. The patient was experiencing neck pain and was referred for a trauma series which included cervical spine imaging. The lateral cervical spine image was achieved with passive lowering of the shoulders. The image did not adequately demonstrate the cervico-thoracic junction. There is artifact from the cervical immobolisation collar.

The radiographer noted that the patient's asthenic body habitus might be well suited to a 'both arms forward' lateral cervico-thoracic junction technique. The patient was asked to reach up with both hands and hold onto the wall bucky arm support shown in the photo below (arrowed) http://farm4.static.flickr.com/3595/3616473980_4d6a80401a.jpg

Both humeral heads were projected clear of the cervical/thoracic vertebrae resulting in good demonstration of the cervico-thoracic region. Note that despite the use of DR imaging technology, there is overexposure of the cervical region resulting in partial over-saturation of the image. (bra hardware noted)

Case 2

This 22 year old patient presented to the Emergency Department following a RTA/MVA. She was examined and referred for cervical spine radiography. The radiographer noticed that when the patient was asked to lower her shoulders the patient rolled her shoulders forward considerably. The ability of the patient to roll her shoulders forward was exploited to achieve demonstration of the upper thoracic vertebra. It is not unusual for patients, particularly younger female patients, to achieve this position.

Discussion

It is now widely considered best practice to never pull on a patient's arm(s) who has sustained a cervical spine injury. The swimmers view will test any trauma radiographer. If anyone has developed a technique that works every time, please post it on this wiki.

M.J.Fuller	Latest page update: made by M.J.Fuller , Feb 28 2011, 9:38 PM EST (about this update - complete history)