SPORTS MEDICINE

MUSCULOSKELETAL ULTRASOUND IN CLINICAL PRACTICE

Part Three: Ultrasound-guided interventions and biofeedback

INTRODUCTION The first two parts of this short series presented an overview of the equipment, training and general diagnostic repetroire of musculoskeletal ultrasound (mskus) as typically applied by non-consultant musculoskeletal and sports injury clinicians. In the final part we present a summary of ultrasound guided techniques and the novel use of ultrasound biofeedback in musculoskeletal rehabilitation.

By Dr Duncan Robertson and Dr James Brown

INTERVENTIONAL MSKUS MSKUS can be used to guide instruments – usually a needle – for aspiration, injection or possibly ‘needling’ of a tendon lesion (1- 4). The injection may be for the purpose of confirming the diagnosis (5) or for therapy such as accurate delivery of medication within a structure (6,7). Debate still persists about the exact role of needle guidance. Some still argue that there is no difference in injection accuracy (8), though the majority of studies show ultrasound guidance in shoulder injections (figures 1 and 2) improves accuracy by around 30% (9,10). Furthermore research has confirmed especially in the shoulder that accuracy of needle placement in the sub-acromial bursa affects outcomes (11).

Clinical governance is a growing issue relating to the risks and

FIGURE 1: TWO EXAMPLES OF US-GUIDED INJECTION TECHNIQUES FOR SUB-DELTOID BURSITIS/SUB-ACROMIAL IMPINGEMENT

In both cases, the patient is positioned for a longitudinal approach. Good practice means that the needle entry point should remain approximately 1cm away from the leading edge of the probe at all times, even if a probe sheath and jelly from a sterile sachet are used. Image A (top) suggests the advantage of reducing drag on the needle from the weight of the syringe. A further option is to actually tape the syringe and connecting tube to the adjacent skin – this

is especially helpful if extra final adjustment of the needle tip is needed, as this requires the use of both hands.

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outcomes associated with intervention. Ultrasound guidance minimises these risks ensuring the visualisation of the needle away from potentially important structures as well as demonstrat- ing accurate delivery of therapy. From our own personal experience, patients seem to appreciate the visual feedback in injection accuracy; irrespective of how well or poorly they respond to the treatment, they have the knowledge that (assuming the diagnosis was correct) the medication was put into the right spot. Even though the prevalence of injection-associated litigation is not that high, common sense suggests that ultrasound-guidance probably has a positive effect on reducing the risk of this.

Barbotage in calcific tendinopathy of the shoulder The rationale of barbotage is to decompress the supraspinatus tendon by repeated needling of the calcific deposit, followed by

FIGURE 2: ULTRASOUND–GUIDED INJECTION INTO THE SUB-DELTOID BURSA

On the left and right we see the final stage of an ultrasound- guided injection into the subdeltoid bursa. Note that the bursa can be seen to distend as injectate enters the bursa (white arrow). The scan prior to injection has given an accurate guide already to needle placement, and if done properly, there should only be small final ultrasound-guided adjustments to the needle. The visible movement of the injection material into the bursa is the final barometer of the success of the procedure.

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