Figure 1: Duplex ultrasound image of the axillary artery, with the arm in a rested neutral position

Figure 2: Duplex

ultrasound image of the axillary artery, with the arm in

a hyperabducted position

DIAGNOSIS WITH ULTRASOUND Due to recent advancements in technology, ultrasound is now the preferred imaging choice for suspected vascular compression syndromes. When assessing for an upper- limb arterial compression syndrome, sonographers use the same arm manoeuvres, ie. costoclavicular manoeuvre and hyperabduction manoeuvre, as we have discussed already (6). With increasing numbers of physiotherapy departments and practices having access to diagnostic ultrasound machines for musculoskeletal assessment and biofeedback, the use of ultrasound to assess the vasculature and confirm diagnoses of suspected arterial compression syndromes has the potential to be a valuable tool for all physiotherapy clinics. It should be noted, however, that the success of using ultrasound for vascular assessment is operator-dependent and requires substantial training and practice. Figures 1 and 2 demonstrate the assessment of the third portion of the axillary artery with duplex ultrasound (combined B-mode and Doppler), with the arm in a neutral position (approximately 40o hyperabduction manoeuvre (120o extension, 90o

abduction, 30o

abduction) and in the horizontal

external rotation), respectively. The split-

screen facility allows simultaneous viewing of the artery in B-mode ultrasound and the spectral waveform. The latter allows an estimation of the blood-flow characteristics, such

as PSV, to be calculated. Figure 2 shows a doubling of the PSV compared with Fig. 1 (see the spectral waveform scale) as well as obvious changes in the artery diameter. It is speculated that these changes resulted from movement of the humeral head. Spencer and Reid (7) proposed a theoretical model that described an increase in PSV simultaneously with a reduction in vessel diameter. Their model predicts that diameter reductions have to be greater than 50% before PSV changes will occur. As a result, studies and clinical assessments use a doubling of PSV in the stress manoeuvre compared with the neutral arm position to identify a clinically significant arterial narrowing (this refers to cases where the measurement is obtained within the narrowed segment) (8). Where the measurement site is distal to the narrowed segment, a non-quantified dampened PSV with spectral broadening of the Doppler waveform indicates clinically significant compression (8). This classification is used as the standard clinical criteria for diagnosis of clinically significant arterial compression.

DIAGNOSTIC DILEMMAS Generally, therapists without access to advanced imaging equipment use a reduction of the radial pulse pressure or pulse disappearance (comparing the at-rest arm position with the diagnostic arm manoeuvre) as indicative of a positive

TABLE 1: DIAGNOSTIC ARM MANOEUVRES FOR UPPER LIMB ARTERIAL COMPRESSION SYNDROMES, THEIR COMPONENT PARTS AND THE ANATOMICAL SITES COMPRESSED

Deep Scapular Cervical Cervical

inspiration retraction extension rotation (towards

Adson’s 3 Modified Adson’s 3

Costoclavicular 3 AER

QSS EAST

QSS Hyperabduction 3 3

3 3 3

3 3 3

3 3

3 3 3 3

Cervical Abduction Glenohumeral Glenohumeral Exercise rotation

(away from affected side) affected side)

external rotation

horizontal extension

(hand gripping) compression

Site of arterial

ST, CC

ST, CC, RPM, HH, QSS

CC, (ST) CC, RPM, HH, 3 CC, RPM, HH, 3 CC, costoclavicular space; HH, humeral head; QSS, quadrilateral space syndrome; RPM, retro-pectoralis minor; ST, scalene triangle. 24 sportEX medicine 2009;40(Apr):23-26

ST, CC, RPM, HH, QSS