Sir,
We thank Bos et al.[1] for their interest in our case report 'Unilateral giant internal jugular vein impeding brachial plexus nerve block'. They had very astutely estimated the diameter of the internal jugular vein to be over 5 cm and it was indeed 6.2 cm. Unfortunately we do not have the image measuring this at present.
This measurement was not made at the level of the cricoid cartilage, and no Trendelenburg position or Valsalva manoeuvre was used. The head was however rotated by 45°. There was no visible or palpable mass to consider phlebectasia. It is unfortunate that we did not investigate for connective tissue disorders affecting vessels, however the condition was unilateral and no other signs of connective tissue disorder were apparent. Screening echocardiography performed in the operating room showed preserved cardiac anatomy and function. On interrogating the IVC with M-mode ultrasound while the patient was spontaneously breathing, the IVC maximum diameter was 1.5 cm at the hepatic vein entrance with a collapsibility index of 20% suggesting a hypovolemic or fluid responsive state.[2,3]
With regard to Figure 1 in our case report,[4] the image provided, shows the internal jugular vein, common carotid artery, and the brachial plexus. As Bos et al. have correctly stated this is not the supraclavicular location for a brachial plexus block. However, the same large internal jugular vein anatomy was continuing into the supraclavivular fossa impeding the line of approach to the brachial plexus. The image of the same is also unfortunately not available at this time.
Figure 1.
(a) Ultrasound image showing right supraclavicular brachial plexus (encircled) located below a giant hypoechoic ovoid structure, Internal jugular vein (IJV). (b) Colour doppler showing flow in the right IJV and adjoining veins. (c) M-mode ultrasonography through the hypoechoic right IJV. (d) The left IJV and common carotid artery (CCA) on the ultrasonography
The paper by Lin et al., as again rightly pointed out, does not give the incidence of unilateral giant internal jugular vein, but as a whole the incidence of unilateral anomalies. We could not find the frequency with which a unilateral giant internal jugular vein occurs during our literature search. We provided the Lin et al. reference to give the readers an idea as to what percentage of the anomalous internal jugular veins occur unilaterally. And hence it is a giant internal jugular vein which is much rarer.
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REFERENCES
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