To the Editor:—
We read with interest the recent report by Martinez et al. 1regarding a combined infraclavicular plexus blockade with suprascapular nerve block for humeral head surgery in a patient with severe respiratory failure. However, we have some concerns with regard to the following points: First, it is not clearly stated whether the authors performed an infraclavicular plexus block using the coracoid technique (originally described by Whiffler 2) or the vertical infraclavicular technique (described by Kilka et al. 3). In the case report section the authors wrote, “brachial plexus was performed using “the coracoid and infraclavicular technique.” However, figure 1B in the case report of Martinez et al. shows the territories usually blocked by the vertical infraclavicular brachial plexus block. One must be aware of the different extensions of sensory blockade produced by the coracoid technique, the vertical infraclavicular technique, and the modified approach of the Raj technique. 4Because the coracoid technique approaches the brachial plexus more distally than the vertical infraclavicular technique, the axillary and musculocutaneus nerves are often missed or are not adequately blocked with the former technique. Deleuze et al. 5described a successful sensory blockade of the axillary nerve by the coracoid technique in only about 22%. Gaertner et al. 6showed that a multiple injection technique, as compared to a single injection, improved the overall success rate of the coracoid technique from 40% up to more than 70%, without detailing the effect on the axillary nerve.
Martinez performed a suprascapular nerve block to avoid hemidiaphragmatic paresis secondary to interscalene brachial plexus block. In the current case, the possibility of an iatrogenic pneumothorax during this procedure must be mentioned. 7This theoretical disadvantage is also described for the vertical infraclavicular technique. 8In the current case, a pneumothorax could have been at least as deleterious as a phrenic nerve paresis. As shown by Borgeat et al. 9and Boezaart et al. , 10the decrease of hemidiaphragmatic excursion after interscalene brachial plexus block can be reduced when the block is performed through the interscalene catheter rather than with a single bolus. The catheter technique, either performed at the interscalene or at the infraclavicular level (where the modified approach of the Raj technique seems to be the optimal solution 11), would have also offered good surgical conditions and efficient postoperative analgesia without the danger of a pneumothorax or an insufficient block.