We read with interest both the description of the serratus plane block , and the accompanying editorial  in Anaesthesia. The discussion regarding pre-existing regional anaesthetic techniques appropriate for chest wall surgery included mention of interpleural blocks. Despite acknowledging the production of ‘reliable unilateral segmental thoracic analgesia’ , interpleural blocks were only briefly referred to and then largely dismissed owing to the lack of published data and a quoted 2% risk of pneumothorax. The pneumothorax risk quoted comes from the review by Dravid and Paul published in Anaesthesia in 2007 , in turn obtained from a separate retrospective literature review of 703 cases , among which a variety of techniques were used. In fact, Dravid and Paul acknowledged that “the true incidence of pneumothorax may never be known”.
We believe that our hospital has performed the world's largest series of interpleural blocks, more than 7000 performed since 1994. We use the ‘saline infusion technique’ to site interpleural blocks correctly [5, 6]. After the first few hundred patients, our radiology department declined to carry out chest X-rays for each patient because there had been a zero incidence of pneumothorax. Since then, there have been a total of three clinically detectable pneumothoraces (and none in recent years), all of which were attributable to inexperienced trainees' failing to adhere to the method described. None of these cases required treatment beyond supplemental oxygen. The technique is used for all chest wall surgery at our institution, including major breast reconstruction. Suggestions about carrying out randomised controlled trials have been rejected by the surgeons at our hospital because they are already convinced of the benefits from the existing technique. The use of postoperative opioids in these cases is almost non-existent.
It is our belief, therefore, that interpleural block is the ideal regional anaesthetic technique for chest wall surgery. We can only presume that (natural) anxiety about passing a 16-G needle through the parietal pleura has prevented more widespread adoption or studies of this technique.