The supraclavicular lateral paravascular approach for brachial plexus regional anesthesia: A simulation study using magnetic resonance imaging

In the supraclavicular lateral paravascular approach for brachial plexus re gional anesthesia by Moorthy et al. (Moorthy's block), the patient is supin e with the ipsilateral shoulder displaced anteriorly 5-8 cm. The needle dir ection is precisely defined in the coronal plane (using a Doppler flowprobe ) but not in the sagittal plane. We sought to determine whether the block c ould be simplified by keeping the shoulder in a neutral position, if the ne edle direction in the sagittal plane could be more precisely described, and if the risk of pneumothorax appeared acceptably small. These questions wer e studied by magnetic resonance imaging in 10 volunteers. Volume datasets o f the periclavicular region allowed precise positioning of simulated needle s. In all volunteers, Moorthy's block could be performed with the shoulder in a neutral position. The optimal needle trajectory passed 5 mm posterior to the clavicle and was 25 degrees posterior to the coronal plane, never ap proaching the pleura closer than 18 mm. We conclude that Moorthy's block ca n be performed with the shoulder in a neutral position, that more precise i nstructions for the needle direction can be given, and that the risk of pne umothorax seems minimal. This should be confirmed by a clinical study.