Extrafascial out-of-plane continuous interscalene block using the C6 transverse process as a bony landmark -A case series.

backgroundBackground: Extrafascial interscalene block has been proposed to reduce phrenic nerve involvement while maintaining analgesic efficacy for shoulder surgery. However, a reproducible continuous catheter technique using a clear anatomical landmark has not been well described. CASE: We describe a case series of six patients undergoing shoulder surgery who received a continuous extrafascial interscalene block using the C6 transverse process as a bony landmark. Under ultrasound guidance, an 18-gauge Tuohy needle was advanced in a cranial-to-caudal out-of-plane trajectory toward the posterior tubercle of C6, and a catheter was placed within the middle scalene muscle. Continuous levobupivacaine infusion was maintained for 24 hours as part of multimodal analgesia.

conclusionsConclusions: This technique was associated with favorable postoperative analgesic profiles within a standardized multimodal regimen, without clinically apparent respiratory compromise. Given the absence of a control group, findings should be interpreted as hypothesis-generating. The C6 bony endpoint may improve reproducibility.