RT Journal Article SR Electronic T1 Novel cervical erector spinae plane block: interfascial layers remain important in the spread of anesthetics JF Regional Anesthesia & Pain Medicine JO Reg Anesth Pain Med FD BMJ Publishing Group Ltd SP rapm-2020-101788 DO 10.1136/rapm-2020-101788 A1 Ban C H Tsui A1 Hesham Elsharkawy YR 2020 UL http://rapm.bmj.com/content/early/2020/07/05/rapm-2020-101788.abstract AB