Carta Acesso aberto Revisado por pares

Correct nomenclature of superficial cervical plexus blocks

2004; Elsevier BV; Volume: 92; Issue: 5 Linguagem: Inglês

10.1093/bja/aeh550

ISSN

1471-6771

Autores

R. Telford, Mark D. Stoneham,

Tópico(s)

Medicine and Dermatology Studies History

Resumo

Editor'We read with interest the anatomical study by Pandit and colleagues1Pandit JJ Dutta D Morris JF Spread of injectate with superficial cervical plexus block in humans: an anatomical study.Br J Anaesth. 2003; 91: 733-735Abstract Full Text Full Text PDF PubMed Scopus (91) Google Scholar looking at the spread of injectate with superficial cervical plexus block in human cadavers. We feel that the term ‘superficial cervical plexus block’ as used to describe the site of injection in this cadaveric study is misleading as the paper clearly states that in four cadavers the injections of dye were made ‘just below the investing fascia’. This is not a ‘superficial cervical plexus block’. The classical technique of superficial cervical plexus block was described by Murphy,2Murphy TM Somatic blockade of head and neck.in: Cousins MJ Bridenbaugh PO Neural Blockade in Clinical Anaesthesia and Management of Pain. Lippincott Company, Philadelphia1988: 533-558Google Scholar and Scott.3Scott DB Cervical plexus block.in: Scott DB Techniques of Regional Anaesthesia. Appleton & Lange, Norwalk1989: 74-77Google Scholar Both these texts describe subcutaneous (superficial) injection of local anaesthetic. Not surprisingly, in the only cadaver in which the dye was injected subcutaneously in Pandit's study, none spread to the deeper tissues of the neck. The technique as described by Pandit and colleagues1Pandit JJ Dutta D Morris JF Spread of injectate with superficial cervical plexus block in humans: an anatomical study.Br J Anaesth. 2003; 91: 733-735Abstract Full Text Full Text PDF PubMed Scopus (91) Google Scholar might more correctly be termed an ‘intermediate’ cervical plexus block. This could be viewed as a third method of anaesthetizing the nerves of the cervical plexus, in addition to classical superficial and deep cervical plexus blocks. It is important to emphasize that classical superficial plexus block as described by Murphy2Murphy TM Somatic blockade of head and neck.in: Cousins MJ Bridenbaugh PO Neural Blockade in Clinical Anaesthesia and Management of Pain. Lippincott Company, Philadelphia1988: 533-558Google Scholar and Scott3Scott DB Cervical plexus block.in: Scott DB Techniques of Regional Anaesthesia. Appleton & Lange, Norwalk1989: 74-77Google Scholar is clinically effective for carotid endarterectomy. The main theoretical drawback of the use of superficial cervical plexus blocks alone is the lack of neuromuscular block of the neck. In practice, this does not seem to be a problem.4MD Stoneham, AR Doyle, JD Knighton, P DorjeJC. Stanley, Prospective randomized comparison of deep or superficial cervical plexus block for carotid endarterectomy surgery. Anesthesiology,; 89, 907–12Google Scholar We agree with the authors that a randomized controlled trial comparing ‘superficial’ and ‘intermediate’ cervical plexus blocks as the sole method for providing local anaesthesia for carotid endarterectomy is essential. As the majority of complications of cervical plexus block (intravascular injection, intrathecal injection and impaired diaphragmatic function) are associated with the deep block when local anaesthetic is placed around the roots of the cervical plexus, the ‘intermediate’ cervical plexus block could be a real step forward in the management of these difficult patients. Editor'We thank Drs Telford and Stoneham for their interest in our paper.1Pandit JJ Dutta D Morris JF Spread of injectate with superficial cervical plexus block in humans: an anatomical study.Br J Anaesth. 2003; 91: 733-735Abstract Full Text Full Text PDF PubMed Scopus (91) Google Scholar Existing literature indicates that there have been various methods described of the proper injection technique in superficial cervical plexus block. Murphy2Murphy TM Somatic blockade of head and neck.in: Cousins MJ Bridenbaugh PO Neural Blockade in Clinical Anaesthesia and Management of Pain. Lippincott Company, Philadelphia1988: 533-558Google Scholar, Scott3Scott DB Cervical plexus block.in: Scott DB Techniques of Regional Anaesthesia. Appleton & Lange, Norwalk1989: 74-77Google Scholar, Prys-Roberts,5Prys-Roberts C Brown BR Nunn JF International Practice of Anaesthesia. Butterworths, London1996Google Scholar and Katz6Katz J Atlas of Regional Anaesthesia. Appleton & Lange, Norwalk1994: 42Google Scholar have all described the superficial injection as being simply ‘subcutaneous’. However, Chaikof and colleagues have suggested it should be ‘intradermal’ (i.e. even more superficial).7Chaikof EL Dodson TF Thomas BL Smith RB Four steps to local anesthesia for endarterectomy of the carotid artery.Surg Gynecol Obstet. 1993; 177: 308-310PubMed Google Scholar In contrast, Yerzingatsian advised that the injection should properly be made into the body of the sternomastoid muscle, so that the solution is deposited below the investing fascia.8Yerzingatsian KL Thyroidectomy under local analgesia: the anatomical basis of cervical blocks.Ann Roy Coll Surg Engl. 1989; 71: 207-210PubMed Google Scholar It would perhaps take a medical historian to establish the proper chronology of these various suggestions for cervical plexus block to confirm which of them is the original or ‘classical’ method. The suggestion of Telford and Stoneham regarding nomenclature is therefore most welcome. The subcutaneous injection might indeed be termed ‘superficial’ (or simply ‘subcutaneous’), and the subinvesting fascia injection might be termed ‘intermediate’. As all complications associated with cervical plexus block arise from use of the deep injection,9Pandit JJ Satya-Krishna R McQuay H A comparison of the complication rate associated with superficial versus deep (or combined) block for carotid endarterectomy.Anesth Analg. 2003; 96: S279Google Scholar we are pleased that they agree with our suggestion that it is important for the (two safer) subcutaneous and intermediate injections to be compared directly in a randomized study.

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