Anatomical variations detected during ultrasound-guided interscalene brachial plexus block and clinical implications

Year 2020, Volume: 33 Issue: 3, 141 - 145, 23.10.2020

Alper Kılıcaslan Funda Gok Ismail Hakkı Korucu Asiye Ozkan Resul Yılmaz

https://doi.org/10.5472/marumj.816311

Cited By: 1

Abstract

Objective: Our aim was to evaluate the anatomic variations detected during ultrasound-guided interscalene brachial plexus block
(US-ISB) and present their clinical implications.
Materials and Methods: After the ethical approval for the study was obtained from the local ethics committee, the files and US records
of patients who underwent US-ISB for anesthesia of the shoulder surgery were retrospectively analyzed.
Results: Anatomical variations which were considered to affect the block technique were detected in 13 (11.8%) of 110 patients. C5
cervical root pierced the anterior scalene muscle (ASM) in 4.5%, and ventral rami of C5 and/or C6 were located in ASM in 3.6% of
patients. There was a muscle bridge between C5 to C6 and C5 to C7 roots in 1.8% of the patients. The brachial plexus was located
medial to ASM and missing from interscalene groove in 1.8% of patients. In one case (C5 root was located in ASM), US-ISB resulted
in incomplete brachial plexus anesthesia, and so general anesthesia (GA) was performed.
Conclusion: Some of the brachial plexus variations in the interscalene area may be associated with further needle manipulation/
redirection and block failure. We consider that prospective studies including more populations are needed to elucidate the effects of
these variations on block parameters.

Keywords

Brachial plexus, Interscalene block, Ultrasonography, Variations

References

• Harry WG, Bennett JD, Guha SC. Scalene muscles and the brachial plexus: anatomical variations and their clinical significance. Clin Anat 1997;10:250-2. doi:10.1002/ (SICI)1098-2353(1997)10:4
• Cash CJ, Sardesai AM, Berman LH, et al. Spatial mapping of the brachial plexus using three-dimensional ultrasound. Br J Radiol 2005;78(936):1086-94. doi:10.1259/bjr/36348588
• Chin KJ, Niazi A, Chan V. Anomalous brachial plexus anatomy in the supraclavicular region detected by ultrasound. Anesth Analg 2008;107:729-31. doi: 10.1213/ane.0b013e31817dc887
• Gutton C, Choquet O, Antonini F, Grossi P. Ultrasoundguided interscalene block: influence of anatomic variations in clinical practice (French). Ann Fr Anesth Reanim 2010; 29: 770-5. doi: 10.1016/j.annfar.2010.07.013
• Kapral S, Greher M, Huber G, Willschke H, Kettner S, Kdolsky R, et al. Ultrasonographic guidance improves the success rate of interscalene brachial plexus blockade. Reg Anesth Pain Med 2008;33:253–8. doi: 10.1016/j.rapm.2007.10.011
• Kessler J, Gray AT. Sonography of scalene muscle anomalies for brachial plexus block. Reg Anesth Pain Med 2007;32:172- 3. doi: 10.1016/j.rapm.2006.09.011
• Feigl GC, Pixner T. Combination of variations of the interscalene gap as a pitfall for ultrasound-guided brachial plexus block. Reg Anesth Pain Med 2011;36:523–4. doi: 10.1097/AAP.0b013e31822897f1
• Abrahams MS, Panzer O, Atchabahian A, et al. Case Report: Limitation of Local Anesthetic Spread During Ultrasound- Guided Interscalene Block. Description of an Anatomic Variant With Clinical Correlation. Reg Anesth Pain Med 2008;33:357-9. doi:10.1016/j.rapm.2008.01.015
• Feigl GC, Litz RJ, Marhofer P. Anatomy of the brachial plexus and its implications for daily clinical practice: regional anesthesia is applied anatomy. Reg Anesth Pain Med.2020;45:620-7. doi: 10.1136/rapm-2020-101435
• Feigl GC, Pixner T. The cleidoatlanticus muscle: a potential pitfall for the practice of ultrasound guided interscalene brachial plexus block. Surg Radiol Anat 2011; 33: 823–5. doi: 10.1007/s00276.011.0820-z
• Kilicaslan A, Gürkan Y, Tekin M. A brachial plexus variation identified during ultrasound-guided interscalene block. Agri 2012; 24: 194. doi: 10.5505/agri.2012.34966
• Koscielniak-Nielsen ZJ. Ultrasound-guided peripheral nerve blocks: what are the benefits? Acta Anaesthesiol Scand 2008;52:727-37. doi: 10.1111/j.1399-6576.2008.01666.x
• Leonhard V, Smith, R, Caldwell, G, Smith, HF . Anatomical variations in the brachial plexus roots: implications for diagnosis of neurogenic thoracic outlet syndrome. Annals of Anatomy 2016;206: 21–6. doi.org/10.1016/j.aanat.2016.03.011
• Sakamoto Y. Spatial relationships between the morphologies and inner-vations of the scalene and anterior vertebral muscles. Ann Anat 2012 ;194:381-8. doi.org/10.1016/j. aanat.2011.11.004
• Yadav N, Saini N, Ayub A.Anatomical variations of interscalene brachial plexus block: Do they really matter? Saudi J Anaesth 2014;8:142-3. doi: 10.4103/1658-354X.125981
• VadeBoncouer TR, Weinberg GL, Oswald S, Angelov F. Early detection of intravascular injection during ultrasound-guided supraclavicular brachial plexus block. Reg Anesth Pain Med 2008;33:278–9. doi: 10.1016/j.rapm.2007.12.012