Risk Analysis of Needle Injury to the Long Thoracic Nerve during Ultrasound-Guided C7 Selective Nerve Root Block.

Seok Kang,Ha-Mok Jeong,Beom-Suk Kim,Joon-Shik Yoon

doi:10.3390/medicina57060635

Seok Kang, Ha-Mok Jeong + Show 2 more

Open Access

https://doi.org/10.3390/medicina57060635

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Abstract

Background and Objectives: Ultrasound (US)-guided cervical selective nerve root block (SNRB) is a widely used treatment for upper limb radicular pain. The long thoracic nerve (LTN) passes through the middle scalene muscle (MSM) at the C7 level. The needle trajectory of US-guided C7 SNRB pierces the MSM, therefore indicating a high probability of injury to the LTN. We aimed to identify the LTN and to investigate the risk of needle injury to the nerve during US-guided C7 SNRB. Materials and Methods: This retrospective observational study included 30 patients who underwent US-guided SNRB at the C7 level in a university hospital. We measured the maximal cross-sectional diameter (MCSD) of the LTN and cross-sectional area (CSA) of the C7 nerve root and assessed the injury risk of LTN during US-guided C7 SNRB by simulating the trajectory of the needle in the ultrasound image. Results: The LTN was detectable in all the cases, located inside and outside the MSM in 19 (63.3%) and 11 (36.7%) of cases, respectively. The LTN’s mean MCSD was 2.10 mm (SD 0.13), and the C7 root’s CSA was 10.78 mm2 (SD 1.05). The LTN location was within the simulated risk zone in 86.7% (26/30) of cases. Conclusion: Our findings suggest a high potential for LTN injury during US-guided C7 SNRB. The clear visualization of LTNs in the US images implies that US guidance may help avoid nerve damage and make the procedure safer. When performing US-guided C7 SNRB, physicians should take into consideration the location of the LTN.

Highlights

Our findings suggest a high potential for long thoracic nerve (LTN) injury during US-guided C7 selective nerve root block (SNRB)
Ultrasound (US)-guided cervical selective nerve root block (SNRB) is a safer alternative procedure because it can be performed while identifying dangerous structures, including blood vessels and peripheral nerves around the target nerve root [4,5,6,7,8]
Tracing the nerve roots from the C5 to C7 level, we identified the branches from the C5 and C6 nerve roots merging into the LTN around the middle scalene muscle (MSM)

Summary

Introduction

Cervical transforaminal steroid injection (TFSI) is an effective treatment for radiating pain in the upper limb caused by cervical disc disorders [1,2]. TFSI is usually conducted under fluoroscopy or computed tomography (CT) guidance. Such a procedure bears the risk of accidental intravascular injection and can cause fatal complications, such as brain stem and spinal cord infarctions [3]. Ultrasound (US)-guided cervical selective nerve root block (SNRB) is a safer alternative procedure because it can be performed while identifying dangerous structures, including blood vessels and peripheral nerves around the target nerve root [4,5,6,7,8]

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Conclusion