Ultrasound-Guided Cervical Spine Injections

Published on 27/02/2015 by admin

Filed under Anesthesiology

Last modified 27/02/2015

Print this page

rate 1 star rate 2 star rate 3 star rate 4 star rate 5 star
Your rating: none, Average: 0 (0 votes)

This article have been viewed 1793 times

Chapter 21 Ultrasound-Guided Cervical Spine Injections

Chapter Overview

Chapter Synopsis: In the past few years, there has been a tremendous growth in interest in US-guided cervical injections as ultrasound allows direct, real-time visualization of soft tissue structures (e.g., vessels, nerves). Thus, it is an attractive alternative in cervical spine and neck injections, where there are a multitude of vital soft tissue structures compacted in a small area. This chapter will review various applications of ultrasound in cervical spine injections. Techniques for third occipital nerve block, cervical medial branch nerve block, and cervical facet intraarticular injections are discussed in detail. Advantages as well as limitations of ultrasound relative to fluoroscopy are highlighted. US-guided stellate ganglion block and US-guided atlanto-axial joint injections are discussed in other chapters.

Ultrasonography provides good visualization of bony surfaces, which may make it useful in various superficial spine injections (e.g., medial branch block, facet intraarticular injections, and nerve root blocks).1 However, it is not as useful in neuraxial blocks because of the bony artifacts and the limited acoustic window.

Important Points:

Clinical Pearls:

Clinical Pitfalls:

Ultrasound-Guided Cervical Nerve Root Block

Anatomy

The cervical spinal nerve occupies the lower part of the foramen with the epiradicular veins in the upper part. The radicular arteries arising from the vertebral, ascending cervical, and deep cervical arteries lie in close approximation to the spinal nerve.3

Huntoon4 was able to show that the ascending and deep cervical arteries may contribute to the anterior spinal artery (not only the vertebral artery). More than 20% of the foramina dissected had either the ascending or deep cervical artery or a large branch within 2 mm of the needle path for a cervical transforaminal procedure. One third of these vessels were spinal branches that entered the foramen posteriorly, potentially forming a radicular or a segmental feeder vessel to the spinal cord, making it vulnerable to inadvertent injury even during correct needle placement. Variable anastomoses between the vertebral and cervical arteries were found; therefore it is possible to introduce steroid particles into the vertebral circulation via the cervical arteries.4

Limitations of the Current Technique

Currently, the guidelines for cervical transforaminal injection technique involve introducing the needle under fluoroscopic guidance into the posterior aspect of the intervertebral foramen just anterior to the superior articular process in the oblique view to minimize the risk of injury to the vertebral artery or the nerve root.3 Despite strict adherence to these guidelines, adverse outcomes have been reported.5,6 A potential shortcoming of these current guidelines is the presence of a critical feeder vessel to the anterior spinal artery in the posterior aspect of the intervertebral foramen that could be injured in the pathway of the needle.4 Ultrasonography may be more adventitious because it allows for visualization of soft tissues, nerves, and vessels, and facilitates real-time visualization of the injectate around the nerve.

Literature Review of Ultrasound-Guided Cervical Nerve Root Block

Galiano et al7 described the use of ultrasonography in cervical periradicular injections in cadavers. They used CT images for confirmation. However, they were not able to comment on the relevant blood vessels in the vicinity of the vertebral foramen, and this raised some concerns about the safety of performing the procedure with ultrasonography at that time.8 Now with the introduction of high-resolution ultrasound transducers and gaining more experience, we were able to visualize small critical arteries with ultrasonography.

Narouze et al9 reported a pilot study of 10 patients who received cervical nerve root injections using ultrasonography as the primary imaging tool with fluoroscopy as the control. In four patients, these authors were able to identify vessels at the anterior aspect of the foramen; two patients had critical vessels at the posterior aspect of the foramen, and in one patient, this artery continued medially into the foramen, forming a segmental feeder artery. In these two cases, such vessels could have been injured easily in the pathway of a correctly placed needle under fluoroscopy.

Sonoanatomy and Ultrasound-Guided Technique for Cervical Selective Nerve Root Block

Ultrasound examination is usually performed using a high-resolution linear array transducer in the lateral decubitus position. The transducer is applied transversely to the lateral aspect of the neck to obtain a short-axis view of the cervical spine (Fig. 21-1). The cervical transverse process can be easily identified with the anterior and posterior tubercles as hyperechoic structures “two-humped camel” sign, and the hypoechoic round to oval nerve root in between (Fig. 21-2).9

Buy Membership for Anesthesiology Category to continue reading. Learn more here