Spine

While detailed assessments require imaging such as MRI, with many structures around the spine relatively superficial, ultrasound can be used to provide peri-radicular nerve root (NR) and facet joint (FJ) injections in the lumbar and cervical spine. In addition, the sacro-iliac joints (SIJ) can be visualised for treatments.

9.1 Cervical spine

Traditionally, cervical facet joints (CFJ) and nerve roots (CNR) have been injected under fluoroscopic or CT guidance. The advent of real-time ultrasound has enabled this to be done with efficiency, safety and without the need for exposing the patient to undue radiation. The other advantage of ultrasound is that vascular structures can be visualized using doppler flow.

Joints

CFJ can be identified at the posterior aspect of the neck and injections can be undertaken using ultrasound guidance. In situations of diagnostic uncertainty, LA alone can be used, but for longer therapeutic duration steroid can be added.

9.1.1 Cervical Facet Joints

Patient position:	For the cervical facet joints (CFJ), the patient can be positioned in a side-lying position with the neck slightly side flexed to the contralateral side ( Fig. 9.1.1A ). This opens up the side requiring treatment, particularly in patients with shorter necks. Alternatively, the patient can be in a sitting position with the neck in a neutral or slightly extended position ( Fig. 9.1.1B ).
Identifying the anatomy:	Placed on the lateral aspect of the neck with the transducer in a SAX view, the C7 vertebra can be identified with its single posterior process. The C7/T1 facet joint can be seen by moving the transducer posteriorly and as the lamina comes into view the joint can be identified ( Fig. 9.1.1C–E ). The C6 level is identified by moving transducer proximally. It has two lateral processes and the C6 CFJ can be found by moving the transducer posteriorly. Higher levels can be identified in a similar manner.
Injections performed:	CSI for CFJ pain.
Recommended transducer:	Linear 8–12 mHz.
Equipment suggested:	Equipment preparation: Set 6 for facet, nerve root and sacro-iliac joint injections. Needle: 1.5- to 2.0-inch 23- or 25-gauge needle. Syringes: 3 mL for CSI. Medication: 2 mg dexamethasone (0.5 mL) and 1% lidocaine (1.5 mL) for standard CSI.
Injection technique:	Viewing the CFJ in the SAX, the needle can be introduced from a posterior position using an IP technique. The angle depends on body habitus but will be generally around 30–45 degrees ( Fig. 9.1.1F–H ). The needle tip can be brought to rest over the joint itself, with the bevel facing down, and once no blood flow is confirmed, the solution can be injected. The solution might not be seen flowing into the joint itself, but if delivered as close to is as possible, the active components will still have a therapeutic effect.

Nerves

The cervical nerve roots (CNR) can be visualised and injected under ultrasound guidance with a high degree of reliability and safety.

9.1.2 Cervical Nerve Roots (Peri-radicular)

Patient position:	For the cervical nerve roots (CNR), the patient can be placed in a side-lying position with the neck side flexed to the contralateral side ( Fig. 9.1.2A ). This opens the side requiring treatment and is particularly useful in patients with shorter necks. Alternatively, the patient can be in a sitting position with the neck neutral or slightly extended ( Fig. 9.1.2B ).
Identifying the anatomy:	Placed on the lateral aspect of the neck and the transducer in a SAX view ( Fig. 9.1.2C and D ), the C7 vertebra can be identified by the single, lateral process and the CNR can be seen exiting as the transducer is moved anteriorly ( Fig. 9.1.2E ). Similarly, the C6 CNR above this can be identified by locating the C6 level, which has an anterior and posterior process, and the nerve is situated between both processes ( Fig. 9.1.2F ). Levels above C6 will have an anterior and posterior process thereafter and the nerves will be seen between these. At levels above C7, it is important to apply the power doppler to identify where the vertebral artery is situated to avoid injury during the procedure.
Injections performed:	CSI for radicular pain (lidocaine is omitted).
Recommended transducer:	Linear 8–12 mHz.
Equipment suggested:	Equipment preparation: Set 6 for facet, nerve root and sacro-iliac joint injections. Needle: 1.5- to 2.0-inch 23- or 25-gauge needle. Syringes: 3 mL for CSI. Medication: 2 mg dexamethasone (0.5 mL) only.
Injection technique:	Viewing the CNR in the SAX, the needle can be introduced from a posterior position using an IP technique ( Fig. 9.1.2G and H ). The angle depends on body habitus but will be generally around 50–60 degrees ( Fig. 9.1.2I and J ). The needle tip can be brought to rest above and slightly posterior to the nerve with the bevel facing down. It is useful to have the power Doppler function active to ensure the vertebral blood vessel is not nearby prior to undertaking the procedure. If there is no flow, then the solution can be safely injected.