Lumbar Nerve Roots Injection

Nerve root inflammation

Causes and findings:
• Spinal stenosis
• Nerve-root entrapment
• Acute or chronic sciatica with or without root signs
• Painful: flexion and side bending usually away from painful side straight leg raise, slump test

Equipment:
Syringe - 1ml
Needle - 22G 3-3.5 inches (75-90mm) spinal
Kenalog 40 - 40 mg
Lidocaine - Nil
Total volume - 1 ml

Anatomy:
The lumbar nerve roots emerge obliquely from the vertebral canals between the transverse processes at the level of the spinous process. Draw a vertical line along the centre of the spinous processes and horizontal lines at each spinous level. Two fingers' width laterally along the horizontal line marks entry site for the needle.

Technique:
• Patient lies prone over small pillow to aid localization of spinous processes
• Identify spinous process at painful level and mark spot along horizontal line
• Insert needle and pass perpendicularly to depth of about 3 inches (7cm)
• Aspirate to ensure needle point is not intrathecal
• Inject solution as a bolus around nerve root

Aftercare:
Patient keeps mobile within pain limits and is reassessed up to 2 weeks later. Repeat as necessary.

Comments:
This injection can be especially effective when the patient is in severe pain and conservative manual therapy techniques are impossible to administer. It can also be given when caudal epidural has proved unsuccessful - the caudal is technically an easier procedure but the solution might not reach the affected part of the nerve root. The needle must be repositioned if it encounters bone at a distance of about 2 inches (5 cm) as this means it is touching the lamina or facet joint. Equally, repositioning is necessary if the patient complains of sharp 'electric shock' sensation because the needle will be in the nerve root. If clear fluid is aspirated the needle is intrathecal and the procedure must be abandoned, although it can be attempted a few days later. Two levels can be infiltrated at a time. A large patient may require a larger needle. If the first level injected does not relieve the symptoms, a level above or below can be tried. This is well worth trying before considering surgery.