Facet Joint Injections

Back pain may have a number of clearly identifiable causes for which treatment protocols may differ widely. The assessment of patients presenting with back pain as a symptom involves predominantly clinical assessment and special investigations (x-rays, MRI scans, diagnostic blocks) aimed at identifying a treatable cause for the symptoms and then devising a short and long term treatment plan to control or resolve the pain.

Facet joint pain is typically that pain felt over the spine which may radiate to the paraspinal region. In the neck commonly pain is felt to radiate into the back of the head, shoulders or parascapular area. In the lumbar spine it may radiate into the buttocks, back of thighs or hips.

Typically pain worsens with extension or rotation and then is relieved by rest or forward flexion. Most commonly facet joints become painful due to degeneration ( eg. arthritis) but may also be the source of pain due to strain, whiplash injury and there may be very little change identified on x-ray.

A number of patients will not present with a classic picture and symptoms may be difficult to differentiate from pain from other pathological causes (spinal stenosis, disc prolapse, fractures.) Each of these other pathologies requires a different diagnostic approach and different treatment regime and often a diagnostic injection may then be used to identify the pain source.

Treatment of facet joint pain involves a predominantly conservative / non-operative approach based around physiotherapy to strengthen spinal musculature and core control as well as maintaining flexibility. Some patients are in too much discomfort to attempt physiotherapy and facet injections with steroid can allow them to control pain adequately to enter a rehab protocol.

In patients where pain is not controlled for long enough for them to benefit from physiotherapy, facet joint rhizolysis can provide greater a longer period of benefit in carefully selected patients as the sensory nerves that detect pain are cauterised. This can allow them to enter and benefit from a rehab regime.

In some patients with pure facet joint pain where the pain can be isolated to a small number of joints, fusion of these joints will relieve pain. This is only suitable for a small number of patients and will not typically be the first treatment option to consider.

Procedure

This will usually be performed under local anaesthetic in most patients but can also be performed under sedation or general anaesthetic if a patient feels they are unlikely to tolerate local anaesthetic alone. This is a day case procedure and will either be performed in the operating theatre or radiology suite.

After administering a local anaesthetic a small needle is placed into the facet joint and around the joint where the nerve supply originates from. Typically a long working local anaesthetic (Marcain) and a steroid (depomedrone) are used. The local anaesthetic will provide pain relief for approximately 8 hours and it is common for there to be an increase in pain the following day which may continue for a few days.

This is due to bruising and should not cause alarm as it will gradually settle. The anti-inflammatory effect of the steroid may only start having a significant effect in some people after a few weeks. As soon as a positive effect is felt, physiotherapy should commence as it is the physiotherapy that is likely to give a long term benefit and is the key to long term improvement.

Injections may be repeated if only a short a short lived benefit is felt and consideration can also be given to facet joint rhizolysis which can have a longer effect than facet joint injections in correctly selected patients.

Facet joint injections should be considered safe although there are some risks which may be considered. The risk of infection or damage to nerves or the spine is extremely rare and unlikely. It is normal to have an increase in pain for a few days after the procedure and not all patients will have a beneficial response to these injections of steroid.

Mr Orpen will ask you to recount the response to the injections in the first hour, 6 hours, 12 hours, 24 hours and 1 week and 2 weeks and will normally like to see you in clinic after 2 weeks.