Sciatica is the most common presentation of neuropathic pain. It is an inflammatory pain, caused by cytokines such as tumour necrosis factor (TNF) and interleukins 6 and 8, found in the nucleus pulposis as it leaks out on to the exiting nerve roots.
This inflammatory origin of pain is the rationale for an epidural steroid injection in the treatment of sciatica. Cortisone is a powerful anti-inflammatory agent and when injected directly onto the inflamed nerve root lead to a reduction in inflammation, swelling and ultimately pain relief.
The inflammatory nature of the nucleus pulposis is also the rationale for disc-decompression surgery. This intention is to surgically remove the extruded disc contents, eliminating the source of inflammation and subsequent swelling, ultimately leading to pain relief.
In many ways, surgery has been seen as the definitive treatment, leading to a long-term resolution of pain. Unfortunately, a successful surgical outcome is not necessarily permanent, as there is always the possibility of a recurrence of the prolapse at the same level, on the same or opposite side, or at a different level. Previous Cochrane meta-analyses have consistently shown that outcomes are similar after a prolapsed disc, after 2 years regardless of whether treatment was surgical, injections, medications or conservative.
This study by the National Institute for Health Research (NIHR) would appear to consolidate Cochrane findings. Ultimately there is no difference in pain outcomes in sciatica when treatment was with micro discectomy or with Transforaminal Epidural Steroid Injections. Injections were shown to be significantly more cost effective, so, with similar efficacy, this would seem like a sensible first choice treatment in the management of both acute and chronic sciatica