The incidence of one having a lumbar herniated disc in the US is one percent, which makes it a very common phenomenon. If the disc herniation is obvious on imaging studies and correlates with the patient’s symptoms of radiculopathy and sciatica, the options for treatment are clear.
Physical therapy, epidural steroid injections, pain medication, spinal decompression therapy, chiropractic treatment, essentially anything non-operative and if after 6-8 weeks the pain persists the option for surgery is thrown into the mix.
What happens with sciatica symptoms that do not correlate with significant imaging study findings? For example, the person has symptoms in the right leg that are consistent with a Lumbar 5 radiculopahty, however, there is no compression obvious on the L5 right side when viewing the MRI.
Those are the times a Lumbar Selective Nerve Block may help. The pain management physician thinks sciatica is a result of pathology at the level of the nerve but desires to both 1) Confirm the suspicions and 2) Provide pain relief. So the Lumbar Selective Nerve Block exhibits a diagnostic purpose as well as a therapeutic purpose.
The technique for the spinal injection is to place numbing medicine plus or minus steroid just as one would perform a transforaminal epidural injection. The numbing medicine bathes the nerve root that is suspected of causing the symptoms and then the patient keeps a log of subsequent pain relief achieved. One wants the numbing medicine around the actual nerve root suspected, not just over the area before the nerve root breaks off from the dural sac. That area is too general and can provide confusing results.
Once the doctor sees the result, it can help going forward with treatment decisions such as physical therapy, pain management, spinal decompression, whether that treatment consists of further non-operative methods or spine surgical intervention.