Treatment       Nerve Root Blocks      
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Selective Transforaminal Nerve Root Blocks are useful in the pain relief clinic when an Epidural Injection has failed to help for sciatica due to nerve root irritation. They can be performed at the lumbar and cervical levels. Indications for a block include:-

  • The injection is performed under local anaesthesia, intravenous sedation , with X-ray screening, whilst lying face down.
  • A small diameter 3.5" needle is positioned in the Foramen , or nerve root exit hole, at the side of the spine. X-ray contrast medium is injected to outline the nerve root:-
    • Lumbar Radiculogram
    • Cervical Radiculogram
  • Once the needle is in the correct position, and not in the cerebrospinal fluid (CSF), a mixture containing 2% lignocaine and triamcinolone 20 mg is injected around the nerve root.
  • Commonly used steroids include:-
    • Triamcinolone (Kenalog )
    • Methylprednisolone (Depo-medrone )
  • - Information Leaflet.
  • Vital signs monitoring is usual for a short time after the procedure.
  • Arm or leg weakness, numbness, and temporary loss of use in the limb can occur in some patients, therefore an overnight stay at BMI The Meriden Hospital is advisable.
  • Technical failure - Inability to insert the needle into the nerve root foramen. This may be due to :-
    • Obesity causing poor X-ray pictures.
    • Difficulty steering the needle.
    • Severe degrees of Spondylolisthesis in the lumbar spine.
  • Failure to relieve the sciatic pain
  • Total Spinal Injection
    • This may occur if the spinal needle enters the CSF in the dural cuff around the nerve root. The use of X-ray contrast should reduce the risk of this happening.
  • Nerve injury caused by direct needle trauma.
  • Worse pain in a very small minority of cases, cause unknown.
Pulsed Radiofrequency
  • Indications - Should 1 or 2 nerve root blocks help the sciatica in the short term, but the pain returns after a few weeks or months, it would be sensible to consider Pulsed Radiofrequency Denervation in an attempt to make the pain relief last longer.
  • Technique - Treatment involves placing a needle in the same position as above. Once in position, a radiofrequency generator passes a high frequency current through the needle, gently heating up the dorsal root ganglion of the affected nerve root to a temperature of 42 degrees centigrade for between 4 and 8 minutes.
  • This temperature is not sufficiently high enough to damage the nerve, but can help to prevent it from transmitting painful signals from the peripheral nervous system to the brain, producing the effect of pain relief.
  • If successful, this procedure can be repeated on 2 - 3 occasions.
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