Nerves in the body pass through points of anatomic constriction, where they are bounded by rigid tissue. These often serve as sites of compression which may result in symptoms of tingling, numbness and muscle weakness. Alternatively, these nerves may also be compressed by cysts and other types of masses, or a nerve may not function properly due to trauma or inflammation. Injection of cortisone around the nerve sheath may suppress any inflammatory effect of the condition causing a patient’s symptoms. The most commonly injected nerve is the median nerve, which is classically compressed at the level of the carpal tunnel. This is commonly referred to as carpal tunnel syndrome.
Even though the injection may not result in bring about permanent pain relief, significant pain relief may be achieved for a prolonged period of time, potentially delaying surgery. Further to this, even though the relief obtained from an injection may be transient, it nevertheless is a worthwhile procedure, as a good response to a cortisone injection is a reliable predictor of which patients will likely respond to surgery.
Nerve blocks performed include:
- Stellate ganglion blocks
- Lumbar sympathetic plexus block/chemical sympathectomy
- Brachial and lumbar plexus blocks
- Median nerve blocks (Carpal tunnel syndrome)
- Lateral femoral cutaneous nerve block for meralgia paraesthetica
- Nerve entrapment syndromes
- Trigeminal neuralgia
- Occipital neuralgia (greater occipital nerve block)
- Post herpetic neuralgia
- Pudendal nerve block
Pudendal Nerve Block: In the images above, CT guided injection, following removal of needle demonstrates contrast around the pudendal nerve within the pudendal canal. This confirms needle placement and thus correct delivery of cortisone and local anaesthetic.
Pudendal nerve blocks are used to treat long standing severe pelvic, anorectal and genital pain, the latter known as vulvodynia in females. As most patients have had prolonged symptoms, a series of injections (usually three injections, two weeks apart) are required .
- Fanucci E, Manenti G, Ursone A, Fusco N, Mylonakou I, D'Urso S, Simonetti G. Role of interventional radiology in pudendal neuralgia: a description of techniques and review of the literature. Radiol Med 14(3):425-36, 2009