Sciatic Nerve Block Injections
The sciatic nerve is the largest, longest, and widest single nerve in the human body. It originates in the sacral plexus (bundle of nerves) of the lower spine and extends all the way down the back of the leg to the toes. The sciatic nerve primarily supplies the muscles of the lower leg. It also supplies sensation to the sole of the foot, ankle, the lower leg, and the back of the thigh. Damage to the sciatic nerve can result in numerous symptoms, including lower back pain, muscle weakness, and reflex abnormalities. The sciatic nerve can be damaged anywhere; however, lower leg complications are most common, and include the inability to bend the knee, an absence of ankle reflexes, or difficulty in rotating and bending the foot.
Treatment:
The nerve roots in your spine are covered by the dura. The sleeve like space that surrounds the dura is known as the epidural space. An epidural injection places anti-inflammatory medicine (i.e. cortisone) into the epidural space to reduce nerve inflammation, and hopefully reduce the severity of the symptoms. Although not always helpful, epidural injections reduce pain and improve symptoms in most people within 3-7 days. Even though epidural injections may not always be a permanent fix, allowing certain periods of time without pain can be of great benefit and may augment other techniques. Physical therapy may be more effective in concurrence with epidural injections since less pain means a superior therapy session.
Remember, injections are not the best treatment for all pain types. Even when they are appropriate, they are usually more effective as part of a more comprehensive treatment strategy.
Depending on the circumstances, complete destruction of the nerve (as opposed to temporary numbing through a local anesthetic) could be considered. This is referred to as a rhizotomy. Aside from the obvious complications of nerve destruction, permanently damaging a nerve may inadvertently and inevitably damage the soft tissue adjacent to that nerve as well.
sources:
http://www.spine-health.com/conditions/spine-anatomy/sciatic-nerve-anatomy
http://www.healthline.com/human-body-maps/sciatic-nerve
https://www.spineuniverse.com/conditions/sciatica