What is Pain Mapping?
Pain mapping is a diagnostic procedure in which controlled electrical stimulation is applied to specific spinal nerves, in order to reproduce a tingling sensation in the location of the patient‘s usual pain.
Why is Pain Mapping necessary?
There are times in which the source of the pain has not been clearly identified, or the treatment of a specific condition has not responded to conservative treatment or surgery. Since pain cannot be imaged (pain is a molecular level reaction in a nerve), modern technology such as MRI, CT Scan and other imaging frequently fail to identify the source of the pain.
How is Pain Mapping Done?
Pain mapping techniques are identical to diagnostic nerve root injections, with one major difference. Instead of a traditional needle, a specialized needle that contains a stimulating electrode is utilized. Once the needle is placed near the spinal nerve under live X-ray (fluoroscopy), a gentle electrical signal is sent to the nerve. When the patient feels a painless tingling sensation in the arm, chest or leg, they are asked if that sensation is in the same location as their usual pain. If it correlates, is called concordant pain reproduction, and the pain source is accurately diagnosed.
At this time, a local anesthetic with a duration of 2-4 hours in injected around the nerve and the response is noted.
After the Procedure
You will go back to the post anesthesia care unit (if you received intravenous sedation), where you will be monitored for 30-60 minutes according to your response. Post procedure instructions will be given in a pre-printed form. The patients are instructed to complete a pain diary in order to confirm the diagnosis. A follow up appointment will be made for post procedure evaluation in approximately one week. Medications will be given post procedure to assist in managing any discomfort. The post procedure discomfort is usually minor and can be manage with ice packs and medications.