2.7 Anesthesia Delorosa
By Jesse McClure, MD, PhD, PharmD, and Julie G. Pilitsis, MD, PhD, MBA (both USA)
When I was asked to author this article on anesthesia dolorosa, my first thought was that I have seen far fewer people with this condition now than I did earlier in my career. My second thought was that I had a hard time thinking of one particular patient I had treated who had a “textbook” version of the condition. This is a bit unusual, because, after 25 years of practice, when I think of a diagnosis, in my mind’s eye, a patient’s face or name or computed tomography scan comes up.
Anesthesia dolorosa is a Latin term that describes nerve pain that comes after a trauma to the trigeminal nerve, usually within 6 months of a surgery or an injury. Most often, the trauma occurs after a surgery intended to treat trigeminal neuralgia (TN) such as MVD, balloon compression, radio-frequency ablation, or radiosurgery. The incidence after a single surgery has been reported to be 1:1000, but because anesthesia dolorosa is a rare disease, it is difficult to truly identify how common it is. It is, however, more common after multiple surgeries, each with the purpose of causing nerve injury. Sometimes, patients describe anesthesia dolorosa as the sensation of “bees stinging the entirety of my face,” and sometimes, they say it is “the feeling that goes along with a brain freeze,” a cold electric sensation. Others may say that it is a constant burning pain.
The problem with the term anesthesia dolorosa is that there is no ruler that can be used to identify when you have it. It is a condition relative to each individual with trigeminal nerve injury. So, really, it is a term that corresponds to a chronic sensation of what can be called a severe form of “dysesthesia,” meaning a burning, freezing, tingling, stinging discomfort.
For many years, anesthesia dolorosa has been considered a dreaded complication. Many patients have reported that the sensation was worse than the TN for which they were originally treated. These patient reports led surgeons to be more cautious and to restrict the amount of energy, pressure, or tension delivered to a nerve during surgery. During MVD surgery, nerve monitoring can improve safety. Furthermore, a better understanding of how anesthesia or the blood pressure control with anesthesia can affect nerves has led to more controlled outcomes. Thus, fortunately, anesthesia dolorosa is now less common after surgical procedures. More often now, cases are seen after facial trauma or surgical neurectomies (cutting of the nerve). Patients should be keenly aware of this complication if any surgeon proposes to cut a nerve as a form of treatment for facial pain, as this is a procedure with a high risk of causing anesthesia dolorosa.
When anesthesia dolorosa does occur, it should be treated as what is called a neuropathic pain condition. This means that further typical TN treatments such as MVD, glycerol rhizotomy, radiofrequency rhizotomy, balloon compression, and radiosurgery should be avoided. Neurectomy should never be done. Anything that could cause more damage to the nerve should be avoided. One reason physicians do not quickly move from one procedure to another in patients experiencing TN without allowing time for the procedure to work and for side effects to manifest is because of the potential for the development of this complication. Of course, there are times when immediate repeat surgery is necessary, such as when a postoperative MRI scan shows persistent or additional compression of the nerve or there are issues that limit the therapy from reaching the target during percutaneous procedures. However, in most cases, it is best to give 3 to 6 months between procedures, especially in cases where pain has improved but not to the degree the patient was hoping.
Anesthesia dolorosa remains difficult to treat. Fortunately, over time, symptoms may improve. What are other good treatments for neuropathic pain? They run the gamut and include means of treating the sensory, affective, and cognitive aspects of pain that occur in all chronic pain conditions for all patients, although the degree varies. It is unlikely that treating just the sensory component will resolve the pain adequately; treatment will often combine therapies. For the sensory component of pain, medications known to treat neuropathic pain, including gabapentin, pregabalin, anticonvulsants, antidepressants, and antispasmodics, are used. Historically, monoamine oxidase inhibitors and opioids were used in some cases, and they may occasionally still be used. Compounds including capsaicin and other pain creams may have benefits. Care needs to be taken when using such agents by the eye. There have been occasional reports of varying success with medications being administered directly to the painful area using catheters that are inserted within the spinal fluid space.
In general, the first surgical option is a procedure called high cervical spinal cord stimulation. It is designed to alter the firing of the tract to the trigeminal nerve that loops down in the spine just below the brain stem. The concept of its use is like that of a spinal cord stimulator for back or leg pain. A medical device that looks like a pacemaker to the heart can be used to create a type of white noise that is pain-relieving for the nerve. Device technology has advanced in the past decade. Many devices allow handheld or app-based management. Coupled with rechargeable implanted batteries, the devices are hardly visible and can be used for many years without the need for replacing batteries. In rare cases, stimulation to the brain through either the motor cortex or deep brain stimulation may be offered. Prior to considering surgery, a transcutaneous electrical nerve stimulation (TENS) unit may be used.
Western medicine does not typically have sufficient treatments for this condition, so an integrated approach may be needed. Noninflammatory diets, where foods that irritate the gut and body are avoided, are now being used. Auricular acupuncture, in which different regions of the body are reflected on areas of the ear, offers promise for some types of neuropathic facial pain. Additionally, vitamin or hormone deficiencies, which are not typically recognized, can worsen pain. A functional medicine evaluation may be helpful, although such evaluations are often not covered by insurance.
Living with chronic pain is taxing. It affects your physical and emotional well-being. It can impact your relationships both personally and professionally. It can leave you feeling completely helpless. It is important to recognize this and know that others with this condition feel the same. Mindfulness meditation can help to reduce chronic pain, and indeed, brain scans even look better afterwards. Yoga, tai chi, and biofeedback may aid in improving an individual’s reaction to and awareness of the pain. It is essential not to go through this alone. Having a community of peers to talk to who are experiencing chronic pain or other forms of facial pain can offer comfort. Remember, one size does not fit everyone regarding symptoms or treatments!
