Ganglionic opioid analgesia is the name given to a therapeutic procedure used to treat chronic pain. It involves administering an opioid at a ganglion to interrupt the pain.
What is ganglionic opioid analgesia?
Ganglionic opioid analgesia (GLOA) is also known as ganglionic local opioid analgesia. When the method is used specifically to anesthetize the stellate ganglion, it is referred to as stellate blockade or stellate GLOA. Ganglia are nerve plexuses. They form an important switching point for the processing of information by the nerves. Thus, data from the organs or certain areas of the body are transmitted to the brain via the ganglia. This may involve the shoulder, arm or facial region, among others. Conversely, the brain passes on information to certain parts of the body. With the help of ganglionic opioid analgesia, it is possible to specifically interrupt pain signals by means of a nerve block. In a stellate blockade, for example, the cervical sympathetic nerve is temporarily switched off. For this purpose, the physician injects an analgesic from the opioid group. In this way, the pain improves after just a few minutes. Sometimes even complete freedom from pain is achieved, which lasts for several hours.
Function, effect and goals
For use, ganglionic opioid analgesia is used to treat pain. This primarily includes trigeminal neuralgia of the face, which is caused by the trigeminal nerve. However, pain in the head and neck can also be treated effectively with this procedure. Another indication is trigger point infiltration, which is used to treat myofascial pain syndromes. This refers to muscle pain caused by so-called trigger points within the muscle. The development of such trigger points includes overexertion or injury to the muscle as well as chronic poor posture. The muscles of the back, head and shoulder-arm area are particularly affected. Infiltrating these points with an analgesic leads to a temporary interruption of the sensation of pain. Other indications for ganglionic opioid analgesia include CRPS (Sudeck’s disease), shingles (herpes zoster) of the head or neck, migraine, spasm of blood vessels, root irritation syndromes of the cervical spine, and phantom limb pain following amputation. Blocking nerves with an opioid may also be done for diagnostic purposes to determine the cause of pain. Ganglionic opioid analgesia can also be used to prepare for physical therapy when there is pronounced pain during hand or arm movements. In GLOA therapy, the physician injects the patient with an opioid into the area of a ganglion to interrupt pain attacks or chronic pain. In most cases, the physician resorts to buprenorphine, which is a derivative of thebaine, a plant alkaloid. Special cannulas equipped with guiding instruments are used for this purpose. It is also possible to administer the opioid together with a local anesthetic. Depending on the condition to be treated, the analgesic is injected into the stellate ganglion, the Gasseri ganglion or the supercervical ganglion. The injected analgesic allows the pain to be eliminated for a few hours. It also dilates blood vessels and decreases sweat secretion. One of the most common uses of ganglionic opioid analgesia is to block the stellate ganglion. In this case, the opioid is injected into the anterior region of the neck next to the ganglion. Usually, no major pain is felt from the injection. Warming of the face, shoulder or arm may occur on the affected side. Sometimes the nasal mucosa or eyelid swells, but this indicates that the puncture was made in the right place. In addition, it is possible to check the effect by ultrasound or X-ray examination. It usually takes about 15 minutes for the analgesic to take effect. However, one disadvantage of ganglionic opioid analgesia is the time-limited duration of its effect. Therefore, other treatment methods usually need to be performed. A stellate GLOA is prepared by an X-ray examination of the spine.Around five days before the procedure, the patient must stop taking medication with a blood-thinning effect, which can be checked with a blood test. Six hours before ganglionic opioid analgesia, the patient must also not eat or smoke. After outpatient treatment, he or she should also refrain from operating vehicles and machines. The use of other medications should be discussed with the physician.
Risks, side effects, and hazards
Ganglionic opioid analgesia should not be performed if the patient has blood clotting disorders, an excitation conduction disorder of the heart associated with a slowed heartbeat, or ventilation disorders of the lungs. Various complications are also within the realm of possibility due to GLOA. For example, there is a risk of secondary bleeding and bruising at the injection site. Furthermore, the occurrence of irritation, dead tissue or abscesses cannot be ruled out. If a nerve is damaged during treatment, there is a risk of sensory disturbances or even paralysis. If the injection with the analgesic is inadvertently administered into an artery, this can result in an intensification of the opioid effect. Only rarely does the analgesic cross over to the spinal cord. In some cases, patients suffer allergic reactions. In addition, adverse side effects caused by the opioid include itching of the skin, urinary retention, fatigue, and constipation. Serious complications include cerebral seizures, plexus blockage, vertebral bruising, and esophageal perforation.
