Commentary: The Quest for Alternatives to Opioids in Chronic Pain: The Role of The Interventional Pain Physician
In the early days of my now two-decade career, I was first exposed to the theory of using opioids, which are a term for addictive narcotic medications, to effect or side effect based on increasing doses. This thought process began in the patient suffering from cancer pain, but evolved to include all patients with chronic pain. Unfortunately, in many of those treated with this strategy, the outcome was poor, with many issues arising. These issues included tolerance (the drug not working as well), addiction (taking the medicine for reasons other than pain), diversion (selling the medication or giving it to others), and accidental overdose causing illness or death. In others, increasing the dose caused hyperalgesia, a term meaning increased pain despite taking more pain medication. These factors have led physicians to seek a better method to treat chronic pain that is not at the end of life, and to find ways to reduce or eliminate the need for opioids. This article will focus on some alternatives specific to using procedures to eliminate or reduce opioids.
COMMONLY USED PROCEDURES USED TO ELIMINATE OR REDUCE ADDICTIVE PAIN MEDICATIONS
Fluoroscopic Guided Interventional Nerve Blocks: When the examination or imaging identifies the cause of pain, the fellowship trained interventional pain doctor can use an x-ray device called a fluoroscope to guide a needle to the part of the spine or nerve causing the problem.
Radiofrequency Ablation of the Spine: When an injection is helpful and gives temporary relief, it is said to be a diagnostic block, which means it helps identify the cause of pain. When this occurs with injection of the spinal joints the doctor can use a computer to heat the nerve to the joint and create a “numb” joint for 6 to 18 months. This is caused ablation.
Pulsed Radiofrequency: In some patients the nerves that are outside of the spine are the problem. The amount of heat you can use on these nerves is limited because they can be damaged. In this setting using lower heat in bursts or pulses of energy is an option to reduce pain.
Spinal Cord Stimulation (SCS): SCS devices are extremely helpful in many patients where all else has failed. This is a “pacemaker” for the spine. The device consists of a wire in the spine hooked to a computer and battery that delivers energy to the spinal cord. These devices are placed by a minimally invasive method and have been shown to help those suffering from nerve pain after failed spine surgery, from diabetes, shingles, and injury to a nerve.
Dorsal Root Ganglion (DRG-SCS): The spine is a complicated structure. There is a “ball” of nerves that serve as a “grand central station” of the body at several levels. New inventions have made it possible to place a small stimulator on this segment of the spine and treat severe pain in the feet, back, groin and chest. This device is currently approved in Europe and Australia and is being studied in the United States.
High Frequency SCS: Many are familiar with the “dog whistle” which is used to call dogs. The frequency of the noise is out of the range of most humans, but dogs hear the whistle and come running. A similar concept can be used in the spine. A new therapy, often called HF10, allows patients to have a spinal pacemaker placed that they cannot feel, but still in the majority causes pain relief for severe back problems. This device is currently approved in Europe and Australia and is being studied in the United States.
Peripheral Nerve Stimulation (PNS): In some settings, the pain is caused by a nerve that can be difficult or impossible to stimulate using spinal cord devices. In this case the doctor can implant a PNS. These devices are placed near the offending nerve and used to reduce pain. Examples include stimulating the nerve in the back of the head to treat migraine or the nerve in the arm after an unsuccessful carpal tunnel surgery. This device is currently approved in the United States in very specific settings, but future studies are ongoing.
Intrathecal Infusions: A doctor can place a small tube in the spine and a pump under the skin to deliver medication directly to the spinal fluid. These pumps have been called “morphine” pumps in the past, but now the FDA has approved Ziconotide. This drug, originally made from snail venom, is not an opioid and is not addictive. It is often used to treat patients in severe pain in whom opioid elimination is warranted. Several prospective randomized studies support its use in complex pain patients.
The scientific evidence for good pain relief using opioids long term is mixed. A few studies show success, but an equal or greater number show the risk may not be worth the benefit. Minimally invasive procedures do not always work, but in responders these types of procedures often lead to increased function, decreased pain and the elimination or reduction of addictive drugs.
Prior to considering a course of long term opioid treatment the patient and physician should consider other interventions that may reduce the risks associated with drug therapy and may either eliminate or reduce the need for addictive medications.
Timothy R. Deer, MD, FIPP, DABPM
President and CEO, The Center for Pain Relief
Clinical Professor of Anesthesiology, West Virginia University