CHAPTER 46 INTERVENTIONAL PAIN MANAGEMENT Charles E. Argoff, MD, Gary McCleane, MD 1. What is “interventional pain management”? Interventional pain management refers to a group of minor or major surgical procedures that can be used to control acute or chronic painful conditions. These include, but are not limited to, trigger point injections, different nerve blocks, intravenous infusions, radiofrequency lesioning, botulinum toxin injections, intraspinal analgesics, and spinal or deep brain stimulation techniques. Specific training is required to perform each of these types of procedures not only with respect to the procedure itself but also with respect to the management of potential complications of the intervention. Interventional pain management procedures are often an important component of a comprehensive pain treatment program. 2. What are trigger point injections? The management of myofascial pain is dependent on the elimination of painful myofascial trigger points. Trigger point injections involve the placement of a needle into the trigger point and the subsequent injection into the trigger point of a local anesthetic, a corticosteroid, or saline. Some clinicians have advocated the use of dry needling techniques in which nothing is injected, and the needle is moved around to deactivate the trigger point; however, although success with dry needling has been reported, it is clear that patients are initially more comfortable when local anesthetics are used during the injection. Various local anesthetics can be used, including 0.5% procaine, 1% lidocaine, or 0.25% bupivicaine. There is a very significant placebo effect and it is unclear whether or not the substance injected measurably alters the response. 3. Describe the potential benefits of trigger point injections It is hypothesized that the painful myofascial trigger point results from a chronic, perpetual, hyperexcitable state of both peripheral and central neurons, resulting in the painful neuromuscular syndrome. Myofascial trigger point injections can interrupt this pain cycle and lead to significant relief and improvement in function. Typically, multiple trigger points are injected during each treatment session. The duration of benefit of each set of injections is often measured in days; therefore, injections need to be offered as part of an interdisciplinary treatment program that includes therapeutic exercise, pharmacotherapy, and perhaps behavioral pain management approaches as well. 4. What is a nerve block? Nerve blocks are procedures that are designed to interfere with neural conduction to prevent or dampen pain. Afferent as well as efferent conduction may be interrupted. Local anesthetics are the most commonly injected substance. There is an impression that addition of a corticosteroid prolongs the duration of effect of the nerve block when used for the treatment of chronic, but not acute, pain problems. Diagnostic nerve blocks can define more clearly the anatomical etiology of the pain, to better understand whether or not there is a sympathetically maintained component and to help distinguish between peripheral and central pain syndromes. Prognostic nerve blocks are performed to help to predict response to a procedure that may have a greater duration of action than a nerve block with a local anesthetic. For example, a trigeminal nerve block may be performed with a local anesthetic as a predictor of what response could be experienced with a neurolytic agent such as glycerol. Prophylactic nerve blocks or preemptive analgesia are techniques employed to prevent the development of significant pain following surgery or trauma. Therapeutic nerve blocks may be used in either acute or chronic pain syndromes to reduce pain and encourage functional restoration when combined with a therapeutic exercise program. 5. What are some of the adverse effects of nerve blocks? Adverse effects of nerve blocks include allergic reactions to the local anesthetic used, effects related to toxic blood levels of the local anesthetic, physiologic manifestations of the procedure, unintended injury to neural or nonneural structures, and anxiety-related reactions. 6. When can nerve blocks be used for acute pain? Postoperative pain relief can be achieved for 12 or more hours with injection of long-acting local anesthetic into the soft tissues of operative sites following the excision of a breast mass or hernia repair, for example. Ilioinguinal nerve block can give postoperative pain relief after inguinal hernia repair. Acute bursitis and tendonitis can be treated with the infiltration of local anesthetic combined with an antiinflammatory drug such as methylprednisolone into the affected areas. Attempts to reduce the postoperative pain of various intraarticular surgeries by injecting into the joint cavity during the operation are now common. Bupivicaine and other local anesthetics are used in this regard. 7. What type of chronic pain syndromes can be treated with nerve blocks? Myofascial pain syndromes, painful scars, neuromas, degenerative joint syndrome, spinal degenerative conditions, chronic headache, and neuropathic pain syndromes may at some point in their course be treated with nerve blocks. Nerve blocks for chronic pain generally do not “cure” the problem, but rather begin a process that, when combined with other treatments, may result in a more manageable pain level and improved function. There are numerous examples of clinical conditions that can be treated with nerve blocks. Some of these nerve blocks are described in the following questions. 8. What is a paravertebral nerve block? Paravertebral nerve blocks are used diagnostically to determine the precise nerve roots or nerve segments responsible for the pain caused by a herniated disk, osteophytes, other spinal degenerative conditions, tumor, or vascular lesion. They are performed in the cervical, thoracic, lumbar, or sacral regions. They can be used prognostically for patients who are being considered for a neurostimulatory or neurolytic procedure and therapeutically to provide temporary relief of pain in the affected region. For example, frozen shoulders, rib fractures, postthoracotomy pain, and acute herpes zoster pain can be treated with this technique. Regardless of where the paravertebral block is performed, there is risk of unintended epidural or subarachnoid injection of the local anesthetic, which can result in respiratory depression and other adverse effects. In the thoracic region, pneumothorax is one of the more common complications. 9. What is an occipital nerve block? Occipital nerve blocks are performed to lessen the pain associated with a variety of chronic headache syndromes, including occipital neuralgia, cervicogenic headache, and chronic migraine. The greater occipital nerve can be blocked above the superior nuchal line approximately 3 cm lateral to the external occipital protuberance. Five milliliters of local anesthetic is injected. There are few complications, and the immediate results can be quite gratifying for the patient and the physician. This procedure can easily be performed in the office. 10. What is an intercostal nerve block? Only gold members can continue reading. 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CHAPTER 46 INTERVENTIONAL PAIN MANAGEMENT Charles E. Argoff, MD, Gary McCleane, MD 1. What is “interventional pain management”? Interventional pain management refers to a group of minor or major surgical procedures that can be used to control acute or chronic painful conditions. These include, but are not limited to, trigger point injections, different nerve blocks, intravenous infusions, radiofrequency lesioning, botulinum toxin injections, intraspinal analgesics, and spinal or deep brain stimulation techniques. Specific training is required to perform each of these types of procedures not only with respect to the procedure itself but also with respect to the management of potential complications of the intervention. Interventional pain management procedures are often an important component of a comprehensive pain treatment program. 2. What are trigger point injections? The management of myofascial pain is dependent on the elimination of painful myofascial trigger points. Trigger point injections involve the placement of a needle into the trigger point and the subsequent injection into the trigger point of a local anesthetic, a corticosteroid, or saline. Some clinicians have advocated the use of dry needling techniques in which nothing is injected, and the needle is moved around to deactivate the trigger point; however, although success with dry needling has been reported, it is clear that patients are initially more comfortable when local anesthetics are used during the injection. Various local anesthetics can be used, including 0.5% procaine, 1% lidocaine, or 0.25% bupivicaine. There is a very significant placebo effect and it is unclear whether or not the substance injected measurably alters the response. 3. Describe the potential benefits of trigger point injections It is hypothesized that the painful myofascial trigger point results from a chronic, perpetual, hyperexcitable state of both peripheral and central neurons, resulting in the painful neuromuscular syndrome. Myofascial trigger point injections can interrupt this pain cycle and lead to significant relief and improvement in function. Typically, multiple trigger points are injected during each treatment session. The duration of benefit of each set of injections is often measured in days; therefore, injections need to be offered as part of an interdisciplinary treatment program that includes therapeutic exercise, pharmacotherapy, and perhaps behavioral pain management approaches as well. 4. What is a nerve block? Nerve blocks are procedures that are designed to interfere with neural conduction to prevent or dampen pain. Afferent as well as efferent conduction may be interrupted. Local anesthetics are the most commonly injected substance. There is an impression that addition of a corticosteroid prolongs the duration of effect of the nerve block when used for the treatment of chronic, but not acute, pain problems. Diagnostic nerve blocks can define more clearly the anatomical etiology of the pain, to better understand whether or not there is a sympathetically maintained component and to help distinguish between peripheral and central pain syndromes. Prognostic nerve blocks are performed to help to predict response to a procedure that may have a greater duration of action than a nerve block with a local anesthetic. For example, a trigeminal nerve block may be performed with a local anesthetic as a predictor of what response could be experienced with a neurolytic agent such as glycerol. Prophylactic nerve blocks or preemptive analgesia are techniques employed to prevent the development of significant pain following surgery or trauma. Therapeutic nerve blocks may be used in either acute or chronic pain syndromes to reduce pain and encourage functional restoration when combined with a therapeutic exercise program. 5. What are some of the adverse effects of nerve blocks? Adverse effects of nerve blocks include allergic reactions to the local anesthetic used, effects related to toxic blood levels of the local anesthetic, physiologic manifestations of the procedure, unintended injury to neural or nonneural structures, and anxiety-related reactions. 6. When can nerve blocks be used for acute pain? Postoperative pain relief can be achieved for 12 or more hours with injection of long-acting local anesthetic into the soft tissues of operative sites following the excision of a breast mass or hernia repair, for example. Ilioinguinal nerve block can give postoperative pain relief after inguinal hernia repair. Acute bursitis and tendonitis can be treated with the infiltration of local anesthetic combined with an antiinflammatory drug such as methylprednisolone into the affected areas. Attempts to reduce the postoperative pain of various intraarticular surgeries by injecting into the joint cavity during the operation are now common. Bupivicaine and other local anesthetics are used in this regard. 7. What type of chronic pain syndromes can be treated with nerve blocks? Myofascial pain syndromes, painful scars, neuromas, degenerative joint syndrome, spinal degenerative conditions, chronic headache, and neuropathic pain syndromes may at some point in their course be treated with nerve blocks. Nerve blocks for chronic pain generally do not “cure” the problem, but rather begin a process that, when combined with other treatments, may result in a more manageable pain level and improved function. There are numerous examples of clinical conditions that can be treated with nerve blocks. Some of these nerve blocks are described in the following questions. 8. What is a paravertebral nerve block? Paravertebral nerve blocks are used diagnostically to determine the precise nerve roots or nerve segments responsible for the pain caused by a herniated disk, osteophytes, other spinal degenerative conditions, tumor, or vascular lesion. They are performed in the cervical, thoracic, lumbar, or sacral regions. They can be used prognostically for patients who are being considered for a neurostimulatory or neurolytic procedure and therapeutically to provide temporary relief of pain in the affected region. For example, frozen shoulders, rib fractures, postthoracotomy pain, and acute herpes zoster pain can be treated with this technique. Regardless of where the paravertebral block is performed, there is risk of unintended epidural or subarachnoid injection of the local anesthetic, which can result in respiratory depression and other adverse effects. In the thoracic region, pneumothorax is one of the more common complications. 9. What is an occipital nerve block? Occipital nerve blocks are performed to lessen the pain associated with a variety of chronic headache syndromes, including occipital neuralgia, cervicogenic headache, and chronic migraine. The greater occipital nerve can be blocked above the superior nuchal line approximately 3 cm lateral to the external occipital protuberance. Five milliliters of local anesthetic is injected. There are few complications, and the immediate results can be quite gratifying for the patient and the physician. This procedure can easily be performed in the office. 10. What is an intercostal nerve block? Only gold members can continue reading. Log In or Register to continue Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window) Related Related posts: Neuroimaging in the Patient with Pain Pharmacologic Management Postoperative Pain Management Sympathetic Neural Blockade Cancer Pain Syndromes Temporary Neural Blockade Stay updated, free articles. Join our Telegram channel Join Tags: Pain Management Secrets Jun 14, 2016 | Posted by admin in PAIN MEDICINE | Comments Off on Interventional Pain Management Full access? Get Clinical Tree
