Chapter 92. Interventional Management of Chronic Pain

The best pain medicine practitioners strike a reasonable balance between interventional and noninterventional management. This practice pattern is sustainable, and those adopting a balanced style of practice will be able to adapt to evolving scientific evidence that appears to support pain treatment, regardless of the type of treatment.

Although the evidence supporting the need for routine radiographic guidance is still evolving, the intuitive appeal of this more precise approach has evolved to the point where most practitioners now perform at least a portion of their injections using fluoroscopic guidance.

The key to safety and success of any interventional pain technique is a clear understanding of normal anatomy. The procedures described in this chapter require an understanding of the normal anatomy of the spine, including the epidural and subarachnoid spaces, zygapophyseal joints, intervertebral disks, and, most importantly, the spinal cord with its somatic and sympathetic components.

Epidural steroid injections are efficacious in the treatment of acute lumbosacral radicular pain or in radiculopathies secondary to herniated or bulging disks. Epidural steroid injections also have been used to treat back pain secondary to degenerative disk disease, spinal stenosis, trauma, spondylolysis or spondylolisthesis, and in pain following laminectomy. The epidural space can be approached through the interlaminar space (median or paramedian), intervertebral foramen (transforaminal), or sacral hiatus (caudal). The approach selected depends on patient selection, indication for injection, practitioner's experience, and availability of imaging. We are still lacking large-scale studies comparing clinical outcomes with the transforaminal versus the interlaminar approach.

Many practitioners continue to use sympathetic blockade as a part of a multidisciplinary approach to treating complex regional pain syndrome. Sympathetic blocks are one tool that can reduce pain and facilitate functional recovery.

Intra-articular facet injection has been largely supplanted by radiofrequency treatment techniques for facet-related pain. Clinical experience and a limited number of published observational studies suggest that intra-articular injection of local anesthetic and steroid leads to relief of facet-related pain that is of limited duration. In contrast, radiofrequency treatment is safe and effective in producing longer-term pain relief in the same group of patients.

Discography is a diagnostic test in which radiographic contrast is injected into the nucleus pulposus of the intervertebral disk. Although originally developed for the study of disk herniation, discography now is used most commonly to identify symptomatic disk degeneration. The usefulness of this diagnostic test remains controversial.

Intrathecal morphine and other opioids are now widely used as adjuncts in the treatment of acute and chronic pain, and a number of agents show promise as analgesic agents with spinal selectivity. Patient selection for intraspinal pain therapy is empiric and remains the subject of debate. In general, intrathecal drug delivery is reserved for patients with severe pain that does not respond to conservative treatment.

Direct electrical stimulation of the dorsal columns, known as spinal cord stimulation or dorsal column stimulation, has proven effective, particularly for treatment of chronic radicular pain. Patient selection for spinal cord stimulation is empiric and remains the subject of some debate. In general, ...