Treating Back Pain Lumbar
Pain is the most complex problem modern medicine faces today and is the primary complaint prompting medical consultation. Compartmentalization of pain problems into physiological, physical, and psychosocial categories may be useful diagnostically, but must be synergistically joined to achieve therapeutic success. The interventional physiatrist (often the physical medicine and rehabilitation musculoskeletal and spine specialist) is a valuable and often most crucial member of the pain management team. Injury and tissue-specific therapeutic exercise programs must form the basis of physical rehabilitation and functional restoration protocols. The program can combine a core of sedentary exercises coupled with injury-specific exercises. Importantly, the protocol must expand to encompass psychotherapeutic intervention in chronic pain conditions. Neuromuscular reconditioning must be included to ensure a function-specific, task-oriented program. Essentially and most importantly, the program must be geared to enhance and foster functional recovery in the affected patient.
Diagnostic Discographic Injections
Lumbar discography remains a controversial diagnostic technique.1-12 To appreciate the historical controversy surrounding discography is to understand that its inception was a tenuous one, tainted by admonitions, suppositions, and contradictions. Proponents believe discography uniquely shows internal disc anatomy and identifies clinically symptomatic, or painful discs.7,10,13-15 In 1934, Mixter and Barr first called attention to the pathoanatomy of the herniated lumbar disc and its relationship to radicular dysfunction from neural compression.16 A neurogenic cause of discogenic pain independent of a neurocompressive paradigm was established in 1940 when Roofe revealed the innervation of the annulus fibrosus.17 Subsequently, four years later Knut Lindblom demonstrated the presence of radial annular fissures by injecting cadaveric discs.18 Vanharanta applied this basic scientific knowledge to demonstrate and explain pain provocation in mid to outer annular fissures.19 In 1952, Pierre Erlacher established the correlation of the nucleogram to nuclear anatomy by investigating cadaveric discs using contrast material and histological stains.20 Indications and the technique for lumbar discography was described in 1952 by Cloward and Busaid.21 Wiley studied 2,517 discal injections and reported a concrete and viable role for discography in the diagnostic evaluation of patients with axial pain and no definite disc prolapse on myelography.22 Since the initial procedure was performed, improved technique, technological advances, and a better understanding of pain have provided much needed refinement of discography as a potentially valuable diagnostic test.
The presence of degenerative disc changes does not necessarily correlate with clinical symptoms or a painful disc. Provocative testing for concordant pain is the most important aspect of discography and provides information regarding the clinical significance of the disc abnormality.7,10,13-15 There is literature documentation to suggest that the presence of outer annular ruptures is the best predictor of a painful degenerative disc rather than the degree of disc deterioration.6,23,24 CT discography has been shown to have higher sensitivity and specificity than CT, myelography, and CT myelography for internal disc disruption (IDD, a chemically-mediated abnormality of the nucleus pulposus or annulus fibrosus without disc contour defects), herniated nucleus pulposus (HNP), recurrent disc herniation, and foraminal disc herniation.25-28 CT discography interpretation is highly reproducible for grading annular degeneration and disruption.29 The presence of a "high intensity zone" (HIZ) on magnetic resonance imaging (MRI) has been shown to correlate 100 percent with an outer annular rupture by CT discography imaging, although 54 percent of discs with annular ruptures did not show a HIZ on MRI.29 The sensitivity and specificity of an HIZ in identifying discs that exactly reproduce discographic pain was 82 and 89 percent, respectively. Although MRI with gadolinium may be more accurate than CT discography in distinguishing recurrent disc herniations from postoperative scar tissue; CT discography is more sensitive than myelography, CT, or CT myelography.30,31 At the present time, MRI does not appear to be as sensitive or specific as CT discography in determining whether or not a disc is symptomatic.7,8,12 Discography and CT discography have been abnormal despite normal MRI scans, and they have shown asymptomatic discs in the presence of significantly abnormal MRI studies.6,7,12,13 Therefore, although MRI can reliably detect disc degeneration and in certain cases predict painful annular ruptures, many believe that only provocative discography can consistently determine the presence or absence of symptomatic annular ruptures.6,7,10,13,14
Lumbar discography uniquely tests for concordant pain reproduction in addition to investigating the internal disc structural integrity. In cases of IDD and indeterminate nuclear changes on MRI, discography can be beneficial.7,8 The major indications for lumbar discography include: 1) surgical planning of a lumbar fusion, 2) identifying the presence or absence of a painful disc among multiple degenerative discs, 3) testing the structural integrity of an adjacent disc to a known abnormality such as spondylolisthesis or fusion, and 4) evaluating a suspected lateral or recurrent disc herniation.6,25,30-35 In addition, discography is an integral part of intradiscal therapeutic procedures (e.g., intradiscal thermal annuloplasty, annular denervation, percutaneous laser microdiscectomy). According to the 1988 Position Statement on Discography by the Executive Committee of the North American Spine Society: "Discography is indicated in the evaluation of patients with unremitting spinal pain, with or without extremity pain, of greater than four months' duration, when the pain has been unresponsive to all appropriate methods of conservative therapy…"14 Although controversial, the concept of discogenic pain is described as a centralized, nonradicular pain produced during certain provocative activities. Patients can also have diffuse, nondermatomal lower limb pain that is associated with the lower back pain but not typically in isolation.36 Lumbar discography is believed to identify the presence or absence of symptomatic discs in patients with chronic low back pain. Therefore, proponents argue that the value of discography lies in its ability to provocatively test the discs for reproduction of discogenic back and leg pain.6,7,10,13,14,37