By: Tarun Jolly, MD, Elizabeth Srejic
Discography is a diagnostic procedure used to determine whether back pain is being caused by a spinal disc. It used when clinical evaluation suggests a patient’s back or neck pain originates from an intervertebral disc, and other sources of pain have been ruled out[1].
The spinal disc has been implicated as an etiology (cause) of back pain based on clinical and other research. However, the exact role and mechanism of the disc in the development of back pain still remains undefined. At the current level of understanding, discography is regarded as the best tool to evaluate disc-related pain[2].
In brief, discography is a minimally invasive, relatively painless procedure in which a special dye is injected into a disc suspected of causing the patient’s pain. The dye spreads and creates a detailed image of the disc on a screen through the use of fluoroscopy, or real-time x-ray. The technology allows the doctor to scrutinize and evaluate the condition of the tested disc and recommend an appropriate course of treatment.
Understanding the anatomy and physiological function of the spine is of utmost importance in evaluating a person with back pain. The bony spine is positioned to allow individual vertebrae (bones of the spine) to provide a flexible support structure while also protecting the spinal cord.
In most people, the spine or vertebral column is comprised of 33 interlocking bones, or vertebrae, which are connected by fibrous bands called ligaments and divided into five regions: cervical, thoracic, lumbar, sacral and coccygeal. The vertebral column provides support for the upper body as well as protection for the spinal cord, and furnishes attachment points for the ribs and muscles of the back. Between the vertebrae are the elastic intervertebral discs, which cushion the bones of the spine and promote flexibility. Deterioration, disease, and deformity of these discs can lead to impaired movement as well as severe pain.
Located between neighboring vertebrae are pliable intervertebral discs filled with a soft, gelatinous material called the nucleus pulposus. This jellylike material is designed to manage compression by dispersing pressure. The nucleus pulposus consists of chondrocytes, collagen fibrils, and proteoglycan aggrecans containing hyaluronic long chains that attract water. As part of the aging process, the nucleus propulsus gradually loses its water content, which lowers its ability to absorb shock and promote smooth movement.
Discography allows the doctor to visualize a disc suspected of causing back pain. It can be a particularly valuable diagnostic tool when the doctor desires a detailed look at the morphology (structure) of a problematic disc.
Pain that originates from intervertebral discs is called discogenic pain. Disc pain is a common etiology of back pain; in fact, an estimated 40% of chronic lumbosacral back pain is attributed to spinal discs[3]. Disc disease may be acute, as in the case of damage arising from trauma, or chronic, as in a steady condition that produces pain for more than three months.
Two common disc problems that produce pain are bulging disc and herniated disc. Bulging disc occurs when excess pressure is put upon a disc, causing it to bulge out of place. Herniated disc occurs when a tear or softening in the outer fibrous layer (the annulus fibrosis) of an intervertebral disc forces the pliable inner material through the weakened part of the disc. Both bulging and herniated discs can become painful by irritating adjacent nerves and compressing the spinal cord.
Another reason for discogenic pain is Degenerative Disc Disease (DDD), or gradual deterioration of the intervertebral discs of the spine that occurs as part of the aging process. In DDD, a detrimental cascade of changes in cellular, biochemical, structural and functional properties of spinal discs often results in back pain[4]. Although DDD may occur anywhere in the spine, it commonly affects the low back and the neck.
Patients with DDD experience degenerative changes that lead to tears within the annulus fibrosis. Tears within the annulus stimulate the ingrowth of blood vessels and accompanying pain receptors (nociceptors) into the outer and occasionally inner disc, and sensitization of these nociceptors by various inflammatory processes may lead to chronic discogenic pain.
The thoracic spine extends from the round bump at the base of the neck (T1) all the way down to T12 (about 4 – 5 ” below the bra-strap).
The thoracic spine extends from the round bump at the base of the neck (T1) all the way down to T12 (about 4 – 5 ” below the bra-strap).
The thoracic spine extends from the round bump at the base of the neck (T1) all the way down to T12 (about 4 – 5 ” below the bra-strap).
When the doctor has ruled out causes of back pain that do not pertain to the intervertebral disc, such as osteoarthritis, which is a disease of the bone, a discographic study may be ordered to provide a detailed picture of the structure of a painful disc. Based upon the information provided by the study, the doctor will recommend a course of treatment.
Discography is typically performed when routine tests such as MRI have failed to reveal the etiology of a patient’s back or neck pain. Discography is also used to evaluate abnormal discs or recurrent pain from a prior operation or disc herniation, and to assess whether a patient with a known disc herniation is a suitable candidate for minimally invasive corrective surgery. It can also be used to assess discs prior to spinal fusion to ensure the discs belonging to the proposed fusion area are symptomatic and suitable for a fusion.
During a discography procedure, a long needle is inserted into the center of the intervertebral disc. Prior to the procedure, the skin around the painful area will be sanitized to decrease the risk of infection. A small injection of local anesthetic will be used to numb the area before a larger needle is inserted. Real time x-ray (fluoroscopy) is used in order to ensure proper placement of the larger needle and assess the internal structure of the discs.
Through the larger needle, a special dye (contrast medium) is injected into the disc, making the disc visible on x-ray film. This is called a discogram. Pressure created by the injection is used to determine whether the disc being tested is causing the patient’s pain. Based upon the results of the patient’s discogram, the physician will suggest what he or she believes to be the optimal course of treatment.
A discography study generally takes approximately one half to one hour. To further check disc morphology, the doctor may order a CT scan directly after the discogram while the dye is still in effect.
In general, diagnostic studies such as MRI and CT scans show anatomical dysfunctions whereas discography is able to pinpoint specific structures producing the pain. Further, discography can provide unique information about the pain source and the morphology of a spinal disc[5]. For example, a study of 7 patients with surgically proven internal disc disruption and normal MRI reported the patients’ discograms showed morphological abnormalities; the researchers concluded discography may be useful in patients with persistent symptoms despite normal or equivocal MRIs[6]. Further, a 2007 study declared discography is more effective than MRI for detecting intervertebral disc ruptures[7].
Clinical research backs the efficacy of discography as a diagnostic tool. Systematic reviews of the literature have concluded discography may be an important imaging and pain evaluation tool for evaluating lumbar (low back) and cervical (neck) discogenic pain secondary to intervertebral disc disorders[8],[9],[10]. In a prospective study in 250 individuals with low back pain, the combination of discography and CT scan provided significant information regarding equivocal or multiple level abnormalities and type of herniation, defining surgical options, and evaluating previously operated spines in 93% of the patients[11]. In 94% of individuals enrolled in the study, discography/CT correctly predicted disc herniation as protruded, extruded, sequestrated, or internally disrupted. And a prospective study of 279 injected discs in 100 patients found exact reproduction of pain on injection was more common in fissured or ruptured discs than in less degenerated discs, and the results indicated discography had a sensitivity of 81% and specificity of 64% for pain [12]. Additional information yielded by follow-up CT scan was minimal.
As with all medical procedures, patients who undergo discography are subject to the risk of developing complications. However, discography is considered a low risk procedure and reported complications tend to be minimal.
Risks of discography may include bleeding, hematoma, cerebrospinal fluid leakage, headache and increased pain. In addition, one study found an association between discography and new disc herniation[13]. Discitis, a painful infection of the disc, has also been reported, although the authors of a recent meta-analysis concluded the incidence of discitis after discography is relatively low[14].
After the results from a discography study are reviewed, the pain physician will devise a treatment plan intended to increase the patient’s level of function as well as decrease or eliminate pain.
Louisiana Pain Specialists understands the burden of living with a painful condition and strives to help patients regain their quality of life. Our caring practitioners are dedicated to working closely with patients to create individualized pain management programs designed to restore good health and happiness. To investigate treatment options for refractory back pain, call to schedule an appointment with us today.
[1] Stout A. (2010). Discography. Phys Med Rehabil Clin N Am., 21(4), 859-67
[2] Buenaventura RM, Shah RV, Patel V, Benyamin R, & Singh V. (2007). Systematic review of discography as a diagnostic test for spinal pain: an update. Pain Physician., 10(1), 147-64.
[3] Kallewaard JW, Terheggen MA, Groen GJ, Sluijter ME, Derby R, Kapural L, Mekhail N, & van Kleef M. (2010). 15. Discogenic low back pain. Pain Pract., 10(6), 560-79.
[4] Smith, LJ, Nerurkar, NL, Choi, KS, Harfe, BD, & Elliott, DM. (2011). Degeneration and regeneration of the intervertebral disc: lessons from development. Dis Model Mech., 4(1), 31-41.
[5] Zhou Y, & Abdi S. (2006). Diagnosis and minimally invasive treatment of lumbar discogenic pain–a review of the literature. Clin J Pain., 22(5), 468-81.
[6] Brightbill TC, Pile N, Eichelberger RP, & Whitman M Jr. (1994). Normal magnetic resonance imaging and abnormal discography in lumbar disc disruption. Spine (Phila Pa 1976)., 19(9), 1075-7.
[7] Montes García C, & Nava Granados LF. (2007). [Evocative lumbar discography][Article in Spanish]., Acta Ortop Mex., 21(2), 85-9.
[8] Manchikanti L, Glaser SE, Wolfer L, Derby R, & Cohen SP. (2009). Systematic review of lumbar discography as a diagnostic test for chronic low back pain. Pain Physician., 12(3), 541-59.
[9] Buenaventura RM, Shah RV, Patel V, Benyamin R, & Singh V. (2007). Systematic review of discography as a diagnostic test for spinal pain: an update. Pain Physician., 10(1), 147-64.
[10] Manchikanti L, Dunbar EE, Wargo BW, Shah RV, Derby R, & Cohen SP. (2009). Systematic review of cervical discography as a diagnostic test for chronic spinal pain. Pain Physician., 12(2), 305-21.
[11] Bernard TN. Lumbar discography followed by computed tomography. Refining the diagnosis of low-back pain. Spine., 15(7), 690-707.
[12] Antti-Poika I, Soini J, Tallroth K, Yrjönen T, & Konttinen YT. (1990). Clinical relevance of discography combined with CT scanning. A study of 100 patients. J Bone Joint Surg Br., 72(3), 480-5.
[13] Carragee EJ, Don AS, Hurwitz EL, Cuellar JM, Carrino JA, & Herzog R. (2009). 2009 ISSLS Prize Winner: Does discography cause accelerated progression of degeneration changes in the lumbar disc: a ten-year matched cohort study. Spine (Phila Pa 1976)., 34(21), 2338-45.
[14] Kapoor SG, Huff J, & Cohen SP. (2010). Systematic review of the incidence of discitis after cervical discography. Spine J. 10(8), 739-45.
