Discography, also known as provocative discography, has been used in the diagnosis of cervical and, to a limited extent, thoracic pain syndromes in individuals being considered for surgical intervention.  The contemporary use of discography involves a pressure-monitored injection of one to three (1-3) ml of contrast agent through a fine needle introduced into the center (nucleus pulposus) of an intervertebral disc followed by CT imaging to evaluate the nature and extent of suspected abnormal vertebral disc morphology.  The rationale is that if a disc is symptomatic, stressing that disc will reproduce the individual's pain while stressing adjacent discs will not.  The objective is to characterize the pain response (if any) on disc injection and observe whether discographic pain is concordant, i.e. able to reproduce the individual's pain syndrome.

NOTE:  This document is limited to the discussion of cervical and thoracic discography. For information on lumbar discography, refer to CG-SURG-29 Lumbar Discography.

Investigational and Not Medically Necessary: 

Cervical and thoracic discography are each considered investigational and not medically necessary for all indications.

Introduction
Although the technique of cervical discography was first described decades ago (Cloward, 1963), the value of cervical and thoracic discography has been explored in only a small number of studies and remains unproven.  Shah et al (2005) and Buenaventura et al (2007) performed extensive reviews of the literature evaluating the diagnostic accuracy of discography in the management of chronic spinal pain.  Studies were scored according to the Agency for Healthcare Research and Quality (AHRQ; West S, et al 2002) and Quality Assessment of Diagnostic Accuracy (QUADAS; Whiting, 2003) rating scales for diagnostic testing.  For inclusion, studies first had to meet at least 50% of the total possible points for each scale.  Evidence was then classified into five levels: conclusive, strong, moderate, limited, or indeterminate.  The authors concluded in their review of the evidence through November 2006 that there is only "moderate" evidence supporting the role of discography in identifying a subset of individuals with cervical discogenic pain and only "limited" evidence supporting the role of discography in identifying individuals with thoracic discogenic pain.  In their review, the authors defined "moderate" evidence as evidence obtained from comparative studies with non-randomized concurrent or historical controls, single arm trials or interrupted time series without a parallel control group.  "Limited" evidence was defined as well-designed non-experimental studies from more than one center or research group; or conflicting evidence with inconsistent findings in multiple trials.

Thoracic Discography
While discography of the thoracic spine has many similarities to the technique used in the lumbar spine, inadvertent pleural puncture and pneumothorax add to the potential risks of the procedure.  Schellhas and colleagues (1994) analyzed the results of thoracic discograms after MR imaging in a retrospective series of 100 subjects with spinal pain.  There were no serious complications in the series.  They found that approximately 75% of discs with annular tears, intrinsic degeneration, and/or endplate deformities were painful during discography and clinically concordant with the subject's pain approximately 50% of the time.  The authors concluded that thoracic discography can be performed safely as a diagnostic procedure to determine if degenerated discs on MRI are related to clinical symptoms.  The limitations of this study include its retrospective, uncontrolled design.

In a case-control series, 10 asymptomatic volunteers and 10 adults with chronic thoracic pain were studied with MRI of the thoracic spine, followed by four-level discography.  Provocative responses were graded on a scale of 0 to 10 (Wood 1999).  The mean pain response in the asymptomatic volunteers was 2.4/10 and on discography 27 of 40 discs studied in asymptomatic volunteers were abnormal with endplate changes, annular tears, and/or herniations.  Three discs in the asymptomatic group were found to be intensely painful, with all three showing endplate changes (Schmorl's nodes) and annular tears typical of Scheuermann's disease (juvenile kyphosis).  In the group with chronic thoracic pain, the average pain response was 6.3/10 (P<0.05).  Of the 46 discs studied in the symptomatic individuals, 24 were concordantly painful (reproduced the subject's chronic pain syndrome) while 17 had non-concordant pain/pressure and 5 had no response.  In the asymptomatic control group, 10 of 40 discs which appeared normal on MRI showed annular pathology on discography.  In the symptomatic group 21 of 48 discs were judged normal on MRI.  However, on discography only 10 were judged as normal.  The authors concluded that thoracic discography may demonstrate disc pathology not seen on MRI, but the study was limited by its small size and was not designed to demonstrate a clinical outcome benefit of thoracic discography in the management of individuals with chronic spinal pain.

In 2008, Singh and colleagues undertook a systematic review of thoracic discography and identified the same two articles for review.  The authors characterized these two studies as II-3, i.e. evidence obtained from diagnostic studies of uncertainty, and concluded that these studies supported a weak recommendation based on low quality or very low quality evidence. 

Cervical Discography
Cervical discography has been recommended as a tool to identify specific intervertebral levels causing neck pain as a guide to pre-operative cervical fusion planning for individuals with axial neck pain and cervical spondylosis (Wieser, 2007).  Cervical discography has been recommended for those individuals who have multilevel disc disease when the offending disc cannot be identified.  Although cervical discography has been considered by some to be a useful diagnostic tool, it has been criticized by others for failing to contribute unique information beyond that available from standard imaging studies despite its inherent risks.  The risk of disc space infection following cervical discography has been reported to range from 1% to 4% (Guyer, 1997; Osti, 1990).  Additional complications associated with discography include spinal cord injury, hematoma and rare reports of epidural abscess with quadriplegia (Connor, 1993).

Pafenchuck and colleagues (1994) studied the correlation between discography and MRI in 52 participants with cervical discogenic pain.  They found no correlation between either pain response or morphology as seen on discography and MRI.  They observed that while some MRI patterns do correlate well with positive or negative cervical discography, several other MRI patterns are equivocal.  They concluded that MRI may be a useful adjunct to discography, but that some MRI findings cannot be considered pathologic, and discography is required to diagnose discogenic pain syndrome in those individuals.

Schellhas et al (1996) reported a small prospective correlation of MRI and discography in individuals with asymptomatic and chronic neck pain.  Ten asymptomatic participants and ten "non-litigious" chronic neck pain participants underwent cervical discography after magnetic resonance imaging.  Disc morphology and provoked responses were recorded at each level studied C3-C7.  In the asymptomatic group, 17 of 20 discs found to be normal on MRI had painless annular tears on discography.  In the symptomatic group, 11 of 40 discs appeared normal on MRI while 10 of these showed annular tears on discography.  Two of the 10 discs in symptomatic individuals (MRI normal, but discography abnormal) were concordantly painful with intensity ratings of at least 7/10.  In this small study, the authors reported that discographically normal discs (N=8) were never painful in either group, while intensely painful discs on discography had tears of both the inner and outer disc annulus.  They concluded that significant cervical disc annular tears are often missed on MRI, and that MRI cannot reliably identify the source(s) of cervical discogenic pain.  Although prospective in design, this study is limited by its very small size.

Zheng and colleagues (2004) looked at the correlation between MRI and cervical discography in degenerative disc disease in 55 individuals with cervical discogenic pain.  All participants went on to anterior cervical discectomy and fusion, and postoperative pain relief was assessed by the participants.  Successful cervical fusion was achieved in 95% of individuals, and the overall satisfactory result was reported at 76 %.  In this study, 161 cervical discs were studied with discography and 79 levels were positive.  Of 79 discs with positive discography, only 58 (73%) had an abnormal MRI.  Of 82 levels studied with negative discography, only 40 (49%) had a normal MRI.  From these observations, the authors concluded that a combination of clinical symptoms, MRI, and discography provided the most information for decision making and can improve the management of cervical discogenic pain.  The limitations of this study include its retrospective design and lack of a randomized control.

Two reviews of cervical discography identified only 10 studies meeting a minimal evidence threshold; all but three were retrospective and none included a randomized control (Buenaventura, 2007; Shah, 2005)  In only four of these studies were the sensitivity and specificity for the test calculated.  Carragee et al (2006) and others have questioned the validity of discography in both the lumbar and cervical spine.  They reported that the specificity of discography is dependent upon the psychological profile of the participant.  Nordin and colleagues undertook a broader review of the assessment of neck pain and concluded that no evidence supports using cervical discography in assessing neck pain (Nordin 2008).

Conclusion|
While cervical and thoracic discography may demonstrate disc pathology and concordant pain, there is insufficient evidence from controlled clinical trials to demonstrate a favorable impact on the clinical outcome of individuals with discogenic pain in either the cervical or thoracic spine.  The American Society of Interventional Pain Physicians' evidence based practice guidelines in the management of chronic spinal pain (Boswell, 2007) concluded that the evidence is limited for both cervical and thoracic discography.  In addition, the American College of Radiology's panel on musculoskeletal imaging for chronic neck pain does not recommend cervical discography for the evaluation of individuals with cervical spondylosis, assigned the procedure an appropriateness criterion of 1, signifying the least appropriate test (ACR, 2010).

While discography has been studied extensively in the lumbar spine, it has been evaluated less so in cervical discs, and even less frequently in thoracic discs.  At this time, there is not sufficient evidence from controlled trials to evaluate whether cervical and thoracic discography result in improved outcomes in individuals with chronic cervical or thoracic spine pain.  Until there is more scientific evidence demonstrating the efficacy and improved outcomes with this test for individuals experiencing cervical or thoracic pain, the clinical value and diagnostic utility of cervical and thoracic discography remain unproven.

Discography involves the pressure-controlled injection of a water-soluble contrast material directly into the center (nucleus pulposus) of the vertebral disc.  Information is then documented about the amount of dye accepted, the pressure necessary to inject the material, the pattern of the opaque material, and the reproduction of the individual's pain.  For a response to be considered positive, concordant pain must be produced; and for the test to be considered valid, there must be at least one or more discs that do not elicit pain upon injection which serve as an internal control.  Discography is a procedure used to characterize the architecture of the intervertebral disc and to determine if the disc is a cause of an individual's chronic spinal pain.  Since discography is an invasive diagnostic test, it is generally reserved for chronic spinal pain in individuals refractory to conservative therapies in whom disc pathology is felt to be a likely cause of the individual's pain and surgery is being considered.  While lumbar discography may be of value in the treatment planning of individuals with discogenic low back pain (see CG-SURG-29 Lumbar Discography), its utility in the diagnosis and management of cervical and thoracic discogenic pain is less well studied.

The discographer relies only on pain reproduction from a suspected disc, and with a positive response the results may be either true-positive or false-positive.  Those skeptical of the utility of discography suggest that discography may reveal the subclinical potential of a disc with abnormal morphology to cause pain, but contend that does not prove that the disc is actively a source of the individual's complaints.  Lacking are randomized, prospective controlled trials demonstrating the results of cervical and thoracic discography can be used to achieve improved clinical outcomes.

The following codes for treatments and procedures applicable to this document are included below for informational purposes.  Inclusion or exclusion of a procedure, diagnosis or device code(s) does not constitute or imply member coverage or provider reimbursement policy.  Please refer to the member's contract benefits in effect at the time of service to determine coverage or non-coverage of these services as it applies to an individual member.

When services are Investigational and Not Medically Necessary:

Peer Reviewed Publications:

1. Ahn Y, Lee SH, Chung SE, Park HS, Shin SW. Percutaneous endoscopic cervical discectomy for discogenic cervical headache due to soft disc herniation. Neuroradiology. 2005; 47(12):924-930.
2. Boswell MV, Trescot AM, Datta, et al. Interventional Techniques: Evidence-based practice guidelines in the management of chronic spinal pain. Pain Phys. 2007; 10(1):7-111.  Available at:  http://www.painphysicianjournal.com/2007/january/2007;10;7-111.pdf  Accessed on December 16, 2010.
3. Buenaventura RM, Shah RV, Patel V, et al. Systematic review of discography as a diagnostic test for spinal pain: an update. Pain Physician. 2007; 10(1):147-164.
4. Carragee EJ, Alamin TF: Low pressure positive Discography in subjects asymptomatic of significant low back pain illness. Spine J. 2006; 1(5):364-372.
5. Connor PM, Darden BV Cervical discography complication and clinical efficacy. Spine 1993; 18:2035-2038. 15:18(14):2035-2038.
6. Grubb SA, Kelly CK. Cervical discography: clinical implications from 12 years of experience. Spine. 2000; 1: 25(11):1382-1389.
7. Guyer RD, Ohnmeiss DD, Mason SL, Shelokov AP. Complications of cervical discography: findings in a large series. Spinal Disord. 1997; 10(2):95-101.
8. Hamasaki T, Baba I, Tanaka S, et al. Clinical characterizations and radiologic findings of pure foraminal-type cervical disc herniation: CT discography as a useful adjuvant in its precise diagnosis. Spine. 2005; 30(20):E591-596.
9. Madan S, Gundanna M, Harley JM, et al. Does provocative discography screening of discogenic back pain improve surgical outcome? Journal of Spinal Disorders Techniques. 2002; 15(3): 245-251.
10. Manchikanti L, Boswell MV, Singh V, et al. Comprehensive evidence-based guidelines for interventional techniques in the management of chronic spinal pain. Pain Physician. 2009; 12(4):699-802. 
11. Manchikanti L, Dunbar EE, Wargo BW et al. Systematic review of cervical discography as a diagnostic test for chronic spinal pain. Pain Physician. 2009; 12(2):305-321.
12. Motimaya A, Arici M, George D, Ramsby G. Diagnostic value of cervical discography in the management of cervical discogenic pain. Conn Med. 2000; 64(7):395-398. 
13. Nordin M, Carragee EJ, Hogg-Johnson S et al.  Assessment of neck pain and its associated disorders: results of the Bone and Joint Decade 2000-2010 Task Force on Neck Pain and Its Associated Disorders.  Spine. 2008; 33(4 Suppl):S101-122.
14. Osti OL, Fraser RD, Vernon-Roberts F Discitis after discography. J Bone Joint Surgery Br. 1990; 72(2):271-274.
15. Parfenchuck TA, Janssen ME. A correlation of cervical magnetic resonance imaging and discography/ computed tomographic discograms. Spine. 1994; 19(24):2819-2825.
16. Schellhas KP, Pollei SR, Dorwart RH Thoracic discography. A safe and reliable technique. Spine. 1994; 19(18):2103-2109.
17. Schellhas KP, Smith MD, Gundry CR, Pollei SR. Cervical discogenic pain. Prospective correlation of magnetic resonance imaging and discography in asymptomatic subjects and pain sufferers. Spine. 1996; 21(3):300-311.
18. Shah RV, Everett C, McKenzie-Brown A, Sehgal N. Discography as a diagnostic test for spinal pain: A systematic and narrative review. Pain Physician. 2005; 8(2):187-209.
19. Singh V, Manchikanti L, Shah RV, et al.  Systematic review of thoracic discography as a diagnostic test for chronic spinal pain. Pain Physician. 2008; 11(5):631-642.
20. Slipman CW, Plastaras C, Patel R. Provocative cervical discography symptom mapping. Spine J. 2005; 5(4):381-388.
21. Whiting P, Rutjes AW, Reitsma JB, et al. The development of QUADAS: a tool for the quality assessment of studies of diagnostic accuracy included in systematic reviews. BMC Med Res Methodol. 2003; 3:25. Available at: http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1421422&blobtype=pdf  Accessed on December 16, 2010.
22. Wieser ES, Wang JC. Surgery for neck pain. Neurosurgery. 2007; 60(1 Supp1 1):S51-56.
23. Wood KB, Schellhas, Garvey TA, Aeppli D. Thoracic discography in healthy individuals.  A controlled prospective study of magnetic resonance imaging and discography in asymptomatic and symptomatic individuals. Spine. 1999; 24(15):1548-1555.
24. Zheng Y, Liew SM, Simmons ED. Value of magnetic resonance imaging and discography in determining the level of cervical discectomy and fusion. Spine. 2004; 29(19):2140-2145

Government Agency, Medical Society, and Other Authoritative Publications:

1. American College of Radiology (ACR) Appropriateness Criteria Chronic neck pain. ACR 2010.  Available at: http://www.acr.org/SecondaryMainMenuCategories/quality_safety/app_criteria/pdf/ExpertPanelonMusculoskeletalImaging/ChronicNeckPainDoc9.aspx. Accessed on December 16, 2010.
2. West S, King V, Carey TS, et al. Systems to rate the strength of scientific evidence. Evidence Report/Technology Assessment No. 47.  Evid Rep Technol Assess (Summ). 2002; (47):1-11. Available online at: http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=hstat1.chapter.70996. Accessed on December 16, 2010.

Cervical Discography
Thoracic Discography