Annular Tears and HIZ Pain Generation

Written by James Demetrious, DC, DABCO | Board Certified Chiropractic Orthopedist

Sources of Spinal Pain?

Bogduk et al. reported a diagnostic sign of painful lumbar disc, high-intensity zone (HIZ), on T2-weighted magnetic resonance (MR) images and considered that the HIZ, when present, is pathognomonic of an internal annulus disruption and symptomatic intervertebral disc. [1]

Disruption of the internal architecture of the disc can be demonstrated as High-Intensity Zones (HIZ) on MRI. In a recent systematic review, Teraguchi et al. reported that HIZ is of particular interest as it may represent intervertebral disc (IVD) annular tears that are a possible risk factor for lower back pain. [2]

Peng et al. reported that the HIZ of the lumbar disc on MRI in patients with low back pain could be considered a reliable marker of painful outer annular disruption. [3]

Kim et al. reported, “Patients with acute severe axial LBP were more likely to have a disc herniation, LDD, annular tear, and HIZ. Among LBP groups, there was a significant association of HIZ on MRI with acute severe axial LBP.” [4]

Neovascularization, Neoinnervation, Susceptibility, and Pain

Vernon-Roberts et al. report, “Tears may not only perturb disc function and cause segmental instability, but the frequency of neo-vascularization accompanied by neo-innervation indicates that pain originating within the degenerate disc should not be dismissed as the frequent evidence of bleeding into the tear lumen indicates the susceptibility of the vessels to trauma.” [5]

Peng et al. reported in their cohort, “…observed granulation tissue wherein capillary vessels were affluent, and that vascular proliferation and invasion of inflammatory cells were present.” The study found that all of the discs they assessed with HIZ showed painful reproduction and abnormal morphology, with annular tears extending either well into or through the outer third of the annulus fibrosus. [3]

Mechanical Strain

De Geer reports, “High mechanical strain during degeneration could accelerate degeneration and promote neuronal infiltration, thereby contributing to discogenic pain. Excessive mechanical loading can trigger inflammatory and cytokine responses, potentially contributing to spinal disk degeneration and LBP. Asymmetric disk loading can up-regulate the production of cytokine mediators, lowering the threshold response to mechanical load. Exposing disks to IL-1β may render AF cells more vulnerable to injury from excessive load.” [6]

Prevalence of Annular Tears in the Asymptomatic Population

Brinjikji et al. report, “…many imaging-based degenerative features may be part of normal aging and unassociated with low back pain, especially when incidentally seen. These imaging findings must be interpreted in the context of the patient’s clinical condition.” In their paper, they reported a 19%-29% prevalence of annular fissures in their 20-80-year-old asymptomatic cohort. [7]

A Conflict in the Literature

Provocation discography has been identified as a valuable method for the assessment of internal disc disruption and LBP.

Vanharanta et al. reported 790 CT/discograms and discographic pain provocation in 291 patients and found that over 70% of fissures reaching the outer third of the annulus fibrosus (grade 3 disruption of Dallas discogram) were associated with pain reproduction. [8]

Aprill and Bogduk [1] reported, “The prevalence, validity, and reliability of high-intensity zones in the annulus fibrosus seen on T2-weighted magnetic resonance images of patients with intractable low-back pain were determined. Its sensitivity as a sign of either annular disruption or pain was modest, but its specificity was high, and its positive predictive value for a severely disrupted, the symptomatic disc was 86%. This sign is diagnostic of painful internal disc disruption.”

It is puzzling that a more recent study by Wang and Hu conflicts with prior studies. They report, “Our study showed that all the HIZ discs exhibited grade 3 or grade 4 disruptions, but only 9 discs (9/16) were detected with exact pain reproduction. Of the 9 painful and concordant HIZ discs, 8 exhibited grade 4 annular tears.” [9]

Conclusion

Annular tears produce pro-inflammatory cytokines and mediators that can sensitize the nerve endings within the painful discs and cause lower back pain. The HIZ prevalence of symptomatic patients is significantly higher than that of asymptomatic cohorts.

My Thoughts

  1. It is my opinion that the association between lumbar annular HIZ on MR and LBP symptoms is reasonable during inflammatory events.
  2. Moreover, I suspect that inherent anecdotal relief of discogenic pain is associated with inherent segmental motion associated with chiropractic spinal manipulation, flexion distraction technique, and intersegmental traction, providing therapeutic benefit to injured, healing, acute, subacute, and chronic annular tears.

References

  1. Aprill C, Bogduk N. High-intensity zone: a diagnostic sign of painful lumbar
    disc on magnetic resonance imaging. Br J Radiol. 1992;65:361–9.
  2. Teraguchi et al. Scoliosis and Spinal Disorders (2018)13:22.
  3. Peng et al. Eur Spine J (2006) 15: 583–587.
  4. Kim et al. Ann Rehabil Med 2012; 36: 47-54.
  5. Vernon-Roberts et al. Spine. 2007;32(25):2797-804.
  6. De Geer. J Chiropr Med 2018;17:54-62.
  7. Brinjikji et al. AJNR Am J Neuroradiol 36:811–16 Apr 2015. 
  8. Vanharanta et al. Spine: April 1989 – Volume 14 – Issue 4 – p 420-423.
  9. Wang and Hu. Journal of Orthopaedic Surgery and Research (2018) 13:307.

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Disclaimer

The views and opinions expressed in this presentation are solely those of the author. We offer this only to educate and inform.

PostGradDC offers advanced post-graduate chiropractic continuing education. Our founder, Dr. James Demetrious, is an internationally distinguished board-certified chiropractic orthopedist, educator, author, and editor. For current, evidence-based, and clinically intuitive CE Coursework, attain your advanced training at PostGradDC.com.