Discogenic Back Pain: Pathophysiology and Treatment

Transcription

1 The 33 rd Annual Spring Meeting of KNS, 2015 Evidence-Based Approach of Spinal Pain Discogenic Back Pain: Pathophysiology and Treatment Ki-Jeong Kim M.D. Department of Neurosurgery, Spine Center, Seoul National University Bundang Hospital

2 Nomenclature Discogenic back pain Pain innate to intervertebral disc A damaged vertebral disc, particularly degenerative changes of IVD Internal disc disruption A condition characterized by degradation of the nuclear matrix and the development of fissures inside the disc. Histologic term Degenerative disc disease Various conditions related with degeneration of an IVD Painful degenerative disc disease discogenic back pain

3 Internal Disc Disruption Crock HV (1970) A distinct clinical entity with respect to other painful processes Such as segmental instability, disc prolapse, DDD, etc Morphologic features Annular tears Degradation of nucleus matrix Disc collapse with endplates failure Absence of significant modifications of the disc external contour No compression of nervous elements.

4 Disc Structural Failure Anular tears Disc prolapse Endplate damage & Schmorl s nodes Internal disc disruption Disc narrowing, radial bulging, & osteophytes MA Adams, PJ Roughley, Spine, 2006

5 Pain Mechanism Mechanical transduction of nociception Internally disrupted disc depressurized NP stress in posterior anulus Chemical nociception Degraded matrix material inflammatory mediators, cytokine, noxious agents Neo-innervation Along with radial fissures (Freemont AJ et al, 1997)

6 Painful vs. Non-painful disc IDD disc degeneration Different composition and structure of painful disc from non-painful degenerated disc Independent condition starting as a focal disorder of AF The histological hallmarks of painful disc Annulus radial tears Radial fissures occur at an earlier age than degenerative changes Prevalence does not increase over time Starting from the external annulus, densely vascularized and innervated granulation tissue develops along the radial fissures

7 Radial Fissure Visualization through injecting contrast medium into the NP Strong correlation between a disc w/ grade 3 or 4 fissure and being painful upon disc stimulation (Moneta GR et al., 1994) Radial fissure: independent of age

8 Prevalence IDD in chronic low back pain: 26 42%

9 Symptoms Triggering activities: pressure within the disc space Standing or sitting for prolonged periods Leaning forward Sneezing and coughing Provocation of pain when rising from sitting Location of pain Centralization: midline back pain, competent anulus High sensitivity, poor specificity Peripheralization: leg pain anular breach

10 Diagnosis Discogenic pain is not amenable to conventional means of assessing diagnostic tests Pain is a physiological symptom It cannot be photographed, radiographed, or biopsied. No physical reference standard for discogenic pain

11 Provocation Discography Reproduction of patients back pain was reproduced when contrast medium was injected into certain discs Pressure threshold & symptom (O Neill C et al. 2001, 2004) 3 subgroups of response: Low-pressure group distinct symptomatic disc Mid-pressure group High-pressure group normal disc

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13 IASP guideline for provocation discogrphy Concordant pain 7/10 Pressure < 50 psi Grade 3 anular tear Volume limit 3.5 ml A painless control disc

14 False Positive in Asymptomatic False-positive rate for asymptomatic subjects 3.0% (95 CI 0 9%) per patient 2.1% (95% CI 0 6%) per disc Reliable test with a low false-positive rate in asymptomatic volunteers without confounding factors

15 High Signal Intenistity Zone in MRI HIZ: Oveall 1658 cases: sensitivity 45%, specificity 88%, Likelihood ratio 3.8 (95% CI: ) HIZ is not absolutely diagnostic of a painful disc Its presence substantially increases the chances that the affected disc will be the source of pain.

16 Modic changes Type 1: inflammatory edema Associated with disruption and fissuring of the endplate, IL-6, IL-8, PGE2 Resolve or evolve into type 2 Type 2: fatty infiltration, persist and not change in appearance Pain: type 1 and 2, not type 3 Patients with CLBP: 19-59% prevalence, median 6% OR of type 1 & 2 in LBP: Type 1 & 2: correl w/ painful disc stimulation LR 3.4 (95% CI: )

17 Diagnostic Tools 53 articles,where IVD itself was considered the principal source of patient s pain and was the main target of the treatment.

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20 Treatment options Medications Physiotherapy Exercise Injection procedures Intradiscal Epidural Surgery Thermal Anular Procedures (TAP) Fusion Artificial disc replacement

21 Intradiscal injection Steroid Positive results Feffer HL (1969) & Wilkinson HA et al. (1980) RCT: Simmons JW et al. (1992) Khot A et al (2004) No significant different between 2 groups

22 Epidural injections Mechanism of action Steroid or local anesthetics: not well understood Neural blockade: interrupts nociceptive input, etc Corticosteroids: reduce infammation Routes Caudal Interlaminar Transforaminal No data was available to assess the evidence.

23 Caudal epidural injections Evidence: fair (Evidence is sufficient to determine effects on health outcomes, but the strength of the evidence is limited by the number, quality, size, or consistency of included studies)

24 Interlaminar injection Evidence: fair for short-term and long-term relief with steroids or with local anesthetic.

25 Thermal Anular Procedures (TAP) Intradiscal electrothermal treatment (IDET) disctrode Biacuplasty

26 Therapeutic Concepts of TAPs Application of heat across the damaged annulus To denervate the annulus, leading to pain relief (Mazin, 2010). The heat reconfigures collagen structure (Derby, 2003).

27 IDET 1996 by Saal JS et al. Heat to the posterior annulus using convection technology 5 cm active tip placed at the nucleoannular junction

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29 Evidence supporting the efficacy of IDET is limited to fair. Positive result: 1 randomized, 4 observational studies Negative result: 1 randomized (poor), 1 observational studies Undetermined: 1 observational study

30 disctrode 2005 by Finch PM et al. Heat to the posterior annulus using ionic heating created by a monopolar radiofrequency device

31 Evidence of disctrode is limited (Evidence is insufficient to assess effects on health outcomes) No benefit: 1 randomized study

32 Biacuplasty 2008 by Kapural L et al. Cooled bipolar radiofrequency device (TransDiscal )

33 Evidence of biacuplasty is limited to fair Positive: 1 randomized trial

34 Lumbar Fusion: 5 RCTs

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36 Fusion vs. non-operative Tx No significant difference when compared with the nonoperative group. Significant improvement in ODI in fusion groups in 3 studies. Overall improvement of 7.39 points (ODI) in favor of lumbar fusion Unclear: clinically significant difference? Either lumbar fusion or non-operative management and physical therapy remain 2 acceptable treatment methods.

37 TDR: 7 RCTs Reference Sample Inclusion Diagnosis Device Fusion Follow up Berg et al. 152 DDD, 1-2 level MRI Charite, Prodisc, Maverick PLF, PLIF 2 yr Blumenthal et al. 304 DDD, single level, L4-S1 Discography Charite BAK 2 yr Gornet et al. 577 DDD, single level, L4-S1 Maverick ALIF (LT-CAGE) Hellum et al. 172 DDD Various device Behavioral Moreno et al. 32 DDD, single level, L4-S1, no instability, Modic 1 or 2 Sasso et al. 67 DDD, single, L1- S1 Charite ALIF 26 mos MR/CT/FEX Flexicore 360 fusion 2 yr Zigler et al. 236 DDD, single, L3- S1 MR/CT/FEX/ discography Prodisc 360 fusion 2 yr

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39 TDR vs. rehab: 1 study Favor of surgery Not reach clinical relevance TDR vs. fusion: 6 studies VAS back (2): higher improvement in TDR, low quality of evidence VAS leg (2): no difference ODI improvement (5): higher in TDR,, low quality of evidence Below the predefined clinically relevant difference: VAS back & ODI

40 Discogenic LBP 26-42% of chronic low back pain Fundamental key for treatment: standard diagnostic measure Provocation discography Most reliable method when properly performed Pressure, volume, radial fissure, control disc False positive rate: 9.3% (per patient), 6.0% (per disc) MRI HIZ: sensitivity 45%, specificity 88%, Likelihood ratio 3.8 Modic change (type 1 & 2): sensitivity 24%, specificity 83%, LR 3.4

41 Evidence of Therapeutic Modalities Procedures Intradiscal steroid injection Caudal epidural injection Interlaminar epidural injection IDET disctrode Biacuplasty Lumbar fusion (vs. non-op) Lumbar TDR (vs. rehab) Lumbar TDR (vs. fusion) Evidence No effect Fair Fair Fair - limited Limited Fair - limited No significant difference ODI improvement: favors fusion Favors TDR, not reach clinical relevance Low quality evidence favors TDR, below clinically relevant difference

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