Diagnostic relevance of pressure-controlled discography

Frequency of use of discography findings for the diagnosis of low back pain of discogenic origin. Systematic review of the literature

INTRODUCTION

There are different techniques and interpretations of discography findings to determine it positive for the diagnosis of discogenic pain. This study aims to evaluate the frequency of use of discography findings for the diagnosis of low back pain of discogenic origin.

MATERIAL AND METHODS

A systematic review of the literature of the last 17 years was performed in MEDLINE and BIREME. A total of 625 articles were identified, 555 were excluded for duplicates, title and abstract. We obtained 70 full texts of which 36 were included in the analysis after excluding 34 for not meeting the inclusion criteria.

RESULTS

Among the criteria in discography to determine it as positive, 8 studies used only the pain response to the procedure, 28 studies used more than one criterion during discography to consider it as positive, the evaluation of at least one adjacent intervertebral disc with a negative result was necessary in 26 studies to consider a discography as positive. Five studies formally expressed the use of the technique described by SIS/IASP to determine a discography as positive.

CONCLUSIONS

Pain in response to contrast medium injection, assessed with the visual analog pain scale≥6, was the most used criterion in the studies included in this review. Although there are already criteria to determine a discography as positive, the use of different techniques and interpretations of discography findings to determine a positive discography for low back pain of discogenic origin persists.

[Translated article] Frequency of use of discography findings for the diagnosis of low back pain of discogenic origin. Systematic review of the literature

INTRODUCTION

There are different techniques and interpretations of discography findings to determine it positive for the diagnosis of discogenic pain. This study aims to evaluate the frequency of use of discography findings for the diagnosis of low back pain of discogenic origin.

MATERIAL AND METHODS

A systematic review of the literature of the last 17 years was performed in MEDLINE and BIREME. A total of 625 articles were identified, 555 were excluded for duplicates, title and abstract. We obtained 70 full texts of which 36 were included in the analysis after excluding 34 for not meeting the inclusion criteria.

RESULTS

Among the criteria in discography to determine it as positive, 8 studies used only the pain response to the procedure, 28 studies used more than one criterion during discography to consider it as positive, the evaluation of at least one adjacent intervertebral disc with a negative result was necessary in 26 studies to consider a discography as positive. Five studies formally expressed the use of the technique described by SIS/IASP to determine a discography as positive.

CONCLUSIONS

Pain in response to contrast medium injection, assessed with the visual analogue pain scale ≥6, was the most used criterion in the studies included in this review. Although there are already criteria to determine a discography as positive, the use of different techniques and interpretations of discography findings to determine a positive discography for low back pain of discogenic origin persists.

Automated Pressure-Controlled Discography in Patients Undergoing Anterior Lumbar Interbody Fusion for Discogenic Back Pain

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To compare the clinical outcomes of patients undergoing anterior lumbar interbody fusion (ALIF) with or without automated pressure-controlled discography (APCD) before the procedure.

METHODS

Patients (n = 36) who underwent ALIF for lumbar discogenic back pain between 2008 and 2013 and were followed for more than 6 months were enrolled in this study. APCD was performed to identify discogenic back pain. Preoperative x-rays, computed tomography images, and magnetic resonance images were obtained. The intervertebral disc height, type of Modic change, grade of disc degeneration, and fusion rate were determined. Additionally, the presence or absence of high-intensity zone and vacuum disc were checked preoperatively. Clinical evaluation was performed by visual analog scale (0 = no pain, 10 = worst pain imaginable), Oswestry Disability Index (ODI), and 36-Item Short Form Health Survey before surgery and every 6 months postoperatively.

RESULTS

The average patient age was 53.3 years (range, 31-73 years). The mean follow-up durations were 19.7 months. Seventeen patients (the APCD-ALIF group) underwent ALIF after APCD, and 19 patients underwent ALIF without APCD. The APCD-ALIF group had significantly improved clinical outcomes compared with the control group (visual analog scale score 1.8 ± 1.6 vs. 3.3 ± 2.4; P = 0.039: ODI score 6.7 ± 6.3 vs. 12.1 ± 6.8; P = 0.019). The surgical improvement rate was significantly associated with ODI score (P = 0.005).

CONCLUSIONS

The results of this study confirm that APCD aids surgical outcomes of ALIF in patients with suspected lumbar discogenic pain. We recommend performing APCD before ALIF to confirm lumbar discogenic pain.

Intradiscal Microprobe With a Vibrational Optical Fiber for Diagnosis and Thermal Therapy of Discogenic Pain Due to an Annular Fissure

Major studies have shown that discogenic pain is the most common cause of chronic lower back pain, accounting for 40% of all the causes. Provocation discography—inducing pains by pressing nerve structures around the annular fissures—is recognized as the only method for diagnosing discogenic pain. However, the method is not available to the patient with full-thickness fissures because of a contrast media leakage through the fissure. In this paper, intradiscal microprobes (IDMPs) affecting direct mechanical stimulus on the nerve fiber are presented for diagnosis of the fissure. The plastic optical fiber (POF), located in the flexible polymer tube, can be navigated to fissure vicinities. Then, a linear or rotational motor placed inside the probe grip generates a minute axial or radial vibration of the fiber tip, which irritates the tiny pain nerve fiber around the fissure. The intensity of the pain can serve as a guideline to determine the level of discogenic disease. The frequency and amplitude of the axial (radial) vibration discography were 2.9–5.7 (4.0–7.0) Hz and 1.5–3.4 (0.06–3.25) mm, respectively. Furthermore, the optical experiments for evaluation of thermal therapy application were successfully confirmed.

The transfer of disc pressure to adjacent discs in discography: a specificity problem?

STUDY DESIGN

In vivo experimental study.

OBJECTIVE

The primary objective of the study was to investigate pressure transmission to adjacent discs during discography. A secondary objective was to quantify the transmitted pressure, both in contrast injected and noninjected porcine intervertebral discs.

SUMMARY OF BACKGROUND DATA

Discography is used to before surgery identify painful discs. A pain response during discography that is concordant with the patient's experienced back pain is regarded as an indication that the injected disc is the source of pain. However, the sensitivity and specificity of discography are matters of debate. Pressure-controlled discographies have been reported to reduce the number of false-positive discs using low pressure criteria. Preliminary data indicated a transfer of pressure from an injected to an adjacent disc during discography. Pressure transmission in vivo during lumbar discography, not reported before might, if clinically present, contribute to a false-positive diagnosis.

METHODS

Thirty-six lumbar discs in 9 adolescent pigs were investigated. Intradiscal pressure was recorded during contrast injection, using a 0.36/0.25 mm fiber-optic pressure transducer inserted into the nucleus pulposus via a 22 G needle. The pressure was measured simultaneously in 2 adjacent discs during contrast injection into 1 of the discs at pressures up to 8 bar. Transmitted pressure was recorded both in noninjected discs and in discs that were prefilled with contrast.

RESULTS

Thirty-three discs were successfully examined. During contrast injection, there was an intradiscal pressure rise in the adjacent disc with a median value of 16.0% (range, 3.2-37.0) over baseline pressure. There was no significant difference in pressure increase between the noninjected and prefilled discs (P < 0.68).

CONCLUSION

Discography of porcine discs induces a pressure increase in adjacent discs. A similar pressure transfer during human clinical discography might elicit false-positive pain reactions.

Clinical and radiological findings of discogenic low back pain confirmed by automated pressure-controlled discography

OBJECTIVE

Few studies on the clinical spectrum of automated pressure-controlled discography (APCD)-defined positive discs have been reported to date. Thus, the present study was undertaken to analyze clinical parameters critical for diagnosis of discogenic pain and to correlate imaging findings with intradiscal pressures and pain responses in patients with APCD-positive discs.

METHODS

Twenty-three patients who showed APCD-positive discs were selected for analysis. CT discogram findings and the degrees of nuclear degeneration seen on MRI were analyzed in comparison to changes of intradiscal pressure that provoked pain responses; and clinical pain patterns and dynamic factors were evaluated in relation to pain provocation.

RESULTS

Low back pain (LBP), usually centralized, with diffuse leg pain was the most frequently reported pattern of pain in these patients. Overall, LBP was most commonly induced by sitting posture, however, standing was highly correlated with L5/S1 disc lesions (p < 0.01). MRI abnormalities were statistically correlated with grading of CT discogram results (p < 0.05); with most pain response observed in CT discogram Grades 3 and 4. Pain-provoking pressure was not statistically correlated with MRI grading. However, it was higher in Grade 3 than Grade 4.

CONCLUSION

APCD-positive discs were demonstrated in patients reporting centralized low back pain with diffuse leg pain, aggravated by sitting and standing. MRI was helpful to assess the degree of nuclear degeneration, yet it could not guarantee exact localization of the painful discs. APCD was considered to be more useful than conventional discography for diagnosis of discogenic pain.

Factors influencing manometric pressure during pressure-controlled discography

STUDY DESIGN

In vitro laboratory study.

OBJECTIVE

The aim of this study was to evaluate the effects of injection speed, contrast viscosity, and needle profile on manometric pressures during discography.

SUMMARY OF BACKGROUND DATA

As the degree of the response in a provocation test depends on the intensity of the stimulus, the precise measurement of intradiscal pressure during discography is crucial. Although manometric pressure measurement is safe and easy, manometric pressures may be affected by potential confounding factors, including injection speed, contrast viscosity, and needle profile.

METHODS

Pressure-controlled discography was performed using an automated pressure-controlled discography system in a total of 60 intervertebral discs in 2 porcine cadavers. Dynamic pressures were measured while changing the following parameters: injection speed (0.01 mL/s vs. 0.08 mL/s), media viscosity (Visipaque vs. normal saline), needle diameter (18G vs. 22G), and needle length (7 inch vs. 3.5 inch). The unit change in manometric pressure per fractional change in injected volume (dP/dV) was used for statistical analysis.

RESULTS

The mean dP/dV increased from 137.9 +/- 11.3 at 0.08 mL/s to 160.3 +/- 12.5 at 0.01 mL/s. Visipaque injection resulted in a higher mean dP/dV than the normal saline injection (160.3 +/- 12.5 vs. 97.8 +/- 34.1). A 7.5 inch needle had a higher mean dP/dV than a 3.5 inch needle (137.9 +/- 11.3 vs. 92.5 +/- 48.6). The mean dP/dV of the 22G needle was higher than the 18G needle (137.9 +/- 11.3 vs. 84.7 +/- 28.3).

CONCLUSION

High injection speed, high viscosity, small diameter, and a long needle increase the dynamic pressure. To minimize the differences among examiners, we recommend standardization of injection speed, the viscosity of the injected material, and the diameter and length of the needle.

Automated pressure-controlled discography with constant injection speed and real-time pressure measurement

OBJECTIVE

This study was designed to investigate automated pressure-controlled discography (APCD) findings, to calculate the elastance of intervertebral discs, and to assess the relationship between the calculated elastance and disc degeneration.

METHODS

APCD was performed in 19 patients. There were a total of 49 intervertebral discs treated. Following intradiscal puncture, a dye was constantly injected and the intradiscal pressure was continuously measured. The elastance of the intervertebral disc was defined as unit change in intradiscal pressure per fractional change in injected dye volume. Disc degeneration was graded using a modified Dallas discogram scale.

RESULTS

The mean elastance was 43.0 +/- 9.6 psi/mL in Grade 0, 39.5 +/- 8.3 psi/mL in Grade 1, 30.5 +/- 22.3 psi/mL in Grade 2, 30.5 +/- 22.3 psi/mL in Grade 3, 13.2 +/- 8.3 psi/mL in Grade 4 and 6.9 +/- 3.8 psi/mL in Grade 5. The elastance showed significant negative correlation with the degree of degeneration (R(2) = 0.529, p = 0.000).

CONCLUSION

APCD liberates the examiner from the data acquisition process during discography. This will likely improve the quality of data and the reliability of discography. Elastance could be used as an indicator of disc degeneration.