Analysis of Neuropathic Pain Using Magnetic Resonance Imaging T2 Mapping of Intervertebral Disc in Chronic Low Back Pain

Passive intervertebral restraint is different in patients with treatment-resistant chronic nonspecific low back pain: a retrospective cohort study and control comparison

PURPOSE

In vivo studies of continuous lumbar sagittal plane motion have found passive intervertebral motion to be more uneven in patients with chronic nonspecific low back pain (CNSLBP) than healthy controls, but the mechanisms are unclear. This study aimed to compare patients with CNSLBP with a matched group of pain-free controls for intervertebral restraint during passive recumbent bending.

METHODS

Seventeen patients with CNSLBP and minimal disc degeneration who had quantitative fluoroscopy investigations were matched to 17 healthy controls from a database acquired using the same imaging protocol. The entire database (n = 136) was examined for clustering of peaking times, magnitudes and ROM of the first derivatives of the intervertebral angle/motion curves (PTFD, PMFD and ROM) during flexion and return that might introduce confounding. The groups were then compared for differences in these variables.

RESULTS

There were significant segmental ROM differences among clusters in the database when PMFD and ROM were used as clustering variables, indicating heterogeneity. However, in the patient-control study, it was PTFD (velocity) that differentiated the groups. At L5-S1, this was at 10.82% of the motion path compared with 25.06% in the controls (p = 0.0002). For L4-5, PTFD was at 23.42% of the motion path in patients and 16.33% in controls (p = 0.0694) suggesting a reduced initial bending moment there. There were no significant differences for PMFD or ROM.

CONCLUSION

Peaking time of passive intervertebral velocity occurs early at L5-S1 in patients with CNSLBP; however, these findings should be treated with caution pending their replication. Future studies should explore relationships with altered disc pressures and biochemistry. Usefulness for monitoring regenerative disc therapies should be considered.

Associations between visceral fat chronic low back pain and central sensitization in patients with lumbar spinal stenosis

BACKGROUND

Pain sensitization may be one of the mechanisms contributing to chronic low back pain (CLBP).

OBJECTIVE

To evaluate the association between visceral fat, CLBP, and central sensitization (CS); describe the relationship between low back pain (LBP) intensity and CS; and identify possible correlation between visceral fat and LBP intensity.

METHODS

Patients with CLBP were divided using their CS inventory (CSI) scores into low- (CSI < 40) and high-CSI (CSI ⩾ 40) subgroups. We compared computed tomography (CT) measurements and scores for association with pain according to the visual analogue scale (VAS) between the two groups.

RESULTS

The low-CSI and the high-CSI groups had 47 patients (67.1%; 21 men, 26 women) and 23 patients (32.9%; 11 men and 12 women), respectively. The high-CSI group had a significantly higher mean VAS score (p< 0.01) and estimated mean visceral fat area (p< 0.05) than the low-CSI group. There was a moderate positive correlation between VAS score and visceral fat (standardised partial regression coefficient: 0.659, p< 0.01) in the high-CSI group according to multiple linear regression analysis adjusted for age and sex.

CONCLUSIONS

Visceral fat is associated with CLBP, regardless of sex or age, and may be a potential therapeutic target for CLBP with CS.

Factors associated with low back pain in patients with lumbar spinal stenosis: a cross-sectional study

BACKGROUND

Low back pain (LBP) is a major symptom of symptomatic lumbar spinal stenosis (SLSS). It is important to assess LBP in patients with SLSS to develop better treatment. This study aimed to analyse the factors associated with LBP in patients with SLSS.

METHODS

This cross-sectional study included consecutive patients with SLSS aged between 51 and 79 years who had symptoms in one or both the legs, with and without LBP. The participants were classified into two groups: the high group (LBP visual analogue scale [VAS] score ≥ 30 mm) and the low group (LBP VAS score < 30 mm). We performed multiple logistic regression analysis with the high and low groups as dependent variables, and a receiver operating characteristic (ROC) analysis.

RESULTS

A total of 80 patients with LSS were included (35 men and 45 women; mean age 64.5 years), with 47 and 30 patients in the high and low groups, respectively. Multivariate logistic regression analysis revealed that the sagittal vertical axis (SVA; + 10 mm; odds ratio, 1.331; 95% confidence interval, 1.051 - 1.660) and pelvic incidence-lumbar lordosis (PI-LL; + 1°; odds ratio, 1.065; 95% confidence interval, 1.019-1.168) were significantly associated with LBP. A receiver operating characteristic analysis revealed cut-off values of 47.0 mm of SVA and 30.5° of PI-LL, respectively.

CONCLUSION

Our results indicated that SVA and PI-LL were significant predictors for LBP in SLSS. It is suggested that these parameters should be taken into consideration when assessing LBP in patients with SLSS.

Imaging diagnosis for intervertebral disc

Various functional magnetic resonance imaging (MRI) techniques have been investigated in recent years and are being used in clinical practice for the patients with low back pain (LBP). MRI is an important modality for diagnosing intervertebral disc (IVD) degeneration. In recent years, there have been several reported attempts to use MRI T2 mapping and MRI T1ρ mapping to quantify lumbar disc degeneration. MRI T2 mapping involves digitizing water content, proteoglycan content, and collagen sequence breakdown as relaxation times (T2 values) at each site. These digitized values are used to create a map, that is, then used to quantitatively evaluate the metabolite concentrations within IVD tissues. MRI T2 mapping utilizes the T2 relaxation time to quantify moisture content and the collagen sequence breakdown. MRI T1ρ mapping digitizes water molecule dispersion within the cartilaginous matrix to evaluate the degree of cartilaginous degeneration. Magnetic resonance spectroscopy is a less-invasive diagnostic test that provides biochemical information. Adequate analysis of the IVD has not yet been performed, although there are indications of a relationship between the adipose content of the multifidus muscle in the low back and LBP. The ultra short TE technique has been recently used to investigate lumbar cartilaginous endplates. Unlike diagnosis based on contrast-enhanced images of the IVD, which depends on the recurrence of pain that is determined subjectively, MRI-based diagnosis is less-invasive and based on objective imaging findings. It is therefore expected to play a key role in the diagnostic imaging of IVD conditions in the future.

Evaluation of intervertebral disc using T2 mapping sequences in patients undergoing O2-O3 chemiodiscolysis: an instrumental study with clinical correlation

PURPOSE

To assess the MRI modifications of the intervertebral disc (IVD) treated by chemiodiscolysis using T2 mapping sequences.

METHODS

Thirty sciatica patients (17 males, 13 females, mean age 47.52 years) were enrolled for percutaneous CT-guided O₂-O₃ chemiodiscolysis treatment. As a control group, we enrolled 30 patients who were treated by CT-guided periradicular injections. All patients were submitted to clinical (using VAS and Oswestry Disability index (ODI)) and imaging studies to evaluate the intervertebral disc area (IDA) and T2 mapping values of the IVD before and at 1-month follow-up.

RESULTS

In the study group, pre-treatment IDA mean values were 20.47 ± 1.62 cm², with significant reduction at the follow-up (P < 0.05). Mean pre-treatment T2 relaxation time values were 38.80 ± 4.51 ms, 44.05 ± 0.91 ms, and 45.45 ± 14.11 ms for anterior annulus fibrosus, nucleus pulposus (NP), and posterior annulus fibrosus, respectively, with significant increase at the level of the NP (P < 0.05) at the follow-up. Mean pre-treatment ODI and VAS scores were 21.5 ± 10.6 and 8.5 ± 0.57, with significant improvement at the post-treatment follow-up (P < 0.05). In the control group, despite clinical improvement, we did not find significant IVA reduction nor significant T2 values change after treatment. Correlation analysis of T2 mapping relaxation time values showed significant correlation of NP T2 mapping value with both the reduction of IDA (0.81, P < 0.001) and the improvement of VAS and ODI scores (0.86, P < 0.001) at 1 month. In the control group, we did not find any statistically significant correlation.

CONCLUSIONS

T2 mapping may be a useful indicator to predict disc shrinkage and the clinical response to CT-guided O₂-O₃ injection.