Short-Term Effect of Lumbar Traction on Intervertebral Discs in Patients with Low Back Pain: Correlation between the T2 Value and ODI/VAS Score

Abstract

Objective: The effect of lumbar traction on low back pain (LBP) patients is controversial. Our study aims to assess changes in the intervertebral disc water content after lumbar traction using T2 mapping and explore the correlation between changes in the T2 value and Oswestry Disability Index (ODI)/visual analogue scale (VAS) score.

Design: Lumbar spine magnetic resonance imaging was performed, and the ODI/VAS scores were recorded in all 48 patients. Midsagittal T2-weighted imaging and T2 mapping were performed to determine the Pfirrmann grade and T2 value. Then, the T2 values were compared between pre- and posttraction, and the correlation between changes in the T2 value and ODI/VAS scores were examined.

Results: In the traction group, the changes in the nucleus pulposus (NP) T2 values for Pfirrmann grades II-IV and the annulus fibrosus (AF) T2 values for Pfirrmann grade II were statistically significant after traction (P < 0.05). Changes in the mean NP T2 value of 5 discs in each patient and in the ODI/VAS score showed a strong correlation (r = 0.822, r = 0.793).

Conclusion: T2 mapping can be used to evaluate changes in the intervertebral disc water content. Ten sessions of traction resulted in a significant increase in quantitative T2 measurements of the NP in discs for Pfirrmann grade II-IV degeneration and remission of the patients' clinical symptoms in the following 6 months. Changes in the mean NP T2 value of 5 discs in each patient were strongly correlated with changes in the ODI/VAS score.

Keywords: ODI/VAS score; T2 mapping; intervertebral disc; low back pain; lumbar traction.

Figure 1.

Female, 35 years old, complaining of low back pain lasting for 8 months. (a) Sagittal T2 weighted image (T2WI) showing that the L3/L4 disc is classified as Pfirrmann grade II and the L4/L5 disc is classified as Pfirrmann grade III. (b) T2 mapping pretraction. (c) T2 mapping posttraction. Images b and c show that the nucleus pulposus (NP) T2 value increased visually after traction (from 128.4 to 150.3 in the L3/L4 disc and from 79.1 to 92.4 in the L4/L5 disc) but that the annulus fibrosus (AF) T2 value did not obviously change (from 46.3 to 45.8 in the L3/L4 disc and from 45.5 to 44.8 in the L4/L5 disc).

Figure 2.

Male, 47 years old, complaining of low back pain lasting for 1.5 years. (a) Sagittal T2 weighted image (T2WI) showing that the L4/L5 disc is classified as Pfirrmann grade IV. (b) T2 mapping pretraction. (c) T2 mapping posttraction. Images b and c show that the nucleus pulposus (NP) T2 value increased after traction (from 48.4 to 54.6) but that the annulus fibrosus (AF) T2 value showed no obvious change (from 38.6 to 38.3).

Figure 3.

Female, 39 years old, complaining of low back pain lasting for 3 years. (a) Sagittal T2 weighted image (T2WI) showing that the L2/L3 disc is classified as Pfirrmann grade II, the L4/L5 disc as Pfirrmann grade III, and the L5/S1 disc as Pfirrmann grade IV. (b) T2 mapping preintervention. (c) T2 mapping postintervention. Images b and c show no obvious changes in the nucleus pulposus (NP) T2 value for the Pfirrmann grade II to IV discs (from 126.3 to 126.1 for Pfirrmann grade II, from 77.1 to 77.6 for Pfirrmann grade III, and from 50.5 to 46.6 for Pfirrmann grade IV) or the annulus fibrosus (AF) T2 value for Pfirrmann grades II to IV (from 46.7 to 47.5 for Pfirrmann grade II, from 49.2 to 48.2 for Pfirrmann grade III, and from 43.6 to 43.8 for Pfirrmann grade IV).

Figure 4.

In the traction group, the mean nucleus pulposus (NP) T2 value for Pfirrmann grades II to IV significantly increased from pre- to posttraction (P < 0.05).

Figure 5.

In the traction group, the mean anulus fibrosus (AF) T2 value for Pfirrmann grade II significantly increased from pre- to posttraction (P < 0.05). Otherwise, changes in the mean AF T2 value for Pfirrmann grades III and IV from pre- to posttraction were not statistically significant (P > 0.05).