Analysis of Somatosensory Profiles Using Quantitative Sensory Testing During Tonic and BurstDR Stimulation for the Treatment of Chronic Pain.

BACKGROUND

In the presence of neuropathic pain, other sensory qualities, such as touch or pressure, which are a sign of nerve damage, are almost always affected. However, it is unclear to which extent spinal cord stimulation (SCS) influences these simultaneously damaged sensory pathways or possibly contributes to their regeneration.

OBJECTIVES

The aim of this study was to investigate the effects and possible differences of tonic and BurstDR (Abbott, Austin, TX) SCS on somatosensory profiles of patients with chronic neuropathic pain, using quantitative sensory testing (QST).

STUDY DESIGN

A randomized, single-blinded, single-center study.

SETTING

University medical center.

METHODS

After a washout phase of 4 hours and having done the basic QST measurement, either tonic or BurstDR stimulation was performed for 30 minutes in a randomized fashion. Then, the second measurement was taken. The third measurement followed after using the remaining stimulation mode for 30 minutes. Mean values of all QST parameters were calculated and compared. We also computed Z-values using standard data.

RESULTS

We examined 14 patients (9 women, 5 men, mean age 58.4 years) with previously implanted SCS systems for chronic neuropathic pain, using QST (7 tests, 13 parameters).The QST raw data showed a statistically significant improved vibration sensation (A-Beta) (P = 0.019) and lower mechanical pain threshold (A-Delta) (P = 0,031) when testing BurstDR in comparison to tonic SCS. We found a significant improvement in the vibration sensation and also A-Beta fiber function during BurstDR when we used the Z-value analysis (P = 0.023). With regard to Z-values, BurstDR seemed to be superior regarding the normalization tendency of the A-Delta fiber function in the mechanical pain threshold (P = 0.082), and tonic SCS seemed superior regarding heat detection threshold (C) and cold pain threshold (C and A-Delta) (P = 0.093).

LIMITATIONS

The study is limited by its small number of cases.

CONCLUSIONS

In this study, it could be shown that, in some QST parameters and tested fiber functions, normalization tendencies were recognizable by using BurstDR or tonic SCS. However, BurstDR SCS seemed to be superior to tonic stimulation in this regard.