Introduction

Failed back surgery syndrome (FBSS) is a challenging condition lacking curative treatment. Neuropathic pain medication is recommended as a first line treatment. Spinal cord stimulation (SCS)[1] has proven to be effective in selected patients refractory to medication [2].

Methods/Materials

Study group consists of all 211 patients who underwent SCS trial with a surgical lead between January 1, 1997 and March 31, 2014 in a single tertiary center. For each patient, 3 matched controls were selected.

All purchases of prescribed neuropathic pain medication and opioids between January 1, 1995, and March 31, 2016, and their daily defined doses (DDD) were retrieved from nationwide registries. Continuous use was defined as two or more purchases during six months before SCS implantation.

Patients were divided into three groups: 1) SCS trial only, 2) successful SCS, and 3) unsuccessful SCS, defined as explantation or revision due to inadequate pain relief. We analyzed neuropathic pain medication and opioid use during a period starting two years before SCS and ending two years after SCS implantation.

Results

After the one-week trial, permanent SCS was implanted in 164 (78%) patients. Of them 72 (43%) used neuropathic pain medication compared to 18 (38%) in trial group. Of 135 patients with successful SCS, 62 (46%) used neuropathic pain medication as compared to 10 of 29 patients (34%) with unsuccessful SCS.

Mean DDD increased in all groups until implantation, but then it levelled off. Patients used neuropathic medication significantly more than controls (Table 1). Strong opioid use increased neuropathic medication dose significantly (Figure 1).

Table 1. Neuropathic pain medication in DDD (mean±SD) ( *p<0.001).

Discussion

This is a retrospective study with all consecutive patients treated with SCS during the study period in our hospital. Neuropathic pain medication is likely to increase until interventional pain procedures. With successful SCS patients seem to be more able to reduce neuropathic pain medication. With all treatment groups, a strong opioid indicates an increase in neuropathic pain medication.

Conclusions

SCS patients with FBSS use more neuropathic pain medication than controls. Neuropathic pain medication can be stabilized or reduced with successful SCS. Neuropathic pain medication is almost doubled with combined strong opioid.

References

[1]

Maher DP, Martins YC.Neuropathic Pain Medication Use Does Not Alter Outcomes of Spinal Cord Stimulation for Lower Extremity Pain. 2018;21:106–113.

[2]

North RB, Kidd DH. Spinal cord stimulation versus repeated lumbosacral spine surgery for chronic pain: a randomized, controlled trial. 2005;56:98–106.