Introduction

Multiple Sclerosis (MS) is a chronic disease with autoimmune etiology affecting the brain and spinal cord, characterized by several functional limitations. Pain is a common experience by up to 75% of patients, and this is the symptom with more impact on quality of life. Spinal cord stimulation (SCS) is a minimally invasive technique mainly indicated for neuropathic pain. The literature indicates  that SCS may be an effective option for refractory neuropathic pain associated with MS.  The efficacy of SCS, such as other treatment in the pain management, is considered positive if it is related to a reduction of pain, despite the most recent definition of pain that considers several aspects characterizing this unpleasant experience for the patient.

Methods

We report a case of a 38 years old patient with diagnosed primary progressive MS (PPMS).
The patient presented neuropathic bilateral lower limb pain described as constrictive and burning, functional limitations including gait abnormalities, and sensory disturbances in the lower extremities. The pain was intractable with high dosage of gabapentinoids, opioids and cannabinoids.
We discussed with the patient about the possibility of SCS for pain. He was willing to try the treatment.
We planned to place a High Frequency MRI-Compatible Spinal Cord Stimulator in two stages to let the patient experience the neurostimulation for the trial phase and decide whether to continue with the implanted pulse generator (IPG) placement. We placed two peridural leads with the tip positioned at T7 and T9 level, with intraoperative paresthesia mapping that was overlapping the region of pain. After four weeks of trial, the patient reported only minimal change in pain, but an important satisfaction on quality of life, therefore we decided for the placement of the IPG. The programs used were: HF (10 kHz, 30 msec pulse width, 2.5 mA) and a combined program of HF and low frequency (2 Hz, 440 msec pulse width, 5-10 mA) stimulation, with the target area at T9 and T11.
We followed up the patient regularly until 12 months collecting Numeric Rate Scale (NRS), Brief Pain Inventory for pain (BPI pain) and quality of life (BPI qol), Oswestry Disability Index (ODI) and DN4 test.

Results

Table 1 reports the measures at baseline (T0), end of trial (T1), 1- (T2), 6- (T3) and 12-months (T4) follow-ups, showing the non-significant changes of NRS, ODI and DN4 but improvement of BPI.

Conclusions

Pain is often associated with MS, contributing to a decreased quality of life.
We have presented a clinical case of a patient treated with SCS for intractable neuropathic pain with follow-up at 12 months.
The non-significant changes in ODI and DN4 could be explained with the disability and neurologic alterations characterizing the MS. Despite the non-relevant influence on NRS measures and ODI, the impact of the neurostimulation on the quality of life has been positive and it is still maintained at 12-months follow-up.
The most recent definition of pain considers several aspects characterizing the unpleasant experience for the patient. For this reason, observing the improvement in quality of life after the trial period we decided to maintain the SCS.
The improvement of quality of life should be relevant for therapeutic decision making in pain medicine.