Effect of Spinal Cord Stimulation on Pain Thresholds and Sensory Perception in Chronic Pain Patients (SCS)
The purpose of this study is to better understand how the Spinal Cord Stimulator works in relieving chronic pain.
The investigators are asking subject to take part in this study because who are chronic pain patients who already have a Spinal Cord Stimulator (SCS) in place.
The investigators hypothesize that chronic pain patients will have higher heat pain threshold, heat pain tolerance and wind-up over the painful areas with the SCS on.
QST (Quantitative Sensory Testing, a heat/cold simulation test) might be an objective helpful tool for prudent patient selection for an expensive and invasive procedure for future SCS placement.
|Study Design:||Observational Model: Case-Only
Time Perspective: Cross-Sectional
|Official Title:||Effect of Spinal Cord Stimulation on Pain Thresholds and Sensory Perception in Chronic Pain Patients|
- Quantitative Sensory Testing [ Time Frame: 1 Visit ] [ Designated as safety issue: No ]
|Study Start Date:||June 2010|
|Estimated Study Completion Date:||June 2015|
|Estimated Primary Completion Date:||June 2014 (Final data collection date for primary outcome measure)|
Sixty subjects who already have an implanted SCS device for pain management at the MGH Center for Pain Medicine and other Partners affiliated pain centers will be enrolled.
- Subject is 18 years or older.
- Subject has an SCS device implanted for at least one month for pain control. This requirement is set to ensure that the subject becomes familiarized with the therapy and has recovered from the surgical implantation of the SCS device.
- Subject has neurological disease or a condition causing sensory deficit to the painful area.
- Subject had recent therapy that may influence QST results, e.g., neuroablative procedure within two-months.
- Subjects who are unable to travel to the study center.
It will be a one time outpatient visit study, which will include the following:
Brief pain history and Neurological examination
- Medical History (including medication use);
- Pain location, intensity, character and if known, etiology, duration;
- Maps of pain locations and paresthesia locations;
- Sensory neurological examination (e.g., alcohol swab, cotton swab, pinprick and vibration);
- A check on routine vital signs (blood pressure, pulse, pulse oximetry).
QST will include the following:
- Warm sensation, heat pain threshold, heat pain tolerance and wind-up. A cut-off of 53°C for heat will be preset to avoid tissue damage.
- QST will be done on three areas; painful area, non-painful area with paresthesia and non-painful area without paresthesia with the SCS turned off.
- Subject will then turn on SCS and a repeat QST will be performed on the three above mentioned areas.
- QST tests will be performed in a quiet room at temperature 25º 2° C. The time and duration of the QST tests will be recorded.
QST will be performed at least 4 hours and no later than 6 hours after the last dose of long acting opioid and after last SCS on time. In this way the investigators will try to avoid recording possible end dose withdrawal and provide sufficient time for the subject to return to baseline for their SCS therapy.