System Handbook

Safety Information
9
included the VAS, pain drawings, medication use, SIP (Sickness Impact Profile), isometric
lower extremity testing, and patient questionnaires. An intent-to-treat analysis was
performed. After patients had SCS for 24 months, leg pain, pain when walking, standing
pain, pain’s effect on overall lifestyle, and the total analog scale scores were significantly
improved from baseline. In this study, 25% of the implanted patients had greater than 50%
improvement in pain rating.
In addition, 3 patients from this study had their stimulators repositioned due to pain at the
original location. Three patients had reoperations to adjust lead position; 1 patient required 2
reoperations, 1 patient had the device removed due to infection and later to have a new
device implanted. A diabetic patient had skin problems which required device removal; a
new device was later implanted. Two patients had the device removed due to unsatisfactory
pain relief.
The prospective study performed by Villavicencio et al. 2000 included 41 patients with pain
of various etiologies. The majority of the patients, 24 (59%), had Failed Back Surgery
Syndrome (FBSS), 7 (17%) had Complex Regional Pain Syndrome (CRPS I and II), 4
(10%) had neuropathic pain syndrome, and 6 (15%) were diagnosed as stroke or other.
Patients underwent an initial trial period for SCS with temporary leads. If the trial resulted
in greater than 50% reduction in the patient’s pain, as measured by the VAS, the patient was