Abbott Proclaim 3660 Clinician Manual page 34

In addition, three patients from this study had their stimulators repositioned due to pain at the
original location. Three patients had reoperations to adjust lead position; one patient required two
reoperations, one to have 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 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 implanted with a SCS system. In the
study, 27 of 41 (66%) patients had permanent implants. All patients were examined after 6
weeks. Pain measurements were assessed at 3-6 month intervals for the first year and annually
thereafter. The median long-term follow-up was 34 months. A total of 24 of 27 (89%) patients
reported greater than 50% reduction in pain. Since the majority of the patients were treated for
FBSS, this article supports the use of SCS for the treatment of FBSS.
In this study, one patient required a revision because of electrode fracture. One patient required
removal of the system due to local infection. One patient required replacement of the IPG due to
mechanical failure. Overall, 16 of 27 (59%) patients required a total of 36 repositioning
procedures.
A retrospective analysis by Hassenbusch SJ et al. 1995 included patients with chronic lower body
pain, predominately neuropathic pain and pain either midline lower back and/or unilateral or
bilateral leg pain treated over a 5-year period. The study was a comparison of SCS to spinal
infusion of opioids. For patients with radicular pain involving one leg with or without unilateral
buttock pain, a trial of SCS was recommended first. For patients with midline back pain and/or
bilateral leg pain, a trial of long-term spinal infusion was recommended first. If the patients failed
screening with either of these modalities, the other was then tested. If the treatment reduced the
pain by 50%, the systems were internalized. A retrospective analysis of patients with unilateral leg
and/or buttock pain treated initially with SCS and bilateral leg or mainly low back pain treated
initially with spinal infusions of opioids was then done.
In this study, 42 patients were screened; 26 (62%) patients received spinal stimulation; 16 (38%)
received opioids via a spinal infusion pump. A total of 5 patients did not receive adequate pain
relief with SCS; 3 (7%) of these patients underwent trial spinal infusions and had effective pain
relief. There were 4 (10%) patients that underwent a trial of spinal infusion of opioid but did not
receive adequate pain relief; these patients were not tested with SCS. Pain severity was rated
using a verbal digital pain scale: "On a scale of 0 to 10 where 0 is no pain and 10 is the worst
pain you could ever imagine, what is your pain now?" (Hassenbusch SJ et al. 1995) 16 of 26
patients (62%) had greater than 50% pain relief with SCS. A total of 2 of 16 (13%) patients had
greater than 50% pain relief with opioids. Mean follow-up was 2.1 ±0.3 years. This analysis
supports the use of SCS for intractable low back and leg pain.
In this study, 7 (17%) patients suffered complications after implantation of the device; 5 (12%)
patients required repositioning of catheter type electrodes and 2 patients required revision of the
stimulator generator.
Safety Evaluation
Sixteen studies were identified based on the detailed inclusion/exclusion criteria to demonstrate
the safety of the Genesis™ (IPG) neurostimulation system (all references in the bibliography were
used). The studies included a total of 1253 patients.
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