User's Manual

Information for Prescribers

Precision Spectra™ System Information for Prescribers

90668515-01 Rev A 2 of 15

The prospective study by Ohnmeiss et al. 1996, examined the long-term effectiveness of SCS

in patients with intractable leg pain. Forty patients were implanted with SCS systems and

evaluated at 6 weeks, 12 months, and 24 months follow-up. Outcome measures included the

VAS, pain drawings, medication use, SIP (Sickness Impact Proﬁ le), 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 signiﬁ cantly 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 implanted with

a SCS system. In this study, 27/41 patients, 66%, had permanent implants. All patients were

examined after 6 weeks. Pain measurements were assessed at 3-6 month intervals for the

ﬁ rst year and annually thereafter. The median long-term follow-up was 34 months. A total

of 24/27 (89%), 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 performed 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 ﬁ rst. For patients with midline

back pain and /or bilateral leg pain, a trial of long-term spinal infusion was recommended ﬁ rst.

If the patients failed screening with either of these modalities, the other was then tested. If the