Evolving patterns of spinal cord stimulation in patients implanted for intractable low back and leg pain.

The authors noted that an SCS screening trial would be considered successful if the patient reported a 5% reduction in pain. We believe it is safe to assume that this is a typographical error and that the authors required the usual 50% reduction.

Publication Information

Author(s): Sharan A, Cameron T, Barolat G.
Journal: Neuromodulation
Volume, issue, pages: 5(3):167-179
Year: 2002
Full Text Link:
PubMed Link: http://www.ncbi.nlm.nih.gov/pubmed/22150814

Study description

Study design: Prospective multicenter
Study question: What SCS strategies are used to program two-columns of contacts to treat low back pain?
Population assessed: Human. Implanted (subset of those enrolled in previously reported trial).
Follow-up intervals: Postop (16 pts), 6 (21 pts), 12 (20 pts), 24 (10 pts) mos.
Patient protection: Informed consent
Outcome measures: VAS (but they refer to 10-point VAS scores, which would be an NRS instead); pain relief 0 to 5 scale; programming parameters; pain/paresthesia overlap recorded on anatomic maps and graded 1 (100%), 2 (50-99%), or 3 (<50%) at each FU, with low back coverage graded 0 = none to 3 = entire
Definition of success: Pain relief 2 (deemed fair)
Statistical significance: 2-tailed P < 0.05
Statistical analyses performed: Wilcoxon signed rank test (Statistica 6.0)

Patient selection

Inclusion criteria: Pain duration at least 1 year, failed conventional treatment, all had 'surgical intervention on the lumbar spine,' but FBSS only considered the primary diagnosis in 15, unclear if this was inclusion criterion
Pre-op diagnostic imaging: Required
Organic pain origin required: Evidence of lumbar pathology

Demographic / prognostic factors

Sex (male/female): Previous report referenced for demographics

Pain location

Back only or predominant: 26 (at least 50% back pain)
Leg(s): 26
Unilateral: 9
Bilateral: 17

Pain characteristics

Pain duration years (mean +/- SD, range): At least 1

Indications (trial/implant)

Failed back surgery syndrome: 15 (primary diagnosis)
Radiculopathy: 6
Arachnoiditis: 5

Screening trial

Trial success criteria: 'The trial was considered successful when a patient reported at least a 5 [sic] percent reduction in pain.' (The authors undoubtedly meant 50%.)
Trial duration (days): On table or extended

Stimulation

Paresthesia coverage: Grade 1 = 67% postop, 44% 6 mos, 69% 12 mos, 57% 24 mos
Stimulation programming methods: 53% active contacts on both columns postop increased to 74% at 24 mos.
Parameters: 88% cathode locations changed (most from upper half of T9 to bottom of T9-top of T10) during FU; pulse stable over FU; frequency decreased from mean 93.5 +/- 63.6 Hz at 6 mos to 48.3 +/- 50 at 24 mos; amplitude increased from 4.3 +/- 2.0 at 6 mos to 7.1 +/- 2.0 at 24 mos; significantly more contacts were programmed as anodes vs. cathodes at each FU, and active contacts n= 4.1 +/- 1.6 at postop and 6.4 +/-2.4 at 24 mos

System implantation

Number implanted: 26
Type(s) of implanted electrode(s): 16-contact paddle Lamitrode 88 or two parallel perc Lamitrode 8's
Manufacturer: Advanced Neuromodulation Systems
Electrode implantaton method: Laminotomy technique
Electrode location(s): T7 to T10
Type of IPG: RF (MNR 916 series)
Location of IPG: Individualized

Outcomes

Number in study: 26
Number followed: Varied according to time: (10 = 24 months; 20 = 12 months; 21 = 6 months; 16 = immediate postop only)
Answer to study question: See results (descriptive rather than dichotomous answer)
Rate of success if defined: 83% at 6 mos; 94% at 12 mos; 75% at 24 mos
Outcomes reported as function of time?: Yes
Outcomes broken down by indication?: Yes

Outcomes: pain

Good overall relief: 30% reduced pain score at 6 mos; 37% at 12 mos; 30% at 24 mos; all patients reduced pain score

Other beneficial outcomes

Biological complications

Device complications

Stimulation side effects

Cost effectiveness

Faculty and staff

Facility location: USA
Facility type: University hospital

Data extraction information