Treatment of failed back surgery syndrome patients with low back and leg pain: a pilot study of a new dual lead spinal cord stimulation system.

Dr. Van Buyten informs us that the data presented here and in the Results section of his paper are correct. The numbers differ from the data that appear in the Discussion section of the paper due to transcription errors.

Publication Information

Author(s): van Buyten J-P, van Zundert JV, Milbouw G.
Journal: Neuromodulation
Volume, issue, pages: 2(4):258-265
Year: 1999
Full Text Link:
PubMed Link:

Study description

Study design: Retrospective (pilot) dual-center study
Study question: What clinical benefits do patients gain from SCS with dual electrodes?
Population assessed: Human. Implanted.
Study dates: Implanted Aug 23, 1995 to Feb 5, 1997; then followed.
Follow-up duration: 2 years
Follow-up intervals: Interim at mean 9 months (2 to 20) and then mean 28 months (20 to 38)
Outcome measures: Questionnaire, interviews, 0 to 10 VAS
Secondary outcomes: Back surgery history; global, leg, back pain; medication use; sleep; activities; work; 'SCS system hardware inconveniences'; willingness to repeat
Statistical significance: P = < 0.05
Statistical analyses performed: SAS software: paired t-test for continuous variables (mean, # observations, SD, range); McNemar's test for categorical data (%, # observations)

Patient selection

Inclusion criteria: Consecutive SCS candidates in whom it would be difficult to cover the low back with paresthesia

Demographic / prognostic factors

Sex (male/female): 6 male; 14 female offered enrollment; 5 male; 12 female participated
Mean patient age in years (+/- SD, range): 47 (32 to 61) (for 20 offered enrollment)
Number prior surgeries difference in outcome: (Number and type are tabulated but not related to results)
Issues of secondary gain: Those not working 'were supported by health insurance compensation'

Pain location

Back and leg(s): 17
Other location: 3 had 'pain above the waist'
Unilateral: 9
Bilateral: 8

Pain characteristics

Pain duration years (mean +/- SD, range): 'Long history'
Neuropathic: 17 leg pain

Indications (trial/implant)

Failed back surgery syndrome: 17

Screening trial

Number patients who underwent trial: 17 (19 or 20 must have had trial because 2 were dropped from study when SCS was removed, and 1 refused to participate)
Trial electrode type: Two percutaneous quadripolar electrodes
Trial electrode manufacturer: Medtronic
Trial technique: Electrode tips side-by-side or staggered
Trial success criteria: 'Successful' trial, but 'Obtaining at least 50% pain relief in both the legs and back. . .was waived as an absolute criterion. . ..'
Length of hospitalization: 1 week
Trial duration (days): 1 month


Paresthesia coverage: 86.5% overall; 83.3% in 12 whose LBP > leg pain (electrode tip at T7 to T10); 94% in 5 whose leg pain > LBP (tip at T10 to T12)
Stimulation programming methods: Patients could adjust amplitude; otherwise width (450 microsec) and rate (85 pp) only adjusted in cases of unpleasant paresthesia
Parameters: Dual channel = alternating between one electrode and the other; means and range for each parameter per each electrode are tabulated

System implantation

Number implanted: 17
Type(s) of implanted electrode(s): Two percutaneous quadripolar electrodes (screening trial electrodes or de novo?)
Manufacturer: Medtronic
Electrode implantaton method: 9 placed side-by-side; 8 staggered
Electrode location(s): T7 to T10 at one medical center; T10 to T12 at the other
Type of IPG: Mattrix radiofrequency


Number in study: 20
Number followed: 17
Number lost to follow-up: 3
Number died: 0
Answer to study question: These preliminary findings indicate that SCS with dual electrodes is beneficial to FBSS patients with chronic low back and leg pain.

Outcomes: pain

Mean pain reduction: 4.4 (0.2 to 9.9) P < 0.001
Pain reduced back: 4.2 (0.5 to 9.8) P < 0.001
Pain reduced legs: 4.9 (1.2 to 9.8) P < 0.001
Reduced analgesics: Among non-narcotics, 13 reduced or eliminated analgesics (56% had >50% reduction); among narcotics 8 of 14 discontinued use

Other beneficial outcomes

Change in activities of daily life: 10 increased ability; 2 decreased; 5 no change
Change in sleep: Sleep patterns improved but not significantly; use of sleep medication was stable
Patient satisfaction or impression of change: 14 would repeat, 2 were uncertain, 1 would not
Return to work: 4 stopped working for other reasons after SCS implant; 3 were working at interim FU; 2 continued to work

Biological complications

Other biological complication: 'Possible severe arachnoiditis' in one pt not counted in FU data

Device complications

Other hardware failure: One electrode removed during spine surgery (reason not given); patients found external equipment uncomfortable

Stimulation side effects

Uncomfortable stimulation: 'Aberrant' in one patient not counted in FU data

Cost effectiveness

Faculty and staff

Facility location: Belgium
Facility type: Hospitals

Data extraction information