Abstract - AAPM - The American Academy of Pain Management

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					Durrer A, Perruchoud C, Buchser E, et al.
Subcutaneous field stimulation for refractory low back pain
International Association for the Study of Pain. 13th World Congress on Pain (Montreal,
Canada – 08/29/2010 – 09/02/2010)
Background: The aim was to report on a series of consecutive patients with refractory low-
back pain treated with subcutaneous peripheral nerve stimulation. Spinal cord stimulation
(SCS) induced paraesthesia can often be elicited in the legs, however the lower back has
proven to be a much more difficult target. Derived from the experience with peripheral
nerve stimulation for the treatment of occipital neuralgia, we used subcutaneous nerve
stimulation in patients with low-back pain in whom paraesthesia could not be elicited in the
area of pain with SCS or declined the placement of an epidural lead.
Methods: Standard SCS lead and generator (Pisces Quad and Itrel 3, Medtronic Inc.,
Minneapolis USA) were used. The lead was inserted percutaneously using a Tuohy needle
that was advanced laterally from the midline in the subcutaneous tissue of the lower back.
Paraesthesia covering at least 80% of the painful area could be elicited in all patients. A
definitive generator was implanted after a 3-week test phase if the pain improved by at least
50%. Pain was measured by a 100 mm visual analogue scale (VAS) and analyzed with the
Dunnett’s test.
Results: 20 patients (10 females and 10 males, mean age: 54 years-old) were included.
Since this is an ongoing study, follow-up is available for 20, 17, 18, 16, 16 and 12 patients
at 1, 3, 6, 12, 24 and 36 months respectively. At 36 months, four were explanted (three due
to lack of efficacy and one to allow spine surgery) and four were lost at follow-up. The
mean VAS decreased significantly compared to baseline (61 mm ± 22) at 1 (28 mm ± 26;
p= 0.002), 3 (32 mm ± 29; p=0.01) and 6 months (32 mm ± 32; p=0.02) after the implant.
The mean decrease in VAS observed at 12 (39 mm ± 32), 24 (37 mm ± 30) and 36 months
(42 mm ± 28) is not statistically significant. The subjective improvement was 61%, 60%,
60%, 60%, 61% and 53% at 1, 3, 6, 12, 24 and 36 months respectively. Three patients
required electrode revision because of a fracture.
Discussion: Lumbar subcutaneous peripheral nerve stimulation is a simple and safe
alternative to epidural SCS that can be effective in the treatment of low back pain. It might
be considered when SCS either fails to elicit appropriate paraesthesia or cannot be used.
Statistical significance is lost after 12 months though a trend towards improvement persists.
The subjective improvement remains higher than 50% at 36 months.
Author Affiliation: Dept. of Anesthesiology and Pain Management, Ctr. for
Neuromodulation, Hosp. of Morges, Morges, Switzerland and Dept. of Anesthesiology,
Clinique de Valère, Sion, Switzerland

				
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posted:7/3/2011
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