Practice Parameters for the Use of Spinal Cord Stimulation in the Treatment of Chronic Neuropathic Pain

Trial Length

Does the length of a screening trial affect its ability to provide valid information, and what is the optimum length?

Valid information about pain/paresthesia coverage and pain relief can be obtained soon after the trial begins.  Gaining valid information about the patient's degree of acceptance of the therapy, however, requires more time as does gathering information that supports the patient's report of pain relief (an appropriate reduction in medication consumption and increase in physical activity).

A trial of three to eight days generally provides sufficient information yet is short enough to reduce the likelihood of infection.  Some practitioners, however, conduct trials of up to 3 weeks in duration.  Others, in some circumstances, conduct an "on-table" trial and implant the SCS system immediately after testing.

The advantage of on-table testing is that it obviates the need for a second procedure.  The disadvantage is that the abbreviated trial could fail to provide information adequate to predict a short-term failure, which would require a second procedure to reverse the unwarranted implantation of the system.

(Reminder:  This information applies to patients with neuropathic, not ischemic pain.  In the latter case, clinical practice might differ.)

Strength of recommendation Evidence source(s)/rationale
B = Recommended
Uncertain validity, apparently useful
  • Weighing risk versus potential benefit and expert consensus reveals a good likelihood of a favorable outcome 

Weinand ME, Madhusudan H, Davis B, Melgar M. Acute vs. prolonged screening for spinal cord stimulation in chronic pain. Neuromodulation 6(1):15-19, 2003.
Abstract | Wikistim Entry

North RB. SCS trial duration [editorial]. Neuromodulation 6:4-5, 2003.