European experience with bilateral sacral neuromodulation in patients with chronic lower urinary tract dysfunction.

Although there is experimental and clinical evidence that bilateral stimulation of the sacral nerves could lead to summation effects, no significant differences in unilateral versus bilateral neuromodulation could be demonstrated in a comparative trial. In some individuals, however, only bilateral stimulation relieved symptoms. Therefore, if a unilateral percutaneous nerve evaluation test fails, a bilateral test should be considered. Further clinical research with long-term follow-up will allow the identification of which patients could benefit from bilateral stimulation with greater specificity and ameliorate further the long-term results achieved with unilateral SNS.