Clinical Research| Volume 22, ISSUE 6, P709-715, August 2019

Download started.


Needle Placement and Position of Electrical Stimulation Inside Sacral Foramen Determines Pelvic Floor Electromyographic Response—Implications for Sacral Neuromodulation


      Lead placement within the sacral foramen in sacral neuromodulation patients is guided by visual assessment of the contraction of the pelvic floor musculature (PFM) and/or verbal assessment of the sensation and location of sensation upon stimulation. Generally, lead placement is proceeded by needle probing. This study evaluates which location inside a single sacral foramen would be most ideal for the release of the permanent electrode lead, by measuring electromyographic (EMG) motor responses of the PFM upon stimulation of a peripheral nerve evaluation (PNE) needle.

      Materials and Methods

      In eight patients, four standard PNE needles, and in one patient, two PNE needles, were introduced into the same foramen, parallel to the midline and parallel to each other. Position was verified by X-ray. Needles were stimulated (square pulsed waves, 210 μsec, 14 Hz) at increasing amplitudes (1-2-3-5-7-10 mA). PFM EMG was measured using the Multiple Array Probe (MAPLe) placed intravaginally or intrarectally, with 24 derivations. For this study, the mean (normalized) EMG was taken of all electrodes and different positions within the foramen were compared using the Wilcoxon signed rank test.


      A total of 202 PFM EMG measurements were recorded upon stimulation. EMG motor responses of the PFM for current stimulation = <2 mA showed statistically significant higher mean (normalized) EMG values for needles positioned cranial, medial, and cranial-medial, in comparison to needles positioned caudal, lateral, and caudal-lateral (p = 0.004; p = 0.021; p = 0.002).


      Our data suggest stronger PFM contractions are elicit in cranial- and medial-placed PNE needles upon stimulation with clinically relevant current amplitudes (≤ 2 mA). Placement of the lead should aim for this spot in the foramen.


      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Tutolo M
        • Ammirati E
        • Heesakkers J
        • et al.
        Efficacy and safety of sacral and percutaneous Tibial neuromodulation in non-neurogenic lower urinary tract dysfunction and chronic pelvic pain: a systematic review of the literature.
        Eur Urol. 2018; 73: 406-418
        • Amend B
        • Matzel KE
        • Abrams P
        • de Groat WC
        • Sievert KD.
        How does neuromodulation work.
        NeurourolUrodyn. 2011; 30: 762-765
        • Amend B
        • Khalil M
        • Kessler TM
        • Sievert KD.
        How does sacral modulation work best? Placement and programming techniques to maximize efficacy.
        Curr Urol Rep. 2011; 12: 327-335
        • Matzel KE
        • Chartier-Kastler E
        • Knowles CH
        • et al.
        Sacral neuromodulation: Standardized electrode placement technique.
        Neuromodulation : J Int Neuromod Soc. 2017; 20: 816-824
        • McLennan MT.
        The role of electrodiagnostic techniques in the reprogramming of patients with a delayed suboptimal response to sacral nerve stimulation.
        Int Urogynecol J Pelvic Floor Dysfunct. 2003; 14: 98-103
        • Matzel KEC-KE
        • Knowles CH
        • Lehur PA
        • et al.
        Sacral neuromodulation: standardized electrode placement technique.
        Neuromodulation. 2017; 20: 816-824
        • Voorham-van der Zalm PJ
        • Voorham JC
        • van den Bos TW
        • et al.
        Reliability and differentiation of pelvic floor muscle electromyography measurements in healthy volunteers using a new device: the multiple Array probe Leiden (MAPLe).
        NeurourolUrodyn. 2013; 32: 341-348
        • Schmidt RA
        • Senn E
        • Tanagho EA.
        Functional evaluation of sacral nerve root integrity. Report of a technique.
        Urology. 1990; 35: 388-392
        • Xu R
        • Ebraheim NA
        • Robke J
        • Huntoon M
        • Yeasting RA.
        Radiologic and anatomic evaluation of the anterior sacral foramens and nerve grooves.
        Spine (Phila Pa 1976). 1996; 21: 407-410
        • Buchs NC
        • Dembe JC
        • Robert-Yap J
        • Roche B
        • Fasel J.
        Optimizing electrode implantation in sacral nerve stimulation—an anatomical cadaver study controlled by a laparoscopic camera.
        Int J Colorectal Dis. 2008; 23: 85-91
        • Swinn MJ
        • Schott GD
        • Oliver SE
        • Kitchen ND
        • Fowler CJ.
        Leg pain after sacral neuromodulation: anatomical considerations.
        BJU Int. 1999; 84: 1113-1115
        • Siegel SW
        • Catanzaro F
        • Dijkema HE
        • et al.
        Long-term results of a multicenter study on sacral nerve stimulation for treatment of urinary urge incontinence, urgency-frequency, and retention.
        Urology. 2000; 56: 87-91
        • Cohen BL
        • Tunuguntla HS
        • Gousse A.
        Predictors of success for first stage neuromodulation: motor versus sensory response.
        J Urol. 2006; 175 (discussion 2180-2171.): 2178-2180
        • Goldman HB
        • Lloyd JC
        • Noblett KL
        • et al.
        International continence society best practice statement for use of sacral neuromodulation.
        NeurourolUrodyn. 2018; 37: 1823-1848