The use of a sensory passport on different parameter settings during the sacral neuromodulation procedure

Van de Borne S1, Vaganée D1, Vermandel A1, De Wachter S G1

Research Type

Clinical

Abstract Category

Neurourology

Abstract 509
Open Discussion ePosters
Scientific Open Discussion Session 28
Friday 31st August 2018
12:50 - 12:55 (ePoster Station 2)
Exhibition Hall
Pelvic Floor Neuromodulation Prospective Study New Instrumentation
1. Department of Urology, Antwerp University Hospital, Edegem, Belgium
Presenter
D

Donald Vaganée

Links

Poster

Abstract

Hypothesis / aims of study
Sacral neuromodulation is a longstanding treatment for patients with overactive bladder (OAB) or non-obstructive urinary retention (NOUR), refractory to conservative treatments. A tined lead with 4 electrodes is placed through the third or fourth sacral foramen. Which electrode settings are used for the therapeutic response is usually defined based upon the sensory response on stimulation. Perianal or genital sensation on stimulation are considered optimal sites for response. Currently, patients are asked to say where they feel the stimulation, but clinical experience shows that this is not always easy for the patients, questioning the reliability of its use. Therefore a dermatome chart with coordinates was developed where patients can show with their finger the place of sensation. This study evaluates if the sensory responses upon stimulation of the different electrode configuration is repeatable and reliable using the dermatome chart.
Study design, materials and methods
Single tertiary center, prospective study (December 2017 - March 2018) including 18 patients with OAB or NOUR.
To map the sensory responses a pelvic dermatome chart was developed with 1cm² squares with coordinates. The following electrode settings were tested: 0-3+/1-3+/2-3+/3-0+/3-1+. Square wave pulses with pulse width of 210µsec and 14Hz frequency were delivered at the respective electrodes with increasing amplitudes up to the sensory threshold (ST). The amplitude was noted as well as the point that the patient marked on the dermatome chart. Based upon the point marked by the patient 3 locations were defined: “perianal”, “genital” and “other” (leg, toe, lower back). This procedure was done twice with 10 minutes interval. For the ST test-retest reliability was assessed using the Pearson correlation coefficient and displayed using a Bland Altman and correlation plot.
For the perceived location of sensation (PLoS) test-retest reliability was assessed using Cohen’s kappa coefficient.
Results
18 consecutive patients referred for sacral neuromodulation were included in this study. 
Age: 57,3 +/- 14,9 (range 38-83) years. Gender: 16 (89%) females, 2 (11%) males. Indications: OAB: 16 (89%), NOUR: 2 (11%). 
All patients found it easy to mark specific spots on the dermatome chart. All 90 records could be used. 

Mean ST and standard deviation obtained by the first measurement was 1,22 +/- 0,85mA. Mean ST and standard deviation obtained by the second measurement was 1,32 +/- 0,82mA. For the Bland Altman plot we determined the average difference between the two measurements to be 0,0078 +/- 0,23mA. The limits of agreement, defined as the average difference plus or minus two times the standard deviation of the differences, were -0,45mA and 0,46mA. Of the 90 recordings, 83 (92%) were within the limits of agreement. 

The correlation plot showed a strong positive correlation between the first and second measurement of ST (r² = 0.924, p < 0.001). 
There was no difference in reliability between the different electrode configurations.

Of the 90 records, 81 (90%) were perceived at the same location at both measurements. Cohen’s kappa coefficient almost shows a perfect agreement between the first and second measurement of PLoS (p<0,001, Cohen's kappa (κ)=0,79).
Interpretation of results
A nearly perfect correlation for the ST and an almost perfect agreement for the PLoS was seen. Therefore the sensory responses upon stimulation of the different electrode configuration during programming is repeatable.
Concluding message
The use of dermatome chart with coordinates at which the patients mark the place where they feel electrical stimulation on sacral neuromodulation is a repeatable tool. The use of this “sensory passport” is advised to record as baseline document for patients started on sacral neuromodulation as it can be used in set up and troubleshooting sessions.
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Disclosures
Funding None Clinical Trial Yes Public Registry No RCT No Subjects Human Ethics Committee Committee for Medical Ethics UZA-UAntwerp Helsinki Yes
28/03/2024 07:02:02