A double-blinded randomized multicentre study to investigate the effect of changes in stimulation parameters on sacral nerve stimulation for constipation.
OBJECTIVE
Sacral nerve stimulation (SNS) may be offered to patients with constipation who have failed to improve with conservative treatment. The response to SNS is variable, with a significant loss of efficacy in some patients. An increased frequency of stimulation may improve the efficacy of SNS for faecal incontinence. This study aimed to see if alteration of the pulse width or frequency improved the outcome for those with constipation.


METHODS
Eleven patients with constipation currently being treated by SNS were recruited from three centres. They were randomized to five different protocols of stimulation each applied for 5 weeks. Group 1 used standard settings (pulse width 210 μs, frequency 14 Hz); in the other four groups (Groups 2-5) the pulse width and/or frequency were halved or doubled. Patients and investigators were blinded to the group allocation.


RESULTS
The Cleveland Clinic constipation score varied significantly between the five groups. Group 1 achieved the lowest score mean (± SD) 13.4 (± 4.4) (P = 0.03). The number of digitations per defaecation was the lowest in Group 4, 90 μs and 14 Hz (P < 0.01). No other variable changed significantly. Standard settings were the most preferred by the recruited patients.


CONCLUSIONS
Alteration of pulse width or frequency of stimulation had no significant effect on the outcome of SNS for constipation.
The Sir Alan Parks Department of Physiology, St Mark's Hospital and Academic Institute, Harrow, UK.
G P
GP
Thomas
Department of Surgical Gastroenterology, Aarhus University Hospital, Aarhus, Denmark.
J
J
Duelund-Jakobsen
The Sir Alan Parks Department of Physiology, St Mark's Hospital and Academic Institute, Harrow, UK.
T C
http://orcid.org/0000-0001-9883-6700
TC
Dudding
The Sir Alan Parks Department of Physiology, St Mark's Hospital and Academic Institute, Harrow, UK.
E
E
Bradshaw
The Sir Alan Parks Department of Physiology, St Mark's Hospital and Academic Institute, Harrow, UK.
R J
RJ
Nicholls
GI Physiology Unit, University College Hospital, London, UK.
A
A
Alam
GI Physiology Unit, University College Hospital, London, UK.
A
A
Emmanuel
Barts Health NHS Trust, London, UK.
N
N
Thin
Barts Health NHS Trust, London, UK.
C H
CH
Knowles
Department of Surgical Gastroenterology, Aarhus University Hospital, Aarhus, Denmark.
S
S
Laurberg
The Sir Alan Parks Department of Physiology, St Mark's Hospital and Academic Institute, Harrow, UK.
C J
CJ
Vaizey
D000328:Adult; D000368:Aged; D003248:Constipation / Q000503:physiopathology / Q000628:therapy*; D003672:Defecation / Q000502:physiology*; D004311:Double-Blind Method; D004599:Electric Stimulation Therapy / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008160:Lumbosacral Plexus; D008297:Male; D008875:Middle Aged; D011788:Quality of Life; D016896:Treatment Outcome; D055815:Young Adult
SNS; constipation; neuromodulation