Study design, materials and methods
We reviewed the medical records of patients who underwent SNM permanent implantation from 2012.7 to 2019.7. Forty-one patients with both neurogenic bladder and bowel dysfunction were evaluated using the NBD score before the testing phase and at follow up. The NBD score is a symptom-based score developed by Krogh et al[1]. which is used to assess the severity of clinical colorectal dysfunction in patients with neurogenic decease or injury. The NBD score is a questionnaire consisting of 10 items related to impaired quality of life caused by bowel symptoms, including frequency of defecation (0–6 points), duration of time for each defecation (0–7 points), uneasiness, headache or perspiration during defecation (0–2 points), regular use of tablets to combat constipation (0–2 points), regular use of drops to combat constipation (0–2 points), digital stimulation or evacuation of the anorectum (0–6 points), frequency of fecal incontinence (0–13 points), medication to combat fecal incontinence (0–4 points), flatus incontinence (0–2 points) and perianal skin problems (0–3 points). The overall NBD score ranges between 0 and 47 points. A higher score indicates more severe bowel symptoms. The severity of NBD is classified into four grades: very minor (0–6); minor (7–9); moderate (10–13) and severe (14 and more).
Results
Overall, 41 patients who underwent permanent SNM implantation were included in the study. The mean age was 38±14.7 years (range 13–73 years), and the mean duration from the beginning of the test phase to discharge after permanent implantation was between 24 and 38 days. The Clinical and demographic characteristics of patients were in table 1.
The mean NBD score decreased from 11.0±5.83 before the testing phase to 5.2±5.32(n=41,P<0.05) after permanent implantation before discharge.
Before the testing phase, there were 9 patients of very minor grade, 10 of minor grade, 13 of moderate grade and 9 of severe grade. However, the overall severity of NBD tended to decrease after permanent implantation, with 26 patients of very minor grade, 7 of minor grade, 4 of moderate grade and 4 of severe grade.
From a longitudinal perspective, the NBD grade decreased in 21 (51.2%) patients and did not change in 20 (48.8%) patients (Table 2). However, in the 20 patients whose grade did not change, the mean NBD scores decreased from 8.6±5.00 to 7.2±6.07 (P < 0.05).
Interpretation of results
Patients with neurologic disease commonly suffer from bladder and bowel dysfunction (constipation and/or fecal incontinence), because the bladder and rectum have closely related somatic and autonomic innervation, and their voluntary control depends on a complete neural network. Sacral neuromodulation (SNM) can improve not only neurogenic lower urinary tract dysfunction but also bowel dysfunction in patients.
In our previous study[2], 23 patients with multiple bladder and/or bowel problems secondary to spinal cord disease or injury were treated with a preliminary test SNM. In the test phase, the rate of improvement in constipation (75.0%) was significantly higher than the rates of improvement in urgency frequency (64.7%), urinary incontinence (69.2%) and dysuria (29.4%). However, we focused on constipation rather than fecal incontinence in that study.
Therefore, in this retrospective study, we aimed to evaluate the effect of SNM in patients with NBD according to NBD scores which can evaluate constipation and fecal incontinence. This finding illustrates the success of SNM in reducing NBD symptoms.