Study design, materials and methods
Patient having urinary incontinence and symptoms of detrusor overactivity, were invited to try electrical stimulation of sole of the foot. Patients were asked to withdraw drugs pertaining to treatment of detrusor overactivity (if any) and were also asked to maintain voiding chart one week prior to the treatment. Twenty patients, meeting key inclusion/exclusion criteria, consented for the study.
Following inclusion/exclusion criteria were used for the study:-
Inclusion criteria:
1. Patient with spinal cord injury having at least one leak per day as reported in the voiding chart.
2. CMG proven detrusor overactivity
3. On Clean Intermittent Catheterization
4. Presence of Ankle jerk
5. Age-18 years and above.
Exclusion criteria:
1. Peripheral neuropathy
2. Urinary tract infection
3. Pregnant women
4. Any psychiatric ailment
5. Symptoms of stress urinary incontinence
6. Presence of any implantable devices such as pacemaker, cochlear implant or any metallic implantable plate were contraindication for this study.
All the patients maintained voiding chart for two weeks during the treatment. Cystometrogram was done on day 1 and 15. Electrical stimulation was given half-an-hour daily for fourteen consecutive days. The Parameters for stimulation were 200 μs pulse width, rectangular pulses with current strength ranging between 10–80 mA and frequency 20 Hz (1). Cathode was placed at the level of medial arch of foot while anode was placed approximately 2cm apart at the level of metatarsophalangeal (MTP) joint. The electrodes were customized to fit the site of stimulation for each patient. In-house developed stimulator costing less than Rs 2000, was used. Satisfaction questionnaire were taken on day 15. Voiding chart data was analyzed using novel Cumulative Voiding Chart Index(CvCi). In CvCi , each voiding chart parameter was graded either -1 (worsen), 0 (no change) or +1 (improved) as a representation of state of the bladder (pre and post-intervention). Wilcoxon signed-ranked test was used for CMG data while Binomial distribution for voiding chart data as test of significance. The p-value<0.05 was considered as significant. Study was approved by Institutional review board and ethics committee.
Results
Twenty subjects were stimulated at the sole of foot for two weeks.
There was improvement in reflex volume, cystometric capacity and maximum detrusor pressure. Following treatment, 12 subjects showed increase, 6 showed decrease and 2 had no significant change in reflex volume. There was significant improvement in cystometric capacity of 14 subjects, 3 did not show much improvement and remaining persons showed reduced bladder capacity. Thirteen patients had reduction, 3 had increase and 4 had no significant change in maximum detrusor pressure.
Eighteen patients showed improvement in bladder function and two subjects did not show any signs of improvement as reported by CvCi score derived from voiding chart.
Interpretation of results
The p-value for improvement in cystometric capacity (p-value-0.04) and maximum detrusor pressure (p-value-0.03) was statistically significant while p-value of reflex volume (p-value-0.13) was not significant.
The CvCi scoring shows that 18 patients had improvement in bladder capacity / number of leaks /maximum urine output after two weeks of electrical stimulation therapy while 2 patients did not shown any improvement.
The Binomial distribution test conducted on improved population against not improved population was found to have significant p value(p-value 0.001).
In regards to satisfaction with feedback questionnaire, all patient were satisfied with treatment methodology and easy to use procedure.