Hypothesis / aims of study
Refractory overactive bladder (OAB) refers to failure of response to initial therapy whether because of inefficacy or intolerability. Although 12-week percutaneous tibial nerve stimulation (PTNS) is considered standard treatment of refractory overactive bladder, it is both costly and time consuming. We postulated that a shortened 6- week therapy is effective and compared its efficacy to sham in the treatment of refractory OAB
Study design, materials and methods
Fifty seven non-neurogenic OAB adult patients were randomized to 6- week PTNS group or sham. All had been refractory OAb cases who failed one or more treatment option, provided informed consent and their condition is not secondary to neuropathis disorder. Randomization using closed labels was carried out and each in each arm, 50 patients competed at least 6 months follow up. The PTNS group (25 patients) was treated with active PTNS, the sham group (25 patients) received a placebo treatment using a 34 gauge needle placed in the medial part of the gastrocnemius muscle. Both groups had one session, lasted 30 minutes, performed once weekly for 6 consecutive weeks. The primary outcome to assess symptoms improvements using OAB symptom score (OABSS) as well as 3-day voiding diaries at baseline, 7th week, 3rd, and 6th month. Pad test was also performed in OAB wet cases.
Student t test was used to compare continuous variables while Chi squared was used for non- continuous parametes.
Interpretation of results
Symptoms in OABSS significantly improved in PTNS over sham group, at the 3 visits with p values 0.007, 0.001 and 0.005 respectively. Voiding diary showed significant improvement in PTNS ; p value of difference between groups was 0.001. However, pad test in those with OAB –wet type (3 out of 8 in PTNS group as compared to 4 out of 9 in sham group) showed non-significant difference at 6 months between the 2 groups (p is 0.6)
Adverse events in the form of mild ankle bruising was seen in 1 case in PTNS group, while 4 patients complained of pain at needle site from the PTNS group versus 2 from sham group