Study design, materials and methods
A retrospective review of consecutive 418 patients (age range 22-94 years, median 61 years, 128 (30%) men) having intravesical Botox A injections for refractory non-neurogenic OAB symptoms under the care of 4 consultant surgeons between 2006 and 2018 was conducted. The outcome of treatment was categorized using a 5 point Patient Global Impression of Improvement (PGI-I) scale at the last follow up appointment or when contacted by telephone if last review was over 6 months ago. Successful outcomes were defined as PGI-I scores of 1 and 2 (good effect and partially good effect). Patient outcomes were correlated with the pre-operative urodynamic findings, including presence of urge urinary incontinence (OAB-wet), idiopathic detrusor overactivity (IDO), peak DO pressure, bladder capacity at onset of first DO, and evidence of bladder outlet obstruction (BOO). Duration of voiding detrusor contraction was noted in urodynamic studies with a valid voiding phase; however, studies with no evidence of voluntary detrusor contraction, where void was initiated on top of underlying DO, or where the intra-vesical catheter was expelled part-way through the void were excluded. Statistical analysis was done by Students T-Test and Chi Square Test and significance was determined at P < 0.05.
Interpretation of results
Intravesical Botox A was significantly more successful in women with urodynamically proven idiopathic detrusor overactivity (75%) comparing with men (60%) and women with OAB in absence of detrusor overactivity (62%). Successful outcomes were significantly associated with increased duration of voiding detrusor contractions but not with any other urodynamic parameters.