 Study design, materials and methods In this open label pilot institutional review board approved study, ten women with a primary disorder of urethral sphincter relaxation elevated urethral pressure profile UPP, sphincter volume and abnormal EMG presenting with obstructed voiding n5 or in complete urinary retention n5 are recruited from a single tertiary referral centre. Baseline symptoms are being assessed using the IPSS questionnaire, and urinary flow and post-void residual volume were measured. After 2 lidocaine injection, 100U of onabotulinumtoxintypeA is being injected into the striated urethral sphincter, divided on either side, under EMG guidance. Patients are being reviewed at weeks 1, 4 and 10 post-treatment and symptoms are reassessed using the IPSS questionnaire, and urinary flow and post-void residual volume are being measured. The UPP is being repeated at week 4. 