1541 DISTAL CORPUS CAVERNOSUM SMOOTH MUSCLE FIBROSIS DUE TO NON-ISCHAEMIC PRIAPISM- SHOULD EMBOLISATION BE PERFORMED EARLIER?

Abstract

INTRODUCTION AND OBJECTIVES: Non-ischaemic priapism is due to unregulated cavernous arterial inflow. Although rare, it is commonly associated with perineal or penile trauma. Since the venous outflow mechanism is unaffected the corpus cavernosum is perfused with oxygenated blood and therefore these patients can be managed conservatively. We report on our series of patients with non-ischaemic priapism who have developed fibrosis of the distal corpus cavernosum following a period of conservative treatment. METHODS: Over a 5 year period, 7 patients with non-ischaemic priapism presented to our unit. The mean age was 37.4 years (range 20 56). The etiology in 6 cases was secondary to a perineal injury and in 1 case conversion of an ischaemic priapism to a non ischaemic priapism following surgical intervention. The diagnosis of non-ischaemic priapism in all patients was based on the clinical history and examination, cavernosal blood gas analysis, colour duplex ultrasonography of the penis and pudendal angiography. 4 cases (57%) also underwent a penile MRI. RESULTS: Although the diagnostic tests confirmed non-ischaemic priapism, follow up Doppler studies and MRI penis showed the development of distal corpus cavernosum fibrosis. Pudendal artery super selective embolization was eventually performed in all of the patients, of which 2 (28.5%) patients underwent a second attempt at embolisation. On follow up these patients reported the development of erectile dysfunction due to poor distal penile tumescence in all cases and the penile MRI demonstrated distal corpus cavernosum fibrosis. Four patients (57%) eventually underwent insertion of a penile implant due to failed pharmacotherapies. A further 3 (43%) patients are using PDE-5 inhibitors. The conditions were reproduced in an in vitro model using precontracted strips of rabbit corpus cavernosum superfused at high pO2 levels. This showed that the smooth muscle tone reduced by 43% of the initial tone (n 4) after superfusion for 12 hours indicating irreversible smooth muscle dysfunction. CONCLUSIONS: The risk of ischaemic damage in non-ischaemic priapism is expected to be minimal due to the oxygenation of the corpus cavernosum being maintained. However, corpus cavernosum perfusion with higher than normal pO2 levels may result in oxidative stress due to the formation of reactive oxygen species (ROS). Irreversible damage to the smooth muscle is followed by the development of fibrosis, Based on these findings we suggest that superselective embolisation of these cases should be performed at the earliest opportunity.