Urethral opening pressure in patients with myelodysplasia

We evaluated 60 patients with myelodysplasia using the urethral opening pressure (UOP) which is defined as the total intravesical pressure at the moment when urine passes through the external sphincter by the Credé or the Valsalva maneuver. Twenty nine of the patients showed UOP value greater than 35 cmH2O and 31 below 35 cmH2O. In the high pressure group, patients showed a tendency to preserve sphincter activity and had mild paralysis of the lower extremities. In contrast, most of patients in the low pressure group showed an underactive sphincter and severe paralysis of the lower extremities. The incidence of deterioration of the upper urinary tract, vesicoureteral reflux (VUR) and bladder deformity were significantly high in the high pressure group than those in the low pressure group (75.9% vs 16.1%, 72.4% vs 22.6%, 82.8% vs 29.0%, respectively, P < 0.05). During the follow-up period (42 months on average), the voiding methods were changed in 15 patients from the Credé maneuver to clean intermittent catheterization, and total of 12 operations were performed (10 antiVUR operation and two with an ileocystoplasty). Finally, approximately 90% of the patients in both the high and the low pressure groups were evaluated as improved or stable in the upper urinary tract, VUR and bladder deformity after conservative or surgical managements. UOP is considered to be one of the useful parameters to select the high risk patient in the urological management of myelodysplastic patients.