Objectives: To search for relationships between phasic (P) and terminal (T) DO with age, urodynamic findings and sphincter behavior during involuntary detrusor contraction in woman.
Materials and methods: Urodynamic studies (triple lumen catheter 7F, seated position) of 164 successive women referred for LUTS with diagnosis of DO were reviewed. Patients were stratified in 4 sub-groups: pre- (18-44 y), peri- (45-54 y), post-menopause (55-74 y) and oldest old (= 75 y). The urethral sensor was positioned at the level of the maximum urethral closure pressure for sphincter behavior analysis. A variation of at least 5 cmH(2)O in pressure (detrusor or urethra) was chosen to assert DO or sphincter response. Sphincter response was classified as relaxation (re) before or during DO, or steady (st).
Results: Occurrence of P and TDO was similar: 77 P and 87 T. The PDO group was significantly younger (p = 0.0003). TDO was more frequent in patients with a history of neurological disease. The percentage of PDO remained almost constant in age groups, while that of TDO increased with age from 6.7% to 23.2% (p = 0.0013). Uninhibited contraction occurred at a smaller bladder volume in the P group: 149 ± 95 vs. 221 ± 113 mL (p < 0.0001). Steady sphincter predominated in the TDO subgroup: 45.9% vs. 32.1% and increased significantly in each DO sub-group of ≥ 75 y.
Conclusion: Steady sphincter during both P and TDO, and occurrence of TDO appear as specific of aging. The last result could be related to structural changes in the detrusor muscle with aging.