FEMALE UROLOGY

Preoperative pressure-flow studies: useful variables to predict the outcome of continence surgery
Digesu GA, Khullar V, Cardozo L, Sethna F, Salvatore S
Department of Urogynaecology, King’s College Hospital, London, UK
BJU Int. 2004; 94: 1296-9

• Objective: To determine whether the acceleration of flow rate (AFR), pressure flow variables and urethral pressure profilometry (UPP) measurements might have a role in evaluating women with urodynamic stress incontinence (USI), to predict the surgical outcome and de novo detrusor overactivity after Burch colposuspension.
• Patients and Methods: Women with a urodynamic diagnosis of USI (209) who had a modified Burch colposuspension were assessed retrospectively. The AFR, the opening (ODP) and closing detrusor pressure (CDP), DP at maximum flow rate and UPP values were calculated for each woman before surgery.
• Results: The preoperative AFR was significantly higher in women who developed de novo detrusor overactivity after surgery. The women who had persistent USI after colposuspension had significantly lower preoperative ODP and CDP than women who were continent after colposuspension. Other variables were not significantly different between the groups of women.
• Conclusions:The AFR and ODP appear to be useful preoperative measures to predict the outcome of continence surgery and the emergence of de novo detrusor overactivity.
  
  
• Editorial Comment
  The authors review a population of patients who underwent Burch colposuspension and analyze urodynamic variables (acceleration of flow rate, pressure flow variables and urethral pressure profiles) both preoperatively and postoperatively. The findings were then used to examine their predictive power for surgical outcome and de novo detrusor overactivity. The authors found that acceleration of flow rate and opening detrusor pressure appears to have promise as a preoperative gauge in the incidence of de novo detrusor overactivity while urethral pressure profiles did not provide any particularly illuminating factor.
  The authors should be commended for their thorough review of urodynamic variables to help assist the surgeon in predicting and potentially avoiding inadvertent outcomes from anti-incontinence surgery. Their discussion of acceleration of flow rate is interesting for this urodynamic test does not have an extremely popular penetration as a preoperative urodynamic study. That the authors noted that the urethral pressure profiles were not particularly useful is not overly surprising in view that past authors have found no significant difference in resting urethral pressure profile and functioning urethral profile before and after anti-incontinence surgery (1). In addition, the potential puzzling nature of urethral pressure profiles pre and post operatively has been discussed by others (2).
  The authors should be complimented on their discussion section, especially their thoughts on the association of opening and closing detrusor pressure and successful surgery. I recommend this paper highly to those surgeons actively performing active anti-incontinence operations as well as those with an active interest in urodynamics.

References
1. Faysal MH, Constantinou CE, Rother LF, Govan DE: The impact of bladder neck suspension on the resting and stress urethral pressure profile: a prospective study comparing controls with incontinent patients preoperatively and postoperatively. J Urol. 1981; 125: 55-60.
2. Rydhstrom H, Iosif CS: Urodynamic studies before and after retropubic colpo-urethrocystopexy in fertile women with stress urinary incontinence. Arch Gynecol Obstet. 1988; 241: 201-7.

Dr. Steven P. Petrou
Associate Professor of Urology
Mayo Clinic College of Medicine
Jacksonville, Florida, USA