The Bonney test: A reassessment, ,

OBJECTIVE: The purpose of this study was to reassess the effects of the Bonney test versus direct urethral compression and to introduce the Miyazaki-Bonney test. STUDY DESIGN: Thirty-seven patients with a diagnosis of genuine stress incontinence were studied. Each patient underwent a classic Bonney test, direct urethral compression, and a Miyazaki-Bonney test, while the following observations and measurements were made: (1) urethroscopic observation of the bladder neck and proximal urethra, (2) cotton swab resistance to withdrawal, and (3) proximal urethral pressure changes with use of a microtip catheter. In 16 of the patients cough pressure transmission (pressure transmission ratio) to the proximal urethra was measured before and during a Bonney test. Apart from the study group, four patients with clinical type III urethras were evaluated with the Bonney and Miyazaki-Bonney tests. RESULTS: The effects of the Bonney test and direct urethral compression were grossly different on urethroscopy, cotton swab resistance to withdrawal, and proximal urethral pressure changes. With the Bonney test, the average increase in urethral pressure was 52 cm H2O, whereas with direct urethral compression the urethral pressure was >250 cm H2O. With the Miyazaki-Bonney test there was little or no change in urethral pressure. Cough pressure transmission ratios before the Bonney test averaged 64%, whereas during the Bonney test they averaged 152%. The Miyazaki-Bonney tests did not prevent leakage in three patients with type III urethras. CONCLUSION: The Bonney test does not work by direct urethral compression but instead appears to produce continence by restoring the anterior vaginal wall hammock. The Miyazaki-Bonney test duplicates the effects of the Burch bladder neck suspension and may still be a valid prognosticator of surgical success. A modified Bonney test that can be standardized is presented as the Miyazaki-Bonney test.(Am J Obstet Gynecol 1997;177:9)