IS THERE A CLINICALLY SIGNIFICANT CHANGE IN PRESSURE-FLOW STUDY VALUES AFTER URETHRAL INSTRUMENTATION IN PATIENTS WITH LOWER URINARY-TRACT SYMPTOMS

Objective To determine the effect of urethral instrumentation on press ure-flow study values and subsequent grading of bladder outflow obstru ction (BOG) in men with lower urinary tract symptoms (LUTS) using supr apubic intravesical pressure monitoring. Patients and methods Seventy- two men with LUTS underwent pressure-flow study using suprapubic intra vesical pressure monitoring. The urethra was then instrumented success ively with a 12 F catheter and a 17 F cystoscope, and a further pressu re-now study recorded after each procedure. Standard pressure-now vari ables were measured for the three recordings, The presence and degree of obstruction were determined using commonly recognized grading syste ms, i.e. the Abrams-Griffiths nomogram, the linear passive urethral re sistance ratio (LPURR) and the urethral resistance algorithm (URA). Re sults There were statistically significant differences in the detrusor pressure at maximum now and detrusor opening pressure between the uni nstrumented and instrumented studies (12 F and 17 F) but no difference in peak now rates between the groups or in the Abrams-Griffiths numbe r or URA value between studies, Using the LPURR, there was a tendency to a lower obstruction class after urethral instrumentation, ranking a s 17 F > 12 F > no instrumentation. Conclusions The changes seen after urethral instrumentation represent no more than the biological intrai ndividual variation normally seen in pressure-now studies and do not l ead to a clinically significant change in obstruction class.