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Dog model for studying detrusor instability secondary to acutely induced variable bladder outlet obstruction
Author(s) -
Riehmann Morten,
Holder Christopher R.,
Saban Ricardo,
Nielsen Knud T.,
Rhodes Patsy R.,
Heisey Dennis,
Bruskewitz Reginald C.
Publication year - 1998
Publication title -
the prostate
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.295
H-Index - 123
eISSN - 1097-0045
pISSN - 0270-4137
DOI - 10.1002/(sici)1097-0045(19980215)34:3<182::aid-pros5>3.0.co;2-k
Subject(s) - medicine , urology , bladder outlet obstruction , cystometry , denervation , urinary bladder , urinary bladder neck obstruction , neck of urinary bladder , urinary incontinence , prostate , cancer
BACKGROUND Involuntary detrusor contractions often cause irritative symptoms such as urgency and incontinence. A dog model for acutely induced variable bladder outlet resistance was developed to investigate the possible role of prostatic afferent nerve fibers in the development and maintenance of detrusor instability. METHODS Fifty‐eight mongrel dogs (weight range 19.5–36.5 kg) were divided into five groups: group I (n = 11) had surgically induced bladder outlet obstruction. Group II (n = 14) had urinary obstruction and bilateral sectioning of the lowest branches of the pelvic plexus supplying the prostate. Group III (n = 10) had prostate denervation only. Groups IV (n = 10) and V (n = 13) were sham‐operated and controls, respectively. In the obstructed groups (I and II), an artificial urinary sphincter (length 4.5–6.0 cm) was placed around the bladder neck and connected to a reservoir placed subcutaneously to allow postoperative adjustments of urinary resistance. All dogs were evaluated at baseline and postoperatively at 1, 3, and 6 months with uroflowmetry, postvoid residual urine volume, cystometry as well as serum creatinine, and urinalysis. RESULTS Occurrences of detrusor instability were not associated with prostatic denervation input. The mean peak flow rates decreased significantly in the obstructed groups at all follow‐ups, but did not change significantly in the nonobstructed groups. Postoperatively, the mean maximum bladder capacity was significantly decreased for groups I and II only. However, a significant correlation between maximum bladder capacity and maximum detrusor pressure could not be detected at any time point in any of the groups. Mean postvoid residual urine volume varied considerably in all groups over time. Creation of a urinary model of infravesical obstruction was associated with considerable problems. CONCLUSIONS In our dog model of bladder outlet obstruction, prostatic sensory nerve fibers appear not to be involved in detrusor instability. Surgical induction of a constant model of bladder outlet obstruction was difficult even in a large animal. The observations from the present study raise questions about the validity of obstructive urinary animal models. Prostate 34:182–190, 1998. © 1998 Wiley‐Liss, Inc.