PELVIC AND PROSTATIC TRAUMA
Penetrating trauma to the prostate gland is rare as it is protected from penetrating objects by the surrounding bony pelvis. However, penetrating injury to the prostate is possible from broken pelvic bones as a consequence of pelvic fracture. The real concern with prostatic trauma, however, involves injury to the posterior and prostatomembranous urethra that lie superior to the urogenital diaphragm. This is most commonly a consequence of forceful blunt trauma to the pelvis.
Posterior urethral injuries may occur in three ways: (1) Internal trauma with perforation of the membranous and prostatic urethra during unskilled use of rigid endoscopy instruments such as sounds or cystoscopes. This usually results in only temporary injury to the prostatic parenchyma but can lead to more long-term “acquired” diverticula, prostatic abscess, or prostatorectal ﬁstula. (2) External trauma with direct injury to the prostatic capsule by either missiles or sharp objects through the perineum. Although rare, these usually involve injury to Colles fascia and to the urogenital diaphragm (see Plate 2-19) as well. (3) The most common and clinically important injuries involve damage to the prostatomembranous urethra from fractures of the bony pelvis. The prostate is ﬁrmly held in a relatively ﬁxed position by the dense puboprostatic ligaments that attach its anterior surface to the under surface of the os pubis (see Plate 4-1) and by its attachment by the urethra to the pelvic diaphragm inferiorly. However, the prostatomembranous urethra, measuring 1 cm long between the apex of the prostate and the urogenital diaphragm, is very fragile and easily subjected to disruption from shear force. Pelvic fracture and particularly separation of the symphysis pubis often dislocates the prostate and severs the prostatomembranous urethra from the urogenital diaphragm. Alternatively, bony os pubis fragments from the rami and ischium may sever the prostatomembranous urethra. Lastly, any injury violent enough to disrupt the puboprostatic ligaments usually also injures the prostatomembranous urethra, even with minimal bony fractures.
Prostatomembranous urethral rupture should be considered in all cases of trauma to the pelvic girdle. The inability to urinate and blood at the urethral meatus are particularly important symptoms and signs. A rectal examination may reveal superior displacement of the prostate from its normal position, often to the point at which it becomes nonpalpable. A retroperitoneal hematoma or urine extravasation may also accumulate and, when signiﬁcant, may be palpated as a soft mass on rectal examination. Urethral catheterization should not be attempted in cases of pelvic injury and blood at the meatal tip unless retrograde urethrogram imaging reveals an intact urethra, as this procedure could convert a partial to complete urethral disruption.
The majority of posterior urethral injuries usually require urgent treatment of shock, bleeding, and fracture management. With urethral bleeding, the possibility of a coexistent intra- or extraperitoneal bladder rupture must also be considered. With an intact urethra and a small extraperitoneal bladder rupture, the simple insertion and maintenance of catheter drainage may be sufﬁcient for early management. For intraperitoneal bladder rupture, surgical exploration and repair is generally needed.
With complete prostatomembranous urethral disruption, primary surgical reanastomosis of the urethra or primary realignment of the urethral ends over a catheter, performed immediately or in a delayed fashion, are necessary. Primary surgical repair is performed through perineal, transpubic, or suprapubic exposure and is partly determined by the limitations of patient positioning resulting from pelvic fracture and stability. Evacuation or drainage of extravasated urine is also advised.
Failure to anastomose or accurately approximate the severed urethral ends leaves a mucosal defect that results in extensive cicatrix and stricture formation in the urethral gap. A signiﬁcant delay in urethral realignment because of other life-threatening conditions allows a displaced prostate to become ﬁxed by ﬁbrous tissue, and complicates alignment surgery. In addition to urethral stricture formation, erectile dysfunction is a common complication of this form of urethral injury.