Urethral catheterization is the most frequent manipulation of the urinary tract. It is routinely performed for diagnostic and therapeutic reasons in both urologic and nonurologic diseases.1–11 Catheters may be inserted as an in-and-out procedure for immediate drainage, left in with a self-retaining device for short-term drainage, or left indwelling for long-term drainage.6,7 Although this is one of the more routinely performed procedures in the Emergency Department, great care must be taken to avoid lower urinary tract injury, reduce the introduction of infection, and minimize patient discomfort. The basic principles underlying urethral catheterization are gender-neutral.6,7 It is important to respect the patient's need for modesty and privacy as much as possible.
The genitourinary system is frequently divided into upper and lower urinary tracts. The former refers to the kidneys and ureters or those structures above the bony pelvis. The lower urinary tract includes the bladder and urethra or those structures contained within or below the bony pelvis. Although the entire urinary tract may be catheterized, it is the lower tract, namely the urethra, which will be the focus of this chapter.
Averaging 4 cm in length, the female urethra is rarely a focus of difficulty. Most of the confusion related to urethral catheterization in the female results from poor anatomic knowledge of the external genitalia (Figure 142-1). The clitoris is often mistaken for the urethral meatus. This can result in catheter-related trauma, bleeding, patient discomfort, and frustration. After lateral retraction of the labia minora and exposure of the vaginal vault, the cephalad-most structure is the clitoris. Traveling in a caudal direction, the orifices encountered are the urethra, followed by the vagina, and the anus.
External anatomy of the female genitourinary tract.
The male urethra is most often the site of catheter-associated difficulty.3 In contrast to the female, the male urethra may extend upward of 20 cm in length and follows a tortuous course. The urethra is named based on the anatomic structure it traverses or travels with. The distal-most portion of the male urethra is the meatus, followed by the penile, bulbar, membranous, and prostatic portions (Figure 142-2). Resistance to the advancement of a catheter may occur at any point along the course of the urethra as a result of meatal stenosis, urethral strictures, urethral valves, false urethral passages, enlarged prostates, inflammatory processes, malignant processes, bladder neck contractures, urethral disruptions, and bladder neck disruptions. A careful clinical history and thorough physical examination will, in most cases, uncover these causes. The two most common sites that may be difficult for the catheter to pass are the junction between the bulbar and membranous urethra and the bladder neck.
Anatomy of the male genitourinary tract.