A 65-year-old man comes to the emergency department due to severe lower abdominal pain and nausea. He also has not been able to urinate for the past 24 hours. The patient has a history of hypertension and benign prostatic hyperplasia. On examination, a large mass is palpable in the suprapubic area. Multiple attempts at urethral catheterization are unsuccessful, and an ultrasound-guided midline suprapubic cystostomy is planned. Besides the bladder wall, which of the following structures is most likely to be penetrated by the trocar and cannula during the procedure?

Question

A 65-year-old man comes to the emergency department due to severe lower abdominal pain and nausea.  He also has not been able to urinate for the past 24 hours.  The patient has a history of hypertension and benign prostatic hyperplasia.  On examination, a large mass is palpable in the suprapubic area.  Multiple attempts at urethral catheterization are unsuccessful, and an ultrasound-guided midline suprapubic cystostomy is planned.  Besides the bladder wall, which of the following structures is most likely to be penetrated by the trocar and cannula during the procedure?

Quizplus · Accepted Answer

11ec160b_35df_bfef_9249_f9f731a9f990_MD0001_00 This patient has a severe bladder outlet obstruction, with the bladder palpable above the pelvic brim. The superior surface of the bladder is covered with peritoneum and is found below coils of ileum or sigmoid colon. Along the lateral margins of the bladder, the peritoneum is reflected onto the lateral pelvic walls. The bladder is therefore extraperitoneal. As the bladder fills and bulges upward, it comes into direct contact with the anterior abdominal wall anteroinferior to the peritoneal space. In a suprapubic cystostomy, the trocar and cannula pierces the aponeurosis of the abdominal wall muscles, along with the layers of the superficial fascia, transversalis fascia, and extraperitoneal fat. However, the peritoneum is not entered (Choices B and E), reducing the risk of peritonitis and hemoperitoneum. (Choice C) The perineal membrane (inferior fascia of the urogenital diaphragm) spans the deep perineal pouch from the periosteum of the ischiopubic rami to the arcuate ligament of the pubis. It is penetrated by the urethra inferior to the bladder but would not be encountered in suprapubic cystostomy. (Choice D) The ureters enter the bladder posterolaterally at the lateral angle of the bladder. A suprapubic trocar enters anteriorly and will not encounter the ureters unless it passes through the body of the bladder. Educational objective: The bladder is extraperitoneal. In placement of a suprapubic cystostomy, the trocar and cannula will pierce the layers of the abdominal wall but will not enter the peritoneum.

A 65-Year-Old Man Comes to the Emergency Department Due to Severe