Abdominal Wall, Omentum, Mesentery, and Retroperitoneum
BASIC SCIENCE QUESTIONS
1. The inguinal ligament is the inferior-most part of which abdominal wall muscle?
B. Internal oblique
C. External oblique
D. Rectus abdominis
The inguinal ligament is the inferior-most edge of the external oblique aponeurosis, reflected posteriorly in the area between the anterior superior iliac spine and pubic tubercle. (See Schwartz 9th ed., p 1267.)
2. Which nerve root(s) supplies innervations to the skin of the umbilicus?
A. C3, 4, and 5
C. T4 and 5
Innervation of the anterior abdominal wall is segmentally related to specific spinal levels. The motor nerves to the rectus muscles, the internal oblique muscles, and the transversus abdominis muscles run from the anterior rami of spinal nerves at the T6 to T12 levels. The overlying skin is innervated by afferent branches of the T4 to L1 nerve roots, with the nerve roots of T10 subserving sensation of the skin around the umbilicus. (See Schwartz 9th ed., p 1269, and Fig. 35-1.)
FIG. 35-1. Dermatomal sensory innervation of the abdominal wall. (Reproduced with permission from Moore KL, Dailey AF (eds): Clinically Oriented Anatomy, 4th ed. Philadelphia: Lippincott Williams & Wilkins, 1999, p 188.)
1. Which of the following (see Fig. 35-2) is a Rocky-Davis incision?
The incision labeled E is the Rocky-Davis muscle-splitting incision, most commonly used for open appendectomies. If exposure is not adequate, a Weir extension (dotted line) can be performed. (See Schwartz 9th ed., p 1270.)
2. The best treatment for the condition shown in Fig. 35-3 is
A. Primary open repair
B. Open repair using mesh
C. Laparoscopic repair using mesh
This is the typical, epigastric bulge of diastasis recti, which in the vast majority of patients needs no treatment. Rectus abdominis diastasis (or diastasis recti) is a clinically evident separation of the rectus abdominis muscle pillars. This results in a characteristic bulging of the abdominal wall in the epigastrium that is sometimes mistaken for a ventral hernia despite the fact that the midline aponeurosis is intact and no hernia defect is present. Diastasis may be congenital, as a result of a more lateral insertion of the rectus muscles to the ribs and costochondral junctions, but is more typically an acquired condition, occurring with advancing age, in obesity, or after pregnancy. In the postpartum setting, rectus diastasis tends to occur in women who are of advanced maternal age, who have a multiple or twin pregnancy, or who deliver a high-birth-weight infant. Diastasis is usually easily identified on physical examination. Computed tomographic (CT) scanning provides an accurate means of measuring the distance between the rectus pillars and can differentiate rectus diastasis from a true ventral hernia if clarification is required. Surgical correction of rectus diastasis by plication of the broad midline aponeurosis has been described for cosmetic indications and for alleviation of impaired abdominal wall muscular function. However, these approaches introduce the risk of an actual ventral hernia and are of questionable value in addressing pathology. (See Schwartz 9th ed., p 1271.)
3. A 48-year-old patient presents with sudden onset of bilateral lower abdominal pain after spasmodic coughing. On examination, there is an 8-cm, tender mass in the mid lower abdomen that remains unchanged with contraction of the rectus muscles. Which of the following is the most likely diagnosis?
A. Ruptured aortic aneurysm
B. Obturator hernia
C. Spigelian hernia
D. Rectus sheath hematoma
This patient has a typical history for rectus hematoma and a positive Fothergill’s sign (a palpable abdominal mass that remains unchanged with contraction of the rectus muscles). Although rectus sheath hematomas are usually unilateral, if the hematoma is below the arcuate line, it may cross the midline. CT or MRI can be used to confirm the diagnosis. A spigelian hernia is herniation through the lateral rectus sheath, on the semilunar line. The oburator foramen is in the posterior pelvis, and obturator hernias usually present with bowel obstruction or medial thigh pain due to compression of the obturator nerve. A ruptured aortic aneurysm would usually present with back pain and a less prominent abdominal mass. (See Schwartz 9th ed., p 1272.)
4. The indications for surgery in a patient with a rectus sheath hematoma include
A. Persistent pain after 24 hours
B. Expanding hematoma after embolization
C. Need for transfusion
D. Need for ongoing anticoagulation
The primary indications for operating on a patient with a rectus sheath hematoma are hemodynamic instability and an expanding hematoma despite embolization. (See Schwartz 9th ed., p 1272, and Fig. 35-4.)
FIG. 35-4. Management algorithm for rectus sheath hematoma. Most patients present with a mass and/or pain and are managed without intervention. The potential for a rare catastrophic bleeding event must be recognized, however. Surgical evacuation is reserved for those circumstances in which clinical evidence of ongoing bleeding makes any other management option untenable. CBC = complete blood count; CT = computed tomography; OR = operating room.
5. Which of the following is the most important initial therapy for a patient with portal hypertension, ascites, and a tense umbilical hernia?
A. Primary repair with concurrent placement of a peritoneal venous shunt
B. Emergency primary repair to avoid hernia rupture
C. Medical therapy to control the ascites
D. Transjugular intrahepatic portocaval shunt followed by umbilical hernia repair
Treatment and control of the ascites with diuretics, dietary management, and paracentesis is the most appropriate initial therapy. Patients with refractory ascites may be candidates for transjugular intrahepatic portocaval shunting or eventual liver transplantation. Umbilical hernia repair should be deferred until after the ascites is controlled. (See Schwartz 9th ed., p 1273.)
6. In a patient with a permanent ileostomy and 4-cm infraumbilical midline incisional hernia, which of the following would be the most appropriate?
A. Open primary closure
B. Open mesh closure
C. Component separation
Although mesh repair would not be contraindicated in this patient, component separation has the advantage of no prosthetic material in a potentially contaminated wound.
Primary repair, even of small hernias (defects 3 cm), is associated with high reported hernia recurrence rates. In a randomized prospective study of open primary and open mesh incisional hernia repairs in 200 patients, investigators from the Netherlands found that after 3 years, recurrence rates were 43% and 24% for the two methods, respectively. Identified risk factors for recurrence were primary suture repair, postoperative wound infection, prostatism, and surgery for abdominal aortic aneurysm. These investigators concluded that mesh repair was superior to primary repair. In an effort to decrease the suture line tension associated with primary repair, Ramirez first described the components separation technique. Components separation entails the creation of large subcutaneous flaps lateral to the fascial defect followed by incision of the external oblique muscles and, if necessary, incision of the posterior rectus sheath bilaterally. These fascial releases allow for primary apposition of the fascia under far less tension than in simple primary repair. Components separation hernia repair is associated with a high wound infection risk (20%) and a recurrence rate of 18.2% at 1 year. Components separation is most applicable for the repair of incisional hernias when there are converging needs to (a) avoid the use of prosthetic materials, and (b) achieve a definitive repair. Most commonly this occurs in the setting of a contaminated or potentially contaminated surgical field. (See Schwartz 9th ed., p 1273.)
7. A 22-year-old man presents with localized peritonitis of the right lateral abdomen. He is afebrile, is eating, and has a white blood cell count of 12,000. CT scan demonstrates omental infarction. Which of the following is the most appropriate treatment?
A. A nonsteroidal anti-inflammatory agent and observation
B. Broad spectrum antibiotics, morphine with exploration if no improvement after 24 hours
C. Laparoscopic exploration to confirm the diagnosis and resect the infarcted omentum
D. Total omentectomy (open or laparoscopic)
In patients who are not toxic, supportive care will often result in resolution of the symptoms. Antibiotics are not indicated for this inflammatory condition. Laparoscopy should be considered if the diagnosis is not sure, or for progressive or severe symptoms. Resection of the infracted omentum leads to rapid resolution of the symptoms. A total omentectomy is not indicated. (See Schwartz 9th ed., p 1275.)
8. A 55-year-old woman presents with a palpable abdominal mass and abdominal pain. CT scan and exploration show scarring of the mesentery with shortening and retraction. The base of the mesentery is fibrotic and thickened. Following biopsy confirmation of your clinical diagnosis, which of the following is the best therapy for this patient?
A. Surgical debulking of the tumor
C. Chemotherapy and radiation therapy
This is the typical description of sclerosing mesenteritis. In most cases of sclerosing mesenteritis the process appears to be self-limited and may even demonstrate regression if followed with interval imaging studies. Clinical symptoms are very likely to improve without intervention, and therefore aggressive surgical treatments are generally not indicated. (See Schwartz 9th ed., p 1276.)
9. A 15-year-old girl presents with a mobile, 8-cm mid abdominal mass that moves freely from left to right but does not move superiorly or inferiorly. Which of the following is the most likely diagnosis?
A. Omental cyst
B. Mesenteric cyst
C. Ovarian cyst
D. Gastric duplication
Physical examination of a patient with a mesenteric cyst may reveal a mass lesion that is mobile only from the patient’s right to left or left to right (Tillaux’s sign), in contrast to the findings with omental cysts, which should be freely mobile in all directions. Although ovarian cysts are usually ballotable, they are rarely mobile. Gastric duplications are virtually never palpable. (See Schwartz 9th ed., p 1277.)
10. Which of the following drugs is associated with retroperitoneal fibrosis?
The strongest case for a causal relationship between medication and retroperitoneal fibrosis is made for methysergide, a semisynthetic ergot alkaloid used in the treatment of migraine headaches. Other medications that have been linked to retroperitoneal fibrosis include beta blockers, hydralazine, α-methyldopa, and entacapone, which inhibits catechol-O-methyltransferase and is used as an adjunct with levodopa in the treatment of Parkinson’s disease. The retroperitoneal fibrosis regresses on discontinuation of these medications. Omeprazole, Prozac, and Dapsone have not been associated with retroperitoneal fibrosis. (See Schwartz 9th ed., p 1280.)
11. Which of the following is the most appropriate treatment for retroperitoneal fibrosis?
A. Surgical débridement of potentially obstructing fibrosis
B. Prevention of obstruction with anticoagulation (for IVC thrombosis) and ureteral stenting (for ureteral obstruction)
C. High dose corticosteroids
Corticosteroids, with or without surgery, are the mainstay of medical therapy. Surgical treatment consists primarily of ureterolysis or ureteral stenting and is required in patients who present with moderate or massive hydronephrosis. Laparoscopic ureterolysis has been shown to be as efficacious as open surgery in addressing this problem. Patients with iliocaval thrombosis require anticoagulation, although the required duration of this therapy is unclear. Prednisone is initially administered at a relatively high dose (60 mg every other day for 2 months) and then gradually tapered over the next 2 months. Therapeutic efficacy is assessed on the basis of patient symptoms and interval imaging studies. Cyclosporin, tamoxifen, and azathioprine also have been used to treat patients who respond poorly to corticosteroids. (See Schwartz 9th ed., p 1280.)