CHAPTER 13
Abdominal Wall and Hernias
Test Taking Tips
• Know how to approach a hernia and the indications for hernia repair in a cirrhotic patient.
• Know the anatomy of the femoral canal. Try to know the various approaches to fixing a femoral hernia and be aware of the different scenarios regarding femoral hernias, like when to use mesh versus primary repair, depending on the viability of the hernia contents.
• Know what complications can occur during a laparoscopic hernia repair. Tacks put out laterally can damage the lateral femoral cutaneous nerve. Tacks placed on the inferior aspect of Cooper ligament can potentially injure the corona mortis.
ANATOMY
FIGURE 13-1. Cross-sectional anatomy of the abdominal wall above and below the arcuate line of Douglas. The lower right abdominal wall segment shows clearly the absence of an aponeurotic covering of the posterior aspect of the rectus abdominis muscle inferior to the arcuate line. Superior to the arcuate line, there are both internal oblique and transversus abdominis aponeurotic contributions to the posterior rectus sheath. (Reproduced with permission from Moore KL, Dalley AF, eds. Clinically Oriented Anatomy. 4th ed. Philadelphia: Lippincott Williams & Wilkins; 1999:185.)
What are the 9 layers of the abdominal wall?
Skin, subcutaneous tissue, superficial fascia, external oblique muscle, internal oblique muscle, transversus abdominis muscle, transversalis fascia, preperitoneal adipose and areolar tissue, and peritoneum
Inguinal (Poupart) ligament
What directions do the fibers of the external oblique course?
Superolateral to inferomedial
What directions do the fibers of the internal oblique course?
Inferolateral to superomedial
What directions do the fibers of the transversus abdominis course?
Transverse
Where does the aponeurosis, which is originally divided into anterior and posterior lamella that envelops the rectus abdominis muscle, begin to course anteriorly to the rectus abdominis muscle and become part of the anterior rectus sheath?
Semicircular line (of Douglas/arcuate line)
FIGURE 13-2. Hesselbach triangle as originally described (left) and as accepted today (right). Note that part of supravesical fossa lies within triangle. (Modified from Skandalakis PN, Skandalakis LJ, Gray SW, Skandalakis JE. Supravesical hernia. In: Nyhus LM, Condon RE, eds. Hernia. 4th ed. Philadelphia: JB Lippincott; 1995:400–411, with permission.)
What are the borders of Hesselbach triangle?
Inguinal ligament inferiorly, lateral margin of the rectus sheath medially, and inferior epigastric vessels laterally
What makes up the floor of Hesselbach triangle?
Transversalis fascia
What structures course through the preperitoneal space?
Inferior epigastric artery and vein; median umbilical ligament (urachus—remnant of fetal allantoic stalk); medial umbilical ligaments (vestiges of fetal umbilical arteries); falciform ligament
What are the 9 potential spaces of the abdomen?
Right subphrenic; left subphrenic; right paracolic gutter; left paracolic gutter; subhepatic; supramesenteric; inframesenteric; lesser space; pelvis
PHYSIOLOGY
What is the function of the peritoneum?
To promote sequestration and removal of bacteria from the peritoneal cavity, control the amount of fluid in the peritoneal cavity, and facilitate the migration of inflammatory cells from the microcirculation into the peritoneal cavity
What is the most reliable method to help determine the cause of ascites?
The serum-ascites albumin gradient (SAAG)
How do you calculate the SAAG?
Serum albumin concentration – ascites albumin concentration
What does a SAAG <1.1 g/dL signify?
Absence of portal hypertension (biliary ascites, nephrotic syndrome, pancreatic ascites, peritoneal carcinomatosis, post-op lymphatic leak, serositis with connective tissue disease, tuberculous peritonitis)
What does a SAAG >1.1 g/dL signify?
Presence of portal hypertension (alcoholic hepatitis, Budd-Chiari syndrome, cardiac ascites, cirrhosis, fulminant liver failure, massive liver mets, myxedema, portal vein thrombosis)
How much albumin should be given for every liter of ascites removed after large volume paracentesis (>5 L)?
6 to 8 g of albumin/L of ascites removed
Most common malignancy associated with chylous ascites:
Lymphoma
Term for bacterial infection of ascitic fluid in the absence of an intra-abdominal, surgically treatable source of infection:
Spontaneous bacterial peritonitis
What is the management of spontaneous bacterial peritonitis?
Third-generation cephalosporin (eg, ceftriaxone)
Treatment for tuberculous peritonitis:
Antituberculous drugs (isoniazid and rifampin daily for 9 months commonly used)
Initial treatment for peritoneal dialysis–associated peritonitis:
Intraperitoneal administration of antibiotics (usually first-generation cephalosporin)
Treatment for recurrent/persistent peritoneal dialysis-associated peritonitis:
Removal of the dialysis catheter and resumption of hemodialysis
What disease entails a mucous-secreting tumor coating the peritoneum and filling the peritoneal cavity with mucus and large loculated cystic masses?
Pseudomyxoma peritonei
Treatment for pseudomyxoma peritonei:
Drainage of mucus and intraperitoneal fluid
Peritonectomy and omentectomy with cytoreduction of primary and secondary tumor implants
Right colectomy for appendiceal adenocarcinoma or total abdominal hysterectomy and bilateral salpingo-oophorectomy for ovarian carcinoma
Post-op intraperitoneal chemo/mucolytics
Term for the dilated superficial paraumbilical veins in this seen with portal venous obstruction:
Caput medusae
What nodal system do the supraumbilical lymphatic vessels drain?
Axillary lymph nodes
What nodal system do the infraumbilical lymphatic vessels drain?
Superficial inguinal lymph nodes
Where does visceral pain from inflammation of the stomach, duodenum, or biliary tract (foregut) localize?
Epigastrium
Where does visceral pain from inflammation of the small intestine, appendix, or right colon (midgut) localize?
Periumbilical region
Where does visceral pain from inflammation of the left colon and rectum (hindgut) localize?
Hypogastrium
Why is visceral pain felt in the midline rather than lateralize?
Organs transmit sympathetic sensory afferents to both sides of the spinal cord.
Where would you expect referred pain with irritation of the diaphragm?
Shoulder pain
Where would you expect referred pain with acute biliary tract disease?
Scapular pain
Where would you expect referred pain with retroperitoneal inflammation?
Testicular or labial pain
DISEASES
Make the diagnosis: a newborn is noted to have passage of meconium and mucus from the umbilicus in the first few days of life:
Patent omphalomesenteric duct
What is the treatment for a patent omphalomesenteric duct?
Laparotomy with excision of the fistulous tract
How can an umbilical polyp (persistence of distal omphalomesenteric duct) be differentiated from an umbilical granuloma?
Umbilical polyp will not disappear after silver nitrate cauterization; umbilical granuloma will disappear after silver nitrate cauterization
FIGURE 13-3. Diastasis recti visible in the midepigastrium with Valsalva maneuver. The edges of the rectus abdominis muscle, rigid with voluntary contraction, are palpable along the entire length of the bulging area. This should not be mistaken for a ventral hernia. (Reproduced from Brunicardi FC, Andersen DK, Billiar TR, et al. Schwartz’s Principles of Surgery. 9th ed. http://www.accessmedicine.com. Copyright © The McGraw-Hill Companies, Inc. All rights reserved.)
What is the treatment for a vesicocutaneous fistula (patent urachus)?
Excision of the urachal remnant with closure of the bladder if needed
Term for a midline protrusion of the anterior abdominal wall secondary to thinning of the linea alba in the epigastrium with intact transversalis fascia:
Diastasis recti
Treatment for diastasis recti:
Reassurance
How is a rectus sheath hematoma usually managed?
Rest and analgesics, correction of coagulopathy, and blood transfusion if necessary
How do you manage a rectus sheath hematoma that progresses despite nonoperative measures?
Angiographic embolization of the bleeding vessel or operative evacuation of the hematoma and hemostasis (uncommon).
What is the treatment of an abdominal wall desmoid tumor?
Complete resection with a tumor-free margin with or without adjuvant radiation; if deemed unresectable, it can be treated with radiation therapy alone or with antiproliferative agents and cytotoxic chemotherapy.
What are the 2 most widely used groups of noncytotoxic drugs used for the palliation of abdominal wall desmoid tumors?
Antiestrogens (Tamoxifen) and nonsteroidal anti-inflammatory drugs (NSAIDs) (Sulindac)
What are clinical characteristics suggestive of an abdominal wall malignancy?
Fixation to the abdominal wall, fixation to abdominal organs, recent increase in size, size >5 cm, and nonreducible lesion arising from below the superficial fascia
How is the definitive diagnosis of an abdominal wall sarcoma made?
Core needle biopsy (choose this one on the test) or by incisional biopsy oriented in the same plane as the underlying muscle.
Treatment for an abdominal wall sarcoma:
Resection with tumor-free margins with reconstruction accomplished primarily, with myocutaneous flaps, or with prosthetic meshes.
Treatment for an omental cyst:
Local excision
Most common malignancy of the omentum:
Metastases
The greater omentum derives its arterial blood supply from which arteries:
Omental branches of the right and left gastroepiploic arteries
Make the diagnosis: a patient presents with acute right lower quadrant abdominal pain and is explored for suspected appendicitis and is subsequently found with enlarged mesenteric lymph nodes and a normal appendix:
Acute mesenteric lymphadenitis
Infection with what organism is associated with acute mesenteric lymphadenitis in children?
Yersinia enterocolitica
Term for a rare inflammatory disease of the mesentery characterized by fat necrosis, acute and chronic inflammation, and fibrosis:
Mesenteric panniculitis
Treatment of mesenteric panniculitis:
Usually resolves spontaneously; if it does not resolve, can try corticosteroids or other anti-inflammatory/immunosuppressive agents.
Term for a congenital hernia in which the small intestine herniates behind the mesocolon:
Mesocolic (paraduodenal) hernia
Operative management for a patient with a right mesocolic (paraduodenal) hernia:
Incise the lateral peritoneal reflections along the right colon with reflection of the right colon and cecum to the left without opening the hernia neck (could injure superior mesenteric vessels).
Operative management for a patient with a left mesocolic hernia:
Incise the peritoneal attachments and adhesions along the right side of the inferior mesenteric vein; reduce herniated small intestine from beneath the inferior mesenteric vein; return inferior mesenteric vein to the left side of the base of the small bowel mesentery; close the neck of the hernia by suturing the peritoneum adjacent to the vein to the retroperitoneum.
Most common location for a mesenteric hernia:
Near the ileocolic junction
Treatment for a mesenteric hernia:
Reduce the hernia and close the mesenteric defect
Most common primary malignancy of the mesentery:
Desmoid tumor
Treatment for desmoid tumor of the mesentery:
Surgical resection versus watchful waiting with sulindac and antiestrogen therapy versus imatinib mesylate (Gleevec)
Treatment for a retroperitoneal abscess:
Antibiotics and CT-guided drainage; if not amenable to percutaneous drainage or if fails to resolve with percutaneous drainage, then perform operative drainage through a retroperitoneal approach.
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