Abdominal Wall Hernias A Case of Three Hernias and Anatomy of Inguinal, Femoral, and Obturator Regions

Abdominal Wall Hernias A Case of Three Hernias and Anatomy of Inguinal, Femoral, and Obturator Regions David Furfaro, HMS 3 rd Year Medical Student Gillian Lieberman, MD Radiology Core Clerkship August 2012

Presentation Outline 1. Case Presentation 2. Differential Diagnosis 3. Small Bowel Obstruction A. Imaging Approach to Diagnosis B. Differential Diagnosis for Cause 4. Hernias 1. Anatomy and Types of Hernias 2. Imaging 3. Management

F.L. ED Presentation CC: Vomiting, abdominal pain, and leg pain HPI: 86 year old female began having pain along anterior right thigh about one week prior to presentation. Soon after, she began experiencing diffuse, colicky abdominal pain. She has been vomiting and unable to eat x 6 days. Denies flatus or bowel movements for past few days. ROS: Oliguria for few days. Denies fevers, chills, chest pain or tightness, cough, SOB, jaundice, urinary symptoms, melena, BRBPR

F.L. History PMH: Hypertension, spinal arthritis, remote history of breast cancer s/p mastectomy PSH: Hysterectomy 14 years ago, Mastectomy 30 years ago, left wrist surgery 30 years ago Meds: Atenolol Allergies: NKDA SH: Remote history smoking. No ETOH or illicit drug use FH: Mother died stomach cancer

F.L. Physical Vitals: 98.2 112 143/65 32 95% on RA General: Awake, alert, no acute distress, cooperative HEENT: Anicteric sclera, EOMI, PERRL Neck: Supple, JVP not elevated, no lumps or masses CV: RRR, normal S1 and S2, no m/r/g Lungs: Crackles in bases of left lung Abdomen: Bowel sounds present all quadrants. Soft, nondistended. Tender to palpation on right side. Slight guarding, no rebound tenderness Ext: Reducible right inguinal hernia. 2+ pulses bilaterally Neuro: A&Ox3, cranial nerves intact. 5/5 strength and intact light sensation in all extremities

F.L. Differential Diagnosis Anatomic: Bowel obstruction Mechanical Functional Strangulated hernia (hiatal, inguinal, other) Gallstone ileus Cholelithiasis Nephrolithiasis Metabolic / Electrolyte Hypercalcemia Hypokalemia Hypernatremia Hyponatremia Uremia Diabetic Ketoacidosis (first presentation diabetes) Gastroenteritis Biliary pathology Cholecystitis, cholangigits etc. Appendicitis Pancreatitis Right sided diverticulitis Pyelonephritis Peritonitis Hepatitis Abscess Pneumonia with diaphragmatic irritation Vascular Mesenteric ischemia Ischemic colitis SMA syndrome Cysts or neoplasms of ovaries, fallopian tubes Endometriosis Trauma Viscus rupture Solid organ laceration or rupture Hematoma Malignancy Metastatic tumor Carcinomatosis Primary tumors colon, pancreas, liver etc. Lymphoma Benign tumors Infectious / Inflammatory: Gynecologic Adnexal pathology

F.L. Labs 141 101 67 3.9 29 1.7 127 11.2 9.0 259 34.5 N: 87.1 L: 6.4 M: 6.1 E: 0.2 Bas 0.1 Bands 28% (earlier CBC) PT: 11. 7 PTT: 24.6 INR: 1.1 Elevated BUN and Cr. BUN:Cr > 20 White count WNL, but bands and left shift

Suspected Complete Bowel Obstruction Diffuse abdominal pain Nausea Vomiting Absences of flatus and bowel movements Dehydration oliguria, pre-renal azotemia Previous abdominal surgery and presence of hernia Classic findings absent in L.B. Distended abdomen Red flags: Left shift on WBC differential

Diagnostic Imaging Approach for Bowel Obstruction LBO Barium enema Non-Diagnostic Silva AC, Pimenta M, Guimaraes LS. Small bowel obstruction: what to look for. Radiographics. 2009 Mar-Apr;29(2):423-39

Appropriate Imaging for SBO American College of Radiology. ACR Appropriateness Criteria : Suspected complete or high-grade partial SBO. Available at: http://www.acr.org/~/media/acr/documents/appcriteria/diagnostic/suspectedsmallbowelobstruction.pdf. Accessed August 2012

Appropriate Imaging for SBO American College of Radiology. ACR Appropriateness Criteria : Suspected complete or high-grade partial SBO. Available at: http://www.acr.org/~/media/acr/documents/appcriteria/diagnostic/suspectedsmallbowelobstruction.pdf. Accessed August 2012

Abdominal Plain Film in Bowel Obstruction Controversy in the literature about utility Some studies show 80-90% sensitivity, while others show diagnosis rates as low as 30-70% (ACR, 2010) Rarely helpful in determining site or cause of obstruction (Maglinte et al. 1996) Recent studies have shown that more experienced radiologists have higher rates of detection (ACR, 2010) Still considered by many to be first line imaging for suspected bowel obstruction

Our Patient: KUB Image 1 Dilated small bowel Can infer transition point because paucity of gas in the colon Incidental finding left thoracolumbar scoliosis and degenerative changes Upright KUB, Image from PACS, BIDMC

Our Patient: KUB Image 2 Lateral decubitus KUB. Image from PACS, BIDMC Air fluid levels

Approach to Abdominal Plain Film Concerning for Obstruction 1. Look for dilated loops of bowel 2. Determine if large bowel or small bowel 3. Mechanical or functional Mechanical see marked dilation and a transition point Functional see mild distension of entire bowel with no transition point 4. Rule of 3s Exception is focal ileus = sentinel loop Bowel lumen dilated > 3 cm Thickened folds > 3mm More than 3 air fluid levels Case of F.L. Present Small bowel Markedly dilated and transition point mechanical Dilated > 3cm More than 3 air-fluid levels Diagnosis = Mechanical Small Bowel Obstruction

Differential Diagnosis for Mechanical Bowel Obstruction In the lumen Foreign body Bezoar Gallstone Worm ball Intussusception Fecal impaction In the wall Benign Adenoma Leiomyoma Lipoma Malignant Primary adenocarcinoma Metastases melanoma Lymphoma Extrinsic causes Adhesions -2/3 Hernia Adjacent mass Volvulus

Why we care / complications of SBO Strangulation: bowel wall edema and increasing intraluminal pressure compromised perfusion Ischemia and necrosis ensues Fever and leukocytosis Progress to perforation Most common with closed loop obstructions and hernias Furukawa A, Kanasaki S, Kono N, Wakamiya M, Tanaka T, Takahashi M, Murata K. Ct Diagnosis of Acute Mesenteric Ischemia from Various Causes. AJR. 2009, 192 (2): 408-416.

HERNIAS REVIEW OF HERNIA IMAGING VIA CASE OF F.L.

Imaging Recommendations and Algorithm

Imaging Recommendations and Algorithm Silva AC, Pimenta M, Guimaraes LS. Small bowel obstruction: what to look for. Radiographics. 2009 Mar-Apr;29(2):423-39

Our Patient: SBO on CT Axial, C- Abdominal CT Image from PACS, BIDMC Air fluid level Dilated small bowel 41.2 mm Coronal, C- Abdominal CT Image from PACS, BIDMC

Our Patient: Serial CT Images - 1 Umbilical hernia Decompressed colon Axial, C- CT Abdomen. Image from PACS, BIDMC

Our Patient: Serial CT Images - 2 Hernia Inguinal ligament Axial, C- CT Abdomen. Image from PACS, BIDMC

Our Patient: Serial CT Images - 3 Axial, C- CT Abdomen. Image from PACS, BIDMC Inguinal hernia Decompressed bowel entering hernia sac Decompressed bowel leaving the hernia It would be easy to confuse this inguinal hernia as the site of obstruction, but there is no transition point; it is all decompressed bowel

Our Patient: Serial CT Images - 4 Decompressed bowel entering inguinal hernia Decompressed bowel leaving the hernia On sagittal view it is clearer that all the bowel in the inguinal hernia is decompressed and there is no transition point Sagittal, C- CT Abdomen. Image from PACS, BIDMC

Our Patient: Serial CT Images - 5 Where is the transition point then? Follow this loop of bowel Axial, C- CT Abdomen. Image from PACS, BIDMC

Our Patient: Serial CT Images - 6 Where is the transition point then? Bowel entering obturator foramen Axial, C- CT Abdomen. Image from PACS, BIDMC

Our Patient: Serial CT Images - 7 Where is the transition point then? Follow the loop of bowel Axial, C- CT Abdomen. Image from PACS, BIDMC

Our Patient: Serial CT Images - 8 Where is the transition point then? Obturator hernia Axial, C- CT Abdomen. Image from PACS, BIDMC

Our Patient: Serial CT Images - 9 Where is the transition point then? Follow this loop of bowel. Dilated bowel starting to enter obturator hernia Coronal, C- CT Abdomen. Image from PACS, BIDMC

Our Patient: Serial CT Images - 10 Where is the transition point then? Loop of bowel going through the obturator foramen Coronal, C- CT Abdomen. Image from PACS, BIDMC

Our Patient: Serial CT Images - 11 Where is the transition point then? Obturator hernia Coronal, C- CT Abdomen. Image from PACS, BIDMC

Our Patient: Serial CT Images - 12 Where is the transition point then? Bowel loop in obturator hernia Coronal, C- CT Abdomen. Image from PACS, BIDMC

Our Patient: Serial CT Images - 13 Where is the transition point then? Bowel loop in obturator hernia Coronal, C- CT Abdomen. Image from PACS, BIDMC

Our Patient: Serial CT Images - 14 Where is the transition point then? Follow this loop of bowel out of the obutrator hernia Coronal, C- CT Abdomen. Image from PACS, BIDMC

Our Patient: Serial CT Images - 15 Where is the transition point then? Follow this loop of bowel out of the obutrator hernia Coronal, C- CT Abdomen. Image from PACS, BIDMC

Our Patient: Serial CT Images - 16 Where is the transition point then? Follow this loop of bowel out of the obutrator hernia Coronal, C- CT Abdomen. Image from PACS, BIDMC

Our Patient: Serial CT Images - 17 Decompressed bowel leaving the obturator hernia Dilated bowel entered the hernia and decompressed bowel exited, so this is the transition point and site of obstruction Coronal, C- CT Abdomen. Image from PACS, BIDMC

Our Patient: Obutrator Hernia on KUB? Loop of bowel going into obturator hernia? This is a zoomed in portion of the KUB viewed earlier. It is possible that seeing the obturator hernia on this imaging modality Upright KUB. Image from PACS, BIDMC

Review of Hernias and Anatomy

Hernias in General Protrusion of an organ, fascia, or tissue through the wall of the cavity that normally contains it Bulge on outside, depending on type, location and size See on imaging CT is normally diagnostic Reducible hernia sac can be pushed back into cavity easily Incarcerated hernia cannot be reduced Strangulated incarcerated hernia with a compromised blood supply Lead to necrotic bowel and perforation Surgical emergency

Types of Hernias Brain herniation Diaphragmatic hernia Hiatal hernia Type 1: sliding Type 2: paraesophageal Type 3: mixed Type 4: abdominal organ herniated above diaphragm Congenital diaphragmatic hernia Bochdalek postero-lateral hernia Morgagni anterior hernia Abdominal wall hernias

Abdominal Wall Hernias Inguinal Femoral Umbilical Obturator Richter s hernia Incisional Parastomal Epigastric Spigelian hernia Littre hernia Lumbar hernia Many, many more

Menu of Radiologic Tests for Hernias Computed Tomography currently test of choice Sonography (US) Dynamic exam can detect transient hernias High sensitivity and specificity for inguinal and femoral hernias May miss in obese patients Plain film rarely useful Magnetic Resonance Imaging Increasing in use due to lack of ionizing radiation Herniogram 40 50 ml of contrast injected into peritoneum under fluoroscopic guidance Images taken at rest and straining / coughing Invasive May miss incarcerated hernias

Imaging for Hernias American College of Radiology. ACR Appropriateness Criteria : Palpable abdominal mass. Available at: http://www.acr.org/~/media/acr/documents/appcriteria/diagnostic/palpableabdominalmass.pdf Accessed August 2012

Abdominal Wall Anatomy Brooks, D. Overview of Abdominal Wall. UpToDate 2012. http://tinyurl.com/kga7aa7

Inguinal Hernias - Anatomy Inguinal canal Inferior wall / floor = inguinal ligament From ASIS to pubic tubercle Thickening of aponeurosis external oblique fascia Anterior wall = external abdominal Superficial ring is opening in this layer Poster wall = transversalis fascia Deep inguinal ring is opening in this layer Superior wall = transversus abdominus and internal oblique Canal contents Spermatic cord in men Round ligament of uterus in women Ilioinguinal nerve

Inguinal Canal Anatomy Image from CFAA Science Anatomy and Physiology: Abdomen/ Pelvis: Inguinal Canal. Available online at : http://cfaascience.wordpress.co m/2010/10/22/anatomy-andphysiology-abdomenpelvisinguinal-canal/

Hesselbach s Triangle Image available online at: http://academic.amc.edu/martino/grossanatomy/site/medical/lab%20manual/gastrointestinal/answers/anterior%20wall1.htm

Inguinal Hernias Most common type of hernia In groin 96% are inguinal, 4% are femoral More common in men (9:1) Femoral are more common in women, although inguinal still most common type found in women Indirect inguinal hernia Most common type can be congenital from patent processus vaginalis extension of peritoneum in development Hernia sac through internal ring, lateral to inferior epigastrics Direct inguinal hernia Through Hesselbach s triangle Hernia sac through weakness in posterior wall of inguinal canal Cannot always distinguish type on imaging Look for inferior epigastric vessels

Companion Patient #1: Indirect Hernia Inferior epigastric vessels Hernia sac with loop of bowel in it Hernia is lateral to inferior epigastric vessels, so is an indirect hernia Axial, C+ CT abdomen. Sinha R, Rajiah P, Tiwary P. Abdominal Hernias: Imaging Review and Historical Perspectives. Current Problems in Diagnostic Radiology. 2007 Jan-Feb; 36(1): 30-42

Femoral Hernias Rare, < 10% of all hernias, but 40% present with incarceration or strangulation Defect in attachment of trasversalis fascia to pubic tubercle Occur in femoral triangle Posterior / inferior to inguinal ligament Medial to femoral vessels: NAVEL Occur more in older women because weaker pelvic floor muscles Further weakened by child birth

Anatomy of Femoral Region Image available online at http://tinyurl.com/m5

Distinguishing Femoral and Inguinal Hernias on CT Look for position relative to inguinal ligament Two other tricks from review of 215 groin hernia CTs and 46 femoral hernia CTs Look if sac extends medial past pubic tubercle likely inguinal Look if sac compresses femoral veins likely femoral

Companion Patient #2: Femoral Hernia Black arrow head = pubic tubercle White arrow = compression of the femoral vein by the hernia sac Axial, C+ CT abdomen. Suzuki S, Furui S, Okinaga K, Sakamoto T, Murata J, Furukawa A, Ohnaka Y. Differentiation of Femoral Versus Inguinal Hernia: CT Findings. AJR. August 2007; 189(2): W78-W83.

Our Patient: Inguinal Hernia Axial, C- Abdominal CT, Image PACS, BIDMC No compression of vessels Hernia extends medially past pubic tubercle

Umbilical Hernia Opening in the linea alba Linea alba = aponeurosis of rectus sheath formed by fascia of abdominal muscles Separates left and right rectus muscle Congenital or acquired Acquired is more common in females than males 3:1 Due to increased abdominal pressure from obesity, distension, ascites or pregnancy

Companion patient #3: Umbilical Hernia Axial, C+ CT abdomen. Sinha R, Rajiah P, Tiwary P. Abdominal Hernias: Imaging Review and Historical Perspectives. Current Problems in Diagnostic Radiology. 2007 Jan-Feb; 36(1): 30-42

Obturator Hernia Hernia through obturator foramen Obturator foramen is formed by ischium and pubis bones and Obturator membrane within creates the obturator canal Obturator canal contains the obturator artery, vein, and nerve which supplies the medial compartment of the thigh Referred to as little old lady hernia due to demographic Accounts for 0.2 0.4 % obstructions and has 25% mortality rate due to difficult diagnosis and patient population

Image available at: http://www.miklosandmoore.com/tot1.php

Companion patient #4: Obturator Hernia White arrows identify obturator hernia sacs. A. Upright KUB. B. Axial, C- CT abdomen Sinha R, Rajiah P, Tiwary P. Abdominal Hernias: Imaging Review and Historical Perspectives. Current Problems in Diagnostic Radiology. 2007 Jan-Feb; 36(1): 30-42

Abdominal Wall Hernias Inguinal Femoral Umbilical Obturator Richter s hernia counts one sidewall of bowel, usually antimesenteric Can cause ischemia without obstruction Incisional at site of previous incision Parastomal adjacent to stoma, similar to incisional Epigastric through linea alba above umbilicus Spigelian hernia through linea semilunaris Littre hernia Involves a Meckel s diverticulum Lumbar hernia Many, many more

References Kendrick ML. Partial small bowel obstruction: clinical issues and recent technical advances. Abdom Imaging. 2009; 34(3):329. Maglinte DD, Reyes BL, Harmon BH et al. Reliability and role of plain film radiography and CT in diagnosis of small-bowel obstruction. AJR 1996; 167(6):1451-1455. Shrake PD, Rex DK, Lappas JC, Maglinte DD. Radiographic evaluation of suspected small bowel obstruction. Am J Gastroenterol 1991;86(2): 175-178. Silva AC, Pimenta M, Guimaraes LS. Small bowel obstruction: what to look for. Radiographics. 2009 Mar-Apr;29(2):423-39 Sinha R, Rajiah P, Tiwary P. Abdominal Hernias: Imaging Review and Historical Perspectives. Current Problems in Diagnostic Radiology. 2007 Jan-Feb; 36(1): 30-42 Small WC, Rose TA, Rosen MP, Blake MA, Baker ME, Cash BD, Fidler JL, Greene FL, Jones B, Katz DS, Lalani T, Miller FH, Sudakoff GS, Tulchinsky M, Yee J. Suspected Small-Bowel Obstruction. ACR Appropriateness Criteria. 1996, last reviewed 2010. Suzuki S, Furui S, Okinaga K, Sakamoto T, Murata J, Furukawa A, Ohnaka Y. Differentiation of Femoral Versus Inguinal Hernia: CT Findings. AJR. August 2007; 189(2): W78-W83.