# Femoral, Umbilical, and Rare Abdominal Wall Hernias
## Overview
While inguinal and incisional hernias dominate surgical practice, femoral, umbilical, and rare abdominal wall hernias (Spigelian, obturator, lumbar, and others) present unique diagnostic and surgical challenges. These hernias have variable incarceration rates and may require specific operative approaches. The general surgeon must recognize their clinical presentations and understand the anatomic basis for repair.
## Femoral Hernia
### Anatomy
A femoral hernia protrudes through the femoral canal, inferior to the inguinal ligament. The femoral canal boundaries are the inguinal ligament and iliopubic tract anteriorly, Cooper ligament and pectineus fascia posteriorly, lacunar ligament medially, and femoral vein laterally. The femoral canal is the most medial compartment of the femoral sheath (with structures arranged lateral to medial as artery, vein, and canal). The rigid boundaries of the femoral canal account for the high incarceration and strangulation rate.
### Epidemiology
Femoral hernias constitute 3 to 5% of all groin hernias. They are more common in women (female-to-male ratio of 4:1), though inguinal hernias remain the most common groin hernia even in women. The incidence is higher in elderly and multiparous women. Femoral hernias have the **highest strangulation rate** of all abdominal wall hernias, with 15 to 20% presenting with incarceration.
### Diagnosis
A femoral hernia presents as a mass inferior and lateral to the pubic tubercle, in contrast to an inguinal hernia which lies superior and medial. It often presents emergently with incarceration or bowel obstruction and may be difficult to differentiate from an inguinal hernia clinically. CT scan or ultrasound confirms the diagnosis and differentiates it from lymphadenopathy, saphenous varix, or psoas abscess.
### Surgical Approaches
The **preperitoneal (posterior) approach** is preferred for both elective and emergent repair. Accessed through a lower midline or Pfannenstiel incision, or laparoscopically via TEP or TAPP, it allows direct visualization of the femoral canal from above, mesh placement covering the femoral, direct, and indirect spaces, and optimal access for bowel assessment if strangulation is present.
The **inguinal (anterior) approach** uses a standard inguinal incision to access the femoral canal from above through the transversalis fascia. The McVay repair sutures the conjoint tendon to Cooper ligament and requires a relaxing incision. Mesh plug insertion into the femoral canal is an option but remains controversial.
The **infra-inguinal (low) approach** provides direct access below the inguinal ligament over the hernia bulge but offers limited visualization and higher recurrence. It is appropriate for small, easily reducible hernias but not ideal when bowel viability is questionable.
The **laparoscopic approach (TEP or TAPP)** is excellent for femoral hernia repair, allowing comprehensive coverage of all groin hernia sites with mesh covering the entire myopectineal orifice.
## Umbilical Hernia
### Epidemiology and Anatomy
Umbilical hernias are the most common hernia in infants, with a prevalence of 10 to 25% of live births (higher in African American and premature infants). Pediatric umbilical hernias close spontaneously by age 4 to 5 years in most cases. Adult umbilical hernias are acquired and associated with obesity, pregnancy, ascites, and chronic cough. The defect occurs at the umbilical ring through the linea alba, commonly containing preperitoneal fat, omentum, and bowel in larger defects. The incarceration rate in adults is 5 to 15%.
### Pediatric Management
Observation until age 4 to 5 years is appropriate since most pediatric umbilical hernias close spontaneously. Surgery is indicated if the hernia has not closed by age 5, the defect exceeds 2 cm, the hernia is symptomatic or incarcerated, or a proboscis-type hernia is present. Simple primary suture repair (vest-over-pants or simple closure) is the standard technique.
### Adult Management
For **small defects (less than 2 cm)**, recent RCTs and HerniaSurge guidelines increasingly favor mesh repair even for small defects due to lower recurrence (1 to 5% with mesh versus 10 to 30% with primary suture repair). For **larger defects (greater than 2 cm)**, mesh repair is mandatory, with sublay/retrorectus mesh preferred and IPOM for larger defects. In patients with **ascites**, fluid must be controlled before repair due to very high recurrence rates with uncontrolled ascites. Emergency repair is necessary for incarceration, strangulation, or skin ulceration and rupture.
### Umbilical Hernia in Cirrhosis
The prevalence reaches up to 20% in cirrhotic patients with ascites. Elective repair should follow optimization (paracentesis, TIPS if needed). Emergency repair is indicated for incarceration, necrosis, or rupture -- the latter known as **Flood syndrome**, in which spontaneous rupture leads to peritonitis. Mortality of emergent repair in cirrhotic patients is 5 to 15%.
## Spigelian Hernia
### Anatomy
A Spigelian hernia occurs through the Spigelian aponeurosis, located between the lateral edge of the rectus muscle and the linea semilunaris. It most commonly occurs at or below the arcuate line in the lower abdomen -- the "Spigelian hernia belt" between the umbilicus and anterior superior iliac spine. The hernia typically passes through the internal oblique and transversus abdominis aponeurosis but remains covered by the external oblique, making it an interparietal hernia. This explains why clinical detection is difficult -- the hernia is neither visible nor palpable externally.
### Diagnosis
Spigelian hernias are often "occult," with low clinical examination sensitivity. Patients present with lateral abdominal wall pain and sometimes a palpable mass present only with Valsalva. **CT scan** is the diagnostic study of choice with sensitivity exceeding 95%. Ultrasound may demonstrate dynamic herniation with Valsalva.
### Management
Surgical repair is recommended for all Spigelian hernias due to a high incarceration risk of up to 20%. Options include open repair (direct incision over the defect with primary fascial closure for small defects and mesh reinforcement in the sublay position) and laparoscopic repair (TAPP or IPOM approach with mesh coverage). Robotic approaches are increasingly used.
## Obturator Hernia
### Anatomy and Epidemiology
An obturator hernia protrudes through the obturator foramen alongside the obturator nerve and vessels, passing through the obturator canal bounded by the obturator membrane and superior pubic ramus. This is a rare hernia (less than 1% of all hernias) that classically affects the elderly, thin, multiparous female -- the "little old lady hernia." It often presents with small bowel obstruction, and Richter-type herniation (partial bowel wall incarceration) is common.
### Diagnosis
The **Howship-Romberg sign** is pathognomonic: pain along the medial thigh to the knee, exacerbated by internal rotation, extension, or abduction of the hip due to obturator nerve compression. The hernia is often missed clinically and diagnosed by CT scan during a workup for small bowel obstruction, showing a bowel loop herniating through the obturator foramen between the pectineus and obturator externus muscles.
### Management
Repair is usually emergent due to bowel obstruction. A **midline laparotomy** is the most common approach, allowing reduction of contents, assessment of bowel viability with resection if needed, and closure of the defect with mesh or suture. A **laparoscopic approach** is feasible, with preperitoneal mesh placement similar to a TAPP approach. Mortality ranges from 12 to 70% due to delayed diagnosis and advanced age with comorbidities.
## Lumbar Hernia
Two anatomic triangles are involved. The **superior lumbar triangle (Grynfeltt-Lesshaft)**, bounded by the 12th rib superiorly, internal oblique anteriorly, and erector spinae posteriorly with a floor of quadratus lumborum and transversalis fascia, is the more common site. The **inferior lumbar triangle (Petit)** is bounded by the iliac crest inferiorly, external oblique anteriorly, and latissimus dorsi posteriorly with a floor of internal oblique. Lumbar hernias may be congenital (rare) or acquired (post-traumatic, post-surgical from flank incisions or iliac crest bone graft harvest, or spontaneous). Repair uses mesh reinforcement via open or laparoscopic approaches.
## Epigastric Hernia
Epigastric hernias involve defects through the linea alba between the xiphoid and umbilicus, usually containing preperitoneal fat and rarely bowel. They are typically small and often multiple. Symptomatic hernias are managed with primary suture repair for very small defects and mesh reinforcement for larger or recurrent ones.
## Richter Hernia
A Richter hernia involves incarceration of only the antimesenteric border of the bowel wall. It can strangulate without causing complete bowel obstruction, which is particularly dangerous because the absence of obstructive symptoms delays diagnosis. It is common in small, rigid-necked defects such as the femoral canal and laparoscopic trocar sites and carries a high risk of necrosis and perforation.
## Amyand and Littre Hernias
An **Amyand hernia** is an inguinal hernia containing the appendix. If the appendix is inflamed, appendectomy with tissue repair is performed (mesh is generally avoided with infection present). If the appendix is normal, it is reduced and a standard mesh repair performed; appendectomy in this setting is controversial. A **Littre hernia** contains a Meckel diverticulum and may present with incarceration or inflammation.
Anatomical illustration showing the femoral canal and its boundaries as seen from an anterior view: inguinal ligament (anterior), Cooper ligament (posterior), lacunar ligament (medial), and femoral vein (lateral). Include the relationship of the femoral hernia to the inguinal hernia, showing the femoral hernia emerging below and lateral to the pubic tubercle versus the inguinal hernia above and medial to it. Label the femoral artery, vein, and nerve from lateral to medial.
Cross-sectional diagram of the lateral abdominal wall at the level of the Spigelian hernia belt showing the layers: external oblique, internal oblique, transversus abdominis, transversalis fascia, and peritoneum. Illustrate the Spigelian hernia protruding through the internal oblique and transversus abdominis aponeurosis but remaining deep to the intact external oblique (interparietal hernia), explaining why it is clinically occult. Label the linea semilunaris and the Spigelian aponeurosis.
Anatomical illustration of the obturator foramen showing the obturator canal with the obturator nerve and vessels passing through it, and a Richter-type hernia with the antimesenteric border of a small bowel loop incarcerated through the obturator canal. Include a clinical diagram demonstrating the Howship-Romberg sign with pain referral pattern along the medial thigh to the knee.
## Clinical Pearls
Femoral hernias have the highest incarceration and strangulation rate of all groin hernias, and all femoral hernias should be repaired at diagnosis. A groin hernia that presents inferior and lateral to the pubic tubercle is a femoral hernia, whereas one superior and medial is an inguinal hernia. Umbilical hernias in adults should be repaired with mesh even for small defects, as primary suture repair has recurrence rates of 10 to 30%. Spigelian hernias are "occult" hernias covered by the external oblique and are often missed on physical exam -- CT is the study of choice. The Howship-Romberg sign (medial thigh pain with internal rotation of the hip) is pathognomonic for obturator hernia. A Richter hernia involves only the antimesenteric bowel wall and can strangulate without causing complete bowel obstruction, delaying diagnosis. Umbilical hernias in cirrhotic patients with ascites carry high morbidity, and ascites must be controlled preoperatively; emergent repair for Flood syndrome (spontaneous rupture) is life-threatening. Pediatric umbilical hernias generally close spontaneously by age 4 to 5 and do not require surgery unless the defect is large, symptomatic, or persistent.
## References
- HerniaSurge Group. International guidelines for groin hernia management. *Hernia*. 2018;22(1):1-165.
- Henriksen NA, Montgomery A, Kaufmann R, et al. Guidelines for treatment of umbilical and epigastric hernias from the European Hernia Society and Americas Hernia Society. *Br J Surg*. 2020;107(3):171-190.
- Skandalakis LJ, Androulakis J, Colborn GL, Skandalakis JE. Obturator hernia: embryology, anatomy, and surgical applications. *Surg Clin North Am*. 2000;80(1):71-84.
- Larson DW, Farley DR. Spigelian hernias: repair and outcome for 81 patients. *World J Surg*. 2002;26(10):1277-1281.