Femoral hernia overview

# Overview
Femoral hernia is the protrusion or bulge below the inguinal ligament, through the femoral canal, in the upper thigh. The rigid anatomy of the femoral canal predisposes these hernias to incarceration or strangulation, thus more than 44% of the cases of femoral hernia present in an acute setting with incarceration. Certain connective tissue diseases predispose the patients to developing femoral hernia. Femoral hernia is classified based on its anatomical relations on presentation. Most cases of femoral hernia present in females and the most common cause is an enlarged femoral ring. The female to male ratio is approximately 5 to 1. Femoral hernia must be differentiated from other diseases that cause swelling in the groin area. The diagnostic study of choice for femoral hernia is ultrasound, however in emergent cases that are difficult to diagnose CT scan is used to confirm the diagnosis. Surgery is the mainstay of treatment for femoral hernia. Immediate surgical intervention is needed in cases of incarceration or strangulation.

# Historical Perspective
Hernia means a protrusion, hernias have been present in humans since the beginning of time, and the first interventions can be dated as early as the fifteenth century in ancient Egypt. However interventions had always been reserved for very large protrusions or painful incarcerated hernias.

# Classification
Femoral hernia may be occasionally classified into several subtypes based on anatomical relation.

# Pathophysiology
A femoral hernia is the protrusion of the hernia sac through the femoral ring in to the femoral canal. The anatomy of the femoral canal is such that the neck is made up of rigid structures that predispose herniated bowel to strangulation and incarceration. The hernia sac contains small bowel which can predispose to intestinal obstruction. Some connective tissue diseases predispose the patient to developing femoral hernia. Malignancy is very rarely associated with femoral hernias, thus histopathological analysis is done routinely following a repair but shows incarcerated bowel on most occasions.

# Causes
The most common cause of femoral hernia is an enlarged femoral ring. Less common causes of femoral hernia include increased intra-abdominal pressure and pregnancy.

# Differentiating Femoral hernia overview from other diseases
Femoral hernia must be differentiated from other diseases that cause swelling in the groin area, such as inguinal hernia, femoral artery aneurysm, saphenous vein varicosity, lymphadenopathy and lipoma.

# Epidemiology and Demographics
The prevalence of femoral hernia is estimated to be 2% - 8% of all groin hernias. The incidence of femoral hernia increases with age, individuals commonly affected are between 40 -70 years of age. Females are more commonly affected than males.

# Risk Factors
Common risk factors in the development of femoral hernia include female gender, increasing age and a history of recurrent hernias.

# Screening
There is insufficient evidence to recommend routine screening for femoral hernia.

# Natural History, Complications, and Prognosis
If left untreated, 44%-86% of patients with femoral hernia may progress to develop strangulation or incarceration.

# Diagnosis

## Diagnostic study of choice
Ultrasound is the diagnostic study of choice for diagnosing femoral hernia as it has low cost, widespread availability and low risk of radiation exposure. If it is an emergent case with signs of incarceration that is difficult to diagnose based on clinical examination, an abdominal CT scan must be performed to confirm the diagnosis.

## History and Symptoms
The majority of patients with femoral hernia are asymptomatic. Most common symptom is swelling below the inguinal ligament. Emergent cases may present with signs of incarceration; abdominal pain, nausea, vomiting.

## Physical Examination
Patients with femoral hernia usually appear normal. Physical examination of patients with femoral hernia is usually remarkable for swelling or lump below the inguinal ligament. It is a difficult diagnosis and maybe impossible to differentiate from inguinal hernia. If incarceration is present, the swelling or lump maybe tender.

## Laboratory Findings
There are no diagnostic laboratory findings associated with femoral hernia.

## Imaging Findings

### X-ray
There are no x-ray findings associated with femoral hernia. However, an x-ray KUB may be helpful in the diagnosis of complications of femoral hernia, which include incarceration.

### CT scan
Although the diagnostic study of choice for femoral hernia is ultrasound, abdominal CT scan may be helpful in the diagnosis of femoral hernia. Findings on CT scan suggestive of femoral hernia include bowel dilation, mesangial thickening and bowel strangulation. Due to the radiation exposure and high cost it is not used a s first line diagnostic tool. In emergent cases that are difficult to diagnose, abdominal CT scan can be used as a first line diagnostic tool.

### MRI
The diagnostic study of choice for femoral hernia is ultrasonography, but abdominal MRI may be helpful in the diagnosis of femoral hernia. It provides the best anatomic detail, helps differentiate inguinal hernia from femoral hernia and has a sensitivity and specificity greater than 95%. Due to the high cost and lack of uniform availability it is not used as the diagnostic study of choice.

### Ultrasound
Ultrasound may be helpful in the diagnosis of femoral hernia. Findings on an ultrasound suggestive of femoral hernia include thickening and edema of the intestinal wall, slightly echogenic, long strip shaped omentum in the hernia sac.

# Treatment

## Medical Therapy
The definitive therapy for femoral hernia is surgery. Medical therapy is given to patients in preparation for surgery and postoperatively to prevent complications. Patients with pre and post operative pain should be treated with NSAID as a baseline analgesia. Patients with strangulated femoral hernia should be given broad spectrum antibiotics that cover both aerobic and anaerobic gram negative organisms.

## Surgery
Surgery is the mainstay of treatment for femoral hernia. Immediate surgical intervention is indicated in cases of incarceration or strangulation. The two popular surgical techniques are McVay repair and Lichenstein mesh repair. There is increased morbidity and mortality with surgical intervention in cases of strangulation or incarceration but it is still indicated. McVay repair is recommended in cases of intestinal incarceration as there is increased risk of infection following mesh repair in such cases.

## Prevention

### Primary prevention
Effective measures for the primary prevention of femoral hernia include optimal weight management, avoidance of rapid weight loss, use of good body mechanics while lifting heavy objects.

### Secondary prevention
Effective measures for the secondary prevention of femoral hernia include avoiding activities that increase intra-abdominal pressure, preventing constipation and usage of monofilament stainless steel wire for suturing after surgical repair.