Obturator Hernia: Symptoms, Types, Causes and Treatment

Obturator hernia is a rare but significant condition often overshadowed by more common causes of abdominal pain and bowel obstruction. Its elusive symptoms and subtle presentation frequently delay diagnosis, leading to high rates of complications. This article will guide you through the key aspects of obturator hernia—its symptoms, types, causes, and treatment—providing a clear, evidence-based overview for both clinicians and curious readers.

Symptoms of Obturator Hernia

Obturator hernia often presents a diagnostic challenge due to its nonspecific and subtle symptoms. Many patients do not exhibit classic signs, which leads to delays in recognition and treatment. Still, understanding its typical and atypical presentations can help sharpen clinical suspicion and facilitate earlier intervention.

Symptom	Description	Frequency/Notes	Source(s)
Abdominal pain	Common, may be generalized or localized	Often severe, can be intermittent	4,5,8
Vomiting	Frequent, associated with obstruction	Accompanies abdominal pain	4,5,9
Bowel obstruction	Inability to pass stool/gas, distension	Most common presentation (up to 90%)	2,4,6
Howship–Romberg sign	Pain radiating inner thigh/knee	Present in ~50% of cases	2,3,5,8
Palpable mass	Not common, difficult to detect	Rarely found	1,10
Hannington–Kiff sign	Absent thigh adductor reflex	Less frequently used/tested	3,6

Table 1: Key Symptoms of Obturator Hernia

Common Presentations

The majority of patients with obturator hernia develop symptoms of acute intestinal obstruction. This typically manifests as:

• Severe abdominal pain (sometimes intermittent at first)
• Abdominal distension
• Nausea and vomiting
• Inability to pass stool or gas

Such symptoms often prompt emergency evaluation. However, because obstruction can have many causes, obturator hernia is rarely the first consideration 2,4,5,6,9.

Characteristic Signs

Two physical signs are classically associated with obturator hernia, though neither is universally present:

• Howship–Romberg Sign: This is characterized by pain radiating from the inner thigh to the knee, exacerbated by thigh extension, abduction, or internal rotation. It is caused by compression of the obturator nerve by the hernia sac. This sign is present in approximately 50% of cases, but its absence does not rule out the diagnosis 2,3,5,8.
• Hannington–Kiff Sign: This refers to the absence of the thigh adductor reflex due to obturator nerve involvement. It is less commonly tested in practice and less frequently reported in the literature 3,6.

Atypical or Overlapping Symptoms

Some patients, especially the elderly, may present with vague complaints such as:

• General malaise
• Unexplained weight loss
• Symptoms mimicking hip or knee joint pathology (due to neuralgia)
• Nonspecific gastrointestinal upset

The lack of a palpable mass is also notable, as the hernia often lies deep beneath the pectineus muscle, making it difficult to detect on physical exam 1,10.

Diagnostic Challenges

The rarity and non-specific nature of its symptoms mean that obturator hernia is often diagnosed only after imaging—most commonly a CT scan—or during surgery for presumed bowel obstruction. Prompt recognition of the symptom constellation, particularly in thin, elderly women, is critical for early intervention and improved outcomes 2,4,6,13.

Types of Obturator Hernia

While obturator hernias are rare in general, they can manifest in different anatomical forms and stages, influencing both clinical presentation and treatment approaches.

Type/Stage	Description/Location	Frequency/Notes	Source(s)
Right-sided	Hernia through right obturator foramen	Slightly more common	2,4
Left-sided	Hernia through left obturator foramen	Less common	2,4
Bilateral	Both foramen affected	Rare (~10-25%)	2,4,12
Richter’s type	Only part of bowel wall herniates	May cause strangulation	7
Stages (I-III)	Progression from preperitoneal fat to full bowel herniation	Staging system	6,10

Table 2: Types and Stages of Obturator Hernia

Laterality: Right, Left, and Bilateral

Obturator hernias can occur on either side, but studies show a slight predominance for the right side, possibly due to the anatomic protection provided by the sigmoid colon on the left. Bilateral hernias, though rare, have been documented and may complicate diagnosis and repair 2,4,12.

• Right-sided: Most frequently observed, particularly in elderly women 2,4.
• Left-sided: Less common, but still significant 2,4.
• Bilateral: Occur in up to 10-25% of cases, and may coexist with other hernias such as femoral or inguinal 2,4,12.

Richter’s Type

A unique and particularly dangerous type is the Richter’s hernia, where only a portion of the bowel wall (usually the antimesenteric border) herniates through the defect. This can lead to strangulation and perforation without complete obstruction, making early recognition crucial 7.

Staging of Obturator Hernia

Obturator hernia formation can be conceptualized in three progressive stages 6,10:

1. Stage I: Preperitoneal fat and connective tissue enter the obturator canal.
2. Stage II: Formation of a peritoneal sac in the canal.
3. Stage III: Bowel or other abdominal contents herniate into the sac, potentially causing obstruction or strangulation.

Understanding these stages can aid in recognizing early, potentially reversible disease before life-threatening complications arise 6,10.

Causes of Obturator Hernia

Obturator hernia is multifactorial, with a combination of anatomical, physiological, and lifestyle factors predisposing certain populations—especially elderly women—to this elusive condition.

Factor	Description/Role	Main At-Risk Group	Source(s)
Female gender	Larger, more horizontal obturator canal	Elderly women (esp. multiparous)	1,5,13
Age	Elderly (typically >70 years)	Thin/underweight seniors	1,2,4
Low BMI	Loss of preperitoneal fat	Emaciated individuals	4,5,13
Multiparity	Repeated pregnancies weaken pelvic floor	Elderly, multiparous women	5,13
Chronic disease	Weakens tissue, increases intra-abdominal pressure	Elderly, comorbid patients	4,5
Chronic cough, constipation, ascites	Repeated pressure increases hernia risk	Elderly, chronic illness	5,6
Anatomical factors	Large obturator foramen, patulous canal	Predominantly in women	1,6

Table 3: Key Causes and Risk Factors for Obturator Hernia

Anatomical and Gender Predisposition

Obturator hernias almost exclusively affect elderly women. The obturator canal in women is larger and more horizontal, increasing the risk of herniation. In contrast, men have a narrower canal, providing some protection 1,5,13.

The Role of Age and Body Weight

• Age: Most cases occur in women over 70 years, with a mean age in the late seventies or older 1,2,4.
• Low Body Mass Index (BMI): Loss of fat around the obturator canal, due to chronic illness or aging, removes the natural barrier that typically prevents herniation 4,5,13.

Multiparity and Chronic Disease

• Multiparity (having had multiple pregnancies) is a well-established risk factor, as repeated stretching and weakening of the pelvic floor structures can predispose to herniation 5,13.
• Chronic diseases—especially those causing malnutrition, cachexia, or decreased muscle mass—contribute further to tissue weakness 4,5.

Increased Intra-Abdominal Pressure

Conditions that chronically raise intra-abdominal pressure—such as chronic cough, constipation, or ascites—increase the likelihood of obturator hernia development in predisposed individuals 5,6.

Other Contributory Factors

• Previous surgery: While not as strong a risk factor, prior abdominal or pelvic surgery may alter anatomy or tissue resistance.
• Genetic/anatomical variations: Some individuals may have a congenitally wider obturator canal, increasing risk 1,6.

Treatment of Obturator Hernia

Effective management of obturator hernia hinges on timely diagnosis and prompt surgical intervention. Given its high risk of complications, delayed treatment can be catastrophic, particularly in vulnerable elderly populations.

Treatment Option	Approach/Details	Effectiveness/Notes	Source(s)
Surgery (mandatory)	Open or laparoscopic repair	Only definitive treatment	1,2,4,5
Laparoscopic repair	Minimally invasive, mesh/suture	Lower morbidity/mortality, faster recovery	2,4
Open repair	Laparotomy, often in emergencies	Still common, esp. with bowel necrosis	1,4,14
Mesh repair	Synthetic mesh to reinforce defect	Reduces recurrence, good for non-infected cases	2,12,13
Suture repair	Simple closure of hernia defect	For small defects or contaminated field	4,13
Bowel resection	If necrosis/strangulation present	Increases morbidity/mortality	4,14
Non-surgical	Supportive care only if inoperable	High mortality	14

Table 4: Main Treatments for Obturator Hernia

Surgical Management

Surgery is the only curative treatment for obturator hernia. The choice of technique depends on patient stability, timing of diagnosis, and the presence of complications such as bowel necrosis.

Open vs. Laparoscopic Repair

• Open repair (laparotomy) remains the standard in emergency settings, especially when bowel ischemia, necrosis, or perforation is suspected 1,4,14.
• Laparoscopic repair is increasingly favored in early, elective cases or when diagnosis is made before complications arise. It offers:
  • Lower perioperative morbidity and mortality
  • Shorter hospital stays
  • Faster recovery 2,4

Mesh vs. Suture Repair

• Mesh repair is preferred when there is no contamination (i.e., no perforation or infection), as it offers better reinforcement and lower recurrence rates 2,12,13.
• Suture repair is used in cases where infection is present or the defect is small. It remains effective but may carry a slightly higher risk of recurrence 4,13.

Bowel Resection

When the hernia has caused bowel strangulation, necrosis, or perforation, resection of the affected segment is mandatory. This significantly increases both the risk of complications and mortality, highlighting the importance of early diagnosis 4,14.

Non-Surgical Management

Non-surgical management is generally reserved for patients who are not surgical candidates due to extreme comorbidity or terminal illness. Outcomes in this group are poor, with high mortality rates 14.

Importance of Early Diagnosis

Prompt recognition and surgical intervention are critical. Delays lead to increased bowel compromise, need for resection, and higher postoperative morbidity and mortality. Use of CT imaging has dramatically improved preoperative diagnosis and facilitated earlier, safer repairs 1,2,4,11,14.

Conclusion

Obturator hernia is a rare but dangerous condition, notable for its subtle presentation and high risk of serious complications when diagnosis is delayed. Awareness and understanding of its key features can save lives—especially in the most vulnerable populations.

Key Takeaways:

• Symptoms are often nonspecific: Look for signs of bowel obstruction, especially in thin, elderly women, and remember the Howship–Romberg sign.
• Types vary: Most are right-sided, but left and bilateral hernias occur; Richter’s type can be especially insidious.
• Risk factors are clear: Elderly, emaciated, multiparous women with chronic disease and increased intra-abdominal pressure are most at risk.
• CT scan is the gold standard for diagnosis: It allows for earlier and more accurate detection.
• Surgical repair is mandatory: Laparoscopic mesh repair is preferred when possible, but open repair is often needed in emergencies. Early intervention improves outcomes dramatically.

Raising clinical suspicion and acting swiftly can make the difference between a full recovery and a life-threatening complication in patients with obturator hernia.