Is hernia to neck ratio important in umbilical and ventral hernia management?

Hernia-to-Neck Ratio in Umbilical and Ventral Hernia Management

The hernia-to-neck ratio (HNR) is critically important in umbilical and ventral hernia management as it directly predicts complication risk, with an HNR ≥2.5 strongly associated with emergent repair necessity, incarceration, and strangulation.

Understanding Hernia-to-Neck Ratio

The hernia-to-neck ratio (HNR) is calculated as:

• HNR = Maximum hernia sac size ÷ Maximum fascial defect size (neck size)
• Measurements are typically taken in the sagittal plane on imaging studies (CT, MRI, or ultrasound)

Clinical Significance of HNR

Recent research has established HNR as a powerful predictor of complications in umbilical and ventral hernias:

1. Predictive Value for Complications:

   • A 2016 study demonstrated that patients with complicated umbilical hernias had a significantly higher median HNR (3.33) compared to uncomplicated cases (1.76) 1
   • ROC curve analysis showed excellent predictive value with an area under the curve of 0.9038 1
   • An HNR cutoff of 2.5 provided 91% sensitivity and 84% specificity for predicting complications 1

2. Association with Emergent Repair:

   • A 2022 study confirmed that patients requiring emergent ventral hernia repair had significantly higher HNR (2.4) compared to those who did not require repair (1.7) 2
   • This study found smaller hernia neck size was significantly associated with emergent repair need, while hernia sac size alone was not predictive 2

Clinical Application and Recommendations

Risk Stratification

Patients with umbilical or ventral hernias with an HNR >2.5 should be offered surgical repair regardless of symptoms due to the high risk of complications. 1

Surgical Decision-Making

When evaluating patients with umbilical or ventral hernias:

1. Calculate HNR using appropriate imaging

2. Prioritize repair for:

   • Symptomatic hernias
   • Asymptomatic hernias with HNR >2.5
   • Hernias with defects >1 cm (as per guidelines) 3

3. Surgical approach considerations:

   • Mesh repair is recommended for most umbilical hernias, even small ones, as it significantly reduces recurrence rates 4, 5
   • For defects <1 cm, suture repair may be considered, though this remains controversial 3
   • Preperitoneal mesh placement with 3 cm overlap is recommended by guidelines, though registry data shows this is underutilized in practice 3

Pitfalls and Caveats

1. Overreliance on defect size alone:

   • Current practice often focuses only on hernia defect size, ignoring the critical HNR parameter
   • Registry data shows 75% of small (<2 cm) umbilical hernias are still treated with suture repair despite higher recurrence rates 3

2. Surgical technique selection:

   • Despite guideline recommendations, preperitoneal mesh placement is used in only 1.8% of small umbilical hernia repairs 3
   • This may contribute to higher rates of pain and recurrence observed in registry data

3. Special populations:

   • In overweight/obese patients, laparoscopic approaches like TAPP may allow placement of larger mesh with less risk of surgical site infection 6
   • HNR may be particularly important in these patients who have higher baseline complication risks

Conclusion for Clinical Practice

When evaluating umbilical and ventral hernias, calculating the HNR should become standard practice alongside measuring defect size. An HNR >2.5 should trigger surgical intervention even in asymptomatic patients due to the high risk of complications. Mesh repair techniques should be favored over suture repair for most umbilical hernias to reduce recurrence risk, with appropriate technique selection based on patient factors and hernia characteristics.