Many patients are referred to our practice after an ultrasound report states that they have an inguinal hernia. While ultrasound can be a useful diagnostic tool in selected situations, it is important to understand that a positive ultrasound does not necessarily mean a patient has a clinically significant inguinal hernia.
In our practice, we commonly evaluate patients who have been told they have a hernia based on an ultrasound, yet a careful physical examination reveals no evidence of an inguinal hernia. This situation is more common than many patients realize and highlights why imaging should always be interpreted in the context of an experienced clinical evaluation.
The Physical Examination Remains the Gold Standard
For most patients with a typical inguinal hernia, diagnosis can be made by an experienced hernia surgeon through a careful history and physical examination. International groin hernia guidelines emphasize that imaging is not routinely necessary when the diagnosis is evident on clinical examination. A hernia is ultimately a clinical diagnosis, not simply an imaging finding.
Ultrasound Has a Meaningful False-Positive Rate
Ultrasound is highly operator-dependent and can mistake normal tissue, preperitoneal fat, spermatic cord lipomas, or tissue movement during a Valsalva maneuver for a hernia.
A 2022 study published in Insights into Imaging evaluated 175 consecutive patients who underwent surgery after receiving a positive ultrasound diagnosis of an inguinal hernia. Surgical findings served as the gold standard. The authors found that 159 patients had a true hernia while 16 did not, representing a false-positive rate of approximately 9% (nearly 1 in 11 positive ultrasounds). Among patients without a visible or palpable groin bulge, the false-positive rate increased to approximately 15%.
Imaging Is Even Less Reliable for Occult Hernias
A study published in JAMA Surgery comparing ultrasound, CT, and MRI in patients with suspected occult inguinal hernias found ultrasound to be considerably less accurate than MRI and concluded that MRI should be the preferred imaging study when clinical suspicion remains despite an inconclusive examination.
Why This Matters
A report describing a 'small fat-containing inguinal hernia' may sound definitive, but imaging findings do not always correlate with a patient's symptoms or with what is actually found during surgery. Relying solely on an ultrasound may lead to unnecessary referrals, unnecessary anxiety, and in some cases, unnecessary surgery. Surgical decisions should always be based on a detailed history, a careful physical examination, the patient's symptoms, and imaging only when it supports the clinical picture.
Our Philosophy
At our practice, we believe patients deserve an accurate diagnosis before considering surgery. While ultrasound can be a helpful adjunct in selected cases, it should never replace a thorough examination performed by an experienced hernia surgeon. Our goal is not simply to operate on an imaging report, but to ensure that surgery is recommended only when the diagnosis is clear and the patient is likely to benefit.
- Marc Zare
References
- Ridha H, de Vries RPH, Nijholt IM, et al. Positive Predictive Value of Ultrasound in Correctly Identifying an Inguinal Hernia: A Single-Centered Retrospective Pilot Study. Insights into Imaging. 2022.
- Robinson A, Light D, Nice C, Metcalfe M. Role of Imaging in the Diagnosis of Occult Hernias. JAMA Surgery. 2014.
- HerniaSurge Group. International Guidelines for Groin Hernia Management. Hernia. 2018.
