Brian P. Jacob, David C. Chen, Bruce Ramshaw, Shirin Towfigh (eds.) - The SAGES Manual of Groin Pain-Springer International Publishing (2016)

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G.J. Mancini
Occult Hernia
Background An occult inguinal hernia is a true hernia of the
myopectineal orifice that is indicated by symptoms of groin pain,
worsened by activity, but not clinically apparent on physical exam or
basic imaging. This entity is a common clinical conundrum posed to
surgeons on nearly a daily basis. As an example, a middle-aged male is
sent by his primary care physician with left inguinal pain limiting his
daily work activities, but on exam no hernia can be found. This has been
traditionally labeled a groin sprain, and six weeks of lifting restrictions
and scheduled oral NSAIDs are recommended and prescribed. An occult
hernia is often termed athletic pubalgia, not because of its symptoms
without physical exam findings, but rather its presentation in the age and
demographics of the patient. If the prior example is changed to a healthy
18-year- old male soccer player who had left inguinal pain only while
playing, but not at rest, the label of sports hernia will be given. It is
estimated that occult hernia comprise 10–15 % of inguinal hernia disease,
and therefore all patients presenting with symptomatic inguinal region
pain should be considered to potentially have an occult hernia [ 1 ]. Occult
hernia can be a cord lipoma or indirect hernia sac that tracks along the
spermatic cord within the inguinal canal creating compression on the
ilioinguinal or genitofemoral nerves. Similarly, an occult hernia can be a
weak transversalis fascia allowing the floor of the inguinal canal to
bulge, compressing the nerves. An intact superficial inguinal ring will
limit the physician’s examination and thereby mask the true hernia,
making it difficult to diagnose.
Diagnosis Determining the presence of an occult hernia is difficult
based on physical exam alone. Clinical suspicion begins with a thorough
review of the patient’s duration, location, and triggers of the pain symptoms.
Up to one-third of patients with groin pain will have occult hernia
as the pathologic cause of their symptoms. Patients with occult hernia
often have physical triggers of pain that can be provoked by a position
change such as bending over or increase of intra- abdominal pressure
such as Valsalva maneuver.
Imaging is an important adjunct to assist the identification of an
occult hernia. There are several different imaging modalities with each
having their relative strengths and weaknesses. Ultrasound is a low-cost
and low-risk diagnostic imaging test. For occult hernia, the sensitivity
and predictive values are greatly dependent on the ultrasound technologist’s
expertise and the patient position during the exam. Performing the
ultrasound exam while the patient is standing and performing a Valsalva