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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I.M. Daoud and K. Dunn
low hernia sac in which there is no herniation of intra-abdominal contents
[ 11 ]. In this study, they found that the incidence of a contralateral
“occult” inguinal hernia was 13 % when TAPP repair of a clinically
palpable inguinal hernia was performed. Of these, 8 % were true occult
hernias and 5 % were incipient. True occult hernias were repaired at the
time of exploration, and the incipient hernias were followed closely,
21 % of which became symptomatic, requiring additional surgery.
In a 2012 study by Garvey, it was found that of those with symptoms
suggestive of hernia, in the absence of clear physical exam findings,
33 % of patients who underwent CT examination were found to have an
occult inguinal hernia. This was then confirmed in the operating room
with 94 % accuracy. As discussed below, CT may not be the best imaging
modality, but this figure of 33 % serves to show the approximate
incidence of those with occult inguinal hernia who present with groin
pain [ 10 ].
In discussing occult hernia, women are an important population to
consider. Groin pain can be a common symptom in women with a differential
diagnosis similar to men, including urologic, gastrointestinal, or
musculoskeletal causes with the addition of gynecologic disorders [ 12 ].
The population of women with chronic pelvic pain is also important to
consider, as pelvic pain often includes the inguinal region [ 13 ]. Hernias
are often smaller in females, leading to an undetectable clinical impulse
on exam due to the absence of a processes vaginalis [ 14 ]. Of the approximately
20 million hernia repairs performed to date, only 6–8 % of these
have been performed in women. It has been suggested, however, that
occult hernias may be relatively common in women suffering from groin
pain, especially those who experience worsening of symptoms with
activity. Given the normal physical exam findings, these women can
often have a prolonged symptomatic period before a correct diagnosis of
groin hernia is achieved. As in men, it is important to consider and diagnose
a hernia before it presents as a surgical emergency [ 15 ].
Diagnosis The diagnosis of occult inguinal hernia can be tricky, as
there is often groin pain and suspicion of a hernia but no discernible
physical exam findings by general practitioner or surgeon. A metaanalysis
by Robinson et al. served to evaluate herniography, CT, MRI,
and ultrasound in finding occult inguinal hernias in those presenting
with groin pain. Herniography proved to be the most accurate modality,
with an overall sensitivity of 91 % and specificity of 83 %. Conversely,
CT showed a sensitivity of 80 % and specificity of 65 %. Ultrasound,
being largely operator dependent and with limited available data for this