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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J.M. Miller et al.
includes a post-herniorrhaphy patient with significant pain who underwent
percutaneous biopsy of “bilateral inguinal masses” that were in
fact mesh Perfix TM plugs that were impressing upon the contents of the
inguinal canal, resulting in testicular venous congestion and chronic
pain. Most plugs are found within the inguinal canal with a cone appearance,
and conversion to a different shape (especially a narrow needlelike
one) may be indicative of abnormality, suggesting migration as an
etiology of groin pain. When properly positioned, sandwich mesh, such
as the Prolene TM Hernia System , should be seen on MR as a T1 dark
band superficial to the internal inguinal ring or direct fascial defect, with
a second layer positioned preperitoneally: the presence of fat between
the layers represents normal appearance.
When part or all of the implanted mesh material migrates or folds
into a circumscribed ball and produces mass effect on surrounding tissues,
it is referred to as a meshoma and can result in significant pain and
discomfort [ 7 ]. Similar inflammatory response to mesh materials without
apparent deformity is called mesh reaction, and can be characterized
by soft tissue edema. Mild tissue reaction has been reported even years
after herniorrhaphy without evidence of infection [ 8 ]. The identification
of both pathologies has led to the development of at least partially bioabsorbable
mesh materials in an effort to limit tissue response, although
these materials may predispose to recurrent hernia [ 9 ]. This is because
bioabsorbable devices consist of decreased amounts of synthetic materials
that are instead interlaced with collagen for structural integrity. As
that collagen is broken down over time, less mesh is left in place.
Totally synthetic-free “biologic” mesh is also finding clinical applications
and would be expected to be indistinguishable on imaging from
surrounding tissues without gross pathology present.
Neurologic Complications
The iliohypogastric, ilioinguinal, and genitofemoral nerves all traverse
the areas involved in surgical repair of inguinal hernia, and as such
are predisposed to injury during herniorrhaphy, depending on the technique
used. As a quick review of the relevant neuroanatomy: [ 10 ] the
iliohypogastric nerve runs deep to the internal oblique muscle, its cutaneous
branch emerging about a centimeter above the external ring of the
inguinal canal; the ilioinguinal nerve traverses the inguinal canal and
supplies the tissues around and overlying the external inguinal ring; the
genital branch of the genitofemoral nerve enters the inguinal canal at the