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

19 Radiologic Evaluation for Postoperative Groin Pain
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Fig. 19.7. Axial and coronal MR neurogram images. Mesh is present within the
right inguinal canal ( white arrow ), its inferior border in contact with the ilioinguinal
nerve. An ilioinguinal neuroma ( curved white arrows ) has formed as a
result, and is found directly below the patient’s pain as indicated by the skin
fiducial marker ( large white arrow ).
internal inguinal ring and follows the spermatic cord/round ligament
into the scrotum/labia majora; and the femoral branch of the genitofemoral
nerve passes under the inguinal ligament alongside the external
iliac artery, innervating the femoral triangle.
Whether directly identified or merely implied by the course of the
mesh’s edge, the presence of sutures, tacks, or staples along the expected
path of these nerves should raise the suspicion of neuropathic etiology for
chronic post- herniorrhaphy pain. Entrapment, perineural fibrosis, and
neuroma are all readily apparent on MR, presenting as T2 hyperintensity
within the affected nerve (Fig. 19.7 ). MR neurograms are specifically protocoled
non-contrast MR images that allow for high-resolution evaluation
of the peripheral nervous system, but suffer from low signal-to-noise
ratios and should ideally be performed with a 3T magnet if available.
Other Complications
The two most common laparoscopic approaches to inguinal hernia
repair are known as TAPP (transabdominal preperitoneal) and TEP
(totally extraperitoneal), where TAPP perforates the peritoneum twice
and TEP remains outside the peritoneal cavity altogether (Fig. 19.8 ) [ 11 ,
12 ]. The TAPP approach in particular can predispose to scarring and
adhesion formation. CT is the preferred method of evaluation for postoperative
bowel obstruction, or trocar-associated bowel injury.
Inflammatory response to mesh may involve nearby pelvic structures
such as the bladder, resulting in intermittent nonspecific pain syndromes