Abdominal Wall Case 1

Clinical History:

F40 with 2 years RLQ pain after an open abdominal hysterectomy performed for endometriosis (with surgical access via an old cesarean section scar). Pain described as ‘burning’ in quality, provoked by physical activity and getting slowly worse over time, with an unexplained bulge of the RLQ abdominal wall now also present.

Imaging:

REVEAL DIAGNOSIS

Diagnosis:

“ACNES” [abdominal cutaneous nerve entrapment syndrome] secondary to post-surgical scarring and with consequent muscle dysfunction.

Discussion:

On ultrasound examination, there was a small trigger zone to palpation located both directly over, and slightly superior to, the right lateral end of the old cesarean section scar (most pronounced to palpation while the abdominal muscles were actively contracted in early sit-up position) –> this corresponded on real-time scanning with localised fusiform swelling of at least 2 (arguably 3) branches of the T11 thoraco-abdominal nerve at the entrance to rectus sheath.  The related fascial plane of linea semilunaris showed associated hypertrophic post-surgical scarring, and the RLQ abdominal wall showed features of muscle dysfunction resulting in diffuse segmental eventration bulge when straining in supine position or spontaneously evident at rest in standing position. Volume rendered CT images show (i) site of trigger point to palpation indicated by black asterisk, (ii) post-surgical scarring that obliterates the fascial outline of both lower right semilunar line and lower linea alba, and (iii) eventration bulge that can be appreciated on the angled-up view from below. Axial CT and MR images show localised marked thickening of scarring at semilunar line. Hi-res US images demonstrate focal swelling of T11 nerve branches at the right semilunar line [IO = Internal Oblique muscle; TA = Transversus Abdominis muscle; RA = Rectus Abdominis muscle]. Panoramic US images show normal abdominal wall contour at rest in supine position (top image) and RLQ eventration bulge at rest in standing position (bottom image).  There is no incisional or Spigelian hernia. With progressive weight gain and increasing nerve traction, neuropathic pain had worsened.