Incarcerated arcuate line hernia: rare clinical manifestation of a not so rare anatomical variation? A case report

S. Geuss, M. Koehli, S. Prica, J. Peltzer

Objective

Arcuate line hernia (ALH) is a rare diagnosis caused by herniation of abdominal structures in a peritoneal recess between the posterior lamina of the rectus sheath and the posterior surface of the rectus abdominis muscle ascending cranially from the arcuate line (AL). A PubMed search only revealed eight cases published until 2013. A recent series reviewing 315 abdominal computed tomography exams (CT) in asymptomatic patients reports an impressive 8.6% prevalence of ALH though lacking surgical confirmation. We present a case of ALH with omental incarceration treated laparoscopically in our department.

Results

Case description: a 68-year-old man presented to the emergency department with a painful bulge in the abdominal wall about 5 cm left and slightly caudally of the umbilicus. CT imaging of the region demonstrated a 3.1 x 0.9 cm protrusion of adipose tissue ascending 3 cm between the parietal peritoneum and the posterior aspect of the rectus abdominis muscle. Laboratory findings were normal. Laparoscopic exploration revealed bilateral peritoneal recess ascending from the AL between the rectus abdominis muscle and the posterior lamina of the rectus sheath. Lateralized to the left, a small portion of the omentum was incarcerated in the medial segment of the peritoneal recess accompanied by local peritoneal inflammation. The entrapped omental portion was reduced and subsequently resected. No hernia repair was performed. Postoperative recovery and 10 month follow-up were uneventful.

Conclusion

To our knowledge, this is the first photo documented case of incarcerated ALH. This pathology might be underdiagnosed because ALH tends to reduce spontaneously in the supine position used during CT examination and surgical exploration. ALH should be considered in patients presenting with chronic recurrent periumbilical pain. Combined clinical and radiological suspicion of an abdominal wall process at the level of the AL should prompt laparoscopic exploration. Furthermore, we recommend routine inspection of anterior abdominal wall for intraparietal AL recess during laparoscopic exploration for unexplained abdominal pain. We refrained from immediate hernia repair because of undetermined local inflammation. One proposed method is to reduce the peritoneal sac, then fixing the AL to the rectus muscle using spiral tackers. While closure of the peritoneal recess seems in general reasonable, consensus among surgeons is lacking due to the rarity of the condition.

Figure 1: Abdominal CT showing subperitoneal adipose tissue of the left anterior abdominal wall (arrow)
Figure 2: Intraoperative view of the peritoneal fold ascending from the left AL (arrow) after hernia reduction (*)