**4.4. Mesh erosion\migration**

Mesh migration or erosion may occur after femoral or inguinal hernias and depends on the extent of the symptoms; hence mesh removal might be advised. Mesh migration can be categorized into primary and secondary. Primary, also known as mechanical, is when the mesh dislodges along the path with least resistance as a result of inadequate fixation or external forces. While secondary, is the slow movement of the mesh through nearby anatomical structures due to body response to a foreign body. The result is an erosion of adjacent structures such as the urinary bladder leading to urinary tract infections or hematuria, bowel injury and subsequent fistula formation, and spermatic cord erosion causing vessel obstruction [45, 46].

Ott et al. [47] reported a case of late intestinal fistula formation as a consequence of an incisional hernia repair using an inter-peritoneal mesh. Animal studies showed that micro-erosions and mesh migration and consequent fistulae formation is decreased when mesh covered with biological material such as collagen [48]. In addition, Leber [49] reported a higher incidence entero-cutaneous fistula formation with the use of Mersilene mesh.
