Incisional hernias can range in size from very small to large and complex ones and appear as a bulge by the area of a previous surgical scar. Nearly any prior abdominal operation can develop an incisional hernia, however the most frequent site is along incisions running down from the breastbone to the pubic area. These hernias may occur after large surgeries such as intestinal or vascular surgery, but also after an appendectomy or even through the small scar of a laparoscopy wound. Surgical repair of incisional hernias is usually recommended, as they can become a medical or surgical emergency.
An incisional hernia can be defined as complicated when the involved structures undergo worsening conditions. Particularly, the concerned structures may be described as follows:
Cutaneous: large and thin scars, cutaneous atrophy and eczemas, suppurative flogosis, fistulae.
Hernial sac: multiple sacs, fibrous septa, sac thickening and adhesions.
Visceral: chronic incarceration, obstruction, strangulation, ileum and colonic torsion with progressive damage up to gangrene; greater omentum involvement, mesenteritis and perivisceritis.
The frequency of complicated incisional hernias varies from 10 to 40%. The most frequent complications are incarceration, obstruction and strangulation .
There are two main factors for the pathogeneses of these complications: the hernial orifice rigidity and the presence of tenacious adhesions between the hernial sac and its content or between the sac and the surrounding tissues.
The formation of viscero-visceral and viscero-parietal bridles is the necessary condition for the production of strangulation: the intestinal loop contained into the sac is firstly affected by a transit alteration and later on by circulatory disturbance.
The strangulated intestinal tract rapidly goes towards congestion, edema and turgor caused by a disturbance of venous circulation which is followed by the formation of trasudate into the intestinal loop entrapped into the hernial sac; the intestinal wall goes towards progressive modifications up to necrosis and perforation. The omentum can be involved in the strangulation process; in such case the affected part adheres to the hernial sac and turns into a fibrous tissue. In case of strangulation, the symptoms will be those of a typical intestinal occlusion or subocclusion, depending on the elapsed time and the single material cause, although the synthomatology can sometimes be hard to define; for instance, in obese abdomens it is not easy to recognize the strangulation of small laparoceles.
The emergency surgical treatment for complicated incisional hernias, besides the problems given by the lack of intestinal preparation, shows a higher morbidity also due to the development of an acute respiratory failure; this is caused by the abdominal reduction of the herniated viscera which causes an increase of endoabdominal pressure pushing up the diaphragm .
Since the newly formed subcutaneous cavity resulting from the hernia reduction can be origin of haematic collections formation associated with a frequent necrosis of the cutaneous rims, we suggest to perform a cutaneous and subcutaneous resection in order to avoid both complications. Furthermore in all the patients we normally place one or two subcutaneous Jackson-Pratt suction drainages.
At the moment the most frequent treatment of voluminous incisional hernias is performed through the use of synthetic prosthesis, which allows the abdominal wall reconstruction according to the "tension free" technique.
The prosthesis is to be placed between the peritoneum and the posterior surface of the rectus abdominis muscles [8, 9] or between the posterior surface of the rectus abdominis muscles and their posterior sheath . In both cases the prosthesis apposition allows a strength discharge upon the abdominal wall circumference; moreover, the overlap of the muscle to the prosthesis (properitoneal technique) allows a wider distribution surface of tension strengths. In order to avoid a prosthesis dislocation, it is necessary to fix it to the abdominal wall by non-absorbable interrupted stitches (prolene). The prosthesis must be considerably wider than the parietal breach, so that the endoabdominal pressure might ease its adhesion to the abdominal wall. The anterior rectus muscles sheath is closed by a continuous non-absorbable suture. When it is not possible to suture the abdominal wall because of a massive tissutal loss, we place a PTFE prosthesis in contact with the viscera and we suture it to the muscle sheaths [11, 12]. PTFE avoids visceral adhesions, assuring this material to be used in properitoneal locations for voluminous incisional hernias when it is not possible to perform a direct peritoneal suture; it also lowers the infections incidence and causes only a weak foreign body reaction [13–19] (Appendix 1).
The described techniques performed in emergency do not show a higher incidence of complications (fistulisation, hematomas and wound dehiscence) compared to elective surgery [20, 21]; also according to our experience, the emergency treatment of complicated incisional hernias appears to be feasible, both in terms of post-operative complications and recurrences.