Page 14 - Prevention and Treatment of Incisional Hernia- New Techniques and Materials

Chapter 1
As far back as 1901, Eads recognized the high frequency of IH, and stated in the Annals of Surgery: “The occurrence of ventral hernia as a sequence of abdominal section is so common that it should command our thoughtful consideration”(16). Since then, extensive research on the aetiology and risk factors of abdominal wall hernias has been performed. During the 20th century, it was discovered that pathologic changes in connective tissue may render certain individuals particularly liable to hernia – a condition described as “herniosis”(17). The role of genetics, the collagen type 1 and 3 ratio, and matrix metalloproteinases in herniosis has been uncovered(18).
However, it is not only the patient characteristics and genetics that impair wound-healing that make patients susceptible to the development of IH. The e ect of increased intra-abdominal pressure on the development and aggravation of abdominal wall hernias has also been recognized. In the last century, Jenkins focussed his research on a mechanical approach to IH development(19). During the postoperative period, abdominal distension can present as a problem, due, for example, to paralytic ileus. Almost all patients experience some period of paralysis, and approximately 40% of patients experience a paralytic ileus lasting more than ve days(20). Jenkins’ measurements showed that abdominal girth and the xiphoid-pubic distance may lengthen by up to 30% during abdominal distension. An adequate reserve of suture length in the wound is therefore necessary to allow for this lengthening to occur, to ensure the minimal resulting rise in tension between the sutures and the tissues. Jenkins calculated a suture length to wound length (SL:WL) ratio of 4:1 to be su cient for a patient with postoperative abdominal distension and a 30% increase in wound length(19). Suturing the fascia of a midline laparotomy with a SL:WL of 4:1 reduces the tension on the suture, and, in turn, the risk of suture pull-out through the fascia. Applying an adequate SL:WL ratio signi cantly lowers the risk of IH(21, 22). In daily practice, most surgeons perform a continuous suture technique with slowly-absorbable suture material to close a midline laparotomy.
Conditions that impair wound healing and make patients susceptible to the development of IH include: wound infection, diabetes mellitus, obesity, immunosuppressive drugs, and smoking(4, 12, 23). Taking into account patient factors and surgical technique, the incidence of IH at the present time remains high, and prevention seems, therefore, of uttermost importance.
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