**2.1. Incarceration and strangulation**

Incarceration is the process by which hernia contents are trapped within a hernial sac in which reducing them is not possible. This result in decreased venous and lymphatic flow thus edema of incarcerated tissue. As a result, normal gut flora start flourishing and gas accumulates due to bacterial fermentation. As the swelling enlarges, the arterial blood flow to the hernial sac contents is compromised leading to ischemia and tissue necrosis, which is known as hernia strangulation [8]. These two entities are complications of hernia itself and are associated with increased rates of mortality and morbidity. The risk of incarceration and subsequent strangulation tend to be higher in the first few months to years and decrease with time. Gallegos et al. [9] estimated the probability of incarceration to be around 2.8% at 3 months and 4.8% at 2 years, which might be partially due to weakening of the abdominal wall and decreased pressure on the sac and its contents [9, 10]. Some of the risk factors for incarceration and subsequent strangulation include advanced age at the time of presentation, femoral hernia, and recurrent hernia [8]. Morbidity and mortality are determined by many factors including the patient age, comorbidities, and duration of the strangulation, the longer the duration, the greater the strangulation risk. For the reasons mentioned above along with an increased risk of perforation, a strangulated hernia is considered a surgical emergency that mandates surgical intervention with possible bowel resection. If the strangulation lasts longer than 4–6 hours on average bowel resection may be warranted. In such scenarios, placement of prosthetic mesh is usually not advised, as there will be a higher chance of bacterial translocation and wound infection [11, 12].
