Outcomes of Emergency Abdominal Wall Hernia Repair: Experience Over a Decade

Background Abdominal wall hernias are a common surgical entity encountered by the general surgeon. Approximately 10% of abdominal wall hernia patients require emergency surgery. However, these surgeries are associated with a high rate of postoperative morbidity and mortality. This study aimed to analyze the morbidity and mortality in patients undergoing emergency abdominal wall hernia repair and to determine the factors associated with surgical site infection (SSI) and recurrence in these patients attending a tertiary care hospital in south India. Methodology Our study was a single-centered, 10-year retrospective and a one-year prospective study conducted in a tertiary care center in India. All patients who underwent emergency abdominal wall hernia repair between April 2009 and May 2020 were included. Patients’ demographic details, comorbidities, intraoperative findings, 30-day surgical outcomes including SSI, and recurrence were studied. Results Out of 383 patients in our study, 63.9% had an inguinal hernia, and 54% of the patients underwent tissue repair. SSI was the most common morbidity (21.9%). Postoperative sepsis was the only independent factor associated with perioperative mortality according to the logistic regression analysis (odds ratio = 22.73, p = 0.022). Conclusions Tissue repair for emergency hernia surgery has better outcomes than mesh repair in clean-contaminated cases.


Introduction
Abdominal wall hernias are a common surgical entity encountered by the general surgeon. Abdominal wall hernias are broadly classified as groin hernias (inguinal, femoral, and obturator hernias) and ventral hernias (epigastric, umbilical, paraumbilical, Spigelian, and incisional). Approximately 10% of the patients with abdominal wall hernia require surgery in an emergency setting [1]. However, these surgeries are associated with a significant postoperative complication rate and poor prognosis compared to their elective counterparts [2].
The rates of surgical site infection (SSI), readmissions, and re-exploration are higher in emergency repair due to more frequent acute presentation with advanced comorbidities, including morbid obesity and poorly controlled diabetes. In addition to the comorbidities, patients' general condition at presentation can pose further challenges. These challenges may include bowel obstruction causing acute inflammatory response leading to metabolic derangements, bowel ischemia or necrosis, and peritonitis following contamination [3]. All these can result in bacterial translocation, which decreases the threshold for infection. The use of mesh in an emergency surgery is still controversial despite the proven advantage in elective cases for its low hernia recurrence rates [4]. In the suboptimal setting, performing advanced techniques such as laparoscopy and component separation could be either less effective, or its role has not been well established in acute settings [2].
This study aimed to analyze the morbidity and mortality in patients undergoing emergency abdominal wall hernia repair retrospectively for 10 years and prospectively for one year. The outcome in patients undergoing emergency repair for abdominal wall hernia, the factors associated with complications such as SSI, and Demographic data of the study population revealed that the median age was 55 (IQR = 45-65) years for both genders. The majority of the study population were males (males: female = 2.5:1). The median weight of the study population was 60 (IQR = 50-70) kg in both males and females. The most common comorbidity seen in our patients was hypertension (22.5%), followed by diabetes (11.5%). About 21.4% of the patients were immunocompromised with diabetes mellitus, bronchial asthma, and history of cancer or steroid use. A history of abdominal surgery was present in 22.7% of patients. Patients with higher incidence of comorbidities such as diabetes mellitus, coronary artery disease, chronic liver disease, and immunocompromised state underwent tissue repair more commonly than mesh repair. Tissue repair was done using interrupted 2-0 polyglactin or polypropylene sutures. Mesh repair was done with polypropylene mesh fixed using interrupted polypropylene stitches. The two groups did not differ in the history of abdominal surgeries or ventral hernia repairs ( Table 1)    Intraoperatively, drains were placed in 29.5% of the patients. Most patients with a drain belonged to the tissue repair group when compared to the mesh repair group (p = 0.03). The median duration of surgery was significantly longer in the tissue repair group [120 (IQR = 90-150) minutes] when compared to the mesh group [105 (IQR = 60-120) minutes] (p = 0.029).
In the postoperative period, the most common complication was SSI (21.9%), followed by pulmonary complications (11.7%) and urinary tract infections (3.4%). Between the two groups, patients in the mesh repair group had a significantly lower incidence of SSI (T = 53, M = 30; p = 0.033). Patients in the tissue repair group developed postoperative sepsis more commonly than those in the mesh repair group (T = 4.3%, M = 0.6%; p = 0.024). Patients in the tissue repair group required prolonged ICU stay and hospital stay when compared to those in the mesh repair group, the difference of which was statistically significant. A total of 10 patients, five in each group, underwent re-exploration in the postoperative period ( Table 4).    Mortality was present in six (1.6%) patients in our study population. There was no significant difference in mortality rate between the tissue and mesh repair groups (1.9% vs. 1.1%; p = 0.528). One patient in the mesh group had acute myeloid leukemia and expired in the postoperative period because of medical complications rather than surgical complications. All four mortalities in the tissue repair group and one in the mesh repair group developed postoperative sepsis.

Tissue repair group (n = 207) Mesh group (n = 176) Total (n = 383) P-value *
The factors associated with postoperative SSI, in patients who underwent emergency abdominal wall hernia, by univariate analysis, were diabetes mellitus, past abdominal surgery, presence of peritonitis and ascites, bowel resection, surgery duration exceeding two hours, and CDC wound class I and IV. According to multivariate analysis, patients who underwent surgery for more than two hours had 2.  The overall recurrence rate of hernia in our study was 3.6%. Recurrence rate was more in the mesh group  We could follow 165 patients to study the recurrence pattern. The flat curves indicate a low rate of recurrence of hernias. Though recurrence was more in the mesh repair group, it was not significant (p = 0.786).

Discussion
In our study, inguinal hernia was the most commonly encountered entity requiring emergency hernia repair. About 245 (63.9%) patients had an inguinal hernia of which 225 (91.8%) were seen in males, which was similar to the survey conducted by Venara et al., where 65.1% had inguinal hernia [7].
In women, the most common type of hernia identified in our study was incisional hernia (55.6%). The higher incidence of incisional hernia in women could be due to obstetric surgical history with obesity and lax abdomen post-pregnancy. Improper emergency settings for cesarean section surgeries along with a higher incidence of anemia and malnutrition in developing countries can amount to an increased risk of developing incisional hernia in women [8].
In our study, only three patients had a femoral hernia (0.8%), and all three presented with intestinal obstruction. In a nationwide register-based study, where 46,717 groin hernia repairs were studied, the incidence of femoral hernia repair was 3%. In one of the Indian studies by Sulaiman et al., four out of 157 patients had a femoral hernia (2.5%) [9]. The risk factors for the development of femoral hernia include female gender, multiple pregnancies, increased intra-abdominal pressure like chronic constipation, and increasing age.
Around 57% of our study population had one or more comorbidities, which increased to 77% in patients over 65 years of age. Patients with comorbidities underwent tissue repair more commonly in our study (T = 68.4%, M = 31.6%). Haskins et al., in a retrospective study, investigated 2,449 patients with a ventral hernia and found that patients with diabetes mellitus underwent tissue repair more commonly (p = 0.02) [10].
Patients with clean surgical wounds underwent mesh repair more frequently (M = 126, T = 89), whereas patients with clean-contaminated (T = 77, M = 45), contaminated (T = 23, M = 3), and dirty wounds (T = 18, M = 1) underwent tissue repair predominantly. In the literature, evidence shows that patients undergoing mesh repair with a clean-contaminated or contaminated surgical field have an increased incidence of SSI compared to patients with a clean surgical area [11]. The World Society of Emergency Surgery (WSES) 2017 update advised mesh use in clean-contaminated cases because bowel strangulation or the need for bowel resection in the absence of contamination did not increase the chance of SSI [4]. In our study, we placed mesh in 45 patients out of the 122 patients who had a clean-contaminated surgical field. Mesh placement was mainly influenced by the operating surgeons' decision intraoperatively to avoid mesh infection. Bessa et al. studied 234 patients who underwent emergency ventral hernia repair and noted that the only limitation for mesh use was gross contamination of the surgical field [12].
In our study, the duration of surgery was significantly higher in the tissue repair group. Similar findings were observed in the meta-analysis by Grant et al., where the time taken to perform mesh repair was shorter than other non-mesh repairs [13]. We attributed the longer surgery duration in the tissue repair group to patients with obstruction or strangulation. These patients warranted hyper-oxygenation and warm mops for either congested, pre, or patchy gangrenous bowel, which could have potentially increased the intraoperative time. Moreover, patients who had gangrenous bowel had to undergo resection, which prolonged the surgery duration overall.
Derici et al., in their study on incarcerated abdominal wall hernia patients, noticed that strangulation was present in 42.9% of their study population [14]. Similar research done by Emile et al. had 57.4% of patients with bowel strangulation [15]. In our study, 96 (25.1%) patients presented to the emergency with strangulation, and 79.2% of them underwent tissue repair. Compared to these studies, where only incarcerated ventral hernias were included, our study also evaluated patients with uncomplicated hernias done in the emergency.
Bessa et al., in a 10-year retrospective study on emergency management of complicated groin hernias with mesh, concluded that it was safe to use prosthetic mesh in patients presenting with strangulation and incarceration [12]. In our research, surgeons preferred tissue repair to mesh placement in these patients, particularly in the elderly and those with comorbidities, because the chance of postoperative SSI was higher in our emergency setting (34.1%).
The small bowel was the most common content of the hernial sac in our study population (52.7%). Similarly, Tastaldi et al., in a 10-year retrospective study of emergency hernias, noted that a majority (55.3%) of their population had small bowel as hernial sac content [16].
In our study, 69 (18%) patients underwent bowel resection for complications such as gangrene, of whom only five patients underwent mesh repair. Derici et al., in their study, observed that 19.2% of their patients required bowel resection [14]. A systemic review by Hentati et al. did not recommend using mesh after bowel resection in incarcerated hernia patients [17]. The mesh placement was limited intraoperatively by factors such as contamination of the surgical field, resection of the bowel, and, more importantly, the heterogeneous surgical approach by the operating surgeons in our study.
In our study, 21.9% of the patients had SSIs. The incidence of SSI in tissue and mesh repair patients was 26.1% and 17%, respectively. In a study by Nieuwenhuizen et al., 203 patients underwent acute hernia repair, and the overall SSI rate was 12.3% [18]. In one of the Indian studies by Keswani et al., where 198 patients with abdominal wall hernia were analyzed, SSI was observed in 7% of elective surgeries and in almost 50% of emergency surgeries [19]. Emile et al. observed that the SSI rate was higher (7.5%) in the mesh group than in the tissue repair group (5.3%) [15]. Pandey et al. in their study noticed that the SSI rate was 26% in contaminated cases [20]. In our study, the prolonged surgery duration and contaminated surgical fields in tissue repair groups could explain the higher SSI rate.
WSES consensus suggests using mesh in clean-contaminated cases as it does not increase the postoperative wound morbidity [4]. In our study, eight out of 45 patients (17.8%) with clean-contaminated surgical fields who underwent mesh repair developed SSI whereas among the 77 patients who underwent tissue repair for clean-contaminated cases the SSI rate was 22.07%. Although the WSES consensus advocates mesh repair in clean-contaminated cases, more patients with clean-contaminated wounds underwent tissue repair than mesh repair (77 vs. 45) in our study. This could be because of the surgeon's decision based on intraoperative findings and the clinical condition of the patient.
The incidence of pulmonary complications was 11.7%, which was the second most common postoperative complication in the present series. The incidence was comparable to that noted by Martinez Serrano et al.
(9.6%) in their analyses of 402 patients who underwent emergency surgery for abdominal wall hernias [21]. The pulmonary complication rate in the study by Venara et al. was less (2.4%) when compared to our study as they had included only patients with pneumonia [7]. In our study, all patients with pneumonia and those with atelectasis, pleural effusion, and lower respiratory tract infections were also included.
The incidence of sepsis in the postoperative period was 2.6% in our study and it was 2.3% in the study by Tastaldi et al [16]. In our study, out of the 10 patients with sepsis, five patients had respiratory complications, and four patients had an anastomotic leak. One patient had both pulmonary complications and an anastomotic leak that required re-exploration. Out of the six patients with sepsis in the study by Tastaldi et al., four had pneumonia; one patient each had a bloodstream infection and urinary tract infection [16]. The respiratory complication was a common factor leading to sepsis in both the study populations.
Postoperative complications were more common among patients who underwent tissue repair than those who underwent mesh repair. In our study, 63.9%, 70.6%, and 90% of patients with SSI, postoperative ileus, and sepsis, respectively, underwent tissue repair. The hospital stay duration was significantly longer for the tissue repair group patients (eight vs. six days; p = 0.006). An increase in hospital stay duration in the tissue group may be due to increased postoperative complications compared to the mesh group.
Mortality was present in six (1.6%) patients in our study population. There was no significant difference in mortality rate between the tissue and mesh repair groups (1.9% vs. 1.1%; p = 0.53). One patient in the mesh group had acute myeloid leukemia and expired in the postoperative period because of medical complications rather than surgical complications. All four mortalities in the tissue repair group and one in the mesh repair group developed postoperative sepsis. Gul et al., in their study on 131 patients with incarcerated abdominal wall hernia, observed an overall mortality rate of 2.1%, but they noted a significant difference between mesh repair and tissue repair group (0% vs. 5.9%; p < 0.028) [22].
Emile et al. observed that patients with diabetes mellitus, previous hernia surgery, intestinal resection, and clean-contaminated wounds were associated with SSI [15]. Campbell et al. showed that prolonged surgery had increased SSI incidence postoperatively considering the complexity of the cases [23]. In our study, we found that increased surgery duration of more than two hours and a dirty surgical field (CDC class IV) were the two independent factors associated with SSI.
Our study showed that the presence of peritonitis, bowel resection, drain placement, pulmonary complication, and postoperative sepsis were the factors associated with perioperative mortality. Sepsis was found to be the only independent factor affecting mortality by univariate and multivariate analyses. Derici et al. investigated the factors associated with morbidity and mortality in incarcerated abdominal wall hernia patients. They found that among the various factors significant by univariate analyses, necrotic bowel was the single most important factor associated with morbidity and mortality by multivariate analyses. Both in our study and the study by Derici. et al. [14], gangrenous bowel requiring resection was an essential factor affecting the mortality in patients who had sepsis.
The overall hernia recurrence rate was 3.6% in our study. The hernia recurrence rate in patients who underwent mesh repair was 4.8%, whereas only 1.6% of the patients who underwent tissue repair had recurrence with no significant difference. Previous studies in the literature showed that the recurrence rate was more common in the tissue group than in the mesh group [17]. In our study, the unavailability of data from the past years and inadequate follow-up of patients could render an unreliable result on the recurrence rate.

Limitations
This study has its inherent limitations due to its retrospective nature, such as missing data and underestimated complications. Further, the treatment decisions were made by different surgeons, leading to a heterogeneous surgical treatment. As there were no existing guidelines for mesh use, our study intent was to provide a current institutional practice. A cautious interpretation of the various risk factors identified by univariate analysis for SSI and mortality is needed as there were many other confounding factors. There were insufficient data available on the long-term follow-up, so we could not conclude the association between mesh use and higher recurrence rates. Nonetheless, in the controversial field of hernia surgery, our institutional practices, along with a well-maintained and analyzed audit, will contribute to the already existing evidence in the literature, which is still considered difficult to obtain and scarce.

Conclusions
In our emergency hernia surgery practice, SSI was high and was the most common morbidity. Our study found that prolonged surgery and dirty surgical wounds were the main factors associated with SSI. The sole factor independently associated with mortality in our study was sepsis. Hence, mesh use, in a cleancontaminated wound should be decided by the operating surgeon on a case-by-case basis. Mesh use can be avoided when the risk of SSI is high as in elderly patients with uncontrolled comorbid conditions. Although the majority underwent tissue repair, the recurrence rate in them was low in our study. Therefore, we conclude that tissue repair for emergency hernia surgery has better outcomes than mesh repair. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue.

Conflicts of interest:
In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work.