Society: SSAT

Background
An incisional hernia (IH) is one of the most frequent complications after a laparotomy, affecting between 10 -20% of patients. This incidence increases substantially in patients with comorbidities such as obesity, smoking, diabetes, immunosuppression and certain conditions such as diverticulitis or abdominal aortic aneurysm. The molecular basis for this variability is poorly understood but is now being addressed by many investigators. In this study, we looked at the role of molecular proteins called cytokines in the improper wound healing that leads to IH. We examined the cytokines present within muscle tissues of IH. We hypothesize that increased proinflammatory cytokines and decreased anti-inflammatory cytokines lead to impaired wound healing and the development of IH. Understanding the molecular microenvironment of muscle tissue in IH is important because these cytokines serve as potential therapeutic targets for improving the body’s repair response to ultimately decrease susceptibility to IH.

Experimental Design
Samples of muscle, adipose, and fascia were collected during IH repair. Muscle tissue was separated, processed, transversely sectioned onto glass slides, and stained using immunofluorescent tagged antibodies that bind leptin, adiponectin, TNF-α, and IL-6. The immunofluorescent findings were compared with the results of RTPCR quantification of the specific genes studied within the same tissues. The stained sections were scanned and analyzed using ImageJ software to quantify the expression of each cytokine in the samples compared to controls. Control muscle tissue was obtained from brain dead organ donors without prior abdominal surgery.

Results
Results of our immunofluorescence analysis demonstrate that proinflammatory cytokines leptin, TNF-α, and IL-6 were expressed in higher quantities while anti-inflammatory cytokine adiponectin was expressed in lower quantity in IH tissue compared to control tissue. The results of RTPCR analysis also showed significantly increased gene expression of leptin, TNF-α, and IL-6. However, adiponectin was significantly increased in patients compared to controls which was not consistent with our immunofluorescence analysis. This discrepancy may be due to a regulatory mechanism that affects the translation of mRNA (RTPCR) to protein (immunofluorescence) in a predominantly proinflammatory environment.

Conclusion
We found a significantly increased expression of proinflammatory cytokines leptin, TNF-α, and IL-6 in muscles tissue and decreased expression of anti-inflammatory cytokine adiponectin from IH patients when compared to controls. This supports the notion that an imbalance of cytokines with a predominance of proinflammatory cytokines impairs the wound healing process and may be a treatable target to prevent postoperative IH.

Background:

Inter-hospital transfers mark a critical decision point in the patient care continuum. Despite evidence that patients transferred between healthcare systems are more complex and experience greater morbidity and mortality, there are no available tools to correctly triage surgical patients based on their disease acuity. We hypothesized that readily available, low complexity patient parameters at the time of transfer could predict mortality after transfer.

Methods:

All patients transferred into general and colorectal surgery services at a quaternary care hospital between January-2016 and August-2022 were included. Demographics, laboratory values, vital signs, intensive care unit (ICU) admission, and vasopressor use were extracted from the medical record. Variables were chosen for easy availability, decreased variability, and feasible collection by trained non-physician transfer center personnel with nursing input from the transferring center. The primary outcome was admission-related mortality, defined as death during the admission or within 30 days post-discharge. Univariate differences were tested between the outcome groups. Logistic regression, penalized regression, gradient boosting regression, and deep neural network predictive models were trained on the training dataset and their performance was compared on the validation dataset.

Results:

A total of 4,664 adult transfers were included. Admission-related mortalities were 280 (6.0%): 142 (50.7%) occurred during the admission and 138 (49.3%) occurred in the 30-days after discharge. On univariate analysis, differences in all components of complete blood count, basic metabolic panel, and vital signs were statistically different between the two outcome groups. In addition, compared to survivors, patients who suffered mortality were more likely to be transferred from or into an ICU [153 (54.6%) vs. 758 (17.3%), P<0.001] and more likely to require vasopressor support [87 (31.1%) vs. 202 (4.6%), P<0.001]. While all variables were tested, only 12 commonly collected variables were included in the final model based on the penalized regression method. The model coefficients are numerated in Table 1. When validated, the final model achieved an area under the receiver operating characteristic curve, sensitivity, specificity, and accuracy of 0.846, 0.79, 0.72, and 0.72, respectively. After bias-correction, the Hosmer-Lemeshow C-statistic for the model was 8.22, P=0.412 indicating strong prediction and calibration.

Conclusion:

In an inter-hospital transfer setting, it is possible to predict the risk of mortality for general surgical patients based on readily available clinical parameters. Utilizing such a risk score could assist accepting hospitals in triaging patients to prioritize transfer acuity, improve resource allocation, and standardize care.

Table 1. Clinical patient variables predictive of mortality after inter-hospital transfer with corresponding coefficients at minimum Lambda and odds ratios.

Table 1. Clinical patient variables predictive of mortality after inter-hospital transfer with corresponding coefficients at minimum Lambda and odds ratios.

Background: Obesity is associated with an increased risk of ventral hernia (VH) development and recurrence rates after ventral hernia repair (VHR). The metabolic derangements caused by obesity can also lead to many postoperative complications. Therefore, it is a common practice to attempt weight loss before VHR. However, there is still no consensus on optimal preoperative management for obese patients with a ventral hernia. This study aims to perform a meta-analysis to evaluate the effect of preoperative weight optimization on VHR outcomes.
Methods: We performed a literature search of PubMed, Scopus and Cochrane Library databases to identify studies comparing obese patients who underwent surgical or non-surgical weight loss interventions before undergoing VHR to obese patients who underwent upfront VHR. Postoperative outcomes were assessed by means of pooled analysis and meta-analysis. Statistical analysis was performed using RevMan 5.4. Heterogeneity was assessed with I² statistics.
Results: 1,609 studies were screened and 13 were thoroughly reviewed. Five studies comprising 465 patients undergoing hernia repair surgery were included. No differences in hernia recurrence (OR 0.66; 95% CI 0.23-1.89; P=0.44; I²=20%), seroma (OR 0.70; 95% CI 0.25-1.95; P=0.50; I²=5%), hematoma (OR 2.00; 95% CI 0.5-7.94; P=0.45; I²=0%), surgical site infection (OR 1.96; 95% CI 0.52-7.40; P=0.32; I²=0%) and overall complication (OR 0.80; 95% CI 0.37-1.74; P=0.58; I²=40%) rates were noted when comparing patients who underwent a preoperative weight loss intervention (prehabilitation or bariatric surgery) versus those who did not. In the subgroup analysis of patients who underwent bariatric surgery, we found no difference in hernia recurrence (OR 0.64; 95% CI 0.12-3.33; P= 0.59; I²=41%) or overall complications (OR 1.14; 95% CI 0.36-3.64; P=0.82; I²=64%). In the subgroup analysis of patients who lost weight versus patients who did not, there was no significant difference in overall complication rates (OR 0.86; 95% CI 0.34-2.21; P=0.76; I²=55%).
Conclusions: We found similar hernia recurrence, seroma, hematoma and surgical site infection rates in patients who underwent preoperative weight optimization. These findings underline the need for prospective studies to define the optimal role of preoperative optimization and weight loss in obese patients undergoing ventral hernia repair.

Background: Total enterectomy (TE) is a rarely performed procedure. Re-establishment of bowel continuity, quality of life, and overall outcomes are important aspects to be considered in patients who might need a TE. We describe our experience with the operative and medical management of patients with "no gut syndrome”, with special interest on the effects of gastrointestinal (GI) reconstruction on the degree of parenteral nutritional (PN) dependency. Methods: We retrospectively reviewed 1005 adult patients who were referred to our center between January 2013 and October 2022. Results: Twenty-seven patients (2.7%) with a mean age of 41.7 years (range 17 to 66 years) underwent total enterectomy. In two patients the duodenum was also resected as part of original operation. Main indications for small bowel resection were vascular event (n = 11), and trauma (n = 8). Ten patients (38%) had reestablishment of GI gastrointestinal tract continuity after total enterectomy with duodenocolostomy (n = 9) or gastrocolostomy (n=1). Tube decompression (n=11) or ostomy creation (n=6) was used for foregut decompression in the remaining patients. Duodeno- or gastrocolonic anastomosis were at mid transverse colon (n=7), cecum (n=2) and hepatic flexure (n=1). There were no intraoperative or perioperative (< 30 days) deaths. All patients were on home parenteral nutrition (PN) infused over a 10- to 16- hour period. Average PN volume and calories were 2,600 mL/day (range 1,600 to 4,000) and 1,624 Kcal/day (range 1,125 to 2,320), respectively. Patients who underwent duodeno- or gastrocolonic anastomosis received smaller PN volume (33.2 vs 44.4 mL/kg/day). PN dependency index (PN intake/ basal energy expenditure %, mean±STD) was 116±18% in patients with tube decompression and ostomy and 94±20% in patients with colon in continuity (P < 0.05). Patients who underwent autologous reconstruction of their GI tract presented better short- and long- term survival (p <0.05). Seven patients underwent uneventful isolated small bowel and multivisceral transplantation with one- and three- year patient and graft survival of 100% and 85%. Another six patients are being evaluated or are already listed for visceral transplantation. Conclusion: Long-term survival can be achieved after total enterectomy in intestinal failure specialized centers. In addition, reestablishment of GI tract continuity after TE decreases the daily fluid and electrolyte requirements by approximately 25%. The addition of the colon in patients with no gut also results in a reduction in the parenteral energy requirements. This data reinforces the idea of the colon as an energy-salvaging organ even in patients with no gut.

Introduction: Higher perioperative volume during elective abdominal surgery leads to delayed return of bowel function in adults. Given the paucity of evidence in the neonatal population, we sought to evaluate the relationship between perioperative volume and return of bowel function in this population.
Methods: After IRB approval, a retrospective chart review (2016-2021) identified 70 neonates (0-52 weeks) who underwent an elective surgery with a bowel anastomosis. Patients were excluded (n=7) for sepsis at time of surgery, postoperative infection or anastomotic leak, surgery classified as emergent/urgent, need for parenteral nutrition at discharge, or missing data. Data collected included demographics (age, race, gender, weight at surgery), perioperative variables (volume administered (mL/kg) including blood products, type of surgery and anastomosis, narcotic use), and outcomes (time to start and reach goal enteral feeds, length of ICU and hospital stay, days on ventilator and TPN). Return of bowel function was defined as the start of enteral feeds in the neonatal population. Descriptive statistics and linear regression were performed, with p < 0.05 considered significant.
Results: 63 neonatal patients (65% male, 76% white, median age 6wks (IQR 23), median weight 4.04 kg (IQR 3.24) underwent elective surgery including bowel anastomosis (small bowel to small bowel (n=37), colon to colon/rectum (n=15), small bowel to colon/rectum (n=8), or other (n=3)). The median length of operation was 179 minutes (IQR 125). The median volume of intraoperative fluids was 38mL/kg (IQR 29) and a median perioperative (intraop + postop day (POD) 0-2) volume of 180 mL/kg (IQR 105). 61 patients (97%) received intraop narcotics (mean 1.3 +/- 1.3 morphine milliequivalents). Enteral nutrition was resumed at a median of 3 days postop (IQR 4) and goal feeds achieved at a median of 8 days postop (IQR 13). On multivariate analysis, the start of feeds was correlated with intraoperative volume (p<0.001), length of operation (p=0.001), but not weight at time of surgery (p=0.16) or narcotic use (p=0.3). The volume administered during surgery explains nearly 24% of the variation in the start of feeds with a slope of 0.1 (see figure).
Conclusions: The amount of intraoperative volume administered during elective abdominal surgery significantly impacted the start of feeds in neonates. In our series, for each 10 mL/kg of additional volume administered at surgery, the start of feeds was extended by 1 day.

Marissa Martinelli

Appearances