Adhesions are common after abdominal surgery and cause 60%–75% of small bowel obstructions [1]. Although adhesive small bowel obstruction (ASBO) is very common, there is no standard treatment procedure. The treatment plan is usually based on the clinical experience of the surgeon. Clinical improvement is observed in more than 70% of patients without surgical intervention [2]. Delays in surgical intervention are associated with increased mortality and morbidity and prolonged hospital stays. Studies have shown that there is more than a 60% increase in mortality if surgical intervention is delayed for more than 4 days [3]. This increased mortality is associated with small bowel ischemia, gangrene, bacterial translocation, and perforation. According to a recent guideline, indications for conservative treatment and surgical treatment were evaluated in patients with ASBO [2].

Despite all these guidelines, delays in the surgical treatment option and an increase in mortality can be observed. For this reason, it is valuable to detect ASBO patients who will undergo surgical treatment in the early period, at their emergency admissions. In this study, we aimed to develop a scoring system that would enable us to predict at emergency admission those ASBO patients requiring well-timed surgery.

The retrospective records of 100 patients who were hospitalized and followed up/treated for ASBO secondary to surgery in the General Surgery Clinic of Haydarpaşa Numune Education and Research Hospital (Istanbul) between 2011 and 2021 were reviewed. Institutional Review Board/Ethics Committee approval (No. 2021/KK/245) and Institute Chief Physician approval (No. 62977267-E.230) were received for this study from the Ethics Committee and Hospital Management of Haydarpaşa Numune Education and Research Hospital, University of Health Sciences. All patients over the age of 18 years who had undergone abdominal surgery, regardless of the reason for which they had been operated on before, were included in the study. Patients with first-diagnosed/relapsed cancer, strangulated primary-secondary hernias, closed-loop obstruction, ischemia, intraintestinal foreign body, bezoar and gallstone ileus cases were excluded from the study. The patients’ retrospective laboratory values, radiological numerical data, hospitalization/surgery/discharge time interval information, and clinical follow-up/observation findings were obtained from the internal official database (Health Information Systems, version 5.5) of the institution. The details of the parameters to be examined are listed as follows: age, sex (male/female), previous surgery indication (cancer/others), chemoradiotherapy (CRT) history, previous surgery type (laparoscopic/open/conversion) before ASBO attack, recent number of hospitalizations for ASBO, overall recent duration of stay for ASBO, history of surgery for ASBO, emergency admittance plasma biochemical laboratory measurements (WBC, CRP, albumin [Alb], sodium [Na+]), potassium, %neutrophil, total bilirubin, direct bilirubin, indirect bilirubin), emergency admittance standing direct abdominal X-ray radiograph (AXR) air-fluid level number, largest horizontal air-fluid level distance in AXR, emergency admittance CT scan application (the patients with CT exam who had taken oral water soluble contrast) and, if applied, small intestine largest diameter in horizontal section of admittance CT scan, free intraperitoneal fluid in CT scan (with or without), the day of first gas-stool discharge from the day of admittance, surgery applied or not for ASBO treatment, the day of surgery for ASBO following the day of hospitalization, choice for anastomosis and/or stoma. Experienced radiologists checked abdominal CT exams for free intraperitoneal fluid. If any amount of fluid was detected in abdominal CT, it was classified as the presence of free fluid. All blood values and imaging parameters are those of emergency admission.

Patients whose surgical decisions were found to comply with the Bologna guidelines were included in the study [2]. The most common reasons for surgery in patients undergoing surgery more than 72 hours after admission were failure to resolve ASBO, deteriorating clinical status, and altered imaging results. The patients were divided into 2 groups: operated and not operated. We compared these 2 groups. The cutoff points of the significant values were calculated.

Descriptive statistics of demographic, radiological, and clinical characteristics of the cases included in the study are given in Table 1.

Table 2 includes the comparisons made in terms of demographic and clinical characteristics, laboratory measurements, and radiological characteristics of the cases according to the group operated on for ASBO and the group not operated on for ASBO. Mean age, sex distribution, history of operation for cancer, history of CRT, distribution of operations before ASBO attack, number and duration of previous hospitalizations for ASBO, history of surgery for ASBO, admittance laboratory measurements (except CRP, Alb, and Na+), and radiological features (except for small intestine largest diameter in horizontal section of admittance CT scan) were not statistically significant between the operated group and the not operated group (P > 0.05). On the other hand, admittance CRP and the largest diameter of the small intestine in the horizontal section of the admittance CT scan were significantly higher (P = 0.006 and P = 0.007) and the admittance Alb and Na+ values were significantly lower (P < 0.001 and P = 0.031) in the operated group than in the not operated group. In addition, free intraperitoneal fluid in CT scans was detected at a higher rate in the operated group.

ASBO is one of the most common diseases of the small intestine. ASBO has been a great stressor for both emergency physicians and general surgeons for years. The duration of conservative management, decision for optimal surgical intervention time, decision between performing stoma or anastomosis, limits of bowel resection, perioperative-postoperative morbidity and mortality, duration of intensive care unit stay, and cost/effectiveness of all these factors are still debated. The incidence of this disease after abdominal surgeries is 2.4% [4]. Clinical outcomes in patients with ASBO often depend on the time of surgical intervention if surgery is needed, but it is difficult to identify patients quickly and accurately [5]. A 2013 study showed that delayed surgical intervention was associated with both prolonged hospital stays and increased mortality [3]. While the timing of surgery in patients with ASBO is quite valuable, we found a limited number of studies that would allow us to predict the need for surgery in emergency hospitalization of patients with ASBO when we searched the literature in detail [6].

The primary goals in patients with suspected ASBO are making the differential diagnosis of ASBO and other causes of small bowel obstruction, determining the need for emergency surgery and determining the complications that may occur [2]. Careful anamnesis should be taken when making differential diagnoses in these patients. Knowing whether the patient has a history of previous operations, a history of radiotherapy, and can provide details of the last defecation date, oral tolerance, and vomiting is important. It should not be overlooked that defecation may occur in patients presenting in the early period or with an incompletely obstructed small intestine. Physical examination findings may not be evident in the early period and may not be evident in elderly patients [7]. Regardless of how carefully the findings of peritonitis are evaluated in the physical examination, the sensitivity is below 50%, even in the examination of experienced clinicians [8]. When evaluating the patient, this sensitivity increases when laboratory and imaging techniques are combined with anamnesis and physical examination. The most valuable method for detecting ASBO is CT [9].

According to the current consensus, a surgical approach is not recommended in patients with ASBO if there is no evidence of bowel strangulation or ischemia and peritonitis [2]. In the nonsurgical approach, treatment includes stopping oral intake, follow-up, and gastrointestinal decompression with the aid of a nasogastric tube. Nearly 90% of these patients can be treated with decompression [3]. Despite this high treatment rate, the delay in patients requiring surgery causes serious increases in mortality and morbidity. This increased mortality and morbidity can be seen not only due to ischemic findings but also due to increased risk of aspiration pneumonia, electrolyte imbalance, and malnutrition [1011]. It is suggested that patients who do not have signs of peritonitis and do not worsen in their clinical follow-up can be observed for 72 hours [2]. Although nonoperative treatment options come to the fore in patients with ASBO, there are studies showing that early operation reduces the recurrence rate and costs [12].

For all these reasons, it is valuable to predict surgery in patients who have not yet developed signs of peritonitis. For this prediction, we considered the parameters, including CT and laboratory values, one by one. In many studies of small bowel obstruction, leukocyte count was found to be significant in predicting surgery. In these studies, the cutoff value for leukocytes was found to be 10 × 10/L [9] and above [1314]. In our study, although the leukocyte value was higher in the surgery group, similar to other studies, the difference was not statistically significant.

In animal experiments, it has been shown that CRP is increased due to bacterial translocation after ASBO [15]. In a human study, it was shown that a CRP value of 7.5 mg/L and above is useful in predicting surgery in patients with small bowel obstruction [13]. In our study, a CRP above 5.7 mg/L was significant in predicting the need for surgery. Another finding in our study; significant third-space losses were considered the cause of low Alb levels. It can be thought that vasoactive amines released after ASBO cause capillary damage and increased vascular permeability, resulting in plasma exudation. As a result, hypoalbuminemia followed by hyponatremia was expected. This difference was statistically significant for both Alb and Na+. O’Leary et al. [16] found a higher rate of hyponatremia in patients who would require surgery. Similarly, lower sodium levels were found in the patient group requiring surgery in our study. Although this difference was statistically significant, the mean sodium values of both patient groups were within the normal range. In the study of Eren et al. [17], there was no difference in sodium values between the surgical and nonsurgical patient groups, and the mean sodium values of the patients were within the normal range. Hypernatremia due to hypovolemia and hyponatremia due to sodium loss after vomiting can be expected in ASBO patients.

One of the most predictive values for the need for surgery in patients with ASBO is derived from CT scanning of the largest diameter of the horizontal section of the small intestine. In many studies, researchers have tried to estimate the need for surgery in patients with small bowel obstruction based only on CT data [91819]. In addition, there are studies stating that a difference of more than 50% between the diameters of the distal and proximal small bowel loops indicates severe small bowel obstruction and that caution should be exercised in terms of the need for surgery [20]. Based on CT data, parameters such as bowel-wall thickening, mesenteric edema, the largest diameter of the horizontal section of the small intestine, intestinal pneumatosis, and free intraperitoneal fluid are estimated. In our study, we found that the largest diameter of the small intestine in the horizontal section that was wider than 3.85 cm was statistically significant. Another CT finding was that the presence of substantial pelvic intraperitoneal free fluid was statistically significant. The reason for this was thought to be increased vascular permeability.

With this study, we aimed to determine the need for surgery in patients with ASBO in the early period. The area under the curve of the score obtained with these laboratory and radiological results was 0.86. While our scoring is useful in patients close to the lower and upper score limits, additional evaluations will be useful in patients at the borderline. In the light of all this information and based on this scoring system, we can say that earlier surgical intervention may be considered in patients with a score of 4 and above.

Our study has some limitations. The first is the small number of patients. Another limitation is that the study is retrospective, so substantial data about the patients are missing. Among the missing data were the daily amount of content from the nasogastric tube, sedimentation, and some laboratory inflammatory markers.

In conclusion, we think this study is valuable because it includes the most comprehensive parameters to predict the need for early surgery in ASBO cases. Since our scoring system is simple and applicable, it should be considered when evaluating surgical decisions in the early period in patients with ASBO. We think that it can prevent delays in operation in many patients. Prospective studies with a larger patient population are needed to contribute to the subject.