Small Bowel Obstruction and Ischemia

Prognostic factors to identify resolution of small bowel obstruction without need for operative management: systematic review

OBJECTIVES

To identify imaging, clinical, and laboratory variables potentially prognostic for surgical management of small bowel obstruction.

METHODS

Two researchers systematically reviewed indexed literature 2001-2021 inclusive for imaging, clinical, and laboratory variables potentially predictive of surgical management of small bowl obstruction and/or ischaemia at surgery, where performed. Risk of bias was assessed. Contingency tables for variables reported in at least 5 studies were extracted and meta-analysed to identify strong evidence of association with clinical outcomes, across studies.

RESULTS

Thirty-one studies were ultimately included, reporting 4638 patients (44 to 313 per study). 11 (35%) studies raised no risk of bias concerns. CT was the modality reported most (29 studies, 94%). Meta-analysis of 21 predictors identified 5 strongly associated with surgical intervention, 3 derived from CT (peritoneal free fluid, odds ratio [OR] 3.24, 95%CI 2.45 to 4.29; high grade obstruction, OR 3.58, 95%CI 2.46 to 5.20; mesenteric inflammation, OR 2.61, 95%CI 1.94 to 3.50; abdominal distension, OR 2.43, 95%CI 1.34 to 4.42; peritonism, OR 3.97, 95%CI 2.67 to 5.90) and one with conservative management (previous abdominopelvic surgery, OR 0.58, 95%CI 0.40 to 0.85). Meta-analysis of 10 predictors identified 3 strongly associated with ischaemia at surgery, 2 derived from CT (peritoneal free fluid, OR 3.49, 95%CI 2.28 to 5.35; bowel thickening, OR 3.26 95%CI 1.91 to 5.55; white cell count, OR 4.76, 95%CI 2.71 to 8.36).

CONCLUSIONS

Systematic review of patients with small bowel obstruction identified four imaging, three clinical, and one laboratory predictors associated strongly with surgical intervention and/or ischaemia at surgery.

CLINICAL RELEVANCE STATEMENT

Via systematic review and meta-analysis, we identified imaging, clinical, and laboratory predictors strongly associated with surgical management of small bowel obstruction and/or ischaemia. Multivariable model development to guide management should incorporate these since they display strong evidence of potential utility.

KEY POINTS

• While multivariable models incorporating clinical, laboratory, and imaging factors could predict surgical management of small bowel obstruction, none are used widely. • Via systematic review and meta-analysis we identified imaging, clinical, and laboratory variables strongly associated with surgical management and/or ischaemia at surgery. • Development of multivariable models to guide management should incorporate these predictors, notably CT scanning, since they display strong evidence of potential utility.

The target sign: a significant CT sign for predicting small-bowel ischemia and necrosis

OBJECTIVE

To investigate the correlation between changes in the thickness and density of diseased small-bowel wall and small-bowel ischemia and necrosis (SBN) on CT imaging when small-bowel obstruction (SBO) occurs.

METHODS

We retrospectively analyzed 186 patients with SBO in our hospital from March 2020 to June 2023. The patients were divided into simple SBO (control group) and SBN (case group) groups. We used logistic regression analysis, the chi-square test, and Fisher's exact test to analyze the correlation between the changes in the thickness and density of the diseased intestinal wall and the SBN. A receiver operating characteristic (ROC) curve was used to calculate the accuracy of the multivariate analysis.

RESULTS

Of the 186 patients with SBO, 98 (52.7%) had simple SBO, 88 (47.3%) had SBN, and the rate of SBN was 47.3% (88/186). Multivariate regression analysis revealed that six CT findings were significantly correlated with SBN (p < 0.05), namely, thickening of the diseased intestinal wall with the target sign (OR = 21.615), thinning of the diseased intestinal wall (OR = 48.106), increase in the diseased intestinal wall density (OR = 13.696), mesenteric effusion (OR = 21.635), decrease in the diseased intestinal wall enhancement on enhanced scanning (OR = 41.662), and increase in the diseased intestinal wall enhancement on enhanced scanning (OR = 15.488). The AUC of the multivariate analysis reached 0.987 (95% CI 0.974-0.999). Specifically, the target sign was easily recognizable on CT images and was a significant CT finding for predicting SBN.

CONCLUSION

We identified 6 CT findings that were significantly associated with SBN, and may be helpful for clinical treatment.

Abdominal Emergencies in Cancer Patients

Abdominal emergencies in cancer patients encompass a wide spectrum of oncologic conditions caused directly by malignancies, paraneoplastic syndromes, reactions to the chemotherapy or often represent the first clinical manifestation of an unknown malignancy. Not rarely, clinical symptoms are the tip of an iceberg. In this scenario, the radiologist is asked to exclude the cause responsible for the patient's symptoms, to suggest the best way to manage and to rule out the underlying malignancy. In this article, we discuss some of the most common abdominal oncological emergencies that may be encountered in an emergency department.

The EUPEMEN (EUropean PErioperative MEdical Networking) Protocol for Bowel Obstruction: Recommendations for Perioperative Care

Mechanical bowel obstruction is a common symptom for admission to emergency services, diagnosed annually in more than 300,000 patients in the States, from whom 51% will undergo emergency laparotomy. This condition is associated with serious morbidity and mortality, but it also causes a high financial burden due to long hospital stay. The EUPEMEN project aims to incorporate the expertise and clinical experience of national clinical specialists into development of perioperative rehabilitation protocols. Providing special recommendations for all aspects of patient perioperative care and the participation of diverse specialists, the EUPEMEN protocol for bowel obstruction, as presented in the current paper, aims to provide faster postoperative recovery and reduce length of hospital stay, postoperative morbidity and mortality rate.

Adhesive Small Bowel Obstruction: A Review

Adhesion is a leading cause of small bowel obstruction. Adhesive small bowel obstruction has significant challenges in diagnosis, treatment and prevention with considerable impact on morbidity and socioeconomic burden. Small bowel obstruction caused by adhesion or any other aetiology is clinically indistinguishable due to similar clinical presentation. Computed Tomography scans and water-soluble contrast studies are more specific in diagnosis and possess value in predicting the need for surgery. Surgical management is indicated only in complicated cases or failed conservative treatments with the majority resolving with non-operative management. However, there is no clear-cut consensus about the timing of operative intervention. Meticulous surgical practice is the keystone in preventing adhesion formation despite the availability of numerous pharmacological and surgical strategies. This review aims to update the current knowledge of the pathophysiology of adhesion formation, treatment options and various prevention modalities of adhesive small bowel obstruction.

KEYWORDS

diagnosis; laparotomy; prevention; surgery.

Bowel obstruction: signs indicating the need for urgent surgery

Bowel obstruction is common in emergency departments. Obstruction is more common in the small bowel than in the large bowel. The most common cause is postsurgical adhesions. Nowadays, bowel obstruction is diagnosed with multidetector computed tomography (MDCT). MDCT studies for suspected bowel obstruction should focus on four points that need to be mentioned in the report: confirming the obstruction, determining whether there is a single transition point or whether the obstruction is found in a closed loop, establishing the cause of the obstruction, and seeking signs of complications. Identifying signs of ischemia is important in the management of the patient because it enables patients at higher risk of poor outcomes after conservation treatment who could benefit from early surgical intervention to avoid greater morbidity and mortality associated with strangulation and ischemia of the obstructed bowel loop.

Diagnosis and surgical management strategy for pediatric small bowel obstruction: Experience from a single medical center

Identifying Bowel strangulation and the approach and timing of surgical intervention for pediatric SBO are still uncertain. In this study, 75 consecutive pediatric patients with surgically confirmed SBO were retrospectively reviewed. The patients were divided into group 1 (n = 48) and group 2 (n = 27) according to the presence of reversible or irreversible bowel ischemia, which was analyzed based on the degree of ischemia at the time of operation. The results demonstrated that the proportion of patients with no prior abdominopelvic surgery was higher, the serum albumin level was lower, and the proportion of patients in which ascites were detected by ultrasonography was higher in group 2 than that in group 1. The serum albumin level was negatively correlated with ultrasonographic findings of the fluid sonolucent area in group 2. There were significant differences in the choice of surgical approach between group 1 and group 2. A symptom duration of >48 h was associated with an increased bowel resection rate. The mean length of hospital stay was shorter in group 1 than that in group 2. In conclusion, immediate surgical intervention should be considered in patients with a symptom duration of >48 h or the presence of free ascites between dilated small bowel loops on ultrasonography. Laparoscopic exploration is recommended as first-line treatment in patients with stable status.

Complicated Diverticulitis With Associated Small Bowel Obstruction: A Case Report

Diverticulitis is a common disease of the colon with a broad spectrum of presentations. This case outlines a less commonly seen presentation of delayed complicated diverticulitis with abscess formation and associated small bowel obstruction.

This report outlines the case of a 58-year-old obese male who initially presented to the emergency department with uncomplicated diverticulitis, was discharged home, and returned two days later with worsening symptoms. A repeat computed tomography (CT) scan demonstrated abscess formation with an associated small bowel obstruction. He underwent midline exploratory laparotomy with adhesiolysis of the portion of obstructed small bowel and resection of the diseased segment with primary anastomosis and diverting loop ileostomy. He had an ileostomy reversal at a later date.

Small bowel obstruction is a less observed complication of diverticulitis. This report serves to educate on the presentation of these patients as well as to discuss the potential surgical management of these patients. If this patient had presented without the small bowel obstruction, he may have just needed percutaneous drainage.

Point-of-Care Abdominal Ultrasonography (POCUS) on the Way to the Right and Rapid Diagnosis

Point-of-Care ultrasound (POCUS) is based on target ultrasound that is performed wherever a patient is being treated, and by a non-radiologist directly involved in the patient’s care. It is used either for quick diagnosis or procedural guidance. Abdominal pain is one of the most common complaints in emergency departments, and POCUS can help in the differentiation of patients who need additional diagnostic tests or hospital treatment, which eventually reduces the overall costs of health care. POCUS has high sensitivity and specificity in abdominal pathology, it can be helpful in the evaluation of biliary, intestinal, and urinary tract, and it is especially used in trauma. Additionally, the gold standard for abdominal aortic aneurysm detection, follow up and screening is precisely this diagnostic procedure. Unfortunately, the quality of ultrasound examination can be affected by the experience of the physician performing it and the patient’s body weight. There is no doubt that POCUS is being increasingly recognized, but all motivated physicians should be provided with dedicated tutors and enough time for learning. This would certainly help to implement this diagnostic method as a routine in emergency and critical care departments, and significantly shorten the time until definitive diagnosis.

Predicting the outcome of closed-loop small bowel obstruction by preoperative characteristics

BACKGROUND

Closed-loop small bowel obstruction (CL-SBO) can threaten the viability of the intestine by obstructing a bowel segment at two adjacent points. Prompt recognition and surgery are crucial.

AIM

To analyze the outcomes of patients who underwent surgery for CL-SBO and to evaluate clinical predictors.

METHODS

Patients who underwent surgery for suspected CL-BSO on computed tomography (CT) at a single center between 2013 and 2019 were evaluated retrospectively. Patients were divided into three groups by perioperative outcome, including viable bowel, reversible ischemia, and irreversible ischemia. Clinical and laboratorial variables at presentation were compared and postoperative outcomes were analyzed.

RESULTS

Of 148 patients with CL-SBO, 28 (19%) had a perioperative viable small bowel, 86 (58%) had reversible ischemia, and 34 (23%) had irreversible ischemia. Patients with a higher age had higher risk for perioperative irreversible ischemia [odds ratio (OR): 1.03, 95% confidence interval (CI): 0.99-1.06]. Patients with American Society of Anaesthesiologists (ASA) classification ≥ 3 had higher risk of perioperative irreversible ischemia compared to lower ASA classifications (OR: 3.76, 95%CI: 1.31-10.81). Eighty-six patients (58%) did not have elevated C-reactive protein (> 10 mg/L), and between-group differences were insignificant. Postoperative in-hospital stay was significantly longer for patients with irreversible ischemia (median 8 d, P = 0.001) than for those with reversible ischemia (median 6 d) or a viable bowel (median 5 d). Postoperative morbidity was significantly higher in patients with perioperative irreversible ischemia (45%, P = 0.043) compared with reversible ischemia (20%) and viable bowel (4%).

CONCLUSION

Older patients or those with higher ASA classification had an increased risk of irreversible ischemia in case of CL-SBO. After irreversible ischemia, postoperative morbidity was increased.

Predicting the Need for Surgery in Uncomplicated Adhesive Small Bowel Obstruction: A Scoring Tool

INTRODUCTION

Nonoperative treatment can be attempted for uncomplicated adhesive small bowel obstruction (ASBO), but carries a risk of delayed surgery. Highlighting initial parameters predicting risk of failure of nonoperative management would be of great interest.

METHODS

Patients initially managed conservatively for uncomplicated ASBO were retrospectively analyzed. Univariate and multivariate analysis were performed to identify predictive failure's factors. Based on the risk factors, a score was created and then prospectively validated in a different patients' population.

RESULTS

Among 171 patients included, 98 (57.3%) were successfully managed conservatively. In a multivariate analysis, three independent nonoperative management failure's factors were identified: Charlson Index ≥4 (P = 0.016), distal obstruction (P = 0.009), and maximum small bowel diameter over vertical abdominal diameter ratio >0.34 (P = 0.023). A score of two or three was associated with a risk of surgery of 51.4% or 70.3% in the retrospective analysis and 62.2% or 75% in the validation cohort, respectively.

CONCLUSIONS

This clinical-radiological score may help guide surgical decision-making in uncomplicated ASBO. A high score (≥2) was predictive of failure of nonoperative management. This tool could assist surgeons to determine who would benefit from early surgery.

Small bowel obstruction and intestinal ischemia: emphasizing the role of MDCT in the management decision process

The objective of this article is to assess the computed tomography (CT) findings of small bowel obstruction (SBO) complicated by ischemia. SBO is a frequent clinical entity characterized by high morbidity and mortality. The radiologic aim is not just to diagnose the obstruction itself but to rule out the presence of complications related to SBO. This is crucial for differentiating which patients can be safely treated non-operatively from the ones who may need an urgent surgical approach. The main complication of SBO is intestinal ischemia. In the emergency setting, CT imaging is the modality of choice for SBO because of its ability to assess the bowel wall, the supporting mesentery and peritoneal cavity all in one. On the other hand, the radiologist who documents an intestinal ischemia should think about SBO as possible cause. In this case, the main finding which helps the radiologist in the identification of SBO is the presence of multiple and packed valvulae conniventes in the dilated bowel wall and the "transition zone" that indicates the passage between compressed and decompressed small bowel, otherwise the localization of the obstruction cause. Once the site of obstruction has been recognized, the other issue is to assess the cause of obstruction, considering that the most common cause of SBO remains "unidentified" and related to intra-abdominal adhesions. After that, the following most important point is to rule out the presence of an ischemic bowel and mesenteric changes associated to SBO. CT signs of bowel ischemia include reduced or increased bowel wall enhancement, mesenteric edema or engorgement, fluid or free air in the peritoneal cavity. This condition usually leads to an urgent laparotomy and, in some cases, to a surgical resection.

The shadow in the darkness: Case report on adhesive intestinal obstruction secondary to ventriculoperitoneal shunt catheter in an elderly patient

Introduction

Shunt placement is an effective therapy for hydrocephalus. Ventriculoperitoneal shunt draining excess cerebrospinal fluid connects the cerebral ventricles to the abdominal cavity. However, intestinal obstruction may ensue as an infrequent complication of the shunt.

Case presentation

A 65 years old female patient presented with abdominal pain, abdominal bloating, and ceased passage of flatus and stool for six days. She had a history of undergoing a VP shunt procedure due to midbrain obstruction and supratentorial hydrocephalus. Conservative treatment at another local hospital couldn't relieve her symptoms. Laboratory investigations revealed elevated CRP and neutrophils. CT scan showed distended small bowel loops with aerated effusion. Thus, she was admitted to our hospital and underwent an emergent laparotomy following diagnostic modalities completion.

Discussion

Adhesive intestinal obstruction secondary to ventriculoperitoneal shunt is a rare but fatal shunt complication. The possible mechanisms involved include rubbing movements between the greater omentum and the catheter, cerebrospinal fluid reaction with abdominal organs, immunological rejection of the catheter, and deposition of brain tumor cells with the resultant abdominal metastatic lesions. Laparoscopic and laparotomy are warranted in the surgical management of the disease.

Conclusion

A high index of suspicion for adhesive intestinal obstruction is key to timely diagnosis and treatment.

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Ventriculoperitoneal (VP) shunt is the standard treatment for hydrocephalus.

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The common complications include bacterial infection and shunt malfunction.

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Adhesive intestinal obstruction is an infrequent VP catheter complication.

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Focused history, physical examination, and diagnostic modalities are of value.

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In emergencies, laparotomy is key in alleviating the disease's detrimental effects.

Evaluating suspected small bowel obstruction with the water-soluble contrast challenge

With optimized technique, the water-soluble contrast challenge is effective at triaging patients for operative vs non-operative management of suspected small bowel obstruction. Standardized study structure and interpretation guidelines aid in clinical efficacy and ease of use. Many tips and tricks exist regarding technique and interpretation, and their understanding may assist the interpreting radiologist. In the future, a CT-based water-soluble contrast challenge, utilizing oral contrast given as part of the initial CT examination, might allow for a more streamlined algorithm and provide more rapid results.

Evaluation of ischemia and necrosis in adhesive small bowel obstruction based on CT signs: Subjective visual evaluation and objective measurement

PURPOSE

To investigate the diagnostic performance of CT signs for detecting bowel ischemia and necrosis in adhesive small bowel obstruction(SBO) with subjective and objective methods.

MATERIALS AND METHODS

113 adhesive SBO patients were enrolled and divided into ischemic group (49 cases in necrotic group and 35 cases in reversible ischemic group) and non-ischemic group (29 cases) according to the operation results. Subjective visual assessment of CT signs associated with ischemia and necrosis was performed by two radiologists independently. Elevated unenhanced attenuation and enhancement value of involved bowel wall were objectively measured and compared by single factor analysis of variance. Cut-off value and diagnostic performance were evaluated by receiver operating characteristic curve (ROC).

RESULTS

Closed-loop mechanism, reduced bowel wall enhancement, and mesenteric edema were associated with bowel ischemia, with sensitivity of 81.0%, 65.5%, 75.0%, and specificity of 86.2%, 96.6%, 89.7%, respectively. Increased unenhanced bowel wall attenuation was a specific sign for necrosis with 100.0% specificity and 51.0% sensitivity. The sensitivity and specificity for ischemia were 86.0% and 91.9% with cut-off enhancement value lower than 33.5 HU. The sensitivity and specificity for necrosis were 58.2% and 100.0% with cut-off elevated unenhanced attenuation higher than 16.5 HU, 86.7% and 83.3% with cut-off enhancement value lower than 21.5 HU.

CONCLUSION

Reduced bowel wall enhancement and increased unenhanced bowel wall attenuation were good indicators of bowel ischemia and necrosis. The objective measurement of elevated unenhanced attenuation and enhancement value can predict bowel ischemia and necrosis more accurately.

Correlation of CT findings with intra-operative outcome in closed-loop small bowel obstruction (CL-SBO)

PURPOSE

To correlate CT-findings in patients with closed-loop small bowel obstruction (CL-SBO) with perioperative findings, to identify patients who require immediate surgical intervention. Secondary purpose was to substantiate the role of radiologists in predicting perioperative outcome.

METHODS

Data were retrospectively obtained from patients with surgically confirmed CL-SBO, between September 2013 and September 2019. Three radiologists reviewed CTs to assess defined CT features and predict patient outcome for bowel wall ischemia and necrosis using a likelihood score. Univariate statistical analyses were performed and diagnostic performance parameters and interobserver agreement were assessed for each feature.

RESULTS

Of 148 included patients, 28 (19%) intraoperatively had viable bowel and 120 (81%) had bowel wall ischemia or necrosis. Most CT characteristics, as well as the likelihood of ischemia and necrosis, found fair or moderate multirater agreement. Increased attenuation of bowel wall and mesenteric vessels on non-contrast-enhanced CT had a specificity for bowel ischemia or necrosis of 100% (sensitivity respectively 48% (p < 0.001) and 21% (p = 0.09)). Mesenteric edema had high sensitivity for ischemia or necrosis (90%), but specificity of only 26% (p < 0.001). For mesenteric fluid, sensitivity was 60% and specificity 57% (p = 0.004). Decreased enhancement of bowel wall in both arterial and PV-phase showed significant correlation, respectively a sensitivity of 58% and 42%, and specificity of 88% and 79% (both p < 0.001). Likelihood of both ischemia and necrosis were significantly correlated with perioperative outcome (p < 0.001).

CONCLUSION

CT findings concerning mesenteric and bowel wall changes, as well as radiologists' judgement of likelihood of ischemia and necrosis are significantly correlated with perioperative outcome of bowel wall ischemia and necrosis in patients with CL-SBO.

Ultrasound of Small Bowel Obstruction: A Pictorial Review

Small bowel obstruction (SBO) is a common condition requiring urgent attention that may involve surgical treatment. Imaging is essential for the diagnosis and characterization of SBO because the clinical presentation and results of laboratory tests may be nonspecific. Ultrasound is an excellent initial imaging modality for assisting physicians in the rapid and accurate diagnosis of a variety of pathologies to expedite management. In the case of SBO diagnosis, ultrasound has an overall sensitivity of 92% (95% CI: 89–95%) and specificity of 93% (95% CI: 85–97%); the aim of this review is to examine the criteria for the diagnosis of SBO by ultrasound, which can be divided into diagnostic and staging criteria. The diagnostic criteria include the presence of dilated loops and abnormal peristalsis, while the staging criteria are represented by parietal and valvulae conniventes alterations and by the presence of free extraluminal fluid. Ultrasound has reasonably high accuracy compared to computed tomography (CT) scanning and may substantially decrease the time to diagnosis; moreover, ultrasound is also widely used in the monitoring and follow-up of patients undergoing conservative treatment, allowing the assessment of loop distension and the resumption of peristalsis.

Small bowel obstruction with situs inversus abdominalis: A case report

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Intestinal obstruction in an adult with situs inversus abdominalis is extremely rare.

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Management requires early investigation & a lower threshold for surgical intervention.

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Detailed pre-operative planning & surgical experience is essential.

Introduction

Situs inversus abdominalis (SIA) is an uncommon condition that causes intestinal malrotation in the paediatric population as its primary complication (Brown, 2017). Presentations of acute surgical emergencies in adults secondary to SIA are extremely rare (Brown, 2017).

Presentation of case

A 38-year-old female with situs inversus abdominalis (SIA) presented with small bowel obstruction (SBO). The patient had a history of a paediatric omphalocele repair.

The patient failed conservative management and required surgical intervention including a laparotomy and adhesiolysis without intestinal resection for resolution of her symptoms.

Discussion

Only 2 cases of SBO secondary to SIA have been documented in the literature; both resulting in bowel resection with a 50 % mortality rate (Mallick, 2006). This is the third reported case and the only case to avoid bowel ischemia. We attribute this to early presentation by the patient, prompt imaging, careful surgical planning with consultant led surgical intervention and a multidisciplinary team approach to recovery.

Conclusion

Acute surgical emergencies in patients with congenital anomalies should have a low threshold for imaging and intervention with detailed pre-operative planning and a senior surgeon led approach.

Adhesive Small Bowel Obstruction: Predictive Radiology to Improve Patient Management

Adhesive small bowel obstruction (SBO) remains one of the leading causes of emergency room visits and is still associated with high morbidity and mortality rates. Because the management of adhesive SBO has shifted from immediate surgery to nonoperative treatment in the absence of ischemia, it is crucial to rapidly detect or predict strangulation, which requires emergent surgery. CT is now established as the best imaging technique for the initial assessment of patients suspected of having adhesive SBO. CT helps confirm the diagnosis of mechanical SBO, locate the site of obstruction, establish the cause, and detect complications. This article is a review of the role of imaging in answering specific questions to help predict the management needs of each individual patient. It includes (a) an update on the best CT signs for predicting ischemia and a need for bowel resection; (b) a discussion of the CT features that help differentiate open-loop from closed-loop obstruction and a single adhesive band from matted adhesions and how these differences can influence the management; and (c) a review of the main CT predictors of the success or failure of nonoperative management in adhesive SBO.