Prospective, Observational Validation of a Multivariate Small-Bowel Obstruction Model to Predict the Need for Operative Intervention

The utility of a CT grading scale in deciding on surgical intervention for patients with suspected small bowel obstruction

Background

A grading system was developed for computerized tomography (CT) scans evaluating patients with suspected small bowel obstruction (SBO). We hypothesized that patients with a higher grade of suspected SBO on CT scan would be more likely to require surgical intervention.

Methods

Retrospective chart review of patients who presented to the Emergency Room (ER) who had a CT of the abdomen and pelvis for suspected SBO. Patients were divided into 5 groups: Grade 1 (SBO unlikely), Grade 2 (probable partial or early SBO), Grade 3 (probable high grade SBO), Grade 4 (SBO with changes concerning for ischemia) and Not Graded.

Results

The CT scans of 655 patients were graded. Of the 22 patients with a grade 1 SBO, only 1 went for surgery (4.5 %). For grade 2 patients, 23 out of 299 had an operation (7.7 %), for grade 3 it was 84 out of 299 (28.1 %) and for grade 4 SBO, 25 out of 35 patients (71.4 %) had surgery. The p value is <0.00001. The three most common intraoperative findings were SBO obstruction from adhesions alone (48 % of cases), followed by incarcerated hernias (12 %) and ischemic bowel (9 %). Only 8 cases out of 133 operations (6 % of total) had no findings at time of surgery other than dilated bowel.

Conclusions

The CT grading scale for SBO developed at our institution shows excellent correlation between grade and going for surgery, with few negative results, and can be a useful tool among other factors for general surgeons when deciding whether or not to operate on a patient with suspected SBO.

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.

Assessing the Modified Frailty Index and Post-Operative Outcomes in Adhesive Small Bowel Obstruction: A Retrospective Cohort Study

INTRODUCTION

Studies identifying predictors of postoperative outcomes in adhesive small bowel obstruction are limited. This study investigates the efficacy of the modified frailty index (mFI)to predict postoperative morbidity and mortality among patients undergoing surgery for adhesive small bowel obstruction.

METHODS

A multicentre retrospective cohort study including patients undergoing surgery for adhesive small bowel obstruction after failed trial of nonoperative management between January 2015 and December 2020 was performed. Impact of frailty status using the mFI, stratified as frail (≥0.27) and robust (<0.27), on postoperative morbidity, mortality, length of stay, and discharge destination was evaluated using multiple logistic regression.

RESULTS

Ninety-two robust patients (mean age 62.4 y, 68% female) and 41 frail patients (mean age 81.7 y, 63% female) were included. On simple stratification, frail patients had significantly increased 30-d morbidity (overall morbidity 80% versus 49%) and need for higher level of care on discharge (41% versus 9%). However, on multiple regression, functional dependence but not the mFI, was independently associated with worse 30-d overall morbidity (odds ratio [OR] 3.97, confidence interval [CI] 1.29-12.19) and lower likelihood of returning to preoperative disposition (OR 0.21, CI 0.05-0.91). The delay in operation beyond 5 d was independently associated with worse 30-d outcomes including overall morbidity and mortality (OR 7.54, CI 2.13-26.73) and decreased return to preoperative disposition (OR 0.14, CI 0.04-0.56).

CONCLUSIONS

The mFI, although promising, was not independently predictive of outcomes following surgery for adhesive small bowel obstruction. Further adequately powered studies are required.

Comparison of the effect between traditional conservation and nasointestinal tube placement in adhesive small bowel obstruction: A matched case-control study

Adhesive small bowel obstruction (ASBO) causes a major burden in emergency medicine. Owing to in situ decompression, nasointestinal tube (NIT) placement has been increasingly used in clinical practice compared with traditional conservation (TC); however, the indications remain controversial. This study was designed to explore the indications for each treatment in ASBOs and then suggest the optimal strategy. After propensity score matching, 128 pairs were included (the NIT and TC groups). The occurrence of severe adverse events (SAEs), peri-treatment clinical parameters, and radiological features were compared between the successful and failed treatment groups. According to different stages of the entire treatment, the independent risk factors for adverse effects for ASBO were analysed in phase I and phase II. In phase I, normal red blood cells (RBC) levels (p = 0.011) and a balanced sodium ion level (p = 0.016) positively affected the outcomes of TC treatment. In phase II, for the TC group, the successful treatment rate reached 79.5% for patients with ASBOs whose normal RBC levels (p = 0.006) or decreasing white blood cells (WBC) levels (p = 0.014) after treatment. For the NIT group, the treatment success rate was 68.1% for patients whose electrolyte imbalance could be reversed or whose neutrophil count/lymphocyte ratio (NLR) levels was lower than 4.3 (p = 0.018). TC treatment is highly recommended for patients with normal RBC counts and sodium levels pretreatment. After dynamic monitoring of the treatment process, for both the TC and NIT groups, once ASBOs had elevated inflammatory biomarkers or irreversible electrolyte disturbances, surgical interference was preferred.

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.

Small Bowel Obstruction in Virgin Abdomen: Predictors of Surgical Intervention Need in Resource-Limited Setting

Background

Limited evidence is available regarding the management of small bowel obstruction in the virgin abdomen (SBO-VA), with most studies excluding this entity. This study aims to assess the available data on the treatment outcomes and predictors of surgical intervention in SBO-VA.

Methods

A retrospective cross-sectional study was conducted between 2015 and 2021, including all diagnosed and managed cases of SBO-VA at Al-Nasar Hospital. Patients were divided according to the treatment approach into surgical or conservative groups. Preoperative laboratory and radiologic data were gathered and compared between groups.

Results

During the study period, 67 cases, primarily males (58.2%), with an average age of 52.2±14.4 years were assessed. Common comorbidities included diabetes (20.9%) and hypertension (16.4%). Key symptoms were rebound tenderness (82.1%) and abdominal tenderness (70.1%). The predominant etiology was adhesions (23.9%). About 46.2% received conservative treatment, 53.8% underwent urgent surgery. Conservative treatment failed in 9.4% of cases, and complications arose in 23.9%, with most being fever (17.9%). Factors necessitating surgical management included older age (58.8 ±11.7 vs 44.9 ±13.8 years, p<0.001), previous hospital admission (p<0.001), presence of abdominal tenderness (p=0.030), longer abdominal pain duration (4.0 ±0.9 vs 2.1 ±0.6 days, p<0.001), higher C- reactive protein (p= 0.033), higher white blood cell (p= 0.006), longer time to hospital presentation (75.3 ±17.2 vs 39.0 ±22.8 days, p= <0.001), small bowel thickness ≥3 cm (p=0.009), and reduced bowel enhancement (p <0.001) on computed tomography imaging. In surgical group, the need for ICU admission was higher and hospital stays were shorter than in conservative group and were statistically significant (p<0.05).

Conclusion

The main etiology of SBO-VA in our study was adhesions. Older age, previous hospital admission, longer abdominal pain duration, abdominal tenderness, increased inflammatory markers, and alarm signs on CT scans are the main factors for determining the need for urgent surgical exploration in patients with SBO-VA. To achieve prompt identification and intervention, it is crucial to maintain a high level of vigilance and awareness, even in individuals with no prior surgical history.

Predictors for success of non-operative management of adhesive small bowel obstruction

BACKGROUND

Majority of adhesive small bowel obstruction (SBO) cases can be managed non-operatively. However, a proportion of patients failed non-operative management.

AIM

To evaluate the predictors of successful non-operative management in adhesive SBO.

METHODS

A retrospective study was performed for all consecutive cases of adhesive SBO from November 2015 to May 2018. Data collated included basic demographics, clinical presentation, biochemistry and imaging results and management outcomes. The imaging studies were independently analyzed by a radiologist who was blinded to the clinical outcomes. The patients were divided into group A operative (including those that failed initial non-operative management) and group B non-operative for analysis.

RESULTS

Of 252 patients were included in the final analysis; group A (n = 90) (35.7%) and group B (n = 162) (64.3%). There were no differences in the clinical features between both groups. Laboratory tests of inflammatory markers and lactate levels were similar in both groups. From the imaging findings, the presence of a definitive transition point [odds ratio (OR) = 2.67, 95% confidence interval (CI): 0.98-7.32, P = 0.048], presence of free fluid (OR = 2.11, 95%CI: 1.15-3.89, P = 0.015) and absence of small bowel faecal signs (OR = 1.70, 95%CI: 1.01-2.88, P = 0.047) were predictive of the need of surgical intervention. In patients that received water soluble contrast medium, the evidence of contrast in colon was 3.83 times predictive of successful non-operative management (95%CI: 1.79-8.21, P = 0.001).

CONCLUSION

The computed tomography findings can assist clinicians in deciding early surgical intervention in adhesive SBO cases that are unlikely to be successful with non-operative management to prevent associated morbidity and mortality.

Diseño y validación de una herramienta para la predicción de desenlaces adversos en pacientes con obstrucción intestinal por bridas: La escala HALVIC

Introducción. La obstrucción intestinal por bridas representa una causa común de consulta a los servicios de urgencias, pero hay poca claridad sobre qué pacientes tienen mayor riesgo de desarrollar complicaciones. El objetivo de este estudio fue diseñar y validar una escala de predicción de riesgo de desenlaces adversos en pacientes con obstrucción intestinal por bridas. Métodos. Estudio de cohorte retrospectivo realizado a partir de la base de datos MIMIC-IV. Se incluyeron pacientes adultos admitidos al servicio de urgencias entre 2008 y 2019, con diagnóstico de obstrucción intestinal por bridas. El desenlace principal fue el compuesto de resección intestinal, ingreso a unidad de cuidados intensivos y mortalidad por cualquier causa. Se diseñó una escala de predicción de riesgo asignando un puntaje a cada variable. Resultados. Se incluyeron 513 pacientes, 63,7 % hombres. El desenlace compuesto se presentó en el 25,7 % de los casos. La edad, historia de insuficiencia cardiaca y enfermedad arterial periférica, nivel de hemoglobina, recuento de leucocitos e INR constituyeron el mejor modelo de predicción de estos desenlaces (AUC 0,75). A partir de este modelo, se creó la escala simplificada HALVIC, clasificando el riesgo del desenlace compuesto en bajo (0-2 puntos), medio (3-4 puntos) y alto (5-7 puntos). Conclusión. La escala HALVIC es una herramienta de predicción simple y fácilmente aplicable. Puede identificar de manera precisa los pacientes con obstrucción intestinal por bridas con alto riesgo de complicaciones, permitiendo el ajuste individualizado de las estrategias de manejo para mejorar los desenlaces.

Diagnostic nomogram for closed-loop small bowel obstruction requiring emergency surgery

PURPOSE

This study aimed to build a diagnostic model of closed-loop small bowel obstruction (CL-SBO) using clinical information, blood test results, and computed tomography (CT) findings.

METHODS

All patients who were diagnosed with small bowel obstruction (SBO) and underwent surgery between January 1, 2018, and October 31, 2021, in the affiliated hospital of Qingdao university were reviewed, and their relevant preoperative information was collected. All variables were selected using univariate analysis and backward stepwise regression to build a diagnostic nomogram model. K-fold cross-validation and bootstrap resampling techniques were used for internal validation, and data from Qingdao Central Hospital were used for external validation. We also evaluated the diagnostic performance of each CT finding and performed subgroup analysis according to bowel ischemia in the closed-loop small bowel obstruction (CL-SBO) group.

RESULTS

A total of 219 patients (95 in the CL-SBO group and 124 in the open-loop small bowel obstruction [OL-SBO] group) were included in our research. D-dimers (median 1085 vs. 690, P = 0.019), tenderness (77.9% vs. 59.7%, P = 0.004), more than one beak sign (65.3% vs. 30.6%, P < 0.001), radial distribution (18.9% vs. 6.5%, P = 0.005), whirl sign (35.8% vs. 8.9%, P < 0.001), and ascites (71.6% vs. 53.2%, P = 0.006) were selected as the predictive variables of the nomogram. This model's Harrell's C statistic was 0.786 (95% confidence interval (CI), 0.724-0.848), and the Brier score was 0.182. The Harrell's C statistic of external validation was 0.784 (95%CI, 0.664-0.905); the Brier score was 0.190. Regarding the CT findings, radial distribution, U/C-shaped loop, and whirl sign had high specificity (93.5%, 96.0%, and 91.1%, respectively), but low sensitivity (18.9%, 8.4%, and 35.8%, respectively). D-dimer levels and tenderness were also associated with bowel ischemia.

CONCLUSION

The nomogram accurately predicted CL-SBO in patients with SBO, and surgery should be considered when patients have a high risk for developing CL-SBO.

Current Management of Adhesive Small Bowel Obstructions in Children

Adhesive small bowel obstructions are a common cause of morbidity in children who underwent prior abdominal surgery. The concept of partial versus complete bowel obstruction is outdated and lacks precision to be clinically useful. Identifying patients with indications for immediate operative intervention is critical and must be recognized to limit morbidity. Clinical protocols and contrast challenge algorithms have attempted to identify patients that will resolve their bowel obstruction nonoperatively; there has been slow uptake in the pediatric patient population versus adults until recently. Incorporating predictive models and standardized contrast challenge protocols will help reduce interpractitioner variability and improve clinical outcomes.

Preoperative prediction of inadvertent enterotomy during adhesive small bowel obstruction surgery using combination of CT features

OBJECTIVES

The purpose of this study was to identify the preoperative CT features that are associated with inadvertent enterotomy (IE) during adhesive small bowel obstruction (ASBO) surgery.

METHODS

From January 2015 to December 2019, all patients with ASBO who underwent an abdominal CT were reviewed. Abdominal CT were retrospectively reviewed by two radiologists with a consensus read in case of disagreement. IE during ASBO surgery was retrospectively recorded. Univariate and multivariate analyses of CT features associated with IE were performed and a simple CT score was built to stratify the risk of IE. This score was validated in an independent retrospective cohort. Abdominal CT of the validation cohort was reviewed by a third independent reader.

RESULTS

Among the 368 patients with ASBO during the study period, 169 were surgically treated, including 129 ASBO for single adhesive band and 40 for matted adhesions. Among these, there were 47 IE. By multivariate analysis, angulation of the transitional zone (OR = 4.19, 95% CI [1.10-18.09]), diffuse intestinal adhesions (OR = 4.87, 95% CI [1.37-19.76]), a fat notch sign (OR = 0.32, 95% CI [0.12-0.85]), and mesenteric haziness (OR = 0.13, 95% CI [0.03-0.48]) were independently associated with inadvertent enterotomy occurrence. The simple CT score built to stratify risk of IE displayed an AUC of 0.85 (95% CI [0.80-0.90]) in the study sample and 0.88 (95% CI [0.80-0.96]) in the validation cohort.

CONCLUSION

A simple preoperative CT score is able to inform the surgeon about a high risk of IE and therefore influence the surgical procedure.

KEY POINTS

• In this retrospective study of 169 patients undergoing abdominal surgery for adhesive small bowel obstruction, 47 (28%) inadvertent enterotomy occurred. • A simple preoperative CT score enables accurate stratification of inadvertent enterotomy risk (area under the curve 0.85). • By multivariable analysis, diffuse intestinal adhesions and angulation of the transitional zone were predictive of inadvertent enterotomy occurrence.

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.

Prediction and management of strangulated bowel obstruction: a multi-dimensional model analysis

BACKGROUND

Distinguishing strangulated bowel obstruction (StBO) from simple bowel obstruction (SiBO) still poses a challenge for emergency surgeons. We aimed to construct a predictive model that could distinctly discriminate StBO from SiBO based on the degree of bowel ischemia.

METHODS

The patients diagnosed with intestinal obstruction were enrolled and divided into SiBO group and StBO group. Binary logistic regression was applied to identify independent risk factors, and then predictive models based on radiological and multi-dimensional models were constructed. Receiver operating characteristic (ROC) curves and the area under the curve (AUC) were calculated to assess the accuracy of the predicted models. Via stratification analysis, we validated the multi-dimensional model in the prediction of transmural necrosis both in the training set and validation set.

RESULTS

Of the 281 patients with SBO, 45 (16.0%) were found to have StBO, while 236(84.0%) with SiBO. The AUC of the radiological model was 0.706 (95%CI, 0.617-0.795). In the multivariate analysis, seven risk factors including pain duration ≤ 3 days (OR = 3.775), rebound tenderness (OR = 5.201), low-to-absent bowel sounds (OR = 5.006), low levels of potassium (OR = 3.696) and sodium (OR = 3.753), high levels of BUN (OR = 4.349), high radiological score (OR = 11.264) were identified. The AUC of the multi-dimensional model was 0.857(95%CI, 0.793-0.920). In the stratification analysis, the proportion of patients with transmural necrosis was significantly greater in the high-risk group (24%) than in the medium-risk group (3%). No transmural necrosis was found in the low-risk group. The AUC of the validation set was 0.910 (95%CI, 0.843-0.976). None of patients in the low-risk and medium-risk score group suffered with StBO. However, all patients with bowel ischemia (12%) and necrosis (24%) were resorted into high-risk score group.

CONCLUSION

The novel multi-dimensional model offers a useful tool for predicting StBO. Clinical management could be performed according to the multivariate score.

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.

Association of Daily Variance in Air Temperature With Postoperative Adhesive Small Bowel Obstruction

Introduction: The influence of air temperature on adhesive small bowel obstruction (ASBO) is unknown. This study aimed to investigate the relationship between air temperature and postoperative ASBO.

Methods: Overall, 312 patients with postoperative ASBO were included. They were categorized into two groups: the surgery group (n = 83) comprising patients who needed surgery, and the non-surgery group (n = 229) comprising patients who responded to conservative treatment. The associations between patients’ characteristics and weather variables on days of symptom onset with the need for surgical management were investigated. Weather variables included the daily mean barometric pressure, daily mean air temperature, day-to-day differences, daily variances, and diurnal variation in the air temperature. Day-to-day differences in weather variables were calculated as the daily mean variables on the day of symptom onset minus those on the previous day. The daily variances in weather variables were defined as the absolute value of day-to-day differences.

Results: Compared to the non-surgery group, the surgery group had older patients (75 vs. 70 years, p = 0.009), a higher proportion of female patients (44.6% vs. 32.3%, p = 0.046), increased incidence of closed-loop sign (50.6% vs. 0.9%, p < 0.001), a lower proportion of feces sign (18.1% vs. 31.3%, p = 0.024), and a prolonged hospital stay (11 vs. 22 days, p < 0.001). The number distribution of patients in the surgery group in day-to-day differences in air temperature was different from that of the non-surgery group; the former has several peaks whereas the latter has almost one peak. Daily variance in mean air temperature on the day of symptom onset was higher in the surgery group than in the non-surgery group (2.3 vs. 1.3℃, p < 0.001). Multiple logistic regression analysis revealed that increased daily variance in air temperature on the onset day was associated with the need for surgical management (odds ratio 1.254, p = 0.002) and closed-loop obstruction (odds ratio 1.235, p = 0.017). Regarding seasonal variations, the risk of the need for surgery and closed-loop obstruction in each ASBO patient was the highest in spring, followed by that in summer, autumn, and winter. Consistently, the daily variance in mean air temperature in spring was higher than that in summer, autumn, and winter (p < 0.0001, p < 0.0001, and p = 0.0047, respectively). The risk of the need for surgery and closed-loop obstruction in each ASBO patient was the highest in spring, followed by that in summer, autumn, and winter. Consistently, daily variance in mean air temperature was higher in spring than that in summer, autumn, and winter (p < 0.0001, p < 0.0001, and p = 0.0047, respectively).

Conclusion: Increased daily variance in mean air temperature on the day of onset is associated with the need for surgical management and closed-loop obstruction. Spring is characterized by the highest daily variance in mean air temperature among the four seasons, and is associated with high proportions of the need for surgery and closed-loop obstruction. These results can be clinically useful in terms of hospital resource reallocation and staffing, and can help clarify the pathogenesis of ASBO.

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.

Small bowel obstruction managed without hospital admission: A safe way to reduce both cost and time in the hospital?

BACKGROUND

Small bowel obstruction management has evolved to incorporate the Gastrografin challenge. We expanded its use to the emergency department observation unit, potentially avoiding hospital admission for highly select small bowel obstruction patients. We hypothesized that the emergency department observation unit small bowel obstruction protocol would reduce admissions, costs, and the total time spent in the hospital without compromising outcomes.

METHODS

We reviewed patients who presented with small bowel obstruction from January 2015 to December 2018. Patients deemed to require urgent surgical intervention were admitted directly and excluded. The emergency department observation unit small bowel obstruction guidelines were introduced in November 2016. Patients were divided into pre and postintervention groups based on this date. The postintervention group was further subclassified to examine the emergency department observation unit patients. Cost analysis for each patient was performed looking at number of charges, direct costs, indirect cost, and total costs during their admission.

RESULTS

In total, 125 patients were included (mean age 69 ± 14.3 years). The preintervention group (n = 62) and postintervention group (n = 63) had no significant difference in demographics. The postintervention group had a 51% (36.7 hours, P < .001) reduction in median duration of stay and a total cost reduction of 49% (P < .001). The emergency department observation unit subgroup (n = 46) median length of stay was 23.6 hours. The readmission rate was 16% preintervention compared to 8% in the postintervention group (P = .18).

CONCLUSION

Management of highly selected small bowel obstruction patients with the emergency department observation unit small bowel obstruction protocol was associated with decreased length of stay and total cost, without an increase in complications, surgical intervention, or readmissions.

Sex differences in non-strangulated postoperative adhesive small bowel obstruction: A retrospective cohort study

BACKGROUND

Adhesive small bowel obstruction (ASBO) is one of the major causes of postoperative morbidity. Non-surgical management is generally applied to non-strangulated ASBO. Several factors have been reported to affect the response to non-surgical management in patients with ASBO. However, the association between sex differences and non-strangulated ASBO remains unclear. This study aimed to elucidate the effect of sex differences in non-strangulated postoperative ASBO.

METHODS

We divided 139 patients with a first episode of non-strangulated postoperative ASBO into two groups: male group (n = 83) and female group (n = 56). Clinical features and prognosis were compared between the two groups.

RESULTS

Female patients had lower proportions of oesophageal/gastric malignancies (P = 0.044) and colorectal malignancies (P = 0.030) and a higher proportion of uterine/ovarian malignancies (P < 0.001) than male patients did. More female patients required surgical management than male patients (P = 0.003) did. Hospital length of stay (LOS) was longer (P = 0.046) in the female group than in the male group. Multiple logistic regression analysis showed that the female sex was associated with an increased risk of the need for surgical management (odds ratio 5.318, P = 0.006). Cox proportional hazards regression analysis revealed that the female sex was positively associated with increased LOS (hazard ratio 0.687, P = 0.045).

CONCLUSION

Female sex was associated with failure of non-surgical management and increased LOS in patients with non-strangulated postoperative ASBO.

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.

Small bowel obstruction due to a congenital adhesion: a rare case report

The exact incidence of small bowel obstruction (SBO) due to congenital adhesions remains unclear. Herein, we report a 59-year-old male who appeared in the emergency department with diffuse abdominal pain associated with vomiting. The patient reported no previous medical or surgical history. Clinical examination revealed a soft, distended abdomen and diffuse tenderness. Computed tomography indicated a close loop obstruction. A congenital band extending from mesentery to ileum and causing an internal hernia was identified via a midline incision. The band was ligated and divided. There is no difference in the clinical presentation, and the initial work-up of SBO on account of congenital adhesions was compared to other bowel obstruction causes. Surgical exploration is crucial for the diagnosis and treatment of congenital adhesions. Although laparotomy is considered the cornerstone of surgical management, laparoscopy has emerged as a feasible and safe alternative for the diagnosis and treatment of these congenital bands.

Diagnosis and management of small bowel obstruction in virgin abdomen: a WSES position paper

Background

Small bowel obstruction (SBO) is a common surgical emergency, causing high morbidity and healthcare costs. The majority of SBOs are caused by adhesions that result from previous surgeries. Bowel obstruction, however, also occurs in patients without previous operation or known pathology, a so called virgin abdomen. It is unknown if small bowel obstruction in the virgin abdomen (SBO-VA) can be managed according to the same principles as other cases of small bowel obstruction. The aim of this position paper is to evaluate the available evidence on etiology and management of small bowel obstruction in the virgin abdomen.

Methods

This is a narrative review with scoping aspects. Clinical topics covered in this review include epidemiology and etiology of SBO-VA, diagnosis and imaging, initial assessment, the role of surgical management in SBO-VA, and the role of non-operative management in SBO-VA.

Results

Our scoping search revealed seven original studies reporting original patient data related to SBO-VA. All the included studies are retrospective cohorts, with populations ranging between 44 and 103 patients with SBO-VA. Adhesions were found to be the cause of the obstruction in approximately half of the reported cases of SBO-VA. A relatively high number of cases of SBO-VA were managed surgically with studies reporting 39–83%. However, in cases where a trial of non-operative management was started, this was generally successful.

Conclusion

The data available suggest that etiology and treatment results for patients with SBO-VA are largely comparable to the results in patients with SBO after previous abdominal surgery. We therefore propose that patients with a virgin abdomen could be treated according to existing guidelines for SBO and adhesive small bowel obstruction.

Computed Tomography in Emergency Diagnosis and Management Considerations of Small Bowel Obstruction for Surgical vs. Non-surgical Approach

BACKGROUND

Small bowel obstruction (SBO) accounts for 15% of abdominal pain complaints referred to emergency departments and imposes significant financial burdens on the healthcare system. The absence of passage of flatus or stool and abdominal distention are reported as the most common symptom and a sign of SBO, respectively. Patients who do not demonstrate severe clinical or imaging findings are typically treated with conservative approaches. Patients with clinical signs of sepsis or physical findings of peritonitis are often instantly transferred to the operating room without supplementary imaging assessment. However, in cases where symptoms are non-specific, or the physical examination is challenging, such as in cases with loss of consciousness, the diagnosis can be complicated. This paper discusses the key findings detectable on Computed tomography (CT), which are vital for the emergent triage, proper treatment, and decision making in patients with speculated SBO.

METHOD

Narrative review of the literature.

RESULTS AND CONCLUSION

CT plays a key role in emergent triage, proper treatment, and decision making. It provides high sensitivity, specificity, and accuracy in the detection of early-stage obstruction and acute intestinal vascular compromise. It can also differentiate between various etiologies of this entity which is considered an important criterion in the triage of patients into surgical vs. non-surgical treatment. There are multiple CT findings, such as mesenteric edema, lack of the small-bowel feces, bowel wall thickening, fat stranding in the mesentery, and intraperitoneal fluid, which are predictive of urgent surgical exploration.

Small Bowel Obstruction Induced by Concurrent Postoperative Intra-Abdominal Adhesions and Small Bowel Fecal Materials in a Young Dog

A 7-month-old neutered male poodle dog presented with general deterioration and gastrointestinal symptoms after two separate operations: a jejunotomy for small-intestinal foreign body removal and an exploratory laparotomy for diagnosis and treatment of the gastrointestinal symptoms that occurred 1 month after the first surgery. The dog was diagnosed as having small-bowel obstruction (SBO) due to intra-abdominal adhesions and small-bowel fecal material (SBFM) by using abdominal radiography, ultrasonography, computed tomography, and laparotomy. We removed the obstructive adhesive lesion and SBFM through enterotomies and applied an autologous peritoneal graft to the released jejunum to prevent re-adhesion. After the surgical intervention, the dog recovered quickly and was healthy at 1 year after the surgery without gastrointestinal signs. To our knowledge, this study is the first report of a successful treatment of SBO induced by postoperative intra-abdominal adhesions and SBFM after laparotomies in a dog.

Computed Tomography Findings Predicting the Need for Surgery in Cases of Small Bowel Obstruction: Emphasis on Duodenal Distension

OBJECTIVE

The aim of the study is to retrospectively evaluate the utility of computed tomography (CT) findings, especially newly defined duodenal distension, for predicting the need to operate on small bowel obstruction (SBO) cases.

METHODS

During a 51-month period, 228 patients (100 women and 128 men; mean age, 55 years) were included in this study, among 438 patients who were hospitalized with a prediagnosis of SBO. The final study population was then divided into 2 groups: a surgery group (n = 76) and a conservative group (n = 152). The CT findings of the SBO patients whose treatment decisions and outcomes were unknown were examined by 2 gastrointestinal radiologists with consensus. Statistical analyses were conducted using univariate and binary logistic regression analyses.

RESULTS

According to the univariate analysis, the degree of obstruction (P = 0.001), small bowel diameter (P = 0.014), and presence of mesenteric fluid (P < 0.001), intraperitoneal free fluid (P = 0.04), intra-abdominal free gas (P < 0.001), and duodenal distension (P < 0.001) showed statistically significant differences between the surgery and conservative groups. However, there were no statistically significant group differences regarding the presence of a transition point, small bowel feces or mesenteric congestion. According to the binary logistic regression analysis, the degree of obstruction (P = 0.012), presence of mesenteric fluid (P = 0.008), intra-abdominal free gas (P = 0.019), and duodenal distension (P < 0.001) were significant predictors of the need for surgery in SBO cases.

CONCLUSIONS

Duodenal distension as a CT finding predicted the need for surgery in SBO cases.

Bowel Ischemia Score Predicts Early Operation in Patients With Adhesive Small Bowel Obstruction

BACKGROUND

Nonoperative management of adhesive small bowel obstruction (SBO) is successful in up to 80% of patients. Current recommendations advocate for computed tomography (CT) scan in all patients with SBO to supplement surgical decision-making. The hypothesis of this study was that cumulative findings on CT would predict the need for operative intervention in the setting of SBO.

METHODS

This is an analysis of a retrospectively and prospectively collected adhesive SBO database over a 6-year period. A Bowel Ischemia Score (BIS) was developed based on the Eastern Association for the Surgery of Trauma guidelines of CT findings suggestive of bowel ischemia. One point was assigned for each of the six variables. Early operation was defined as surgery within 6 hours of CT scan.

RESULTS

Of the 275 patients in the database, 249 (90.5%) underwent CT scan. The operative rate was 28.3% with a median time from CT to operation of 21 hours (Interquartile range 5.2-59.2 hours). Most patients (166/217, 76.4%) with a BIS of 0 or 1 were successfully managed nonoperatively, whereas the majority of those with a BIS of 3 required operative intervention (5/6, 83.3%). The discrimination (area under the receiver operating characteristic curve) of BIS for early surgery, any operative intervention, and small bowel resection were 0.83, 0.72, and 0.61, respectively.

CONCLUSION

The cumulative signs of bowel ischemia on CT scan represented by BIS, rather than the presence or absence of any one finding, correlate with the need for early operative intervention.

Association of feces sign with prognosis of non-emergency adhesive small bowel obstruction

BACKGROUND

/Objective: The feces sign has been reported as a possible predictive factor for non-operative treatment of small bowel obstruction. However, its relationship with prognosis of non-emergency adhesive small bowel obstruction remains unclear. This study aimed to clarify the relationship between the feces sign and prognosis of non-emergency adhesive small bowel obstruction.

METHODS

Ninety-two patients with non-emergency adhesive small bowel obstruction with the transitional zone visible on computed tomography were included. Patients were categorized into two groups: feces sign positive (n = 40) and negative (n = 52). Clinical features and prognosis were compared between the two groups. Cox proportional hazards regression models incorporating the feces sign were used to analyze odds of diet resumption and discharge.

RESULTS

Patients with feces sign were younger (p = 0.015), had a higher body mass index (p = 0.027), and a lower white blood cell count (p = 0.019) on admission. More patients with feces sign were successfully treated with fasting and/or nasogastric tube placement (p < 0.001), and no patient with feces sign suffered from recurrent obstruction after diet resumption. Kaplan-Meier analysis showed that patients with feces sign took less time for diet resumption (p = 0.007) and discharge (p = 0.004) than those without it. Using Cox proportional hazards regression model, the feces sign was reported as an independent predictor of diet resumption (odds ratio 1.685, p = 0.018) and discharge (odds ratio 1.861, p = 0.007).

CONCLUSIONS

The feces sign is associated with improved odds for diet resumption and discharge.

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.

Letting the Sun Set on Small Bowel Obstruction: Can a Simple Risk Score Tell Us When Nonoperative Care is Inappropriate?

Controversy remains as to which patients with small bowel obstruction (SBO) need immediate surgery and which may be managed conservatively. This study evaluated the ability of clinical risk factors to predict the failure of nonoperative management of SBO. The electronic medical record was used to identify all patients with SBO over one year. Clinical, laboratory, and imaging data were recorded. Univariate and multivariable analyses were performed to identify risk factors predicting need for surgery. Cox proportional hazards regression was used to identify risk factors that influence need and timing for surgery. Two hundred nineteen consecutive patients were included. Most patients did not have a prior history of SBO (75%), radiation therapy (92%), or cancer (70%). The majority had undergone previous abdominal or pelvic surgery (82%). Thirty-five per cent of patients ultimately underwent laparotomy. Univariate analysis showed that persistent abdominal pain, abdominal distention, nausea and vomiting, guarding, obstipation, elevated white blood cell count, fever present 48 hours after hospitalization, and high-grade obstruction on computed tomography (CT) scan were significant predictors of the need for surgery. Multivariable analysis revealed that persistent abdominal pain or distention (hazard ratio [HR], 3.04; P = 0.013), both persistent abdominal pain and distention (HR, 4.96; P < 0.001), fever at 48 hours (HR, 3.66; P = 0.038), and CT-determined high-grade obstruction (HR, 3.45; P = 0.017) independently predicted the need for surgery. Eighty-five per cent of patients with none of these four significant risk factors were successfully managed nonoperatively. Conversely, 92 per cent of patients with three or more risk factors required laparotomy. This analysis revealed four readily evaluable clinical parameters that may be used to predict the need for surgery in patients presenting with SBO: persistent abdominal pain, abdominal distention, fever at 48 hours, and CT findings of high-grade obstruction. These factors were combined into a predictive model that may of use in predicting failure of nonoperative SBO management. Early operation in these patients should decrease length of stay and diagnostic costs.

ACR Appropriateness Criteria® Suspected Small-Bowel Obstruction

Small-bowel obstruction is a common cause of abdominal pain and accounts for a significant proportion of hospital admissions. Radiologic imaging plays the key role in the diagnosis and management of small-bowel obstruction as neither patient presentation, the clinical examination, nor laboratory testing are sufficiently sensitive or specific enough to diagnose or guide management. This document focuses on the imaging evaluation of the two most commonly encountered clinical scenarios related to small-bowel obstruction: the acute presentation and the more indolent, low-grade, or intermittent presentation. This document hopes to clarify the appropriate utilization of the many imaging procedures that are available and commonly employed in these clinical settings. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

The American Association for the Surgery of Trauma Severity Grade is valid and generalizable in adhesive small bowel obstruction

BACKGROUND

The American Association for the Surgery of Trauma (AAST) anatomic severity grading system for adhesive small bowel obstruction (ASBO) was validated at a single institution. We aimed to externally validate the AAST ASBO grading system using the Eastern Association for the Surgery of Trauma multi-institutional small bowel obstruction prospective observational study.

METHODS

Adults (age ≥ 18) with (ASBO) were included. Baseline demographics, physiologic parameters (heart rate, blood pressure, respiratory rate), laboratory tests (lactate, hemoglobin, creatinine, leukocytosis), imaging findings, operative details, length of stay, and Clavien-Dindo complications were collected. The AAST ASBO grades were assigned by two independent reviewers based on imaging findings. Kappa statistic, univariate, and multivariable analyses were performed.

RESULTS

There were 635 patients with a mean (±SD) age of 61 ± 17.8 years, 51% female, and mean body mass index was 27.5 ± 8.1. The AAST ASBO grades were: grade I (n = 386, 60.5%), grade II (n = 135, 21.2%), grade III (n = 59, 9.2%), grade IV (n = 55, 8.6%). Initial management included: nonoperative (n = 385; 61%), laparotomy (n = 200, 31.3%), laparoscopy (n = 13, 2.0%), and laparoscopy converted to laparotomy (n = 37, 5.8%). An increased median [IQR] AAST ASBO grade was associated with need for conversion to an open procedure (2 [1-3] vs. 3 [2-4], p = 0.008), small bowel resection (2 [2-2] vs. 3 [2-4], p < 0.0001), postoperative temporary abdominal closure (2 [2-3] vs. 3 [3-4], p < 0.0001), and stoma creation (2 [2-3] vs. 3 [2-4], p < 0.0001). Increasing AAST grade was associated with increased anatomic severity noted on imaging findings, longer duration of stay, need for intensive care, increased rate of complication, and higher Clavien-Dindo complication grade.

CONCLUSION

The AAST ASBO severity grading system has predictive validity for important clinical outcomes and allows for standardization across institutions, providers, and future research focused on optimizing preoperative diagnosis and management algorithms.

LEVEL OF EVIDENCE

Prognostic, level III.

Emergency Medicine Evaluation and Management of Small Bowel Obstruction: Evidence-Based Recommendations

BACKGROUND

Small bowel obstruction (SBO) is a commonly diagnosed disease in the emergency department (ED). Recent literature has evaluated the ED investigation and management of SBO.

OBJECTIVE

This review evaluates the ED investigation and management of adult SBO based on the current literature.

DISCUSSION

SBO is most commonly due to occlusion of the small intestine, resulting in fluid and gas accumulation. This may progress to mucosal ischemia, necrosis, and perforation. A variety of etiologies are present, but in adults, adhesions are the most common cause. Several classification systems are present. However, the most important distinction is complete vs. partial and complicated vs. simple obstruction, as complete complicated SBO more commonly requires surgical intervention. History and physical examination can vary, but the most reliable findings include prior abdominal surgery, history of constipation, abdominal distension, and abnormal bowel sounds. Signs of strangulation include fever, hypotension, diffuse abdominal pain, peritonitis, and several others. Diagnosis typically requires imaging, and though plain radiographs are often ordered, they cannot exclude the diagnosis. Computed tomography and ultrasound are reliable diagnostic methods. Management includes intravenous fluid resuscitation, analgesia, and determining need for operative vs. nonoperative therapy. Nasogastric tube is useful for patients with significant distension and vomiting by removing contents proximal to the site of obstruction. Surgery is needed for strangulation and those that fail nonoperative therapy. Surgical service evaluation and admission are recommended.

CONCLUSION

SBO is a common reason for admission from the ED. Knowledge of recent literature can optimize diagnosis and management.

Application of the AAST EGS Grade for Adhesive Small Bowel Obstruction to a Multi-national Patient Population

BACKGROUND

The American Association for the Surgery of Trauma (AAST) anatomic severity grading system for adhesive small bowel obstruction (ASBO) has demonstrated to be a valid tool in North American patient populations. Using a multi-national patient cohort, we retrospectively assessed the validity the AAST ASBO grading system and estimated disease severity in a global population in order to correlate with several key clinical outcomes.

METHODS

Multicenter retrospective review during 2012-2016 from four centers, Minnesota USA, Bologna Italy, Pietermaritzburg South Africa, and Bucharest Romania, was performed. Adult patients (age ≥ 18) with ASBO were identified. Baseline demographics, physiologic parameters, laboratory results, operative and imaging details, outcomes were collected. AAST ASBO grades were assigned by independent reviewers. Univariate and multivariable analyses with odds ratio (OR) and 95% confidence intervals (CIs) were performed.

RESULTS

There were 789 patients with a median [IQR] age of 58 [40-75] years; 47% were female. The AAST ASBO grades were I (n = 180, 23%), II (n = 443, 56%), III (n = 87, 11%), and IV (n = 79, 10%). Successful non-operative management was 58%. Conversion rate from laparoscopy to laparotomy was 33%. Overall mortality and complication and temporary abdominal closure rates were 2, 46, and 4.7%, respectively. On regression, independent predictors for mortality included grade III (OR 4.4 95%CI 1.1-7.3), grade IV (OR 7.4 95%CI 1.7-9.4), pneumonia (OR 5.6 95%CI 1.4-11.3), and failing non-operative management (OR 2.4 95%CI 1.3-6.7).

CONCLUSION

The AAST EGS grade can be assigned with ease at any surgical facility using operative or imaging findings. The AAST ASBO severity grading system has predictive validity for important clinical outcomes and allows for standardization across institutions, providers, and future research. Disease severity and outcomes varied between countries.

LEVEL OF EVIDENCE III

Study type Retrospective multi-institutional cohort study.

Small Bowel Obstruction

Identifying patients with small bowel obstruction who need operative intervention and those who will fail nonoperative management is a challenge. Without indications for urgent intervention, a computed tomography scan with/without intravenous contrast should be obtained to identify location, grade, and etiology of the obstruction. Most small bowel obstructions resolve with nonoperative management. Open and laparoscopic operative management are acceptable approaches. Malnutrition needs to be identified early and managed, especially if the patient is to undergo operative management. Confounding conditions include age greater than 65, post Roux-en-Y gastric bypass, inflammatory bowel disease, malignancy, virgin abdomen, pregnancy, hernia, and early postoperative state.

A Shared Decision Approach to Chronic Abdominal Pain Based on Cine-MRI: A Prospective Cohort Study

OBJECTIVES

Chronic abdominal pain develops in 11-20% of patients undergoing abdominal surgery, partly owing to post-operative adhesions. In this study we evaluate results of a novel diagnostic and therapeutic approach for pain associated with adhesions.

METHODS

Prospective cohort study including patients with a history of abdominal surgery referred to the outpatient clinic of a tertiary referral center for the evaluation of chronic abdominal pain. Subgroups were made based on outcome of adhesion mapping with cine-MRI and shared decision making. In operatively managed cases, anti-adhesion barriers were applied after adhesiolysis. Long-term results for pain were evaluated by a questionnaire.

RESULTS

A total of 106 patients were recruited. Seventy-nine patients had adhesions on cine-MRI, 45 of whom underwent an operation. Response rate to follow-up questionnaire was 86.8%. In the operative group (Group 1), the number of negative laparoscopies was 3 (6%). After a median of 19 (range 6-47) months follow-up, 80.0% of patients in group 1 reported improvement of pain, compared with 42.9% in patients with adhesions on cine-MRI who declined surgery (group 2), and 26.3% in patients with no adhesions on cine-MRI (group 3), P = 0.002. Consultation of medical specialists was significantly lower in group 1 compared with groups 2 and 3 (35.7 vs. 65.2 vs. 58.8%; P = 0.023).

CONCLUSION

We demonstrate long-term pain relief in two-thirds of patients with chronic pain likely caused by adhesions, using cine-MRI and a shared decision-making process. Long-term improvement of pain was achieved in 80% of patients who underwent surgery with concurrent application of an anti-adhesion barrier.

Managing Adhesive Small Bowel Obstruction with Water-Soluble Contrast Should Be Protocolized: A Retrospective Analysis

Aim  Current literature emphasizes the effectiveness of computed tomography (CT) and water-soluble contrast agent, Gastrografin, in the investigation of adhesive small bowel obstruction (ASBO). As there is no management protocol for ASBO at our institution, the aim of this study was to determine the effect of imaging methods—CT, Gastrografin challenge (GC), or plain-film X-ray—on patient outcomes in a clinical setting.

Methods  All 163 emergency presentations of ASBO during the study period between December 2010 and September 2012 were collected retrospectively. Cases were divided into three groups: CT with oral contrast, GC, or plain-film X-ray only. The primary outcome was time to theater.

Results  Patients investigated with X-ray only were significantly less likely to require surgery (6% in plain-film X-ray vs. 35% and 20% in CT and GC, respectively; p  = 0.003). In cases requiring surgery, GC was associated with a 24-hour longer time to imaging than CT ( p  < 0.001). The time to theater was 71:25 hours for GC versus 46:39 for CT ( p  = 0.039). There was no significant difference in bowel resection or complication rates.

Conclusion  Patients undergoing water-soluble contrast studies were subjected to unnecessary delays in their clinical course. These delays are costly and avoidable. The development and implementation of an evidence-based protocol for the management of small bowel obstruction is strongly recommended. The lack of a protocol likely caused significant delays in Gastrografin administration, reducing its known benefits for clinical decision-making and length of stay.

Bologna guidelines for diagnosis and management of adhesive small bowel obstruction (ASBO): 2017 update of the evidence-based guidelines from the world society of emergency surgery ASBO working group

Background

Adhesive small bowel obstruction (ASBO) is a common surgical emergency, causing high morbidity and even some mortality. The adhesions causing such bowel obstructions are typically the footprints of previous abdominal surgical procedures. The present paper presents a revised version of the Bologna guidelines to evidence-based diagnosis and treatment of ASBO. The working group has added paragraphs on prevention of ASBO and special patient groups.

Methods

The guideline was written under the auspices of the World Society of Emergency Surgery by the ASBO working group. A systematic literature search was performed prior to the update of the guidelines to identify relevant new papers on epidemiology, diagnosis, and treatment of ASBO. Literature was critically appraised according to an evidence-based guideline development method. Final recommendations were approved by the workgroup, taking into account the level of evidence of the conclusion.

Recommendations

Adhesion formation might be reduced by minimally invasive surgical techniques and the use of adhesion barriers. Non-operative treatment is effective in most patients with ASBO. Contraindications for non-operative treatment include peritonitis, strangulation, and ischemia. When the adhesive etiology of obstruction is unsure, or when contraindications for non-operative management might be present, CT is the diagnostic technique of choice. The principles of non-operative treatment are nil per os, naso-gastric, or long-tube decompression, and intravenous supplementation with fluids and electrolytes. When operative treatment is required, a laparoscopic approach may be beneficial for selected cases of simple ASBO.Younger patients have a higher lifetime risk for recurrent ASBO and might therefore benefit from application of adhesion barriers as both primary and secondary prevention.

Discussion

This guideline presents recommendations that can be used by surgeons who treat patients with ASBO. Scientific evidence for some aspects of ASBO management is scarce, in particular aspects relating to special patient groups. Results of a randomized trial of laparoscopic versus open surgery for ASBO are awaited.

Modified Paul-Mikulicz jejunostomy in frail geriatric patients undergoing emergency small bowel resection

BACKGROUND

Proximal or extended bowel resections are sometimes necessary during emergency surgery of the small bowel and call for creating a high small bowel stomy as a part of damage control surgery. Secondary restoration of intestinal continuity in the frail geriatric patient, further weakened by subsequent severe malabsorption may be prohibitive.

METHODS

Six patients underwent emergency small bowel resection for proximal jejunal disease (83.3% high-grade adhesive SBO and 16.7% jejunal diverticulitis complicated with perforation). With the intention to avoid end jejunostomy and the need for repeat laparotomy for bowel continuity restoration we modified the classic Paul-Mikulicz jejunostomy.

RESULTS

The postoperative course was uneventful in four patients whose general condition improved considerably. At six-month follow-up, neither patients required parenteral nutrition.

CONCLUSIONS

This modified stoma can have the advantage of allowing a partial passage of the enteric contents, reducing the degree of malabsorption, and rendering jejunostomy reversal easy to perform later.

Current management of adhesive small bowel obstruction

Small bowel obstruction is a common and significant surgical presentation. Approximately 30% of presentations will require surgery during admission. The great challenge of adhesive small bowel obstruction (ASBO) management is the early detection of silent intestinal ischaemia in patients initially deemed suitable for conservative therapy. Recent literature emphasizes the effectiveness of computed tomography enterography and water-soluble contrast studies in the management of ASBO. Low-volume undiluted water-soluble contrast has been shown to have both triage and therapeutic value in the management of ASBO. Their use has been demonstrated to reduce the need for surgery to below 20%. There has also been growing interest in clinicoradiological algorithms which aim to predict ischaemia early in the course of presentation. The aim of this review is to summarize the latest evidence and clarify previous uncertainties, specifically regarding the duration of conservative treatment, timing of contrast studies and the reliability of predictive algorithms. Based on this latest evidence, we have formulated a management protocol which aims to integrate these latest developments and formalize a strategy for best management in ASBO.

Which patients with intestinal obstruction need surgery? The delta neutrophil index as an early predictive marker

Purpose

Predicting the need for surgical intervention among patients with intestinal obstruction is challenging. The delta neutrophil index (DNI) has been suggested as a useful marker of immature granulocytes, which indicate an infection or sepsis. In this study, we evaluated the impact of the DNI as an early predictor of operation among patients with intestinal obstruction.

Methods

A total of 171 patients who were diagnosed with postoperative intestinal obstruction were enrolled in this study. Medical records, including data for the initial CRP level, WBC count, and DNI were reviewed. Receiver operating characteristic (ROC) curves were generated to clarify the optimal DNI cutoff values for predicting an operation.

Results

Among the 171 patients, 38 (22.2%) needed surgical intervention. The areas under the initial CRP, WBC, and DNI ROC curves were 0.460, 0.449, and 0.543, respectively. The optimal cutoff value for predicting further surgical intervention according to the initial DNI level was 4.3%. The accuracy of the cutoff value was 74.9%, the sensitivity was 23.7%, and the specificity was 89.5% (positive predictive value, 23.7%; negative predictive value, 89.5%). In the multivariate analysis, initial DNI levels ≥ 4.3% were significantly associated with surgical intervention (odd ratio, 3.092; 95% confidence interval, 1.072–8.918; P = 0.037).

Conclusion

The initial DNI level in patients with intestinal obstruction may be a useful predictor for determining the need for surgical intervention.

Value of gastrografin in adhesive small bowel obstruction

BACKGROUND

Small bowel obstruction (SBO) from adhesive disease presents great burden for the healthcare system. Some groups have reported water soluble contrast agents (WSCA) protocols, but published studies are underpowered. This study introduces a WSCA protocol to improve outcomes and streamline patient care.

STUDY DESIGN

The study ran July 1, 2013-June 30, 2015, at Kaiser Permanente San Diego; protocol started July 1, 2014. Data was collected prospectively, on an intention to treat basis. We excluded patients whose SBO were not due to adhesive disease. Protocol included nasogastric tube, intravenous resuscitation, liquid docusate, and gastrografin study if symptoms persisted at 24 h. Colon contrast determined resolution vs operative consideration. Primary outcomes were operative rates and hospital length of stay (LOS).

RESULTS

Seven hundred fifteen were patients admitted with SBO; after exclusions there were 261 pre-protocol and 243 protocol patients. One hundred sixty patients resolved within 24 h; 96% of remaining patients stayed on protocol (n = 154). After WSCA protocol began, 15.6% required an operation, compared to 19.8% of pre-protocol patients (NS). The WSCA protocol significantly decreased the time to surgery (2.8 vs 4.88 days, p = 0.03), and the LOS of operated patients (9.51 vs 15.78 days, p = 0.02).

CONCLUSIONS

A standardized SBO protocol using WSCA significantly decreased time to operation and hospital LOS. This approach improves utilization of resources and may improve outcomes. More work should be done to investigate the positive effects of WSCA protocol for patients with SBO.

Assessment of Strangulation in Adhesive Small Bowel Obstruction on the Basis of Combined CT Findings: Implications for Clinical Care

Purpose To determine which computed tomography (CT) findings or combinations of findings can help to accurately identify strangulation in adhesive small bowel obstruction (SBO). Materials and Methods Contrast agent-enhanced CT findings in a cohort of 256 patients consecutively admitted for adhesive SBO, with a delay of less than 24 hours between CT and surgery for the operated patients, were reviewed independently by two radiologists, with consensus by a third, to assess CT findings commonly associated with strangulation. The reference standard for strangulation was surgery. Univariate and multivariate analyses were performed to identify predictors of strangulation in the entire cohort and to identify predictors of the need for surgical resection in the subgroup of patients with strangulation. A CT score was obtained and diagnostic performances of different combined CT findings were calculated. Results In this study, 105 patients (41.0%; 105 of 256) underwent a surgical procedure, 62 of whom were found to have strangulation (59.0%; 62 of 105), whereas 151 patients (59.0%; 151 of 256) improved with medical care. Three CT findings were significantly associated with strangulation in the multivariate analysis: reduced bowel wall enhancement (odds ratio, 7.8; 95% confidence interval [CI]: 2.6, 23.5), diffuse mesenteric haziness (odds ratio, 6.1; 95% CI: 2.5, 15.2), and a closed-loop mechanism (odds ratio, 6.5; 95% CI: 2.8, 15.5). The model combining these three features had an area under the curve of 0.91 (95% CI: 0.86, 0.96) and a high negative predictive value (97%; 95% CI: 93%, 99%). Positive likelihood ratios were high when two or three of these CT findings were combined (positive likelihood ratios, 14.7 [95% CI: 7.1, 30.4] and 43.8 (95% CI: 14.2, 135.2], respectively). Among the strangulated cases, reduced bowel wall enhancement (odds ratio, 3.9; 95% CI: 1.3, 12) and mesenteric fluid (odds ratio, 3.6; 95% CI: 1.0, 12.8) were predictive of resection. Conclusion A score that combines three CT findings (reduced bowel wall enhancement, a closed-loop mechanism, and diffuse mesenteric haziness) can accurately predict strangulation in adhesive SBO. ^© RSNA, 2017 Online supplemental material is available for this article.

High-Density Free Fluid on Computed Tomography: a Predictor of Surgical Intervention in Patients with Adhesive Small Bowel Obstruction

BACKGROUND

Patients with adhesive small bowel obstruction (ASBO) often develop intraabdominal free fluid (IFF). While IFF is a finding on abdominopelvic computed tomography (CT) associated with the need for surgical intervention, many patients with IFF can be still managed non-operatively. A previous study suggested that a higher red blood cell count of IFF is highly predictive of strangulated ASBO. We hypothesized that radiodensity in IFF (Hounsfield unit (HU)) on CT would predict the need for surgical intervention.

STUDY DESIGN

Patients with clinicoradiological evidence of ASBO between January 2009 and December 2013 were identified. In patients with IFF > 3 cm² identified on CT, the HU was measured in the largest pocket of IFF. A sensitivity analysis was performed to determine a high-density HU threshold. The HU of patients who underwent therapeutic laparotomy was compared with those successfully discharged with non-operative management.

RESULTS

A total of 318 patients with ASBO (median age 52 years, 56.0 % male) were identified. Of 111 patients who had IFF on CT, 55.9 % underwent therapeutic laparotomy and 15.3 % required bowel resection. Radiodensity of IFF in the operative group was significantly higher than that in the non-operative group (18.2 vs. 7.0 HU, p < 0.01). Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of high-density IFF (>10 HU) to predict the need for surgical intervention were 83.9, 65.3, 75.4, 76.2, and 75.6 %, respectively.

CONCLUSIONS

High-density IFF on CT was significantly associated with the need for surgical intervention in patients with ASBO. Prospective study to validate the predictive value of high-density IFF on CT will be warranted.