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

Diagnostic accuracy of computed tomography findings for hollow viscus injuries following thoracoabdominal gunshot wounds

BACKGROUND

Selective nonoperative management (SNOM) of abdominal gunshot wounds (GSWs) is increasingly used as computed tomography (CT) has become a diagnostic adjunct for the evaluation of intraabdominal injuries including hollow viscus injuries (HVIs). Currently, there is scarce data on the diagnostic accuracy of CT for identifying HVI. The purpose of this study was to determine the diagnostic accuracy of different CT findings in the diagnosis of HVI following abdominal GSW.

METHODS

This retrospective single-center cohort study was performed from January 2015 to April 2019. We included consecutive patients (≥18 years) with abdominal GSW for whom SNOM was attempted and an abdominal CT was obtained as a part of SNOM. Computed tomography findings including abdominal free fluid, diffuse abdominal free air, focal gastrointestinal wall thickness, wall irregularity, abnormal wall enhancement, fat stranding, and mural defect were used as our index tests. Outcomes were determined by the presence of HVI during laparotomy and test performance characteristics were analyzed.

RESULTS

Among the 212 patients included for final analysis (median age: 28 years), 43 patients (20.3%) underwent a laparotomy with HVI confirmed intraoperatively whereas 169 patients (79.7%) were characterized as not having HVI. The sensitivity of abdominal free fluid was 100% (95% confidence interval [CI]: 92-100). The finding of a mural defect had a high specificity (99%, 95% CI: 97-100). Other findings with high specificity were abnormal wall enhancement (97%, 95% CI: 93-99) and wall irregularity (96%, 95% CI: 92-99).

CONCLUSION

While there was no singular CT finding that confirmed the diagnosis of HVI following abdominal GSW, the absence of intraabdominal free fluid could be used to rule out HVI. In addition, the presence of a mural defect, abnormal wall enhancement, or wall irregularity is considered as a strong predictor of HVI.

LEVEL OF EVIDENCE

Diagnostic Test or Criteria; Level II.

Prediction model for irreversible intestinal ischemia in strangulated bowel obstruction

Background

Preoperatively diagnosing irreversible intestinal ischemia in patients with strangulated bowel obstruction is difficult. Therefore, this study aimed to establish a prediction model for irreversible intestinal ischemia in strangulated bowel obstruction.

Methods

We included 83 patients who underwent emergency surgery for strangulated bowel obstruction between January 2014 and March 2022. The predictors of irreversible intestinal ischemia in strangulated bowel obstruction were identified using logistic regression analysis, and a prediction model for irreversible intestinal ischemia in strangulated bowel obstruction was established using the regression coefficients. Receiver operating characteristic analysis and fivefold cross-validation was used to assess the model.

Results

The prediction model (range, 0–4) was established using a white blood cell count of ≥ 12,000/µL and the computed tomography value of peritoneal fluid that was ≥ 20 Hounsfield units. The areas of the receiver operating characteristic curve of the new prediction model were 0.814 and 0.807 after fivefold cross-validation. A score of ≥ 2 was strongly suggestive of irreversible intestinal ischemia in strangulated bowel obstruction and necessitated bowel resection (odds ratio = 15.938). The bowel resection rates for the prediction scores of 0, 2, and 4 were 15.2%, 66.7%, and 85.0%, respectively.

Conclusion

Our model may help predict irreversible intestinal ischemia that necessitates bowel resection for strangulated bowel obstruction cases and thus enable surgeons to recognize the severity of the situation, prepare for deterioration of patients with progression of intestinal ischemia, and select the appropriate surgical procedure for treatment.

Análisis clínico-tomográfico en obstrucción de intestino delgado por adherencias según el sitio de obstrucción en la tomografía

Introducción. Las adherencias postoperatorias son la causa más frecuente de obstrucción de intestino delgado. La clínica sugiere el diagnóstico, pero de manera poco precisa la causa y el sitio de la obstrucción. La tomografía computarizada contrastada es el estudio óptimo y permite identificar de manera oportuna a los pacientes que requieren intervención quirúrgica. El objetivo de este estudio fue analizar la correlación entre la clínica y el sitio de obstrucción detectado en la tomografía computarizada contrastada de abdomen, en pacientes con sospecha diagnóstica de obstrucción de intestino delgado por adherencias. Métodos. Estudio prospectivo, transversal y analítico de pacientes con sospecha clínica de obstrucción de intestino delgado por adherencias y antecedentes quirúrgicos y su correlación con el sitio de obstrucción detectado en la tomografía computarizada de abdomen contrastada, de pacientes atendidos entre marzo de 2016 y febrero de 2019 en un hospital de segundo nivel. Resultados. Se incluyeron 41 pacientes, la media de edad fue de 59 años y el género masculino el más comprometido (68,3 %, n=28); la ausencia de evacuaciones estuvo presente en 97,5 % (p=0,026). La tomografía computarizada contrastada mostró el sitio de obstrucción en 73 % de los pacientes y la localización de la obstrucción más prevalente fue en íleon distal (31,7 %, n=13). Se asoció a leucocitosis (p=0,041) y a dolor más intenso (p=0,049), sin presentar irritación peritoneal. Conclusión. La obstrucción localizada en el íleon distal se caracterizó por presentar más dolor y mayor recuento leucocitario, sin correlación como factor de riesgo para requerir tratamiento quirúrgico.

Imaging Modalities for Evaluation of Intestinal Obstruction

It is essential for the colon and rectal surgeon to understand the evaluation and management of patients with both small and large bowel obstructions. Computed tomography is usually the most appropriate and accurate diagnostic imaging modality for most suspected bowel obstructions. Additional commonly used imaging modalities include plain radiographs and contrast imaging/fluoroscopy, while less commonly utilized imaging modalities include ultrasonography and magnetic resonance imaging. Regardless of the imaging modality used, interpretation of imaging should involve a systematic, methodological approach to ensure diagnostic accuracy.

A novel discriminant formula for the prompt diagnosis of strangulated bowel obstruction

PURPOSES

The diagnosis of strangulated bowel obstruction (SBO) is sometimes difficult. We attempted to create and verify a discriminant formula for use as a diagnostic aid for the early diagnosis of SBO.

METHODS

This retrospective study included 97 patients who underwent an operation for SBO from January 2007 to September 2018. First, a discriminant analysis was performed for 73 patients who underwent an operation from January 2007 to December 2015 in order to obtain a formula. Next, we analyzed 34 patients who underwent an operation from January 2016 to September 2018 to verify the formula.

RESULTS

The risk factors for SBO included ascites, signs of preperitoneal irritation, and lactate > 1.16 mmol/L. The discriminant formula is as follows: 1.954 × collection of ascites (1 or 0) + 1.239 × peritoneal irritation sign (1 or 0) + 0.378 × lactate - 2.331 (1: positive, 0: negative). The predictive value was as follows: sensitivity, 87.5%; specificity, 64.7%; and predictive accuracy, 73.5%. In patients who presented within 24 h of the onset, the sensitivity was 92.3%, the specificity was 75.0%, and the predictive accuracy was 85.7%.

CONCLUSION

Our discriminant formula seems useful for the rapid diagnosis of SBO.

Diagnosis of single adhesive bands versus matted adhesions in small bowel obstructions: a radiological predictive score

PURPOSE

The objective was to develop a radiological score obtained from multi-detector computed tomography (MDCT) to differentiate between single band adhesion (SBA) and matted adhesions (MA) as the etiology of small bowel obstruction (SBO).

METHODS

All consecutive patients who underwent surgery from January 2013 to June 2018 for adhesion-induced SBO were retrospectively included.

RESULTS

Among the 193 patients having surgery for SBO, 119 (61.6%) had SBA and 74 (38.4%) had MA surgically proven. In multivariate analysis, the presence of a beak sign (OR = 3.47, CI [1.26; 9.53], p = 0.02), a closed loop (OR = 11.37, CI [1.84; 70.39], p = 0.009), focal mesenteric haziness (OR = 3.71, CI [1.33; 10.34], p = 0.01) and focal and diffuse peritoneal fluid (OR = 4.30, CI [1.45; 12.73], p = 0.009 and OR = 6.34, CI [1.77; 22.59], p = 0.004, respectively) were significantly associated with SBA. Conversely, the presence of diffuse mesenteric fluid without focal fluid (OR = 0.23, CI [0.06; 0.92], p = 0.04) and an increase of the diameter of the most dilated loop (OR = 0.94, CI [0.90; 0.99], p = 0.02) were inversely associated with SBA. Using the significant predictive factors of SBA, we built a composite score to radiologically predict the etiology of SBO. The area under the receiver operating characteristic (ROC) curve of the score was 0.8274. For a cut-off score of -0.523, sensitivity, specificity and the percentage of patients correctly classified were 78.4%, 84.6% and 80%, respectively. If the score is ≥ 7, the probability that the mechanism of SBO is not SBA was 100%.

CONCLUSIONS

The present score, validated in a different population, could be a significant tool in the decision for surgical management.

Predicting Intestinal Ischaemia in Patients with Adhesive Small Bowel Obstruction: A Simple Score

BACKGROUND/AIMS

Intestinal ischaemia (II) is the most critical factor to determine in patients with adhesive small bowel obstruction (ASBO) because intestinal ischaemia could be reversible. The aim of this study was to create a clinicoradiological score to predict II in patients with ASBO.

METHODS

We conducted a retrospective study including 124 patients with ASBO. Logistic regression analysis was used to identify predictive factors of II. We assigned points for the score according to the regression coefficient. The area under the curve (AUC) was determined using receiver operating characteristic curves.

RESULTS

Six independent predictive factors of II were identified: age, pain duration, body temperature, WBC, reduced wall enhancement and segmental mesenteric fluid at CT scan. According to the regression, coefficient points were assigned to each of the variables associated with II. The estimated rates of II were calculated for the total scores ranging from 0 to 24. The AUC of this clinicoradiological score was 0.92. A cut-off score of 6 was used for the low-probability group (the risk of II was 1.13%). A score ranging from 7 to 15 defined intermediate-probability group (the risk of II was 44%). A score ≥16 defined high-probability group (100% of patients in this group had II).

CONCLUSIONS

We performed a score to predict the risk of intestinal II with a good accuracy (the AUC of our score exceeded 0.90). This score is reliable and reproducible, so it can help surgeon to prioritize patients with II for surgery because ischaemia could be reversible, avoiding thus intestinal necrosis.

Diagnostic utility of CT for small bowel obstruction: Systematic review and meta-analysis

BACKGROUND

To perform a systematic review and meta-analysis evaluating the diagnostic performance of computed tomography (CT) for small bowel obstruction (SBO), including diagnostic accuracy, ischemia, predicting surgical intervention, etiology and transition point.

METHODS

PubMed/MEDLINE and related databases were searched for research articles published from their inception through August 2018. Findings were pooled using bivariate random-effects and summary receiver operating characteristic curve models. Meta-regression and subgroup analyses were performed to evaluate whether publication year, patient age, enhanced CT, slice thickness and pathogenesis affected classification accuracy.

RESULTS

In total, 45 studies with a total of 4004 patients were included in the analysis. The pooled sensitivity and specificity of CT for SBO were 91% (95% confidence interval [CI]: 84%, 95%) and 89% (95% CI: 81%, 94%), respectively, and there were no differences in the subgroup analyses of age, publication year, enhanced CT and slice thickness. For ischemia, the pooled sensitivity and specificity was 82% (95% CI: 67%, 91%) and 92% (95% CI: 86%, 95%), respectively. No difference was found between enhanced and unenhanced CT based on subgroup analysis; however, high sensitivity was found in adhesive SBO compared with routine causes (96% vs. 78%, P = 0.03). The pooled sensitivity and specificity for predicting surgical intervention were 87% and 73%, respectively. The accuracy for etiology of adhesions, hernia and tumor was 95%, 70% and 82%, respectively. In addition, the pooled sensitivity and specificity for transition point was 92% and 77%, respectively.

CONCLUSIONS

CT has considerable accuracy in diagnosis of SBO, ischemia, predicting surgical intervention, etiology and transition point.

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.

Clinical factors associated with intestinal strangulating obstruction and recurrence in adhesive small bowel obstruction: A retrospective study of 288 cases

Postoperative adhesions are a common cause of adhesive small bowel obstruction (ASBO), and recognition of intestinal strangulation is important. The aim of this study is to analyze the clinical factors for strangulating obstruction and to identify the predictors for recurrence of ASBO.A retrospective study was conducted using the database in our department. Patients with ASBO from January 2013 to April 2016 were included in the study and were subject to follow-up. The clinical factors associated with strangulating obstruction and recurrence after treatment were analyzed by using univariate and multivariate logistic regression model.In total, 288 ASBO patients were included in the study. Of these, 37 (12.9%) patients had occurred strangulating obstructions, and 251 (87.1%) patients had simple obstructions. Four clinical parameters, including increasing heart rate (>100 bpm), increasing WBC count (>15 × 10/L), CT findings of thickening or swelling of the mesentery, and CT showing seroperitoneum were detected as independent clinical factors for intestinal strangulation. Eighty-four (29.2%) patients experienced recurrence of obstruction during the median 24 months of follow-up. Recurrence rates were reduced in patients who underwent surgical treatment compared with those who received conservative management [21.3% (26/122) vs 34.9% (58/166) (P = .010)]. Nevertheless, the recurrence rates were not significantly increased in patients with strangulating obstructions compared with those with simple ASBO [34.3% (12/35) vs 27.7% (72/253) (P = .186)].Four clinical parameters including tachycardia, leukocytosis, along with CT findings of thickening or swelling of the mesentery and CT showing seroperitoneum, associated with occurrence of intestinal strangulation in ASBO. ASBO patients who underwent surgical treatment had a reduced recurrence rate, but ASBO patients with strangulating obstructions had not increase the recurrence rates than those of patients with simple ASBO.

A Systematic Review of the Clinical Presentation, Diagnosis, and Treatment of Small Bowel Obstruction

PURPOSE OF REVIEW

This study aimed to systematically review small bowel obstruction (SBO), focusing on recent changes in diagnosis/therapy.

RECENT FINDINGS

SBO incidence is about 350,000/annum in the USA. Etiologies include adhesions (65%), hernias (10%), neoplasms (5%), Crohn's disease (5%), and other (15%). Bowel dilatation occurs proximal to obstruction primarily from swallowed air and secondarily from intraluminal fluid accumulation. Dilatation increases mural tension, decreases mucosal perfusion, causes bacterial proliferation, and decreases mural tensile strength that increases bowel perforation risks. Classical clinical tetrad is abdominal pain, nausea and emesis, abdominal distention, and constipation-to-obstipation. Physical exam may reveal restlessness, acute illness, and signs of dehydration and sepsis, including tachycardia, pyrexia, dry mucous membranes, hypotension/orthostasis, abdominal distention, and hypoactive bowel sounds. Severe direct tenderness, involuntary guarding, abdominal rigidity, and rebound tenderness suggest advanced SBO, as do marked leukocytosis, neutrophilia, bandemia, and lactic acidosis. Differential diagnosis includes postoperative ileus, narcotic bowel, colonic pseudo-obstruction, mesenteric ischemia, and large bowel obstruction. Medical resuscitation includes intravenous hydration, correcting electrolyte abnormalities, intravenous antibiotics, nil per os, and nasoenteral suction. Abdominal CT with oral and intravenous gastrografin contrast is highly sensitive and specific in detecting/characterizing SBO. SBO usually resolves with medical therapy but requires surgery, preferentially by laparoscopy, for unremitting total obstruction, bowel perforation, severe ischemia, or clinical deterioration with medical therapy. Overall mortality is 10% but increases to 30% with bowel necrosis/perforation. Key point in SBO is early diagnosis, emphasizing abdominal CT; aggressive medical therapy including rehydration, antibiotics, and nil per os; and surgery for failed medical therapy.