Usefulness of known computed tomography and clinical criteria for diagnosing strangulation in small-bowel obstruction: analysis of true and false interpretation groups in computed tomography

A novel nomogram integrating body composition and inflammatory-nutritional markers for predicting postoperative complications in patients with adhesive small bowel obstruction

Background

Postoperative complications in adhesive small bowel obstruction (ASBO) significantly escalate healthcare costs and prolong hospital stays. This study endeavors to construct a nomogram that synergizes computed tomography (CT) body composition data with inflammatory-nutritional markers to forecast postoperative complications in ASBO.

Methods

The study's internal cohort consisted of 190 ASBO patients recruited from October 2017 to November 2021, subsequently partitioned into training (n = 133) and internal validation (n = 57) groups at a 7:3 ratio. An additional external cohort comprised 52 patients. Body composition assessments were conducted at the third lumbar vertebral level utilizing CT images. Baseline characteristics alongside systemic inflammatory responses were meticulously documented. Through univariable and multivariable regression analyses, risk factors pertinent to postoperative complications were identified, culminating in the creation of a predictive nomogram. The nomogram's precision was appraised using the concordance index (C-index) and the area under the receiver operating characteristic (ROC) curve.

Results

Postoperative complications were observed in 65 (48.87%), 26 (45.61%), and 22 (42.31%) patients across the three cohorts, respectively. Multivariate analysis revealed that nutrition risk score (NRS), intestinal strangulation, skeletal muscle index (SMI), subcutaneous fat index (SFI), neutrophil-lymphocyte ratio (NLR), and lymphocyte-monocyte ratio (LMR) were independently predictive of postoperative complications. These preoperative indicators were integral to the nomogram's formulation. The model, amalgamating body composition and inflammatory-nutritional indices, demonstrated superior performance: the internal training set exhibited a 0.878 AUC (95% CI, 0.802-0.954), 0.755 accuracy, and 0.625 sensitivity; the internal validation set displayed a 0.831 AUC (95% CI, 0.675-0.986), 0.818 accuracy, and 0.812 sensitivity. In the external cohort, the model yielded an AUC of 0.886 (95% CI, 0.799-0.974), 0.808 accuracy, and 0.909 sensitivity. Calibration curves affirmed a strong concordance between predicted outcomes and actual events. Decision curve analysis substantiated that the model could confer benefits on patients with ASBO.

Conclusion

A rigorously developed and validated nomogram that incorporates body composition and inflammatory-nutritional indices proves to be a valuable tool for anticipating postoperative complications in ASBO patients, thus facilitating enhanced clinical decision-making.

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.

[Preoperative diagnosis of intestinal ischemia in small bowel obstruction. Only computed tomography? A multiple-center observational study]

OBJECTIVE

To evaluate the accuracy of clinical, laboratory and instrumental methods for diagnosis of intestinal ischemia following small bowel obstruction in emergency hospitals.

MATERIAL AND METHODS

Multiple-center observational retrospective study enrolled 158 consecutive patients with benign small bowel obstruction (SBO) treated at four hospitals between May 2017 and December 2019. The role of clinical, laboratory and instrumental diagnostic methods for intestinal ischemia was analyzed. We assessed the impact of CT and contrast-enhanced X-ray examination on survival of patients.

RESULTS

Laboratory parameters as criteria of ischemia following SBO were similar (leukocytosis >14·10⁹/l (p=1.0), serum lactate >2.0 mmol/l (p=0.28), heart rate >90/min (p=0.71) and fever (p=0.74)). The only laboratory indicator with significant differences was serum sodium. Decrease in leukocytosis over time was less common in patients with ischemia (25% vs. 61.3%, p=0.012). Univariate Kaplan-Meier analysis did not establish the effect of CT on survival (7.8% [95% CI 7.6-8.0] vs. 6.5% [95% CI 6.3-6.6], p=0.786). Logistic regression revealed 6.4-fold higher chance of accurate diagnosis (ischemia/non-ischemia) in case of CT-based conclusion of ischemia (95% CI 0.025-0.85). Univariate analysis showed that the use of water-soluble contrast for adhesive SBO was associated with lower mortality (4.1% [95% CI 4.0-4.2] vs. 14.3% [95% CI 13.7-14.9], p=0.032) without assessing the comparability of groups.

CONCLUSION

Routine laboratory tests were not specific for intestinal ischemia. Therefore, they should not be considered as the only criteria for surgical tactics in intestinal obstruction. Only CT showed acceptable diagnostic accuracy, and, apparently, only this method has real prospects for improving the quality of diagnosis due to technical support, training of surgeons and specialists for diagnosis.

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.

Small bowel obstruction after caesarean section: Laparoscopic management. Two case reports

Introduction

Caesarean section is the most common abdominal surgery performed on women worldwide. Adhesions represent a severe complication of cesarean section and can cause different degrees of bowel obstruction.

Case reports

We report two unusual cases of small bowel obstruction treated with laparoscopic approach after caesarean section performed for gynecological pathologies. In the first one small bowel obstruction was due to volvulus caused by a severe pelvic adhesion syndrome; in the second one, occlusive picture was related to presence of multiple adhesion phenomena between the sigmoid colon and the right ovary as result of abdominal hysterectomy.

Discussion

The incidence of small bowel obstruction after caesarean section is very low and postoperative adhesions represent the main cause. Diagnosis was established by clinical signs, radiological and intraoperative findings. Laparoscopic approach can be the treatment of choice only in selected patients. In presence of dense adhesions, inability to visualize the site of obstruction, iatrogenic intestinal perforation, bowel necrosis and technical difficulties, conversion to open surgery is mandatory.

Conclusion

In selected patients with small bowel obstruction laparoscopy is a safe and feasible procedure if conservative measures fail.

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.

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.

Adhesive Closed-loop Small Bowel Obstruction

Complete small bowel obstruction (SBO) is a common surgical emergency often resulting from adhesive bands that form following iatrogenic peritoneal injury. Rarely, adhesive SBO may arise without previous intra-abdominal surgery through other modes of peritoneal trauma. We present the case of a male evaluated in the emergency department for a closed-loop small bowel obstruction due to an adhesive band that likely formed after blunt abdominal trauma over two decades earlier. We review the epidemiology, pathophysiology, and treatment options for similar cases of adhesive SBO.

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.

A Prediction Model for Recognizing Strangulated Small Bowel Obstruction

Introduction

Early and accurate diagnosis of strangulated small bowel obstruction (SSBO) is difficult. This study aimed to devise a prediction model for predicting the risk of SSBO.

Materials and Methods

A database of 417 patients who had clinical symptoms of intestinal obstruction confirmed by computed tomography (CT) were evaluated for inclusion in this study. Symptoms and laboratory and radiologic findings of these patients were collected after admission. These clinical factors were analyzed using logistic regression. A logistic regression model was applied to identify determinant variables and construct a clinical score that would predict SSBO.

Results

Seventy-six patients were confirmed to have SSBO, 169 patients required surgery but had no evidence of intestinal ischemia, and 172 patients were successfully managed conservatively. In multivariate logistic regression analysis, body temperature ≥ 38.0°C, positive peritoneal irritation sign, white blood cell (WBC) count > 10.0 × 10^9/L, thick-walled small bowel ≥3 mm, and ascites were significantly associated with SSBO. A new prediction model with total scores ranging from 0 to 481 was developed with these five variables. The area under the curve (AUC) of the new prediction model was 0.935.

Conclusions

Our prediction model is a good predictive model to evaluate the severity of SBO.

The use of delta neutrophil index and myeloperoxidase index as diagnostic predictors of strangulated mechanical bowel obstruction in the emergency department

Early detection of bowel strangulation is difficult in patients with mechanical bowel obstruction (MBO). There have been no previous reports of predicting strangulation in MBO cases using the delta neutrophil index (DNI), which is a measure of the proportion of circulating immature granulocytes, or the myeloperoxidase index (MPXI), which is a measure of serum myeloperoxidase level. Therefore, we evaluated differences in initial DNI and MPXI upon presentation at the emergency department (ED) according to strangulation presence in MBO patients.This is a retrospective observational study of consecutive patients older than 18 years who were diagnosed with MBO over a 31-month period. MBO was ultimately confirmed by computed tomography (CT) findings by a radiology specialist. Patients were categorized by a strangulation group (SG) and nonstrangulation group (NSG). The SG was defined by surgical and pathologic findings after the surgical operation. Initial serum counts of white blood cells and neutrophils, C-reactive protein levels, and DNI and MPXI scores were investigated in the ED.Fifteen of 160 patients were allocated to the SG (9.4%), and among the inflammatory markers, median initial DNI value was the only one that was significantly higher in the SG (0% vs 3.2%, P = 0.003). Although the areas under the receiver operation characteristic (ROC) curves for initial DNI and CT for differentiating strangulated from nonstrangulated bowel obstruction were 0.713 (95% confidence interval [CI]: 0.636-0.782) and 0.883 (95% CI: 0.823-0.928), respectively; there was no significant difference between DNI and CT (P = 0.147). The area under the curve (AUC) for predicting strangulated bowel disease from a combination of initial DNI score and CT findings (0.983, 95% CI: 0.948-0.997) was higher than the AUC for CT alone, although the difference was not significant (P = 0.052).In conclusion, initial DNI, which was performed in the ED, was found to be significantly higher in the SG than in the NSG. Initial DNI might be a useful additional parameter for improving the prediction accuracy of CT.

Chylous ascites associated with intestinal obstruction from volvulus due to Petersen's hernia: report of a case

Background

Chylous ascites is an uncommon finding which is usually associated with recent abdominal/oncologic or retroperitoneal surgery. It is not usually seen in cases of acute obstruction.

Case presentation

A patient who had previously undergone a laparoscopy-assisted distal gastrectomy with Roux-en-Y reconstruction for early gastric cancer presented with acute abdominal pain and epigastric fullness. Computed tomography suggested small bowel obstruction due to volvulus. We were able to reduce the volvulus and close a Petersen’s hernia without resecting the bowel; a large amount of chylous ascites was an incidental finding.

Conclusions

We present a case of chylous ascites occurring in a setting of small bowel obstruction due to Petersen’s hernia, 3 years after successful distal gastrectomy for early gastric cancer, with no evidence of tumor recurrence.

The Combination of D-Dimer and Peritoneal Irritation Signs as a Potential Indicator to Exclude the Diagnosis of Intestinal Necrosis

Intestinal necrosis is a life-threatening disease, and its prompt and accurate diagnosis is very important. This study aimed to evaluate the value of D-dimer as a marker for early diagnosis of bowel necrosis. From 2009 to 2013, patients undergoing operation due to acute intestinal obstruction were retrospectively analyzed. Clinicopathologic characteristics were compared among no ischemia group, reversible ischemia group, and bowel necrosis group. There were totally 274 patients being included for analyses. Patients with bowel necrosis had a significant highest level of D-dimer compared with other 2 groups (P =  .007) when FEU unit was applied. The optimal cutoff value of D-dimer levels as an indicator in diagnosing bowel necrosis was projected to be 1.965 mg/L, which yielded a sensitivity of 84.0%, a specificity of 45.6%, a positive predictive value of 60.7%, and a negative predictive value of 74.0%. And the sensitivity of 84.0% and specificity of 70.0% were detected, when 1.65 mg/L of D-dimer was set as the cutoff value to distinguish the reversible ischemia and bowel necrosis. The corresponding results in patients with no or slight peritoneal irritation signs were 85.2%, 44.7%, 35.4% and 89.5% respectively. The sensitivity and negative predictive value were 96.0% and 91.7%, respectively, when D-dimer and peritoneal irritation signs were combined to perform the parallel analysis. The combination of D-dimer and peritoneal irritation signs could generate a reliable negative predictive value, which is helpful to exclude the diagnosis of intestinal necrosis. However, it should also be proved in well-designed large-scale prospective study.

Value of CT findings to predict surgical ischemia in small bowel obstruction: A systematic review and meta-analysis

PURPOSE

Our aim was to assess the diagnostic performance in determining strangulation in small bowel obstruction (SBO) for five CT findings commonly considered in published small bowel obstruction (SBO) management guidelines.

MATERIALS AND METHODS

Medical databases were searched for "bowel obstruction", "computed tomography", "strangulation", and related terms. Two reviewers independently selected articles for CT findings investigated with surgical or histological reference standards for strangulation. Bivariate random-effects meta-analytical methods were used.

RESULTS

A total of 768 patients, including 205 with strangulation from nine studies, were evaluated. The reduced bowel wall enhancement CT sign had the highest specificity (95 %, CI 75-99), with a positive LR of 11.07 (2.27-53.88) and DOR of 22.86 (4.99-104.61). The mesenteric fluid sign had the highest sensitivity (89 %, CI 75-96) with a negative LR of 0.16 (0.07-0.39) and a DOR of 13.9 (5.73-33.75). The bowel wall thickness had a sensitivity of 48 % (CI 41-54), a specificity of 83 % (CI 74-89), a positive LR of 2.84 (1.83-4.41) and a negative LR of 0.62 (0.53-0.72). The other CT findings had lower diagnostic performance.

CONCLUSION

Two CT findings should be used in clinical practice: reduced enhanced bowel wall is highly predictive of ischemia, and absence of mesenteric fluid is a reliable finding to rule out strangulation.

KEY POINTS

• Reduced bowel wall enhancement on CT increases the probability of strangulation 11-fold. • Absence of mesenteric fluid on CT decreases the probability of strangulation 6-fold. • The clinical reliability of other CT signs is doubtful for predicting strangulation.

Usefulness of intestinal fatty acid-binding protein in predicting strangulated small bowel obstruction

BACKGROUND

The level of intestinal fatty acid-binding protein (I-FABP) is considered to be useful diagnostic markers of small bowel ischemia. The purpose of this retrospective study was to investigate whether the serum I-FABP level is a predictive marker of strangulation in patients with small bowel obstruction (SBO).

METHODS

A total of 37 patients diagnosed with SBO were included in this study. The serum I-FABP levels were retrospectively compared between the patients with strangulation and those with simple obstruction, and cut-off values for the diagnosis of strangulation were calculated using a receiver operating characteristic curve. In addition, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated.

RESULTS

Twenty-one patients were diagnosed with strangulated SBO. The serum I-FABP levels were significantly higher in the patients with strangulation compared with those observed in the patients with simple obstruction (18.5 vs. 1.6 ng/ml p<0.001). Using a cut-off value of 6.5 ng/ml, the sensitivity, specificity, PPV and NPV were 71.4%, 93.8%, 93.8% and 71.4%, respectively. An I-FABP level greater than 6.5 ng/ml was found to be the only independent significant factor for a higher likelihood of strangulated SBO (P =  0.02; odds ratio: 19.826; 95% confidence interval: 2.1560 - 488.300).

CONCLUSIONS

The I-FABP level is a useful marker for discriminating between strangulated SBO and simple SBO in patients with SBO.

Features on MDCT that predict surgery in patients with adhesive-related small bowel obstruction

Purpose

The purpose of this study was to determine the contribution of multidetector-row computed tomography (MDCT) in the management of adhesion-related small bowel obstruction (SBO) and to identify its predictive value for surgery.

Methods

We conducted a retrospective review of 151 patients over a 5-year period with the diagnosis of SBO caused by adhesion. These patients were divided into two groups: surgery (n =  63) and observation group (n =  88). Two radiologists blinded to the outcome of the patients evaluated MDCT images retrospectively, recording the bowel diameter, bowel wall thickness, degree of obstruction, air-fluid level, mesenteric fatty stranding, transitional zone, intraperitoneal fluid, close loop, whirl sign, and faeces sign. Statistical analyses were performed using univariate and multivariable analyses.

Results

Multivariable analysis showed that MDCT demonstrated presence of intraperitoneal fluid (Odds ratio, OR, 4.38), high-grade or complete obstruction (OR, 3.19) and mesenteric fatty stranding (OR, 2.81), and absence of faeces sign (OR, 2.11) were the most significant predictors. When all of the four criteria were used in combination, high sensitivity of 98.4% and specificity of 90.9% were achieved for the prediction for surgery.

Conclusion

MDCT is useful to evaluate adhesion-related SBO and to predict accurately patients who require surgery. Use of the four MDCT features in combination is highly suggestive of the need for early surgical intervention.

Evaluation and management of small-bowel obstruction: an Eastern Association for the Surgery of Trauma practice management guideline

BACKGROUND

Small-bowel obstruction (SBO) represents as many as 16% of surgical admissions and more than 300,000 operations annually in the United States. The optimal strategies for the diagnosis and management of SBO continue to evolve secondary to advances in imaging techniques, critical care, and surgical techniques. This updated systematic literature review was developed by the Eastern Association for the Surgery of Trauma to provide up-to-date evidence-based recommendations for SBO.

METHODS

A search of the National Library of Medicine MEDLINE database was performed using PubMed interface for articles published from 2007 to 2011.

RESULTS

The search identified 53 new articles that were then combined with the 131 studies previously reviewed by the 2007 guidelines. The updated guidelines were then presented at the 2012 annual EAST meeting.

CONCLUSION

Level I evidence now exists to recommend the use of computed tomographic scan, especially multidetector computed tomography with multiplanar reconstructions, in the evaluation of patients with SBO because it can provide incremental clinically relevant information over plains films that may lead to changes in management. Patients with evidence of generalized peritonitis, other evidence of clinical deterioration, such as fever, leukocytosis, tachycardia, metabolic acidosis, and continuous pain, or patients with evidence of ischemia on imaging should undergo timely exploration. The remainder of patients can safely undergo initial nonoperative management for both partial and complete SBO. Water-soluble contrast studies should be considered in patients who do not clinically resolve after 48 to 72 hours for both diagnostic and potential therapeutic purposes. Laparoscopic treatment of SBO has been demonstrated to be a viable alternative to laparotomy in selected cases.

CT findings of small bowel strangulation: the importance of contrast enhancement

The purpose of this study is to illustrate computed tomography (CT) findings suggestive of small bowel strangulation. We have performed the precontrast and postcontrast CT with single and multidetector CT scanners and evaluated the bowel wall changes and mesentery changes and correlated them with the operative findings. The direct CT findings suggestive of small bowel strangulation included high-density bowel wall on precontrast scans; lack of, or diminished contrast enhancement of the involved bowel wall; localized mesenteric fluid accumulation (mesenteric congestion); and localized pneumatosis. The indirect CT signs included C- or U-shaped loops with mesenteric vessels converging toward the obstruction site, ascites, target sign, two adjacent collapsed round loops, and whirl sign. We particularly emphasize the importance of contrast enhancement of bowel mucosa for early diagnosis to differentiate strangulation from a mechanical obstruction without bowel ischemia, and also the importance to differentiate proximal secondary gas-filled dilated small bowel loops from distal primary involved fluid-filled small bowel loops because these two types of small bowel loops are present in the single peritoneal cavity. As early recognition of small bowel strangulation may help improve the patient outcome because the involved bowel loops can be preserved without resection, it is essential to become familiar with the CT signs suggested small bowel obstruction strangulation.

Laparoscopic adhesiolysis: consensus conference guidelines

AIM

Laparoscopic adhesiolysis has been demonstrated to be technically feasible in small bowel obstruction and carries advantages in terms of post-surgical course. The increasing dissemination of laparoscopic surgery in the emergency setting and the lack of concrete evidence in the literature have called for a consensus conference to draw recommendations for clinical practice.

METHODS

A literature search was used to outline the evidence, and a consensus conference was held between experts in the field. A survey of international experts added expertise to the debate. A public jury of surgeons discussed and validated the statements, and the entire process was reviewed by three external experts.

RESULTS

Recommendations concern the diagnostic evaluation, the timing of the operation, the selection of patients, the induction of the pneumoperitoneum, the removal of the cause of obstructions, the criteria for conversion, the use of adhesion-preventing agents, the need for high-technology dissection instruments and behaviour in the case of misdiagnosed hernia or the need for bowel resection.

CONCLUSION

Evidence of this kind of surgery is scanty because of the absence of randomized controlled trials. Nevertheless laparoscopic skills in emergency are widespread. The recommendations given with the consensus process might be a useful tool in the hands of surgeons.

Diagnosis of ischemic small bowel disease by measurement of serum intestinal fatty acid-binding protein in patients with acute abdomen: a multicenter, observer-blinded validation study

BACKGROUND

Intestinal fatty acid-binding protein (I-FABP) is a low-molecular-mass (15 kDa) cytosolic protein found exclusively in the epithelial cells of the small bowel mucosa. We aimed to evaluate the clinical usefulness of serum I-FABP measurement for the diagnosis of ischemic small bowel disease.

METHODS

Patients with a clinical diagnosis of acute abdomen were recruited for this multicenter trial at one university hospital and nine city hospitals over a 13-month period. Serum I-FABP levels were measured in 361 eligible patients by an enzyme-linked immunosorbent assay using a specific monoclonal antibody.

RESULTS

Of the 361 patients, 242 underwent surgery, and small bowel ischemia was diagnosed in 52 patients. The mean serum I-FABP level in the patients with small bowel ischemia was 40.7 ± 117.9 ng/ml, which was significantly higher than that in patients with non-ischemic small bowel disease (5.8 ± 15.6 ng/ml) and those with non-small bowel disease (1.8 ± 1.7 ng/ml). The serum I-FABP cutoff level for the diagnosis of small bowel ischemia was 3.1 ng/ml. Serum I-FABP was more efficient than conventional biochemical markers, in terms of sensitivity and positive and negative predictive values, in the diagnosis of small bowel ischemia. However, its specificity was slightly lower than that of creatinine phosphokinase or lactate dehydrogenase. The positive and negative likelihood ratios of serum I-FABP were 3.01 and 0.29, respectively.

CONCLUSION

Serum I-FABP measurement is a non-invasive method that is potentially useful for the efficient identification of patients with acute abdomen who are at risk of small bowel ischemia.

Strategies for diagnosis and treatment of small bowel obstruction

Small bowel obstruction, which is caused by a variety of etiological factors and mainly manifests as abdominal pain, vomiting and distension, is one of the most common acute abdomens. A rapid and accurate diagnosis of small bowel obstruction is needed to give reasonable and effective treatment to avoid its rapid deterioration. In this paper we discuss the strategies for diagnosis and treatment of small bowel obstruction through comparing different imaging methods for diagnosis of small bowel obstruction and reviewing the current situation of diagnosis and treatment of the disease in terms of pharmacotherapy, gastrointestinal decompression, and surgical intervention.

The relevance of transition zones on computed tomography in the management of small bowel obstruction

BACKGROUND

Frequently, radiologists emphasize radiographic transition zones (RTZs) on computed tomography (CT), which are areas of abrupt change from dilated to collapsed bowel, as pathognomonic for small-bowel obstruction (SBO) diagnosis and location. The relevance of RTZs to patient management remains unknown. The purpose of this study was to determine the surgical predictive value and intraoperative accuracy of RTZ.

METHODS

A retrospective review of 200 patients with SBO who underwent abdominal CT at a single institution from 2002 to 2007 was performed. Statistical analysis was conducted using an unpaired t test, a Chi-square test, and multivariate analysis.

RESULTS

Of the 200 patients with SBO, 150 (75%) had an RTZ. Seventy-five (38%) patients required operative intervention; 58 (39%) patients had RTZ and 17 (34%) patients did not have RTZ (P=NS). The presence of RTZ was not associated with increased probability of operative versus nonoperative management (odds ratio=1.19; 95% confidence interval [0.61-2.32]). The mean time to operative intervention was 3.6 days. Immediate operative intervention (<24 h) was equivalent in patients with versus without RTZ (57% vs 53%; P=NS) as was intervention for failed nonoperative management (43% vs 47%; P=NS). For patients who required operative intervention, RTZ correlated with intraoperative site of obstruction in only 31 (63%) patients.

CONCLUSION

The presence of RTZs does not increase the likelihood of operative intervention or identify patients who will fail nonoperative management. RTZ should, therefore, not be used as a major criterion influencing operative versus nonoperative management decisions in patients with SBO. For patients who required operative intervention, RTZ had a 63% correlation with intra-operative findings, which makes it a useful adjunct to pre-operative planning.

Value of multidetector CT in decision making regarding surgery in patients with small-bowel obstruction due to adhesion

The aim of this study was to evaluate the value of use of multidetector CT (MDCT) to predict the need for subsequent surgery in patients with small-bowel obstruction (SBO) due to adhesion. During a 3-year period, 128 patients with an SBO due to adhesion were enrolled in this prospective study. Initially, all patients were treated conservatively. Surgery was performed in patients who developed signs of strangulation or did not improve, despite a conservative treatment for at least 5 days. Of the 128 patients, 37 patients eventually underwent surgery. Two radiologists interpreted MDCT findings regarded as predictive indicators for subsequent surgery in consensus. The findings included degree of SBO, presence of transition zone, and an abnormal vascular course. These findings were statistically compared between the group operated on and the group not operated on. A higher degree of SBO, an abnormal vascular course, and the presence of transition zone were more frequently seen in the group of patients operated on (p < 0.001). Sensitivities, specificities, positive and negative predictive values, and risks for the use of MDCT to predict the need for surgery were 100%, 46.1%, 43%, 100%, and 1.9 (1.5 < or = 95% confidence interval (CI) < or = 2.2) for a high-grade obstruction; 100%, 23%, 34.5%, 100%, and 1.3 (1.2 < or = 95% CI < or = 1.5) for the presence of a transition zone; and 70.2%, 90.1%, 74.2%, 88.1%, and 7.1 (3.7 < or = 95% CI < or = 13.7) for the presence of an abnormal course of the mesenteric vessels, respectively. The presence of a high degree of SBO and an abnormal vascular course around transition zone are useful indicators on MDCT to predict the need for surgery in patients with an SBO due to adhesion.

Predicting strangulated small bowel obstruction: an old problem revisited

BACKGROUND

Diagnosing intestinal strangulation complicating a small bowel obstruction (SBO) remains a considerable challenge. Despite decades of experience and numerous studies, no clinical indicators have been identified that reliably predict this life-threatening condition. Our goal was to determine which clinical indicators in patients with SBO can be used to independently predict the presence of strangulated intestine.

METHODS

Medical records were reviewed for 192 adult patients operated on for acute SBO over an 11-year period (1996-2006). Seventy-two preoperative clinical, laboratory, and radiologic findings at admission were examined. Data from patients with strangulated intestine were compared to data from patients without bowel compromise. Likelihood ratios were generated for each significant parameter in a multivariate logistic regression analysis.

RESULTS

Forty-four patients had bowel strangulation requiring bowel resection, and 148 had no strangulation. The most significant independent predictor of bowel strangulation was the computed tomography (CT) finding of reduced wall enhancement, with a sensitivity and specificity of 56% and 94% [likelihood ratio (LR) 9.3]. Elevated white blood cell (WBC) count and guarding were moderately predictive (LR 1.7 and 2.8).

CONCLUSION

Regression analysis of multiple preoperative criteria demonstrates that reduced wall enhancement on CT, peritoneal signs, and elevated WBC are the only variables independently predictive of bowel strangulation in patients with SBO.

Early outcomes of surgery for small bowel obstruction: analysis of risk factors

OBJECTIVES

The study aimed to review the etiologies of patients who underwent surgery for small bowel obstruction (SBO) and to evaluate the risk factors affecting the early postoperative outcomes.

MATERIALS AND METHODS

A case series of 430 patients (252 men) with a mean age of 64.5 years, who underwent 437 operations for SBO, were retrospectively reviewed.

RESULTS

Peritoneal adhesions and hernia were the most common causes of SBO, contributing 42.3 and 26.8% of all cases, respectively. Strangulation occurred in 27.7% and caused nonviable bowel in 13.0% of obstructing episodes. Old age (age >/= 70 years), female patient, nonadhesive obstruction, and hernia were the independent significant factors associated with bowel strangulation. The 30-day mortality was 6.5%, and the median postoperative hospital stay was 8 days. Old age, the presence of premorbid pulmonary disease, and malignant obstruction were the independent factors associated with operative mortality. The overall complication rate was 35.5%, and old age was the only significant factor associated with postoperative complications.

CONCLUSIONS

Surgery for SBO is still associated with significant mortality and morbidity. As old age is significantly associated with an increased incidence of strangulation, operative mortality, and complications, this group of patients should be managed with extra cautions to avoid unfavorable outcome of surgery.

Computed tomography diagnosis of ischemia and complete obstruction in small bowel obstruction: a systematic review

This review was designed to describe the diagnostic performance of computed tomography (CT) in assessing bowel ischemia and complete obstruction in small bowel obstruction (SBO). A MEDLINE search (1966-2004) identified 15 studies dealing with the CT diagnosis of ischemia and complete obstruction in SBO. Ischemia was defined by operative findings, and complete obstruction was defined by enteroclysis or operative findings. Aggregated sensitivity, specificity, and positive and negative predictive values (PPV and NPV) were calculated. Eleven of 15 studies reported on the CT diagnosis of ischemia in SBO based on 743 patients. The aggregated performance characteristics of CT for ischemia in SBO were sensitivity of 83% (range, 63-100%), specificity of 92% (range, 61-100%), PPV of 79% (range, 69-100%), and NPV of 93% (range, 33.3-100%). Seven of 15 studies evaluated the CT classification of complete obstruction based on 408 patients. The aggregated performance characteristics of CT for complete obstruction were sensitivity of 92% (range, 81-100%), specificity of 93% (range, 68-100%), PPV of 91% (range, 84-100%), and NPV of 93% (range, 76-100%). This review demonstrates the high sensitivity of CT for ischemia in the setting of SBO and suggests that a CT scan finding of partial SBO is likely to reflect a clinical condition that will resolve without surgical intervention.

Early postoperative small bowel obstruction

BACKGROUND

Early postoperative small bowel obstruction (EPSBO) is a distinct clinical entity that is often difficult to differentiate from postoperative ileus.

METHODS

A literature search was performed for articles dealing with early postoperative small bowel obstruction using Medline and Google.

RESULTS AND CONCLUSION

When bowel function does not return within 5 days after surgery, causes of persistent ileus should be excluded and treated. Most instances of mechanical EPSBO can be treated expectantly for at least 10-14 days with almost no risk of bowel strangulation. Some causes of obstruction (for example herniation at a laparoscopic trocar site) require early reintervention, whereas in other cases (such as radiation enteritis, carcinomatosis) reintervention may be deferred indefinitely. Many episodes of EPSBO resolve without the cause being elucidated.