Small bowel obstruction (SBO) is a frequently encountered surgical emergency, accounting for approximately 15–20% of all acute abdominal admissions and a substantial proportion of emergency laparotomies worldwide [1,2]. Despite advances in diagnostic imaging and perioperative care, SBO continues to be associated with significant morbidity, prolonged hospital stay, and considerable healthcare burden [3]. Postoperative adhesions remain the leading cause, followed by hernias, malignancies, and inflammatory bowel diseases [4,5].

The clinical management of SBO primarily revolves around distinguishing patients who can be managed conservatively from those who require urgent surgical intervention. While non-operative management is successful in a large proportion of cases, delayed surgery in patients with bowel ischemia, strangulation, or closed-loop obstruction can lead to catastrophic complications, including bowel necrosis, perforation, sepsis, and death [6,7]. Therefore, early and accurate identification of patients at high risk for complications is critical for improving outcomes.

Traditionally, clinical evaluation combined with laboratory parameters has been used to guide decision-making; however, these methods often lack sufficient sensitivity and specificity to reliably predict bowel compromise [8]. In this context, imaging plays a pivotal role, with contrast-enhanced computed tomography (CT) emerging as the gold standard modality for evaluating SBO [9,10]. CT not only confirms the presence, level, and cause of obstruction but also provides valuable information regarding bowel viability and associated complications.

Several CT findings have been described as potential indicators of complicated SBO requiring surgical intervention. These include reduced or absent bowel wall enhancement, suggestive of impaired perfusion; pneumatosis intestinalis and portal venous gas, indicative of advanced ischemia; mesenteric edema and engorgement, reflecting venous congestion; and free intraperitoneal fluid, which may signify inflammatory or ischemic processes [11–13]. Among these, closed-loop obstruction is particularly significant, as it represents a surgical emergency due to its high risk of rapid progression to strangulation [16].

Despite the widespread use of CT, there remains considerable variability in the interpretation and predictive value of these radiological findings across studies. Some features demonstrate high specificity but low sensitivity, while others are frequently present but less predictive when considered in isolation [17–19]. Furthermore, the combined effect of multiple CT findings in predicting surgical necessity has not been consistently quantified.

Given these challenges, a comprehensive synthesis of available evidence is necessary to better define the role of CT in guiding management decisions in SBO. A systematic review and meta-analysis can provide pooled estimates of diagnostic accuracy and help identify the most reliable imaging predictors of surgical intervention.

Therefore, the present study aims to systematically evaluate and quantify CT findings associated with the need for operative management in patients with small bowel obstruction. By identifying the most clinically relevant imaging predictors, this study seeks to enhance early risk stratification, support evidence-based decision-making, and ultimately improve patient outcomes.

Study Design and Reporting Guidelines

This systematic review and meta-analysis was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines [14]. The methodology was predefined to ensure transparency, reproducibility, and minimization of bias.

Search Strategy

A comprehensive literature search was performed across the following electronic databases:

• PubMed/MEDLINE
• Embase
• Scopus
• Cochrane Library

The search included studies published up to December 2025. A combination of Medical Subject Headings (MeSH) terms and free-text keywords was used:

Search terms:

• “small bowel obstruction” OR “intestinal obstruction”
• “computed tomography” OR “CT”
• “predictors” OR “risk factors”
• “surgical intervention” OR “operative management”
• “ischemia” OR “strangulation”
• Boolean operators (AND, OR) were applied to refine the search. Reference lists of relevant articles were also manually screened to identify additional eligible studies.

Eligibility Criteria

Inclusion Criteria

• Studies involving adult patients (≥18 years) with small bowel obstruction
• Studies evaluating CT imaging findings as predictors
• Studies reporting surgical vs conservative management outcomes
• Observational studies (prospective or retrospective cohort, case-control)
• Studies providing sufficient data to calculate odds ratios (ORs)

Exclusion Criteria

• Case reports, case series (<10 patients), editorials, and reviews
• Pediatric-only studies
• Non-English publications
• Studies lacking extractable or relevant outcome data

Study Selection

All identified articles were imported into reference management software, and duplicates were removed. Two independent reviewers screened titles and abstracts for eligibility. Full-text articles were then assessed based on inclusion and exclusion criteria.

Any disagreements were resolved through discussion or consultation with a third reviewer. The study selection process was documented using a PRISMA flow diagram.

standardized data extraction form was used. The following variables were collected:

• Study characteristics: author, year, country, study design
• Patient demographics: sample size, age distribution
• CT findings evaluated (e.g., bowel wall enhancement, pneumatosis, mesenteric edema, free fluid, closed-loop obstruction)
• Outcome measures: need for surgical intervention
• Number of patients in operative vs non-operative groups

Data extraction was performed independently by two reviewers to minimize bias.

Quality Assessment

The methodological quality of included studies was assessed using the Newcastle-Ottawa Scale (NOS) for observational studies [15]. The scale evaluates three domains:

• Selection of study groups
• Comparability of groups
• Outcome assessment

Studies scoring ≥7 were considered high quality, 5–6 moderate quality, and <5 low quality.

Definition of CT Predictors

CT findings were defined based on commonly accepted radiological criteria:

• Reduced bowel wall enhancement: decreased contrast uptake compared to adjacent bowel loops
• Pneumatosis intestinalis: presence of gas within the bowel wall
• Mesenteric edema: increased attenuation or haziness of mesenteric fat
• Free intraperitoneal fluid: fluid without solid organ injury
• Closed-loop obstruction: segment of bowel obstructed at two points forming a loop

These definitions were standardized across studies to ensure consistency in analysis.

Outcome Measure

The primary outcome was the requirement for surgical intervention, defined as operative management (laparotomy or laparoscopy) during the index admission.

Statistical Analysis

Meta-analysis was performed using a random-effects model (DerSimonian–Laird method) to account for inter-study variability.

• Effect size was expressed as odds ratio (OR) with 95% confidence intervals (CI)
• Heterogeneity was assessed using:
• I² statistic (low <25%, moderate 25–50%, high >50%)
• Chi-square test (p < 0.10 considered significant)

Subgroup and sensitivity analyses were performed where applicable.

Publication Bias

Publication bias was assessed using:

• Funnel plot symmetry
• Egger’s regression test

A p-value <0.05 was considered indicative of significant bias.

Software Used

Statistical analyses were performed using:

• Review Manager (RevMan) version 5.4
• Stata version 16.0

Study Selection

The initial database search yielded a total of 1,246 records. After removal of duplicates (n = 312), 934 studies were screened based on titles and abstracts. Of these, 72 articles were assessed for full-text eligibility. Finally, 18 studies met the inclusion criteria and were included in the qualitative and quantitative synthesis.

Figure 1. PRISMA flow diagram illustrating the study selection process. A total of 1,246 records were identified through database searching, of which 934 remained after duplicate removal. Following title and abstract screening, 72 full-text articles were assessed for eligibility. Ultimately, 18 studies were included in the qualitative and quantitative synthesis.

Study Characteristics

The included studies comprised 3,245 patients with small bowel obstruction. The majority were retrospective cohort studies, with a smaller number of prospective analyses. The proportion of patients requiring surgical intervention ranged from 34% to 48% across studies.

Table 1: Characteristics of Included Studies

Overall, study quality was moderate to high, with most studies scoring ≥6 on the Newcastle-Ottawa Scale.

Quantitative Synthesis of CT Findings

Meta-analysis demonstrated that several CT findings were significantly associated with the need for surgical intervention (Table 2).

Table 2: Pooled Analysis of CT Predictors of Surgery

Narrative Analysis of Findings

Among the evaluated CT parameters, pneumatosis intestinalis demonstrated the strongest association with surgical intervention (OR 6.21), indicating advanced bowel ischemia. Similarly, closed-loop obstruction showed a high predictive value (OR 5.76), reflecting its well-established association with strangulation.

Reduced bowel wall enhancement, a marker of impaired perfusion, was also significantly associated with operative management (OR 4.12). This finding was consistently reported across multiple studies and showed moderate heterogeneity (I² = 42%).

Mesenteric edema and free intraperitoneal fluid were moderately predictive but widely prevalent among patients undergoing surgery. Although these findings are less specific, their presence in combination with other CT features increased predictive accuracy.

3.5 Combined CT Findings

Several studies reported that the presence of two or more CT predictors significantly increased the likelihood of surgical intervention. Patients exhibiting multiple radiological signs had a 2–3 fold higher probability of requiring operative management compared to those with isolated findings.

3.6 Heterogeneity and Sensitivity Analysis

Moderate heterogeneity was observed across studies, particularly for free intraperitoneal fluid (I² = 51%). Sensitivity analysis excluding lower-quality studies did not significantly alter pooled estimates, indicating robustness of results.

3.7 Publication Bias

Funnel plot analysis demonstrated relative symmetry, suggesting a low risk of publication bias. Egger’s test was not statistically significant (p > 0.05), further supporting the reliability of findings.

3.8 Summary of Key Findings

• Strong predictors: pneumatosis intestinalis, closed-loop obstruction
• Moderate predictors: reduced bowel wall enhancement, mesenteric edema
• Supportive predictors: free intraperitoneal fluid
• Combined CT findings significantly improve diagnostic accuracy

Figure 2. Combined forest plots demonstrating the association between computed tomography findings and the need for surgical intervention in small bowel obstruction. Panels illustrate reduced bowel wall enhancement, closed-loop obstruction, pneumatosis intestinalis, and mesenteric edema with free intraperitoneal fluid. Squares represent individual study estimates, horizontal lines denote 95% confidence intervals, and diamonds indicate pooled odds ratios using a random-effects model.

Figure 3. Funnel plot assessing publication bias among included studies. The vertical line represents the pooled effect size. Diagonal lines indicate pseudo 95% confidence intervals. The regression line corresponds to Egger’s test for small-study effects. The symmetrical distribution of studies suggests minimal publication bias.

This systematic review and meta-analysis comprehensively evaluated the role of computed tomography (CT) in predicting the need for surgical intervention in patients with small bowel obstruction (SBO). The findings demonstrate that specific CT features-particularly those indicative of bowel ischemia and strangulation-are strongly associated with operative management. Among these, pneumatosis intestinalis, closed-loop obstruction, and reduced bowel wall enhancement emerged as the most robust predictors.

Interpretation of Key Findings

In the present analysis, pneumatosis intestinalis showed the highest predictive value (OR 6.21), underscoring its significance as a marker of advanced bowel ischemia. This finding is consistent with earlier radiological studies, which have identified pneumatosis as a late but highly specific indicator of transmural bowel necrosis [17,25]. Although its sensitivity is limited, its presence should prompt urgent surgical consideration due to the high risk of irreversible bowel injury.

Similarly, closed-loop obstruction demonstrated a strong association with surgical intervention (OR 5.76). This aligns with the classical understanding that closed-loop configurations predispose to rapid vascular compromise and strangulation [16,24]. Prior studies have emphasized that delayed recognition of this entity significantly increases morbidity, reinforcing the need for early identification on CT imaging.

Reduced bowel wall enhancement, reflecting compromised perfusion, also showed a significant association (OR 4.12). This finding is widely regarded as one of the earliest radiological indicators of ischemia and has been consistently reported in multiple studies [18,26]. Its detection is particularly valuable in guiding early operative decision-making before irreversible damage occurs.

Moderately predictive findings such as mesenteric edema (OR 3.45) and free intraperitoneal fluid (OR 2.89) were also significantly associated with surgical outcomes. These features likely represent secondary changes related to venous congestion and inflammatory processes [19,27]. Although less specific, their presence in conjunction with other CT findings enhances diagnostic confidence.

Comparison with Existing Literature

The present findings are consistent with prior systematic reviews and observational studies that have highlighted the importance of CT in stratifying SBO severity. Millet et al. demonstrated that CT signs of ischemia, particularly decreased enhancement and mesenteric fluid, were strongly predictive of the need for surgery [11,28]. Similarly, Zielinski et al. reported that combining radiological findings with clinical parameters significantly improved prediction accuracy [21,32].

Ceresoli et al. emphasized the role of CT as the cornerstone of SBO evaluation, particularly in identifying patients requiring early surgical intervention [13]. Our meta-analysis extends these observations by quantitatively synthesizing evidence across multiple studies and confirming that ischemic markers carry the highest predictive weight.

Furthermore, recent radiological literature suggests that multidetector CT (MDCT) has improved the detection of subtle ischemic changes, thereby enhancing diagnostic accuracy [31]. This advancement may explain the relatively strong associations observed in more recent studies included in this analysis.

Importance of Combined CT Findings

A key observation from this study is that no single CT finding should be interpreted in isolation. Several included studies demonstrated that the presence of multiple CT predictors significantly increases the likelihood of surgical intervention [28–30]. This supports a cumulative risk model, where the coexistence of ischemic and obstructive features markedly elevates clinical concern.

For example, a patient presenting with both reduced bowel wall enhancement and mesenteric edema is at substantially higher risk than one with either finding alone. This reinforces the concept of integrating multiple imaging features into a composite assessment rather than relying on individual signs.

Clinical Implications

The findings of this study have important implications for clinical practice:

• Early risk stratification: CT can reliably identify high-risk patients requiring urgent surgery
• Reduction in delayed intervention: Recognition of ischemic signs may prevent complications such as necrosis and perforation
• Guidance for conservative management: Absence of high-risk CT findings may support non-operative treatment
• Standardization of reporting: Incorporating key CT predictors into structured reporting systems can improve decision-making

Integration of CT findings with clinical and laboratory parameters may further enhance predictive accuracy and should be encouraged in future clinical protocols.

Strengths of the Study

• Inclusion of a large pooled population (n = 3,245)
• Use of standardized meta-analytic methods
• Comprehensive evaluation of multiple CT predictors
• Consistent findings across heterogeneous study designs

Limitations

Despite its strengths, this study has certain limitations:

• Predominance of retrospective studies, introducing potential bias
• Variability in CT protocols and interpretation across studies
• Lack of standardized definitions for some imaging findings
• Limited availability of patient-level data for subgroup analysis

Additionally, heterogeneity in reporting surgical indications across studies may have influenced pooled estimates.

Future Directions

Future research should focus on:

• Prospective multicenter studies with standardized imaging protocols
• Development of validated CT-based scoring systems
• Integration of radiological, clinical, and biochemical markers
• Application of artificial intelligence and radiomics for improved prediction

Such approaches may further refine decision-making and optimize patient outcomes.

In summary, this meta-analysis confirms that CT findings-particularly those indicating bowel ischemia-are strong predictors of surgical intervention in SBO. Closed-loop obstruction, pneumatosis intestinalis, and reduced bowel wall enhancement are the most reliable indicators.

A combined assessment of multiple CT features provides the highest predictive accuracy and should be incorporated into routine clinical evaluation to guide timely and appropriate management.

This systematic review and meta-analysis demonstrates that computed tomography (CT) is a highly reliable tool for predicting the need for surgical intervention in patients with small bowel obstruction. Among the evaluated imaging features, closed-loop obstruction, pneumatosis intestinalis, and reduced bowel wall enhancement emerged as the most significant predictors, reflecting underlying bowel ischemia and impending strangulation.

Importantly, the findings highlight that no single CT parameter is sufficient in isolation; rather, a combined assessment of multiple radiological features provides superior predictive accuracy and should form the basis of clinical decision-making. Early identification of high-risk CT findings can facilitate timely surgical intervention, thereby reducing complications such as bowel necrosis, perforation, sepsis, and mortality.

From a clinical standpoint, integrating CT findings with clinical and laboratory parameters into a structured risk stratification approach may significantly improve patient outcomes and optimize resource utilization.

Future research should focus on developing standardized CT-based scoring systems and validating them in large prospective cohorts, as well as exploring the role of artificial intelligence and radiomics in enhancing diagnostic precision.

In conclusion, CT imaging is indispensable in the modern management of small bowel obstruction, serving not only as a diagnostic modality but also as a critical tool for guiding therapeutic decisions and improving patient prognosis.

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