Intestinal obstruction is a common cause of acute abdomen and accounts for a major share of emergency surgical admissions and procedures.¹ The pathophysiology involves interruption of luminal passage with proximal bowel dilatation, fluid sequestration, electrolyte derangement, bacterial translocation, and—when strangulation occurs—ischemia and necrosis. Delayed recognition of bowel compromise increases risk of perforation, sepsis, multi-organ dysfunction, and death. Therefore, management requires rapid resuscitation, accurate diagnosis, etiology identification, and timely decision-making between conservative and operative pathways.² Mechanical obstruction is broadly categorized into small bowel obstruction (SBO) and large bowel obstruction (LBO). The etiologic spectrum varies by geography and surgical burden. In many modern series, postoperative adhesions dominate SBO, whereas colorectal malignancy is a leading cause of LBO.³,⁴ Hernias remain important, particularly in settings with limited access to elective hernia repair, and are associated with higher resection rates and worse outcomes.⁵ In endemic regions, abdominal tuberculosis and inflammatory strictures may contribute substantially. Clinical diagnosis is supported by imaging. Plain radiographs may identify dilated loops and air–fluid levels but are less accurate for defining transition point or ischemia. Computed tomography (CT) is now the preferred modality for most patients because it improves diagnostic accuracy, clarifies etiology, identifies a transition point, and detects complications such as closed-loop obstruction and ischemia.⁶,⁷ CT-based identification of bowel compromise has direct implications for urgency of surgery.⁸ Management has shifted toward structured non-operative protocols for selected adhesive SBO. Evidence-based recommendations support initial conservative management (nil per os, nasogastric decompression when indicated, IV fluids/electrolyte correction, and close monitoring) in patients without peritonitis, strangulation, or perforation.² Use of water-soluble contrast agents may assist diagnosis and sometimes shorten hospital stay, although evidence for reducing operative rates is mixed.⁹,¹⁰ For LBO due to left-sided malignancy, endoscopic stenting as a bridge to surgery is an established option in selected patients and may reduce short-term morbidity compared with emergency surgery, while long-term oncologic outcomes require careful consideration.¹¹,¹² Colonic volvulus management emphasizes endoscopic decompression (when appropriate) and prevention of recurrence with definitive surgery in fit patients.¹³ Despite advances, outcomes remain influenced by delayed presentation, comorbidities, dehydration, sepsis, and bowel ischemia. Protocol-driven pathways combining early CT risk stratification, time-bound conservative trials, and prompt surgery for deterioration may reduce resection, complications, and mortality. This study evaluates current etiologies, management patterns, and outcomes of IO in a tertiary-care setting.

Study design and setting Prospective observational study conducted in a tertiary-care teaching hospital from January 2023 to June 2023. Ethical approval was obtained from the institutional committee, and informed consent was taken from participants (or legally authorized representatives in emergencies). Participants All consecutive eligible adult patients presenting to emergency surgery services with suspected mechanical intestinal obstruction were screened. Inclusion criteria 1. Age ≥18 years. 2. Clinical features suggestive of mechanical obstruction: colicky abdominal pain, vomiting, abdominal distension, constipation/obstipation. 3. Radiologic confirmation of obstruction (X-ray/USG/CT), with CT preferred where available. 4. Patients managed either conservatively or operatively under the surgical unit. Exclusion criteria 1. Paralytic ileus (postoperative ileus, electrolyte-induced ileus) without mechanical transition point. 2. Acute mesenteric ischemia without mechanical obstruction. 3. Pregnancy. 4. Age <18 years. 5. Patients refusing consent or transferred out before definitive evaluation. Clinical evaluation and protocol All patients underwent standardized assessment: vitals, hydration status, abdominal examination for peritonitis, digital rectal examination, and laboratory tests (CBC, renal function, electrolytes, lactate where available). Resuscitation included IV crystalloids, correction of electrolyte disturbances, analgesia, antiemetics, and nasogastric decompression when vomiting/aspiration risk was present. Imaging strategy • CT abdomen/pelvis with IV contrast was used unless contraindicated. • CT findings recorded: transition point, closed-loop features, bowel wall thickening, mesenteric edema, reduced enhancement, pneumatosis, free air/fluid. Management definitions • Non-operative management (NOM): NPO, NG decompression as needed, IV fluids, serial exams, and repeat labs/imaging. A “time-bound” trial (typically 24–72 h) was used for uncomplicated ASBO.² • Operative management: Early surgery for suspected strangulation/peritonitis/perforation, or failure of NOM, or for etiologies requiring definitive treatment (e.g., obstructed hernia, malignancy with complete LBO). Procedures included adhesiolysis, hernia repair ± resection, resection–anastomosis, stoma creation, and volvulus procedures. Outcomes Primary outcomes: etiology distribution, need for surgery, bowel resection rate, complications, length of stay, and in-hospital mortality. Secondary outcomes: predictors of bowel resection and mortality. Statistical analysis Categorical variables presented as n (%); continuous variables as mean±SD or median (IQR). Logistic regression assessed predictors (delayed presentation, CT ischemia, leukocytosis, lactate elevation, SBO vs LBO, comorbidity index). Significance set at p<0.05. Note: The results below are provided in a publication-ready template with internally consistent sample data (n=180). Replace the numbers with your hospital dataset if you want the final manuscript to exactly match your study.

Table 1. Baseline characteristics (n=180) Variable Value Age, mean ± SD (years) 52.6 ± 16.8 Male sex 108 (60.0) Rural residence 98 (54.4) Prior abdominal surgery 92 (51.1) Comorbidities (any) 86 (47.8) Diabetes mellitus 38 (21.1) Hypertension 44 (24.4) CKD 9 (5.0) Presentation >48 hours from symptom onset 62 (34.4) Interpretation: IO predominantly affected middle-aged adults with male preponderance. A history of prior surgery was common, supporting adhesions as a major etiology. One-third presented late (>48 h), a key modifiable risk factor linked to ischemia and resection in many series.² Table 2. Site and etiology of obstruction Etiology SBO (n=112) LBO (n=68) Total (n=180) Adhesions 74 (66.1) 6 (8.8) 80 (44.4) Hernia (obstructed/strangulated) 26 (23.2) 7 (10.3) 33 (18.3) Malignancy 4 (3.6) 26 (38.2) 30 (16.7) Volvulus 0 (0.0) 18 (26.5) 18 (10.0) Intestinal tuberculosis/stricture 6 (5.4) 6 (8.8) 12 (6.7) Others (bezoar, intussusception, foreign body) 2 (1.8) 5 (7.4) 7 (3.9) Interpretation: Adhesions were the leading cause overall and especially for SBO, consistent with contemporary evidence and guidelines.²,³ Malignancy and volvulus dominated LBO, aligning with practice patterns where colorectal cancer is a major cause and sigmoid volvulus remains important.¹¹,¹³ Table 3. Clinical features and imaging findings Parameter n (%) Abdominal pain 168 (93.3) Vomiting 132 (73.3) Distension 146 (81.1) Obstipation 118 (65.6) Fever 28 (15.6) Peritonitis on exam 22 (12.2) CT performed 154 (85.6) Clear transition point on CT 131/154 (85.1) CT signs suggestive of ischemia* 29/154 (18.8) *Reduced enhancement, mesenteric edema, pneumatosis, closed-loop with free fluid. Interpretation: Classic symptom triad was common. High CT utilization enabled etiologic identification and ischemia detection—important because CT has strong diagnostic performance for SBO and complications.⁶,⁷ Table 4. Management profile and operative procedures Management n (%) Initial non-operative management attempted 96 (53.3) Successful NOM (no surgery) 63/96 (65.6) Failed NOM → surgery 33/96 (34.4) Primary early surgery 84 (46.7) Total operated 117 (65.0) Laparoscopic approach (attempted) 18/117 (15.4) Converted to open 6/18 (33.3) Bowel resection required 38/180 (21.1) Stoma created 22/180 (12.2) Interpretation: Over half underwent a monitored conservative trial, with ~two-thirds success—consistent with guideline-supported NOM for uncomplicated ASBO.² Water-soluble contrast can support decision-making, though its effect on operative rate is debated.⁹,¹⁰ Laparoscopy was selectively used; literature notes benefits in selected patients but emphasizes careful case selection due to injury risk.¹⁴ Table 5. Post-treatment complications (in operated patients, n=117) Complication n (%) Surgical site infection 14 (12.0) Pneumonia/atelectasis 9 (7.7) Prolonged ileus (>4 days) 11 (9.4) Anastomotic leak 3 (2.6) Sepsis 6 (5.1) Re-operation 4 (3.4) Any complication 29 (24.8) Interpretation: Infection and ileus were the most frequent complications. Respiratory complications are notable in elderly and hernia-related SBO cohorts, emphasizing perioperative optimization and early mobilization.⁵ Table 6. Outcomes and predictors of bowel resection (multivariable model) Predictor Adjusted OR (95% CI) p-value Presentation >48 h 2.6 (1.2–5.8) 0.01 CT signs of ischemia 5.1 (2.1–12.4) <0.001 Peritonitis 3.4 (1.1–10.2) 0.03 Hernia etiology 2.2 (1.0–4.9) 0.04 Age ≥60 years 1.6 (0.8–3.4) 0.18 Overall outcomes (n=180): median length of stay 6 days (IQR 4–9); ICU admission 14 (7.8%); in-hospital mortality 8 (4.4%). Interpretation: Late presentation and CT ischemia were the strongest predictors of resection, supporting CT-based risk stratification and early surgery when compromise is suspected.⁸

This study highlights adhesions as the predominant etiology of intestinal obstruction, especially SBO, consistent with modern evidence that postoperative adhesions account for the majority of SBO in many healthcare systems.³ The high proportion of prior abdominal surgery in our cohort supports this mechanism and reinforces the importance of adhesion prevention strategies and rational operative decision-making. The Bologna guidelines emphasize CT assessment, identification of bowel compromise, and a structured non-operative trial for uncomplicated ASBO.² Our observed success rate of conservative management (~66% among those selected for NOM) aligns with contemporary practice where carefully monitored NOM is often effective, while early surgery is reserved for peritonitis, strangulation, perforation, or non-resolution. CT was used in the majority of patients and frequently identified a transition point, aiding etiologic classification and urgency decisions. This approach is supported by systematic review evidence demonstrating CT’s strong accuracy for diagnosing SBO, ischemia, and predicting need for surgery.⁷ Importantly, CT signs suggestive of ischemia were an independent predictor of bowel resection in our model, consistent with radiology literature associating reduced enhancement, mesenteric edema, pneumatosis, and closed-loop features with strangulation risk.⁸ Together, these findings validate a pathway of “resuscitate → CT risk stratify → time-bound NOM if uncomplicated → early surgery if compromised.” The role of water-soluble contrast (WSCM) remains nuanced. Several protocols use WSCM to assist prognostication and expedite decisions; however, meta-analytic evidence suggests it may shorten hospital stay but does not reliably reduce operation rates or mortality.⁹,¹⁰ Therefore, its greatest value may be as a decision-support tool within an observation window rather than a definitive therapeutic intervention. For large bowel obstruction, malignancy and volvulus were prominent etiologies. In malignant left-sided LBO, bridge-to-surgery stenting is increasingly utilized in carefully selected patients and settings. High-quality synthesis suggests better short-term surgical outcomes (e.g., higher primary anastomosis rates, reduced blood loss and ICU stay) with comparable long-term survival in many analyses, though oncologic concerns persist and decision-making must be individualized.¹² Contemporary endoscopy guidelines provide structured recommendations for stenting indications and contraindications.¹¹ For volvulus, guideline-based management favors endoscopic decompression when bowel is viable, followed by definitive surgery in suitable candidates to prevent recurrence—consistent with colonic volvulus practice guidance.¹³ Hernia-related obstruction constituted a substantial fraction and was associated with increased odds of bowel resection—mirroring audit data demonstrating worse outcomes in hernia-related SBO cohorts, especially in older patients.⁵ This supports health-system interventions that expand elective hernia repair access and improve early referral for obstructed hernia symptoms. Overall, our results emphasize that outcomes in intestinal obstruction are strongly influenced by modifiable factors—particularly delayed presentation and delayed recognition of ischemia. A standardized institutional protocol integrating early imaging and time-defined decision points is likely to reduce bowel loss, morbidity, and mortality.

Intestinal obstruction remains a high-impact surgical emergency. Adhesions are the leading etiology of SBO, while malignancy and volvulus predominate in LBO. Best outcomes are achieved through: (1) prompt resuscitation, (2) early CT-based risk stratification, (3) monitored, time-bound non-operative management in uncomplicated ASBO, and (4) early surgery for bowel compromise or failed conservative care. Late presentation and CT signs of ischemia are key predictors of bowel resection and adverse outcomes.

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