Intestinal injuries: diagnosis and surgical tactics

Intestinal injuries occur with blunt and penetrating abdominal trauma and include damage to the small and large intestines, mesentery, and serosa, including ruptures of the wall and contamination of the abdominal cavity. According to modern reviews, intestinal injuries are found in approximately 1% of victims with blunt trauma, and up to 17% or more with penetrating trauma, often in combination with other intra-abdominal injuries. This is a "rare but dangerous" category, where a delay in diagnosis increases the risk of peritonitis and sepsis. [1]

The initial assessment always follows the principles of enhanced advanced trauma support (Primary Survey, Stabilization of Vital Signs), followed by targeted diagnostics: enhanced fast-acting ultrasound in trauma (E-FAST), physical examination, laboratory tests, and contrast-enhanced CT scan of the abdomen. In a vigorous patient without signs of shock, contrast-enhanced CT scan is the imaging modality of choice for detecting "hard" and "soft" signs of injury. [2]

Treatment tactics depend on the hemodynamics, mechanism, and severity. In unstable patients, immediate laparotomy is indicated using damage control principles (control of the source of contamination and bleeding, temporary abdominal closure). In stable patients, precise damage verification and organ-preserving treatment are preferred, including primary suturing or resection with anastomosis for colorectal trauma, rather than routine stoma. [3]

In recent years, the criteria for computed tomography have been refined (“hard” signs - extraluminal gas, contrast, wall defect; “soft” - wall thickening, free fluid without parenchymal damage, etc.), the American Association of Trauma Surgeons Intestinal and Mesenteric Injury Severity Scale (AAST OIS, 2020) has been updated, and the WSES recommendations offer practical algorithms from diagnosis to the choice of reconstruction method. [4]

Codes according to the International Classification of Diseases, 10th and 11th revisions

In the International Classification of Diseases, Tenth Revision (ICD-10-CM), small bowel injuries are coded in block S36, "Injury of intra-abdominal organs," with further details (e.g., S36.4 - small bowel injury, S36.5 - colon injury, S36.6 - rectal injury). The mechanism (Y-codes) and associated injuries are also indicated. Complication codes (peritonitis, sepsis), if present, are used for accompanying documentation. [5]

The International Classification of Diseases, Eleventh Revision (ICD-11) uses the NC3 section "Trauma of the Peritoneum and Intra-Abdominal Organs," where intestinal injuries are coded by location and type, with the ability to post-coordinate features (mechanism - blunt/stab, open/closed, severity, presence of perforation and contamination). Post-coordination support allows for a single entry to reflect "anatomy + mechanism + complication." [6]

Table 1. Coding examples

System	Code	Example of wording
ICD-10-CM	S36.4	Small bowel injury (specify closed/open)
ICD-10-CM	S36.5	Colon trauma
ICD-11	NC3… (+ modifiers)	Small/large bowel trauma with post-coordination mechanism and complications
Additional codes	T81. , A41.	Postoperative peritonitis, sepsis (if present)

Epidemiology

Overall, bowel injuries occur in approximately 1% of patients with blunt abdominal trauma and 17% with penetrating injuries, but the incidence varies by institution and type of injury. Penetrating injuries to the colon and rectum are often accompanied by concomitant pelvic and genitourinary trauma. [7]

A significant proportion of victims are not diagnosed immediately: some patients present without typical symptoms, and "mild" CT scan findings require follow-up and re-evaluation. A delay in diagnosis of more than 8-12 hours increases the risk of peritonitis, sepsis, and suture failure. [8]

According to registries, the predominant injury patterns in blunt trauma include ruptures of the small intestine and mesentery with "bucket-handle" ruptures of the mesenteric vessels, while penetrating trauma involves stab wounds of the colon and rectum. A combination with splenitis, liver, pancreatic, and vascular trauma is common. [9]

Prognosis improves with early referral to a trauma center and adherence to standardized diagnostic and treatment protocols. Centralized teams demonstrate lower stoma rates, better reconstruction quality, and lower mortality. [10]

Table 2. Epidemiological landmarks

Indicator	Meaning
Share in blunt trauma	≈ 1% of victims
Share in penetrating trauma	up to 17%
Common scenarios	Small bowel/mesenteric lacerations (blunt), colon/rectal injuries (penetrating)
Key factor in outcome	Time to diagnosis and source control

Reasons

Primary mechanisms: blunt kinetic trauma (road collision, seat belt compression, crush injury, fall) and penetrating wounds (stab, gunshot). Blunt trauma is typically characterized by mesenteric ruptures with segmental ischemia ("bucket-handle"), wall contusions/tears, and avulsions at attachment sites. [11]

In penetrating trauma, damage depends on the type of projectile, its energy, angle, and multiple trajectories; gunshot wounds are characterized by more extensive contamination and tissue devitalization. Multiple intestinal loops and adjacent organs are often affected. [12]

Iatrogenic injuries occur during endoscopy, laparoscopy and open procedures; early recognition and immediate repair of the defect are essential for the prevention of peritonitis. [13]

A separate block is combined injuries in polytrauma with mesenteric ruptures and microperforations: clinical symptoms can develop gradually, which requires vigilance and monitoring protocols. [14]

Risk factors

High kinetic energy impacts (high velocities, falling from a vehicle), a seat belt sign on the anterior abdominal wall, rib/pelvic fractures, pneumoperitoneum on plain radiographs all increase the likelihood of intestinal injury.[15]

Alcohol intoxication, decreased consciousness, and associated injuries complicate clinical assessment and increase the risk of diagnostic delay. In children and elderly patients, symptoms may be subtle. [16]

In penetrating trauma, additional factors include multi-channel wound tracts, high-energy projectiles, delayed delivery to the hospital, and concomitant damage to the mesenteric vessels. [17]

The presence of peritonitis, shock, massive contamination and a “dirty” wound are factors that increase the risk of anastomotic failure and indicate the need for step-by-step reconstruction or delayed anastomosis after “damage control”. [18]

Pathogenesis

Injuries include contusion, partial rupture, complete rupture of the wall, mesenteric avulsion with ischemia and necrosis, and perforations with fecal contamination. In blunt trauma, the mechanism is shear forces and the crush effect at the sites of intestinal fixation; in penetrating trauma, it is direct tissue destruction and cavitation. [19]

Mesenteric "bucket-handle" ruptures lead to ischemia without immediate perforation, which explains late peritonitis despite initially "inconclusive" imaging. On CT, they are revealed by mesenteric hematomas, vascular ruptures, and asymmetric perfusion of the intestinal segment. [20]

Microperforations and wall contusions may not produce early "hard" signs; what is important here are "soft" signs (free fluid without parenchymal damage, wall thickening, pneumatosis) and re-evaluation after 6-12 hours. [21]

The pathophysiology of peritonitis and sepsis in contaminated environments is related to bacterial translocation and the inflammatory cascade; therefore, early source control and antibiotic prophylaxis are key to reducing complications.[22]

Symptoms

Classic symptoms include abdominal pain and tension, peritoneal irritation, nausea, vomiting, and gas/stool retention. However, in the early stages and in patients with concomitant injuries, the picture may be unclear. [23]

The skin "seat belt sign," abrasions, and bruises on the abdomen are important clues. Fever, tachycardia, leukocytosis, and metabolic acidosis with increasing pain are warning signs of late diagnosis. [24]

In penetrating trauma, external wounds in the abdomen/pelvis, blood from the rectum, gas in the wound channel, and fecal contamination are present. Extraperitoneal rectal injuries can be relatively insidious and require targeted investigation. [25]

In children, there is often a refusal to eat, crying during palpation, and vomiting; in the elderly, there is poor symptomatology due to anticoagulants and polymorbidity, which dictates a low threshold for computed tomography. [26]

Table 3. Clinical clues

Sign	What to suspect	The next step
Seat belt sign, pain	Intestinal/mesenteric contusion/rupture	Contrast-enhanced computed tomography
Bleeding from the rectum due to trauma	Colon/rectal trauma	Examination, rectoscopy/CT, to the operating room as indicated
Fever, tachycardia after 6-12 hours	Late perforation/ischemia	Repeat CT scan/diagnostic laparoscopy
Pneumoperitoneum, extraluminal contrast	Reliable perforation	Emergency laparotomy/laparoscopy

Classification, forms and stages

The AAST OIS scale (2020 update) for small/large bowel and mesentery is used in practice: from I (contusion/hematoma) to V (devascularization of a large segment, destruction). This scale helps standardize messages, prognosis, and decision-making. [27]

A distinction is made between blunt and penetrating injuries; the latter are intra-abdominal and extraperitoneal (this is crucial for the rectum). Mesenteric injuries (vascular ruptures, ischemia) are considered a separate category, often requiring resection of the non-viable segment. [28]

Wound contamination—"clean-contaminated," "contaminated," "dirty"—determines the choice of reconstruction tactics and the need for delayed anastomosis or stoma. Shock, massive contamination, and coagulopathy are arguments in favor of a multistage approach. [29]

For the duodenum and rectum, there are additional nuances (retroperitoneality, access), so their algorithms are highlighted separately in the EAST/WSES guidelines. [30]

Table 4. Simplified: AAST OIS Bowel Score (Meaning Levels)

Degree	The nature of the damage	Note
I-II	Contusion/tear without perforation	Conservative tactics are possible for stable ones
III	Rupture < 50% of circumference	Seam/primary repair
IV	Rupture > 50% of circumference or multiple	Resection ± anastomosis
V	Devascularization/total detachment	Resection, often in stages

Complications and consequences

The main risks are peritonitis, sepsis, anastomotic leakage, intra-abdominal abscesses, and fistulas. The risk of complications increases with diagnostic delays, shock, massive contamination, and coagulopathy. [31]

Colorectal anastomotic leakage and pelvic abscesses are common in colorectal trauma. Current data show that, for "minor" injuries and controlled contamination, primary suturing or resection with anastomosis are as safe as stoma and, in select individuals, offer better quality of life. [32]

Mesenteric ischemia may manifest later despite a “negative” initial CT scan; therefore, follow-up and repeat studies are critical.[33]

After damage control, open abdomen problems may occur: fluid/protein loss, wound infections, ventral hernias - a management plan and early definitive closure upon stabilization are required. [34]

When to see a doctor

Immediately - for any abdominal injury with increasing pain, muscle tension, fever, vomiting, tarry stools, blood from the rectum, or signs of shock (paleness, cold sweat, rapid pulse, drop in blood pressure). This is an indication to call an ambulance. [35]

After an accident or a fall with a “belt sign” on the stomach, even if you feel well, it is advisable to go to a trauma center: some injuries appear after hours. [36]

After a stab/gunshot wound to the abdomen, emergency treatment is required. Self-irrigation or attempts at treatment are unacceptable. [37]

After endoscopy or laparoscopy, if increasing pain, fever, or bloating occurs, consult a doctor immediately to rule out iatrogenic perforation. [38]

Diagnostics

The first step is stabilization using the advanced trauma support algorithm: respiratory and circulatory control, anti-shock measures, and timely blood transfusion. Simultaneously, an extended ultrasound examination in trauma (E-FAST) and a physical examination are performed. [39]

The second step is contrast-enhanced computed tomography of the abdominal cavity in hemodynamically stable patients. "Hard" signs of intestinal injury include extraluminal gas, contrast leakage, an obvious wall defect, and active contrast enhancement in the mesentery; "soft" signs include wall thickening, mesenteric infiltration, and free fluid without parenchymal damage. The presence of "hard" signs is an indication for surgery. [40]

The third step is dynamic observation for "soft" signs: a repeat examination, laboratory markers (leukocytosis, lactate), a control CT scan after 6-12 hours, or diagnostic laparoscopy if doubt persists. If clinical deterioration occurs, do not delay surgery. [41]

The fourth step is for penetrating trauma: low threshold for diagnostic laparoscopy/laparotomy if perforation is suspected, mandatory assessment of the rectum (examination, rectoscopy) for lower bowel injuries; for extraperitoneal rectal wounds, the issue of diversion, drainage, and antibiotics is decided according to protocols. [42]

Table 5. Computed tomographic features

Group	Examples	Tactics
"Tough"	Extraluminal gas/contrast, wall defect, active bleeding	Urgent surgery
"Soft"	Free fluid without parenchymal injury, wall thickening, mesenteric infiltration	Observation + re-evaluation/laparoscopy
Mesentery	Hematoma, vascular rupture, asymmetric segment perfusion	High risk of ischemia - low threshold for resection

Differential diagnosis

In blunt trauma, intestinal injuries are masked by contusions of the anterior abdominal wall, parenchymal trauma to the liver/spleen with moderate hemoperitoneum, and retroperitoneal hematomas. These are differentiated by fluid distribution, the presence of gas outside the lumen, and mesenteric infiltration. [43]

Primary peritonitis/inflammation is differentiated from traumatic peritonitis based on history, mechanism, and CT scan data. In patients with peptic ulcer disease, gastric/duodenal perforation unrelated to trauma is possible. [44]

In penetrating wounds, intrathoracic sources of pain and shock (pressure pneumothorax) and vascular accidents are excluded; trauma center protocols and damage control priorities are decisive here. [45]

Extraperitoneal rectal injuries should be distinguished from isolated ruptures of the anal canal - rectal examination and endoscopy are strategically important. [46]

Table 6. Red flags for bowel injury

Situation	Possible problem	What to do
Free gas outside the lumen	Perforation of the intestine/hollow organ	To the operating room
Free fluid without parenchymal injury	Suspected intestinal injury	Dynamics/laparoscopy
"Belt sign" + pain	Intestinal/mesenteric contusion/rupture	Contrast-enhanced computed tomography
Mesenteric hematoma, segment hypoperfusion	Ischemia, risk of late perforation	Low threshold for resection

Treatment

Initial management is determined by hemodynamics. An unstable patient with signs of intra-abdominal catastrophic failure requires direct laparotomy, following damage control principles: rapid elimination of the source of contamination and bleeding, temporary closure, and transfer to intensive care to correct hypothermia, acidosis, and coagulopathy. Definitive reconstruction is performed after stabilization. [47]

In stable patients with "hard" CT findings, early surgery is recommended. For small small bowel ruptures, primary transverse suturing is possible; for defects or multiple lesions, segmental resection with primary anastomosis is recommended with satisfactory perfusion and no significant contamination. Routine stoma is not required. [48]

In colonic injuries, current data support primary repair or resection with anastomosis in selected patients (without shock, without massive contamination, with good blood supply and no significant edema). Diversion (stoma) is indicated for devastating injuries, severe shock, "dirty" wounds, and questionable tissue viability. This reduces unnecessary stomas and reoperations. [49]

Extraperitoneal rectal wounds: Options include diversion, drainage, and sometimes direct wound debridement (distal rectal washout—used to a limited extent). The choice depends on the defect, contamination, and associated injuries; current guidelines are updated, but the general trend is toward selective diversion rather than "mandatory" diversion. [50]

Mesenteric "bucket-handle" ruptures require careful evaluation of bowel viability. If perfusion is questionable, it is better to resect and restore continuity (or leave a stoma if the overall situation is unfavorable) than to risk late failure. Intraoperative fluorescein angiography with indocyanine may be helpful if available. [51]

The role of laparoscopy: in stable patients, diagnostic and therapeutic laparoscopy is acceptable with appropriate expertise (suturing of limited defects, irrigation, drainage). However, if multiple injuries or massive contamination are suspected, laparotomy is preferred. [52]

Antibiotics: Early antibacterial prophylaxis against aerobes and anaerobes (e.g., beta-lactam/beta-lactamase inhibitor or 2nd-3rd generation cephalosporin + metronidazole) is mandatory in intestinal trauma; duration depends on the degree of contamination and source control (usually 24-48 hours with adequate debridement, longer in peritonitis/sepsis). [53]

Postoperative management: early enteral support for peristalsis, thromboembolism prevention, pain control, dynamic monitoring of lactate, temperature, and leukocytes. In the case of "damage control," a plan is to return to the operating room in 24-48 hours for final reconstruction and closure of the abdominal cavity. [54]

The choice between primary anastomosis and stoma is a decision made by a team of specialists, taking into account the "rule of four": physiology (shock/vasopressors), degree of contamination, tissue quality/perfusion, and technical feasibility of drainage and monitoring. If in doubt, a delayed anastomosis may be performed in the second stage after stabilization. [55]

Rehabilitation and management of complications: alertness for leakage (pain, tachycardia, flatulence, fever, leukocytosis), timely CT scan with contrast, and drainage of abscesses. After stoma, a plan for programmed closure in the absence of inflammation and satisfactory nutritional support. [56]

Table 7. Colorectal trauma: what to choose

Situation	Preferably	Avoid
Minor damage, no shock, controlled contamination	Primary suture/resection with anastomosis	Routine stoma "for safety"
Severe shock, coagulopathy, massive contamination	Damage control, sabotage	Long reconstructions in the first run
Extraperitoneal rectum	Selective diversion + drainage	"Mandatory" sabotage for everyone

Prevention

Primary prevention includes road safety (belts, child restraints), occupational injury prevention, and violence reduction. Proper seating and seat belt use reduce the risk of severe abdominal injuries, although the "belt sign" remains an indicator of potential injury. [57]

Secondary prevention - early detection algorithms: low threshold for CT scanning in patients with "risk" features, standardized protocols for re-evaluation of "soft" findings, training of emergency medical teams to recognize dangerous symptoms. [58]

Antibiotic prophylaxis and strict source control prevent infectious complications. In the intensive care unit, prevention of thrombosis, stress ulcers, and early mobilization are recommended. [59]

Routing to a trauma center with abdominal trauma expertise reduces the rate of diagnostic delays and unnecessary stomas, improves survival and quality of life. [60]

Table 8. Checklist for preventing complications

Risk	Measure
Late diagnosis	Re-evaluation 6-12 hours for "soft" signs
Infectious complications	Early antibiotic therapy, adequate sanitation
Insolvency	Perfusion assessment, informed choice of anastomosis/stoma
Complications of open abdomen	Early final closure upon stabilization

Forecast

Outcome depends on the time to diagnosis and source control, the severity of the injury, the presence of shock, and coagulopathy. Early surgery for "hard" signs and structured follow-up for "soft" findings reduce mortality and the incidence of peritonitis. [61]

In colorectal trauma, modern strategies prioritizing primary repair/anastomosis in selected patients can reduce the frequency of stomas without increasing complications. Multistage reconstructions are appropriate for severe physiology and "dirty" wounds. [62]

Mesenteric lesions with ischemia are a “silent killer”: with vigilance and early resection of unfavorable segments, the prognosis is significantly better. [63]

Overall, referral to a center with a team of trauma-abdominal surgeons, radiologists, and anesthesiologists increases the chances of a favorable outcome and reduces disability. [64]

Table 9. What influences the outcome the most?

Factor	Influence
Delay in diagnosis > 8-12 hours	Increase in peritonitis/sepsis/mortality
Shock, coagulopathy, massive contamination	Risk of insolvency, indications for damage control
Choice of reconstruction	In selected patients, benefit from primary repair
The center's experience	Lower rate of stomas and complications

FAQ

Is a stoma always performed for colonic injury?
No. In selected patients without shock or massive contamination, primary suturing or resection with anastomosis is safe and preferable; a stoma is needed selectively. [65]

If the CT scan is "questionable," can we simply observe?
Yes, but according to protocol: follow-up examinations, lab tests, a control CT scan in 6-12 hours, or diagnostic laparoscopy if there are any doubts. If clinical deterioration occurs, immediate surgery is necessary. [66]

What CT findings require urgent surgery?
Extraluminal gas, contrast leakage, obvious bowel wall defect, and active bleeding are "hard" signs of perforation/rupture. [67]

Does everyone with bowel injury need antibiotics?
Yes, if bowel injury is confirmed or highly likely, early antibacterial prophylaxis against aerobes and anaerobes is indicated; duration depends on source control. [68]