The increased use of seat belts has led to a reduction in fatalities related to road traffic accidents. Proper design and correct usage of seat belts generally prevent vehicle occupants from being violently thrown against the steering wheel, dashboard, or windshield. However, this also raises the risk of intra-abdominal injuries associated with “seat belt syndrome.”¹

Seat belt syndrome typically refers to the combination of seat belt markings on the body, lumbar spine fractures, intra-abdominal injuries, chest wall injuries, and vascular injuries. The seat belt sign is characterized by ecchymosis of the abdomen wall after a car crash. This symptom indicates the presence of interior damage that must not be ignored. It is essential for the early detection of intra-abdominal injuries.² Intra-abdominal injuries can take numerous forms, including mesenteric injuries, adhesion strictures, and perforation, all of which can lead to bowel blockage with a delayed onset of nonspecific symptoms, making a prompt diagnosis challenging.³

We hope that this report will shed light on intra-abdominal injuries following seat belt injury in an initially hemodynamically stable patient, and highlight the importance of the seat belt sign for its early detection.

A 39-year-old male patient, who had neither diabetes nor hypertension, was brought to the outpatient department with a reported history of injuries from a car accident that occurred 12 days earlier. He had received conservative treatment at another hospital before being transferred for further evaluation and management. Since the incident, the patient experienced pain and swelling in his right lower limb. Upon examination, his vital signs were found to be normal, and he was conscious and coherent.

Upon abdominal examination, the patient’s abdomen was soft and distended, with seat belt marks and induration present on the lower abdomen. A trauma screening was performed. Computed tomography (CT) imaging of the right knee joint showed a type V Schatzker fracture of the right tibial plateau. CT scans of the cervical spine, chest, and head were normal. Abdominal and pelvic CT revealed a 2 × 3 cm hematoma in the abdominal wall at the right iliac fossa and fat stranding at the ileocecal junction, with no evidence of obstruction.

The patient underwent right proximal tibial dual plating for the tibial fracture and was referred to a surgeon for an opinion on the hematoma on the abdominal wall. A thorough examination was conducted. Upon inspection of the abdomen, a seat belt mark was noted over the lower abdomen; however, there were no signs of intestinal obstruction. The patient was managed conservatively.

Due to the high likelihood of delayed intestinal obstruction in such circumstances, regular follow-up was recommended, and the patient was discharged after a thorough explanation of the symptoms of intestinal obstruction. Two weeks later, the patient returned to the outpatient department for a follow-up visit, reporting intermittent pain in the lower abdominal wall and no instances of vomiting. Abdominal ultrasonography (USG) revealed no significant abnormalities, and examination indicated that the hematoma was resolving. The abdomen was soft in all other quadrants, and bowel sounds were present. The patient was managed conservatively and advised to continue with follow-up appointments.

Two weeks later, the patient returned, presenting with intermittent severe abdominal pain persisting for four days, accompanied by diarrhea and nausea. There was no history of vomiting or constipation. Abdominal USG revealed a small bowel obstruction. A CT scan of the abdomen with intravenous contrast showed acute small intestinal obstruction with a transition point in the distal ileum, dilated ileal loops with adjacent mesenteric fat stranding, and a possible stricture or inflammatory origin (Fig. 1). Consequently, the patient was diagnosed with acute small bowel obstruction.

Figure 1. Comparison of computed tomography images at a 2-month interval. The yellow circle indicates fat stranding. The red circle indicates stricture of the small bowel with fat stranding. The orange arrow indicates dilated small bowel loops with multiple air/fluid levels.

Considering the obstruction, we obtained written and oral informed consent to proceed with laparoscopic resection and anastomosis.

Under general anesthesia, the patient underwent laparoscopic resection and anastomosis. A four-port approach was employed. A pneumoperitoneum of 15 mmHg was established for the procedure. The small bowel was carefully inspected to exclude any perforation or occlusion. A stricture was identified at two sites in the ileum, creating a loop of small bowel obstruction, located approximately 25 cm from the ileocecal junction and associated with a thickened mesentery. This segment of the ileum was excised using a linear stapler (Fig. 2), and a side-to-side anastomosis was constructed. The resected ileum was removed through the umbilical port. The ports were then closed in layers. The entire surgical process, from the initial incision to skin closure, took approximately 1 hour and 30 minutes. Blood loss was minimal, totaling about 15 mL.

Figure 2. Resected specimen of the small bowel loop stricture.

The postoperative period was uneventful. The excised specimen measured 18 cm in length and included a constricted area of 1 cm. This area appeared grayish-white and firm, with associated mesenteric thickening characterized by tiny gray-white spots. Histologically, the constricted area exhibited mucosal ulceration with granulation tissue and transmural non-caseating granulomas. These granulomas contained foreign body giant cells intermingled with acute inflammatory infiltrates. The patient was discharged two days after surgery.

Following the laparoscopic resection, the patient was observed for one month. Postoperative USG revealed no abnormalities. After undergoing tibial plating and daily leg-strengthening exercises, the patient has since recovered and begun walking.

The clinical presentation of seat belt syndrome often lacks specificity, which can delay diagnosis and treatment. Typical symptoms include abrasions on the chest and abdominal walls, referred to as the “seat belt sign.” The presence of the seat belt sign suggests that intra-abdominal injuries are eight times more likely than when these marks are absent.⁴

Injury to hollow organs typically presents with peritoneal signs, while vascular injuries often result in hypovolemic signs. The primary mechanism of intra-abdominal injury is compression between the seat belt and the spinal column, coupled with intestinal ischemia due to mesenteric tears. Such tears usually occur from a shearing force exerted on the mesentery as the movable intestines maintain the vehicle’s velocity despite the car decelerating. The crushing of the intestines between the vertebrae and the anterior abdominal wall causes a rapid increase in intraluminal pressure. This leads to tangential tears at the fixed points of the bowel and mesentery, and subsequent perforation, which manifests as symptoms of peritonitis. Patients with these injuries typically present with acute symptoms.^1,5,6

However, the presentation of some cases is delayed if an intestinal stricture is present, which is often attributable to ischemia caused by mesenteric damage. This can lead to infarction of the affected segment, which then heals through fibrosis, resulting in a subsequent narrowing of the lumen.³

Hematoma or perforation of the bowel can compromise blood supply and result in constriction. Initially, these cases often present with benign symptoms, but signs of intestinal obstruction may appear several weeks later. Seatbelt injuries, which continue to pose challenges for surgeons, have a better prognosis with early diagnosis. Regular examinations, CT scans, and follow-up appointments are crucial for the timely detection of intestinal injuries in polytrauma patients, especially those exhibiting the seat belt sign.⁷

Initial CT scans may appear normal in many instances, which can lead to a missed early diagnosis. However, regular follow-up scans are advantageous for diagnosing injuries, even in patients who do not present with the seat belt sign, as certain intestinal injuries have been documented in the absence of this sign.⁸

In addition, multi-slice CT enterography and colonoscopy may aid in the diagnosis of intestinal obstruction.⁹ In the present case, the presence of free intraperitoneal fluid on the initial CT scan and the observation of a narrow small intestine on the second imaging examination provided crucial clues for the preoperative diagnosis of delayed intestinal obstruction caused by a seat belt injury.¹⁰

There is no standard treatment for seat belt syndrome; it depends on the affected organ and the patient’s overall condition.² In cases of acute small bowel obstruction with stricture resulting from seat belt syndrome, the preferred treatment is either open or laparoscopic resection followed by anastomosis. Conversely, vascular and parenchymal injuries may be managed conservatively or surgically, based on the injury’s severity.¹¹

In conclusion, Despite an increase in motor vehicle accidents, seat belt use has significantly reduced the number of fatalities. However, injuries can still occur due to improper use of seat belts. For instance, abdominal wall hematoma in the seat belt area necessitates abdominal USG to exclude potential intestinal and mesenteric compression injuries that could lead to acute intestinal obstruction from stricture formation within the first one to two months post-injury.

This case illustrates the potential for a delayed manifestation of small bowel loop stricture resulting from the compression of the bowel loop against the mesentery. Regular follow-up examinations and careful monitoring of the patient’s symptoms are essential for prompt diagnosis and treatment.

Since laparoscopic resection offers a quicker recovery than open surgery, it may serve as a safe and effective alternative for treating intestinal strictures.

None.

The data that support the findings of this study are available from the corresponding author upon reasonable request.

No potential conflict of interest relevant to this article was reported.