Reimaging study in the management of blunt abdominal trauma in children: a low income country single center experience

Ethical statement

This study was a cross-sectional retrospective study. This study received retroactive approved by the Ethical Committee for Research at Faculty of Medicine of Monastir (approval number: IORG 0009738 No125/OMB 0990-0279). Patient consent for the use of data records was waived by the ethical committee due to the retrospective nature of the study.

Design and patients

This is a single center retrospective study carried out from January 2010 to December 2021 to examine the records of children with BAT admitted to the Pediatric Surgery Department and intensive care unit (ICU) at Fattouma Bourguiba Hospital Tunisia.

We included all patients younger than 14 years old, hospitalized for BAT associated or not to other concomitant body region injuries and who had undergone successful or unsuccessful non-operative management (NOM). The patients with penetrating traumas (four cases) or useless medical records (nine cases) were excluded.

The demographic characteristics, injury mechanism, physical examination; vital signs, abdominal and general exam, laboratory tests, imaging modality and findings were analyzed. Liver, spleen, kidney, pancreas, and adrenal glands were regarded as SVI. The bowel (duodenal, jejunoileal) and mesentery were defined as hollow viscera injuries (HVI). The urologic injuries included bladder and ureteral lesions. The scoring scale of these lesions was assessed according to the AAST grade. Grades I, II, and III liver, spleen and kidney injuries and grade I and II pancreas injuries were classified as a low-grade, while grade IV and V liver, spleen, and kidney injuries and grade III, IV, and V pancreatic injuries were classified as a high-grade. The hemoperitoneum extent was characterized by the Federle score as large, moderate, or minimal.

Overall, traumatic children were treated according to the protocol as shown in Flowchart I. During hospitalization, the management ensures adherence to the patient’s needs including bed rest, regular clinical assessment of vital signs and abdominal status, hemoglobin measurements, pain management, null-per-os for at least 24 hours, imaging control, and blood transfusion: if hypotension, tachycardia (age-adjusted) or hemoglobin less than 7g/dl. Throughout the monitoring process, both clinical and imaging evolution thus follow-up were recorded.

Definition of groups and statistical analysis

A statistical analysis was realized by comparing two groups. Group one (G1) had no complication on reimaging controls and group two (G2) included patients with complications on reimaging studies (increased hemoperitoneum, occurrence of pseudoaneurysms, pseudocysts, perirenal hemato-urinoma expansion or infection, venous thrombosis, devascularized or hypotrophic organ) needing surgical or radiological intervention or additional tests.

A descriptive statistic was used to summarize patients, injuries grading, clinical and imaging characteristics. The data were summarized as counts and rates for categorical variables or mean for ordinal variables. A subset univariate analysis was done to assess complication rates in relation to the lesion grade of each SVI. Chi-Square tests and Fisher’s exact tests were used to compare results. The relationship between various variables and the complications identified in the reimaging studies was assessed using univariate analysis thus binary logistic regression. The calculations were made for the odds ratio (OR) and 95% confidence interval (CI). A p value of 0.05 or lower was regarded as significant.

Liver injuries

Four patients failed NOM and resuscitation. The reimaging study, performed for tachycardia and hemoglobin drop, revealed enlarged hemoperitoneum in three cases, and devascularized left liver with ongoing bleeding from the left portal vein in one case, required thus operative intervention. On the 15^th day after surgery, one of them experienced a pseudoaneurysm (PA) dependent on the left hepatic artery branch. This patient underwent conservative treatment with imaging control until the PA was completely removed from the circulation around the 24^th day. Angiography/angioembolization (AG/AE) was necessary in a grade III injury case that developed a pseudoaneurysm. Anti-coagulant treatment was prescribed in two cases of portal branch thrombosis; one of them developed cavernoma without portal hypertension. However, complicated reimaging findings were significantly correlated to high grade hepatic injuries (29.4% (5/17) of high-grade vs 5% (2/41) of low-grade, p=0.019).

Spleen injury

NOM was effective in all cases, with 100% of low and high-grade reimaged splenic lesions showing no complications on control, thus, no statistics were computed.

Kidney and urologic injuries

There were two patients with severe reno-vascular lesions due to the dissection of the right renal artery, and the left renal artery and venous thrombosis resulting in a non-enhancement of the right kidney. NOM was decided in both patients given the associated severe liver and spleen injuries. Both patients developed atrophic kidneys, without hypertension during the three years of follow-up. Therefore, the complicated reimaging findings were also significantly correlated to high grade renal injuries 55.5% of high-grade vs no complication in low-grade, p=0.002.

Two cases of extra-peritoneal bladder rupture were successfully treated by urinary drainage via a urethral catheter. The CT-scan with delayed phase imaging carried out one month later revealed no extra-bladder leakage.

Pancreas injury

The patient who initially had a grade IV pancreatic lesion associated with duodenal transection died two days later from severe post-traumatic pancreatitis and multiple organ failure. During the follow-up, 10 children developed pseudocysts. One child with grade IV lesion developed corporeal caudal pancreatic atrophy within one year, but no other long-term complications were observed. There were no significant differences detected among the patients with low and high-grade pancreatic lesions in terms of complication rates 87.5% of high-grade vs 80% of low-grade, p=0.6.

Hollow viscera injury

The patient with intramural hematoma complained of abdominal pain with distended and diffuse abdominal tenderness associated with septicemia four days after admission. The second CT revealed pneumoperitoneum. At exploration, there was a fecal peritonitis owing to two perforations. Reimaging studies conducted eight days following admission revealed the resorption of the mesenteric root hematoma.

Isolated hemoperitoneum

Seven patients (7/20) with an isolated hemoperitoneum required a re-imaging for persistent abdominal pain in three cases, for concomitant vomiting in two cases and for tachycardia associated with decreased hemoglobin (2 g/dl) in two cases. No radiological amendments were observed in all cases, and they were discharged after 48 hours.

Liver

The liver injury is one of the most common life-threatening injuries in children trauma,⁶ and the most severely affected organ in our series. The successful rate of NOM is being expanded by endovascular procedures (AG/AE) in case of an active bleeding (contrast blush).^3,4 However, in stable status, the presence of a contrast blush on the initial CT scan is not an absolute indication for the AG/AE and serial clinical evaluations through physical exams and laboratory testing must be performed to detect a change in clinical status during NOM.⁴ While routine follow-up imaging in children is clearly not indicated and the category of patients who might benefit has not been obviously defined, a small number of patients with grade IV or V liver injury have shown significant complications.^5,7

We performed a follow-up imaging in 98.3% (58/59) of hepatic injury cases, for a clinical indication in 27 cases and routine control in 31 cases. It showed a stabilization or healing signs in 88% of cases and complications in 12%.

We observed that the high rate of complications was statistically correlated with the high-grade hepatic lesion. The rate of post-trauma liver-related complications is greater in our results than that reported in the literature which generally varies from 0% to 7.4%.^8,9

In fact, some authors identify the presence of an active contrast extravasation as an independent predictor for a pseudo aneurysm formation in children, regardless of the injury grade. They suggest a follow-up during NOM of these patients, so as to obtain an early identification and angiographic treatment of pseudoaneurysm.¹⁰ In our study, one patient required AE and one resolved spontaneously.

In addition to the high-grade injury, centrally located liver injuries are significant risk factors for major bile duct injury and complications.^11,12

Given our findings, we suggest that the imaging controls be performed in all symptomatic patients with or without modified laboratory tests, regardless of the severity of the lesion, and systematically in patients with high-grade and central liver lesions on pre-discharge and 2 to 3 weeks post-discharge, and then it will depend on control findings.

Spleen

The splenic injury was the second most injured organ in our series, while it is the most frequent in the pediatric trauma according to the literature.¹³ NOM is based on a close clinical monitoring with the assessments of the hemoglobin and the hematocrit levels every 12–24 h if no complication occurs.¹³

In our series, 34.6% of cases had associated lesions and 14% had high-grade injuries; all patients were successfully treated with NOM and no complications were documented in the reimaged patients. Most studies showed a low rate of complications in pediatric patients with post-traumatic splenic injuries, particularly low-grade ones.⁵ Therefore, follow-up imaging cannot be considered mandatory for low-grade and uncomplicated injuries or asymptomatic patients, but it may be considered in high-grade injuries for the risk of developing life-threatening complications.¹³ In fact, the risks of delayed splenic rupture and posttraumatic pseudocysts seem to be increased within the first one to three weeks^13,14 with an incidence of 0.2 and 5–13%, respectively.^15,16 The 2022 WSES consensus preconizes, imaging follow-up with contrast-enhanced ultrasonography (CEUS) before return to major physical activity in children with AAST grades III–V splenic injuries treated observantly although the repeated imaging in children is rarely needed in the acute phase during NOM.¹⁴ The patients with low- and high-grade injuries didn’t develop any complications. Thus, we propose reimaging before discharge and return to scholar activity.

Kidney and urologic tract

The kidney is affected in 10% of all BAT.¹⁷ The isolated urinary extravasation, in itself, is not an absolute contra-indication to NOM, and the presence of non-viable tissue (devascularized kidney) is not an indication to operative management in the acute setting in the absence of other indications for laparotomy.¹⁸ In our study, the renal trauma involved 17% of patients. Most cases presented low-grade injuries (17/26), and were observantly managed. In fact, the complication rate after blunt renal injury has been estimated at 3-30%.¹⁹ No issues were documented in low-grade cases. A high-grade lesion, observed in 35% of cases, was strongly associated with the high complication rate reported on follow-up imaging in our series. Indeed, low-grade kidney injuries have a very low rate of late complication in pediatric patients; therefore, scheduled imaging follow-up is not indicated.¹⁸ Follow-up imaging in pediatric patients should be limited to moderate (AAST III) and severe (AAST IV-V) injuries. In pediatric patients, US and CEUS should be the first choice in the early and delayed follow-up phases, if cross-sectional imaging is required, magnetic resonance should be preferred.¹⁸ Some authors preconize periodical monitoring of the injury to rule out complications. They recommended time points range from four-24 hours to 48 to 72 hours following the initial scan.^20,21 However, the usefulness of this measure in asymptomatic children has not been satisfactorily proven.²² Some also propose imaging follow-up 3 months following trauma, though there is no unanimous consensus on this.²³ Moreover, periodically examine patients with high-grade injuries should be performed in order to rule out the development of hypertension.²²

Our results concur with the literature data, therefore we propose US/CEUS follow-up imaging for renal high-grade and urologic tract injuries on the third day if the patient is still asymptomatic and at two, six, and 12 weeks after the injury.

Pancreas

Pediatric pancreatic injury is rare, with an incidence of 0.6 to 9.5% of all abdominal injuries,^24,25 which is similar to our results and represents 8.6%.

CT-scan is usually the first-line imaging tool in the assessment of late complications of pancreatic trauma and very useful in driving management.²⁶ However, US or CEUS is used as an alternative to CT for follow up of fluid collections, pseudocysts, and pancreatic disruptions after pancreatic trauma mainly in children or in low-resource settings.²⁶ Furthermore, regular followed up at two, four, eight and 12 weeks to monitor serum amylase, lipase and blood glucose, as well as to perform the abdominal US was also mentioned.²⁷ In fact, in low resource settings, amylase and lipase, in combination with US, can be considered cost-effective tool of patient risk stratification.²⁸ Otherwise, WSES recommend that the necessity for follow-up imaging should be driven by clinical symptoms (i.e., onset of abdominal distention, tenderness, fever, vomiting, jaundice). Endoscopic retrograde cholangiopancreatography (ERCP) is also useful for obtaining an exact diagnosis and determining the status of the main pancreatic duct and location of the pancreatic injury and plan management strategies.²⁹

Hollow viscera

Patients with hollow viscera and mesenteric injuries account for 2–6% of BAT, and more often cause clinical uncertainty,^30,31 because even the hemoperitoneum can lead to an abdominal tenderness. Usually, the pneumoperitoneum detected on CT scan requires an operative management. However, due to the diagnostic complexity and the lack of agreed consensus on clinical management of patients with hollow viscera injury, surgical intervention is often delayed.³²

Our work has some limitations as it is a retrospective study involving information bias. Additionally, the contemporary, and the worldwide recommendations were not followed while treating our patients. Therefore, it is anticipated that prospective studies with updated and adopted guidelines, including management and imaging follow-up, will really be carried out and assessed.