CT scan-detected pneumoperitoneum: an unreliable predictor of intra-abdominal injury in blunt trauma

Abdominal computed tomography scoring systems and experienced radiologists in the radiological diagnosis of small bowel and mesenteric injury

PURPOSE

Blunt bowel and/or mesenteric injury requiring surgery presents a diagnostic challenge. Although computed tomography (CT) imaging is standard following blunt trauma, findings can be nonspecific. Most studies have focused on the diagnostic value of CT findings in identifying significant bowel and/or mesenteric injury (sBMI). Some studies have described scoring systems to assist with diagnosis. Little attention, has been given to radiologist interpretation of CT scans. This study compared the discriminative ability of scoring systems (BIPS and RAPTOR) with radiologist interpretation in identifying sBMI.

METHODS

We conducted a retrospective chart review of trauma patients with suspected sBMI. CT images were reviewed in a blinded fashion to calculate BIPS and RAPTOR scores. Sensitivity and specificity were compared between BIPS, RAPTOR, and the admission CT report with respect to identifying sBMI.

RESULTS

One hundred sixty-two patients were identified, 72 (44%) underwent laparotomy and 43 (26.5%) had sBMI. Sensitivity and specificity were: BIPS 49% and 87%, AUC 0.75 (0.67-0.81), P < 0.001; RAPTOR 46% and 82%, AUC 0.72 (0.64-0.79), P < 0.001; radiologist impression 81% and 71%, AUC 0.82(0.75-0.87), P < 0.001. The discriminative ability of the radiologist impression was higher than RAPTOR (P = 0.04) but not BIPS (P = 0.13). There was not a difference between RAPTOR vs. BIPS (P = 0.55).

CONCLUSION

Radiologist interpretation of the admission CT scan was discriminative of sBMI. Although surgical vigilance, including evaluation of the CT images and patient, remains fundamental to early diagnosis, the radiologist's impression of the CT scan can be used in clinical practice to simplify the approach to patients with abdominal trauma.

Index CT-Based Scoring Systems in Operative Blunt Bowel and Mesenteric Injury Identification

INTRODUCTION

Determining the need for surgical management of blunt bowel and mesenteric injury (BBMI) remains a clinical challenge. The Faget score and Bowel Injury Prediction Score (BIPS) have been suggested to address this issue. Their efficacy in determining the need for surgery was examined.

METHODS

A retrospective review of all adult blunt trauma patients hospitalized at a level 1 trauma center between January 2009 and August 2019 who had small bowel, colon, and/or mesenteric injury was conducted. We further analyzed those who underwent preoperative computed tomography (CT) scanning at our institution. Final index CT reports were retrospectively reviewed to calculate the Faget and BIPS CT scores. All images were also independently reviewed by an attending radiologist to determine the BIPS CT score.

RESULTS

During the study period, 14,897 blunt trauma patients were hospitalized, of which 91 had BBMI. Of these, 62 met inclusion criteria. Among patients previously identified as having BBMI in the registry, the retrospectively applied Faget score had a sensitivity of 39.1%, specificity of 81.2%, positive predictive value (PPV) of 85.7%, and negative predictive value (NPV) of 31.7% in identifying patients with operative BBMI. The retrospectively applied BIPS score had a sensitivity of 47.8%, specificity of 87.5%, PPV of 91.7%, and NPV of 36.8% in this cohort. When CT images were reviewed by an attending radiologist using the BIPS criteria, sensitivity was 56.5%, specificity 93.7%, PPV 96.3%, and NPV 42.8%.

CONCLUSIONS

Existing BBMI scoring systems had limited sensitivity but excellent PPV in predicting the need for operative intervention for BBMI. Attending radiologist review of CT images using the BIPS scoring system demonstrated improved accuracy as opposed to retrospective application of the BIPS score to radiology reports.

Application of Computed Tomography in the Identification of Hollow Viscus Injuries in Blunt Trauma Patients

Purpose: Despite advances in diagnostic and imaging technologies, the diagnosis of traumatic hollow viscus injury (HVI) remains a great challenge in clinical practice. This study aimed to determine the accuracy of computed tomography (CT) in the diagnosis of HVI in emergent blunt trauma patients.Methods: The study was conducted on patients with abdominal trauma who were admitted to our center, regional emergency center, Kyung Hee University Medical Center, between January 2008 and December 2018. The clinical data of patients with abdominal trauma who underwent CT and abdominal surgery within 24 hours of hospitalization were analyzed to determine the diagnostic capacity of CT.Results: In total, 156 patients were included in the study. There were 88 cases of blunt trauma. Among these patients, 27 were diagnosed with HVI using CT, and 38 patients were diagnosed with HVI in the operating room. The median injury severity score for these patients was 10.0, the revised trauma score was 7.841, and the trauma injury severity score was 0.96. The sensitivity and specificity of CT in predicting HVI in these patients were 65.8%, and 96.0%, respectively. The positive and negative predictive values were 92.6%, and 78.7%, respectively.Conclusion: In urgent situations, CT findings alone are insufficient for diagnosing HVI. Further research on the HVI diagnostic capacity of CT is required.

Delayed diagnosed trauma in severely injured patients despite guidelines-oriented emergency room treatment: there is still a risk

Purpose

Emergency trauma room treatment follows established algorithms such as ATLS®. Nevertheless, there are injuries that are not immediately recognized here. The aim of this study was to evaluate the residual risk for manifesting life-threatening injuries despite strict adherence to trauma room guidelines, which is different to missed injuries that describe recognizable injuries.

Methods

In a retrospective study, we included 2694 consecutive patients admitted to the emergency trauma room of one single level I trauma center between 2016 and 2019. In accordance with the trauma room algorithm, primary and secondary survey, trauma whole-body CT scan, eFAST, and tertiary survey were performed. Patients who needed emergency surgery during their hospital stay for additional injury found after guidelines-oriented emergency trauma room treatment were analyzed.

Results

In seven patients (0.26%; mean age 50.4 years, range 18–90; mean ISS 39.7, range 34–50), a life-threatening injury occurred in the further course: one epidural bleeding (13 h after tertiary survey) and six abdominal hollow organ injuries (range 5.5 h–4 days after tertiary survey). Two patients (0.07% overall) with abdominal injury died. The “number needed to fail” was 385 (95%–CI 0.0010–0.0053).

Conclusion

Our study reveals a remaining risk for delayed diagnosis of potentially lethal injuries despite accurate emergency trauma room algorithms. In other words, there were missed injuries that could have been identified using this algorithm but were missed due to other reasons. Continuous clinical and instrument-based examinations should, therefore, not be neglected after completion of the tertiary survey.

Level of evidence

Level II: Development of diagnostic criteria on the basis of consecutive patients (with universally applied reference “gold” standard).

Traumatic hollow viscus and mesenteric injury: role of CT and potential diagnostic-therapeutic algorithm

Despite its rarity, traumatic hollow viscus and mesenteric injury (HVMI) have high mortality and complication rates. There is no consensus regarding its best management. Our aim is to evaluate contrast enhanced CT (ceCT) in the screening of HVMI and its capability to assess the need for surgery. All trauma patients admitted to an urban Level 1 trauma center between 2010 and 2018 were retrospectively evaluated. Patients with ceCT scan prior to laparotomy were included. Patients requiring surgical repair of HVMI and a ceCT scan consistent with HVMI were considered true positives. Six ceCT scan criteria for HVMI were used; at least one criterion was considered positive for HVMI. Sensitivity (Sn), specificity (Sp), predictive values (PV), likelihood ratios (LR) and accuracy (Ac) of ceCT of single ceCT criteria and of the association of ceCT criteria were calculated using intraoperative findings as gold standard. Therapeutic time (TT), death probability (DP), and observed mortality (OM) were described. 114 of 4369 patients were selected for ceCT accuracy analysis; 47 were considered true positives. Sn of ceCT for HVMI was 97.9%, Sp 63.6%, PPV 66.2%, NPV 97.6%, + LR 2.69, −LR 0.03, Ac 78%; no single criterion stood out. The association of four or more criteria improved ceCT Sp to 98.5%, PPV to 95.6%, + LR to 30.5. Median TT was 2 h (IQR: 1–3 h). OM was 7.8%—not significantly higher than overall OM. CeCT in trauma has become a reliable screening test for HVMI and a valid exam to select HVMI patients for surgical exploration.

‘FAST positive’ reversal & pneumoperitoneum: A novel sign of traumatic bladder rupture

Urinary bladder injuries are uncommon, accounting for just 1.6% of all abdominal trauma. The most common presenting symptoms are hematuria, abdominal pain and inability to void. Ascites is the most typical manifestation on CT. We hereby report a case of a 24-year-old male victim of a road traffic injury with an unusual presentation of pneumoperitoneum and “reversal” of FAST positive status as the presenting signs of bladder injury. Prior awareness of urinary bladder injury as the etiology of pneumoperitoneum can possibly decrease morbidity with consideration of minimal access surgery for management. Compared to pneumoperitoneum, “FAST reversal” in catheterized patients is quite peculiar and sufficiently specific per se to warrant a cystogram or thorough intraoperative bladder evaluation.

Diagnostic options for blunt abdominal trauma

PURPOSE

Physical examination, laboratory tests, ultrasound, conventional radiography, multislice computed tomography (MSCT), and diagnostic laparoscopy are used for diagnosing blunt abdominal trauma. In this article, we investigate and evaluate the usefulness and limitations of various diagnostic modalities on the basis of a comprehensive review of the literature.

METHODS

We searched commonly used databases in order to obtain information about the aforementioned diagnostic modalities. Relevant articles were included in the literature review. On the basis of the results of our comprehensive analysis of the literature and a current case, we offer a diagnostic algorithm.

RESULTS

A total of 86 studies were included in the review. Ecchymosis of the abdominal wall (seat belt sign) is a clinical sign that has a high predictive value. Laboratory values such as those for haematocrit, haemoglobin, base excess or deficit, and international normalised ratio (INR) are prognostic parameters that are useful in guiding therapy. Extended focused assessment with sonography for trauma (eFAST) has become a well established component of the trauma room algorithm but is of limited usefulness in the diagnosis of blunt abdominal trauma. Compared with all other diagnostic modalities, MSCT has the highest sensitivity and specificity. Diagnostic laparoscopy is an invasive technique that may also serve as a therapeutic tool and is particularly suited for haemodynamically stable patients with suspected hollow viscus injuries.

CONCLUSIONS

MSCT is the gold standard diagnostic modality for blunt abdominal trauma because of its high sensitivity and specificity in detecting relevant intra-abdominal injuries. In many cases, however, clinical, laboratory and imaging findings must be interpreted jointly for an adequate evaluation of a patient's injuries and for treatment planning since these data supplement and complement one another. Patients with blunt abdominal trauma should be admitted for clinical observation over a minimum period of 24 h since there is no investigation that can reliably rule out intra-abdominal injuries.

Free abdominal gas on computed tomography in the emergency department: aetiologies and association between amount of free gas and mortality

INTRODUCTION

Free abdominal gas is an important finding with major clinical implications. However, data on the aetiologies and prognosis of patients with free gas are scarce. Our primary aim was to describe the sources of free abdominal gas on emergency department (ED) computed tomography (CT). The secondary aim was to evaluate the association between the amount of free gas and all-cause mortality.

METHODS

All patients who underwent CT in the ED between February 2012 and February 2019 with free abdominal gas were included in the study. A scoring system was used to assess the amount of free gas: small - gas bubbles; medium - any gas pocket ≤2cm in diameter; large - any gas pocket >2cm. Data were collected from laboratory and clinical assessment regarding the source of free gas and all-cause mortality.

RESULTS

A total of 372 patients had free abdominal gas. Colonic diverticulitis was the most common aetiology among those with a small or medium amount of free gas (81/250 [32.4%] and 12/71 [16.9%] respectively). For patients with a large amount of gas, peptic disease was the most common aetiology (11/51 [21.6%]). Three-quarters of the patients (280/372, 75.2%) had the source of free gas identified during ED admission. Ninety-day mortality rates were 7.2%, 9.9% and 21.6% for patients with small, medium and large amounts of gas respectively (p=0.007).

CONCLUSIONS

Colonic diverticulitis was the most common source of free abdominal gas and peptic disease was the most common cause of a large amount of free gas. Mortality rates correlated with the amount of gas and were significantly higher in patients with a large amount.

Imaging of blunt bowel and mesenteric injuries: Current status

Blunt abdominal trauma often presents a diagnostic challenge. Clinical examination demonstrates low reliability in detecting abdominal injury (16 %) when there is a history of head injury or loss of consciousness. This can prove detrimental, as delays in the diagnosis of traumatic bowel injury of 8 h or less can result in increased morbidity and mortality, as well as prolonged hospitalization. Although hemodynamically unstable patients will require an urgent laparotomy following clinical assessment, MDCT is the modality of choice for comprehensive imaging of blunt abdominal trauma in hemodynamically stable patients. Despite the use of MDCT, blunt injury to the bowel and mesentery, which accounts for up to 5% of injuries in cases of trauma, may be difficult to detect. The use of a constellation of direct and indirect signs on MDCT can help make the diagnosis and guide clinical management. Direct signs on MDCT, such as bowel wall discontinuity, and extraluminal gas may assist in the diagnosis of traumatic bowel injury. However, these signs are not sensitive. Therefore, the astute radiologist may have to rely on indirect signs of injury, such as free fluid, bowel wall thickening, and abnormal bowel wall enhancement to make the diagnosis. This review will focus on MDCT imaging findings of bowel and mesenteric injuries secondary to blunt abdominal trauma.

Ability of specific and nonspecific signs of multidetector computed tomography (MDCT) in the diagnosis of blunt surgically important bowel and mesenteric injuries

PURPOSE

To determine the accuracy of MDCT in the evaluation of blunt surgically relevant bowel and/or mesenteric injuries (BMIs) using single specific CT signs together with specific pairs of nonspecific signs.

METHODS

Fifty-four patients examined with MDCT were divided into two groups: a 'surgical' group of 20 patients-which underwent surgery for blunt BMIs-and a control group of 34 'nonsurgical' trauma patients. Two radiologists with different experience performed a double-blind retrospective evaluation of the images, classifying the patients in the two groups by using only single specific signs; then, the images were reviewed in consensus with a third radiologist and sensitivity and specificity were calculated. Subsequently, the frequency of every single sign and of every possible combination of nonspecific signs in the two groups was registered, to find combinations present only in the surgical group; sensitivity and specificity were calculated by using even those specific combinations.

RESULTS

At the first consensual evaluation, sensitivity and specificity were 75 and 100%, respectively. Two combinations of nonspecific signs (focal wall thickening + extraluminal air; focal wall thickening + seat belt sign) were found only in surgical patients that did not present any single specific sign: Sensitivity calculated adding those two combinations was 95%, without a decrease in specificity.

CONCLUSIONS

MDCT is an accurate technique in the evaluation of blunt surgically relevant BMIs. The single specific CT signs were sufficient for the diagnosis in only 75% of the cases; adding the two specific combinations allowed an increase in sensitivity of 20%.

Benign Posttraumatic Pseudopneumoperitoneum

OBJECTIVE

The objective of our study was to retrospectively determine the anatomic distribution of chest wall ectopic gas resembling pneumoperitoneum (i.e., pseudopneumoperitoneum) and its relationship with trauma mechanisms and clinical outcomes using CT.

MATERIALS AND METHODS

Investigators from two separate trauma referral centers screened 492 chest, abdomen, and pelvis CT examinations of patients who had sustained any form of trauma between 2010 and 2015. After excluding 186 patients with recognized causes of ectopic gas, 306 patients (211 men and 95 women; mean age, 44.5 years; range, 6-95 years) remained for analysis by two radiology residents in center 1 and a radiology resident in center 2. Positive cases were reviewed by all investigators, including an experienced fellowship-trained abdominal radiologist. The anatomic location of the pseudopneumoperitoneum, injury severity score, trauma velocity (high speed vs low or unknown speed), trauma mechanism, clinical findings on follow-up, and exploratory laparotomy data were collected for patients with pseudopneumoperitoneum. Two hundred consecutive nontrauma CT examinations from 2015 were selected as control cases by a resident in center 1. The t test and chi-square test were used for determining associations.

RESULTS

Pseudopneumoperitoneum was identified in 5.2% of patients, occurring bilaterally adjacent to the lower six costochondral junctions, and was significantly more common with high-velocity trauma than with low-velocity trauma (p = 0.010). None of the patients with pseudopneumoperitoneum had evidence of perforated hollow viscus at surgery (n = 2) or on clinical follow-up (n = 14). No patients had unnecessary surgery due to pseudopneumoperitoneum.

CONCLUSION

Pseudopneumoperitoneum is a posttraumatic phenomenon centered near the lower six costochondral junctions. Recognizing these findings may help prevent unnecessary laparotomy in the trauma setting.

Surgical Management of Abdominal Trauma: Hollow Viscus Injury

Hollow viscus injury is common with penetrating trauma to the torso and infrequent with a blunt traumatic mechanism of injury. The diagnosis in hemodynamically unstable patients is often made in the operating room. In hemodynamically stable patients, the diagnosis can be difficult due to additional injuries. Although computed tomography remains the diagnostic tool of choice in hemodynamically stable patients, it has lower reported sensitivity and specificity with hollow viscus injury. However, even short delays in diagnosis increase morbidity and mortality significantly. Operative management of stomach, duodenal, small bowel, and colon injuries is reviewed.

Early diagnosis of hollow viscus injury using intestinal fatty acid-binding protein in blunt trauma patients

A delay in diagnosing hollow viscus injury (HVI) causes an increase in mortality and morbidity. HVI remains a challenge to diagnose, and there is no specific diagnostic biomarker for HVI. We evaluated the utility of intestinal fatty acid-binding protein (I-FABP) in diagnosing HVI in blunt trauma patients. Within a 5-year period, 93 consecutive patients with clinically suspected HVI at our trauma center were prospectively enrolled. The diagnostic performance of I-FABP for HVI was compared with that of other various parameters (physical, laboratory, and radiographic findings). HVI was diagnosed in 13 patients (14%), and non-HVI was diagnosed in 80 patients (86%). The level of I-FABP was significantly higher in patients with HVI than in those with non-HVI (P = 0.014; area under the curve, 0.71). The sensitivity, specificity, positive predictive value, and negative predictive value were 76.9%, 70.0%, 29.4%, and 94.9%, respectively (P = 0.003). However, all other biomarkers were not significantly different between the groups. Presence of extraluminal air, bowel wall thickening on computed tomography (CT), and peritonitis signs were significantly higher in patients with HVI (P < 0.05). Of 49 patients (52.7%) who had a negative I-FABP and negative peritonitis signs, none developed HVI (sensitivity, 100%; negative predictive value, 100%). This is the first study that demonstrated the diagnostic value of a biomarker for HVI. I-FABP has a higher negative predictive value compared to traditional diagnostic tests. Although the accuracy of I-FABP alone was insufficient, the combination of I-FABP and other findings can enhance diagnostic ability.

Hollow viscus injury due to blunt trauma: A review

Blunt abdominal trauma results in injury to the bowel and mesenteries in 3-5% of cases. The injuries are polymorphic including hematoma, seromuscular tear, perforation, and ischemia. They preferentially involve the small bowel and may result in bleeding and/or peritonitis. An urgent laparotomy is necessary if there is evidence of active bleeding or peritonitis at the initial examination, but these situations are uncommon. The main diagnostic challenge is to promptly and correctly identify lesions that require surgical repair. Diagnostic delay exceeding eight hours before surgical repair is associated with increased morbidity and probably with mortality. Because of this risk, the traditional therapeutic approach has been to operate on all patients with suspected bowel or mesenteric injury. However, this approach leads to a high rate of non-therapeutic laparotomy. A new approach of non-operative management (NOM) may be applicable to hemodynamically stable patients with no signs of perforation or peritonitis, and is being increasingly employed. This attitude has been described in several recent studies, and can be applied to nearly 40% of patients. However, there is no consensual agreement on which criteria or combination of clinical and radiological signs can insure the safety of NOM. When NOM is decided upon at the outset, very close monitoring is mandatory with repeated clinical examinations and interval computerized tomography (CT). Larger multicenter studies are needed to better define the selection criteria and modalities for NOM.

Usefulness of free intraperitoneal air detected by CT scan in diagnosing bowel perforation in blunt trauma: experience from a community-based hospital

INTRODUCTION

Computed tomography (CT) scan has increasingly become the diagnostic modality of choice for the evaluation of patients with blunt abdominal trauma. CT scan is highly sensitive in the detection of small amounts of free intraperitoneal air (FIA). We aimed to evaluate the usefulness of FIA detected by CT scan in diagnosing bowel perforation in blunt trauma patients.

PATIENTS AND METHODS

All abdominal CT scans of blunt trauma patients who were treated at Al Rahba Hospital during the period from October 2010 till December 2013 were retrospectively reviewed. The results of abdominal CT scan were compared with the clinical follow up and operative findings to evaluate the sensitivity, specificity, predictive values, and usefulness index of CT-detected FIA in diagnosing bowel perforation.

RESULTS

Abdominal CT scans were performed for 419 trauma patients. 21 (5%) patients were found to have FIA, two of them were true positive (10%), six (29%) needed mechanical ventilation, and eleven (52%) had a pneumothorax. 15/21 (71%) patients had multiple FIA pockets; the median (range) was 3 (2-10) air pockets. Two patients with multiple air pockets of 10mm-thick cuts or more had small bowel perforation. Six (29%) patients had a single air pocket of less than 10mm and none had bowel perforation. 398 patients had negative CT scan for FIA; two of them were false negative. CT-detected FIA scan had a sensitivity of 50% (95% CI: 6.8%-93.2%), specificity of 95.4% (95% CI: 92.9%-97.2%.), a positive predictive value of 9.5% (95% CI: 1.2%-30.4%) and a negative predictive value of 99.5% (95% CI: 98.2%-99.9%) for detecting bowel perforation. The usefulness index for abdominal CT scan FIA for detecting bowel perforation was 0.23 (not useful).

CONCLUSIONS

Our study which stemmed from a community-based hospital showed that free intraperitoneal air found on abdominal CT scan of blunt trauma patients was an unreliable radiological finding for bowel perforation. The decision for laparotomy should be based on combined clinical and radiological findings. Conservative management with active observation may avoid unnecessary laparotomy.

Pneumoperitoneum in a patient with pneumothorax and blunt neck trauma

INTRODUCTION

Blunt trauma as a cause of pneumoperitoneum is less frequent and its occurrence without a ruptured viscus is rarely seen.

PRESENTATION OF CASE

We report a case of blunt neck trauma in which a motorcycle rider hit a fixed object causing severe laryngotracheal injury. The patient developed pneumothorax bilaterally and had pneumoperitoneum despite no injury to the internal viscus. Bilateral chest tube drainage and abdominal exploratory laparotomy was performed.

CONCLUSION

Free air in the abdomen after blunt traumatic neck injury is very rare. If pneumoperitoneum is suspected in the presence of pneumothorax, exploratory laparotomy should be performed to rule out intraabdominal injury. As, there is no consensus for this plan yet, further prospective studies are warrant. Conservative management for pneumoperitoneum in the absence of viscus perforation is still a safe option in carefully selected cases.

Isolated abdominal trauma: diagnosis and clinical management considerations

PURPOSE OF REVIEW

The scope of the present study is to review the topics of initial assessment, diagnosis and clinical management of an isolated abdominal trauma.

RECENT FINDINGS

Progress in the management of trauma patients increasing survival includes a multidisciplinary approach involving multiple specialties at presentation. If immediate surgical intervention is needed, 'damage control' is the best option; if not, it has been proven that conservative management is superior to operative, in terms of survival for the majority of intraabdominal injury. 'Open abdomen' should be performed in major abdominal traumas when indicated. Early enteral feeding is beneficial, even in the presence of 'open abdomen'.

SUMMARY

Abdominal trauma is a complex injury; the multidisciplinary approach has made nonoperative management feasible and effective. When surgical intervention is needed, it should be performed in an orderly fashion, within the context of the overall management.