Sternal fracture in the emergency department: diagnostic value of multidetector CT with sagittal and coronal reconstruction images

Diagnostic Value of Ultrasound for Sternal Fractures in Patients with Trauma Experiencing Anterior Chest Wall Pain

Background: Ultrasound is an attractive modality for the confirmation of sternal fractures in patients with trauma because of its easy, quick, and accurate nature, as well as its increased availability for focused assessment with sonography for trauma at the bedside. We aimed to confirm the diagnostic value of ultrasonography for sternal fractures in patients with trauma, anterior chest wall pain, and tenderness. Methods: This retrospective observational study included patients visiting a single regional trauma center from March 2022 to February 2023, diagnosed with sternal fractures via chest CT and bone scans, who underwent sternal ultrasound. Results: Twenty-six patients were divided into two groups: those with sternal fractures diagnosed with an initial chest CT scan (n = 19) and those without fractures (n = 7). Using ultrasound, 23 patients (88.5%) were diagnosed with sternal fractures. In the initial CT scan (+) group, all 19 patients (100%) were diagnosed using ultrasound. In the initial CT scan (-) group, four (57.1%) of the seven patients were diagnosed using ultrasound. In the initial CT scan (+) group, 14 (73.7%) of the 19 patients underwent bone scans and all 14/14 (100%) were diagnosed with sternal fractures. In the initial CT scan (-) group, seven (100%) patients underwent bone scans, and all were diagnosed with sternal fractures. Conclusions: Ultrasound is useful for the diagnosis of sternal fractures, with sensitivity of 88.5%. Therefore, in patients with blunt trauma experiencing anterior chest wall pain and tenderness, sternal ultrasonography might be helpful in diagnosing sternal fractures as an adjunct to chest CT and bone scans.

A Man With Chest Pain After An Assault - A Case Report

This case report highlights an uncommon sequelae of chest wall trauma that should be evaluated for patients presenting with similar history and symptoms. A 60-year-old man presented to the emergency department (ED) with swelling, fever, and chest wall pain two days after an assault with blunt chest wall trauma. On exam, there was a suspected chest wall abscess, verified on computed tomography (CT) with associated displaced midsternal fracture. This patient was admitted for abscess incision and drainage. While uncommon, chest wall abscess formation is an important condition that should be considered as a differential diagnosis in any patient presenting with chest wall pain post blunt trauma. With few reported similar presentations in the literature, this case is an important addition in a likely underreported phenomenon that requires prompt evaluation and treatment.

Topics

Blunt chest trauma, chest wall abscess, sternal fracture complication.

Minor Trauma, Major Discovery: The Ultrasound Identification of a Sternal Fracture Missed by Computed Tomography in an Older Patient Presenting With Acute Chest Pain

This case report presents the diagnostic difficulties encountered by a 96-year-old woman with osteoporosis who experienced acute chest pain following minor trauma, eventually diagnosed with a sternal fracture. It highlights the nuanced presentation and diagnostic challenges associated with sternal fractures in older patients. Despite the prevalent use of chest radiography and computed tomography in acute trauma assessments, this case emphasizes their limitations, as both modalities initially failed to detect the sternal fracture. The successful identification of the fracture using ultrasound (US) underscores the utility of this modality in detecting subtle yet clinically significant injuries. This report advocates for a high index of suspicion for sternal fractures in older patients presenting with chest pain after minor trauma and suggests that US is a valuable, less invasive diagnostic tool. By illuminating the potential for minor trauma to cause major injury and the critical role of US in diagnosis, this case provides valuable insights into the management of sternal fractures in the geriatric population, urging clinicians to consider atypical presentations in diagnostic evaluations.

Awake sternal fixation; comparison of technical details and early results with sternal fixation methods performed via general anaesthesia

OBJECTIVES

Isolated sternal fractures are rare pathologies that rarely require surgical fixation. Although different fixation techniques are used, it is routinely performed under general anaesthesia. In our study, we aimed to share the details of the awake sternal fixation technique performed in our clinic and to compare the early results with sternal fixation methods performed under general anaesthesia.

METHODS

Between January 2009 and January 2023, 129 patients who were diagnosed with sternal fracture and who underwent investigations and follow-up in our clinic were evaluated retrospectively. Thirteen patients who underwent surgical fixation for isolated sternal fracture were included in the study. Patients were categorized according to fixation and anaesthetic technique; group 1: fixation with steel wire under general anaesthesia (n = 4), group 2: fixation with titanium plate-screw under general anaesthesia (n = 4) and group 3: fixation with awake titanium plate-screw with parasternal intercostal plane block (n = 5). Demographics, surgical indication, radiological findings, surgical incision, surgical time and hospital stay were statistically compared.

RESULTS

The mean age of the patients included in the study was 55.15 ± 15.01 years and 84.6% (n = 11) were male. The most common reason for fixation was displaced fracture (53.8%). Fixation surgery was performed due to pain in 30.8% (n = 4) and non-union in 15.4% (n = 2) of the fractures. The mean duration of surgery were 98.75 ± 16.52, 77.5 ± 35 and 41 ± 14.74 min, respectively. Duration of surgery was significantly lower in group 3 compared to the other groups (P = 0.012). The hospital stay duration for group 1 was 6 days, group 2 was 4 days and group 3 was 1 day. A notable difference was observed among all groups (P = 0.019).

CONCLUSIONS

Awake sternal fixation technique with titanium plate-screw system under superficial parasternal intercostal plane block is an easy and effective method for surgical treatment of isolated sternal fractures. This technique showed a direct positive effect on the duration of surgery and hospital stay.

Deep learning-based framework for segmentation of multiclass rib fractures in CT utilizing a multi-angle projection network

PURPOSE

Clinical rib fracture diagnosis via computed tomography (CT) screening has attracted much attention in recent years. However, automated and accurate segmentation solutions remain a challenging task due to the large sets of 3D CT data to deal with. Down-sampling is often required to face computer constraints, but the performance of the segmentation may decrease in this case.

METHODS

A new multi-angle projection network (MAPNet) method is proposed for accurately segmenting rib fractures by means of a deep learning approach. The proposed method incorporates multi-angle projection images to complementarily and comprehensively extract the rib characteristics using a rib extraction (RE) module and the fracture features using a fracture segmentation (FS) module. A multi-angle projection fusion (MPF) module is designed for fusing multi-angle spatial features. RESULTS: It is shown that MAPNet can capture more detailed rib fracture features than some commonly used segmentation networks. Our method achieves a better performance in accuracy (88.06 ± 6.97%), sensitivity (89.26 ± 5.69%), specificity (87.58% ± 7.66%) and in terms of classical criteria like dice (85.41 ± 3.35%), intersection over union (IoU, 80.37 ± 4.63%), and Hausdorff distance (HD, 4.34 ± 3.1).

CONCLUSION

We propose a rib fracture segmentation technique to deal with the problem of automatic fracture diagnosis. The proposed method avoids the down-sampling of 3D CT data through a projection technique. Experimental results show that it has excellent potential for clinical applications.

Traumatic sternal fractures: a narrative review

OBJECTIVE

Traumatic sternal fractures are injuries most commonly resulting from a direct blow to the anterior chest wall or forced deceleration. The purpose of this review is to define the clinical significance of these injuries, outline their initial evaluation and work up, and review current treatment strategies available and their outcomes.

BACKGROUND

The diagnosis of traumatic sternal fractures has seen a recent rise, largely due to the increased access to computed tomography (CT) scan. Currently, there are no published guidelines to make recommendations on operative fixation for sternal fractures. This is probably related to the lack of evidence in published literature along with patient heterogeneity.

METHODS

We conducted a non-systematic review of the English literature published from January 2000 to December 2020, including meta-analyses, systematic reviews, case series and case reports regarding the diagnosis, treatment, and complications of traumatic sternal fractures. We critically analyzed the available evidence to provide an overview of the treatment and clinical outcomes of traumatic sternal fractures.

CONCLUSION

Isolated sternal fractures are commonly benign injuries that can be managed conservatively in an outpatient setting. Polytrauma patients with sternal fractures should be carefully screened for possible associated injuries. Surgical stabilization of sternal fractures is feasible and safe, and should be considered in unstable fractures, severe displacement, symptomatic malunion or non-union.

A safe area for sternal puncture in children: an MSCT study based on sternal development

PURPOSE

Multislice spiral CT (MSCT) was used to investigate the anatomical characteristics of sternal development, and to provide anatomical basis for sternal puncture in children.

METHODS

We retrospectively analyzed the thoracic MSCT data of 600 children who received thoracic MSCT from January to June 2020 with their age ranging from 1 month to 19 years. The distribution of sternal ossification centers and adjacent tissues and organs was observed. Subcutaneous soft tissue thickness and the distance between the skin and the posterior margin of the sternum were measured in the central areas of sternal manubrium and mesosternum (segments I and II), and the correlation between the two was calculated using linear correlation.

RESULTS

A total of 600 patients were enrolled, the mean age was 9.87 years and the standard deviation was 8.28 years. The sternal manubrium and ossification centers at the I and II segments of the mesosternum were visible in all cases (100%). There was no ossification in segment III of the mesosternum in 15 cases (2.5%), including 12 cases (80%) adjacent to the posterior pericardium and 7 cases (46.7%) of lung tissue. There were 274 cases (45.7%) of segment IV without ossification, including 204 cases (74.5%) of adjacent pericardium and 95 cases (32.8%) of lung tissue. The xiphoid process was not ossified in 258 cases (43%), including 190 cases (73.6%) adjacent to the pericardium and 97 cases (37.6%) adjacent to the lung tissue. Correspondingly, the thickness of subcutaneous soft tissue of the sternal manubrium and the central region of the I and II segments of the mesosternum had a low positive correlation with age (P < 0.001), the distance between the skin and the posterior margin of the sternum showed a moderate positive correlation with age (P < 0.001), and the distance between the skin and the posterior margin of the sternum showed a high positive correlation with the thickness of subcutaneous soft tissue (P < 0.001).

CONCLUSIONS

Nonossification of the sternal ossification center usually occurs below segment III of the mesosternum and is usually adjacent to heart and lung tissue. Pediatric sternal puncture should be performed at the sternal manubrium and the mesosternum of segments I and II. However, attention should be paid to the space between multiple ossification centers. The thickness of subcutaneous soft tissue is a critical factor that determines the depth of the puncture.

Surgical treatment of sternum comminuted fracture with memory alloy embracing fixator

Background

Sternal fracture can result from multiple types of severe chest trauma and carries significant risk. Surgical fixation is an effective method for sternal fracture.

Methods

The clinical data of patients with sternal fractures who presented to our hospital between August 2016 and July 2019 were collected. The 42 patients were divided into three groups, with 15 patients treated by internal fixation with NI-TI memory alloy embracing fixator, 10 patients receiving steel wire fixation, and 17 who received non-surgical treatment and who was designated as a control (conservative) group. Differences in clinical indices included the duration of surgery, blood loss, hospitalization, wound healing, hospitalization expenses, VAS scores, and patient satisfaction scores between the three groups was compared. The analysis of variance and t-test were used for quantitative variables, which were approximately normally distributed. Dichotomous data were compared used Pearson χ² or Fisher’s exact test, and a P value less than 0.05 was considered as statistically significant.

Results

All patients were cured, and there were no significant differences in general clinical features between the three groups (P>0.05). Thoracic deformity in the surgical groups was corrected anatomically and received better pain scores, while patients in the NI-TI memory alloy embracing fixator group showed advantages of bleeding and patient satisfaction (P<0.05).

Conclusions

Operative treatment for a sternal fracture is safe, effective and can quickly restore the stability of the thorax. Memory alloy embracing fixator is markedly superior to other fixator materials.

Point-of-Care Ultrasound Used to Diagnose Sternal Fractures Missed by Conventional Imaging

ABSTRACT

Sternal fractures have often been associated with high-impact thoracic trauma. In children, this is not always the case. X-ray and even computed tomography can miss subtle sternal fractures. Point-of-care ultrasound has been shown to be more sensitive and specific for detecting subtle sternal fractures as compared with plain X-ray. The following 2 cases describe sternal fractures that were missed by traditional imaging modalities, including a fracture missed by chest computed tomography. They also highlight other potential causative mechanisms for sternal fractures in children, including hyperflexion injuries and low-mechanism motor vehicle accidents.

Automatic Detection and Classification of Rib Fractures on Thoracic CT Using Convolutional Neural Network: Accuracy and Feasibility

Objective

To evaluate the performance of a convolutional neural network (CNN) model that can automatically detect and classify rib fractures, and output structured reports from computed tomography (CT) images.

Materials and Methods

This study included 1079 patients (median age, 55 years; men, 718) from three hospitals, between January 2011 and January 2019, who were divided into a monocentric training set (n = 876; median age, 55 years; men, 582), five multicenter/multiparameter validation sets (n = 173; median age, 59 years; men, 118) with different slice thicknesses and image pixels, and a normal control set (n = 30; median age, 53 years; men, 18). Three classifications (fresh, healing, and old fracture) combined with fracture location (corresponding CT layers) were detected automatically and delivered in a structured report. Precision, recall, and F1-score were selected as metrics to measure the optimum CNN model. Detection/diagnosis time, precision, and sensitivity were employed to compare the diagnostic efficiency of the structured report and that of experienced radiologists.

Results

A total of 25054 annotations (fresh fracture, 10089; healing fracture, 10922; old fracture, 4043) were labelled for training (18584) and validation (6470). The detection efficiency was higher for fresh fractures and healing fractures than for old fractures (F1-scores, 0.849, 0.856, 0.770, respectively, p = 0.023 for each), and the robustness of the model was good in the five multicenter/multiparameter validation sets (all mean F1-scores > 0.8 except validation set 5 [512 × 512 pixels; F1-score = 0.757]). The precision of the five radiologists improved from 80.3% to 91.1%, and the sensitivity increased from 62.4% to 86.3% with artificial intelligence-assisted diagnosis. On average, the diagnosis time of the radiologists was reduced by 73.9 seconds.

Conclusion

Our CNN model for automatic rib fracture detection could assist radiologists in improving diagnostic efficiency, reducing diagnosis time and radiologists' workload.

Automatic detection and classification of rib fractures based on patients' CT images and clinical information via convolutional neural network

OBJECTIVE

To develop a convolutional neural network (CNN) model for the automatic detection and classification of rib fractures in actual clinical practice based on cross-modal data (clinical information and CT images).

MATERIALS

In this retrospective study, CT images and clinical information (age, sex and medical history) from 1020 participants were collected and divided into a single-centre training set (n = 760; age: 55.8 ± 13.4 years; men: 500), a single-centre testing set (n = 134; age: 53.1 ± 14.3 years; men: 90), and two independent multicentre testing sets from two different hospitals (n = 62, age: 57.97 ± 11.88, men: 41; n = 64, age: 57.40 ± 13.36, men: 35). A Faster Region-based CNN (Faster R-CNN) model was applied to integrate CT images and clinical information. Then, a result merging technique was used to convert 2D inferences into 3D lesion results. The diagnostic performance was assessed on the basis of the receiver operating characteristic (ROC) curve, free-response ROC (fROC) curve, precision, recall (sensitivity), F1-score, and diagnosis time. The classification performance was evaluated in terms of the area under the ROC curve (AUC), sensitivity, and specificity.

RESULTS

The CNN model showed improved performance on fresh, healing, and old fractures and yielded good classification performance for all three categories when both clinical information and CT images were used compared to the use of CT images alone. Compared with experienced radiologists, the CNN model achieved higher sensitivity (mean sensitivity: 0.95 > 0.77, 0.89 > 0.61 and 0.80 > 0.55), comparable precision (mean precision: 0.91 > 0.87, 0.84 > 0.77, and 0.95 > 0.70), and a shorter diagnosis time (average reduction of 126.15 s).

CONCLUSIONS

A CNN model combining CT images and clinical information can automatically detect and classify rib fractures with good performance and feasibility in actual clinical practice.

KEY POINTS

• The developed convolutional neural network (CNN) performed better in fresh, healing, and old fractures and yielded a good classification performance in three categories, if both (clinical information and CT images) were used compared to CT images alone. • The CNN model had a higher sensitivity and matched precision in three categories than experienced radiologists with a shorter diagnosis time in actual clinical practice.

Inter- and intra-observer variability of the AO/OTA classification for sternal fractures: a validation study

INTRODUCTION

Recently, a new classification system for sternal fractures has been published in the Journal of Orthopedic trauma by the Arbeitsgemeinschaft für Osteosynthesefragen (AO) foundation and the Orthopaedic Trauma Association (OTA). The aim of this study was to evaluate inter- and intra-observer variability of the AO/OTA classification for sternal fractures.

MATERIALS AND METHODS

Twenty multidetector computed tomography (CT) scans of patients with sternal fractures were classified independently by six senior and six junior orthopedic trauma surgeons of two level-1 trauma centers. Assessment was done on two occasions with an interval of 6 weeks. The kappa value was calculated to determine variability.

RESULTS

The inter-observer variability of the AO/OTA classification for sternal fractures showed fair-to-moderate agreement (kappa = 0.364). There was no significant difference between junior and senior surgeons. Analyses of the separate components of the classification demonstrated that agreement was lowest for classifying fracture type within the sternal body (kappa = 0.319) followed by manubrium (kappa = 0.525). The intra-observer variability showed moderate agreement with a mean kappa of 0.414.

CONCLUSION

The inter- and intra-observer variability of the AO/OTA classification for sternal fractures shows fair-to-moderate agreement. The overall performance of the classification might be improved with minor modifications.

LEVEL OF EVIDENCE

Diagnostic cross-sectional study (level I).

Improved identification of sternal injuries with multidetector computed tomography (MDCT): sagittal reconstructions

Chest computed tomography is acquired in the axial plane, but sternal injuries may be missed on axial images. This study hypothesized that sagittal sternal reconstruction images improve detection of sternal injury and radiologist's confidence in diagnosis compared to axial images. Five radiologists independently reviewed first axial images and on a different day sagittal images of a retrospective set of trauma cases recording presence/absence of a sternal injury and/or adjacent hematoma. The reviewer's confidence in the presence/absence of a sternal injury was assessed on a 5-point scale. Sagittal reconstructions generally yielded higher interreader agreement and confidence indices on statistical analysis.

[Imaging of blunt chest trauma]

CLINICAL/METHODOLOGICAL ISSUE

Blunt chest trauma is associated with high morbidity and mortality. Consequently, all patients should be evaluated radiologically after blunt chest trauma to allow timely and appropriate treatment.

STANDARD RADIOLOGICAL METHODS

Conventional chest radiographs and computed tomography (CT) are proven modalities with which to evaluate patients after blunt chest trauma.

METHODOLOGICAL INNOVATIONS

Over the last several years extended focused assessment with sonography for trauma (eFAST) has gained increasing importance for the initial assessment of seriously injured patients.

PRACTICAL RECOMMENDATIONS

In the acute phase of severely injured patients eFAST examinations are helpful to exclude pneumothorax, hemothorax and hemopericardium. Chest radiographs may also be used to diagnose a pneumothorax or hemothorax; however, the sensitivity is limited and CT is the diagnostic modality of choice to evaluate severely injured patients.

Sternal fracture in the age of pan-scan

STUDY OBJECTIVE

Widespread chest CT use in trauma evaluation may increase the diagnosis of minor sternal fracture (SF), making former teaching about SF obsolete. We sought to determine: (1) the frequency with which SF patients are diagnosed by CXR versus chest CT under current imaging protocols, (2) the frequency of surgical procedures related to SF diagnosis, (3) SF patient mortality and hospital length of stay comparing patients with isolated sternal fracture (ISF) and sternal fracture with other thoracic injury (SFOTI), and (4) the frequency and yield of cardiac contusion (CC) workups in SF patients.

METHODS

We analyzed charts and data of all SF patients enrolled from January 2009 to May 2013 in the NEXUS Chest and NEXUS Chest CT studies, two multi-centre observational cohorts of blunt trauma patients who received chest imaging for trauma evaluation.

RESULTS

Of the 14,553 patients in the NEXUS Chest and Chest CT cohorts, 292 (2.0%) were diagnosed with SF, and 94% of SF were visible on chest CT only. Only one patient (0.4%) had a surgical procedure related to SF diagnosis. Cardiac contusion was diagnosed in 7 (2.4%) of SF patients. SF patient mortality was low (3.8%) and not significantly different than the mortality of patients without SF (3.1%) [mean difference 0.7%; 95% confidence interval (CI) -1.0 to 3.5%]. Only 2 SF patient deaths (0.7%) were attributed to a cardiac cause. SFOTI patients had longer hospital stays but similar mortality to patients with ISF (mean difference 0.8%; 95% CI -4.7% to 12.0).

CONCLUSIONS

Most SF are seen on CT only and the vast majority are clinically insignificant with no change in treatment and low associated mortality. Workup for CC in SF patients is a low-yield practice. SF diagnostic and management guidelines should be updated to reflect modern CT-driven trauma evaluation protocols.

Multidetector computed tomography of chest trauma: indications, technique and interpretation

Background

Chest traumas are a significant cause of mortality and morbidity, especially in the younger population.MethodsDiagnostic imaging plays a key role in their management. Multidetector computed tomography (MDCT) is the most important imaging method in this field. Its advantages include especially high speed and high geometric resolution in any plane.ResultsThe method allows us to view large parts of the body with minimal motion artifacts and to create accurate multiplanar and three-dimensional (3D) reformations, which make the diagnosis significantly more accurate. Because of its advantages MDCT has become the first-choice method in high-energy traumas.ConclusionThis article summarises the position of MDCT in the diagnostic algorithm of chest injuries, technical aspects of the examination and imaging findings in traumas of the individual chest compartments.

Teaching Points

• Diagnostic imaging plays a key role in the management of high-energy chest trauma.

• MDCT is the most important imaging method in this kind of injury, as detailed information can be acquired in a short acquisition time.

• Multiplanar and three-dimensional (3D) reformattings make the diagnosis significantly more accurate.