High sensitivity methods for automated rib fracture detection in pediatric radiographs.

Rib fractures are highly predictive of non-accidental trauma in children under 3 years old. Rib fracture detection in pediatric radiographs is challenging because fractures can be obliquely oriented to the imaging detector, obfuscated by other structures, incomplete, and non-displaced. Prior studies have shown up to two-thirds of rib fractures may be missed during initial interpretation. In this paper, we implemented methods for improving the sensitivity (i.e. recall) performance for detecting and localizing rib fractures in pediatric chest radiographs to help augment performance of radiology interpretation. These methods adapted two convolutional neural network (CNN) architectures, RetinaNet and YOLOv5, and our previously proposed decision scheme, "avalanche decision", that dynamically reduces the acceptance threshold for proposed regions in each image. Additionally, we present contributions of using multiple image pre-processing and model ensembling techniques. Using a custom dataset of 1109 pediatric chest radiographs manually labeled by seven pediatric radiologists, we performed 10-fold cross-validation and reported detection performance using several metrics, including F2 score which summarizes precision and recall for high-sensitivity tasks. Our best performing model used three ensembled YOLOv5 models with varied input processing and an avalanche decision scheme, achieving an F2 score of 0.725 ± 0.012. Expert inter-reader performance yielded an F2 score of 0.732. Results demonstrate that our combination of sensitivity-driving methods provides object detector performance approaching the capabilities of expert human readers, suggesting that these methods may provide a viable approach to identify all rib fractures.

Rib and sternum fracture risks for restrained occupants in frontal car crashes.

OBJECTIVE: Most car occupant fatalities occur in frontal crashes and the thorax is the most frequently injured body region. The objectives of the study were, firstly, to quantify the relation between risk factors (such as speed and occupant age) and rib and sternum fracture injury probability in frontal car crashes, and, secondly, to evaluate whether rib fracture occurrence can predict sternum fractures. METHODS: Weighted German data from 1999-2021 were used to create the injury risk curves to predict both, at least moderate and at least serious, rib and sternum fracture risks. A contingency table for rib and sternum fractures allowed the calculation of sensitivity, specificity, and precision, as well as testing for the association. RESULTS: Elderly occupants (≥65 years old) had increased rib and sternum fracture risk compared to mid aged occupants (18-64 years old). Besides occupant age, delta-V was always and sex sometimes a significant predictor for skeletal thoracic injury. Sternum fractures were more common than rib fractures and more likely to occur at any given delta-V. Sternum fractures occurred often in isolation. Female occupants were at higher risk than males to sustain at least moderate rib and sternum fractures together and sternum fractures in isolation. Rib and sternum fractures were associated, but low sensitivity and precision show that rib fractures do not predict sternum fractures well. CONCLUSIONS: Elderly and female occupants were at the highest risk and should be targeted by thoracic injury criteria and thresholds for frontal crash occupant protection. Rib and sternum fractures were not associated. Therefore, sternum fractures need to be predicted and evaluated separately from rib fractures.

Explaining and predicting the increased thorax injury in aged females: age and subject-specific thorax geometry coupled with improved bone constitutive models and age-specific material properties evaluated in side impact conditions.

Predicting and understanding thorax injury is fundamental for the assessment and development of safety systems to mitigate injury risk to the increasing and vulnerable aged population. While computational human models have contributed to the understanding of injury biomechanics, contemporary human body models have struggled to predict rib fractures and explain the increased incidence of injury in the aged population. The present study enhanced young and aged human body models (HBMs) by integrating a biofidelic cortical bone constitutive model and population-based bone material properties. The HBMs were evaluated using side impact sled tests assessed using chest compression and number of rib fractures. The increase in thoracic kyphosis and the associated change in rib angle with increasing age, led to increased rib torsional moment increasing the rib shear stress. Coupled with and improved cortical bone constitutive model and aged material properties, the higher resulting shear stress led to an increased number of rib fractures in the aged model. The importance of shear stress resulting from torsional load was further investigated using an isolated rib model. In contrast, HBM chest compression, a common thorax injury-associated metric, was insensitive to the aging factors studied. This study proposes an explanation for the increased incidence of thorax injury with increasing age reported in epidemiological data, and provides an enhanced understanding of human rib mechanics that will benefit assessment and design of future safety systems.

Pulmonary fat embolism in non-survivors after cardiopulmonary resuscitation.

BACKGROUND: Blunt trauma acting against the human body presents the fundamental cause of pulmonary fat embolism (PFE) and fat embolism syndrome. The aim of the present study was to investigate PFE in non-survivors after cardiopulmonary resuscitation (CPR). METHODS: This was a prospective cohort study conducted in University Hospital Ostrava, Czech Republic. Within a 4-year study period, all non-survivors after CPR because of out-of-hospital cardiac arrest were assessed for the study eligibility. The presence/seriousness of PFE was determined by microscopic examination of cryo-sections of lung tissue (staining with Oil Red O). RESULTS: In total, 106 persons after unsuccessful CPR were enrolled in the study. The most frequent cause of death in the study population (63.2% of cases) was cardiac disease (ischemic heart disease); PFE was not determined as the cause of death in any of our study cases. Sternal fractures were identified 66.9%, rib fractures (usually multiple) in 80.2% of study cases; the median number of rib fractures was 10.2 fractures per person. Serious intra-thoracic injuries were found in 34.9% of cases. Microscopic examination of lung cryo-sections revealed PFE in 40 (37.7%) study cases; PFE was most frequently evaluated as grade I or II. Occurrence of sternal and rib fractures was significantly higher in persons with PFE than between persons without PFE (p = 0.033 and p = <0.001). Number of rib fractures was also significantly higher in persons with PFE. The occurrence of serious intra-thoracic injuries was comparable in both our study groups (p = 0.089). CONCLUSIONS: PFE presents a common resuscitation injury which can be found in more than 30% of persons after CPR. Persons with resuscitation skeletal chest fractures have significantly higher risk of PFE development. During autopsy of persons after unsuccessful CPR, it is necessary to distinguish CPR-associated injuries including PFE from injuries that arise from other mechanisms.

Management of Blunt Chest Trauma.

Common mechanisms of blunt thoracic injury include motor vehicle collisions and falls. Chest wall injuries include rib fractures and sternal fractures; treatment involves supportive care, multimodal analgesia, and pulmonary toilet. Pneumothorax, hemothorax, and pulmonary contusions are also common and may be managed expectantly or with tube thoracostomy as indicated. Surgical treatment may be considered in select cases. Less common injury patterns include blunt trauma to the tracheobronchial tree, esophagus, diaphragm, heart, or aorta. Operative intervention is more often required to address these injuries.

Breaking point? An analysis of fatal stab wounds to the torso in Ireland between 2011 and 2018, examining the extent of rib fractures.

This study examines the pattern of rib injuries occurring in cases of fatal torso stab wounds in Ireland between 2011 and 2018. It has been suggested by previous studies that rib fractures are not commonly sustained in stab wounds to the torso. We wanted to ascertain whether this was the case, as our data suggested that rib fractures were frequent, and where a rib is fractured there is a higher chance of organ injury and death, making this an important area of study. One hundred and forty seven cases of fatal stab wounds from an eight-year period were retrospectively reviewed. Fatal stab wounds to other body areas, were excluded; leaving a total of 104 cases with stab wounds to the torso. We found that 69.2% of cases had rib injuries, a figure significantly higher than previously reported. Our data suggests that stab wounds to the torso often fracture ribs, putting the underlying organs at increased risk of injury and perhaps contributing to fatality. The amount of force needed to cause a rib fracture can be difficult to quantify and indeed from the high percentage of rib fractures sustained in our data it appears that the ribs may be fractured regardless of the amount of force used; this is borne out by the finding that self-inflicted injuries also caused rib fractures. Our study shows that other factors, such as anatomical positioning and wound depth may have a greater bearing than force in terms of whether a rib fracture is sustained.

Motor Vehicle Protective Device Usage Associated with Decreased Rate of Flail Chest: A Retrospective Database Analysis.

Background and Objectives: Protective equipment, including seatbelts and airbags, have dramatically reduced the morbidity and mortality rates associated with motor vehicle collisions (MVCs). While generally associated with a reduced rate of injury, the effect of motor vehicle protective equipment on patterns of chest wall trauma is unknown. We hypothesized that protective equipment would affect the rate of flail chest after an MVC. Materials and Methods: This study was a retrospective analysis of the 2019 iteration of the American College of Surgeons Trauma Quality Program (ACS-TQIP) database. Rib fracture types were categorized as non-flail chest rib fractures and flail chest using ICD-10 diagnosis coding. The primary outcome was the occurrence of flail chests after motor vehicle collisions. The protective equipment evaluated were seatbelts and airbags. We performed bivariate and multivariate logistic regression to determine the association of flail chest with the utilization of vehicle protective equipment. Results: We identified 25,101 patients with rib fractures after motor vehicle collisions. In bivariate analysis, the severity of the rib fractures was associated with seatbelt type, airbag status, smoking history, and history of cerebrovascular accident (CVA). In multivariate analysis, seatbelt use and airbag deployment (OR 0.76 CI 0.65-0.89) were independently associated with a decreased rate of flail chest. In an interaction analysis, flail chest was only reduced when a lap belt was used in combination with the deployed airbag (OR 0.59 CI 0.43-0.80) when a shoulder belt was used without airbag deployment (0.69 CI 0.49-0.97), or when a shoulder belt was used with airbag deployment (0.57 CI 0.46-0.70). Conclusions: Although motor vehicle protective equipment is associated with a decreased rate of flail chest after a motor vehicle collision, the benefit is only observed when lap belts and airbags are used simultaneously or when a shoulder belt is used. These data highlight the importance of occupant seatbelt compliance and suggest the effect of motor vehicle restraint systems in reducing severe chest wall injuries.

If we should remove internal fixation devices for rib fractures?

BACKGROUND: Internal fixation for rib fractures has been widely carried out worldwide, and its surgical efficacy has been recognized. However, there is still controversy about whether implant materials need to be removed. At present, the research on this topic is still lacking at home and abroad. Therefore, in this study, the patients undergoing removal of internal fixation for rib fractures in our department within one year were followed up, to statistically analyze implant-related complications, postoperative complications and postoperative remission rate. METHODS: A retrospective analysis was conducted on 143 patients undergoing removal of internal fixation for rib fractures from 2020 to 2021 in our center. The implant-related complications, postoperative complications and postoperative remission rate of patients with internal fixation were analyzed. RESULTS: In this study, a total of 143 patients underwent removal of internal fixation, among which 73 suffered from preoperative implant-related complications (foreign-body sensation, pain, wound numbness, sense of tightness, screw slippage, chest tightness, implant rejection), and 70 had no post operative discomfort but asked for removal of internal fixation. The average interval between rib fixation and removal was 17 ± 9.00 (months), and the average number of removed materials was 5.29 ± 2.42. Postoperative complications included wound infection (n = 1) and pulmonary embolism (n = 1). of the 73 patients with preoperative implant-related complications, the mean postoperative remission rate was 82%. Among the 70 patients without preoperative discomfort, the proportion of discomforts after removal was 10%. No perioperative death occurred. CONCLUSION: For patients with internal fixation for rib fractures, removal of internal fixation can be considered in the case of implant-related complications after surgery. The corresponding symptoms can be relieved after removal. The removal presents low complication rate, and high safety and reliability. For patients without obvious symptoms, it is safe to retain the internal fixation in the body. For the asymptomatic patients who ask for removal of internal fixation, the possible risk of complications should be fully informed before removal.

Injury pattern and clinical outcome in patients with and without chest wall injury after cardiopulmonary resuscitation.

BACKGROUND: Cardiopulmonary resuscitation (CPR), although lifesaving may cause chest wall injury (CWI) because of the physical force exerted on the thorax. The impact of CWI on clinical outcome in this patient group is unclear. The primary aim of this study was to investigate the incidence of CPR-related CWI and the secondary aim to study injury pattern, length of stay (LOS), and mortality in patients with and without CWI. METHODS: This is a retrospective study of adult patients who were admitted to our hospital due to cardiac arrest (CA) during 2012 to 2020. Patients were identified in the Swedish CPR Registry and those undergoing CT of the thorax within 2 weeks after CPR were included. Patients with traumatic CA, chest wall surgery prior or after CA were excluded. Demographic data, type and length of CPR, type of CWI, LOS on mechanical ventilator (MV), in intensive care unit (ICU) and in hospital (H), and mortality were studied. RESULTS: Of 1,715 CA patients, 245 met the criteria for inclusion. The majority (79%) of the patients suffered from CWI. Chondral injuries and rib fractures were more common than sternum fractures (95% vs. 57%), and 14% had a radiological flail segment. Patients with CWI were older (66.5 ± 15.4 vs. 52.5 ± 15.2, p < 0.001). No difference was seen in MV-LOS (3 [0-43] vs. 3 [0-22]; p = 0.430), ICU-LOS (3 [0-48] vs. 3 [0-24]; p = 0.427), and H-LOS (5.5 [0-85] vs. 9.0 [1-53]; p = 0.306) in patients with or without CWI. Overall mortality within 30 days was higher with CWI (68% vs. 47%, p = 0.007). CONCLUSION: Chest wall injuries are common after CPR and 14% of patients had a flail segment on CT. Elderly patients have an increased risk of CWI, and a higher overall mortality is seen in patients with CWI. LEVEL OF EVIDENCE: Prognostic and Epidemiological; Level IV.

Analysis of injury mechanism and thoracic response of elderly, small female PMHS in near-side impact scenarios.

OBJECTIVE: In 2020, 17% of all crash fatalities were individuals aged 65 years or older. Crash data also revealed that for older occupants, thoracic related injuries are among the leading causes of fatality. Historically, the majority of near-side impact postmortem human subjects (PMHS) studies used a generic load wall to capture external loads that were applied to PMHS. While these data were helpful in documenting biofidelity, they did not represent a realistic response an occupant would undergo in a near-side crash. The objective of this research was to test small, elderly female PMHS in a repeatable, realistic near-side impact crash scenario to investigate current injury criteria as they relate to this vulnerable population. METHOD: Ten small, elderly PMHS were subjected to a realistic near-side impact loading condition. The PMHS were targeted to be elderly females age 60+, approximately 5th percentile in height and weight, with osteopenic areal bone mineral density. Each subject was seated on a mass-production seat, equipped with a side airbag and standard three-point restraint with a pretensioner. Other boundary conditions included an intruding driver's side door. PMHS instrumentation included strain gages on ribs 3-10 bilaterally to identify fracture timing. Two chestbands were used to measure chest deflection, one at the level of the axilla and one at the level of the xiphoid process. RESULTS: Injuries observed included rib fractures, particularly on the struck side, and in multiple cases a flail chest was observed. Eight of ten subjects resulted in AIS3+ thoracic injuries, despite previously tested ATDs predicting less than a 10% chance of AIS3+ injury. Subjects crossed the threshold for AIS3 injury in the range of only 1% - 9% chest compression. Additionally, mechanisms of injury varied, as some injuries were incurred by door interactions while others came during airbag interactions. CONCLUSIONS: This research points to two areas of concern that likely require further analysis: (1) the appropriateness of potentially oversimplified PMHS testing to establish injury thresholds and define injury criteria for complicated crash scenarios; (2) the importance of identifying the precise timing of injuries to better understand the effect of current passive restraint systems.

Thoracic responses and injuries to male postmortem human subjects (PMHS) in rear-facing seat configurations in high-speed frontal impacts.

Objective: One potential nonstandard seating configuration for vehicles with automated driving systems (ADS) is a reclined seat that is rear-facing when in a frontal collision. There are limited biomechanical response and injury data for this seating configuration during high-speed collisions. The main objective of this study was to investigate thoracic biomechanical responses and injuries to male postmortem human subjects (PMHS) in a rear-facing scenario with varying boundary conditions.Method: Fourteen rear-facing male PMHS tests (10 previously published and 4 newly tested) were conducted at two different recline angles (25-degree and 45-degree) in 56 km/h frontal impacts. PMHS were seated in two different seats; one used a Fixed D-Ring (FDR) seat belt assembly and one used an All Belts To Seat (ABTS) restraint. For thoracic instrumentation, strain gages were attached to ribs to quantify strain and fracture timing. A chestband was installed at the mid-sternum level to quantify anterior-posterior (AP) chest deflections. Data from the thorax instrumentation were analyzed to investigate injury mechanisms.Results: The PMHS sustained a greater number of rib fractures (NRF) in the 45-degree recline condition (12 ± 7 NRF for ABTS45 and 25 ± 18 NRF for FDR45) than the 25-degree condition (6 ± 4 NRF for ABTS25 and 12 ± 8 NRF for FDR25), despite AP chest compressions in the 45-degree condition (-23.7 ± 9.4 mm for ABTS45 and -39.6 ± 11.9 mm for FDR45) being smaller than the 25-degree condition (-38.9 ± 16.9 mm for ABTS25 and -55.0 ± 4.4 mm for FDR25). The rib fractures from the ABTS condition were not as symmetric as the FDR condition in the 25-degree recline angle due to a belt retractor structure located at one side of the seatback frame. Average peak AP chest compression occurred at 45.7 ± 3.4 ms for ABTS45, 45.6 ± 3.1 ms for FDR45, 46.7 ± 1.9 ms for ABTS25, and 46.9 ± 2.3 ms for FDR25. Average peak seatback resultant force occurred at 43.9 ± 0.9 ms for ABTS45, 44.6 ± 0.8 ms for FDR45, 42.5 ± 0.2 ms for ABTS25, and 41.5 ± 0.5 ms for FDR25. The majority of rib fractures occurred after peak AP chest compression and peak seatback resultant force likely due to the ramping motion of the PMHS, which might create a combined loading (e.g., AP deflection and upward deflection) to the thorax. Although NRF in the 45-degree reclined condition was greater than the 25-degree recline condition, similar magnitudes of rib strains were observed regardless of seat and restraint types, while strain modes varied.Conclusions: The majority of rib fractures occurred after peak AP chest compression and peak seatback force, especially in FDR25, ABTS45, and FDR45, while the PMHS ramped up along the seatback. AP chest compression, seatback load, and strain measured along the rib could not explain the greater NRF in the 45-degree recline conditions. A complex combination of AP chest deflection with upward deflection was discovered as a possible mechanism for rib fractures in PMHS subjected to rear-facing frontal impacts in this study.

Predictors and characteristics of Rib fracture following SBRT for lung tumors.

BACKGROUND: The utilization of stereotactic body radiation therapy (SBRT) is increasing for primary and secondary lung neoplasms. Despite encouraging results, SBRT is associated with an increased risk of osteoradionecrosis-induced rib fracture. We aimed to (1) evaluate potential clinical, demographic, and procedure-related risk factors for rib fractures and (2) describe the radiographic features of post-SBRT rib fractures. METHODS: We retrospectively identified 106 patients who received SBRT between 2015 and 2018 for a primary or metastatic lung tumor with at least 12 months of follow up. Exclusion criteria were incomplete records, previous ipsilateral thoracic radiation, or relevant prior trauma. Computed tomography (CT) images were reviewed to identify and characterize rib fractures. Multivariate logistic regression modeling was employed to determine clinical, demographic, and procedural risk factors (e.g., age, sex, race, medical comorbidities, dosage, and tumor location). RESULTS: A total of 106 patients with 111 treated tumors met the inclusion criteria, 35 (32%) of whom developed at least one fractured rib (60 total fractured ribs). The highest number of fractured ribs per patient was five. Multivariate regression identified posterolateral tumor location as the only independent risk factor for rib fracture. On CT, fractures showed discontinuity between healing edges in 77% of affected patients. CONCLUSIONS: Nearly one third of patients receiving SBRT for lung tumors experienced rib fractures, 34% of whom experienced pain. Many patients developed multiple fractures. Post-SBRT fractures demonstrated a unique discontinuity between the healing edges of the rib, a distinct feature of post-SBRT rib fractures. The only independent predictor of rib fracture was tumor location along the posterolateral chest wall. Given its increasing frequency of use, describing the risk profile of SBRT is vital to ensure patient safety and adequately inform patient expectations.

A retrospective study of adjuvant proton radiotherapy for breast cancer after lumpectomy: a comparison of conventional-dose and hypofractionated dose.

PURPOSE: This study aimed to compare the adverse reactions of conventional-dose and hypofractionated dose of proton therapy for breast cancer. MATERIALS AND METHODS: Breast cancer patients treated with proton radiotherapy in conventional-dose or hypofractionated dose were studied retrospectively. RESULT: From January 2017 to December 2019, our center treated 50 patients following lumpectomy with proton radiotherapy. According to the AJCC 8th Edition standard, there were stage I in 26 patients, stage II in 22 patients, and stage III in 2 patients. A total of 14 patients received intensity-modulated proton therapy at a dose of 50 Gy in 25 fractions, followed by a 10 Gy 4 fractionated boost to the lumpectomy cavity, while 36 received 40.05 Gy in 15 fractions, simultaneous integrated boost (SIB) 48 Gy to the lumpectomy cavity. Median follow-up time for 40.05 Gy group was 35.6 months (15-43 months). Median follow-up time for 50 Gy group was 46.8 months (36-68 months). For acute toxicity, the grade 1 and 2 radiodermatitis in conventional-dose group were 35.7% and 57.1%, respectively. In hypofractionated dose group, the grade 1 and 2 radiodermatitis were 91.7% and 8.3%, respectively. The radiodermatitis is hypofractionneted dose better than conventional-dose significantly. Grade 1 radiation-induced esophagitis in conventional-dose group and hypofractionated dose group were 85.71% and 60%, respectively. For late toxicity, no patients developed radiation-induced pneumonitis and rib fracture in conventional-dose group. Three patients presented grade 1 pneumonitis; one patient presented graded 2 pneumonitides and two patients presented rib fracture in hypofractionated dose group. One presented hypothyroidism in hypofractionated dose group. All patients were satisfied with breast shape. The one- and two-year OS and DFS for conventional-dose group were 100 and 100; 100 and 92.9%, respectively. The one- and two-year OS and DFS for hypofractionated dose group were 100 and 100; 100 and 100%, respectively. CONCLUSION: Proton radiation therapy can significantly reduce the normal tissue dose in breast cancer patients' hearts, lungs, and other organs. Hypofractionated proton therapy shortens the treatment course with mild radiation-related adverse effects, and has a better effect on addressing the acute adverse reactions than conventional proton radiotherapy.

Brachial plexus injury and upper rib fracture after median sternotomy in cardiac surgery.

OBJECTIVES: Sternal retractors utilized during open-heart surgeries through median sternotomy can cause upper rib fractures which sometimes further leads to brachial plexus injury. We aimed to investigate the incidence of brachial plexus injury and upper rib fractures in open-heart surgeries and how these injuries are associated with each other. METHODS: We investigated 1050 cases during the past five years. The incidence of brachial plexus injury and upper rib fractures after median sternotomy was assessed in all patients and the patients who sustained were evaluated for the affected side, the level of paralysis. RESULTS: Ten cases (0.95%) exhibited brachial plexus injury after median sternotomy. Nine cases developed paralysis on left upper extremity. In all ten cases, sensory and motor nerve impairment were exhibited in the lower plexus. Rib fractures were observed in 35.0% of cases after median sternotomy and the usage of asymmetric sternal retractors to harvest left internal thoracic artery (LITA) significantly affected the side of fracture. CONCLUSION: Sternal retractors utilized during open-heart surgeries through median sternotomy may cause rib fractures and brachial plexus injury, so operators should be aware of these complications.

Near-maximum rib dose is the most relevant risk factor for ipsilateral spontaneous rib fracture: a dosimetric analysis of breast cancer patients after radiotherapy.

PURPOSE: Spontaneous rib fracture (SRF) is a common late complication in treated breast cancer patients. This study evaluated the incidence and risk factors of ipsilateral SRF after radiotherapy (RT) in breast cancer patients. In addition, we identified dosimetric parameters that were significantly associated with ipsilateral SRF. METHODS: We retrospectively reviewed 2204 patients with breast cancer who underwent RT between 2014 and 2016, and were followed up with bone scans. We evaluated clinical risk factors for ipsilateral SRF. Dose-volume histogram analysis was also performed for patients (n = 538) whose dosimetric data were available. All ipsilateral ribs were manually delineated, and dosimetric parameters of the ribs were converted into the equivalent dose in 2 Gy fractions (EQD2). RESULTS: Most of the patients with SRF (87.3%) were asymptomatic, and the remaining symptomatic patients complained of mild tenderness or chest wall discomfort; these symptoms all resolved within 6 months without any treatment. Ipsilateral SRF occurred in 14.5% of patients 3 years after RT. The median time to develop ipsilateral SRF was 15 months. In dosimetric analysis, near-maximum rib dose (D2cc) best predicted ipsilateral SRF. The cut-off value of D2cc was EQD2 52 Gy, as determined by receiver operating characteristic analysis. In multivariate analysis including dosimetric variables, D2cc EQD2 ≥ 52 Gy was the only significant risk factor for ipsilateral SRF. CONCLUSION: Our data demonstrated that near-maximum rib dose was the best dosimetric parameter to predict ipsilateral SRF in RT-treated breast cancer patients. In addition, our results suggest that patients who received RT with exceeding rib dose cut-off value and had ipsilateral SRF on bone scan be recommended routine follow-up without additional imaging tests.

Rib fractures in adult horses as a cause of poor performance; diagnosis, treatment and outcome in 73 horses.

BACKGROUND: Rib fractures in adult horses are poorly documented. OBJECTIVES: To describe the presenting signs, diagnosis, treatment and outcome of horses diagnosed with rib fracture. STUDY DESIGN: Retrospective case series. METHOD: The clinical records and diagnostic images of all adult horses diagnosed with a rib fracture at three referral centres over a 15-year period were reviewed. RESULTS: Seventy-three horses met the inclusion criteria. Horses presented due to either resistance to ridden work and poor performance (n = 41), lameness (n = 21) or trauma (n = 7). In four horses, the presenting complaint was not recorded. Clinical assessment and palpation localised the site of injury in 18/47 cases where recorded. Nuclear scintigraphic examination identified all fracture sites in which it was performed (59/59). In 10/24 horses, radiographic examination confirmed rib fracture. Ultrasonographic examination confirmed rib fracture in 58/59 horses (98%; 95% CI 92-100). Six horses underwent surgery due to ongoing clinical signs and non-healing fracture; all other horses were managed conservatively. Fifty-five horses were available for long-term follow up (>1 year), of which 28 (51%; 95% CI 38-64) returned to their previous level of exercise. Twelve horses did not return to their previous level of exercise due to lameness unrelated to the rib fracture and seven horses were subjected to euthanasia, of which three were as a result of the rib fracture. Eight horses did not return to their previous level of exercise for other reasons. MAIN LIMITATIONS: Incomplete data set due to retrospective case series. CONCLUSIONS: Although uncommon, rib fractures should be considered in cases of reduced performance or resistance during ridden exercise. Palpation may be unrewarding. Scintigraphy and ultrasonography are useful in identifying the fracture site. Rib fractures in horses carry a fair prognosis and can be managed conservatively in most cases.