The most important finding of our present retrospective study evaluating 3,209 multiply-injured patients is that operative stabilization of concomitant clavicle fractures in patients with thoracic trauma has decisive positive effects on clinically relevant outcome parameters.
In addition to the serious, life-threatening thoracic organ injuries, the bony chest wall is at great risk in multiply-injured patients . Affection of the clavicle is the third most common fracture in multiply-injured patients (10.4%), only surpassed by femoral (16.5%) and tibial (12.6%) fractures . Regarding all multiply-injured patients with bony injuries to the chest wall, an additional clavicular fracture is present in even 18.8% of the cases . Thus, clavicle fractures are common injuries in patients suffering from thoracic trauma.
Basic characteristics of our study cohort correspond to other studies describing the epidemiology of clavicle fractures in thoracic trauma, like the Dutch National Trauma Database  or a British collective from Leeds . In these populations patients were also predominantly male and had a mean age of 39.1 and 47.5 years, respectively. While our reported mean age of 49.0 years is slightly higher, their reported ISS was higher with 28.7 and 29.2, compared to our mean ISS of 22.9 [11, 28].
Similar to previously published data on thoracic trauma, motorcycle crashes could be identified as the most frequent injury mechanism for developing a severe thoracic trauma with a clavicle fracture [11, 14, 29, 30].
One concern in most studies dealing with multiply-injured patients suffering from thoracic trauma is the heterogeneous patient collective regarding the leading injury and the immanent implication on the intensive care course (e.g. periods of mechanical ventilation in severe head trauma). By deliberately excluding more than moderate brain injuries in our patient collective, we sought to limit this risk of bias.
It has been suggested that patients sustaining serious trauma to the chest and suffering from three or more rib fractures should be transferred to a high-volume level 1 trauma center [31, 32]. In line with this recommendation, our patients were treated mainly at level 1 and level 2 trauma centers (98.3%).
In 42.0% of cases the clavicular fracture was treated operatively. A study with older data reviewing the years 2002–2013 in the TraumaRegister DGU® described an even higher rate of 52.4% operative treatments , which might be due to more generous inclusion criteria, as all patients with an ISS ≥ 16 were included.
Our reported patients suffering from thoracic trauma and clavicle fracture showed a prolonged period of ICU stay (mean 9.4 days) and intubation time (mean 7.4 days) compared to published multiply-injured patients without thoracic trauma (ICU: 8.1 days, intubation time: 3.9 days) . Yet, our findings are comparable with previously published data on patients with thoracic trauma (ICU: 11 days, intubation time: 7 days ; ICU: 12 days, intubation time: 7 days ).
In expert opinions and small case series, several authors recommend surgical stabilization of clavicular fractures in thoracic trauma, particularly in the case of displaced fractures and associated serial rib fractures or flail chest injuries [10, 35]. However, to the best of our knowledge, the implication of surgical management of clavicle fractures in thoracic trauma on clinical outcome parameters had yet to be evaluated. This is therefore the first study addressing the impact of operative treatment of the clavicle fracture in patients with relevant thoracic trauma on outcome parameters in a large collective. There are various theoretical reasons supporting surgical stabilization in this subgroup.
In patients with high-energy mechanism of injury clavicle fractures are prone to fracture displacement, also when initial imaging shows nondisplacement [36, 37].
Since the clavicle acts as a stabilizer of the upper quadrant of the chest fracture displacement is causing pain, especially in patients with concomitant ipsilateral rib fractures. The skeleton of the shoulder and chest loses stability and can lead to a loss of function of the shoulder and a pronounced deformation of the chest wall .
In particular, the breathing mechanism is affected. A fractured and instable clavicle as the origin of the accessory inspiratory muscles (M. sternocleidomastoideus, Mm. scaleni, M. pectoralis) can cause an ineffective respiration and oxygenation [16, 17].
In combination with a severe thoracic trauma it can thereby further the development of multiple organ dysfunction and pulmonary failure [38, 39]. Furthermore, it is well known that 80% of patients with multiple organ failure start with lung failure , and that severe thoracic trauma is an independent risk factor for developing multiple organ failure [40, 41],
To support the thesis that surgical fixation of fractures to the thoracic wall (or origins of inspiratory muscles) can support patient recovery in thoracic trauma several studies of rib fracture fixation have been published. Concerning flail chest injuries there is valid data supporting operative care of the injury to stabilize the thoracic aperture. Flail chest occurs when three or more adjacent ribs are fractured in at least two places, creating a chest wall segment that moves paradoxically from the chest wall , The operative treatment of flail chest injuries shows a clear advantage with regard to the clinical course and outcomes in polytrauma [13, 42]. According to the metaanalysis of Leinicke et al. patients with early stabilization have less intubation time and both the length of stay in the intensive care unit and the total length of stay in the hospital could be significantly reduced by surgical therapy .
In our present study we are the first to demonstrate similar results concerning surgical stabilization of clavicle fractures.
80.9% of our patients suffered from at least serious thoracic trauma (AISThorax ≥ 3). Therefore, to analyze the effect of operative treatment of the clavicle fracture for all thoracic trauma patients the independent variable AISThorax was included into to the regression model. We also included other possible confounders (age, sex, ISS, AISHead, AISThorax, AISAbdomen, AISExtremities, shock RRsyst <90 mmHg, intubation and blood transfusion) as independent variables into the regression model, and therefore sought to control for confounding.
Surgically treated patients showed a significantly reduced intubation time and length of hospital stay compared to conservative care. Furthermore, the risk of lung failure and multiple organ failure was significantly reduced. Mortality was eminently lower in the operative subgroup. Nevertheless, the reduction in mortality in our data should not be overestimated, because combinations of injuries or comorbidities with a clinically relevant likelihood of mortality can be a reason for not undergoing surgery and therefore pose a bias towards higher mortality in the conservatively treated subgroup.
In our study, the influence of surgical clavicle stabilization on sepsis and length of ICU-stay was not statistically significant. One reason for that finding could be that these variables might be eminently influenced by other major injuries besides the thoracic trauma.
According to our results, operative management of clavicle fractures in thoracic trauma might therefore be a promising treatment strategy that improves patient’s outcome, and also lower treatment costs due to less complications and total days in hospital. Yet, these positive results come with the cost of an operative intervention.
But, complications of surgical treatment of clavicle fractures are rare. In a retrospective review of 1,350 clavicular internal fixations, by plate or intramedullary fixation, Leroux et al. reported neurovascular complications to be exceptional, with only 5 neurologic and 5 vascular complications: i.e., < 1% . A systematic review of Rehn et al. found a prevalence of complications that required additional major surgery of 3.3% in the operative groups compared to 8.6% in the non-operative groups .
As shown in other studies surgical timing and early operative treatment may result in positive implications for the intensive care unit stay and clinical outcome [45, 46]. In line with studies showing benefits in organ failure reduction and shortening of intubation periods after early operative treatment of fractures in different body regions we are the first to describe this effect in early stabilization of clavicle fractures in thoracic trauma patients.
This study is limited by the nature of a registry study. Hospitals participating in the TR-DGU® are regularly audited, and sample tests are taken to ensure data quality. However, the validity of their documentation is not verified by external monitors as in prospective trials .
We excluded patients with more than moderate head injury (AIS ≥ 3) in our study to minimize confounding and, as a result, our findings cannot be readily transferred to severely injured patients sustaining additional major trauma to this body region. We are not able to comment on the performed surgical procedures (e.g. plate osteosynthesis, elastic stable intramedullary nailing, etc.) and treatment protocols, since this information is not available in the TR-DGU® database.
Additionally, we are unable to comment on the fracture morphology, displacement and fractured part of the clavicle, since this information is not available in the TR-DGU® database, either. Therefore, we were unable to include this information in our statistical regression model.
There is an ongoing discussion on the management of multiply-injured patients and timing of osteosynthesis . For small bone fractures no recommendations or studies exist on when to surgically stabilize these injuries in multiply injured patients. For long bone and spinal fractures research exists and some favor stabilization within 72 hours after hospital admission [45, 46]. Since long bone and spinal fractures are more relevant to patient management on the ICU and are preferably stabilized before small bone fractures, we concluded to examine the time for early clavicular stabilization until 5 days after hospital admission. Although, as mentioned above, this timing is chosen in lack of scientific evidence we based our decision on reasonable clinical experience.
Besides the above stated limitations, to the best of our knowledge, we are the first study group to present comprehensive data on clavicle surgery and timing in multiply- injured patients suffering from concomitant thoracic trauma.