Matthias Russ

Predictors of mortality following severe pelvic ring fracture: Results of a population-based study

INTRODUCTION Traumatic disruption of the pelvic ring is uncommon but is associated with a high risk of mortality. These injuries are predominantly due to high energy blunt trauma such as a fall from height, road or workplace trauma, and severe associated injuries are prevalent, increasing the complexity of managing this patient group. The aim of this population-based study was to investigate predictors of mortality following severe pelvic ring fractures managed in an inclusive, regionalised trauma system. METHODS Cases aged≥15 years from 1st July 2001 to 30th June 2008 were extracted from the population-based statewide Victorian State Trauma Registry for analysis. Patient demographic, prehospital and admission characteristics were considered as potential predictors of mortality. Multivariate logistic regression was used to identify predictors of mortality with adjusted odds ratios (AOR) and 95% confidence intervals (CI) calculated. RESULTS There were 348 cases over the 8-year period. The mortality rate was 19%. Patients aged≥65 years were at higher odds of mortality (AOR 7.6, 95% CI: 2.8, 20.4) than patients aged 15-34 years. Patients hypotensive at the scene (AOR 5.5, 95% CI: 2.3, 13.2), and on arrival at the definitive hospital of care (AOR 3.7, 955 CI: 1.7, 8.0), were more likely to die than patients without hypotension. The presence of a severe chest injury was associated with an increased odds of mortality (AOR 2.8, 95% CI: 1.3, 6.1), whilst patients injured in intentional events were also more likely to die than patients involved in unintentional events (AOR 4.9, 95% CI: 1.6, 15.6). There was no association between the hospital of definitive management and mortality after adjustment for other variables, despite differences in the protocols for managing these patients at the major trauma services (Level 1 trauma centres). CONCLUSIONS The findings highlight the importance of effective control of haemodynamic instability for reducing the risk of mortality. As most patients survive these injuries, further research should focus on long term morbidity and the impact of different treatment approaches.

The imaging and classification of severe pelvic ring fractures: Experiences from two level 1 trauma centres

We describe the routine imaging practices of Level 1 trauma centres for patients with severe pelvic ring fractures, and the interobserver reliability of the classification systems of these fractures using plain radiographs and three-dimensional (3D) CT reconstructions. Clinical and imaging data for 187 adult patients (139 men and 48 women, mean age 43 years (15 to 101)) with a severe pelvic ring fracture managed at two Level 1 trauma centres between July 2007 and June 2010 were extracted. Three experienced orthopaedic surgeons classified the plain radiographs and 3D CT reconstruction images of 100 patients using the Tile/AO and Young-Burgess systems. Reliability was compared using kappa statistics. A total of 115 patients (62%) had plain radiographs as well as two-dimensional (2D) CT and 3D CT reconstructions, 52 patients (28%) had plain films only, 12 (6.4%) had 2D and 3D CT reconstructions images only, and eight patients (4.3%) had no available images. The plain radiograph was limited to an anteroposterior pelvic view. Patients without imaging, or only plain films, were more severely injured. A total of 72 patients (39%) were imaged with a pelvic binder in situ. Interobserver reliability for the Tile/AO (Kappa 0.10 to 0.17) and Young-Burgess (Kappa 0.09 to 0.21) was low, and insufficient for clinical and research purposes. Severe pelvic ring fractures are difficult to classify due to their complexity, the increasing use of early treatment such as with pelvic binders, and the absence of imaging altogether in important patient sub-groups, such as those who die early of their injuries.

Review of techniques for monitoring the healing fracture of bones for implementation in an internally fixated pelvis

Sacral fractures from high-impact trauma often cause instability in the pelvic ring structure. Treatment is by internal fixation which clamps the fractured edges together to promote healing. Healing could take up to 12 weeks whereby patients are bedridden to avoid hindrances to the fracture from movement or weight bearing activities. Immobility can lead to muscle degradation and longer periods of rehabilitation. The ability to determine the time at which the fracture is stable enough to allow partial weight-bearing is important to reduce hospitalisation time. This review looks into different techniques used for monitoring the fracture healing of bones which could lead to possible methods for in situ and non-invasive assessment of healing fracture in a fixated pelvis. Traditional techniques being used include radiology and CT scans but were found to be unreliable at times and very subjective in addition to being non in situ. Strain gauges have proven to be very effective for accurate assessment of fracture healing as well as stability for long bones with external fixators but may not be suitable for an internally fixated pelvis. Ultrasound provides in situ monitoring of stiffness recovery but only assesses local fracture sites close to the skin surface and has only been tested on long bones. Vibration analysis can detect non-uniform healing due to its assessment of the overall structure but may suffer from low signal-to-noise ratio due to damping. Impedance techniques have been used to assess properties of non-long bones but recent studies have only been conducted on non-biological materials and more research needs to be done before it can be applicable for monitoring healing in the fixated pelvis.

Functional and return to work outcomes following major trauma involving severe pelvic ring fracture

There is limited evidence describing the long‐term outcomes of severe pelvic ring fractures. The aim of this study was to describe the longer term independent living and return to work outcomes following severe pelvic ring fracture.

Delaying urinary catheter insertion in the reception and resuscitation of blunt multitrauma and using a full bladder to tamponade pelvic bleeding

This article proposes a counter-argument to standard Advanced Trauma Life Support (ATLS) training--which advocates bladder catheterisation to be performed as an adjunct to the primary survey and resuscitation for early decompression of the bladder and urine output monitoring. We argue the case for delaying bladder catheterisation until after definitive truncal Computed Tomography (CT) imaging. To reduce pelvic volume and associated bleeding, our trauma team delay catheter insertion until after the initial CT scan. The benefits of a full bladder also include improved views on initial Focussed Assessment with Sonography in Trauma (FAST) scan and improved interpretation of injuries on CT. Our urinary catheter related infection rates anecdotally decreased when insertion was delayed and consequently performed in a more controlled, non-resuscitation setting following CT. Adult blunt multitrauma patients with pelvic ring fractures are at risk of significant haemorrhage. Venous, arterial and medullary injuries with associated bleeding may be potentiated by an increased pelvic volume with ring disruption, as well as a reduced pressure effect from retroperitoneal and intra-pelvic organs on bleeding sites. Various techniques are used to reduce intra-pelvic bleeding. For shocked patients who have sustained major pelvic injuries with no other signs of urinary tract trauma and minimal urine in the bladder on initial FAST scan, we advocate careful, aseptic Foley catheter insertion followed by bladder insufflation with 500-600 mL of Normal Saline (NS) and subsequent catheter clamping to tamponade pelvic bleeding.

Experimental Testing of Vibration Analysis Methods to Monitor Recovery of Stiffness of a Fixated Synthetic Pelvis: A Preliminary Study

Monitoring the healing of long bones has been studied extensively to reduce the period of encumbrance and unnecessary pain for patients suffering from fractured bones. This is more critical for unstable fractures in the pelvis as the patients can bedridden for up to 12 weeks to allow proper healing to take place. Current methods employed to monitor long bone healing are insufficient for applications in the pelvis as the human pelvis presents a significant change in geometry which demands a different approach. This paper explores an approach where vibration analysis is used to provide in-situ monitoring of a healing fracture in a human pelvis. Experimental tests were conducted on 4th generation synthetic pelvises instrumented with an array of PZT sensors. The synthetic pelvises were cut at the sacrum to simulate a fractured pelvis followed by the application of araldite epoxy to simulate healing by allowing the epoxy to cure. Measurements were collected from the sensor array over the curing period to obtain the transfer functions (TFs) for various excitations. An impact hammer was utilised to obtain powerful broadband excitations while the PZT sensors were used to detect the response in the synthetic pelvis as a results of these excitation signals. A comparison of TF against cure time (healed amount) indicates the presence of a significant relationship with the stiffness recovery of the epoxy at the cut of the synthetic model.

Structural health monitoring: An orthopaedic perspective

Having unstable sacral fractures requires patients to be bedridden for a significant period of time for healing to take place without complications. This causes severe muscle atrophy, along with blood circulation problems in older patients. It is therefore highly beneficial to fast-track weight-bearing activities to reduce these complications by monitoring the recovery of the fracture. Past experimental work shows that dynamic response of a fixated synthetic (fourth-generation composite sawbone) pelvis is affected by the change in stiffness at the fracture location. The changes in this dynamic response can be observed by placing sensors on the pelvis and on the fixation. However, placing sensors on the pelvis is not practical. The aim of this article is to report on a set of computational investigation on the potential of placing sensors on the fixation to determine the stiffness restoration of the fractured region of the pelvis. This work will focus on the Denis I fracture, where the fracture is located in the sacrum. The ability to relate the dynamic response of a particular section of the fixation that is remote to the fracture location will have significant implication in the extending structural health monitoring concept to determine the state of healing of a fractured pelvis. A fourth-generation composite sawbone pelvis was used in the work reported in this article.

Numerical Simulation of Vibrational Methods for the Healing Assessment of an Internally Fixated Femur

Current bone healing monitoring techniques (X-ray, CT, manual manipulation) are subjective and qualitative. A quantitative monitoring technique for an internally fixated femur based on vibrational techniques is investigated. An intramedullary (IM) nail fixated femur will be at the focus of the investigation. The femur and fixation were modelled and their structural dynamics were solved using finite element analysis. This allowed visualisation of various mode shapes and identification of those most sensitive to healing. It was found that torsional modes were most sensitive to the stiffness change associated with healing. This data was then used as a guide for the placement of simulated accelerometer sensors and the simulated excitation point to predict the cross spectrum data that would be obtained during an experiment. Upon analysis of this data the torsional mode suggests that a relationship can be drawn between the natural frequency of the torsion mode and the state of health

Pelvic trauma mortality reduced by integrated trauma care

A multidisciplinary approach that emphasised improved triage, early pelvic binder application, early administration of blood and blood products, adherence to algorithmic pathways, screening with focused sonography (FAST), early computed tomography scanning with contrast angiography, angio‐embolisation and early operative intervention by specialist pelvic surgeons was implemented in the last decade to improve outcomes after pelvic trauma. The manuscript evaluated the effect of this multi‐faceted change over a 12‐year period.

Healing Assessment of Fractured Femur: Orthopaedic SHM

Bone fractures are fixated to facilitate healing. The fixations used are broadly classified as internal and external fixation. External fixations are often used as a temporary means to stabilise the fracture prior to the application of the internal fixation. However, in the case of injuries suffered during combat, external fixations have been reported to be used as definitive treatments. When fixated, the healing process of the fractured region can take several months depending on the extent of the fracture. The ability to ascertain union at the fracture region is crucial to the patient’s return to normal duties. The assessment techniques available include X-ray and CTscans. This paper presents a set of findings to demonstrate the utilisation of the construction of an external fixation to integrate structural health monitoring concepts to facilitate the establishment of the state of union of a fractured femur. The paper will firstly provide a brief review of healing and union of fractured bones, the types of fixation used and the current methods of assessing healing and bone union. A set of experimental results will be presented to demonstrate the potential of integrating structural health monitoring concept in the overall clinical management of fractures. doi: 10.12783/SHM2015/178