Die hämodynamisch wirksame Beckeninstabilität

Evaluating the stability of external fixators following pelvic injury: A systematic review of biomechanical testing methods

INTRODUCTION

This systematic review aims to identify previously used techniques in biomechanics to assess pelvic instability following pelvic injury, focusing on external fixation constructs.

METHODS

A systematic literature search was conducted to include biomechanical studies and to exclude clinical trials.

RESULTS

Of an initial 4666 studies found, 38 met the inclusion criteria. 84% of the included studies were retrieved from PubMed, Scopus, and Web of Science. The studies analysed 106 postmortem specimens, 154 synthetic bones, and 103 computational models. Most specimens were male (97% synthetic, 70% postmortem specimens). Both the type of injury and the classification system employed varied across studies. About 82% of the injuries assessed were of type C. Two different fixators were tested for FFPII and type A injury, five for type B injury, and fifteen for type C injury. Large variability was observed for external fixation constructs concerning device type and configuration, pin size, and geometry. Biomechanical studies deployed various methods to assess injury displacement, deformation, stiffness, and motion. Thereby, loading protocols differed and inconsistent definitions of failure were determined. Measurement techniques applied in biomechanical test setups included strain gauges, force transducers, and motion tracking techniques.

DISCUSSION AND CONCLUSION

An ideal fixation method should be safe, stable, non-obstructive, and have low complication rates. Although biomechanical testing should ensure that the load applied during testing is representative of a physiological load, a high degree of variability was found in the current literature in both the loading and measurement equipment. The lack of a standardised test design for fixation constructs in pelvic injuries across the studies challenges comparisons between them. When interpreting the results of biomechanical studies, it seems crucial to consider the limitations in cross-study comparability, with implications on their applicability to the clinical setting.

Effect of C-Clamp Application on Hemodynamic Instability in Polytrauma Victims with Pelvic Fracture

Background and Objectives: C-clamp application may reduce mortality in patients with unstable pelvic fractures and hemodynamic instability. Decreasing C-clamp use over the past decades may have resulted from concerns about its effectiveness and safety. The purpose of this study was to document effective hemodynamic stabilization after C-clamp application by means of vital parameters (primary outcome parameter), and the subsequent effect on metabolic indices and volume management (secondary outcome parameters). Materials and Methods: C-clamp application was performed between 2014 and 2021 for n = 13 patients (50 ± 18 years) with unstable pelvic fractures and hemodynamic instability. Vital parameters, metabolic indices, volume management, and the correlation of factors and potential changes were analyzed. Results: After C-clamp application, increases were measured in systolic blood pressure (+15 mmHg; p = 0.0284) and mean arterial pressure (+12 mmHg; p = 0.0157), and a reduction of volume requirements (p = 0.0266) and bolus vasoactive medication needs (p = 0.0081) were observed. The earlier C-clamp application was performed, the greater the effect (p < 0.05; r > 0.6). Heart rate, shock index, and end-tidal CO2 were not significantly altered. The extent of base deficit, hemoglobin, and lactate did not correlate with changes in vital parameters. Conclusions: In the majority of hemodynamically unstable trauma patients not responding to initial fluid resuscitation and severe pelvic fracture, early C-clamp application had an additive effect on hemodynamic stabilization and reduction in volume substitution. Based on these findings, there is still a rationale for considering early C-clamp stabilization in this group of severely injured patients.

[Influence of external pelvic stabilization on hemodynamically unstable pelvic fractures]

BACKGROUND

In the treatment of complex pelvic fractures hemorrhage control is of primary importance; however, studies regarding the localization of bleeding are contradictory so that various treatment approaches are recommended. The primary aim of external pelvic compression applied in the trauma room is to reduce the pelvic volume and counteract blood loss through self-induced tamponade. This study examined the influence of external pelvic compression on mortality and outcome in cases of hemodynamically unstable pelvic fractures in a larger number of cases.

MATERIAL AND METHODS

The current study used the TraumaRegister DGU® (TR-DGU) to retrospectively evaluate the records of 104 patients treated between 2002 and 2011. All patients suffered severe injury with an injury severity score (ISS) of at least 16 points. In addition, the patients were hemodynamically unstable with confirmed relevant isolated pelvic injuries. To evaluate the effectiveness of external pelvic compression, patients with and without external pelvic stabilization were compared.

RESULTS

Of the investigated patients 26.9 % died of their injuries and of these the mortality was 78.6 % within the first 6 h of admission to the trauma room. External pelvic stabilization was performed in 45.2 % of patients. The mortality was 19.1 % in patients with external pelvic stabilization and in contrast, the mortality in the group of patients without external pelvic stabilization was 33.3 %. During the course of hospitalization, surviving patients with external pelvic stabilization were significantly more likely to develop sepsis or multiple organ failure and required longer periods of intensive care.

CONCLUSION

External pelvic stabilization seems to be an important instrument for the initial treatment of hemodynamically unstable pelvic fractures and showed a positive effect on patient mortality.

Biomechanical analysis of a transiliac internal fixator

PURPOSE

We evaluated the biomechanical characteristics of the transiliac internal fixator (TIFI) as compared to two well-established methods of internal posterior pelvic ring fixation.

METHODS

Six freshly frozen human pelves were used for simulated single-leg stance loading of an AO type C injury model (pubic symphysis diastasis and unilateral sacroiliac joint disruption). The symphysis rupture was stabilized with a dynamic compression plate. Afterwards the three internal stabilization systems (TIFI, iliosacral screws and ventral plate osteosynthesis) were analysed. Fragment movement was measured in a contact-free manner with a stereophotometric infrared system.

RESULTS

No significant differences in the three-dimensional deformation tolerated by the TIFI as compared to the other internal fixation systems were found.

CONCLUSIONS

The transiliac internal fixator provides the same biomechanical stability as the other reference implants tested. We suggest the use of this device as a suitable alternative to the other implants.

[Treatment of polytrauma in the intensive care unit]

The treatment of severely injured trauma patients (polytrauma) is one of the outstanding challenges in medical care. Early in the initial course the patient's diagnostics have to be scrupulously reevaluated by an interdisciplinary team (tertiary trauma survey) to reduce deleterious sequelae of missed injuries after the initial assessment. Severely injured patients stay in intensive care for an average of 11 days. During this time the patient's therapy has to ensure a high quality evidence-based intensive care treatment and simultaneously has to be tailored to the current individual injuries. Because of the fact that the damage control strategy is gaining increasing acceptance, the intensive care unit plays a pivotal role in the critical time between emergency and elective surgery. Therefore a close cooperation between physicians of the intensive care unit and all surgical disciplines involved is essential to reach the aim of therapeutic efforts. After survival of emergency treatment patients with severe trauma should be reintegrated into social and occupational life as soon as possible.

Anwendung der Beckenzwinge beim polytraumatisierten Patienten mit instabilem Becken

BACKGROUND

Unstable fractures of the posterior pelvic ring are frequently combined with severe hemorrhage. In 80% of cases the bleeding originates in the ruptured presacral venous plexus or the fracture itself. Arterial bleeding is less common. The pelvic clamp introduced by Ganz can make it possible to stabilise the pelvis, with subsequent compression of the fracture planes and reduction of the intrapelvic volume in such cases, so improving the prognosis. Use of the pelvic clamp can be integrated into the management in the emergency room with no problem.

METHODS

This paper presents the authors' own modification of the technique for using the pelvic clamp in the emergency situation when only a clinical examination of the patient has been possible and also analyses specific problems that arise in this situation. To this end, the data relating to 29 polytraumatised patients with unstable posterior pelvic ring fractures were analysed in a retrospective study.

RESULTS

In all, 8 complications were seen in 6 patients. There were 2 cases of pin malposition and 2 of over-compression of the ossa coxae and local wound problems. Secondary pin dislocation was observed in 1 case. In all these cases it was possible to correct the pelvic clamp, so that emergency stabilisation was practicable without further surgical intervention. Minor complications were found in 2 patients. These took the form of bleeding at the pin-insertion site. In 1 case an unstable transiliacal fracture was found, and in this case it was not possible to stabilise the posterior pelvic ring with the pelvic clamp. No iatrogenic lesions were detected following application of the pelvic clamp.

CONCLUSION

In the hands of an experienced and practised user application of the pelvic clamp is a safe method for emergency stabilisation of the posterior pelvic ring in polytraumatised patients, even without blood volume control. Problems can be solved and do not generally mean the pelvic clamp cannot be used. The immediate radiological check (e.g. during the emergency CT -scan performed for primary diagnosis) is a must, however.

Stumpfe Beckenverletzung

Life-threatening complex pelvic fractures are commonly associated with vast peripelvine soft-tissue injuries and hemorrhage. Correct assessment and classification of the existing pelvic trauma and additional severe injuries present is required for accurate diagnosis and effective therapy. Treatment of the usually multiply injured patient is time-sensitive. The circulatory situation is the benchmark for diagnostic and therapeutic actions. Emergency stabilization of an initially unstable pelvic ring should be done first, followed by an extraperitoneal tamponade, if needed to control bleeding. The positive results of these actions can be measured by hemodynamic parameters. Delayed definitive internal stabilization of the anterior and/or posterior pelvic ring is then performed according to the fracture classification.

Operative Versorgungsstrategien beim Polytrauma mit Beckenfraktur

OBJECTIVE

In the management of multiply injured patients the question of the optimal time point for surgical treatment of individual injuries still remains open. Especially in severely injured patients with pelvic fractures, this decision differs between rapid surgical interventions in life-threatening situations or time-consuming reconstructive surgery. Besides the "early" operative treatment, i.e., within the first 24 h after trauma, the "late," i.e., definitive or secondary surgical fracture stabilization, exists. The following study represents a review of the current recommendations in the literature concerning the optimal time and fracture management of multiply injured patients with pelvic fracture.

METHODS

Clinical trials were systematically collected (MEDLINE, Cochrane, and hand searches), reviewed, and classified into evidence levels (1 to 5 according to the Oxford system).

RESULTS

According to the literature there is consensus on "early" operative stabilization of multiply injured patients with hemodynamically and mechanically unstable pelvic fractures, open pelvic fractures, or complex pelvic trauma. External fixation and the pelvic C-clamp are the methods of choice in emergency situations, whereas currently internal fracture fixation is only proposed in exceptional circumstances. In contrast, the point in time for the secondary definitive fracture stabilization remains controversially discussed. This discussion ranges from the postulation that extensive definitive fracture treatment be avoided during days 2-4 after trauma to the recommendation that definitive internal fixation of pelvic fractures be undertaken early, i.e., within the 1st week after trauma.

CONCLUSION

Basically, the principles of trauma management of multiply injured patients with life-threatening hemorrhage from mechanically unstable pelvic fractures are divided into two main time periods. On the one hand, there is the emergency stabilization of the pelvic ring as the most important goal within the acute period to control the bleeding, at least with extraperitoneal tamponade if necessary. On the other hand, once the hemorrhaging has been stopped, the "late" and definitive internal fracture stabilization of the pelvis should be performed depending on the fracture pattern.