Magnetic Resonance Imaging in Pelvic Fractures – Part 2: Gaining Information and Clinical Therapeutic Relevance

Imaging of pelvic ring fractures in older adults and its clinical implications-a systematic review

Identifying the full scope of pelvic fracture patterns in older adults has gained clinical importance since the last decennium. CT is recommended as the golden standard; however, MRI has even greater diagnostic accuracy. Dual energy computed tomography (DECT) is a new and promising imaging technique, but the diagnostic accuracy in the context of pelvic fragility fractures (FFPs) has not been widely established. The aim was to provide insight into the diagnostic accuracy of different imaging techniques and the relevance for clinical practice. A systematic search was performed in the PubMed database. All studies that reported on CT, MRI or DECT imaging techniques in older adults who suffered a pelvic fracture were reviewed and, if relevant, included. Eight articles were included. In up to 54% of the patients, additional fractures were found on MRI compared to CT, and in up to 57% of the patients on DECT. The sensitivity of DECT for posterior pelvic fracture detection was similar to MRI. All patients without fractures on CT appeared to have posterior fractures on MRI. After additional MRI, 40% of the patients had a change of classification. DECT and MRI showed very similar results in terms of diagnostic accuracy. Over a third of all patients appear to have a more severe fracture classification after MRI, the majority changing to Rommens type 4. However, in only a few patients who changed of fracture classification, a change of therapy was advised. This review suggests that MRI and DECT scans are superior in diagnosing FFPs.

Insufficiency Fractures vs. Low-Energy Pelvic Ring Fractures - Epidemiological, Diagnostic and Therapeutic Characteristics of Fragility Fractures of the Pelvic Ring

BACKGROUND

Fragility fractures of the pelvis (FFP) encompass two fracture entities: fracture after low-energy trauma and insufficiency fracture without trauma. It is unclear whether the two subgroups differ in terms of diagnosis and therapy. The aim of this retrospective study was to evaluate insufficiency fractures with regard to defined parameters and to compare specific parameters with the fractures after low-energy trauma.

PATIENTS AND METHODS

In the period from 2008 to 2017, 203 patients with FFP were recorded at our clinic (Level 1 Trauma Centre DGU, SAV approval). Of these, 25 had an insufficiency fracture and 178 had a pelvic ring fracture after low-energy trauma. Epidemiological, diagnostic and therapeutic parameters were examined.

RESULTS

There was a relative increase in the insufficiency fracture within the FFP (2008 - 2009: 5.0% vs. 2015 - 2017: 17.8%). In these patients, osteoporosis tended to be more pronounced than in patients after low-energy trauma (t-value: - 3.66 vs. - 3.13). The diagnosis of insufficiency fractures showed increased use of MRI and DECT (60.9% vs. 26.0%) and a high proportion of type IV fractures after FFP (40.0% vs. 7.9%). In terms of therapy, surgical treatment of the insufficiency fracture was sought more often (68,2% vs. 52,1%), with a tendency towards increased use of combined osteosynthesis procedures (14.3% vs. 7.6%).

CONCLUSION

We were able to show that as the number of cases increases, the insufficiency fracture becomes more important within FFP. If these patients tend to have more pronounced osteoporosis, particular attention should be paid to the diagnosis and adequate therapy of the osteoporosis, especially in the case of an insufficiency fracture. In addition to the increased diagnostic testing using MRI and DECT to detect oedema and the increased surgical therapy for this type of fracture, it is also noteworthy that the insufficiency fracture can cause higher-grade fractures after FFP.

[Radiological diagnosis of pelvic ring fractures]

EPIDEMIOLOGY

Traumatic fractures of the pelvic ring are relatively rare, but are associated with increased risk of mortality. Depending on injury mechanism and main vector of energy impact, a distinction is made between anteroposterior compression, lateral compression, and vertical shear (Young and Burgess classification), while the stability-related classification according to Tile distinguishes between type A (stable), type B (rotationally unstable) and type C (completely unstable). A comprehensive modern classification is given by the AO/OTA.

RADIOLOGICAL FRACTURE DIAGNOSIS

Plain pelvis x‑rays lack sufficient sensitivity but are still used to detect highly unstable pelvic fractures. CT has superior sensitivity and specificity. In addition to fracture classification, CT allows reliable assessment of associated vascular and bladder/urethral injuries and large soft tissue hemorrhage. MRI is unparalleled in showing bone marrow edema, cauda and plexus complications, and peripelvic soft tissue damage. MRI may also prove to be a valuable diagnostic tool for pelvic ring injuries in children, adolescents and young women, provided they are hemodynamically stable. Angiography, ultrasonography and bone scintigraphy are additional important diagnostic and therapeutic options.

PRACTICAL RECOMMENDATIONS

Knowledge of basic pelvic trauma mechanisms is important to understand the potential severity of traumatic pelvic fractures and to classify them correctly in terms of stability. Being familiar with typical concomitant injuries in pelvic ring fractures allows reliable diagnosis and their communication with the clinician. CT remains the "diagnostic workhorse". In fragile pelvic fractures, the often prolonged course with fracture progression must be taken into account, which is why MRI is of particular importance herein.

Fragility Fractures of the Pelvic Ring – Does the Evidence of Oedema Lead us to More Surgeries?

Introduction The choice of therapy for fragility fractures of the pelvis (FFP) is largely determined by the diagnosed fracture morphology. It is now unclear whether the change in diagnostic options – sensitive detection of fracture oedema in the sacrum using MRI and dual-energy computed tomography (DECT) – has an impact on the therapeutic consequences. The aim of this retrospective study was therefore to evaluate the change in the diagnostics used and the resulting therapy regimen in our patient population.

Materials and Methods We performed a monocentric-retrospective analysis of 196 patients with a fragility fracture of the pelvis in our clinic (national TraumaZentrum® DGU and SAV approval) in the period from 2008 to 2017. We examined changes in epidemiology, diagnostics/classification and therapy of the pelvic ring fractures treated by us.

Results The diagnostic procedures used are subject to a clear change towards oedema detection using MRI and DECT. The graduation has changed towards more severe forms of fracture after FFP. There is now also an increasing proportion of patients treated by surgery (2008 – 2009: 5.3% vs. 2015 – 2017: 60.3%).

Conclusion We were able to show that the introduction of sensitive diagnostic procedures coincided with a higher classification of the fractures. It is also noteworthy that the increase in operations is not only due to a higher degree of classification; also in relative terms, more patients are operated on within type FFP II.

Magnetic Resonance Imaging in Pelvic Fractures – Part 1: Which Criteria Lead Us to Supplementary MRI Diagnostics?

Introduction Isolated pelvic fractures are relatively rare with an incidence of 3 – 6% of all fractures, but their incidence in polytraumatized individuals increases to 25%. The S3 guideline Polytrauma gives a clear recommendation for diagnostics by means of pelvic radiography (X-ray) and computed tomography (CT). A recommendation for the diagnosis by means of magnetic resonance tomography (MRI) especially in patients with low energetic/missing trauma does not currently exist. It is unclear on the basis of which criteria the MRI can be indicated in pelvic fractures. The aim of our study was therefore to retrospectively record indications for the indication of MRI in pelvic fractures – with adequate as well as inadequate trauma.

Material and Methods In a retrospective clinical study, a total of 140 patients (median 68 years, range 15 – 97, 75 female, and 66 male) with a pelvic fracture were included in the study over a period of three years. Overall, the trauma mechanism revealed 73 adequate and 67 inadequate fractures. 31/140 patients had undergone MRI of the pelvis in addition to a CT/X-ray scan. The two subgroups “with MRI” and “without MRI” were analyzed with regard to the parameters “sex”, “age”, “adequacy of the trauma”, “fracture localization”, “duration of admission to imaging”, “type of therapy” and “duration to surgery” compared.

Results It was shown that the MRI diagnosis was performed especially in female, elderly patients (81 years, range 19 – 94 years). Patients with inappropriate trauma have received MRI more frequently (74%) than patients with adequate trauma (26%). With regard to fracture localization no differences could be shown. The MRI was performed on a median 4 days after the CT examination. Regarding the decision “conservative” vs. “operationally” our two groups without and with MRT tended to differ not. Patients with MRI were operated on median 2 days later than patients who did not receive MRI.

Conclusions Pelvic fracture MRI should be performed primarily in elderly female patients without adequate trauma. In patients with adequate trauma, MRI is of low value, especially as MRI diagnostics are performed with delay, resulting in later surgery.