Evaluation of a computed-tomography-based assessment scheme in treatment decision-making for isolated orbital floor fractures

Orbital fractures treated in a university hospital of southern Italy: epidemiology, outcomes and prognostic factors resulting from 538 retrospectively analyzed cases

PURPOSE

Orbital fractures are common injuries and represent an interesting chapter in maxillofacial surgery. This retrospective study analyses data collected from 528 patients surgically treated at the University Hospital "Magna Graecia", Catanzaro, Italy, from 1st January 2007 to 31st January 2021.

METHODS

The inclusion criteria were a diagnosis of orbital bone fracture, complete clinical and radiological records, and a minimum follow-up of 12 months. We analyzed gender, age, etiology, fracture type, treatment, timing of repair, and associated complications.

RESULTS

The most frequent cause of trauma was road accidents (37.88%), followed by domestic accidents (25.95%). The manifestation of diplopia (72.35%), infraorbital nerve hypoesthesia (53.41%), extrinsic eye movement limitation (51.70%), and enophthalmos (41.29%), determined the indication for surgery. Our trauma team preferred the sub-eyelid approach (79.36%). The study shows a statistical significance in the correlation between the severity of the herniation of the lower rectus muscle and the presence of preoperative diplopia (p-value = 0.00416); We found the same statistical significance for the post-postoperative diplopia (p-value = 0.00385). Patients treated two weeks after the trauma show a higher rate of diplopia and a greater limitation of long-term post-operative eye movements than those treated within two weeks (diplopia 23.08% vs. 15.56%; eye movements limitation 13.33% vs. 7.69%). Early surgical treatment (> 14 days) reduces the likelihood of functional and structural damage to the lower rectus muscle.

CONCLUSION

Our data will support future maxillofacial traumatology studies, and the education and prevention measures taken will reduce the incidence of orbital trauma.

Reflections on a patient-centered approach to treatment of blow-out fractures: Why the wisdom of the pastmust guide our decision-making

The management of blow-out orbital fractures (BOFs) continues to be controversial and regularly questioned. In recent years, treatment decision-making has shifted from a clinically dominated emphasis to a more objective data-based approach. This has come about through the refinement of imaging technologies that can more precisely define the fracture itself. Decision-making is now mainly driven by computed tomography (CT) parameters among which the fracture's size is by far the most often used. The variability in a patient's clinical presentation and outcomes for similar types of BOFs raises serious doubts about the pertinence of applying standardized guidelines based on quantitative data for the treatment of individual patients. An approach that fails to include patient variability and relies too heavily on average objective results with an emphasis on the application of quantitative rather than qualitative methods can lead to poor patient outcomes. A review of the knowledge accumulated over the many years of treatment of BOFs has demonstrated that despite the exceptional imaging-based technologies available, clinical acumen remains the most sophisticated decision-assistive tool. Thus, the treatment of BOFs must be regarded as a patient rather than merely a geometrical imaging issue. Imaging then becomes a valuable diagnostic rather than a final decision-making tool. This more conservative approach leads to a substantial decrease in indications for surgical repair.

CT parameters in pure orbital wall fractures and their relevance in the choice of treatment and patient outcome: a systematic review

Computed tomography (CT) is commonly used for the diagnosis, treatment planning, and prognosis of pure orbital fractures of the orbital floor and medial wall. The aim of this study was to systematically review the current literature in order to establish an overview of CT parameters relevant to the choice of treatment and (long-term) clinical outcome for patients treated operatively and conservatively. The PRISMA guidelines were followed. Databases were searched using the terms 'orbital fracture' and 'computed tomography'. Studies evaluating the relationship between CT parameters and the treatment decision or clinical outcome (enophthalmos, diplopia, and/or limitation of ocular movement) were included. The search yielded 4448 results of which 31 were included (except for three, all were retrospective). The systematic use of CT imaging in orbital fractures of the floor and the medial wall can be of great value in the treatment decision and prediction of (long-term) clinical outcomes for both conservatively and surgically treated patients. The following parameters were found to be the most relevant: fracture size, fracture location, orbital volume, soft tissue involvement, and craniocaudal dimension. Although some show great individual potential, it is likely that incorporating all parameters into an algorithm will provide the best predictive power and thus would be the most practically applicable tool.

Virtual reconstruction of orbital floor defects using a statistical shape model

PURPOSE

The current standard in reconstructing defects of the orbital floor, by using the concept of mirroring, is time-consuming and ignores the natural asymmetry of the skull. By using a statistical shape model (SSM), the reconstruction can be automatized and improved in accuracy. The present study aims to show the possibilities of the virtual reconstruction of artificial defects of the orbital floor using an SSM and its potentials for clinical implementation.

METHODS

Based on 131 unaffected CT scans of the midface, an SSM was created which contained the shape variability of the orbital floor. Nineteen midface CT scans, that were not included in the SSM, were manually segmented to establish ground truth (control group). Then artificial defects of larger and smaller sizes were created and reconstructed using SSM (Group I) and the gold standard of mirroring (Group II). Eventually, a comparison to the surface of the manual segmentation (control group) was performed.

RESULTS

The proposed method of reconstruction using an SSM leads to more precise reconstruction results, compared with the conventional method of mirroring. Whereas mirroring led to the reconstruction errors of 0.7 mm for small defects and 0.73 mm for large defects, reconstruction using SSM led to deviations of 0.26 mm (small defect) and, respectively, 0.34 mm (large defect).

CONCLUSIONS

The presented approach is an effective and accurate method for reconstructing the orbital floor. In connection with modern computer-aided design and manufacturing, individual patient-specific implants could be produced according to SSM-based reconstructions and could replace current methods using manual bending techniques. By acknowledging the natural asymmetry of the human skull, the SSM-based approach achieves higher accuracy in reconstructing injured orbits.

Prediction of surface area size in orbital floor and medial orbital wall fractures based on topographical subregions

OBJECTIVE

This retrospective study evaluates the occurrence and frequency of different fracture patterns in a series of computed tomography (CT) scans in terms of the AOCMF Trauma Classification (TC) orbit module and correlates the assigned defects with measurements of the fracture area in order to get an approximate guideline for fracture size predictions on the basis of the classification.

MATERIAL AND METHODS

CT scans of patients with orbital floor fractures were evaluated using the AOCMFTC to determine the topographical subregions. The coding consisted of: W = orbital wall, 1 = anterior orbit, 2 = midorbit, i = inferior, m = medial. The 3-dimensional surface area size of the fractures was quantified by the "defect body" method (Brainlab, Munich, Germany). The fracture area size and its confidence and prediction interval within each topographical subregion was estimated by regression analysis.

RESULTS

A total of 137 CT scans exhibited 145 orbital floor fractures, which were combined with 34 medial orbital wall fractures in 31 patients. The floor fractures - W1(i)2(i) (n = 86) and W1(i) (n = 19) were the most frequent patterns. Combined floor and medial wall fractures most frequently corresponded to the pattern W1 (im)2 (im) (n = 15) ahead of W1 (im) 2(i) (n = 10). The surface area size ranged from 0.11 cm² to 6.09 cm² for orbital floor and from 0.29 cm² to 5.43 cm² for medial wall fractures. The prediction values of the mean fracture area size within the subregions were computed as follows: W1(i) = 2.25 cm², W2(i) = 1.64 cm², W1(i)2(i) = 3.10 cm², W1(m) = 1.36 cm², W2(m) = 1.65 cm², W1(m)2(m) = 2.98 cm², W1 (im) = 3.35 cm², W1 (im) 2(i) = 4.63 cm², W1 (im)2(m) = 4.06 cm² and W1 (im)2 (im) = 7.16 cm².

CONCLUSION

The AOCMFTC orbital module offers a suitable framework for topographical allocation of fracture patterns inside the infero-medial orbital cavity. The involvement of the subregions is of predictive value providing estimations of the mean 3-D fracture area size.

Association Between Compensatory Overaction of the Non-Injured Eye, Measured by HESS Chart and Postoperative Diplopia in Blow-Out Fracture

In orbital floor fracture, diplopia often persists post-operatively. This study evaluated the association between pre-operative parameters concerning the extent of the injury and post-operative diplopia, using multivariate analysis. A retrospective computed tomography analysis and chart review was performed for patients with punched out orbital floor fracture, who underwent operations during the period from April 2011 to March 2018. Five parameters were evaluated: the number of upward arrows on the Hess chart (representing compensatory overaction of the non-injured eye), time interval to surgery, muscular subscores, fracture area, and swelling rate of the inferior rectus muscle. Of the 32 patients, 9 (28%) had post-operative diplopia; pre-operative diplopia was completely restored in 23 (72%) patients by 6 months after surgery. Univariate analysis found statistically significant differences in the number of upward arrows on the Hess chart, time interval to surgery, muscular subscores, and fracture area. Logistic regression analysis demonstrated that only the number of upward arrows displayed a significantly increased risk for post-operative diplopia (odds ratio, 15.3; 95% confidence interval, 2.0-117.0; P = 0.008). Excessive overaction of the non-injured eye predicted persistent diplopia by 6 months post-operatively. Surgical intervention may be insufficient to achieve full recovery from diplopia and disturbances of ocular motility in some patients.

Validation of the "Wisconsin Criteria" for Obtaining Dedicated Facial Imaging and Its Financial Impact at a Level 1 Trauma Center

Introduction

According to national trauma databases, 25% of all people injured have some type of facial injury. The gold standard for diagnosing bony trauma of the facial skeleton has been computed tomography (CT) scan. In 2011, the "Wisconsin criteria" were established and subsequently validated as a method to predict which patients truly have a facial fracture and warrant further imaging. The purpose of this study is to externally validate these criteria and determine the economic impact they might have on avoiding unnecessary CT scans.

Methods

This was a retrospective chart review. We collected 1000 patients who had undergone facial CT related to trauma and retrospectively applied the "Wisconsin criteria" based on physical exam documentation.

Results

Of the 1000 facial CT scans obtained, we identified 408 fractures, 12% of which required operative intervention. The "Wisconsin criteria" applied to our patient population had a sensitivity of 90% and a negative predictive value of 93%. Using these criteria resulted in a missed fracture rate of 2.8%. Finally, had these criteria been used to determine when a facial CT scan was indicated, our institution could be saving over US$300 000 annually.

Conclusion

The "Wisconsin criteria" are a reliable method to screen for facial fracture in trauma patients. Using a validated instrument tool to guide decision-making, we can avoid obtaining low-value imaging studies. This can have a large economic impact while maintaining safety and reliability in accurate diagnosis.