HSC Section 3 - Trauma, Critical Care and Sleep Medicine

G. Frohwitter et al. / Journal of Cranio-Maxillo-Facial Surgery 46 (2018) 1550 e 1554

radiological factor in the treatment decision-making process for IOFF ( Schouman et al., 2012 ). Other studies suggest defect sizes of more than 1 cm 2 and more than 50% of the entire orbital fl oor as being primary radiological indicators for surgical intervention ( Burnstine, 2003; Cole et al., 2007, Parbhu et al., 2008 ). Moreover, other CT fi ndings, such as the degree of fracture displacement and the herniation of peri-orbital soft tissues into the maxillary sinus, are included in surgical decision making ( Tahernia et al., 2009 ). Jaquiery et al. have developed a descriptive fi ve-stage classi fi cation of orbital wall defects based on CT scans in axial and coronal sections, and on a two-dimensional orbital sketch ( Jaquiery et al., 2007 ). Categories I e V are classi fi ed depending on the size of the defect, the localisation of the defect, and the involvement of distinct anatomical landmarks. However, the de fi nition of cate- gories is still arbitrary. Accurate, objective algorithms for decision making remain absent from the current literature. Decisions on whether a surgical approach should be chosen rather than a conservative treatment regime often depend on eminence-based factors that lack dependable guidelines and a reliable algorithm. Taking all the described parameters from other researchers into consideration, we have developed an easy-to-adapt assess- ment scheme, as displayed in detail in Table 1 . Categories I to IV describe the extent of an IOFF based on (i) fracture size, (ii) incarceration of soft tissues, (iii) displacement of the inferior rectus muscle (IRM), (iv) presence of periorbital emphysema, and (v) presence of intraorbital bone fragments. Fig. 1 shows exam- ples of the categories described above. Nevertheless, this is a simpli fi ed assessment scheme, because the anatomical structures within in the orbit and all the adjacent landmarks are extremely complex. Furthermore, we have evaluated the CT-based assessment scale for IOFF and correlated the radiological fi ndings with preoperative clinical parameters. Surgeons engaged in the complex care of patients with orbital fractures require step-by- step guidelines that facilitate decision making and enable the identi fi cation of individuals in need of surgical reconstruction of bony orbital buttresses. Our approach is aimed at meeting this need. This retrospective study followed the Declaration of Helsinki on medical protocol and ethics. The Regional Ethical Review Board of the Technical University of Munich (TUM), Germany approved the study (No. 547/16 S). The medical records of the TUM Department of Oral and Maxillofacial Surgery, between January 2011 and December 2015, were analysed, and all patients with unilateral isolated orbital fl oor fractures (IOFF) were identi fi ed. All patients who met the following inclusion criteria were included in the current study: (i) preoper- ative CT scans in all three sections; availability for analysis of (ii) a preoperative and (iii) a postoperative ophthalmological examination. Table 1 Categorisation of isolated orbital fl oor fractures (IOFF) using a CT-based assessment scheme. Fracture size (cm 2 ) Incarceration of ST 2. Materials and methods 2.1. Patients

2.2. Ophthalmological examination

All patients were assessed by an ophthalmologist. Depending on the patient's compliance, an ophthalmological examination was performed preoperatively and after surgical intervention. Impaired vision, presence of diplopia, ex- or enophthalmos, eyeball motility, and any other ophthalmological injuries were documented.

2.3. Assessment of computed tomography (CT) scans

Imaging was performed with a 64-slice CT scanner. The cate- gorisation of IOFF was based on the following radiomorphological criteria ( Table 1 ): (i) size of the IOFF, measured in cm 2 from sagittal and coronal sections; (ii) displacement of the orbital fl oor, in mil- limetres; (iii) displacement of the inferior rectus muscle (IRM) ( Schouman et al., 2012 ); (iv) change in the diameter of the IRM of the fractured orbital fl oor compared with the healthy contralateral side, as an indirect indicator for ophthalmological symptoms; (v) volume of soft tissue herniated into the maxillary sinus; (vi) incarceration of periorbital soft tissues; (vi) presence of intraorbital emphysema; (vii) presence of intraorbital bone fragments; and (viii) whether the infraorbital nerve (ION) was affected. All frac- tures were divided into four categories, as described in detail above. IBM SPSS version 24.0 (IBM, Armonk, NY, USA) was used. For univariate analysis, the Mann e Whitney U test, unpaired two- sample t -test, and Fisher's exact test were performed. For multi- variate analysis, a linear regression analysis was performed as a multiple approach. Stepwise forward and backward variable se- lection approaches were applied to account for potential multi- collinearity. Receiver operating characteristic (ROC) analysis was carried out and ROC curves were created to show the diagnostic value of respective outcome measures. All p values are given as two-sided and are subject to a local signi fi cance level of 5%. In total, 106 patients were enrolled into this study: 66 (62.3%) were male and 39 (36.8%) female. Causes of trauma included as- sault ( n ¼ 42; 39.6%), domestic accidents ( n ¼ 41; 38.7%), sport accidents ( n ¼ 18; 17%), and road traf fi c accidents ( n ¼ 5; 4.7%). Correlation between trauma mechanism and gender was statis- tically signi fi cant ( p < 0.001; Fisher's exact test), as more male pa- tientswere affected byassault ( n ¼ 37; 56.9% vs n ¼ 3; 7.7%) and sport accidents ( n ¼ 12; 18.5% vs n ¼ 6; 15.4%); whereas more females suffered from domestic accidents ( n ¼ 27; 69.2% vs n ¼ 14; 21.5%). In terms of CT-morphological parameters and their correlation with preoperative ophthalmological symptoms, the size of the fracture seemed to be signi fi cantly associated with the presence of diplopia ( p ¼ 0.014, unpaired two-sample t -test; Fig. 2 ). However, no further statistically signi fi cant correlation with the following ophthalmological symptoms could be shown (all unpaired two- sample t -tests): decreased mobility ( p ¼ 0.794), retro-orbital 2.4. Statistical analysis 3. Results

Displacement of IRM

Emphysema

Bone fragments

I

< 2 > 2 > 2 > 2

No No

1 1

No No

No No

II

III IV

Yes Yes

Yes

Yes Yes

Yes Yes

> 3

Abbreviations: CT ¼ computed tomography; ST ¼ soft tissue; IRM ¼ inferior rectus muscle.

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