Orbital anatomical parameters affecting outcome of deep lateral orbital wall decompression

Abstract

<jats:sec><jats:title>Purpose:</jats:title><jats:p> To determine orbital anatomical parameters that affect surgical outcome of deep lateral orbital wall decompression. </jats:p></jats:sec><jats:sec><jats:title>Methods:</jats:title><jats:p> Twenty orbits of 20 patients with moderate proptosis (maximum 25 mm) due to thyroid eye disease who were stable for at least 6 months were included in this prospective cohort study. Four parameters including lateral orbital wall distance (LOWD), removable surface area (RSA), removable surface length (RSL), and sphenoid door jamb thickness (SDJ) were evaluated by computed tomography (CT) scan prior to surgery in these patients. Deep lateral orbital wall decompression without fat removal was done in all patients. Relationship between all these factors and proptosis reduction, 6 months after surgery was assessed. </jats:p></jats:sec><jats:sec><jats:title>Results:</jats:title><jats:p> Mean proptosis before decompression surgery (mean ± SD) was 23.22 ± 1.19 mm and reduction in Hertel exophthalmometry (mean ± SD) was −3.27 ± 1.03 mm ( p = 0.006). Pearson correlation showed that LOWD, RSL, and SDJ had statistically significant correlation with proptosis reduction ( p = 0.017, 0.002, and 0.001, respectively.). Linear multivariate regression analysis showed SDJ as the only independent factor in predicting surgical outcome. </jats:p></jats:sec><jats:sec><jats:title>Conclusion:</jats:title><jats:p> several orbital anatomical factors have significant role in predicting surgical outcome following deep lateral wall orbital decompression. Among these parameters, SDJ is an independent factor, whereas LOWD and RSL are dependent factors. Preoperative assessment of the bony sphenoid anatomy may be helpful in predicting the amount of potential decompression. </jats:p></jats:sec>

3-D cephalometry of the the orbit regarding endocrine orbitopathy, exophthalmos, and sex

“…This was stressed by Shin et al [43] who investigated safe zones for decompression surgery in the lateral orbit in non-EO CT-scans, although their data on the sphenoid trigone cannot be compared with our findings due to different measurements. Furthermore, an analysis of anatomical parameters affecting the outcome of decompression surgery in EO showed that sphenoid trigone removal was an independent important factor [44]. Comparing EO to non-EO data, a statistically significant difference regarding the sphenoid trigone was seen in our study highlighting the importance of this structure.…”

“…As Borumandi et al pointed out in a review paper, sound anatomical knowledge is a prerequisite for surgical success in EO decompression surgery [91], and this study furnishes new anatomical data. The sphenoid trigone and its anterior-posterior dimensions seem to be of special importance as surgical parameters in decompression surgery discussed in Cruz et al 2021 [92] and described as an important surgical factor by Rajabi et al [44]. Furthermore, the data provided on orbital rim anatomy, especially supraorbital rim protrusion and lateral rim retrusion can be important in planning EO decompression surgery [15].…”

Orbital Decompression: Conceptual Approach for Orbital Volume Expansion

“…48 Alacrima has also been reported infrequently with superolateral orbital ab interno dissection. 49…”

“…Extensive removal of the bony wall overriding the temporalis muscle can result in oscillopsia. 49–51…”

“…48 Alacrima has also been reported infrequently with superolateral orbital ab interno dissection. 49 Lateral dissection in the temporal fossa can lead to temporalis wasting. 42 That may be a reason to avoid coronal or temporal approaches.…”