Introduction Of A Novel Method Of Quantifying Post-operative Edema After Orbital Surgery
Irene A. Chang, B.A., Michael Wells, B.Eng, M.Eng., Edward H. Davidson, M.D., Anand R. Kumar, M.D..
Case Western Reserve University, Cleveland, OH, USA.
Title: Introduction of a Novel Method of Quantifying Post-Operative Edema After Orbital Surgery
Keywords: Edema, customized implant, traditional implant, orbit
Authors: Irene A. Chang, BA, Michael Wells, M.Eng, Anand R. Kumar, MD, Edward H. Davidson, MD
Postoperative orbital edema following orbital floor fracture repair is a refractory appearance-related stigma of injury and is associated with persistent diplopia, causes difficulty assessing globe position, and if prolonged, can lead to lid retractor strain and ptosis or malposition. Standardized approaches of edema quantification are lacking and therefore prognostication of symptom resolution and outcome prediction remains a challenge. This study aims to establish a novel quantifiable method for post-operative edema assessment.
Three dimensional photography was performed on patients undergoing orbital floor fracture repair. Images of each patient were taken pre-operatively and twice post-operatively (at 18-21 days and 29-42 days) and analyzed using the VECTRA imaging software. Preoperative images were superimposed on the first and second postoperative images based on anatomical facial landmarks around the orbit. The region of interest was defined by the area bordered within the lateral canthus, radix, subnasal, and intersection of lateral canthus and subnasal. The total volume, maximum distance, and surface area in the selected region were measured for the superimposed images of each patient and correlated with globe projection, reported diplopia and palpebral opening. The Pearson's correlation coefficient was then calculated to determine significant correlations.
The mean of the difference in volume and surface area in the first post-operative (P1) and second post-operative (P2) visit was 1.21 cc and -0.52 mm2, and 1.42 cc and 1.63 mm2, respectively. The mean palpebral opening in the unaffected eye was 11.50 mm, 11.95 mm, and 14.11 mm for the pre-operative visit, P1, and P2, respectively, and in the affected eye was 10.85 mm, 11.04 mm, and 11.31 mm pre-operatively, P1, and P2, respectively. The p-values between the unaffected and affected eye for palpebral opening were 0.50, 0.069, and 0.078 for pre-operative visit, P1, and P2, respectively. The mean global projection in the affected eye was 15.22 mm, 16.36 mm, and 15.36 mm pre-operatively, P1, and P2, respectively. The mean global projection in the unaffected eye was 17.35 mm, 15.79 mm, and 17.06 mm pre-operatively, P1, and P2, respectively. The p-values between the unaffected and affected eye for global projection were 0.069, 0.62, and 0.11 for pre-operative visit, P1, and P2, respectively.
The palpebral opening and globe projection were measured as a difference between the unaffected and affected side in each patient in order to control for variance. Statistically significant correlations were found between both the change in volume (r=0.63, p=0.025) as well as the surface area (r=0.921, p<0.001) in regards to the globe projection. However, these
differences in surface area and volume were not statistically correlated with the palpebral opening. Occurence of diplopia was also noted in each of the patients.
A standardized quantifiable method for post-operative edema assessment can be a helpful tool to predict final outcome of globe position, diplopia resolution and lid position.
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