Ahn HB, et. al. Ophthalmic Plastic and Reconstructive Surgery. 2008 ； 24 ： 36–9.

1. Prediction of Enophthalmos by Computer-Based Volume Measurement of Orbital Fractures in a Korean Population Ahn HB, et. al. Ophthalmic Plastic and Reconstructive Surgery. 2008；24：36–9. Presenter: Che-Hao Chuang Professor: Dr. Yen-Ting Chen Date: 2009/12/08

2. Outline • Introduction • Problems and Rationale • Purpose • Materials and Methods • Results • Discussions • Conclusions • Future works • Reference

3. Introduction • Problems and Rationale

4. Problems and Rationale (1/7) • Orbital blow-out fractures are frequent due to popularity of motorcycle traffic accident. Orbital blow-out fracture: 眼窩骨折

5. Problems and Rationale (2/7) An orbital fracture due to trauma can induce complications: • Enophthalmos • Ocular motility limitation • Diplopia • Orbital emphysema • Injury to the inferior orbital nerve • Vision loss Enophthalmos:眼球內陷Ocular motility limitation: 眼睛的能動性限制Diplopia:複視 Orbital emphysema: 眼窩氣腫

6. Problems and Rationale (3/7) • Recognized sequelae of orbital blow-out fracture include: • Diplopia • Enophthalmos sequelae:後遺症

7. Pathology Two images of a single object Displace Horizontally Vertically Diagonally Monocular diplopia Binocular diplopia Problems and Rationale (4/7) Diplopia (Double vision) Diagram of Diplopia From:http://www.clinico.com.tw/eye1/eye12/eye126/I126l.htm Monocular diplopia:單眼複視Binocular diplopia:雙眼複視

8. Problems and Rationale (5/7) Enophthalmos • Pathology: The displacement backward of eyeball • The difference of eyes retraction is more than 2mm (3 to 4mm or more). • Congenital: Primary enophthalmos • Facial asymmetry & Dysplasia • Postnatal: Secondary enophthalmos • Origin: caused by the reduction of orbital contents or increase of volume of orbit cavity From: http://blog.udn.com/jnwu/2937626

9. Problems and Rationale (6/7) Medial wall • The most common fracture sites: • Orbital floor • Medial wall • An assessment of the fracture in the orbit and the ethmoidal sinus: • CT • Clinical findings Orbital floor

10. Problems and Rationale (7/7) • The underlying cause of enophthalmos: • A discrepancy between the volume of the orbital soft tissue and the bony orbital cavity • Displacement of the orbital tissue from the bony orbit: • Entrapped tissue • Fat necrosis • Posterior soft-tissue fibrosis

11. Introduction • Purpose

12. Purpose (1/2) • Enophthalmos > 2.0 mm  Surgical intervention • During the acute posttrauma period • It is difficult to predict the degree of enophthalmos accurately. • It may be underestimated. • Orbital edema

13. Purpose (2/2) • Using computer-based measurement • Enophthalmos • Volume of an orbital wall fracture • It may be beneficial in predicting indications for surgery.

14. Materials and Methods

15. Materials and Methods (1/6) • Sample of research: • Thirty-five Korean patients with orbital blowout fractures who were not treated with surgery. • Exclude criteria: • Bilateral orbital wall fracture • Lateral wall and roof fracture • Inadequate CT • Age less than 18 years • Surgical repair of the fracture Lateral wall:外側壁

16. Materials and Methods (2/6) Medial wall • In 35 patients • 25 patients • A fracture in the medial wall of the orbit • 2 patients • A fracture in the inferior wall • 8 patients • A combined fracture in the medial wall and inferior wall • CT scanning system: • SOMATOM Sensation 16 • Image processing system • Rapidia: CT or MRI  3D image Inferior wall

17. Materials and Methods (3/6) Vol = A x 3 mm Unit: 3 mm: Section thickness Measurement of the fracture area and volume (A–F)

18. Pearson correlation coefficient (r) Consecutive correlation between two variables -1 ≦ r ≦ 1, r > 0, positive correlation r < 0, negative correlation r = 0, no correlation Fracture volume and late enophthalmos Linear regression analysis The relationship between Two consecutive variables The prediction of late enophthalmos Statistical software SPSS Materials and Methods (4/6) Statistical analysis

19. Materials and Methods (5/6) • Experimental cycle of Ophthalmic examination: • First day • One week • One month • Three months later

20. Materials and Methods (6/6) • Examination: • Visual acuity • Slit lamp examination • Pupillary reflex test • Goldmann diplopia test by perimetery • Extraocular motility measurement • Hertel ophthalmometry to measure enophthalmos Slit lamp:裂隙燈 Extraocular motility:眼外能動性 Pupillary reflex:瞳孔反射Hertel ophthalmometry:赫特爾突眼計

21. Results

22. Results (1/7) • The patient's gender classification • Men: 28 of 35 patients • Women: 7 of 35 patients • The patient‘s ageclassification • Mean age:37.06years • Less than 50 years: 31 of 35 patients

23. Results (2/7) Age and gender distribution

24. Results (3/7) 0 - 1.0 (ml) 54.3% Fracture volume and enophthalmos

25. Results (4/7)

26. Results (5/7) • Mathematical formula of linear regression analysis: E = enophthalmos (mm) V = fractured site volume (ml) SEE = standard error of estimate • It was used to calculate the expected degree of late enophthalmos.

27. Results (6/7) • Volume of the orbital fracture • Less than 1 ml 0.91 mm • 2 ml  1.74 mm • Depthof enophthalmos • 2 mm  2.30 ml • 0.84 mm for every 1.0 ml increase in volume

28. Results (7/7) Amount of late enophthalmos predicted fromthe fracture volume • Enophthalmos of 2 mm or more was predicted with an orbital fracture volume of 2.30 ml.

29. Discussions

30. Discussions (1/5) Why use CT? Many studies have mentioned E.X. Gilbard et al. Best means of observing the bone structure and soft tissues of the orbit. It’s great help in predicting the prognosis of a patient with a fracture in the orbital floor.

31. Discussions (2/5) • Interrelated studies • To predict enophthalmos after an orbital fracture, per ml increase in the orbital volume. • Raskin et al.  0.47 mm (per ml) • Whitehouse et al.  0.77 mm (per ml) • Ploder et al.  0.81 mm(per ml) • Fan et al.  0.89 mm (per ml) • However, less studies that focused onorbital fracture patients without surgical treatment.

32. Discussions (3/5) • Attentive item • Compared with the orbital volume of the normal eye • A tilted head positioning during CT scanning • Normally, the volume between the right and left orbit may differ by approximately 7% to 8%.

33. Discussions (4/5) In the present study • Measuring the volume of the orbital fracture site. • Source: the consecutive coronal CT • Rapidia software • 2D  3D • Area and volume

34. Discussions (5/5) Predicted benefits Decrease mistake Surgical repair is not always necessary in the treatment of orbital fractures. Underestimation of the amount of late enophthalmos It won’t delay with surgery.

35. Conclusions

36. Conclusions (1/1) • A significant correlation • The fracture site volume and the degree of late enophthalmos. • Predicting overall enophthalmos and provide useful information to surgeons.

37. Future works

38. Future works (1/1) • Proof of orbital symmetry • Find outthe relevant parameters • Increase the number of sample • Statistical verification

39. Reference

40. Reference (1/1) • Ahn HB, et. al. Prediction of Enophthalmos by Computer-Based Volume Measurement of Orbital Fractures in a Korean Population. Ophthalmic Plastic and Reconstructive Surgery. 2008；24：36–9. • From:http://www.clinico.com.tw/eye1/eye12/eye126/I126l.htm • From:http://blog.udn.com/jnwu/2937626

41. Thank you for your attention