Transcript 下載/瀏覽Download

Prediction of Enophthalmos by ComputerBased 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
1
Outline
Introduction
Problems and Rationale
Purpose
Materials and Methods
Results
Discussions
Conclusions
Future works
Reference
2
Introduction
Problems and Rationale
3
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
4
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
Diplopia: 複視
Ocular motility limitation: 眼睛的能動性限制
Orbital emphysema: 眼窩氣腫
5
Problems and Rationale (3/7)
 Recognized sequelae of orbital blow-out
fracture include:
 Diplopia
 Enophthalmos
sequelae: 後遺症
6
Problems and Rationale (4/7)
Diplopia (Double vision)
 Pathology
 Two images of a
single object
 Displace
 Horizontally
 Vertically
 Diagonally
1. Monocular diplopia
2. Binocular diplopia
Monocular diplopia: 單眼複視
Binocular diplopia: 雙眼複視
Diagram of Diplopia
From:http://www.clinico.com.tw/eye1/
eye12/eye126/I126l.htm
7
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
8
Problems and Rationale (6/7)
Medial wall
The most common fracture sites:
Orbital floor
Medial wall
Orbital floor
An assessment of the fracture in the orbit and
the ethmoidal sinus:
CT
Clinical findings
9
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
10
Introduction
Purpose
11
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
12
Purpose (2/2)
Using computer-based measurement
Enophthalmos
Volume of an orbital wall fracture
It may be beneficial in predicting indications
for surgery.
13
Materials and Methods
14
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
15
Materials and Methods (2/6)
 In 35 patients
Medial wall
 25 patients
 A fracture in the medial wall of the orbit
 2 patients
 A fracture in the inferior wall
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
16
Materials and Methods (3/6)
mm3
Vol = A x 3 mm
Unit: mm3
3 mm:
Section thickness
Measurement of the fracture area and volume (A–F)
17
Materials and Methods (4/6)
Statistical analysis
 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
18
Materials and Methods (5/6)
Experimental cycle of Ophthalmic
examination:
 First day
 One week
 One month
 Three months later
19
Materials and Methods (6/6)
 Examination:
1.
2.
3.
4.
5.
6.
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
Pupillary reflex: 瞳孔反射
Extraocular motility: 眼外能動性
Hertel ophthalmometry: 赫特爾突眼計
20
Results
21
Results (1/7)
The patient's gender classification
Men: 28 of 35 patients
Women: 7 of 35 patients
The patient‘s age classification
Mean age: 37.06 years
Less than 50 years: 31 of 35 patients
22
Results (2/7)
Age and gender distribution
23
Results (3/7)
0 - 1.0 (ml)
54.3%
Fracture volume and enophthalmos
24
Results (4/7)
25
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.
26
Results (6/7)
Volume of the orbital fracture
Less than 1 ml  0.91 mm
2 ml  1.74 mm
Depth of enophthalmos
2 mm  2.30 ml
0.84 mm for every 1.0 ml increase in volume
27
Results (7/7)
Amount of late enophthalmos predicted from the fracture volume
Enophthalmos of 2 mm or more was predicted
with an orbital fracture volume of 2.30 ml.
28
Discussions
29
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.
30
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 on orbital
fracture patients without surgical treatment.
31
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%.
32
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
33
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.
34
Conclusions
35
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.
36
Future works
37
Future works (1/1)
Proof of orbital symmetry
Find out the relevant parameters
Increase the number of sample
Statistical verification
38
Reference
39
Reference (1/1)
 Ahn HB, et. al. Prediction of Enophthalmos by ComputerBased 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.ht
m
 From:http://blog.udn.com/jnwu/2937626
40
Thank you for your attention
41