Orbital imaging

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ORBITAL
IMAGING


F. Allan Midyett, MD, DABR
Neuroradiologist
Department of Radiology
Howard University Hospital
Washington, D.C.

Suresh K. Mukherji, MD, MBA, FACR
Professor and Chairman
Walter F. Patenge Endowed Chair
Department of Radiology
Michigan State University
East Lansing, Michigan

1600 John F. Kennedy Blvd.
Ste 1800
Philadelphia, PA 19103-2899
ORBITAL IMAGING

ISBN: 978-0-323-34037-3

Copyright © 2015 by Saunders, an imprint of Elsevier Inc.
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This book and the individual contributions contained in it are protected under copyright by the Publisher
(other than as may be noted herein).

Notices
Knowledge and best practice in this field are constantly changing. As new research and experience
broaden our understanding, changes in research methods, professional practices, or medical treatment
may become necessary.
Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using any information, methods, compounds, or experiments described herein. In using such
information or methods they should be mindful of their own safety and the safety of others, including
parties for whom they have a professional responsibility.
With respect to any drug or pharmaceutical products identified, readers are advised to check the
most current information provided (i) on procedures featured or (ii) by the manufacturer of each
product to be administered, to verify the recommended dose or formula, the method and duration
of administration, and contraindications. It is the responsibility of practitioners, relying on their own
experience and knowledge of their patients, to make diagnoses, to determine dosages and the best

treatment for each individual patient, and to take all appropriate safety precautions.
To the fullest extent of the law, neither the Publisher nor the authors, contributors, or editors, assume
any liability for any injury and/or damage to persons or property as a matter of products liability,
negligence or otherwise, or from any use or operation of any methods, products, instructions, or ideas
contained in the material herein.
Library of Congress Cataloging-in-Publication Data
Midyett, F. Allan, author.
Orbital imaging / F. Allan Midyett, Suresh K. Mukherji.
p. ; cm.
Includes bibliographical references and index.
ISBN 978-0-323-34037-3 (pbk. : alk. paper)
I. Mukherji, Suresh K., author. II. Title.
[DNLM: 1. Orbital Diseases—diagnosis. 2. Diagnostic Imaging. 3. Orbit—injuries. WW 202]
RE711
617.7’807572—dc23
2014038261

Content Strategist: Helene T. Caprari
Content Development Specialist: Amy Meros
Publishing Services Manager: Catherine Jackson
Senior Project Manager: Carol O’Connell
Design Direction: Brian Salisbury

Printed in the United States of America
Last digit is the print number:  9  8  7  6  5  4  3  2  1


First, this book is dedicated to my children, Scott,
Laura, and Brian, who probably never
understood why I spent so much time on radiology.

Then, to my parents, who were convinced that
all those years of education and training would
eventually bear fruit.
Then, to all those patients with cancer who will
probably never understand the important role
radiologists and ophthalmologists play in early
diagnosis and proper treatment of their very
personal disease.
Then, to my faithful friends Cooper and Vana
(the Vizslas) who unequivocally never
understand why I waste “valuable” time sitting
at the computer when I could be playing with them.
And last but not least, to my darling wife
Diane, who always understands each and every
day how very how much this book means to me.


Preface
Orbital Imaging was created to serve as a handy
reference and learning text. It was meant to
answer questions created by that “funny eye
case” and to whet the reader’s appetite for more.
It was envisioned as a book that the reader could
start in the airport and read all the way through
or start in middle and read a single chapter. Or
better yet, read all the way through during the
flight and then come back to relook at a certain
chapter when the reader encounters that unusual
orbital case.
I wanted to present pertinent orbital pathologies that included those entities we see every day,

those entities we see mostly on board examinations, and some entities that are rare as hen’s
teeth but some say we are “supposed to know”
when we see them.
I wanted to give the reader a complete,
although “thumbnail,” sketch in a format that
hopefully could be easily remembered. I wanted
to package the individual components in a logical fashion so that the reader could first and
foremost quickly find the section he or she is
looking for. But even more important I wanted
the reader to be able to quickly identify the section not wanted to be reviewed at any particular
time.
I wanted to depict those images that best
demonstrated the pathologic entity with the best
imaging sequences. Some of these cases are truly
“rare birds,” and we brought you the best images
we had available. But imagine the esthesioneuroblastoma, an entity that has only been reported
1000 times since it was first described in 1924 by
Berger and Luc. We had five cases to choose
from, and we show four in this text.

iv

As my interest in correlation between radiologic imaging and gross pathology runs long and
deep, I couldn’t resist the opportunity to share a
few gross pathology images with the reader, in
the hope that this correlation cements the image
in your psyche.
The orbit has a rich and long history dating
back hundreds and even thousands of years. The
subsection “Historic Highlights” hopefully will

be one that will be of interest to many when
making a casual read through. When the book is
used as a quick reference for that eye case that
has to be discussed with the clinician right now,
this is one of the first sections to skip.
The differential section has been written
with great care. I have tried to find contrasting
findings to help you tell the difference, if these
points can be found. Sure, some of these are
really “Aunt Minnies” and if they are, we say so.
But some of these differentials are really tough,
and I believe this section is potentially helpful,
imparting wisdom usually found from our
prized professors. Well, we did get a lot of it
from them.
But most of all, I wanted to make this textbook one that readers would enjoy reading and
find that certain sections just stuck in their
minds. Yes, in some ways this text takes a simplistic approach. You will find the statistics and
the nomenclature have been rounded off. To the
big book purists, I apologize. To those of you
who seek the sleeker approach, I do hope you
learn something, find something to remember,
and enjoy reading it!
F. Allan Midyett, MD


Acknowledgments
As I look back on a long and exciting career in
radiology, I always remember first and foremost
the impressive radiology showman David S.

Carroll, who caused me to say “Wow, I can’t
believe he can read all that from the radiograph!” And then I just had to go into radiology.
Then I learned that Dr. Carroll really was a
great radiologist, but he was a fantastic showman! While Dr. Carroll’s list of accomplishments was longer than this acknowledgement, it
was his showmanship that caused me and others
to go into radiology. And then I settled down to
learn under the watchful tutelage of C. Allen
Good. No one ever accused Dr. Good of being a
showman, just as no one doubted he was an exceptional radiologist. Dr. Good set superb standards for the practice of radiology both at the
Mayo Clinic and for the entire country during
his more than a quarter century leading the
American Board of Radiology as its president
and secretary.
My mentors are TNTC (Too Numerous to
Count). Many, like Bob Scanlon, Dave Reese,
Colin Holman, Hillier L. “Bud” Baker, and others, have relocated and are currently watching
over us from on high.

And to top all this, I had the fabulous opportunity to do my neuroradiology fellowship with
Mauricio Castillo and Suresh Mukherji, and I
caught a glimpse of academic neuroradiology
like I never saw it before. Their level of expertise
blew my mind, and in the process I developed a
love for head and neck radiology, and specifically
orbital imaging.
Suresh Mukherji has been an incredible mentor for me in my fellowship, and has proven to
be an invaluable co-author of Orbital Imaging.
I would like to thank the fabulous folks at
Elsevier, including (but not limited to) Helene
Caprari, Amy Meros, Kathryn DeFrancesco, and

Carol O’Connell.
And while my almost half century in radiology has taught me that we can’t all be like Dave
Carroll and dazzle people all the time, I will
submit that these are some of my most memorable moments in radiology. I do hope you enjoy
the book and go out and dazzle someone sometime with what you have learned from Orbital
Imaging.
F. Allan Midyett, MD

v


CONTENTS

•

PART I

TRAUMA AND SURGERY
1

MEDIAL B LOWOUT FRACTURE,

3

2

BLOWOUT ORBITAL FLOOR FRACTURE,

3

ORBITAL ExENT ERAT 10 . ,

4

ORBITAL FLOOR MESH,

5

ANTERIOR CHAMBER P ERFORATION,

6

OCULAR LENS DISPLACEMENT,

7

R UPTURED GLOBE,

8

PHTHISIS BULBI,

9

O CULAR PROSTHESIS,

9

14

76

19

R£TIN OBLASTOMA,

20

ORBITAL L EUKEMI A,

21

OPTIC NERVE METASTASIS,

87

22

E sTHESIONEUROBLASTOMA,

91

23

RHA8DOMYOSARCOMA,

•

PART IV

80

99

18

20

CONGENITAL

23

26
29

CoLOBOMA,

25

P ERSIST ENT H YPERPLASTIC PRIMARY
VITREO US,

32

10

R ETINAL DETAC HMENT ,

•

PART II

35

BENIGN TUMORS

112

26

CONGENITAL ORBITAL TERAT0.\1.A,

27

CONGENITAL A.N OPHTHALMIA,

•

PART V

116

121

VASCULAR

11

ORBITAL CAVERl ous HEMANG IOMA,

12

OPTIC NERVE GLIOMA,

13

OPTIC

14

POSTERIOR ORBITAL DERMOIDS,

15

ORBITAL LIPOMA,

16

ORBITAL SCHWAN OM A,

44

TERVE MENI NG IOMA,

105

24

48
54

41

28

CAROTID-CAVERNOUS FISTULA,

29

CAVERNOUS SINUS TH ROMBOSIS,

30

ORBITAL VEN OUS VA RIX,

31

VE ous L YMPHATIC M ALFORMATION,

•

PART VI

127
133

139
143

57

59

DEGENERATIVE
•

PART III

32

PosTERIOR O cuLAR STAPHYLOMA,

MALIGNANT TUMORS

33

CATARACTS: B EFORE AND AFTER,

65

34

OPTIC Di sc DRUSEN,

17

O CULAR AnNEXAL L YM PHOM A,

18

OcuLARMELANOMA,

vi

71

156

149
153


CONTENTS

•

PART VII

•

MUSCLE CONE

INFLAMMATORY

35

GRAVES 0RBITOPATHY,

36

IDJOPATHIC ORBITAL PsEUDOTUMOR,

•

PART X

161
166

207

44

ORBITAL ABSCESS,

45

CYTOMEGALOVIRUS RETINITIS,

46

PoTT's PuFFv T uMoR,

•

PART XI

211

215

PART VIII

OPTIC PATHWAY
37

OPTIC NERVE

EURITIS,

175

UNCERTAIN ETIOLOGY

38

OPTIC NERVE LEUKEMIA,

178

47

PswDoTUMOR CEREBRJ,

48

WEGENER GRA1 U LOMATOSlS,

•

PART XII

•

PART IX

LACRIMAL GLAND
39

LACRIMAL GLAND SARCOIDOSIS,

40

LACRIMAL GLAND L YM PHOMA,

185
188

BONY ORBIT
49

ORB ITAL PLASMACYTOMA AND
MYELOMA,

41

LACRIMAL GLAND DERMOID,

42

ADENOID CYSTIC CARCINOMA

19 1

50
OF THE LACRIMAL GLAND,

43

223

194

SQUAMOUS CELL CARCINOMA
OF THE LACRIMAL SAC,

200

233

FrnRous DvsP LASIA,
ABBREVIATIONS

247

241

22 7

Vii

PA RT I

TRAUMA AND
SURGERY
PART OUTLINE
1 Medial Blowout Fracture

3

2 Blowout Orbital Floor
Fracture

9

3 Orbital Exenteration

14

4 Orbital Floor Mesh

18

5 Anterior Chamber Perforation 20
6 Ocular Lens Displacement

23

7 Ruptured Globe

26

8 Phthisis Bulbi

29

9 Ocular Prosthesis

32

10 Retinal Detachment

35

1



CHAPTER 1

Medial Blowout Fracture
KEY POINTS
• Definition: Medial blowout fractures
(MBOFs) result from direct trauma to the
orbit transmitting most of the force to the
globe. This causes the orbital contents
to “blow out” through the path of least
resistance, usually the paper-thin lamina
papyracea or orbital floor.
• Classic clue: Bowing or displacement

of the medial orbital wall in a patient
with known or presumed facial trauma
and soft tissue density in the adjacent
ethmoid sinus. Some patients show
enophthalmos, restrictive strabismus, or
infraorbital numbness.
• Trauma to the orbit may be isolated
or may be part of a more generalized
traumatic episode.
• Patients who present with orbital trauma
may not give a clear trauma history, either
because of posttraumatic neurologic
sequelae or because of something they
ingested or imbibed previously.
• MBOFs may initially appear to be the
least of the patient’s problems and may
be overlooked by the trauma team,
including the radiology resident/fellow.
• Many patients with MBOFs have old
or new fractures and occasionally a
combination of both, which the radiologist
needs to deal with.

IMAGING
• Computed tomography (CT) is the first line
of imaging in patients with orbital trauma.
• It may be necessary to add CT of the face
and/or orbits to the imaging protocol if
only brain CT is requested.

Computed Tomography Features
• Medial bowing or displacement of the medial
orbital wall.
• Fracture may be visible through the bony
cortex with or without displacement.

• Bowing of the medial orbital wall may be so
smooth that it appears developmental, particularly if the fracture is old.
•New fractures usually have associated
findings with soft tissue density extending into the ethmoid sinus and adjacent
structures.
• Air collections may be visible within the
orbit and/or air-fluid levels.
• Multiplanar imaging is helpful with axial, coronal, and sagittal views. Three-dimensional
imaging is helpful and popular with clinicians.
• Fractures may be bilateral. Bilateral fractures
are unlikely to both be new and are more
likely to comprise an old and a new fracture.
Bilateral old fractures are often overlooked.

Magnetic Resonance
Imaging Features
• Magnetic resonance imaging is not usually
used for this entity.
• Bone detail is less clearly demonstrated
than by CT.

CLINICAL ISSUES
Presentation
• Most patients present to the emergency

department with a history of known trauma
to the face or orbit or with a history of suspected trauma to the head and face but are
“not really sure” what happened.
• Most fractures are secondary to personal
altercations. More complex fractures are
more likely to be related to motor vehicle
accidents and falls.1
• Associated clinical findings may include:
• Enophthalmos
• Diplopia
• Orbital emphysema
• Paresthesia secondary to damage of the
inferior orbital nerve

Natural History
• Given the currently common methods of
inner city conflict resolution, the prevalence
3


4

PART I  Trauma and Surgery

of blowout orbital fractures (BOFs) appears
to be inversely proportional to that of gunshot wounds (GSWs): as GSWs increase,
BOFs decrease and vice versa.
• A patient with a BOF is likely to come from
a population that includes several patients
with BOFs.

• Other facial fractures are also likely to be
common within such a population, including other types of BOFs.
• Around 50% of patients with blowout floor
fracture (BOFFs) were found to have
MBOFs.2
• The male:female ratio for MBOFs is 5:1.
• The left orbit is more frequently involved
because most attackers are right-handed.
• Fracture types include the following:
• Type I: Medial orbital wall only
• Type II: Medial orbital wall and continuous with the floor
• Type III: Medial orbital wall with floormalar fractures
• Type IV: Medial orbital wall and complex
midfacial injuries1
• Types I and II are best explained by hydraulic
theory, while Types III and IV are best
explained by bucking.

Treatment
• Most cases require no special treatment.
• Patients are usually told to not blow their
nose in an attempt to avoid forcing air and
bacteria into the orbit. However, it is not
clear how well patients follow this advice.
• When an acute fracture is recognized, the
patient may be given antibiotics to prevent
spread of the infection into the orbit.
• Surgery is only considered for complications.

Surgery

• Medial rectus entrapment requires early
diagnosis and treatment because reduced
blood flow and nerve compression may
cause permanent injury.3,4
• Current management favors early surgical
intervention in cases with frank extraocular
muscle entrapment.4,5
• Early intervention has been reported to
resolve diplopia in all entrapment cases.6

Complications
Infection
• See Chapter 44: Orbital Abscess, and
Chapter 29: Cavernous Sinus Thrombosis.

Entrapment and Ocular Motility
Impairment
• Motility disturbance results from damage
to or entrapment of the medial rectus muscle with consequent limitation of adduction
or abduction.
Enophthalmos
• May be the result of muscle atrophy caused
by entrapment, fat necrosis, contracture, or
prolapsed orbital contents.7
• Uncommon in isolated MBOFs.
• Twice as common in combined MBOF and
BOFF.1

PATHOLOGY
Hydraulic Theory

• Fracture caused by increased intraocular
pressure.

Buckling Theory
• Direct transmission of force proceeds
through the orbital bones.

Protective Process
• A BOF usually protects the most important
occupants of the orbit, the globe and optic
nerve, analogous to the situation in car
crashes when the folding fender disperses
the energy of the crash.

Current Consensus
• It is likely that a combination of hydraulic
and buckling forces is responsible.

A CLOSER LOOK
• Application of external force to the orbit by
a larger object causes compression and retropulsion of the orbital contents.
• Transmission of the resultant elevated intraorbital pressure may fracture the thin
floor and/or the paper-thin medial wall.
• Because of its paper-thinness (approximately
0.25 mm), the medial wall was named the
lamina papyracea (Latin for “layer of paper”).
Logic suggests that this layer would be fractured more often than the unsupported floor,
which is approximately 0.5 mm thick.

1  Medial Blowout Fracture

• Conventional wisdom conversely holds that
fractures of the orbital floor are more frequent
than fractures of the lamina papyracea. However, data from a large sample from a large inner city university suggest otherwise, indicating that the number of MBOFs far exceeded
the number of BOFFs. There was a strong
tendency for MBOFs to be initially missed by
busy radiologists concerned with more immediate issues such as GSWs and stroke. It is
also possible that the features of orbital trauma
differ among cities, but this is unlikely.
• Some authors have reported that, among
pure BOFs, isolated medial wall fractures
account for nearly 55% of orbital fractures.8
• It has been hypothesized that certain ethnic
groups may be anatomically predisposed to
medial wall fractures.9-11
• Ethmoid air cell septa support the lamina
papyracea. MBOFs occur in patients with
fewer ethmoid air cell septa (see Figure 1-4).12
• Most of the data in this chapter are derived
from cases involving African Americans and
may thus only reflect this specific population. However, other authors9-11 have raised
the question of an ethnic bias, and this possibility should be considered.

Historical Highlights
• Mackenzie investigated and described orbital
floor fractures in Paris in 1844.13
• Smith and Regan coined the term blow-out
fracture in 1957.14

A

REFERENCES
1. Brannan PA, Kersten RC, Kulwin DR: Isolated medial
orbital wall fractures with medial rectus muscle incarceration, Ophthal Plast Reconstr Surg 22:178–183, 2006.
2. Converse JM: On the treatment of blow out fractures
of the orbit, Plast Reconstr Surg 62:100–104, 1978.
3. Nolasco FP, Mathog RH: Medial orbital wall fractures:
classification and clinical profile, Otolaryngol Head Neck
Surg 112:549–556, 1995.
4. Zilkha A: Computed tomography of blow-out fracture 
of the medial orbital wall, AJR Am J Roentgenol 137(5):
963–965, 1981.
5. Jordan DR, Allen LH, White J, et al: Intervention within
days for some orbital floor fractures: the white-eyed
blowout, Ophthal Plast Reconstr Surg 14:379–390, 1998.
6. Bansagi ZC, Meyer DR: Internal orbital fractures in
the pediatric age group: characterization and management, Ophthalmology 107:829–836, 2000.
7. Egbert JE, May K, Kersten RC, et al: Pediatric orbital
floor fractures: direct extraocular muscle involvement,
Ophthalmology 107:1875–1879, 2000.
8. Ng P, Chu C, Young N, et al: Imaging of orbital floor
fractures, Australas Radiol 40(3):264–268, 1996.
9. Smith B, Regan WF: Blowout fracture of the orbit:
mechanism and correction of internal orbital fracture,
Adv Ophthalmic Plast Reconstr Surg 6:197–205, 1987.
10. Burm JS, Chung CH, Oh SJ: Pure orbital blowout
fracture: new concepts and importance of medial 
orbital blowout fracture, Plast Reconstr Surg 103:
1839–1849, 1999.

11. Gittinger JW, Hughes JP, Suran EL: Medial orbital
wall blow-out fracture producing an acquired retraction
syndrome, J Clin Neuroophthalmol 6:153–156, 1986.
12. Merle H, Gerard M, Raynaud M: Isolated medial orbital
blow-out fracture with medial rectus entrapment, Acta
Ophthalmol Scand 76:378–379, 1998.
13. Thiagarajah C, Kersten RC: Medial wall fracture: an update, Craniomaxillofac Trauma Reconstr 2(3):135–139, 2009.
14. Song WK, Lew H, Yoon JS, et al: Role of medial orbital wall morphologic properties in orbital blow-out
fractures, Invest Ophthalmol Vis Sci 50(2):495–499, 2009.

C

B

D

5

E

FIGURE 1-1  n ​A and B, Coronal orbital computed tomography (CT) showing dehiscent medial wall with orbital fat
herniating inferiorly and medially. Air-fluid level right frontal sinus. C, Axial CT showing large medial blowout
fracture on the right with orbital fat contiguous with blown-out component. D, Sagittal CT near midline depicting
large, extruded collection of intraorbital fat within the nasal cavity. E, Orbital plain film showing asymmetric
soft tissue density adjacent to the inferior medial aspect of the right orbit with loss of adjacent orbital margin,
corresponding with abnormality on CT images. Indicates superiority of CT imaging over plain films.


6

A

D

PART I  Trauma and Surgery

C

B

F

E

FIGURE 1-2  n  A and B, Axial computed tomography (CT) showing small “trap door” fracture through right lamina
papyracea with fatty tissue extruding into the adjacent ethmoid air cells. No entrapment of adjacent medial rectus
muscle. Air bubble extends into right orbit anteromedially. C and D, Coronal orbital CT demonstrating dehiscent
medial wall with orbital fat and fluid herniating inferiorly and medially, filling concha bullosa. E, Coronal orbital
CT confirming intraorbital air bubble location medially. F, Sagittal orbital CT showing location of small orbital wall
fragments posterior to conspicuous intraorbital air bubble.

A

B

FIGURE 1-3  n  A and B, Axial and coronal CT showing small medial blowout fracture involving the right orbit. Dehiscent lamina papyracea with herniated orbital fat. Medial rectus partially deviated into blowout but not trapped.

A

B

FIGURE 1-4  n  A, Recent medial blowout fracture (MBOF) showing medial deviation of the lamina papyracea
with soft tissue density blood and mucus in the ethmoid sinus. Soft tissue swelling present in the anterior orbit.
B, Recent MBOF with soft tissue in adjacent ethmoid air cells. Conspicuous hyperaerated ethmoid air cells with
relatively few septa. Predisposition to MBOF? See discussion regarding reference 7.


1  Medial Blowout Fracture

A

B

C

D

7

FIGURE 1-5  n  A and B, Medium medial blowout fractures (MBOFs) on left. C and D, Medium MBOFs on right. There
are no intraorbital air or sinus changes to suggest any of these MBOFs are recent.

A

B

FIGURE 1-6  n  A, Axial computed tomography (CT) showing small medial blowout fracture (MBOF) on left with
nothing to suggest recent injury. B, Coronal CT demonstrating small MBOF in upper portion of the right orbit with
dehiscent lamina papyracea permitting fat to herniate into an ethmoid sinus air cell.

8

PART I  Trauma and Surgery

C

B

A

D

E

FIGURE 1-7  n  Representative sample from multiple patients with old, bilateral medial blowout fractures, none of
which show any signs to suggest they are recent.


CHAPTER 2

Blowout Orbital Floor

Fracture
KEY POINTS
• Definition:Blowoutorbitalfloorfractures
(BOFFs)resultfromdirecttraumato
theorbittransmittingforcetotheglobe.
Thiscausestheorbitalcontentsto“blow
out”throughthepathofleastresistance,

usuallythepaper-thinlaminapapyraceaor
theorbitalfloor.
• Synonym:Internalorbitalfracture.
• Classicclue:Bowingordisplacement
oftheinferiororbitalwallinapatient
withknownorpresumedfacialtrauma
andsofttissuedensityintheadjacent
maxillarysinus.Somepatientsshow
enophthalmos,restrictivestrabismus,or
infraorbitalnumbness.
• Blowoutorbitalfractures(BOFs)may
involvetheorbitalfloor,medialorbital
wall,orrarelytheorbitalroof,while
sparingtheorbitalrim.
• Therearetwogenerallyaccepted
theoriesforthedevelopmentofBOFs:
thehydraulicandbucklingtheories.
• WhilesomepatientswithBOFscangive
aclearhistory,likebeingstruckintheeye
withabaseball,manypatientsfrominner
cityareaswhopresenttotheemergency
departmentarelessclearaboutthe
etiology.
• Traumatotheorbitmayoccurin
isolationoraspartofamoregeneralized
traumaticevent.Inthelattercase,
patientsfrequentlyhaveotherfacial
fractures,mostofteninvolvingthenasal
bones.
• Patientswhopresentwithorbital

traumamaynotgiveacleartrauma
history,eitherbecauseofposttraumatic
neurologicsequelaeorbecauseof
somethingtheyimbibedorinjected
previously.

IMAGING
• Computed tomography (CT) is the imaging study of choice in patients with orbital
trauma.
• It may be necessary to add CT of the face
and/or orbits to the imaging protocol if
only brain CT is requested.
• The use of plain films for the diagnosis of
orbital trauma should probably be reserved
for those cases where CT is unavailable.

Computed Tomography Features
• May find fracture involving the bony cortex
with or without displacement.
• May see soft tissue mass extending into the
roof of the adjacent maxillary sinus.
• Herniated orbital contents usually contain
orbital fat.
• May have complete or partial opacification
of the adjacent maxillary sinus as a result of
hemorrhage and edema.
• Herniation or entrapment of the extraocular
muscles may cause limited ocular motion.
• New fractures may cause associated fluid
and/or air-fluid levels in the maxillary sinus.

• May see intraorbital air and/or air-fluid
levels.
• Multiplanar imaging is most helpful with
axial, coronal, and sagittal views. Threedimensional imaging is helpful and popular
with clinicians.
• BOFFs are usually unilateral.

Magnetic Resonance Imaging
Features
• Magnetic resonance imaging is not usually
used for this entity.
• Bone detail is less clearly demonstrated than
by CT.

Plain Films
• “Black eyebrow sign” is secondary to intraorbital emphysema caused by BOFs. This
9


10

PART I

Trauma and Surgery

sign may be helpful to less experienced radiologists trying to interpret orbital plain films.1
• Plain films are of limited value for orbital
imaging, and CT should be recommended.

CLINICAL ISSUES

Presentation
• Most patients present to the emergency
department with a history of known trauma
to the face or orbit or with a history of
suspected trauma to the head and face but
are “not really sure” what happened.
• The majority of the fractures are secondary
to personal altercations. The more complex
fractures, however, are often related to a
motor vehicle accident or a fall.2
• Associated clinical findings may include:
• Pain and tenderness.
• Enophthalmos.
• May not be apparent until the initial
swelling subsides.
• Diplopia on upward gaze.
• Entrapment of the inferior rectus and
occasionally of the inferior oblique
muscles.
• While muscular entrapment is less
common than previously thought, it
is now believed that herniation of fat
and connective tissue may nevertheless
tether the inferior rectus, causing restriction of upward gaze.3-5
• May be caused by rectus muscle hematoma6.
• Injury to a branch of the oculomotor
nerve (CN III) may restrict upward
gaze.6
• Orbital emphysema.
• Facial paresthesia secondary to infraorbital nerve entrapment or damage.

• Patient feels orbital pressure when blowing nose.
• Epistaxis.
• Concomitant nasal fractures in more
than 50% of cases.

Natural History
• Given�the currently common methods of
inner city conflict resolution, the prevalence
of BOFs appears to be inversely proportional
to that of gunshot wounds (GSWs): as GSWs
increase, BOFs decrease and vice versa.
• A patient with a BOF is likely to come from
a population that includes several patients
with BOFs.

• Other facial fractures are also likely to be
common within such a population, including other types of BOFs.
• Around 50% of patients with BOFFs were
found to have medial blowout fractures
(MBOFs).7
• More than 50% of patients with MBOFs
have nasal bone fractures.8,9
• The male:female ratio is 5:1.
• The left orbit is more frequently involved
because most attackers are right-handed.

Treatment
• Most cases require no special treatment.
• Patients are usually told to not blow their
nose in an attempt to avoid forcing air and

bacteria into the orbit. However, it is not
clear how well patients follow this advice.
• When an acute fracture is recognized, the
patient may be given antibiotics to avoid
spread of the infection to the orbit.
• Surgery is only seriously considered for
complications.

Surgery
• Entrapment requires early diagnosis and
treatment otherwise reduced blood flow
and nerve compression may cause permanent injury.10,11
• Current management favors early surgical
intervention in cases with frank extraocular
muscle entrapment.11,12
• Early intervention has been reported to
resolve diplopia in all entrapment cases.13
• Large floor fractures (more than 50% of
the floor) may require repair using bone
grafting, a metal plate, or synthetic material
such as Teflon.
• Most postoperative floor repairs can be
clearly demonstrated by CT and magnetic
resonance imaging.

Complications
Infection
• See Chapter 29: Cavernous Sinus Thrombosis, and Chapter 44: Orbital Abscess.
Entrapment and Ocular Motility
Impairment

• Diplopia results from damage to or entrapment of the inferior rectus and occasionally
the inferior rectus muscles, limiting upward
or downward gaze.


2

Enophthalmos
• May be the result of muscle atrophy caused
by entrapment, fat necrosis, contracture, or
prolapsed orbital contents.14
• Uncommon in isolated MBOFs.
• Twice as common in combined MBOF and
BOFF (see Figure 2-2).2

PATHOLOGY
Hydraulic Theory
• Fracture caused by increased intraocular
pressure.
• Proposed by King in 1944.15,16
• Upward convexity of posterior orbital floor
receives most of the force transmitted by
the globe.17

Buckling Theory
• The direct transmission of force through
the orbital bones has been confirmed
experimentally.18
• Findings support the theory first proposed
by Le Fort that orbital floor fractures were

produced by direct force transmission
through the orbital rim.19

Protective Process
• A BOF usually protects the most important
inhabitants of the orbit, the globe and the
optic nerve, analogous to the situation in
car crashes when the folding fender disperses the energy of the crash.

Current Consensus
• It is likely that a combination of the hydraulic and buckling forces is responsible
for BOFs.17
• Yano et al. divided BOFs into linear,
punched-out, and burst-type fractures.9
• The orbital floor is frequently fractured
medially near the infraorbital nerve canal,
presumably secondary to structural weakening by the foramen.
• Tests in Rhesus monkeys and cadavers support accepting both the hydraulic and

Blowout Orbital Floor Fracture

11

buckling theories and adopting CT as the
gold standard for evaluating BOFs.

A CLOSER LOOK
• Application of external force to the orbit
by a larger object causes compression and
retropulsion of the orbital contents.

• Transmission of the resultant elevated intraorbital pressure may fracture the thin
floor and/or the paper-thin medial wall.
• Because of its paper-thinness (approximately 0.25 mm), the medial wall was
named the lamina papyracea (Latin for
“layer of paper”). Logic suggests that this
layer would be fractured more often than
the unsupported floor, which is approximately 0.5 mm thick.
• Conventional wisdom conversely holds that
fractures of the orbital floor are more frequent than fractures of the medial wall
lamina papyracea. However, data from a
large inner city university suggest otherwise. In that group of patients, the number
of MBOFs far exceeded the number of
BOFFs.
• Some authors have reported that, among
pure BOFs, isolated medial wall fractures
accounted for around 55% of orbital
fractures.20
• Although rare, blowout fractures of the
orbital roof have been reported.21
• In children, the fracture may spring back
into place like a “trap door,”21 potentially
impounding important orbital anatomy, including the rectus muscles and the nerves,
arteries, and veins that serve those muscles.

Historical Highlights
• Mackenzie investigated and described orbital floor fractures in Paris in 1844.22
• Pfeiffer reported 24 cases of�“internal”
orbital fractures suggesting “retropulsed”
globe causing orbital floor fracture in
1943.23

• Smith and Regan were the first to coin the
term blow-out fracture in 1957, describing
“pure” BOFF without orbital rim fracture.15,21,24


12

PART I

Trauma and Surgery

REFERENCES
1. Feyaerts F, Hermans R: The black eyebrow sign in

orbital blowout fracture, JBR-BTR 92(5):251–252,

2009.

2. Nolasco FP, Mathog RH: Medial orbital wall fractures:
classification and clinical profile, Otolaryngol Head Neck
Surg 112:549–556, 1995.
3. Hammerschlag SB, Hughes S, O’Reilly GV, et al:

Another look at blow-out fractures of the orbit, AJR

Am J Roentgenol 139:
�
133–137, 1982.

4. Koorneef L: Orbital septa: anatomy and function,

�
Ophthalmology 86(5):876–880, 1979.

5.�Koorneef L, Zonneveld FW: The role of direct multiplanar high resolution CT in the assessment and
management of orbital trauma, Radiol Clin North Am 25:
753–766, 1987.
6. Weinstein JM, Lissnar GS: Trauma to the orbit, neurovisual system and oculomotor apparatus, Neuroimaging
Clin N Am 1:357–377, 1991.
7. Zilkha A: Computed tomography of blow-out fracture
of the medial orbital wall, AJR Am J Roentgenol
137(5):963–965, 1981.
8.�Burm JS, Chung CH, Oh SJ: Pure orbital blowout
fracture: new concepts and importance of medial orbital
blowout fracture, Plast Reconstr Surg 103:1839–1849,
1999.
9. Yano H, Nakano M, Anraku K, et al: A consecutive
case review of orbital blowout fractures and recommendations for comprehensive management, Plast Reconstr
Surg 124(2):602–611, 2009.
10. Jordan DR, Allen LH, White J, et al: Intervention
within days for some orbital floor fractures: the whiteeyed blowout, Ophthal Plast Reconstr Surg 14:379–390,
1998.
11.�Bansagi ZC, Meyer DR: Internal orbital fractures in the
pediatric age group: characterization and management,
Ophthalmology 107:829–836, 2000.

12. Egbert JE, May K, Kerten RC, et al: Pediatric orbital
floor fractures: direct extraocular muscle involvement,
Ophthalmology 107:1875–1879, 2000.
13. Brannan PA, Kersten RC, Kulwin DR: Isolated medial
orbital wall fractures with medial rectus muscle incarceration, Ophthal Plast Reconstr Surg 22:178–183, 2006.

14. Converse JM: On the treatment of blow out fractures
of the orbit, Plast Reconstr Surg 62:100–104, 1978.
15. Smith B, Regan WF Jr: Blow-out fracture of the orbit;
mechanism and correction of internal orbital fracture,
Am J Ophthalmol 44:733–739, 1957.
16. Alhamdani FY: Outcomes and impacts of blow-out
fractures of the orbit, Thesis submitted for the degree of
Doctor of Philosophy. Available at: https_theses.ncl.ac.uk_
dspace_bitstream-10443_1516_1_AlHamdani 12.
17. He D, Blomquist PH, Ellis E III: Association between
ocular injuries and internal orbital fractures, J Oral
Maxillofac Surg 65:713–720, 2007.
18. Brown MS, Ky W, Lisman RD: Concomitant ocular
injuries with orbital fractures, J Craniomaxillofac
Trauma 5:41–46, 1999. Discussion 47–48.
19. Jones DE, Evans JN: “Blow-out” fractures of the orbit:
an investigation into their anatomical basis, J Laryngol
Otol 81:1109–1120, 1967.
20. Burm, JS, Chung CH, Oh SJ: Pure orbital blowout
fracture: new concepts and importance of medial
orbital blowout fracture, Plast Reconstr Surg 103:
1839–1849, 1999.
21.�Curtin HD, Wolfe P, Schramm V: Orbital roof blow-out
fractures, AJR Am J Roentgenol 139(5):969–972, 1982.
22. Ng P, Chu C, Young N, et al: Imaging of orbital floor
fractures, Australas Radiol 40(3):264–268, 1996.
23. Pfeifer RL: Traumatic enophthalmos, Arch Ophthal
30:718–726, 1943.
24. Smith, B, Regan WF Jr: “Blowout” fracture of the
orbit: mechanism and correction of internal orbital

fractures, Am J Ophthalmol 44:733–739, 1957.


2

A

Blowout Orbital Floor Fracture

13

C

B

FIGURE 2-1 n A, Coronal orbital computed tomography (CT) showing depressed blowout orbital floor fracture OS
with opacified adjacent maxillary sinus. No inferior rectus muscle entrapment. B and C, Sagittal CTs showing
comminuted orbital floor depressed into the opacified maxillary sinus

A

D

C

B

E

F

G
FIGURE 2-2 n A, B and D, Coronal orbital computed tomography (CT) showing small blowout orbital floor fracture
(BOFF) OD with conspicuous herniated orbital fat shown in stark relief against air-containing maxillary sinus. No
entrapment of adjacent medial rectus muscle. Concomitant medial blowout orbital fracture (MBOF). C, Sagittal
orbital CT demonstrating dehiscent orbital floor with orbital fat herniating inferiorly. Posterior orbital floor bowed
inferiorly. E, Axial CT showing associated MBOF OD. Coronal orbital scout (F) showing plane of axial
image (G) demonstrating linear bone fragment from depressed BOFF, not well demonstrated on other images.


CHAPTER 3

Orbital Exenteration
KEY POINTS
• Definition: Orbital exenteration (OE) is
a radical surgical procedure involving
removal of the entire orbital contents
and periorbital structures. It is usually
performed to treat primary orbital or
periorbital malignancies that invade the
orbit.
• Classic clue: A middle-aged man with
basal cell carcinoma (BCC) near the
orbit. It had been there a “long time
and he thought it would go away,”
but he developed persistent pain and
paresthesia.

IMAGING
Computed Tomography Features

• Absence of all customary contents in an
orbit of normal size.
• Variable amount of residual soft tissue at
orbital apex.
• Possible prior bony wall resection.
• Need to look for bony destruction or focal
areas of abnormal soft tissue growth.
• May see soft tissue enhancement to suggest
residual or recurrent tumor.

Magnetic Resonance Imaging
Features
• Absence of all customary contents in an
orbit of normal size.
• Variable amount of residual soft tissue at
orbital apex.
• Need to look for bony destruction or focal
areas of abnormal soft tissue growth.
• Imaging important for demonstrating perineural tumor spread.
• May see soft tissue enhancement to suggest
residual or recurrent tumor.
• Gadolinium-enhanced fat-saturated T1weighted imaging important, particularly
for detecting perineural tumor spread.
• Magnetic resonance imaging can be used to
follow any suspicious findings sequentially,
14

without the risk of ionizing radiation associated with computed tomography.

CLINICAL ISSUES

Presentation
• OE is a rare occurrence.
• The average age at time of treatment is
53 years.
• Pain may suggest bony invasion or perineural tumor spread.
• Perineural spread of the tumor along branches
of the trigeminal nerve leads to numbness or
pain, possibly causing facial weakness.

Treatment
Surgery
• Following exenteration, the orbital socket
will hopefully heal by the formation of
granulation tissue, or the surgeon can cover
it with a flap or skin graft.1
• Full-thickness skin grafting reduces complications and improves patient acceptance.2
• Cerebrospinal fluid leak may be a complication, necessitating surgical repair.3

Prognosis
• About 25% of exenterations have complicating fistulae, tissue necrosis, persistent bone
exposure, infection, and tumor recurrence.1,4
• Complete tumor removal is achieved in
more than 60% of total exenterations and
80% of subtotal exenterations.
• Incomplete tumor removal is achieved in
less than 40% of cases.1
• The 5-year survival is 65%.1
• The 5-year survival is significantly poorer
when perineural spread is present. Imaging
is important for establishing staging.

PATHOLOGY
• OE in adults is usually performed for
BCC, malignant lacrimal gland (LG) tumors,


3  Orbital Exenteration

sarcomas, meningioma, pseudotumor, fungal infection, infiltrative plexiform neurofibromas (NFs), and metastatic disease.
• OE in children is more frequently performed
for rhabdomyosarcoma.
• The majority (99%) of OEs performed for
tumors are for BCCs or less frequently
squamous cell carcinomas.1
• See Chapter 42: Adenoid Cystic Carcinoma
of the Lacrimal Gland.

DIFFERENTIAL DIAGNOSIS
1. Anophthalmia
• Greek “without eye.”
• Congenital, present at birth. OE usually
performed during middle-age.
• Small orbit with malar prominence. OE
usually normal in size.
• May be unilateral or bilateral. OE is usually
unilateral.

15

• Type I: Evisceration removes the iris, cornea and internal eye contents, leaving the

sclera and EOMs behind.
• A prosthetic scleral shell may be formed
to fit over the existing scleral surface and
is often worn full-time. The scleral shell
may have good motility.
• Type II: Enucleation removes the globe,
leaving the eyelids and adjacent structures
intact.
• An implant may replace lost volume with
the EOMs attached to provide motility.
• Type III: OE removes the orbital contents,
including the globe, optic nerve, fat, EOMs,
and adjacent structures, including the LG.
• OE aims for local control of disease overrunning the orbit, which is persistently
progressive or potentially fatal.

Historic Highlights
• Early exenteration was first described by
Georg Bartisch in 1583 and Gooch in
1767.1,5,6

2. Microphthalmia
• Small eye, from the Greek micros (small)
and ophthalmos (eye).
• Congenital, present at birth. OE usually
performed during middle age.
• Abnormally small globe and orbit. OE usually normal in size.

3. Enucleation
• Removal of globe, leaving eyelids and adjacent structures intact.

4. Evisceration
• Removal of iris, cornea, and internal eye
contents with sclera and extraocular muscles (EOMs) left behind.

A CLOSER LOOK
• Evisceration, enucleation, and exenteration
are the three leading surgical techniques for
removing all or part of the orbital contents.

REFERENCES
1. Tyers AG: Orbital exenteration for invasive skin tumors,
Eye 20:1165–1170, 2006.
2. Croce A, Moretti A, D’Agostino L, et al: Orbital exenteration in elderly patients: personal experience, Acta
Otorhinolaryngol Ital 28(4):193–199, 2008.
3. Ginat DT, Moonis G, Hayden BC, et al: Imaging the
Postoperative Orbit. In Ginat DT, Westesson P-LA, editors: Atlas of Postsurgical Neuroradiology: Imaging of the Brain,
Spine, Head and Neck, Berlin, 2012, Springer-Verlag.
4. Goldberg RA, Kim JW, Schorr N: Orbital exenteration:
results of an individualized approach, Ophthal Plast
Reconstr Surg 19(3):229–236, 2003.
5. Frezzotti R, Bonanni R, Nuti A, et al: Radical orbital
resections, Adv Ophthalmic Plast Reconstr Surg 9:175–192,
1992.
6. Coston TO, Small RG: Orbital exenteration—simplified,
Trans Am Ophthalmol Soc 79:136–152, 1981.


16

A

PART I  Trauma and Surgery

B

C

D

E

FIGURE 3-1  ​n ​A, Axial nonenhanced computed tomography (CT) showing absence of OS secondary to surgical
exenteration. B, Axial enhanced CT showing surgical exenteration of OS. The only visualized remaining soft tissue begins in the orbital apex and extends into the optic canal. C, Axial enhanced CT showing surgical exenteration OS. Slight soft tissue visualized along orbital floor laterally. D, Enhanced sagittal CT showing surgical
exenteration OS. E, Enhanced sagittal CT showing normal OD.