Orbital fractures and head injury 2 Flashcards
What is a lateral wall fracture
A lateral wall fracture is
usually part of a complex fracture, associated with extensive facial injuries. It’s less common as the lateral
wall consists of more solid bone than other parts of the orbit
What is a zygomatic fracture/ displacement
A fracture of the zygoma can occur, but more commonly it is displaced upwards or
downwards from its attachment, which is determined by the direction of the blow. It
may be associated with an orbital floor blow out fracture as well.
What are the characteristics of zygomatic fracture/ displacement
Oedema and haemorrhage
Downward displacement can cause enophthalmos, pseudoptosis and a
flattened cheek bone
Upward displacement can cause exophthalmos and an accentuated cheek
bone
May also have damage to EOM or nerves causing diplopia
May also have disturbed motility of lower jaw if affecting temporomandibular
joint
What are nasa orbital fractures and cause
A fracture to the nasal bones may be isolated or associated with an orbital fracture.
Often caused by direct trauma to the mid third of the face.
What are the characteristics of nasa orbital fractures
Flattened nose
Traumatic telecanthus (12-20%) ~ increased distance between medial canthi
Oedema - swollen medial canthal area
Epitaxis (nose bleed)
Nasal obstruction
Damage to lacrimal apparatus
Emphysema
Damage to inferior oblique origin (or other EOM or nerve)
Lack of skeletal support on palpation of nose
CSF leak – consider a fracture of the cribriform plate
Orbital blow out fractures
A blow-out fracture is a fracture due to an increase in orbital pressure, which causes
the thinnest parts of the orbit to ‘blow out’. The weakest and thinnest part of the orbit
is the maxilla, causing a blow-out fracture of the orbital floor. The next weakest part
is the ethmoid, causing a blow-out fracture of the medial wall
Commonness of blow out fracture
Although different
patterns of injury can exist in different ethnicities, orbital floor blow out fracture more
common in Caucasian and Asian individuals, whereas medial wall blow out fracture
more common in Afro-Caribbean individuals (De Silva & Rose, 2011).
Types of blow out fracture
Pure blow out fracture
Impure blow out fracture
Pure blow out fracture
a fracture of the internal orbital walls only, i.e. orbital floor
Impure blow out fracture
a fracture of the internal orbital walls plus a fracture of the orbital rim
Size of object causing blow out..
often determines the injury. An object
smaller than the diameter orbital rim i.e. golf ball, is likely to cause globe damage. An
object much larger than the diameter of the orbital rim i.e. dash board in RTA, is
likely to cause an impure blow-out fracture, An object the same size or slightly bigger
than the diameter of the orbital rim i.e. fist or tennis ball, is likely to cause a pure
blow-out fracture.
2 mechanisms of injury causing blow out fractures
Hydraulic theory/ blow out
Bucking theory
Hydraulic theory
the force of the object displaces the globe
backwards, increasing the intraorbital pressure with a resulting fracture in the area of least resistance i.e. posterior orbital floor (Smith and Regan, 1959).
Bucking theory
the force of the blow is transmitted through the bone from the
orbital rim to the floor of the orbit.
Bucking theory characteristics
Size of fracture- small
Medial wall- never
Herniation- never
Roof involved- no
Produced by- forced to orbital rim
Hydraulic theory characteristics
Size of fracture- large
Medial wall- always
Herniation- common
Roof involved- no
Produced by- force to globe
Typed of pure blow out fracture
Linear / trap door
Hanging top of hinged bony fragment
Depressed
Comminuted
Types of pure blow out fractures
Linear or trap door: fracture is open and closed after injury with no loss of orbital
contents, yet there may be incarceration of soft tissue/muscle in trap door
Hanging drop of hinged bony fragment: herniation of orbital contents into fracture
Depressed: a piece of the fractured orbit is punched out
Comminuted: fracture of the orbit which shatters into several bony fragments. In an orbital floor blow out fracture of this type the bony fragments are displaced into the
maxillary antrum
Characteristics of orbital blow out fractures
Ecchymosis - ‘black eye’
Subconjunctival haemorrhage
Oedema – swelling
Enophthalmos and pseudoptosis - due to increased orbital space
Anaesthesia / hypoanaesthesia - ipsilateral cheek and upper lip and teeth in
an orbital floor blow-out fracture (if infraorbital nerve affected )
Limitation of ocular movement and diplopia – this is a mechanical defect, so
the limitation will be in the position away from the defect
Orbital floor blow-out fracture – limited elevation (?also depression)
Medial wall blow-out fracture – limited ABDuction (?also ADDuction)
Pain on attempted movement
Globe retraction on attempted movement
Increased IOP on attempted movement
Orbital emphysema - warned not to blow nose
Muscle/ soft tissue entrapment
An extraocular muscle and/or surrounding soft tissue may become trapped in an
orbital fracture site. A trap door orbital floor blow-out fracture is the most common
fracture for this to occur. The inferior rectus and/or surrounding soft tissue become
trapped – this causes restricted elevation and there may also be globe retraction on
attempted elevation.
Medial rectus and trap door
A medial rectus may become trapped in a medial wall fracture has also been reported (Thering & Bogart, 1979).
Findings in trap door fracture
A trap door fracture is more common in children. In a study of 24 children with orbital fractures, 11 were found to have trap door fractures.
Early surgery is important
Symptoms of entrapment
nausea, vomiting, pain on eye movement and oculo-cardiac reflex
(bradycardia, heart block, nausea, vomiting or syncope). Some patients can achieve complete resolution of their symptoms post-operatively (Egbert et al, 2000). Early
diagnosis is important and early surgery is necessary to prevent EOM damage and
improve prognosis (Foulds et al, 2013).
Investigating suspected orbital fracture
Ophthalmic Investigation
Visual acuity
Slit lamp examination (anterior segment & posterior segment)
Measurement of exophthalmos / enophthalmos using a Hertle
exophthalmometer or can use CT scans (Sung et al, 2013; Shah et al, 2013)
Measurement IOP (intraocular pressure)
FDT (Forced Duction Test)
Electromyography/saccadic velocities
Radiological Investigations
X-rays - readily available, but small fractures are difficult to detect and may be
missed
CT scans – more readily available than they used to be. Coronal sections are
taken to determine the extent of the fracture and determine the nature of the
antral soft tissue densities. CT scanning therefore allows visualisation of the
EOM and soft tissues, but the CT evidence of a fracture may be minimal, they
need to be carefully evaluated (Criden & Ellis, 2007)
MRI scans – take longer and may be less readily available. Particularly useful
to see herniation and entrapment more clearly
Heran F et al. (2012) A wander through the land of the orbit. Diagnostic and
Interventional Imaging. 93: 962-974. A nice paper about orbital imaging & talks
through cases of orbital trauma (as well as other clinical findings).
Orthoptic investigation: Observation. Description. Documentation.
Further investigating orbital fracture
Case History
Crucial – may be a recent history of trauma, but may be late presenting,
consider events may be unwitnessed. Consider whether a head injury has
also occurred.
Symptoms
Diplopia – note type and any changes or reversal in different gaze position
Shah et al (2013) found that herniation of soft tissue into orbital floor fracture site (in
small & medium fractures only) were associated with a high risk of diplopia.
Pain, especially on attempted eye movement
Anaesthesia or hypoanaesthesia
Orbital emphysema (air trapped in the orbit) – indicates a fracture of ethmoid
sinuses. Patients are advised not to blow their nose post orbital fracture.
Epistaxis (nose bleed) – advised not to blow the nose after a suspected orbital
fracture.
Signs
Ecchymosis and oedema – lids may be closed. May need to hold lids open to
test VA and examine the eye.
Enophthalmos / exophthalmos
Facial asymmetry – esp. in impure blow out with displacement of orbital rim
Subconjunctival haemorrhage
Hyphaema etc – damage to globe
Unequal pupil sizes - sphincter muscle of iris may be damaged
AHP as appropriate for deviation
VA may need patient to open their eye / lift swollen lid to test VA
Cover Test: with and without AHP
OMs in orbital fracture
Looking particularly for restrictions, but may also see under and
overactions
Typically, mechanical (revise mechanical OM defects)
Restriction of elevation - orbital floor fracture
Restriction of ABDuction - medial wall fracture
Reversal of diplopia – from upgaze to downgaze
Retraction of the globe
Superior oblique defects may indicate trochlear damage
? tissue entrapment (see ‘trap door’ or ‘white eyed blow out’ fracture)
? an associated nerve palsy (see Scolozzi et al, 2022)
? an associated head injury as well
General limitations of gaze are indicative of retrobulbar haemorrhage –
important to consider ON function (VA, CV, CS, VEP)
Pupil function
OM, measurements of deviation (1, 2 and 3 positions of gaze), Hess Chart, Field of
BSV, Field of uniocular fixation, investigation of BSV, Measurement of
accommodation.
Hess – see Hess Area Ratio % (Wood and Adeoye, 2021; Osaki et al, 2022)
Do you suspect there is entrapment of muscle or soft tissue in a fracture?
Its a surgical emergency
Do you suspect a head injury or neurogenic palsy?
There may be improvement in traumatic cranial nerve palsies as well, but the improvement is usually over a longer
period of time.
What further investigations may aid diagnosis?
This may be ophthalmological,
radiological or surgical investigation.
What short and long term management options are there?
Consider orthoptic
conservative options in short term, particularly during an observation period.
Surgical management of orbital fractures aim
The aims of surgical intervention is to restore full orbital volume, restore globe
movement and restore cosmesis; whilst also minimising and preventing early and late sequelae and complications.
-Not all surgeons
will agree on whether surgery needed, type of surgery, surgical approach and the implant material to be used
Timescale for surgical repair of an orbital fracture
Some cases are considered urgent. Often there is a slight delay where the patient
will be observed as the oedema and haemorrhages subside, during this time ocular
motility can be assessed and surgery may be planned more accurately. There is
however a risk that delaying surgery can cause a trapped muscle to become
fibrosed.
If a decision has been made to operate, the surgical approach must also be decided
and this depends on the location and extent of fracture (how much surgical exposure
is needed) and whether there is a clinical finding of muscle entrapment. Imaging
findings can also guide the decision, for example the amount of orbital prolapse
identified. Ultimately it may come down to the surgeon’s preference and technical
ability, for example some may prefer an endoscopy assisted approach (for example Polligkeit et al (2013) reported their experiences using an endoscope through roof of
mouth).
Timescale for surgery opinions
Courtney et al (2000) surveyed all British maxillofacial surgeons
* >50% preferred to operate on orbital fractures 6-10 days post trauma
* 60% routinely sought ophthalmic opinion
* 88% preferred CT scan for imaging
* Subciliary and infraorbital approaches most common for surgical repair
* 66% preferred a silicone elastomer for reconstruction of the fracture
Dulley & Fells (1974) surgery within 14 days recommended for:
* Diplopia not resolving significantly in the early days after injury
* A fracture with large herniation of tissue into the antrum
* Incarceration of tissue in the fracture with resulting globe retraction, and
increased IOP on attempted up gaze
* Enophthalmos > 3mm
Surgical incisions and approaches
- Subciliary or subciliary extended laterally (if need more lateral access to the
orbital rim) - Subtarsal
- Infra orbital (eyelid approach - incision made along the inferior orbital margin
dissecting the orbicularis from the periosteum)
Dr Gemma Arblaster – Year 2
2023 - Caldwell-Luc approach (through the maxillary antrum, between the canine
and second molar teeth) - Transconjunctival approach (through the inferior fornix of the conjunctiva)
- Endonasal approach (through the nose)
- Endoscopic approaches may also be used as they are considered safe and
effective (Cheung et al, 2013)
Materials used for implants
Various biomaterials are available, including autogenous graft material (bone or cartilage), a variety of alloplastic graft materials (silicon, Teflon, rubber, methacrylate, supramid,
polyethylene and titanium (plate / mesh) and allogeneic graft materials (from a
genetically non-identical individual from the same species)
There is also no evidence so far of a long-
term benefit of one implant material type over another (Baek et al, 2014)
Newer surgical intervention
With the advances in 3D modelling and 3D printing it is hoped that the planning of
surgery and the development or personalised orbital implants can improve surgical accuracy and outcomes (Cui et al, 2014). However, results using both surgical
techniques are thought to be comparable (Maher et al, 2022). Currently ‘bespoke’
orbital implants (or patient specific implants) are reserved for more complex fracture repairs. These are unlikely to be available as ‘standard clinical care’ in all centres you will visit.
Complications from surgical intervention include:
Migration of the implant used in reconstruction - ‘extrusion’, which may occur later
Infection – consider the mechanism of injury, most surgeons routinely prescribe
antibiotics post-op (Courtney et al, 2000)
Ectropion - lower eyelid turns outwards
OM restriction and persistent diplopia
Lower eyelid oedema
Retrobulbar haematoma (rare) (Cheon et al, 201)
Later surgical intervention is for
cases of significant enophthalmos
where it is persistent / progressive.
EOM surgery is undertaken later in cases of significant diplopia / motility problems,
often in depression & primary position, there may have also been a neurogenic palsy/ myogenic damage to IR. It needs to be considered if there was a previous fracture repair or not - diplopia post fracture repair may improve with time and some patients
may have residual diplopia relating to orbital implant / neurogenic / mechanical
defect (Loba et al, 2012). Imaging may again prove useful in these cases.
