Fractures of Zygomatic complex and Orbit
Zygomatic bone forming the lateral wall of the orbit and giving prominence to the cheek is commonly involved in facial injuries, representing either the most common facial fracture or the second in frequency after nasal fractures. All zygomatic complex fractures involve the orbital floor and therefore understanding of the anatomy of the orbit is essential for management of these fractures.
The orbital skeleton represents an important anatomic crossroads because of its intimate relationship to the central nervous system, the nose, the paranasal sinuses, the face and the structures related to the support and function of the eye. Maxillofacial injuries of the middle third of face commonly destroys the integrity of the orbital skeleton ranging from blow out to complex comminution. These type of injuries often leads to orbital dysfunction and incapacitating visual dysfunction. The fractures of the orbit are to be approached with caution and it requires precise knowledge of its anatomy.
Since the gross shape of the face is influenced by largely by the underlying bone, the zygoma plays an important role in facial contour. Its disruption also has great functional significance because it creates impairment of ocular and mandibular function. Therefore for both cosmetic and functional reasons, it is imperative to diagnose and adequately treat zygomatic complex fractures.
The fracture of this region is of higher incidence. The incidence, aetiology, age and sex predilection varies depending on the region studied due to social, economic, political factors. Male to female ratio is of 4:1. The peak incidence is during 2nd and 3rd decade.
Orbital fractures are present in all midface fractures with the exception to le fort I, the alveolar process fracture, the isolated Zygomatic arch fracture and the simple nasal bone fracture. Orbital fractures are present in approximately in 90% of all midface fractures either as separate or combined injuries.
The etiological factors road traffic accidents and interpersonal violence. If the fracture is due to domestic violence, left zygoma is commonly involved due to greater incidence of right handed persons. In road traffic accidents both sides were equally involved. Bilateral fractures were uncommon and it usually results from road traffic accidents.
Factors contributing to the high incidence of these fractures include
(i) Zygoma being a prominent position relative to the rest of the facial skeleton.
(ii) A force of only 50 to 80gm is enough to create a fracture in this region of the face.
(ii As society become more mobile and urbanised, motor vehicles accident has
increased in incidence of zygomatic and orbital injuries.
Anatomy of the zygomatic complex.
The Zygoma is a strong bone that gives the prominence of the cheek. It forms the lateral wall and floor of the orbit. It also forms the boundary for temporal and infratemporal fosssae. It is roughly equivalent to four sides of a pyramid with four processes – the temporal, orbital, maxillary and frontal. It articulates with the maxilla, sphenoid, frontal and temporal bones. These articulating bones play a significant role in preventing extensive injury to the zygoma and the face. The zygomatic process of the temporal bone acts as a buttress for the Zygoma against posteriorly directed forces. The Zygomatic process of the frontal bone and the greater wing of the sphenoid bone provide resistance to vertically directed forces upon the zygoma.
The lateral surface is convex and temporal surface is concave. The orbital surface together with greater wing of sphenoid and orbital surface of maxilla form the lateral wall of orbit and floor of the orbit. The temporal process is a narrow, relatively thin projection that articulates with the zygomatic process of the temporal bone to form the zygomatic arch.
Zygomatico frontal and Zygomatico temporal nerves, branches of the trigeminal nerve, exit from the body of the zygoma to provide sensation to the cheek and anterior temporal region. The lateral surface gives origin to zygomaticus muscles and levator labii superioris muscle.
The infra orbital nerve, also a branch of fifth nerve passes through the floor of the orbit, lying in the infraorbital groove, and exit through the infraorbital foramen, which is located in the anterior wall of the maxilla 5 to10 mm below the infraorbital rim. Orbito zygomatic fractures occur in close proximity to these nerves, and injuries in this region of the face may disrupt the sensation provided by these nerves. Masseter muscle attaches to the concave temporal surface of the zygoma and the arch. The temporalis fascia is attached to the frontal process of the zygoma and the zygomatic arch. This fascia produces resistance to inferior displacement of a fractured segment. The coronoid process of the mandible is medial to the zygomatic arch, so any medial displacement of the arch results in mechanical interference and the ensuing trismus.
Anatomy of the orbit
The orbit consists of the bony framework with periocular soft tissues, globe and the protective soft tissue apparatus.
The orbit is a unique bony structure that has the primary purpose of housing and protecting the globe. By 5yrs 85% of the growth of the orbit is completed and growth is completed between 7yrs and puberty. The orbit is a four-sided pyramid with its apex at the optic foramen and base formed by orbital rim.
The bony orbit is formed by union of seven bones: frontal, ethmoid, Sphenoid, maxilla, Zygoma, lacrimal and palatine bones. The orbital rim is very solid and it protects the eye from many injuries. The rim comprises of the frontal bone superiorly, laterally and medially, the zygomatic bone laterally and inferiorly, the maxillary bone inferiorly and medially.
The orbital wall consists of a roof, medial and lateral walls, and a floor. The orbital walls vary in thickness and strength. Fractures of the anterior and middle third of the orbit are common, with the maxillary sinus and ethmoidal air cells acting as shock absorbers and acute volume expansion compartments. Posterior third fracture of the orbit is rare and this commonly results in blindness.
The roof of the orbit is triangular and is formed by the orbital plate of the frontal bone, and the lesser wing of sphenoid. The posterior extent of the roof ends at the optic canal. The roof of the orbit is thin and it separates it from anterior cranial fossa. In the elderly, the orbital roof may become resorbed, resulting in the periorbita becoming fused to the overlying duramater. Anterolaterally is a smooth, broad fossa for the lacrimal gland. Medially 4 mm behind the orbital rim lies the trochlear fovea, where the cartilaginous pulley inserts for the superior oblique muscle tendon. Supraorbital notch is present at the junction of the lateral 2/3rd and medial 1/3rd through which supraorbital nerves & vessels pass.
The lateral wall of the orbit is composed of the greater wing of the sphenoid bone and the frontal process of the zygoma. This is the strongest wall and it might fracture along the thinnest portion along the suture line. This wall is angled at 45o to the medial wall and 90o to the other side lateral wall. This wall is separated at the apex from the roof and the sphenoid by superior orbital fissure. Whitnall’s tubercle is located internally 5mm behind the lateral orbital rim and approximately 1cm below the frontozygomatic suture. This gives attachment to the lateral horn of the levator aponeurosis, lateral canthal tendon of the eyelid, lockwood’s suspensory ligament of the globe and check ligaments of the lateral rectus.
The floor is formed by the orbital surface of maxilla, zygoma and a small portion of palatine bone. The floor is delineated posteriorly by sphenomaxillary fissure. The infraorbital groove originates from the middle of the inferior orbital fissure about 2.5 to 3 cm from the inferior orbital rim. This is converted into a canal halfway anteriorly. It exists via infraorbital foramen 5mm below the lower orbital rim. It transmits the infraorbital nerve and vessels. The floor of the orbit is usually 0.5 mm thick and the thinnest portion is medial to the infraorbital groove and canal.
The medial wall of the orbit is more complex and it is about half the height of the lateral wall as the floor is inclined upwards at 45o to meet the medial wall. The medial wall is made up of the orbital plate of the ethmoid bone (lamina papyracea), the angular process of the frontal bone antero-superiorly, the lacrimal bone antero-inferiorly and lesser wing of sphenoid posteriorly. The orbital surface of ethmoid is extremely thin (0.2 to 0.4 mm) forms the largest section of the medial wall. The medial wall is frequently involved in orbito-zygomatic fractures, primarily in the area of the thin lamina papyracea. Posteriorly and superiorly the optic canal is located within the strong lesser wing of sphenoid. At the junction of the medial wall and roof about the level of optic canal two or three foramina are present which transmit branches of ethmoidal vessels and nerves. The lacrimal sac is tucked into the medial rim between the lacrimal and maxillary bones. This is lined anteriorly and posteriorly by lacrimal crests which gives attachment to the medial canthal ligament, Lockwood’s suspensory ligament. The medial wall is aligned parallel to the anteroposterior axis or median plane of the skull and is extremely fragile because of the presence of the adjacent ethmoidal air cells.
Rontal et al 1979 studied various skulls and gave the mean distance of locating the vital structures in relationship to identifiable fine bone margins.
- Infraorbital foramen to the midpoint of the inferior orbital fissure is 24mm.
- Anterior lacrimal crest to anterior ethmoidal foramen is 24 mm.
- Anterior lacrimal crest to medial aspect of the optic canal is 42 mm.
- Frontozygomatic suture to the superior orbital fissure is 35 mm.
- Supraorbital notch to the superior orbital fissure is 40 mm.
- Supraorbital notch to the superior aspect of the optic canal is 40 mm.
Thus it is safer to commence the exploration from the lateral wall of the orbit. The maximum safe distance of safe exploration is 25 mm from the inferior orbital margin and frontozygomatic suture.
The confluence of the bony walls forms the orbital apex, which is more complex due to the presence of superior and inferior orbital fissure and the optic foramen.
The anterior border of the inferior orbital fissure is approximately 20 mm from the infra orbital rim, so orbital floor exploration should not proceed beyond 20 mm. Structures passing through the inferior orbital fissure include zygomatic nerve, inferior orbital vein to pterygoid venous plexus and some parasympathetic from sphenopalatine ganglion.
The superior orbital fissure runs between the greater and lesser wing of sphenoid. The lacrimal, frontal, nasociliary nerve branches of trigeminal nerve, oculomotor nerve, abducent nerve, trochlear nerve, superior and inferior ophthalmic veins pass through this fissure. These groups of neurovascular structures pass immediately from the cavernous sinus to the superior orbital fissure. This accounts for the optahalmoplegia when injury occurring to this space.
The optic foramen is just medial to the superior orbital fissure and transmits the optic nerve and ophthalmic artery. This is about 45 mm posterior to the supraorbital notch. The muscular cone surrounds the posterior globe and inserts into the orbital apex forming a tendonous ring. The ring surrounds the optic foramen and part of superior orbital fissure including the oculomotor and abducens. Trochlear nerve runs outside this cone and is more thus increasing the risk of superior oblique muscle palsy.
The soft tissue of the orbit
The structures within the orbit can be viewed as a globe surrounded by a muscular cone, in turn surrounded by protective fat and attachments to bony system by suspensory ligaments and attachments.
Lining of the bony orbit is a layer of periosteum known as the periorbita, which becomes the orbital septum superiorly and inferiorly at the orbital rim as it extends into the eyelids.
Interior to the periosteum is a layer of periorbital fat. The fat contains many fibrous septae, which can become trapped in blow out fracture. The fat and the periosteum outside the globe and the extraocular muscles are called the extraconal space. The intraconal space is formed by the extraocular muscle cone and the fascia lining the extraocular muscles. It contains the optic nerve and the intraconal fat.
The eye is protected within the orbit by complex arrangements of fascia and ligaments. Lockwood’s suspensory ligament supports the globe vertically and it has medial and lateral attachments. Medial it is attached to the anterior and posterior lacrimal crest while laterally it is attached to the whitnal’s tubercle. A fascial sheath called Tenon’s capsule surrounds the globe posterior to the cornea and invests around the extraocular muscles. Lateral and medial folds of the Tenon’s capsule form the lateral and medial check ligaments, which resist the posterior pull of the extraocular muscle. Some part of this fascia fuses with the fascia surrounding the inferior rectus and the inferior oblique muscles to form the suspensory ligament. The suspensory ligament prevents the dropping of the globe in case of fracture of the orbital floor.
The six extraocular muscles that form the muscle cone and move the globe are medial, lateral, superior and inferior rectii muscles, superior and inferior oblique. The eyes normally has the capability of moving along a vertical axis, horizontal axis, both axes simultaneously (oblique motion) and rotational axis (torsion). The seventh extraocular muscle Levator palpebrae superioris runs immediately above the muscular cone and it does not move the globe. It invests in the upper eyelid and aids in its retraction. All the extraocular muscles originate from the orbital apex region as a musculo tendinous ring except for the inferior oblique muscle, which originates from medial part of inferior orbital rim. All extraocular muscles are supplied by oculomotor nerve except for superior oblique and lateral rectus. Superior oblique muscle is supplied by trochlear and lateral rectus is supplied by abducens. For normal vision both the eyes requires co-ordinated action. Losses of co-ordination as a result of nerve damage, muscle entrapment or oedema results in diplopia.
The eye is the organ of visual perception and much of the functional anatomy and physiology of the midface is designed to protect and service the globe.
The eye is more or less round and it projects about 3 mm anterior to the inferior and lateral orbital rims. A very thin layer of conjunctival membrane coats the inner lid surfaces and the visible part of the eye up to the cornea which is covered by bulbar conjunctiva. The eyeball is about 2.5 cm in length and is surrounded by three layers: the fibrous layer, vascular layer and the inner retinal layer.
The sclera makes up the posterior five sixths of the tough fibrous layer. The anterior portion is made up of the clear cornea. The cornea is vulnerable to injury and drying out and it should be protected during maxillofacial procedures.
The middle layer is vascular and pigmented. It is composed of the choroid posteriorly and the ciliary body and iris anteriorly. The ciliary body secretes the aqueous humor. Its obstruction results in glaucoma. The pigmented iris is a diaphragm that projects form the ciliary body. The central aperture of the iris is the pupil. Inflammation of the iris and ciliary body as a result of trauma results in traumatic mydriasis (dilation). The lens is positioned posterior to the iris by suspensory ligaments attached to the ciliary process. The lens is biconcave, avascular and transparent. Posterior to the lens is the vitreous humor which comprises four fifth of the eye. It is a clear gel. The inner coat of the eye is the retina, which contains the pigmented cells and outer neural cells. The blood supply to the retina is through the central retinal artery, which travels with optic nerve.
Anatomy of the lid
Eyelid anatomy is necessary for clinical assessment and for various surgical approaches. The lids and adnexa serve to protect the eye and as well as lubricate and clean the corneal surface.
The eyelids are composed of three layers: the outer skin, the middle orbicularis layer and the innermost is the tarsal plate, which is lined by vascular palpebral conjunctiva. The tarsal plate is semilunar and forms the skeleton of the eyelids. At the lid margin posterior to the eyelashes is the grey line junction of the skin and conjunctiva. The upper eyelid has levator muscle attached to the tarsal plate. The orbital septum continuation of the periorbita is attached to the tarsal plate. The eyelids are attached to the bony orbit medial and laterally by medial and lateral canthal tendon. The preservation of the general contour and the integrity of the lid margins are of greatest importance both aesthetically and functionally and the maintenance of the canthal attachments in correct anteroposterior and horizontal planes is essential for normal outline of the palpebral fissure.
BIOMECHANICS OF ORBITO ZYGOMATIC FRACTURES
The fracture patterns of any bone depends on several factors like the areas of weakness and the direction and magnitude of the force. Fracture lines thus created passes through the areas of greatest weakness of a bone or between bones. Thus any forcible blow coming in contact with the prominent and sturdy zygoma, is transmitted to its four weaker articulating surfaces, the fronto- zygomatic, Zygomatico-maxillary, Zygomatico-Sphenoid, and zygomatico-temporal sutures as well as to the adjacent weaker bones that articulate with the zygoma. Because of the sturdier nature of the Zygoma and thin bones surrounding it, it is rare to find a fracture of the body of the zygoma itself.
Ellis mentioned, inferior orbital fissure is the key to knowing the location of fracture lines occurring during zygomatic complex fracture. Three lines of fracture extend anteromedially, superolaterally and inferior direction from the inferior orbital fissure.
1.) One fracture line extends antromedially along the orbital floor through the orbital process of the maxilla, towards the infraorbital rim, frequently passing through the infraorbital rim onto the anterior maxilla superior or medial to the infraorbital foramen, as well as extending laterally and inferiorly on the maxilla under the Zygomatic buttress of the maxilla.
2.) A second fracture line from the inferior orbital fissure runs inferiorly through the infra temporal aspect of the maxilla and joints the fracture line from the anterior aspect under the zygomatic buttress.
3.) The third fracture line extends superiorly from the inferior orbital fissure along the lateral orbital wall posterior to the rim usually separating the zygomatico-sphenoid suture and frequently extending superiorly, laterally and anteriorly creating a fracture in the area of the frontozygomatic suture at the lateral orbital rim.
An additional fracture line classically occurs at the zygomatic arch, usually 1.5mm posterior to the zygomatico temporal suture line (middle of the zygomatic arch). The fracture lines that extend from the inferior orbital fissure are frequently comminuted, except for the fracture in the area of the fronto zygomatic suture, which is usually a linear fracture.
Orbital blow out fracture, are fractures of the orbital floor in which the orbital rim remains intact. The mechanism involved is a sudden increase in intraorbital pressure from a force. This sudden increase in intraorbital pressure generally causes the weakest portion of the orbital floor to fracture, thus preventing orbit from rupturing. This usually fractures medial to the infra orbital groove about 2 cm posterior to the inferior orbital margin. As with injuries to the zygomatic complex, each injury to the bony orbit should be evaluated for variation from the classic location of fractures to the orbito zygomatic region, and a complete ophthalmologic examination should be performed.
In the pathogenesis of the orbito-zygomatic fracture, the pull of masseter and temporalis muscle must be over come at the fracture site for optimal stabilisation and bony healing. There will rotation of the zygomatic complex fracture about the vertical axis and horizontal axis, which will interfere with adequate reduction.
Bony resorption, is a major long-term complication of fracture management. In the case of orbito zygomatic fractures, maintenance of orbital volume is critical. It has been demonstrated that one of most common cause of posttraumatic enophthalmos is displacement and resorption at the fracture site. A critical assessment of the clinical studies on orbito zygomatic fracture shows that
1) A small subset of orbito zygomatic fractures that can be treated with reduction only. This includes only low velocity, non comminuted fractures that are stable post reduction. Close follow up is needed to detect delayed displacement and deformity.
2) High velocity injuries with communication and displacement, mandate open reduction and internal rigid fixation…
3) Miniplate or microplate fixation is the best tolerated and provides optimal rigid stabilisation, with the lowest rate of attendant complication.
Many classifications have been proposed. These include Mclndoe (1941), Moore and ward (1949), Rowe (1960), Knight and North (1961), Rowe and Killey (1968), Himmelfarh (1968), and Spiessl & Schroll (1972). The classification systems were based on the location and the type of displacement seen. Classifications were also based on the amount of stability after reduction and the need for fixation.
Classification of Zygomatic complex fractures Knight & North 1961
Based on direction of displacement in waters view radiograph.
Group I Nondisplaced fractures – cases in which there is no clinical or radiographic evidence of displacement; no treatment required.
Group II Arch fractures – A pure fracture of the zygomatic arch. The classical three fracture lines produce a ‘V’ shaped deformity.
Group III Unrotated body fractures – Caused by a direct blow to the zygomatic prominence. Zygoma is driven posteriorly and medially, producing a flattening of the cheek. Water’s view shows a displaced infra orbital rim inferiorly and medially at the buttress.
Group IV Medially rotated body fractures – Caused by a blow from above the horizontal axis of the zygoma. Bone is driven medially, inferiorly and posteriorly with rotation. The X rays shows displacement inferiorly at the infraorbital rim and either outward at the malar buttress or inward at the frontozygomatic suture.
Group V Laterally rotated body fractures – Caused by a blow below the horizontal axis of the bone. Zygoma is displaced medially and posteriorly with lateral rotation. The radiograph indicates upward displacement at the infraorbital rim and lateral displacement at the frontozygomatic suture.
Group VI Complex fractures – these have additional fractures across the body of zygoma.
Classification of Zygomatic complex fractures Rowe & Kiley 1968
Modified North & Knight classification by giving consideration to the periosteal envelope of the bone and adequacy of the bony apposition at the fracture interface.
Classification of Zygomatic complex fractures Yanagisawa 1973
Group I Nondisplaced fractures – no treatment required.
Group II Arch fractures – A pure fracture of the zygomatic arch.
Group III Medial or lateral rotation around a vertical axis.
Group IV Medial or lateral rotation around a longitudinal axis.
Group V Medial or lateral displacement without rotation.
Group VI Isolated rim fracture.
Group VII All Complex fractures.
Classification of malar fractures Spiessl & Schroll 1972
Type I Zygomatic arch fracture
Type II Zygomatic complex fracture – – no significant displacement
Type III Zygomatic complex fracture – – partial medial displacement (kinking at the FZ suture)
Type IV Zygomatic complex fracture – – total medial displacement. (Complete ≠ of FZ suture).
Type V Zygomatic complex fracture – – dorsal displacement. (2 ≠ sites in zygomatic arch).
Type VI Zygomatic complex fracture – – inferior displacement.
Type VII Zygomatic complex fracture – – Comminuted fracture
Classification of Zygomatic complex fractures Larsen & Thompson 1978
Group I Nondisplaced fractures requiring no treatment – During the initial evaluation, if there is any doubt about stability, revaluation should occur 1 week after injury.
Group II All fractures requiring treatment – This is further subdivided into fractures that are stable and fractures that are unstable after reduction.
Classification of malar fractures Eberhard Krüger 1986
- Fractures of Zygoma
- No significant displacement
- Partial medial displacement
- Total medial displacement
- Dorsal displacement
- Inferior displacement
- Comminuted fractures
- Fractures of Zygomatic arch
- Complex fractures
- Centrolateral midface fractures
- Zygomatico-maxillary fractures
- Zygomatico-mandibular fractures.
Classification of Orbital fractures Rowe & Williams 1985
Zygomatic complex fractures
- Fractures stable after elevation
- Arch only (medially displaced).
- Rotation around vertical axis
- i) Medially
- ii) Laterally
- Fractures unstable after elevation
- Arch only (inferiorly displaced).
- Rotation around horizontal axis
- i) Medially
- ii) Laterally
- Dislocation en bloc
- i) Inferiorly
- ii) Medially
- Comminuted fractures
Isolated fractures of the orbital rim
- Superior rim
- Lateral third (lacrimal recess)
- Central third (supraorbital nerve)
- Medial third (frontal sinus)
- Inferior rim
- Central third (infraorbital nerve)
- Medial third (inferior oblique margin)
- Medial rim
- Medial canthal ligament
- Lacrimal passage
- Lateral rim
- Lateral canthal ligament
- Suspensory ligament
Isolated fractures of the orbital wall
- Anterior fossa
- Levator palpebrae superioris / superior rectus
- Frontal sinus
- Infraorbital nerve & vessels
- Inferior rectus / inferior oblique
- Medial wall
- Lacrimal sac & nasolacrimal canal
- Ethmoidal sinus
- Medial rectus
- Suspensory ligament
- Lateral wall
Superior orbital fissure & related structures.
Complex comminuted fracture
Classification of zygomatic fractures Zingg et al 1992.
Type A Incomplete fractures
Isolated lateral orbital rim
Isolated inferior orbital rim
Type B Monofragment malar or classic tetrapod fractures
Type C Multifragmented fractures
The various types of fractures are differentiated principally according to the type of fracture dislocation.
Several signs and symptoms accompany zygomatic fractures. The presence and magnitude depends on the extent and type of zygomatic injury. The signs and symptoms accompany zygomatic fractures:
Periorbital ecchymosis and oedema, Flattening of the malar prominence, flattening over the zygomatic arch, pain, ecchymosis over the maxillary buccal sulcus, deformity of zygomatic buttress of the maxilla, deformity of the orbital margin, trismus, abnormal nerve sensibility, epistaxis, subconjunctival ecchymosis, crepitation from air emphysema, displacement of palpebral fissure, proptosis, unequal pupillary levels, diplopia, and enopthalmus.
In total medial displacement, the orbital rim is completely severed at the fronto zygomatic suture. The Zygoma is depressed in the orbital region as well, leading to reduction in size of the orbit. This can lead to exophthalmos, which may be aggravated by further haematoma. On the other hand with a defect of the floor of the orbit, orbital tissue may prolapse into the maxillary sinus so that enophthalmos would result due to medial displacement. The telescoping intrusion of the Zygoma into the orbit and maxillary sinus can lead to incarceration and injury of orbital fatty – tissue and musculature causing diplopia as a result of disturbances of mobility. As the medial fracture lines is always in the region of the infra orbital nerve, that nerve is pinched or torn in medial displacement fractures.
Duker and scheduble (1974) found loss of sensation in 92% of isolated fractures of the Zygoma. Narrowing of the maxillary sinuses and orbit are seen in radiographs of the paranasal sinuses in this type of fracture.
When forces impact frontally, the zygoma can be displaced dorsally. This leads to compression of the Zygomatic arch, which fractures at two points. The resulting enlargements of the orbit in the dorsal direction and the possibility of prolapse of the orbital tissue into the maxillary sinus can lead to enophthalmos and double vision.
Inferior displacement arises when force impinges on the body of the Zygoma obliquely from above. Temporal fascia prevents inferior displacement of the zygoma by its broad attachment. The frontal process of the Zygomatic bone may be titled dorsally or forward, In this type of displacement, the orbital cavity is enlarged. This leads to exophthalmos with the eye lowered and double vision. Sagging of the lateral wall of the orbit leads to displacement of the palpebral fissure in the lateral region in a caudal direction (antimongoloid).
The total medial fracture dislocation can lead to restriction of mouth opening as a result of impingement of the coronoid process on the zygoma.
Management algorithm for zygomatic complex fracture
The mechanism of injury is of primary importance to aid in the location of fracture. High velocity injury is more likely to have displaced comminuted fractures than with low velocity injuries.
In the presence of high velocity facial trauma, the index of suspicion should be higher for associated injuries like occular injuries or possible cervical spine damage.
A direct lateral blow would often result in isolated arch fracture or an inferiorly displaced zygomatic complex fracture. A frontal blow usually is associated with posteriorly and inferiorly displaced fracture.
The patient might usually complaints of pain, periorbital oedema, and ecchymosis. There might be paresthesia or anaesthesia over the area supplied by infra orbital nerve. Patients might complaint of restricted mouth opening when the arch is displaced medially. There is frequently epistaxis and diplopia may result from the entrapment of muscles and displacement of the globe. This becomes obvious within 2 to 3 days.
Ecchymosis and oedema are the most common early clinical signs present. Flattening of the cheek is seen in depression of the malar eminence. Downward displacement of the zygoma produces an antimongoloid slant to the lateral canthus, enophthalmos and accentuation of the supra tarsal fold.
Palpation is the hallmark in the diagnosis of fracture displacement. The zygoma, zygomatic arch and the entire rim of the orbit is palpated for tenderness, step defect or separation of the sutures. The zygomatic buttress is also palpated.
The mandibular movements are evaluated to rule out the impingement of the zygomatic arch over the coronoid process.
A complete ophthalmological examination is critical. This includes an examination of visual acuity, pupillary response to light, occular movements, globe position and a fundoscopic examination for evidence of hyphema or retinal detachment.
Deficits in facial sensation, particularly within the distribution of the infra orbital nerve are identified.
History and physical examination usually establish the diagnosis of the zygomatic fracture. Radiographs are helpful in confirming, medicolegal documentation and in some cases to establish the extent of bony damage.
Useful plain facial radiographs include the submento vertex view, waters’view, Caldwell view, lateral views, tomograms and computed tomography.
Waters’ view is the best radiograph for evaluation of zygomatic complex fractures. It is posteroanterior projection with head positioned at 27o to the vertical plane. This projects the inferior orbital rim, the maxillary sinuses and the lateral orbits. This also aids in diagnosing the orbital blow fractures.
The Caldwell view most accurately assesses the zygomaticofrontal suture.
Submentovertex “jug handle” view is helpful in visualising the fractures of the zygomatic arch and malar projection.
Continued suspicion of an orbito zygomatic fracture based on the radiographic data mandates thin slice CT Scanning in the axial and coronal planes. This is critical in determining degree of displacement as well as associated orbital fractures.
ZYGOMATIC COMPLEX FRACTURES – MANAGEMENT
Since Duverney 1751 used closed reduction for medially displaced zygoma fracture various treatment modalities have been advocated. The schemes of treatment for zygomatic complex fracture range from
- Observation (No treatment).
- Indirect reduction with
- No fixation
- Temporary support
- Direct fixation
- Indirect fixation
- Direct reduction and fixation
- Immediate reconstruction by bone grafting for orbital floor fractures
- Delayed reconstruction by osteotomy and grafting
- Late restoration of contour by onlay grafts.
The optimal time for surgery
This should give consideration to the following factors
- Presence of ophthalmic injuries
- Progressive proptosis.
- Deterioration in visual acuity.
- Visual integrity of the unaffected side.
- Necessity for immediate operation in relation to other facial and general condition.
- The medical condition of the patient
Any manipulation of the bones of the orbit is contraindicated when there is any risk of injury to the eyeball or to its contents or from aggravating existing haemorrhage either from an intraocular or retrobulbar source.
Progressive proptosis following trauma is indicative of retrobulbar haemorrhage, usually of the intraconal variety, and may be accompanied by changes in the pupillary reflex and visual acuity.
In conditions of pre-existing blindness in the other eye, or vision has been lost in the other eye as a result of the trauma, an extremely conservative approach is to be adopted. Surgical procedures may be deferred or avoided.
Orbital injuries as a result of fall precipitated by general medical conditions as coronary thrombosis, cerberovascular disaster or severe anaemia contraindicate an early surgical intervention.
If general anaesthesia is to be administered for other injuries surgical intervention can be taken up for management of zygomatic complex along with other maxillofacial injuries.
If the above conditions do not apply, it will be ideal to defer the surgical procedure for 5 – 7 days, particularly in the case of complex orbital floor fracture. This period will aid in resolution of the gross oedema and permit a more detailed examination of the eye, assessment of diplopia and provides an improved radiograph, as the antrum would not be filled with blood. The surgical procedures are not to be delayed beyond 10 days, as the development of fibrosis will increase difficulty. After 3 – 4 weeks fractures would have clinically firmly united.
Treatment of the zygomatic complex fractures
Appreciable number of cases of zygomatic complex requires no treatment. Apart from medical contraindications, cases of undisplaced zygomatic complex and cases of stable, minimally displaced fractures which following union would not result in cosmetic or functional deformity does not require any treatment. Patients are to be observed longitudinally for signs of displacement, extraocular muscle dysfunction and enophthalmus after swelling resolves. Care is necessary in interpretation of radiographs. An absence of significant displacement at frontozygomatic suture and infra orbital rim does not exclude an unacceptable displacement at the prominence of the zygomatic bone since a rotation around these points, and the middle of the zygomatic arch, may have taken place resulting in impaction into the antral cavity.
This involves procedures that disimpact and reduce the fracture by direct application of instruments deep to the temporal surface of the zygomatic bone through an indirect approach remote from the fracture line. Fractures that are stable after reduction does not require fixation, while unstable fractures are fixed temporarily or permanently.
There are many techniques that have been employed for this operative approach.
- Temporal fossa approach (Gillies).
- Upper buccal sulcus approach (Keen).
- The Cheek approach (percutaneous)
- The nose (transantral).
Temporal fossa approach
This method was introduced by Gillies et al 1927 for elevation of zygomatic arch and the zygomatic complex.
The rationale for this procedure is the fact that temporal fascia is attached to the outer aspect of the zygomatic bone and superior aspect of the arch. Deep to temporal fascia there is a potential space or tissue plane above the temporalis muscle, along which long instrument can be introduced to engage the temporal surface of the zygoma and medial surface of the zygomatic arch.
The technique involves shaving of the hair from the temple region (around the area of bifurcation of temporal artery). An incision of 2.5 cm long is made above and parallel to the anterior branch of temporal artery. Dissection is carried down to the temporal fascia. The fascia is incised and a Howarth periosteal elevator is introduced in a downward and forward direction as far as the temporal aspect of the zygomatic bone. The periosteal elevator is withdrawn and then Bristow’s orthopaedic elevator or Rowe’s modification of Bristow’s elevator is introduced to engage the zygoma. Rowe’s elevator has a blade and an handle similar to the Bristow’s elevator, but it also incorporates a lifting handle which is attached by a strong hinge with a positive stop at the origin of the handle. The external or lifting handle is of the length of the blade and aids in orienting the blade accurately and giving a parallel force on the blade when force is applied. The reduction is often accompanied by an audible click. The fracture reduction is verified by palpating for the persistence of step defect. The temporal fascia is closed with interrupted absorbable sutures and skin edges approximated. Postoperatively, care is taken to avoid pressure over the fractured site until union is complete at the end of approximately 3 weeks.
Upper buccal sulcus approach (Keen)
This technique was introduced by Keen in the early 20th centuary. The major advantages of this approach are:
- It is an intraoral approach and spares a skin incision.
- The approach is more direct.
- Less dissection is required.
- Reduction vector is more ideal
- No major vessels are encountered
An approximately 1.5 cm incision is made in the buccal sulcus inferior to the zygomatic buttress. A periosteal elevator is introduced upwards supraperiostealy to contact the deep or infra temporal surface of the zygomatic bone thus enabling upward, forward and outward pressure to be applied. For elevation various elevators can be used like Bristow’s, Rowe’s, Taylor Monks etc.
Quinn 1977 has described a modification of the method, which is of particular value in the case of medially displaced fractures of the zygomatic arch. This employs a lateral coronoid approach through an incision situated over the anterior border of the ramus. The incision is deepened by blunt dissection in a supraperiosteal plane lateral to the coronoid process until the zygomatic arch is reached. An elevator is used to raise the fractured segment.
This method consist of inserting a hook through the skin below and behind the prominence of the zygomatic bone so that it engages the deep aspect and allows reduction by strong outward traction of the handle of the instrument. This technique is also useful in case of isolated fracture of the zygomatic arch. Poswillo gave the exact location of the initial stab incision at the intersection of a perpendicular line dropped from the lateral canthus and a horizontal line extended posteriorly from the alar margin of the nostril.
Instead of using a hook, insertion of Carroll-Girard screw into the body of zygoma have been advocated for percutaneous approach.
Intranasal transantral approach.
This technique is employed by certain otorlinolarygologists but not used commonly. An opening is made into the antrum below the inferior meatus at the same location for intranasal antrostomy. A curved instrument like Urethral sound is used to manipulate the fractured bone.
Fixation following indirect reduction.
Fixation following fracture reduction is required in case of unstable fracture after reduction. Lack of stability of a reduced zygomatic complex can lead to displacement with subsequent functional and aesthetic deformities. These include facial deformity, occular dysfunction, masticatory impairment, nerve dysfunction, and combination thereof.
Elements that contribute to unstable fracture fixation include:
- Muscular forces across the fracture lines.
- Type of fracture.
- Bone loss at the fracture site.
- Displacement of fracture with disruption of the enveloping periosteum or temporalis fascia.
- Lack of bone thickness at the infra orbital rim and residual fibrosis and resorption of the fracture line when treatment is delayed.
Stability of zygomatic fractures depends upon the type of fracture than the type of fixation used. Rowe reported the factors for instability as:
- Those fractures that are rotated around the horizontal axis (Medially or laterally).
- Fractures that are dislocated enbloc, and
- Comminuted fractures, such as many fractures of the infra orbital rim and maxillary buttress, are unstable.
Also, fractures with bone loss at fracture site are inherently unstable. In additions severely displaced fractures are often unstable because the enveloping periosteum or temporalis fascia has been disrupted.
The longer the time period prior to reduction and fixation of a zygomatic fracture the less chance that the fracture will be stable owing to the development of fibrosis and eburnation of the fractured bony ends.
The Need for Fracture Fixation
If a fracture is not stable after reduction or cannot withstand digital pressure on the malar eminence, then fixation is required.
The fixation is applied only when indicated, if there is any question regarding the stability of a reduced zygomatic fracture, it is prudent to apply fixation.
Methods of Fracture Fixation
The Zygomatic complex is a tetrapod with four buttresses at the frontozygomatic region, infra orbital rim, maxillary buttress and zygomatic arch. Fracture fixation is most often applied at these buttresses.
The location of fixation is important. The frontozygomatic region is the strongest pillar of the zygoma therefore it is the most important point of fixation. The maxillary buttress is the best site for fixation to oppose the direction and force of the masseter muscle. The infra orbital rim is a poorer choice for the site of fixation due to lack of bone thickness.
Fixation can be by temporary, direct or indirect fixation. Temporary fixation is by means of antral packing. Direct fixation after fracture reduction is done by means of wire osteosynthesis or by use miniplate at the fractured site. Indirect fixation is achieved by means of Kirsehner wires and external pin fixation techniques.
A number of materials have been placed in the maxillary sinus in an attempt to support the fractured zygoma or orbital floor. These include balloons, penrose drain materials, plastic cubes, penrose drain stuffed with gauze and strip gauze. The strip gauze is impregnated with iodoform or antibiotic ointments or white head’s Varnish. Antral packing is left in place for 14 days after initial placement. Antral packing is indicated when the zygomatic complex is unstable following reduction, when gross comminution of the zygomatic complex has occurred and when comminution of the orbital floor without bone loss is present. For the antral packing to be effective, there must be total stability of other bones that comprise the maxillary sinus and other process of the zygomatic complex, or they may be displaced.
Antral packing considered only in situation in which severely comminuted zygoma fracture is there and the application of rigid fixation is not possible.
This implies that the zygomatic bone will be rigidly secured to some point elsewhere on the facial skeleton until the union has occurred, after which the connecting apparatus is removed.
This is achieved by the use of
- Internal medullary pins or wires
- External pins and rods that are attached by universal joints
The osteosynthesis effected by transosseous wires alone will provide considerable amount of stability, but lacks absolute rigidity. This has been overcome with the use of miniplates, so the use has indirect technique has largely been reduced. This technique of providing fixation is indicated when there is gross loss of of bone in the region of the Fronto-zygoamtic suture and inferior orbital rim. The indirect fixation is done to other stable structures such as zygomatic bone, frontal bone, maxilla etc as in
In Zygomatic-zygomatic (transmaxillary) fixation the opposite sound zygoma and nasal structures are used for cantilever support of the reduced zygomatic bone.
In Naso-zygomatic fixation a transnasal Kirschner is used to stabilise the zygoma from contralateral frontal process of the maxilla to the natral surface of the zygoma.
In zygomatico-palatal fixation is by use of wires obliquely towards the contalateral palatal process at its junction with the lateral wall of the nose.
Maxillo-zygomatic fixation is by use of external pins and joints stabilised to the maxillary teeth by means cemented cap splint.
Fronto-zygomatic fixation is by use of pins and joint to the zygoma and the zygomatic process of the frontal bone. This is also done by fixing the reduced zygoma to halo frame.
Indirect Fixation by Kirschner wires
Use of the internal K wire fixation has been shown to be reliable, safe and stable.
Three different placement techniques are there.
- The transfacial approach, in which the pin is inserted through the stable zygoma and nasal cavity and into the fractured Zygoma.
- The trans nasal approach – in which the K wire is inserted through the fractured Zygomas and nasal cavity into the maxilla.
- The trans palatal approach where in the K wire is passed from the fractured zygoma to engage the palatal process of the contrallateral maxilla at the lateral wall of the nose.
The wires are removed 3 to 6 weeks after placement.
– A minimal amount of equipment is necessary and usually readily
- The technique is fast and easy
- Minimal scaring
- Fixation is stable to some extent
– Zygoma must be properly reduced prior to insertion.
– Second procedure is needed to remove the pin.
– The orbital contents or naso endotracheal tube could be impinged by the pin.
- These techniques are ineffective when there is comminuted fracture.
- The rigidity is less when compared to miniplate fixation.
Indirect fixation by External pins:
External fixation of the Zygoma following reduction, via a hook extension and a plaster head cap, rests on extension efforts of stenzol (1902) and on the apparatus proposed for extension of the mandible by Wassmund (1927) and Rehrmann (1935).
Following percutaneous reduction and removal of single tined hook, a rentention hook is placed through the puncture channel. This hook is connected to a plaster head cap elastically with a rubber band or by use of the spring force of the bar to which it is connected. External fixation may be undertaken on a haloframe, or to another pin placed in the zygomatic process of the frontal or to the maxillary teeth by means of cap splint. The apparatus removed after 8 to 14 days.
The disadvantage is that the apparatus is protruding out and produces discomfort to the patient.
This is indicated when there is lack of stability to the reduced fracture segment of zygoma. This is done by means of
- Intraosseous wiring
- Rigid fixation by means of miniplate fixation and lag screws.
Surgical approaches for zygoma and orbital floor
Various approaches are used to access the zygoma and orbital floor for direct fixation and for exploring the orbit. The approaches used for direct fixations of zygoma uses incisions placed around the orbit, coronal approach and intraoral approach in the zygomatic buttress region. The orbital region exploration is approached by placing incisions in and around the orbit.
The surgical approach used for direct fixation of zygoma are
- Lateral eyebrow approach
- Subciliary approach
- Infraorbital approach
- Subconjunctival approach
- Bitemporal / Bicoronal approach
- Buccal sulcus approach
As a rule, placement of single intraoseous wire at the frontozygomatic suture and on the lower orbital margin suffice.
The Supra Orbital Eyelid Incision
(Dingman and Natvig 1964, Kruger 1964, Rowe and Killey 1968, Spiessel and Schroll 1972)
Thin incision serves to expose the lateral orbital margin. Following separation of the muscle fibers and periosteum, the fracture site is exposed at the frontozygomatic sutures. This lies deeper than the end of the incision, should be lengthened laterally downward not further than the level of the palpebral fissure, because a longer incision is cosmetically undesirable and because the lid fibers of the facial nerve could be damaged in the process. When necessary, the incision may be lengthened medially along the eyebrow to permit treatment of a typical fracture lines at the Supraorbital margin.
Approaches to orbital floor
There are various ways to gain access to the lower orbital margin. These include.
- Infra orbital approach
- Subciliary approach
- Trans conjunctival approach
- Lower eye lid incision
The infra orbital incision
(Thoma 1958), Kazanjian and Converse 1959), Kruger 1964, Rowe and killey 1968, Luhr 1971, Spiessl and Schroll, 1972, Albright and Mefarland 1972).
This incision lies directly above the lower orbital margin. After incision of the skin and the orbital part of the orbicularis oris muscle, the infra orbital margin is exposed at the fracture site.
Advantages of the incision: –
– Short path to the infra orbital margin.
– Avoidance of the orbital septum.
– Clear line of vision.
– The possibility of lateral extension of the incision.
Disadvantages:- (Becker and Austerman 1977)
– Post traumatic cicatrical distortion of the skin
– Lid edema.
The lower Eye lid Incision
It is a step shape was described by converse et al (1961).
The orbicularis muscle is divided more deeply than the skin.
Disadvantage – Lateral repositioning of the orbicularis occuli muscle is not always ideal and distortion of lower lid may arise (Georgiade 1972, Becker and Autermann 1977)
Subciliary Skin Incision
( by Rankow and Mignogna 1975)
Deeper divisions of orbicularis occuli.
Disadvantage:- The separated think lid skin does not adapt well to be musculature.
Albright and mefarland (1972), Becker and Austermann (1977) and Luhr (1971) therefore prefer the mid lower eyelid incision without step deformation.
The Trans Conjunctival Approach
(Bourquet 1923), Tenzel and miller 1971, Tassier 1973.
Here the incision is in the region of the conjunctiva, eliminating the external scar. Good experience with this technique reported by kazanjian and converts (1974) Lynchetal (1974) and Schule and Weiman (1975). This is by two types preseptal and retroseptal approach.
After atropinization of the lower lid, the palpebral conjunctiva is incised below the tarsus, and the anteriorly placed orbital septum is divided as well. Dissection is than continued in front of the orbital septum to the infraorbital margin.
This is another way of approaching the orbital floor by trans conjunctival approach.
Disadvantage – View is not clear. Occasional it might result in scar distortions of the lower lid which are difficult to correct.
The approaches described are sufficient, as a rule, for transosseous fixation of the Zygoma. After elevation of periosteum at the orbital margin on its external surface, the fracture sites are exposed. Then the periosteum of the orbit is carefully elevated with an elevator. With reduction complete, holes are drilled at both sided of the fracture site at the orbital margin for the transosseous wires. Contents of the orbit protected during the procedure by an elevator. Before the ligatures are tied securely, the correct positioning of Zygoma is checked. When the ligatures have been tightened and the zygoma in proper position, the incision may be sutured. Strains avoided postoperatively, soft diet given.
Transosseous wiring fixation on the orbital margin can be ascribed to Gill (1934) other description provided by Adams (1942) Thoma (1958) Kazanjain and Converse (1959, 74) etc.
The indication for open reduction with direct transosseous wiring at the fracture sites at the lower and lateral orbital margins are provided when an orbital exploration is required simultaneously, when a comminuted fracture is present and when a percutaneous reduction has failed.
Internal fixation of zygomatic fractures by means of miniplates and lag screws
The best method of providing stable fixation to an unstable zygomatic fracture is to rigidly secure it internally with bone plates.
Advantages :- Three dimensional stability,
Faster bone healing (Primary bone healing).
Disadvantages: larger incision
More extensive periosteal stripping of bone
Extreme retraction of wound edges.
Need for technical expertise and cost.
A bone thickness of 2mm is adequate to allow stable fracture fixation with plates and screws.
So rigid internal fixation can be placed at fronto-zygomatic region, maxillary buttress, infra orbital rim and at the zygomatic arch.
Four point fixation with plates at the fronto-zygomatic region, infraorbital rim, maxillary buttress and zygomatic arch is stable. This technique is usually performed on communited zygomatic complex fractures or fractures associated with extensive midfacial trauma.
Three-point fixation with bone plates at the frontozygomatic region, infraorbital rim, maxillary buttress or zygomatic arch has also been shown to be stable.
Rudderman & Mullen 1992, have shown that single point fixation at one of the buttress fractures would result in instability due to translations and rotational forces. Two-point fixation would also result in instability. For best form stability requires fixation at all the three buttresses.
Bone plates and screws with a thinner profile and smaller overall size have been advocated for rigid internal fixation of zygomatic complex fractures.
The added advantage of these fixation devices include a decreased bulk and palpability in the area of fixation within overlying skin and the implantation of less total metal.
In the regional of the midface special ASIF miniplates and 2mm screws. The mini DCP that makes compression osteosynthesis possible has screw holes designed according to the spherical gliding principle.
For making the drill holes, a 1.5mm twist drill bit and a small air powered drill are necessary. For drilling at the orbital margin, there is a special orbital drill guide. One can also use a drill and tap sleeve or an eccentric drill guide and protect the orbital contents with an angled elevator passed around the orbital margin. A depth gauge, a 2mm tap, and a screwdriver also belong to the armamentarium.
For lag screw osteosynthesis, miniscrews with a screw diameter of 1.5mm are used, the 1.1mm twist drill bit for the thread hole corresponding to the core diameter of the screws. For the gliding hole, 1.5mm twist drill bit is needed. The drill guide and tap have an outer diameter of 1.5mm. The depth gauge is same as for the 2mm screws.
Direct reduction and fixation
Here the fracture is approached directly and fixed directly by means of intraosseous wires or miniplate fixation.
ORBITAL FRACTURES AND MANAGEMENT
Fractures of the walls of the orbit are seen along with fractures of zygomatic complex, nasoethmoid complex, midface fractures, frontal bone fractures or as an isolated fractures of orbital floor.
Fractures involving the orbit can be classified as
- Zygomatic complex fractures
- Naso-orbito ethmoidal complex fractures
- Internal orbital fractures
Zygomatic complex fractures are the most commonly involved fractures of the face secondary to nasal fractures. These fractures are also the most common occuring fractures of the orbit. Zygomatic complex fractures are often displaced in an inferior, posterior and medial direction and the complex fulcrums about the frontozygomatic suture. Various classification system have been proposed but the one by Jackson is notable
Type I Nondisplaced
Type II Segmental fracture of orbital rim
Type III Tripod fracture
Type IV Fragmented
Naso-Orbito-Ethmoid complex fractures often occur following blunt trauma to the midface. These fractures primarily result in cosmetic deformity such as flatenning of the nasal dorsum and widening of the intercanthal distance. This can occur as a result of disruption of one or both of the medial canthal ligaments. The fracture ranges from minimal displacement of a large segment of the medial orbital rim to severe comminution with complete avulsion of the canthal ligament from the bone.
Internal orbital fractures
Internal orbital fractures can occur in numerous patterns. Thay are often described by their location and size of the defect. Three patterns of internal orbital fractures are seen
Linear fractures maintain periosteal attachments and therefore do not result in a defect, however they can result in a significant enlargement of the orbit.
Blow-out fractures are the most commonly occurring injury and are limited to one wall, with a defect less than 2 cm in diameter. Blow-out fractures most commonly occur in the anterior and middle part of the floor. They can also occur in the medial and superior walls, where they present as blow-in type of fracture.
Complex fractures consist of extensive fractures that affect two or more orbital walls, may involve the posterior orbit and also the optic canal. This type of fracture is associated with fractures of the facial skeleton such as Le Fort II, III and also frontal bone fractures.
Diagnosis of orbital injuries in midfacial fractures
The diagnosis of the orbital fractures is by clinical examination, radiological examination and evaluation of vision and orbit. The goal of clinical and radiological diagnosis is to help make the decision between conservative management and operative exploration.
The clinical examination involves
- A brief history of the mechanism of injury and direction of the force should be ascertained. The clinical examinations involve a systematic approach for assessing the orbits, which will further define the functional and anatomic defects associated with orbital injuries.
- The initial ophthalmologic evaluation should include periorbital examination, visual acuity, ocular motility, pupillary responses, visual fields and fundoscopic examinations.
- The eyelids and periorbital area should be inspected for oedema, ecchymosis, lacerations, ptosis, asymmetric lid drape, canalicular injury and canthal tendon disrutption.
- Extraocular movements are evaluated to rule out mechanical entrapment or paresis.
- Any diplopia in any field of gaze is noted.
- Forced duction test is carried out to determine the mechanical entrapment if any and to differentiate between the mechanical and neurological origin of the limitation of extraocular. Absence of restriction of movement has a number of implication based on the time elapsed since injury. Resistance to free movement is seen in mechanical obstruction, which is likely to be related to
- Herniation of the periobital fat.
- Incarceration and entrapment of the extrtaocular muscles.
- Impingement of bone fragments upon fat and muscle
- Fibrous tissue formation and adhesions
- Depression of the orbital roof.
- Pupillary size, shape symmetry and reaction to light are to be noted.
- The globe is evaluated for acute enopthalmus or proptosis.
- Visual fields are tested and fundoscopic examination is done to rule out internal eye injury (retinal, lens etc.).
- Tonometry measurements are made to note the intraocular pressure. Normal range is 10 to 20 mm of mercury.
- Slit lamp test is done to rule out corneal abrasion.
- Additional investigation of radiographs, CT scans and MRI scan are useful. MRI is useful in identifying the incarceration of the orbital fat into the antrum. CT and MRI are useful in identifying the amount of bone loss and also the amount of bone intact left behind for reconstructing. Orbitography with the use of radiopaque contrast medium is helpful in revealing the orbital floor defect.
Some of the early features of the injury to the integrity of the orbital floor are
- The history of the injury
- Presence of gross periorbital ecchymosis and edema
- The presence of immediate limitation of elevation of the eye.
- The existence of limited elevation of eye with intact orbital margin and paresthesia of infraorbital nerve.
- Alteration of the ocular level. Initially there is slight elevation owing to haematoma. In large defect of the orbital floor and the hematoma small there is lowering of the orbital level.
- Hanging drop appearance of the roof of the antral cavity as seen by Water’s view (PNS view) or by CT scan.
- The presence of relatively denser fragmentation of the segments of the orbital floor within the general opacification of the antrum as seen in the PNS views.
- Propotosis due to effusion of blood into and arround the extraocular muscles (associated with upward displacement of the globe). As this blood becomes absorbed and the oedema subsides, the late signs and symptoms become evident.
After an interval of 7 to 10 days the following changes may be observed.
- Restriction in movement of the eye especially in the vertical direction.
- The concomitant development of diplopia usually most evident when looking upwards and inwards.
- A slight lowering of the ocular level.
- Deepening of the supratarsal fold
- Retraction of the globe upon attempted elevation and in some cases of depression
- Narrowing of the palpebral fissure.
ISOLATED FRACTURE OF THE ORBITAL FLOOR (BLOW OUT FRACTURES)
The consequences of isolated fractures of the orbital floor were described very early on by ophthalmologists, among them lang (1989) Beer (1892) and Lederer (1902).
The sudden increase in hydraulic pressure in the orbit is the cause of this type of fracture. Reny and stricker 1969, Fujino 1974, Says forces that affect the strong bony components can lead to isolated fractures within the orbit by transmission; without the outer bony frame being fractured.
Diagnostic difficulties in blowout fractures exist. No steps defects on palpation or displacement of the bony orbital rim can be felt and routine radiograph generally does not show fractures of the thin bony lamellae of the orbital floor.
Occasionally, opacification of the maxillary or ethmoidal sinuses, or an opacity on the roof of the maxillary sinus cavity may suggest the presence of a fracture. If diplopia and impaired mobility of the globe are present, tomography is absolutely indicated. Even in the absence of opthalmologic symptoms when swelling and haematoma of the eyelids, as well as the kind of trauma, indicate the possibility of such an isolated fracture of the orbit. Only by CT can the isolated orbital fracture be diagnosed for certain and the localisation and extent of the bony injury be determined.
TREATMENT OF FRACTURES OF THE ORBIT
A classification of fractures of the orbit based on treatment is appropriate. This gives some basic guidance with regard to the indication for surgery in those injuries of the orbit, which are combined with midface fractures. In addition to possible ophthalmologic symptoms, this classification takes into consideration the type and extent of tomographic finding and the mechanism of fracture.
Classification of Orbital Fractures Based on Treatment
(1) Simple or linear fractures of the bony orbit as accompanying injuries in typical fractures.
Surgical reduction and fixation of midface fractures. The bony segments extending into the orbit are thus reduced. In the absence of ophthalmologic symptoms no surgical exploration of the orbit itself.
(2) A Comminuted fracture of the orbit (mostly) orbital floor) in conjunction with midface fractures.
- Surgical reduction and fixatrion of midface fractures
- Surgical exploration of orbital fractures . Also in absence of ophthalnological early symptoms.
(2) B. Comminuted fractures of the Orbit – in conjunction with atypical periorbital fractures.
For eg. Periorbital comminuted fractures, frontal bane fractures with fracture of the orbital roof, or circumscribed detachment of part of the inferior orbital margin.
In conjunction with surgical reduction and fixation of periorbital fractures. The neighbouring section of the orbital wall can be included and treated as well.
(3) Isolated Orbital Floor Fractures (Blow out Fracture)
(If isolated the thin bony lamellae of the medial or lateral walls are fractured)
The management of orbital floor fractures depend upon the severity and nature of fracture.
Surgical exploration depending
- On C.T. finding as for the presence of an isolated comminuted defect fracture of the orbital wall
- If there persistent diplopia.
The objectives of surgical exploration are to
- Repositioning of the displaced orbital tissues.
- Reductions of fractures
- Stabilisation of the fragments.
- Restoration of the orbito antral partition
- Elimination of the interference with ocular movements.
- Preservations of orbital volume and periorbital fat.
The above surgical goal can be achieved by various surgical approaches in orbital floor injury. This is by
- Antral approach by use of packs as support and also by use of graft with antral pack.
- Reconstructing the orbital floor with autogenous or allogenous or alloplastic materials through various infraorbital approaches.
Reconstruction of the Orbit floor
This is done by the use of autogenous and allogenous transplants and also by use of alloplasts.
If injuries to the orbital walls are present as a secondary injury in midfacial fractures, and if they require exploration, the midface fractures are reduced first and fixed by osteosynthesis at the beginning of the operation.
In many midface fractures plate osteosynthesis is the procedure of choice, especially when periorbital fractures are present. Thin vitallium minicompression plate (Luhr 1979) which, because of the highly corrosion resistant cobalt, chromium, molybdenum alloy may remain in situ, So that removal is not needed. By the eccentric gliding hole principle (Luhr 1968) the plates may be kept so thin that remains inconspicuous even in difficult region with thin covering skin (Naso orbital rim, infraorbital rim).
After restoration of the orbital margin, the fractures of the orbital wall are displayed by strictly subperiosteal dissection. The prolapsed orbital soft tissue in the maxillary sinus are removed from the fracture margin with a fine periosteal elavator. Isolated bone fragments, stock in the soft tissue are removed.
In most cases a bony defect exists in fractures in the paper thin section of the orbital floor of the medial wall. For the reconstruction of the orbital wall, that is for the bridging of the such defects, many procedures have been suggested. Various alloplastic materials have been used for eg. polyethylene (Rubin 1951, Browing and Walker 1965) Teflon (Freeman 1962), Poly vinyl sponge (Henderson 1963) Silastic (Lerman and Cramer 1964 ) Dacron urethane (Leake etal 1980) aluminium oxide ceramic (Niederdell mann etal 1976) Tantalum gauze (prowler 1965) Autologus bone grants eg. iliac bone graft used by converse and smith (1970, 1977) and Maillard 1977) thin transplants from the wall of the antrum by converse and smith (1960) and by Obwegeser and Chause (1970).
Homologus transplants have found a further application today in primary reconstruction of the orbital floorlyophilized dura (Luhr 1969, 71 ) Cialit – preserved dura (Schmelzle 1978), lyophilized cargilage (obwegeser and chaused 1975) Sailer, 1974), Cialit preserved cartilage (Schmelz 1974).
Lyophilized dura is good in primary treatment of fractures of the orbital floor. It causes no increase in volum in the orbit by virtue of its minimal thickness and it heals without complication. Lyophilized dura is superior to alloplastic materials, since it is completely organized within a few weeks and reconstituted into an endogenous connective tissue layer capable of load bearing.
In small to medium defects (2cm in diameter) bridging of the defect with lyophilised dura alone is sufficient. The transplant is cut in such a way that it is applied to the intact bony surface of the orbital floor with 6-7mm overlap at the edge of the defect of all sides. The pressure of the repositioned orbital soft tissue holds the transplant in situ. Fixation with fibrin adhesive on the bony substratum may be undertaken.
In very large defects – particularly when they extend deeply into the orbital funnel – to reinforce the dural transplant, supplementary packing of the antrum is done. Though a window in its antero lateral wall the sinus is tightly packed from below to the exact level of the margin of the defect. The free end of the pack is lied out of the inferior meatus via an intra nasal antrostomy. The pack should remain in place for 14 days.
Replacing the prolapsed soft tissue in the depth of the orbital funnel through the infraorbital incision alone is unsatisfactory because of limited visibility and damage the optic nerve. Replacement in the dorsal region of the orbit is more safely achieved transantrally with the palpating finger. In further exploration of fracture of the medial orbital wall, the killian incision at the lateral bridge of the nose is preferred. After removal of the ethmoid bone cells the optic nerve can be displayed well and possible bone fragments removed.
COMPLICATION FOLLOWING ORBITO ZYGOMATIC FRACTURES
Complication of Zygomatic complex and arch fractures are uncommon. The complications consist of
- Oculocardiac reflex
- Ophthalmic complication
The most serious complication involves the eye and surrounding structures. The early systemic complication is occurrence of Oculocardiac reflex where there is reflex bradycardia. Malunion of fracture is a late complication resulting in asymmetric appearance.
The oculocardiac reflex is bradycardia following significant compression of the eye (Ascher 1908). Bradycardia caused by this reflex has already been reported following fracture of zygoma (Bainton & Lizi 1987), blowout orbit (Habal et al 1972) and maxilla (Precious & Sulsky 1990, Sorenson & Gilmore 1956).
Sinus dysfunction are caused by Cardiac abnormalities (as Hypert4ension, Myocardial infarction and Arteriosclerosis), Infection (Rheumatic fever), Congenital anomalies of the conducting system, Drugs (Digitalis), Electrolyte abnormalities, Respiratory abnormalities (anaesthesia & Suffocation) and Ageing.
The oculocardiac reflex is known as phenomenon that is associated with the facial area during cardiac abnormalities. This mechanism is thought to be inhibition of the heart rate by reflex excitation of the vagus nerve following stimulation of the trigeminal nerve by compression of the eye.
Clinically Aschner 1908 used it for eye compression test and Bailey 1935, Dewar & Wishart 1976, Kato & Hara 1978, Störtebecker 1953 used this as treatment for tachycardia. Barré 1921 observed development of bradycardia after experimental application of 500g or more pressure to the eye. This reverted to normal within 20s after release of the compression. Bradycardia have been reported following contusion of the eye (Habal et al 1972, Störtebecker 1953), operation for strabismus (Alexander 1975, Dewar & Wishart 1976, Sorenson & Gilmore 1956), compression after eneculeation (Bailey 1935) and orbital hematomas (, Sorenson & Gilmore 1956).
Bradycardia similar to Oculocardiac reflex have been reported following maxillofacial surgery.
Bainton & Lizi 1987 reported a case of bradycardia following reduction of zygoma through Gillies’ approach. The bradycardia was managed with intravenous atropine.
Robideaux 1978 noted bradycardia for 20s after reduction of maxillary fracture using Rowe’s disimpaction forceps.
Percious & Skulsky 1990 observed development of bradycardia and their recovery after 1 –2 min in six patients treated by Le Fort I Osteotomy and two patients treated for ankylosis.
Percious & Skulsky 1990 suggested the following mechanism for the development of the oculocardiac reflex induced by osteotomy of the midfacial bones. Sensation of the cheek is controlled by terminal branches of trigeminal nerve (Zygomatic branch and temporal branch). Following fracture/ fracture reduction / osteotomy of the zygomatic or maxillary area afferent impulses are conducted from peripheral sensory branches via maxillary and mandibular nerves to the nucleus of the trigeminal nerve. When excessive pressure impulses are transmitted, the efferent pathway of the vagus running along side is stimulated. This increases the tonus in the parasympathetic nerve resulting in bradycardia. Hamlin & Smith 1968 demonstrated the termination of vagus nerve in SA and AV nodes, suggesting the induction of bradycardia such as AV block by Vagus stimulation.
The bradycardia can be managed by means of intravenous atropine.
May occur as a result of the initial injury, operative trauma of corneal or conjunctival designation. The Patient complains of scratchy feeling. If corneal abrasion is identified, instil topical antibiotics and apply eye patch and consult an ophthalmologist.
This consist of early orbital injuries which consist of loss of vision as a result of optic nerve compression, central retinal artery occlusion, retrobulbar haemorrhage, superior orbital fissure syndrome, orbital apex syndrome, cavernous sinus syndrome.
The late orbital complications include late development of enopthalmus and diplopia, ectropion, entropion, medial canthal and lacrimal apparatus injury, lateral canthus injury and eyelid injury.
Disruption of the retinal circulation may lead to irreversible ischaemia and permanent blindness. The patient may complain of visual changes or increased pressure in the eye.
Ord in a review of 1450 zygomatic complex fractures, reported 0.3% incidence of postoperative retrobulbar haemorrhage with visual cells. An emergency ophthalmology consultation is necessary.
Superior Orbital fissure syndrome and orbital apex syndrome
This rare complication is the result of compression of the structures within the superior orbital fissure. Trauma and neoplasm are two most common causes. Ophthalmoplegia is due to palsy of cranial nerves III, IV and VII. Pupillary light reflexes may be abnormal and the first division of trigeminal nerve may be affected, producing decreased sensation of the forehead and loss of corneal reflex. Neurological and ophthalmological consultation are necessary. Treatment is generally by observation, and the problems may take up to one year to resolve.
Trauma to the eye may lead to bleeding into the anterior chamber, the area between the clear cornea and the coloured iris. In ophthalmologist should be consulted. Initial treatment consists of a combination of bed rest, use of cylloplegic agent and eye shield protection.
Other eye injuries like lens dislocation, ruptured globe, retinal detachment and canalicular injuries can also occur.
The incidence of sensory alteration of the infraorbital nerve following zygomatic trauma ranges from 18 to 56 %. Entrapment of nerve or perineural fibrosis is responsible for persistent defects.
Exploration of the orbital floor through an extra oral approach should be done to remove any bone spicules or to decompress the nerve.
May be a noticeable and debilitating consequence of Zygoma fractures. Treatment is difficult and the results are poor. As many as 80% of treated patients have persistence of exophthalmos. Better results are achieved with early reduction of fractures of the orbit and zygomatic complex.
This is seen as a result of scarring of the subciliary region of the eye following surgical treatment to repair the orbital floor region. This results in increased visibility of the sclera. This can be reduced by putting a stepped incision in the subciliary region.
This is a complication associated with trans-conjunctival approach to the orbital floor. This is also as a result of scarring.
Binocular diplopia is one of the common complications of zygomatic complex fractures and in fractures involving the orbital wall. A minor degree of alteration in the visual axis can be compensated by an addittional input of neurovascular activity but beyond a certain point, this will be ineffective in correcting the visual axis of the affected eye.
Putterman et al in 1974 postulated the limited ocular mobility that follows a blow out fracture as due to
- Fat entrapment as opposed to muscle entrapment
The three basic mechanism of persistent binocular diplopia following trauma are
- Muscle / fat entrapment in a fracture line.
- Bony displacement resulting in alteration of origin of the muscle
- Creations of adhesions between periosteal muscle or fat and the fractured bony margin.
Orbital oedema and hematoma are common and often result in diplopia, particularly in peripheral fields of gaze, which usually resolves in 7 to 10 days.
Diplopia is present when there is displaced fracture zygoma above the level of the frontozygomatic suture. A displaced fracture below the level of the whitnall’s tubercle does not predictably result in diplopia unless the supensory ligaments are disrupted.
Herniation of the orbital fat into the maxillary sinus can cause restriction of the affected globe in the primary upward and lateral gaze, resulting in diplopia in that quadrant.
Causes of diplopia following trauma are due to
- Physical interference
- Physiological interference
- Neurological deficit
The physiological deficit might be due to
- Extravasation of blood into and around the extraocular muscles.
- Impingement of extraocular muscles by bone fragments.
- Displacement of the bony origin of the muscle.
- Avulsion from the bony origin including displacement of the pulley of the superior oblique muscle.
- Entrapment of the muscle within the fracture line.
- Formation of the fibrous adhesions between the muscle sheath, periorbital fat and the margins of the defect.
This is due to muscles acting at a mechanical disadvantage following displacement of the globe.
This might be due to
- Supra-nuclear lesions
- Nuclear lesions
- Infra nuclear and intra cranial lesions
- Cavernous sinus compression
- Superior orbital fissure syndrome
- Intra orbital damage to cranial nerves.
Treatment of Long Term effects of Orbital Fractures
The late sequel of orbital fractures include depression of the globe, immobility of the globe, diplopia, and enophthalmos. Such problems can arise if an orbital fracture is overlooked as in polytraumatized patients with life threatening injuries. Considerable deformity of the bony orbit and globe results in functional and esthetic handicaps.
The displacement of the globe has serious consequences, such as diplopia in the principal direction of gaze and can lead to total disablement.
Reconstruction plastic procedure to correct such displacement may involve the use of autologus, homologus and alloplastic materials in the form of grafts or implants to elevate the globe, that is to compensate for the defects by placing some space occupying body within the orbit.
Aichmair and Fries (1971) reported good results in the correction of enophthalmos by cartilage implants with measurements of the volume of the transplant (1mm enophthalmos requires 0.5ml transplant volume). For successful correction of displacement of the globe, the shape and the placement of the transplant in the orbit are additional decisive factors that can not be calculated exactly (Luhr 1977).
Definitive correction with autologus rib cartilage or several layers of lyophilised dura are used in cases where slight depression of the globe up to 5mm and with no significant lateral displacement of the visual axis.
In very marked global depression (in excess of 3mm) with considerable deviation of the visual access and diplopia usually a two-stage correction is done. This type of defect is seen in comminuated fractures of the orbit with loss of substance of the malunited fragments and extensive scar tissue formation within the orbit. For the first operation, an assortment of acrylic implants of various sizes and shapes are used. These ready made acrylic inserts are placed in the orbit after removal of soft tissue until a satisfactory globe position is obtained. Later the implant is exchanged for a cartilage implant, usually after 3 months or more.
The two stage operation has also become an established procedure for the late correction of the misplaced globe occuring in conjunction with asymmetries and profile disorders of the neighbouring periorbital parts of the facial skeleton, resulting from severe comminuted fractures. In the first operation, the displaced globe is corrected by temporary acrylic implants, in the second operation, the periorbita, the nose and the lateral midface region are reconstructed with cartilage grafts together with the replacement of the orbital implant by a definitive cartilage graft.
In a large number of patients followed up after autologus cartilage transplantation, the results show minimal tendency to resorption with long term maintenance of the volume of the transplants (Luhr 1976, Luhr and Neutrodt 1979). Fresh homologus grafts also are suitable (Kruger 1964) Schweuzer and Schwelzle 1976) have report good results with homologus cartilage preserved in Cisplatin. Sailer (1976, 79) used lyophilised homologus cartilage with similar success. Gibson and Davis 1953, Kole 1962 report considerable reportion with preserved grafts. According to current knowledge the long term results that is the degree of resorption – depends on the method of preservation.
As an alternative method to augmentation procedures, osteotomy (refracturing) and repositioning of the displaced parts of the skelelton have been recommended (Ding mann and Harding 1951, Gillies 1967, Converse and smith 1970, Rowe 1967) An osteotomy as a sole corrective procedure is successful only when a large part of the skeleton was originally displaced with clean fracture lines.
Great progress has been made in both the basic science and the clinical knowledge base used in orbito zygomatic fracture management and reconstruction. With this increasing complex orbital reconstructive problem are better managed. The diagnosis, treatment plan and the reconstruction have evolved to a higher level.
Several areas of progress are of note the greater appreciation of the intimate relation between the bony orbits shape and the position of the globe, application of computer technology in orbital injuries, effect of rigid internal fixation on autogenous and alloplastic graft and the use of advanced bio compatible synthetic materials in orbital reconstruction. Although this progress has great impact on treatment of orbital injuries, there are many unanswered challenges to be solved with further research in the treatment of the fragile frame of the window to the human soul.
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