Ординатура / Офтальмология / Английские материалы / Oculoplasty and Reconstructive Surgery Made Easy_Garg,Touky, Nasralla_2009
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Management of Orbital Trauma and Fractures 369
Figure 10: Cases of traumatic telecanthus. There is flattening of the nose, scar at the site of fracture. The case on the left side was associated with severe ptosis while both suffered from nasolacrimal duct obstruction
If the fracture extends to the lacrimal bone and ethmoid, traumatic telecanthus may result (Figure 10). This usually requires repositioning of the bony fragments and transnasal wiring combined with canthal Y-V plasty. If there is enough bone support Y miniplate is inserted and used for the telecanthus repair.
If dacryostenosis is present, dacryocystorhinostomy may be required. Nasal bone fractures should be repaired by otolaryngeologist or plastic surgery. If associated with fracture floor, the floor should be repaired first with the implant the usually forms a platform for the medial wall implant
Transnasal Wiring: Surgical Technique
A. If the contralateral nasal bone is intact
Under general anethesia, a vertical incision is made nasal to the medial canthus. This may take a V-Y or C- U configuration if skin muscle advancement is also required in the reconstruction. The incision is carried to the fracture site adjacent to medial canthal tendon avoiding the lacrimal drainage system. The splayed bone at the posterior lacrimal crest is thinned using cutting burr. Either a 2-0 supramid suture or 27 gauge stainless steel wire is used to engage the superficial head of the tendon. If insufficient tendon remains, the supramid or wire may be positioned in the medial portion of the upper and lower tarsi.
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On the intact side, a 15 mm vertical incision is made into the skin and subcutaneous tissues just anterior to the insertion of the superficial head of the medial canthal tendon. The periostium is opened vertically at the anterior lacrimal crest and reflected anteriorly. A 5 mm opening is made by a drill through the bone and nasal mucosa anterior to the attachment.
A Wright needle or 16 gauge trocar is passed from the surgically drilled opening (normal side) through the nasal septum, emerging at the fracture site. Some pressure is needed to penetrate the septum. Care should be taken to prevent momentum from carrying the needle immediately through the fracture site with the possibility of globe injury which lie in close proximity to the medial wall. Malleable retractors are placed to protect the globe
The supramid or wire suture are placed within the eyelet of the Wright needle or within the trocar after removing the stylet and this material becomes properly positioned as the needle/torcar is withdrawn. The two ends are tightened around 8mm metal bloster pin on the sound side and the traumatized canthus is quantitatively drawn medially as the supramid or wire is secured.
The deeper layers are closed with 5-0 Vicryl mattress suture, followed by skin closure with running 7-0 silk suture.If nasal pads are to be placed, this should be done before the trocar is removed. A second loop of wire is passed through the trocar after the transnasal wiring is completed but before the skin closure, the loop is cut leaving two free skin wires. The end of each is passed through one of two silicone pads. The wires from each side are twisted together over a dental roll to compress the skin in the canthal region. The nose pads and the skin sutures are left in place for 7-10 days, then the skin wires and pads are removed.
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B. If bilateral naso-orbital fractures
If bilateral naso-orbital fractures, the bone may be insufficient on either side to support the reconstruction. In this condition, standard transnasal wiring technique takes place where two medial canthal incisions are made; bone penetration should be done at the posterior lacrimal crest level leaving intact bone anterior to this site to avoid forwards migration of the wire.
The trocar is passed and two looped 32 gauge stainless steel wires are passed; one loop with the ends of the other are tagged with the hemostat and they will become the skin wires, the other fixates the canthal tendons bilaterally. The medial canthal tendon is secured to the loop by 4-0 nonabsorbable suture. The two ends of the wire are twisted on themselves forming a second loop that is also secured to the medial canthal tendon on this side. The looped wire is tightened pulling the medial canthal angles towards the nasal septum. The skin wires are tied over nose pads to restore the concavity of tissues at the medial canthal area and removed in a similar time to the above.
C. Lateral wall fractures
The orbital plate of the zygoma is less able to absorb the trauma impact. It often fractures with orbital fat herniation into the temporal or malar regions. Lateral wall fractures are usually associated with fractures of the zygoma and corrected with replacement of the zygoma. Large defects usually need split cranial grafts with semi rigid fixation to the orbital rim.
D. Trimalar (Tripod/ Tripartite) fractures
It results form a lateral blow to the cheek resulting in a fracture of the zygomatic bone. Most commonly, the zygoma is fractured at its sutural junction with the frontal bone superiorly, the zygomatic arch laterally and maxilla medially. This can happen in different combinations. Trimalar fractures
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Figure 11: Axial scans showing varieties of zygoma complete fractures
may present with bone fragments either displaced or properly positioned. Non displaced zygoma fractures do not require surgery.
In cases of completely displaced fracture (Figure 11), the bone fragment may be displaced posteriorly. This causes a step like deformity of the infraorbital rim at the zygomaticomaxillary suture, a flattened malar process and depression of the zygomaticofrontal suture superior to the lateral canthus. Hypothesia over the infraorbital nerve distribution is a common association. Difficulty to open the mouth can be present due to displaced fragment impinging on the temporalis muscle yet extraocular muscle imbalance is usually absent.
The incompletely displaced zygoma is hinged either at the frontal or maxillary attachment. If hinged to the frontal bone, there is usually no canthal displacement as the lateral canthal tendon and Lockwood ligament are still attached to the lateral orbital tuberculum. The main displacement is at the zygomaticomaxillary suture causing lower lid retraction inferolaterally and increased scleral show while the globe remains in its place. There is a step deformity at the inferior orbital rim and inferior rectus may be entrapped in the fracture site resulting in diplopia.
Management of Orbital Trauma and Fractures 373
If the zygoma is hinged at the maxilla, the lateral tubercle is usually displaced inferiorly associated with outer canthus and globe displacement. There is a palpable gap in the lateral orbital wall. Sometimes the lateral orbital rim becomes displaced superiorly and posteriorly causing malar flattening associated with a bulge in the lateral orbital rim and the lateral canthal angle may be displaced superiorly. In either condition, there is no step deformity of the inferior orbital rim nor diplopia as there is no muscle entrapment.
Management: The fracture is reduced under general anesthesia and fixed in its place.
Surgical technique:
a. Closed reduction: that can be either done by:
•Towel clip that grasps the central portion of the fractured bone, elevating it into position until the fragment is felt to “pop” into place.
•An intraoral buccal sulcus incision where a blunt instrument is placed beneath the zygoma then upward and outward pressure is applied to restore the bone in place
(Figure 12).
•Gillis approach which is commonly used (Figure 13). A 4 cm incision is placed at the temporal fossa hairline and carried down through the temporalis fascia and muscle to the periostium. A periosteal elevator is inserted beneath the temporalis fascia and gently passed downwards till a
point below the zygoma. Leverage is applied to the elevator in an upward and outward direction reducing the fracture. The fragment can be guided by the surgeon’s other hand. In fresh fractures, the zygomatic bone once in place, it usually maintains its position. The temporalis fascia is closed with 4-0 vicryl while the subcutaneous layer is approximated by 5-0 vicryl in vertical mattress. The skin is finally closed by
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Figure 12: Lateral view for |
Figure 13: Gillis approach |
intraoral buccal approach |
|
6-0 silk sutures. If the zygoma is unstable, open and direct interosseus wiring is done.
b. Open reduction: A superolateral eye brow incision and a horizontal incision directly over the inferior orbital rim fracture site are fashioned. Dissection is carried to the fracture sites then a periosteal elevator is inserted via the inferior incision and the zygoma is rotated up into its position. All tissues entrapped within the fracture line should be released.
Specially designed miniplates and microplates are used to approximate the fractured bones. Small drill holes are placed on each side of the fractured zygomaticofrontral and zygmoaticomaxillary sutures while protecting orbital structures during drilling. The screws are advanced until the head is firmly supporting the plate.
Other methods of fixation include intramaxillary inflatable balloon and direct interosseus wiring where the bone fragments are united by 27 gauge wire that is tightened by wire twister without excessive tightening. It is effective in relatively stable fractures. The wire ends are cut leaving nearly
Management of Orbital Trauma and Fractures 375
5 mm long and reposited in a drill hole or pressed flat against the bone to avoid injury to overlying structure.
If sufficient periostium remains, it should be closed by 5-0 interrupted vicryl sutures. Muscles and subcutaneous layers are also closed with 5-0 vicryl. Skin is closed by 6-0 silk sutures (Figures 14).
If the malar flattening persists after reduction which usually occurs with comminuted fractures, the malar eminence can be augmented by alloplast or bone graft placed in a subperiosteal pocket via inferior fornix or Caldwell-Luc incision.
E. Le Fort Fractures (Figure 15)
Le Fort fractures involve the maxilla and are usually complex, asymmetric and incomplete. Pure Le Fort fractures are uncommon. Le Fort I is a low transverse maxillary fracture that does not extend to the orbit. The fragment of the maxilla containing the teeth is separated from the remainder of the facial bones. In severe cases, it may be free floating.
Le Fort II fractures are pyramidal, involving the maxilla, nasal bone and medial orbital floor. This fracture begins at the lower portion on the nasal bones, across the naso-orbital margin above the nasolacrimal canal through the medial orbital floor (sometimes associated with blow-out fracture) over the infraorbital rim through the inferior orbital canal involving the anterior and posterior walls of the maxillary sinus. This fracture crosses the posterior pillar of the upper jaw, the pyramidal and pterygoid processes, and pterygomandibular fissure ending at the medial orbital margin and lateral wall of the nose. This fracture may be partially displaced or free floating.
Le Fort III fractures create a craniofacial dysjunction involving both orbits, separating the maxilla from the skull; the facial skeleton is free floating attached to the cranium by
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Figure 14: Incision and wiring in open reduction
Figure 15: Le Fort fractures I, II and III respectively from left to right
only soft tissue. This fracture extends from the upper portion of the nasal bone, across the orbital margin near the frontomaxillary suture through the ethmoid bone passing posteriorly and inferiorly below the optic foramina to the inferior orbital fissure. It then separates into two segments; one extends upwards along the zygomaticosphenoid suture between the orbital roof and the lateral orbital wall crossing the lateral orbital rim at the zygomaticofrontal suture. The second portion extends inferiorly and posteriorly crossing the pterygoid process. The zygomatic arch is also involved.
Management of Orbital Trauma and Fractures 377
Le Fort II and III may extend to the orbital apex affecting the optic nerve and reducing vision. Management of theses fractures require open reduction usually with arch bars. They may be associated with skull fracture thus requiring conjoint work with neurosurgery.
F. Orbital Roof Fractures (Figure 16)
Isolated roof fractures are uncommon due to the strength of the superior orbital rim. They can be seen with wounds inflicted by sharp objects, gun shots or in association with Le Fort III fractures.
It may be associated with brow and eyelid ecchymosis, foreheadhypoesthesia,ptosisanddiplopia.Thelatterissecondary to superior rectus or oblique affection as well as damage to the trochlea. Ptosis results from third nerve affection, direct muscle injury or muscle entrapment. The fracture may extend to the superior orbital fissure and optic canal with resultant damage to the optic, oculomotor, trochlear and abducent nerves.Inrareoccasionswithlargeordepressedfractureitmay present with globe displacement, secondary menigeocele or encephalocele with and pulsatile proptosis.
Superior orbital rim, frontal sinus and glabellar fractures either remain extracranial or communicate with the
Figure 16: Coronal scan showing fracture roof of the orbit
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intracranial compartment. If air is detected in the anterior cranial fossa in case of orbital roof fracture, this signifies a dural tear. Unless a significant displacement is found, superior orbital rim fractures don’t need surgical reduction, displaced fractures of small size without involving the orbital roof and did not violate the intracranial space can be repositioned and wired under the microscope. All other superior rim or roof fractures should be evaluated and managed by a neurosurgeon.
G. Orbital blow-in fractures
Any of the four walls may be fractured and displaced towards the center reducing the orbital volume and causing edema, proptosis and optic nerve compression either directly or by secondary increase of intraorbital pressure. Diplopia and mechanical restriction of extraocular muscle movements as well as globe injuries can also be detected. The most common in fractured walls are the roof and the lateral wall (Figure 17). Cases with optic neuropathy or marked proptosis causing exposure should be managed as soon as possible.
Role of Endoscopy in Management of Orbital Fractures
Endoscopic repair of orbital fractures could become a predictable and efficient treatment alternative to traditional
Figure 17: Fractured zygoma incarcerated behind the intact globe