Ординатура / Офтальмология / Английские материалы / Oculoplasty and Reconstructive Surgery Made Easy_Garg,Touky, Nasralla_2009
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Acquired Lacrimal Obstruction 149
Figure 13: The Medpor coated glass tube is an alternative to the traditional Jones tube
Figure 14: Scleral necrosis prompting removal of the Jones tube
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Figure 15: The Kelly glaucoma punch could be used to cut–open stenosed puncti
including the inability to create flaps that could be sutured to create primary intention healing, plus the poor access to the superior bone opposite the fundus of the sac which still places endonasal techniques as a second choice after the external route (Figures 6 to 15).
Surgery in Special Situations
In case of isolated punctal stenosis, a DCR is not needed. Dilatation of the punctum plus stenting with a perforated plug, a monocanalicular tube or pigtail probing is enough. In case of complete punctal and canalicular fibrosis, a lacrimal bypass tube, the Jones pyrex tube, or one of its newer alternatives may be needed.
PROGNOSIS
External DCR has a success rate of over 90% in expert hands. Canalicular obstruction has a much lower rate of success even with successful intubation. If functional success (relief of symptoms) does not coincide with anatomic success (patency on syringing), then the lacrimal pump function should be reevaluated.
INTRODUCTION
Lacrimal injuries are usually not isolated. They are almost always associated with lid injuries or orbital or nasal fractures. Eyelid, orbital and adnexal injuries can be a part of multisystem trauma. The basic ABCs of the trauma management should be considered and once the patient is stable, it is possible to properly examine the eyelid with the upper lacrimal passages, orbital injuries as well as the associated globe or optic nerve affection. It should be remembered that upper lacrimal drainage system can be involved in chemical or thermal injuries
EVALUATION OF LACRIMAL INJURIES
History
The conditions of trauma can give an idea about the nature and the extent of injury. Being usually associated with lid or orbital injuries, high index of suspicion should exist to be able to detect lacrimal passage injuries. Lacrimal gland injury is usually rare and may be associated with orbital roof fractures or deep upper lid wound.
Review of medical history is essential as well as drug allergy history of tetanus immunization and problems encountered with anesthesia.
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Examination
Routine systematic examination of the eyelid, globe and orbit should be performed. Canalicular injury is suspected when the injury lies medial to the punctum which is usually laterally displaced compared to the other side or the opposite one. Medial or lateral canthal injuries as well as tissue loss should be ruled out.
Lacrimal passage injuries associated with orbital or nasal fractures may be overlooked especially with the edema or ecchymosis. However, associated nasal bone fractures as well as traumatic telecanthus should raise the index of suspicion.
In case of late presentation of lacrimal drainage system injuries, systematic evaluation should be adopted. This includes, evaluation of the conjunctiva for presence of adhesions as well as assessment of the punctal position, direction and patency. Positive regurge test is a sure sign of nasolacrimal duct obstruction. Dye disappearance test show delay as compared to the other side. Probing may show strictures of the canaliculi or fibrosis of the lacrimal sac that usually felt as a soft stop. Irrigation test can show the extent of NLD obstruction. Nasal examination is very important is such cases as a deviated septum resulting from the original trauma may be the reason of the lacrimal passage problems.
Orbital CT whither conventional cuts or in three dimensions can show the fractures sites and their extent as well as associated nasal deformities.. Dacryocystography can show nasolacrimal duct obstructions site and extent.
PROPER LACRIMAL SYSTEM
Proper lacrimal system evaluation is necessary for choosing the treatment protocol.
Lacrimal Injuries 153
Wounds Associated with Canalicular Injuries
They can result from direct trauma to medial canthal area or indirectly by avulsive forces caused by trauma to the orbit. They are common with dog bites and midface injuries. Early repair of the canalicular injury is much easier and more successful than late repair or conjunctivodacryocystorhinostomy with Jone’s tube.
Canalicular lesions may be missed. They should be suspected in injuries medial to the punctum that may be and may be laterally displacement. The diagnosis is confirmed by direct visualization of the cut edge or passing a probe into the canaliculus.
Repair of canalicular injuries is done under general anesthesia. A stent should be placed through the transected canaliculus. Bicanalicular silicone tube is commonly used however, some surgeons use monocanalicular tubes. In case of bicanalicular tube use, the severed canaliculus is intubated first. Both are retrieved from the nose. The marginal wound is then repaired and canthal tendon wound is also repaired before tying the silastic tube (Figure 1). After the wound is approximated, the tube is secured by three square knots and left in place for 6 months (Figures 2A and B).
The medial cut end of the canaliculs could be identified under the microscope with high magnification. It can also be identified using injection of a fluorescein dye or viscoelastic material into the sac through the intact canaliculus. Pooling saline in the medial canthal area with injecting air into the intact canaliculus will point at the site of cut canaliculus where the air bubbles. If the wound is ragged freshening of the edges may be helpful. Retrograde intubation using Pigtail probes is better avoided as it can cause a false passage.
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Figure 1: A diagram showing lower canalicular injury with a bicanalicular tube inserted first before the repair of the marginal wound
If the punctum is lacerated, the medial canaliculus could be marsupialized or opened to the conjunctival sac and the lid wound is repaired ignoring the injured punctum and canaliculus.
Lacrimal Sac and Nasolacrimal Duct Injuries
These lesions may be missed as these parts are included in a protective bony structure. A high index of suspicion should be present to anticipate these problems. They are usually associated with nasoethmoidal fractures, sometimes with blow out fractures of the orbit and types II and III Le Fort fractures.
A nasoethmoidal fracture usually results from a force delivered across the nasal bridge and it’s very common in automobile accidents in which the face strikes the dashboard.
Lacrimal Injuries 155
Figure 2: Left shows lower lid marginal wound involving the lower canaliculus. Right photo shows it after inserting the tube and repair of the wound
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The nasal bones become fractured and displaced. The lacrimal and sphenoidal bones are usually crushed. They are associated with surgical emphysema. Traumatic telecanthus is usually present in association with lacrimal passage injury.
If the fracture is detected and repaired, irrigation of the lacrimal system by the end of the repair should be done. If there is a free system irrigation, nothing more is needed to be done. If there is some minor resistance exists, probing and bicanalicular silicone intubation where the tube is left for 3-6 months may be of use.
If these fractures are not detected and corrected, chronic dacryocystitis can occur and needs dacryocystorhinostomy (DCR). It is sometimes associated with excess bone formation in the area of the nasal and lacrimal bone that accentuates the possibly present traumatic telecanthus. This bone can be debulked while performing the DCR. The surgery can be associated with repair of the present telecanthus.
Old Traumatic Lacrimal Passage Injuries
Management of such injuries varies according to the site and extent of obstruction and addressed in a similar way as non traumatic cases. For example, destruction of the upper lacrimal system especially with chemical injuries and obliteration of the canaliculi usually necessitates conjunctivodacryocystorhinostomy (CDCR) with insertion of Lister Johns tube. Chronic dacryocystitis or complete NLD obstruction are treated by conventional DCR.
INTRODUCTION
Congenital ptosis is a common entity managed by the oculoplastic surgeons. It results from a developmental dystrophy of the levator muscle of unknown etiology. Management of the condition requires a thorough understanding of the surgical anatomy and a meticulous surgical technique based on a proper evaluation.
SURGICAL ANATOMY OF THE UPPER EYELID AND EYEBROW
The thorough understanding of the surgical anatomy of eyelid is necessary to give good functional and cosmetic results.
The layer of upper eyelid from anterior to posterior are skin, subcutaneous tissue, orbicularis muscle, submuscular tissue, orbital septum and preaponeurotic pad of fat, levator aponeurosis, muller muscle, tarsal plate and conjunctiva
(Figure 1).
Skin of the upper lid is thinnest in the body. The skin is attached loosely over the eyelid, but firmly over the brow, lid margins and canthi.
Orbicularis muscle is responsible for blinking and lid closure. It originates from medial palpebral ligament and the fibers spread in elliptical fashion. It is divided in to orbital
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and palpebral portion. The palpebral portion runs from medial canthal ligament to lateral palpebral raphe.
Submuscular layer is corrected with the submuscular layer of the brow and thus the infection can spread through this plane. Most of the blood vessels and nerve lie in this area.
Orbital septum and tarsal plate – form a continuous layer of fibrous tissues and is mainly responsible for the stability of the eyelid.
Levator muscle – is the main retractor of the upper eyelid. It originates above the optic foramina under the lesser wing of sphenoid. It moves forward under the orbital roof and above the superior rectus muscle. Near the equator of the globe it is transformed in to fibrous aponeurosis, which travels forwards and inferiorly and gets inserted into the upper 2/3rd of the anterior tarsus. The other attachments of the levator aponeurosis are to skin of the upper lid after penetrating the orbicularis muscle forming the lid crease. Its medial and lateral extensions are known as ‘horns’. The lateral horn attaches to the orbital tubercle. by the canthal ligament. It is important to remember that the lateral horn separate the lacrimal gland into palpebral and orbital part. The medial horn forms the medial canthal ligament.
Muller muscle – is a thin sheet of non-striated muscle which arises near the junction of the levator and its aponeurosis from its under surface and attaches to the superior forward border of tarsus. The superior transverse ligament (Whitnall’s ligament) arises from the under surface of the levator. It assists in suspension of the levator muscle.
Conjunctiva – is inner most layer of the lid. The palpebral conjunctiva is transparent, highly vascular and is strongly attached to tarsus of upper lid. It is continuous with the bulbar conjunctiva via superior fornix.