Anatomy

The anatomy of the eyelids has been discussed in detail in previous chapters. This chapter touches briefly upon the relevant surgical anatomy with reference to lid surgery.

The main functions of the eyelids are to protect the globe and to moisten and clean the ocular surface, thereby maintaining its integrity, as one of the mechanisms that helps keep the cornea transparent. Failure of lid closure (lagophthalmos) or defects in the lids may lead to exposure keratopathy, which may result in visual impairment or loss of sight due to conjunctivalization; or may cause ulceration of the cornea that can escalate to endophthalmitis. Malpositioning of the lids may be the culprit in some unpleasant and nagging symptoms such as epiphora and chronic conjunctivitis. Stability of the lids, their apposition to the globe, and a normal and regular lid closure as in a blink are decisive factors for a normal eyelid function.

From a surgical standpoint, the tarsal plate is suspended laterally and medially by the lateral and medial canthal tendons, respectively. The posterior part of the medial canthal tendon determines the apposition of the lid to the globe. Superiorly, the tarsal plate is suspended by the levator palpebrae superioris muscle to the Whitnall’s ligament and superior orbital rim. Inferiorly, the tarsal plate is anchored to the inferior orbital rim by the inferior lid-retractors (capsulopalpebral fascia). The tarsal plates are akin to the skeletal system providing stability to the lids and a smooth apposition to the globe ( ▶ Fig. 16.1) (see ▶ 1). The levator palpebrae superioris muscle and Müller’s muscle open the lids, whereas the orbicularis oculi actively aid in lid closure as does gravity passively to a certain extent.

The eyelid can be divided into posterior and anterior lamellae ( ▶ Fig. 16.2, ▶ Fig. 16.3); this surgical division is of great significance for the reconstruction of eyelid defects. The tarsus and tarsal conjunctiva constitute the posterior lamella, whereas the anterior lamella is formed by the orbicularis oculi muscle and the eyelid skin. The eyelid skin is characteristically very thin and has little subcutaneous tissue. The blood supply is from a dense network of capillaries that crisscross both in the anterior and the posterior lamellae. This is why in the reconstruction of large defects, a lamella can be replaced by a free graft.

Located at the medial canthal end are the puncta and the tear drainage system. By their normal blink mechanism the eyelids are also responsible for the drainage of tears from the lacus lacrimalis. Malposition of or trauma to the medial aspect of eyelids may result in epiphora.

Lymphatic drainage is mainly by the preauricular and submandibular lymph nodes. The former drains the lateral two-thirds of the upper lid and medial one-third of the lower lid, whereas the latter accounts for the medial one-third of the upper lid and lateral two-thirds of the lower lid. This is of significance during assessment of periocular tumor spread.

16.2 Traumatology

Lid injuries more often than not are associated with injuries to the globe and the periorbita, face, head, and neck regions. In many such patients with polytrauma, stabilizing the more life threatening injuries take precedence over ocular injuries at presentation.

16.2.1 Case History

In evaluating a trauma patient, the importance of eliciting a detailed history of the sequence of events that led to the traumatic incident cannot be overemphasized. Hammer-and-chisel injuries are, more often than not, associated with small entry wounds and intraocular or even intraorbital foreign bodies and in many cases require imaging. It must be remembered to check the adequacy of tetanus immunization in such scenarios.

Bite and claw wounds are often associated with injuries to the lacrimal drainage apparatus and particular attention is required while examining such cases. Canaliculus lacerations have to be suspected in all medial lid injuries, especially when these are associated with a lateral displacement of the lacrimal punctum. Careful probing of the canaliculi and, when necessary, their end-to-end anastamosis during wound repair is pivotal.

16.2.2 Examination

The assessment of ocular and periorbital injuries should be done in four steps:

1. 
   

   Examination of the eye.

   
   
2. 
   

   Examination of the eyelids and soft tissues.

   
   
3. 
   

   Examination of the orbit.

   
   
4. 
   

   Examination of the face. ¹

The detailed examination of the eye can be hindered by swelling or hematoma of the eyelids; also the visual acuity cannot be determined in unconscious or uncooperative patients. In some cases an examination in the operating theatre under anesthesia may be necessary.

The referring doctor can make a preliminary assessment of the eye with the aid of a torch light. If the patient experiences pain when opening the eye, one can place a drop of local anesthetic eye drops (proxymetacaine, tetracaine) into the eye so as to facilitate examination.

First, a rough assessment of visual function should be made. Each eye is examined separately for ability to read fine or large prints, count fingers, or appreciate hand movements at 30 cm distance, and in extreme cases the ability to perceive light.

The next step is to look for a relative afferent pupillary defect (RAPD). Done correctly, this is extremely sensitive in picking up early or mild optic nerve pathology (in this context, traumatic optic neuropathy [TON] or compressive optic neuropathy). As prerequisites, the patient has to fix at a distance target; the examiner must not to get in the way of the patient’s line of sight; a fairly bright pointed source of light has to be used; and the examination has to be carried out in a dark or dimly lit room. The pupils are illuminated alternately in quick succession, swinging from one pupil to the other, hence the name swinging flashlight test. Normally both the pupils contract equally regardless of which pupil is illuminated, as the direct and consensual pupillary light response are equal due to equal innervation. If illuminating one pupil elicits a dilation of both the pupils, which contract again if the fellow pupil is illuminated in turn, a relative afferent pupil defect in the first eye is to be suspected, for example, in severe globe trauma or traumatic optic neuropathy. RAPD also has prognostic significance and correlates negatively with visual prognosis after trauma. ² One method for the assessment of visual prognosis after ocular trauma is the so-called Ocular Trauma Score (OTS). ³ Details are depicted in ▶ Table 16.1 and ▶ Table 16.2. This is of significance when discussing visual prognosis with the patient and/or relatives.

Loss of pupillary shape, blood in the anterior chamber that partially or totally occludes further details, or prolapse of intraocular contents ( ▶ Fig. 16.4) are an indication of penetrating globe trauma through an injury to the cornea or sclera.

If no injury to the eye is apparent, the intraocular pressure (IOP) can be carefully assessed by the finger tension method through the closed lid. Lower IOP than in the fellow eye can indicate a concealed globe rupture; a raised IOP can indicate a secondary glaucoma.

Initially, the points assigned in ▶ Table 16.1 are summed. The total gives the score for the OTS group. Using ▶ Table 16.2, the final vision to be anticipated can be roughly assessed. For example, with a globe contusion and an initial vision of 6/10 and no further complication, in 94% cases a final vision of at least more than 6/12 can be expected. On the other hand, with a globe rupture, with initial vision of NPL and positive RAPD, 74% cases can end in permanent blindness, but in 11% cases orientation vision may be the end result. This also applies in cases of globe-saving surgeries independent of the initial vision.

When examining the lids, attention should be paid to possible malpositioning (traumatic ptosis with disinsertion of the levator aponeurosis) or loss of the angulation in the lateral and/or medial aspect (indicates an avulsion of the lateral/medial or both suspensory ligaments). Measuring the levator function can be helpful as well.

A prolapse of orbital fat tissue indicates a defect in the orbital septum and possibly an injury to deeper-lying structures. Repair entails careful exposure, with understanding of the anatomy so as to restore viable tissues in their anatomically correct location.

Examination of the orbit is dealt in detail in Chapter ▶ 3 and ▶ 8.

A superinfected wound needs a course of systemic antibiotics, oral or intravenous according to the severity of the infection.

16.2.3 Diagnostic Measures

The primary imaging modalities when an intraorbital or intraocular foreign body is suspected are conventional radiography, computed tomography (CT), and ultrasound. Magnetic resonance imaging (MRI) should not be used under any circumstances in which a metallic foreign body is suspected. Not only is CT scan (ideally spiral-CT) the most sensitive method for pin-pointing a foreign body but it is also very specific in localizing it and hence should be the method of choice when a foreign body is suspected ( ▶ Fig. 16.5). Additionally, bony structures are well discernible and fractures better localized.

If the globe is intact, sonography (specifically B-mode) should also be used because intraocular foreign bodies can be clearly defined and their exact location better pin-pointed by the B-mode scan.

16.2.4 Surgical Treatment of Lid Injuries

Lateral Canthotomy and Inferior Cantholysis

Before elaborating on the specific surgical protocols of various aspects of lid injuries, a brief note on the method of relieving acute increase in intraorbital pressure (e.g., intraorbital hemorrhage) is worthwhile. Lateral canthotomy, alone or in severe cases along with an inferior cantholysis, is a quick and easy means of relieving acute increase in intraorbital pressure. These procedures act by decompressing the orbit anteriorly.

The indication, as described above, is sudden and rapid increase in intraorbital pressure that causes compressive optic neuropathy and vision loss. These procedures can be carried out in an emergency setting at the bedside. After local infiltration anesthesia with lidocaine 2% with epinephrine 1:200,000 and topical proparacaine eye drops, a hemostat is applied horizontally on the lateral canthus into the lateral orbital rim. After a couple of minutes, the hemostat is removed and the lateral canthus is incised horizontally up to the lateral orbital rim (lateral canthotomy) with straight scissors. Now the lateral aspect of the lower lid is held with toothed forceps and the inferior band of the lateral canthal tendon of the lower lid is incised along with the lateral insertion of the orbital septum (inferior cantholysis). The wound is left open to decompress the orbit and can be re-sutured at a later date.

Basic Concepts in the Management of Eyelid Trauma

Lid injuries are sometimes associated with globe injuries. ⁴ A globe injury naturally takes precedence over a lid injury. Surgery in cases of globe perforation is generally carried out under general anesthesia as periocular infiltration with a local anesthetic can lead to a rise in orbital pressure, which can lead to a prolapse or loss of intraocular tissues.

Periocular hematomas are, as a rule, treated conservatively with measures to reduce the swelling such as cold compresses and NSAIDs in case of pain. Only when encapsulation and liquefaction of the hematoma has taken place should this be surgically removed in order to avert superinfection ( ▶ Fig. 16.6).

When inspecting the wound the extent and location of the wound, involvement of the lid margins and tarsus, injury to the canthal tendons and to the tear ducts and potential loss of tissue, contamination, or foreign bodies are important considerations. Most lid injuries can be treated under local anesthetic in cooperative patients. Regional anesthesia is indicated with extensive injuries. On the upper lid the frontolacrimal block anesthetizes the entire lid apart from the medial part. The supratrochlear block anesthetizes the medial aspect of upper lid. The lower lid can be anesthetized with the infraorbital block. Additionally, local infiltration with lidocaine 2% or mixed with bupivacaine 0.5% plus epinephrine 1:200,000 up to 1:100,000 is used when needed. First, a thorough wound cleansing is done with normal saline, or where needed with diluted povidone iodine solution, and inspected for foreign bodies. All foreign bodies are to be carefully removed as they can lead to chronic infections, inflammations, or toxic reactions. The wound should be irrigated continuously under pressure ⁵ using an irrigating cannula. Due to the excellent blood supply, débridement of devitalized tissue is rarely necessary as these often heal excellently. For this reason only confirmed necrotic tissue should be debrided. The surgical correction of eyelid trauma should not only restore the integrity and protective functions of the lids but also, to the extent possible, deliver a cosmetically acceptable result. For this the following components of the eyelids have to be reconstructed:

• 
  

  Anterior lamella (skin and orbicularis).

  
  
• 
  

  Posterior lamella (tarsus and conjunctiva).

  
  
• 
  

  Canthal tendons.

  
  
• 
  

  Canaliculi.

  
  
• 
  

  Levator complex. ¹

The canthal tendons, the lacrimal drainage apparatus, and the levator are treated first.

Surgical Correction of the Canthal Tendons Tears

When operating on the canthal tendons it is important that the directional vector of the canthal tendons pull inwards so that the lids lie apposed to the convexity of the globe. The lateral canthal tendon is sutured to the periosteum of the lateral orbital rim with a nonresorbable 5–0 suture (e.g., 5–0 polypropylene). When the canthal tendon is lost, it can be replaced by a periosteal flap from the lateral orbital rim.

The medial canthal tendon consists mainly of two parts that circumscribe the lacrimal sac. The posterior part, which is attached to the posterior lacrimal crest, is responsible for the stability and directional vector of the medial canthus. The canthal tendons must be re-attached by suturing them onto the periosteum of the posterior lacrimal crest so as to achieve an apposition of the lid to the globe. If the periosteum is not intact, then a T-shaped titanium plate is sutured posteriorly to the nasal bone in order to achieve a posterior vector. Where fractures are more extensive, multiple plates and possibly even transnasal wiring may be necessary. ⁶

Surgical Correction of Lacrimal Pathway Injuries

With injuries to the lacrimal pathway, reconstruction is necessary with silicone intubation. First, the lacrimal puncta is identified and then carefully dilated with a Nettleship dilator. Under the microscope or a loupe, the medial end of the severed canaliculus can be identified as a white ring. If this cannot be done, then it is possible to inject air into the opposite canaliculus, when it is intact. Once the lacerated end is found, it is intubated with a silicone tube. For this purpose the Mini Monoka (FCI Ophthalmics) is particularly suitable; this is a short tube that can be simply inserted into the canaliculus and that coils itself up in the lacrimal sac, ( ▶ Fig. 16.7). It sits firmly in the punctum due to a knob at the proximal end. Intubation all the way into the nose (see Chapter ▶ 15.1) under local anesthesia is very unpleasant for the patient.

Another possibility is ring intubation using a pigtail probe. However, the healthy canaliculus must likewise be probed for this.

The pericanalicular tissues are adapted with 6–0 absorbable sutures and finally the skin is adapted directly taking care that there is not much tension, lest cheese-wiring and wound dehiscence may occur.

Surgical Correction of Injuries to the Levator

A traumatic ptosis points to a laceration of the levator palpebrae superioris muscle. In such cases, the torn ends of the muscle need to be identified and sutured with 6–0 absorbable sutures or the distal end of the muscle is sutured to the tarsal plate. The orbital septum is generally not sutured.

Surgical Correction of Lid Margin Tears

Blunt traumas can surprisingly result in considerable injuries to the lid margins and the tarsus. Often, the full extent of the injury is not visible upon casual examination and is only determined upon closer examination, sometimes under local anesthesia ( ▶ Fig. 16.8).

There are several methods of treating lid margin tears. The principle behind all of them is end-to-end adaptation of the posterior edge of the lid margin, meibomian gland orifices, gray line, and eyelash line in an anatomically correct way. In the author’s (M. A. Varde) own experience the adaptation of the edges of the eyelid with an oblique absorbable suture is simpler than suturing with silk and produces reproducibly good results ( ▶ Fig. 16.9). Here the eversion of the edges of the wound is important as they draw inward due to the contraction of the wound and can thus result in a groove. In some instances there is only a small lid margin defect and, upon everting the tarsus, a tarsal fracture running its entire height is revealed so that the wound needs to be extended superiorly for it to be sutured with 6–0 absorbable sutures. Partial thickness sutures are placed anteriorly through the tarsal plate and knotted on the anterior surface so that the tarsal conjunctiva is free of irregularities. Full-thickness sutures on the upper lid are to be avoided as they will produce painful corneal erosions and in some cases lead to corneal ulcers.

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