Exposure Keratopathy Due to Facial Palsy





Darmayanti Siswoyo

Dr. Darmayanti Siswoyo is currently consultant of Ophthalmic Plastic & Reconstructive Surgery, Jakarta Eye Center Hospital, Indonesia.

She was the past Head of Ophthalmic Plastic & Reconstructive Surgery Division, Department of Ophthalmology, Faculty of Medicine, University of Indonesia.

She was also the past Head of Indonesian Ophthalmic Plastic & Reconstructive Surgery & Eye Tumor Surgery Association.

She graduated from Department of Ophthalmology University of Indonesia in 1987.

She underwent orbital reconstruction training at Cranio Facial Center, Department of Plastic surgery, Royal Adelaide Hospital, South Australia in 1987.

She also underwent Oculoplastic & Reconstructive Surgery training at Department of Plastic Surgery, Kansai Medical Faculty and Department of Ophthalmology, Hamamatsu Hospital, Japan in 1992.

She was an Observer at Moorfield Eye Hospital London, England, 1993.

She is also National Speaker, Didactic Course Instructor, Wet Lab Instructor in Oculoplastic and Reconstructive Surgery in Indonesia since 1988 and International Speaker in Oculoplastic & Reconstructive Surgery since 1996.


 




Introduction


Facial nerve palsy causes paralysis of the orbicularis oculi which results in atony of the muscle, elongation of the tarsal plate, medial and lateral canthal ligaments, and laxity of the upper and lower lid, resulting in lagophthalmos and corneal exposure and culminating in exposure keratopathy (Figs. 50.1 and 50.2).

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Fig. 50.1
Left eye facial nerve palsy with severe ectropion and corneal exposure


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Fig. 50.2
Left eye facial nerve palsy with severe ectropion and corneal exposure

Paralytic lagophthalmos denotes incomplete closure of the eyelid as a result of paralysis of the seventh cranial nerve, usually from lesions affecting the nuclear or peripheral portion of the nerve.

Facial nerve paralysis with resultant lagophthalmos and ectropion can occur from many causes, including Bell’s palsy, tumors, trauma, injury, or vascular accidents affecting the facial nerve. Whatever the cause, the ocular complications of inadequately or improperly managed facial paralysis range in severity from corneal irritation and punctate keratopathy to corneal ulceration, perforation, and blindness (Fig. 50.3).

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Fig. 50.3
Corneal perforation

The facial nerve innervates both the frontalis muscle, which raises the eyebrow, and the orbicularis oculi muscle, which closes the eyelids [1, 4, 7]. Loss of function of the facial nerve inhibits eyelid closure as well as the blink reflex and the lacrimal pumping mechanism. In addition, the facial nerve innervates the muscles of facial expression including the zygomaticus muscles, which elevate the cheeks as well as the corrugator supercilii and procerus muscles, which depress the eyebrow. These muscles play an important role in maintaining facial symmetry.


Etiology


Facial nerve palsy may result from a broad spectrum of causes largely due to its topographic complexity [7, 8].

Trauma: The facial nerve is susceptible to blunt trauma or laceration along its bony course. Fractures to the skull base or mandible can damage the nerve or one of its branches.

Cerebrovascular accidents: The facial nerve receives its blood supply from the anterior inferior cerebellar artery. It is most susceptible to ischemic damage just proximal to the geniculate ganglion.

Bell’s palsy: This is an idiopathic facial nerve palsy that is thought to be associated with an acute viral infection or reactivation of Herpes simplex virus.

Tumors: Acoustic neuromas in the cerebellopontine angle and metastatic lesions are most commonly associated with lagophthalmos.

Iatrogenic trauma after the removal of tumors.

Infectious, immune-mediated causes: Less common causes of lagophthalmos include Lyme diseases, chickenpox, mumps, polio, Guillain–Barre syndrome, leprosy, diphtheria, and botulism.

Moebius’ syndrome: This rare, congenital condition is characterized by cranial nerve palsies (especially sixth and seventh cranial palsies), motility disturbances, limb anomalies, and orofacial defects.


Medical Therapy


Medical therapy includes emollient eyedrops [3, 8], as well as taping. The tape should be passed from lateral one-third of the lower eyelid and then pulled up to the temple (Fig. 50.4) to reduce exposure of the cornea. Do not use gauze for dressing, as it will stick to the cornea and cause more severe corneal damage. Botox injection to the levator muscle can be done to induce ptosis of the upper lid [6], as well as tarsorrhaphy [2, 8] as a temporary measure for corneal protection, but sometimes this is cosmetically unacceptable to the patient. The majority of patients require definitive surgical treatment to correct this chronic impairment.

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Fig. 50.4
Taping the lower eyelid


Surgical Management (Table 50.1)





Table 50.1
System for facial nerve palsy

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Surgical intervention is primarily considered in cases in which medical management has failed or the condition is unlikely to improve over time.

In facial nerve palsy, laxity occurs in all parts of the lower lid.

When there is laxity and poor lateral canthal fixation to the lateral orbital wall, refixation of the eyelid to the lateral orbital tubercle with tarsal strip procedure corrects the laxity and restores the contour of the lateral canthal angle [9].

When the lateral canthal tendon is stable and there is marked redundancy to lower lid skin, the Byron Smith modification of the Kuhnt–Szymanowski procedure combines horizontal full-thickness eyelid shortening with a blepharoplasty – type skin incision is desirable [9].

In the author’s experience, if only the lower lid margin is shortened, without enhancement with ear cartilage graft or synthetic material, the laxity will recur again usually 6 months after surgery due to the absence of orbicularis muscle contraction.


Shortening Lower Lid Margin by Lateral Tarsal Strip Procedure Enhanced with Ear Cartilage Graft with a Blepharoplasty: Type Skin Incision


Subciliaris skin incision and then orbicularis muscle dissection to expose the inferior orbital rim, lateral canthotomy is done, and inferior cantholysis is completed to mobilize the lateral aspect of the eyelid for its advancement superiorly and laterally. The tarsal strip is made by excising the mucosa, cilia, and orbicularis at the lateral edge of the eyelid. The length of the tarsal strip to be excised is determined depending on the laxity of the eyelid. At least 4–5 mm of bare tarsal strip is left intact for attachment to the lateral orbital rim. Residual mucosa on the posterior surface of the tarsus is deepithelized (Fig. 50.30). Then harvest the graft from ear cartilage as mentioned below in (Figs. 50.22, 50.23a–d, and 50.24). Suture the graft as the same as mentioned in Fig. 50.25a and 50.25b then continue suturing the lateral tarsal strip. A 5.0 suture is passed into the periorbita 2–4 mm within the lateral orbital rim above the level of the lateral commissure; the suture is then passed through the stump of the tarsus, and then it is brought back through the tarsus. The needle is again passed into the periorbita, just above the initial periorbital bite, and then the suture is tightened. Reinforce the lateral lower eyelid tarsus and orbicularis to the periorbital with two or three additional sutures to tighten the lower lid tissues (Fig. 50.31). Redefine the lateral commissure.


Shortening Lower Lid Margin by Khunt–Szymanowski Combines Central Full: Thickness Eyelid Excision Enhanced with Ear Cartilage Graft with a Blepharoplasty-Type Skin Incision


In the author’s experience, tightening the central part of the lower lid by excision of the central lower lid tissues, and then suturing layer by layer, makes the entire lower lid structure stronger (Fig. 50.5), compared to excision of the lateral part of the lower lid tissue (Fig. 50.6).

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Fig. 50.5
Central pentagonal excision


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Fig. 50.6
Lateral pentagonal excision

A central part lower lid shortening procedure enhanced with ear cartilage graft or synthetic material fixed at the inferior tarsal plate and at the lower orbital rim will maintain a normal position of the lower lid margin (Figs. 50.7 and 50.8).

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Fig. 50.7
Central pentagonal excision


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Fig. 50.8
Ear cartilage graft

How to prevent lid margin notching:

The superior part of the excision should be shorter than the lower part (Figs. 50.5 and 50.9). To create slight eversion of the wound edges (Fig. 50.10), prevent late depression or notching of the resulting scar (Fig. 50.11).

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Fig. 50.9
To prevent lid margin notching, the superior part of the excision should be shorter than the lower part


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Fig. 50.10
Slight eversion of the wound edges

Oct 16, 2017 | Posted by in OPHTHALMOLOGY | Comments Off on Exposure Keratopathy Due to Facial Palsy

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