Blepharoplasty

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CHAPTER 30 Blepharoplasty

The eyes are often said to be the window to a person’s soul. When considering facial plastic surgery, this statement holds true. The eyes play a central role in human communication. They are capable of expressing emotions such as anger, sadness, happiness, surprise, disappointment, hatred, and love. However, it is not the globe itself, nor the color of the iris that is responsible for expressing these emotions. Rather, it is the dynamics of the periorbital region that allows us to convey our feelings through our eyes: alterations in the shape of the palpebral fissure, positioning of the brows, furrowing in the glabella, and redundancy and fullness in the lids.

The aging process affects the skin and underlying tissues by both intrinsic and extrinsic factors. Intrinsic aging refers to the effects of time on the skin. Over the course of one’s lifetime, the epidermis and subcutaneous fat layers thin and there is effacement of the dermal-epidermal junction. There are fewer Langerhans cells and melanocytes, and the morphology of the keratinocytes changes. There is a progressive loss of organization of elastic fibers and collagen (elastosis), and a weakening of underlying muscles. Extrinsic factors such as gravity, smoking, and sun exposure may result in keratinocytic dysplasia and accumulation of solar elastosis. Taken together, the intrinsic and extrinsic aging processes create pigmentary changes, rhytids, and texture irregularities of the skin (Fig. 30-1).1,2

On a macroscopic level, aging results in brow ptosis, lateral brow hooding, crow’s feet, fine and deep rhytids, and loss of elasticity. Even though the effects of aging are normal, ubiquitous, and acceptable to many individuals, others find such changes to be an area of concern. In the periorbital region, the effects of aging may cause an individual to unintentionally convey external expressions of boredom, fatigue, and sadness, even though these are not the emotion being felt (Fig. 30-2). Because the eyes convey emotions, aging of the upper third of the face is almost always more visible and of greater impact than aging of the lower face and neck. To fully address the periorbital region surgically, it is first essential to understand its anatomy and aesthetic ideals.3

Anatomy

Orbital Anatomy

The orbits are pyramidal bony structures composed of seven different bones: the frontal, maxillary, sphenoid, zygomatic, ethmoid, palatine, and lacrimal. Each orbit is 30 cm2 in volume, and lies 25 mm from the other. The entrance of the orbit is 40 mm in height and 35 mm in width, and the widest part of the orbit lies 1 cm posterior to the anterior orbital margin. The orbital periosteum, the periorbita, is firmly adherent to the bone, especially at the suture lines between the seven constituent bones of the orbit. The lacrimal gland fossa, located in the anterior-superior-lateral aspect of the orbit, houses the lacrimal gland. The supraorbital nerve and artery are transmitted through a true foramen in 25% of cases and through a notch in most cases. The frontal sinus lies superior to the orbits, and the ethmoid sinuses lie medial to the orbits.

The lateral orbital wall is formed by the greater wing of the sphenoid and zygoma and is 47 mm long. The lateral orbital tubercle (Whitnall’s tubercle) is 10 mm below the zygomaticofrontal suture and 4 mm behind the anterior lateral orbital rim. The lateral canthal tendon, Whitnall’s ligament, and Lockwood’s ligament attach here. The medial orbital walls are 45 mm long. The medial wall is composed of the frontal process of the maxilla, the lacrimal bone, the lamina papyracea (ethmoid bone), and the lesser wing of the sphenoid bone. The anterior lacrimal crest forms the attachment for the medial canthal tendon. The lacrimal fossa and sac lie between the anterior and posterior lacrimal crests. The anterior and posterior ethmoid foramina transmit the anterior and posterior ethmoid arteries and demarcate the level of the cribriform plate and floor of the cranial fossa. The average distance from the anterior lacrimal crest to the anterior ethmoid foramen is 24 mm, to the posterior ethmoid foramen is 36 mm, and to the optic foramen is 42 mm.4

The orbital floor is formed by the zygomatic bone, the orbital plate of the maxilla, and the orbital process of the palatine bone. The orbital floor ends at the inferior orbital fissure posteriorly, which transmits the sphenopalatine ganglion, and the maxillary division of the trigeminal nerve. The infraorbital neurovascular bundle travels through the infraorbital groove, canal, and foramen. The infraorbital foramen lies 8 mm inferior to the inferior orbital rim.4

The optic foramen, within the lesser wing of the sphenoid, transmits the optic nerve, ophthalmic artery, and sympathetic fibers to the orbit. The superior orbital fissure is bounded by the greater and lesser wings of the sphenoid. The annulus of Zinn is a fibrous ring surrounding the optic foramen and superior orbital fissure. The superior orbital fissure transmits cranial nerve IV, ophthalmic and mandibular divisions of cranial nerve V, cranial nerve VI, the nasociliary nerve, the superior and inferior ophthalmic veins, the lacrimal nerve, and the frontal nerve.4

Eyebrow Anatomy

Motor Innervation

The temporal, or frontal, division of the facial nerve supplies the muscles of the forehead and the orbicularis oculi muscle. This division of the facial nerve courses from the parotid gland, anterior to the superficial temporal artery, toward its final destination, where it pierces the undersurface of the frontalis muscle 1.5 cm above the lateral canthus. The frontal branch of the facial nerve lies deep to the superficial musculoaponeurotic system fascia (SMAS) and its continuation in the temporal region, the temporoparietal fascia (Fig. 30-4). The course of the nerve may be approximated by a line drawn from a point 0.5 cm anterior to the tragus to a point 1.5 cm lateral to the lateral brow. The danger zone for the temporal branch of the facial nerve has been further described and is shown in Fig. 30-5. The nerve enters the orbicularis oculi muscle and frontalis muscle along the deep surface of the muscles. As the nerve crosses over the zygomatic arch, it lies between the periosteum of the zygoma and the SMAS. Dissection in the region of the zygomatic arch requires caution to avoid injury to the nerve and should be carried out either subcutaneously or subperiosteally.4,5

image

Figure 30-4. Temporal branch of facial nerve deep to the superficial musculoaponeurotic system fascia and temporoparietal fascia.

(From Weinberger MS, Becker DG, Toriumi DM. Rhytidectomy. In: Cummings C, Fredrickson J, Harker L, Krause C, Richardson M, Schuller D, eds. Otolaryngology Head and Neck Surgery. 3rd ed. St. Louis: Mosby; 1998:650.)

image

Figure 30-5. The danger zone for the temporal branch of the facial nerve, defined as the region overlying the zygomatic arch between 1.8 cm anterior to the helical root and 2 cm posterior to the anterior end of the arch.

(From Weinberger MS, Becker DG, Toriumi DM. Rhytidectomy. In: Cummings C, Fredrickson J, Harker L, Krause C, Richardson M, Schuller D, eds. Otolaryngology Head and Neck Surgery. 3rd ed. St. Louis: Mosby; 1998:650.)

Fascial Layers of the Forehead and Temporal Region

The scalp consists of five layers: the skin, subcutaneous tissue, galea aponeurosis, loose areolar tissue, and periosteum. The galea is a tendinous, inelastic sheet of tissue that connects the frontalis muscle of the forehead with the occipitalis muscle. The frontalis muscle originates from the galea and inserts into the forehead skin. At the superior orbital rim, the galea becomes tightly adherent to the periosteum. Laterally, the galea continues as the temporoparietal fascia, which lies in the immediate subcutaneous plane in the temporal region. The temporoparietal fascia is continuous with the SMAS layer of the face and the platysmal layer of the neck (Fig. 30-6). Deep to the temporoparietal fascia lies the deep temporal fascia, which envelops the temporalis muscle. The temporal fascia is contiguous with the calvarial periosteum at the temporal line of the skull, the conjoint tendon. The temporal fat pad, just superior to the zygomatic arch, is ensheathed by the temporal fascia inferior to the level of the supraorbital ridge. At that point, the temporal fascia splits to become the intermediate temporal fascia and the deep temporal fascia, with the fat pad between them. The intermediate fascia layer attaches to the superior aspect of the zygoma laterally, whereas the deep layer attaches medially.4,5

image

Figure 30-6. The superficial musculoaponeurotic system and the temporoparietal fascia is one continuous layer.

(From Weinberger MS, Becker DG, Toriumi DM. Rhytidectomy. In: Cummings C, Fredrickson J, Harker L, Krause C, Richardson M, Schuller D, eds. Otolaryngology Head and Neck Surgery. 3rd ed. St. Louis: Mosby; 1998:649.)

Musculature

There are four muscles in the eyebrow: frontalis, procerus, corrugator supercilii, and orbicularis oculi (Fig. 30-7). The frontalis is a paired subcutaneous muscle that inserts into the skin of the eyebrow. It is the continuation of the galea aponeurotica from the coronal suture downward, and inserts in the dermis at the level of the supraorbital ridge. Laterally, the frontalis terminates at the conjoined tendon. The frontalis muscle has no bony insertions, and its only action is brow elevation. Horizontal forehead rhytids correspond to the long-term effects of frontalis activation. Inferonasally, the frontalis muscle extends to form the procerus muscle. The procerus originates on the caudal aspect of the nasal bones and cephalic margins of the upper lateral cartilages, and inserts onto the medial belly of the frontalis muscle and the dermis between the eyebrows. The action of the procerus muscle produces inferior brow displacement and is responsible for horizontal glabellar wrinkles (Fig. 30-8).

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Figure 30-7. Eyebrow muscles include the frontalis procerus, corrugator supercilii, and orbicularis oculi.

(From Graney DO, Baker SR. Anatomy. In: Cummings C, Fredrickson J, Harker L, Krause C, Richardson M, Schuller D, eds. Otolaryngology Head and Neck Surgery. 3rd ed. St. Louis: Mosby; 1998:404.)

image

Figure 30-8. Corrugator supercilii contraction causes vertical glabellar rhytids and procerus contraction causes horizontal glabellar rhytids.

(From Graney DO, Baker SR. Anatomy. In: Cummings C, Fredrickson J, Harker L, Krause C, Richardson M, Schuller D, eds. Otolaryngology Head and Neck Surgery. 3rd ed. St. Louis: Mosby; 1998:404.)

The corrugator muscle originates from the nasal process of the frontal bone, near the superomedial orbital rim, and inserts into the dermis at the middle third of the eyebrow after blending with the frontalis and orbicularis muscles. Its action produces inferior and medial forehead and brow movement, and results in vertical glabellar wrinkle.4,5

Eyelid Anatomy

The eyelids are the protective covering over the eyes. They consist of an anterior and posterior lamella. At the level of the tarsal plates, the upper and lower eyelids consist of the same basic components: The anterior lamella consists of skin and orbicularis oculi muscle; the posterior lamella consists of tarsus and conjunctiva. The two lamellae are separated by finely interdigitating eyelid retractors. The anterior and posterior lamellae have separate blood supplies that are important to recognize when approaching eyelid reconstruction (Fig. 30-9).4

image

Figure 30-9. The cross section of the orbit and eyelid.

(From Colton JJ, Beekhuis GJ. Blepharoplasty. In: Cummings C, Fredrickson J, Harker L, Krause C, Richardson M, Schuller D, eds. Otolaryngology Head and Neck Surgery. 3rd ed. St. Louis: Mosby; 1998:680.)

Surface Anatomy of the Eyelids

The normal horizontal palpebral fissure is 28 to 30 mm and the normal vertical palpebral fissure is 9 to 10 mm. The intercanthal distance, the distance between the medial canthi of the two eyes, is approximately 25 to 30 mm. The upper eyelid margin normally rests at a point midway between the superior corneal limbus and the pupil, whereas the lower eyelid margin typically abuts the inferior corneal limbus. The apex of the upper eyelid is located midway between the medial pupillary margin and the medial corneal limbus. The nadir of the lower eyelid is at the lateral corneal limbus.6

The upper lid crease is the line formed by the insertion of the levator aponeurosis and orbital septum into the orbicularis oculi muscle and skin. In women, the lid crease is 10 to 12 mm above the lid margin, whereas in men it is 7 to 8 mm above the lid margin. The lateral canthal angle is more acute and 2 mm higher than the rounded and lower medial canthal angle (Fig. 30-10).4,6

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Figure 30-10. The lid crease is 10 to 12 mm above the lid margin in women and 7 to 8 mm above the lid margin in men.

(From Colton JJ, Beekhuis GJ. Blepharoplasty. In: Cummings C, Fredrickson J, Harker L, Krause C, Richardson M, Schuller D, eds. Otolaryngology Head and Neck Surgery. 3rd ed. St. Louis: Mosby; 1998:678.)

A number of anatomic differences exist between the Asian and Occidental eyelids. In the Asian eyelid, the orbital septum and levator aponeurosis attach to the skin further inferiorly, anterior to the tarsus. As a result, orbital fat prolapses anteriorly, thereby preventing the formation of a prominent upper eyelid crease and creating a fullness of the upper eyelid.4,5

The Anterior Lamella

The skin of the eyelids is the thinnest skin of the body with almost no reticular dermis, and it is highly vascular. These factors allow the eyelid skin to heal rapidly and with minimal scar. As it approaches the orbital rim and the hair-bearing areas of the periorbital region, the skin of the eyelids thickens rapidly. The changes in skin thickness are important to consider when planning incisions in periorbital surgery (see Fig. 30-9).46

The orbicularis oculi muscle is a subcutaneous muscle that serves as the sphincter of the eyelid. It is innervated by the temporal and zygomatic branches of the facial nerve. In addition to its function in eye closure, the orbicularis oculi muscle is essential for the proper functioning of the lacrimal pump apparatus, which propels tears into the puncta, canaliculi, and lacrimal sac. Failure of the pump mechanism, as may result with facial nerve paralysis, may result in epiphora.46

The orbicularis oculi muscle is divided into three segments: the pretarsal, preseptal, and orbital segments (Fig. 30-11). Even though they all act to close the eye, each segment plays a unique role. Blinking is an involuntary action that depends on contraction of the pretarsal orbicularis. Winking is a voluntary action dependent upon the orbital orbicularis. The preseptal fibers contribute to both the involuntary and voluntary functions of the eyelids.46

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Figure 30-11. The sphincter mechanism of the eyelids depends on the three divisions of the orbicularis oculi muscle.

(From Colton JJ, Beekhuis GJ. Blepharoplasty. In: Cummings C, Fredrickson J, Harker L, Krause C, Richardson M, Schuller D, eds. Otolaryngology Head and Neck Surgery. 3rd ed. St. Louis: Mosby; 1998:679.)

The origin of the pretarsal orbicularis arises from two heads, one of which inserts into the posterior lacrimal crest, and the other inserts into the anterior lacrimal crest and into the anterior limb of the medial canthal tendon. The preseptal orbicularis also has two heads at its origin: the deep portion attaches to the lacrimal sac, and the superficial segment attaches to the anterior limb of the medial canthal tendon. The orbital orbicularis originates at the anterior limb of the medial canthal ligament and interdigitates with the frontalis, corrugator, and procerus muscles. Laterally, the three orbicularis segments fuse to form the inferior and superior crura of the lateral canthal tendon, which insert into Whitnall’s tubercle. The lateral attachments of the lateral canthal tendon to Whitnall’s tubercle are responsible for eyelid and globe apposition.46

The Orbital Septum

The orbital septum, which lies just deep to the orbicularis oculi muscle, forms the anterior border of the orbit and confines the orbital fat (see Fig. 30-9). It is a fibrous sheath formed at the orbital rims at the arcus marginalis and is an extension of the orbital periosteum. In white upper lids, the septum fuses with the levator aponeurosis approximately 3 mm above the superior tarsal border. In Asian upper lids, the septum fuses with the levator aponeurosis further inferiorly, below the superior tarsal border, thereby allowing orbital fat to lie anterior to the tarsal plate, preventing the attachment of the levator to the skin, and preventing the formation of an upper eyelid crease. In the lower lids, the septum fuses with the underlying orbital retractor (capsulopalpebral fascia), 5 mm below the inferior tarsal border. The orbital septum acts as a barrier to the spread of infection and neoplasms between the preseptal space and the orbital space.4

Upper Eyelid Retractors

Deep to the fat pads are the eyelid retractors. In the upper lid, the levator palpebrae superioris (the levator muscle) is the major retractor, and it originates from the lesser wing of the sphenoid bone at the orbital apex (see Fig. 30-9). The levator is innervated by the oculomotor nerve (cranial nerve III). The horizontal posterior segment of the levator consists of muscle fibers, which extend anteriorly along the orbital roof for 36 mm until it reaches Whitnall’s ligament. At Whitnall’s ligament, the levator changes its course by approximately 90 degrees and becomes an aponeurosis that travels vertically for a length of 14 to 20 mm until its insertion into the upper third of the tarsal plate. Some fibers of the levator aponeurosis fuse with the orbital septum approximately 2 to 5 mm above the superior tarsal border, and then together insert into the skin to create the upper eyelid crease. In addition to its inferior attachments to the septum, tarsal plate, and skin, the levator aponeurosis attaches medially to the medial canthal tendon, and laterally to the lateral canthal tendon.4

Müller’s muscle, or the superior tarsal muscle, arises from the undersurface of the levator aponeurosis just below Whitnall’s ligament, and courses inferiorly 10 to 12 mm to attach to the superior tarsal plate (see Fig. 30-9

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