Upper Third

Aging is associated with (1) hairline recession, (2) transverse forehead rhytids, (3) vertical glabellar lines, and (4) eyebrow ptosis.

Middle Third

Aging is associated with (1) blepharochalasis, (2) ptosis, (3) lower lid laxity ± ectropion, (4) lower lid fat bulge, (5) Crow’s feet, (6) tear trough deformity, (7) palpebromalar groove, and (8) malar mound.

The Lower Third and Neck

Aging is associated with (1) nasolabial fold bulge, (2) nasolabial crease deepening, (3) marionette lines, (4) exaggeration of the labiomental fold, (5) perioral wrinkles, (6) loss of the cervicomental angle, and (7) platysmal bands.

The Temporal Region

The Inferior Temporal Septum (Orbicularis-Temporal Ligament)

This is an area of fusion between the superficial temporal fascia (temporoparietal fascia) and the superficial layer of deep temporal fascia extending from the craniolateral corner of the orbicularis oculi to the external acoustic meatus which constitutes this structure (Fig. 22‑4). ⁶⁶ It divides the temporal compartment into superior (see earlier) and inferior temporal compartments; the latter is further bordered caudally by the zygomatic ligaments. ⁶⁶ This space is surgically significant for housing the frontal branches of the facial nerve, the zygomaticotemporal nerve, and the sentinel veins (Fig. 22‑5). ⁶⁶ The frontal branches of the facial nerve travel medial and parallel to the inferior temporal septum. The septum thus acts as a warning sign during craniocaudal dissection in the temporal region, alerting surgeons to stay strictly on top of the superficial layer of the deep temporal fascia (or deep to it) to avoid nerve injury (Fig. 22‑4). ^{63 , 66}

The Periorbital Area

The Orbicularis-Retaining Ligament (Orbitomalar Ligament)

The anatomical delineation of this structure stems from the clinical observation of constant strong attachments between the orbicularis oculi and the inferolateral orbital rim that often need to be released for adequate periorbital mobilization. ^{66 , 67 , 68 , 69} The orbitomalar ligament (ORL) is an osteocutaneous ligament arising from the periosteum of the orbital rim and traversing the orbicularis oculi to insert into the dermis of the lid–cheek junction (Fig. 22‑6). ^{68 , 70} It is not well defined medially where the orbicularis oculi is tightly adherent to the inferior orbital rim (Fig. 22‑7). ⁶⁸ The ligament extends circumferentially around the orbital rim, and thus forms the roof of the preseptal space in the upper eyelid, the floor of the preseptal space in the lower eyelid, and the roof of the prezygomatic space in the midface, which is bordered caudally by the medial extent of the zygomatic ligaments. ^{67 , 68 , 69} Morphologically, the ligament is a bilaminar structure where the cranial leaf is a reflection of the orbital septum, and the caudal leaf a continuation of the fascia covering the preperiosteal fat of the prezygomatic space. ^{68 , 69} The zygomaticofacial nerve and foramen always lie peripheral to the ORL. ^{68 , 69} The ORL can be thought of as the leash of a dog running from bone to dermis. The leash is tight medially, loose centrally, and again tight laterally; where it fuses with the lateral orbital thickening or superficial canthal tendon, the laxity of the ligament thus creates a V-shaped structure (Fig. 22‑7). ⁶⁸ Lysis of the medial orbicularis oculi and varying portions of the ORL have become an essential part of a variety of procedures used to treat the tear trough, palpebromalar groove, and malar mound. ^{24 , 69 , 71 , 72 , 73 , 74 , 75 , 76}

The Cheek Area

The zygomatic ligaments arise from the lower border of the zygomatic arch and from the body of the zygoma. ^{9 , 10 , 64} They attach directly to the dermis. ^{9 , 10 , 64} The medial extent of these ligaments forms the floor of the prezygomatic space, while the lateral extent constitutes the lower border of the inferior temporal compartment. ^{66 , 67 , 69} Furthermore, these ligaments act as the roof of the lateral cheek compartment. ⁶³ The major zygomatic cutaneous ligament lies at the junction of the arch and body of the zygoma. ^{63 , 64} This ligament is surgically important because when released, the zygomaticus major (ZM) muscle comes into view. ^{9 , 10 , 35} This marks the end of the sub-SMAS dissection. All sub-SMAS procedures invariably pass superficial or subcutaneous at this point, in order to avoid injury to facial nerve branches (Fig. 22‑8). ^{9 , 17 , 35 , 37}

The masseteric ligaments have their origin from the fascia overlying the masseter muscle. Together with the zygomatic ligaments they form a T-shaped configuration (the confluence of the T is at the origin of the ZM muscle). ^{10 , 33 , 63 , 64} One centimeter inferior to the ZM in the vicinity of the stout upper masseteric ligaments is the sub-SMAS “danger zone,” where care needs to be taken when lysing these ligaments to avoid injury to zygomatic branches of the facial nerve (Fig. 22‑9). ^{9 , 10 , 63 , 64} The lower masseteric ligaments or zones of fusion separate the premasseteric space from the masticatory space that houses the buccal fat pad. ^{10 , 60 , 63}

The platysma auricular ligament/fascia is the first ligament severed during a facelift. It is formed of fibrous bands connecting the platysma to the parotid fascia, securing it to the preauricular skin. ^{9 , 10 , 63}

The Mandibular Area

The mandibular ligament is an osteocutaneous ligament arising from the anterior third of the mandible, 1 cm above the inferior border. ⁹ Its presence marks the anterior boundary of the jowl (Fig. 22‑3). ^{9 , 10} The marginal mandibular branches of the facial nerve are located posterior and approximately 1 cm cranial to it (Fig. 22‑10). ⁶⁵

Frontal (Temporal) Branches

The limited number of communications with other facial nerve branches is thought to account for the higher risk of permanent injury. ⁷⁷ The classic surface anatomy is the Pitanguy line which extends from 0.5 cm below the tragus to 1.5 cm above the lateral eyebrow. ⁷⁸ The nerve exists in multiple (2–5) rami that intercommunicate, which may explain the return of function after injury. The branches were found to reside 2 cm posterior to the lateral orbital rim at the level of the lateral canthus. ^{79 , 80} At the level of the zygomatic arch, the branches run over the middle third approximately 1.8 cm anterior to the helical crus, and 2 cm posterior to the lateral orbital rim (Fig. 22‑11). ^{79 , 81} In terms of depth, these branches are closely applied to the periosteum of the zygomatic arch, deep to both the SMAS and the parotid masseteric fascia (parotid temporal fascia). ⁸² Superior to the arch, they travel on top of the superficial layer of the deep temporal fascia. ^{82 , 83 , 84} Trussler et al and Agarwal et al in separate studies showed the presence of two superficial fascial layers covering the zygomatic arch and the deep temporal fascia. ^{82 , 84} The first layer is the superficial temporal fascia, which is in continuity with the SMAS. ^{82 , 84} Deeper to it they showed the existence of another distinct layer (the parotid temporal fascia per Trussler et al, and innominate fascia per Agarwal et al). ^{82 , 84} The frontal branches travel either deep or within this deeper layer. ^{82 , 84} This relationship continues for at least 1.5 to 3 cm above the arch from where the nerves start to transition through the superficial temporal fascia to merge with the anterior branch of the superficial temporal artery as they approach orbicularis oculi and frontalis. ^{82 , 84} Appreciation of this anatomy is important during craniocaudal dissections in the temporal region, and in elevating a high SMAS flap. ⁸² Surgeons should stay strictly on top of the superficial layer of the deep temporal fascia (or deep to it) elevating the frontal branches with the flap. Two centimeters cephalad to the zygomatic arch, dissecting deeper to the superficial layer of the deep temporal fascia has been advocated to avoid nerve injury. ^{77 , 82 , 84} In endoscopic brow lift, the sentinel vein (located approximately 0.5 cm lateral to the frontozygomatic suture) defines a danger zone about 10 mm cephalad, where the frontal branch is liable to injury (Fig. 22‑5). ⁸¹ A second vein 1.5 cm lateral to the first is occasionally identified. ⁸¹

Zygomatic and Buccal Branches

These branches display higher number of rami and interconnections which may account for spontaneous recovery following injury (Fig. 22‑2 and Fig. 22‑9). ⁷⁷ The buccal ramus is thought to be the most frequently injured facial nerve branch in rhytidectomy. ^{36 , 77} Due to extensive arborization, clinical effect is usually short-lived and rarely discernible. ^{36 , 77} Injury to the branches that supply the elevators of the upper lip (e.g., ZM), however, can potentially affect smile. The area inferior to the zygomatic ligaments and anterior to the upper masseteric ligaments is a danger zone ^{9 , 10 , 63 , 77} . Thus, sub-SMAS dissection in this region should proceed with extreme caution, always hugging the undersurface of the SMAS and keeping all fat down.

Marginal Mandibular Branch

The limited number of rami and communications with other facial nerve branches is thought to account for higher risk of permanent injury (Fig. 22‑9 and Fig. 22‑10). ⁷⁷ Anatomical studies have shown the nerve to be composed of at least two rami. Posterior to the fascial vessels they travel within 1 cm (rarely 2 cm or more) of the mandibular border (more frequently cephalad than caudad). ^{65 , 77 , 83 , 85} In contrast, anterior to the facial vessels the marginal mandibular is always cranial to the mandibular border traveling toward the depressor anguli oris. ^{77 , 83 , 85} Here, it lies posterior and approximately 1 cm cranial to the mandibular ligament ⁶⁵ (Fig. 22‑8). In terms of depth, the nerve emerges from the lower end of the parotid gland and travels deep to the parotid-masseteric fascia, and under cover of platysma. ^{65 , 77 , 83 , 85} Inferior to the mandible it courses on the surface of the posterior belly of digastric and submandibular gland remaining deep to platysma. ^{77 , 83 , 85} At the level of the facial vessels, the nerve crosses the mandibular border superficial to these vessels. It is at this point that the nerve is believed to be at higher risk of injury as it becomes more superficial. ⁷⁷ The nerve remains deep to the platysma throughout its course, and thus keeping dissections above the platysma is a safe dissection plane. In sub-SMAS dissections, the lower masseteric ligaments are a sign of caution to the proximity of the marginal mandibular branches.

Cervical Branch

Injury to this branch is believed to result in marginal mandibular pseudo-paralysis secondary to dysfunction of the platysma which is likewise a depressor of the lower lip (Fig. 22‑9). ^{86 , 87} Clinical differentiation is possible by demonstrating retained ability to pucker the lower lip, which signifies residual orbicularis oris and mentalis function. ^{86 , 87} Return of function is almost always complete. ^{86 , 87} This nerve (composed of one to three rami with occasional communication to the marginal mandibular) travels close to the gonial angle and branches approximately 1.74 mm inferior to the mandibular border. ^{88 , 89} Platysmal incisions should be designed at least 15 mm posterior to the gonial angle, and 45 mm caudal to the mandibular border to avoid cervical nerve injury. ^{88 , 89} It emerges from the lower border of the parotid gland and remains deep but close to the undersurface of the platysma. ^{77 , 88 , 89} Thus, subplatysmal dissection in proximity to the gonial angle should proceed with caution staying superficial to the underlying fat. Blunt dissection has been advocated in this plane inferior to the tail of the parotid to minimize injuries of the marginal mandibular and cervical branches. ^{77 , 89}

Sensory Nerves

The great auricular nerve (C2 and C3) is thought to be the most commonly injured nerve in rhytidectomy. ⁹⁰ Arising from the cervical plexus, it winds around the posterior border of the sternocleidomastoid, and passes vertically upward toward the middle of the lobule of the ear. ⁹¹ The classic surface landmark is McKinney’s point which lies 6.5 cm caudal to the external acoustic meatus approximately 0.5 to 1 cm posterior to the external jugular vein. ⁹⁰ Ozturk et al have identified a triangle, where the nerve can be found 100% of the time. ⁹² The triangle is defined by a line perpendicular to the Frankfort horizontal bisecting the lobule of the ear and another diverging 30 degrees posterior to it (Fig. 22‑12). ⁹² Maintaining the dissection superficial to the sternocleidomastoid fascia in this region prevents nerve injury and consequent neuroma formation. ⁹²

The Preauricular Part

A preauricular retrotragal incision results in less discernible postoperative scarring. ³² If properly executed, the aesthetic outcome is excellent. The potential for tragal deformity is readily preventable if care is taken to avoid cartilage injury and ensure tensionless closure (Fig. 22‑13; Fig. 22‑14). ³²

The Temporal Extension

An outer canthus to temple distance less than 5 cm permits a temporal scalp extension. A distance greater than 5 cm mandates a temporal hairline incision to avoid aggravation of temporal recession (Fig. 22‑15). ^{32 , 47 , 48 , 93}

The Postauricular Extension

The incision follows the postauricular sulcus and crosses the postauricular skin where the helix and postauricular hairline touches (Feldman’s “touch point”). ⁹⁴ It either continues horizontally into the occipital scalp or follows within the occipital hairline. ^{32 , 55 , 94} The latter prevents posterior hairline recession especially if neck skin laxity is profound (Fig. 22‑16). ^{32 , 55 , 94}

Submental Incision

A 3.5-cm horizontal incision is centered over the midline approximately 5 mm caudal to the submental crease if anterior cervicoplasty/platysmaplasty is contemplated. ^{41 , 42}

Principle

The extended SMAS technique delaminates the face by raising separate skin and SMAS flaps. ³⁵ The independent mobility of SMAS and skin permits greater versatility in vector selection and direction of tissue repositioning. ^{34 , 36 , 37} Precise control of dissection plane and skin flap thickness is critical, however, to avoid tearing of the SMAS flap. ^{34 , 37} The SMAS thins considerably as dissection extends medially and SMAS tearing can complicate flap fixation. ^{8 , 34 , 37 , 46}

Dissection

The Temporal Region

It is prudent to stay on top of the superficial temporal fascia. This is the layer immediately deep to the hair follicles. Proceeding anteriorly, the orbicularis oculi muscle is identified, and more caudal dissection should continue superficial to the plane of this muscle (Fig. 22‑17). ³²

The Preauricular and Cheek Part

Immediately anterior to the helical crus, dissection should be very superficial (subdermal), to avoid injury to the superficial temporal vessels; this part of the skin is usually discarded anyway except in secondary cases. At the tragus, caution is necessary to prevent cartilage injury. In the cheek area (from the zygomatic arch to the mandible), dissection should be more superficial to preserve fat on top of the SMAS, thus providing a thicker SMAS flap. ^{32 , 35} Moving across the mandible to the neck, the plane transitions smoothly to a slightly deeper level. Dissection anterior to the sternocleidomastoid muscle should be hugging the superficial surface of the platysma (Fig. 22‑18).

The SMAS Flap and Sub-SMAS Dissection

SMAS Flap Elevation

Starting sub-SMAS dissection over the parotid gland mitigates potential nerve injury, since parotid tissue serves as an extra layer protecting the nerves. The SMAS is also thicker, muscular, and more distinct in this region (Fig. 22‑8). Anterior to the parotid, it is critical to hug the deep surface of the SMAS flap, maintaining all fat over the masseteric fascia protecting the facial nerve branches lying deep (Fig. 22‑8). Once the proper plane is identified, more cephalad dissection can be undertaken. Malar SMAS is mobilized severing zygomatic and upper masseteric ligaments with extreme care (see section 22.6 Anatomical Considerations). ^{32 , 35 , 36 , 37} Amidst this dissection, ZM muscle is identified (Fig. 22‑8). ^{32 , 35} Dissecting medial to ZM disconnects any remaining zygomatic ligaments, while caudal to it, the masseteric ligaments are split. ³⁵ Maintaining the dissection superficial to the plane of this muscle protects the nerves. Using blunt spreading motion, dissection continues to the nasolabial crease. ³⁵ This maneuver ameliorates the depth of the crease and simultaneously lifts the malar fat pad. ³⁵ Further, malar fat mobility can be achieved using finger dissection in the same plane: “FAME” (finger-assisted malar elevation). ⁹⁵ An effective SMAS flap should improve the jowl and the neck and reposition the malar fat pad. ^{32 , 35} The SMAS elevation has a decidedly positive and powerful effect on platysma tightening and gonial angle improvement because the platysma is continuous with the SMAS and has no bony attachments.