Anatomy Course 7.19.05

Dr. Pastorek and Rickert Topic: Anatomy of the face (facial bones, SMAS, temporoparietal fascia, muscles, skin) Course of the temporal and marginal branches of the facial nerve Dissection: Coronal approach to the osteoplastic flap Facelift flap

1. Facial Bones

1. Frontal bone a. Supraorbital notch b. Articulates medially with the frontal process of the maxilla and nasal bones c. Articulates laterally with the zygomatic bone

2. Zygomatic bone a. Facial buttress b. Tripod fracture

i. Inability to close one’s mouth because coronoid process of the mandible impinges on the medially displaced zygoma

3. Maxillae a. Body b. Four processes: frontal, palatine, zygomatic, alveolar c. Intermaxillary suture d. Foramina

i. posterior superior dental, incisive, palatine canal, nasolacrimal canal, infraorbital groove, ostium to the maxillary sinuses

4. Nasal bones 5. Lacrimal bones 6. Vomer 7. Palatine bones

a. Horizontal plates form part of the hard palate 8. Mandible

a. Body b. Vertical plates – rami c. Mental protuberance/chin (syphyseal/parasymphyseal regions) d. Coronoid process e. Condyle f. Mental foramen

2. Facial Skin

1. Epidermis

a. Five cell layers (stratum basale, spinosum, granulosum, corneum) b. On palms and soles, lucidum is between granulosum and corneum c. Types of cells: keratocytes (80%), melanocytes, Langerhans’ cells (immunological

cells in skin), Merckel’s cells (associated w/terminal nerve endings in skin) d. Basement membrane zone under stratum basale

2. Dermis

a. Papillary dermis (thin) b. Reticular Dermis (thick) c. Collagen, elastin, and ground substance d. Fibroblasts, macrophages, and mast cells e. Lymphatic channels f. Pilosebaceous follicle g. Sweat glands

3. Subcutaneous tissue

a. Lobules of adipose tissue and areas of fibrous septae b. Known as superfical fascia layer

4. Aging a. Decreased epidermal thickness b. Retraction of and decreased number of rete ridges (projections at bottom of

epidermis which help to anchor epidermis into dermis) c. Decreased moisture content leading to dryness and roughness d. Decreased melanocytes and Langerhans’ cells e. Decreased collagen by 1% per year f. Decreased elastin/elasticity g. Decreased vascularity of dermis h. Decreased amount of glands i. Decreased subcutaneous fat j. Wrinkling

3. Facial Muscles

1. Mouth

a. Depressor anguli oris b. Depressor labii inferioris c. Orbicularis oris d. Risorius e. Buccinator f. Zygomatic major g. Zygomatic minor

h. Levator labii superioris i. Levator labii superioris alaeque nasi j. Levator anguli oris

2. Nose a. Alaeque nasi b. Depressor septi c. Nasalis d. Procerus

3. Eyelid a. Orbicularis oculi b. Corrugator supercilii

4. Auricle a. Anterior auricular muscle b. Posterior auricular muscle c. Superior auricular muscle

5. Scalp a. Occipitofrontalis

4. Facial Innervation and Vasculature

5. SMAS (Superficial Musculoaponeurotic System)

1. Described initially in 1976 by Mitz and Peyronnie 2. Fibromuscular layer representing cephalad continuation of superficial cervical fascia

a. Extends from frontalis muscle superiorly to platysma inferiorly 3. Translates facial muscle action to dynamic action in facial skin 4. Above zygomatic arch, continuous with temporoparietal fascia 5. Continues superiorly as galea aponeurotica of scalp 6. Skin is directly connected to SMAS by fibrous filaments, especially in midface (perioral,

nasolabial, periorbital) 7. Located above parotid fascia, facial nerve, facial artery 8. Thickness and adherence characteristics vary in different regions

a. Adherent to underlying parotidomasseteric fascia in cheek b. Dense adherence over zygomatic arch to periosteum (deep temporal fascia)

6. Temporoparietal Fascia

1. Temporoparietal scalp consists of 5 layers. Temporoparietal fascia is the third layer. 2. Fascial plane immediately beneath skin and subcutaneous fat of temporal area 3. Superficial temporal artery and vein run in temporoparietal fascial layer 4. Temporoparietal Fascia continuous with SMAS in lower face, galea aponeurotica

superiorly (above superior temporal line) 5. Beneath temporoparietal fascia is deep temporal fascia/true temporal fascia

a. Temporal fascia splits at the level of the supraorbital ridge to become the intermediate temporal fascia and deep temporal fascia with intermediate fat pad

6. Head and neck reconstruction: most commonly used as pedicle flap w/intra-oral reconstruction.

7. Facial Nerve

1. Emerges from intratemporal course at stylomastoid foramen and travels anterolaterally

through parotid gland 2. Medially, nerve branches emerge deep to parotidomasseteric fascia to innervate mimetic

muscles on their deep surfaces 3. Dissection deep to SMAS beyond parotid gland poses risk of nerve injury 4. Branches

a. Temporal branch emerges from parotid gland below zygomatic arch, crosses arch on undersurface of SMAS (danger zone)

b. Zygomatic brnach courses 1 cm below zygomatic arch superiorly and medially from tragus to lateral canthus

c. Marginal branch exits parotid 1 cm below mandibular angle, deep to platsyma within submandibular gland

5. Innervates all facial muscles deeply except the buccinator, levator angular oris, mentalis muscles

Coronal approach to the osteoplastic flap

1. Used for refractory frontal sinusitis, mucoceles, tumors, or those accompanied by

intracranial complications or frontal sinus fractures 2. Hypoplastic frontal sinuses are a contraindication for obliteration 3. 3 possible approaches

a. Coronal i. useful and cosmetically acceptable if patient is not balding ii. may involve more blood loss

b. Midline forehead i. incorporated into a patient forehead wrinkles

c. Brow incisions i. least cosmetically acceptable ii. may cause postop pain, paresthesias

4. Caldwell-Luc image preoperatively obtained at 6ft distance provides a good template for frontal sinuses

5. After one of the 3 approaches is used, frontal periosteum is cleaned of subcutaneous tissue

a. Coronal flap incision made 1 inch posterior to hairline b. Uses a biocoronal flap, leaving the pericranium intact

6. Use templates to outline frontal sinuses 7. Periosteum is incised 5 mm above the outline of the sinus and elevated to just below the

sinus outline 8. Power saw is used to cut the sinus by beveling the blade downward and inward by

following template 9. Osteoplastic flap is then fractured from above, exposing the contents of the frontal sinus 10. Removal of all sinus contents, including intersinus septum if necessary 11. Drill sinus out with polishing burr to ensure all mucosa is removed in preparation of fat

graft a. if osteomyelitis is involved in the sinus, it is possible to remove bone, allowing dura

to occupy frontal sinus space

12. Pack frontal sinus space with fat graft/other materials before replacing osteomeatal flap a. Many substances can be used including Gelfoam, Teflon, fat, paraffin, cartilage,

solastic sponge. b. Autogenous fat is most commonly used, thought to prevent osteoneogenesis and

impede regrowth of mucosa/periosteum 13. Suture periosteum and incision in layers 14. Pressure dressing is applied to forehead, removed 1-2 days later 15. Postoperative antibiotics 16. Complications (18%)

a. seroma, hematoma, abscess formation most common b. dural exposure/laceration, nasal skin necrosis, anosmia, temporary ptosis,

temporary loss of frontalis muscle 17. Why use the osteoplastic flap?

a. Excellent visualization of sinus b. Ability to correct problems of the posterior table/dura is needed c. Elimination of need to establish frontonasal communication d. Low failure rate

i. 93% with resolution of frontal sinusitis after 3 years ii. 6% of patients need revision surgery due to recurrent frontal sinusitis

18. Why not use the osteoplastic flap? a. Post operative follow-up is more difficult since the sinus is obliterated

Facelift flap (Rhytidectomy) 1. Cosmetic surgery designed to reposition facial skin to rejuvenate the aging face 2. First used in early 20th century by European surgeons, but no widespread techniques 3. 1920s-1960s used subcutaneous techniques 4. 1974 Skoog used a subfascial facelift, using deeper layer of tissue and placing less tension

on the subcutaneous tissue 5. 1976 Mitz and Peyronie described the SMAS facelift, which remains a gold standard 6. 1990s development of deep-plane facelift and composite rhytidectomies

7. Clinical evaluation and selection of patients is crucial

a. Face lifting will benefit a patient most if they have elasticity in skin, paucity of subcutaneous fat, good bony landmarks, age in 40-50s

b. Careful explanation of limitations of the surgery and potential problems c. Photographic records of any asymmetries d. Analysis of the face (chin, nasolabial folds, jowl area, jaw line, hyoid positioning,

platysma, quality of skin, amount of subcutaneous fat) 1. Turkey Gobbler deformities: loss of cevicomental angle (>120deg)

from platysmal laxity e. Hypertrophic labial folds do not respond well to SMAS lifting

1. Jowl and jaw line improve well with SMAS lifting 2. Hyoid position difficult to alter

1. Low lying hyoid produces an obtuse angle and less attractive angle of cervicomental angle

3. Liposuction and laser facial rejuvenation can be combined with surgical intervention

f. Preoperative workup, thorough H&P 1. History of alcohol, smoking have impact on bleeding/healing

1. Smokers have 12X increase in post-op skin slough 2. History of sun exposure (actinic damage from UVA) 3. History of recent weight loss (wait until weight is stable) 4. Complete medical history (thyroid d/o, allergic dermatitis, collagen

vascular diseases, keloids, bleeding d/o) 8. Anatomy

a. Layers of Facial Planes 1. Skin 2. Subcutaneous Fat 3. SMAS 4. Mimetic muscles 5. Deep facial fascia 6. Deep elements (facial nerve, parotid duct, buccal fat)

b. SMAS distributes the force among the facial mimetic muscles

1. Galea in the scalp, temporoparietal fascia 2. Discontinuous at the level of the zygomatic arch

1. Not used as a surgical plane, secondary to risk to temporal branch

3. Below zygomatic arch, becomes superficial to parotid 4. Anteriorly, envelops the zygomatic major and attaches to nasolabial

crease 1. pulling on SMAS causes widen and deepened nasolabial

crease 5. Platsyma below

c. Vasculature from external carotid arteries 1. majority from facial and infraorbital arteries 2. Important to leave fibrous septa attached to flap to provide good

vascular supply, especially in smokers d. Sensory nerves most commonly injured

1. Greater auricular most common 2. Facial nerve branches most at risk – temporal and marginal

9. Rhytidoplasty Surgical Techniques

a. Mark patient in upright position b. Liposuction may be used to allow shorter flaps and less risk of hematoma c. Chemical peels should not be done concurrently d. Superficial plane technique

1. Addresses redundant skin only 2. A: simple 3. D: does not address deeper tissue , high risk of skin sloughing 2/2

vascular perforator interruption e. Deep plane technique

1. subSMAS dissection from midface to medial melolabial crease 2. elevated cheek fat pad and provides vertical lift 3. A: addresses melolabial crease/midface by separating SMAS from

bony attachments of zygomaticus muscles, excellent jaw line, preserves facial blood supply

4. D: lengthy anterior dissection

f. Composite Technique 1. combines deep technique with orbicularis oculi flap 2. A: repositions zygomaticus major to original position, healthy thick

flap, more avascular dissection 3. D: persistent malar edema, unnatural tension at temple region

g. Subperiosteal technique 1. variation of subperiosteal undermining of orbital rim, zygomatic arch,

maxilla, zygoma body 2. A: maintains skin perforators, addresses midface without unnatural

tension (traction on periosteum) 3. D: prolonged facial edema, limited improvement of jowling, more

challenging h. Multiplane technique

1. extended SMAS dissection and deep plane lift 2. A: separate dissection of SMAS allows better redraping of skin, may

address melolabial crease better 3. D: more compromise of vascualr supply than deep plane lifts with

separate SMAS and skin dissection 4. Triplane technique (subcutaneous in temple and neck, sub-SMAS in

lower cheek, subperiosteal in midface): allows maximal correction of jowl while limiting degree of sub SMAS to lower cheek, protects facial nerve.

10. SMAS Suspension Facelift a. Mainstay for most surgeons b. Several variations to technique c. Frequently in combination with platsymaplasty/liposuction d. Preoperative marking of landmarks and incision lines e. Incisions

1. Temporal incision parallels the gentle curvature of the hair line,

typically 1 cm with the hair to hide scar 1. Incision is carried posteriorly up and over the auricle

2. Preauricular incision follows the preauricular crease (males) behind the tragus/pre-auricular crease (females)

3. Earlobe incision follows the lobule margin 4. Postauricular incision continues posteriorly on the concha to the

inferior crus 5. Mastoid/Occipital incision curves posteriorly gently onto the mastoid 6. Staying close to the hairline you prevent elevation of the hairline

f. Flap elevation

1. Subcutaneous plane is used in all areas except zygoma 2. Zygoma, a subperiosteal plane avoids the temporal branch of VII

3. Dissection begun in peri-auricular area, followed by infra- and pre-

auricular areas. 4. Flap elevation continues anteriorly (3-4 cm) and inferiorly (7-8 cm) in

neck 1. shorter flaps in smokers is safer

5. Neck dissection is made continuous with platysmaplasty

g. SMAS suspension

1. After flaps elevated, SMAS is suspended with plication (sutures) or imbrication (excision)

2. Several sutures are placed along each vector 1. Sutures placed at jaw line and anchored at the mastoid

periosteum/deep tissues in the pre-auricular area 2. Posterosuperior vector in neck is platsyma to SCM

fascia/mastoid periosteum 3. Flattening of jowls is done by vector of SMAS to deep

preauricular tissues

4. SMAS suspension will result in skin excess requiring trimming i. Must eliminate any skin tension for best healing

h. Closure 1. Drains vs. no drains 2. Hair bearing skin can be closed with staples

i. Dressing 1. non-adherent material with gauze fluff wrapped underneath ace

bandage 2. bandage removed after 24 hours, nylon facelift dressing applied

j. Complications 1. Hematoma = up to 8.5%

1. skin necrosis followed unrecognized hematoma 2. opening incision and hemostasis vs. serial drainages

2. Facial nerve injury = 0.4-2.6% 1. Temporal branch most injured, marginal mandibular also at

risk below platysma, buccal at risk in midface deep dissection

3. Sensory nerve injury = 1-7% 1. Greater auricular nerve most common injured

4. Scars 1. hypertrophic scars in retroauricular incision occasionally

i. skin is thin and moderate tension precipitates scar thickening

ii. serial injections can help control scar 5. Hair loss

1. more common along temple incision than postauricular 2. hair regrowth typically occurs in 6 months 3. distortion of hair line may occur if flap does not realign hair line

6. Parotid injury 1. secondary to SMAS flaps and sub-SMAS dissections

7. Pigmentary changes 1. postinflammatory pigmentary changes 2. avoid sun exposure first few months post-op

8. Contour deformities 1. local hematoma not drained post-op 2. excessive fat removal

9. Depression 1. short term situational depression occurs in 50% women

secondary to post-op changes, bruising, edema. 2. Emotional support important in post-operative stage.