Anatomy Course July 10, 2007 Drs. LaBruna and Jourdy Topic: Wound healing, orbit, eye and eyelid anatomy including orbital fissures, optic muscles, optic nerve and its relation to the paranasal sinuses. Anatomy of the nose. Dissection: 1. Blepharoplasty/Rhinoplasty Wound Healing Phases of Wound healing: 1. Inflammatory Phase/Coagulation: initial vasoconstriction and platelet and fibrin aggregation leading to hemostasis followed by vasodilation, increased capillary permeability, migration of cells and fluid, neutrophils predominate during the first 24-48 hours 2. Migratory Phase: macrophages replace neutrophils as the most prevalent cell type at this phase, occurs approximately 2-4 days later, mesenchymal cell proliferation, angiogenesis, and epithelialization. (incisional wounds tend to be completely reepithelialized by 48 hours) 3. Proliferative Phase: collagen formation by fibroblasts begins around day 3-5 and continues for 2-4 weeks; wound contraction occurs via myofibroblasts beginning around day 4 or 5 and continues for 2 weeks, myofibroblasts predominate during this phase until approx day 21. 4. Wound remodeling: Around day 21 scar remodeling occurs, old collagen is broken down and new collagen formation takes place in an organized fashion. Scar remodeling occurs for approx one year. Methods of Wound Closure: 1. Primary intention skin edges approximated using any acceptable closure method 2. Secondary intention wound heals via epithelialization and contraction 3. Third intention/delayed primary intention wound left open for short period of time and then closed by primary intention 4. Skin graft epidermis + part of dermis 5. Flaps rotation flap versus free flap Factors that Inhibit Wound Healing: 1. Malnutrition (Especially Vit C, Vit A, and Zinc) 2. Steroids 3. Radiation 4. Smoking (poor oxygenation) 5. Diabetes 6. Age (Elderly have decreased cell proliferation and metabolic activity)
Orbit Pyramidal structures that contain the eyeballs and their muscles, nerves and vessels as well as the lacrimal apparatus. Four Walls of the Orbit + Apex 1. Superior wall (roof) mainly orbital part of frontal bone along with lesser wing of the sphenoid at apex; holds the fossa for lacrimal gland 2. Medial wall mainly ethmoid bone, along with contributions from the frontal, lacrimal, and sphenoid bones; anteriorly, indented by lacrimal fossa for the lacrimal sac; portion of ethmoid bone also forming part of the lateral wall of the ethmoid labyrinth is paper thin. 3. Inferior wall (floor) mainly maxilla and partly by the zygomatic and palatine bones; separated from the lateral wall of orbit by the inferior orbital fissure. 4. Lateral wall frontal process of the zygomatic bone & greater wing of sphenoid 5. Apex located at the optic canal in the lesser wing of the sphenoid just medial to the superior orbital fissure. Eyelids and Lacrimal Apparatus -eyelids & tears protect cornea & eyeball from injury. Eyelids Covered exteriorly by skin; interiorly by palpebral conjunctiva which continues to the conjunctival fornices where it is continuous with the bulbar conjunctiva. Strengthened by superior and inferior tarsal plates (dense bands of connective tissue), with fibers of orbicularis occuli in the connective tissue just superficial to these plates. Embedded in the tarsal plates are tarsal glands, the lipid secretions of which protect the edges of the eyelids. Upper plate 10mm, Lower plate 5 mm. Attach to the lateral and medial margins of the orbit with the lateral and medial palpebral ligaments which connect to the tarsal plates. The medial palpebral ligament also serves as an origin and insertion point for the orbicularis oris muscle Lacrimal Apparatus Consists of: Lacrimal glands secrete fluid Lacrimal ducts open into superior conjunctival fornices (up to 12 ducts each side) and convey fluid from gland to conjunctival sac Lacrimal canaliculi each commencing at the lacrimal punctum near the medial canthus Nasolacrimal duct conveys fluid to nasal cavity Lacrimal fluid (stimulated by parasympathetic impulses of CN VII) flows from lacrimal ducts across the eye (lateral to medial) to lacrimal lake, enter the lacrimal sac via the canalculi, then flows into the back of the nasal cavity through the nasolacrimal duct.
Orbital Contents Include eyeball, extraocular muscles, fascia, nerves, vessels, fat, lacrimal gland, and sac. Extraocular Muscles - Innervation: i. Motor: LR6 SO4, all else CN 3 ii. Sensory: CN V2 via nasociliary nerve iii. Parasympathetic: 1. lacrimal nerve to lacrimal gland, 2. posterior short ciliary nerves cause pupil constriction and accommodation iv. Sympathetic: 1. Long ciliary nerves cause pupil dilation and vasoconstriction v. Optic nerve: CNII begins where the axons of retinal ganglion cells pierce the sclera and passes posteromedially in the orbit (lateral to the ethmoid cells) - Blood Supply of orbit: mainly ophthalmic artery (ICA), Facial a. (IMA/ECA) - Venous drainage: superior and inferior ophthalmic veins that pass through SOF and enter the cavernous sinus MUSCLE ORIGIN INSERTION INNERVATION EYE MVMT Superior rectus CTR* Sclera CN 3 Elevation,intorsion Inferior rectus CTR* Sclera CN 3 Depression,extorsion Medial rectus CTR* Sclera CN 3 Adducts Lateral rectus CTR* Sclera CN 6 Abducts Levator Sphenoid (lesser wing) Tarsus and skin of upper eyelid CN 3 Sympathetic n. Elevation of upper eyelid Superior oblique** Sphenoid (body) Sclera (beneath SR) CN 4 Rotation down and lateral, intorsion Inferior oblique Orbit floor Sclera (beneath LR) CN 3 Rotation up and lateral, extorsion *CTR= Common Tendinous Ring that surrounds the optic canal **Superior oblique- tendon passes through a fibrous ring or trochlea, changes direction and inserts in sclera. Orbital Fissures 1. Superior Orbital Fissure a. Communicates with middle cranial fossa b. Bounded by greater and lesser wings of sphenoid c. Transmits CN 3, 4, 5(1), 6, sympathetics and superior ophthalmic vein 2. Inferior Orbital Fissure a. Communicates with infratemporal and pterygopalatine fossae b. Bounded by greater wing of sphenoid and, maxillary, and palatine bones c. Transmits infraorbital maxillary nerve and its zygomatic branch, inferior ophthalmic vein
Blepharoplasty Eyelid Anatomy (anterior to posterior). 1. Skin - thin, loose, and mobile over the deeper structures, becomes coarser, thicker, and more sebaceous lateral to the bony margin, upper lid skin is well vascularized and healing occurs quickly with favorable scar formation. 2. Orbicularis: a. Outer orbital portion b. Inner palpebral portion i. Pretarsal overlies the tarsal plate ii. Preseptal - overlies the orbital septum c. Lateral and medial segments of the orbicularis participate with the tarsal plate in the formation of the canthal tendons 3. Orbital septum key structure and landmark in blepharoplasty, a thin sheet of fibrous tissue that originates along the superior orbital rim and hangs like a curtain across the lid. It joins the levator aponeurosis by interdigitating fibers at the upper edge of the tarsal plate. The septum keeps the orbital fat in its posterior position. Weakening of the septum with aging, hereditary predisposition, or trauma may cause protrusion of the orbital fat. 4. Preaponeurotic fat provides a cushion to the structures of the orbit, separates the orbital septum from the levator aponeurosis. a. The upper lid has 2 fat compartments i. Central larger, fat is more yellow ii. Nasal lighter in color, more dense, laterally, the fat may be associated with the lacrimal gland (more granular in consistency). b. The lower lid has three fat compartments i. medial - small, lighter in color, more dense ii. temporal small iii. central large 5. Levator aponeurosis primary elevator of the eyelid a. Origin: orbital periosteum and passes forward above the superior rectus muscle, gradually forming a tendon that fans out to form the levator aponeurosis i. Extends the full width of the lid at the level of the upper tarsus where the tendon fuses with the orbital septum to insert in the anterior third of the tarsus ii. Fibers from the aponeurosis blend with those of the orbital septum at the level of the tarsus and insert into the orbicularis muscle, subcutaneous tissue and skin to produce the lid crease. iii. Mueller's muscle originates from the belly of the levator aponeurosis and inserts at the retrotarsal margin. It is closely associated with the underlying tarsus and vascular arcade. 6. Tarsus skeleton of the eyelid, a fibrous plate that is approximately 10 mm wide in the central upper lid, narrowing medially and laterally. The tarsus of the lower lid is a bit narrower, from 4-5 mm at its center. The tarsal plates extend from the lateral commissure to the punctum, containing numerous meibomian glands that empty into the ciliary border. The tarsus and conjunctiva form the inner linings of the lid 7. conjunctiva -- most posterior layer of the lid
Pre-operative Evaluation Physical Examination a. careful assessment of the full face including photo documentation and looking at skin type, pigmentation, wrinkles, lesions b. Proptosis - Forward projection or displacement of eye c. Ophthalmologic examination: visual acuity, extra-ocular muscle movement, fundoscopic exam, visual fields d. Schrimer test: assess tear production and identifies pts pone to dry eyes tab inserted between lids and eye closed gently for 5 minutes. Damp area measured (>10 mm is normal) e. Evaluation of lower lid i. Laxity of the lid can be evaluated by using 3 simple tests: 1. Snap test - grasp central portion of the lower lid between the index finger and thumb and pulling it forward and upward. With the lid under tension, it is released and allowed to snap back against the globe. An audible sound will be present if there is adequate elasticity of the upper lid 2. Retraction test is performed by placing the thumb or index finger in the central portion of the lid margin and retracting it inferiorly. This rotates the lower lid off the globe, which will test the laxity of the muscle and canthal ligaments when released. This response is usually slower than the snap test and should not be interpreted as abnormal unless retraction is incomplete or exceedingly slow. 3. Pinch test - central portion of the lid is grasped at the lid margin between the thumb and index finger and pinched together. If the apex of the lid margin is easily drawn from the globe for a distance of greater than 6 mm, this may represent excessive lid laxity. Contraindications: hypo/hyperthyroid, ptosis, dry eye Normal eye characteristics: Almond shaped lateral canthus slightly more superior than the medial canthus o typical superior elevations at the lateral canthus are 2 mm for men and 4 mm for women average palpebral opening is 10-12 mm in height and 28-30mm in width. The distance from the lateral canthus to the orbital rim is about 5 mm. The upper lid fold in Caucasians is approximately 8-11mm. The lower lid crease is about 5-6 mm. The high point of the brow is directed superiorly toward the lateral limbus. The upper eyelid margin normally crosses the cornea 2 mm inferior to the superior limbus. The distance from the supraorbital rim to the inferior aspect of the brow at the lateral limbus is about 10 mm in Caucasian women.
Steps of an upper lid blepharoplasty 1. Mark patient while patient is sitting upright. The lower incision is drawn first and should follow the natural lid crease. a. Pinch technique to determine amount of skin to excise 2. When the skin is removed, the fibers of the orbicularis will be seen. Usually a 2-3 mm strip of muscle is removed. 3. An incision is then made in the septum overlying the bulging fat. Only fat that easily protrudes with gentle pressure on globe should be removed. 4. Skin is then reapproximated. Two major approaches to lower blepharoplasty: 1. Transcutaneous a. Involves a subciliary incision through the orbicularis muscle down to the orbital rim. b. This skin muscle flap is elevated off the orbital septum c. The septum is then incised and excess fat removed. 2. Transconjunctival only addresses orbital fat, not lid skin a. Involves an incision in the lower lid conjunctiva, thus avoiding disruption of the orbicularis muscle. b. The dissection then proceeds along one of two routes: i. Preseptal approach -- placement of the incision high along the inside of the lower lid conjunctiva so that dissection proceeds anterior to the orbital septum and under the orbicularis ii. Retroseptal approach -- incision is placed 5 mm or more behind the tarsal plate. Fat compartments are entered directly after lower retractors are incised, and dissection takes place in the plane behind the orbital septum and orbicularis muscle. Some Complications of blepharoplasty: 1. Orbital hemorrhage and blindness a. Increases intraocular pressure and causes ischemic optic neuropathy due to occlusion of central retinal artery b. Symptoms rapid onset of pain, proptosis, eyelid ecchymosis c. Can perform lateral canthotomy for immediate decompression d. Need to return to OR for clot evacuation and hemostasis e. Blindness IV mannitol, steroids, ophtho consult 2. Ectropion a. Rotation of lid margin inferiorly with separation from globe b. Most common complication of lower bleph c. Occurs after excessive skin removal d. Requires surgical correction (horizontal lid shortening, muscle suspension, FTSG) 3. Milia - small subepidermal keratin cysts a. Most common complication of upper bleph. May be unroofed in office 4. Lagopthalmos inability to completely close eye a. Due to excessive skin resection or scarring b. May treat with lubrication, massage, taping or surgically with FTSG
Nose Functions of the nose are olfaction, respiration, filtration of dust, humidification of inspired air, reception of secretions from paranasal sinuses and nasolacrimal ducts External Nose Root: region between the 2 orbits Columella: inferior part of septum separating 2 nares Ala: wing of nose, lateral aspect of nose Vibrissae: short and thick bristle-like hairs that protrude from skin and are rich in sebaceous glands Skeleton is mainly cartilaginous. Dorsum extends from root to the apex of the nose. External Skeleton Bony skeleton consists of nasal bones, frontal process of the maxilla, and the nasal potion of the frontal bone and its nasal spine. The cartilaginous part of the nose consists of five main cartilages: 2 lateral cartilages, 2 alar cartilages, and a septal cartilage. Alar cartilages are free and mobile. Internal Nose: 1. Roof: cribiform plate (formed by nasal, frontal, ethmoid and body of sphenoid bones) and transmits CN 1 2. Floor: palatine process of maxilla and horizontal plane of palatine bone, contains incisive foramen transmits nasopalatine nerve and terminal branches of sphenopalatine artery 3. Medial Wall: Nasal septum vomer, perpendicular plate of ethmoid, septal cartilage 4. Lateral Wall: superior/middle/inferior conchae a. Contains these openings: i. Sphenoethmoidal recess: opening of sphenoid sinus ii. Superior meatus: opening of posterior ethmoidal air cells iii. Middle meatus: opening of frontal sinus into the infundibulum, middle ethmoidal air cells on the ethmoidal bulla, and anterior ethmoidal air cells and maxillary sinus in the semilunar hiatus iv. Inferior meatus: opening of nasolacrimal duct v. Sphenopalatine foramen: opening into the pterygopalatine fossa and transmits the sphenopalatine artery and nasopalatine nerve Blood Supply 4 major routes: 1. Ophthalmic artery anterior/posterior ethmoidal arteries (superior/middle meatus, midnasal septum) 2. Maxillary artery sphenopalatine artery posterior lateral nasal and posterior septal branches 3. Maxillary artery descending palatine artery greater palatine artery (lower part of nasal septum) 4. Facial artery lateral nasal branch superior labial artery septal branches
RHINOPLASTY Endonasal Approach 1. Anesthesia a. Endonasal b. Injection 3 surgical planes i. extraperiosteal plane ii. submucoperichondrial and submucoperiosteal spaces (hydraulic elevation of septal flap) iii. supraperichondrial and supraperiosteal regions over upper and lower cartilages and nasal bones just below subq tissues 2. Incisions and exposure a. Septoplasty i. Hemitransfixion incision- made through the mucosa on one side of the caudal septum to provide access for a septoplasty ii. Full transfixion incision- made through the mucosa on both sides just in front of the caudal septum to allow better access for repositioning and securing the septum to the nasal spine in patients in whom the caudal septum is dislocated off the premaxillary spine b. Rhinoplasty i. Bilateral intercartilaginous incisions- made between the alar and upper lateral cartilages and usually meet any transfixion incisions made ii. Alar marginal incisions- made at the lower margin of the alar cartilage if an endonasal tip delivery approach is desired c. Osteotomies i. Controlled fracture lines created by the surgeon to mobilize and reshape nasal bone segments into the form desired ii. Divided into: 1. Medial osteotomies -- aimed at mobilizing the medial aspect of the nasal osseous dorsum, usually performed first 2. Lateral osteotomies -- designed to fracture the lateral nasal osseous pyramid; Lateral osteotomies are initiated at the pyriform aperture or just above the attachment of the inferior turbinate to the ascending process of the maxilla in order to prevent inferior turbinate destabilization External Approach 1. Begins with bilateral incisions starting just anterior to the medial crura and extending from the dome to the midcolumellar region 2. Dissection extended to the septal angle and along the nasal dorsum tip to the caudal end of the nasal bones then the periosteum is lifted off nasal bones 3. Septoplasty can be performed especially helpful approach for pts with high septal deflection or in revision cases due to exposure