------------------------------------------------------------------------------- TITLE: SURGERY OF THE EXTERNAL CANAL AND AURICLE SOURCE: Dept. of Otolaryngology, UTMB, Grand Rounds DATE: November 15, 1989 RESIDENT PHYSICIAN: Jeff S. Chimenti, M.D. FACULTY: Chester L. Strunk, M.D. DATABASE ADMINISTRATOR: Melinda McCracken, M.S. ------------------------------------------------------------------------------- "This material was prepared by resident physicians in partial fulfillment of educational requirements established for the Postgraduate Training Program of the UTMB Department of Otolaryngology/Head and Neck Surgery and was not intended for clinical use in its present form. It was prepared for the purpose of stimulating group discussion in a conference setting. No warranties, either express or implied, are made with respect to its accuracy, completeness, or timeliness. The material does not necessarily reflect the current or past opinions of members of the UTMB faculty and should not be used for purposes of diagnosis or treatment without consulting appropriate literature sources and informed professional opinion." I. Anatomy A. Auricle 1. General features a. elastic fibrocartilage covered by perichondrium and skin; concave lateral surface-skin firmly adherent to perichondrium; convex medial surface-skin loosely attached b. firmly attached to tympanic bone; more loosely attached to anterior, superior, and posterior auricular ligaments 2. Anatomic structures a. crus of helix-divides concha into cymba conchae superiorly and cavum conchae inferiorly; cavum conchae extends into cartilaginous canal b. incisura terminalis-incomplete portion of superior cartilaginous canal c. tragus-prominent cartilaginous process inferior to incisura d. antitragus-inferior and opposite tragus e. antihelix-posterosuperior rim of conchal cartilage; forms two ridges which define triangular fossa f. helix-external rim of auricle; continuous with crus superiorly and lobule inferiorly (devoid of cartilage) B. External auditory canal 1. General features a. lateral portion (30-40%) cartilaginous; medial portion (60-70%) osseus b. 25mm long and S-shaped with narrowest portion (isthmus) just medial to bony-cartilaginous junction c. TM oblique orientation in EAC-anterior/inferior walls 6mm longer than posterior/superior walls 2. Cartilaginous canal a. courses rostral and posterior; incomplete posteriorly and superiorly b. fissures of Santorini-anterior wall slits/dehiscences-possible spread of infection into periauricular soft tissue, parotid, glenoid fossa 3. Osseus canal a. courses anterior and inferior b. skin devoid of subcut. layer, hair follicles, sebaceous/apocrine glands c. superior wall-medially, thin bone (scutum) separates from attic of tympanic cavity; laterally, thicker bone separates from middle fossa d. posterior wall-close to mastoid cells/descending facial canal e. inferior wall-usually dense bone, may be thin with dehiscent jugular bulb f. anterior wall-posterior limit of glenoid fossa (close to condyle of mandible) C. Nerve supply, Blood supply, Lymphatics 1. Nerve supply a. greater auricular (from C2 and C3)-skin of mastoid, medial/lateral pinna b. auriculotemporal (from CN5)-cartilaginous/bony meatus, ant. pinna c. auricular branch (CN10)-floor of EAC, small portion of auricle d. CN7 branches and CN9 branches- posterior/superior EAC 2. Blood supply a. external carotid (1) posterior auricular-mastoid/auricle region (2) superficial temporal-EAC/auricle 3. Lymphatics a. inferior EAC-infraauricular LN's b. posterior EAC-postauricular LN's c. ant./sup. EAC-preauricular LN's d. antihelix/concha-mastoid apex LN's e. sup. auricle-postauricular LN's II. Congenital Auricle Malformations A. Prominent ear 1. General considerations a. protruding--when angle between dorsal surface of upper helical rim and mastoid plane is greater than 40 degrees; angle normally increases until adolescence b. deformity results from failure of antihelical folding with flattening of superior crus and possibly inferior crus c. conchal enlargement may contribute in severe cases 2. Evaluation a. fold ear manually and if normal shape/size correct protrusion only; large ear-reduction of size, concha b. large, protruding concha-partial excision of conchal cartilage 3. Surgical principles a. correct usually prior to school age b. weaken cartilage along antihelical fold-- diamond burr or multiple parallel cuts c. Mustarde's suture technique (modified) (1) postauricular crease incision with skin elevation and cartilage exposure (2) bend ear to identify correct suture placement (3) insert 3-0 mattress sutures (child-3, adult-4 to 5) and tighten beginning with middle suture with just enough tension to produce normal protrusion; *most difficult step (4) possible reduction of concha d. conchomastoid sutures-protruding concha e. reduction of postauricular skin and suture to periosteum of mastoid (avoids dead space, scar stabilizes surgery) f. if lower 1/3 still protrudes, excise strip of postauricular skin to correct g. measure distance from mastoid plane and correct opposite side similarly h. light pressure dressing several days; no drains; sutures x2 weeks; ski band at night x3 months B. Cup ear (constricted or lop ear) 1. General considerations a. upper/middle portions anomalous with upper portion bent forward and downward (hooding) with insufficient skin/cartilage and tightened helical rim b. conchal prominence; vertical dimension reduced; severe cases-upper portions missing 2. Surgical principles a. No shortage of cartilage/skin (1) postauricular crease incision with undermining to rim of helix; avoid cartilage incisions (sharp surfaces on ant. surface) (2) Mustarde's suture technique-mattress sutures for upper auricle; conchomastoid sutures (3) posterior surface skin to close upper auricle defect b. Shortage of cartilage/skin (severe) (1) 1st stage--mark ear with normal template; postauricular crease incision extending through cartilage of crus; transposition flap-crus of helix, postauricular skin; cochomastoid sutures; possible mattress sutures (2) 2nd stage--autogenous cartilage implant for upper deficiency (as in microtia) C. Cryptotia (pocket ear) 1. General considerations a. upper ear adheres to mastoid with no space between ear and skull b. prevalent in orientals, rare in caucasian or blacks 2. Surgical principles a. upper ear dissected away from skull and protruding position established b. correct cartilage deformity-mattress sutures c. hairless postauricular skin flap advanced to cover post. surface of auricle d. hair bearing skin advanced anteriorly to close postauricular defect e. suture postauricular skin flap to periosteum not to hair bearing skin (prevents recurrence) D. Large/Small auricles 1. Large auricle a. deformity rare; usually associated with hemifacial hypertrophy b. surgery-2 stages (better results): 1st reduce size then later reduce prominence c. reduce size (1) must also create helix/antihelix which are usually absent (2) star-like excision--reduces size and gives definition of helix (3) excision of portion of auricle between helix/antihelix and portion of helix 2. Small auricle a. no surgery if difference in size is not readily apparent b. best to reduce size of larger auricle c. if markedly smaller-increase size using composite graft of skin/cartilage from concha of normal auricle and insert into conchal defect created in small auricle E. Microtia 1. General considerations a. hypoplasia of auricle often associated with atresia of EAC b. most frequently rudimentary auricle with longitudinal skin fold including remnant cartilage with lower portion better developed c. lobule usually present-used in reconstruction; remnant cartilage useless d. often component of hemifacial or bilateral microsomia (1st and 2nd brachial arch syndrome); reconstruct facial skeleton and soft tissues prior to auricle 2. Timing a. reconstruct between ages 6-8 yrs. b. no substantial growth of auricle past age 8; 7/8 of mature size at age 6 c. may reconstruct lobule earlier d. must consider later auricle reconstruction at the time of canal atresia repair--meatus should not be placed too close to hairline 3. Planning a. determine amount/quality of tissue available b. other facial deformities present c. facial nerve may be close to deformed cartilage d. creation of lobule prior to or following implant insertion--usually prior to insertion because less chance of implant exposure and facilitates further reconstruction e. location of hair line--need hairless skin to cover implant f. scarring of adjacent tissue (burn, trauma, surgery)-replace with full thickness skin graft 4. Choice of implant a. Autogenous rib graft (most popular) (1) advantages--good long term, tissue accepts well with little reaction, little resorption (viable chondrocytes) (2) disadvantages--young children (<6 ) have little rib cartilage so delay in reconstruction, pleural injury, lacks elasticity b. Allografts (polyurethane, polyester, dacron, silastic) (1) silastic recommended; prepare from plaster cast of normal ear; stainless steel reinforcement of 3-D shape (2) advantages--good elasticity, no delay in reconstruction, no second procedure to obtain cartilage (3) disadvantages--infection more common with implant exposure, tissue reaction to implant material 5. Surgical stages a. lobule construction/remnant removal (1) template of normal ear on translucent radiograph to outline auricle position (2) transposition flap with lower portion of folded auricle moved laterally to reach normal ear contour and other triangle moved medially to fill defect; remove remnant cartilage to form depression (caution: facial nerve) (3) midportion skin fold-reconstruct tragus (4) massage of skin/scars-softens, improves circulation (5) perform at age 2-3 yrs. b. implant insertion (1) template to define normal contours (2) semicircular incision above hairline with skin undermining to lobule (3) insert implant with lower end into lobule; sutures to stabilize (4) pressure dressing (5) autogenous rib cartilage: incision over 6th interspace, elevate perichondrium and dissect cartilage from synchondrosis (6th, 7th ribs) using template, 8th rib cartilage to create helix c. ear positioning (different techniques) (1) full thickness skin graft to posterior surface after dissection of implant; create deep postauricular crease with foam rubber bolsters/through and through mattress sutures (disadvantage--scar contracture with loss of protrusion) (2) 3-D illusion--exaggerate helix height/conchal depth (3) rolled skin flap--1st step: undermine/roll-up hair bearing skin, cover defect with full thickness graft, vigorous massage of skin graft 2nd step: 3-4 months later, former full thickness graft undermined to form flap to cover posterior surface of implant after dissection of implant, hairbearing skin unrolled to fill defect, both flaps sutured to periosteum 6. One stage reconstruction a. use if enough tissue to create lobule and cover posterior auricle surface; if fails simply proceed to multi-stage procedure b. incise anterior edge of skin fold and unfold to create lobule and posterior implant bed c. insert implant, secure in place, and cover anterior surface with preauricular flap or full thickness graft III. Acquired Auricle Malformations and Trauma A. Partial/Total auricle defects 1. Partial defects a. options include: local flaps, implants, or size reduction b. if cartilage lost but no soft tissue-use autogenous implant c. usually suture edge of defect to postauricular skin by creating linear wound; 4-6 wks. later, postauricular skin marked with template and local flap used to cover posterior surface of defect (pedicle transposition or rotation advancement) 2. Total defects a. similar principles to microtia b. if severe scarring (burns, trauma)-replace tissue with full thickness graft; massage 2-3 mos. then implant insertion c. if ablative surgery for cancer-delay reconstruction 1 yr. d. tube pedicle flap-severely damaged tissue; donor site often subclavicular area (ipsilateral); "train" pedicle with occlusion by penrose drains; often defatting needed; local skin flap should be 1st option over tube pedicle flap B. Lacerations/Avulsions of auricle 1. Lacerations a. preserve all viable tissue with minimal debridement b. primary reattachment suggested with all partial avulsions (even with narrow pedicle) 2. Avulsions a. occasionally complete reattachment successful b. favorable factors: clean laceration with few abrasions/contusions, 2-3 hrs. from injury, no contraindications to heparinization c. unfavorable factors: severe auricle injury, greater than 6 hrs. from injury, other injuries contraindicating heparinization d. detached auricle--clean with cold saline, place in heparinized antimicrobial solution in ice container e. surgery (1) favorable-primary reattachment, pie- crusting,heparinization (2) unfavorable-pocket principle: strip skin from cartilage and insert beneath postauricular skin and later reconstruct C. Hematoma/Cauliflower ear deformity 1. Hematoma a. blunt trauma (wrestlers, boxers) creates shearing force which disrupts adherence of perichondrium to cartilage; subperichondrial space hematoma deprives cartilage of nutrients b. treatment: prevent cauliflower ear; aspiration with pressure dressing (often incomplete); best to incise over hematoma, evacuate, irrigate, and place through and through sutures tied to dental rolls on anterior/posterior auricle surface, remove in one week 2. Cauliflower ear a. prevention is best (see above) b. treatment: surgical removal of fibrosed tissue to improve auricle contour D. Keloid of auricle 1. Commonly after ear piercing, surgery, trauma 2. Treatment: surgical excision with subsequent steroid injections; pre-op/post-op irradiation (600-800 rads) noted to have good success E. Split ear lobule 1. Occurs with large, heavy earrings 2. Treatment: excision of scar with primary reapproximation IV. Congenital Atresia of External Auditory Canal A. Embryology 1. Ossicles-1st and 2nd branchial arches (except stapes foot plate); external canal/TM-1st branchial cleft; branchial cleft (external canal) and branchial arch malformations often together 2. Membranous labyrinth-ectodermal otocyst; stapes foot plate-forms with otic capsule (usually normal) 3. Eustacian tube, middle ear, mastoid-1st branchial pouch B. Classification system (Altman-modified) 1. Group 1 (minor aplasia)-meatus and TM small, ossicles usually fixed, stapes usually abnormal, simple transcanal surgery, good results 2. Group 2 (moderate aplasia)-pinna severely deformed, external canal absent, numerous middle ear anomalies 3. Group 3 (severe aplasia)-absent EAC, poor pneumatization of mastoid, often cochlear anomalies C. Anatomic considerations 1. External canal/middle ear a. absent EAC so TMJ displaced posteriorly with glenoid fossa directly contacting anterior wall of mastoid tip (just lateral to middle ear) b. atresia more commonly bony than membraneous and severe auricle malformations usually associated with atresia 2. Facial nerve a. with hypoplastic tympanic bone descending portion of facial nerve forms an acute angle at 2nd genu to exit in glenoid fossa; commonly lateral/anterior displacement of descending portion b. may obscure oval and round windows; may have bony dehiscence of fallopian canal 3. Ossicular chain a. malleus often fused with incus; long process of malleus often absent b. bony atresia usually associated with malformed ossicles 4. Inner ear a. abnormalities in 15-20%, SHNL-5-10% D. Patient evaluation 1. Exam a. palpate TMJ, condyle, mastoid tip b. severity of auricle deformity, type of canal remnant (blunt opening-no tympanic bone; pinpoint opening-partial tympanic bone) 2. Audiometry a. ABR--use in newborns to assess cochlear response in normal ear; bone conduction oscillator for bilateral atresia b. conventional audiometry--older children and adults 3. Radiography a. perform CT scan at age 4-5 yrs. unless complication require earlier scan b. assess pneumatization of temporal bone, course of facial nerve, existence of oval window and stapes foot plate, status of inner ear (polytomography also useful) c. lack of pneumatization primary cause of inoperability E. Management before surgery 1. Unilateral atresia-establish adequate hearing in normal ear 2. Bilateral atresia-establish cochlear reserve then fit for hearing aid ASAP; bone conduction aid if no canal remnant F. Surgical correction 1. Precedence a. unilateral atresia with normal opposite ear-- auricle reconstruction 1st, atresia reconstruction in adulthood b. bilateral atresia--restore hearing prior to auricle reconstruction 2. Surgical procedure--Anterior (transatretic) Approach vs. Mastoid Approach a. Anterior Approach (1) incision: postauricular to expose mastoid, elevate soft tissue anteriorly to TMJ to locate tympanic bone (2) drill new canal: use middle cranial fossa dura as superior landmark and TMJ as anterior landmark, expose malleus/incus in epitympanum (facial n. medial to ossicular mass) (3) remove atretic bone: thin bone with diamond burr and remove with small hook, avoid drilling/manipulation of ossicular chain (caution: facial nerve may lie lateral to middle ear at inferior/posterior portion of atretic plate); expose entire middle ear (4) middle ear surgery: best to leave ossicular chain intact rather than using prosthesis (5) TM grafting: fascia graft tucked beneath anterior/superior bony ledges of canal wall; may need to drill out ledge (6) meatoplasty: undermine auricle and debulk soft tissue around meatus (2x normal size); often reposition auricle post./sup. with excision of strip of postauricular tissue (caution: facial nerve nearby) (7) skin grafting: STSG obtained, measure EAC dimensions, overlap fascia graft 1-2mm, cortisporin/gelfoam over fascia graft and layer nu-gauze/antibiotic ointment into bony canal, suture lateral STSG to meatal opening, 2nd layer nu- gauze (8) post-op care: remove nu-gauze 10 days, cortisporin/gelfoam to fill canal-remove in 4 wks. (9) advantages: avoid mastoid cavity-debris accumulation, infection; less manipulation in area of descending facial n.; simple contours of new canal facilitate placement of STSG (10) facial nerve monitoring during surgery with EMG b. Mastoid Approach--sinodural angle 1st identified and followed to mastoid antrum; facial recess opened and incudostapedial joint separated 3. Unilateral atresia a. usually do not correct until adulthood if patient desires surgery b. problems in children: usually unappreciative of hearing gain, requires cleaning and frequent F/U, possible complications 4. Bilateral atresia a. 1st surgery age 4-5 yrs. b. correct 2nd ear in 6-9 mos. c. probability of hearing gain off-sets possible complications G. Complications 1. Infection and Cholesteatoma a. mastoid/middle ear infections possibly masked by atretic canal b. cholesteatoma (5%)-form in partially formed external canals with trapped epithelium (consider especially in pinpoint canal with intermittent drainage) c. reconstructed ear-otitis media as in normal ear; graft may break down over mastoid cell and if no response to antibiotic then revision of canal 2. Stenosis a. incidence as high as 40% in some studies b. reduce likelihood: large meatus created, large canal, STSG to cover canal, prevent post-op infection, steroid injections if tendency for keloid or scar formation, avoid hard stents (irritation), if beginning to stenose use soft stent and steroid injection 3. Hearing loss a. SNHL--can occur with excess manipulation of ossicular chain (contact with drilling burr) b. CHL--if ossicles touching new bony canal, fallopian canal; external migration of TM (primary cause of hearing failure) 4. Facial nerve injury--prevent with use of facial nerve monitor (EMG) and by use of caution during middle ear surgery/raising flaps around auricle V. Acquired Stenosis of External Auditory Canal A. Cause: traumatic, infectious/inflammatory, neoplastic, surgical B. Surgical Technique 1. McDonald, et al., 1986 reported a series of 22 patients with only 2 restenoses and 2 mild narrowings in a 3 yr. follow-up 2. Incision of stenotic meatus including generous portion posteriorly followed by postauricular incision with forward traction of pinna and dissecting out stenotic meatus (excise through and through wedge of conchal skin/cartilage) 3. Dissect skin from cartilaginous/bony wall 4. Goodhill instrument to loosen skin and deep canal and remove epithelial layer from TM 5. Widen posterior bony canal with cutting burr until mastoid cells just encountered 6. Two separate STSG's harvested-1 attached to anterior margin, 1 attached to posterior margin of meatus and placed along bony canal with almost complete coverage of TM 7. Two strips of silastic placed in ear canal and cortisporin/iodoform gauze to fill canal--remove packing 3 wks., silastic 4 wks. C. Key Steps: 1. wide meatoplasty 2. remove all infected canal skin (including TM) 3. widen posterior canal wall (most important step) 4. apply 2 separate STSG's secured by silastic 5. soft packing x4 wks. D. Other Techniques 1. Moore, et al., 1984--used full thickness skin graft with glandular elements present and reported less contraction of skin graft 2. Lamas, et al., 1988--CO2 laser excision of stenotic area with adjacent pedicle flaps for covering site 3. Bell, 1987--reported series of 10 cases with no restenoses using dual flap technique with superiorly based anterior flap rotated into endaural incision and inferiorly based posterior flap fed through posterior external canal wall leaving permanent fistula in post. skin crease VI. Infections A. Intractable External Otitis 1. Chronic inflammatory stage--canal skin thickened with hyperkeratosis, eczematous changes, loss of normal skin appendages and cerumen 2. Treatment--initially steroid drops, may take mos. for regrowth of skin appendages; if medical treatment not effective, then perform meatoplasty/canaloplasty (see surgical technique in acquired stenosis); also applies to keratosis obturans B. Necrotizing External Otitis 1. Elderly diabetics with granulation tissue in canal and relentless pain 2. Treatment--surgical debridement of EAC (debris, granulation tissue, cartilaginous sequestra), anti- pseudomonal drops, systemic antibiotics, HBO 3. Subtemporal abscess (infected soft tissue at skull base) sometimes present if unresponsive to medical management-requires subtotal temporal bone resection VII. Neoplasms A. General Considerations 1. Squamous cell carcinoma--most common malignant tumor, predilection for helix 2. 6% of all skin malignancies B. Auricle 1. Surgical techniques a. wedge excision/stellate excision--1 stage closure but decreases size (poor cosmesis with large lesions) b. postauricular advancement flap--2 stage reconstruction c. through and through excision with primary closure--anterior surface lesions not involving helical rim d. helical advancement--superior helical lesions e. auriculectomy and STSG--best for large tumors involving most of pinna 2. Indications for neck dissection: 1. tumor >4cm diameter 2. cartilage invasion 3. depth of growth equivalent to Clark's level 5; large tumors may require modified temporal bone resection and radical neck dissection C. External Auditory Canal 1. Symptoms--pain, bloody discharge; prognosis worse than auricle lesions 2. Treatment--wide excision for small lesions; if bone invasion or LN's positive or soft tissue spread, then excise entire EAC with modified temporal bone resection, radical parotidectomy, neck dissection 3. Poor prognosis: facial n. involvement, recurrent locally, incomplete excision, inadequate XRT D. Selected Lesions 1. Basal cell carcinoma--no predilection for helix; can be aggressive in EAC; treatment with surgical excision, Mohs chemosurgery, electrodessication 2. Malignant Melanoma--prognosis mainly related to microscopic thickness of lesion and presence of involved LN's; also depth of invasion 3. Bony Neoplasms (Osteomas or Exostoses)--surgery if obstructing canal, recurrent external otitis, CHL; treatment--elevate skin off lesion and drill or chisel deformity -------------------------------------------------------------------- BIBLIOGRAPHY 1. Cummings, C.W.; Otolaryngology-Head and Neck Surgery (Vol. 4); The CV Mosby Company, 1986. 2. Jahrsdoerfer, R.A.; Congenital atresia of the ear; Laryngoscope; 88:1, 1978. 3. Glasscock, M.E., et al; Management of congenital ear malformations; Ann. Otol. Rhinol. Laryngol.; 92:504, 1983. 4. Crabtree, J.A.; Congenital atresia: case selection, complications, and prevention; Otolaryngol. Clin. North Am.; 15:755, 1982. 5. Bardach, J.; Reconstruction of the microtic auricle in a four stage operation; ORL; 78:349, 1974. 6. Clemens, J.E., and Connelly, M.V.; Reattachment of a totally amputated auricle; Arch. Otolaryngol.; 97:269, 1973. 7. Mattox, D.E., and Fisch, U.; Surgical correction of congenital atresia of the ear; Otolaryngol. Head Neck Surgery; 94:574, 1986. 8. De la Cruz, A., et al; Congenital atresia of the external auditory canal; Laryngoscope; 95:421, 1985 9. Paparella, M.M.; Surgical management of intractable external otitis; Laryngoscope; 76:1136, 1966. 10. Raines, J.M., and Schindler, R.A.; The surgical management of recalcitrant malignant external otitis; Laryngoscope; 90:369, 1980. 11. Mladick, R.A., et al; The pocket principle: a new technique for the attachment of a severed ear part; Plast. Reconstr. Surg.; 48:219, 1971. 12. Conley, J., and Schuller, D.E.; Malignancies of the ear; Laryngoscope; 86:1147, 1976. 13. Bell, D.R.; External auditory canal stenosis and atresia: dual flap surgery; J. Otolaryngol.; 17:19, 1988. 14. McDonald, T.J.; Surgical treatment of stenosis of the external auditory canal; Laryngoscope; 96:830, 1986. 15. Lambert, P.R.; Major congenital ear malformations: surgical management and results; Ann. Otol. Rhinol. Laryngol.; 97:641, 1988. 16. Jarsdoerfer, R.A.; Surgical correction of congenital atresia; 17th Annual Otolaryngology Conference--Otology Update; Galveston, Tx., 1986. 17. Moore, G.F., et al; Use of full thickness skin grafts in canalplasty; Laryngoscope; 94:1117, 1984. 18. Lamas, G., et al; Treatment of acquired stenosis of the external auditory canal; Ann. Otolaryngol. Chir. Cervicofac.; 105:271, 1988. ----------------------------END----------------------------------------