Congenital malformation of external ear and it’s management

Congenital malformations of external ear are the most common malformations presented to otolaryngologists and facial plastic surgeons. Hence in the pursuit of in-depth knowledge, a seminar on the topic was presented by me in the month of May 2017 at ENT-HNS dept, Silchar Medical College.

1. CONGENITAL MALFORMATIONS OF EXTERNAL EAR By Dr. Yousuf F. Choudhury PGT, ENT Dept Moderated By Dr. Shams Uddin Prof. HOD, ENT Dept. Silchar Medical College

2. APPLIED ANATOMY

3. Average adult female ear is 59 mm tall and the average male is 63mm tall. 85 % of height of ear is achieved by 3 years of age and almost 100% by 10 years of age. The size of ear remains the same size till the age of 60 when it gradually enlarges particularly the lobe. The average adult ear protrudes 19 mm from the mastoid skin

4. The long axis of the ear slopes backwards in line with the slope of the nose. The ear lies between the level of the eyebrow and a line of few millimetres beneath the nasal columella . The distance between the lateral canthus of the eye to the front of the ear is just over the length of the ear.

5. EMBRYOLOGY OF EAR

6. During the sixty week of intrauterine life the external ear begins to develop around the dorsal end of the first branchial cleft.  On either side of this cleft lie the first (mandibular) and second (hyoid) arches.  The auricle develops from these arches as 6 small buds of mesenchyme known as the six hillocks of His.  The first arch gives rise to the hillocks 1 to 3 and the second arch gives rise to hillocks 4 to 6.

7. There has been always a controversy regarding formation of which part of ear from which hillock. The auricle begins to develop in the anterior neck region, then it is postulated to migrate dorsally and cephalad as the mandible begins to develop during the second and third months of gestation.  By the 5th month of gestation the pinna lies in its adult location . HILLOCKS PART OF PINNA 1 ANTERIOR PORTION OF EAR LOBE 2 TRAGUS 3 ASCENDING HELIX 4 ANTI-HELIX 5 HELIX 6 POSTERIOR PORTION OF LOBE.

8. The external auditory canal begins to develop from the first branchial cleft during the first two months of gestation.  During the first month a solid epithelial cell rest forms in this area and is in contact with the endoderm of the first pharyngeal pouch.  There is an intervening mesoderm preventing direct contact between the ectoderm and endoderm

9. CONGENITAL DEFORMITIES OF EXTERNAL EAR

10. PRE-AURICULAR TAGS Very common Involves only skin but usually contains a long tail of cartilage extending into the cheek. Liga clip – tag drops off Vertical elliptical excision

11. MIRROR EAR OR POLYOTIA Persistent pre-auricular tissues lying on posterior cheek resembling extra ear. Skin is peeled off the extra- a uricular tissue, cartilage remnants trimmed & packed into anterior conchal hollow. Skin redraped to give cheek flatter shape

12. PRE-AURICULAR PITS AND SINUSES Often bilateral & frequently asymptomatic. Track deeply to facial nerve. Excision with facial nerve monitoring.

13. ABNORMAL FOLDS OF PINNA Common Lop ear - Upper pole of the ear flops over ‘ Mustarde ’ type suture used to create U-shaped cartilage prop at missing upper anti-helical fold. Ear hitched to the mastoid fascia Other varieties are – Kink of helical rim Abnormal fusion of helical rim to the anti-helical fold Whole ear appears collapsed vertically Surgical correction by scoring, tie-bar type tethering sutures or direct wedge excision

14. PROMINENT (‘BAT’) EARS Prominence is due to an absent anti-helical fold but in some cases, the conchal bowl is excessively deep Grading by Graham and Gault. Digital pressure on relevant part of ear determines cause and gauge strength of cartilage. Recommended to do surgery only after 5 years of age. Surgical techniques – anterior scoring, reshaping of the curves by the use of posterior sutures and excision techniques to set back the concha. Very challenging surgery

15. COLLAPSED EARS Scaphal hollow folded backwards to rest on conchal hollow. Surgical reconstruction by releasing the soft tissue tethering between scaphal and conchal cartilages and splinting these structures apart with a cartilage graft ( conchal hollow) FOLDED OVER HELICAL RIM Helical rim sharply folded over providing double layered in a single skin envelope, ear looks pinched. Folded over cartilage excised and then repositioned. Noonan Syndrome BUMPS Bump on helical rim Common Hillocks 3 & 4 irregular fuison

16. AURICULAR CLEFTS Groove or notch due to poor fusion of hillocks 6 & 1 In few, significant portion of lobe mission due to absence of hillock 6. Re-alignment of deep tissues with deep suture. UNDERDEVELOPED OR ABSENT LOBE Rebuilt around cartilage framework using conchal cartilage.

17. MACROTIA Excessively large ears. In normal ear, upper pole, conchal hollow and lobe take up an equal amount of the height of ear, splitting in to thirds. Big scaphal hollow or big lobe are the reasons of macrotia . Anterior crescent of skin and cartilage be removed from scaphal hollow. Wedge of tissue is removed from oversized lobe

18. CUP EARS Helical rim is constricted to give prominent, cone shaped ear. Difficult to correct. Several techniques used that include V-Y plasty , recnstruction using carved costal cartilage.

19. CRYPTOTIA ( ‘THE HIDDEN EAR’ ) Lower two thirds of ear visible, upper auricular sulcus seems lost. When ear is pulled away from the side of the head, the upper pole cartilage becomes evident, having hidden beneath scalp skin. Upper pole is tethered and lower lobe is prominent. Small ear buddies splint applied at birth for non-surgical correction. Later surgical correction by releasing the tethered portion of ear.

20. MICROTIA & CONGENITAL AURAL ATRESIA

21. DEFINITION Microtia : Defined as the abnormal development of the Pinna resulting in a malformed auricle . Congenital aural atresia: D efined as a failure of development of external auditory canal .   Congenital aural atresia is always associated with a certain degree of microtia .

22. EPIDEMIOLOGY Microtia and congential auditory atresia occur in approximately 1 in every 6000 live births.  These deformities commonly occur unilaterally, more so on the right side.  Men are affected thrice as common as women.  The degree of auricular deformity usually correlates with the degree of middle ear deformity.  The incidence of inner ear deformities are very rare in patients with congenital auditory atresia.   Microtia is associated with other anomalies of face 50% of the time.  Women with four or more pregnancies are at increased risk of  bearing a child with microtia .  The incidence of microtia is higher in Japanese population.

23. ETIOLOGY Exposure to teratogens like vitamin A, thalidomide, isotretinoin Vascular insults and genetic aberrations. Isolated microtia can occur with branchial arch anomalies. Syndromic associations of with congenital aural atresia include Goldenhar syndrome, mandibular facial dysostosis , brachio-otorenal syndrome Hemifacial microsomia Sticklers syndrome Crouzons syndrome Noonan syndrome Foetal Alcohol Syndrome CHARGE

24. PATHOGENESIS CONGENITAL AURAL ATRESIA At 28 weeks, a core of ectoderm canalizes from medial to lateral and eventually breaks through to communicate with the conchal depression. Failure of canalization or more rarely lack of ectodermal migration can lead to atresia of the external auditory meatus (EAM ) and partial canalization leads to meatal stenosis (an EAM with a diameter of less than 4 mm). Disruption of normal canalization or ectodermal migration can lead to arrested development of the tympanic ring mesoderm with the formation of a dense atretic bony plate in place of the tympanic membrane, an almost universal finding in canal atresia.

25. MICROTIA Malformation , such as anotia and microtia , are likely to be caused by the disturbance of development at seven to eight weeks gestational age, whereas deformations ( lop, cup and prominent ears) are caused by a problem later in the development or by external compression.

26. CLASSIFICATION Marx ‘s classification of external ear has proposed four descriptive groups which was later amended by Aguilar and Jahrsdoefer enabling the surgeon to categorize auricular deformity easily and into three grades. Altman gave anatomical classification of congenital aural atresia which was later modified by Marquet and Cremers . De la Cruz classification of congenital aural atresia based on HRCT scan is also used frequently by some surgeons.

27. GRADING OF MICROTIA ( MARX )

28. CLASSIFICATION OF AURAL ATRESIA GROUP DESCRIPTION Grade I TM hypoplastic . Tympanic bone is normal or hypoplastic . Ossicular malformation present but stapes is usually mobile Grade II Atretic plate present. Typanic bone is normal or hypoplastic . Tympanic cavity within normal limits. (In Marquet ’s modification, Course of facial nerve is normal in sub-type ‘ a ’ and is abnormal in sub-type ‘b’. In Cremer ’s modification, there is partial bony atresia in sub-type ‘a’ and total bony atresia in subt -type ‘b’) Grade III Above abnormalities may be found with a severely hypoplastic tympanic cavity.

29. DE LA CRUZ CLASSIFICATION HRCT based Mastoid Pneumatization Inner ear normality Facial nerve Footplate

30. DE LA CRUZ CLASSIFICATION Minor Malformations Normal mastoid pneumatization Normal oval window/footplate Good facial nerve–footplate relationship Normal inner ear

31. DE LA CRUZ CLASSIFICATION Major Malformations Poor pneumatization Abnormal or absent oval window/footplate Abnormal course of facial nerve Abnormalities of inner ear

32. MANAGEMENT Investigations : Age appropriate Hearing assessment HRCT Temporal bones X-ray Cervical spine USG for congenital renal malformations Panorex for malocclusion

33. Type Details Advantages Disadvantages Observation No Risk Appearance Prosthetic Adhesive retained Appearance Less secure attachment Ongoing prosthetic care Daily maintenance Use restrictions Implant retained Appearance Secure retention Multiple procedures Requires removal of remnant and soft tissue Ongoing prosthetic care Daily maintenance Use restrictions Reconstruction Rib Cartilage (Autogenous) Autogenous tissue Minimal maintenance Becomes sensate Atresia repair Inconsistent appearance Donor sites Multiple surgeries Reconstruction performed between 6 and 10 years of age Medpor Less donor site morbidity Less variability in carving Reconstruction performed at earlier age Foreign body More challenging to integrate with atresia repair OPTIONS FOR MICROTIA MANAGEMENT

34. MICROTIA RECONSTRUCTION WITH AUTOGENOUS CARTILAGE The technique was refined by Tanzer , father of Otoplasty . Tanzer surgery:  P erformed in four stages.  There is a three month gap between these stages. First stage:  Rib cartilage is harvested and sculptured into the shape of pinna and is placed under skin pocket of the microtic ear. Second stage: Formation of the lobule Third stage: Elevation of the ear with insertion of a post auricular skin graft Fourth stage:  Formation of the tragus with a skin/cartilage composite graft from the contralateral ear and full-thickness skin graft for the conchal area from the contralateral ear

35. Nagata technique:  This is a two staged procedure developed by Nagata.  This involves constructing the auricular framework form the sixth to ninth rib cartilages.  The framework is created using stainless steel sutures . There is six months gap between the two stages. Stage 1: Cartilage Implantation and Lobule Transposition Stage 2: Elevation of the Ear and Creation of Post-auricular Sulcus

36. COMPLICATIONS OF MICROTIA SURGERY MAJOR hematoma formation, skin flap necrosis, infection, and pneumothorax. MINOR malpositioning , scar contracture or hypertrophy, and poor contour.

37. MANAGEMENT OF CONGENITAL AURAL ATRESIA When associated with microtia , congenital aural atresia reconstruction may be undertaken before microtia reconstruction, after completion of all stages, or in combination with a stage of microtia repair. Historically, most authors advocate CAA repair to follow three stages of microtia reconstruction: cartilaginous auricular reconstruction, lobule rotation, and postauricular elevation and skin grafting . Currently, the optimal age to begin auricular reconstruction is generally considered age 7 years. For the occasional case of CAA without microtia and for CEACS, the atresiaplasty may be undertaken after the age of 4 years.

38. Jahrsdoefer et al. proposed a scoring system for the selection of patients with congenital aural atresia using a ten-point scale based on CT-scan elements and the appearences of external ear. Score 8-10 achieved post-operative SRT of 5-25 dB.

39. SCORING SYSTEM FOR CANDIDACY FOR SURGERY FOR CONGENITAL AURAL ATRESIA SCORE Stapes present 2 Oval window open 1 Middle ear space 1 Facial nerve 1 Malleus incus complex 1 Mastoid Pneumatization 1 Incus stapes connection 1 Round window 1 Appearance of external ear 1 Total availabl points 10

40. Prognostic Rating Scale 10 Excellent 9 Very good 8 Good 7 Fair 6 Marginal ≤5 Poor de Alarcon A, Jahrsdoerfer RA, Kesser BW. Congenital absence of the oval window: diagnosis, surgery, and audiometric outcomes. Otol Neurotol . 2008;29:23–28.

41. SURGICAL APPROACHES OF ATRESIAPLASTY Three possible approaches can be followed for congenital aural atresia repair.  They are: 1. Anterior 2. Modified anterior 3. Mastoid

42. ANTERIOR APPROACH Is the most common approach used these days.  In this approach a post auricular incision is made and the subcutaneous tissue and periosteum are raised anteriorly up to the level of glenoid fossa.  If any remnant of tympanic bone is present drilling is started at the cribriform area, and if no tympanic bone is present the drilling begins at the temporal line just posterior to the glenoid fossa.  Drilling is continued anteriorly and medially till epitympanum is entered.  The most common anamoly encountered in the middle ear of these patients is a fused malleal - incudal joint.  Stapes is usually normal in these patients. 

43. The atretic bone is carefully removed uncovering the ossicles .  The facial nerve usually lie medial to the ossicular mass, and must be protected at all costs. Drilling is continued till the canal is about 10mm in size.  Ossicular chain reconstruction is performed and a neo tympanum is fashioned using temporalis fascia graft.  Split thickness skin graft is used to line the external auditory canal.  A wide meatoplasty is fashioned and a large wick is inserted to stent the canal.

44. MODIFIED ANTERIOR APPROACH This approach is used in patients with a thick atretic plate because of poor orientation during dissection.  This poor orientation may risk carotid artery,  facial nerve, and lateral semicirular canal to injury.  Orientation in these patients could be achieved by an initial posterior dissection up to the level of sinodural angle.  This enables the surgeon to identify the level of lateral canal and ossicular mass.  From here on the approach is similar to that described under anterior approach

45. MASTOID APPROACH In this approach the external auditory canal is created at the expense of mastoid cavity.  It involves drilling out the mastoid and identifying the sino-dural angle.  This is a risky procedure because of distorted anatomy of the facial nerve in these patients.

46. COMPLICATIONS OF ATRESIAPLASTY Facial Nerve Inury – Transient or Permanent SNHL External auditory canal wall stenosis Lateralized tympanic membrane causing CHL Recurrent acute otitis, otitis media with effusion, retraction pockets, cholesteatoma, mastoiditis, chronic suppurative otitis media, tympanic membrane perforation, or any other disease of the ear

47. CONGENITAL EXTERNAL AUDITORY CANAL STENOSIS Congenital external auditory canal stenosis (CEACS ) is defined by Jahrsdoerfer et al . as an EAC with a diameter of less than 4 mm. A four level classification of CEACS was developed by Schuknecht . Meatal stenosis occurs as a result of partial lack of embryologic canalization of the EAC from the usual medial to lateral direction. Isolated meatal stenosis may be repaired, if severely narrow, via canaloplasty with drilling of the bony ear canal and thinning of the soft tissues with skin flap preservation.

48. ALTERNATIVES FOR CONGENITAL AURAL ATRESIA: IMPLANTABLE HEARING AIDS IN CHILDREN Several types of implantable hearing aids may be used for hearing rehabilitation of CAA in children over 5 years of age, as an alternative to atresiaplasty : percutaneous (crosses skin) bone-conduction devices (BAHA, Ponto), transcutaneous (closed-skin) bone-conduction devices ( Sophono ), and active middle ear implants (Vibrant Soundbridge ).

49. BAHA Was first described by Tjellström and colleagues. BAHA is considered the gold standard in terms of closure of the air-bone gap and the air-conduction PTA gain in children with CAA . The BAHA/Ponto may be useful for children with CAA who have unfavorable anatomy for reconstruction, those who are poor candidates for a lengthy atresiaplasty procedure for medical reasons, or for families that desire good hearing with less surgical risk. The standard surgical procedure includes the placement of a titanium fixture in the temporal bone with the reduction of the subcutaneous tissue and creation of a zone of alopecia around the abutment

50. The standard surgical procedure includes the placement of a titanium fixture in the temporal bone with the reduction of the subcutaneous tissue and creation of a zone of alopecia around the abutment The planned site for BAHA placement is 5.5 mm posterosuperior to the EAC or planned site of the EAC . It is 6.5 to 7.0 cm from the planned site of the EAC in ears with planned future microtia reconstruction, rather than the usual 5.5-cm distance.

51. The image of the BAHA shows how a button (or stud if you prefer) is inserted into the bone of the skull above the ear.

52. COMPLICATIONS OF BAHA SYSTEMS Bone Failure of osseointegration Chronic infection Trauma Soft tissue Irritation of the skin surrounding the implant Skin flap necrosis (death of the skin flap, e.g. due to interrupted blood supply) Overgrowth of skin over the device Wound dehiscence (splitting apart of the wound) Bleeding or hematoma formation Persistent pain

53. THANK YOU VERY MUCH