Reconstructive Procedures for Congenital Aural Atresia Harold F. Schuknecht, MD The three surgical methods currently in to improve hearing for patients with congenital aural atresia are fenestration of the lateral semicircular canal, canal plasty, and type III tympanoplasty. Because the surgery is difficult and the functional rewards are modest, it should ordinarily be reserved for patients with bilateral atresia. Of the 12 ears operated by the technique of type III tympanoplasty, the average gain in hearing was 22 dB, with seven attaining a 30 dB or better air-conduction threshold. When aural rehabilitative and cosmetic surgery are contemplated, coordinated planning by the surgeons is necessary to acquire the best end result. use
aural atresia, occurring in isolation, is a difficult surgical problem, but when it occurs in associ¬ ation with microtia or mandibulofacial dysostosis, the difficulties are compounded. Add to this the frequent parental desire for immediate and complete rehabilitation and we have a situation that may compromise good
Congenital
judgement. My observations regarding the for publication Aug 12, 1974. Read before the Tenth Annual Meeting of the American Academy of Facial Plastic and Reconstructive Surgery, Inc., Palm Beach, Fla, April 21, 1974. From the Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston. Reprint requests to the Massachusetts Eye and Ear Infirmary, 243 Charles St, Boston, MA 02114 (Dr. Schuknecht).
Accepted
state of the art, lead me to conclude that surgical methods cur¬ rently in use, both for cosmesis and for hearing rehabilitation, leave much to be desired. One cannot deny the oc¬ casional spectacular result, but aver¬ ages prove less rewarding. It seems probable, however, that new surgical methods to improve both hearing and cosmesis and, when approached by in¬ telligent coordinated planning, will provide more satisfactory results. The first question for any particu¬ lar case is whether cosmetic or hear¬ ing rehabilitative surgery is prudent; then, assuming that it is, which proce¬ dure should have priority, realizing that the first can compromise the suc¬ cess of the second.
present
and infection usually ensues (my per¬ sonal experience; also Hoenk et al2).
Type The external
Type I (Mild) A mild case is characterized by a small external auditory canal. The tympanic membrane is smaller than normal. The tympanic cavity may be normal in size or small, and the middle ear structures may show malformations of varying degree. Squamous epithelium may be trapped medial to a bony or fibrous atresia of the external auditory canal, leading to cholesteatoma. Unless the condi¬ tion becomes manifest and surgically corrected, the middle ear is invaded
(Medium)
auditory canal is ab¬
sent and the tympanic cavity is di¬ minished in size and its contents are deformed in varying degrees. The lat¬
eral wall of the tympanic cavity con¬ sists of an "atresia plate" that is ei¬ ther completely or partly osseous (Fig 1). The tympanic bone, if present, is deformed and plate-like. Sometimes it contains at its center a layer of con¬ nective tissue that is continuous with the connective tissue occupying the place of the missing external auditory canal. The malleus and incus are usu¬ ally deformed and fixed (Fig 2).
PATHOLOGIC FINDINGS
Altmann1 made a study of the ana¬ tomical features in 59 temporal bones with congenital aural atresia and de¬ veloped the following classification:
II
Type The external
III
(Severe)
auditory
canal is ab¬
sent, and the tympanic cavity is ei¬
ther very small or missing. The os¬ sicles are rudimentary or missing and the mastoid is not pneumatized. There frequently are associated anomalies of the inner ear. SURGICAL TECHNIQUES
Surgery for congenital aural atre¬ sia is one of the most difficult otologi¬ cal procedures and should not be per¬ formed by the occasional operator. There are three principal surgical methods for improvement of hearing in congenital aural atresia. These are: (1) fenestration of the lateral canal (Ombredanne3 * and Woodman5; (2) canal plasty (Shambaugh,* Guilford,7
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Fig 2.—Typical appearance of malleus and incus in a type II congenital atresia. Head of malleus is smaller than normal and attached to atresia plate by either bony fusion or fibrous fixation. Manubrium is missing. There is bony fusion of the incudomalleal articulation.
Fig 1—Horizontal
section
through temporal bone showing
and
House8; (3) type III tympano¬ plasty (Pattee9 and Ruedi10).
Fenestration of the lateral semi¬ circular canal has the advantage of requiring removal of only part of the atresia plate and of having rather predictable functional results (Fig 3). An air-bone gap of 15 to 20 dB is usual. Disadvantages are (1) a lab¬ yrinth fistula must be created, thus exposing the ear to a small risk of sensorineural deafness and (2) the mastoid must be widely exenterated, creating the possibility of a post¬ operative symptomatic mastoid cav¬ ity. The risk of the latter problem can be reduced by partial mastoid obliter¬ ation. The canal plasty procedure is more direct but somewhat more difficult be¬ cause of the more limited exposure to anatomical landmarks and greater dependence on successful skin graft¬ ing technique (Fig 4). Also, because all ossicles are preserved, the risk of the acoustic trauma from contact with the bur is greater. This ap¬ proach, however, causes less distur¬ bance of adjacent soft tissue and, therefore, favors subsequent surgery for microtia. In the most successful cases, a 10 dB air-bone gap can be achieved.
atresia
plate.
The type III tympanoplasty method requires surgical exposure of both the middle ear and mastoid (Fig 5). Because functional success de¬ pends on wide exposure of the stapes, the temporal bone should be well pneumatized and the atresia plate must be removed totally. The func¬ tional results are variable with airbone gaps ranging from 20 to 30 dB. If functional results are unsatisfac¬ tory, however, a fenestration of the lateral canal can be performed as a secondary procedure. The principal disadvantage is the postoperative mastoid cavity with its possible com¬ plications. The incidence of this prob¬ lem can be reduced, however, by oblit¬ eration of the cavity. There are risks and complications inherent to all three techniques. Among the most common of these are: (1) acoustic trauma from contact of burs with the ossicles; (2) facial nerve injury; (3) accidental surgical fistulization of the labyrinth; (4) post¬ operative stenosis of the newly cre¬ ated canal; and, (5) long-term or re¬ curring crusting and suppuration in the surgical cavity. Two of these, fenestration of the lateral canal and type III tympano¬ plasty to some extent compromise the
Removal of Small Part of Atresia Plate
Fig 3.—Fenestration of the lateral congenital aural atresia.
canal
for
of subsequent cosmetic sur¬ for microtia by reason of distur¬ gery bance of adjacent soft tissue. There¬ fore, if subsequent cosmetic surgery is contemplated, the canal plasty technique is probably the method of choice. success
RESULTS
My personal experience has been with the type III tympanoplasty tech¬ nique associated with mastoid obliter¬ ation. During the past ten years, the
operation
was
performed
on
12
ears
of eleven patients, five of whom were men and six women. There was asso¬ ciated microtia in seven, two of which had previous cosmetic surgery. Two of the ears had type I anomalies, the remaining ten ears being classified as type II.
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Obliteration of Mastoid
Malleus and incus
and
Epitympanum
Preserved
Split Thickness Skin Gì
Split
Thickness Skin Grafts
Removal of Most of Atresia Plate
Removal of Large Part of Atresia Plate
Fig
4.—Canal
plasty method
for
congenital
For the 12 ears, the average preop¬ erative bone-conduction threshold for the speech frequencies (500,1,000, and 2,000 hertz) was 9 dB and the air con¬ duction 55 dB. The average postoper¬ ative bone conduction was 7 dB and air conduction was 33 dB, giving an average gain of 22 dB and a postoper¬ ative air-bone gap of 26 dB. Seven of the 12 ears attained a 30 dB or better air-conduction threshold.
Congenital Atresia,
N-12
Microtia 30 dB or better threshold Stenosis Facial Palsy
7
Suppurating cavity Hearing loss (high tone)
0 1
7(58%) 7(58%) l(temporary)
Complications consisted of tempo¬ rary facial palsy (six weeks) in one case, stenosis of the newly created ca¬ nal requiring surgical correction in
ears, and a moderate senso¬ rineural hearing loss for high fre¬ quencies in one ear. None of the ears showed a loss of speech discrim¬ ination (PB-MAX). seven
COMMENTS The indications for surgery and the techniques to be used for the ear ex¬ hibiting both congenital aural atresia and microtia depend on the sex of the individual, whether one or both ears are involved, the state of pneu¬ matization of the temporal bones, and the skill and experience of the sur¬ geon. The surgery is difficult and the functional results are modest.
aural atresia.
Fig 5.—Type III tympanoplasty method for congenital aural
atre¬
sia.
My observations prompt me to sug¬ gest the following guidelines for the
selection of candidates for surgery: 1. Until better techniques become available, patients with unilateral au¬ ral atresia should not be subjected to hearing rehabilitative surgery be¬ cause the hearing gain usually will not adequately compensate for the ef¬ forts expended by the surgeon and the family, the physical and psycho¬
logical trauma to the patient, and the risk of surgical complications. 2. Until improved methods are de¬ veloped, female patients with micro¬ tia, either unilateral and bilateral, probably should not be subjected to
auricular cosmetic surgery because of the available alternative of conceal¬ ing the cosmetic defect. 3. The combination of aural rehabil¬ itative surgery and cosmetic surgery probably should be reserved for male patients with bilateral aural atresia and either unilateral or bilateral mi¬ crotia. 4. When both aural rehabilitative and cosmetic surgery are contem¬ plated, the surgeons should coordi¬ nate their efforts so that the first procedure will not compromise the success of the second. In these cases, the surgical method used for hearing improvement should be one that causes the least possible disturbance of adjacent tissue. In this regard, the canal plasty method has the theoreti¬ cal advantage. The surgery to im¬ prove hearing probably should be per-
formed
first, followed by an adequate postoperative observation period to insure against canal stenosis and cav¬ ity problems before cosmetic surgery is attempted. 5. The most appropriate age for au¬ ral rehabilitative surgery seems to be 5 or 6 years. When a child is capable of cooperating in postoperative care and before beginning primary school. References Congenital atresia of the ear in and animals. Ann Otol Rhinol Laryngol 64:824-858, 1955. 2. Hoenk B, McCabe B, Anson B: Cholestea¬ toma auris behind a bony atresia plate. Arch Otolaryngol 89:470-477, 1969. 3. Ombredanne M: Chirugie de la surdité: Fe¬ nestration dans les aplasies de l'oreille avec im¬ perforation du conduit; Résultats. Otorhinolar¬ yngol Int 31:229-236, 1947. 4. Ombredanne M: Thirty-three operations d'aplasie d'oreille avec impérforation du conduit auditif: Technique, constatations, opératoires et résultats. Acta Otolaryngol (Stockh) 41:69-109, 1952. 5. Woodman DG: Congenital atresia of the auditory canal: Two-stage operation with fenes¬ tration. Arch Otolaryngol 55:172-181, 1952. 6. Shambaugh G Jr: Developmental anomalies of the sound conducting apparatus and their sur¬ gical correction. Ann Otol Rhinol Laryngol 1. Altmann F:
man
61:873-887, 1952.
7. Guilford F: Discussion, remarks in, Congen¬ ital atresia of the auditory canal: Two-stage op¬ eration with fenestration by Woodman DG, pp 80-81. Arch Otolaryngol 55:172-181, 1952. 8. House H: Management of congenital ear ca¬ nal atresia. Laryngoscope 63:916-946, 1953. 9. Pattee G: An operation to improve hearing in cases of congenital atresia of the external auditory meatus. Arch Otolaryngol 45:568-580, 1947. 10. Ruedi L: The surgical treatment of the atresia auris congenita: A clinical and histologi¬ cal report. Laryngoscope 64:666-684, 1954.
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aural atresia, occurring in isolation, is a difficult surgical problem, but when it occurs in associ¬ ation with microtia or mandibulofacial dysostosis, the difficulties are compounded. Add to this the frequent parental desire for immediate and complete rehabilitation and we have a situation that may compromise good
Congenital
judgement. My observations regarding the for publication Aug 12, 1974. Read before the Tenth Annual Meeting of the American Academy of Facial Plastic and Reconstructive Surgery, Inc., Palm Beach, Fla, April 21, 1974. From the Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston. Reprint requests to the Massachusetts Eye and Ear Infirmary, 243 Charles St, Boston, MA 02114 (Dr. Schuknecht).
Accepted
state of the art, lead me to conclude that surgical methods cur¬ rently in use, both for cosmesis and for hearing rehabilitation, leave much to be desired. One cannot deny the oc¬ casional spectacular result, but aver¬ ages prove less rewarding. It seems probable, however, that new surgical methods to improve both hearing and cosmesis and, when approached by in¬ telligent coordinated planning, will provide more satisfactory results. The first question for any particu¬ lar case is whether cosmetic or hear¬ ing rehabilitative surgery is prudent; then, assuming that it is, which proce¬ dure should have priority, realizing that the first can compromise the suc¬ cess of the second.
present
and infection usually ensues (my per¬ sonal experience; also Hoenk et al2).
Type The external
Type I (Mild) A mild case is characterized by a small external auditory canal. The tympanic membrane is smaller than normal. The tympanic cavity may be normal in size or small, and the middle ear structures may show malformations of varying degree. Squamous epithelium may be trapped medial to a bony or fibrous atresia of the external auditory canal, leading to cholesteatoma. Unless the condi¬ tion becomes manifest and surgically corrected, the middle ear is invaded
(Medium)
auditory canal is ab¬
sent and the tympanic cavity is di¬ minished in size and its contents are deformed in varying degrees. The lat¬
eral wall of the tympanic cavity con¬ sists of an "atresia plate" that is ei¬ ther completely or partly osseous (Fig 1). The tympanic bone, if present, is deformed and plate-like. Sometimes it contains at its center a layer of con¬ nective tissue that is continuous with the connective tissue occupying the place of the missing external auditory canal. The malleus and incus are usu¬ ally deformed and fixed (Fig 2).
PATHOLOGIC FINDINGS
Altmann1 made a study of the ana¬ tomical features in 59 temporal bones with congenital aural atresia and de¬ veloped the following classification:
II
Type The external
III
(Severe)
auditory
canal is ab¬
sent, and the tympanic cavity is ei¬
ther very small or missing. The os¬ sicles are rudimentary or missing and the mastoid is not pneumatized. There frequently are associated anomalies of the inner ear. SURGICAL TECHNIQUES
Surgery for congenital aural atre¬ sia is one of the most difficult otologi¬ cal procedures and should not be per¬ formed by the occasional operator. There are three principal surgical methods for improvement of hearing in congenital aural atresia. These are: (1) fenestration of the lateral canal (Ombredanne3 * and Woodman5; (2) canal plasty (Shambaugh,* Guilford,7
Downloaded From: http://archotol.jamanetwork.com/ by a Indiana University School of Medicine User on 05/11/2015
Fig 2.—Typical appearance of malleus and incus in a type II congenital atresia. Head of malleus is smaller than normal and attached to atresia plate by either bony fusion or fibrous fixation. Manubrium is missing. There is bony fusion of the incudomalleal articulation.
Fig 1—Horizontal
section
through temporal bone showing
and
House8; (3) type III tympano¬ plasty (Pattee9 and Ruedi10).
Fenestration of the lateral semi¬ circular canal has the advantage of requiring removal of only part of the atresia plate and of having rather predictable functional results (Fig 3). An air-bone gap of 15 to 20 dB is usual. Disadvantages are (1) a lab¬ yrinth fistula must be created, thus exposing the ear to a small risk of sensorineural deafness and (2) the mastoid must be widely exenterated, creating the possibility of a post¬ operative symptomatic mastoid cav¬ ity. The risk of the latter problem can be reduced by partial mastoid obliter¬ ation. The canal plasty procedure is more direct but somewhat more difficult be¬ cause of the more limited exposure to anatomical landmarks and greater dependence on successful skin graft¬ ing technique (Fig 4). Also, because all ossicles are preserved, the risk of the acoustic trauma from contact with the bur is greater. This ap¬ proach, however, causes less distur¬ bance of adjacent soft tissue and, therefore, favors subsequent surgery for microtia. In the most successful cases, a 10 dB air-bone gap can be achieved.
atresia
plate.
The type III tympanoplasty method requires surgical exposure of both the middle ear and mastoid (Fig 5). Because functional success de¬ pends on wide exposure of the stapes, the temporal bone should be well pneumatized and the atresia plate must be removed totally. The func¬ tional results are variable with airbone gaps ranging from 20 to 30 dB. If functional results are unsatisfac¬ tory, however, a fenestration of the lateral canal can be performed as a secondary procedure. The principal disadvantage is the postoperative mastoid cavity with its possible com¬ plications. The incidence of this prob¬ lem can be reduced, however, by oblit¬ eration of the cavity. There are risks and complications inherent to all three techniques. Among the most common of these are: (1) acoustic trauma from contact of burs with the ossicles; (2) facial nerve injury; (3) accidental surgical fistulization of the labyrinth; (4) post¬ operative stenosis of the newly cre¬ ated canal; and, (5) long-term or re¬ curring crusting and suppuration in the surgical cavity. Two of these, fenestration of the lateral canal and type III tympano¬ plasty to some extent compromise the
Removal of Small Part of Atresia Plate
Fig 3.—Fenestration of the lateral congenital aural atresia.
canal
for
of subsequent cosmetic sur¬ for microtia by reason of distur¬ gery bance of adjacent soft tissue. There¬ fore, if subsequent cosmetic surgery is contemplated, the canal plasty technique is probably the method of choice. success
RESULTS
My personal experience has been with the type III tympanoplasty tech¬ nique associated with mastoid obliter¬ ation. During the past ten years, the
operation
was
performed
on
12
ears
of eleven patients, five of whom were men and six women. There was asso¬ ciated microtia in seven, two of which had previous cosmetic surgery. Two of the ears had type I anomalies, the remaining ten ears being classified as type II.
Downloaded From: http://archotol.jamanetwork.com/ by a Indiana University School of Medicine User on 05/11/2015
Obliteration of Mastoid
Malleus and incus
and
Epitympanum
Preserved
Split Thickness Skin Gì
Split
Thickness Skin Grafts
Removal of Most of Atresia Plate
Removal of Large Part of Atresia Plate
Fig
4.—Canal
plasty method
for
congenital
For the 12 ears, the average preop¬ erative bone-conduction threshold for the speech frequencies (500,1,000, and 2,000 hertz) was 9 dB and the air con¬ duction 55 dB. The average postoper¬ ative bone conduction was 7 dB and air conduction was 33 dB, giving an average gain of 22 dB and a postoper¬ ative air-bone gap of 26 dB. Seven of the 12 ears attained a 30 dB or better air-conduction threshold.
Congenital Atresia,
N-12
Microtia 30 dB or better threshold Stenosis Facial Palsy
7
Suppurating cavity Hearing loss (high tone)
0 1
7(58%) 7(58%) l(temporary)
Complications consisted of tempo¬ rary facial palsy (six weeks) in one case, stenosis of the newly created ca¬ nal requiring surgical correction in
ears, and a moderate senso¬ rineural hearing loss for high fre¬ quencies in one ear. None of the ears showed a loss of speech discrim¬ ination (PB-MAX). seven
COMMENTS The indications for surgery and the techniques to be used for the ear ex¬ hibiting both congenital aural atresia and microtia depend on the sex of the individual, whether one or both ears are involved, the state of pneu¬ matization of the temporal bones, and the skill and experience of the sur¬ geon. The surgery is difficult and the functional results are modest.
aural atresia.
Fig 5.—Type III tympanoplasty method for congenital aural
atre¬
sia.
My observations prompt me to sug¬ gest the following guidelines for the
selection of candidates for surgery: 1. Until better techniques become available, patients with unilateral au¬ ral atresia should not be subjected to hearing rehabilitative surgery be¬ cause the hearing gain usually will not adequately compensate for the ef¬ forts expended by the surgeon and the family, the physical and psycho¬
logical trauma to the patient, and the risk of surgical complications. 2. Until improved methods are de¬ veloped, female patients with micro¬ tia, either unilateral and bilateral, probably should not be subjected to
auricular cosmetic surgery because of the available alternative of conceal¬ ing the cosmetic defect. 3. The combination of aural rehabil¬ itative surgery and cosmetic surgery probably should be reserved for male patients with bilateral aural atresia and either unilateral or bilateral mi¬ crotia. 4. When both aural rehabilitative and cosmetic surgery are contem¬ plated, the surgeons should coordi¬ nate their efforts so that the first procedure will not compromise the success of the second. In these cases, the surgical method used for hearing improvement should be one that causes the least possible disturbance of adjacent tissue. In this regard, the canal plasty method has the theoreti¬ cal advantage. The surgery to im¬ prove hearing probably should be per-
formed
first, followed by an adequate postoperative observation period to insure against canal stenosis and cav¬ ity problems before cosmetic surgery is attempted. 5. The most appropriate age for au¬ ral rehabilitative surgery seems to be 5 or 6 years. When a child is capable of cooperating in postoperative care and before beginning primary school. References Congenital atresia of the ear in and animals. Ann Otol Rhinol Laryngol 64:824-858, 1955. 2. Hoenk B, McCabe B, Anson B: Cholestea¬ toma auris behind a bony atresia plate. Arch Otolaryngol 89:470-477, 1969. 3. Ombredanne M: Chirugie de la surdité: Fe¬ nestration dans les aplasies de l'oreille avec im¬ perforation du conduit; Résultats. Otorhinolar¬ yngol Int 31:229-236, 1947. 4. Ombredanne M: Thirty-three operations d'aplasie d'oreille avec impérforation du conduit auditif: Technique, constatations, opératoires et résultats. Acta Otolaryngol (Stockh) 41:69-109, 1952. 5. Woodman DG: Congenital atresia of the auditory canal: Two-stage operation with fenes¬ tration. Arch Otolaryngol 55:172-181, 1952. 6. Shambaugh G Jr: Developmental anomalies of the sound conducting apparatus and their sur¬ gical correction. Ann Otol Rhinol Laryngol 1. Altmann F:
man
61:873-887, 1952.
7. Guilford F: Discussion, remarks in, Congen¬ ital atresia of the auditory canal: Two-stage op¬ eration with fenestration by Woodman DG, pp 80-81. Arch Otolaryngol 55:172-181, 1952. 8. House H: Management of congenital ear ca¬ nal atresia. Laryngoscope 63:916-946, 1953. 9. Pattee G: An operation to improve hearing in cases of congenital atresia of the external auditory meatus. Arch Otolaryngol 45:568-580, 1947. 10. Ruedi L: The surgical treatment of the atresia auris congenita: A clinical and histologi¬ cal report. Laryngoscope 64:666-684, 1954.
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