- Email: [email protected]
Reconstruction of the ossicular chain in children
Operative Techniques in Otolaryngology (2009) 20, 187-196
Reconstruction of the ossicular chain in children Amy C. Brenski, MD, Brandson Isaacson, MD From the Department of Otolaryngology Head and Neck Surgery, Division of Pediatric Otolaryngology, Division of Neuro-Otology, University of Texas-Southwestern, Dallas, Texas. KEYWORDS Ossicular chain; Ossiculoplasty; Incus interposition; Prothesis; Incus transposition
Ossiculoplasty in pediatric patients presents several unique surgical challenges. A conservative approach includes establishing a safe, well-aerated middle ear with an intact tympanic membrane before attempting reconstruction of the ossicular chain. However, a more aggressive approach with immediate ossicular reconstruction may be indicated in certain clinical situations. Close monitoring during postoperative healing is important to achieve and maintain a good hearing result. However, successful ossicular reconstruction can be achieved in children. It may have a more important role in children given the importance of binaural hearing in speech and language development and success in education. In this article, the authors describe their operative approach to reconstruction of the ossicular chain in children. Published by Elsevier Inc.
The result of chronic otitis media and cholesteatoma in children is often conductive hearing loss due to tympanic membrane perforation and/or erosion of the ossicular chain. More commonly, chronic suppurative otitis media through a chronic tympanic membrane perforation results in erosion of the ossicular chain over time and subsequently hearing loss. A less frequent cause of conductive hearing loss is trauma to the temporal bone or middle ear causing disruption of the ossicular chain. Ossiculoplasty is a reasonable option for the restoration of hearing in children. However, there are special considerations in the pediatric population. A stable, central, dry tympanic membrane can be observed safely, but often this requires dry ear precautions. This can be difficult for some children, which may necessitate repair. The presence of significant conductive hearing loss, in selected patients, may necessitate surgical intervention at a younger age. Pathology of the tympanic membrane and ossicular chain often occurs in conjunction with ongoing eustachian tube dysfunction. Eustachian tube function of the opposite ear, in a majority of patients, can help the surgeon assess the risk to the operative ear of recurrence of otitis media or development of middle ear atelectasis.1 Address reprint requests and correspondence: Amy C. Brenski, MD, Department of Otolaryngology Head and Neck Surgery, Division of Pediatric Otolaryngology, Division of Neuro-Otology, University of Texas-Southwestern, 2350 Stemmons Fwy, 5th Floor, Dallas, TX 75235. E-mail address: [email protected]. 1043-1810/$ -see front matter Published by Elsevier Inc. doi:10.1016/j.otot.2009.10.005
As awareness increases about the effects of unilateral and even bilateral mild hearing loss on speech, language and learning parents are more likely to request earlier surgical intervention in children with tympanic membrane perforations and/or ossicular discontinuity.2 Successful tympanoplasty has been described in children as young as 2 years old.3 This creates an operative challenge in younger children and necessitates close postoperative monitoring of the tympanic membrane. Alternate strategies are often required to prevent recurrence of middle ear atelectasis, cholesteatoma, perforation of the tympanic membrane, or further erosion of the ossicular chain. A conservative surgical approach would be to establish a stable, aerated middle ear with an intact tympanic membrane before any attempt at ossicular reconstruction. This usually means staging the procedures. However, in some individual cases, hearing loss is already a significant disability for the child. In the interest of improving the child’s quality of life, ossicular chain reconstruction (OCR) may be indicated. In this instance, it may be considered potentially at the first procedure for extensive cholesteatoma. This can be safe, particularly if a second-look procedure is planned and the family is reliable. Any residual or recurrent cholesteatoma can be addressed safely at that time, but may result in need for revision OCR. Delaying ossicular reconstruction 6 months or more until a second-look may cause undue disability for some children, and primary reconstruc-
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tion may be considered. Nonetheless, caution should be exercised if cholesteatoma extensively involves the ossicular chain or the oval window at the initial procedure.4
Indications OCR can be safely undertaken at any initial otologic procedure in a child where there is a reasonable expectation that the tympanic membrane will heal. However, careful consideration must be given to surgical planning. Multiple authors have shown that there is not much correlation between the size of the perforation and the chance of successful healing of the tympanic membrane reconstruction.5 In the presence of mild hearing loss, or the absence of significant speech delay, it would be reasonable to repair the tympanic membrane first, ensuring a well-aerated middle
Figure 1 The transfacial recess approach allows for reconstruction of the ossicular chain without elevation of the tympanic membrane. A cartilage graft is placed under the posterior–superior quadrant of the tympanic membrane at the initial operation. (A) The shoe of the partial ossicular replacement prosthesis is placed on the stapes superstructure through the facial recess. (B) The head of the prosthesis is then rotated superior and laterally underneath the cartilage graft. No middle ear or ear canal packing is required as the prosthesis secure between the cartilage graft and the stapes. (Reprinted with permission.4)
Figure 2 Titanium middle ear implants with open head piece to allow for better visualization of the stapes capitulum/footplate and the shoe of the prosthesis.
ear and healthy tympanic membrane for transmission of sound. This may be all that is necessary to restore hearing. Moreover, unless there is an obvious gap in the ossicular chain, such as an absent incus or erosion of the stapes superstructure, it is difficult to determine how much of the hearing loss is due to the defect in the tympanic membrane and to the ossicular chain. The goals of surgery must be carefully outlined for the patient and the child’s family. The first goal of otologic surgery is always a safe ear, which includes an intact tympanic membrane. This is also required for the secondary goal, a well aerated middle ear space without negative pressure for normal tympanic membrane mobility. The final goal is to restore hearing. Success with the third goal cannot usually be achieved without the first two.6 The middle ear space and intact tympanic membrane must also be maintained and may require additional surgical intervention before an attempt at ossicular reconstruction, such as a tube placement. The choice of surgical technique is ultimately dictated by the status of the ossicular chain. The minimum requirement for ossiculoplasty is an intact, mobile stapes footplate. For a missing incus, the malleus head can be used for an interposition graft if autologous material is desired. Otherwise, either a partial ossicular replacement or total ossicular re-
Figure 3
Ossicle holding forceps.
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placement prosthesis (TORP) is indicated by the status of the stapes. Many options exist, but some may be better suited based on the presence or position of the malleus. The devices that are designed to be placed medial to the malleus can present additional challenges in the pediatric patient population. The malleus may be medially displaced, destabilized, or destroyed by disease or previous surgery. OCR can be successfully performed even when the malleus is completely absent; however different techniques may be required to stabilize the prosthesis.7 The choice of which surgical technique to use has as much to do with the state of the ossicular chain as the patient in which it occurs. A younger child with probable ongoing eustachian tube dysfunction, for example, may have a better result with an autologous graft vs prosthetic material.
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Approach There are 3 surgical approaches to reconstructing the ossicular chain: (1) transcanal, (2) postauricular transcanal, and (3) postauricular transfacial recess. A transcanal approach is often used in the setting of ossicular discontinuity that is not secondary to cholesteatoma (ie, trauma, congenital malformations and discontinuity, and tympanosclerosis). The size and shape of the external auditory canal in the pediatric population can sometimes limit the surgeon’s ability to reconstruct the ossicular chain through a transcanal approach. Children with syndromes affecting the facial skeleton (ie, Down syndrome, Treacher–Collins syndrome, hemifacial microsomia, CHARGE syndrome, etc.) often have narrow or misshapen canals that make surgical exposure of the ossicular chain more
Figure 4 Sculpting an incus interposition graft. (A) Neoincus outline with well for stapes created at the base of the short process and malleus groove at the joint facet. (B) Product. (C) Lateral view of neoincus in position. (D) Inferior view, showing the posterior and lateral location of the manubrium. (Reprinted with permission.14)
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difficult through a transcanal approach. The conductive hearing loss in these patients may be secondary to partial atresia/ stenosis of the external auditory canal and may require canaloplasty before considering OCR. In some cases, OCR is performed during a second stage mastoid-tympanoplasty. In patients with a history of cholesteatoma involving the mastoid, a postauricular approach is often necessary to look for recurrent or residual disease in the mastoid and epitympanum. Blevins8 described the postauricular transfacial recess approach when staging OCR. The transfacial recess approach necessitates placement of a cartilage graft in the posterior–superior quadrant of the tympanic membrane and performing a wide facial recess with removal of the incus at the initial surgery. This approach allows for immediate improvement in hearing with avoidance of middle ear and ear canal
packing, and obviates the need for ear canal incisions and dry ear precautions (Figure 1).
Material Numerous materials have been used to reconstruct the ossicular chain (ie, plastipore, hydroxyapatite, gold, homograft, autologous bone or ossicles, cartilage, titanium, etc.). The ideal characteristics for a middle ear implant include biocompatibility, suitable rigidity, durability, and easy to manipulate and place.9 The use of cadaveric ossicles (ie, homograft) has largely been abandoned due to concerns of infectious disease transmission. Titanium and hydroxyapatite have most of the ideal characteristics and have become the preferred implants for middle ear reconstruction. The head of the newest gener-
Figure 5 Sculpting an incus transposition graft. (A) Neoincus outline with well for stapes adjacent to the joint facet and the malleus groove where the short process joins the body. (B) Sculpted neoincus. (C) Lateral view of neoincus in place. (D) Inferior view showing malleus in the anterior and medial position. (Reprinted with permission.14)
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ation of ossicular implants provide the surgeon with improved visibility of the stapes that allows for more ideal placement (Figure 2). Extrusion is always a risk when nonautologous materials are used to reconstruct the ossicular chain. Previous studies have shown extrusion rates for hydroxyapatite and titanium to be 4%-21% and 0%-4.4%, respectively. The recent adoption of titanium middle ear implants and placement of a cartilage interposition graft between the implant and tympanic membrane are largely responsible for the discrepancy in extrusion rates between titanium and other materials.10 Positioning a cartilage graft between the implant and tympanic membrane significantly reduces the chance of implant extrusion or exposure.11 Other factors that have been shown to significantly increase the risk of extrusion or exposure
191 include persistent or recurrent middle ear disease, and more importantly eustachian tube dysfunction.12
Autologous grafts and incus interposition The most common form of ossicular discontinuity is erosion of the lenticular process of the incus. This is an ideal situation for use of an incus interposition graft. Even for cholesteatoma, the incus can be used primarily if it is not directly involved with the cholesteatoma. The presence of a malleus is helpful in positioning the incus securely, but successful ossicular reconstruction can be achieved without it.13 The position of the malleus helps determine how to sculpt the incus to bridge the gap between it and the capitulum of the stapes.14 Accurate
Figure 6 Incudostapedial joint cartilage block reconstruction. (A) Defect. (B) Top and side view. (C) Graft in place. (Reprinted with permission.14)
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Figure 7 Applebaum Incudostapedial Joint Prosthesis. Arrowhead: incus long process. Arrow: stapes capitulum. (Reprinted with permission.22)
placement requires obtaining a measurement between the stapes capitulum or footplate and manubrium of the malleus. A 1 and 0.7 mm diamond burr is typically to sculpt the incus. When using a powerful pneumatic drill, it is crucial to secure the incus for drilling. An incus-holder with a stabilizing screw is effective (Figure 3). Other options for ossicle sculpting include using a low-speed electric drill (eg, Skeeter drill). An incus interposition involves reducing the long process of the incus and drilling a well at the short process to accommodate the capitulum. A groove is created on the body of the incus at the nascent incudomalleolar joint to fit adjacent and medial to the manubrium of the malleus when there is minimal malleus offset (Figure 4). An incus transposition is used if the malleus offset is more unfavorable, ie, more medially and anteriorly located. The malleus groove can be created on the side of the body of the incus adjacent to the short process. The stapes well is placed 180° from the malleus groove on the body of the incus adjacent to the incudomalleolar joint (Figure 5).14
Figure 8 Several options are available to reconstruct defects in the incudostapedial joint. (A) Kurz incus bridge prosthesis placed on the residual incus long process and the stapes capitulum. This implant is typically used with bone cement. (B) Kurz Winkel–Clip prosthesis is used for shorter defects in the incus long process. The shoe of the prosthesis clips onto the stapes capitulum whereas the rings can be crimped to the incus long process. (C) The shoe of the Grace Medical Helix Bell is placed on the stapes capitulum whereas the incus long process is placed through the funnel of the prosthesis without bone cement. (D) Bone cement is then applied over the funnel portion of the Grace Medical Helix Bell to secure it to the incus long process.
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For an absent stapes superstructure, the entire incus may be used without any sculpting and simply inverting it, placing the long process of the incus squarely on the footplate. Depending on the length needed, a more stable base may be created by securing the end. The incus may also be secured with bone cement. Another option to secure the incus to the stapes footplate includes sculpting a footplate shoe from cartilage or using a prosthesis. Other options for autologous ossicular reconstruction include the head of the malleus, when the incus has been destroyed or is no longer available. It can be removed from an intact malleus with a malleus nipper by cutting the neck immediately superior to the lateral process. Conchal and tragal cartilage can be used to sculpt a shim for the incudostapedial (IS) joint or a cap for the stapes superstructure.15 Cartilage from the helix has a more blocklike shape than the curved concha or tragus and can be used to create an IS replacement (Figure 6). Any of
193 these autologous ossicular replacements can be secured using bone cement.
Incudostapedial joint replacement There are numerous options for reconstruction of defects in the IS joint using biocompatible materials. Small defects in the incus long or lenticular process are readily repaired with the Applebaum IS joint implant, which is a cube-shaped hydroxyapatite prosthesis (Figure 7). This implant has a groove for the incus long process (arrowhead) and a well for the stapes capitulum (arrow). Reconstruction of the IS with bone cement has the potential to restore near natural anatomic continuity of the ossicular chain.7 Longer defects of the incus long process can be reconstructed with a titanium implants with or without bone cement (Figure 8). Tympanic membrane retraction or a narrow middle ear space may
Figure 9 Selecting the correct size for a prosthesis is a critical step when selecting a middle ear implant. Pre-fashioned sizers can be used to select the appropriate size implant. (A) The Kurz sizer. (B) The Grace Medical sizer. (C) The grace medical adjustable implant system allows the surgeon to adjust and cut the prosthesis to the desired length.
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result in implant extrusion or exposure that can be prevented with placement of a cartilage graft.
Partial ossicular replacement prosthesis and total ossicular replacement prosthesis The use of a partial ossicular replacement prosthesis (PORP) or TORP is indicated in the setting of ossicular discontinuity or lateral chain fixation. There are numerous adjustable and fixed length hydroxyapatite, titanium, and composite PORPs and TORPs available to reconstruct the ossicular chain. The presence of an intact stapes superstructure and ideally a capitulum is necessary for the placement of a PORP; whereas a TORP can be placed with or without
a stapes superstructure. Studies have demonstrated that the presence and use of the malleus handle in middle ear reconstruction has been shown to improve the hearing results.16 The malleus is often offset from the stapes that makes use of the malleus handle more challenging.17 Vincent et al have described a technique to reposition the malleus when there is a significant offset.17 Several implants are available that have a curved arm or groove that is placed medial to the malleus handle. Various implant sizers or a measuring rod can be used to measure the distance between the stapes capitulum or footplate and malleus handle (Figure 9). Closure of the air-bone gap and stability of postoperative hearing is often more difficult with a TORP as the implant cannot be secured to the stapes superstructure. Several op-
Figure 10 Various footplate shoes have been developed to better secure a total ossicular replacement prosthesis on to the stapes. (A) Grace Medical footplate shoe. (B) Kurz Omega footplate shoe. (C) Kurz cartilage punch is used to make a footplate shoe from autologous cartilage. (D) A total ossicular replacement prosthesisis placed through a cartilage shoe to stabilize it in the oval window.
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195 repositioned, and the ear canal is filled with packing. The postauricular incision is closed in layers taking care to reapproximate the periosteum and skin.
Complications The most common problem complicating ossiculoplasty in children is residual eustachian tube dysfunction. Early complications include acute otitis media and perforation. Preoperative adenoidectomy may improve eustachian tube dysfunction and prevent this common problem.19 Other surgical strategies to consider include cartilage tympanoplasty20 or adding a mastoidectomy.19 Negative pressure can lead to atelectasis, displacement of the prosthesis with hearing deterioration, and ultimately extrusion of the prosthesis.21 More serious complications can occur resulting from cholesteatoma formation or erosion of the footplate by a prosthesis with both vestibular and auditory symptoms. Imaging may help determine the cause of failure, show previous attempts at ossicular reconstruction by another surgeon, and possibly anticipate some of the more serious complications.22
Figure 11 It is often desirable to thin the cartilage before placing it between the implant and the tympanic membrane. A Kurz cartilage knife allows the surgeon to thin a cartilage graft.
tions are now available to prevent displacement of a TORP off the stapes footplate (Figure 10). Beutner et al18 demonstrated positional stability of a TORP when a cartilage shoe was used in the setting of an absent stapes superstructure. The surgeon must account for the thickness of the cartilage interposition graft when selecting or designing an appropriately sized implant. A cartilage graft with or without perichondrium can be harvested from the concha or tragus. The cartilage can then be thinned manually or with a specialized cartilage knife (Figure 11). The cartilage graft is then trimmed, so it is larger than the size of the implant head. Before placing a middle ear implant, the stapes superstructure and footplate are exposed and palpated to assess for mobility. The middle ear is then filled with packing except for around the stapes superstructure and footplate. The shoe of the prosthesis is placed on the stapes superstructure or footplate. Care must be taken not to position the implant too anteriorly as this may increase the risk of the prosthesis becoming displaced. The cartilage graft is then placed on the head of the prosthesis that is then tilted towards the center of the tympanic membrane or medial to the malleus handle. The tympanomeatal flap is then repositioned over the posterior external auditory canal. The position of the prosthesis can then be assessed through the facial recess if the surgeon has used the postauricular approach. Prosthesis movement can also be assessed by gently palpating the tympanic membrane while looking at the stapes footplate through the facial recess. The vascular strip is carefully
Contraindications A possible contraindication to OCR would be an extensive cholesteatoma involving the oval window with questionable integrity of the stapes footplate. Cholesteatoma involvement of the incus and stapes is a relative contraindication for reconstruction at the initial surgery, and the patient may benefit from delaying the reconstruction until the secondlook procedure.4 If the incus is involved with cholesteatoma, some authors recommended careful debridement of the incus and then placing it into the mastoid cavity, or “banking” it. It can then be carefully examined at the second look procedure and used for ossicular reconstruction if is free of disease.23 Another relative contraindication would be a concurrent perforation with some connectivity remaining between the ossicles. It can be difficult to predict how much of the conductive hearing loss is because of the perforation of the tympanic membrane and middle ear scar tissue and how much is due to the partially eroded ossicles. Even if a round window light reflex is present on middle ear exploration and palpation of the ossicles, it may not be a good predictor of hearing outcome. In the latter instance, it may be prudent to delay ossicular reconstruction until the tympanic membrane has healed and audiologic testing has confirmed the persistence and severity of hearing loss. For hearing loss with a significant sensorineural component, conservative intervention is usually appropriate. Once the tympanic membrane has healed and an aerated middle ear space achieved, continued conductive hearing loss can be addressed with ossicular reconstruction. Congenital inner ear anomalies can be associated with mixed hearing loss, therefore the surgeon should consider the use of computed
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tomography or magnetic resonance imaging in the presurgical evaluation in any patient with a significant component of sensorineural hearing loss. If an anomaly such as large vestibular aqueduct is present, the hearing may be unstable, and it is impossible to predict how much of the conductive hearing loss is related to the inner ear anomaly.24 A hearing aid may be a better option for theses patients. In general, OCR should be avoided in patients with inner ear anomalies.24 Amplification should always be offered to the patient and family in any situation as an alternative to surgical intervention whenever it is a viable option.
References 1. Murphy TP: Hearing results in pediatric patients with chronic otitis media after partial ossicular replacement prosthesis and total ossicular replacement prosthesis. Laryngoscope 110:536-544, 2000 2. Tharpe AM: Unilateral and mild bilateral hearing loss in children: Past and current perspectives. Trends Amplif 12:7-15, 2008 3. Koch WM, Friedman EM, McGill TJ, et al: Tympanoplasty in children: The Boston Children’s Hospital experience. Arch Otolaryngol Head Neck Surg 116:35-40, 1990 4. Kim HH, Battista RA, Kumar A, et al: Should ossicular reconstruction be staged following tympanomastoidectomy? Laryngoscope 116:4751, 2006 5. Chandresekhar SS, House JW, Devgan U: Pediatric tympanoplasty: A ten year experience. Otolaryngol Head Neck Surg 121:873-878, 1995 6. Collins WO, Telischi FF, Balkany TJ, et al: Pediatric tympanoplasty, effect of contralateral ear status on outcomes. Arch Otolaryngol Head Neck Surg 129:646-651, 2003 7. Dornhoffer JL, Gardner E: Prognostic factors in ossiculoplasty: A statistical staging system. Otol Neurotol 22:299-304, 2001 8. Blevins NH: Transfacial recess ossicular reconstruction: Technique and early results. Otol Neurotol 25:236-241, 2004 9. Gardner EK, Jackson CG, Kaylie DM: Results with titanium ossicular reconstruction prostheses. Laryngoscope 114:65-70, 2004
10. Truy E, Naiman AN, Pavillon C, et al: Hydroxyapatite versus titanium ossiculoplasty. Otol Neurotol 28:492-498, 2007 11. Kobayashi T, Gyo K, Shinohara T, et al: Ossicular reconstruction using hydroxyapatite prostheses with interposed cartilage. Am J Otolaryngol 23:222-227, 2002 12. Vrabec JT, Stierman K, Grady JJ: Hydroxyapatite prosthesis extrusion. Otol Neurotol 23:653-656, 2002 13. Martin C, Timeshenko AC, Martin C, et al: Malleus removal and total cartilage reinforcement in intact canal wall tympanoplasty for cholesteatoma. Ann Otol Rhinol Laryngol 113:421-425, 2004 14. Pyle MG: Ossicular sculpting for conductive hearing loss. Op Tech Otolaryngol 14:237-242, 2003 15. Goebel JA, Jacob A: Use of Mimix hydroxyapatite bone cement for difficult ossicular reconstruction. Otolaryngol Head Neck Surg 132: 727-734, 2005 16. Todd NW: The malleus-stapes offset. Laryngoscope 118:110-115, 2008 17. Vincent R, Oates J, Sperling NM, et al: Malleus relocation in ossicular reconstruction: Managing the anteriorly positioned malleus: Results in a series of 268 cases. Otol Neurotol 25:223-230, 2004 18. Beutner D, Luers JC, Huttenbrink KB: Cartilage ‘shoe’: A new technique for stabilization of titanium total ossicular replacement prosthesis at center of stapes footplate. J Laryngol Otol 122:682-686, 2008 19. McGrew BM, Jackson CG, Glasscock ME 3rd: Impact of mastoidectomy on simple tympanic membrane perforation repair. Laryngoscope 114:506-511, 2004 20. Dornhoffer JL: Cartilage tympanoplasty. Otolaryngol Clin North Am 30:1161-1176, 2006 21. Mishiro Y, Sakagami M, Kitahara T, et al: Long-term hearing outcomes after ossiculoplasty in comparison to short-term outcomes. Otol Neurotol 29:326-329, 2008 22. Stone JA, Mukherji SK, Jewett BS, et al: CT evaluation of prosthetic ossicular reconstruction procedures: What the otologist needs to know. Radiographics 20:593-605, 2000 23. Gyo K, Hato N, Shinomori Y, et al: Storage of the incus in the mastoid bowl for use as a columella in staged tympanoplasty. Auris Nasus Larynx 34:5-8, 2004 24. Zhou G, Gopen Q, Kenna MA: Delineating the hearing loss in children with enlarged vestibular aqueduct. Laryngoscope 118:2062-2066, 2008
Reconstruction of the ossicular chain in children Amy C. Brenski, MD, Brandson Isaacson, MD From the Department of Otolaryngology Head and Neck Surgery, Division of Pediatric Otolaryngology, Division of Neuro-Otology, University of Texas-Southwestern, Dallas, Texas. KEYWORDS Ossicular chain; Ossiculoplasty; Incus interposition; Prothesis; Incus transposition
Ossiculoplasty in pediatric patients presents several unique surgical challenges. A conservative approach includes establishing a safe, well-aerated middle ear with an intact tympanic membrane before attempting reconstruction of the ossicular chain. However, a more aggressive approach with immediate ossicular reconstruction may be indicated in certain clinical situations. Close monitoring during postoperative healing is important to achieve and maintain a good hearing result. However, successful ossicular reconstruction can be achieved in children. It may have a more important role in children given the importance of binaural hearing in speech and language development and success in education. In this article, the authors describe their operative approach to reconstruction of the ossicular chain in children. Published by Elsevier Inc.
The result of chronic otitis media and cholesteatoma in children is often conductive hearing loss due to tympanic membrane perforation and/or erosion of the ossicular chain. More commonly, chronic suppurative otitis media through a chronic tympanic membrane perforation results in erosion of the ossicular chain over time and subsequently hearing loss. A less frequent cause of conductive hearing loss is trauma to the temporal bone or middle ear causing disruption of the ossicular chain. Ossiculoplasty is a reasonable option for the restoration of hearing in children. However, there are special considerations in the pediatric population. A stable, central, dry tympanic membrane can be observed safely, but often this requires dry ear precautions. This can be difficult for some children, which may necessitate repair. The presence of significant conductive hearing loss, in selected patients, may necessitate surgical intervention at a younger age. Pathology of the tympanic membrane and ossicular chain often occurs in conjunction with ongoing eustachian tube dysfunction. Eustachian tube function of the opposite ear, in a majority of patients, can help the surgeon assess the risk to the operative ear of recurrence of otitis media or development of middle ear atelectasis.1 Address reprint requests and correspondence: Amy C. Brenski, MD, Department of Otolaryngology Head and Neck Surgery, Division of Pediatric Otolaryngology, Division of Neuro-Otology, University of Texas-Southwestern, 2350 Stemmons Fwy, 5th Floor, Dallas, TX 75235. E-mail address: [email protected]. 1043-1810/$ -see front matter Published by Elsevier Inc. doi:10.1016/j.otot.2009.10.005
As awareness increases about the effects of unilateral and even bilateral mild hearing loss on speech, language and learning parents are more likely to request earlier surgical intervention in children with tympanic membrane perforations and/or ossicular discontinuity.2 Successful tympanoplasty has been described in children as young as 2 years old.3 This creates an operative challenge in younger children and necessitates close postoperative monitoring of the tympanic membrane. Alternate strategies are often required to prevent recurrence of middle ear atelectasis, cholesteatoma, perforation of the tympanic membrane, or further erosion of the ossicular chain. A conservative surgical approach would be to establish a stable, aerated middle ear with an intact tympanic membrane before any attempt at ossicular reconstruction. This usually means staging the procedures. However, in some individual cases, hearing loss is already a significant disability for the child. In the interest of improving the child’s quality of life, ossicular chain reconstruction (OCR) may be indicated. In this instance, it may be considered potentially at the first procedure for extensive cholesteatoma. This can be safe, particularly if a second-look procedure is planned and the family is reliable. Any residual or recurrent cholesteatoma can be addressed safely at that time, but may result in need for revision OCR. Delaying ossicular reconstruction 6 months or more until a second-look may cause undue disability for some children, and primary reconstruc-
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tion may be considered. Nonetheless, caution should be exercised if cholesteatoma extensively involves the ossicular chain or the oval window at the initial procedure.4
Indications OCR can be safely undertaken at any initial otologic procedure in a child where there is a reasonable expectation that the tympanic membrane will heal. However, careful consideration must be given to surgical planning. Multiple authors have shown that there is not much correlation between the size of the perforation and the chance of successful healing of the tympanic membrane reconstruction.5 In the presence of mild hearing loss, or the absence of significant speech delay, it would be reasonable to repair the tympanic membrane first, ensuring a well-aerated middle
Figure 1 The transfacial recess approach allows for reconstruction of the ossicular chain without elevation of the tympanic membrane. A cartilage graft is placed under the posterior–superior quadrant of the tympanic membrane at the initial operation. (A) The shoe of the partial ossicular replacement prosthesis is placed on the stapes superstructure through the facial recess. (B) The head of the prosthesis is then rotated superior and laterally underneath the cartilage graft. No middle ear or ear canal packing is required as the prosthesis secure between the cartilage graft and the stapes. (Reprinted with permission.4)
Figure 2 Titanium middle ear implants with open head piece to allow for better visualization of the stapes capitulum/footplate and the shoe of the prosthesis.
ear and healthy tympanic membrane for transmission of sound. This may be all that is necessary to restore hearing. Moreover, unless there is an obvious gap in the ossicular chain, such as an absent incus or erosion of the stapes superstructure, it is difficult to determine how much of the hearing loss is due to the defect in the tympanic membrane and to the ossicular chain. The goals of surgery must be carefully outlined for the patient and the child’s family. The first goal of otologic surgery is always a safe ear, which includes an intact tympanic membrane. This is also required for the secondary goal, a well aerated middle ear space without negative pressure for normal tympanic membrane mobility. The final goal is to restore hearing. Success with the third goal cannot usually be achieved without the first two.6 The middle ear space and intact tympanic membrane must also be maintained and may require additional surgical intervention before an attempt at ossicular reconstruction, such as a tube placement. The choice of surgical technique is ultimately dictated by the status of the ossicular chain. The minimum requirement for ossiculoplasty is an intact, mobile stapes footplate. For a missing incus, the malleus head can be used for an interposition graft if autologous material is desired. Otherwise, either a partial ossicular replacement or total ossicular re-
Figure 3
Ossicle holding forceps.
Brenski and Isaacson
Operative Techniques in Otolaryngology
placement prosthesis (TORP) is indicated by the status of the stapes. Many options exist, but some may be better suited based on the presence or position of the malleus. The devices that are designed to be placed medial to the malleus can present additional challenges in the pediatric patient population. The malleus may be medially displaced, destabilized, or destroyed by disease or previous surgery. OCR can be successfully performed even when the malleus is completely absent; however different techniques may be required to stabilize the prosthesis.7 The choice of which surgical technique to use has as much to do with the state of the ossicular chain as the patient in which it occurs. A younger child with probable ongoing eustachian tube dysfunction, for example, may have a better result with an autologous graft vs prosthetic material.
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Approach There are 3 surgical approaches to reconstructing the ossicular chain: (1) transcanal, (2) postauricular transcanal, and (3) postauricular transfacial recess. A transcanal approach is often used in the setting of ossicular discontinuity that is not secondary to cholesteatoma (ie, trauma, congenital malformations and discontinuity, and tympanosclerosis). The size and shape of the external auditory canal in the pediatric population can sometimes limit the surgeon’s ability to reconstruct the ossicular chain through a transcanal approach. Children with syndromes affecting the facial skeleton (ie, Down syndrome, Treacher–Collins syndrome, hemifacial microsomia, CHARGE syndrome, etc.) often have narrow or misshapen canals that make surgical exposure of the ossicular chain more
Figure 4 Sculpting an incus interposition graft. (A) Neoincus outline with well for stapes created at the base of the short process and malleus groove at the joint facet. (B) Product. (C) Lateral view of neoincus in position. (D) Inferior view, showing the posterior and lateral location of the manubrium. (Reprinted with permission.14)
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difficult through a transcanal approach. The conductive hearing loss in these patients may be secondary to partial atresia/ stenosis of the external auditory canal and may require canaloplasty before considering OCR. In some cases, OCR is performed during a second stage mastoid-tympanoplasty. In patients with a history of cholesteatoma involving the mastoid, a postauricular approach is often necessary to look for recurrent or residual disease in the mastoid and epitympanum. Blevins8 described the postauricular transfacial recess approach when staging OCR. The transfacial recess approach necessitates placement of a cartilage graft in the posterior–superior quadrant of the tympanic membrane and performing a wide facial recess with removal of the incus at the initial surgery. This approach allows for immediate improvement in hearing with avoidance of middle ear and ear canal
packing, and obviates the need for ear canal incisions and dry ear precautions (Figure 1).
Material Numerous materials have been used to reconstruct the ossicular chain (ie, plastipore, hydroxyapatite, gold, homograft, autologous bone or ossicles, cartilage, titanium, etc.). The ideal characteristics for a middle ear implant include biocompatibility, suitable rigidity, durability, and easy to manipulate and place.9 The use of cadaveric ossicles (ie, homograft) has largely been abandoned due to concerns of infectious disease transmission. Titanium and hydroxyapatite have most of the ideal characteristics and have become the preferred implants for middle ear reconstruction. The head of the newest gener-
Figure 5 Sculpting an incus transposition graft. (A) Neoincus outline with well for stapes adjacent to the joint facet and the malleus groove where the short process joins the body. (B) Sculpted neoincus. (C) Lateral view of neoincus in place. (D) Inferior view showing malleus in the anterior and medial position. (Reprinted with permission.14)
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ation of ossicular implants provide the surgeon with improved visibility of the stapes that allows for more ideal placement (Figure 2). Extrusion is always a risk when nonautologous materials are used to reconstruct the ossicular chain. Previous studies have shown extrusion rates for hydroxyapatite and titanium to be 4%-21% and 0%-4.4%, respectively. The recent adoption of titanium middle ear implants and placement of a cartilage interposition graft between the implant and tympanic membrane are largely responsible for the discrepancy in extrusion rates between titanium and other materials.10 Positioning a cartilage graft between the implant and tympanic membrane significantly reduces the chance of implant extrusion or exposure.11 Other factors that have been shown to significantly increase the risk of extrusion or exposure
191 include persistent or recurrent middle ear disease, and more importantly eustachian tube dysfunction.12
Autologous grafts and incus interposition The most common form of ossicular discontinuity is erosion of the lenticular process of the incus. This is an ideal situation for use of an incus interposition graft. Even for cholesteatoma, the incus can be used primarily if it is not directly involved with the cholesteatoma. The presence of a malleus is helpful in positioning the incus securely, but successful ossicular reconstruction can be achieved without it.13 The position of the malleus helps determine how to sculpt the incus to bridge the gap between it and the capitulum of the stapes.14 Accurate
Figure 6 Incudostapedial joint cartilage block reconstruction. (A) Defect. (B) Top and side view. (C) Graft in place. (Reprinted with permission.14)
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Figure 7 Applebaum Incudostapedial Joint Prosthesis. Arrowhead: incus long process. Arrow: stapes capitulum. (Reprinted with permission.22)
placement requires obtaining a measurement between the stapes capitulum or footplate and manubrium of the malleus. A 1 and 0.7 mm diamond burr is typically to sculpt the incus. When using a powerful pneumatic drill, it is crucial to secure the incus for drilling. An incus-holder with a stabilizing screw is effective (Figure 3). Other options for ossicle sculpting include using a low-speed electric drill (eg, Skeeter drill). An incus interposition involves reducing the long process of the incus and drilling a well at the short process to accommodate the capitulum. A groove is created on the body of the incus at the nascent incudomalleolar joint to fit adjacent and medial to the manubrium of the malleus when there is minimal malleus offset (Figure 4). An incus transposition is used if the malleus offset is more unfavorable, ie, more medially and anteriorly located. The malleus groove can be created on the side of the body of the incus adjacent to the short process. The stapes well is placed 180° from the malleus groove on the body of the incus adjacent to the incudomalleolar joint (Figure 5).14
Figure 8 Several options are available to reconstruct defects in the incudostapedial joint. (A) Kurz incus bridge prosthesis placed on the residual incus long process and the stapes capitulum. This implant is typically used with bone cement. (B) Kurz Winkel–Clip prosthesis is used for shorter defects in the incus long process. The shoe of the prosthesis clips onto the stapes capitulum whereas the rings can be crimped to the incus long process. (C) The shoe of the Grace Medical Helix Bell is placed on the stapes capitulum whereas the incus long process is placed through the funnel of the prosthesis without bone cement. (D) Bone cement is then applied over the funnel portion of the Grace Medical Helix Bell to secure it to the incus long process.
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For an absent stapes superstructure, the entire incus may be used without any sculpting and simply inverting it, placing the long process of the incus squarely on the footplate. Depending on the length needed, a more stable base may be created by securing the end. The incus may also be secured with bone cement. Another option to secure the incus to the stapes footplate includes sculpting a footplate shoe from cartilage or using a prosthesis. Other options for autologous ossicular reconstruction include the head of the malleus, when the incus has been destroyed or is no longer available. It can be removed from an intact malleus with a malleus nipper by cutting the neck immediately superior to the lateral process. Conchal and tragal cartilage can be used to sculpt a shim for the incudostapedial (IS) joint or a cap for the stapes superstructure.15 Cartilage from the helix has a more blocklike shape than the curved concha or tragus and can be used to create an IS replacement (Figure 6). Any of
193 these autologous ossicular replacements can be secured using bone cement.
Incudostapedial joint replacement There are numerous options for reconstruction of defects in the IS joint using biocompatible materials. Small defects in the incus long or lenticular process are readily repaired with the Applebaum IS joint implant, which is a cube-shaped hydroxyapatite prosthesis (Figure 7). This implant has a groove for the incus long process (arrowhead) and a well for the stapes capitulum (arrow). Reconstruction of the IS with bone cement has the potential to restore near natural anatomic continuity of the ossicular chain.7 Longer defects of the incus long process can be reconstructed with a titanium implants with or without bone cement (Figure 8). Tympanic membrane retraction or a narrow middle ear space may
Figure 9 Selecting the correct size for a prosthesis is a critical step when selecting a middle ear implant. Pre-fashioned sizers can be used to select the appropriate size implant. (A) The Kurz sizer. (B) The Grace Medical sizer. (C) The grace medical adjustable implant system allows the surgeon to adjust and cut the prosthesis to the desired length.
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result in implant extrusion or exposure that can be prevented with placement of a cartilage graft.
Partial ossicular replacement prosthesis and total ossicular replacement prosthesis The use of a partial ossicular replacement prosthesis (PORP) or TORP is indicated in the setting of ossicular discontinuity or lateral chain fixation. There are numerous adjustable and fixed length hydroxyapatite, titanium, and composite PORPs and TORPs available to reconstruct the ossicular chain. The presence of an intact stapes superstructure and ideally a capitulum is necessary for the placement of a PORP; whereas a TORP can be placed with or without
a stapes superstructure. Studies have demonstrated that the presence and use of the malleus handle in middle ear reconstruction has been shown to improve the hearing results.16 The malleus is often offset from the stapes that makes use of the malleus handle more challenging.17 Vincent et al have described a technique to reposition the malleus when there is a significant offset.17 Several implants are available that have a curved arm or groove that is placed medial to the malleus handle. Various implant sizers or a measuring rod can be used to measure the distance between the stapes capitulum or footplate and malleus handle (Figure 9). Closure of the air-bone gap and stability of postoperative hearing is often more difficult with a TORP as the implant cannot be secured to the stapes superstructure. Several op-
Figure 10 Various footplate shoes have been developed to better secure a total ossicular replacement prosthesis on to the stapes. (A) Grace Medical footplate shoe. (B) Kurz Omega footplate shoe. (C) Kurz cartilage punch is used to make a footplate shoe from autologous cartilage. (D) A total ossicular replacement prosthesisis placed through a cartilage shoe to stabilize it in the oval window.
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195 repositioned, and the ear canal is filled with packing. The postauricular incision is closed in layers taking care to reapproximate the periosteum and skin.
Complications The most common problem complicating ossiculoplasty in children is residual eustachian tube dysfunction. Early complications include acute otitis media and perforation. Preoperative adenoidectomy may improve eustachian tube dysfunction and prevent this common problem.19 Other surgical strategies to consider include cartilage tympanoplasty20 or adding a mastoidectomy.19 Negative pressure can lead to atelectasis, displacement of the prosthesis with hearing deterioration, and ultimately extrusion of the prosthesis.21 More serious complications can occur resulting from cholesteatoma formation or erosion of the footplate by a prosthesis with both vestibular and auditory symptoms. Imaging may help determine the cause of failure, show previous attempts at ossicular reconstruction by another surgeon, and possibly anticipate some of the more serious complications.22
Figure 11 It is often desirable to thin the cartilage before placing it between the implant and the tympanic membrane. A Kurz cartilage knife allows the surgeon to thin a cartilage graft.
tions are now available to prevent displacement of a TORP off the stapes footplate (Figure 10). Beutner et al18 demonstrated positional stability of a TORP when a cartilage shoe was used in the setting of an absent stapes superstructure. The surgeon must account for the thickness of the cartilage interposition graft when selecting or designing an appropriately sized implant. A cartilage graft with or without perichondrium can be harvested from the concha or tragus. The cartilage can then be thinned manually or with a specialized cartilage knife (Figure 11). The cartilage graft is then trimmed, so it is larger than the size of the implant head. Before placing a middle ear implant, the stapes superstructure and footplate are exposed and palpated to assess for mobility. The middle ear is then filled with packing except for around the stapes superstructure and footplate. The shoe of the prosthesis is placed on the stapes superstructure or footplate. Care must be taken not to position the implant too anteriorly as this may increase the risk of the prosthesis becoming displaced. The cartilage graft is then placed on the head of the prosthesis that is then tilted towards the center of the tympanic membrane or medial to the malleus handle. The tympanomeatal flap is then repositioned over the posterior external auditory canal. The position of the prosthesis can then be assessed through the facial recess if the surgeon has used the postauricular approach. Prosthesis movement can also be assessed by gently palpating the tympanic membrane while looking at the stapes footplate through the facial recess. The vascular strip is carefully
Contraindications A possible contraindication to OCR would be an extensive cholesteatoma involving the oval window with questionable integrity of the stapes footplate. Cholesteatoma involvement of the incus and stapes is a relative contraindication for reconstruction at the initial surgery, and the patient may benefit from delaying the reconstruction until the secondlook procedure.4 If the incus is involved with cholesteatoma, some authors recommended careful debridement of the incus and then placing it into the mastoid cavity, or “banking” it. It can then be carefully examined at the second look procedure and used for ossicular reconstruction if is free of disease.23 Another relative contraindication would be a concurrent perforation with some connectivity remaining between the ossicles. It can be difficult to predict how much of the conductive hearing loss is because of the perforation of the tympanic membrane and middle ear scar tissue and how much is due to the partially eroded ossicles. Even if a round window light reflex is present on middle ear exploration and palpation of the ossicles, it may not be a good predictor of hearing outcome. In the latter instance, it may be prudent to delay ossicular reconstruction until the tympanic membrane has healed and audiologic testing has confirmed the persistence and severity of hearing loss. For hearing loss with a significant sensorineural component, conservative intervention is usually appropriate. Once the tympanic membrane has healed and an aerated middle ear space achieved, continued conductive hearing loss can be addressed with ossicular reconstruction. Congenital inner ear anomalies can be associated with mixed hearing loss, therefore the surgeon should consider the use of computed
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tomography or magnetic resonance imaging in the presurgical evaluation in any patient with a significant component of sensorineural hearing loss. If an anomaly such as large vestibular aqueduct is present, the hearing may be unstable, and it is impossible to predict how much of the conductive hearing loss is related to the inner ear anomaly.24 A hearing aid may be a better option for theses patients. In general, OCR should be avoided in patients with inner ear anomalies.24 Amplification should always be offered to the patient and family in any situation as an alternative to surgical intervention whenever it is a viable option.
References 1. Murphy TP: Hearing results in pediatric patients with chronic otitis media after partial ossicular replacement prosthesis and total ossicular replacement prosthesis. Laryngoscope 110:536-544, 2000 2. Tharpe AM: Unilateral and mild bilateral hearing loss in children: Past and current perspectives. Trends Amplif 12:7-15, 2008 3. Koch WM, Friedman EM, McGill TJ, et al: Tympanoplasty in children: The Boston Children’s Hospital experience. Arch Otolaryngol Head Neck Surg 116:35-40, 1990 4. Kim HH, Battista RA, Kumar A, et al: Should ossicular reconstruction be staged following tympanomastoidectomy? Laryngoscope 116:4751, 2006 5. Chandresekhar SS, House JW, Devgan U: Pediatric tympanoplasty: A ten year experience. Otolaryngol Head Neck Surg 121:873-878, 1995 6. Collins WO, Telischi FF, Balkany TJ, et al: Pediatric tympanoplasty, effect of contralateral ear status on outcomes. Arch Otolaryngol Head Neck Surg 129:646-651, 2003 7. Dornhoffer JL, Gardner E: Prognostic factors in ossiculoplasty: A statistical staging system. Otol Neurotol 22:299-304, 2001 8. Blevins NH: Transfacial recess ossicular reconstruction: Technique and early results. Otol Neurotol 25:236-241, 2004 9. Gardner EK, Jackson CG, Kaylie DM: Results with titanium ossicular reconstruction prostheses. Laryngoscope 114:65-70, 2004
10. Truy E, Naiman AN, Pavillon C, et al: Hydroxyapatite versus titanium ossiculoplasty. Otol Neurotol 28:492-498, 2007 11. Kobayashi T, Gyo K, Shinohara T, et al: Ossicular reconstruction using hydroxyapatite prostheses with interposed cartilage. Am J Otolaryngol 23:222-227, 2002 12. Vrabec JT, Stierman K, Grady JJ: Hydroxyapatite prosthesis extrusion. Otol Neurotol 23:653-656, 2002 13. Martin C, Timeshenko AC, Martin C, et al: Malleus removal and total cartilage reinforcement in intact canal wall tympanoplasty for cholesteatoma. Ann Otol Rhinol Laryngol 113:421-425, 2004 14. Pyle MG: Ossicular sculpting for conductive hearing loss. Op Tech Otolaryngol 14:237-242, 2003 15. Goebel JA, Jacob A: Use of Mimix hydroxyapatite bone cement for difficult ossicular reconstruction. Otolaryngol Head Neck Surg 132: 727-734, 2005 16. Todd NW: The malleus-stapes offset. Laryngoscope 118:110-115, 2008 17. Vincent R, Oates J, Sperling NM, et al: Malleus relocation in ossicular reconstruction: Managing the anteriorly positioned malleus: Results in a series of 268 cases. Otol Neurotol 25:223-230, 2004 18. Beutner D, Luers JC, Huttenbrink KB: Cartilage ‘shoe’: A new technique for stabilization of titanium total ossicular replacement prosthesis at center of stapes footplate. J Laryngol Otol 122:682-686, 2008 19. McGrew BM, Jackson CG, Glasscock ME 3rd: Impact of mastoidectomy on simple tympanic membrane perforation repair. Laryngoscope 114:506-511, 2004 20. Dornhoffer JL: Cartilage tympanoplasty. Otolaryngol Clin North Am 30:1161-1176, 2006 21. Mishiro Y, Sakagami M, Kitahara T, et al: Long-term hearing outcomes after ossiculoplasty in comparison to short-term outcomes. Otol Neurotol 29:326-329, 2008 22. Stone JA, Mukherji SK, Jewett BS, et al: CT evaluation of prosthetic ossicular reconstruction procedures: What the otologist needs to know. Radiographics 20:593-605, 2000 23. Gyo K, Hato N, Shinomori Y, et al: Storage of the incus in the mastoid bowl for use as a columella in staged tympanoplasty. Auris Nasus Larynx 34:5-8, 2004 24. Zhou G, Gopen Q, Kenna MA: Delineating the hearing loss in children with enlarged vestibular aqueduct. Laryngoscope 118:2062-2066, 2008