Abstract
Diagnosis: Postinflammatory fibrosis of the EAC (medial canal fibrosis) Postinflammatory fibrosis of the EAC is an acquired condition that is characterized by mature fibrotic tissue lateral to the tympanic membrane. It is twice as common in women as men, and 50% of the cases are bilateral.1,2 A 20- to 40-dB conductive hearing loss, low-compliance tympanograms, and intermittent otorrhea are common symptoms at presentation.2 Postinflammatory fibrosis of the EAC is believed to represent the end stage of chronic otitis externa. Other potential risk factors include EAC trauma and prior otologic surgery1; it can also occur as a complication of allergy or dermatitis.3 Tos and Bale4 described 4 basic subdivisions: posttraumatic, postoperative, neoplastic, and postinflammatory. There is thought to be an early (wet) stage and a late (dry) stage in this disease process.5 An active or wet stage occurs early in the course of the disease. Symptomatically, patients report otorrhea and otalgia. Edema of EAC skin can be accompanied by granulation tissue. In the late phase, proliferation of the subepithelial layer results in resolution of active otorrhea and eventual blind closure of the EAC with mature skin. Conductive hearing loss is the most common patient complaint.6 The differential diagnosis includes keratosis obturans and EAC cholesteatoma. Complete opacification, with a subtle erosion of the bony EAC, may be present in cases of keratosis obturans, whereas bony changes are uncommon in cases of EAC fibrosis. Although these 2 entities look similar on computed tomograms, they are usually distinguished on clinical examination. Cholesteatoma of the EAC may present as a focal soft tissue mass with underlying bony erosion. Other conditions to be ruled out include primary EAC malignancy, lupus erythematosus, histiocytosis X, and tertiary syphilis.6 The active phase of external otitis is treated with irrigations to return the EAC to a normal pH (4-5) and to remove debris. Ototopical antibiotics are used in nonresolving cases. Steroid ointments or creams are useful in the chronic phase of external otitis without bacterial involvement. Surgery is the best option for cure once mature fibrosis is established in the EAC. Surgery is contraindicated in cases involving uncontrolled ear canal dermatitis or multiple failed surgical attempts as well as in those in which patients continue to manipulate or irritate their EAC skin. Canalplasty with removal of fibrous tissue and involved skin, meatoplasty, and reconstruction with a skin graft can be performed in a single stage through an endaural or a postauricular approach.6 Complete removal of all fibrous tissue is required to minimize the risk of restenosis.4 The bony EAC should be enlarged enough to allow direct visualization for precise skin graft placement and to avoid trapping squamous debris deep to the new skin lining. Healing in the EAC without restenosis is reported to be as high as 80%.5 Postoperative care should be meticulous. We favor the use of ear sponges (Merocel Pope Oto-Wick; Medtronic Xomed, Jacksonville, Fla) instead of gelfoam because of reduced inflammatory response. Packing is removed at 7 to 10 days, and the patients are seen again 4 weeks after surgery for debridement and local steroid injection (Kenalog, 40 mg/mL) as needed to prevent restenosis. Hearing aids should be avoided for a minimum of 6 weeks after surgery. Reepithelialization of the EAC is crucial to prevent granulation tissue formation and restenosis.7 In 1 study, 2 of 14 cases required reoperation with split-skin grafts.4 Restenosis may occur years after surgical correction, especially in cases in which bone was left exposed or when the patient has a dermatalogic condition.2,4 In an attempt to prevent restenosis, various techniques have been used, including stenting, expandable wicks, rotational cutaneous flaps, and skin or cartilage grafts.8 Postoperative granulation tissue in the EAC and mastoid is treated with corticosteroid injections, surgical debridement, silver nitrate cauterization, and topical antibiotics. Topical mitomycin reduces scar tissue by inhibiting fibroblast proliferation, but a recent prospective, pilot study showed that it is ineffective in the postsurgical EAC.9 Other potential surgical complications include postoperative infection (which may lead to restenosis), iatrogenic tympanic membrane perforation, conductive hearing loss, and EAC cholesteatoma. We suspect that our patient's stenosis was the result of mechanical trauma due to long-term hearing aid use. He had no other dermatitis or chronic infections. He underwent 2 single-stage canalplasties with complete removal of the involved EAC skin, preservation of the middle and inner layers of the tympanic membrane, and regrafting with postauricular skin. The second ear was surgically treated 6 weeks after the first operation to allow ample time for healing in the first ear. In conclusion, postinflammatory stenosis of the EAC can be frustrating to treat and requires meticulous postoperative care to minimize early restenosis. Patients must refrain from future manipulation of their ear canal skin to prevent late restenosis, which can occur years after initial repair. References 1. Selesnick SNguyen TPEisenman DJ Surgical treatment of acquired external auditory canal atresia. Am J Otol 1998;19123- 130PubMedGoogle Scholar 2. Slattery WHSaadat P Postinflammatory medial canal fibrosis. Am J Otol 1997;18294- 297PubMedGoogle Scholar 3. Roland PS Chronic external otitis. Ear Nose Throat J 2001;80(suppl 6)12- 16PubMedGoogle Scholar 4. Tos MBale V Postinflammatory acquired atresia of the externa auditory canal: late results of surgery. Am J Otol 1986;7365- 370PubMedGoogle Scholar 5. Lavy JFagan P Chronic stenosing external otitis/postinflammatory acquired atresia: a review. Clin Otolaryngol 2000;25435- 439PubMedGoogle ScholarCrossref 6. El-Sayed Y Acquired medial canal fibrosis. J Laryngol Otol 1998;112145- 149PubMedGoogle ScholarCrossref 7. Noyek AMKirsh JCGreyson HD et al. The clinical significance of radionuclide bone and gallium scanning in osteomyelitis of the head and neck. Laryngoscope 1984;94(suppl 34)1- 21PubMedGoogle ScholarCrossref 8. Birman CSFagan PA Medial canal stenosis—chronic stenosing externa otitis. Am J Otol 1996;172- 6PubMedGoogle ScholarCrossref 9. Banthia VSelesnick SH Mitomycin-C in the postsurgical ear canal. Otolaryngol Head Neck Surg 2003;128882- 886PubMedGoogle ScholarCrossref
Journal
Archives of Otolaryngology - Head & Neck Surgery
– American Medical Association
Published: Jun 1, 2006
Keywords: diagnostic radiologic examination,radiology specialty,fibrosis
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