Introduction: The bone-anchored hearing aid (BAHA) can treat hearing loss in a variety of clinical situations. This device converts sound energy into vibrations, which are delivered to the cochlea. Occasionally skin/scar overgrowth may cover the abutment. Not only does this overgrowth interfere with affixing the BAHA to the abutment, but it also may attenuate the conduction of vibrations to the cochlea. Surgical scar revision/excision has been used previously to treat this problem. Clobetasol, a steroid cream for the treatment of psoriasis, can reduce skin overgrowth. Objective: We reviewed our experience with skin overgrowth involving the abutment sit and the efficacy of clobetasol to treat this problem. Hypothesis: Clobetasol (0.05%) can reduce skin overgrowth so that BAHA patients may resume use. Methods: The authors conducted a retrospective analysis of patients having undergone BAHA abutment implantation from January 2003 through December 2006. Results: Eighty-eight patients (2 patients received bilateral BAHAs) were reviewed. Twenty of 90 sites (22%) developed overgrowth. Thirteen of 20 sites were treated with Clobetasol. The overgrowth resolved in 11 of 13 (85%) sites following treatment. Conclusion: Clobetasol is an effective treatment for abutment skin/scar overgrowth. Not only does it allow patients to resume BAHA use, but it also may improve vibration conduction to the cochlea and obviate the need for scar revision. Eighty-eight patients (86 unilateral, 2 bilateral) underwent abutment implantation. Mean age was 42.5 years (range 3-85 years). Male:female ratio was 38/50. FTSG:STSG ratio was 26/64. The median onset of skin overgrowth was 8 weeks, ranging from 2 weeks to 19 weeks (Figure 3). Wound complications occurred in 25/90 (28%) implantation sites. Skin overgrowth was the most common complication occurring in 20/90 (22%) sites. This occurred in 2 of 26 FTSG sites versus 18 of 64 STSG sites. Incomplete skin graft survival occurred in 11 of 90 sites (12%), and skin overgrowth occurred in 7 of these patients. Clobetasol cream 0.05% was applied to 13 of 20 sites. The remaining 7 sites were treated with skin excision. Of the sites treated with clobetasol, resolution of skin overgrowth (Figure 4) occurred in 11 of 13 sites (85%). The mean resolution time was 7 weeks, ranging from 3 weeks to 3 months. Of the 7 sites treated with primary overgrowth excision, 4 required multiple revision procedures. The development of skin overgrowth was independent of age, sex, and co-morbidities known to impair wound healing (e.g. diabetes mellitus). Patients with incomplete skin graft survival were significantly more likely to develop skin overgrowth (p=0.0017). Results 1. Proops DW. The Birmingham bone anchored hearing aid programme: surgical methods and complications. J Laryngol Otol 1996; 110 (Suppl 21): 7-12. 2. Falcone MT, Labadie RF. An alternate approach for surgical dressing of bone-anchored hearing aid abutment sites. Laryngoscope 2007; 117(4):614-616. 3. Snik FM, Mylanus E, Cremers W. The bone-anchored hearing aid: a solution for previously unresolved otologic problems. Otolaryngol Clin North Am 2001; 34(2): 365-372. 4. Entific Medical Systems. http://www.entific.com 5. House JW, Kutz JW. Bone anchored hearing aids: incidence and management of postoperative complications. Otol Neurotol 2007; 28: 213-217. 6. Valencia IC, Kerdel FA. Topical Glucocorticoids. Fitzpatrick Dermatology in General Medicine, Sixth Ed 2003; 243: 2323-2328. 7. Hengge UR, Ruzicka T, Schwartz RA, Cork MJ. Adverse effects of topical glucocorticoids. J Am Acad Dermatol 2006; 54(1): 1-15. 8. Shirazi MA, Marzo SJ, Leonetti JP. Perioperative complications with the bone-anchored hearing aid. Otolaryngol Head Neck Surg 2006; 134: 236-239. 9. Reyes RA, Tjellstrom A, Granstrom G. Evaluation of implant losses and skin reactions around extraoral boneanchored implants: a 0to 8-year follow-up. Otolaryngol Head Neck Surg 2000; 122: 272-276. 10. Doshi J, Karagama Y, Buckley D, Johnson I. Observational study of bone-anchored hearing aid infection rates using different post-operative dressings. J Laryngol Otol 2006 May 19; 1-3 (Epub ahead of print). 11. Zeitoun H, De R, Thompson SD, Proops DW. Osseointegrated implants in the management of childhood ear abnormalities: with particular emphasis on complications. J Laryngol Otol 2002; 116(2): 87-91. 12. Snyder MC, Moore GF, Johnson PJ. The use of full-thickness skin grafts for the skin-abutment interface around bone-anchored hearing aids. Otol Neurotol 2003; 24: 255-258. 13. Reddy TN, Dutt SN, Gangopadhyay K. Modified incisions for reduction of soft tissue for one-stage, bone-anchored hearing aid implantation. Laryngoscope 2000; 110: 1584-1585. 14. Woolford TJ, Morris DP, Saeed SR, Rothera MP. The implant-site split-skin graft technique for the bone-anchored hearing aid. Clin Otolaryngol Allied Sci 1999; 24(3): 177-180. 15. Lekakis GK, Najuko A, Gluckman PG. Wound related complications following full thickness skin graft versus split thickness skin graft on patients with bone anchored hearing aids. Clin Otolaryngol 2005; 30(4): 324-327. Bibliography A retrospective chart analysis was performed on all patients undergoing BAHA abutment implantation between January 2003 through December 2006. The surgical technique involves elevating an inferiorly based split thickness skin graft (STSG) or full thickness skin graft (FTSG) over the mastoid bone. The subcutaneous tissue is excised down to the periosteum. The skin is undermined around the border of the operative site (Figure 1). The border is sutured to the periosteum (Figure 2). The titanium abutment implant is secured into bone. The skin graft is placed around the abutment and sutured to the surrounding skin. Post-operative dressing consisted of a bolster or healing cap. The dressing was applied for 1 week. The BAHA was first placed on the abutment at 8 weeks. At presentation with skin overgrowth involving the abutment, patients underwent either medical or surgical treatment. Medical treatment included clobetasol cream 0.05% applied topically to the affected area twice daily until resolution of overgrowth. Surgical treatment was comprised of excising the skin overgrowth around the abutment down to the underlying periosteum. This was generally performed under local anesthesia in the clinic setting. Overgrowth excision was also performed on cases that were refractory to medical therapy. Recurrent skin overgrowth following excision was treated either with topical clobetasol or revision skin excision. The revision skin excision was performed similarly to the primary excision. Methods and Materials Figure 3. BAHA abutment with skin overgrowth. Figure 1. Skin undermined to reduce nearby soft tissue. Figure 4. Resolution of skin overgrowth with clobetasol. Clobetasol is an effective treatment of bone anchored hearing aid abutment skin overgrowth. Reducing this overgrowth enables patients to resume use of the BAHA. It may also obviate the need for scar excision/revision as well as improve vibration conduction to the cochlea. Patient education regarding skin overgrowth can lead to early detection and treatment and minimize delay of BAHA use. Conclusions Introduction The bone anchored hearing aid (BAHA) is useful in treating hearing loss patients with a variety of problems including fixed conductive loss and unilateral sensorineural hearing loss. The hearing aid is mounted to a titanium implant abutment placed behind the ear. The hearing aid converts sound energy into vibrations which are delivered to the cochlea. This hearing aid may be removed from the abutment in a similar manner in which a traditional hearing aid is removed from the ear. Occasionally skin or scar overgrowth involving the abutment inhibit the patient’s ability to fasten the BAHA adequately. Clobetasol is a steroid cream that is FDA approved for the treatment of psoriasis. This drug has been used in the treatment of BAHA abutment skin over- growth, however its efficacy is not clear. The primary outcome measure is to determine the benefit of clobetasol in reducing skin/scar overgrowth such that a patient may adequately affix the BAHA to the abutment. Figure 2. Skin sutured to periosteum of donor site.