Ann Otol Rhinal Laryngol99: 1990
COCHLEAR IMPLANT FLAP COMPLICATIONS ROBERT C. WANG, MD PATRICIA M. CHUTE, MA
SIMON C. PARISIER, MD SHARON A. HELLMAN, MA
MICHAEL H. WEISS, MD EDWARD SAURIS, MD
NEW YORK, NEW YORK
In a series of 52 patients who received cochlear implants, 4 patients suffered flap complications (7.7 % ). Theproblems encountered involved thepostauricular flap andwere usually minor in nature. None required explantation asa direct result ofthese complications. Flap ischemia in a patient withCogan's syndrome andvasculitis, twocases ofsuture extrusion withone having exposure ofthe implant, and a case ofreceiver unitmagnet extrusion repaired with a vascularized pericranial flap based upon temporalis muscle arepresented. Flapdesign in patients who have had postauricular incisions demands special consideration. Principles useful foravoiding complications aswell as their management are discussed. KEY WORDS - cochlear implant, postoperative complications, surgical flaps. channel device was performed in June 1988 by use of a standard anteriorly based flap. The immediate postoperative course was uneventful, and the external coil was applied 2 months later.
INTRODUCTION
Although the postauricular and parietal-occipital scalp skin areas are well vascularized, the conflicting demands of flap viability and optimal coil transmission through thinned skin compressed by magnetic forces in cochlear implant recipients can cause flap complications. This is especially true in instances of already compromised circulation, such as from prior operation in the same region. I In a comprehensive survey of complications associated with the use of the Nucleus multichannel cochlear implant, Cohen et aP found 22 cases of flap breakdown or infection in a total of 459 operations. Nine of these required explantation. Eighty percent of flap complications transpired within the first three operations performed by individual surgeons. Nevertheless, even experienced operators must take care in designing and preparing skin flaps for cochlear implants, particularly in those patients with prior ear operations or cochlear implantation. A recent survey by Parisier et al (unpublished data, 1989) reveals 130 of 1,175 patients (11 %) had failed implants - including 19 % of 569 3MIHouse devices and 3.5 % of 606 Nucleus implants - the majority of whom were candidates for reimplantation. This paper presents four skin flap complications encountered by the senior author (S.C.P.) in a series of 52 cochlear implants (7.7 %).
In December 1988, extrusion of the internal magnet through the center of the otherwise intact skin flap was noted (Fig lA). Revision was accomplished by extending the anterior limb of the original incision to allow elevation of a large pericranial flap based upon the posterior half of the temporalis muscle (Fig IB). The internal coil and magnet were rotated anteriorly and secured away from the skin perforation, which was oversewn. Complete coverage of the receiver unit with the thin pericranial flap rotated posteroinferiorly was performed to prevent reextrusion (Fig 1C). After an episode of skin erythema overlying the internal magnet 3 months after revision, treated by reducing magnet strength and wearing time, the patient was doing well 14 months following pericranial flap repair.
Case 2. A 29-year-old man in 1971 developed fluctuating bilateral sensorineural hearing loss, vertigo, and tinnitus. Cogan's syndrome was diagnosed in 1974 with the discovery of interstitial keratitis. After progression to binaural deafness, left cochlear implantation with an original House Sigma singlechannel device was performed in 1978. Despite steroid treatment, in 1980 his vasculitis worsened, with Raynaud's disease, congestive heart failure caused by an isolated left main coronary artery stenosis requiring a coronary bypass operation, and a transient ischemic attack with central aphasia and pulse deficits of the left upper extremity. He continues to this day to receive steroid therapy.
CASE REPORTS
Case 1. A 50-year-old woman presented with a history of binaural sensorineural hearing loss that had progressed for 5 years, until 8 months prior, when sudden worsening occurred and hearing aids were no longer helpful. An audiogram confirmed binaural deafness, with magnetic resonance imaging and computed tomography (CT) results being normal, without cochlear dysplasia or ossification. Cochlear implantation with a Nucleus 22 multi-
In 1983, the patient underwent right cochlear implantation with a House/3M single-channel Alpha magnetized device by the senior author (S.C.P.) after preoperative assessment with an audiogram,
From the Department of Otolaryngology, Manhattan Eye, Ear and Throat Hospital, New York, New York. Presented at the meeting of the American Otological Society, Inc, Palm Beach, Florida, April 28-29, 1990. REPRINTS - Robert C. Wang, MD, Dept of Otolaryngology, Manhattan Eye, Ear and Throat Hospital, 210 E 64th St, New York, NY 10021.
791
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Wang et al, Cochlear Implant Flap Complications
Fig 1. (Case 1) A) Implant extrusion. B) Illustration depicting elevation of pericranial flap based on posterior temporalis muscle and repositioning of receiver device. C) Illustration showing coverage of receiver device with pericranial flap.
electronystagmography, and a CT scan. Although his communication skills were improved, the patient was unable to use a telephone, since he lacked any open-set discrimination. After extensive discussion and left promontory stimulation showing good responses, the patient elected to upgrade the left ear device with a Nucleus 22 multichannel implant in
May 1987. In order to accommodate the larger Nucleus device, a separate, posterosuperiorly staggered incision was used to create an anteriorly based skin flap (Fig 2A). The area between the old and new incisions became increasingly cyanotic during the next 2 weeks (Fig 2B). After superficial sloughing, this area healed well by secondary inten-
Downloaded from aor.sagepub.com at Harvard Libraries on June 27, 2015
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Wang et al, Cochlear Implant Flap Complications
Fig 2. (Case 2) A) Design of flap incision, staggered posterosuperiorly from previous cochlear implant incision. B) Necrosis of skin between new and old incisions on postoperative day 10.
tion, although alopecia remains. He has had no further flap breakdown or changes since. Cases 3 and 4. These cases represent the extrusion of 0 silk suture material used in securing the internal coil. A 4-year-old girl (case 3) with mild right upper extremity cerebral palsy and congenital binaural deafness underwent left cochlear implantation with a Nucleus 22 multichannel device in June 1988. Four months subsequently, a small area of inflammation and skin breakdown was noted over the internal magnet. The defect was explored in the office and a 0 silk suture removed, resulting in prompt healing within 2 weeks and no further problems since. A 27-year-old man (case 4) with congenital deafness due to maternal rubella infection underwent insertion of a House/3M single-channel cochlear implant into the right ear in April 1983 after preoperative assessment including an audiogram, aided and unaided, and a CT scan of the temporal bones. Four months postoperatively, after he had used the implant for 3 months, a small abscess overlying the internal magnet was drained and cauterized with silver nitrate. Over the ensuing 3 months, this area developed granulation tissue and continual dehiscence resulting in exposure of the receiver unit despite aggressive local wound care. Finally, a 0 silk suture extruded and was removed from this site, ac-
companied by prompt healing within a month. Of note, in May 1984 the implant abruptly ceased operating, and revision 2 months later revealed a fractured implant ground wire. DISCUSSION
In creating a skin flap for cochlear implantation,
the portion of the flap overlying the internal coil should be made as thin as possible, usually less than 6 mm", to allow optimal transmission and magnet holding. To avoid more widespread thinning of the flap than is necessary, methylene blue is instilled subcutaneously at the anticipated receiver unit location during the flap design. However, excessive thinning of the flap can result in skin breakdown from magnet pressure. In younger children, who have inherently thinner scalp skin, elevation of the postauricular muscle layer in continuity with the skin flap protects the flap, yet keeps it thin enough to transmit well. Proper alignment of the external and internal coils is also important. In case 1, a contributing cause of implant extrusion may have been a failure of the flat receiver device to conform to the skull curvature, so that one edge of the device exerted excessive pressure on the overlying flap. The design of the flap incision must be tailored to the individual patient, particularly in cases of revision or after prior operation in the region (Fig 3).
Downloaded from aor.sagepub.com at Harvard Libraries on June 27, 2015
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Wang et al, Cochlear Implant Flap Complications
Fig 3. Design of flap incisions. A) Standard anteriorly based flap. B) Inferiorly based flap incorporating previous postauricular incision. C) Inferiorly based flap after prior cochlear implant where larger flap is needed. D) Anterior extension incorporating superior portion of standard incision to raise pericranial flap.
We agree with Harris and Cueva,' who reported a case of flap necrosis similar to that in case 2 in a patient who had a postauricular incision for mastoidectomy, that when prior incisions limit the usual superficial temporal artery supply to an anteriorly based flap, it is best to place incisions that take advantage of the occipital artery, and to a lesser extent, the postauricular artery. It is likely that in case 2, skin atrophy from chronic steroid therapy and relative ischemia due to vasculitis were additional adverse factors. The flap should be broad-based to prevent venous congestion. While the recommended minimal distance of the proposed incision line to the edge of the implant varies according to author from 0.5 ern (Doyle and Pijl") and 1.0 ern (House") to 2.0 em (Schindler et al") - it is our impression that the incision line migrates toward the implant with scar contracture in the typical anteriorly based flap, and therefore the distance from incision line to implant should be no less than 2.0 cm. Delicate handling of the flap and keeping it moistened are essential, as is the use of a closed suction drainage system to prevent seroma. The pericranial flap, based 'anteriorly on the supratrochlear and supraorbital vessels, is used to support the brain and act as a bed for split thickness skin grafting after anterior skull base resection. Even after frequently receiving preoperative radio-
therapy to the region, this flap has had a reported overall success rate of 95 % .6 Pericranial flaps can also be based laterally on the temporalis muscle, supplied inferiorly in axial fashion by the two deep temporal arteries that are branches of the internal maxillary artery, and used to reconstruct lateral skull, ear, and face defects. 7-9 The use of a vascularized pericranial flap based upon the temporalis muscle was successful in preventing reextrusion of the internal magnet in the patient in case 1, who appeared to have especially delicate skin, as careful adjustment of magnet strengths and wear duration was necessary even after revision to prevent sustained reactive hyperemia. The pericranial flap is thin, pliable, and durable and can be raised with relative ease as well as with minimal cosmetic and functional morbidity. Finally, the use of permanent reactive suture in the form of 0 silk caused complications in two cases, in one causing a sustained inflammatory reaction with stitch abscess, granulation tissue, and implant exposure. Instead, 2-0 chromic catgut tied eccentrically to the receiver is recommended to secure implants. It is important to place knots away from the magnetized surface of the receiver unit, on which pressure from the external device could cause localized skin breakdown.
REFERENCES I. Harris JP, Cueva RA. Flap design for cochlear implantation: avoidance of a potential complication. Laryngoscope 1987; 97:755-7.
2. Cohen NL, Hoffman RA, Stroschein M. Medical or surgi-
cal complications related to the Nucleus multichannel cochlear implant. Ann Otol Rhinol Laryngol 1988;97(suppl 135):8-13. 3. Doyle PJ, Pijl S. Cochlear implant experience at the University of British Columbia. J OtolaryngoI1987;16:300-6.
Downloaded from aor.sagepub.com at Harvard Libraries on June 27, 2015
Wang et al, Cochlear Implant Flap Complications
795
7. Renner G, Davis WE, Templer J. Temporalis pericranial muscle flap for reconstruction of the lateral face and head. Laryngoscope 1984;94:1418-22.
4. House WF. Surgical considerations in cochlear implantation. Ann Otol Rhinol Laryngol 1982;91(suppl 91):15-20. 5. Schindler RA, Kessler DK, Rebscher SJ, [ackler RK, Merzenich MM. Surgical considerations and hearing results with the UCSF/Storz cochlear implant. Laryngoscope 1987;97:50-6.
8. Argenta LC, Friedman RJ, Dingman RO, Duus EC. The versatility of pericranial flaps. Plast Reconstr Surg 1985;76:695702. 9. Antonyshyn 0, Colcleugh RG, Hurst LN, Anderson C. The temporalis myo-osseous flap: an experimental study. Plast Reconstr Surg 1986;77:406-15.
6. Price JC, Loury M, Carson B, Johns ME. The pericranial flap for reconstruction of anterior skull base defects. Laryngoscope 1988;98:1159-64.
--FIFTH INTERNATIONAL SYMPOSIUM RECENT ADVANCES IN OTITIS MEDIA The Fifth International Symposium on Recent Advances in Otitis Media will be held May 20-23,1991, at the Sheraton Bal Harbour in Bal Harbour, Florida. For further information, contact David J. Lim, MD, 4331 University Hospitals Clinic, 456 W Tenth Avenue, Columbus, OH 43210; Phone: (614) 293-8103; Fax: (614) 293-5506.
THE DEAFNESS RESEARCH FOUNDATION OTOLOGICAL RESEARCH FELLOWSHIP FOR THIRD YEAR MEDICAL STUDENTS The Deafness Research Foundation's Otological Research Fellowship will be sponsored by a department of otolaryngology conducting otological research. Where a unique opportunity exists in a related discipline, the fellowship may be conducted in that discipline while maintaining liaison with the department of otolaryngology. The fellowship would be scheduled as a one-year block of time at the end of the third year of medical school, thus requiring a one-year leave of absence from the medical school curriculum. Applications for 1991 must be received by November 15, 1990. For more information, please contact Walter A. Petryshyn, MD, Medical Director, The Deafness Research Foundation, 9 East 38th Street, New York, NY 10016; (212) 684-6556.
Downloaded from aor.sagepub.com at Harvard Libraries on June 27, 2015
COCHLEAR IMPLANT FLAP COMPLICATIONS ROBERT C. WANG, MD PATRICIA M. CHUTE, MA
SIMON C. PARISIER, MD SHARON A. HELLMAN, MA
MICHAEL H. WEISS, MD EDWARD SAURIS, MD
NEW YORK, NEW YORK
In a series of 52 patients who received cochlear implants, 4 patients suffered flap complications (7.7 % ). Theproblems encountered involved thepostauricular flap andwere usually minor in nature. None required explantation asa direct result ofthese complications. Flap ischemia in a patient withCogan's syndrome andvasculitis, twocases ofsuture extrusion withone having exposure ofthe implant, and a case ofreceiver unitmagnet extrusion repaired with a vascularized pericranial flap based upon temporalis muscle arepresented. Flapdesign in patients who have had postauricular incisions demands special consideration. Principles useful foravoiding complications aswell as their management are discussed. KEY WORDS - cochlear implant, postoperative complications, surgical flaps. channel device was performed in June 1988 by use of a standard anteriorly based flap. The immediate postoperative course was uneventful, and the external coil was applied 2 months later.
INTRODUCTION
Although the postauricular and parietal-occipital scalp skin areas are well vascularized, the conflicting demands of flap viability and optimal coil transmission through thinned skin compressed by magnetic forces in cochlear implant recipients can cause flap complications. This is especially true in instances of already compromised circulation, such as from prior operation in the same region. I In a comprehensive survey of complications associated with the use of the Nucleus multichannel cochlear implant, Cohen et aP found 22 cases of flap breakdown or infection in a total of 459 operations. Nine of these required explantation. Eighty percent of flap complications transpired within the first three operations performed by individual surgeons. Nevertheless, even experienced operators must take care in designing and preparing skin flaps for cochlear implants, particularly in those patients with prior ear operations or cochlear implantation. A recent survey by Parisier et al (unpublished data, 1989) reveals 130 of 1,175 patients (11 %) had failed implants - including 19 % of 569 3MIHouse devices and 3.5 % of 606 Nucleus implants - the majority of whom were candidates for reimplantation. This paper presents four skin flap complications encountered by the senior author (S.C.P.) in a series of 52 cochlear implants (7.7 %).
In December 1988, extrusion of the internal magnet through the center of the otherwise intact skin flap was noted (Fig lA). Revision was accomplished by extending the anterior limb of the original incision to allow elevation of a large pericranial flap based upon the posterior half of the temporalis muscle (Fig IB). The internal coil and magnet were rotated anteriorly and secured away from the skin perforation, which was oversewn. Complete coverage of the receiver unit with the thin pericranial flap rotated posteroinferiorly was performed to prevent reextrusion (Fig 1C). After an episode of skin erythema overlying the internal magnet 3 months after revision, treated by reducing magnet strength and wearing time, the patient was doing well 14 months following pericranial flap repair.
Case 2. A 29-year-old man in 1971 developed fluctuating bilateral sensorineural hearing loss, vertigo, and tinnitus. Cogan's syndrome was diagnosed in 1974 with the discovery of interstitial keratitis. After progression to binaural deafness, left cochlear implantation with an original House Sigma singlechannel device was performed in 1978. Despite steroid treatment, in 1980 his vasculitis worsened, with Raynaud's disease, congestive heart failure caused by an isolated left main coronary artery stenosis requiring a coronary bypass operation, and a transient ischemic attack with central aphasia and pulse deficits of the left upper extremity. He continues to this day to receive steroid therapy.
CASE REPORTS
Case 1. A 50-year-old woman presented with a history of binaural sensorineural hearing loss that had progressed for 5 years, until 8 months prior, when sudden worsening occurred and hearing aids were no longer helpful. An audiogram confirmed binaural deafness, with magnetic resonance imaging and computed tomography (CT) results being normal, without cochlear dysplasia or ossification. Cochlear implantation with a Nucleus 22 multi-
In 1983, the patient underwent right cochlear implantation with a House/3M single-channel Alpha magnetized device by the senior author (S.C.P.) after preoperative assessment with an audiogram,
From the Department of Otolaryngology, Manhattan Eye, Ear and Throat Hospital, New York, New York. Presented at the meeting of the American Otological Society, Inc, Palm Beach, Florida, April 28-29, 1990. REPRINTS - Robert C. Wang, MD, Dept of Otolaryngology, Manhattan Eye, Ear and Throat Hospital, 210 E 64th St, New York, NY 10021.
791
Downloaded from aor.sagepub.com at Harvard Libraries on June 27, 2015
792
Wang et al, Cochlear Implant Flap Complications
Fig 1. (Case 1) A) Implant extrusion. B) Illustration depicting elevation of pericranial flap based on posterior temporalis muscle and repositioning of receiver device. C) Illustration showing coverage of receiver device with pericranial flap.
electronystagmography, and a CT scan. Although his communication skills were improved, the patient was unable to use a telephone, since he lacked any open-set discrimination. After extensive discussion and left promontory stimulation showing good responses, the patient elected to upgrade the left ear device with a Nucleus 22 multichannel implant in
May 1987. In order to accommodate the larger Nucleus device, a separate, posterosuperiorly staggered incision was used to create an anteriorly based skin flap (Fig 2A). The area between the old and new incisions became increasingly cyanotic during the next 2 weeks (Fig 2B). After superficial sloughing, this area healed well by secondary inten-
Downloaded from aor.sagepub.com at Harvard Libraries on June 27, 2015
793
Wang et al, Cochlear Implant Flap Complications
Fig 2. (Case 2) A) Design of flap incision, staggered posterosuperiorly from previous cochlear implant incision. B) Necrosis of skin between new and old incisions on postoperative day 10.
tion, although alopecia remains. He has had no further flap breakdown or changes since. Cases 3 and 4. These cases represent the extrusion of 0 silk suture material used in securing the internal coil. A 4-year-old girl (case 3) with mild right upper extremity cerebral palsy and congenital binaural deafness underwent left cochlear implantation with a Nucleus 22 multichannel device in June 1988. Four months subsequently, a small area of inflammation and skin breakdown was noted over the internal magnet. The defect was explored in the office and a 0 silk suture removed, resulting in prompt healing within 2 weeks and no further problems since. A 27-year-old man (case 4) with congenital deafness due to maternal rubella infection underwent insertion of a House/3M single-channel cochlear implant into the right ear in April 1983 after preoperative assessment including an audiogram, aided and unaided, and a CT scan of the temporal bones. Four months postoperatively, after he had used the implant for 3 months, a small abscess overlying the internal magnet was drained and cauterized with silver nitrate. Over the ensuing 3 months, this area developed granulation tissue and continual dehiscence resulting in exposure of the receiver unit despite aggressive local wound care. Finally, a 0 silk suture extruded and was removed from this site, ac-
companied by prompt healing within a month. Of note, in May 1984 the implant abruptly ceased operating, and revision 2 months later revealed a fractured implant ground wire. DISCUSSION
In creating a skin flap for cochlear implantation,
the portion of the flap overlying the internal coil should be made as thin as possible, usually less than 6 mm", to allow optimal transmission and magnet holding. To avoid more widespread thinning of the flap than is necessary, methylene blue is instilled subcutaneously at the anticipated receiver unit location during the flap design. However, excessive thinning of the flap can result in skin breakdown from magnet pressure. In younger children, who have inherently thinner scalp skin, elevation of the postauricular muscle layer in continuity with the skin flap protects the flap, yet keeps it thin enough to transmit well. Proper alignment of the external and internal coils is also important. In case 1, a contributing cause of implant extrusion may have been a failure of the flat receiver device to conform to the skull curvature, so that one edge of the device exerted excessive pressure on the overlying flap. The design of the flap incision must be tailored to the individual patient, particularly in cases of revision or after prior operation in the region (Fig 3).
Downloaded from aor.sagepub.com at Harvard Libraries on June 27, 2015
794
Wang et al, Cochlear Implant Flap Complications
Fig 3. Design of flap incisions. A) Standard anteriorly based flap. B) Inferiorly based flap incorporating previous postauricular incision. C) Inferiorly based flap after prior cochlear implant where larger flap is needed. D) Anterior extension incorporating superior portion of standard incision to raise pericranial flap.
We agree with Harris and Cueva,' who reported a case of flap necrosis similar to that in case 2 in a patient who had a postauricular incision for mastoidectomy, that when prior incisions limit the usual superficial temporal artery supply to an anteriorly based flap, it is best to place incisions that take advantage of the occipital artery, and to a lesser extent, the postauricular artery. It is likely that in case 2, skin atrophy from chronic steroid therapy and relative ischemia due to vasculitis were additional adverse factors. The flap should be broad-based to prevent venous congestion. While the recommended minimal distance of the proposed incision line to the edge of the implant varies according to author from 0.5 ern (Doyle and Pijl") and 1.0 ern (House") to 2.0 em (Schindler et al") - it is our impression that the incision line migrates toward the implant with scar contracture in the typical anteriorly based flap, and therefore the distance from incision line to implant should be no less than 2.0 cm. Delicate handling of the flap and keeping it moistened are essential, as is the use of a closed suction drainage system to prevent seroma. The pericranial flap, based 'anteriorly on the supratrochlear and supraorbital vessels, is used to support the brain and act as a bed for split thickness skin grafting after anterior skull base resection. Even after frequently receiving preoperative radio-
therapy to the region, this flap has had a reported overall success rate of 95 % .6 Pericranial flaps can also be based laterally on the temporalis muscle, supplied inferiorly in axial fashion by the two deep temporal arteries that are branches of the internal maxillary artery, and used to reconstruct lateral skull, ear, and face defects. 7-9 The use of a vascularized pericranial flap based upon the temporalis muscle was successful in preventing reextrusion of the internal magnet in the patient in case 1, who appeared to have especially delicate skin, as careful adjustment of magnet strengths and wear duration was necessary even after revision to prevent sustained reactive hyperemia. The pericranial flap is thin, pliable, and durable and can be raised with relative ease as well as with minimal cosmetic and functional morbidity. Finally, the use of permanent reactive suture in the form of 0 silk caused complications in two cases, in one causing a sustained inflammatory reaction with stitch abscess, granulation tissue, and implant exposure. Instead, 2-0 chromic catgut tied eccentrically to the receiver is recommended to secure implants. It is important to place knots away from the magnetized surface of the receiver unit, on which pressure from the external device could cause localized skin breakdown.
REFERENCES I. Harris JP, Cueva RA. Flap design for cochlear implantation: avoidance of a potential complication. Laryngoscope 1987; 97:755-7.
2. Cohen NL, Hoffman RA, Stroschein M. Medical or surgi-
cal complications related to the Nucleus multichannel cochlear implant. Ann Otol Rhinol Laryngol 1988;97(suppl 135):8-13. 3. Doyle PJ, Pijl S. Cochlear implant experience at the University of British Columbia. J OtolaryngoI1987;16:300-6.
Downloaded from aor.sagepub.com at Harvard Libraries on June 27, 2015
Wang et al, Cochlear Implant Flap Complications
795
7. Renner G, Davis WE, Templer J. Temporalis pericranial muscle flap for reconstruction of the lateral face and head. Laryngoscope 1984;94:1418-22.
4. House WF. Surgical considerations in cochlear implantation. Ann Otol Rhinol Laryngol 1982;91(suppl 91):15-20. 5. Schindler RA, Kessler DK, Rebscher SJ, [ackler RK, Merzenich MM. Surgical considerations and hearing results with the UCSF/Storz cochlear implant. Laryngoscope 1987;97:50-6.
8. Argenta LC, Friedman RJ, Dingman RO, Duus EC. The versatility of pericranial flaps. Plast Reconstr Surg 1985;76:695702. 9. Antonyshyn 0, Colcleugh RG, Hurst LN, Anderson C. The temporalis myo-osseous flap: an experimental study. Plast Reconstr Surg 1986;77:406-15.
6. Price JC, Loury M, Carson B, Johns ME. The pericranial flap for reconstruction of anterior skull base defects. Laryngoscope 1988;98:1159-64.
--FIFTH INTERNATIONAL SYMPOSIUM RECENT ADVANCES IN OTITIS MEDIA The Fifth International Symposium on Recent Advances in Otitis Media will be held May 20-23,1991, at the Sheraton Bal Harbour in Bal Harbour, Florida. For further information, contact David J. Lim, MD, 4331 University Hospitals Clinic, 456 W Tenth Avenue, Columbus, OH 43210; Phone: (614) 293-8103; Fax: (614) 293-5506.
THE DEAFNESS RESEARCH FOUNDATION OTOLOGICAL RESEARCH FELLOWSHIP FOR THIRD YEAR MEDICAL STUDENTS The Deafness Research Foundation's Otological Research Fellowship will be sponsored by a department of otolaryngology conducting otological research. Where a unique opportunity exists in a related discipline, the fellowship may be conducted in that discipline while maintaining liaison with the department of otolaryngology. The fellowship would be scheduled as a one-year block of time at the end of the third year of medical school, thus requiring a one-year leave of absence from the medical school curriculum. Applications for 1991 must be received by November 15, 1990. For more information, please contact Walter A. Petryshyn, MD, Medical Director, The Deafness Research Foundation, 9 East 38th Street, New York, NY 10016; (212) 684-6556.
Downloaded from aor.sagepub.com at Harvard Libraries on June 27, 2015
