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Papio species as an animal model for neurotologic surgery
P126
Otolaryngology Head and Neck Surgery August 1996
Scientific Sessions- - Tuesday
Poster 8
Fixation of the Cochlear Implant Cable: An Objectlve Comparison of Techniques SHISHIR N. SHETH, M D (presenter),and T H O M A S J. BALKANY, MD, FACS, Miami, Fla.
Objective: Extrusion of a cochlear implant electrode is an infrequent but significant problem reported in an estimated 1% to 5% of cases. For this reason, many different techniques have been developed to stabilize the implant cable. The primary aim of this study was to evaluate the intrinsic resistance to extrusional forces of two electrode designs and to quantify and compare the efficacy of three currently used fixation techniques. Methods: Nucleus Mini-22 and Clarion 1.2 cochlear implant electrodes were inserted through a standard mastoidfacial recess-cochleostomy approach in formalin-preserved human temporal bones. Implant cables were stabilized by one of the following methods: split incus bridge technique, titanium clip, or ionomeric cement. In 175 trials, a tensiometer was used to measure the tiny forces necessary to dislodge the implanted electrode array for each of the different stabilization methods and a control condition in which implants were not stabilized. Results: All three techniques demonstrated statistically significant stabilization of the electrode array in comparison with controls, lonomeric cement was superior to both the split incus bridge technique and titanium clip. There was no significant difference between the split incus bridge and titanium clip techniques. Conclusions: In this short-term implant cadaver model, ionomeric cement was the strongest method of stabilization of a cochlear implant cable to help avoid electrode displacement. Although uncommon, even partial extrusion of a n implanted electrode is associated with significant morbidity and might be easily avoided by these techniques for implant cable stabilization.
anatomy, including pneumatization of the mastoid bone, location and course of the sigmoid sinus and jugular bulb, course of the facial nerve, measurements of the ossicles and tympanic membrane, length of the internal auditory canal, and measurements of the vestibular and cochlear nerves. Results: The observations of this anatomic study are presented in detail with accompanying photography. This information is not currently available in the veterinary literature or atlases of the Papio species. Conclusion: The anatomy of the temporal bone and cerebellopontine angle of the Papio species, including the size, location, and configuration are remarkably similar to that of human beings. Because of these similarities, we conclude that the Papio species is a suitable animal model for neurotologic surgery. P o s t e r 10 Inner Ear Melanocytes: Ethnic Differences DANIEL J. LEEMAN, MD (presenter), SUJANA S, CHANDRASEKHAR, MD, a n d HOSAKERE K. CHANDRASEKHAR, MD, Newark, N.J., a n d New York, N.Y.
The role melanocytes play in the inner ear is an intriguing area of otobiologic investigation. Ethnicity may be an important factor in the quantity and distribution of inner ear melanocytes, similar to that which has been described for epidermal melanocytes. This study quantifies the density of melanocytes in: 12 whites, 9 blacks, and 5 Hispanics. For each case each investigator was blinded, and the midmodiolar section was studied. Using a grading system from 0 to 4+, melanocytes at the modiolus, osseous spiral lamina, stria vascularis, Reissner's membrane, and endolymphatic duct and sac were counted. The results indicate that blacks and Hispanics have a greater density of inner ear melanocytes than whites. The functional and clinical significance of this finding remains to be defined. Poster 11
M A R A JEAN DAIDONE, M D (presenter),MOISES A. ARRIAGA, MD, and DAVID A. CARRIER, MD, San Antonio, Tex.
The Effect of Acidic Flbroblast Growth Factor and Live Yeast Cell Derivative on Tympanic M e m b r a n e Regeneration in a Rat Model STEVEN A. GOLDMAN, MD (presenter), STEPHEN P, CASS, MD, JILL SIEGFRIED, a n d PAUL SCOLIERI, BS, Allison Park, a n d Pittsburgh, Pa,
Objective: A suitable animal model for neurotologic surgery is a prerequisite for formal investigation of new cerebellopontine angle nerve substitution procedures. This comparative anatomic study evaluated a promising animal model for neurotologic surgical procedures. Methods: Preliminary temporal bone dissections were performed on cat, dog, pig, and baboon specimens. Because of comparable size and anatomic structure, detailed radiographic and dissection studies were then performed on the Papio species (baboon). Preoperative CT scanning followed by surgical dissections via the translabyrinthine, middle fossa, and retrosigmoid approaches were performed on five specimens. Observations were made of the surgical landmarks and
Objective: Current treatment of chronic tympanic membrane perforations is surgical. Recent studies utilizing various polypeptide growth factors to accelerate closure of acute and chronic tympanic membrane perforations in model systems have produced mixed results. This study evaluates the effect of acidic fibroblast growth factor (AFGF) and live yeast cell derivative (LYCD) on the rate of healing of acute tympanic membrane perforations in a rat model. Methods: Fifty rats had both ears separately randomized in a blinded fashion to receive AFGF in one of three concentrations, LYCD, or a control solution. Rats initially underwent subtotal removal of the tympanic membranes bilaterally. The solutions were applied to the randomized ears
Poster 9
Paplo Species as an Animal Model for Neurotologlc Surgery
Otolaryngology Head and Neck Surgery August 1996
Scientific Sessions- - Tuesday
Poster 8
Fixation of the Cochlear Implant Cable: An Objectlve Comparison of Techniques SHISHIR N. SHETH, M D (presenter),and T H O M A S J. BALKANY, MD, FACS, Miami, Fla.
Objective: Extrusion of a cochlear implant electrode is an infrequent but significant problem reported in an estimated 1% to 5% of cases. For this reason, many different techniques have been developed to stabilize the implant cable. The primary aim of this study was to evaluate the intrinsic resistance to extrusional forces of two electrode designs and to quantify and compare the efficacy of three currently used fixation techniques. Methods: Nucleus Mini-22 and Clarion 1.2 cochlear implant electrodes were inserted through a standard mastoidfacial recess-cochleostomy approach in formalin-preserved human temporal bones. Implant cables were stabilized by one of the following methods: split incus bridge technique, titanium clip, or ionomeric cement. In 175 trials, a tensiometer was used to measure the tiny forces necessary to dislodge the implanted electrode array for each of the different stabilization methods and a control condition in which implants were not stabilized. Results: All three techniques demonstrated statistically significant stabilization of the electrode array in comparison with controls, lonomeric cement was superior to both the split incus bridge technique and titanium clip. There was no significant difference between the split incus bridge and titanium clip techniques. Conclusions: In this short-term implant cadaver model, ionomeric cement was the strongest method of stabilization of a cochlear implant cable to help avoid electrode displacement. Although uncommon, even partial extrusion of a n implanted electrode is associated with significant morbidity and might be easily avoided by these techniques for implant cable stabilization.
anatomy, including pneumatization of the mastoid bone, location and course of the sigmoid sinus and jugular bulb, course of the facial nerve, measurements of the ossicles and tympanic membrane, length of the internal auditory canal, and measurements of the vestibular and cochlear nerves. Results: The observations of this anatomic study are presented in detail with accompanying photography. This information is not currently available in the veterinary literature or atlases of the Papio species. Conclusion: The anatomy of the temporal bone and cerebellopontine angle of the Papio species, including the size, location, and configuration are remarkably similar to that of human beings. Because of these similarities, we conclude that the Papio species is a suitable animal model for neurotologic surgery. P o s t e r 10 Inner Ear Melanocytes: Ethnic Differences DANIEL J. LEEMAN, MD (presenter), SUJANA S, CHANDRASEKHAR, MD, a n d HOSAKERE K. CHANDRASEKHAR, MD, Newark, N.J., a n d New York, N.Y.
The role melanocytes play in the inner ear is an intriguing area of otobiologic investigation. Ethnicity may be an important factor in the quantity and distribution of inner ear melanocytes, similar to that which has been described for epidermal melanocytes. This study quantifies the density of melanocytes in: 12 whites, 9 blacks, and 5 Hispanics. For each case each investigator was blinded, and the midmodiolar section was studied. Using a grading system from 0 to 4+, melanocytes at the modiolus, osseous spiral lamina, stria vascularis, Reissner's membrane, and endolymphatic duct and sac were counted. The results indicate that blacks and Hispanics have a greater density of inner ear melanocytes than whites. The functional and clinical significance of this finding remains to be defined. Poster 11
M A R A JEAN DAIDONE, M D (presenter),MOISES A. ARRIAGA, MD, and DAVID A. CARRIER, MD, San Antonio, Tex.
The Effect of Acidic Flbroblast Growth Factor and Live Yeast Cell Derivative on Tympanic M e m b r a n e Regeneration in a Rat Model STEVEN A. GOLDMAN, MD (presenter), STEPHEN P, CASS, MD, JILL SIEGFRIED, a n d PAUL SCOLIERI, BS, Allison Park, a n d Pittsburgh, Pa,
Objective: A suitable animal model for neurotologic surgery is a prerequisite for formal investigation of new cerebellopontine angle nerve substitution procedures. This comparative anatomic study evaluated a promising animal model for neurotologic surgical procedures. Methods: Preliminary temporal bone dissections were performed on cat, dog, pig, and baboon specimens. Because of comparable size and anatomic structure, detailed radiographic and dissection studies were then performed on the Papio species (baboon). Preoperative CT scanning followed by surgical dissections via the translabyrinthine, middle fossa, and retrosigmoid approaches were performed on five specimens. Observations were made of the surgical landmarks and
Objective: Current treatment of chronic tympanic membrane perforations is surgical. Recent studies utilizing various polypeptide growth factors to accelerate closure of acute and chronic tympanic membrane perforations in model systems have produced mixed results. This study evaluates the effect of acidic fibroblast growth factor (AFGF) and live yeast cell derivative (LYCD) on the rate of healing of acute tympanic membrane perforations in a rat model. Methods: Fifty rats had both ears separately randomized in a blinded fashion to receive AFGF in one of three concentrations, LYCD, or a control solution. Rats initially underwent subtotal removal of the tympanic membranes bilaterally. The solutions were applied to the randomized ears
Poster 9
Paplo Species as an Animal Model for Neurotologlc Surgery