Demineralized bone matrix as an alternative for mastoid obliteration and posterior canal wall reconstruction: results in an animal model.
OBJECTIVE
This study was conducted to evaluate the use of Grafton human demineralized bone matrix as a graft material for mastoid cavity obliteration and canal wall reconstruction in an animal model.


BACKGROUND
Canal wall down procedures in the treatment of cholesteatoma may result in a problematic mastoid cavity. Elimination of the mastoid cavity by obliteration or canal wall reconstruction can prevent or correct this problem. Many techniques and implant materials have been used for this application, yet no single material has proven to be ideal.


METHODS
Athymic rats received tympanic bulla obliteration and lateral bulla wall reconstruction utilizing the Grafton Putty and Flex formulations, respectively. Wound healing was monitored twice a week. Auditory brainstem evoked responses were obtained 8 weeks after implantation. Nine weeks after implantation, the animals were killed, and histologic sections were prepared. A histologic bone formation score (range 0-4) was determined for each implant.


RESULTS
Wound healing occurred without complication. Auditory brainstem response thresholds (average 23.5) fell within the normal range for all ears tested. The average histologic bone formation score for all implants was 3.7. The average scores for obliteration implants and wall reconstruction implants were 3.5 and 3.9, respectively. All wall reconstruction implants underwent partial or total collapse into the bulla.


CONCLUSIONS
The high level of bone formation obtained by the use of Grafton implants in this study makes this material a promising resource for use in mastoid obliteration. The use of the material for canal wall reconstruction will likely require a sturdier preparation to prevent collapse into the mastoid cavity.
Leatherman
B D
BD
Department of Otolaryngology/Head and Neck Surgery, University of Arkansas for Medical Sciences, 4301 West Markham, Slot 543, Little Rock, AR 72205-7199, U.S.A.
Dornhoffer
J L
JL
Fan
C Y
CY
Mukunyadzi
P
P
D000818:Animals; D001309:Auditory Threshold / Q000502:physiology; D001672:Biocompatible Materials; D018775:Bone Demineralization Technique / Q000379:methods*; D001857:Bone Matrix / Q000166:cytology / Q000637:transplantation*; D018424:Cholesteatoma, Middle Ear / Q000601:surgery*; D004195:Disease Models, Animal; D004424:Ear Canal / Q000601:surgery*; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology; D005260:Female; D006309:Hearing / Q000502:physiology; D008416:Mastoid / Q000601:surgery*; D010011:Osteocytes / Q000166:cytology; D010012:Osteogenesis / Q000502:physiology; D019736:Prostheses and Implants; D051381:Rats; D017207:Rats, Sprague-Dawley; D014945:Wound Healing
D001672:Biocompatible Materials