Canal wall reconstruction with Mimix hydroxyapatite cement: results in an animal model and case study.
OBJECTIVE
To assess Mimix hydroxyapatite cement for its applicability in canal wall reconstruction using the gerbil as a canal wall model. A case is presented to illustrate a novel technique of canal wall reconstruction using Mimix on the basis of the findings of our animal research.


METHODS
This was a preclinical study.


METHODS
Ten Mongolian gerbils were implanted with Mimix, with the left side used to simulate mastoid obliteration and the right side used to simulate canal wall reconstruction. Pre- and postsurgery auditory-evoked brainstem responses were used to assess ototoxicity, and hematoxylin-eosin staining of histologic sections was used to assess inflammatory and foreign-body response and new bone formation.


RESULTS
Rapid wound healing was achieved with each of the nine animals evaluated, with no erythema, edema, or drainage. Inspection of the ear canal at the time of sacrifice revealed no signs of otitis media and no middle ear effusions. Microscopic examination showed no inflammatory response or foreign-body reaction, good mucosalization on the side of the implant facing the bulla, and minimal fibrosis adjacent to the skin. Eight of nine specimens showed new woven bone ingrowth at the bone implant interface, with active osteoblasts and viable lacunae cells. There were no apparent fractures in the implanted material.


CONCLUSIONS
Mimix hydroxyapatite cement is biocompatible and suitable for canal wall reconstruction in the animal model. The characteristics of this cement, namely its ability to set quickly in a moist environment, offer advantages over previously used cements for canal wall reconstruction.
Dornhoffer
John
J
Department of Otolaryngology/Head and Neck Surgery, University of Arkansas for Medical Sciences, 4301 West Markham, MS 543, Little Rock, AR 72205, USA. DornhofferJohnL@uams.edu
Simmons
Oliver
O
D000328:Adult; D000818:Animals; D001672:Biocompatible Materials; D017886:Durapatite; D004424:Ear Canal / Q000166:cytology / Q000601:surgery*; D005072:Evoked Potentials, Auditory; D005260:Female; D005849:Gerbillinae; D006801:Humans; D019919:Prosthesis Implantation; D016896:Treatment Outcome; D014945:Wound Healing / Q000502:physiology
D001672:Biocompatible Materials; D017886:Durapatite