The Temporal Bone in Osteopetrosis

Auditory Ossicle Abnormalities and Hearing Loss in the Toothless (Osteopetrotic) Mutation in the Rat and Their Improvement After Treatment with Colony-Stimulating Factor-1

“…Hearing loss was present in tl rats, although ankylosis of the stapes footplate in the oval window, as observed in otosclerosis, was not. That abnormal development of ossicles can cause the hearing impairment in osteopetrosis has been postulated by many other authors (6‐8,10,27,29) . This hypothesis is supported by the significant improvement of hearing in CSF‐1–treated mutants.…”

“…That abnormal development of ossicles can cause the hearing impairment in osteopetrosis has been postulated by many other authors. (6)(7)(8)10,27,29) This hypothesis is supported by the significant improvement of hearing in CSF-1-treated mutants. Since the primitive calcified cartilage was significantly reduced and osteoclasts developed after CSF-1 treatment, our results suggest that the hearing loss in tl rats has most likely a conductive genesis.…”

“…Thus the lack of resorption in osteopetrosis prevents the remodeling of the endochondral layer and the thinning necessary for the stapes to develop its normal configuration. The shape of the incus and malleus is normal, but the marrow cavity seen in normal infants does not develop (7) . Therefore, the major changes in the auditory ossicles of osteopetrotic children are confined to the stapes and account for our emphasis on stapedial morphology in these studies of the tl rat.…”

Pathology of the otic capsule

“…The other layers were also thickened, most obviously in the periosteal layer. Myers and Stool (1969) noted greatly increased globuli interossei in the otic capsule of a one-and-a-half-year-old child with ostepetrosis. Altmann (1933) reported a childhood case where there were abnormalities of the endochondral and periosteal layers.…”

When bone becomes marble: Head and neck manifestations of osteopetrosis

“…An intermediate primitive form of the stapes between the ring shape of the fetus and the adult appearance has also been reported (6). Variations in the histological characteristics of the otic capsule ranging from a normal endochondral layer to abnormal blue staining have also been described (18). Milroy and Michaels (15) reported thickening of all three layers of the otic capsule with an increase in the interossei globuli.…”