Final answer:
Conductive hearing loss occurs when spongy bone forms around the stapes-oval window junction, hindering sound transmission to the inner ear.
Step-by-step explanation:
The condition where spongy bone forms around the junction of the stapes and the oval window, resulting in the stapes being unable to conduct sound vibrations to the inner ear, causes a type of hearing loss known as conductive hearing loss. This is due to damage to the bones of the middle ear, specifically the stapes, which fails to vibrate and transmit sound waves properly to the cochlea. Treatment options may include hearing aids or surgery, depending on the severity of the hearing loss.