This surgery was most likely a canal-wall-down tympanomastoidectomy often performed for a benign ear tumor called cholesteatoma or a severe chronic draining ear. This surgery essentially removes all the bone from behind the ear (mastoid) and ear canal back wall. Depending on how aggressive the surgery, the eardrum and middle ear bones (malleus, stapes, and incus) may also be removed.
With such surgery, the ear canal now 2-3 times larger than before, is prone to developing earwax impaction and requires surgical debridement or removal every 4-6 months for the rest of the patient's life.
If surgical debridement is not performed regularly in such patients, infection may set in.
With such infection, ear drops can be used as described in the story, but such treatment is bound to fail until ear canal debridement of all earwax is first performed.
What I suspect is that this poor patient did not get her ear cleaned out regularly resulting in infected earwax. A fly noting the foul cesspool located in a dark, humid environment of this enlarged ear canal probably thought this the perfect place to lay eggs and allow a maggot infestation to occur.
Gross, horrid, and astounding I know...
However, medicinal maggot therapy is actually used in hospitals... Why?
Because maggots are apparently WAY better than a surgeon in certain situations at removing dead infected tissue with or without antibiotics.
It is entirely possible that given time, the maggots might have cleaned and removed the infection that was probably present in this patient's ear. However, unlike medical-grade maggots which are "sterilized" prior to use, "natural"maggots probably harbor other microbes that could cause a secondary infection.
Such medicinal maggots can be purchased for wound control with a prescription. Monarch Labs is the exclusive USA supplier of medicinal maggots which the FDA considers a "medical device."
Here is a video produced by National Geographic on maggot therapy.
92-year-old has 57 maggots removed from ear, family sues nursing home. CBS News 11/30/12