What noun is "using novel techniques" modifying? Is there a noun its modifying? If it's an adverbial modifier... what is it referring to? There is no 'event of the treatment' in this sentence.
Why it cannot modify the verb "treated" ? Between the following two sentences, what is the underlying principle which makes one sentence correct and the other one wrong? Kindly elaborate.
Last night our air conditioner broke, causing great consternation.
The patient's rare disease was treated, using novel techniques.