myotomy vs surgical operation

myotomy and surgical operation both are nouns.

Word	Noun	Adjective	Verb	Adverb
myotomy	Yes	No	No	No
surgical operation	Yes	No	No	No

As nouns, surgical operation is a hypernym of myotomy; that is, surgical operation is a word with a broader meaning than myotomy:

myotomy: surgical incision or division of a muscle
surgical operation: a medical procedure involving an incision with instruments; performed to repair damage or arrest disease in a living body

Other hypernyms of myotomy include operation, surgery, surgical procedure, surgical process.

myotomy (noun)	surgical operation (noun)
surgical incision or division of a muscle	a medical procedure involving an incision with instruments; performed to repair damage or arrest disease in a living body