What is a costalectomy?

Answer 1

The word is misspelled, it should be costectomy.

Costectomy definition: excision of part or all of a rib.

The confusion comes from the word being misspelled in the following quote (along with at least one more misspelling):

"One [event] is the discovery of the anesthetic properties of chloroform [in 1847] by James Simpson of Scotland. Following the reports of [William] Morton's demonstration [1846], he tried ether but, dissatisfied, searched for a substitute and came upon chlorophorm. He was an obstetrician. His use of anesthesia to alleviate the pains of childbirth was violently opposed by the Scottish clergy on the ground that pain was ordained by the scriptural command, "In sorrow thou shalt bring forth children", and that it was impious to attempt to avert it by anesthetic agents. And it was Simpson who stilled this opposition by his own famous quotation from scripture; he pointed out that when Eve was born, God cast Adam into deep sleep before performing upon him the notable costalectomy. Anesthesia was thus permissible by scriptural precedent."

― Howard Wilcox Haggard