Maryland has the highest concentration of outpatient surgery centers in the nation, a rank that represents a rapidly growing movement of doctors spinning off their own businesses as lightning-fast technology has made overnight hospital stays for some procedures obsolete.

The Foundation for Ambulatory Surgery in America reports that Maryland has the most facilities per capita - 352 surgery centers in all - followed by Idaho, Washington and Wyoming.

In Anne Arundel County there are more than 30 centers focusing on such specialties as podiatry, ophthalmology, obstetrics and plastic surgery, according to a provider directory of...