373979
Dr. Michelson is the sole inventor of more than 250 United States patented instruments , operative procedures , and medical devices related to advances in spinal surgery or to the more general field of orthopedic surgery .
 Michelson
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Michelson