Dr. Greenwald has been practicing colon and rectal surgery at North Shore Hospital since 1991. He is Chief of Colon and Rectal Clinical Services at the hospital and has held many leadership positions including President of the Medical Staff and Chairman of the Medical Board. He has established protocols at North Shore Hospital (Enhanced Recovery) to ensure easy, safe, and rapid recovery after abdominal colon and rectal surgical procedures. Dr. Greenwald is dedicated to minimally invasive (laparoscopic) techniques for all types of colon and rectal surgery, including operations for diverticulitis, colon cancer, rectal cancer, Crohn s disease, Ulcerative Colitis, and rectal prolapse. He is particularly interested in sphincter sparing procedures so patients can continue to have natural bowel function. He performs diagnostic and therapeutic colonoscopies, and he is very experienced at both office and operative management of anal and rectal disorders such as hemorrhoids, fissures, fistulas, and anal incontinence. Dr. Greenwald is an Assistant Professor of Surgery at the Zucker School of Medicine at Hofstra/Northwell and has won multiple teaching awards.