A Portland, Ore., neurosurgeon who performed multiple spinal fusions on the same patients lost his operating privileges at the hospital where he did many of his surgeries and is under investigation by the Oregon Medical Board.

Providence Portland Medical Center revoked Vishal James Makker's surgical privileges last week following a March 29 article in The Wall Street Journal that identified Dr. Makker as having the highest rate of multiple spinal-fusion surgeries among 3,407 surgeons who performed the procedure on 20 or more...