The House of Lords in Chester v. Afshar [2004] UKHL 41, [2004] 3 W.L.R, 927, by a 3-2 majority, has upheld the Court of Appeal's decision, which extended the principles of causation in medical nondisclosure cases. The claimant, who had long suffered back pain, underwent spinal surgery by the defendant, a highly regarded neurosurgeon who negligently failed to inform her of a 1-2% risk of paralysis. The risk materialized and the issue was whether causation of damage could be established. This depended on what the claimant would have done had she been warned of the risk. If she would have avoided the procedure or sought alternative treatment, it could be argued that the failure to inform caused the claimant to be exposed to the risk and consequently the injury that resulted (cf. McAllister v. Lewisham and North Southwark Health Authority (1994) 5 Med. L. Rev. 343).