Can a party to a medical malpractice action be required to give an expert opinion on matters directly connected with the issues raised at trial?

In Shickele v. Rousseau, supra, a medical doctor was sued for damage for negligently administering anti-tetanus medication. On the issue of whether the discovery can be extended to matters of opinion even though relevant to the issue, Davey J.A. said at p. 570: [I]t is difficult to see why a party to an action that raises directly his professional or technical advice or conduct should not be required to give, on discovery, his expert opinion on matters directly connected with the issues raised, where that opinion would be admissible and relevant at the trial. Specifically, in this case, the appellant should be required to answer pertinent questions concerning his opinion upon the incidence of tetanus, proper anti-tetanus treatment, and the time it should be given, the recognized method of such treatment, the dangers involved therein, the safeguards to be adopted, general medical practice and opinion thereon, and like matters.