Tinnock v Murrumbidgee Local Health District (No 3)  NSWSC 88 is an interlocutory decision on admissibility of expert opinion evidence.
A plastic surgeon expressed opinions in a report about the use of drains in abdominal surgery, the phenomenon of prosthetic surgical-mesh infection, and the desirability of removing the mesh as a means of avoiding its deterioration to the very serious type of infection suffered by the plaintiff.
The plastic surgeon appears to have volunteered those opinions; they were not responsive to the questions put to him.
The court held at  that although the doctor’s expertise lies in plastic, rather than general, surgery, he is nonetheless a surgeon and that questions of the management of the risk of post-surgical infection are likely to be common across the various branches of the surgical profession. Accordingly it was held that he possessed relevant specialised knowledge.
The court went on to say at :
The third condition of admissibility is the need to demonstrate that the opinions expressed are in fact substantially based upon the expert’s specialised knowledge. I interpolate that the plurality judgment in the High Court in Dasreef (at ) points out that in the case of senior specialist medical practitioners the full rigours of what may be referred to as the Makita vSprowles  NSWCA 305; 52 NSWLR 705 (at 744 ) approach may not be applicable to expressions of opinion within the expert’s apparent field of specialisation. It may readily be apparent from the content and context of the report that the opinions expressed are in fact based upon, substantially, the expert’s specialised knowledge.