Expert evidence
163The appellant's submissions placed much reliance upon the evidence of the expert doctors, in particular, that given during the course of the concurrent evidence (see [55] to [63] above).
164The appellant's submissions acknowledged that the question of breach of duty is a matter for the Court, which is not bound by the opinion of the experts. It was submitted however that in the circumstances of this case the expert evidence should have had an influential, indeed a decisive role to play on the question of breach. See Rogers v Whitaker [1992] HCA 58; (1992) 175 CLR 479 at 487; Rosenberg v Percival [2001] HCA 18; (2001) 205 CLR 434 at 454.
165As explained above (at [162]), the factual inquiry concerning the technical performance of the laparoscopic cholecystectomy by the appellant involved a consideration of whether the deployment of the diathermy current at or near the surgical clips as found by the trial judge, was avoidable by the exercise of reasonable care or was something less, being an unavoidable risk of the procedure. The inquiry did not involve expert opinions as to the appropriate clinical judgment concerning how close to the clips the surgeon should use the diathermy current. The appellant and Dr Drew were agreed that the diathermy current should not be deployed near the surgical clips, though Dr Hugh did not specifically address this issue. The inquiry, in this case, was somewhat more stark than the general evidence given by the experts concerning the possibility of bile duct injuries during a laparoscopic cholecystectomy, including diathermy injury. The inquiry was whether the deployment of the diathermy current such that it came into contact, or in very close vicinity of the clip, was an error which was avoidable by the exercise of reasonable care.
166In my view, the trial judge was entitled to reject the expert evidence on the ultimate issue and reach his own conclusion on the question of breach of duty of care. My reasons are as follows.
167First, the evidence of Dr Hugh in his report of 26 July 2011, that bile duct injury and stricture formation may happen to the most careful surgeon was expressed in only general terms by reference to a variety of possible causes of such injuries, only one of which included the use of diathermy instruments. Dr Hugh's report did not address the specific mechanism of the diathermy injury in the present case, as found by the trial judge. This is not surprising as Dr Hugh did not consider that any injury occurred during the operation on the respondent.
168Secondly, insofar as Dr Hugh pointed to the widely expressed view in the medical literature that the risk of bile duct injury and stricture formation may happen to the most careful surgeon when the operation is being conducted with all due care, the chief focus of this literature was misperception errors by the surgeon concerning the patient's anatomy, which included injuries resulting from a dissection too close to the common hepatic duct. This literature is of little assistance in the present case, because the appellant's usual technique did not involve dissection (by use of the diathermy) in the location of the cystic duct or the common hepatic duct, and there is no suggestion by the appellant of any misperception issue when carrying out the procedure.
169Further, the medical literature tendered at the hearing did not address the specific issues of either the use or unpredictability of the diathermy current in laparoscopic procedures, or injuries to the common hepatic duct resulting from current transmitted through the clips attached to the cystic duct. The class II type injuries (consisting of lateral damage to the common hepatic duct that produced a stricture and/or fistula formation) referred to the article by Dr Way and others (published in the Annals of Surgery in April 2003), were described as follows:
"These injuries usually involve the placement of clips on the duct in conjunction with cautery damage during attempts to control bleeding (23%) or as a result of poor exposure (68%). Class II injuries never completely transected or occluded the CHD; they involved severe lateral damage leading to stricture formation (with or without a bile leak)."
In the present case the respondent's injury was not a consequence of the incorrect placement of the clips on the common hepatic duct leading to bleeding which the appellant attempted to control by cauterization, nor poor exposure, that is, difficulty in identifying the respondent's ductal anatomy before dissecting the cystic duct from the gallbladder.
170Later the same article explained that:
"In the class II ...injuries, the mistake consisted of performing the dissection in the triangle of Calot unintentionally too close to the bordering common hepatic or right hepatic duct. The ducts were not seen because they were covered by connective tissue or inflammation. The underlying nature of the error in either case was misperception."
It will be observed however, that the appellant's usual technique for this procedure was developed to avoid the type of misperception problem referred to by these authors, when performing the dissection of the gallbladder off the liver.
171For the same reason, the conclusion expressed by Way and others that:
"... the usual misperception error underlying laparoscopic bile duct injuries does not meet the defining criteria of medical negligence",
has no application to the present case. It is not suggested by the appellant that there was any misperception of the respondent's ductal anatomy resulting in a dissection of the cystic duct too close to the common hepatic duct. Moreover, the dissection of the cystic duct, according to the appellant, did not involve the use of the diathermy instrument. A different cutting instrument was used by the appellant.
172Thirdly, Dr Hugh's oral evidence went no higher than that he did not agree that the respondent's injury "must" have been caused by a want of skill and care by the surgeon. As the trial judge correctly observed, Dr Hugh's oral evidence was in very general terms. His evidence did not address the usual technique followed by the appellant when performing laparoscopic cholecystectomies, in particular, that the diathermy current was not deployed in the location of the clips attached to the cystic duct or the common hepatic duct.
173Fourthly, Dr Drew's agreement with the cross-examiner's proposition that it was well known in the medical literature and by the experience of surgeons that even the best of surgeons using the best technique are subject to the risk of a diathermy burn in this particular type of surgery, was also given in only very general terms.
174Fifthly, Dr Drew's evidence concerning the unpredictability of diathermy, is not to be taken as evidence that the particular injury in this case was unavoidable. This is because the mechanism of the respondent's injury, as found by the trial judge, did not depend on the unpredictability of the diathermy current, but rather the deployment of the diathermy in the location which the appellant conceded would have been the "wrong position", and which the appellant knew must be avoided to avoid the possibility of conduction of current through the clips to the bile duct.
175Sixthly, the trial judge was entitled to find on the appellant's evidence that a bile duct injury caused by the diathermy current coming in contact with, or close vicinity to, the clip, was not a normal risk of surgery. The appellant's failure to include such risk as a normal risk of surgery is an implicit acknowledgment that the injury in this case was avoidable.