KB-2023-001134 - [2025] EWHC 2121 (KB)

Preliminary Issue 1(b): intraoperative skill and care

As noted above, the allegation of negligence in respect of the injury to the aorta was re-introduced by the Re-Amended Particulars of Claim for which permission was granted at the start of the trial. This amendment arose out of the more detailed explanation provided by Mr Nassar in his second witness statement of the technique he used to perform the sternotomy by way of response to points raised in the report of Mr Yap; permission was granted for service of the second witness statement at the start of the trial. The essence of the allegation is that Mr Nassar failed to grip the saw adequately, such that he lost control of it and/or that he used excessive force when cutting the anterior table of the sternum.

In his second witness statement Mr Nassar explained that he did not use the oscillating saw to saw through the sternum in one motion. Rather, his technique was firstly to open the skin and subcutaneous layer and then to place four sutures through the anterior table (i.e. the upper section) of the sternum (two stitches on each side) to allow the two surgical assistants to lift the sternum upwards. Mr Nassar explained that he then extends the incision into the muscle of the abdominal wall to create an access space underneath the sternum from which he dissects away any adhesions from the underside of the posterior table of the sternum (i.e. the surface closest to the cardiac structures). He then progresses upwards from the lower section of the sternum in five centimetre sections, cutting through only the anterior table of the sternal bone (i.e. leaving the bone marrow and the posterior section intact) whilst the assistants pull on the sternal stitches to lift the sternum away from the heart and aorta. Once the saw is through the upper table of the sternum, he uses scissors to cut the bone marrow and the lower table of the sternum, thereby leaving the five-centimetre section completely open. He then repeats the process for the next section until the whole sternum is opened.

Mr Nassar’s evidence was that the Claimant did not have any significant adhesions between the posterior table of the sternum and the aorta and that the aorta was not adherent to the sternum. As to the slipping of the saw, he said this in his witness statement:

“Unfortunately, however, the saw slipped whist I was going through a section of the anterior table of the sternum. It went straight through the bone marrow and the posterior table and caused the aortic injury”.

In his oral evidence, Mr Nassar emphasised that English was not his first language and, at times, he did struggle slightly in finding the most appropriate words to describe the details of events. He emphasised that he thinks that his description of the saw “slipping” may have caused confusion as what he meant was that he cut slightly more deeply than he had intended, rather than that he lost control of the saw.

In his third statement Mr Nassar further explained that using the oscillating saw is a “blind procedure in the sense that you cannot see through the sternum and so a surgeon must use their clinical experience and judgment to judge the depth that the saw has gone through. We do that by feeling for resistance” (original emphasis). He also explained that there will be varying levels of resistance in re-do surgery where you are going through an area which has healed following a previous sternotomy, meaning there can be different degrees of bone density. The fact that the saw slipped through the posterior table of sternum was, he explained, a recognised complication of re-do surgery.

The experts agreed that at any time in cardiac surgery there is always a risk of unintended entry into tissue, including by a saw in a re-sternotomy. Mr Yap said that this was complex surgery and that a reasonably competent surgeon who is qualified to perform such a procedure would be expected not to let the saw ‘slip’. Both agreed, however, that surgeons cannot entirely eliminate the risk of inadvertent damage when operating; it is a known and recognised risk.

Mr Elgot’s primary submission is that it is now apparent that Mr Nassar intended to saw through only the anterior table of the sternum and then to use scissors to cut through the bone marrow and posterior table. However, Mr Nassar did, in fact, cut through not only the anterior table but also the bone marrow and the posterior table and, further, any tissue plane and, further, the aortic wall. In essence, it is said that this evidences a significant loss of control of the cutting depth of the saw and was negligent. Mr Elgot’s submission was that piercing the aorta whilst attempting to cut through only the anterior table is not an inherent risk of a sternotomy and was negligent. The error arose because Mr Nassar let the saw slip and/or used too much pressure and, either way, he failed to control the instrument adequately. The Claimant contends that the court should infer negligence from these facts (res ipsa loquitur).

It is clear, in my view, that Mr Nassar misjudged the depth of the blade of his oscillating saw. This may well have been a momentary misjudgement and it may have been a misjudgement of a matter of a few millimetres. Such a misjudgement, in my view, falls squarely within the category of a risk of error which cannot be eliminated entirely even by the use of reasonable skill and care when performing a complex surgery involving a re-do sternotomy of this nature. It was a known and recognised risk of the re-do sternotomy. Indeed, it was the very existence of this known risk which required consideration to be given as to appropriate mitigating steps. It is very unfortunate and deeply regrettable that that risk eventuated, but the fact that it did eventuate was not, in my judgment, a result of negligence on the part of Mr Nassar in the manner in which he handled the oscillating saw.

Weight was placed by Mr Elgot on the delay in completing the operation note and on the fact that the operation note itself does not explain the mechanism of the injury. It is a matter of some concern that the operation note was not written up immediately after the surgery, but was only completed by Mr Nassar some 16 days later and did not then provide any information as to how the aorta came to be injured. This falls a long way short of the RCS guidance, quoted at [62.a] above, that operative notes should accompany the patient into recovery.

I appreciate that Mr Nassar was travelling abroad shortly after the surgery concluded to provide medical services for a charity. I have not seen the flight details, but in examination in chief Mr Nassar stated that he had to be at the airport at 04:00. Mr Nassar also says that he was present at the ICU handover, the record of which gives a “collection time” of 01:54. The operation note should clearly have been completed immediately after the surgery if at all possible. If Mr Nassar was entirely unable to complete the note, then he could have delegated that task to one of the other surgeons who was present for a significant part of the surgery, liaising with Mr Nassar as necessary.

It is also unfortunate, in my judgment, that the operation note was not more transparent about what had happened. The explanation that “Chest re-entry through redo-sternotomy was complicated by injury to the aorta causing catastrophic haemorrhage” does not begin to explain how the injury occurred. It is not clear from that note, for example, whether the injury was caused by the saw or during the course of attempting to dissect any adherence or any adhesions.

Nevertheless, insofar as it was suggested by Mr Elgot that I should draw adverse inferences from either the delay in producing the operation note or from the incomplete content of the note, I do not agree. There was an explanation, albeit not a complete explanation, for the delay in producing the operating note. Similarly, insofar as it was suggested that there was any deliberate attempt on the part of Mr Nassar or the Defendant Trust to conceal what had happened during surgery, I do not agree. The clarity of the other medical records on the fact that the injury was caused by the saw demonstrate that there was no attempt to disguise this fact: (a) Dr Leong, the anaesthetist, recorded in an anaesthetic intraoperative note timed at 13:36 BST on 3 May 2022, that “Saw accidently cut through the aorta causing massive haemorrhage”; (b) the ITU admission note (see [36] above) recorded the fact that the injury was caused by the saw; and (c) the physiotherapy initial assessment record of the following day, 4 May 2022, similarly states: “during sternotomy saw accidently cut through the aorta causing massive haemorrhage”.

Mr Elgot also takes the point that there is an apparent tension between the Defendant’s position that this incident was not a patient safety incident as the injury was a known complication of the re-do sternotomy and the fact that the incident was, ultimately, reported on Datix, but not until February 2023. The issue in relation to Datix reporting only appears to have been raised by the Claimant at the outset of the trial and was not pleaded. The Defendant’s evidence on Datix reporting was therefore limited and put together at speed during trial. I do not consider that it is appropriate for me to comment further on the Datix reporting issue in the circumstances. Again, insofar as it was suggested by Mr Elgot that I should draw adverse inferences from the delayed Datix reporting, I do not accept that it would be appropriate to do so.

In summary, in my judgment Mr Nassar was not negligent in respect of his control of the oscillating saw during the surgery and the intraoperative injury was not the result of any negligence on the part of Mr Nassar.