Variation in Surgical Volumes by Surgeons
A Case Study of the BAUS Audit on Prostatectomy
Recently, there has been ongoing debate around the impact of case volumes on surgical outcomes. A previous blog post (The Cost Debate in Robotic Surgery and the Impact of Skills) discussed a 2013 study published in the New England Journal of Medicine by Dr. John Birkmeyer, et al, which looked at skill levels between surgeons and identified that surgeons in the lower quartile completed three times fewer operations compared to surgeons in the top quartile.
In December 2012, the UK Government outlined plans to publish surgeon-level outcomes data, taken from national clinical audits, in ten specialty areas, which included Urology. This is known as the Consultant Outcomes Publication (COP) programme.
The British Association of Urological Surgeons (BAUS) has since published a number of audits on surgical outcomes in areas such as Prostatectomy, Nephrectomy, Stress Urinary Incontinence, and Urethroplasty. These audits are available for the general public to review the volumes and outcomes of a wide variety of surgeons.
The 2015 Prostatectomy audit, which looked at 2014 cases was published in September 2015 and the results are summarized below (as published on the BAUS website).
- The data collection period was from January 1, 2014 to December 31, 2014
- 6,161 cases were submitted in total, of which 5,814 were from England; these 5,814 cases came from 147 consultants at 62 sites, and include 230 private patients from 37 consultants
- Hospital Episode Statistics (HES) for 2014 indicate that there were 6,651 radical prostatectomies undertaken in England, so data was collected from 87% of the radical prostatectomies undertaken in England in 2014
- 5% were robotic assisted, 26.7% laparoscopic, 13.4% open and in 1.4% of cases the technique was not recorded
- Median number of cases per consultant: 32 (range 1 – 157)
- Median number of cases per center: 85 (range 1 – 250)
- The overall transfusion rate was 7% – for England only, 2.6%. In England only, the transfusion rates by technique were: open 5.4%, laparoscopic 0.8% and robotic 2.9%.
- 5,174 of the entries recorded whether there had been adverse events. The total post-operative complication rate was 5% (491 / 5174). Of these 491 cases, 364 recorded the Clavien Dindo grade (i.e. 127 or 26% did not). Complications classified as Clavien Dindo Grade III or above were seen in 1.6% of cases.
“Another interesting point to note was that there were differences in surgical positive margin rate between the three approaches,“ says Mr. Ben Challacombe MS FRCS (Urol) Consultant Urological Surgeon & Honorary Senior Lecturer, Guy’s Hospital & King’s College London. “Robotic surgery had an average of 13% while both the open and Laparoscopic approaches were at 19%. The length of stay was also seen to be lower for the robotic approach at a median of one day post operative”
We decided to go into each of the individual surgeons recorded on the web site and try and see if we could give any further insight into volumes carried out by the differing surgeons. Given that 12% of the cases do not have complications rate reported I did not try and see of there was a linkage between volume and complications due to the incompleteness of the data set available.
There were a number of interesting patterns.
Volume by procedural type:
As the table shows, more surgeons did Robotic cases and on average did more cases per year than the other approaches. We therefore decided to an analysis of the difference in procedures between the top and bottom quartile. A quartile was based on the number of surgeons doing the procedures so for example in the robotic cohort we compared the volume of the top 21 surgeons against the bottom 21 Surgeons.
The table below highlights the differences:
25% of the surgeons (37) with the highest volumes carried out over 50% of the cases. Interestingly the concentration was greatest in Open surgery where they carried out 69% of the cases. At the other end of the spectrum 37 surgeons with the lowest volumes only did just below 9 cases each or 5% of the total volume.
This picture is made slightly more complicated as clearly some surgeons will do more than one technique. In this sample 106 of the surgeons (73%) used only on technique while 36 used two techniques and three surgeons used all three techniques.
The overall surgical volumes increased as the number of techniques used increased. Those using one technique averaged 39 cases in the time period, those using 2 averaged 45 and those using 3 averaged 49 procedures. It is only natural that this occurs as surgeons move from one technique to another or believe that different patients are better suited to different techniques.
One of the big advantages of the 21st century is that data from surgical performance is becoming more transparent. This transparency is going to allow medical professionals to have visibility on a number of factors that affect patient outcomes, which will allow them to put in the correct protocols to ensure that the highest quality of care is always delivered. We believe that the increasing amount of data is showing that the use of validated simulation protocols and curriculum can ensure best results for patients.