Wednesday, October 12, 2016

How does surgeon case volume relate to the complication rate?

Influence of Surgeon Volume on Inpatient Complications, Cost, and Length of Stay Following Total Ankle Arthroplasty.

These authors suggest that increased surgeon volume may be associated with improved outcomes following operative procedures.

They conducted a retrospective cohort study of total ankle arthroplasty (TAA) patients was performed using the Nationwide Inpatient Sample (NIS) from 2003 to 2009. High-volume surgeons were considered as those with volume ≥90th percentile of surgeons performing TAA.

A total of 4800 TAA patients were identified. The 90th percentile for surgeon volume was 21 cases per year. 

On multivariate analysis, high-volume surgeons had decreased overall complications (OR 0.5, P = .034) and rate of medial malleolus fracture (OR 0.1, P = .043), decreased length of stay (-0.9 days, P < .001), and decreased hospital charges (-$20 904, P < .001).

Comment: This study sets the 90th percentile as the standard for a 'high-volume surgeon'.

It stands to reason that surgeons in the top 10% of case volume will have (a) a robust basis on which to select patients that are likely to benefit from surgery (b) a wealth of experience with the varieties of pathology that might be encountered, (c) extensive technical experience enabling shorter surgical time and lower risk of complications, (d) an established preoperative team that can optimize the pre-, intra- and post-operative care, and (e) experience in recognizing and managing complications that might arise from surgery.

It also stands to reason that the most experienced surgeons are not immediately available to many patients needing surgery because of financial, insurance, geographical, family, and work considerations. 

In striking a balance between the benefits and the costs of pursing care from a high volume surgeon, it would be of interest to know if there is a 'tipping' point in case volume beyond which the benefit of increased volume diminishes or if the effect continues. The hypothetical graph below shows situation "A" in which higher surgical volume is associated with better quality care. It also shows situation "B" in which once a surgeon reaches a certain number of cases per year, the results do not change with additional increases in volume. 

Unfortunately we do not have these data for the surgeries we do. It seems likely, however, that the curve for most procedures would look something like situation "C" below, where the beneficial effect of increasing volume continues, but beyond a certain point the effect becomes less.

Yet, the more golf balls you hit, the better you get at hitting golf balls. 

Interesting commentary by one of our readers:

Gratifying to see that the clinical presumption of higher volume, better outcome is supported by the data. There is an ethical dilemma however when a patient is referred (for instance) to a rheumatologist by a low volume orthopedist who thereafter expects the patient to be returned to the surgeon when a procedure becomes necessary. What is the rheumatologist or primary care Doc to do? And how readily available are the data as to number of cases done?

Does low volume necessarily equate to poorer outcomes or are there low volume surgeons with outcomes just as good as the high volume surgeons? Patients are to be directed by increasingly forceful regulators to the high volume, better outcome surgeons?

And are there golfers of such intense natural skill that expert ability is achieved with far fewer balls hit? One fault in the analogy is that the golfer only has himself, the club, his shoulders and other minor joints and the usually stationary ball to deal with whilst the surgeon has himself, the patient, the anesthesiologist, the nursing staff, the family, the insurance company etc. to deal with.

A more app analogy would be the fly fisherman for whom practice increases the accuracy of the throw, development of the sixth sense of the targets location and the sensitivity and gentleness to successfully reel in the fish. All in the presence of weather, water currents and a moving, uncooperative target.

Thank you for your work with the blog. A continuing source of enjoyment and learning.

Our response: Who's to argue with the fourth paragraph?