How many bunionectomies do you perform each year? How many toenail matricectomies per week? How about biomechanical exams and orthotic impressions? Should patients undergo surgery by you if your volumes are below a certain number? Am I a good surgeon if I don't perform thousands of a particular procedure? What about new physicians? Our podiatric residents are constantly on the search for more cases, assuming volume is important to training. What about variety? Volume may be a simple empirical way to determine a doctor's proficiency and chance of successful outcomes, but is it the most appropriate way? Does volume matter? Let's examine the literature to see if the evidence gives us an a convincing answer.

Volumes and Mortality

This is a somewhat controversial subject with a history. In a seminal article in 1979, Luft, et al. examined the mortality rates of different surgical procedures based on volumes performed. They found for several procedures (cardiac, vascular, and transurethral prostate resection surgeries) the mortality decreased with increasing surgical procedures (25-41% lower than hospitals with lower volumes).¹ Other procedures, such as cholecystectomy, did not follow this trend. This study sparked years of discussion, research, and even lent scientific credence to the idea of a "center of excellence," implying higher volume among other things which is becoming increasingly common.

Over the years, the volume argument has been made throughout the literature with disputed results. The arguments have also been waged in residency committees and hospital credentialing boards, among others. A more recent study re-examined the mortality rates for several different cardiovascular procedures and reported some interesting findings.² Although the same trend of higher volumes leading to lower mortality was seen, the significance of this difference varied based on the specific procedure. For example, the researchers found a 12% difference (higher volume vs. low volume hospitals) with pancreatic resection but only a 2% difference when it came to CABG and lower extremity bypass among others.

The one common factor between these two studies was their focus on mortality. Volume may be important for high risk procedures, but what about less risky procedures? What about podiatry? The majority of reconstructive podiatric procedures are not oriented towards mortality but rather morbidity reduction. With that being the case, does volume matter in podiatric surgery? Does it matter what type of procedure is performed? What does the literature say?

The Orthopedic Literature

Since my search of Pubmed did not find any studies oriented to foot and ankle surgery, let's focus on the next best thing: orthopedic procedures. Katz, et al. examined the complication rates of total knee replacements (TKR) in a cohort of Medicare patients and found higher rates of complications (mortality, infection, PE, MI, or pneumonia) with hospitals and surgeons who performed lower numbers of these procedures. ³ Of note, surgeons who performed more than 50 TKRs/year were the higher volume surgeons (vs. 12/year for the lower volume ones) while the original Luft study used 200 procedures/year as the higher volume number.

A similar study was recently performed in Ontario, Canada, studying complication rates in total knee replacement (TKR) and total hip replacement (THR). ⁴ This study, which included 20,290 THAs and 27,217 TKRs, found length of hospital stay and revision rates for THR (but not TKR) were lower with higher volume surgeons. No associations were found with volume and mortality. Contradictory studies certainly.

The Questions Remain

These studies bring out the obvious question, what number of procedures is the threshold for high volume? This is a more complicated question than one might think, the answer of which is affected by the complexity of the procedure and prevalence of the treated disorder, among other factors. For example, I might argue that performing a matricectomy is less complex than an Austin bunionectomy, thereby allowing lower volumes without seeing significant complications (in addition to the fact that the complications from a bunionectomy are more complex than for a matricectomy). I'd argue that this threshold number varies based primarily on these two factors (procedure and pathology complexity and pathology prevalence).

So, does volume matter in podiatry? After my cursory review of the literature…I'm not sure. I know, after all, that my answer is not so satisfying. Here are my conclusions to date about volume.

There's likely a direct correlation between the complexity of a procedure or pathology and the success with higher surgeon and hospital volumes. The more complex the procedure, the more you need to do to attain proficiency.

Volume plays an important role in high risk surgical procedures with an already high level of morbidity and mortality. These procedures should probably be regionalized to centers of excellence where high volumes can be sustained.

One can extrapolate from #2 that podiatry's highest risk subspecialty, limb preservation, would be most successfully undertaken at regionalized sites.

This might also be true for certain high complexity reconstructive procedures such as symptomatic flatfoot or cavus foot reconstruction, but likely to a lesser degree.

A certain (unknown) threshold of volume is probably necessary for resident and fellowship training, but variety may be as important, and there may be a volume limit (also unknown). Is there a volume in resident training where we hit the law of diminishing returns?

More research is necessary, in both medicine as a whole and podiatry as a specialty, to answer this complicated question. Podiatry research would need to focus on other markers such as infection rates, amputation rates in limb salvage, OR time, revision rates, recurrence, etc.

The answer to the volume question will likely require input from the fields of surgery, educational theory, and medical administration, among others. Until more work is done, we'll never truly know the answer. The current reality is, when a patient asks her surgeon about experience, she's really asking how many of the planned procedure has the surgeon performed. Our patients do not understand the complexity of the question, and unfortunately, we can't educate them well using the current evidence. Will there be a time in the future where all surgeons must publish the number of each procedure they perform? Only time (and, hopefully, further research) will tell. Without a solid understanding of all these factors, I can only guess how detrimental this could be to the medical community.

What do you think?

Keep writing in with your thoughts and comments. Better yet, post them in the eTalk forum, where you can get in on the discussion or start one of your own. Best wishes.

Jarrod Shapiro, DPM
PRESENT Practice Perfect Editor
[email protected]

References

1. Luft, et al. New England Journal of Medicine, Dec 1979; 301: 1364-1369.
2. Birkmeyer, et al. New England Journal of Medicine, Apr 2002; 346(15): 1128-1137.
3. Katz, et al. JBJS, Sept 2004; 86A(9): 1909- 1916.
4. Paterson, et al. Canadian Journal of Surgery, June 2010; 53(3): 175-183.
   

	The Diabetic Charcot Foot: Principles and Management by Robert G. Frykberg DPM, MPH, Editor
	This text provides the reader with the most current information available on the pathogenesis, natural history, and management of the diabetic Charcot foot. Many of the world's experts have come together to present their unique perspectives on this disorder. It is our hope that this work can become a valuable resource for those less familiar with the peculiarities of this often misunderstood complication of peripheral neuropathy. I am indebted to each author for the contribution of their time, efforts and expertise.
	Follow this link to learn more and order your copy today.

Sign up today and receive up to $60 Credit for CME

Major Sponsors