The Ertl Controversy: Where Do We Go From Here?
Previous Corners have tried to summarize some of the major points of discussion regarding the Ertl amputation procedures and reviewed the preliminary objective evidence available on this concept. This article concludes this series of commentaries with seven suggestions for furthering the interest in this method.
- Continue the Discussion and Debate
One of the greatest contributions of the Ertl debate has been the focus on tailoring the residual limb for maximum effectiveness at controlling an artificial limb. Even if some of the specific claims for this particular approach cannot be validated, the concept of creating a "prosthesis controller" rather than performing the amputation as an isolated procedure is an import philosophical contribution. At least in today's U.S. Managed Care environment, surgery and rehabilitation care are often provided in relative isolation from one another.
Although technological advances enable the prosthetist to effectively fit a larger percentage of sub-optimal residual limbs than was possible in earlier decades, we cannot fully overcome the limitations of a painful or fragile residuum. When combined with a painless, stable, and strong residual limb, modern technology is far more effective at permitting a normal lifestyle. So, optimal surgery complements and amplifies the effectiveness of optimal prosthetic rehabilitation.
- Take Names
It is very important to keep contact with patients who have undergone Ertl procedures long term, particularly those with more recent amputations. As the numbers grow, a critical mass will develop that should be sufficient to demonstrate not only clinically significant advantages but also statistically significant results that are difficult to dismiss. So, maintaining an "Ertl registry" may be a very important contribution to ultimately resolving the present debate.
Ideally, everyone who underwent an Ertl procedure should be included so we can get a more accurate assessment of the relative risks in addition to the benefits. If the only subjects available for study are vocal advocates for the method who had a good personal experience, then the sample is biased and the results will be questioned.
- Think Syme
Biomechanically, the idealized Ertl transtibial residual limb is much like a "mini-Syme" amputation: a predominantly end-bearing organ with intact musculature, stable skeletal structures, and mobile, sensate skin coverage. Unlike the Ertl, the Syme residual limb has been objectively studied by a number of researchers, and several biomechanical advantages have been documented.
For example, there is a general trend demonstrating less effort required to walk a given distance in a prosthesis with an end-bearing Syme amputation compared to a transtibial ablation. It seems likely that a successful Ertl transtibial procedure would demonstrate a similar increase in energy efficiency, particularly if fitted with a predominantly end-bearing socket design as advocated by Stokosa and others. This protocol is well established and could be readily measured by many instrumented gait laboratories in the US and elsewhere.
There must be many other advantages that could be gleaned from the Syme literature and then investigated in the Ertl population.
- Define the Outcomes
This sounds easy but is actually very challenging. The usual testimonials on the order of, "It had a good beat and I could dance to it so I gave it a 10" will not suffice. The proponents could work together to define objectively measurable surgical outcomes, prosthetic outcomes, and quality of life outcomes they believe the Ertl offers. This would drive objective research and focus the debate on factors that are likely to result in more widespread acceptance of the method in the long run.
- Gather Pilot Data
Every good clinical study starts with a good hunch based on clinical observation. There is substantial enthusiasm in the prosthetic and amputee communities for the Ertl protocol, so the hunches are already present. The next step is to define outcomes that are accurately measurable and then to study a small group of amputees to see if the initial data supports the hypothesis that the Ertl is better.
Pilot studies are usually self-funded, limited in scope, and often include just a handful of subjects. This could be undertaken by almost any center performing this operation, and encouraging results would generate further interest and likely funding for a larger, more definitive investigation.
- Seek Research Funding
Achieving #5 is the key to accomplishing #6. Good pilot data combined with a well-written proposal can be submitted to funding agencies such as the Veteran's Administration or the National Institutes for Health, who already fund prosthetic and orthotic research. In my experience, both these agencies are interested in good P&O clinical studies and provide long term funding to answer important rehabilitation questions. There may be other potential funding sources as well.
- Publish in Peer-Reviewed Journals
As discussed previously, the dearth of peer-reviewed articles on the Ertl is a major impediment to more widespread acceptance. Hopefully, #s 4-6 will provide the evidence necessary to withstand peer review and result in widely disseminated publications on the method. In my view, this is the best mechanism to substantially increase the number of Ertl procedures performed, and that will increase the number of potential research subjects making it easier to conduct more definitive research.
Anecdotal reports in trade magazines are not peer reviewed and therefore do not address this shortcoming. Case presentations in peer journals are a first step, but to be really effective the goal must be to gather and publish replicable studies that generate objective data.
