The Ertl Procedure: Philosophy, Misconceptions, Realities

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The originators of the Ertl procedure advocated for a multidisciplinary, team approach.

The Ertl procedure originated in post-WWI Hungary, growing out of the need for a surgical reconstruction that would return injured patients to an active lifestyle and improve their physical fitness and psychological outlook. Professor Janos von Ertl, the surgeon general of Hungary at the time, developed the idea and philosophy, along with his sons John and William. And though the Ertl procedure has benefitted many patients over the past 80 years, many misconceptions about its application have arisen.

Biologic Surgery: A Foundational Philosophy

At the foundation of the Ertl procedure is the concept and philosophy of "biologic surgery," a philosophy we tend to apply to our surgical routine. By creating an optimal healing environment through remodeling, surgical reorganization, and reconstruction of the tissues, this philosophy draws on the body's regenerative powers, thereby limiting the surgical trauma of the approach. In effect, the surgeon directs the scalpel, which becomes an instrument of nature. At the inception, this philosophy was (and still is today) applied to multiple surgeries including spinal fusions, non-unions, craniofacial defects, general bony reconstruction, and amputation reconstruction, ultimately resulting in what we today understand to be the Ertl procedure.

Multidisciplinary treatment plan.

The Ertl Osteomyoplastic Amputation Procedure

Osteomyoplastic amputation procedure: Cross-sectional area and volume increased; provides decreased pressure per square inch.

The Ertl osteomyoplastic amputation reconstruction procedure is a combination of surgeries resulting in a well-contoured, functional, and dynamic limb that is prosthetically optimal allowing the patient to ambulate and function in a relatively effortless and painless manner. It incorporates an osteoplasty covering the end of the bone, sealing the medullary canal with a flexible bone graft (osteoperiosteal graft), and, in transtibial patients, creating a bony bridge that increases the surface area for potential end bearing. A myoplasty secures the antagonistic muscle groups, recreating a muscle-length tension relationship that can then mature, hypertrophy, and generate power, as well as balance the musculature around the bone and pad on its distal end. The arteries and veins are separately ligated, restricting arterio-venous (AV) connections. The nerves or neuromas are resected high, out of the surgical dissection field, and the skin is contoured to the underlying myoplasty, creating a smooth muscle/skin transition.

Misconceptions, Misapplications

Misconception #1: It's "Just about the Bony Bridge"

Misapplication of the osteomyoplastic technique.

Since its origin, many misconceptions, misapplications, and misunderstandings about the Ertl procedure have surfaced. The first misconception is that the Ertl procedure is "just about the bony bridge." This implies the only difference between this procedure and a conventional amputation is a block of bone placed between the tibia and fibula. In dealing with a transtibial amputation, the reality is that great care is given to creating a cannulated (tube like) intramedullary (IM) connection between the tibia and fibula. Additional bone graft may be placed within this reservoir, and in turn, the medullary canal to both bones is sealed. The medullary canal is also sealed in single-bone extremities, transhumeral and transfemoral amputations. By sealing the medullary canal, an IM pressure is recreated and peripheral circulation is improved.

Misconception #2: "Speed Is of the Essence"

The second misconception is that "speed is of the essence" and that the prosthetist can correct any problems, imperfections, or shortcomings. Amputation surgery should be viewed as a reconstructive procedure, similar to a joint reconstruction or breast reconstruction. At their foundations, these types of surgeries are amputations as well—the internal amputation of a hip or knee joint with subsequent reconstruction, or a mastectomy, breast amputation with subsequent reconstruction. Time, care, and attention are given to these types of surgeries. And yet they are still amputations with the intent of restoring function and aesthetics.

The central goal of amputation reconstruction is achieving a functional residual limb that is prosthetically optimal, remembering that the patient is the foundation upon which success will ultimately be based. A multidisciplinary approach is required in achieving these goals with the input and treatment of prosthetists, nurses, physical therapists, social workers, patients, and physicians.

Misconception #3: "Intramedullary Closure Doesn't Matter"

The third miconception about the Ertl procedure is that "intramedullary closure doesn't matter because the bone scars in." Although this probably occurs, it would not occur until the advantages of IM closure are lost. When the medullary canal is left open, AV connections can occur, leading to a high output type malformation, as the venous gradient drops to 0mmHg leading to venous stasis. Bone spurs may form around the end of bones, and with a lack of bone loading, regional osteopenia occurs, as well as progressive periarticular osteolysis and subsequent degenerative joint disease. Osseous reconstruction or osteoplasty removes residual bone scarring in secondary amputations, closes the IM canal and reestablishes IM pressure, allows for end bearing, and at the transtibial level, creates a synostosis (bridge), thereby stabilizing the fibula from lateral deviation and giving a broader platform for end bearing.

Misconception #4: "Just Close the Wound"

End bearing. Axial alignment of prosthesis; no flexion needed. Diabetic patient with long residual limb.

When the musculature is transected, it retracts, resulting in fatty degeneration and atrophy, venous stasis, slower contraction speed, persistent extremity volume changes, poor distal soft-tissue coverage, and a lack of soft-tissue stabilization, which leads to soft-tissue imbalance and instability. By performing an antagonistic myoplasty, these problems can be negated and an improved physiologic environment can be created. A length-tension relationship is reestablished within the musculature allowing for greater force generation and the opportunity for muscle hypertrophy from its current state and a greater surface area for prosthetic management. There is an improved vascularity to the soft tissues by decreasing the AV connections and reestablishing venous return from the contraction of the muscles. Additionally, EMG studies have shown a more rhythmic contraction cycle in walking and greater efficiency of muscle use with stabilized musculature.

The application and construction of the osteomyoplasty helps to combat the effects of inactive residual extremity syndrome (IRES) and inactive extremity syndrome (IES). These syndromes are the result of tissue disorganization and cause pain, swelling, a sense of instability, prosthetic difficulties, bone and soft-tissue atrophy, and fibular instability, all of which lead to extremity inactivity. Because of its biologic and physiologic approach, the Ertl procedure addresses these symptoms through a combination of reconstructive surgical procedures.

Misconception #5: "10cm of Distal Residual Bone Is Sacrificed"

Axial loading and limb desensitization provides mechanical stimulus for bone regeneration.

A fifth misconception deals with the amount of bone removal in a secondary transtibial amputation, specifically that "10cm of distal residual bone is sacrificed." It is unclear where this statement originated; however, it has been perpetuated without credibility or responsibility. The reality is that the level of amputation will be determined by patient goals, clinical exam, x-rays, and vascular studies. We choose not to apply a static length to all amputations. Taller or shorter stature patients cannot be treated in a conventional manner or with a static length and most often require custom length determination. Although we do prefer as long an extremity lever arm as possible and the maintenance of length is important, these factors are not so important that we would compromise prosthetic application or fit. Even with secondary amputation reconstructions, minimal bone is resected and bone or osteoperiosteal tissue can be harvested from multiple alternative areas.

Misconception #6: The Ertl Procedure Should Not Be Performed on Patients with Diabetes

Following an appropriate clinical work-up and evaluation and with the factors discussed above, the diabetic population would notably benefit from the Ertl procedure. The possibility of improved bone and soft-tissue perfusion could allow these patients to maintain active lifestyles, thereby adding to their longevity and potentially decreasing their medication dosages.

Misconception #7: The Ertl Procedure Cannot Be Performed on the Pediatric Population

When considering the pediatric population, the concern is that capping the terminal bone will prevent enchondral bone growth, as well as proximal fibula overgrowth. In our experience, we have seen two cases of terminal overgrowth that were easily corrected with an additional procedure. The benefits of the surgery have been maintained.

Misconception #8: Misapplications

The Ertl procedure for amputations can be applied to upper-limb patients and lower-limb patients alike.

The eighth misconception involves the misapplications of the procedure. Many believe that the procedure is "just about the bridge," "is only applied to the transtibial level," or that it is done to "just get a synostosis." The Ertl procedure for amputations has been applied at the transfemoral, transmetatarsal, transhumeral, transradial, and transdigital levels. As described above, the Ertl procedure is the application of osseous and soft-tissue reconstructions in attempts to achieve the optimal residual limb. The end results of these procedures cannot be compared to the original description when the surgery is performed incorrectly, incompletely, or inconsistently.

Misconception #9: The Available Literature Reports Negative Results

The final misconception regards the available literature. The largest study to date was presented at the 1997 American Academy of Orthopaedic Surgeons (AAOS) meeting. Data was gathered over a 15-year period, and results were reported for both transtibial and transfemoral levels. Overall results demonstrated a good outcome for 92 percent of the transtibial population studied, and an excellent outcome for 90 percent of the transfemoral population studied. Additional articles have been published with positive and improved results over the accepted or conventional amputation procedure.

When correctly applied, the Ertl procedure is a reconstructive surgery that provides the amputee with a physiologically sound residual limb capable of increased function and end bearing. Over time, patients have high subjective and good objective satisfaction with improved outcomes over a conventional amputation procedure. This procedure can be applied to the vasculopath, diabetic, and pediatric patient populations. On average, minimal bone is resected and length is maintained. The Ertl procedure can be performed at multiple amputation levels as both a primary and/or secondary reconstruction surgery.

While it is preferable to get as long an extremity lever arm as possible, a static length is not applied to amputations using the Ertl procedure.

An amputation is not a benign or static procedure. The residual limb is active and dynamic, as should be the team engaged in caring for the amputee. The Ertl procedure should be viewed as a reconstructive surgery, and the effort must be placed on a team approach. The goal is to return to the patient a functional residual limb, which is accomplished by adhering to "biological" surgery principles.

The Ertl procedure is the result of an idea, thought process, and philosophy based on reconstruction of an amputated limb to as near a normal biologic and physiologic state as is possible. Procedures have been completed and incorrectly labeled as the Ertl procedure when the above misconceptions are applied. This, in turn, results in reports of poor outcomes and discredit is erroneously bestowed upon a procedure designed to improve the lives of the amputee population.

Jan Ertl, MD, is an associate professor at the School of Medicine, Department of Orthopedic Surgery, at the University of Indiana, Indianapolis. He specializes in trauma care and limb amputation. William Ertl, MD, is an assistant professor in the College of Medicine, Department of Orthopedic Surgery and Rehabilitation, at the University of Oklahoma Health Science Center, Oklahoma City, Oklahoma. Christian Ertl, MD, FACS, is a community surgeon and clinical instructor in the Department of Surgery at the University of Connecticut, Bristol. He specializes in general surgery, including limb amputation.

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