Anthony Romeo, MD, director of the section of shoulder and elbow at Rush University Medical Center in Chicago, has spent the past several years developing the technique, instrumentation and implants for a minimally invasive total shoulder replacement. This past summer, he performed the procedure for the first time in a patient. The procedure was successful and is on the verge of becoming a big change in shoulder surgery. "I think this procedure will have a tremendous ability to impact patients, particularly our active patients with shoulder arthritis, because it will allow us to do the operation with minimal damage to the rotator cuff," says Dr. Romeo. "By avoiding injury to the largest muscle of the rotator cuff, the subscapularis, our patients with arthritis will have a better chance of returning to full activity, whether related to work or sports."Here, Dr. Romeo discusses his process for developing the procedure and where he sees it heading in the future.
Q: What was your motivation for developing this technique for minimally invasive shoulder replacements?
Dr. Anthony Romeo: I was motivated by the fact that one of the most challenging problem with regards to return to function after a shoulder replacement has been how well the rotator cuff tendon heals after surgery. To perform a shoulder replacement in the standard fashion, we go through the front of the shoulder and the subscapularis. Any time you cut the tendon or move it out of the way, up to 20 percent of patients will have a change in function because the muscle undergoes permanent atrophy.
What we have been doing for more than 50 years is creating a rotator cuff tear to access the arthritis in the patient's shoulder and then repairing that rotator cuff tear afterward. One out of every five patients has a problem with the rotator cuff returning to its normal size and function. There has been a lot of research about different ways to move the tendon out of the way, including an osteotomy and lifting the bone with the tendon to prevent this problem. There is some evidence to suggest it may be a little bit better with that technique, but it's still a major problem.
It was my plan to do this operation without cutting the rotator cuff at all. That would dramatically change the results of shoulder pain for arthritis.
Q: What elements of this new procedure make it innovative?
AR: I wanted to figure out a way to perform the shoulder replacement consistently through the rotator interval — not through the tendon. I wanted to go through the small hole of the rotator interval, remove the humeral head — which could be 50 mm or more in diameter — and be able to replace the glenoid and humeral head without removing any attachment in the rotator cuff. I wanted to make the procedure reliable and consistent, which requires guides and instruments specifically designed for this approach.
Based on the restriction of the size of the rotator interval, I worked with talented engineers and developed a technique where the neck-shaft angle for the humeral head is identified with a special guide and then a large pin is placed from the lateral side of the humerus into the center of the humeral head. The tip of the strong pin comes out of the center of the humeral head and then connects to a bone reamer, which can be placed inside the joint. When you pull back on the pin, the reamer cuts away the humeral head — you retro-ream the humeral head. It has a tissue protector so it stops before it cuts into the rotator cuff.
Q: How long did it take you to develop this procedure?
AR: It took about two years to develop and confirm the methods that are used to identify the proper position of the alignment guides, which are used for the placement of the reaming device. Once the humeral head is correctly resected, there is enough room to release the capsule and then work on both the humerus and glenoid preparation. There have been many developmental cadaver labs as we went through the prototypes and tested the methods, refining the technique each step of the way before we proceeded to perform the operation on patients. We had to make sure it was "do-able," and once we knew it was possible, we had to make it as safe as possible for our patients.
Another important priority was to design the technique so that other surgeons could adapt it into their practice and make it safe for their patients too. That's a complex set of events to arrive in this place.
Q: Are there any other surgeons who are doing this procedure, or have done anything like it in the past? How does it fit with the evolution of surgical technique for shoulder surgery?
AR: Yes, Laurent Lafosse from Annecy, France, has been a pioneer in rotator-cuff preserving shoulder replacements. He published a case series regarding his method of a "free-hand" cut of the humeral bone through the small window of the rotator interval. You can imagine the challenges and potential risks that are inherent in that technique, especially when less experienced surgeons try this method. Therefore, a major focus of the innovation was developing guides and instruments that would allow surgeons to accomplish this procedure accurately and safely.
It's important to ensure that the overall care of the patient is not compromised by an inability to get the replacement in the correct position, or by an increased risk of complications. The development of a reverse reamer or "retro-reamer" has never been described as a technique to be used for shoulder replacement surgery.
We went through many cadaver procedures before performing the operation on my first patient. Our initial patients have done exceptionally well and they were sent home the day after surgery. In the future, if implant reimbursement is aligned with this technique, and a multimodal anesthesia approach is used, this could be an outpatient procedure for many of these patients. Patients require less narcotic medication, and therefore have less nausea and drowsiness; they are up out of bed the day of surgery, and easily transition from the preoperative interscalene block to oral pain medications.
Q: Do you see this procedure becoming more prevalent in the future?
AR: Yes, the technique will become more widespread, but there will be limitations when the severity of arthritis results in large osteophytes and deformities of the glenoid. Over time, these challenges will inspire additional innovation that may help to reduce those patients who are not good candidates today. I don't think this technology will be useful for most revision surgeries. However, the technology and technique can be used for an operation that has become much more common: reverse shoulder replacement. I predict that up to one-third of shoulder replacement cases could use this new technology.
Q: How much training is involved for surgeons to incorporate this procedure into their practices safely?
AR: Surgeons will have to understand that there is a significant change in surgical exposure and the releases around the shoulder joint that must be performed through the rotator interval. These releases are essential to the operation, and they are more technically demanding when the rotator cuff is intact. Surgeons are going to have to learn how to do these releases to make sure they put the guides and reamers in the right spot and give themselves full exposure to the glenoid for glenoid replacement.
Certainly, it will be important to undergo a surgeon-training program and practice this technique in a cadaver lab situation so they feel comfortable with the surgical exposure and the use of new instruments.
Q: Since this procedure is so new, are surgeons able to bill for it and receive appropriate reimbursement?
AR: The implants that are used through the rotator cuff are the same as the standard shoulder replacement, but the technique has changed substantially. This is something that needs to be worked out with insurance companies. The new procedure would be considered "unlisted" in terms of billing.
Q: Where do you see the field of shoulder surgery evolving in the future?
AR: Shoulder replacement surgery has advanced substantially over the past 10 years. The implants are more anatomic and provide an opportunity for better shoulder function. Currently we are seeing many centers working on the challenges of the glenoid, and I anticipate we will have more options for patients with severe glenoid alignment problems and bone loss.
However, the function of the shoulder remains heavily dependent on a healthy and strong rotator cuff. Cutting through the rotator cuff creates damage to the shoulder that was not present before the operation, and we have to adjust the postoperative care and rehabilitation based on this surgeon-imparted injury. If we can consistently perform the operation without cutting through the rotator cuff, patients are more likely to achieve their maximum potential in terms of pain release, range of motion and function.
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