Medical Device Daily Washington Editor

WASHINGTON — Minimally invasive. “That's the buzzword,“ said Courtney Brown, MD, assistant clinical professor of orthopedic surgery at the University of Colorado Health Sciences Center (Denver) and an orthopedic surgeon at Panorama Orthopedics (Golden, Colorado).

Much of what is being presented at this week's annual meeting of the American Academy of Orthopaedic Surgeons (AAOS; Rosemont, Illinois) is focused on innovative treatments to get patients back on their feet sooner, with the least amount of intervention and pain.

Courtney, along with Paul McAfee, MD, orthopedic surgeon at the Scoliosis and Spine Center (Towson, Maryland) and Jeffrey Wang, chief of orthopedic spine service and associate professor of orthopedic and neurosurgery at UCLA Comprehensive Spine Center at the UCLA School of Medicine (Los Angeles), discussed emerging technologies in spinal surgery.

Overall, the standard of treatment for degenerative spinal disorders — such as slipped discs or compression fractures — is non-operative. Some patients, however, require surgical procedures that could include spinal fusion, injection of cement into the weakened vertebrae, or the placement of screws and metal plates to stabilize the spine.

Disc replacement — a procedure where the injured disc and replaced with an artificial one — has emerged as an alternative to fusion, offering some patients less post-operative pain, fewer complications and faster recovery, McAfee said.

McAfee participated in the trials focusing on replacement in the lumbar region using the Charité disc manufactured by the DePuy Spine (Raynham, Massachusetts) division of Johnson & Johnson (New Brunswick, New Jersey). Approved by the FDA last October, Charité is the first product cleared for this indication in the U.S. It has been approved for use in Europe for more then a decade.

The FDA cleared the disc for patients with degenerative disc disease in the lower spine who have had no pain relief despite at least six months of non-surgical treatment. DePuy has estimated that use of the Charité or any other artificial disc might replace from 15% to 35% of fusion procedures.

Other companies working on replacement disc technology — for the neck and back — include Medtronic (Minneapolis), Raymedica (Minneapolis), Stryker (Kalamazoo, Michigan) and Replication Medical (New Brunswick, New Jersey).

McAfee said FDA approval of another similar device is still “a little ways off.“

“The great thing about disc replacements is that they allow us to preserve motion in the patient's spine,“ he explained. He said spinal fusion immobilizes part of the spine, which in turn causes stress on the back and its range of motion.

“Also, if you need to fuse multiple vertebrae, recovery time and the chance of complications increase,“ he added. “With disc replacement, you don't have those problems.

McAfee said the procedure is not right for every patient, but called it “an excellent option“ if the clinical indications are followed. He said Charité trial data showed that replacement patients had an 82.5% increase in the flexion and range of motion two years after surgery compared to spinal fusion. He also reported reduced recovery time, in part due to the minimally invasive nature of the procedure compared to fusion, with some patients able to undergo the procedure on an outpatient basis. Around 87% of patients who worked were able to return to their jobs within six weeks of surgery.

DePuy, he said, had “taken the high road“ with an extensive program of surgeon training. The training program was part of the FDA's conditions for the Charité product approval (Medical Device Daily, June 4, 2004).

In addition to disc replacement, the panel identified other emerging treatments for back and spinal problems, including biological disc regeneration and computer-assisted and image-guidance technology such as surgical navigation where a surgeon uses an interoperative computed tomography (CT) scan to assist in the placement of screws and other devices when performing spinal fusion.

“Spinal fusion is still the best option for some patients, but studies show that in some cases, the screws are not ideally placed,“ Brown said. “Interoperative CT scans can help with placement of screws when the anatomy is difficult.“

He said the drawbacks of the procedure are that it is technically demanding and very expensive, with some systems costing upward of $500,000. Overall, Brown said this is a situation when “you have to spend money to save money.“

“We do believe we'll get better patient results, and it will reduce the time of complex surgeries,“ he said.

Companies with technology in this area include Medtronic Sofamor Danek (Memphis), Stryker and a new start-up, Breakaway Imaging (Littleton, Massachusetts).

Though much of the research into these emerging technologies is preliminary, according to Wang, they show “great promise.“

“Back injuries can be debilitating, so it's great to know that there may be even better ways for us to help those patients,“ he said. “However, we have to ensure that we don't circumvent the research process because everyone's excited about these new treatments.“

Also fitting this theme was a presentation on less- and minimally invasive surgery (L/MIS) for total joint replacement. According to panel members, these procedures have become highly requested procedures. Experts in the field discussed the pros and cons of the latest techniques, the need for more accurate measures to measure patient outcome, the best candidates for the procedure, and appropriate training for surgeons.

Current options for total joint replacement include using a six- to 10-inch incision, which cuts muscles to allow surgeons to clearly see and operate on the joint. MIS procedures use only a three- or four-inch incision. Other smaller incisions are required to insert surgical instruments.

“Minimally invasive surgery is a new, comprehensive approach to pain relief and rapid recovery that enables patients to walk independently and return home the same day after surgery, which is truly remarkable,“ said Richard Berger, MD, orthopedic surgeon at Rush University Medical Center (Chicago), one of the first surgeons to perform minimally invasive total hip and knee arthroplasty as outpatient procedures.

Alfred Tria Jr., MD, clinical professor of orthopedic surgery at St. Peter's University Hospital, Robert Wood Johnson Medical School (New Brunswick, New Jersey), said MIS is a better choice for knee surgery because it allows surgeons to spare cutting into quadriceps muscle.

Tria was involved in the design of a quadriceps-sparing technique for the knee, with which he says patients recover three times faster, have about a third less pain, 30% less blood loss, and 10 degrees more motion of the knee at the end of first and second years after surgery compared to standard procedures.

Pre-emptive analgesia and other anesthetic improvements, improved radiographic imaging, interoperative rehabilitation and patient education also have acted as major contributors to shorter hospital stays and reduction in recovery time, according to Thomas Thornhill, MD, chairman of the department of orthopedic surgery at Brigham and Women's Hospital (Boston).

“Surgeons will move toward using L/MIS techniques based on evidenced-based date published in peer-reviewed journals, not because of market demand for such surgeries,“ he said.

Incision size is not the more important aspect of the surgery, cautioned Thomas Vail, MD, director of adult reconstructive surgery and the Total Joint Replacement Center at Duke University (Durham, North Carolina).

“The procedure is a total package,“ he said. “You must focus on all aspects to ensure you get the best outcome from a combination of the right implant and tools, minimal tissue trauma, proper pain management, and the possibility of accelerated rehabilitation.“

Going “beyond all the hype,“ any new techniques must be critically examined as they relate to patient outcomes, said Anthony DiGioia III, MD, director for the Institute of Computer Assisted Orthopedic Surgery at the Western Pennsylvania Hospital (Pittsburgh).

“However, the goals are to develop new techniques that will permit more procedures to be done less invasively with improved accuracy and precision, but also safely and effectively,“ he added.