A Conversation with Professor Jean Dubousset

Did you know that until fairly recently, spine surgery for the treatment of scoliosis—a condition in which the spine develops one or more abnormal, side-to-side curves—often required a patient to spend months, in some cases even a year or more, encased in plaster casting and strapped into a brace or frame? Because of the way spinal curve correction was addressed, the extended immobilization and strategically applied pressure the casting, bracing and frames supplied were integral to the postoperative recovery process.

This year, we celebrate major milestones for two Medtronic technologies developed as part of a revolution that has taken place over the past several decades to improve both spinal correction and the recovery process for patients: the 25th anniversary of CD® Instrumentation and the 20th anniversary of the TSRH® Spinal System.

Professor Jean Dubousset and I
discuss the history of scoliosis treatment.

To kick off our celebration, today I'd like to introduce you to one of the medical researchers who played an important role in this "spinal revolution" and who helped develop the technology on which these systems are based. Professor Jean Dubousset, professor of pediatric orthopaedics at the University Rene Descartes in Paris, was the first surgeon to operate on a patient with spinal curvature using prototypes of a new kind of instrumentation designed by another orthopaedic pioneer, Dr. Yves Cotrel. The surgery took place in 1983; the exciting outcome of the procedure was that the patient was able to stand and walk without a cast or brace only several days after surgery. Dr. Cotrel, formerly with the renowned French hospital Institute Calot, had been working to improve the lives and treatment outcomes of scoliosis patients since 1948 when, just out of medical school, he arrived at the Institut Calot and was shocked to see the bulky, uncomfortable casts and other "primitive-seeming" contraptions young scoliosis patients were subject to, often with only temporary success.

Today's blog entry is the first in a two-part series with Prof. Dubousset. Before we get to our conversation with Prof. Dubousset, however, I'd like to give you a little background on scoliosis, and an explanation of how and why the design of this instrumentation led to such a successful outcome and paved the way for the innovative technology that allows surgeons to continue to improve the lives of their scoliosis patients today.

Scoliosis curve
before spine surgery

Scoliosis is a condition in which the spine develops one or more abnormal, side-to-side curves that in turn may affect the body's overall balance and alignment, as well as possibly lead to other physical and health problems. Now, a certain degree of curvature is normal in the human spine. When you look at your body from the side, you can see the gentle inward and outward curves of the neck, upper back and lower back, which are necessary for keeping the body properly balanced and aligned over the pelvis. But when viewed from the back, the vertebrae of a healthy spine should form a straight line. In someone with scoliosis, the spine looks more like an "S" or a "C" than an "I". The vertebrae involved in the curve also may rotate to some degree, which can further contribute to the appearance of an uneven waist or shoulders.

Treatment of scoliosis depends on the severity of the curve, along with other factors such as the patient's age and physical condition. Non-surgical treatment, such as bracing, is always the first line of defense, and many scoliosis curves never progress to the point where surgery is necessary. Surgery—specifically, spinal fusion—is recommended for severe curves and for curves that have not responded to non-surgical intervention. Spinal fusion involves placing graft material between the affected vertebrae to encourage them to fuse, or join together. Instrumentation, such as screws, rods, plates and cages, is implanted along the treated area and is a key element because it creates an "internal cast" to support the vertebral structures and redirect stress properly along the spine during the healing process. Ultimately, the goal is to halt the progression of the curve and reduce spinal deformity, to the extent possible, restoring proper spinal stability and alignment.

The reason Dr. Cotrel's design concept is so important is because it was the first to approach spinal correction three-dimensionally, meaning correction was addressed from all three "planes" of the body: coronal (divides the body into front and back halves), sagittal (divides the body into left and right halves) and axial (divides the body into upper and lower halves). Previous instrumentation systems addressed spinal curve correction two-dimensionally, considering only the sagittal and axial planes and not addressing the coronal plane, which is where the "side-to-side" curvature actually resides. By applying pressure to the spine exactly where it's needed and providing the appropriate internal support for each vertebral segment, surgeons could achieve better and more lasting correction, and the bulky, uncomfortable postoperative casts and braces could be eliminated.

Since that inaugural procedure in 1983, Dr. Cotrel and Prof. Dubousset, in collaboration with other researchers in the U.S. and overseas, continued to fine-tune both the instrumentation's design and surgical technique. Originally called Universal Instrumentation, because it could be applied to several areas of spinal pathology requiring correction/stabilization with instrumentation, Dr. Cotrel later renamed it "Cotrel-Dubousset," in honor of his colleague's vital contribution to its success.

Dr. Cotrel and Prof. Dubousset's CD instrumentation was patented in February 1987, and in December cleared by the FDA for marketing. Since then, more than 650,000 surgeries have been performed worldwide using CD® Instrumentation, including the CD HORIZON® LEGACY™ Spinal System, and technology derived from the "CD" design, such as the TSRH® Spinal System.

Now, without further adieu, I'd like to introduce you to Prof. Dubousset, who will provide us with more detail on this groundbreaking technology and its impact on both the spinal device industry and patients' lives.

Me: Tell us about your first meeting with Dr. Yves Cotrel. What did you think about the design he proposed?

Dr. Dubousset: It was towards the end of November 1982 that Yves Cotrel came to Saint Vincent de Paul Hospital in Paris to meet me. He had in his pocket a rough rod with a surface worked in "diamond points," which he had tested at the National Testing Laboratory with closed-body laminar and pedicular hooks and with a small bolt which, by flattening out the unevennesses of the rod, made it possible to fix the rod after the same had been threaded directly or in a reciprocating manner in the channel of the body of the hook.

Other hooks were of the open-body type, and the rod was anchored with a cylindrical slider, which was previously threaded on the rod and fitted into the open body of the hook by sliding, according to the direction of the orientation of the blade of the hook, whether laminar or pedicular; therefore, upwards or downwards. Some had an inclination of the body in relation to the blade to the right or to the left, for Yves believed it facilitated the installation of the rectilinear (i.e., straight line) rod in the hooks, which had been previously placed on the concavity and the convexity of the scoliotic curve.

There also were transverse joining systems, based on the principle Yves previously had provided for the Harrington instrumentation, i.e., the transverse traction device (TTD). The purpose of the transverse system was to reunite the concave rod with the convex rod to obtain stabilization of the fixation, and in particular to oppose the twisting strains that could be seen with the double, parallel Harrington rods, one concave and one convex, used as distraction.

Yves Cotrel's goal was to obtain fixation that made it possible to omit plaster-cast immobilization after arthrodesis straightening surgery of a scoliotic curve, thanks to a concave distraction rod and convex compression between the outer vertebrae of the curve, the two rods brought together between them to form a frame. Likewise, the goal of the rough, diamond-point surface, which Yves Cotrel had studied at length with the metallurgical engineers of the National Testing Laboratory, was to not only ensure good fixation of implants on the rod but also, he thought, for the bone graft to be anchored more firmly on the metallic assembly.

He asked me at that time whether I was interested in operating on a patient with this project, to see whether it was really possible to omit plaster casting after having obtained a reduction of the curve. I immediately said "OK" because I understood instantly the benefits it could offer the patient. The only technical comment I made to him at the time was to replace the cylindrical sliders (blockers) with conical starting sliders, for the sole purpose of more easily entering (like a suppository) in the body of the open hook. So, he asked me to choose from among my patients a candidate with a thoracic curve.

I'll post the rest of my conversation with Prof. Dubousset in my next blog. Please join me again soon here at InsideSpine.com to learn more about his and Dr. Cotrel's early experiences in using and refining the new instrumentation and his thoughts on the impact that this technology has had on the correction of spinal deformity.

If you have specific questions, please send them to me. I'll also be looking for more opportunities to share interesting information with you in the future.

For more information on how to determine if you or someone you know has scoliosis, see our symptoms page on iScoliosis.com.

The materials on this Web site are for your general educational information only. Information you read on this Web site cannot replace the relationship that you have with your health care professional. We do not practice medicine or provide medical services or advice as a part of this Web site. You should always talk to your health care professional for diagnosis and treatment.

Celebrating the 25th Anniversary of CD® Instrumentation and the 20th Anniversary of the TSRH® Spinal System

A Conversation with Professor Jean Dubousset:
Elevating Scoliosis Surgery to a New Plane with Three-Dimensional Correction

Celebrating the 25th Anniversary of CD® Instrumentation and the 20th Anniversary of the TSRH® Spinal System

A Conversation with Professor Jean Dubousset: Elevating Scoliosis Surgery to a New Plane with Three-Dimensional Correction

A Conversation with Professor Jean Dubousset:
Elevating Scoliosis Surgery to a New Plane with Three-Dimensional Correction