Dynamic Soft Stabilization

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A few weeks ago, I was fortunate enough to get a private lesson in the state of posterior stabilization systems from Dr. Bertagnoli. He’s been developing the next generation system and started implanting them last April. (See news release below.)

The new system is called DSS for Dynamic Soft Stabilization. It’s similar to Dynesys in that it uses pedicle screws with a flexible spacer, but with many improvements. Dynesys spacers are of fixed length. Along with the very wide screw head spacing and the tight cord, this results in a somewhat rigid system with almost no motion in lateral bending. It accomplishes the design goals of allowing some continued motion while providing stabilization, but it does it in a way that does not allow anything close to the normal kinematics of the implanted levels. Because of this, the screw loading remains high and the stiff system can still transmit additional load to the adjacent segments.

The design goals for DSS included allowing more natural kinematics, but only in a neutral or ‘safe’ zone. For most of us, pain is generated when we weight the disc, or when we overload portions of the system by venturing into more extreme ranges of motion. (Bending, lifting, twisting.) If natural kinematics are maintained, but motion is maintained with the neutral zone, the system stays in the ‘safe’ range.

The DSS system is a modular design that includes the ‘soft’ module that provides flexibility not only in flexion and extension, but also in lateral bending. Allowing expansion in flexion and compression in extension, compound movements and lateral bending produces more normal kinematics than does Dynesys. This ‘softer’ system should provide reduced loading on adjacent segments compared to Dynesys and also reduced loading on the screws.

One of the most important features of DSS is the modular design. In addition to the flexible spacers, the DSS system includes rigid spacers for traditional fusion. With this modular system, multi-level procedures can easily mix fusion and soft stabilization. More importantly, if the soft stabilization must ultimately be revised to fusion, a small procedure to remove the flexible spacers and replace them with rigid ones will be all that is necessary. The screws… the other levels can all be left alone… just replace the appropriate segments. The easy revision promised for Dynesys is great in theory… not in practice.

This post is written from memory and a few brief notes. If I discover errors or items that should be explained more fully, I’ll post more. Remember… I’m not a doctor and I'm just sharing what I’ve learned. Take everything I say with a grain of salt.

Mark

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Press release located on Paradigm Spine's website.

NEW YORK—April 30, 2007—Paradigm Spine, LLC, a developer of innovative non-fusion spinal implant solutions, announced that it has received a European Union CE Mark for its DSSTM implantable dynamic spine stabilization system. The CE Mark will allow the company to begin marketing the DSSTM system in Europe and many other countries that recognize the certification.

The first surgery involving the DSSTM system was performed on April 27th, 2007 in Straubing, Germany by Dr. Rudolf Bertagnoli.

The DSSTM system is a pedicle-screw based, implantable dynamic spine stabilization system indicated for degenerative disc disease (DDD) of the lumbar spine. The DSSTM system incorporates a hybrid philosophy, combining elements of fusion and motion preservation.

The system was developed over a two-year period in close cooperation with Professor Hans- Joachim Wilke, a world-renowned Professor of Biomechanics from the University of Ulm in Germany, and Dr. Bertagnoli, the most experienced spine arthroplasty surgeon worldwide.

The modularity of the DSSTM system enables the combination of DSS dynamic couplers with DSS fusion couplers at adjacent levels. Therefore, one segment may have functionally dynamic stabilization (non-fusion) while an adjacent segment has rigid segmental fixation (fusion) under the same system.

The DSS dynamic coupler increases the stiffness of the affected motion segment and restricts the range of motion in flexion, extension, lateral bending and rotation while preserving motion. By selecting the appropriate size DSS dynamic coupler, the posterior segmental height can also be adjusted. The DSS fusion coupler provides rigid segmental fixation utilizing the same instrument set. One of the features and benefits of the system is the use of percutaneous screw
positioning that facilitates a minimally invasive muscle-sparing approach.

Marc R. Viscogliosi, Chief Executive Officer of Paradigm Spine, said, “The DSSTM system is the product of collaborative thinking between two of the world’s most experienced spine motion- preserving experts, from both a scientific and clinical point-of-view.”

“The DSSTM system is one of the first truly dynamic stabilization systems because it increases segmental stiffness while controlling specific ranges of motion as the patient goes about his or her daily activities,” he noted. “We are particularly excited to have benefited from the enthusiastic development efforts and significant contributions of Professor Wilke and Dr. Bertagnoli.”

Professor Wilke said, “I worked very closely with the Company on incorporating the key strategic and scientific elements of the ranges and types of motion which need to be controlled by a true dynamic stabilization system. Specifically, we designed the system to focus on controlling ‘active zone’ motions, which are normally associated with pathologic painful arcs of motion.”

Professor Wilke further added, “This product reflects what we have learned about the function of the human spine from multiple spine experiments over many years, based on studies conducted with our validated Finite Element model of a lumbar spinal segment.”

Dr. Bertagnoli said, “The surgery on Friday [April 27] went very well and I believe the DSSTM system has the potential to become an important new option in the continuum of spine care.
Having used most of the major spine arthroplasty products I, like Professor Wilke, am convinced of the uniqueness and potential impact of the DSSTM system for the treatment of my patients.”

The DSSTM system is Paradigm Spine’s fourth product to receive a CE Mark, following the coflex® interspinous implant, the DCITM dynamic cervical implant, which received the CE Mark on December 5, 2006; and the coflex-FTM implant system which received the CE Mark on December 15, 2006.


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About Paradigm Spine, LLC

Paradigm Spine is a company focused on providing indication specific posterior non-fusion solutions for orthopedic spine surgeons and neurosurgeons focused on treating spinal conditions and diseases.

The company’s founding philosophy is “Surgeon Centric, Indication Specific, Data Driven”, and focuses on providing the best clinical outcomes for patients suffering from chronic back pain.
The Company has 40 employees at its New York headquarters and office in Wurmlingen, Germany, including a 7-member direct sales force in Germany.

The company is concentrating on building a multi-product non-fusion portfolio. The company’s signature product is the coflexTM posterior, non-fusion interspinous dynamically-functional implant. The company has commenced a multi-center IDE clinical trial of the coflexTM implant in the United States.