The lower back can be exposed to great force and pressure from normal daily tasks, and it’s common to see the Lumbar spine become painful and symptomatic over time. This can be caused by the natural ageing process, or by unexpected injury.
If a patient cannot manage their symptoms with conservative treatments like physiotherapy and exercise programs, surgery might be indicated. The goal of any spinal surgery is to decrease pain, correct the bony-spinal deformity, and improve stability.
Different techniques, equipment, materials, and medical devices are utilized in all spinal procedures. The procedures can be performed through a traditional open incision or via a minimally invasive procedure depending on the patient’s anatomy, condition, and diagnosis. For patients requiring a spine fusion or fixation, the older generation of devices used stiff rods, while newer ones allow for flexibility and mobility due to the hinged screw attached to stabilizing rods.
Dynamic Stabilization System (DSS)
Dynamic Stabilization System (DSS) is a unique surgical technique that uses a single-level system for non-cervical vertebrae fixation from the T4 to S1 to provide immobilization and stabilization of adult spinal segments [3,4].
It is used as an alternative to fusion in the treatment of acute and chronic conditions or deformities of the thoracic, lumbar, and sacral spine. DSS allows for some movement of the spine, but also maintains enough stability to prevent excess movement [3,4].
Pedicle-based dynamic devices unload the pressure on the degenerated disc and facets and, thus, have the potential to reduce pain associated with these damaged structures.
DSS can also be used alongside Total Disc Replacement (TDR) in the Lumbar Spine to create a 360 degree motion-preserving solution in carefully selected patients.
Furthermore, these devices can be used to prevent disease to adjacent structures, and can stabilize posterior destabilizing surgeries such as wide laminectomy and facetectomy .
For patients looking to avoid rigid spine fixation (fusion) DSS systems are similar to Total Facet Joint Replacement, which is also a motion-preserving technology that has been used in Europe for 10+ years, and is now being studied by the FDA in the United States.
A Scientific Study of DSS
The Cosmic® system is a pedicle screw-based dynamic stabilization system that was studied to determine segmental mobility and load sharing between the implant system and the spinal column . The system is built by Ulrich Medical, a German medical technology company with over 100 years of history.
The purpose of the study was to assess the clinical and radiologic results in patients who had been treated using dynamic stabilization with a hinged screw head system. The threaded part of the screw is coated with bioactive calcium phosphate .
One such coating is called Bonit and is used extensively in dental implants and meets the requirements for accelerated formation of new bone. The coating is a thin, bioactive calcium phosphate surface that is applied to the implant by electrochemical deposition, resulting in a fine, crystalline structure with improved solubility and resorption. This process eliminates hard particles and subsequent flaking, and the coating process ensures consistent coverage of complex implant screws .
The BONIT® coating is made of brushite (mineral) and is known for its excellent bio-compatibility and forms a reservoir for calcium and phosphate ions that support bone apposition. During the process of mineralization, it supports the natural osseointegration process .
The advantages of the DSS Screw Bonit coating are:
- Complete, controlled resorption and replacement by autogenous bone
- Ideal conditions for osteoblasts to grow and provide a large amount of free calcium and phosphate reservoir for the implant.
- Faster and more complete healing
- No flaking of the particles in the implant coating
In the following study of the Cosmic System (a flexible screw system), eighteen-patients were followed for more than one year after dynamic stabilization with the Cosmic system. The following parameters were assessed: age, sex, visual analog scale (VAS) for the leg and back, the Oswestry Disability Index (ODI), complications related to the operation, range of motion (ROM) of the adjacent segments, implantation segment and the whole lumbar spine .
The results were as follows: the mean preoperative ODI and VAS scores were significantly decreased after the operation. ROM at both the top and bottom adjacent spine segments did not change significantly postoperatively. The average preoperative ROM of the implanted segment was less postoperatively. However, the mean ROM of the whole lumbar spine did not change dramatically postoperatively.
The conclusion was that lumbar stabilization using a hinged screw head system did not negatively influence adjacent segment motion and offered improved clinical outcomes at the 1-year postoperative period .
This new type of flexible spine fixation can provide favorable outcomes for carefully selected patient candidates, and Spine Connection offers Dynamic Stabilization Systems (DSS) with our German Specialists whom are respected as leaders in the field of motion-preserving spine surgery.
1. Dong, Hwa & Heo, & Yang, Jin Seo & Dong, Yang & Heo, Dong & Kang, Suk-Hyung & Cho, Yong-Jun. (2011). Pedicle screw-based Dynamic Stabilization with a Hinged Screw Head System in the Treatment of Lumbar Degenerative Disorders. Korean Journal of Spine. 8. 10.14245/kjs.2011.8.2.102.
4. Di Silvestre, Mario et al. Degenerative lumbar scoliosis in elderly patients: dynamic stabilization without fusion versus posterior instrumented fusion The Spine Journal, Volume 14, Issue 1, 1 – 10