Device for Intervertebral Assisted Motion (DIAM)
This device is primarily a shock absorber that fits in-between two vertebrae. The shape of the implant provides stability by means of extended wings bracing the spinous processes. It claims to allow "optimal mechanical behavior in compression and flexion." It is inserted in a "mini-invasive" posterior surgery where part of the intraspinous ligament is removed and then the implant is fastened between two vertebrae using ligatures that are passed around the upper and lower spinous processes.
Materials:
The Diam is a silicone interspinal cushioning device covered with polyethylene.
Sizes:
8-14mm
Surgical Procedure:
The site for the implant is prepared by elevating the supraspinous ligament, resecting the interspinous neo-contacts, trimming the spinous processes, and smoothing the lamina-spinous process.
The procedure can be carried out in posterior way
or lateral way.
The lateral way allows for no resection of the posterior ligament, while the posterior way requires the resection of the posterior ligament. The site is prepared by trimming the lateral surfaces of the spinous process, resecting osteophytes, and smoothing the articul;ar surface between the spinous process and the inferior lamina to optimize fitting.
A distractor is applied the the vertebrae are between ten and fourteen millimeters apart.
The implant is inserted. Each ligament is passed around the spinous process and tensioned. Every ligament is then secured with a clamp and the implant procedure is finished.
Indications:
- Disk herniation
- Bulging disc
- Central and foraminal stenosis
- Facet arthopathy
- Adjacent segment disease after fusion
Effect:
The DIAM's function is to reduce the intradiscal pressure, to enable the ligament structure functional again and control the excess movement of the degenerated segment. Furthermore, the implant avoids facet impingement. The resistance to flexion is controlled by decompression of the implant and then by stretching the other (passive) structures: muscles, fascia and ligaments. During extension the implant continues to be compressed until it reaches the limit of compressibility.
Studies:
In the Dinoi study, one hundred and fifty two patients were treated with the DIAM. Reportedly ninety two percent of the participants were satisfied with the results. However, only fifty seven of the patients in the study were suffering from stenosis, and this was foraminal stenosis. Also, no indication was given as to the relief these specific patients recieved or this device's effectiveness in treating lumbar spinal stenosis.
Success Rates:
There is no study of this device's success in treating lumbar spinal stenosis.
Availability:
While availabile in Europe, it is not available in the US and does not have an IDE study.