Fall 2008 Issue

The Edge Of Innovation
Nucleus Replacement Technology

Nucleus replacement represents the next wave of motion-preserving procedures for patients suffering from degenerative disc disease. On the top is the Nucore Injectable Disc Nucleus (red) shown interdigitating with a normal disc after injection into the defect. On the bottom is the Nubac 2-piece mechanical nucleus ready for insertion.
Providing spine treatment options that also preserve a patient's motion is always a priority for the neurosurgeons of Carolina Neurosurgery & Spine Associates. Our doctors were the first in the Carolinas to use an artificial disc, as an alternative to spinal fusion, to treat degenerative disc disease (DDD). Unlike spinal fusion, spine arthroplasty technology, such as the artificial disc, has allowed surgeons to relieve pain while preserving motion for patients and protecting adjacent disc levels.

A new category of this spine arthroplasty technology is now on the horizon - nucleus disc replacement. Carolina Neurosurgery & Spine Associates neurosurgeon, Dom Coric, M.D., recently co-wrote a Journal of Neurosurgery article in which he and his colleague, Praveen Mummaneni, M.D., describe and categorize the various nucleus disc replacement devices now in development.

In the article, Dr. Coric explains that nucleus disc replacement or partial disc replacement (PDR) technology is an innovative treatment option focused on helping patients with early to moderate DDD. It offers a less invasive alternative to traditional fusion or total disc replacement (TDR) techniques.

Anticipated Advantages Of Nucleus Replacement Include:
• Minimally invasive procedures
• Multiple approach options
• Multiple revision options including TDR and fusion


Intraoperative fluoroscopy image of intradiscal application needle for injectable disc nucleus.
Classifications Of Nucleus Replacement Devices
There are several nucleus replacement devices in development with current clinical trials. Dr. Coric places these devices into two classifications: elasometric and mechanical. Possible advantages of elasometric devices are their ability to reproduce the uniform stress distribution and shock absorption found in the natural nucleus. Some elasometric devices are injected in liquid form into the nucleus void and form in place. Others are composed of preformed, precured polymers. Biocompatibility, long-term durability and possible leakage are all challenges facing developers of these devices.

Mechanical devices can be one or two pieces and are composed of various biomaterials including metal and pyrolytic carbon. Advantages of these devices are their strength and durability; however, shock absorption and even stress distribution are potential challenges.


While nucleus replacement technology is still in the investigational stages, it shows great potential, especially for patients with degenerative diseases more complex than simple disc herniation, but less advanced than complex DDD. Carolina Neurosurgery & Spine Associates will continue to follow the development of nucleus replacement devices and access the ongoing clinical trials for this innovative technology.

For more information about motion-preserving spine procedures, or to contact Dom Coric, M.D., call 800-344-6716.


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