Nucleus Replacement System for Degenerative Disc Disease - Medical / Health Care
Degenerative disc disease (DDD) is a term generally applied to degenerative changes seen in the intervertebral disc in patients that have low back pain. In some people, the affected disc can be the source of pain. Such patients have discogenic low back pain (dLBP). Figure 1 provides an overview of the anatomy of a healthy intervertebral disc.
Healthy intervertebral discs act like shock absorbers for the spine (Figure 2), however, as the body ages, degenerative changes occur as part of the body and tissue’s normal wear and tear. Furthermore, the cause of dLBP may be directly related to injury sustained by the nucleus pulposus (NP). This injury can be due to excessive wear and tear from poor biomechanics or any significant accident or injury. The damage to the disc leads to inflammation within the NP and microtearing of the annulus of the disc that contains the nucleus. The nucleus tissue has poor blood supply and inflammation takes very long to resolve, if it can be resolved at all. Additionally, abnormally sensitive nerve endings grow into these microtears and render the disc hypersensitive to movements that do not otherwise cause pain. Other spinal elements may be affected as degeneration progresses. Figure 3 illustrates some of the degenerative changes that might occur within the lumbar spine.
Degenerative disc changes are often characterized by a loss of water content in the disc (confirmed using a T-2 weighted MRI sequence — see Figure 4) and various changes to its elastic and mechanical properties. This can lead to dLBP. It is important to note that although degenerative changes may be observed, the pain may be unremarkable. Conversely, imaging may reveal very mild degenerative changes, yet the patient may be experiencing significant pain.
There are numerous treatments for dLBP ranging from conservative therapies such as physical therapy and nonsteroidal anti-inflammatory drugs (NSAIDS), to more invasive surgical options such as spinal fusion, total disc replacement, and Nucleus Replacement in appropriate patients. See Treatment Options for more information.
Historically, conservative treatment options for Discogenic Low Back Pain (dLBP) have included physical therapy, pharmaceutical pain management, and various intradiscal injections. While conservative therapies have shown efficacy, some patients may be unresponsive, and a surgeon might consider more invasive surgical options after failed conservative treatment.
Spinal Fusion and Total Disc Replacement have been surgical treatment options for latter stages of symptomatic Disc Degeneration. Spinal Stabilization Technologies™ introduces a potentially less invasive alternative surgical treatment: The PerQdisc™ Nucleus Replacement System.
PerQdisc Nucleus Replacement
Nucleus replacement is a surgical procedure that limits tissue disruption to the intervertebral disc. Unlike fusion techniques, and TDR procedures that require aggressive resection of all or a portion of the disc, the PerQdisc surgical procedure aims to preserve the annulus fibrosus (AF) and cartilaginous endplates.
The PerQdisc Nucleus Replacement offers an anatomical and biomechanical, motion-preserving, surgical alternative to fusion and total disc replacement. The PerQdisc replaces the physical space of the nucleus, in an effort to recreate physiological motion, and redistribute the weight bearing forces and mechanical properties of the disc in a more natural fashion.
The PerQdisc is thought to treat dLBP by removing the damaged nucleus tissue while the nucleus replacement implant supports the annulus fibers and nearby tissue. The PerQdisc surgical technique requires a small dilation into the AF, which facilitates access and resection of the nucleus pulposus, allowing for a focused area of attention with minimal damage to surrounding tissue.
The PerQdisc’s innovative technology provides a patient-specific, form-fitting, custom implant, unique to each individual patient.Spinal Fusion
Spinal Fusion is a surgical procedure where two or more of the vertebrae of the spine are joined together using different combinations of implants and hardware. There are several varied surgical techniques, and devices that may be used to perform a spinal fusion. The procedure is designed to restrict movement in the involved segment in order to relieve pain by preventing abnormal motion in the degenerated disc that leads to inflammation and irritation. This lack of mobility has caused concern about degeneration at adjacent levels that need to make up the difference in the loss of flexibility in the spine.
A Total Disc Replacement (TDR) is an alternative to fusion surgery. A TDR surgery involves removing the intervertebral disc and replacing it with an articulating device that is intended to allow for movement in the affected segment. The goal of motion preserving devices is to remove the affected disc while decreasing the incident of adjacent segment degeneration. Although a TDR is designed to preserve motion, total resection of the disc is required, the resulting movements are not fully physiological, and there are limited sizing options available.