Surgical intervention of damaged or compromised bone sites has proven highly beneficial for patients, including, for example, patients with back pain associated with vertebral body damage. The vertebral damage may be due to injury and/or a degenerative condition such as, for example, aging and/or osteoporosis. The damage associated with these conditions may also affect long bones, the pelvis, and other bones. Compression fractures of the vertebrae may have direct impact on spinal nerves, causing pain and other impairment.
Bones of the human skeletal system include mineralized tissue that may be generally categorized into two morphological groups: “cortical” bone and “cancellous” bone. Outer walls of all bones are composed of cortical bone, which is a dense, compact bone structure characterized by a microscopic porosity. Cancellous or “trabecular” bone forms the interior structure of bones. Cancellous bone is composed of a lattice of interconnected slender rods and plates known by the term “trabeculae”.
During certain bone-related procedures, cancellous bone is supplemented by an injection of a palliative (or curative) material employed to stabilize the trabeculae. For example, superior and inferior vertebrae in the spine may be beneficially stabilized by the injection of an appropriate, curable material (e.g., PMMA or other bone cement or bone curable material). In other procedures, percutaneous injection of stabilization material into vertebral compression factors, by, for example, transpedicular or parapedicular approaches, has proven beneficial in relieving pain and stabilizing damaged bone sites. Such techniques are commonly referred to as vertebroplasty, or when implemented with a balloon, as kyphoplasty. In certain cases, vertebral augmentation may not alleviate targeted symptoms, and a spinal fusion procedure may be implemented to align the vertebrae in a manner intended to treat, and alleviate pain and other symptoms associated with, vertebral compression fractures.
A conventional vertebroplasty technique for delivering the bone stabilizing material entails placing a cannula with an internal trocar into the targeted delivery site, generally conducted in a bipedicular manner (i.e., via two pedicles of a vertebra, each of which is located as a thinner portion of cortical bone between the central spinous process and one of the transverse processes of a given vertebra). The cannula and trocar are used in conjunction to pierce the cutaneous layers of a patient above the hard tissue to be supplemented, then to penetrate the hard cortical bone of the vertebra, and finally to traverse into the softer, cancellous bone underlying the cortical bone. After the assembly is positioned in the cancellous bone, the trocar may be removed, leaving the cannula in the appropriate position for delivery of curable material that will reinforce and solidify the target site.
In spinal fusion procedures, metal plates and/or rods are typically attached to two or more adjacent vertebrae by metal screws. Bone graft material may be used to augment the fusion process. Recovery is often more time-consuming and intensive than for vertebroplasty or kyphoplasty. Spinal fusion may be used to treat other conditions including spinal stenosis, disc injuries and degeneration, trauma, infection, and tumors.
There exists a need in the medical device field for improved systems and methods for fusing adjacent vertebrae. In particular, it would be desirable to provide apparatus and methods to provide a fusion method that provides bone augmentation to stabilize vertebrae.
It may be desirable to provide a system and method that provides advantages with regard to reduced complexity, reduced procedure time, and reduced recovery time and patient pain, while maintaining advantages known from kyphoplasty offering a further advantage of a single and/or smaller surgical wound sites rather than those associated with traditional spinal fusion procedures.