Surgery, whether of the spine or other areas of the body, is often complex and routinely involves the need for highly experienced medical staff, in addition to well-designed and well-manufactured implants, made to exacting specifications. Often the implants take the form of various types of hardware. In the area of spinal fixation, for example, various spinal fixation devices have been developed in the art. Some examples of such fixation devices include spinal rods, plates, corpectomy cages, and intervertebral discs, to name but a few. Spinal fixation rods are fixation devices configured to fix adjacent vertebrae of a spine relative to each other. The rods provide stabilization of the spine till fusion occurs. The spinal fixation rods are often used in spinal surgeries to repair spinal abnormalities, whether related to injury or otherwise. The spinal rods are configured to attach to the vertebrae using, for example, anchoring devices like pedicle screws and hooks.
Patients often experience extreme and debilitating pain because of spinal column injuries or from spinal column disorders such as spondylolisthesis and scoliosis. Pain may be attributed to issues of the spine as related to degeneration, deformity, and/or injury. Often a typical course of treatment involves surgical spinal fixation utilizing spinal fixation rods that mechanically immobilize areas of the spine causing, ideally, the eventual fusion of the treated vertebrae.
Sometimes additional surgical procedures, known as revision surgeries, become necessary. Several causes exist for the need for revision surgeries. For example, pseudarthrosis (failure to achieve solid fusion) may have occurred, which can be due to various causes such as poor tissue healing, improper implant placement or securement, implant failure, or to patient-related factors. Sometimes revision surgeries are indicated even after successful initial surgeries, given that the function and shape of the spine can deteriorate with age. Also, after prolonged use, the spinal fixation rods may move or become dislodged or unstable, or even bend or break.
Revision surgery is also required to treat adjacent segment disease (“ASD”). Spinal fusion recipients may be at risk for developing ASD, a condition in which the motion segments adjacent to the fused vertebral segments experience higher rates of degeneration or deterioration due to an increase in vertebral loading, higher intradiscal pressures, increased range of motion, and increased facet motion. Treatment options for ASD begin with determining whether the primary fusion is intact. If so, then a revision surgery with a revision connector is a likely course of action.
When considering spinal fusion revision surgery options, a few revision connectors are known, such as the “Revere Addition Revision System” and the “Expedium Universal Connector”. However, these connectors suffer from various drawbacks. First, these prior connectors are difficult to connect to the spinal level above the targeted level. This may be due to scar tissue or fusion mass that has developed in the lateral “gutters” across the transverse process. Second, such connectors add significant profile to the implant, both laterally and in height. Increased height can cause problems post-surgery when patients can feel the implants under their skin. Sometimes this leads to deep superficial pain. Third, prior art revision connectors do not achieve adequate stability in-line with the primary rod. Fourth, some prior art connectors are not ideal for minimally invasive surgical implantation techniques.
What is needed is a universal revision connector that is easy to install, with minimal profile, and that can sit in-line, nearly in-line, and/or at desired angles with the primary fusion rod. The connector ideally minimizes the disruption of the previous fusion mass and limposes less violation of the scar tissue. The stabilization may be extended to the next level above or below the fusion. Additional benefit is also achieved with a connector that can be inserted percutaneously. Ideally, a connector is desired that is not only suitable for revision surgeries, but also for primary fusion surgeries. The present connector provides vast improvement over such existing revision connectors.