News Column

Patent Issued for Implant Apparatus and Method Including Tee and Screw Mechanism for Spinal Fusion

July 30, 2014

By a News Reporter-Staff News Editor at Biotech Week -- A patent by the inventor Medina, Mark Patrick (Torrance, CA), filed on April 3, 2012, was published online on July 15, 2014, according to news reporting originating from Alexandria, Virginia, by NewsRx correspondents (see also Medevice IP Holdings, LLC).

Patent number 8778027 is assigned to Medevice IP Holdings, LLC (Albuquerque, NM).

The following quote was obtained by the news editors from the background information supplied by the inventors: "In some instances, an intervertebral disc that becomes degenerated may need to be partially or fully removed from a spinal column. Intervertebral discs can degenerate due to various causes such as, for example, trauma, disease, or aging. Removal or partial removal of an intervertebral disc destabilizes the spinal column. A spinal implant may thus be inserted into a disc space created by the removal or partial removal of an intervertebral disc. The spinal implant may maintain the height of the spine and restore stability to the spine. Bone then grows from the adjacent vertebrae into the spinal implant. The bone growth fuses the adjacent vertebrae.

"A spinal implant can be inserted utilizing an anterior, transforaminal, oblique, posterior or lateral spinal approach. For an anterior approach, extensive vessel retraction is often required and many vertebral levels are not readily accessible from this approach. Another approach is a posterior approach. This approach typically requires that both sides of the disc space on either side of the spinal cord be surgically exposed, which may require a substantial incision or multiple access locations, as well as extensive retraction of the spinal cord.

"Yet another approach is a postero-lateral approach to the disc space. The posterior-lateral approach is employed in a posterior lumbar interbody fusion (PLIF) or transforaminal lumber interbody fusion (TLIF) procedure, which may be performed as an open technique, which requires making a larger incision along the middle of the back. Through this incision, the surgeon then cuts away, or retracts, spinal muscles and tissue to access the vertebrae and disc space. The TLIF procedure may also be performed as a minimally invasive or as an extreme lateral interbody fusion procedure that involves a retroperitoneal transpoas approach to the lumbar spine as an alternative to 'open' fusion surgery. In the minimally invasive procedure, the surgeon employs much smaller incisions, avoids disrupting major muscles and tissues in the back and reduces the amount of muscle and tissue that is cut or retracted.

"Anterior Lumbar Interbody Fusion (ALIF) using threaded devices such as cages and bone dowels have been in use for over ten years. Initially, threaded cages or dowels were expected to act as a stand-alone device that would promote fusion and maintain disc height without the need for posterior surgery and instrumentation of the spine. In spite of fusion rates better than 90 percent for single level fusion and 65 percent for two-level fusion, significant subsidence has been observed on follow-up X-rays at varying times following the procedure. This subsidence, or slow insinuation of the threaded devices into the vertebral bodies, has resulted in lost disc height, which in some patients has resulted in the failure to fuse and the recurrence of often very painful symptoms.

"The implants may be constructed of any biocompatible materials sufficiently strong to maintain spinal distraction including, but not limited to, bone, metals, ceramics and/or polymers. Implants may be packed with bone graft or a synthetic bone graft substitute to facilitate spinal fusion. Implants may have a variety of shapes, which include, but are not limited to, threaded cylinders, unthreaded cylinders, and parallelepipeds.

"A protective sleeve can be used during preparation and insertion of a spinal implant. The protective sleeve serves to protect abdominal organs, blood vessels and other tissue during a spinal implant procedure using an anterior approach. The sleeve typically extends above the surgical opening during use. The sleeve maintains distraction of the vertebrae. Also, the sleeve serves as an alignment guide for tool and implant insertion during the surgical procedure. Protective sleeves can also be used during a spinal fusion procedure using a posterior or lateral approach.

"Typically, most surgical corrections of a disc space include at least a partial discectomy, which is followed by restoration of normal disc space height and, in some instances, fusion of the adjacent vertebral bodies. Restoration of normal disc space height generally involves the implantation of a spacer and fusion typically involves inclusion of bone graft or bone graft substitute material into the intervertebral disc space to create bony fusion. Fusion rods may also be employed. Some implants further provide artificial dynamics to the spine. Such techniques for achieving interbody fusion or for providing artificial disc functions are well known.

"The inter-vertebral spacing (i.e., between neighboring vertebrae) in a healthy spine can be maintained via a compressible and somewhat elastic disc. The disc serves to allow the spine to move about the various axes of rotation and through the various arcs and movements required for normal mobility. The elasticity of the disc maintains spacing between the vertebrae, allowing room or clearance for compression of neighboring vertebrae, during flexion and lateral bending of the spine. In addition, the disc allows relative rotation about the vertical axis of neighboring vertebrae, allowing twisting of the shoulders relative to the hips and pelvis. Clearance between neighboring vertebrae maintained by a healthy disc is also important to allow nerves from the spinal chord to extend out of the spine, between neighboring vertebrae, without being squeezed or impinged by the vertebrae.

"In situations (based upon injury or otherwise) where a disc is not functioning properly, the inter-vertebral disc tends to compress, and in doing so pressure is exerted on nerves extending from the spinal cord by this reduced inter-vertebral spacing. Various other types of nerve problems may be experienced in the spine, such as exiting nerve root compression in neural foramen, passing nerve root compression. A few medical procedures have been devised to alleviate such nerve compression and the pain that results from nerve pressure. Many of these procedures revolve around attempts to prevent the vertebrae from moving too close to each other by surgically removing an improperly functioning disc and replacing it with a lumber interbody fusion (LIF) device. Although prior interbody devices, including LIF cage devices, may be effective at improving patient condition, the vertebrae of the spine, body organs, the spinal cord, other nerves, and other adjacent bodily structures make obtaining surgical access to the location between the vertebrae where the LIF cage is to be installed difficult.

"In case of lateral approach, it would be desirable to reduce the size of the LIF/VBR cage to minimize the size for the required surgical opening for installation of the LIF/VBR cage, while maintaining high strength, durability and reliability of the LIF/VBR cage device. Instruments and lateral implants are not necessarily suited to efficiently distract the disc space without damaging the adjacent endplates. In an effort to address the foregoing difficulties, it is believed that the implant device for spinal fusion from lateral approach, as discussed herein, can address many of the problems with traditional lateral implants."

In addition to the background information obtained for this patent, NewsRx journalists also obtained the inventor's summary information for this patent: "The following summary is provided to facilitate an understanding of some of the innovative features unique to the disclosed embodiment and is not intended to be a full description. A full appreciation of the various aspects of the embodiments disclosed herein can be gained by taking the entire specification, claims, drawings, and abstract as a whole.

"It is, therefore, one aspect of the disclosed embodiments to provide for spinal implants.

"It is another aspect of the disclosed embodiments to provide for vertebral body spacers.

"It is yet another aspect of the disclosed embodiments to provide for implanting techniques and device for spinal fusion from lateral approach.

"It is also an aspect of the disclosed embodiments to provide a spinal implant device with a cage apparatus that includes four boxes or cavities and in which the autograft, allograft or scaffold material does not migrate when such a cage apparatus is deployed or expanded.

"It is a further aspect of the disclosed embodiments to provide for an inner working male and female Tee component and screw mechanism that contains a center control post that allows a user to open and close the disclosed system/apparatus in a controlled manner.

"The aforementioned aspects and other objectives and advantages can now be achieved as described herein. An implant apparatus and a method for spinal fusion from oblique, lateral, ALIF, PLIF, and TLIF approach are disclosed. The apparatus can be configured to include an expandable implant cage and an inserter. The cage can be inserted between endplates of upper and lower vertebra using an oblique, lateral, ALIF, PLIF, and/or TLIF approach. The cage generally includes a male and female screw configuration and a cage expansion mechanism. The inserter inserts the cage in a spinal disc space and tightens the male and female screw arrangement. Once the cage is inserted to the desired position, viewed by X-ray you will begin to tighten the male portion of the screw in the device, and continue to tighten until final deployment of cage has been achieved. This provides a much greater footprint that allows the device to reach the cortical ring or apophyseal ring of the vertebral body. Tightening of male and female screw arrangement operates the cage expansion mechanism to expand the cage size. The cage can be inserted through a smaller surgical opening and then expanded to a full size assembly between the vertebrae. The disclosed spinal implant device including the cage with its four boxes or cavities allows the autograft, allograft or scaffold material to not migrate when the cage is deployed or expanded. Such a spinal fusion apparatus includes an inner working male and female Tee component and screw mechanism that contains a center control post that allows a user to open and close the disclosed system/apparatus in a controlled manner."

URL and more information on this patent, see: Medina, Mark Patrick. Implant Apparatus and Method Including Tee and Screw Mechanism for Spinal Fusion. U.S. Patent Number 8778027, filed April 3, 2012, and published online on July 15, 2014. Patent URL:

Keywords for this news article include: Arthrodesis, Bioengineering, Biomedical Engineering, Biomedicine, Bone Research, Central Nervous System, Medevice IP Holdings, Medevice IP Holdings LLC, Medical Devices, Spinal Cord, Spinal Fusion, Surgery, Tissue Engineering.

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Source: Biotech Week

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