Expandable intervertebral disc dilating cannula

Abstract

In previous applications, the authors have provided Methods and Devices for minimally invasive, percutaneous methods for accomplishing disc dilation, with increase of disc height, as well as accomplishment of an intervertebral fusion, and percutaneous insertion of an artificial disc prosthesis. As an extension of these applications and inventions, the authors now provide for a method of placing an expandable cannula percutaneously into the intervertebral disc space and increasing the disc height with the use of a mechanically driven device either a pneumatically-driven device, or, as an alternative embodiment, a hydraulically-driven device. Its use for general utilization in any percutaneously achieved intervertebral procedure is also contemplated. The device provided utilizes a cannula compose of two or four leaflets that may be constructed from metal, hard plastic, or any other acceptable substance. Lying between the leaflets are expandable envelopes that may be expanded by connecting them to either a pneumatically-driven or hydraulically-driven source. As the medium of choice (fluid or gas) is driven into the envelope, the leaflets expand. In the two-leaflet model, superior and inferior leaflets are present, and these will be driven in a fashion such that the disc space is expanded in a craniocaudal direction. In the four-leaflet embodiment, in addition to expansion of the disc in a craniocaudal direction, there is also expansion in a mediolateral direction. The invention provided is intended for use in the lumbar spine. The authors contemplate the development of an analogous invention in the cervical spine.

Dependencies are inferred from the claim text.