Surgical access methods for use with delicate tissues

#This disclosure relates to surgical access instruments for use with delicate tissues and methods of use.

#Traditional surgical brain retractors are thin, firm or malleable bands of steel or other metal alloys, with abrupt or well-defined edges and have limited surface areas. The common structural form of the standard retractors is a simple strip of metal consisting of a metal strip which can be bent by hand and the surface of which typically is used to pull apart or spread delicate tissue. The strip typically is clearly outlined on the brain after a few minutes, and particularly noticeable are the pressure marks from the lateral spatula edges which indicate a high local compression stress. These traditional retractors can be introduced into the tissue of the brain or along brain surfaces, and then pulled with force to either separate or elevate the brain tissue during surgery. This method allows the target area to be illuminated and visualized in order to perform the surgical procedure. However, brain tissue is quite soft and delicate, particularly after trauma, loss of blood supply, or in the presence of brain edema. The brain tissue is a gel-like substance that can be easily damaged, and a complication known as “retraction injury” can occur, sometimes resulting in compromised brain function. The brain tissues can be torn by the relatively sharp edges of these retractors, and/or the retracted brain can lose blood supply when the local pressure beneath the retractor is greater than venous pressure. The result can be ischemic changes in the underlying brain and/or the more serious complication of venous brain infarction.

#The combination factors including the softness of the brain tissue, and the effects of sharp, blunt edges and limited surface area of traditional metal band retractor also results in limited visualization of the surgical target area. The brain tends to extend beyond or “droop” around the edges of the retractor, limiting the area necessary for lighting and reducing overall visibility.

#The present invention can best be understood in connection with the accompanying drawings. It is noted that the invention is not limited to the precise embodiments shown in drawings, in which:

#FIG. 1 is a view of a patient with a retractor assembly and a buttress channel positioned adjacent to a top of the head and lower skull.

#FIG. 2 is a perspective of retractor assembly of FIG. 1.

#This disclosure relates to a surgical instrument assembly and system for use with delicate tissues and methods of using the instrument assembly. The instruments are designed for use during surgery on delicate tissues, such as brain and breast tissues, although they may be used in any medical context. The instrument assembly includes several portions, such as, an introducer portion, a tissue access channel retractor portion (“channel portion”) having at least one handle portion, and a stylette portion. These instrument portions are formed to maximize the surface area of the retractor, which distributes pressure approximately equally though out the surrounding tissues and minimizes effective localized retraction pressure on the tissues in contact or immediately surrounding the instrument.

#In one embodiment, the surgical instrument assembly can be a retractor in the form of an arch or arc shape, into which an arch or arc shaped wedge introducer may be inserted for surgical access to the external portions or surfaces of the brain.

#In another embodiment, the surgical instrument assembly can be a retractor in the form of a wedge with a tapered elliptical cross sectional shape, into which a tapered elliptical cross sectional introducer may be inserted for surgical access to the external portions or surfaces of the brain.