Stiffening assembly

#This invention relates to devices that may be varied between bendable and stiffened states, and more particularly to such stiffenable assemblies in tubular arrangements in devices for minimally invasive surgery.

#Minimally invasive surgical tools, such as those used for laparoscopic surgery, are often substantially rigid. Consequently, their reach is limited. To achieve useful triangulation of instruments at an internal surgical site, instruments must be inserted through multiple ports in the patient's body wall.

#Flexible endoscopes that allow passage of two or more instruments to an internal surgical site are being used for surgery because such use requires only a single entry port into the body. But endoscopes typically lack rigidity and lack instrument triangulation at the distal end of the endoscope. Since the surgical instruments experience reactive forces from tissue (e.g., when retracting, suturing, etc.), some endoscopes rely on bracing against surrounding tissue to provide a stable base for the instruments. Other endoscopes rely on a stiffening/rigidizing mechanism. For instance, cables used to steer the endoscope may be locked in position or tensioned to increase friction in the endoscope's joints in order to stiffen the endoscope. But surrounding tissue used for bracing may be soft, and small control cables are subject to stretching due to the moment loads at the endoscope's distal end. Accordingly the flexible endoscope may only be made a limited amount more stiff than its flexible state. In addition, longitudinal tension on control cables used to increase friction between an endoscope's joints may cause the distal tip of the endoscope to move.

#FIG. 1 is a diagrammatic perspective view that illustrates a general configuration of an aspect of the invention.

#FIGS. 2A and 2B are diagrammatic plan views of longitudinal beams bending and sliding with reference to one another as a guide bends along its longitudinal axis.

#FIG. 3 is an exploded perspective diagrammatic view of bendable longitudinal beams in a stiffening mechanism.

#This description and the accompanying drawings that illustrate aspects and embodiments of the present invention should not be taken as limiting—the claims define the protected invention. Various mechanical, compositional, structural, electrical, and operational changes may be made without departing from the spirit and scope of this description and the claims. In some instances, well-known circuits, structures, and techniques have not been shown or described in detail in order not to obscure the invention. Like numbers in two or more figures represent the same or similar elements.

#Further, this description's terminology is not intended to limit the invention. For example, spatially relative terms—such as “beneath”, “below”, “lower”, “above”, “upper”, “proximal”, “distal”, and the like—may be used to describe one element's or feature's relationship to another element or feature as illustrated in the figures. These spatially relative terms are intended to encompass different positions and orientations of the device in use or operation in addition to the position and orientation shown in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be “above” or “over” the other elements or features. Thus, the exemplary term “below” can encompass both positions and orientations of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. Likewise, descriptions of movement along and around various axes includes various special device positions and orientations. In addition, the singular forms “a”, “an”, and “the” are intended to include the plural forms as well, unless the context indicates otherwise. And, the terms “comprises”, “comprising”, “includes”, and the like specify the presence of stated features, steps, operations, elements, and/or components but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups. Components described as coupled may be electrically or mechanically directly coupled, or they may be indirectly coupled via one or more intermediate components.

#FIG. 1 is a diagrammatic perspective view that illustrates a general configuration of an aspect of the invention. FIG. 1 shows a flexible guide 2 having a proximal end 4 and a distal end 6. A longitudinal axis 8 is defined between the proximal and distal ends. Guide 2 is depicted as having at least one longitudinal channel 10 that extends from the proximal end (or nearly so) to the distal end (or nearly so). The single channel 10 shown in FIG. 1 is illustrative of one or more channels, which may be of various and differing diameters. Such channels may be used for, e.g., introducing surgical tools and equipment (e.g., surgical instruments, needle and suture, and the like) to a surgical site, introducing fluid (gas, liquid) to the surgical site, or removing matter from the surgical site (e.g., using suction, biopsy sampling, and the like).