The present invention relates to a clamping device for interconnecting two elongate elements.
The clamping device has been devised particularly, although not necessarily solely, for use with surgical retractors.
In surgical operations requiring access to internal organs and bone structures, it is common to use retractors to hold back tissue about the surgical site, so as to expose the area in which surgery is to be performed. Typically, a retractor includes a retractor blade which engages the tissue, and a retractor shaft onto which the retractor blade is mounted. The retractor is attached to a retractor support structure by some form of clamping device. The retractor support structure typically includes a rail which the clamping device can engage to thereby connect the retractor to the retractor support structure.
It is important that the clamping devices allow the retractors to be conveniently positioned on the retractor support structure and to be conveniently adjusted as necessary to achieve appropriate positioning with respect to the surgical site. Additionally, it is important that the clamping devices should not pose any significant obstruction to access to the surgical site and to movement of personnel about the surgical site, during the surgical procedure.
Various types of clamping devices have been proposed including those disclosed in U.S. Pat. Nos. 5,727,899 (Dobrovolny), 5,792,046 (Dobrovolny) and 5,888,197 (Mulac). Each of those patents discloses a clamping device which includes a first clamping member for releasably engaging a retractor shaft, a second clamping member for releasably engaging a rail forming part of a retractor support structure, and a shaft which extends between the first and second clamping members and which is operable in association with a camming mechanism to cause the first and second clamping members to move between clamping and non-clamping conditions. Each clamping member includes a mounting section which is mounted on the shaft and a clamping section which is offset from the shaft. Typically, the clamping section includes a clamping aperture in which the component undergoing clamping is received. While such arrangements have proved satisfactory in operation, they do suffer from several deficiencies.
One deficiency is that the clamping device does not lend itself to a compact construction owing to the fact that the clamping section of each clamping member is offset with respect to the shaft on which the clamping members are supported.
Secondly, the offset relationship between the shaft of the clamping device and the retractor shaft renders the retractor vulnerable to deflection in the event of accidental impact during the surgical procedure.
Thirdly, cleaning of and sterilisation of the clamping devices is rendered difficult where they contain large numbers of operational parts. Furthermore, it can sometimes be difficult to insert the retractor shaft of a retractor in the clamping aperture of the appropriate clamping member owing to the close tolerances required for the clamping aperture in order for it to effectively move between clamping and non-clamping conditions upon operation of the clamping device. As a result of the close tolerances, there is little opportunity to accommodate misalignment between the retractor shaft and the clamping aperture when the clamping shaft is being presented to the clamping aperture for insertion therein during the process of setting up the retractor system.
It is against this background, and the problems and deficiencies associated therewith, that the present invention has been developed.