Small in Size, Big on Precision

Belden Inc., manufacturer of universal joints, has developed a miniaturized universal joint for a surgical tool used in minimally invasive surgery. The surgical manual manipulator system required a joint to transmit the power from the handle to the connecting shaft.

Tuebingen Scientific Medical GmbH, a spin-off company of the University of Tübingen, Germany, is a medical device company specializing in instrumentation for minimally invasive surgery. The surgical systems fill in the gap between conventional surgical instruments and surgical robotics. While conventional instrumentation does not meet the requirements of advanced endoscopic surgeons, robotic systems are too complex and costly for daily routine use. Tuebingen's manual manipulator system, called Radius Surgical System, combines the best of both worlds, representing a new class of surgical devices entirely focused on providing full operating freedom and optimal ergonomics without the complexity of electromechanical robotic devices. The surgical system has been designed to improve endoscopic suturing and other surgical maneuvers, and can also be used for a wide variety of surgical procedures in different clinical specialties.

The surgical system consists of two hand-guided surgical manipulators. Depending on the task, graspers, scissors, needle holders and other devices can be attached to the tip; changeover only takes a few seconds. The system required a universal joint to transmit the power from the handle, which acts as a natural extension that emulates the movement of the hand to the connecting shaft. The joint itself has an outside diameter of 8mm (0.315 in.) to accommodate the space limitations of the surgical tool. A deflectable and rotateable tip provides all degrees of handling freedom.

During design development, the customer requested a specialized hub configuration to ensure a secure connection and precise operation. By means of innovative manufacturing processes, Belden made modifications to the standard universal joint concept and delivered prototypes for testing. The final design now incorporates the universal joint and a component of the internal extension as a single piece, which Radius Surgical System's two hand-guided manipulators. Small in Size, Big on Precision Edited by: Kelsey Higginbotham was originally two separate pieces. Adhering to the sterilization regulations required by the medical industry, the universal joint is manufactured in stainless steel.

With the small OD, Belden's miniature universal joints are suitable not only for medical equipment, but also for many other applications in which space is restricted, including miniature machinery and model making. Originally developed in stainless steel for the manual operating device, Belden's miniature joints are also available in alloy steel, with or without plating, and in a variety of stainless steel grades to fit any application.