All posts by Paul Breedveld

Endo-Periscope I – Compliant yet Torsion Stiff

Developed in 1999-2000, diameter 15 mm, steering range: up/down 0º-180º, left/right ±60º

The Endo-Periscope I has been developed in cooperation with Prof. Shigeo Hirose of the Hirose & Fukushima Laboratory, Tokyo Institute of Technology.

Endo-Periscope I is a patented steerable endoscope for laparoscopic surgery containing a novel, torsion-stiff “Ring-Spring”. The compliant Ring-Spring consists of a number of spring-metal rings that are bent and welded to each other in pairs. The rings contain holes for guiding steering cables. The Ring-Spring is controlled by a novel spatial parallelogram-mechanism that unfolds the spring from a compressed position to minimize bending radius of the steerable tip. The tip has always the same orientation as the hand grip, offering intuitive control to the surgeon showing how the tip is oriented in the abdominal cavity. The Ring-Spring is only used to control up/down tip rotations. Left/right tip rotations are controlled by a conventional hinge-mechanism.




Steerability – How it all started…

During Minimally Invasive Surgery (MIS) surgical instruments and an endoscopic camera are inserted  through tiny  incisions into the human body. This approach reduces the patient’s recovery time, the size of the scars and the risk of complications. Unfortunately, MIS also has its drawbacks since the intervention becomes more difficult for the surgeon:

  • There is limited visual 3D information (and thus no proper depth perception) of the surgical area.
  • The surgeon’s eye-hand coordination is distorted because the camera looks at the organ from a different angle than the surgeon would normally do.
  • The motion of rigid instruments is strongly limited by the fixed position of the incisions.
  • The surgeon’s ergonomic position deteriorates due to the use of  long and rigid instruments in combination with fixed incision points.

One way to obtain more depth information is to enable motion parallax – obtaining depth information by mutual displacements of objects in the field of view when moving the eye while keeping the viewpoint in focus. With conventional rigid endoscopes, however, moving the endoscope results in the viewpoint to shift away as the endoscope rotates around its incision point.

During his stay in the Hirose & Fukushima Laboratory, Tokyo Institute of Technology, Paul Breedveld and Shigeo Hirose developed an endoscope with a steerable parallelogram mechanism, enabling motion parallax and facilitating eye-hand coordination. This resulted in the first steerable endoscope of the BITE-Group – the Endo-Periscope I.