Fraunhofer CMI Developed Artificial Hand for Minimally Invasive Surgery

News / 1.5.2015

Artificial Hand for Minimally Invasive Surgery
© Fraunhofer CMI

Artificial Hand for Minimally Invasive Surgery

Over the past several decades, minimally invasive surgery has become more prevalent because it does not require major incisions to the patient, allows for quicker healing, reduces post-operative pain, and may reduce wound complications. However, in comparison to open surgery, existing laparoscopic tools still limit the surgeon's dexterity significantly. In contrast, during open surgery or hand-assisted laparoscopic surgery, the surgeon has the ability to easily grasp, retract, and manipulate organs as necessary. Typically, the surgeon's non-dominant hand is used mainly to retract, palpate, and expose tissue, while the dominant hand manipulates instruments to conduct surgical dissection.

Laparoscopic, single incision, natural orifice and robotic approaches each hold their own appeal. However, they lack the ability to manipulate organs as easily as the human hand. Advances in minimally invasive surgical techniques require new tools with increased functionality of the end effectors. Multifunctional tools with greater dexterity than those currently available are highly desired.

To address this need, Fraunhofer CMI designed, fabricated, and tested the first prototype of a laparoscopic tool that provides the dexterity of a hand. The "hand" has two jointed fingers and a jointed thumb attached to a laparoscopic sheath that can be collapsed to fit through a 12 mm trocar or small orifice. The handle provides control for three independent degrees of freedom: finger motion (bending/spreading), finger tip bending, and thumb bending. The tool can be used for pinching, grasping, and spreading motions. Furthermore, the thumb is "double jointed" so that the tool can be converted to a rake configuration to allow lifting motions. The initial prototype has been tested in a cadaver lab to demonstrate its utility. The "Lap-Hand" was used to complete standard surgical tasks in a simulation device in a time comparable to open and laparoscopic approaches, including "bowel" manipulation and peg movement. Cadaver testing confirmed the ability to grasp, elevate and move liver, stomach, colon and small bowel in a fashion expected by the hand. During the cadaver testing, various surgeons tested the device for its ability to grasp, elevate and move liver, stomach, colon and small bowel. Three surgeons, who had not had any prior training in its use, tested the device. No adverse events were noted and no bowel injury or perforation resulted from over-grasping. Use of such tools could both reduce the number of hand-incisions required and potentially transition more patients to undergo their abdominal procedures laparoscopically.