Artificial hand for minimally invasive surgery: design and testing of initial prototype.

Background: Compared with traditional open surgery, minimally invasive surgery may improve recovery and patient satisfaction while maintaining surgical principles. Laparoscopic, single incision, natural orifice, and robotic approaches 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.

Methods: To address this need, we 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), fingertip 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.

Results: Our "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. No adverse events were noted, and no bowel injury or perforation resulted from over-grasping.

Conclusions: We have designed, built, and tested a first prototype of an artificial hand for minimally invasive surgery. Use of such tools could both reduce the number of hand-incisions required and potentially transition more patients to undergo their abdominal procedures laparoscopically.