Final Design

The design philosophy of this project is to replicate the current steps of the punch biopsy procedure and make them performable with one tool. The final design solution consisted of two main components: a pulling component and a cutting component. To operate the device, the surgeon begins by making a circular incision using the punch blade tip, identical to those used in standard punch tools. Next, with one hand stabilizing the base plate and the other gripping the top of the inner column, the surgeon simultaneously presses down the base plate and pulls upward on the tool. This coordinated motion presses down the surrounding skin while closing the tweezers on the side of the punch blade to secure the extracted tissue column. After sufficient height is pulled, the surgeon can engage the cutting mechanism on the bottom of the base plate with the hand holding it.

The main innovation in this device is the integration of the tweezers into the punch blade. Cutting the tweezer tips out of the side of the column of a typical punch blade and adding some nubs on the side of the tweezers. This makes it so that by lifting the central column that holds the punch blade, the nubs are compressed by the outer column causing the tissue sample to be compressed in the xy plane and pulled upward in the z direction. After the sample has been lifted by the tweezers the surgeon can use their pinky to actuate the blade mounted on the bottom of the tool, behind a guard. The blade is granted increased torque by the lever the pinky is touching causing the blade to pass through the tissue with little resistance.

Figure: The center column of the cutting biopsy tool and the built-in tweezers.

Figure: Bottom view of the cutting tool, with the blade positioned in the top-right corner.