Biopsy with Side-Cutting Coaxial Needle-Knowing the "Cutting Length" and "Throw Length"

Image-guided Trucut biopsy is a well-established procedure. The length of the side notch in the stylet is the "cutting length," which entraps the tissue sample and contributes to the yield. The total distance by which the inner stylet protrudes from the outer cannula with the cutting notch open is the "throw length." It is inevitably longer than the cutting length does not add to the yield of the sample, but potentially to the complication of the procedure. The authors highlight the importance of knowing this distinction to minimize complications during the procedure.