A Specimen Extraction Instrument Based on Braided Fiber Tube for Natural Orifice Translumenal Endoscopic Surgery

Abstract

Natural orifice translumenal endoscopic surgery (NOTES) has offered significant advantages of less pain, reduced recovery time, and minimized scar after operation, demonstrating a promising development prospect. However, the large-size specimen extraction remains challenging for NOTES, due to the narrow space of the human natural orifices. To address such difficulties, a specimen extraction method that utilizes the braided fiber tube (BFT) structure with excellent retractility to accommodate and bind the bulky specimen has been proposed. Based on the theory of helical spring, the geometric model and the mechanical model of the BFT are established, and experiments have been performed to verify the accuracy of the derived mechanical model. In addition, a tensile test of using the BFT to extract large specimens via a small channel is carried out, which verifies the stable extraction performance of the proposed design. The BFT will not be damaged when extracting the specimen with a diameter less than 1.75 times of the channel diameter. A NOTES-specific specimen extraction instrument is designed according to the characteristics of NOTES, and it has three degrees-of-freedom and is able to actively capture different specimen by using a suction cup. Finally, specimen extraction experiments on NOTES multitasking platform phantom have been conducted using the prototyped instrument to validate its feasibility and effectiveness.