For example, the nitinol U-clip™ (Medtronic ® ) has been used effectively to secure annuloplasty bands in minimally invasive mitral valve repair, but cannot be used for leaflet repair. Suture-free alternatives such as staples, clips and glues have proven effective in certain procedures but can have limited applicability. Devices include the Autosuture™ Endo Stitch (Covidien, Mansfield, MA, USA), the Suture Assist (Ethicon Endo-Surgery, Cincinnati, OH, USA), and a Suture Cartridge as well as others. To address this need, various laparoscopic instruments have been developed to automate the knot-tying process or deploy pre-tied sliding knots. Furthermore, older patients and otherwise ‘unhealthy’ patients make up a majority of the candidates requiring surgical procedures. This leads to the double bind between the ‘need for speed’, which the direct access and visibility of traditional ‘open heart’ procedures allow, and the requirement that the MIS patient be comparatively ‘young and healthy’ to survive the increased CPB times required for MIS. Patient mortality rates increase with the time during which the heart is arrested, especially in the case of older patients. Increased CPB times lead to higher risks of multiple organ dysfunction syndrome (MODS), and procedures involving CPB are linked to adverse cerebral outcomes, including strokes, transient ischaemic attacks and seizures.
Operating time can be especially critical for cardiac procedures involving cardiopulmonary bypass (CPB).
The crux of the problem as it relates to MIS is that knot tying with traditional suture materials using laparoscopic or robot-assisted tools can lead to increased operation times. The clinical effectiveness of MIS frequently depends on the surgeon’s suturing skills, however, and knot tying with conventional laparoscopic tools can be challenging. Sutures remain the ‘gold standard’ of fixation for many surgical fields, as the visual and haptic feedback associated with suture tensioning are critical means by which the surgeon assesses good tissue apposition. The challenge of intracorporeal suturing and knot tying, at awkward angles and with limited visibility and depth perception, has long been recognised as a significant barrier to the advancement of minimally invasive surgery (MIS). Conclusions: Experimental data reveal that the automated suturing device has great potential for advancing minimally invasive surgery: it significantly reduced knot-tying times while providing equivalent or greater holding strength than conventionally tied knots.Īutomated suturing, Knot tying, Fixation, Minimally invasive surgery 1 Introduction Mean normalised holding strengths for all knots were 68.2% and 71.8% of ultimate tensile strength for conventional and automated methods, respectively ( p = 0.914, paired t-test). These peak holding strengths were normalised by the ultimate tensile strength of each suture type (57.5 N and 22.1 N for 2/0 braided and 4/0 monofilament, respectively). The peak holding strength of each knot (the force required to break the suture or loosen the knot) was measured using tensile-testing equipment. Results: Mean knot-tying times were 246 ± 116 s and 102 ± 46 s for conventional and automated methods, respectively, showing an average 56% reduction in time per surgeon ( p = 0.003, paired t-test). Suture types were 2/0 braided and 4/0 monofilament. Methods: To evaluate the effectiveness of this technology, seven surgeons with varying laparoscopic experience tied knots within a simulated minimally invasive setting, using both the automated knot-tying tool and conventional laparoscopic tools. The electronic actuation of this disc produces left or right overhand knots as desired by the operator. A rotating slotted disc (at the instrument’s distal end) automates overhand throws, thereby eliminating the need to manually pass one suture end through a loop in the opposing end. An automated knot-tying device has been developed to speed suture fixation during minimally invasive cardiac surgery while retaining the desirable characteristics of conventional hand-tied surgeon’s knots: holding strength and visual and haptic feedback.
Objective: Intracorporeal suturing and knot tying can complicate, prolong or preclude minimally invasive surgical procedures, reducing their advantages over conventional approaches.