Suturing End-Effector with Foldable Needle and Direct Actuation
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Solution Overview
Problem
Current endoscopic suturing instruments face challenges such as large diameter, unreliable force and motion transmission, limited dexterity, and difficulty in delivering tools through endoscope channels due to their design, which hinders efficient closure of gastrointestinal tract defects.
Innovation Solution
A suturing end-effector with a dual-mode design that allows for a smaller transportation mode to navigate through endoscope channels and a larger suturing mode for defect closure, featuring a flexible tendon-sheath mechanism for articulation and a hollow suture needle with a guide wire for alignment, enabling triangulation and efficient stitching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the suturing needle is always standing erected in between the two jaws, then the needle can be easily accessed and locked, but the outer diameter of the instrument becomes too large to be delivered through the endoscope channel
Solution Approach 1:
The needle is designed to be dynamically reconfigurable between an erected position during suturing operations and a folded/stowed position during delivery. The needle can be rotated about its longitudinal axis and folded back against itself, allowing the instrument diameter to be reduced for passage through the endoscope channel while maintaining full needle length and functionality when deployed at the surgical site
Solution Approach 2:
The needle is configured to nest within itself when folded, with the distal portion of the needle containing the eye positioned inside the proximal portion of the needle. This self-nesting arrangement minimizes the overall instrument diameter during delivery while preserving the complete needle structure for suturing operations
2Device complexity
If torsion transmission is used to translate locking blades along the longitudinal axis, then the mechanism can be compact, but the transmission is unreliable in tortuous GI tract paths
Solution Approach 1:
The patent replaces the torsion-based camming mechanism with a direct longitudinal translation system. The locking blades are moved along the longitudinal axis of the instrument through direct mechanical coupling to the actuation shaft, eliminating the need for torsion transmission through flexible shafts and camming mechanisms. This substitution provides more reliable force transmission through the tortuous GI tract path while maintaining a compact device structure
Solution Approach 2:
The complex torsion-to-translation camming mechanism is extracted and replaced with a simpler direct translation system. The locking blades are directly coupled to the actuation shaft for longitudinal movement, removing the intermediate camming hub and torsion transmission elements that caused reliability issues in previous designs
3Device complexity
If the instrument is steered with only two cables, then the structure remains simple, but the instrument can only steer in one plane, limiting dexterity
Solution Approach 1:
The steering system is segmented into multiple independent cable systems, each controlling different degrees of freedom. In addition to the two cables for planar steering, additional cables are provided to control articulation and triangulation movements, enabling the instrument to steer in multiple planes and achieve complex positioning at the surgical site while maintaining a relatively simple modular cable architecture
4Device complexity
If the flexible shaft is pushed to open the jaws, then the mechanism can be simple, but the jaws may be difficult to open when the shaft cannot transfer pushing force effectively
Solution Approach 1:
Instead of pushing the flexible shaft to open the jaws, the system uses pulling forces on the flexible shaft to close the jaws. The flexible shaft is configured to transmit tensile forces effectively, and the jaw actuation mechanism is designed so that pulling the shaft distal end causes the jaws to close through the mechanical coupling, while jaw opening is achieved by releasing the tension or using a separate mechanism
Data Source
Figure 1A~1b
Figure 1C~1D
Figure 2A~2D
AI summary
A suturing end-effector comprising a jaw assembly, including a first jaw having a through-hole, and a second jaw having a through-hole. The jaws are openable and closeable relative to each other. The suturing end-effector may further include a hollow suture needle having a first pointed tip, a second pointed tip and an inner channel. In a stowed disposition, the needle is clamped flat between the jaws, and a guide wire runs through the through-hole of the first jaw, the inner channel of the needle, and the through-hole of the second jaw, such that opening the jaws and tensioning the guide wire align the needle with the first pointed tip directed towards the through-hole of the first jaw and the second pointed tip directed towards the through-hole of the second jaw. Also disclosed is a tendon and pulley mechanism configured to alternately lock a suture needle to the first and the second jaw.