Surgical Stapler Inserts With Spline Covers to Prevent Spline Crash

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Solution Overview

Problem

Circular stapling devices experience spline crash and binding issues due to improper alignment of anvil and shell assemblies, leading to damage and malformation of staples during firing.

Innovation Solution

Incorporation of inserts and spline covers within the shell assembly to align anvil and shell assemblies, using metal spline covers and plastic splines to minimize damage and prevent spline crash.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional spline alignment structures are used in circular stapling devices, then the device complexity is reduced, but spline crash and binding occur leading to damage of anvil and shell assemblies

Engineering Contradiction:

Improvealignment reliabilityVSAvoidalignment structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces inserts with spline covers as intermediary components between the anvil assembly and shell assembly. These spline covers act as protective mediators that prevent direct contact and potential crash between the splines, while still allowing proper alignment through camming surfaces and guide features.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The spline covers are installed beforehand on the inserts to provide protective cushioning before any potential spline crash can occur. This preventive measure ensures that even if misalignment occurs during assembly, the soft spline covers will absorb the impact and prevent damage to the hard spline surfaces.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Object-affected harmful factors

If spline covers are added to protect against spline crash, then damage to assemblies is minimized, but the device complexity increases

Engineering Contradiction:

Improvespline damageVSAvoidassembly structure complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The spline covers are designed with asymmetric geometry where the leading edge is softer and more compliant than the trailing edge. This asymmetric design allows the leading edge to absorb impact forces during potential crash scenarios while maintaining proper alignment geometry throughout the rest of the spline interface.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The inserts combine multiple materials with different properties - the body may be made of rigid material for structural support while the spline covers are made of softer, more compliant material for protection. This composite approach provides both the strength needed for alignment and the cushioning needed to prevent damage.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS12433596B2Inserts, splines, and methods for reducing and/or eliminating spline crash in surgical instruments

Publication Date: 2025.10.07 COVIDIEN LP

AI summary

Inserts and features to reduce or prevent spline crash in surgical staplers and/or to minimize damage resulting from spline crash in surgical staplers. An insert for a surgical stapler includes a body and spline covers. The body is configured to fit within a bore of a shell assembly and the spline covers extend inward from the body. Each of the spline covers are sized and dimensioned to cap a distal portion of splines of the shell assembly. A shell assembly for a surgical stapler includes shell splines that are disposed on an inner wall of an inner housing portion that defines a bore. The shell splines include a lead spline that has a leading end positioned distal of a leading end of each of the other shell splines.