Variable Stiffness Cannula for Ophthalmic Surgery
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Solution Overview
Problem
Conventional soft-tipped cannulas are insufficiently rigid to effectively open valved cannulas, requiring additional instruments for insertion, which can cause trauma to the incision site during ophthalmic procedures.
Innovation Solution
A microsurgical instrument with a distal tip that transitions between a rigid and less rigid configuration in response to temperature changes, allowing independent insertion through a valved cannula while maintaining surgical functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a soft-tipped cannula is used to minimize injury to delicate eye tissues, then safety is improved, but the cannula becomes insufficiently rigid to effectively open valved cannulas
Solution Approach 1:
The cannula incorporates a shape memory alloy distal tip that can dynamically change its mechanical properties between rigid and soft states through temperature control, allowing it to be rigid during insertion and soft during tissue manipulation
Solution Approach 2:
The distal tip's temperature is controlled to change its physical state - cooled to room temperature or below for rigid insertion, then warmed to body temperature or above for soft tissue manipulation, directly changing the rigidity parameter
2Ease of operation
If a more rigid instrument is used to open the valved cannula slit, then ease of operation is improved, but the risk of trauma to the incision site increases
Solution Approach 1:
The cannula's distal tip transitions from a soft state during insertion (minimizing trauma) to a rigid state when needed for opening the valved cannula, dynamically adapting its properties to the operational requirement
Solution Approach 2:
Temperature control enables the distal tip to switch between soft and rigid states, allowing the same instrument to perform both gentle insertion and forceful slit opening without causing trauma
3Device complexity
If a single instrument is used for both insertion and tissue manipulation, then device complexity is reduced, but the instrument must accommodate conflicting mechanical requirements
Solution Approach 1:
The cannula is designed as a multi-functional instrument where the distal tip can serve dual purposes - acting as a rigid opening tool for the valved cannula and a soft manipulation tool for delicate eye tissues, eliminating the need for separate instruments
Solution Approach 2:
The variable stiffness capability allows the single instrument to adapt its mechanical properties to different operational phases, providing both rigid and soft functionality within one device
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables efficient and safe manipulation of delicate eye tissues by maintaining rigidity for insertion and flexibility for tissue manipulation within the eye, reducing the risk of injury during ophthalmic procedures.
Implementation Method 1
the distal tip is configured to transition between a first rigid orientation and a second less rigid orientation
Data Source
AI summary
Described herein is an apparatus for treatment of an ocular condition of a patient, comprising a hollow elongate member sized to penetrate an eye of the patient and including a body portion, a distal tip, and a lumen extending though both. The body portion includes a proximal end, a distal end, and a first diameter, and defines longitudinal axis. The distal tip extends from the distal end of the body portion and is arranged to treat tissue in the eye. The distal tip includes an inner tube defining the lumen in part, an outer sheath surrounding the inner tube, and a second diameter. The distal tip is configured to transition between a first rigid orientation and a second less rigid orientation.