Applications of Shape Memory Polymers in Surgery

 

Author: LIU Na
Last Update: 6 Oct 2006

 

PROJECT DESCRIPTION:

Overview

All humans have limitations in manual positioning accuracy due to involuntary tremor movements. In surgery like eye surgery, high accuracy is desired and high tremor is intolerable. As the surgeons get older, their noise signals get larger and their tremor motion increase. This forces the surgeons to retire at a relatively young age. With the high cost in training new surgeons, high demand for experience surgeons and insufficient of qualified surgeons, it is beneficial to come out with an instrument that is able to sense and compensate the erroneous tremor motion.

 

Introduction

In line with minimally invasive surgery, a novel suturing thread is being developed to meet the needs of advancements in surgical procedures.

 

Motivation

Advancements in medical robotics enable miniature robotic manipulators to be inserted into the human body non-invasively or minimally invasively to perform therapeutic intervention. Due to the small size of these manipulators, their pay loads are also drastically reduced. Future in-body robotic manipulators may not be able to generate enough forces to tie a suture properly.

 

Objective

To develop a novel suturing thread that would untie or tie itself into a knot autonomously. The outcome of this project would be used in conjunction with other ongoing medical robotics project to enable miniature robotic manipulators to be inserted into the human body non-invasively or minimally invasively to perform therapeutic intervention.

 

Shape Memory Polymer

It is well-known that shape memory polymers (SMPs) are able to recover a substantial amount of pre-strain (> 300%) upon heating. This is much higher than that of shape memory alloys (about 7% recoverable strain).

Currently, we are working on a SMP which can be actuated by room temperature water and can recover following a pre-determined sequence, i.e., the actuation of the SMP is programmable (Figure 1).

 

 

Bio-Devices using SMP

Since this particular SMP is biocompatible, utilizing the findings, many novel bio-devices can be easily realized for surgery applications. For example, self-unraveling knot as shown in Figure 2, self-tightened suture in Figure 3, and retractable stent in Figure 4.

 

 

 

References
[1] Huang et al. Appl Phys Lett, 2005 86 114105.

 

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