The development of a novel method of hysteroscopic sterilisation

For over 100 years gynaecologists have attempted to effect sterilisation via a transcervical approach, however most had limited success. Our aim was to develop a safe and simple method of hysteroscopic sterilisation, which could be performed as an out-patient. A tubal device based on a self tapping screw was developed as it was felt that such a design would be less likely to become dislodged with time. In-vivo and in-vitro application studies were performed to ensure correct positioning of the screw at the tubal ostia and to test the strength of application. The equipment used to apply the tubal screw initially consisted of a modified hysteroscope, superseded by a cystoscope; the original application technique used a tubular cannula and 'push-rod' for screw disimpaction, this was replaced by mounting the screw with a titanium bayonet loosely in a metal coil applicator. The means of providing effective uterine distension evolved from the use of fixed and variable flow hysteromat pumps to the use of a large pressure bag to provide for excellent cornual visualisation. In women undergoing concurrent laparoscopic sterilisation tubal patency was tested pre and post screw application and to monitor screw retention interval pelvic ultrasonography was performed. If the tubal screws were still present after 1 year they were removed hysteroscopically under local anaesthesia. The development of the equipment was challenging requiring many changes to improve the screw application technique; this was manifested in an improvement of screw retention with the final apparatus. In-vitro and in-vivo screw application demonstrated that the screws were held firmly at the uterine cornu. However, despite demonstrating effective tubal occlusion with the tubal screws, in-vivo screw retention even in the later stages of the development process was poor. Further refinements of the equipment are essential prior to testing as a method of sterilisation