Stent Lock Mechanism for Transcutaneous Catheters

DESCRIPTION (provided by applicant): Peritoneal dialysis, intravascular access for chemotherapy, transcutaneous intrathoracic access of cardiac power lines, and suprapubic bladder drainage are among the clinical applications where transcutaneous catheters are routinely used in the course of treatment. Although these devices perform well for short durations, effective long-term use is limited. Traditional transcutaneous catheters are not watertight, and these open ecosystems permit skin microbes to migrate along the catheter into the body. Advances in peritoneal dialysis catheters attempt to close the open ecosystem with the implantation of a porous alloplastic component of the catheter into the body wall. However, should infection occur along the catheter or within the peritoneum, surgery is required to remove and replace the catheter. A similar, but significantly different investigational approach has been implemented for suprapubic drainage of the urinary bladder. This tissue-bonded cystostomy (TBC) is one clinical example of the need for a secure, reversible locking mechanism that will create a robust, watertight, reversible lock between an ingrown anchor component and the transcutaneous drainage tube that passes through the anchor into the urinary bladder. The same principle extends beyond urinary drainage to peritoneal dialysis, chronic vascular access, and chronic intrathoracic access. Proof of concept of a robust, reliable, easily reversible, watertight locking mechanism is the first step in development of a transcutaneous access device with broad medical applications. Accordingly, an innovative design is proposed for a Stent Lock mechanism that uses a shape-memory-alloy wire with unique properties ideally suited to provide a secure, reversible lock. Instead of a mechanical interference fit, the mechanism uses high friction force to hold the catheter firmly in place. Since it is totally enclosed within the walls of the drainage catheter, no part is exposed to the surrounding tissue or fluid environment. This Stent Lock mechanism will be developed in Phase I for proof of concept in a suprapubic TBC urinary implant. An existing anchor element will be modified, and two tools developed to lock and unlock the catheter in the anchor. The magnitude of friction forces will be experimentally evaluated along with the pullout force necessary to remove the locked and unlocked catheter from the anchor. Success in Phase I will lead to animal studies in Phase II and modification of the concept for other transcutaneous access applications.