nitinol and Lacerations

We report the case of a 63-year-old woman who required emergent intubation after a choking episode at home. It resulted in a 5-cm tear in the membranous trachea. She was treated by placement of a temporary tracheal stent, which was successfully removed 3 months later.

Topics: Alloys; Drug-Eluting Stents; Female; Humans; Iatrogenic Disease; Lacerations; Middle Aged; Polyurethanes; Trachea

Iatrogenic tracheal laceration is a known complication of emergent endotracheal intubation. Patients with tracheal laceration present a therapeutic challenge. There is no established standard treatment approach in this patient population. Interventions reported include conservative management, stent placement, or surgery. We present our experience of tracheal tears in patients with respiratory failure successfully managed with polyurethane-covered nitinol stent, including three cases of postintubation and one case of postsurgical tracheostomy tracheal injury.

Topics: Aged; Alloys; Female; Humans; Iatrogenic Disease; Intubation, Intratracheal; Lacerations; Middle Aged; Polyurethanes; Stents; Trachea

In this study, a new nitinol based fixation device was investigated for use in repairing severed digital flexor tendons. The device, composed of superelastic nitinol, is tubular in shape with inward facing tines for gripping tissue. Its cellular structure was designed such that it has a large effective Poisson's ratio, which facilitates a “finger trap” effect. This allows for reduced tendon compression during a resting state (to permit vascular perfusion) and increased compression during loading (to drive the tines into the tissue for gripping). To test the feasibility of using this device for flexor tendon repair, it was tested on cadaver flexor digitorum profundus tendons. The tendons were excised, cut in the region corresponding to a zone II laceration, and repaired using the device. The device was easy to install and did not prevent the tendon from bending. Constant strain rate tensile testing revealed a mean tensile strength of 57.6 ± 7.7 N, with a force of 53.2 ± 7.8 N at a 2 mm gap. This exceeds the suggested primary repair strength of 45 N, which has been proposed as the necessary strength for enabling early mobilization. Although considerable future studies will be needed to determine the suitability of the new repair device for clinical use, this study demonstrates the feasibility of utilizing a tubular, nitinol repair device for flexor tendon fixation.

Topics: Alloys; Biomechanical Phenomena; Cadaver; Computer-Aided Design; Equipment Design; Equipment Failure Analysis; Feasibility Studies; Fingers; Humans; Lacerations; Materials Testing; Stress, Mechanical; Surgical Fixation Devices; Tendon Injuries; Tendons; Tensile Strength