Nitinol Laryngeal Stent
DexStent-LN is a newly developed implantable stent system for the treatment of Vocal Fold or Laryngeal Paralysis. It is composed of a very uniquely shaped Nitinol stent and comes in a variety of sizes with a separately packaged stent delivery system. The stents are shape-set and exhibit superelasticity. The device is self-expanding and when compressed will return to the shape set. The device is implanted distal to the vocal folds. The pads of the Y-lock part of the stent apply outward pressure to the vocal folds. Therefore the stent acts as a self-expanding device. It does not touch the vocal cords and allows the adductor muscles to close the larynx. The stent is radiopaque for high visibility during Xray imaging or fluoroscopy, assuring precise stent positioning and MRI compatibility. DexStent-LN is patent protected under US9532889B2, EP3107491B1.
Relieve patients from breathing difficulties
Vocal fold paralysis (VFP) – full or partial vocal fold closure occurs in humans and animals (dogs and horses). The primary objective of the stent is to relieve patients of their difficulty in breathing. Vocal Fold Paralysis can have many causes:
- Laryngeal or extalaryngeal cancers
- Post surgical nerve and muscle injury (e.g. thyroid surgery)
- Externally-induced physical trauma
- Presbylarynx – a condition of age-related atrophy of larynx
- Vocal fold paresis – weakness of one or both of the vocal folds
- Vocal fold plegia – all voluntary movement of vocal folds is lost
- Post radiation nerve and muscle damage
The new DexStent-LN device is intended to be used as an alternative to the following procedures:
- Tracheostomy – incision into the larynx
- Artenoidectomy – removal of arytenoid cartilage enlarging the airway
- Cordotomy – enlarging the airway by removal of vocal fold tissue
- Laterofixation – surgical suture used to lateralize the vocal fold (tie-back)
DexStent-LN device will focus on the following field of use:
- Laryngeal paralysis is one of the more common upper respiratory emergencies seen in our aging canine population
- Typically 8+ year old dogs
- Medium to large breeds
- Smaller device sizes for small dog breeds are currently in development
- Estimated to be ~5,000 cases per year in the US
How does the stent work?
- DexStent-LN is designed to be placed subglottically.
- There are three pads on the crown loop of the device. The anterior pad sits just below the anterior commissure which is a very benign area, so it will not cause an adverse reaction.
- The two lateral pads touch the inferior aspect of the vocal folds to create the opening.
- The stent will create an opening but it is not as dramatic as the tieback and it is more centralized.
- Because of the memory-shape set characteristics of the super-elastic Nitinol alloy, the stents wants to stay in an expanded shape creating an opening in the vocal folds.
- It keeps the vocal cords open enough so the dog breathes comfortably and yet when the dog swallows, coughs or barks it squeezes the stent sufficiently, therefore allowing the vocal folds to close the larynx which is what reduces or eliminates the incidence of aspiration pneumonia.
- The goal is to gently assist the vocal folds with the opening ability they have lost.
Nitinol Laryngeal Stent implantation procedure
Implantation Procedure in Less Than a Minute!
Delivery system and stents are available in a variety of lengths designed by us for use in dogs. The delivery system is optimized for precise handling and accurate stent placement via bronchoscope. The delivery system can be re-sterilized and reused. After stent placement, the stent can be re-positioned or removed and then re-implanted via the tools included. Stent layout and configuration shows excellent bending flexibility and keeps its shape even when forced into the tight delivery cup and does not kink.
This is a very new type of medical device with a novel way of stent delivery and application. New users must be properly trained and caution is advised.
Several rounds of animal safety and performance studies have been completed since the original development took place in 2012 with 2, 6 and 7 stent placements. Nine of them were performed as part of a good lab practice study for the FDA. None of the 15 animals showed any evidence of aspiration pneumonia and most of the dogs were observed for almost a year. They were examined several times throughout that year. NYU- Prof. Robert Ward, the co-inventor of the device, observed that the stent placement is typically a rather quick endoscopic procedure with much less morbidity than the tieback procedure. Current (unconfirmed) data indicate that up to 50% of dogs with a unilateral tie back will have some episodes of aspiration pneumonia, which is not a risk with DexStent-LN but elimination of that risk due to the unique way the super-elastic stent is functioning.
Since the original studies took place, the stent has been mechanically reinforced by us against the risk of stent fracture and the stent Nitinol materials and delivery system have been redesigned and improved for longterm reliability. Initial implantation in canine patients with laryngeal paralysis show promising outcomes, but the number of implantations is so far relatively small and caution is advised. We will update this page when newer and better information becomes available.
Nitinol Laryngeal Stent Size Comparison
|18||Large Pugs, Bulldogs|