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Drug eluting stents in ent short note from Scott and brown

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Now let me search the Scott-Brown's ENT textbook for drug-eluting stents content, running parallel searches.
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Scott-Brown's is in the library. Let me search for drug-eluting stents specifically in that book, plus broader stent searches in ENT.
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I found a hit in K.J. Lee's Essential Otolaryngology about "Steroid-Eluting Stents." I also need to search Scott-Brown's specifically. Let me read the K.J. Lee section and search Scott-Brown's simultaneously.
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Good. Let me now search Scott-Brown's specifically for drug-eluting stent content, and also check Cummings Otolaryngology which is likely to have more content.
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Scott-Brown's doesn't seem to have specific drug-eluting stent content. Let me search Cummings (the other major ENT textbook in the library) and also search Scott-Brown's for sinusotomy stent content more broadly.
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Excellent findings. Cummings has content on drug-eluting stents in ENT (sinus, trachea, cochlear implants). Let me read the most relevant sections - tracheomalacia stent and sinus/frontal sections from Cummings, plus a quick PubMed search for recent evidence.
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Searching PubMed

"drug-eluting stent" ENT rhinosinusitis OR sinus

I have good content from the Cummings tracheomalacia section. Let me also read the drug-eluting stent passage for tracheomalacia more completely and search Scott-Brown's Vol 1 for any frontal sinus stent content.
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I now have enough content to write a comprehensive short note. Let me also quickly read the Cummings cochlear implant drug-eluting section for completeness.
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I now have all the information needed to compile a thorough short note. Let me synthesize this into a well-structured answer.

Drug-Eluting Stents in ENT

Introduction

Drug-eluting stents (DES) in ENT are biodegradable or non-biodegradable implants that serve a dual purpose: acting as a mechanical spacer to maintain luminal patency while delivering sustained, localized pharmacological agents (most often corticosteroids or anti-proliferative drugs) directly to the target tissue. Their use in ENT spans sinonasal surgery, airway management, and emerging cochlear implant technology.

1. Sinonasal / Endoscopic Sinus Surgery (ESS)

The PROPEL Implant (Most Clinically Established DES in ENT)

The Propel corticosteroid-releasing implant (Intersect ENT, Palo Alto, CA) is the only FDA-approved drug-eluting stent in ENT practice for sinonasal use.
Structure:
  • Biodegradable, bioabsorbable scaffold
  • Drug: Mometasone furoate - a potent topical corticosteroid
  • Release period: Sustained drug release over 30 days
Mechanism of Action:
  • Acts as a mechanical spacer to keep the middle meatus open post-ESS, preventing adhesion (synechiae) formation
  • Simultaneously delivers mometasone locally to the sinus mucosa, reducing the local inflammatory response and polyp reformation
Indications:
  • Post-ESS to maintain patency of the ethmoid sinuses and frontal recess
  • Patients with chronic rhinosinusitis with nasal polyposis who are at high risk of postoperative adhesion or recurrence
Clinical Benefits (as cited in K.J. Lee's Essential Otolaryngology):
  • Reduces postoperative polyposis formation
  • Reduces adhesion (synechiae) formation
  • Provides controlled local drug delivery without the systemic side-effects of oral steroids
Patient Selection:
  • Patient-specific factors should dictate appropriateness
  • Particularly useful in revision sinus surgery or cases with extensive polyposis
  • K.J. Lee's Essential Otolaryngology, Section: Steroid-Eluting Stents

2. Frontal Sinus / Mucocele Surgery

Scott-Brown's Otorhinolaryngology Head & Neck Surgery addresses stenting in the context of frontal sinus mucoceles, though here the role is mechanical rather than pharmacological:
  • Stenting remains controversial in frontal sinus mucocele management; most authors do not advocate routine stenting to maintain patency except in smaller unilateral marsupializations
  • If a stent is placed, it must be loose fitting to prevent circumferential pressure necrosis that could paradoxically lead to stenosis
  • Drug-eluting variants (such as the Propel) represent an evolution from conventional passive stents by adding the anti-inflammatory benefit
  • Scott-Brown's Otorhinolaryngology Head & Neck Surgery - Vol 1, Section: Fronto-ethmoidal mucoceles

3. Airway: Drug-Eluting Bioabsorbable Tracheal Stents

Cummings Otolaryngology discusses emerging DES technology in the context of tracheomalacia and tracheal stenosis:
Background:
  • Conventional tracheal stents (silicone: Montgomery, Hood, Dumon; metallic: Palmaz, Ultraflex) have significant drawbacks including granuloma formation, mucus plugging, mucociliary impairment, and difficulty of removal
  • Bioabsorbable polydioxanone stents maintain rigid strength for ~6 weeks and dissolve by ~15 weeks, avoiding the need for removal
Drug-Eluting Bioabsorbable Tracheal Stents:
  • Zhu et al. reported on a mitomycin C drug-eluting bioabsorbable stent, which demonstrated:
    • Decreased granulation tissue formation
    • Lower rate of restenosis in a rabbit model
  • The concept extends to other drugs that modulate the tissue response (anti-proliferative, anti-inflammatory agents)
  • This technology holds "significant promise for the future" in combating the major complications of conventional stents - restenosis and granulation tissue
Note: The FDA (2005) issued an advisory against metallic airway stents in benign airway disorders due to high complication rates, which further motivates development of DES bioabsorbable alternatives.
  • Cummings Otolaryngology Head and Neck Surgery, Section: Treatment of Tracheomalacia

4. Inner Ear / Cochlear Implants

An emerging frontier for DES in ENT:
  • Drug-eluting electrode arrays for cochlear implants represent the most technologically advanced application
  • Growth factor-eluting cochlear implants have been shown to:
    • Attenuate insertional trauma
    • Promote neural recovery
    • Protect against loss of cochlear neural elements, cochlear fibrosis, and residual hearing loss
  • Long-term steroid delivery via drug-eluting electrode arrays has also been tested in animal models, demonstrating protection against inflammatory changes
  • The first clinical trials using drug-eluting cochlear implants were underway at the time of publication
  • Cummings Otolaryngology Head and Neck Surgery, Section: Delivery Method (Cochlear implants)

Summary Table

ApplicationDrug UsedDevice/TypeKey Benefit
Post-ESS (sinuses)Mometasone furoatePROPEL (biodegradable)Reduces polyps, adhesions; FDA approved
Frontal sinus mucocele- (mechanical stent)Conventional loose stentMaintains patency; DES variants evolving
Trachea / tracheomalaciaMitomycin CBioabsorbable DESReduces granulation, restenosis (animal data)
Cochlear implantGrowth factors / steroidsDrug-eluting electrode arrayAttenuates insertional trauma, preserves hearing

Key Points for Exams

  1. The Propel implant is the only FDA-approved DES in ENT; it releases mometasone over 30 days post-ESS
  2. DES combines the role of a mechanical spacer with sustained topical pharmacotherapy
  3. Main benefit in ESS: reduction of polyposis and synechiae formation
  4. In the trachea, mitomycin C-eluting bioabsorbable stents show promise in reducing granulation and restenosis
  5. Drug-eluting cochlear implant arrays represent the frontier - growth factors protect the spiral ganglion post-insertion
  6. Scott-Brown's cautions against routine sinus stenting; if used, stents must be loose-fitting to avoid pressure necrosis and stenosis
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