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Lacrimal stenting systems have been used to maintain patency of the canaliculi after insults such as surgery, trauma, radiation, and chemotherapy. The first nasolacrimal stents were made of silver wire and used by Graue in 1932.
Since then, other materials have been used, including silk, nylon, polyethylene, and polypropylene. Modern-day stents are most commonly made of silicone because this material is pliable, affordable, and widely available. Previously thought to be inert, there is evidence that silicone can elicit a foreign-body and inflammatory reaction.
While such reactions have been reported for other medical devices, it has not been discussed in the case of lacrimal intubation apparatuses. The purpose of this report is to describe a case of allergic conjunctivitis and contact dermatitis following endoscopic dacryocystorhinostomy (DCR) with silicone intubation. The collection and evaluation of protected patient health information were compliant with the Health Insurance Portability and Accountability Act of 1996.
Case Presentation
A 74-year-old female blepharitis, Hashimoto's disease, and calcium pyrophosphate deposition disease presented with left-sided nasolacrimal duct obstruction. She underwent uneventful left DCR with silicone tube intubation. In the early postoperative period, she developed a significant left-sided papillary reaction, conjunctival injection, and irritation 29 days after initial surgery (Fig. 1A). The inflammatory reaction completely resolved after the tube was removed 45 days postoperatively (Fig. 1B). More recently, the patient underwent ambulatory cardiac monitoring and had a silicone adhesive patch applied. In this region, she developed an erythematous rash that also completely resolved following removal of the adhesive patch (Fig. 2). She has done well from a lacrimal perspective and remains asymptomatic 4 months after DCR.
Fig. 1(A) Left-sided papillary reaction and conjunctival irritation 29 days after initial surgery (B) Resolution of inflammatory reaction after tube removal 45 days post-operatively.
This case demonstrates contact allergy to silicone lacrimal tubes following endoscopic DCR. Features suggestive of a contact allergy include delayed presentation, unilateral periocular reaction, and similar inflammatory reaction on her chest from another silicone-based product.
Foreign-body and inflammatory reactions to silicone have been described in the systemic literature widely. For instance, following breast augmentation, foreign-body reaction to silicone can result in capsular fibrosis, and coatings that decrease this inflammatory reaction are under investigation.
Inflammatory reactions to silicone have been implicated as a cause of cochlear implant extrusion and may be a rare cause of ventriculoperitoneal shunt failure.
In contrast, allergic contact dermatitis to silicone is rare and limited to case reports. Medical devices with documented cases of silicone allergy include breast prostheses, pacemaker coatings, tracheal tubes, cochlear implants, dialysis catheters, and continuous positive airway pressure masks.
Many allergies are type I hypersensitivity reactions, characterized by rapid overproduction of IgE in response to a particular antigen. Type IV hypersensitivity reactions represent a slower, cell-mediated response to an antigen. While some studies have found increased levels of IgE and silicone antibodies in patients following insertion of a silicone implant, others have concluded that reactions to silicone are more in keeping with nonspecific foreign-body reactions.
In addition to a direct immunogenic response to silicone, another potential etiology of inflammation is the components used in manufacturing, such as the chemicals for fixing additives and product sterilization.
Contact allergy to allyl glycidyl ether present as an impurity in 3-glycidyloxypropyltrimethoxysilane, a fixing additive in silicone and polyurethane resins.
Postoperative histopathologic changes in lower nasolacrimal duct mucosa following silicone intubation have been studied in rabbits, and these authors concluded that longer intubation times were associated with increased transforming growth factor beta 1 activity, granuloma formation, progressive fibrosis, and adhesion of surrounding tissues.
Though there are no prior reports of contact allergy to silicone in the setting of lacrimal system intubation, when considered with the case presented here, these prior studies are suggestive of the immunogenic activity of silicone lacrimal tubes.
While intubation is commonly performed in DCR surgery, the necessity of this step has been debated in the literature.
Although the high success rate of routine DCR surgery makes it challenging to identify small improvements in outcomes attributable to silicone intubation, the case presented herein emphasizes that silicone intubation may not be a completely benign procedure. It may be so that in certain cases silicone intubation may positively affect outcome, but in others the opposite may be the case.
Footnotes and Disclosure
None of the authors have any financial disclosures or conflicts of interest to report, and no financial assistance was received in support of this research.
Supported by: This work is supported by an unrestricted grant from Research to Prevent Blindness, Inc., to the Department of Ophthalmology at UCLA.
References
Singh M. Lacrimal stents and intubation systems: An insight. Delhi J Ophthalmol 2015;26:14-19.
Contact allergy to allyl glycidyl ether present as an impurity in 3-glycidyloxypropyltrimethoxysilane, a fixing additive in silicone and polyurethane resins.
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