Introduction
Voice prosthesis is the gold standard for post-laryngectomy voice rehabilitation. Surgical treatment and tracheo-esophageal (TE) puncture performed simultaneously is the best option [1]. In the post operative early speech therapy is necessary to voice restoration/rehabilitation. In these patients optimal results can be achieved, they can reach a better maximum phonation time, compared to those ones using esophageal speech and some of them are able to use hands-free tracheostoma breathing valve (Hakeem 2010). Voice prosthesis hygiene can be performed at home by the patients simply using a dedicated brush, nevertheless periodically replacement is required, usually by an ENT specialist, because of malfunctions, extrusion, common wall swelling, gastric filling [2, 3]. The main cause of malfunction is due to leakage phenomenon that consists in the passage of saliva, liquids or, sometimes even bolus through the device, passing from the esophagus to the lower airways. Leakage can be classified in intraprosthetic and periprosthetic. The first one is the most common cause of prosthesis malfunctioning (80% of all cases) and is caused by a disfunction of the silicone elements of the esophageal flange result of mycotic and bacterial biofilm colonization of the latter [4–6] even though prostheses are made of medical grade elastomers such as silicone or polyurethane, in order to reduce microbial colonization. Periprosthetic leakage takes place in case of an enlargement of the tracheo-esophageal fistula and it occurs in 20–30% of all patients with voice prostheses over time [7]. Prosthesis’ smooth silicone surface in fact can be deteriorated by free radicals and extracellular enzymes produced by yeasts and bacteria, adjuvanted by proinflammatory enzymes, cytokines and several catabolites produced by the immune system [8].
In previous study we described biofilm colonization on voice prosthesis and the related effect on medical silicone using sonication and microscopy analysis at SEM [6].
In recent literature in dental medicine a “Guided Biofilm Therapy” is employed to prevent periodontal disease related to dental and gingival biofilm colonization. It uses advanced tools to get rid of biofilm or bacterial deposits on the surfaces of the teeth: The bacterial biofilm can be clearly visualized by using a disclosing agent, a non-toxic substance, which aids in its complete removal [9].
In this short communication we describe a new method to reveal biofilm colonization on voice prostheses, using an easy dye, already used in the “guided biofilm therapy”, in order to detect biofouling specific sites and facilitating brushing during daily prosthesis cleaning.
Discussion In the present rapid communication we describe the application of erythrosine dye for voice prostheses and the direct visualization of biofilm colonization sites. We collected 20 voice prostheses removed from laryngectomized patient after a period between 2 and 12 months of use even though the valve was still functioning to show the distribution of biofilm before the malfunction (Fig. 1).
Fig. 1.
A Voice prosthesis after dye, presented a diffuse blue coloring. B Voice prosthesis after dye, presented a light rose coloring. C Biofilm deconstruction of silicone in worn-out voice prosthesis
The prostheses have been replaced anyway during a follow-up ORL examination, because of: perifistular granulations, fistula’s enlargement or spontaneous extrusion, the patients did not have any respiratory distress or evidence of intraprosthetic leakage. The removed prostheses have been washed in saline solution and stained with a biofilm discloser composed by a solution of erythrosine (CI 45430) and patent blue (CI 42051). Subsequently they have been rinsed in saline solution and dried in ambient air. Erythrosine and patent blue are dyes used in dental medicine to highlight dental plaque, known to consist predominantly of bacterial biofilms. The red staining is able to highlight thin slices of biofilm of recent growth. Patent blue can highlight mature mushroom shaped biofilm.
After staining the prostheses had different colorations. Some of them some had a widespread blue coloring, demonstrating the presence of mature biofilms. While the others presented a light rose coloring, as per presence of young biofilms. One of the prosthesis (Panel C) due to its normal functionality but complete colonization of the esophageal flange, was dissected and observed by optical microscope Leica (magnification 40x). The medical silicone in its surface layer is totally covered with biofilm that infiltrate the texture of the silicone in the thickness of about 0.7 mm with a columnar pattern. The portion of prosthesis constituted by Teflon appeares resistant to penetration of biofilm aggregates.
Conclusion
The analysis and identification of biofilms on speech prostheses play an important role in the prevention of colonization and device’s survival especially in order to improve the quality of life in laryngectomized patients. Moreover, the use of biofilm discloser on the voice prosthesis may be advantageous in detecting biofouling specific sites and facilitating brushing during daily prosthesis cleaning.
Declarations
Conflict of interest
The authors declare not to have conflict of interests and they don’t have financial supports.
Footnotes
Publisher's Note
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