Biofilm formation in vivo on perfluoro-alkylsiloxane-modified voice prostheses

Objective: To study the influence of perfluoroalkylsiloxane (PA) surface mo dification of silicone rubber voice prostheses on biofouling. Design: Placebo-controlled clinical trial. Setting: Tertiary referral center, with specialization in head and neck can cer treatment. Patients: Eighteen consecutive patients with laryngectomies and experienced in the use of a voice prosthesis who visited the outpatient clinic for pro sthesis replacement. Material: Eighteen partially surface-modified voice prostheses (3 with shor t-chain PAs [1 fluorocarbon unit] and 15 with long-chain PAs [8 fluorocarbo n units]) were inserted via the patients' tracheoesophageal shunts and rema ined in place for 2 to 8 weeks. Intervention: Replacement of the prostheses. Main Outcome Measures: Evaluation of biofilm formation on short- and long-c hain PA-modified and original silicone rubber surfaces on the esophageal si de of the voice prosthesis. Results: The planimetrical biofilm scores of the surfaces of all 3 short-ch ain PA-treated voice prostheses indicated more biofouling on the treated su rfaces than on the untreated surfaces of the same prostheses. For the long- chain PA-treated prostheses, the planimetrical biofilm scores, as well as t he numbers of colony-forming units per cm(-2) for bacteria and yeasts, indi cated less biofouling on the created side than on the control side for 9 of the 13 prostheses that could be analyzed (2 were lost to analysis). Identi cal fungal strains, mainly Candida sp, were isolated from biofilms on each side of the esophageal flange. Conclusions: Chemisorption of long-chain PAs by the silicone rubber used fo r voice prostheses reduces biofilm formation in vivo and therefore can be e xpected to prolong the life of these prostheses. Chemisorption of short-cha in PAs by silicone rubber seems to have an adverse effect.