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

To study the influence of perfluoroalkylsiloxane (PA) surface modification of silicone rubber voice prostheses on biofouling.

Placebo-controlled clinical trial.

Tertiary referral center, with specialization in head and neck cancer treatment.

Eighteen consecutive patients with laryngectomies and experienced in the use of a voice prosthesis who visited the outpatient clinic for prosthesis replacement.

Eighteen partially surface-modified voice prostheses (3 with short-chain PAs [1 fluorocarbon unit] and 15 with long-chain PAs [8 fluorocarbon units]) were inserted via the patients' tracheoesophageal shunts and remained in place for 2 to 8 weeks.

Replacement of the prostheses.

Evaluation of biofilm formation on short- and long-chain PA-modified and original silicone rubber surfaces on the esophageal side of the voice prosthesis.

The planimetrical biofilm scores of the surfaces of all 3 short-chain PA-treated voice prostheses indicated more biofouling on the treated surfaces than on the untreated surfaces of the same prostheses. For the long-chain PA-treated prostheses, the planimetrical biofilm scores, as well as the numbers of colony-forming units per cm(-2) for bacteria and yeasts, indicated less biofouling on the treated side than on the control side for 9 of the 13 prostheses that could be analyzed (2 were lost to analysis). Identical fungal strains, mainly Candida sp, were isolated from biofilms on each side of the esophageal flange.

Chemisorption of long-chain PAs by the silicone rubber used for voice prostheses reduces biofilm formation in vivo and therefore can be expected to prolong the life of these prostheses. Chemisorption of short-chain PAs by silicone rubber seems to have an adverse effect.