CO(2) laser fiber soft cochleostomy: development of a technique using human temporal bones and a guinea pig model.

OBJECTIVE: A novel approach for creating a soft cochleostomy has been described using a handheld CO(2) laser hollow waveguide from termed in the following the handheld CO(2) laser fiber. The effects on cochlear function have been studied in an animal model and were compared to the effects of the micro drill. STUDY DESIGN: Combined human temporal bone and experimental animal study. MATERIALS AND METHODS: Four human temporal bones were used to describe the technique to create a cochleostomy using the handheld CO(2) laser fiber. A cochleostomy was made by thinning the cochlear wall with a motorized drill and by creating an opening with the CO(2) laser fiber. Eighteen guinea pigs were used to investigate the effects of the CO(2) laser and the drill on cochlear function. An electrode was placed in the round window niche to measure compound action potentials (CAPs). Baseline cochlear function was determined by recording CAP thresholds evoked by acoustic tone pips and was re-assessed during and after a cochleostomy was made. The protocol was repeated using a diamond-burr drill technique. RESULTS: The handheld CO(2) laser fiber is an ideal tool to create cochleostomies under 1 mm in diameter. In the guinea pig animal model, CAP thresholds showed little change after creating the cochleostomy at 4 W laser power setting and revealed focal threshold elevations averaging 32 dB at higher laser power settings. CONCLUSIONS: The human temporal bone study introduces a novel surgical approach for soft cochleostomies that uses both the drill and the CO(2) laser fiber. Threshold elevations, which were observed after making the cochleostomy with the laser, compared favorably to the diamond burr technique.

Enhanced adenoviral-vector mediated gene transfer using human albumin solder.

BACKGROUND AND OBJECTIVE: Laser tissue welding with human albumin solder (HAS) has been used as an alternative method of wound closure. Adenoviral vectors have been used to introduce various cytokine genes into wounds to accelerate wound closure. In the present study, we were interested in the effect of HAS on adenoviral vector transfer of the beta-galactosidase (beta-gal) gene in vitro and in vivo. STUDY DESIGN/MATERIALS AND METHODS: 3T3 fibroblasts were used to study the effect of HAS on beta-gal gene transfer in vitro. The presence of beta-gal was determined by Western blot, and its activity by a colorimetric assay. A punch biopsy model of wound healing in pigs was used for in vivo experiments. RESULTS: HAS increased the efficiency of adenoviral-mediated beta-gal transduction and stabilized the adenovirus at room temperature. HAS protected adenovirus from inactivation by laser, both in vitro and in vivo. CONCLUSIONS: HAS may stabilize adenoviral vectors to deliver cytokine genes in future wound healing experiments.