Prevention of pharyngocutaneous fistulas by means of laser-weld techniques

Underlay Tympanoplasty with Laser Tissue Welding

We investigated the feasibility of using laser tissue welding techniques to perform transcanal underlay tympanoplasty. We used 10 temporal bones obtained from human cadavers. After creating a subtotal tympanic membrane perforation, we introduced harvested periosteum through the perforation and used laser tissue welding to secure the periosteum graft in place in an underlay fashion. The procedure was performed via a transcanal approach and did not require middle ear packing. Immediately after the graft had been placed, we qualitatively tested its integrity with a blunt probe. The graft was as strong as the native cadaver tympanic membrane in all 10 cases. We conclude that laser transcanal underlay tympanoplasty is a feasible and effective method of repairing a tympanic membrane. The ultimate goal is to develop a technique that will allow physicians to routinely perform underlay tympanoplasty on moderately sized perforations in an office setting.

Dural Closure with Laser Tissue Welding

This study investigates the use of tissue-soldering techniques to substitute or reinforce traditional suture closure of dural incisions. Fresh human cadaveric dura was incised and subsequently closed by use of three techniques: (1) conventional interrupted suture with 4–0 silk ( n = 25), (2) laser solder reinforced suture closure ( n = 25), and (3) laser solder closure alone ( n = 25). Anastomosis tensile strength and hydrostatic leak pressures were measured. Dural repair was also performed in 15 live Lewis rats. Dural closure was accomplished with 9–0 Prolene sutures ( n = 5), laser-reinforced suture closure ( n = 5), and laser solder closure alone ( n = 5). Histologic examination of the closure immediately after soldering and 2 weeks later was performed. Suture closure alone had the lowest leak pressure, 9.4 ± 1.7 mm Hg, and an intermediate break point, 13.3 ± 2.1 Kgf/cm2. Measurements with laser solder alone revealed a mean leak pressure of 26.2 ± 3.7 mm Hg and a break point of 4.6 ± 1.4 Kgf/cm2. Solder-reinforced suture closure leak pressure measured 64.0 ± 6.7 mm Hg and 21.4 ± 2.4 Kgf/cm2. There was a statistically significant increase in leak pressure and tensile strength in the closures performed with laser weld reinforcement of traditional suture technique ( p = 0.0001). Dural closure with laser tissue welding alone provided an immediate leak-free closure, but with poor tensile strength. Histologic examination of welded dura and underlying brain tissue showed no evidence of thermal injury in four of five animals studied. Laser welding may significantly decrease the incidence of cerebrospinal fluid leak after dural closure. In addition, laser tissue welding also makes dural closure possible where space constraints make traditional suture closure difficult.