Abstract
Purpose::
To demonstrate the feasibility of scleral wound closure using bovine serum albumin (BSA) solder and computer-guided laser in a porcine eye model.
Methods::
Eleven enucleated whole pig eyes were dissected down to bare sclera. A 5-mm full-thickness scleral laceration was created radial and beginning 5-mm posterior to the limbus using a 15 degree scalpel blade. Eyes were divided into 3 groups: Group 1: BSA-Immed (4 eyes); Group 2: BSA- 24 hours (4 eyes); and Group 3: Suture (3 eyes). In both BSA groups, the solder (40% BSA, 0.5% hyaluronic acid, 59.5% water) was brought to room temperature and a thin layer brushed over the laceration. The eye was positioned under the laser (single-mode fiber, near infrared, wavelength 1455nm, power 350-450mW) and a computer-generated raster pattern was used to cure the solder. The pattern was perpendicular to the laceration, 20 mm/sec, 1.5mm wide, spaced 0.5mm, for 3 minutes. The solder application/laser cure was repeated twice more. In Group 3, eyes were closed with suture for comparison. Time to closure and leak pressure were determined for each group. For the latter, eyes were slowly infused with normal saline via 18-guage needle passed through the posterior sclera near the optic nerve. This was connected via tubing to a pressure transducer which continuously monitored the pressure. The leak pressure was recorded when the wound began to visibly leak. Leak pressure was measured immediately after wound closure in Groups 1 and 3. Eyes in Group 2 were kept moist in a paper based dressing soaked in a saline solution and refrigerated for 24 hours prior to pressurization. The 4th eye in each BSA group was sent for histopathology.
Results::
Average closure time in Group 1 was 12.2 minutes (range 11.2 to 15.0) with a mean leak pressure of 735.9 mm Hg (range 540 to 1034). Closure time in Group 2 was the similar to Group 1, but leak pressures were lower (mean 326.4, range 242 to 424). Suture closure required a mean time of 5.53 minutes (range 4.3 to 7.3) and resulted in a mean leak pressure of 570.4 mm Hg (range 460 to 646). Histologic analysis is pending.
Conclusions::
Laser tissue welding with a BSA solder and computer-guided laser pattern successfully closed scleral lacerations with leak pressure exceeding that of sutured wounds immediately after wound closure. Although the solder strength degraded approximately 50% by 24 hours after treatment, the wounds remained closed with leak pressure significantly above physiologic pressures. Computer control of the laser delivery may lead to safer, more effective wound closure.
Keywords: wound healing • laser • sclera