Abstract
Purpose::
To demonstrate the feasibility of scleral wound closure using a novel adhesive made of chitosan film in a porcine model.
Methods::
5-mm full-thickness radial scleral lacerations were created 5 mm posterior to the limbus in enucleated whole porcine globes using a 15 degree scalpel. Chitosan films were created by a casting technique and sized to 8 x 8 mm patches. After drying the bare scleral surface, lacerations were sealed with either chitosan film alone (4 eyes) or chitosan film followed by robotically guided laser irradiation (4 eyes). Laser irradiation was performed using an near infrared laser (1455 nanometer wavelength) in a raster pattern (20mm/sec) perpendicular to the incision with a power level of 350-450mW for 6 minutes. Three eyes were closed by hand with 10-0 nylon suture for comparison. Time to complete closure and burst pressure were determined for each eye. Burst pressure was determined by slowly inflating the vitreous cavity with normal saline via an 18 gauge needle penetrating the optic nerve. A pressure transducer attached to the tubing monitored intraocular pressure. One eye of chitosan alone, and chitosan followed by laser application did not undergo burst pressure determination, but instead were preserved in formalin for histologic examination.
Results::
Mean time for scleral closure with chitosan film was 2.49 minutes (range 2.2 - 3.26, 4 eyes) with a mean burst pressure of 303 mm Hg (range 217 - 364, 3 eyes). Mean time for scleral closure with chitosan followed by laser application was 12.83 minutes (range 11.45 - 14.15, 4 eyes) with a mean burst pressure of 454.6 mm Hg (range 152 - 721, 3 eyes). Suture closure required a mean time of 5.53 minutes (range 4.3 - 7.3, 3 eyes) and a mean burst pressure of 570 mm Hg (range 460 - 646, 3 eyes). Histologic images are included.
Conclusions::
In this preliminary study chitosan successfully closed scleral lacerations with and without the application of laser energy. While laser irradiation increases the duration of closure time, it appears to strengthen the closure bond. Chitosan based adhesives hold promise as a scleral wound closure technique.
Keywords: wound healing • sclera • trauma