Dynamic evaluation of sutureless vitrectomy wounds: an optical coherence tomography and histopathology study.
OBJECTIVE
To investigate the in vitro dynamic wound morphology of fresh 25- and 23-gauge sutureless sclerotomy wounds.


METHODS
Experimental study; laboratory investigation.


METHODS
Sixteen eyes of New Zealand white rabbits.


METHODS
Eight cadaver heads were obtained, and the eyes were enucleated with their conjunctiva intact to simulate an intact globe. Four eyes were analyzed using 4 different wound types and cannula sizes: 25-gauge straight incision (group a); 25-gauge angled incision (group b); 23-gauge straight incision (group c); and 23-gauge angled incision (group d). Three incisions were created in each eye using either a 25- or 23-gauge trocar/cannula system. Intraocular pressure (IOP) was controlled with intraocular balanced salt solution infused through the infusion cannula. The incisions were imaged with a prototype, anterior segment spectral domain optical coherence tomography device under variable IOP to simulate successive blinks or rubbing of the eye and to evaluate the wounds in a dynamic state. Finally, India ink was applied to the surface of the eye under variable IOP to evaluate for wound leakage and potential ink ingress. The eyes were then analyzed by frozen section.


METHODS
Wound gaping as evaluated with optical coherence tomography (OCT) and presence of India ink particles in incisions evaluated by histology.


RESULTS
Gross examination revealed obvious leakage of intraocular fluid in groups A and C (straight incisions) under variable IOP, with some even developing conjunctival blebs. Groups B and D (angled incisions) demonstrated minimal to no clinical leakage. Spectral domain optical coherence tomography demonstrated open wounds in straight incisions under all IOP conditions, with a slightly larger open wound under high IOP. Angled incisions demonstrated less wound gap overall and better wound apposition under high IOP versus low IOP. Histologic examination revealed India ink particles in all straight incisions with penetration across the whole incision in some wounds, whereas no ink particles were observed in angled incisions.


CONCLUSIONS
Angled incisions have been proposed for sutureless vitrectomy to prevent wound leakage, hypotony, and the secondary risk of endophthalmitis. This study demonstrates that angled incisions provide better wound apposition under dynamic IOP conditions immediately after formation that simulate real-world situations: blinking, squeezing, or even rubbing of the eye.


BACKGROUND
Proprietary or commercial disclosure may be found after the references.
Taban
Mehran
M
Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio 44195, USA.
Ventura
Alexandre A C M
AA
Sharma
Sumit
S
Kaiser
Peter K
PK
D000818:Animals; D002244:Carbon / Q000378:metabolism; D007429:Intraocular Pressure; D008866:Microsurgery / Q000379:methods*; D011817:Rabbits; D012590:Sclera / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D012599:Sclerostomy; D013529:Surgical Wound Dehiscence / Q000175:diagnosis* / Q000378:metabolism; D013536:Suture Techniques; D041623:Tomography, Optical Coherence; D014821:Vitrectomy / Q000379:methods*; D014945:Wound Healing
C028433:chinese ink; D002244:Carbon