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“A Comparison of Wound Strength with and without Hydrogel Liquid Ocular Bandage in Human Cadaver Eyes” This study was supported in part by an unrestricted.

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Presentation on theme: "“A Comparison of Wound Strength with and without Hydrogel Liquid Ocular Bandage in Human Cadaver Eyes” This study was supported in part by an unrestricted."— Presentation transcript:

1 “A Comparison of Wound Strength with and without Hydrogel Liquid Ocular Bandage in Human Cadaver Eyes” This study was supported in part by an unrestricted grant from Becton, Dickinson and Company, Waltham, MA, USA; and by an unrestricted grant from Research to Prevent Blindness, Inc., New York, NY, to the Department of Ophthalmology & Visual Sciences, University of Utah. Dr. Olson is a consultant to Becton, Dickinson and Company. Surekha Maddula, M.D., Don K. Davis, M.D., Peter J. Ness, M.D., Randall J. Olson, M.D. Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah

2 Introduction  The advancements in microsurgery and disadvantages of sutures has shifted toward sutureless surgery in clear corneal incisions and pars plana vitrectomy procedures  However, sutureless incisions are more likely than sutured incisions to leak after surgery, and a leaky wound is a potential source for bacterial endophthalmitis 1,2  Studies show that post operative leaking and sutureless surgery is associated with endophthalmitis due to ingress and egress of ocular fluids from changing ocular pressure 2-5

3 Introduction   Adhesive sealants on corneal or scleral wounds may be a solution to early post-operative incision leakage   Polyethylene glycol (PEG) hydrogels are synthetic materials that may have advantages over biological materials. Hydrogel liquid ocular bandages are safe Comfortable Easy and quick to apply Persist on for several days Protect the wound Enhance wound strength

4 Objective The purpose of this study is to determine whether a hydrogel liquid ocular bandage is efficacious in improving wound strength.

5 Materials and Methods  5 cadaver eyes were obtained from Lions Eye Bank to test a total of 20 23-gauge incisions and 20 clear corneal incisions  In each eye a 23-gauge pars plana vitrectomy with Alcon Infinity was performed to remove vitreous that may potentially block incisions  Pars plana incisions were created with 23-gauge MVR blades then tested for wound bursting strength by increasing bottle height of BSS connected to the optic nerve via 23-gauge needle.  Each incision was tested with and without hydrogel liquid bandage, Ocuseal and then sealed with cyanoacrylate for a total of 4 pars plana incisions in each eye  A clear corneal incision was then made with a 2.8mm angled steel blade and the iris was removed, lens dislocated posteriorly and needle in optic nerve advanced into the anterior chamber  Each clear corneal incision was then tested with and without Ocuseal and then sealed with cyanoacrylate for a total of 4 clear corneal incisions in each eye

6 23 Gauge IncisionsClear Corneal Incisions Bursting Pressure w/o ocuseal (mmHg) Bursting Pressure with ocuseal (mmHg) Bursting Pressure w/o ocuseal (mmHg) Bursting Pressure with ocuseal(mmHg) Cadaver Eye #1 Incision #118.6246.2 (no burst)37.2100.7 Incision #214.9246.2 (no burst)44.7110 Incision #335.4212.635.489.5 Incision #444.7210.718.696.9 Cadaver Eye #2 Incision #187.7246.2 (no burst)93.2169.7 Incision #244.8246.2 (no burst)67.1175.3 Incision #355.9 246.2 (no burst) 70.9246.2 (no burst) Incision #450.4 246.2 (no burst) 95.1194 Cadaver Eye #3 Incision #165.317941233.1 Incision #276.5167.855.9195.8 Incision #370.9158.5252.1 246.2 (no burst) Incision #476.5160.444.7 246.2 (no burst) Cadaver Eye #4 Incision #157.8231.367.1 246.2 (no burst) Incision #237.318.652.2 246.2 (no burst) Incision #346.623552.2171.6 Incision #469246.2 (no burst)67.1214.5 Cadaver Eye #5 Incision #128190.257.8240.6 Incision #226.1186.5102.6 246.2 (no burst) Incision #326.1246.2 (no burst)67.1 246.2 (no burst) Incision #426.191.467.1 246.2 (no burst) Results

7 Results   Mean Leakage pressure was determined and compared using a student T-test.   For non-parametric testing a Chi-square analysis was used.   With four comparisons, significance with a Bonferroni correction for multiple comparisons was set at P<.012

8 Results 2.8 mm Corneal Incisions23-Gauge Scleral Incisions Mean Leakage without liquid ocular bandage59.5 +/-21.0mmHg47.9+/-21.4mmHg Mean Leakage with liquid ocular bandage198.1+/-57.6mmHg200.6+/-60.4mmHg P value for above two comparisons P<.0001 Number of Incisions without leakage at maximal pressure without bandage 0 out of 20 Number of Incisions without leakage at maximal pressure with bandage 8 out of 207 out of 20 P value for above two comparisonsP =.009 P =.014 Table. Intraocular pressure at which incision leakage was noted for both 23-gauge scleral and 2.8 mm limbal incisions in human cadaver eyes, both with and without use of a hydrogel liquid bandage formulated for ocular use. Our maximal attainable intraocular pressure was 246mmHg, the figure which we used when the incision did not leak at this pressure. We also compare the number of incisions that did not leak at our maximal attainable pressure of 246mmHg.

9 Discussion   The goal of an ocular bandage is to protect injured tissue, and to help the reemergence of a normal anatomic and functional state of the ocular incision through wound remodeling and repair.   Advantages to synthetic hydrogel sealants over fibrin and cyanoacrylate alternatives: Quick and easy to prepare and use Can be applied at neutral pH 1 Require no external energy source Safe and tolerable in the eye, non-toxic and no antigenicity or immune response 6 85% water content after application; has physical properties comparable to tissue, and suitable to fill in irregularities and conform to the normal architecture Polymerization after application takes approximately 45 seconds to achieve maximal strength Watertight and flexible that cornea can resist egress and ingress of ocular surface contaminants by 92% over incisions without such a bandage 7 Removal is not an issue as it breaks down under physiological conditions and degradation products are water soluble and cleared through body

10 Conclusions   Postoperative hypotony and fluctuations in intraocular pressure secondary to incision leakage is a concern 8-10   Pressure changes in the eye are consequences of a faulty incision and can cause egress of the contaminated tear film into the eye, potentially leading to endophthalmitis   A hydrogel liquid bandage has the potential advantage of easy and quick application, is well tolerated, and resists incision distortion due to its malleable nature   Our results showed that the hydrophilic acrylic hydrogel PEG bandage is statistically significant for resistance to wound leakage at very high intraocular pressures for both 2.8mm corneal incisions and 23-gauge scleral incisions.   Application of hydrogel liquid ocular bandage allows for substantially higher intraocular pressures before leakage when compared to the native wound and we suggest its use in the early postoperative period for procedures using sutureless incisions.

11 References  1.Grinstaff MW. Designing hydrogel adhesives for corneal wound repair. Biomaterials 2007; 28:5205-5214  2.Nagaki Y, Hayasaka S, Kadoi C, Matsumoto M, Yanagisawa S, Watanabe K, et al. Bacterial endophthalmitis after small-incision cataract surgery. effect of incision placement and intraocular lens type. J Cataract Refract Surg 2003; 29:20-26  3.Results of the Endophthalmitis Vitrectomy Study. A randomized trial of immediate vitrectomy and of intravenous antibiotics for the treatment of postoperative bacterial endophthalmitis. Endophthalmitis Vitrectomy Study Group. Arch Ophthalmol 1995; 113:1479-1496  4.Wallin T, Parker J, Jin Y, Kefalopoulos G, Olson RJ. Cohort study of 27 cases of endophthalmitis at a single institution. J Cataract Refract Surg 2005; 31:735-741  5.Kunimoto DY, Kaiser RS. Incidence of endophthalmitis after 20- and 25-gauge vitrectomy. Ophthalmology 2007; 114:2133-2137  6.Kim T, Kharod BV. Tissue adhesives in corneal cataract incisions. Curr Opin Ophthalmol 2007; 18:39-43  7.Hovanesian JA. Cataract wound closure with a polymerizing liquid hydrogel ocular bandage. J Cataract Refract Surg 2009; 35:912-916  8.Irak-Dersu I, Nilson C, Zabriskie N, Durcan J, Spencer HJ, Crandall A. Intraocular pressure change after temporal clear corneal phacoemulsification in normal eyes. Acta Ophthalmol 2009 [Epub ahead of print]  9.Schwenn O, Dick HB, Krummenauer F, Krist R, Pfeiffer N. Intraocular pressure after small incision cataract surgery: temporal sclerocorneal versus clear corneal incision. J Cataract Refract Surg 2001; 27:421-425  10.Gupta OP, Ho AC, Kaiser PK, Regillo CD, Chen S, Dyer DS, et al. Short-term outcomes of 23-gauge pars plana vitrectomy. Am J Ophthalmol 2008; 146:193-197


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