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Cannula ejection into the cornea during wound hydration

University of Arkansas for Medical Sciences, Jones Eye Institute, Little Rock, AR, USA

Correspondence: Dr Michael N Wiggins
Email: wigginsmichael{at}uams.edu Jones Eye Institute, University of Arkansas for Medical Sciences, 4301 West Markham, Slot 523, Little Rock, AR 72205-7199, USA; Tel: +1-501-686-5150; Fax: +1-501-603-1289

Date of acceptance: 20th November 2007

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Introduction

The pressure generated inside a syringe can cause a sudden ejection of a cannula when the cannula is not properly secured. Cannula-induced damage during eye surgery has rarely been reported, but is suspected to have a more widespread occurrence.1 Ocular damage has ranged from iris perforation and hyphema to vitreal hemorrhage and retinal damage.1-4 Our report adds support to the recommendation that the surgeon confirm the security of the cannula prior to use.

Case Report

A 60 year old white female underwent routine, clear-cornea phacoemulsification for a symptomatic nuclear sclerotic cataract on her right eye. The main wound was located at the 145 degree meridian and enlarged to 3.5mm for injection of a foldable intraocular lens. At the end of the case, hydration of the main wound with a 3 cc plastic Luer lock syringe with a 25 gauge angled cannula was attempted. During this step, the cannula was inadvertently ejected from the syringe and entered the mid-corneal stroma, exiting the cornea into the anterior chamber angle. Subsequent corneal hydration outlined the damaged area, which was also noted on an Oculus-Pentacam HR (high resolution) Scheimpflug scan (Figure 1).

Figure 2. External photo of the right eye 6 days after surgery. The stromal cleavage plane can be visualized superior-temporally (black arrow). The suspected iatrogenic stromal tract is outlined with white arrows.

Discussion

Stromal hydration of the main corneal wound at the end of cataract surgery is commonly performed to help seal the wound for at least 24 hours.5,6 Although a seemingly innocuous step, stromal hydration has been reported to result in vitreous loss on three occasions when ejection of the cannula has occurred.2,3,7 Additionally, Rumelt et al describes 3 cases of cannula ejection during stromal wound hydration over a 15 year period and suggests the occurrence is either rare or under-reported.1 Other reports of cannula ejection have been associated with the use viscoelastics and the resistance created by their viscosity.1,4

Previous reports advocate the use of a Luer lock over a slip lock syringe to avoid this complication. However, Pandey and Scott reported a case of cannula dislodgement during wound hydration using a Luer lock syringe resulting in a total retinal detachment.7 To our knowledge, our report is the second case of cannula ejection from a Luer lock syringe. It is also the first report of a cannula ejection resulting in corneal perforation. The images from the Pentacam™ show the location of the corneal lesion to be in the midstroma, approximately 378 to 482 microns from the corneal surface. Fortunately, this area was located outside of the central visual axis and was not visually significant. During routine operations, surgeons striving for efficiency can overlook small tasks such as confirming the attachment of a cannula prior to intraocular use. Steps, such as the choice of Luer lock over slip lock syringes, can be taken to reduce the potential for complications. However, poorly secured cannulas can result in ocular damage regardless of syringe type. Therefore, surgeons should confirm the security of all cannulas prior to use.

Acknowledgement

This work was supported in part by unrestricted grants from Research to Prevent Blindness and the Pat & Willard Walker Eye Research Center.

References