Purpose: To report a case of iatrogenic corneal perforation from an ejected cannula.
Methods: Case report.
Results: During corneal tunnel hydration following a successful phacoemulsification procedure, a hydration cannula on a Luer lock syringe was forcefully ejected into the corneal stroma. The cannula exited from the posterior aspect of the cornea and lodged in the anterior chamber angle. The post operative exam revealed an intact iris, no hyphema, and a normal fundus exam. An Oculus-Pentacam HR (high resolution) Scheimpflug scan outlined the area of stromal penetration.
Conclusions: Previous reports advocate the use of Luer lock over slip lock syringes to avoid cannula ejection during intraocular surgery. However, the use of a Luer lock syringe did not prevent a cannula from ejecting into the cornea during wound hydration. Surgeons should therefore not assume that the use of a Luer lock syringe will prevent this occurrence, but should confirm the security of any type of cannula prior to use.
To view the full report and accompanying video please go to: http://bjo.bmj.com/cgi/content/full/92/2/181/DC1
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Cannula ejection into the cornea during wound hydration - video report
Cannula ejection into the cornea during wound hydrationMichael N Wiggins and Sami H Uwaydat
University of Arkansas for Medical Sciences, Jones Eye Institute, Little Rock, AR, USA
Correspondence: Dr Michael N Wiggins
Email: 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
In this video, we can see that while hydrating the temporal aspect of the clear corneal tunnel, the cannula was forcefully ejected, with the tip of the cannula lodging in the angle. The cannula was retracted. Subsequent hydration of the corneal tunnel delineated the potential intra-stromal tract that the ejected cannula had created.
Note: This video is best viewed in Quicktime
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.
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 1. Oculus-Pentacam HR Scheimpflug scan of the clear corneal wound at the 145 degree meridian showing the stromal cleavage plane created by the ejected cannula. 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. The post-operative exam revealed an intact iris, no hyphema, and a normal fundus exam. The patient was noted to have a visual acuity of 20/25 six days postoperatively (Figure 2).
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.
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.
This work was supported in part by unrestricted grants from Research to Prevent Blindness and the Pat & Willard Walker Eye Research Center.
- 1. Rumelt S, Kassif Y, Koropov M, et al. The spectrum of iatrogenic intraocular injuries caused by inadvertent cannula release during anterior segment surgery. Arch Ophthalmol. 2007 Jul;125(7):889-92.
- Bradshaw SE, Shankar P, Maini R, Ragheb S. Ocular trauma caused by a loose sliplock cannula during corneal hydration. Eye. 2006 Dec;20(12):1432-4. Epub 2006 Mar 10.
- Dinakaran S, Kayarkar VV. Intraoperative ocular damage caused by a cannula. J Cataract Refract Surg. 1999 May;25(5):720-1.
- Prenner JL, Tolentino MJ, Maguire AM. Traumatic retinal break from viscoelastic cannula during cataract surgery. Arch Ophthalmol. 2003;121(1):128-129.
- Fine IH, Hoffman RS, Packer M.Profile of clear corneal cataract incisions demonstrated by ocular coherence tomography.J Cataract Refract Surg. 2007 Jan;33(1):94-7.
- Vasavada AR, Praveen MR, Pandita D, Gajjar DU, Vasavada VA, Vasavada VA, Raj SM, Johar K.Effect of stromal hydration of clear corneal incisions: quantifying ingress of trypan blue into the anterior chamber after phacoemulsification. J Cataract Refract Surg. 2007 Apr;33(4):623-7.
- Pandey P, Scott R. Locking the Luer lock. Eye. 2007 Mar;21(3):449-50.
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