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Cataract Surgery Wound Burn, Corneal Incision Contracture

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Title: Cataract Surgery Wound Burn, Corneal Incision Contracture
Authors: Nathanael Jensen, MSI, Rebekah Gensure, MD, PhD, Jeff Pettey, MD
Photographer: Ethan Peterson
Date: 02/26/2020

Background

Phacoemulsification has become a safe and reliable method for cataract extraction. However, one rare complication of phacoemulsification is corneal incision contracture (CIC), more commonly known as wound burn. CIC has been reported in 0.037% of cataract cases in the United States and Canada.1 A second study limited to the U.S. determined the incidence of CIC to be 0.098%.2 CIC is an injury to the sclerocorneal or clear corneal tunnel as a result of the thermal energy created by an overheated metallic phaco needle.3 Acute contracture and distortion of the tissue occurs when temperatures exceed 60°C, leading to loss of the self-sealing capacity of the wound.1 Such wounds are difficult to heal and increase the risk of postoperative astigmatism.4

Risk Factors

Studies have successfully identified risk factors that can lead to CIC during phacoemulsification. First, higher levels of ultrasound energy are known to increase the risk of CIC.1 It is recommended to use only as much ultrasound energy as needed and at the lowest possible level to emulsify the cataract.

Second, utilization of certain surgical approaches to nuclear disassembly can be a risk factor for CIC. Chop approaches that rely heavily on mechanical force (such as the full chop or dry chop approach) have been shown to result in a lower incidence of CIC than disassembly techniques that rely more on ultrasound (such as the divide-and-conquer, carousel, and stop-and chop approaches).1

Third, and most importantly, interruptions to fluid flow around the phaco tip increase the risk of CIC, particularly when the tip is immersed in ophthalmic viscosurgical devices (OVDs). An occluded tip surrounded by OVD shows a dramatic temperature rise to temperatures capable of CIC within seconds. High viscosity OVDs have a higher incidence of CIC1 as viscous OVDs themselves can clog the phaco tip and prevent the cooling effects of fluid flow around the tip. Stoppage of inflow may also result due to factors such as “wound compression of the irrigating sleeve, sleeve kinking by handpiece movements, tubing setup errors, and lowering or emptying of the fluid bottle.”4

Video Description

Case 1 documents an instance of CIC as ultrasound is engaged with an occluded tip in an anterior chamber full of viscoelastic. The video identifies the first signs of CIC, around 2 seconds after phacoemulsification begins.

Case 2 illustrates another example of CIC where again the tip is occluded, ultrasound is engaged, and the tip is bathed in OVD.  The video identifies the first signs of CIC, roughly 3 seconds after phacoemulsification begins. In this case, we can also see that the phacoemulsification sleeve is twisted, which may also be a contributing factor.

Both cases illustrate the rapid nature of CIC development.

Case 1 Video

Case 2 Video

Summary of the Case:

Although CIC is thankfully a rare complication of cataract surgery, surgeons must be adept recognizing the signs of CIC immediately. The ideal approach is to prevent CIC in the first place. Strategies to avoid CIC include using the least amount of ultrasound energy necessary for effective phacoemulsification, employing mechanical forces instead of ultrasound forces when appropriate for lens disassembly, using lower viscosity OVDs, and taking care to listen for the occlusion bell to minimize interruptions to normal fluid flow around the phaco tip.

Format: Video

References:

  1. Sorensen T., Chan C.C., Bradley M., Braga-Mele R., and Olson R.J.: Ultrasound-induced corneal incision contracture survey in the United States and Canada. J Cataract Refract Surg 2012; 38: pp. 227-233)
  2. Bradley M.J., and Olson R.J.: A survey about phacoemulsification incision thermal contraction incidence and causal relationships. Am J Ophthalmol 2006; 141: pp. 222-224
  3. Haldar K, Saraff R. Closure technique for leaking wound resulting from thermal injury during phacoemulsification. J Cataract Refract Surg. 2014;40(9):1412–1414.
  4. Sugar A., and Schertzer R.M.: Clinical course of phacoemulsification wound burns. J Cataract Refract Surg 1999; 25: pp. 688-692)

Faculty Approval by: Dr. Jeff Pettey, MD

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