Exposed polypropylene flange in the Canabrava double-flanged polypropylene technique

Canabrava, Sergio Felix MD; Rabelo, Neiffer Nunes MD; de Sousa Lima, Josiane Lílian MD; de Nadai, Ramon Fazzolo MD

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doi: 10.1097/j.jcro.0000000000000058
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We have previously described the double-flanged polypropylene technique, which uses an intraocular lens (IOL) haptic to achieve knotless scleral fixation of a capsular tension segment in the setting of zonular instability.1 Since then, this technique has been adapted for use in the IOL, iridodialysis repair, and artificial iris fixation.2–5

As with all scleral fixation techniques, there is a potential infection risk if the fixation material is incorrectly positioned or there is transconjunctival erosion. As such, the length of the haptic, position of the flange, and alignment of the capsular tension ring/IOL are all important intraoperative considerations to avoid complications such as endophthalmitis and IOL decentration or inclination.6,7 In this article, we present a case report that describes how to manage suture displacement to reduce the risk of postoperative complications.


A 70-year-old patient had previously undergone a 4-flanged technique using a single-piece PMMA CZ70BD with an eyelet IOL (Alcon Laboratories, Inc.) fixed to the sclera with 2 double flanges polypropylene with a 5-0 polypropylene in each side.2 He presented 30 days postoperatively with pain and decreased vision and demonstrated a localized mild conjunctival reaction.

Biomicroscopic examination of the eye demonstrated an exposed polypropylene flange temporally, which had eroded through the conjunctiva but was Seidel negative (Figure 1). The cornea was otherwise clear; there was no anterior chamber reaction or vitritis. Intraocular pressure was 11 mm Hg. We initiated topical moxifloxacin every 3 hours for 7 days and scheduled the patient's surgery the following week.

Figure 1.:
An exposed distal flange of a polypropylene was noted as the cause of the patient's irritation.

Patient Consent

The patient signed a written consent form that gives consent to the use and publication of their data.

Surgical Technique

During surgery, the tip of a 26G insulin needle was used to pry up the partially exposed suture flange. A 23G microforceps was used to stabilize the suture base at the external sclerotomy (Figure 2, A). We then used a pair of straight Vannas scissors (Beaver-Visitec International) to cut the redundant suture length (Figure 2, B). We recreated a replacement, smaller flange using thermocautery (Figure 2, C). Finally, the new flange was buried inside the scleral tunnel (Figure 2, D). Figure 3 shows the flange buried in the scleral tunnel at 30 days postoperatively.

Figure 2.:
A: Externalization of the flange was performed using an insulin needle, and it was then held close to the sclera using the microforceps. B: The flange suture was then cut 2 mm from the microforceps edge. C: A secondary flange was created using thermocautery. D: Finally, the new flange was buried inside the scleral tunnel.
Figure 3.:
The secondary flange is buried—30 days postoperatively.


We hypothesize that compared with other scleral fixation techniques, the use of the double-flanged polypropylene in the 4-flanged technique results in a simpler and quicker surgical procedure and presents less risk of suture breakage.2,3 However, failure to perform the technique correctly, particularly to correctly position the suture flanges, can lead to serious complications such as endophthalmitis.

One of the challenges in the double-flanged technique is successfully burying the suture flanges in the sclera to avoid the risk of extrusion, which could be an entry site for bacterial flora and therefore increase the risk of endophthalmitis. We have performed the double-flanged scleral fixation in over 70 eyes to day and we have not encountered a case of post-operative endophthalmitis but this has been reported in a recent case report.5

Two factors can contribute to this complication. The first is a polypropylene suture that is too long and thus generates insufficient tension between the sclera and the IOL haptic, capsular tension segment, or artificial iris. If this occurs, the external flange can externalize and produce an entry site for microorganisms.2 The second factor is an unobstructed scleral tunnel. The tunnel where the polypropylene suture is inserted should be completely obstructed by the buried flange. This prevents subsequent suture mobility and seals the scleral tunnel.2

Obata et al. reported a case of endophthalmitis secondary to an exposed haptic after an intrascleral IOL fixation using the Yamane technique.8 In another case report, Matsui et al. identified that haptic exposure can be caused by poor surgical technique or erosion or fragility of the fixed sclera.9

There were no pre-existing conditions of the eye that caused the flange exposure. We believe it happened because of the inappropriate tension in the polypropylene made when the IOL was placed in its final position. Therefore, we suggest that eyes with scleral fixation should be periodically monitored postoperatively to ensure the correct position of the fixation material and the absence of signs of infection.

In the authors' 4 years of experience applying the double-flanged technique in more than 70 eyes, we suggest the following 3 technical considerations to reduce the risk of suture exposure and subsequent infection.

Perhaps the most crucial step in avoiding complications related to an exposed flange is to create a long, beveled intrascleral tunnel, as this will allow the insertion of the flange into the sclera. If the sclerostomy is created by passing the needle directly and perpendicularly to the sclera, without the creation of a tunnel, then there will be insufficient space to bury or embed the flange, which will increase the risk of exposure.

Another important step to prevent flange exposure is to increase the tension of the polypropylene suture by holding its base with a 23G microforceps in close apposition to the sclera. This will avoid a long polypropylene suture that can exteriorize in the future. The polypropylene suture should be cut 2 mm from the microforceps. In the researchers' experience, this is the ideal size for making a flange to be buried in the sclera.

The final step is to ensure that the flange is completely buried within the scleral tunnel at the end of the surgery.

Surgeons must be aware of the importance of burying a flange correctly into the scleral tunnel and the potential risk for endophthalmitis because of exposed polypropylene flanges. If a suture is found to be exposed, it is important to reposition the suture as we have described in this case report.

In addition, all patients undergoing scleral fixation should be advised to promptly seek medical attention should they notice any signs of eye irritation.

The new technique of scleral fixation has been shown to be an effective and adaptable surgical approach in a number of surgical situations. However, the surgical considerations presented in this case report are necessary to reduce the risk of postoperative complications such as endophthalmitis.


  • Flanged fixation technique is widely used.
  • There is a potential infection risk and complications if the fixation material is incorrectly positioned.


  • Surgical pearls to avoid complications with a double-flanged fixation technique.


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2. Canabrava S, Andrade N Jr, Rezende PH. Scleral fixation of a four-eyelets foldable intraocular lens in patients with aphakia using a four-flanged technique. J Cataract Refract Surg 2021;47:265–269
3. Canabrava S, Canêdo Domingos Lima AC, Ribeiro G. Four-flanged intrascleral intraocular lens fixation technique: no flaps, no knots, no glue. Cornea 2020;39:527–528
4. Kusaka M, Miyamoto N, Akimoto M. Repairing iridodialysis by riveting with a double-flanged polypropylene suture. J Cataract Refract Surg 2019;45:1531–1534
5. Khachikian S. Canabrava Double-Flanged Technique and Aniridia. San Francisco, CA: American Academy of Ophthalmology; 2015. Available at: Accessed December 15, 2020
6. Roditi E, Brosh K, Assayag E, Weill Y, Zadok D. Endophthalmitis associated with flange exposure after a 4-flanged Canabrava fixation technique. JCRS Online Case Rep 2021;9:pe00042
7. Kurimori HY, Inoue M, Hirakata A. Adjustments of haptics length for tilted intraocular lens after intrascleral fixation. Am J Ophthalmol Case Rep 2018;10:180–184
8. Obata S, Kakinoki M, Saishin Y, Ohji M. Endophthalmitis following exposure of a haptic after sutureless intrascleral intraocular lens fixation. J Vitreoretin Dis 2018;3:247412641880899
9. Matsui Y, Matsubara H, Hanemoto T, Kondo M. Exposure of haptic of posterior chamber intraocular lens after sutureless intrascleral fixation. BMC Ophthalmol 2015;15:104
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