ORIGINAL ARTICLE
Sandwich fibrin glue technique for attachment of conjunctival autograft during pterygium surgery Mark A. Fava, MD, FRCSC,*,†,‡ Catherine J. Choi, MD, MS,*,§ George El Mollayess, MD,¶ Samir A. Melki, MD, PhD*,†,‡ ABSTRACT ● RÉSUMÉ Objective: To report the results of a sandwich application of fibrin glue compared with the standard method of using fibrin glue for the attachment of the conjunctival autograft in pterygium surgery. Participants: The study group consisted of 56 consecutive eyes with primary pterygium. Methods: We performed a retrospective analysis comparing the standard method of using fibrin glue for the attachment of the conjunctival autograft during pterygium excision surgery versus the “sandwich technique.” In the “sandwich technique,” the thrombin component of the fibrin glue was applied after the graft was secured in position over a bed of fibrinogen. Results: Graft dehiscence occurred in 3 eyes in the conventional group only. Recurrence occurred in 2 eyes in the conventional group and 1 eye in the sandwich group. None of the values reached statistical significance. Conclusions: The sandwich technique simplifies conjunctival graft fixation during pterygium surgery with conjunctival autograft by allowing more time to properly position the autograft before fibrin clot formation. Objet : Compte-rendu des résultats d'une application sandwich de la colle fibrine comparativement à la méthode standard d'utilisation de la colle fibrine pour la fixité de l'autogreffe conjonctivale dans la chirurgie du ptérygion. Participants : L'étude a porté sur un groupe de 56 yeux consécutifs ayant un ptérygion primaire. Méthodes : Analyse comparative de la méthode standard d'utilisation de la colle fibrine pour la fixation de l'autogreffe conjonctivale dans la chirurgie du ptérygion comparativement à la « technique sandwich ». Dans la « technique sandwich », la composante thrombine de la colle fibrine était appliquée après que la greffe eut été sécurisée dans une position sur un fond de fibrinogène. Résultats : La déhiscence de la greffe s'est produite dans trois yeux du groupe conventionnel seulement. La récurrence est survenue dans deux yeux du groupe conventionnel et un œil du groupe sandwich. Aucune des valeurs n'avait atteint de signification statistique. Conclusion : La technique sandwich simplifie la fixation de la greffe conjonctivale pendant la chirurgie du ptérygion avec une autogreffe conjonctivale en permettant plus de temps pour positionner correctement l'autogreffe avant la formation d'un caillot de fibrine.
The currently preferred method for the surgical management of primary or recurrent pterygium is excision with conjunctival autograft transplantation.1 This technique was initially described by Kenyon et al.2 in 1985 and has proved to be relatively safe and effective with low rates of recurrence.3 This technique has since undergone many variations, the most notable being the use of tissue adhesives for securing the autograft.4–6 A number of studies have demonstrated the safe and desirable effects of fibrin glue in conjunctival autograft surgeries.7–9 Although widespread in its use, the rapidity with which the fibrin glue forms a clot once the components are mixed can be considered a drawback in the current conventional method. We have examined the clinical outcomes of a modified application method of the fibrin glue compared with this conventional method. In this article, we describe a novel use of the components of fibrin glue,
thrombin and fibrinogen, in a “sandwich” manner allowing more time for graft positioning before clot formation.
From the *Massachusetts Eye & Ear Infirmary; †Beth Israel Deaconess Medical Center, Harvard Medical School; ‡Boston Eye Group; §Harvard Medical School, Boston, Mass.; and ¶American University of Beirut Medical Center, Beirut, Lebanon.
Can J Ophthalmol 2013;48:516–520 0008-4182/13/$-see front matter & 2013 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jcjo.2013.07.004
METHODS We describe 56 consecutive eyes with primary pterygia who underwent pterygium excision with conjunctival autograft with either the sandwich fibrin glue technique or the conventional technique described later. The indications for surgery were the pterygium encroaching onto the visual axis and/or persistent irritation and redness refractory to conservative treatments. The risks and benefits of the procedures were reviewed, and the appropriate operative consents were signed. All patients were operated under monitored assisted care anaesthesia supplemented with a retrobulbar injection of lidocaine 2%
Originally received Jan. 6, 2013. Final revision May 19, 2013. Accepted July 16, 2013 Correspondence to Samir A. Melki, MD, Cornea and Refractive Surgery Service, Massachusetts Eye & Ear Infirmary, 243 Charles Street, Boston, MA 02114; [email protected]
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CAN J OPHTHALMOL — VOL. 48, NO. 6, DECEMBER 2013
Sandwich fibrin glue technique—Fava et al. (Hospira, Lake Forest, Ill.) and Marcaine (Bupivacaine) 0.75% (APP Pharm, Schaumburg, Ill.). In the operating theater, each patient was prepped and draped in the usual sterile fashion for ophthalmic surgery. Surgical technique: The sandwich fibrin glue technique
The basic technique of pterygium excision and conjunctival autograft harvesting is well described in the literature.3,10 Tisseel fibrin sealant (Baxter Healthcare Corporation, Westlake Village, Calif.) was used as the tissue adhesive in all cases in this study. To aid in positioning of the globe, we placed one 6–0 silk suture through partial-thickness clear cornea, superiorly and
adjacent to the limbus. The head of the pterygium was first removed from its adhesions to the cornea with blunt dissection and, if necessary, a lamellar plane was created with a #57 Beaver blade (MSP, Rincon, Puerto Rico). The pterygium was then undermined using Westcott scissors with clear identification of the medial rectus muscle before excising the body of the pterygium. Underlying Tenon capsule was then grasped with forceps and excised beyond the conjunctival edges. This bare scleral defect was then measured with calipers. Attention was drawn to the superior conjunctiva to fashion a conjunctival autograft first by injecting lidocaine 2% mixed with epinephrine to create a dissection plane between conjunctiva and underlying Tenon capsule. A suitable autograft was then created
Fig. 1 — Outline of the sandwich fibrin glue technique. A, 6–0 silk clear cornea fixation suture allowing for proper positioning of the globe. B, Head of pterygium excised from its corneal adhesions. C, Body of pterygium excised. D, Underlying Tenon capsule excised. E, Subconjunctival injection of 2% lidocaine (arrow) into superior conjunctival donor site, separating conjunctiva from underlying Tenon capsule. F, Conjunctiva dissected from underlying Tenon capsule with blunt dissection using Westcott scissors. G, Conjunctival autograft excised. H, Conjunctival autograft placed epithelial side down onto cornea. I, Tissue adhesive, first component only (fibrinogen), applied to conjunctival defect. J, Conjunctival autograft positioned into defect. K, Tissue adhesive, second component (thrombin), applied to surface of autograft. CAN J OPHTHALMOL — VOL. 48, NO. 6, DECEMBER 2013
517
Sandwich fibrin glue technique—Fava et al.
Fig. 2 — Sandwich fibrin glue technique. The components of the fibrin glue are applied sequentially to form a “fibrinogen– conjunctival autograft–thrombin sandwich.”
latter method was used from there on, as it was noted to have several advantages. Outcomes of the 2 techniques were retrospectively compared after a chart review of 56 consecutive eyes with primary pterygia. The conventional group consisted of the first 31 eyes of 24 patients, and the sandwich fibrin glue technique group consisted of the next 25 eyes of 23 patients. All patients were evaluated for Snellen visual acuity, applanation tonometry, and slit-lamp examination at 1 day, 1 to 2 weeks, 6 weeks, and a minimum of 6 months during the postoperative period. Photodocumentation with slit-lamp photography was performed both before and after surgery. Postoperative complications, including graft dehiscence, graft failure, granuloma, dellen, and recurrence were also recorded. Data analysis
with blunt dissection with Westcott scissors matching the conjunctival defect to be covered. This autograft was then placed epithelial side down onto the cornea. In this sandwich fibrin glue technique (Figs. 1 and 2), the components of the fibrin glue were not mixed before application, as is commonly performed in the conventional method, but were kept in separate syringes and applied as follows: (i) the fibrinogen component was first placed onto the bare scleral defect; (ii) the conjunctival autograft was then placed onto the bare scleral defect epithelial side up and positioned to carefully appose the graft to the host conjunctiva; and (iii) once the graft was satisfactorily in position, the second component, thrombin, was applied over the graft and the edges of the graft–host interface. This, in effect, created the fibrinogen-conjunctival autograft-thrombin sandwich. To complete the case, we then removed residual fibrin clot from the fornices. The 6–0 silk corneal suture was then removed. Tobramycin/dexamethasone (TobraDex, Alcon, Fort Worth, Tex.) ointment was instilled into all eyes at the end of the case, and all eyes were patched and shielded. Patients were instructed to use a postoperative regimen of tobramycin/dexamethasone drops 4 times daily in the operative eye for a minimum of 1 month. Mitomycin C was not used in any of these cases. All patients were seen in the clinic the following day after surgery. A video demonstration of the Sandwich Fibrin Glue Technique can be viewed online (Supplementary Video 1). Comparative analysis: conventional versus sandwich fibrin glue technique
The sandwich technique described earlier was compared with the conventional technique of using fibrin glue. In the conventional technique, the fibrinogen and thrombin components of the tissue adhesive were mixed before its application onto the scleral bed and positioning of the conjunctival autograft. The modified technique was noted to be potentially successful after a serendipitous observation during a case planned for the conventional method. The graft was noted to be well adhered intraoperatively after erroneous application of the fibrin glue in a sandwich technique. The
518
Baseline characteristics and visual acuity were compared using a 2-tailed Student t-test (Table 1). Complication rates were compared using the Fischer exact test (Table 2), as the complication rate was found to be low in both groups by creating 2 2 contingency tables for the various complications.
RESULTS In comparing the conventional and sandwich technique groups, both were similar with respect to age, sex, and preoperative and postoperative best corrected visual acuity (Table 1). After treatment, the 2 groups were observed for at least 6 months postoperatively for complications (Table 2). Graft dehiscence was noted on the first postoperative day in 3 eyes in the conventional group only, 1 of which led to graft failure at week 4. Pterygium recurrence was noted in 2 eyes (6.5%) in the conventional group and 1 eye (4.0 %) in the sandwich technique group. None of the values reached statistical significance in comparing the complications between the 2 groups. Table 1—Baseline profile of patients in conventional versus sandwich technique groups
No. of eyes Mean age, y (range) Sex, n (%) Male Female Preoperative BCVA, n (%) 20/20 20/25 to 20/40 20/50 to 20/60 20/70 to 20/100 Postoperative BCVA, n (%) 20/20 20/25 to 20/40 20/50 to 20/60 20/70 to 20/100 Bilateral, n (%) Location Primary
Conventional
Sandwich Technique
pn
31 50.0 (26–74)
25 48.1 (26–77)
NA 0.589
15 (62) 9 (38)
12 (52) 11 (48)
0.450 0.492
9 17 3 2
10 11 4 0
0.391 0.417 0.505 0.218
(29) (55) (10) (6)
13 (42) 15 (48) 3 (10) 0 (0) 7 (30) All nasal All primary
NA, not applicable; BCVA, best corrected visual acuity. n
CAN J OPHTHALMOL — VOL. 48, NO. 6, DECEMBER 2013
2-Tailed Student t-test.
(40) (44) (16) (0)
10 (40) 14 (56) 1 (4) 0 (0) 2 (8.7) All nasal All primary
0.880 0.554 0.395 NA 0.072 NA NA
Sandwich fibrin glue technique—Fava et al. Table 2—Postoperative complications in conventional versus sandwich technique groups Conventional Recurrence, n (%) Graft failure, n (%) Time of occurrence Graft dehiscence Time of occurrence Granuloma, n (%) Time of occurrence Dellen, n (%) Time of occurrence Chemosis, n (%) Time of occurrence Hyperemia/subconjunctival hemorrhage, n (%) Time of occurrence Tearing, n (%) Time of occurrence Pain/photophobia/irritation/ itching, n (%) Time of occurrence Graft edema, n (%) Symblepharon, n (%) Cysts, n (%)
2 (6.5) 1 (3.2) 4 weeks 3 (9.7) 1 day 2 (6.5) 1 week 1 (3.2) 2 weeks 2 (6.5) 1 day, 1 week 4 (13) 1 day 0 (0) 5 (16) 1 day, 1 week 0 (0)
Sandwich Technique
pn
1 (4.0) 0 (0)
1.000 1.000
0 (0)
0.245
3 (12.0) 2, 4 weeks 1 (4.0) 4 weeks 0 (0)
0.647 1.000 0.497
0 (0)
0.120
1 (4.0) 4 weeks
0.446
6 (24)
0.514
1 day, 12 weeks 0 (0)
NA
NA, not applicable. n
Fischer exact test (2-tailed).
DISCUSSION Conjunctival autografting is currently the preferred surgical strategy for the management of primary and recurrent pterygium. The original method2 continues to evolve. Surgical modifications have included small excision,4 the mini-flap technique,11 narrow-strip excision,12 mini-autografting,13 sliding flap,14 rotational autograft,15 and extended excisions.16 Most notably, the use of fibrin tissue glue adhesive has simplified the procedure, leading to shorter surgical time and quicker recovery. Although surgical excision of pterygium with conjunctival autograft itself is a safe and effective procedure with a high success rate, it has been traditionally limited by the time needed to suture the graft in place, as well as suturerelated complications. These include ocular irritation, buttonholes, suture abscesses, granuloma formation, tissue necrosis, and giant papillary conjunctivitis.7 The benefits of fibrin glue adhesives for securing the autograft have been well described. Compared with the traditional suture technique, the use of fibrin glue showed significantly shorter surgical time and decreased postoperative discomfort and pain.4–9 Recurrence rates are also believed to be lower with use of fibrin glue, as reported by long-term follow-up studies.5,9 Srinivasan et al.17 further showed that the degree of inflammation is significantly less with fibrin glue at the 1- and 3-month postoperative visits, while showing comparable graft stability. One possible explanation for the lower rate of recurrence with the use of fibrin glue is thought to be due to the lower degree of postoperative inflammation from decreased tissue manipulation and postoperative irritation.18
When the 2 components are applied simultaneously or sequentially,19 a fibrin clot forms within approximately 30 seconds.4 If the 2 components are mixed before the placement of the autograft, proper positioning must be expedited before polymerization occurs. Some surgeons advocate diluting both glue components to avoid fibrin clot formation before full graft positioning.4,20 In the modified sandwich technique, accurate placement of the autograft is achieved before the second component is administered and a final fibrin seal is formed. This allows the surgeon ample time to attach the graft in its desired position. Graft adherence appears to be as satisfactory as the conventional method. It is unclear whether the thrombin component is interacting with the fibrin at the edges of the graft–host interface or is able to penetrate through the graft. Although the recurrence rate was similar, the modified group did have fewer cases of graft dehiscence. Nevertheless, this was not statistically significant. We found no difference in any of the other parameters studied. This was not unexpected as the conventional technique already shows excellent safety and effectiveness in outcomes. This study does suffer from limitations in that the 2 groups were compared retrospectively versus through a random control trial. With low rates of complications found in this study, there is insufficient power to detect a difference between the 2 techniques. A larger study may confirm a trend toward less graft dehiscence. Future studies could also examine whether this technique may lead to less complications when used by less experienced surgeons or in other procedures where fibrin glue is used. In summary, the sandwich fibrin glue technique described in this study simplifies conjunctival graft gluing by allowing more time to properly position the autograft before fibrin clot formation. It may obviate the need for the timeconsuming practice of diluting the glue components. Recurrence rates were found to be low in both groups of this study.
Online-only material: This article includes online-only material. Supplementary Video 1 can be found on the CJO web site at http://pubs.nrc-cnrc.gc.ca/cjo/cjo.html. It is linked to this article in the online contents of the December 2013 issue. Disclosure: The authors have no proprietary or commercial interest in any materials discussed in this article.
REFERENCES 1. Todani A, Melki SA. Pterygium: current concepts in pathogenesis and treatment. Int Ophthalmol Clin. 2009;49:21-30. 2. Kenyon KR, Wagoner MD, Hettinger ME. Conjunctival autograft transplantation for advanced and recurrent pterygium. Ophthalmology. 1985;92:1461-70. 3. Hirst LW. The treatment of pterygium. Surv Ophthalmol. 2003;48: 145-80. 4. Koranyi G, Seregard S, Kopp ED. Cut and paste: a no suture, small incision approach to pterygium surgery. Br J Ophthalmol. 2004;88: 911-4.
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Sandwich fibrin glue technique—Fava et al. 5. Koranyi G, Seregard S, Kopp ED. The cut-and-paste method for primary surgery: long-term follow-up. Acta Ophthalmol Scand. 2005;83:298-301. 6. Marticorena J, Rodruguez-Ares MT, Tourino R, et al. Pterygium surgery: conjunctival autograft using a fibrin adhesive. Cornea. 2006;25:34-6. 7. Uy HS, Reyes JM, Flores JD, et al. Comparison of fibrin glue and sutures for attaching conjunctival autografts after pterygium excision. Ophthalmology. 2005;112:667-71. 8. Bahar I, Weinberger D, Gaton DD, et al. Fibrin glue versus vicryl sutures for primary conjunctival closure in pterygium surgery: longterm results. Curr Eye Res. 2007;32:399-405. 9. Ratnalingam V, Eu AL, Ng GL, Taharin R, John E. Fibrin adhesive is better than sutures in pterygium surgery. Cornea. 2010;29:485-9. 10. Ang LP, Chua JL, Tan DT. Current concepts and techniques in pterygium treatment. Curr Opin Ophthalmol. 2007;18:308-13. 11. Kim M, Chung SH, Lee JH, Lee HK, Seo KY. Comparison of miniflap technique and conjunctival autograft transplantation without mitomycin C in primary and recurrent pterygium. Ophthalmologica. 2008;222:265-71. 12. Dupps WJ Jr, Jeng BH, Meisler DM. Narrow-strip conjunctival autograft for treatment of pterygium. Ophthalmology. 2006;114: 227-31.
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13. Oguz H, Kilitcioglu A, Yasar M. Limbal conjunctival miniautografting for preventing recurrence after pterygium surgery. Eur J Ophthalmol. 2006;16:209-13. 14. Tomas T. Sliding flap of conjunctival limbus to prevent recurrence of pterygium. Refract Corneal Surg. 1992;8:394-5. 15. Jap A, Chan C, Lim L, Tan DT. Conjunctival autorotation autograft for pterygium: an alternative to conjunctival autografting. Ophthalmology. 1999;106:67-71. 16. Hirst LW. Recurrent pterygium surgery using pterygium extended removal followed by extended conjunctival transplant: recurrence rate and cosmesis. Ophthalmology. 2009;116:1278-86. 17. Srinivasan S, Dollin M, McAllum P, Berger Y, Rootman DS, Slomovic AR. Fibrin glue versus sutures for attaching the conjunctival autograft in pterygium surgery: a prospective observer masked clinical trial. Br J Ophthalmol. 2009;93:215-8. 18. Kheirkhah A, Casas V, Sheha H, Raju VK, Tseng SC. Role of conjunctival inflammation in surgical outcome after amniotic membrane transplantation with or without fibrin glue for pterygium. Cornea. 2008;27:56-63. 19. Panda A, Kumar S, Kumar A, Bansal R, Bhartiya S. Fibrin glue in ophthalmology. Indian J Ophthalmol. 2009;57:371-9. 20. Hovanesian JA, Behesnilian A. Use of fibrin tissue adhesive in conjunctival, corneal, cataract, and refractive surgery. US Ophthalmic Review. 2007;2:42-4.
CAN J OPHTHALMOL — VOL. 48, NO. 6, DECEMBER 2013
Sandwich fibrin glue technique for attachment of conjunctival autograft during pterygium surgery Mark A. Fava, MD, FRCSC,*,†,‡ Catherine J. Choi, MD, MS,*,§ George El Mollayess, MD,¶ Samir A. Melki, MD, PhD*,†,‡ ABSTRACT ● RÉSUMÉ Objective: To report the results of a sandwich application of fibrin glue compared with the standard method of using fibrin glue for the attachment of the conjunctival autograft in pterygium surgery. Participants: The study group consisted of 56 consecutive eyes with primary pterygium. Methods: We performed a retrospective analysis comparing the standard method of using fibrin glue for the attachment of the conjunctival autograft during pterygium excision surgery versus the “sandwich technique.” In the “sandwich technique,” the thrombin component of the fibrin glue was applied after the graft was secured in position over a bed of fibrinogen. Results: Graft dehiscence occurred in 3 eyes in the conventional group only. Recurrence occurred in 2 eyes in the conventional group and 1 eye in the sandwich group. None of the values reached statistical significance. Conclusions: The sandwich technique simplifies conjunctival graft fixation during pterygium surgery with conjunctival autograft by allowing more time to properly position the autograft before fibrin clot formation. Objet : Compte-rendu des résultats d'une application sandwich de la colle fibrine comparativement à la méthode standard d'utilisation de la colle fibrine pour la fixité de l'autogreffe conjonctivale dans la chirurgie du ptérygion. Participants : L'étude a porté sur un groupe de 56 yeux consécutifs ayant un ptérygion primaire. Méthodes : Analyse comparative de la méthode standard d'utilisation de la colle fibrine pour la fixation de l'autogreffe conjonctivale dans la chirurgie du ptérygion comparativement à la « technique sandwich ». Dans la « technique sandwich », la composante thrombine de la colle fibrine était appliquée après que la greffe eut été sécurisée dans une position sur un fond de fibrinogène. Résultats : La déhiscence de la greffe s'est produite dans trois yeux du groupe conventionnel seulement. La récurrence est survenue dans deux yeux du groupe conventionnel et un œil du groupe sandwich. Aucune des valeurs n'avait atteint de signification statistique. Conclusion : La technique sandwich simplifie la fixation de la greffe conjonctivale pendant la chirurgie du ptérygion avec une autogreffe conjonctivale en permettant plus de temps pour positionner correctement l'autogreffe avant la formation d'un caillot de fibrine.
The currently preferred method for the surgical management of primary or recurrent pterygium is excision with conjunctival autograft transplantation.1 This technique was initially described by Kenyon et al.2 in 1985 and has proved to be relatively safe and effective with low rates of recurrence.3 This technique has since undergone many variations, the most notable being the use of tissue adhesives for securing the autograft.4–6 A number of studies have demonstrated the safe and desirable effects of fibrin glue in conjunctival autograft surgeries.7–9 Although widespread in its use, the rapidity with which the fibrin glue forms a clot once the components are mixed can be considered a drawback in the current conventional method. We have examined the clinical outcomes of a modified application method of the fibrin glue compared with this conventional method. In this article, we describe a novel use of the components of fibrin glue,
thrombin and fibrinogen, in a “sandwich” manner allowing more time for graft positioning before clot formation.
From the *Massachusetts Eye & Ear Infirmary; †Beth Israel Deaconess Medical Center, Harvard Medical School; ‡Boston Eye Group; §Harvard Medical School, Boston, Mass.; and ¶American University of Beirut Medical Center, Beirut, Lebanon.
Can J Ophthalmol 2013;48:516–520 0008-4182/13/$-see front matter & 2013 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jcjo.2013.07.004
METHODS We describe 56 consecutive eyes with primary pterygia who underwent pterygium excision with conjunctival autograft with either the sandwich fibrin glue technique or the conventional technique described later. The indications for surgery were the pterygium encroaching onto the visual axis and/or persistent irritation and redness refractory to conservative treatments. The risks and benefits of the procedures were reviewed, and the appropriate operative consents were signed. All patients were operated under monitored assisted care anaesthesia supplemented with a retrobulbar injection of lidocaine 2%
Originally received Jan. 6, 2013. Final revision May 19, 2013. Accepted July 16, 2013 Correspondence to Samir A. Melki, MD, Cornea and Refractive Surgery Service, Massachusetts Eye & Ear Infirmary, 243 Charles Street, Boston, MA 02114; [email protected]
516
CAN J OPHTHALMOL — VOL. 48, NO. 6, DECEMBER 2013
Sandwich fibrin glue technique—Fava et al. (Hospira, Lake Forest, Ill.) and Marcaine (Bupivacaine) 0.75% (APP Pharm, Schaumburg, Ill.). In the operating theater, each patient was prepped and draped in the usual sterile fashion for ophthalmic surgery. Surgical technique: The sandwich fibrin glue technique
The basic technique of pterygium excision and conjunctival autograft harvesting is well described in the literature.3,10 Tisseel fibrin sealant (Baxter Healthcare Corporation, Westlake Village, Calif.) was used as the tissue adhesive in all cases in this study. To aid in positioning of the globe, we placed one 6–0 silk suture through partial-thickness clear cornea, superiorly and
adjacent to the limbus. The head of the pterygium was first removed from its adhesions to the cornea with blunt dissection and, if necessary, a lamellar plane was created with a #57 Beaver blade (MSP, Rincon, Puerto Rico). The pterygium was then undermined using Westcott scissors with clear identification of the medial rectus muscle before excising the body of the pterygium. Underlying Tenon capsule was then grasped with forceps and excised beyond the conjunctival edges. This bare scleral defect was then measured with calipers. Attention was drawn to the superior conjunctiva to fashion a conjunctival autograft first by injecting lidocaine 2% mixed with epinephrine to create a dissection plane between conjunctiva and underlying Tenon capsule. A suitable autograft was then created
Fig. 1 — Outline of the sandwich fibrin glue technique. A, 6–0 silk clear cornea fixation suture allowing for proper positioning of the globe. B, Head of pterygium excised from its corneal adhesions. C, Body of pterygium excised. D, Underlying Tenon capsule excised. E, Subconjunctival injection of 2% lidocaine (arrow) into superior conjunctival donor site, separating conjunctiva from underlying Tenon capsule. F, Conjunctiva dissected from underlying Tenon capsule with blunt dissection using Westcott scissors. G, Conjunctival autograft excised. H, Conjunctival autograft placed epithelial side down onto cornea. I, Tissue adhesive, first component only (fibrinogen), applied to conjunctival defect. J, Conjunctival autograft positioned into defect. K, Tissue adhesive, second component (thrombin), applied to surface of autograft. CAN J OPHTHALMOL — VOL. 48, NO. 6, DECEMBER 2013
517
Sandwich fibrin glue technique—Fava et al.
Fig. 2 — Sandwich fibrin glue technique. The components of the fibrin glue are applied sequentially to form a “fibrinogen– conjunctival autograft–thrombin sandwich.”
latter method was used from there on, as it was noted to have several advantages. Outcomes of the 2 techniques were retrospectively compared after a chart review of 56 consecutive eyes with primary pterygia. The conventional group consisted of the first 31 eyes of 24 patients, and the sandwich fibrin glue technique group consisted of the next 25 eyes of 23 patients. All patients were evaluated for Snellen visual acuity, applanation tonometry, and slit-lamp examination at 1 day, 1 to 2 weeks, 6 weeks, and a minimum of 6 months during the postoperative period. Photodocumentation with slit-lamp photography was performed both before and after surgery. Postoperative complications, including graft dehiscence, graft failure, granuloma, dellen, and recurrence were also recorded. Data analysis
with blunt dissection with Westcott scissors matching the conjunctival defect to be covered. This autograft was then placed epithelial side down onto the cornea. In this sandwich fibrin glue technique (Figs. 1 and 2), the components of the fibrin glue were not mixed before application, as is commonly performed in the conventional method, but were kept in separate syringes and applied as follows: (i) the fibrinogen component was first placed onto the bare scleral defect; (ii) the conjunctival autograft was then placed onto the bare scleral defect epithelial side up and positioned to carefully appose the graft to the host conjunctiva; and (iii) once the graft was satisfactorily in position, the second component, thrombin, was applied over the graft and the edges of the graft–host interface. This, in effect, created the fibrinogen-conjunctival autograft-thrombin sandwich. To complete the case, we then removed residual fibrin clot from the fornices. The 6–0 silk corneal suture was then removed. Tobramycin/dexamethasone (TobraDex, Alcon, Fort Worth, Tex.) ointment was instilled into all eyes at the end of the case, and all eyes were patched and shielded. Patients were instructed to use a postoperative regimen of tobramycin/dexamethasone drops 4 times daily in the operative eye for a minimum of 1 month. Mitomycin C was not used in any of these cases. All patients were seen in the clinic the following day after surgery. A video demonstration of the Sandwich Fibrin Glue Technique can be viewed online (Supplementary Video 1). Comparative analysis: conventional versus sandwich fibrin glue technique
The sandwich technique described earlier was compared with the conventional technique of using fibrin glue. In the conventional technique, the fibrinogen and thrombin components of the tissue adhesive were mixed before its application onto the scleral bed and positioning of the conjunctival autograft. The modified technique was noted to be potentially successful after a serendipitous observation during a case planned for the conventional method. The graft was noted to be well adhered intraoperatively after erroneous application of the fibrin glue in a sandwich technique. The
518
Baseline characteristics and visual acuity were compared using a 2-tailed Student t-test (Table 1). Complication rates were compared using the Fischer exact test (Table 2), as the complication rate was found to be low in both groups by creating 2 2 contingency tables for the various complications.
RESULTS In comparing the conventional and sandwich technique groups, both were similar with respect to age, sex, and preoperative and postoperative best corrected visual acuity (Table 1). After treatment, the 2 groups were observed for at least 6 months postoperatively for complications (Table 2). Graft dehiscence was noted on the first postoperative day in 3 eyes in the conventional group only, 1 of which led to graft failure at week 4. Pterygium recurrence was noted in 2 eyes (6.5%) in the conventional group and 1 eye (4.0 %) in the sandwich technique group. None of the values reached statistical significance in comparing the complications between the 2 groups. Table 1—Baseline profile of patients in conventional versus sandwich technique groups
No. of eyes Mean age, y (range) Sex, n (%) Male Female Preoperative BCVA, n (%) 20/20 20/25 to 20/40 20/50 to 20/60 20/70 to 20/100 Postoperative BCVA, n (%) 20/20 20/25 to 20/40 20/50 to 20/60 20/70 to 20/100 Bilateral, n (%) Location Primary
Conventional
Sandwich Technique
pn
31 50.0 (26–74)
25 48.1 (26–77)
NA 0.589
15 (62) 9 (38)
12 (52) 11 (48)
0.450 0.492
9 17 3 2
10 11 4 0
0.391 0.417 0.505 0.218
(29) (55) (10) (6)
13 (42) 15 (48) 3 (10) 0 (0) 7 (30) All nasal All primary
NA, not applicable; BCVA, best corrected visual acuity. n
CAN J OPHTHALMOL — VOL. 48, NO. 6, DECEMBER 2013
2-Tailed Student t-test.
(40) (44) (16) (0)
10 (40) 14 (56) 1 (4) 0 (0) 2 (8.7) All nasal All primary
0.880 0.554 0.395 NA 0.072 NA NA
Sandwich fibrin glue technique—Fava et al. Table 2—Postoperative complications in conventional versus sandwich technique groups Conventional Recurrence, n (%) Graft failure, n (%) Time of occurrence Graft dehiscence Time of occurrence Granuloma, n (%) Time of occurrence Dellen, n (%) Time of occurrence Chemosis, n (%) Time of occurrence Hyperemia/subconjunctival hemorrhage, n (%) Time of occurrence Tearing, n (%) Time of occurrence Pain/photophobia/irritation/ itching, n (%) Time of occurrence Graft edema, n (%) Symblepharon, n (%) Cysts, n (%)
2 (6.5) 1 (3.2) 4 weeks 3 (9.7) 1 day 2 (6.5) 1 week 1 (3.2) 2 weeks 2 (6.5) 1 day, 1 week 4 (13) 1 day 0 (0) 5 (16) 1 day, 1 week 0 (0)
Sandwich Technique
pn
1 (4.0) 0 (0)
1.000 1.000
0 (0)
0.245
3 (12.0) 2, 4 weeks 1 (4.0) 4 weeks 0 (0)
0.647 1.000 0.497
0 (0)
0.120
1 (4.0) 4 weeks
0.446
6 (24)
0.514
1 day, 12 weeks 0 (0)
NA
NA, not applicable. n
Fischer exact test (2-tailed).
DISCUSSION Conjunctival autografting is currently the preferred surgical strategy for the management of primary and recurrent pterygium. The original method2 continues to evolve. Surgical modifications have included small excision,4 the mini-flap technique,11 narrow-strip excision,12 mini-autografting,13 sliding flap,14 rotational autograft,15 and extended excisions.16 Most notably, the use of fibrin tissue glue adhesive has simplified the procedure, leading to shorter surgical time and quicker recovery. Although surgical excision of pterygium with conjunctival autograft itself is a safe and effective procedure with a high success rate, it has been traditionally limited by the time needed to suture the graft in place, as well as suturerelated complications. These include ocular irritation, buttonholes, suture abscesses, granuloma formation, tissue necrosis, and giant papillary conjunctivitis.7 The benefits of fibrin glue adhesives for securing the autograft have been well described. Compared with the traditional suture technique, the use of fibrin glue showed significantly shorter surgical time and decreased postoperative discomfort and pain.4–9 Recurrence rates are also believed to be lower with use of fibrin glue, as reported by long-term follow-up studies.5,9 Srinivasan et al.17 further showed that the degree of inflammation is significantly less with fibrin glue at the 1- and 3-month postoperative visits, while showing comparable graft stability. One possible explanation for the lower rate of recurrence with the use of fibrin glue is thought to be due to the lower degree of postoperative inflammation from decreased tissue manipulation and postoperative irritation.18
When the 2 components are applied simultaneously or sequentially,19 a fibrin clot forms within approximately 30 seconds.4 If the 2 components are mixed before the placement of the autograft, proper positioning must be expedited before polymerization occurs. Some surgeons advocate diluting both glue components to avoid fibrin clot formation before full graft positioning.4,20 In the modified sandwich technique, accurate placement of the autograft is achieved before the second component is administered and a final fibrin seal is formed. This allows the surgeon ample time to attach the graft in its desired position. Graft adherence appears to be as satisfactory as the conventional method. It is unclear whether the thrombin component is interacting with the fibrin at the edges of the graft–host interface or is able to penetrate through the graft. Although the recurrence rate was similar, the modified group did have fewer cases of graft dehiscence. Nevertheless, this was not statistically significant. We found no difference in any of the other parameters studied. This was not unexpected as the conventional technique already shows excellent safety and effectiveness in outcomes. This study does suffer from limitations in that the 2 groups were compared retrospectively versus through a random control trial. With low rates of complications found in this study, there is insufficient power to detect a difference between the 2 techniques. A larger study may confirm a trend toward less graft dehiscence. Future studies could also examine whether this technique may lead to less complications when used by less experienced surgeons or in other procedures where fibrin glue is used. In summary, the sandwich fibrin glue technique described in this study simplifies conjunctival graft gluing by allowing more time to properly position the autograft before fibrin clot formation. It may obviate the need for the timeconsuming practice of diluting the glue components. Recurrence rates were found to be low in both groups of this study.
Online-only material: This article includes online-only material. Supplementary Video 1 can be found on the CJO web site at http://pubs.nrc-cnrc.gc.ca/cjo/cjo.html. It is linked to this article in the online contents of the December 2013 issue. Disclosure: The authors have no proprietary or commercial interest in any materials discussed in this article.
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