SURGICAL OUTCOMES AND INCIDENCE OF RETINAL REDETACHMENT IN CASES WITH COMPLICATED RETINAL DETACHMENT AFTER SILICONE OIL REMOVAL Univariate and Multiple Risk Factors Analysis MEHMET Y. TEKE, MD,* MELIKE BALIKOGLU-YILMAZ, MD,† PINAR YUKSEKKAYA, MD,* MEHMET CITIRIK, MD,* UFUK ELGIN, MD,* TIMUR KOSE, PHD,‡ FARUK OZTURK, MD* Purpose: To analyze the surgical outcomes and retinal redetachment frequency after silicone oil (SO) removal for complex retinal detachment. Methods: This institutional-based study included 894 consecutive patients who underwent pars plana vitrectomy with SO endotamponade for complicated retinal detachment. The effects of preoperative best-corrected visual acuity, vitreous base shaving, intraoperative scleral buckling, retinectomy, SO viscosity, duration of SO, and vitreous hemorrhage at the first postoperative week on the risk of redetachment were investigated. Results: During a mean follow-up of 39.9 months, anatomical success was not achieved in 118 patients (13.2%) after SO removal. On multivariate analysis, risk factors for recurrent retinal detachment included giant retinal tear (adjusted odds ratio [aOR], 12.39; P , 0.001), high myopia (aOR, 2.70; P = 0.011), surgeries without scleral buckling (aOR, 1.97; P = 0.039), inadequate vitreous base shaving (aOR, 117.62; P , 0.001), and vitreous hemorrhage at the first postoperative week (aOR, 12.13; P , 0.001). Conclusion: Retinal detachment etiology, inadequate vitreous base shaving, lack of intraoperative scleral buckling, and vitreous hemorrhage at the first postoperative week after SO removal were significant risk factors for retinal redetachment after SO removal, but preoperative visual acuity, SO viscosity, and duration of SO had no significant effect on redetachment. RETINA 34:1926–1938, 2014

S

and needed to be removed once the retina was flat. The most important complication of removing the SO has been reported as retinal redetachment.4,7,8 The aim of this study was to evaluate the surgical outcomes and incidence of retinal redetachment after removing SO with multivariate risk factor analysis in 894 Grade C PVR cases.

ignificant improvements in pars plana vitrectomy (PPV) surgery techniques, development of advanced imaging systems, and the introduction of temporary and permanent intravitreal endotamponade materials have contributed to significant progress in the surgery of retinal detachment (RD) complicated by proliferative vitreoretinopathy (PVR). Silicone oil (SO) for endotamponade in the repair of complicated RD was first reported by Cibis et al1 in 1962, and its role in improving retinal reattachment rates has subsequently been supported by others.2–5 The use of SO and the other improvements provide more successful surgical results than the other techniques such as local or 360° buckling, PPV alone, or their combinations. Gonvers6 emphasized that SO was a temporary tamponade

Materials and Methods The study protocol, which adhered to the tenets of the Declaration of Helsinki, was approved by the Institutional Review Board of Diskapi Yildirim Beyazit Training and Research Hospital, Ankara, Turkey. Consecutive patients who underwent PPV with SO 1926

OUTCOMES AFTER SILICONE OIL REMOVAL  TEKE ET AL

tamponade due to complicated RD between March 2000 and September 2012 were retrospectively evaluated in this study. Patients with penetrating and perforating eye injuries, who were on any kind of systemic anti-inflammatory medication, who had history of ocular inflammation, who had coexisting ocular disease or previous intraocular surgery, who developed RD before and during SO removal, and who had a history of intravitreal drug injection were excluded from the study group. All eyes had PVR (Grade C PVR) and had undergone PPV with SO tamponade. The diagnosis and severity of PVR were made according to the classification of the Silicone Study Group.9 Cases were categorized based on various baseline RD risk factors including rhegmatogenous RD, high myopia (defined as refractive error greater than −6.0 D),10 lens status, presence of a giant retinal tear, or recent history of laser-assisted in situ keratomileusis (Table 1). In all cases, 1000 or 5000 cSt SO was used. Twenty-gauge or 23-G 3-port PPV was performed under general or local anesthesia. For standard 20-gauge vitrectomy, a conjunctival peritomy was performed and 3 scleral incisions were made with a 20-gauge stiletto. All incisions were sutured at the end of the procedure. Standard 3 sclerotomies were closed at the end of the procedure with 7.0 vicryl sutures. The 23-gauge PPV was performed with insertion of a cannula using a beveled trocar after displacement of the conjunctiva to misalign purposefully the conjunctival and scleral incisions. No sutures were required to close sclerotomies in patients undergoing 23-gauge PPV. Phacoemulsification and intraocular lens implantation were performed first in the case with cataract precluding view to perform vitrectomy. Posterior hyaloid membrane and vitreoretinal membranes were removed either by peeling or by segmentation or delamination. Relaxing retinotomies/ retinectomies were performed. The decision to perFrom the *Department of Ophthalmology, Ulucanlar Eye Education and Research Hospital, Ankara, Turkey; †Department of Ophthalmology, Dr. Behcet Uz Children Disease and Surgery Training and Research Hospital, Izmir, Turkey; ‡Department of Biostatistics and Medical Informatics, Ege University Faculty of Medicine, Izmir, Turkey. None of the authors have any financial/conflicting interests to disclose. Author contributions: Design of the study (M.Y.T.); Conduct of the study (M.Y.T. and M.B.Y.); Collection (M.Y.T. and P.Y.), management (M.Y.T. and F.O.), analysis (T.K.), and interpretation of the data (M.Y.T., M.B.Y., and T.K.); Preparation (M.Y.T., M.C., and M.B.Y.), review (M.Y.T., M.C., U.E., and F.O.), and approval of the article (M.Y.T. and M.C.). Reprint requests: Melike Balikoglu-Yilmaz, MD, Dr. Behçet Uz Children Disease and Surgery Training and Research Hospital, Department of Ophthalmology, Izmir, Turkey, Basın sitesi mah, 168.sok. No. 18/6, Karabaglar/Izmir, Turkey; e-mail: [email protected]

1927

form relaxing retinotomy was made after maximal removal of membranes had failed to adequately release retinal traction. If retinotomy also failed to relive the retinal contraction, the retinectomy was extended circumferentially to relieve all retinal traction. After flattening the retina, barrier endolaser photocoagulation was applied around the retinal breaks and to the posterior edge of retinotomies/retinectomies. Silicone oil with viscosity of 1000 cSt or 5000 cSt was used. Inferior peripheral iridectomy was performed in aphakic patients. Local or 360° buckling was used additionally in cases with retinal breaks in the inferior retina. Inferonasal subconjunctival antibiotics and corticosteroids were then injected. The criteria for SO removal included complete reattachment of the retina, absence of neovascular proliferations, at least 3 months duration of SO in the eye, complications due to SO such as increased intraocular pressure (IOP), decreased vision due to refractive changes, and emulsification of SO. Additional laser treatment was performed in all patients 3 weeks before silicone removal. Silicone oil was removed through a pars plana sclerotomy and followed by at least three fluid-air exchanges with active aspiration to remove as much residual SO as possible. Most cases were left under a complete air fill; however, some cases were left under gas—either 16% C3F8 or 20% SF6. A 16% C3F8 or 20% SF6 is injected for tamponade; the choice of agent depends on a number of factors. These factors include crystalline lens status, intraoperative mydriasis, posterior capsule opacification, complete peripheral retinal examination under scleral depression, number and size of retinal breaks, and presence of previous PVR. The main indication for using 16% C3F8 is difficult intraoperative visualization, previous PVR, complications during the surgical procedure, and possibility of postoperative hypotony and bleeding occurrence. However, the tamponade was not used in patients with fully reattached and traction-free retina and those patients without risk of hemorrhage after SO removal. The whole peripheral retina was also examined by indentation. Vitreous remnants were detected during a repeat vitrectomy in some patients with redetachment after SO removal. These patients were defined as “inadequate vitreous base shaving.” Intensive vitreous hemorrhage precluding vitreous evaluation in the first week was described as “vitreous hemorrhage at the postoperative 1 week.” The best-corrected visual acuity (BCVA), IOP, anterior, and posterior segment findings of patients were recorded in the follow-up after instillation of SO.

Anatomical Success After Silicone Oil Removal Success (n = 776, 86.8%)

OR (95% CI)

P

Adjusted OR* (95% CI)

P

Total (n = 894)

0.554† 418 (53.9) 67 (56.8) 358 (46.1) 51 (43.2) 50.1 ± 17.1 (5–83) 48.7 ± 16.4 (9–83)

1.13 (0.76–1.66) Reference 0.99 (0.98–1.01)

485 (54.3) 409 (45.7) 49.9 ± 17.1 (5–83)

0.414‡

51 (6.6) 725 (93.4)

6 (5.1) 112 (94.9)

Reference 1.31 (0.55–3.13)

0.538†

57 (6.4) 837 (93.6)

542 (69.8) 234 (30.2)

83 (70.3) 35 (29.7)

1.02 (0.67–1.56) Reference

0.913†

625 (69.9) 269 (30.1)

95 (12.2) 472 (60.8) 206 (26.5) 2 (0.3)

14 (11.9) 74 (62.7) 30 (25.4) —

1.01 (0.51–1.99) 1.08 (0.68–1.70) Reference —

1 (0.1) 39.1 ± 25.5, 32 (12–125) 27.2 ± 16.7, 25 (5–140)

— 44.8 ± 29.4, 34 (12–125) 63.3 ± 28.5, 55 (15–200)

— 1.01 (1.00–1.02)

0.087§

1.07 (1.06–1.08)

,0.001§

0.966† 109 (12.2) 546 (61.1) 236 (26.4) 2 (0.2) 1 (0.1) 39.9 ± 26.1, 32 (12–125) 31.9 ± 22.3, 25 (5–200)



0.570† 726 (93.6) 50 (6.4)

112 (94.9) 6 (5.1)

1.29 (0.54–3.07) Reference

838 (93.7) 56 (6.2)

632 (81.4) 144 (18.6) 1.80 (0.10–2.70)

103 (87.3) 15 (12.7) 2.30 (0.10–2.70)

Reference 1.56 (0.88–2.77) 1.91 (1.22–3.02)

0.003§

12.00 (4–39)

12.00 (4–25)

0.99 (0.94–1.06)

0.801§

700 (90.2) 76 (9.8)

102 (86.4) 16 (13.6)

Reference 1.45 (0.81–2.58)

0.122† 1.27 (0.67–2.42)

735 (82.2) 159 (17.8) 0.462 1.80 (0.10–2.70) 12.00 (4–39)

0.210† 802 (89.7) 92 (10.3)

2014  VOLUME 34  NUMBER 10

Operated eye, n (%) Right eye Left eye Age, mean ± SD (range), years Children (,18 years) Adult ($18 years) Gender, n (%) Male Female Lens status, n (%) Aphakic Phakic Pseudophakic Lens subluxation/ dislocation, drop IOL subluxation/drop Follow-up, mean ± SD, median (range), months The time between the beginning of symptoms and the application, mean ± SD, median (range), days Preoperative macular involvement, n (%) Yes No Retinal tear status, n (%) Single Multiple Preoperative visual acuity, median (range), logMAR Preoperative IOP, median (range), mmHg Preoperative RD status Total, n (%) Retinal breaks in the inferior retina, n (%)

Failure (n = 118, 13.2%)

1928 RETINA, THE JOURNAL OF RETINAL AND VITREOUS DISEASES

Table 1. Univariate and Multiple Logistic Regression Analysis Including Baseline Demographics, Preoperative Visual Acuity, Intraocular Pressure, Axial length, Retinal Detachment Status, Retinal Detachment Etiology, Concomitant Surgical Procedures During Vitrectomy, SO Viscosity and Duration of SO, the Presence of Vitreous Hemorrhage at Postoperative First Week According to Anatomical Success After SO Removal in Eyes With Proliferative Vitreoretinopathy

Table 1. (Continued ) Anatomical Success After Silicone Oil Removal

No With and without scleral buckling and adequate vitreous shaving With scleral buckling, with adequate vitreous shaving With scleral buckling, without adequate vitreous shaving Without scleral buckling, with adequate vitreous shaving Without scleral buckling, without adequate vitreous shaving Permanent tamponade (silicone oil), n (%) 1000 cSt 5000 cSt

Failure (n = 118, 13.2%)

OR (95% CI)

565 (72.8) 96 (12.4) 89 (11.5) 18 (2.3) 8 (1.0)

67 (56.8) 24 (20.3) 14 (11.9) 10 (8.5) 3 (2.5)

Reference 2.11 (1.26–3.53) 1.33 (0.72–2.46) 4.69 (2.08–10.57) 3.16 (0.82–12.21)

65 (8.4) 711 (91.6)

11 (9.3) 107 (90.7)

1.13 (0.58–2.20) Reference

P

Adjusted OR* (95% CI)

P

Total (n = 894)

,0.001† Reference 2.70 (1.25–5.81) 0.011 1.25 (0.47–3.29) 0.654 12.39 (4.36–35.17) ,0.001 5.02 (0.70–36.23) 0.110

632 120 103 28 11

(70.7) (13.4) (11.6) (3.1) (1.2)

0.731† 76 (8.5) 818 (91.5) 0.550† 352 (45.4) 424 (54.6)

57 (48.3) 61 (51.7)

1.13 (0.76–1.66) Reference

409 (45.7) 485 (54.3)

304 (39.2) 472 (60.8)

34 (28.8) 84 (71.2)

Reference 1.59 (1.04–2.43)

11 (1.4)

76 (64.4)

765 (98.6)

42 (35.6)

125.84 (62.22–254.55) Reference

298 (38.4)

15 (12.7)

Reference

6 (0.8)

19 (16.1)

62.91 (21.92–180.54)

25 (2.8)

467 (60.2)

27 (22.9)

1.15 (0.60–2.20)

494 (55.3)

5 (0.6)

57 (48.3)

226.48 (79.17–647.87)

358 (46.1) 418 (53.9)

57 (48.3) 61 (51.7)

1.09 (0.74–1.61) Reference

0.031† ,0.001†

Reference 1.97 (1.03–3.76) 117.62 (54.38–254.41) Reference

,0.001†

0.039 ,0.001

155 (17.3) 739 (82.7) 87 (9.7) 807 (90.3)

313 (35.0)

OUTCOMES AFTER SILICONE OIL REMOVAL  TEKE ET AL

RD etiology, n (%) RRD High myopia Aphakic RD Giant retinal tear After LASIK Retinectomy, n (%) Yes No Combine surgery (phacovitrectomy), n (%) Yes No Scleral buckling, n (%) Yes No Inadequate vitreous base shaving, n (%) Yes

Success (n = 776, 86.8%)

62 (6.9)

0.660†

415 (46.4) 479 (53.6)

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(continued on next page)

19.87 (11.19–35.29) Reference 42 (35.6) 76 (64.4) 21 (2.7) 755 (97.3)

,0.001†

*Adjusted odds ratios were calculated by both forward stepwise (likelihood ratio) and backward stepwise (likelihood ratio) methods. †Pearson chi-square test. ‡t-test. §Mann–Whitney U test. LASIK, laser-assisted in situ keratomileusis; OR, odds ratio; RRD, regmatogenous retinal detachment; IOL, intraocular lens.

12.13 (5.11–28.76) ,0.001 Reference

63 (7.0) 831 (93.0)

5.3 ± 3.8, 4 (3–31) 1.01 (0.96–1.06) 5.5 ± 3.3, 4 (3–30)

Silicone oil duration, mean ± SD, median (range), months Vitreous hemorrhage at the postoperative 1 week, n (%) Yes No

5.3 ± 3.8, 4 (3–31)

0.684‡

Adjusted OR* (95% CI) P OR (95% CI) Failure (n = 118, 13.2%) Success (n = 776, 86.8%)

Anatomical Success After Silicone Oil Removal

Table 1. (Continued )



2014  VOLUME 34  NUMBER 10

Analysis

P

Total (n = 894)

1930 RETINA, THE JOURNAL OF RETINAL AND VITREOUS DISEASES

Statistical analysis was performed using the IBM SPSS 20.0 software (SPSS Inc, Chicago, IL). For the purposes of analysis, qualitative variables were categorized, whereas quantitative data were presented as mean ± standard deviation or median (range). Factors investigated for anatomical success included age, sex, lens status, duration of the SO, macular involvement, the number of the retinal tears, preoperative visual acuity (in logMAR), the location of RD, diagnosis, type of surgery, SO viscosity, duration of SO in the eye, and the presence of vitreous hemorrhage (VH) within the first postoperative week. The multivariate relationship between these factors and anatomical failure was evaluated by logistic regression analysis. However, the Mann–Whitney U or t-test was used for numerical data and chi-square or Fisher’s exact test was used for categorical data in the investigation of the independent effects of these factors on anatomical success. The difference between preoperative, postoperative first day, first month, and first year BCVA of groups with and without anatomical success after SO removal was tested with the Friedman test. The difference between preoperative visual acuity (in logMAR) and that on the follow-up visits and between preoperative and postoperative first month IOP were evaluated with the Wilcoxon signed-rank test. The difference between the groups with and without anatomical success after SO removal in terms of preoperative and postoperative BCVA values was analyzed with the Mann–Whitney U test. P # 0.05 was considered statistically significant. Results Retrospective review yielded 894 eyes of 894 Turkish white patients. The mean age of the 894 patients was 49.9 ± 17.1 years with 625 male cases (69.9%) and 269 female cases (30.1%). The mean follow-up time was 39.9 ± 26.1 (12–125) months. Pars plana vitrectomy surgery was performed in the right eye of 485 patients (54.3%) and in the left eye in 409 patients (45.7%). Of note, 546 eyes (61.1%) were phakic, 109 eyes (12.2%) were aphakic, 236 eyes (26.4%) were pseudophakic, 2 eyes (0.2%) had lens subluxation/dislocation, and 1 eye (0.1%) had IOL subluxation/dislocation. Anterior segment examination was otherwise unremarkable in all of the patients. The preoperative demographic characteristics of the patients are reported in Table 1. According to the statements of patients, the mean duration between the start of the symptoms and presentation at our clinic was 31.9 ± 22.3 days (30–180) days. The macula was involved in 93.7% of the cases, the retina totally detached in 802 (89.7%) patients, and

OUTCOMES AFTER SILICONE OIL REMOVAL  TEKE ET AL

retinal breaks in the inferior retina was present in 92 (10.3%) patients. Of note, 82.8% of the cases had a single tear, 14% of them had 2 tears, and 3.2% of them had 3 tears. A relaxing retinotomy was used in all cases and retinectomies in 76 patients (8.5%). After SO removal, the retina was reattached in 776 patients (86.8%), whereas 118 patients (13.2%) developed redetachment. Presenting visual acuity was hand motion in 71 eyes (60.2%) with retinal redetachment. The macula was involved in 112 eyes (94.9%), and the mean time to presentation was longer than 2 months in 43 eyes (36.4%). Fifty-seven patients (48.3%) accepted reoperation. Epiretinal membrane and/or subretinal membranes were removed, and 5000 cSt SO was injected. Additionally, scleral buckling was performed in 12 eyes (10.2%). After the second surgery, the retina was successfully reattached in 34 eyes (59.6%), and recurrent RD with severe PVR was seen in 23 eyes (40.4%). The mean time to redetachment after SO removal was 6.5 ± 3.4 (1–25) weeks, and 3.4% of redetachment developed within the first 2 weeks. Retinal detachment developed only in 2 patients 4 months later (20 and 25 weeks). The results of univariate analysis are shown in Table 1. No significant relationship was found between the development of RD and the duration of SO in the eye. Vitreous remnants seen at the vitreous base ophthalmoscopically and defined as inadequate vitreous base shaving were observed more commonly in the eyes with recurrent RD (P , 0.001). Adequate vitreous shaving without scleral buckling had no significant risk on anatomical failure in patients who underwent adequate vitreous shaving with scleral buckling (P = 0.675). Vitreous hemorrhage within the first week after the removal of SO was found to be statistically more likely in the cases with redetachment (P , 0.001). The visual acuities at baseline and at the postoperative first day, first month, and first year after SO

1931

removal are presented in Table 2. A difference was found between the groups with and without anatomical success after SO removal in terms of preoperative, postoperative first day, first month, and first year BCVA (P , 0.05, Mann–Whitney U test) (Table 3). Additionally, the differences between the BCVA at baseline and at the postoperative first day, first month, and first year of the two groups were statistically different (P , 0.001, Wilcoxon signed-rank test). Statistically significant difference was also found between the IOP values at baseline and at the postoperative first month IOP (P , 0.001, Wilcoxon signed-rank test). The postoperative complications observed after PPV and SO endotamponade are shown in Table 4. During SO removal, emulsified SO (Figure 1) required anterior chamber lavage in 399 cases (44.6%). YAG iridotomy was performed in 90 eyes (10.1%) (58 phakic [64.4%], 12 aphakic [13.3%], 18 pseudophakic [20.0%], 1 with lens subluxation/dislocation [1.1%], and 1 with IOL subluxation/dislocation [1.1%]) for acute angle closure caused by SO. Synechiotomy was performed in 62 cases (6.9%) where pupil adhesions had developed. Thirty-four pseudophakic patients (3.8%) developed posterior capsule opacification during their follow-up and vitrectomy and capsulectomy were performed in these patients during SO removal. Band keratopathy developed in 21 cases (2.3%). Eight eyes (38.1%) of those that developed band keratopathy had emulsified SO in the anterior chamber. Subconjunctival SO droplets were present in 45 cases (5.0%) (Figure 2). Central retinal artery occlusion occurred in the third month in 1 case (0.1%) (Figure 3). Subretinal perfluorocarbon liquid was also observed in 1 case (0.1%) (Figure 4). After removal of SO, 18 cases of Phthisis bulbi (2.0%) were observed. These cases were young patients (range, 34–41 years) who had postoperative anterior PVR and were not followed up regularly because of personal reasons. Patients could be seen in postoperative first

Table 2. Distribution of Visual Acuity at Baseline and Postoperative First Day, First Month, and First Year After SO Removal

Not evaluated* No LP LP† HM† 50 cm–5 m CF† 0.1–0.5† 0.6–1.0†

Preoperative VA

Postoperative First Day VA

Postoperative First Month VA

Postoperative First Year VA

4 (0.4) 0 (0.0) 8 (0.9) 417 (46.6) 411 (46.0) 46 (5.1) 8 (0.9)

5 (0.6) 0 (0.0) 5 (0.6) 90 (10.0) 787 (88.0) 7 (0.8) 0 (0.0)

0 (0.0) 0 (0.0) 0 (0.0) 4 (0.4) 317 (35.5) 562 (62.9) 11 (1.2)

0 (0.0) 18 (2.0) 0 (0.0) 2 (0.2) 286 (32.0) 573 (64.1) 15 (1.7)

Values are indicated as n (%). *means unconscious patients and/or children to whom visual acuity could not be performed. †Visual acuity indicates as Snellen lines. CF, counting fingers; HM, hand motion; LP, light perception; VA, visual acuity.

1932 RETINA, THE JOURNAL OF RETINAL AND VITREOUS DISEASES



2014  VOLUME 34  NUMBER 10

Table 3. Postoperative Visual Acuities and Intraocular Pressure 1 Month After SO Removal in Eyes With Proliferative Vitreoretinopathy Anatomical Success After Silicone Oil Removal Success (n = 776; 86.8%) Postoperative 1 day VA (logMAR) Postoperative 1 month VA (logMAR) Postoperative 1 month IOP (mmHg) Postoperative 1 year VA (logMAR)

Failure (n = 118; 13.2%)

P

Total (n = 894)

1.75 ± 0.26, 1.80 (1.00–2.70) 1.83 ± 0.30, 1.80 (1.10–2.70)

0.008*

1.76 ± 0.26, 1.80 (1.00–2.70)

0.80 ± 0.31, 0.70 (0.15–2.30) 1.31 ± 0.24, 1.30 (0.70–2.30)

,0.001*

0.87 ± 0.35, 1.00 (0.15–2.30)

16.31 ± 6.37, 14.00 (1–47)

16.27 ± 5.73, 15.00 (8–34)

0.81 ± 0.41, 0.70 (0.15–3.00) 1.33 ± 0.46, 1.20 (0.30–3.00)

0.622* ,0.001*

14.55 ± 1.21, 15.00 (4–42) 0.88 ± 0.45, 1.00 (0.15–3.00)

Values are indicated as mean ± SD, median (range). *Mann–Whitney U test. VA, visual acuity.

year. Transient hypotony was observed at the first postoperative day in 55 (6.2%) cases who underwent 23-G PPV. The IOP in these cases normalized within 2 weeks. The IOP was controlled with medical treatment in 116 cases (13.0%) with prolonged IOP elevation after SO removal. Fourteen patients (1.6%) in whom IOP could not be controlled with medical treatment underwent filtering surgery. Fifteen painful phthisical eyes (1.7%) with no light perception in which the surgeries were not successful were enucleated. Multiple logistic regression analysis (forward stepwise method) of preoperative visual acuity, RD etiology, scleral buckling, adequacy of vitreous base shaving, and

the occurrence of VH within the first week after SO removal revealed inadequate vitreous base shaving to be the most important factor. The presence of VH within the first postoperative week was found to be the second most important variable. Retinal detachment etiology and scleral buckling were the third and fourth variables to be included in the model. Preoperative visual acuity was not found to be of significance to be included in the regression model (P = 0.462). Additionally, a relationship was found between lower anatomical success and inadequate vitreous base shaving (adjusted odds ratio [aOR], 117.62; 95% confidence interval [CI], 54.38– 254.41; P , 0.001), vitreous hemorrhage development

Table 4. Complications Due to the SO Used as Endotamponade Anatomical Success After Silicone Oil Removal Complications, No. (%) Emulsified SO requiring anterior chamber washout Controlled glaucoma with medical treatment YAG iridotomy due to the development of acute angle closure Floaters after silicone instillation Synechiotomy of pupillary adhesion Hypotonia Subconjunctival silicone droplets Posterior capsule opacification Band keratopathy Phthisis bulbi Enucleation Uncontrolled glaucoma underwent to drainage surgery Central retinal artery occlusion Subretinal perfluorocarbon liquid *Pearson Chi-square test. †Fisher’s exact test.

Success (n = 776; 86.8%)

Failure (n = 118; 13.2%)

340 (43.8) 103 (13.3) 79 (10.2)

59 (50.0) 13 (11.0) 11 (9.3)

55 55 46 39 29 13 12 9 11

(7.1) (7.1) (5.9) (5.0) (3.7) (1.7) (1.5) (1.2) (1.4)

1 (0.1) —

9 7 9 6 5 8 6 6 3

P

Total (n = 894)

0.208* 399 (44.6) 0.497* 116 (13.0) 0.773* 90 (10.1)

(7.6) (5.9) (7.6) (5.1) (4.2) (6.8) (5.1) (5.1) (2.5)

0.832* 0.645* 0.474* 0.978* 0.791* 0.001* 0.011* 0.002* 0.359*

— 1 (0.8)

1.000† 0.132†

64 62 55 45 34 21 18 15 14

(7.1) (6.9) (6.2) (5.0) (3.8) (2.3) (2.0) (1.7) (1.6)

1 (0.1) 1 (0.1)

OUTCOMES AFTER SILICONE OIL REMOVAL  TEKE ET AL

1933

Fig. 1. The “reverse hypopyon” appearance of emulsified silicone in the anterior chamber.

in the first postoperative week (aOR, 12.13; 95% CI, 5.11–28.76; P , 0.001), RD etiology (high myopia [aOR, 2.70; CI 95%, 1.25–5.81; P = 0.011], giant tear [aOR, 12.39; 95% CI, 4.36–35.17; P , 0.001]), and no scleral buckling (aOR, 1.97; 95% CI, 1.03–3.76; P = 0.039) (Table 1). Discussion Silicone oil tamponade is a standard approach in the treatment of complicated RD and is used after the release of fixed retina in complicated RD and PVR to ensure functional retinal reattachment and recovery.11–15 The Silicone Study Group suggested that SO was more effective than SF6 but approximately equivalent to C3F8 in cases of severe PVR.13,16 However, the incidence of complications such as glaucoma, cataract, and keratitis increases because of the longer duration of SO in the eye and hypotony and recurrent RD may develop at a rate of 8%–40% after SO removal.7,17–21

Fig. 2. Subconjunctival silicone oil granuloma.

Fig. 3. Color fundus photographs of a patient with central retinal artery occlusion occurring 3 months after SO instillation reveals retinal whitening and a cherry-red spot (A). Repeat photographs 1 month later (B) reveal optic atrophy associated with a final visual acuity of hand motion.

The rate of retinal redetachment after the removal of SO was reported to be 0%–32% in several studies because of different confounding factors including ethnic, socioeconomic, and access to health care.8,17 The Silicone Study Group reported a retinal redetachment rate of 20% after SO removal in PVR-C3 and worse cases.18 Choudhary et al22 reported a redetachment rate of 3.46% in their study with 173 cases and stated that aggressive vitreous base shaving, performing retinotomy, filling the eye with SO for full tamponade, and performing argon laser would reduce the complication rate. Jonas et al23 reported 225 cases including 185 PVR cases and 40 patients with proliferative diabetic retinopathy and RD. The retinal redetachment rate approximately 10 months after the removal of SO was 25.3% in cases with complicated RD with a history of previous unsuccessful surgery.23 The same study reported retinal redetachment to be associated with previous unsuccessful surgeries, reduced visual acuity, inadequate vitreous base shaving, absence of buckling in cases with PVR,

1934 RETINA, THE JOURNAL OF RETINAL AND VITREOUS DISEASES

Fig. 4. Color fundus photograph (A) and corresponding macular optical coherence tomography (B) of retained subfoveal perflourocarbon liquid revealing two well-circumscribed bubbles.

and the absence of inferior retinotomy.23 Additionally, they reported that the technique of SO removal and the duration of SO in the eye were not statistically significant for retinal redetachment.23 In this study, SO removal was performed through the pars plana sclerotomy site in all of our cases. Therefore, the effect of the silicone removal technique on the retinal redetachment could not be evaluated. In addition, all of our cases had undergone vitreoretinal surgery for the first time, therefore the effect of previous failed interventions could not be evaluated. However, SO viscosity and duration of SO were found not to be related to retinal redetachment. Previous studies have examined the effect of myopia on anatomical success. Scholda et al24 reported a higher retinal redetachment rate after SO removal in myopic eyes, whereas Jonas et al23 reported no difference in the rate of redetachment in high myopic eyes. In our study, RD etiology was detected to be related to RD development. Additionally, the retinal redetachment rate after SO removal was found to be 2.1 times higher in the high myopic RD group than that of the rhegmatogenous RD group. The timing of SO extraction ranges from 2 to 13 months in various studies.12,18,23,25–27 Studies have revealed that SO removal time has no effect on anatom-



2014  VOLUME 34  NUMBER 10

ical success.8,12,22,26,28 Our study revealed a mean duration of SO of approximately 4 months, and we found no statistically significant relationship between the timing of SO removal and anatomical success. Another result of our study was that the viscosity of SO was not predictive of anatomical success. Silicone oil should be removed when the retina is anatomically and functionally stable. However, redetachment of the retina after SO removal can develop as a result of reopening of the preexisting hole that had been tamponaded with SO, progression of a occult detachment, or formation of a new hole due to ongoing traction.18 Inadequate vitreous base shaving was found to be an important factor particularly in the development of recurrent RD in areas of peripheral retinal degeneration. Therefore, we recommend complete shaving of the vitreous base. Choudhary et al22 recommended that the vitreous base needs to be shaved aggressively. Jonas et al23 reported the incidence of redetachment after the removal of SO to be more frequent in patients with an inadequate vitreous base shaving. The vitreous base was not shaved adequately in 9.7% of the eyes in our study. Obstacles to complete vitreous base shaving included previous complicated cataract surgery, pupillary synechiae, residual lens cortex, inadequate pupillary dilation, posterior capsular opacification, and the possibility of lens injury in phakic patients. Additionally, the lack of chandelier illumination and an ultra-high speed cutting rates may have further impeded more aggressive vitreous shaving. Vitreous hemorrhage after the removal of SO was also found to be an important risk factor for recurrent RD. Close follow-up of the patients with postoperative VH is important because of the possibility of its coexistence with RD. Jonas et al23 reported a significantly higher incidence of mild-to-moderate VH within the first 3 days after SO removal in patients with postoperative RD development than those without. In our study, the VH incidence within the first postoperative week was significantly greater in cases with redetachment. We detected intensive vitreous hemorrhage after SO removal with severe PVR cases. Proliferative vitreoretinopathy can be thought of as a reparative or scarring mechanism. Proliferative vitreoretinopathy is characterized by stiffening and folding of the retina, progressing to a funnel RD that is immobile. Therefore, we interpreted this situation as VH associated with recurrent RD rather than a new break and blood itself increases the risk of PVR. Jonas et al23 reported in their study that the postoperative RD is significantly more frequent in cases without an encircling band and inferior retinotomy when they compared cases with inferior retinotomy with or without encircling. However, Lam et al28 reported

Table 5. Summary of Previous Literature Regarding Risk Factors for Retinal Redetachment After Silicone Oil Removal

Publication Choudray et al22

Year

Location

2012 Pakistan

No. Patients

Mean Age (Years)

M

F

History of Previous Vitrectomy

173

47

121

52

+

Mean SO Duration 70 ± 48 weeks (2–256 weeks)

SO Viscosity (Centistokes) 5000

Mean Follow-up Period After SO Removal At least three months

Overall Anatomical Success Rate (%) 96.5

2008 Hong Kong

147

52.6 ± 15.5

92

55

+

12.4 ± 9.8 months (6.0–26.0 months)

1300

22.1 ± 18.7 months (6.0–71.0 months)

81.6

Goezinne et al31

2007 The Netherlands

287

56.6 ± 14.8 199

88

+

10.0 ± 6.9 months

1000

21.2 ± 16.6 months

81

Laidlaw et al27

2002 England, United Kingdom

Jonas et al23 2001 Germany

376

225

55.4 ± 17.2 245 131

51.6 ± 18.5 137

88

+

+

142 days* (14–889 days)

10.2 ± 10.4 months (6.8 months*) (1–83 months)

NS

5000

272 days* (10–1522 days)

17.4 ± 14.4 months (3.0–67.4 months)

76.3

74.7

Lack of aggressive removal of the vitreous base Lack of retinotomies Not ensuring complete SO filling for adequate tamponade Lack of argon retinopexy Increased number of previous unsuccessful RD surgeries Longer axial lengths Male sex Presence of preoperative Rubeosis PDR Lack of prophylactic laser retinopexy Need for retinal reattachment surgery subsequent to a first SO procedure Number of previously unsuccessful RD surgeries

(continued on next page)

1935

Surgeon

OUTCOMES AFTER SILICONE OIL REMOVAL  TEKE ET AL

Lam et al28

Risk Factors Associated With a Lower Anatomical Success Rate

Publication

Bassat et al26 This study

Year

Location

2000 Israel 2013 Turkey

No. Patients

67 894

Mean Age (Years)

47.4 ± 21.3

M

46

F

(Continued )

History of Previous Vitrectomy

21

+

49.9 ± 17.1 625 269

−

Mean SO Duration

11.7 ± 5.9 months 5.3 ± 3.8 months (3–31 months)

SO Viscosity (Centistokes)

1000 1000 and 5000

Mean Follow-up Period After SO Removal

Overall Anatomical Success Rate (%)

Risk Factors Associated With a Lower Anatomical Success Rate

15 months

91.2

Visual acuity before SO removal Incomplete removal of vitreous base Absence of an encircling band Indication for PPV Eyes with PVR

39.9 ± 26.1 months (12–125 months)

86.8

RD etiology (giant retinal tear and high myopia)

2014  VOLUME 34  NUMBER 10

*Values are presented as median. NS, not stated; PDR, proliferative diabetic retinopathy.



Inadequate vitreous base shaving Lack of intraoperative scleral depression Vitreous hemorrhage at the first postoperative week after SO removal

1936 RETINA, THE JOURNAL OF RETINAL AND VITREOUS DISEASES

Table 5.

OUTCOMES AFTER SILICONE OIL REMOVAL  TEKE ET AL

previously performed scleral buckling surgery not to have a statistically significant relationship with anatomical success after SO removal. Choudhary et al22 reported that the redetachment rate in their series was low (3.46%) because they have performed retinotomy in all cases. In our study, we performed relaxing retinotomy in all cases and retinectomy and scleral buckling in cases with retinal breaks in the inferior retina. Jonas et al25 reported that RD developed during 2 days to 5.5 months after SO removal. The rate of RD development gradually decreased in the period after the removal of the SO and was uncommon after 5.5 months. They stated that 75% of detachments occurred within the first 50 days.25 Another study revealed 66% of the detachments within the first 50 days, but in 2 cases, RD developed 5.5 months later.27 We found RD development after SO removal to be within the first 2 months in 83.9% of the cases (maximum 5.5 months). Various studies report an improvement in BCVA in patients with an attached retina after removal of the SO.12,18,22–24,29 Zilis et al30 suggested the improvement in BCVA after removal of the SO being caused by several reasons such as the refractive changes and probable retinal toxicity because of the SO and the visual acuity being increased by the gradual healing of the reattached retina. Similarly, in our study, the improvement in BCVA at the postoperative first day and first year after removal of the SO was observed. There are several limitations in our study. First, the study was retrospective. Second, SF6 and C3F8 administration after SO removal were not randomized. Third, the effect of the vitrectomy type (20-G or 23-G) on retinal redetachment could not be assessed. The strong aspect of our study was that it includes a large series of patients with long follow-up period as summarized in Table 5. In conclusion, inadequate vitreous base shaving, the occurrence of vitreous hemorrhage at the first postoperative week after SO removal, the detachment etiology, and lack of scleral buckling were significant prognostic factors on retinal redetachment after SO removal. Preoperative visual acuity, the viscosity of SO, and the duration of SO were not found to be associated with recurrent RD after SO removal. Moreover, the use of SO as tamponade in complicated cases, individualized SO removal time and evaluating redetachment in first 2 months after operation might improve the anatomical and functional success rates. Key words: pars plana vitrectomy, proliferative vitreoretinopathy, retinal detachment, silicone oil removal.

1937

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