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ORIGINAL ARTICLE
Year : 2020  |  Volume : 23  |  Issue : 3  |  Page : 337-342

Outcome of vitrectomy for advanced proliferative vitreoretinopathy complicating primary rhegmatogenous retinal detachment among Nigerians


Department of Ophthalmology, Eye Foundation Hospital; Eye Foundation Retina Institute, 27 Isaac John Street, GRA, Ikeja, Lagos, Nigeria

Date of Submission20-Mar-2019
Date of Acceptance14-Dec-2019
Date of Web Publication5-Mar-2020

Correspondence Address:
Dr. O N Okonkwo
Eye Foundation Retina Institute, 27 Isaac John Street, GRA, Ikeja, Lagos
Nigeria
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/njcp.njcp_158_19

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   Abstract 


Aim: To present the anatomical and visual outcome and compare different techniques in the surgical treatment of proliferative vitreoretinopathy (PVR) in Nigerians.Method: Comparative retrospective review of PVR grade C and D eyes that had vitreoretinal surgery with silicone oil between April 2005 and December 2012. Data was extracted from consecutive case notes after exclusion of eyes with PVR associated with proliferative diabetic retinopathy (PDR), proliferative sickle cell retinopathy (PSCR) and eyes with nonuse of silicone oil. A comparison of the outcome of vitrectomy alone (Vit.), versus combined with a scleral buckle (Vit.+SB), versus with retinectomy (Vit.+RT), versus with all three procedures (Vit.+SB+RT) was done. Statistical analysis was done using the Statistical Package for Social Sciences version 16 software. Pearson Chi-square test and Fisher's exact T-test were used to determine the effect of relationships. Results: 138 eyes of 138 patients had grades C (100 eyes) and grade D (38 eyes) PVR. Surgery involved vitrectomy and membrane peel in 53% of eyes, additional scleral buckle in 22%, and retinectomy was performed in 17%. Retinal reattachment rate was 86% for PVR C eyes and 87% in PVR D eyes. There was no statistically significant difference in anatomical outcome between vitrectomy alone and the combination surgeries. In the vitrectomy only category, the postoperative vision was noted to improve (> preoperative), in 48% of PVR C and in 31% of PVR D. 33% of PVR C and 44% of PVR D eyes had a worse vision (< preoperative). Visual outcome was similarly poor in the combination surgeries with improved vision noted in 12%, 44%, and 33% of the Vit.+SB, Vit. +RT, and Vit.+SB+RT PVR C eyes, respectively. In PVR D eyes, improved vision was seen in 57% and 12% of Vit.+SB and Vit.+RT eyes, respectively. Conclusion: Surgery results in anatomical reattachment and there is nonsuperiority of any technique. Visual outcome is poor as previously reported. Recent trials of pharmacological adjuncts may show promise for improved visual outcomes.

Keywords: Proliferative vitreoretinopathy, retinectomy, scleral buckle, silicone oil, vitrectomy


How to cite this article:
Okonkwo O N, Hassan A O, Oderinlo O. Outcome of vitrectomy for advanced proliferative vitreoretinopathy complicating primary rhegmatogenous retinal detachment among Nigerians. Niger J Clin Pract 2020;23:337-42

How to cite this URL:
Okonkwo O N, Hassan A O, Oderinlo O. Outcome of vitrectomy for advanced proliferative vitreoretinopathy complicating primary rhegmatogenous retinal detachment among Nigerians. Niger J Clin Pract [serial online] 2020 [cited 2020 Apr 7];23:337-42. Available from: http://www.njcponline.com/text.asp?2020/23/3/337/280019




   Introduction Top


Proliferative vitreoretinopathy (PVR) is a well-described complication of rhegmatogenous retinal detachment (RRD). Despite improvements in surgical techniques, PVR remains the most important reason for failure of a retinal reattachment surgery and is a poor prognostic feature.[1],[2] Preoperative PVR is a risk factor for the occurrence of postoperative PVR and is associated with poor visual outcome.[1],[2] It is estimated to be responsible for 75% of primary surgical failures and is, therefore, a significant problem for the vitreoretinal surgeon.

PVR occurs due to the migration and proliferation of cellular elements including retina pigment epithelium (RPE) and glial cells.[1],[2],[3] This cellular proliferation results in membranes forming on the retinal surface (preretinal) and underneath the retina (subretinal) position and some components occur within the retina. Contraction of these membranes leads to foreshortening of the retina, traction, reopening of old retina breaks or creation of new breaks, and often recurrent retina detachment.[3] Reports of PVR in Africa appear to be significantly higher than reported in the more developed countries and may be related to delay in presentation of the patients.[4]

PVR often presents as a complex retinal detachment (RD) situation and requires vitreoretinal surgical intervention. Techniques employed include vitrectomy with peeling of epiretinal and subretinal membranes, placement of an external scleral buckle, and in several cases a relaxing retinectomy technique is required to achieve reattachment of the more posterior retina. These techniques are aimed at relieving the traction induced by the PVR process. Silicone oil is often used, as a long-term tamponade in such cases and hypotony is not unusual in several cases. The visual prognosis of surgery for PVR is generally known to be poor and less than a third of eyes have vision 6/60 or better. The outcome of this vitreoretinal intervention among Nigerians living in sub Saharan African has not been reported. Therefore, the aim of this study is to evaluate the outcome of surgery for PVR stages C and D. Also, to compare outcomes of vitrectomy (V) alone, with the combination surgery, that is, with the use of a scleral buckle (SB), with a retinectomy (R), and finally using all three techniques.


   Patients and Methods Top


The study was a retrospective cross-sectional case series using consecutive eyes diagnosed to have RRD complicated by PVR grades C or D, (as documented in the case record and Operating Room (OR) logbook and who had vitrectomy surgery with silicone oil endotamponade between April 2005 and December 2012. All patients selected had advanced PVR grades C and D RRD at presentation. None of the cases had undergone previous surgery for retinal detachment. Exclusion criteria include previous retinal surgery, proliferative disease resulting from diabetic retinopathy, sickle cell retinopathy, trauma, and nonuse of silicone oil. All patients had surgery using 20G instrumentation and Accurus vitrectomy system (Alcon, USA). An informed consent was obtained from each patient and properly documented prior to surgery. The clinical diagnosis of RRD with PVR was made after clinical examination involving a Snellen visual acuity testing, intraocular pressure measurement, pupillary examination, slit-lamp examination of the anterior segment, and a dilated fundus examination (a combination of 1% tropicamide and 2.5% phenylephrine was used routinely for pupillary dilatation). The fundus examination took into account the nature of the retinal detachment; presence of retinal break, number of quadrants of retinal detachment, and the stage of PVR C or D were indicated. The classification of PVR used was as by the retina society terminology committee.[5],[6]

As this was a retrospective study, there was no standardization of surgery done; each surgeon employed the technique judged to be most suitable at his discretion. Perfluorocarbon liquid (heavy liquid) was in use at the department for such PVR surgery and silicone oil was used as a long-acting tamponade at the conclusion of surgery. Postoperatively, patients were seen on day one, week one, month one and at a subsequent clinic visit. The postoperative parameters used for this manuscript was the findings at the patients' last visit as recorded in the case records. All patients had a minimum of 6 months follow-up. During the clinic visits, Snellen visual acuity, intraocular pressure assessment, slit-lamp anterior segment examination, and dilated retina examination to assess retina attachment status were performed.

Ethical approval was sort from the institutional review board, but was waived as the study only involved the retrospective review of the patient's clinical records. This research was conducted in compliance with the ethical standards as laid out by the Helsinki declaration.

Data analysis: Data obtained were analyzed using the Statistical Package for Social Sciences (SPSS) version 16 software. Frequency tables and charts were used for data summarization and presentations for qualitative data (age group, type of surgeries, retinal outcome). Cross tabulations were done using Pearson Chi-square test to determine the effect of relationship and Fisher's exact T-test was used in place of Pearson in cases when the number of cases is less than five in each cell or less than 20 in all the cells put together. Two-tailed statistical significant level was put at P values < 0.05.


   Results Top


One hundred and thirty-eight eyes of 138 patients (clinical notes) had vitrectomy surgery for advanced PVR RD and met the study inclusion criteria out of 944 eyes that had vitrectomy in the department (this accounts for approximately 14.6% of total vitrectomy surgery done within the 7 year study period). The age group of the patients was between 9 and 72 years with a median age of 50 years (mean age 44.7 ± 15.7 years). There were 105 males (76%) and 33 females (24%) with a male to female ratio of 3.2: 1

There were higher numbers of PVR grade C (73%). Also, more left eye (53%) and approximately 20% of eyes had a giant retinal detachment, while two-thirds of eyes had a total retinal detachment involving all four quadrants of the retina. Details are shown in [Table 1].
Table 1: Preoperative PVR categorization, laterality, giant tear, and quadrantic affectation

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A review of the distribution of various surgical options revealed that the surgical options used include vitrectomy with membrane peel alone, vitrectomy with scleral buckle (Vit + SB), vitrectomy with retinectomy (Vit + RT), and vitrectomy with scleral buckling and retinectomy (Vit + SB + RT). The frequency of use of each option among the number of study eyes is shown in [Figure 1]. Vitrectomy alone was the technique of choice in more than half of the patients, accounting for 53% of the surgeries done. This was followed by vitrectomy with the application of a scleral buckle in 22% of the eyes and vitrectomy with retinectomy in 17%. Vitrectomy with scleral buckle and retinectomy was done in only 7% of eyes, which were all PVR C eyes.
Figure 1: Surgical techniques. This shows the categories of retinal reattachment surgeries performed on the 138 patients. Key: Vit: Vitrectomy. SB: Scleral Buckle. RT: Retinectomy

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The anatomical retina reattachment rate was 86% for PVR C and 87% for PVR D. The statistical analysis showed that surgical intervention significantly improved the anatomical outcome of the eye as P value was 0.0005 for each PVR group.

Further outcome analysis was done comparing the anatomical outcome and visual outcome of the other 3 combination surgery options to vitrectomy alone for the 100 eyes with PVR C. This is shown in [Figure 2].
Figure 2: Postoperative anatomical retinal outcome among 100 PVR grade C eyes. Key: Vit: Vitrectomy. SB: Scleral Buckle. RT: Retinectomy. Key # = P values

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[Figure 2] reveals that vitrectomy only and Vit + SB + RT recorded the highest percentages of flat or attached retina (90% and 89%, respectively). However, when compared with the other surgical options, no statistically significant difference in the retinal reattachment outcome between vitrectomy alone and the other combination surgeries was found (all P values were > 0.05)

The visual outcomes were categorized based on a comparison between preoperative vision and postoperative vision in the surgery eye at the last follow-up visit into “improved vision” if the post operative vision was better, “worse vision” if the postoperative vision was poorer, and “same vision” if there was no change. Improved visual outcome was noted in a higher percentage (48%) of the vitrectomy alone compared to the other 3 combination surgeries. However, no statistically significant difference in the visual outcome between vitrectomy alone and combination surgeries was found (all P values were >0.05). This is illustrated in [Figure 3].
Figure 3: Postoperative visual outcome among 100 PVR grade C eyes. Key: Vit: Vitrectomy. SB: Scleral Buckle. RT: Retinectomy. Key # = P value

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In those cases with PVR D, flat or attached retina was more in patients who had Vit + SB. Similar to PVR C eyes, no statistically significant difference in the anatomical retinal outcome between vitrectomy alone and combination surgeries was found (all P values were >0.05). This can be seen in [Figure 4].
Figure 4: Postoperative anatomical retinal outcome among 38 PVR grade D eyes. Key: Vit: Vitrectomy. SB: Scleral Buckle. RT: Retinectomy

Click here to view


Improvements in visual acuity were more in the Vit + SB group. However, no statistically significant difference in the visual outcome between vitrectomy alone and the other combination surgeries was seen (all P values were >0.05). This can be seen in [Figure 5].
Figure 5: Postoperative visual outcome among 38 PVR grade D eyes. Key: Vit: Vitrectomy. SB: Scleral Buckle. RT: Retinectomy

Click here to view


Furthermore, an analysis was performed on other presenting RD features including the presence of a giant retina tear, pre and postoperative intraocular pressure and number of quadrants of RD, to determine if there was a significant contribution of these clinical features to anatomical outcome. There were 17 giant retinal tears of the 100 PVR C eyes and 10 giant retinal tears of the 38 PVR D eyes. In both PVR C and D amongst giant retinal detached eyes, anatomical reattachment was 13/17 (76%) and 10/10 (100%), respectively. This suggests that giant retinal tears can be reattached with a considerable high degree of success despite presence of advanced PVR. Comparing the anatomical outcome in eyes with GRT versus those eyes without GRT, there was no statistical difference P = 0.252 and 0.069 for PVR C and D, respectively.

Historically low intraocular pressure has been associated with preoperative PVR presentation and especially postoperative PVR. In this study, we did not find any significant difference in anatomical reattachment rates between eyes having an IOP of < or equal to 6 mmHg and eyes >6 mmHg. The reattachment rate was 84% if IOP was equal to <6 mmHg and 87% if >6 mmHg (P value 0.4 and 1.0 for PVR C and D, respectively). Postoperative IOP was >6 mmHg in 69.5% of total number of anatomically attached eyes, and < or equal to 6 mmHg in 21.5% of attached eyes. However, 50% of postoperative detached eyes had IOP of < or equal to 6 mmHg, while another 50% had an IOP >6 mmHg. The Odd Ratio (0.638 and 0.30) indicates that an anatomical flat retina reduces the risk of developing hypotony by 64% and 30% for PVR C and D, respectively.

Preoperative number of quadrants of detached retina [Table 1] did not appear to influence the anatomical reattachment rate, which was 100% for 1 and 2-quadrant affectation, 97.5% for 3 quadrants, and 84.5% for 4 quadrants (total RDs).


   Discussion Top


Several studies have confirmed the hypothesis that PVR occurs as a reparative process induced by retinal breaks and an excessive inflammatory reaction. There are well-known risk factors for the occurrence of PVR, which include large retinal breaks (e.g. giant retina tears, multiple large breaks), ocular inflammation, preoperative or postoperative choroidal detachment, excessive cryotherapy, vitreous hemorrhage, preoperative PVR, and large detachments greater than two quadrants.

PVR poses a significant vitreoretinal problem in Africa as evidenced by reported higher rates in the region. The incidence of PVR among a group of Nigerians with giant retinal tears has been reported as 83%.[7] In our study of 618 vitrectomies for RRD, 33% of eyes had some degree of PVR, and significant grade PVR C and D was seen in 16.5% of eyes.[8] A similar study from South Africa reported PVR in 33% of the eyes,[9] while from east Africa PVR rate was 17.5%.[10] Significant PVR rates appear to be highest in a study from Ethiopia, at 69%.[4] PVR rates in the sub Saharan Africa, therefore, are in the double digits contrary to findings in the more developed countries, which have lower single-digit PVR rates.[11],[12]

Surgery remains the primary treatment for established PVR. The surgical goal is to remove the traction on the retinal surface, promote closure of retina breaks and reattachment of the retina. To aid visualization and, therefore, surgical removal of the epiretinal membranes present in PVR, vital dyes could be helpful.[13],[14] In some situations, a scleral buckle may be used in relaxing the traction, otherwise, a relaxing retinectomy may be performed.[15],[16] Despite the advances made in surgical treatment of PVR, the uncertainty of improvement in vision and better understanding of the disease process, there has been focus on research, development and trial of different pharmacological adjuncts targeting the different phases of the process.[17] This includes the development and trial of sustained release and biodegradable forms of antiinflammatory agents (steroids, e.g. intravitreal triamcinolone), antiproliferative agents/antineoplastic agents (5-fluorouracil, daunorubicin, retinoic acid, ribozymes, colchicine, vincristine, cisplatin, mitomycin, and dactomycin), antigrowth-factor agents (TGF-beta, kinase inhibitors, e.g. hypericin and herbimycin A), and antioxidant agents (N-acetylcysteine-NAC).[17]

The outcome of surgery in an exclusive group of PVR cases occurring in black Africans has not been reported previously. In our study, the reattachment rate for PVR grades C and D was 86% and 87%, respectively. This anatomical reattachment rate is better than reported by Ho et al. and Jalkh et al.[15],[16] and comparable to reports by de Bustros et al.[18] This suggests that the techniques employed were effective in reattaching the retina in the presence of advanced PVR. However, the visual outcome does not mimic the anatomical outcome. Postoperative vision is poor across all categories of surgical techniques. The average percentage visual improvement across the four categories of surgical technique in PVR C cases is 34.3% and the average percentage worsening of vision is 42.3%. In PVR D cases, it is was 33.3% and 28.3%, respectively. Therefore, it does appear that both PVR C and D have comparable rates of visual improvement (34.4% versus 33.3%), while PVR D has less percentage worsening compared to PVR C (28.3% versus 42.3%). However, this finding may be skewed because of the much higher numbers of PVR C eyes in this study. Other studies have reported a similarly poor visual outcome, which is characteristic of PVR.[15],[16],[17] Also, poorer anatomical outcomes which have been reported in more advanced PVR D eyes in the previous studies may be related to the techniques available two decades ago when these reports where published. Currently available more advanced vitreoretinal techniques and equipment give better anatomical outcomes.

None of the preoperative characteristics of the PVR RD considered including the presence of giant retinal tear, preoperative intraocular pressure, and number of quadrants of detached retina had a significant effect on the anatomical reattachment rate of the retina. Therefore, it does appear that the major factor determining the anatomical success is related to the experience and expertise of the surgeon(18), and also the technology available. Visual outcome, which was not directly related to the status of the retina, may be improved with a better understanding of the molecular effect of PVR on the ultrastructure and biochemical interaction at the macular in PVR eyes.[19] Since a significant number of eyes had 3 quadrants (20 eyes) or 4 quadrants (102 eyes) of detached retina, one can imagine that these categories of eyes already have a poor prognosis for visual return as all these eyes have a macular involving RD. Statistical analysis did not show any significant contribution of number of quadrants detached to anatomical outcome.

The presence of a giant retina tear (GRT) did not appear to have a negative effect on anatomical outcome on PVR D eyes and one wonders why since it is a causative factor for PVR. The anatomical failure rate in PVR C eyes with GRT was higher at 24% versus 12% for eyes without a GRT. However, for PVR D eyes, the failure rate for GRT was 0% versus 18% for eyes without GRT. However, this was not found to be statistically significant since the P value was 0.069.

Postoperative hypotony is a common complication of PVR surgery and contributes to a long-term poor outcome. Hypotony occurs because either the ciliary body shuts down due to repeated anatomic insults from the RD and ischemia and does not produce aqueous adequately, or the ciliary body is affected by extensive scar tissue that limits aqueous production. In this study, of the postoperative anatomically attached eyes, 24% of PVR C eyes and 37% of PVR D eyes had postoperative hypotony IOP < 6 mmHg. These rates are significantly higher in eyes with postoperatively detached retina at 33% and 67% for PVR C and D, respectively. This study confirms hypotony to be an important concern especially in postoperatively detached eyes. Therefore, the management of postoperative hypotony is an important concern that should be borne in mind when attending to PVR eyes. Preoperative IOP did not have any significant effect on anatomical outcome.


   Conclusion Top


In conclusion, this retrospective study though affected by a lack of a control group, and no standardization of surgical procedure, it is the first and largest series of an exclusive group of PVR eyes in a black African population. It agrees with other studies on PVR that poor visual outcome persists despite anatomical success following surgical intervention. It also showed that there was no statistically significant difference in anatomical outcome following different combination surgery for PVR. Therefore, the best-suited surgery will be one with which an experienced vitreoretinal surgeon is most comfortable with. Groundbreaking work is still required to improve visual outcome following PVR surgery, as several African patients will benefit from this.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
   References Top

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Ho PC, McMeel JW. Retinal detachment with proliferative vitreoretinopathy: Surgical results with scleral buckling, closed vitrectomy, and intravitreous air injection. Br J Ophthalmol 1985;69:584-7.  Back to cited text no. 15
    
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Jalkh AE, Avila MP, Schepens CL, Azzolini C, Duncan JE, Trempe CL. Surgical treatments of proliferative vitreoretinopathy. Arch Ophthalmol 1984;102:1135-9.  Back to cited text no. 16
    
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Sadaka A, Giuliari GP. Proliferative vitreoretinopathy: Current and emerging treatments. Clin Ophthalmol 2012;6:1325-33.  Back to cited text no. 17
    
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Deuchler V, Ackermann H, Singh P, Kohnen T, Wagner C, Koch F. Key factors to improve the outcome of retinal reattachment surgery in proliferative vitreoretinopathy and proliferative diabetic retinopathy. J Ophthalmol 2017, Article ID 2323897, 22 pages. https://doi.org/10.1155/2017/2323897.  Back to cited text no. 19
    


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