Comparison of Persistent Submacular Fluid in Vitrectomy and Scleral Buckle Surgery for Macula-Involving Retinal Detachment




Purpose


To compare the frequency of persistent submacular fluid (SMF) and sequential visual outcomes after pars plana vitrectomy (PPV) and scleral buckling (SB) in recent-onset macula-involving rhegmatogenous retinal detachment (RD), and thus to determine the role of persistent SMF on visual outcome with different surgical methods.


Design


Observational case series.


Methods


Sixty-one patients (61 eyes) who underwent successful PPV (16 patients) or SB (45 patients) underwent thorough ophthalmologic examinations including optical coherence tomography at 1 month after surgery, as well as every 3 months until SMF disappeared. The SB group was divided into 2 groups according to the presence (SB-SMF+) or absence (SB-SMF−) of persistent SMF at 1 month after surgery. Preoperative and postoperative best-corrected visual acuities were compared among the different surgical groups and also were analyzed depending on the RD duration (acute, symptom duration ≤ 7 days; subacute, symptom duration > 7 and ≤ 30 days).


Results


Persistent SMF at 1 month after surgery was more frequent in the SB group (55.6%) than it was in the PPV group (6.25%; P = .006). The SB-SMF+ group showed worse postoperative best-corrected visual acuity than the PPV or SB-SMF− groups at 6 to 12 months after surgery, whereas there were no significant differences in the final visual acuity among the groups. This difference in visual recovery was not observed in patients with subacute RD.


Conclusions


The similar visual recovery patterns seen in the PPV and SB-SMF− groups suggest that persistent SMF is a more important prognostic factor than surgical method is in the setting of acute onset and successful RD surgery.


With the advent of optical coherence tomography (OCT), subclinical submacular fluid (SMF) often has been shown to persist for months after successful retinal detachment (RD) surgery, without being recognized by ophthalmoscopy. Although the influence of persistent SMF on visual outcomes is controversial, our previous study suggested that transient, postoperative, persistent SMF after successful scleral buckling (SB) surgery for acute RD did not affect the final visual outcome. However, it may delay visual recovery. There have been several studies comparing visual and anatomic outcomes after pars plana vitrectomy (PPV) and SB in primary rhegmatogenous RD. However, most of the studies did not considered the influence of persistent SMF on visual recovery after RD surgery.


Wolfensberger reported the time course of foveal reattachment after PPV and SB; however, the information on visual outcome was not represented. Benson and associates investigated the incidence and duration of persistent SMF after PPV and SB in 2 separate studies and found that SMF was absorbed more rapidly in PPV than it was in SB and that persistent SMF may cause delayed visual recovery. If SMF is absorbed more rapidly in PPV than SB, and persistent SMF delays visual recovery and is a more important factor affecting visual outcome than the surgical method itself, then the visual recovery pattern of those who underwent PPV may be similar to that of those who underwent SB with rapid SMF absorption rate. However, no study has made a direct comparison between SB and PPV with a focus on SMF-related delays in visual recovery. The purpose of this study was to compare the frequency of persistent SMF and related visual outcomes after PPV and SB in recent-onset macula-involving (both macula-off and macula-splitting) RD, and thus to determine the role of persistent SMF on visual outcome with different surgical methods.


Methods


We reviewed the medical records of patients who underwent PPV and gas (C 3 F 8 14%) tamponade or SB surgery for primary spontaneous macula-involving (both macula-off and macula-splitting) rhegmatogenous RD at Seoul National University Bundang Hospital between January 1, 2004, and December 31, 2007. During that period, 81 patients underwent PPV and gas tamponade and 126 patients underwent SB for treatment of rhegmatogenous RD. Sixty-one eyes in 61 consecutive patients who underwent PPV and gas tamponade (PPV group, 16 patients) or SB surgery (SB group, 45 patients) and who met the inclusion criteria finally were enrolled in this study. Inclusion criteria were: (1) symptom onset less than 30 days and an early postoperative course of successful retinal reattachment; (2) follow-up examination of at least 6 months after surgery; (3) patients with persistent SMF followed up for at least 6 months after complete SMF disappearance; and (4) patients who underwent cataract surgery during the postoperative follow-up period, at least 3 months of follow-up after the cataract surgery. Exclusion criteria were: (1) silicone oil injection; (2) history of both vitrectomy and SB surgery; (3) immediate reoperation attributable to failed surgery; (4) trauma history; (5) preexisting macular pathologic features, such as age-related macular degeneration, macular hole, or macular edema; (6) conditions likely to influence retinal flattening after RD surgery, such as proliferative vitreoretinopathy, epiretinal membrane, vitreomacular traction syndrome, and combined tractional detachment attributable to diabetes; (7) a history of intraocular surgery other than an uncomplicated cataract operation; (8) visually significant cataract that was not treated with cataract surgery during the follow-up; and (9) inability to undergo OCT.


All surgeries were performed by an experienced retinal surgeon (P.K.H.). Each procedure, PPV or SB, was selected based on the surgeon’s decision. Young patients with inferior tears and RD were likely to undergo SB surgery, whereas older patients with cataracts or pseudophakia and suspicious or hidden tears were more likely to undergo PPV. We did not perform external subretinal fluid drainage during SB surgery. Twenty-nine of 45 patients treated with SB unintentionally were drawn from the patients in our previous study, and we did not exclude them so as to increase the statistical power.


All patients underwent thorough ophthalmologic examinations, including best-corrected visual acuity (BCVA; Snellen visual acuity chart), slit-lamp examination, binocular indirect ophthalmoscopy, and OCT (Stratus OCT; Carl Zeiss Ophthalmic System, Dublin, California, USA) at 1 month after surgery and every 3 months thereafter until SMF disappeared. OCT was performed by 1 experienced technician until SMF disappeared completely. Only OCT images with signal strengths of 5 or more were used.


If a visually significant cataract developed during the follow-up, we performed cataract surgery and the visual acuity at that point was adopted from the visual acuity at 1 month after cataract surgery. For example, if visually significant cataract developed at 6 months after surgery, we performed cataract surgery immediately and adopted the visual acuity at the 7-month (1 month after cataract surgery) follow-up. Final visual acuity was defined as visual acuity obtained at least 6 months after SMF disappearance and at least 3 months after cataract surgery in patients who underwent cataract extraction during the follow-up.


To compare the frequency and duration of persistent SMF after PPV and SB surgery, the survival curves of persistent SMF after PPV and SB surgery were compared using Kaplan-Meier survival analysis. To evaluate the effect of surgical procedures on postoperative BCVA, we compared preoperative and postoperative BCVA between the PPV and SB groups. We also evaluated the effect of persistent SMF on postoperative BCVA by dividing the SB group into 2 subgroups: an SB-SMF− group with no persistent SMF at 1 month after surgery and an SB-SMF+ group with persistent SMF at 1 month after surgery. This classification was fixed throughout the study regardless of SMF status throughout the follow-up, and also there was no recurrence of SMF after it had disappeared. We did not divide the PPV group according to the persistence of SMF because all of the PPV group patients except one had no SMF at 1 month after surgery. The preoperative and postoperative BCVAs were compared among the PPV, SB-SMF−, and SB-SMF+ groups using the Mann–Whitney U test. Finally, we divided patients according to disease chronicity: the acute group had symptom duration of 7 days or fewer, and the subacute group had symptom duration of more than 7 day and 30 days or fewer. We compared preoperative and postoperative BCVAs among the PPV, SB-SMF−, and SB-SMF+ subgroups in each acute and subacute disease group using the Mann–Whitney U test. Statistical analyses were performed using SPSS software version 12.0 (SPSS, Inc, Chicago, Illinois, USA), and P values < .05 were considered statistically significant. A P value of .05 to < .1 were considered to indicate borderline significance.




Results


Patients who underwent PPV were significantly older than those who underwent SB (average, 56.4 ± 9.1 years vs 39.2 ± 17.0 years; P < .001). There were no significant differences in symptom duration between the PPV and SB groups. Superior RD patients had a tendency to undergo PPV, and inferior RD patients had a tendency to undergo SB. Cataract surgery was performed in 1 patient at the time of vitrectomy and in 11 patients during the postoperative period (8.4 ± 2.9 months after PPV). There were significant differences in the rate of postoperative cataract development between the PPV and SB groups. Cataract developed in 11 of 13 phakic eyes in the PPV group, whereas it developed in 0 of 39 phakic eyes in the SB group ( P < .001, Fisher exact test). Patient demographics and clinical characteristics are summarized in Table 1 .



TABLE 1

Demographic and Clinical Characteristics of Patients Who Underwent Pars Plana Vitrectomy or Scleral Buckling for Primary Macula-Involving Rhegmatogenous Retinal Detachment
















































































































































PPV (n = 16) SB (n = 45) P Value a
Age (yrs) 56.4 ± 9.1 39.2 ± 17.0 < .001
Male gender (%) 62.5 55.7 .572
Preoperative BCVA (logMAR) 1.30 ± 0.78 1.19 ± 0.73 .526
Preoperative IOP 11.1 ± 3.8 11.9 ± 3.2 .322
Follow-up (mos) 20.1 ± 10.9 20.8 ± 11.3 .889
Duration of symptoms (days) 10.6 ± 11.0 6.8 ± 6.9 .556
Preoperative macula status 1.000
Macula off (%) 68.8 68.9
Macula splitting (%) 31.2 31.1
Phakic lens status (%) 87.5 86.7 1.000
High myopia b (%) 12.5 35.6 .114
Clock hours of RD (%) .646
1 to 3 0 6.7
4 to 6 56.3 60.0
7 to 9 25 22.2
10 to 12 18.7 11.1
Location of RD (%) .017
Superior 68.8 26.7
Inferior 6.3 35.6
Superior and inferior 12.5 26.7
Total RD 12.5 11.1
Break numbers 1.7 ± 0.9 1.8 ± 1.3 .835
Type of break (%) .052
Tear 87.5 57.8
Hole 0 26.7
Both 12.5 15.6
Significant cataract formation after surgery 11/13 (84.6%) 0/39 (0.0%) < .001

BCVA = best-corrected visual acuity; IOP = intraocular pressure; logMAR = logarithm of the minimal angle of resolution; PPV = pars plana vitrectomy; RD = retinal detachment; SB = scleral buckling.

All data are represented by average ± standard deviation, except those representing percent (%).

a P value by Mann–Whitney U test, chi-square test, and Fisher exact test.


b Definition of high myopia: affected eye spherical equivalent, −6 diopters or less: or axial length, 28 mm or more.



Figure 1 represents the survival graphs of persistent SMF in both groups. In the PPV group, SMF disappeared before 1 month after surgery in 15 of 16 patients. Persistent post-PPV SMF in the remaining patient disappeared before 12 months after surgery (average, 1.7 ± 2.8 months). In the SB group, SMF disappeared more slowly. Only 21 of 45 patients showed disappearance of SMF before 1 month, and the longest duration of SMF persistence was 42 months (average, 5.5 ± 7.3 months; P = .006, PPV vs SB, Kaplan-Meier analysis).




FIGURE 1


Kaplan-Meier survival curve for persistent submacular fluid (SMF) after pars planar vitrectomy (PPV) and scleral buckling (SB) for macula-involving rhegmatogenous retinal detachment. The incidence and duration of persistent SMF was significantly different between the 2 surgical groups ( P = .006, log-rank test).


There were no significant preoperative or postoperative BCVA differences between the PPV and SB groups during the follow-up ( Table 2 ; Figure 2 , Left). However, when we divided the SB group into 2 subgroups according to the persistence of SMF, there were significant BCVA differences between the PPV and SB-SMF+ groups at 9 and 12 months after surgery, and there were significant BCVA differences between the SB-SMF− and SB-SMF+ groups at 6, 9, and 12 months after surgery. Nevertheless, there were no significant differences in the final BCVA among the 3 groups ( Table 2 ; Figure 2 , Right).



TABLE 2

Comparison of Preoperative and Postoperative Best-Corrected Visual Acuity (Logarithm of the Minimal Angle of Resolution Scale) between the Pars Plana Vitrectomy and Scleral Buckling Groups for Macula-Involving Rhegmatogenous Retinal Detachment






























































































Preoperative 1 Mo 3 Mos 6 Mos 9 Mos 12 Mos Final
PPV (n = 16) 1.30 ± 0.78 0.52 ± 0.33 0.39 ± 0.33 0.24 ± 0.17 0.17 ± 0.25 0.13 ± 0.23 0.15 ± 0.20
SB (n = 45) 1.19 ± 0.73 0.51 ± 0.34 0.34 ± 0.30 0.26 ± 0.25 0.25 ± 0.23 0.23 ± 0.25 0.19 ± 0.25
SB-SMF− (n = 19) 1.17 ± 0.71 0.46 ± 0.30 0.27 ± 0.28 0.18 ± 0.22 0.17 ± 0.20 0.13 ± 0.19 0.13 ± 0.21
SB-SMF+ (n = 26) 1.21 ± 0.75 0.54 ± 0.37 0.38 ± 0.32 0.31 ± 0.25 0.31 ± 0.23 0.28 ± 0.27 0.23 ± 0.27
P values a
PPV vs SB .526 .798 .294 .661 .217 .196 .740
PPV vs SB-SMF− .612 .683 .133 .117 .837 .964 .612
PPV vs SB-SMF+ .558 .938 .638 .582 .039 .049 .351
SB-SMF− vs. SB-SMF+ .908 .571 .183 .029 .020 .047 .149

mo = month; PPV = pars plana vitrectomy; SB = scleral buckling; SB-SMF+ = patients with persistent submacular fluid 1 month after SB; SB-SMF− = patients without persistent submacular fluid 1 month after SB.

All data are represented by average ± standard deviation, except those representing percent (%).

a Mann–Whitney U test.




FIGURE 2


Bar graphs comparing preoperative (preop) and postoperative best-corrected visual acuity (BCVA; logarithm of the minimal angle of resolution [logMAR] scale) of patients with macula-involving rhegmatogenous retinal detachment in different surgery groups. (Left) PPV versus scleral buckling (SB) overall. (Right) PPV versus SB divided into 2 subgroups according to the presence of submacular fluid (SMF) after 1 month after surgery: those with no SMF 1 month after surgery (SB-SMF−), and those with persistent SMF 1 month after surgery (SB-SMF+). P values were calculated using the Mann–Whitney U test. PPV = pars plana vitrectomy.


When patients were categorized according to disease chronicity, the PPV group showed marginally better BCVA at 9 months ( P = .095) and 12 months ( P = .065) after surgery compared with the SB-SMF+ group, and the SB-SMF− group showed marginally better BCVA at 6 months ( P = .091) and 9 months ( P = .053) after surgery compared with the SB-SMF+ group in acute RD patients ( Table 3 ; Figure 3 , Left). There were no significant differences in final BCVA among the 3 subgroups in acute RD patients. However, among subacute-onset RD patients, no significant differences in postoperative BCVA were found between the PPV and SB-SMF+ groups ( Table 3 ; Figure 3 , Right). In the SB group, 50% of acute RD patients showed persistent SMF, but 100% of subacute RD patients showed persistent SMF at 1 month after surgery ( P < .001, Fisher exact test).


Jan 17, 2017 | Posted by in OPHTHALMOLOGY | Comments Off on Comparison of Persistent Submacular Fluid in Vitrectomy and Scleral Buckle Surgery for Macula-Involving Retinal Detachment
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