Postoperative retinal microstructure and functional outcome after inverted-flap technique associated with silicone oil tamponade in macular hole surgery

Abstract

Purpose: Our retrospective study on 27 patients with a large mean macular hole diameter (MH-D) of 480.08±78.62 μm evaluates the usefulness of combining the current internal limiting membrane (ILM) inverted-flap surgical technique with silicone oil tamponade, which has been associated with the classical technique of ILM peeling.

Results: Functional results: mean visual acuity (VA) improved to 0.89±0.11 logMar (logarithm of the minimum angle of resolution, at one month), 0.67±0.03 logMar (at three months), 0.52±0.04 logMar (at six months), 0.42±0.15 logMar (at one year) postoperative (final VA), with statistical linkage between preoperative VA and final VA (two-sample t-test, p=0.007), mean MH-D and final VA (regression analysis, p=0.003). We compared the results by MH size (Group A ≤400 μm - eight eyes and Group B >400 μm - 19 eyes), finding statistical variance (Bonett & Levene methods). Group A presented a final VA of 0.21±0.12 logMar, while Group B had 0.51±0.17 logMar. Successful closure was noted in 25 (92.59%) cases, with Group A having complete closure and external limiting membrane (ELM) restoration with ellipsoid zone (EZ) regeneration in six cases. Group B had successful closure in 17 (89.47%) cases with ELM restoration in 16 cases and EZ regeneration in seven (38.88%) cases, with reintervention in two cases. Restoration of the ELM was correlated [Pearson's correlation coefficient (PCC) of 0.999, p=0.022] with successful closure, with overall restoration obtained in 24 (88.88%) cases and EZ regeneration in 13 (48.14%) cases.

Conclusions: ILM inverted-flap technique with silicone oil tamponade had favorable functional and anatomical outcomes. ELM restoration was associated with successful MH closure.

Figure 1

An example of a high-resolution OCT combining swept-source and spectral domain acquisition (Heidelberg Spectralis^®, Heidelberg Engineering GmbH, Heidelberg, Germany) presenting a normal eye with cilioretinal arterial anatomical variation, with annotation of the anatomical elements. Author’s OCT examination, conducted in our practice on one of the author’s papers and subsequently annotated by the same author with the anatomical elements. Written permission was obtained for usage of the final annotated image in the publishing of this paper. OCT: Optical coherence tomography

Figure 2

Testing for normal distribution of the patient demographics and surgical data using the Anderson–Darling normality test finding no significant departure from normality (p>0.05), both on all patient data as well as data divided into Group A and Group B with p-value of 0.246 for Group A and 0.251 for Group B (both >0.05). ELM: External limiting membrane; EZ: Ellipsoid zone; logMAR: Logarithm of the minimum angle of resolution; MH: Macular hole; MH-D: MH diameter; pre-op: Preoperative; post-op: Postoperative; VA: Visual acuity

Figure 3

Comparison of pre-op VA and VA at one-year post-op, pre-op mean MH-D and pre-op VA, VA at one-year post-op and pre-op mean MH-D. The regression analysis fitted line plot models the relationship between one predictor and a continuous response and in our study highlights a direct, linear relation between pre-op VA, mean MH-D and final post-op VA at one year. A fitted line plot comparing pre-op with final post-op VA returned a linear regression a R-Sq value of 100% and a p<0.05 (noted as * by Minitab), with a two-sample t-test between pre-op and post-op VA returning a p-value of 0.007 <0.05. A similar relation between the mean MH-D and final one-year post-op VA was found (regression analysis R-Sq value of 100%, p=0.003 <0.05). Furthermore, pre-op VA and mean MH-D were nearly interchangeable values to each other (linear regression R-Sq value of 100%, R-Sq predicted 99.96%, p=0.003) with both strongly linked to final post-op VA at one year. CI: Confidence interval; logMAR: Logarithm of the minimum angle of resolution; MH: Macular hole; MH-D: MH diameter; pre-op: Preoperative; post-op: Postoperative; VA: Visual acuity

Figure 4

Testing for variance between surgical data of Group A (MH-D ≤400 μm) and Group B (MH-D >400 μm) using Bonett & Levene methods: (A) A statistically significant variance was found between Group A and Group B when comparing surgical data (successful post-op closure of the MH, ELM restoration, EZ restoration, cases requiring reintervention) using Bonett & Levene tests (Bonett p=0.205 >0.05, Levene p=0.117 >0.05); (B) Statistical variance when comparing post-op VA at one year (Bonett p=0.873) between Group A and Group B. CI: Confidence interval; ELM: External limiting membrane; EZ: Ellipsoid zone; MH: Macular hole; MH-D: MH diameter; post-op: Postoperative; VA: Visual acuity

Figure 5

Pearson’s correlation with pairwise table measuring linear correlation between two sets of data. A PCC of 1 denotes the highest correlation with a linear relationship, while a value closer to 0 denotes no linear dependency. We confirmed strong correlation between the following variables: VA pre-op and pre-op mean MH-D (PCC of 1, p=0.003), VA at one-year post-op and pre-op mean MH-D (PPC of 1, p=0.003), ELM restoration and successful post-op MH closure (PPC of 0.999, p=0.022) and confirmed an exactly linear relation between VA at one-year post-op and initial VA pre-op (PPC of 1, p<0.05, noted as * by Minitab). Weaker correlations with high p-values (between 0.144 and 0.189) could be noted between VA pre-op or VA at one-year post-op and mean patient age (PCC of 0.973 and 0.974, p=0.144), pre-op mean MH-D and mean patient age (PCC of 0.973, p=0.147), VA at one-year post-op and cases requiring reintervention (PCC of 0.956, p=0.189), however were found to have no statistical significance (p>0.05). ELM: External limiting membrane; logMAR: Logarithm of the minimum angle of resolution; MH: Macular hole; MH-D: MH diameter; PCC: Pearson’s correlation coefficient; pre-op: Preoperative; post-op: Postoperative; VA: Visual acuity