Nisa Silva, Natalia Ferreira, Bernardete Pessoa, Nuno Correia, Melo Beirao, Angelina Meireles, Portugal

Introduction:
In 2010, Michalewska et al. published the first results of internal limiting membrane (ILM) inverted flap technique in the surgical treatment of macular holes. Several studies have reported closure rates between 89% and 100% with this technique.

Objectives:
To evaluate the functional and anatomical results of inverted flap surgical technique in the treatment of macular holes. Methods: Retrospective unicentric cohort study of eyes submitted to ILM inverted flap for macular hole treatment between June 2008 and June 2018. All eyes were submitted to pars plana vitrectomy (3 ports, 23 gauge) using brilliant blue/double dyne® or indocyanine green dye for ILM peeling with inverted flap and gas tamponade. Cases of pseudohole or lamellar hole, secondary to vitrectomy and retinal detachment presence were excluded. The primary functional outcome was defined as ≥0.3 logMAR units (15 letters) improvement of best corrected visual acuity (BCVA). Measurement of BCVA on the Snellen scale (converted to logMAR) was obtained at diagnosis, and at post-surgical outpatient clinic evaluation up to 3 months, between 3 and 6 months, between 6 and 12 months and after 12 months. Predictive factors of a final logMAR BCVA >0.3 were determined. The primary anatomical result was defined as the closure of the macular hole confirmed by Spectral Domain Optical Coherence Tomography (OCT- SD). The closure was classified as type V, U or flat-open. Morphological analysis of the ellipsoid zone in the OCT-SD at the last follow-up was considered the secondary anatomical outcome. Statistical analysis was performed using SPSS ® v.24.0.

Results:
One hundred and twenty eyes of 113 patients, 62.5% (n = 75) female, with a mean age of 69±8 years, were evaluated. The median follow-up period was 16 [Interquartile range (IQR) 5-34] months. Seventy percent (n=82) of the eyes were phakic. The macular hole was unilateral in 82.4% (n=91) and idiopathic in 90.8% (n=109). High myopia was the cause in 9.2% (n=11). Of the eyes submitted to surgery, 22.1% were grade 2, 25.3% grade 3 and 52.6% grade 4. The median minimum diameter was 480μm (IQR 296-605) and the median macular hole index (height/diameter of the base) was 0.47 (IQR 0.36-0.72). An epiretinal membrane was present in 31.9% (n=37). The median duration of the macular hole was 12 (IQR 4-27) months. SF6® was the gas used in 90.0% (n=108). The procedure was combined with cataract surgery in 22.4% (n=19) of the phakic eyes. Secondary cataract surgery was required in all phakic eyes post-inverted flap (except in 1 case) after a median period of 12 (IQR 7-24) months. There w as a decrease in the logMAR BCVA from a median value of 1.0 (IQR 0.70-1.40) at diagnosis to 0.7 (IQR 0.48-1.00, p<0.001) up to 3 months, 0.7 (IQR 0.40-0.92, p<0.001) between 3 and 6 months, 0.52 (IQR 0.30-0.92, p<0.001) between 6 and 12 months and 0.52 (IQR 0.26-0.92, p<0.001) after 12 months. Seventy five percent (n=86) improved ≥0.3 logMAR units in BCVA. The macular hole closure rate was 92.5% (n=111). Flap-open closure was reported in 14 cases (11.7%). Of the nine eyes that didn’t close post-inverted flap, five closed after being submitted to the second surgical intervention (n=3 radiating technique; n=1 flap repositioning; n=1 completed ILM peeling). Changes in the subfoveal ellipsoid zone in the last OCT-SD were found in 85.1% (n=74), including atrophy in 46% (n=40), disruption in 31% (n=27) and narrowing in 8% (n=7). Eyes with these changes had a significant higher median logMAR BCVA at the end of follow-up (0.60 vs 0.15; p<0.001). In the logistic regression, grade [Odds ratio (OR) 0.07; p=0.01] and minimum diameter (OR 1.01; p=0.006) were predictive factors of a worse functional result.

Conclusion:
The flap-inverted technique was shown to be effective with a closure rate greater than 90%. Persistent changes of the ellipsoid zone in the OCT-SD are frequent, in probable relation to the limited reversibility of photoreceptor damage. This technique enabled a visual acuity improvement of at least fifty letters in 75%. Macular hole grade and minimum diameter were predictive factors of the functional outcome.

Contact Details:
Nisa Silva
Centro Hospitalar e Universitario do Porto
Porto
Portugal
Cell Phone : 00351918367661
Work Phone : 00351918367661
Email : nisapinhosilva@gmail.com