Vitrectomy with internal limiting membrane peeling versus its flap insertion for macular hole in high myopia: A Meta-analysis

Methodological quality of the review: Medium confidence

Author: Ya-Jun Wu, Jie Rao1, Kang-Rui Wu, Na Wu, Yi Cheng, Xiao-Xuan Xu, Li Yan, Yi Shao, Yu Tian, Xiao-Rong Wu

Region: Japan, Taiwan, China

Sector: Myopia

Subsector: Myopia treatment

Equity focus: No

Study population: Adults

Type of programme: Clinical based

Review type: Other review

Quantitative synthesis method: Meta-analysis

Qualitative synthesis method: Not applicable

Background: Macular hole (MH) is a full-thickness neuroretinal defect that occurs in the retina. According to the International Vitreomacular Traction Study (IVTS), vitreous liquefaction will lead to posterior vitreous detachment and further progress to vitreous macular adhesion, which can eventually develop into pathological vitreous macular traction and MH; the latter usually will result in damage to central vision. High myopia MH [axial length >26 mm or diopter (D) of at least 6] is one of the most common types of MH, which can easily lead to retinal detachment (RD). Vitrectomy with traditional internal limiting membrane (ILM) peeling technique is regarded as the gold standard treatment for MH; it works by completely relieving of the traction of the macula and increasing the flexibility of the retina. However, the ILM peeling technique may fail to close the hole, or may cause secondary MH or foveoschisis. There have not been large numbers of investigations to distinguish the outcomes, such as the MH closure rate between conventional pars plana vitrectomy (PPV) combined with ILM peeling and PPV combined with ILM insertion into the MH.

Objectives: The objective of this review was to compare the anatomic and functional outcomes between vitrectomy with internal limiting membrane (ILM) peeling and internal ILM flap insertion technique for high myopia macular hole (MH).

Main findings: Following application of the inclusion and exclusion criteria, five articles, which were all retrospective studies, were included in this analysis. A total of 151 eyes were included; 62 eyes underwent ILM flap insertion, while 89 eyes underwent conventional ILM peeling. The rate of closure of MH in the ILM insertion group was significantly better than that of the ILM peeling group in all studies (OR=21.32, 95% CI=7.25-62.67, P<0.001, with no heterogeneity (I²=0, P=0.73). In order to determine which method could more clearly improve BCVA, we constructed two subgroups, preoperative BCVA and postoperative BCVA (six months after the initial surgery); we used these groups to compare the effect between the conventional surgery and the insertion technique. The preoperative BCVA was recorded in all five studies; there was no statistically significant difference between the techniques. The postoperative BCVA also showed no significant difference between the ILM insertion and ILM peeling groups.

Methodology: Inclusion criteria consisted of studies: 1) comparing outcomes of patients treated with vitrectomy with conventional ILM peeling vs ILM flap insertion for MH in high myopia; 2) retrospective study reported the surgery treatment for MH in high myopia; 3) reporting the detailed and sufficient outcomes, such as the rate of MH closure and BCVA, and following-up’s data. A literature search of citations was performed on PubMed, the Cochrane Library, Embase and CKNI (the largest database of science in China). We were searching the studies by using following terms: macular hole OR retinal break AND high myopia AND internal limiting membrane peeling OR ILM flap insertion. The final search was carried out on June 2018. There were no restrictions in included articles’ language and publishing year. Studies with available dates were included. Review, case report, meeting abstract and articles’ lacks comparing were excluded. By reading titles and abstracts, two independent investigators (Yan L and Wu N) roughly selected useful articles. They also read the full texts to choose those potential literatures in the meta-analysis, which followed above criteria. Two reviewers extracted information from included studies independently and rechecked carefully. The data from selected studies included the first author, publication year, country, trial type, age, gender, axial length number of subjects, surgical procedures, gas used, closure rate preoperative and postoperative BCVA. Cochrane Collaboration’s Review Manager Software was used for data analysis. We analysed dichotomous variables: the closure rate of MH by using estimation of odds ratios (OR) with a 95% confidence interval (CI). Statistical heterogeneity among studies was evaluated with the Q test and I² statistic; publication bias was evaluated by using a funnel plot.

Applicability/external validity: The authors acknowledge some deficiencies in their review which need to be considered when interpreting the results. They had limited data available to analyse retinal reattachment between the two groups, and there was no statistical difference between the two groups.

Geographic focus: Not discussed, but this review included studies from three Asian countries. Results may be specific just for this region.

Summary of quality assessment:

Medium confidence was attributed in the conclusions about the effects of this study. Although authors used appropriate methods to conduct the review, authors/experts were not contacted for further potentially relevant studies to be included in the review. In addition, the four studies which were included in the meta-analysis contained limited data for a robust analysis of retinal reattachment between groups.