Novel surgical approaches for treating myopic traction maculopathy: a meta-analysis

Myopic traction maculopathy (MTM) is characterized by significant retinoschisis-like thickening of the outer retina accompanied by posterior staphyloma (PS) in highly myopic eyes [1]. MTM is considered a major complication of pathologic myopia (PM) and is projected to become a leading cause of visual impairment worldwide in the coming decades [2, 3]. The prevalence of visual impairment and blindness associated with PM ranges from 12 to 27% in Asian populations and 7% in Western populations [3‐6]. MTM has been identified and categorized via the extensive application of OCT and vitrectomy techniques [7]. Additionally, studies have reported the occurrence of epiretinal membranes (ERMs), macular retinoschisis (RS), stretched retinal vessels, different degrees of posterior staphyloma (PS), outer lamellar macular holes (MHs), full-thickness MHs (FTMHs), abnormally rigid inner limiting membrane (ILM), foveal retinal detachment (FRD), and MH retinal detachment (MHRD) [3, 8‐10]. MTM progression is driven by increasing traction exerted on these structures [11].

The ab externo surgical approach for MTM was introduced long before its definition in 1930. In terms of treatment, surgery is recommended for patients with reduced visual acuity, detached fovea, FTMH, or champagne-flute-shaped retinoschisis and MHRD [12, 13]. Surgical treatment options include pars plana vitrectomy (PPV) with or without ILM stripping and macular buckling (MB) [14, 15]. In 1957, Schepens et al. proposed the MB technique, which has since been considered the best surgical approach for the treatment of myopic MHRD [16]. In 2012, Shimada et al. presented an innovative approach to myopic FRD surgery known as fovea-sparing internal limiting membrane peeling (FSIP). In contrast to the standard ILM peeling (ILMP) technique, the FSIP technique retains a portion of the ILM attached to the fovea, demonstrating greater efficacy in preventing MH development [17, 18]. Recently, several novel surgical methods, including autologous neurosensory retinal-free patch transplantation [19], lens capsular flap transplantation [20], ILM repositioning with autologous blood clotting (ABC) [21] and inverted ILM insertion [22], have been proposed for MTM. According to Michalewska et al., the postoperative closure rate using the inverted ILM flap technique was better (98%) for large idiopathic MHs than for small idiopathic MHs [23]. Following the same procedure as that used for myopic MH treatment, Kuriyama et al. [22] reported a closure rate of 80%. Recently, Chen et al. [24] reported a closure rate of 100% using inverted ILM insertion for MHRD in highly myopic patients.

Numerous surgical techniques are available for the treatment of MTM, but there is no standard treatment approach. Recent advancements in various surgical techniques have introduced new viable options for MTM treatment [25]. However, it is necessary to thoroughly examine these studies to validate their effectiveness and ensure their methodological rigor in assessing the efficacy of surgical treatments for MTM. Careful evaluation of their methodology, study design, and outcome assessments is required to derive compelling and coherent conclusions regarding their impact on patients. Therefore, we conducted a comprehensive review and meta-analysis of clinical studies involving MTM patients who underwent surgical treatment. This study aimed to compare the outcomes of different surgical treatments for MTM. Numerous studies have reported that the application of the FSIP technique for treating MTM leads to improved visual and anatomical outcomes [26, 27]. This meta-analysis aimed to increase the sample size, obtain more reliable findings to validate previous studies, and provide updates on the preferred surgical approach based on recently published studies.

After the database searches, 273 articles were retrieved using various keywords. Initially, reviews, case reports, correspondences, abstracts, and irrelevant documents were excluded. Subsequently, 34 additional studies were excluded after screening the titles and abstracts. Among the remaining studies, five were excluded because of insufficient data and irrelevant interventions. Upon assessment of the full text, 10 English studies were deemed eligible for meta-analysis (Fig. 1). Of these, nine studies compared standard ILMP to FSIP, while one study compared inverted ILM insertion versus the ILM flap with the ABC technique; these studies were not included in the meta-analysis. All nine selected studies were comparative nonrandomized and retrospective studies. No other novel comparative interventions were identified in this study.

We conducted a meta-analysis of nine studies to evaluate the safety and efficacy of FSIP versus standard ILMP for MTM. A total of 350 eyes were included; 141 eyes were subjected to FSIP treatment, while 209 eyes were treated with standard ILMP. Both groups exhibited similar anatomical outcomes; however, these results support the use of the FSIP technique, which yields better postoperative visual outcomes based on the mean change in logMAR BCVA from baseline. There was a significant difference in the incidence of postoperative MHs between the two groups. Specifically, the postoperative MH rate was lower in the FSIP group (4.25%) than that in the standard ILMP group (8.6%).

According to a meta-analysis by Wu et al. [37], the FSIP group achieved a better postoperative BCVA; however, a comparison of postoperative BCVA was insufficient because differences may have existed at baseline, affecting the postoperative findings. Therefore, we determined the mean change in logMAR BCVA from baseline and observed that the FSIP group had a greater mean improvement than the standard ILMP group. The greater percentage of postoperative MHs in the standard ILMP group might be the reason for the improvement in BCVA in the FSIP group because the visual prognosis is poor in patients with high myopia and MHs [38]. This statement is supported by (Ho et al., 2014) [26], who observed a greater rate of inner/outer segment (IS/OS) line restoration in the FSIP group (9/12) than in the standard ILMP group (1/7), which might have contributed to the better final BCVA. According to Rubinstein et al. [39], FTMH occurs after surgery because of ILM-induced trauma. Moreover, they proposed that bleeding occurs in a small area during peeling, leading to postoperative FTMH. In addition, Hussain and Mitra [40] reported that ILM detachment may cause mechanical damage to the inner retina, which may lead to apoptosis of glial cells, resulting in degeneration of neurons and contributing to the formation of postoperative FTMHs. Based on our findings and those of previous research, the unique characteristics of highly myopic eyes, such as increased axial length and structural changes, may have contributed to the greater incidence of FTMH in the ILMP group. These factors may influence the healing process differently in symptomatic eyes compared to healthy eyes.

Importantly, different surgeons have different remnant foveolar ILM diameters in the FSIP. In a study by Wang et al. (2012) [13], the foveal ILM diameter was preserved along the vertical extent of the optic disc. Subsequently, (Elwan et al., 2019) [32] and (Iwasaki et al., 2020) [33] followed the same technique as Shimada et al.; however, the exact diameter was not specified by Elwan et al., while Iwasaki’s group left a 0.5 to 1.0 disc diameter. The size of the preserved ILM was one papillary diameter (PD) in the study by Wang et al. (2019) [34], while in the study by Xin et al. (2022) [31], an ILM of approximately 1 to 1.5 papillary diameter centered on the fovea centralis was retained, whereas in the standard ILMP group, it was completely removed from 16 eyes. The VA and foveolar structure did not deteriorate over the course of follow-up, which was expected given the assumption that any persisting ILM would function as a preretinal membrane. However, (Ho et al., 2014) [26] and (Tian et al., 2018) [27] chose to reserve ILMs with diameters of 300–500 μm and 500 μm, respectively, because they found that these sizes were suitable for complete foveolar covering and adequate traction release. To the best of our knowledge, the preservation of a smaller section produces better results because the probability of recurrence is lower; however, additional expert surgeries are needed. However, the aforementioned research findings were satisfactory, and it is unlikely that size has an impact on the outcome. Currently, there is no consensus on the extent to which the foveolar ILM should be preserved; thus, further comparative studies and long-term follow-up are needed.

The results of this meta-analysis should be evaluated with caution due to several limitations. One major limitation is that we did not find any comparative studies on novel surgical approaches. After an in-depth search, we found only one comparative study that was not included in the meta-analysis because no other comparative studies were conducted for the same intervention. Future studies should be conducted on these interventions to assess their safety and efficacy. Among the nine included studies, eight were retrospective, and the only prospective study was not randomized. Prospective RCTs with larger sample sizes are required to obtain more conclusive results. Nonetheless, nonrandomized clinical trials contain many uncontrollable factors and lack sufficient data to draw precise conclusions. Moreover, the number of eyes, tamponades, dyes used to stain the ILM, and follow-up times were different in all studies; however, these aspects were not highlighted in this meta-analysis. The follow-up periods of the studies were different and covered an extensive range, from 6 months (Elwan et al., 2019) [32] to more than four years (Ho et al., 2014) [26], which had an impact on the results. In some investigations, the exact time at which the postoperative BCVA was measured was not adequately described; this may have coincided with the end of the follow-up. This meta-analysis included only 350 eyes and aggregated the results from previously published studies; however, these results did not fulfill the standards for an effective meta-analysis. Therefore, additional clinical RCTs with larger sample sizes are warranted. Different FSIP techniques resulted in different sizes of preserved ILMs after surgery, which may have influenced our results. Although these limitations affect the reliability of the conclusions, the results are valuable for demonstrating the superiority of the FSIP technique.

In conclusion, the present meta-analysis of published studies showed that FSIP is an efficient and safe procedure for the treatment of the initial stages of MTM, with a higher rate of macular reattachment and a lower rate of MH formation than the standard ILMP method. Therefore, FSIP may be the preferred treatment for high myopia conditions such as MTM; however, for patients in the late and advanced stages, we need to implement other novel surgical options, which cannot yet be determined owing to a lack of available studies.