A Comparison of Face-Down Positioning and Adjustable Positioning After Pars Plana Vitrectomy for Macular Hole Retinal Detachment in High Myopia

Purpose To compare the anatomical and functional outcomes of macular hole retinal detachment (MHRD) in high myopia after pars plana vitrectomy (PPV) with face-down positioning and adjustable positioning. Methods Fifty-three eyes from 53 patients with MHRD were analyzed in this study. All patients received PPV with silicon oil for tamponade and then subdivided into 2 groups: 28 were included in a face-down positioning group and 25 were included in the adjustable positioning group. Patients were followed up for at least 6 months. The main outcome was the rate of anatomical macular hole (MH) closure and retinal reattachment. Secondary outcome measures were the best-corrected visual acuity and postoperative complications. Results There was no significant difference in the rate of MH closure (53.6 vs. 72.0%, p = 0.167) and retinal reattachment (100 vs. 96%, p = 0.472) between the face-down group and adjustable group. Compared with the mean preoperative best-corrected visual acuity (BCVA), the mean postoperative BCVA at the 6-month follow-up improved significantly in both groups (p = 0, both). But there was no significant difference in the mean postoperative BCVA (p = 0.102) and mean BCVA improvement (p = 0.554) at 6 months after surgery between the two groups. There was no significant difference in the high intraocular pressure (IOP) after surgery between the two groups (53.6 vs. 44%, p = 0.487). There were no other complications that occurred during the follow-up. Conclusion Adjustable positioning after PPV with silicon oil tamponade for MHRD repair is effective and safe. Face-down positioning does not seem to be necessary for all patients with MHRD.


INTRODUCTION
Macular hole retinal detachment (MHRD) is a serious vision impairment complication associated with high myopia. The pathogenesis of MHRD is not completely clear; however, it is believed that the tangential macular traction by the vitreoretinal interface, remnants of the cortical vitreous, inflexible internal limiting membrane (ILM), and the retinal vasculature is one of the factors (1,2). In addition, the weakened retinal adherence to the posterior pole caused by choroidal and retinal pigment epithelium (RPE) atrophy is also one of the factors (3). Since it was first described by Gonvers and Machemer, pars plana vitrectomy (PPV) procedures have been used in the surgical treatment of MHRD with high myopia (4). Vitrectomy combined posterior vitreous cortex removal, epiretinal membrane removal, and ILM removal, with gas or silicone oil tamponade to become the standard treatment for MHRD with a higher retinal reattachment rate (5). Since Michalewska et al. first presented the inverted ILM flap technique (6), modified techniques, such as temporal ILM flap or inverted ILM insertion, have been introduced to potentially improve the surgical outcomes in MH and MHRD (7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20), or to enhance the success rate in eyes with persistent full-thickness macular hole undergoing secondary PPV (21).
More than 90% of vitreoretinal surgeons worldwide recommend some period of face-down positioning after macular hole (MH) repair surgery (22). However, it is a tough challenge for most patients to keep a strict face-down positioning after operation for a long time. Elderly patients or patients with systemic diseases have serious difficulties persisting in the face-down positioning. Furthermore, some rare postoperative complications, like ulnar nerve palsies, pulmonary embolism, thrombophlebitis, and decubitus, would develop after a long period of face-down position (23,24). Multiple groups have reported the efficacy of postoperative positioning without the maintenance of a face-down positioning after vitrectomy for MH (22,(25)(26)(27)(28)(29)(30) and retinal detachment (RD) (31)(32)(33)(34)(35). However, MHRD is excluded from their observation. The purpose of the current study was to evaluate the 6-month outcomes of adjustable positioning compared to face-down positioning after PPV for MHRD in high myopia.

MATERIALS AND METHODS
This retrospective study analyzed a consecutive series of 53 eyes (53 patients) with MHRD in high myopia who underwent primary PPV between January 2018 and December 2019 at Qingdao Eye Hospital. The study followed the tenets of the Declaration of Helsinki and was approved by the Institutional Review Board of Qingdao Eye Hospital of Shandong First Medical University.
The inclusion criteria were as follows: (1) eyes with an axial length (AL) ≥26 mm; (2) the diagnosis of MRHD confirmed by optical coherence tomography (OCT) before surgery, and RD extending by more than 1 disk diameter around the full-thickness MH; and (3) the follow-up time is more than 6 months. Those eyes with previous vitreoretinal surgery, ocular trauma, and presence of peripheral retinal breaks before surgery, diabetic retinopathy, and other proliferative vitreoretinopathy were excluded.
The following general information was obtained for analysis: sex, age, systemic diseases, and bilaterality. All the patients accepted the preoperative and postoperative examinations that included best-corrected visual acuity (BCVA), intraocular pressure (IOP), slit-lamp examination, AL, B-ultrasound, fundus photography, and OCT. The decimal BCVA was converted to the logarithm of the minimum angle of resolution (logMAR) units for statistical analyses. The AL was measured using a Master 500 (Carl Zeiss, Germany). The area of the RD was determined by the images from a panoramic scanning laser ophthalmoscope (SLO) (Optos, Scotland), which was used to classify patients into those whose RD was within or beyond the vascular arcade. The presence of an MH, MH closure, and retina reattachment were evaluated in the OCT images (Optovue, USA).

Surgical Technique
Pars plana vitrectomy (PPV) procedures were performed using a standard 25-gauge 3-port system (Constellation, Alcon, USA). Core vitrectomy was performed by intravitreal injection of triamcinolone acetonide to visualize the vitreous gel and the posterior hyaloid. Peripheral vitreous base vitrectomy was performed under scleral depression. After being stained with indocyanine green (ICG) for 30 s, the ILM was peeled over the entire macular area and inserted into the MH to fill the hole. Fluid-gas exchange with drainage of subretinal fluid through the MH was performed. Finally, silicone oil was filled in all patients.
Patients were subdivided into two groups according to the postoperative positioning based on the recommendation of the surgeon. Face-down, as a routine treatment, meant keeping a face-down positioning for at least 12 h per day for at least 1 month after the surgery. Patients were encouraged to stay face-down during sleeping hours, as long as possible. In the adjustable group, patients were in a non-recumbent positioning during the daytime and fall asleep in the lateral positioning at night.
The primary endpoint was the MH closure and anatomical reattachment rate at 6 months after surgery. Secondary endpoints included BCVA change, change of IOP, and frequency of reported complications.

Statistical Analysis
Data were analyzed using the chi-square test and the Fisher exact test for categorical variables, and the ttest and the Mann-Whitney U test for numerical and ordinal variables. A P-value of 0.05 was considered statistically significant.

RESULTS
A total of 53 eyes of 53 patients (28 eyes in the face-down group and 25 eyes in the adjustable group) were analyzed. They There was no significant difference in the number of lens surgery and silicone oil volume between the groups (p > 0.05). The baseline parameters, status, and surgical procedure of the patients for the two groups are listed in Table 1.
We collected the 6-month visual and anatomic outcomes for all the patients (as shown in Table 2). There was no significant difference in the mean postoperative BCVA at 6 months after surgery between the two groups (p = 0.102). Compared with the mean preoperative BCVA, the mean postoperative BCVA at the 6-month follow-up improved significantly in both groups (p = 0 in both groups), but no significant difference in mean BCVA improvement was found between the two groups (p = 0.554).
The MH closed after the initial surgery in 15 (53.6%) eyes in the face-down group and 18 (72%) eyes in the adjustable group (Figure 1). The retinal reattached after initial surgery in 28 (100%) eyes in the face-down group (Figure 2) and 24 (96%) eyes in the adjustable group. There was no significant difference in the rate of MH closure (p = 0.167) and retinal reattachment (p = 0.472) between the two groups. Only one patient in the adjustable group did not achieve an MH closure and retinal reattachment. During the follow-up, she was unwilling to undergo another surgery, but the extent of retinal detachment gradually narrowed, and the MH was still not closed until 21 months after surgery (Figure 3). There were 15 eyes (53.6%)   and 11 eyes (44%) with high IOP after surgery in the two groups (p = 0.487). All eyes with high IOP were controlled within the normal range after the treatment with anti-glaucoma drugs, and no surgical intervention was performed. There were no retinal detachment and other complications occurred during the follow-up. In the study of Casswell et al. (34), findings suggest that facedown positioning was associated with a reduction in the rate and amplitude of postoperative retinal displacement after macularinvolving RD repair and with a reduction in binocular diplopia. Despite this, no association was found with visual acuity or postoperative distortion. However, none of these studies accepted RRD caused by MH in eyes with high degree myopia (−6 diopter or above). Pars plana vitrectomy (PPV) with ILM peeling and gas tamponade is an important surgical method for the MH. It has been reported that face-down positioning, following an MH surgery, provides no functional or anatomical benefit (36). Some scholars think that a postoperative non-supine positioning is adequate for all the patients with MH after surgery (25)(26)(27). Therefore, randomized controlled trials have been conducted to evaluate whether face-down positioning is necessary for recovery from MH surgery (37,38). The meta-analysis provides sufficient evidence that a non-face-down postoperative positioning is not inferior to a face-down positioning when the MH is smaller than 400 µm. Although a face-down postoperative positioning is highly recommended in MHs larger than 400 µm, the ideal visual improvement rate was not influenced by postoperative positioning (37). Zhu et al. (39) used a novel surgical protocol using vitrectomy, ILM peeling, and autologous blood clot covering the MH at the end of the MH surgery, which eliminated the gas tamponade and thus, the need for postoperative facedown positioning. Complete MH closure was achieved in all 18 eyes at the end of the follow-up period, and among them were five large MHs (minimum diameter > 400 mm).
Among myopic patients with MH, the incidence of RD increased as myopia worsened (1.1% RD in myopia under −3 D, 67.7% RD in myopia between −8, and −3.25 D, and 97.6% RD in myopia over −8.25 D) (1). AL elongation and posterior staphyloma contribute to the disparity in the length of the retina and the RPE-choroid-sclera complex, leading to the progression of retinal detachment (1,2). The articles on MHRD surgery published in the past 5 years are mostly from East Asia (7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) (as shown in Table 3). A total of 404 eyes in 403 patients were observed, including 331 women (82.1%) and 72 men (17.9%), and the majority of female patients were similar to the population data (40,41). If vitrectomy and ILM peeling have become the standard treatment for MHRD with a retinal reattachment rate of 91.5%, then the inverted ILM flap groups can achieve 97.3% (42). Otherwise, the inverted ILM insertion technique seems to improve the anatomical results in terms of MH closure rate with there being a tendency for better postoperative visual acuity in the inverted ILM insertion group (43). In these studies, none of them gave up the face-down positioning, and after filling with gas or silicone oil, the patients were asked to keep a prone positioning for 1-2 weeks and avoid supine positioning afterward.
Previous studies have reported that the healing of MHs begins within 24 h after the surgery, and the bridge configuration occurs around 3 days thereafter (44). The MHs were basically healed within 3 days after surgery, and those that were not healed within 3 days were still open during the 3-month follow-up (45). Seno et al. (46) observed and scored the compliance of the facedown positioning four times per day for 3 days post-surgery for patients who had undergone a primary vitrectomy and gas tamponade for MH or RRD. In fact, the compliance with the face-down positioning was considerably varied among patients, and some patients failed nearly or more than half the time, with considerable variation among patients and better adherence by the female patients, but without associations to the outcomes. When the eye is filled with gas or silicone oil after surgery, the tamponade agent can keep contact with the retina, exert the effect of surface tensions, and close the hole or break except in the lowest position of the vitreous cavity. The macular hole is located at the posterior pole of the eyeball and is not at the lowest position in the eye except during supine positioning. Silicone oil can close the macular hole in the non-facedown positioning. Based on these, it is enough for patients to avoid supine positioning.
To the best of our knowledge, this is the first study to address the issue of positioning after PPV and silicone oil tamponade surgery for MHRD. There was no significant difference in the MH closure, retinal reattachment, and postoperative BCVA between the face-down group and adjustable group in our study. In addition, better postoperative BCVA was gained in both the groups. The rate of MH closure and retinal reattachment was similar to previous reports (42). No complications occurred after the operation.
There are several limitations in our study that should be addressed. First, the study was non-randomized and lacked a randomized model for the positioning choice. Second, the followup period was probably short to observe the full recovery of foveal micro-structures. Third, all the eyes were tamponade by silicon oil because we lack the supply of C3F8.
In conclusion, the results of this study suggest that adjustable positioning after PPV with silicon oil tamponade for MHRD repair is effective and safe, and choosing an adjustable positioning over a face-down positioning approach does not reduce the possibility of MH closure, retinal reattachment, and improvement of visual acuity or significantly increase the risk of complications. Face-down positioning does not seem to be necessary for all patients with MHRD. A larger and prospective randomized controlled trial study is recommended to determine the long-term outcomes of adjustable positioning after PPV surgery for MHRD.

DATA AVAILABILITY STATEMENT
The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.

ETHICS STATEMENT
The studies involving human participants were reviewed and approved by Institutional Review Board of Qingdao Eye Hospital of Shandong First Medical University. The patients/participants provided their written informed consent to participate in this study.

AUTHOR CONTRIBUTIONS
Material preparation, data collection, and analysis were performed by YG and TR. The first draft of the manuscript was written by JL. All authors contributed to the conception and design of the study, provided comments on the manuscript, and read and approved the final manuscript.