Prognostic Factors of Fluid-gas Exchange Outcomes in Patients with Failed Primary Surgery for Idiopathic Macular Hole

Prognostic Factors of Fluid-gas Exchange Outcomes in Patients with Failed Primary Surgery for Idiopathic Macular Hole | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Prognostic Factors of Fluid-gas Exchange Outcomes in Patients with Failed Primary Surgery for Idiopathic Macular Hole You Hyun Lee, Ji Hye Jang, Soo Jin Lee, Yu Cheol Kim This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-149595/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract This retrospective study aimed to evaluate prognostic factors associated with the success of fluid-gas exchange in patients with failed primary idiopathic macular hole (IMH) surgery. Outcomes of the fluid-gas exchange were categorised as unclosed, or U-type, V-type, or W-type closure. Patients were divided into the successful and unsuccessful groups according to the absence or presence of bare retinal pigment epithelium, respectively, following fluid-gas exchange. Demographics, baseline characteristics, and pre-procedure characteristics were assessed. A total of 19 eyes in 19 patients that had failed IMH surgery and then underwent fluid-gas exchange were included. Of those, 18 eyes had MH closure (successful, 15 eyes; unsuccessful, three eyes). One eye was unclosed after fluid-gas exchange; therefore, the patient underwent additional vitrectomy for MH closure (unsuccessful). The successful group showed significantly lower pre-procedure base diameters; higher baseline and pre-procedure macular hole index, hole form factor, and tractional hole index values; and lower baseline and pre-procedure minimum diameter and diameter hole index values. Moreover, a better visual prognosis was observed in the successful group. These results suggest that indices predicting favourable results of primary surgery for IMH are useful to predict the success of fluid-gas exchange in patients with failed primary MH surgery. Health Economics & Outcomes Research Medical Genetics Scientific Communication fluid-gas exchange idiopathic macular hole (IMH) U-type V-type W-type Figures Figure 1 Introduction A macular hole (MH) is a full-thickness defect in the fovea. Since Kelly and Wendel 1 reported the successful closure of an MH using pars plana vitrectomy with fluid-gas exchange, this surgical method combined with internal limiting membrane peeling has become the standard treatment for MH, showing an anatomical closure rate of more than 90% 2,3 . Various optical coherence tomography (OCT) parameters, such as the hole form factor (HFF), base diameter (BD), and macular hole volume (MHV), are prognostic factors that determine functional and anatomical success in primary MH surgery 4 , 5 . Unfortunately, about 10% of all MH surgeries fail and, therefore, may require additional procedures. Intravitreal gas injection or fluid-gas exchange using octafluoropropane (C 3 F 8 ) or sulfur hexafluoride (SF 6 ) for MH closure has shown favourable results in such cases 6 , 7 . However, some of them with a failed primary MH surgery patients treated with additional procedure of injection or fluid-gas exchange have needed additional surgery to close the MH 8 . To the best of our knowledge, there have been no studies regarding the effectiveness of indices in predicting the outcomes of a fluid-gas exchange procedure following a failed primary MH surgery. Therefore, we aimed to evaluate the prognostic factors associated with the success of fluid-gas exchange after a failed primary idiopathic macular hole (IMH) surgery. Results Demographic characteristics A total of 19 eyes in 19 patients were included in this study. The fluid-gas exchange procedure following the failed primary IMH surgery resulted in MH closure in 18 eyes (successful in 15 eyes and unsuccessful in three eyes, Fig. 1 ). The MH was unclosed in one eye after the fluid-gas exchange, and the patient underwent additional vitrectomy to close the MH (unsuccessful). All patients in the successful group showed a U-type closure, whereas all in the unsuccessful group presented a W-type closure 9 . The demographic data of all patients are shown in Table 1 . The mean age was 67 ± 6 years in the successful group and 73 ± 7 years in the unsuccessful group; the difference was not statistically significant. Similarly, the affected eye and sex did not differ significantly between the two groups. Table 1 Demographic and baseline clinical characteristics of the successful and unsuccessful groups of patients with unclosed macular hole treated with fluid-gas exchange. Parameters Successful group (n = 15) Unsuccessful group (n = 4) p value Age in years, mean (SD) 67 (6) 73 (7) 0.152 Sex, n (%) male 6 (40.0%) 1 (25.0%) 1.000 Laterality, n (%) right eye 10 (66.7%) 2 (50.0%) 0.603 Symptom duration, days, mean (SD) 57 (59) 87 (56) 0.262 Total follow-up period, months, mean (SD) 22 (6) 29 (6) 0.100 Baseline BCVA, logMAR, mean (SD) 0.85 (0.22) 0.70 (0.14) 0.185 Baseline IOP, mmHg, mean (SD) 14.5 (3.8) 14.0 (2.2) 1.000 Baseline spherical equivalent, mean (SD) 1.34 (1.59) 2.22 (1.42) 0.469 Baseline lens status, phakic, n (%) 10 (66.7%) 3 (75.0%) 1.000 Baseline central subfield retinal thickness, µm, mean (SD) 346.40 (48.62) 320.25 (132.51) 0.596 Baseline minimum diameter, µm, mean (SD) 450.20 (68.80) 825.25 (140.19) 0.001 * Baseline base diameter, µm, mean (SD) 1095.87 (475.92) 1248.50 (280.03) 0.357 Baseline height, µm, mean (SD) 562.53 (175.18) 489.50 (157.47) 0.469 Baseline axial length, mm, mean (SD) 22.76 (0.37) 22.73 (0.32) 0.736 Baseline macular hole index, mean (SD) 0.550 (0.153) 0.386 (0.040) 0.009 * Baseline hole form factor, mean (SD) 0.868 (0.146) 0.463 (0.204) 0.009 * Baseline diameter hole index, mean (SD) 0.476 (0.171) 0.669 (0.067) 0.014 * Baseline tractional hole index, mean (SD) 1.272 (0.437) 0.587 (0.128) 0.001 * Baseline macular hole volume, mm 3 , mean (SD) 0.181 (0.016) 0.231 (0.013) 0.262 Type of primary surgery, vitrectomy alone, n (%) 12 (80.0%) 2 (50.0%) 0.272 Type of primary gas tamponade, SF 6 , n (%) 6 (40.0%) 3 (75.0%) 0.303 Percentage of primary gas tamponade, mean (SD) 18 (4) 19 (2) 0.411 * Statistically significant as calculated using the Mann-Whitney U test. BCVA , best-corrected visual acuity, IOP , intraocular pressure, SD , standard deviation. Baseline clinical characteristics of the successful and unsuccessful groups A comparison of the baseline clinical characteristics between the two groups is shown in Table 1 . A longer duration of decreased visual acuity was observed in the unsuccessful group (87 ± 56 days); however, this difference was not statistically significant, compared with that in the successful group (57 ± 59 days). The total follow-up period, baseline best-corrected visual acuity (BCVA), mean intraocular pressure (IOP), mean spherical equivalent, number of phakic patients at baseline, gas type of primary tamponade, percentage of primary gas tamponade, and mean central subfield retinal thickness (CSRT) at baseline were not significantly different between the two groups. The mean baseline minimum diameter (MD) was significantly lower in the successful group (363.87 ± 124.95 µm) than in the unsuccessful group (612.00 ± 11.43 µm); however, no difference was observed in the mean baseline BD between the two groups. The mean MH height also showed nonsignificant differences between the two groups. A significantly higher mean baseline macular hole index (MHI) was observed in the successful group (0.558 ± 0.159) than in the unsuccessful group (0.386 ± 0.041). The mean baseline HFF was significantly higher in the successful group than in the unsuccessful group (0.876 ± 0.154 versus 0.463 ± 0.204). The mean baseline diameter hole index (DHI) was significantly lower in the successful group (0.470 ± 0.182) than in the unsuccessful group (0.669 ± 0.067). The mean baseline tractional hole index (THI) was significantly higher in the successful group than in the unsuccessful group (1.404 ± 0.843 versus 0.587 ± 0.129). However, the mean baseline MHV was not different between the two groups. Comparison of pre-procedure clinical characteristics between the successful and unsuccessful groups A comparison of the pre-procedure clinical characteristics between the two groups is shown in Table 2 . A longer interval between primary surgery and fluid-gas exchange was observed in the successful group (17 ± 8 days) than in the unsuccessful group (12 ± 3 days); however, this difference was not statistically significant. The mean pre-procedure CSRT also showed no difference between the successful group and unsuccessful group. Both mean pre-procedure MD and mean pre-procedure BD values were significantly lower in the successful group (276.13 ± 89.59 µm versus 633.00 ± 182.42 µm, and 638.20 ± 274.34 µm versus 831.00 ± 113.18 µm, respectively). In contrast, the mean pre-procedure MH height was not significantly different between the two groups. A significantly higher mean pre-procedure MHI was observed in the successful group (0.624 ± 0.193) than in the unsuccessful group (0.452 ± 0.054). The mean pre-procedure HFF was significantly higher in the successful group than in the unsuccessful group (0.881 ± 0.204 versus 0.511 ± 0.140). The mean baseline DHI was significantly lower in the successful group (0.474 ± 0.161) than in the unsuccessful group (0.751 ± 159), whereas the mean baseline THI was significantly higher in the successful group than in the unsuccessful group (1.419 ± 0.561 versus 0.640 ± 0.245). Moreover, the mean baseline MHV was significantly lower in the successful group than in the unsuccessful group (0.411 ± 0.334 versus 1.032 ± 0.426). The type of procedure gas (SF 6 ) did not differ between the two groups. Table 2 Comparison of pre-procedure clinical characteristics between the successful and unsuccessful groups of patients with unclosed macular hole treated with fluid-gas exchange. Parameters Successful group (n = 15) Unsuccessful group (n = 4) p value Interval between primary surgery and fluid-gas exchange, days, mean (SD) 17 (8) 12 (3) 0.357 Pre-procedure central subfield retinal thickness, µm, mean (SD) 307.00 (31.90) 306.25 (18.84) 0.885 Pre-procedure minimum diameter, µm, mean (SD) 276.13 (89.59) 633.00 (182.42) 0.001 * Pre-procedure base diameter, µm, mean (SD) 638.20 (274.34) 831.00 (113.18) 0.049 * Pre-procedure height, µm, mean (SD) 364.00 (105.81) 371.75 (18.63) 0.810 Pre-procedure macular hole index, mean (SD) 0.624 (0.193) 0.452 (0.054) 0.037 * Pre-procedure hole form factor, mean (SD) 0.881 (0.204) 0.511 (0.140) 0.004 * Pre-procedure diameter hole index, mean (SD) 0.474 (0.161) 0.751 (0.159) 0.006 * Pre-procedure tractional hole index, mean (SD) 1.419 (0.561) 0.640 (0.245) 0.006 * Pre-procedure macular hole volume, mm 3 , mean (SD) 0.411 (0.334) 1.032 (0.426) 0.014 * Type of procedure gas, SF 6 , n (%) 4 (26.7%) 1 (25.0%) 1.000 * Statistically significant as calculated using the Mann-Whitney U test. SD , standard deviation. Visual prognosis of the successful and unsuccessful groups The successful group presented significantly better final BCVA values (0.33 ± 0.18 logMAR) than the unsuccessful group (0.78 ± 0.15 logMAR, Table 3 ). Furthermore, the final BCVA in the successful group was significantly improved compared to baseline BCVA (0.85 ± 0.22 logMAR), whereas the unsuccessful group demonstrated a poorer final BCVA compared to baseline (0.70 ± 0.14 logMAR); however, this difference was not statistically significant (Table 3 ). Table 3 Comparison of baseline and final best-corrected visual acuity between the successful and unsuccessful groups of patients with unclosed macular hole treated with fluid-gas exchange. Parameters Baseline Final p value Best-corrected visual acuity in the successful group, logMAR, mean ± (SD) 0.85 (0.22) 0.33 (0.18) 0.001 * Best-corrected visual acuity in the unsuccessful group, logMAR, mean ± (SD) 0.70 (0.14) 0.78 (0.15) 0.083 p value 0.185 0.001 * * Statistically significant as calculated using the Mann-Whitney U test or Wilcoxon signed-rank test. SD , standard deviation. Discussion This study retrospectively analysed the baseline and pre-procedure characteristics of patients with primary unclosed MH treated with fluid-gas exchange and showed that several baseline and pre-procedure OCT parameters were associated with the success of the fluid-gas exchange procedure after a failed primary IMH surgery. Various studies have reported relationships between preoperative OCT parameters and the prognosis of MH patients. Shpak et al . 10 demonstrated that a higher preoperative CSRT is related to the anatomical success of surgical IMH treatment. Similarly, our study showed increased baseline and pre-procedure CSRT values in the successful group compared to those in the unsuccessful group, although this difference was not statistically significant. Wakely et al . 11 reported that the parameters BD, MH inner opening, and MD were related to the anatomical and functional success in MH surgery. In patients with primary unclosed IMH treated with fluid-gas exchange, a smaller baseline MD, pre-procedure MD, and pre-procedure BD were also related to success. Kusuhara et al . 12 showed that IMH patients with MHI values ≥ 0.5 had a better postoperative BCVA than those with MHI values < 0.5. In this study, baseline and pre-procedure MHI values ≥ 0.5 were observed in the successful group with a better final BCVA than those in the unsuccessful group (baseline and pre-procedure MHI < 0.5). Several studies have reported that a higher HFF increases the closure rate and improves the postoperative visual outcome in MH patients 4 . In agreement with this publication, significantly higher baseline and pre-procedure HFF values with better final BCVA were observed in the successful group of our study. Ruiz-Moreno et al . 13 and Dai et al . 14 demonstrated that a higher THI is correlated with good visual prognosis, whereas DHI is not. However, our study revealed that both higher THI and lower DHI were related to the success of the fluid-gas exchange in patients with primary unclosed MH. Unsal et al . 5 reported that a higher MHV is associated with a poorer postoperative BCVA, whereas Ozturk et al . 15 detected no significant correlation. In this study, no difference in baseline MHV was noted between the two groups, but a significantly higher pre-procedure MHV was observed in the unsuccessful group. These findings suggest that MH indicators that are related to the success of primary surgery tend to be also correlated with the success of fluid-gas exchange in patients with failed primary MH treatment. Zou et al . 16 reported that a shorter symptom duration is associated with an earlier reconstruction of the external limiting membrane, resulting in better visual outcomes. Shorter symptom duration was also observed in the successful group of our study; however, compared with the unsuccessful group, the difference was not statistically significant. The current consensus recommends internal limiting membrane peeling during a MH surgery; however, the face-down position after primary vitrectomy remains controversial 17 . Nonetheless, a previous meta-analysis concluded that the face-down position is highly recommended when the MH size exceeds 400 µm 18 . In this study, the MH size in all patients at baseline was > 400 µm, and all patients were positioned face-down after the primary vitrectomy. Among them, 94.74% (18 of 19 patients) had MH closure after the fluid-gas exchange procedure, with ≥ 7 days of additional period in face-down position. These findings highlight that an inadequate period of gas tamponade with face-down position might be associated with the failure of primary surgery in IMH patients, and the fluid-gas exchange procedure with the additional period in face-down position is useful in these failed primary IMH patients. One previous study mentioned that SF 6 and C 3 F 8 gas tamponades during surgery show similar MH closure rates 19 . In agreement with these findings, we observed that the type of gas used for the fluid-gas exchange was not different between the successful and unsuccessful groups. This study has some limitations. First, the retrospective design may have resulted in a patient selection bias. Second, this study included only a small number of patients. Therefore, further studies with larger numbers of patients with failed primary IMH treatment will be needed. Despite these limitations, to the best of our knowledge, this is the first study to evaluate the factors associated with the success in patients with failed primary IMH surgery treated with fluid-gas exchange. In conclusion, lower pre-procedure BD, lower baseline and pre-procedure DHI and MD, and higher baseline and pre-procedure MHI, HF, and THI values are associated with the success of fluid-gas exchange in patients with failed primary IMH treatment. These results suggest that indices predicting the success of primary IMH surgery may also be useful to predict the success of fluid-gas exchange in patients with failed primary surgery. Methods Study design and subjects This study was designed as a retrospective, comparative case series conducted in a single hospital. The study adhered to the tenets of the Declaration of Helsinki and was approved by the institutional review board of Keimyung University Dongsan Hospital (IRB no. 2020-12-069). The patients signed informed consent for the use of their data. We retrospectively reviewed the electronic medical records of patients with a history of a failed primary IMH surgery who were treated with fluid-gas exchange between January 2013 and December 2019. The patients with at least 6 months of follow-up period after the procedure were enrolled in the study. The exclusion criteria were as follows: myopia > 6 dioptres, presence of rhegmatogenous retinal detachment, diabetic retinopathy, age-related macular degeneration, or a history of previous vitrectomy due to causes other than IMH. All patients had a full-thickness IMH and underwent primary vitrectomy with internal limiting membrane peeling using the inverted flap technique. Cataract surgery was performed simultaneously when the cataract impaired posterior visualisation. The patients were instructed to remain in a face-down position for ≥ 7 days. The fluid-gas exchange procedure was performed on 19 eyes in which an unclosed MH was noted in the spectral-domain OCT (Spectralis OCT/SLO; Ophthalmic Technologies, Toronto, Ontario, Canada) or swept-source OCT (DRI OCT-1; Topcon, Tokyo, Japan) during the follow-up period. The procedure was based on a previous report by Jang et al . 20 , and the patients were instructed to stay in the face-down position for 7 days. The type and percentage of gas used in the primary surgery were determined by the surgeon’s preference. During the fluid-gas exchange, 16% of SF 6 gas or 14% of C 3 F 8 gas was used. All aforementioned surgical and other procedures were performed by a single clinician (Y.C.K.). Based on the classification by Imai et al. 6 , the outcomes of the fluid-gas exchange procedure were classified as U-type closure, V-type closure, W-type closure, or unclosed. The patients were divided into the successful and unsuccessful groups according to the absence or presence of bare retinal pigment epithelium after the fluid-gas exchange procedure, respectively (Fig. 1 ). Demographic and clinical characteristics were compared between the two groups to assess the prognostic factors. Clinical data collection The demographic characteristics including age, sex, and laterality were assessed in all patients. Furthermore, the duration of decreased visual acuity, baseline IOP measured by a non-contact tonometer (Canon TX-20, Canon Inc, Kanagawa, Japan), spherical equivalent, lens status (phakic or pseudophakic), axial length, type of primary surgery (vitrectomy alone or combined cataract surgery) with the type of gas and the percentage used for tamponade during primary surgery, interval period between the primary surgery and fluid-gas exchange, and the type and percentage of gas used in the fluid-gas exchange were recorded. The baseline and final logMAR BCVA values were also assessed. OCT images of all patients were recorded at baseline, pre-procedure, and post-procedure until the last follow-up. CSRT, BD, MD, MH height, MHV height, left arm length, and right arm length were measured using the OCT software measuring tool at baseline and pre-procedure. In addition, the MHI based on the publication by Kusuhara et al . 12 , the THI and DHI by Ruiz-Moreno et al . 13 , the HFF by Ullrich et al . 4 , and the MHV by Ozturk et al . 15 were calculated. Statistical methods Data were calculated as the mean ± standard deviation (SD) or n (%; e.g., number of eyes). Statistical analyses were performed using Statistical Package for the Social Sciences version 12.0 (IBM, Chicago, IL, USA). Between-group differences in age, symptom duration, total follow-up period, baseline and final BCVA, baseline IOP, baseline spherical equivalent, percentages of gas tamponade used in primary surgery and fluid-gas exchange, baseline axial length, and baseline and pre-procedure values of BD, MD, MH height, MHI, HFF, DHI, THI, and MHV were compared using the Mann-Whitney U test. Categorical variables, such as sex, affected eye, lens status, type of surgery, and type of gas used in the primary surgery and fluid-gas exchange were compared using the chi-square test or Fisher’s exact test. The comparison of baseline and post-procedure BCVA between the two groups was performed using the Wilcoxon signed-rank test. All the tests had two-tailored critical regions for a significance level of 0.05. Declarations Data availability The datasets generated and/or analysed during the present study are available from the corresponding author on reasonable request. Acknowledgements This research was supported by the Bisa Research Grant of Keimyung University in 2020. The sponsor had no role in the design or conduct of this research. Author contributions Y.H.L. conceived and designed the study and wrote the manuscript. S.J.L. was responsible for data curation. J.H.J. reviewed the manuscript. Y.C.K. initiated and supervised the project and reviewed the manuscript. All authors read and approved the final manuscript. Competing interests The authors declare no competing interests. References Kelly, N. E. & Wendel, R. T. Vitreous surgery for idiopathic macular holes. Results of a pilot study. Arch. Ophthalmol. 109, 654–659 (1991). Smiddy, W. E., Feuer, W. & Cordahi, G. Internal limiting membrane peeling in macular hole surgery. Ophthalmology 108, 1471–1476 (2001). Brooks, H. L., Jr. Macular hole surgery with and without internal limiting membrane peeling. Ophthalmology 107, 1939–1948 (2000). Ullrich, S. et al. Macular hole size as a prognostic factor in macular hole surgery. Br. J. Ophthalmol. 86, 390–393 (2002). Unsal, E., Cubuk, M. O. & Ciftci, F. Preoperative prognostic factors for macular hole surgery: Which is better? Oman J. Ophthalmol. 12, 20–24 (2019). Imai, M., Gotoh, T. & Iijima, H. Additional intravitreal gas injection in the early postoperative period for an unclosed macular hole treated with internal limiting membrane peeling. Retina 25, 158–161 (2005). Ohana, E. & Blumenkranz, M. S. Treatment of reopened macular hole after vitrectomy by laser and outpatient fluid-gas exchange. Ophthalmology 105, 1398–1403 (1998). Iwase, T. & Sugiyama, K. Additional gas injection after failed macular hole surgery with internal limiting membrane peeling. Clin. Exp. Ophthalmol. 35, 214–219 (2007). Imai, M., Iijima, H., Gotoh, T. & Tsukahara, S. Optical coherence tomography of successfully repaired idiopathic macular holes. Am. J. Ophthalmol. 128, 621–627 (1999). Shpak, A. A., Shkvorchenko, D. O., Sharafetdinov, I. K. & Yukhanova, O. A. Predicting anatomical results of surgical treatment of idiopathic macular hole. Int. J. Ophthalmol. 9, 253–257 (2016). Wakely, L., Rahman, R. & Stephenson, J. A comparison of several methods of macular hole measurement using optical coherence tomography, and their value in predicting anatomical and visual outcomes. Br. J. Ophthalmol. 96, 1003–1007 (2012). Kusuhara, S. et al. Prediction of postoperative visual outcome based on hole configuration by optical coherence tomography in eyes with idiopathic macular holes. Am. J. Ophthalmol. 138, 709–716 (2004). Ruiz-Moreno, J. M. et al. Optical coherence tomography predictive factors for macular hole surgery outcome. Br. J. Ophthalmol. 92, 640–644 (2008). Dai, Y. M., Shen, J., Li, J. K., Jin, X. H. & Li, Y. M. [Optical coherence tomography predictive factors for idiopathic macular hole surgery outcome]. [Zhonghua yan ke za zhi] Chin. J. Ophthalmol. 49, 807–811 (2013). Ozturk, T. et al. Effect of macular hole volume on postoperative central macular thickness. Arq. Bras. Oftalmol. 79, 137–142 (2016). Zou, J.-L. & Zeng, J. The macular microstructure repair and predictive factors of surgical outcomes after vitrectomy for idiopathic macular hole. Int . J . Ophthalmol . 12, 852–857 (2019). Nadal, J., Delas, B. & Piñero, A. Vitrectomy without face-down posturing for idiopathic macular holes. Retina 32, 918–921 (2012). Ye, T. et al. Macular hole surgery recovery with and without face-down posturing: a meta-analysis of randomized controlled trials. BMC Ophthalmol. 19, 265 (2019). Modi, A., Giridhar, A. & Gopalakrishnan, M. Sulfurhexafluoride (SF 6 ) versus perfluoropropane (C 3 F 8 ) gas as tamponade in macular hole surgery. Retina 37, 283–290 (2017). Jang, J. H., Kim, Y. C. & Kim, K. S. The efficacy of fluid-gas exchange for the treatment of postvitrectomy retinal detachment. Korean J. Ophthalmol. 23, 253–258 (2009). Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-149595","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":8442173,"identity":"ce12869a-9f04-4461-a041-e2caca77da05","order_by":0,"name":"You Hyun Lee","email":"","orcid":"","institution":"Keimyung University Dongsan Medical Center","correspondingAuthor":false,"prefix":"","firstName":"You","middleName":"Hyun","lastName":"Lee","suffix":""},{"id":8442174,"identity":"04521cba-9660-493c-a540-b0eed9970628","order_by":1,"name":"Ji Hye Jang","email":"","orcid":"","institution":"Keimyung University Dongsan Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Ji","middleName":"Hye","lastName":"Jang","suffix":""},{"id":8442175,"identity":"87381bdf-8e0f-45b9-a6f8-6cd1bc5f54d2","order_by":2,"name":"Soo Jin Lee","email":"","orcid":"","institution":"Keimyung University Dongsan Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Soo","middleName":"Jin","lastName":"Lee","suffix":""},{"id":8442176,"identity":"a7ccdd13-c916-4332-8c24-00cb3c229432","order_by":3,"name":"Yu Cheol Kim","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAu0lEQVRIiWNgGAWjYJACCYYKZhg7gVgtZ0jWwthGihZ+ieSDtyvnWdvrth9gfFzBkJZPUIvkjLRky7Pb0hO3nUlgNjzDkGPZQEiLwY0cM8nGbYcTzG4wsEk2MFQYELTF/kb+N8nGOYftiddiIJHDJtnYcJhxG0RLDmEtEmeeGVs2HAP5JbHZsMEgjbAW/vbkhzcbaqztzY4fPviwoSKZsBYGgQQYi7EB6E7CGoDWHCBG1SgYBaNgFIxoAAA8xjiheSS8iAAAAABJRU5ErkJggg==","orcid":"","institution":"Keimyung University Dongsan Medical Center","correspondingAuthor":true,"prefix":"","firstName":"Yu","middleName":"Cheol","lastName":"Kim","suffix":""}],"badges":[],"createdAt":"2021-01-18 01:44:05","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-149595/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-149595/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":5131388,"identity":"5f623ccd-3eb8-4a87-af13-9712a64733d9","added_by":"auto","created_at":"2021-01-20 18:00:14","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":1392459,"visible":true,"origin":"","legend":"Optical coherence tomography images of successful and unsuccessful anatomical outcomes after fluid-gas exchange. (a) Example of a successful anatomical outcome showing the absence of bare retinal pigment epithelium. (b) An unsuccessful outcome showing the presence of bare retinal pigment epithelium.","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-149595/v1/5a67f68d7cd247d54dd3bc07.png"},{"id":13650161,"identity":"910a6b8d-5550-4c1a-a34f-af21f4d251a4","added_by":"auto","created_at":"2021-09-17 09:39:59","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1196600,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-149595/v1/e5c6884e-a95c-4b5c-ac64-fa237bfb87ae.pdf"}],"financialInterests":"","formattedTitle":"\u003cp\u003ePrognostic Factors of Fluid-gas Exchange Outcomes in Patients with Failed Primary Surgery for Idiopathic Macular Hole\u003c/p\u003e","fulltext":[{"header":"Introduction","content":" \u003cp\u003eA macular hole (MH) is a full-thickness defect in the fovea. Since Kelly and Wendel\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e reported the successful closure of an MH using pars plana vitrectomy with fluid-gas exchange, this surgical method combined with internal limiting membrane peeling has become the standard treatment for MH, showing an anatomical closure rate of more than 90%\u003csup\u003e2,3\u003c/sup\u003e. Various optical coherence tomography (OCT) parameters, such as the hole form factor (HFF), base diameter (BD), and macular hole volume (MHV), are prognostic factors that determine functional and anatomical success in primary MH surgery\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e,\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eUnfortunately, about 10% of all MH surgeries fail and, therefore, may require additional procedures. Intravitreal gas injection or fluid-gas exchange using octafluoropropane (C\u003csub\u003e3\u003c/sub\u003eF\u003csub\u003e8\u003c/sub\u003e) or sulfur hexafluoride (SF\u003csub\u003e6\u003c/sub\u003e) for MH closure has shown favourable results in such cases\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e,\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e. However, some of them with a failed primary MH surgery patients treated with additional procedure of injection or fluid-gas exchange have needed additional surgery to close the MH\u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e. To the best of our knowledge, there have been no studies regarding the effectiveness of indices in predicting the outcomes of a fluid-gas exchange procedure following a failed primary MH surgery. Therefore, we aimed to evaluate the prognostic factors associated with the success of fluid-gas exchange after a failed primary idiopathic macular hole (IMH) surgery.\u003c/p\u003e "},{"header":"Results","content":"\u003ch2\u003eDemographic characteristics\u003c/h2\u003e\n\u003cp\u003eA total of 19 eyes in 19 patients were included in this study. The fluid-gas exchange procedure following the failed primary IMH surgery resulted in MH closure in 18 eyes (successful in 15 eyes and unsuccessful in three eyes, Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e). The MH was unclosed in one eye after the fluid-gas exchange, and the patient underwent additional vitrectomy to close the MH (unsuccessful). All patients in the successful group showed a U-type closure, whereas all in the unsuccessful group presented a W-type closure\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. The demographic data of all patients are shown in Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e. The mean age was 67\u0026thinsp;\u0026plusmn;\u0026thinsp;6\u0026nbsp;years in the successful group and 73\u0026thinsp;\u0026plusmn;\u0026thinsp;7\u0026nbsp;years in the unsuccessful group; the difference was not statistically significant. Similarly, the affected eye and sex did not differ significantly between the two groups.\u0026nbsp;\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003ctable id=\"Tab1\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eDemographic and baseline clinical characteristics of the successful and unsuccessful groups of patients with unclosed macular hole treated with fluid-gas exchange.\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eParameters\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eSuccessful group\u003c/p\u003e\n\u003cp\u003e(n\u0026thinsp;=\u0026thinsp;15)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eUnsuccessful group\u003c/p\u003e\n\u003cp\u003e(n\u0026thinsp;=\u0026thinsp;4)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003ep\u003c/em\u003e value\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eAge in years, mean (SD)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e67 (6)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e73 (7)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.152\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSex, n (%) male\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e6 (40.0%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1 (25.0%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e1.000\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eLaterality, n (%) right eye\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e10 (66.7%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e2 (50.0%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.603\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSymptom duration, days, mean (SD)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e57 (59)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e87 (56)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.262\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eTotal follow-up period, months, mean (SD)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e22 (6)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e29 (6)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.100\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBaseline BCVA, logMAR, mean (SD)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.85 (0.22)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.70 (0.14)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.185\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBaseline IOP, mmHg, mean (SD)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e14.5 (3.8)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e14.0 (2.2)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e1.000\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBaseline spherical equivalent, mean (SD)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1.34 (1.59)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e2.22 (1.42)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.469\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBaseline lens status, phakic, n (%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e10 (66.7%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e3 (75.0%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e1.000\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBaseline central subfield retinal thickness, \u0026micro;m, mean (SD)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e346.40 (48.62)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e320.25 (132.51)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.596\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBaseline minimum diameter, \u0026micro;m, mean (SD)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e450.20 (68.80)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e825.25 (140.19)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.001\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBaseline base diameter, \u0026micro;m, mean (SD)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1095.87 (475.92)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1248.50 (280.03)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.357\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBaseline height, \u0026micro;m, mean (SD)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e562.53 (175.18)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e489.50 (157.47)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.469\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBaseline axial length, mm, mean (SD)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e22.76 (0.37)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e22.73 (0.32)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.736\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBaseline macular hole index, mean (SD)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.550 (0.153)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.386 (0.040)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.009\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBaseline hole form factor, mean (SD)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.868 (0.146)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.463 (0.204)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.009\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBaseline diameter hole index, mean (SD)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.476 (0.171)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.669 (0.067)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.014\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBaseline tractional hole index, mean (SD)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1.272 (0.437)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.587 (0.128)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.001\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBaseline macular hole volume, mm\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e, mean (SD)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.181 (0.016)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.231 (0.013)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.262\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eType of primary surgery, vitrectomy alone, n (%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e12 (80.0%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e2 (50.0%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.272\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eType of primary gas tamponade, SF\u003csub\u003e6\u003c/sub\u003e, n (%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e6 (40.0%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e3 (75.0%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.303\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePercentage of primary gas tamponade, mean (SD)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e18 (4)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e19 (2)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.411\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003ctfoot\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"4\"\u003e\u003csup\u003e*\u003c/sup\u003eStatistically significant as calculated using the Mann-Whitney U test.\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"4\"\u003e\u003cem\u003eBCVA\u003c/em\u003e, best-corrected visual acuity, \u003cem\u003eIOP\u003c/em\u003e, intraocular pressure, \u003cem\u003eSD\u003c/em\u003e, standard deviation.\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tfoot\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003ch2\u003eBaseline clinical characteristics of the successful and unsuccessful groups\u003c/h2\u003e\n\u003cp\u003eA comparison of the baseline clinical characteristics between the two groups is shown in Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e. A longer duration of decreased visual acuity was observed in the unsuccessful group (87\u0026thinsp;\u0026plusmn;\u0026thinsp;56 days); however, this difference was not statistically significant, compared with that in the successful group (57\u0026thinsp;\u0026plusmn;\u0026thinsp;59 days). The total follow-up period, baseline best-corrected visual acuity (BCVA), mean intraocular pressure (IOP), mean spherical equivalent, number of phakic patients at baseline, gas type of primary tamponade, percentage of primary gas tamponade, and mean central subfield retinal thickness (CSRT) at baseline were not significantly different between the two groups. The mean baseline minimum diameter (MD) was significantly lower in the successful group (363.87\u0026thinsp;\u0026plusmn;\u0026thinsp;124.95\u0026nbsp;\u0026micro;m) than in the unsuccessful group (612.00\u0026thinsp;\u0026plusmn;\u0026thinsp;11.43\u0026nbsp;\u0026micro;m); however, no difference was observed in the mean baseline BD between the two groups. The mean MH height also showed nonsignificant differences between the two groups. A significantly higher mean baseline macular hole index (MHI) was observed in the successful group (0.558\u0026thinsp;\u0026plusmn;\u0026thinsp;0.159) than in the unsuccessful group (0.386\u0026thinsp;\u0026plusmn;\u0026thinsp;0.041). The mean baseline HFF was significantly higher in the successful group than in the unsuccessful group (0.876\u0026thinsp;\u0026plusmn;\u0026thinsp;0.154 versus 0.463\u0026thinsp;\u0026plusmn;\u0026thinsp;0.204). The mean baseline diameter hole index (DHI) was significantly lower in the successful group (0.470\u0026thinsp;\u0026plusmn;\u0026thinsp;0.182) than in the unsuccessful group (0.669\u0026thinsp;\u0026plusmn;\u0026thinsp;0.067). The mean baseline tractional hole index (THI) was significantly higher in the successful group than in the unsuccessful group (1.404\u0026thinsp;\u0026plusmn;\u0026thinsp;0.843 versus 0.587\u0026thinsp;\u0026plusmn;\u0026thinsp;0.129). However, the mean baseline MHV was not different between the two groups.\u003c/p\u003e\n\u003ch2\u003eComparison of pre-procedure clinical characteristics between the successful and unsuccessful groups\u003c/h2\u003e\n\u003cp\u003eA comparison of the pre-procedure clinical characteristics between the two groups is shown in Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e. A longer interval between primary surgery and fluid-gas exchange was observed in the successful group (17\u0026thinsp;\u0026plusmn;\u0026thinsp;8 days) than in the unsuccessful group (12\u0026thinsp;\u0026plusmn;\u0026thinsp;3 days); however, this difference was not statistically significant. The mean pre-procedure CSRT also showed no difference between the successful group and unsuccessful group. Both mean pre-procedure MD and mean pre-procedure BD values were significantly lower in the successful group (276.13\u0026thinsp;\u0026plusmn;\u0026thinsp;89.59\u0026nbsp;\u0026micro;m versus 633.00\u0026thinsp;\u0026plusmn;\u0026thinsp;182.42\u0026nbsp;\u0026micro;m, and 638.20\u0026thinsp;\u0026plusmn;\u0026thinsp;274.34\u0026nbsp;\u0026micro;m versus 831.00\u0026thinsp;\u0026plusmn;\u0026thinsp;113.18\u0026nbsp;\u0026micro;m, respectively). In contrast, the mean pre-procedure MH height was not significantly different between the two groups. A significantly higher mean pre-procedure MHI was observed in the successful group (0.624\u0026thinsp;\u0026plusmn;\u0026thinsp;0.193) than in the unsuccessful group (0.452\u0026thinsp;\u0026plusmn;\u0026thinsp;0.054). The mean pre-procedure HFF was significantly higher in the successful group than in the unsuccessful group (0.881\u0026thinsp;\u0026plusmn;\u0026thinsp;0.204 versus 0.511\u0026thinsp;\u0026plusmn;\u0026thinsp;0.140). The mean baseline DHI was significantly lower in the successful group (0.474\u0026thinsp;\u0026plusmn;\u0026thinsp;0.161) than in the unsuccessful group (0.751\u0026thinsp;\u0026plusmn;\u0026thinsp;159), whereas the mean baseline THI was significantly higher in the successful group than in the unsuccessful group (1.419\u0026thinsp;\u0026plusmn;\u0026thinsp;0.561 versus 0.640\u0026thinsp;\u0026plusmn;\u0026thinsp;0.245). Moreover, the mean baseline MHV was significantly lower in the successful group than in the unsuccessful group (0.411\u0026thinsp;\u0026plusmn;\u0026thinsp;0.334 versus 1.032\u0026thinsp;\u0026plusmn;\u0026thinsp;0.426). The type of procedure gas (SF\u003csub\u003e6\u003c/sub\u003e) did not differ between the two groups.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003ctable id=\"Tab2\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eComparison of pre-procedure clinical characteristics between the successful and unsuccessful groups of patients with unclosed macular hole treated with fluid-gas exchange.\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eParameters\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eSuccessful group\u003c/p\u003e\n\u003cp\u003e(n\u0026thinsp;=\u0026thinsp;15)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eUnsuccessful group\u003c/p\u003e\n\u003cp\u003e(n\u0026thinsp;=\u0026thinsp;4)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003ep\u003c/em\u003e value\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eInterval between primary surgery and fluid-gas exchange, days, mean (SD)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e17 (8)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e12 (3)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.357\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePre-procedure central subfield retinal thickness, \u0026micro;m, mean (SD)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e307.00 (31.90)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e306.25 (18.84)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.885\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePre-procedure minimum diameter, \u0026micro;m, mean (SD)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e276.13 (89.59)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e633.00 (182.42)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.001\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePre-procedure base diameter, \u0026micro;m, mean (SD)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e638.20 (274.34)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e831.00 (113.18)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.049\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePre-procedure height, \u0026micro;m, mean (SD)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e364.00 (105.81)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e371.75 (18.63)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.810\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePre-procedure macular hole index, mean (SD)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.624 (0.193)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.452 (0.054)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.037\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePre-procedure hole form factor, mean (SD)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.881 (0.204)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.511 (0.140)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.004\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePre-procedure diameter hole index, mean (SD)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.474 (0.161)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.751 (0.159)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.006\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePre-procedure tractional hole index, mean (SD)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1.419 (0.561)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.640 (0.245)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.006\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePre-procedure macular hole volume, mm\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e, mean (SD)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.411 (0.334)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1.032 (0.426)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.014\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eType of procedure gas, SF\u003csub\u003e6\u003c/sub\u003e, n (%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e4 (26.7%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1 (25.0%)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e1.000\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003ctfoot\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"4\"\u003e\u003csup\u003e*\u003c/sup\u003eStatistically significant as calculated using the Mann-Whitney U test.\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"4\"\u003e\u003cem\u003eSD\u003c/em\u003e, standard deviation.\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tfoot\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003ch2\u003eVisual prognosis of the successful and unsuccessful groups\u003c/h2\u003e\n\u003cp\u003eThe successful group presented significantly better final BCVA values (0.33\u0026thinsp;\u0026plusmn;\u0026thinsp;0.18 logMAR) than the unsuccessful group (0.78\u0026thinsp;\u0026plusmn;\u0026thinsp;0.15 logMAR, Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e). Furthermore, the final BCVA in the successful group was significantly improved compared to baseline BCVA (0.85\u0026thinsp;\u0026plusmn;\u0026thinsp;0.22 logMAR), whereas the unsuccessful group demonstrated a poorer final BCVA compared to baseline (0.70\u0026thinsp;\u0026plusmn;\u0026thinsp;0.14 logMAR); however, this difference was not statistically significant (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003ctable id=\"Tab3\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eComparison of baseline and final best-corrected visual acuity between the successful and unsuccessful groups of patients with unclosed macular hole treated with fluid-gas exchange.\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eParameters\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eBaseline\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eFinal\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003ep\u003c/em\u003e value\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBest-corrected visual acuity in the successful group, logMAR, mean \u0026plusmn; (SD)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.85 (0.22)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.33 (0.18)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.001\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eBest-corrected visual acuity in the unsuccessful group, logMAR, mean \u0026plusmn; (SD)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.70 (0.14)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.78 (0.15)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.083\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003ep\u003c/em\u003e value\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.185\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e0.001\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003ctfoot\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"4\"\u003e\u003csup\u003e*\u003c/sup\u003eStatistically significant as calculated using the Mann-Whitney U test or Wilcoxon signed-rank test.\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"4\"\u003e\u003cem\u003eSD\u003c/em\u003e, standard deviation.\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tfoot\u003e\n\u003c/table\u003e\n\u003c/div\u003e"},{"header":"Discussion","content":" \u003cp\u003eThis study retrospectively analysed the baseline and pre-procedure characteristics of patients with primary unclosed MH treated with fluid-gas exchange and showed that several baseline and pre-procedure OCT parameters were associated with the success of the fluid-gas exchange procedure after a failed primary IMH surgery. Various studies have reported relationships between preoperative OCT parameters and the prognosis of MH patients. Shpak \u003cem\u003eet al\u003c/em\u003e.\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e demonstrated that a higher preoperative CSRT is related to the anatomical success of surgical IMH treatment. Similarly, our study showed increased baseline and pre-procedure CSRT values in the successful group compared to those in the unsuccessful group, although this difference was not statistically significant. Wakely \u003cem\u003eet al\u003c/em\u003e.\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e reported that the parameters BD, MH inner opening, and MD were related to the anatomical and functional success in MH surgery. In patients with primary unclosed IMH treated with fluid-gas exchange, a smaller baseline MD, pre-procedure MD, and pre-procedure BD were also related to success. Kusuhara \u003cem\u003eet al\u003c/em\u003e.\u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e showed that IMH patients with MHI values\u0026thinsp;\u0026ge;\u0026thinsp;0.5 had a better postoperative BCVA than those with MHI values\u0026thinsp;\u0026lt;\u0026thinsp;0.5. In this study, baseline and pre-procedure MHI values\u0026thinsp;\u0026ge;\u0026thinsp;0.5 were observed in the successful group with a better final BCVA than those in the unsuccessful group (baseline and pre-procedure MHI\u0026thinsp;\u0026lt;\u0026thinsp;0.5). Several studies have reported that a higher HFF increases the closure rate and improves the postoperative visual outcome in MH patients\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e. In agreement with this publication, significantly higher baseline and pre-procedure HFF values with better final BCVA were observed in the successful group of our study. Ruiz-Moreno \u003cem\u003eet al\u003c/em\u003e.\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e and Dai \u003cem\u003eet al\u003c/em\u003e.\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e demonstrated that a higher THI is correlated with good visual prognosis, whereas DHI is not. However, our study revealed that both higher THI and lower DHI were related to the success of the fluid-gas exchange in patients with primary unclosed MH. Unsal \u003cem\u003eet al\u003c/em\u003e.\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e reported that a higher MHV is associated with a poorer postoperative BCVA, whereas Ozturk \u003cem\u003eet al\u003c/em\u003e.\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e detected no significant correlation. In this study, no difference in baseline MHV was noted between the two groups, but a significantly higher pre-procedure MHV was observed in the unsuccessful group. These findings suggest that MH indicators that are related to the success of primary surgery tend to be also correlated with the success of fluid-gas exchange in patients with failed primary MH treatment. Zou \u003cem\u003eet al\u003c/em\u003e.\u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e reported that a shorter symptom duration is associated with an earlier reconstruction of the external limiting membrane, resulting in better visual outcomes. Shorter symptom duration was also observed in the successful group of our study; however, compared with the unsuccessful group, the difference was not statistically significant.\u003c/p\u003e \u003cp\u003eThe current consensus recommends internal limiting membrane peeling during a MH surgery; however, the face-down position after primary vitrectomy remains controversial\u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e. Nonetheless, a previous meta-analysis concluded that the face-down position is highly recommended when the MH size exceeds 400 \u0026micro;m\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e. In this study, the MH size in all patients at baseline was \u0026gt;\u0026thinsp;400\u0026nbsp;\u0026micro;m, and all patients were positioned face-down after the primary vitrectomy. Among them, 94.74% (18 of 19 patients) had MH closure after the fluid-gas exchange procedure, with \u0026ge;\u0026thinsp;7 days of additional period in face-down position. These findings highlight that an inadequate period of gas tamponade with face-down position might be associated with the failure of primary surgery in IMH patients, and the fluid-gas exchange procedure with the additional period in face-down position is useful in these failed primary IMH patients. One previous study mentioned that SF\u003csub\u003e6\u003c/sub\u003e and C\u003csub\u003e3\u003c/sub\u003eF\u003csub\u003e8\u003c/sub\u003e gas tamponades during surgery show similar MH closure rates\u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e. In agreement with these findings, we observed that the type of gas used for the fluid-gas exchange was not different between the successful and unsuccessful groups.\u003c/p\u003e \u003cp\u003eThis study has some limitations. First, the retrospective design may have resulted in a patient selection bias. Second, this study included only a small number of patients. Therefore, further studies with larger numbers of patients with failed primary IMH treatment will be needed. Despite these limitations, to the best of our knowledge, this is the first study to evaluate the factors associated with the success in patients with failed primary IMH surgery treated with fluid-gas exchange.\u003c/p\u003e \u003cp\u003eIn conclusion, lower pre-procedure BD, lower baseline and pre-procedure DHI and MD, and higher baseline and pre-procedure MHI, HF, and THI values are associated with the success of fluid-gas exchange in patients with failed primary IMH treatment. These results suggest that indices predicting the success of primary IMH surgery may also be useful to predict the success of fluid-gas exchange in patients with failed primary surgery.\u003c/p\u003e "},{"header":"Methods","content":"\u003ch2\u003eStudy design and subjects\u003c/h2\u003e\n\u003cp\u003eThis study was designed as a retrospective, comparative case series conducted in a single hospital. The study adhered to the tenets of the Declaration of Helsinki and was approved by the institutional review board of Keimyung University Dongsan Hospital (IRB no. 2020-12-069). The patients signed informed consent for the use of their data. We retrospectively reviewed the electronic medical records of patients with a history of a failed primary IMH surgery who were treated with fluid-gas exchange between January 2013 and December 2019. The patients with at least 6 months of follow-up period after the procedure were enrolled in the study. The exclusion criteria were as follows: myopia\u0026thinsp;\u0026gt;\u0026thinsp;6 dioptres, presence of rhegmatogenous retinal detachment, diabetic retinopathy, age-related macular degeneration, or a history of previous vitrectomy due to causes other than IMH.\u003c/p\u003e\n\u003cp\u003eAll patients had a full-thickness IMH and underwent primary vitrectomy with internal limiting membrane peeling using the inverted flap technique. Cataract surgery was performed simultaneously when the cataract impaired posterior visualisation. The patients were instructed to remain in a face-down position for \u0026ge;\u0026thinsp;7 days. The fluid-gas exchange procedure was performed on 19 eyes in which an unclosed MH was noted in the spectral-domain OCT (Spectralis OCT/SLO; Ophthalmic Technologies, Toronto, Ontario, Canada) or swept-source OCT (DRI OCT-1; Topcon, Tokyo, Japan) during the follow-up period. The procedure was based on a previous report by Jang \u003cem\u003eet al\u003c/em\u003e.\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e, and the patients were instructed to stay in the face-down position for 7 days. The type and percentage of gas used in the primary surgery were determined by the surgeon\u0026rsquo;s preference. During the fluid-gas exchange, 16% of SF\u003csub\u003e6\u003c/sub\u003e gas or 14% of C\u003csub\u003e3\u003c/sub\u003eF\u003csub\u003e8\u003c/sub\u003e gas was used. All aforementioned surgical and other procedures were performed by a single clinician (Y.C.K.).\u003c/p\u003e\n\u003cp\u003eBased on the classification by Imai \u003cem\u003eet al.\u003c/em\u003e\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e, the outcomes of the fluid-gas exchange procedure were classified as U-type closure, V-type closure, W-type closure, or unclosed. The patients were divided into the successful and unsuccessful groups according to the absence or presence of bare retinal pigment epithelium after the fluid-gas exchange procedure, respectively (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e). Demographic and clinical characteristics were compared between the two groups to assess the prognostic factors.\u003c/p\u003e\n\u003ch2\u003eClinical data collection\u003c/h2\u003e\n\u003cp\u003eThe demographic characteristics including age, sex, and laterality were assessed in all patients. Furthermore, the duration of decreased visual acuity, baseline IOP measured by a non-contact tonometer (Canon TX-20, Canon Inc, Kanagawa, Japan), spherical equivalent, lens status (phakic or pseudophakic), axial length, type of primary surgery (vitrectomy alone or combined cataract surgery) with the type of gas and the percentage used for tamponade during primary surgery, interval period between the primary surgery and fluid-gas exchange, and the type and percentage of gas used in the fluid-gas exchange were recorded. The baseline and final logMAR BCVA values were also assessed. OCT images of all patients were recorded at baseline, pre-procedure, and post-procedure until the last follow-up. CSRT, BD, MD, MH height, MHV height, left arm length, and right arm length were measured using the OCT software measuring tool at baseline and pre-procedure. In addition, the MHI based on the publication by Kusuhara \u003cem\u003eet al\u003c/em\u003e.\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e, the THI and DHI by Ruiz-Moreno \u003cem\u003eet al\u003c/em\u003e.\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e, the HFF by Ullrich \u003cem\u003eet al\u003c/em\u003e.\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e, and the MHV by Ozturk \u003cem\u003eet al\u003c/em\u003e.\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e were calculated.\u003c/p\u003e\n\u003ch2\u003eStatistical methods\u003c/h2\u003e\n\u003cp\u003eData were calculated as the mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation (SD) or n (%; e.g., number of eyes). Statistical analyses were performed using Statistical Package for the Social Sciences version 12.0 (IBM, Chicago, IL, USA). Between-group differences in age, symptom duration, total follow-up period, baseline and final BCVA, baseline IOP, baseline spherical equivalent, percentages of gas tamponade used in primary surgery and fluid-gas exchange, baseline axial length, and baseline and pre-procedure values of BD, MD, MH height, MHI, HFF, DHI, THI, and MHV were compared using the Mann-Whitney U test. Categorical variables, such as sex, affected eye, lens status, type of surgery, and type of gas used in the primary surgery and fluid-gas exchange were compared using the chi-square test or Fisher\u0026rsquo;s exact test. The comparison of baseline and post-procedure BCVA between the two groups was performed using the Wilcoxon signed-rank test. All the tests had two-tailored critical regions for a significance level of 0.05.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eData availability\u003c/h2\u003e\n\u003cp\u003eThe datasets generated and/or analysed during the present study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003ch2\u003eAcknowledgements\u003c/h2\u003e\n\u003cp\u003eThis research was supported by the Bisa Research Grant of Keimyung University in 2020. The sponsor had no role in the design or conduct of this research.\u0026nbsp;\u003c/p\u003e\n\u003ch2\u003eAuthor contributions\u003c/h2\u003e\n\u003cp\u003eY.H.L. conceived and designed the study and wrote the manuscript. S.J.L. was responsible for data curation. J.H.J. reviewed the manuscript. Y.C.K. initiated and supervised the project and reviewed the manuscript. All authors read and approved the final manuscript.\u0026nbsp;\u003c/p\u003e\n\u003ch2\u003eCompeting interests\u003c/h2\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eKelly, N. E. \u0026amp; Wendel, R. T. Vitreous surgery for idiopathic macular holes. Results of a pilot study. \u003cem\u003eArch. Ophthalmol.\u003c/em\u003e \u003cstrong\u003e109,\u003c/strong\u003e 654\u0026ndash;659 (1991).\u003c/li\u003e\n\u003cli\u003eSmiddy, W. E., Feuer, W. \u0026amp; Cordahi, G. Internal limiting membrane peeling in macular hole surgery. \u003cem\u003eOphthalmology\u003c/em\u003e \u003cstrong\u003e108,\u003c/strong\u003e 1471\u0026ndash;1476 (2001).\u003c/li\u003e\n\u003cli\u003eBrooks, H. L., Jr. Macular hole surgery with and without internal limiting membrane peeling. \u003cem\u003eOphthalmology\u003c/em\u003e \u003cstrong\u003e107,\u003c/strong\u003e 1939\u0026ndash;1948 (2000).\u003c/li\u003e\n\u003cli\u003eUllrich, S. \u003cem\u003eet al.\u003c/em\u003e Macular hole size as a prognostic factor in macular hole surgery. \u003cem\u003eBr. J. Ophthalmol. \u003c/em\u003e\u003cstrong\u003e86,\u003c/strong\u003e 390\u0026ndash;393 (2002).\u003c/li\u003e\n\u003cli\u003eUnsal, E., Cubuk, M. O. \u0026amp; Ciftci, F. Preoperative prognostic factors for macular hole surgery: Which is better? \u003cem\u003eOman J. Ophthalmol.\u003c/em\u003e \u003cstrong\u003e12,\u003c/strong\u003e 20\u0026ndash;24 (2019).\u003c/li\u003e\n\u003cli\u003eImai, M., Gotoh, T. \u0026amp; Iijima, H. Additional intravitreal gas injection in the early postoperative period for an unclosed macular hole treated with internal limiting membrane peeling. \u003cem\u003eRetina \u003c/em\u003e\u003cstrong\u003e25,\u003c/strong\u003e 158\u0026ndash;161 (2005).\u003c/li\u003e\n\u003cli\u003eOhana, E. \u0026amp; Blumenkranz, M. S. Treatment of reopened macular hole after vitrectomy by laser and outpatient fluid-gas exchange. \u003cem\u003eOphthalmology\u003c/em\u003e \u003cstrong\u003e105,\u003c/strong\u003e 1398\u0026ndash;1403 (1998).\u003c/li\u003e\n\u003cli\u003eIwase, T. \u0026amp; Sugiyama, K. Additional gas injection after failed macular hole surgery with internal limiting membrane peeling. \u003cem\u003eClin. Exp. Ophthalmol.\u003c/em\u003e \u003cstrong\u003e35,\u003c/strong\u003e 214\u0026ndash;219 (2007).\u003c/li\u003e\n\u003cli\u003eImai, M., Iijima, H., Gotoh, T. \u0026amp; Tsukahara, S. Optical coherence tomography of successfully repaired idiopathic macular holes. \u003cem\u003eAm. J. Ophthalmol.\u003c/em\u003e \u003cstrong\u003e128,\u003c/strong\u003e 621\u0026ndash;627 (1999).\u003c/li\u003e\n\u003cli\u003eShpak, A. A., Shkvorchenko, D. O., Sharafetdinov, I. K. \u0026amp; Yukhanova, O. A. Predicting anatomical results of surgical treatment of idiopathic macular hole. \u003cem\u003eInt. J. Ophthalmol.\u003c/em\u003e \u003cstrong\u003e9,\u003c/strong\u003e 253\u0026ndash;257 (2016).\u003c/li\u003e\n\u003cli\u003eWakely, L., Rahman, R. \u0026amp; Stephenson, J. A comparison of several methods of macular hole measurement using optical coherence tomography, and their value in predicting anatomical and visual outcomes. \u003cem\u003eBr. J. Ophthalmol.\u003c/em\u003e \u003cstrong\u003e96,\u003c/strong\u003e 1003\u0026ndash;1007 (2012).\u003c/li\u003e\n\u003cli\u003eKusuhara, S. \u003cem\u003eet al.\u003c/em\u003e Prediction of postoperative visual outcome based on hole configuration by optical coherence tomography in eyes with idiopathic macular holes. \u003cem\u003eAm. J. Ophthalmol.\u003c/em\u003e \u003cstrong\u003e138,\u003c/strong\u003e 709\u0026ndash;716 (2004).\u003c/li\u003e\n\u003cli\u003eRuiz-Moreno, J. M. \u003cem\u003eet al.\u003c/em\u003e Optical coherence tomography predictive factors for macular hole surgery outcome. \u003cem\u003eBr. J. Ophthalmol.\u003c/em\u003e \u003cstrong\u003e92,\u003c/strong\u003e 640\u0026ndash;644 (2008).\u003c/li\u003e\n\u003cli\u003eDai, Y. M., Shen, J., Li, J. K., Jin, X. H. \u0026amp; Li, Y. M. [Optical coherence tomography predictive factors for idiopathic macular hole surgery outcome]. [Zhonghua yan ke za zhi] \u003cem\u003eChin. J. Ophthalmol.\u003c/em\u003e \u003cstrong\u003e49,\u003c/strong\u003e 807\u0026ndash;811 (2013).\u003c/li\u003e\n\u003cli\u003eOzturk, T. \u003cem\u003eet al.\u003c/em\u003e Effect of macular hole volume on postoperative central macular thickness. \u003cem\u003eArq. Bras. Oftalmol.\u003c/em\u003e \u003cstrong\u003e79,\u003c/strong\u003e 137\u0026ndash;142 (2016).\u003c/li\u003e\n\u003cli\u003eZou, J.-L. \u0026amp; Zeng, J. The macular microstructure repair and predictive factors of surgical outcomes after vitrectomy for idiopathic macular hole. \u003cem\u003eInt\u003c/em\u003e\u003cem\u003e.\u003c/em\u003e\u003cem\u003e J\u003c/em\u003e\u003cem\u003e.\u003c/em\u003e\u003cem\u003e Ophthalmol\u003c/em\u003e\u003cem\u003e.\u003c/em\u003e \u003cstrong\u003e12,\u003c/strong\u003e 852\u0026ndash;857 (2019).\u003c/li\u003e\n\u003cli\u003eNadal, J., Delas, B. \u0026amp; Pi\u0026ntilde;ero, A. Vitrectomy without face-down posturing for idiopathic macular holes. \u003cem\u003eRetina\u003c/em\u003e \u003cstrong\u003e32,\u003c/strong\u003e 918\u0026ndash;921 (2012).\u003c/li\u003e\n\u003cli\u003eYe, T. \u003cem\u003eet al.\u003c/em\u003e Macular hole surgery recovery with and without face-down posturing: a meta-analysis of randomized controlled trials. \u003cem\u003eBMC Ophthalmol. \u003c/em\u003e\u003cstrong\u003e19,\u003c/strong\u003e 265 (2019).\u003c/li\u003e\n\u003cli\u003eModi, A., Giridhar, A. \u0026amp; Gopalakrishnan, M. Sulfurhexafluoride (SF\u003csub\u003e6\u003c/sub\u003e) versus perfluoropropane (C\u003csub\u003e3\u003c/sub\u003eF\u003csub\u003e8\u003c/sub\u003e) gas as tamponade in macular hole surgery. \u003cem\u003eRetina \u003c/em\u003e\u003cstrong\u003e37,\u003c/strong\u003e 283\u0026ndash;290 (2017).\u003c/li\u003e\n\u003cli\u003eJang, J. H., Kim, Y. C. \u0026amp; Kim, K. S. The efficacy of fluid-gas exchange for the treatment of postvitrectomy retinal detachment. \u003cem\u003eKorean J. Ophthalmol.\u003c/em\u003e \u003cstrong\u003e23,\u003c/strong\u003e 253\u0026ndash;258 (2009).\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"fluid-gas exchange, idiopathic macular hole (IMH), U-type, V-type, W-type","lastPublishedDoi":"10.21203/rs.3.rs-149595/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-149595/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis retrospective study aimed to evaluate prognostic factors associated with the success of fluid-gas exchange in patients with failed primary idiopathic macular hole (IMH) surgery. Outcomes of the fluid-gas exchange were categorised as unclosed, or U-type, V-type, or W-type closure. Patients were divided into the successful and unsuccessful groups according to the absence or presence of bare retinal pigment epithelium, respectively, following fluid-gas exchange. Demographics, baseline characteristics, and pre-procedure characteristics were assessed. A total of 19 eyes in 19 patients that had failed IMH surgery and then underwent fluid-gas exchange were included. Of those, 18 eyes had MH closure (successful, 15 eyes; unsuccessful, three eyes). One eye was unclosed after fluid-gas exchange; therefore, the patient underwent additional vitrectomy for MH closure (unsuccessful). The successful group showed significantly lower pre-procedure base diameters; higher baseline and pre-procedure macular hole index, hole form factor, and tractional hole index values; and lower baseline and pre-procedure minimum diameter and diameter hole index values. Moreover, a better visual prognosis was observed in the successful group. These results suggest that indices predicting favourable results of primary surgery for IMH are useful to predict the success of fluid-gas exchange in patients with failed primary MH surgery.\u003c/p\u003e","manuscriptTitle":"Prognostic Factors of Fluid-gas Exchange Outcomes in Patients with Failed Primary Surgery for Idiopathic Macular Hole","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2021-01-20 18:00:12","doi":"10.21203/rs.3.rs-149595/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"cb63c4b7-a237-4dc5-8400-2e9e51094684","owner":[],"postedDate":"January 20th, 2021","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":1981581,"name":"Health Economics \u0026 Outcomes Research"},{"id":1981582,"name":"Medical Genetics"},{"id":1981583,"name":"Scientific Communication"}],"tags":[],"updatedAt":"2021-03-02T23:59:05+00:00","versionOfRecord":[],"versionCreatedAt":"2021-01-20 18:00:12","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-149595","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-149595","identity":"rs-149595","version":["v1"]},"buildId":"_2-kVJe1T_tPrBINL-cwx","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}