Five year’s outcomes of Trabeculo-Canalectomy for Chinese PACG Patients: a retrospective study

Five year’s outcomes of Trabeculo-Canalectomy for Chinese PACG Patients: a retrospective study | 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 Five year’s outcomes of Trabeculo-Canalectomy for Chinese PACG Patients: a retrospective study Zhan Xie, Tianhao Xiao, Junlong Huang, Mulong Du, Ping Zhang, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5668721/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 22 Apr, 2025 Read the published version in BMC Ophthalmology → Version 1 posted 8 You are reading this latest preprint version Abstract Background To evaluate the 5-year outcomes of trabeculo-canalectomy in the treatment of primary angle-closure glaucoma (PACG) among Chinese patients. Methods A retrospective study was designed, involving 46 PACG patients (50 eyes) treated with trabeculo-canalectomy at the First Affiliated Hospital of Nanjing Medical University from January 2016 to December 2018. The patients were followed up at 1 week, 1 month, 3 months, 6 months, 12 months, 1 year, 2 years and 5 years. Surgical success was defined as intraocular pressure (IOP) ≤ 21 mmHg (1 mmHg = 0.133 kPa) under glaucoma medication (qualified success) and without any glaucoma medication (absolute success). Main outcomes were measured according to IOP, number of medication regimens, surgical success rate, complications, and filtering bleb status. Results A total of 46 PACG patients (50 eyes) were finally included for statistical analysis, with a mean age of 56.68 ± 6.75 years (range, 41–69 years). The mean preoperative IOP was 30.72 ± 10.26 mmHg with a median number of medication regimens of 2 (range, 0 to 4). Compared to those before the operation, the mean IOP decreased to 12.15 ± 3.11, 14.33 ± 4.10, 15.68 ± 4.24, 16.45 ± 4.14, 16.95 ± 3.51, 17.67 ± 3.15 and 17.04 ± 3.78 mmHg at 1 week, 1 month, 3 months, 6 months, 12 months, 1 year, 2 years and 5 years, respectively. The median (range) numbers of medication regimens were 0 (0 ~ 1), 0 (0 ~ 2), 0 (0 ~ 2), 0 (0 ~ 2), 0 (0 ~ 2), 0 (0 ~ 3), 0 (0 ~ 3), 0 (0 ~ 3) at the eight time points, respectively. The mean postoperative IOP and the number of medication regimens at each time point were significantly lower than those before operation (all P < 0.01). The 5-year total success rate was 89%, and the absolute success rate was 78%. Shallow anterior chamber (10%) and hyphema (12%) were the most common complications early after surgery. At 3 months, anterior segment slit-lamp photography and ultrasound biomicroscopy showed no obvious filtering blebs in 50 eyes (100%). IOP increased transiently in 6 eyes (12%) within 1 month after surgery. Conclusion Simple and cost-saving trabeculo-canalectomy provides favorable 5-year outcomes in the treatment of medically uncontrolled PACG, as shown by more effective IOP control, more obvious drug reduction, as well as fewer post-operative interventions compared to trabeculectomy. Primary angle-closure glaucoma trabeculo-canalectomy Schlemm’s canal 5-year outcome Figures Figure 1 Figure 2 Figure 3 Background Primary angle-closure glaucoma (PACG), a major subtype of glaucoma, accounts for 50% of all glaucoma-related cases of blindness worldwide [ 1 , 2 ]. The number of PACG patients is estimated to reach 32.04 million by 2040 globally, three quarters of which occur in Asia [ 3 , 4 ], indicating that PACG has become a worldwide public health burden [ 5 , 6 ]. Given that PACG arises from anatomical derangement of the anterior segment, all treatment strategies aim at repairing anatomical defects and reducing intraocular pressure (IOP) [ 4 ]. Cataract surgery with or without trabeculectomy (Trab) is advocated as the initial treatment for PACG patients with younger ages, clear lens and diffused peripheral anterior synechiae (> 180 degrees) [ 1 , 7 – 9 ]. However, its efficacy is significantly reduced by excessively low or high filtration that inevitably leads to hypotony, shallow anterior chamber, scars, and other complications [ 10 ]. Therefore, Trab should be modified to improve efficacy and reduce complications in the treatment of glaucoma. Trab was first proposed by Cairns [ 11 ]. In about two-thirds of Cairns’ cases, IOP can be continuously controlled without subconjunctival drainage to aqueous humor [ 12 ]. As suggested by Carins, this surgical technique can reduce IOP in chronic simple glaucoma by relieving trabecular obstruction without intentionally creating external drainage. Cairns lays out a rationale for us to design trabeculo-canalectomy [ 14 ]. In PACG patients, the anterior chamber angle is blocked by anatomical alterations, thus impeding the aqueous humor flowing through [ 9 , 13 ] while the post-trabecular outflow pathway may remain intact [ 9 , 14 , 15 ]. A direct communication between the anterior chamber and the Schlemm’s canal can restore aqueous humor outflow in PACG patients [ 9 ]. Thus, it is theoretically possible to re-establish this communication for reducing IOP independent of a filtration bleb. Herein, we modified Trab into trabeculo-canalectomy, by draining the aqueous humor from the cut end of Schlemm’s canal to re-establish good IOP control, without dependence on a filtration bleb and preventing post-surgery scarring. We evaluated its 5-year clinical outcomes in treating medically uncontrolled PACG eyes. Materials and methods Study population Enrolled were 60 patients (70 eyes) treated with trabeculo-canalectomy in the First Affiliated Hospital of Nanjing Medical University, China, from January 2016 to December 2018. Of them, 14 patients (20 eyes, 28.57%) were excluded due to a follow-up of < 3 months. Finally, 46 patients (50 eyes) were included. Inclusion Criteria Inclusion criteria included Ages 40 years or above; Medically uncontrolled PACG and peripheral anterior synechiae of more than 180°; Uncontrolled PACG defined as IOP > 21 mmHg for at least three consecutive measurements within previous one month, and on two or more glaucoma medications in the presence of glaucomatous optic disc neuropathy and visual field deficiency; Best corrected visual acuity (LogMAR) ≤ 0.3 without obvious lens opacity. Exclusion criteria Exclusion criteria included Primary open angle glaucoma, neovascular glaucoma, normal tension glaucoma, traumatic glaucoma, and secondary glaucoma; Other histories of fundus disease and eye surgery (except for laser periphery iridotomy or iridoplasty); Signs of suprascleral venous hypertension (e.g., torturous and dilated suprascleral veins); Severe heart, lung disease, and advanced cancer; A history of mental illness; Previous treatment with anticoagulant therapy and kidney dialysis or pregnancy; No informed consent; Incapability to adhere to the follow-up schedule required by this study. Surgical Procedures All surgeries were performed by one designated experienced surgeon at the First Affiliated Hospital of Nanjing Medical University. 2.5 mL of 2% lidocaine + 0.75% bupivacaine (mixed in a ratio of 1:1) was applied for peribulbar anesthesia. A suspension wire was made of 8 − 0 absorbable suture in the corneal limbus. A fornix-based incision through the conjunctiva and Tenon's capsule was made. Then, a 4×4 mm superficial scleral flap in 1/2 scleral thickness was sculpted ( Fig. 1 a). Schlemm’s canal was located (Fig. 1 b), its outer wall opened (Fig. 1 c-d), and then this wall and the trabecular meshwork measuring 1×2 mm removed (Fig. 1 e). Following resection of the peripheral iris at 12 o’clock (Fig. 1 f), moderate viscoelastic agents were injected under the scleral flap to reinsert the iris (Fig. 1 g). The scleral flap was closed tightly with two sutures of 10 − 0 nylon (Fig. 1 h). The conjunctiva-Tenon's layer was sutured with 10 − 0 nylon at the ends of the incision (Fig. 1 i). The corneal side port incisions were hydrated and made watertight. Antimetabolic agents such as mitomycin C or 5- fluorouracil were not used intraoperatively. Observational Indexes Postoperative follow-up was made at 1 week, 1 month, 3 months, 6 months, 12 months, 1 year, 2 years and 5 years, with additional visits whenever necessary, for documentation of IOP, number of anti-glaucoma regimens, best corrected visual acuity (BCVA), results of anterior and posterior segment examination, frequency of complications, postoperative interventions and morphology of filtering blebs. Evaluation of Surgical Success or Failure Evaluation of surgical success or failure included[ 16 ] (1) Complete success: post-operative IOP at 6 to 21 mmHg without anti-glaucoma medications; (2) Conditional success: post-operative IOP at 6 to 21 mmHg with local application of anti-glaucoma medications; (3) Failure: post-operative IOP lower than 6 mmHg or higher than 21 mmHg after application of anti-glaucoma medications. In these cases, severe complications were observed, such as retinal detachment and endophthalmitis. The extent and height of filtering blebs were graded by Indiana Bleb Appearance Grading Scale (IBAGS) [ 17 ]. Bleb height referred to the vertical dimension of the filtering bleb and represented the elevation of the conjunctival flap above the scleral surface. The height of the bleb was divided into four levels: H0, flat without visible elevation; H1, slight elevation; H2, moderate elevation; and H3, significant elevation as compared with the standard images. Bleb extent represented the horizontal dimension of the filtering bleb, or bleb area. This extent was also divided into four levels: E0, no visible extent (within less than 1 clock); E1, extent between 1 clock and 2 clock hours; E2, extent between 2 clock and 4 clock hours; and E3, extent beyond 4 clock hours. Statistical analysis SPSS version 21.0 was used for statistical analyses. Continuous variables were summarized as means, standard deviations, medians, and ranges; categorical variables as frequencies and percentages. Student’s t test was performed for comparison between groups, and one-way ANOVA for comparison among three or more groups. Statistical significance was defined by a P value < 0.05. Results A total of 46 PACG patients (50 eyes), including 17 men, were recruited in this study, with a mean age of 56.68 ± 6.75 years (range 41–69 years), an average preoperative IOP of 30.72 ± 10.26 mmHg, and a median (range) number of medication regimens of 2 (0 ~ 4). Patient characteristics are presented in Table 1 . Table 1 The basic data for patient enrollments. Characteristics Values No. of eyes/patients 50/46 OD/OS 19/31 Gender (male/female) 17/33 Age 56.68 ± 6.75 Preoperative IOP (mmHg) 30.72 ± 10.26 Preoperative medications 2.26 ± 0.83 Preoperative BCVA (LogMAR) 0.21 ± 0.08 History of LPI (n, %) 26(52%) phakic eye (n, %) 50(100%) Data were expressed as mean ± SD. BCVA = best-corrected visual acuity, IOP = intraocular pressure, LPI = laser peripheral iridotomy, SD = standard deviation. The mean postoperative IOP decreased from the preoperative 30.72 ± 10.26 to 12.15 ± 3.11, 14.33 ± 4.10, 15.68 ± 4.24, 16.45 ± 4.14, 16.95 ± 3.51, 17.67 ± 3.15 and 17.04 ± 3.78 mmHg at 1 week, 1 month, 3 months, 6 months, 1 year, 2 years and 5 years, respectively (Table 2 ). The difference between the mean IOP values at baseline and each follow-up point was statistically significant ( P < 0.001, Fig. 2 ). The median (range) numbers of medication regimens were 0 (0 ~ 1), 0 (0 ~ 2), 0 (0 ~ 2), 0 (0 ~ 2), 0 (0 ~ 2), 0 (0 ~ 3), 0 (0 ~ 3) at the seven time points, respectively (Table 2 ). The difference between the numbers of anti-glaucoma regimens at baseline and each follow-up point was statistically significant ( P < 0.001, Table 2 ). BCVA at post-operative 5 years was 0.23 ± 0.11, and not different from that at baseline ( P = 0.388). Table 2 IOP and medications of the patients completed trabeculo-canalectomy. Follow-up time N IOP (mmHg) Eyes with meds/tota(%) Number of meds regimens Pre-operation 50 30.72 ± 10.26 50(100) 2.26 ± 0.83 1 wk 50 12.15 ± 3.11 1(2) 0.02 ± 0.14 1 mo 50 14.33 ± 4.10 6(12) 0.10 ± 0.36 3 mo 50 15.68 ± 4.24 7(14) 0.18 ± 0.48 6 mo 50 16.45 ± 4.14 13(26) 0.34 ± 0.63 1 y 50 16.95 ± 3.51 15(30) 0.42 ± 0.73 2 y 41 17.67 ± 3.15 14(34.1) 0.54 ± 0.84 5 y 36 17.04 ± 3.78 13(36.1) 0.58 ± 0.91 P -value < 0.001 * < 0.001 † Data were expressed as mean ± SD. IOP = intraocular pressure, SD = standard deviation, meds = medications. *One-way repeated measure ANOVA analysis. † Chi-square analysis. The total success rate of surgery was 89% at 5 years, including the complete success rate 78% and the conditional success rate 11% (Table 3 ). According to IBAGS, the filtering bleb in 5 (10%) eyes was graded as E1H1 at 1 week after surgery. Ultrasound biomicroscopy and anterior segment slit-lamp photography showed that 50 eyes (100%) had no obvious filtering bleb (E0H0) at 3 months (Fig. 3 ). Shallow anterior chamber (10%) and hyphema (12%) were the most common complications early after surgery. IOP elevated in 6 eyes (12%) transiently within 1 month after surgery, and was reduced after topical use of glaucoma medications. No blebitis, hypotony, choroidal detachment, malignant glaucoma and endophthalmitis were observed. Table 3 Rates of absolute and qualified successes. Follow-up time 1 wk 1 mo 3 mo 6 mo 1 y 2 y 5 y SUM 50 50 50 50 50 41 36 Total success, N (%) 50(100%) 47(94%) 48(96%) 45(90%) 46(92%) 37(90%) 32(89%) Absolute success, N (%) 50(100%) 44(88%) 42(84%) 36(72%) 35(70%) 27(66%) 22(78%) Qualified success, N (%) 0 3(6%) 6(12%) 9(18%) 11(22%) 10(24%) 10(11%) SUM: summary; N: number. Discussion Trab is the primary approach to treat glaucoma; however, vision-threatening complications may occur in 39% of Trab-treated cases, 74% of which need urgent postoperative interventions [ 18 ]. Moreover, bleb-related complications may persist, regardless of IOP well controlled after surgery [ 19 ]. Additionally, scarring in the filtering bleb often leads to treatment failure [ 17 ]. Thus, anti-scarring and bleb-independent surgical procedures remain to be developed. In the present study, we reported the 5-year outcomes of bleb-independent trabeculo-canalectomy, a novel procedure. At five years, trabeculo-canalectomy achieved a total success rate of 89% (Table 3 ), suggesting its superior therapeutic effects in comparison with previous literatures [ 20 – 23 ]. Surgical complications mainly occurred within 1 month after surgery, including shallow anterior chamber (10%), hyphema (12%), and transient IOP elevation (12%). A filtering bleb was not needed after trabeculo-canalectomy. This surgery provides a new option for PACG patients. Trab, initially described by Cairns in 1968 [ 12 ], has been considered as the “gold standard” for filtration surgery [ 24 ]. Initially, this operation aims to remove the Schlemm’s canal and trabecular meshwork and form a natural pathway for aqueous to egress the eye, in addition to bleb formation. But, later histopathologic examinations recognized that what the surgeons mostly remove was not Schlemm’s canal or trabecular meshwork, but the peripheral cornea, and IOP reduction is mainly due to filtering bleb formation. Then, Trab was modified as an “externo technique” by surgeons. Previous studies have shown that the effect of Trab fails in about 30% cases at 3 years, and nearly 50% at 5 years [ 22 , 23 ], mainly due to the formation of scar tissue in the conjunctiva, the tenon capsule and the interocular membrane as the natural reaction to wound healing [ 25 ]. It is worth noting that trabeculo-canalectomy reported in this study might revolutionize the surgical concept of “external filtration” by reconstructing a physiological drainage channel for the treatment of PACG. It proves an “internal filtration” and bleb-independent procedure that prevents the occurrence of filtration bubble scarring. With the excision of a portion of the Schlemm’ Canal with its trabecular covering, two cut ends were left open into aqueous humor, thus restoring the integrity of the corneoscleral coat over the excision (Fig. 1 a-e). These procedures enabled tight suturing of the conjunctival flap and scleral flap (Fig. 1 h-i), absence of filtering blebs (Fig. 3 ), and well controlled IOP (Fig. 2 ). Trabeculo-canalectomy, which is bleb-independent, significantly reduces the incidence of filtering bleb- and antimetabolite-related complications, which are frequent in trabeculectomy [ 10 , 26 – 28 ]. Additionally, post-operative interventions of filtering blebs [ 29 ], such as releasable sutures and bleb needling, were not necessarily performed in our research. Third, tight suturing of the conjunctival flap and scleral flap significantly reduces complications early after surgery [ 30 ], such as hypotony and shallow anterior chamber related to over-filtration. Hypotony occurs in 10–37.5% cases after traditional Trab [ 9 , 31 ], but none after trabeculo-canalectomy in the present study. In summary, trabeculo-canalectomy facilitates aqueous outflow and restores filtration through Schlemm’s canal, demonstrating long-term efficacy and safety for PACG patients. Designed according to a concept of “internal drainage” (similar to ours), penetrating Schlemm canaloplasty has been first composed by Professor Liang in 2015, and also achieved remarkable clinical success [ 9 , 32 – 35 ]. In this surgery, a direct communication is established between the anterior chamber and the Schlemm’s canal to restore aqueous humor outflow in PACG patients, thus combining the advantages of suture tensioning canaloplasty with Trab. The success rate of this surgery can reach 86.8% in PACG patients [ 9 , 34 ]. However, in Liang’s surgery, Schlemm’s canal needs to be perforated by microcatheter throughout the operation, and tensioning suture serves to keep Schlemm’s canal patent [ 9 , 35 ]. As a consequence, this surgery procedure is relatively complex for clinicians, and their long learning curve may also lead to clinical failure in some cases. Additionally, the microcatheter used during the procedure is expensive [ 36 ]. In comparison, our trabeculo-canalectomy is relatively simple and cost-saving, mainly including the following steps: a superficial scleral flap, 4×4 mm and 1/2 scleral thickness, was forwarded into the clear corneal limbus by about 1mm. Then, the clear corneal area and the white sclera area were identified. The gray zone, also known as the grayish blue trabecular meshwork, was delineated. The Schlemm’s canal runs at the junction between the grayish blue trabecular meshwork and the white sclera, and the Schlemm tube was accurately located at the posterior 1/2 of the gray area (Fig. 1 b). At this time, the outer wall of the Schlemm’s canal was gently lifted by microscope forceps, and then opened to expose its cavity more easily (Fig. 1 b-c). Before opening the Schlemm’s canal, anterior chamber paracentesis was performed to prevent the iris from excessively prolapsing to the incision site. Since the Schlemm’s canal is close to the root of the iris, it is recommended to clip the iris slightly away from the Schlemm’s canal and perform iridectomy to reduce iris bleeding (Fig. 1 f). The scleral and conjunctival flaps were tightly sutured with 10 − 0 nylon suture to avoid early filtration (Fig. 1 h-i). Notably, though simple and cost-saving trabeculo-canalectomy provides favorable 5-year outcomes in the treatment of PACG, the procedure may not achieve similar efficacy in patients with certain types of glaucoma, the pathophysiology of which may lie beyond the Schlemm’s canal, such as primary open-angle glaucoma (POAG). The developmental abnormalities in the outflow routes and collapse of Schlemm lumen have been reported in POAG patients [ 37 ]. The cutting ends of Schlemm’s canal may be more prone to the occurrence of adhesion and closure in POAG patients. In addition, our previous research shows that patients with secondary glaucoma, especially uveitic glaucoma, were more likely to undergo surgical failure[ 16 ]. Adequate anti-inflammatory therapy combined with antimetabolic drugs is often needed in the surgical treatment of uveitic glaucoma. There are some limitations in this study. First of all, only PACG patients in China were included, and our surgery may not be suitable to PACG patients in other countries. Part of the patients included were binocular, and the statistical results may have been biased. Second, the sample size of this study was small. In addition, aqueous oozing from the Decemet’s membrane and trabecular meshwork is a marker for the positioning of the canal of Schlemm. However, due to the extensive peripheral anterior synechiae and obstruction of the trabecular meshwork, aqueous oozing is infrequent in PACG eyes, thus challenging the recognition of the Schlemm’s canal in PACG patients. This requires a learning curve for a surgeon. More randomized controlled trials should be conducted in the near future to directly compare the efficacy, safety and cost-effectiveness of this procedure with Trab. Conclusion Tabeculo-canalectomy provides favorable 5-year outcomes in treating medically uncontrolled PACG, as shown by effective IOP control, obvious drug reduction, as well as less post-operative interventions compared to Trab. Abbreviations PACG Primary angle-closure glaucoma POAG Primary angle-open glaucoma IOP Intraocular pressure Trab Trabeculectomy IBAGS Indiana Bleb Appearance Grading Scale BCVA Best-corrected visual acuity LPI Laser peripheral iridotomy SD Standard deviation Meds Medications SUM Summary N Number Declarations Acknowledgements We would like to thank Yong-ke Cao for proofreading of the manuscript. Authors’ contribution ZX, THX, PX and HS designed the research project; ZX, THX, JLH, and PZ performed the research; ZX and MLD analyzed the data; ZX wrote the manuscript draft; MLD, YTZ, PX and HS revised the manuscript. Funding This study was supported by a grant from the National Natural Science Foundation of China (Grant Number: 82401281). Ethics approval and consent to participate This was a retrospective study approved by the First Affiliated Hospital of Nanjing Medical University (No.2023-SR-474), abiding by the Declaration of Helsinki . Written consent was obtained from all patients before surgery. Consent for publication Not applicable. Competing interests The authors declare that they have no competing interests. References Song Y, Zhang H, Zhang Y, Tang G, Wan KH, Lee JWY, Congdon N, Zhang M, He M, Tham CC et al : Minimally Invasive Glaucoma Surgery in Primary Angle-Closure Glaucoma . Asia Pac J Ophthalmol (Phila) 2022, 11 (5):460-469. Song Y, Lin F, Lv A, Zhang Y, Lu L, Xie L, Tang G, Yuan H, Yang Y, Xu J et al : Phacogoniotomy versus phacotrabeculectomy for advanced primary angle-closure glaucoma with cataract: A randomized non-inferiority trial . Asia Pac J Ophthalmol (Phila) 2024, 13 (1):100033. 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Ye W, Li J, Zhang S, Zhu S, Xie Y, Le R, Zhou W, He M, Wang N, Liang Y: Efficacy and safety of penetrating canaloplasty versus ab externo canaloplasty for primary open-angle glaucoma: A randomized controlled trial . Acta Ophthalmol 2024. Xu SX, Ye WQ, Zhang JT, Li JX, Xie YQ, Zhang SD, Li GX, Liang YB: [Clinical characteristics and surgical management outcomes of glaucoma secondary to congenital ectropion uveae: a preliminary analysis of penetrating Schlemm's canaloplasty] . Zhonghua Yan Ke Za Zhi 2024, 60 (5):416-422. Hu JJ, Lin HS, Zhang SD, Ye WQ, Gu J, Xie YQ, Tang YH, Liang YB: A new bleb-independent surgery namely penetrating canaloplasty for corticosteroid-induced glaucoma: a prospective case series . Int J Ophthalmol 2022, 15 (7):1077-1081. Cheng HH, Hu C, Meng JY, Zhang SD, Lin SG, Bao JY, Xie YQ, Le RR, Ye C, Liang YB: [Preliminary efficacy of penetrating canaloplasty in primary angle-closure glaucoma] . Zhonghua Yan Ke Za Zhi 2019, 55 (6):448-453. Liang Y, Yu Q, Sun H, Sucijanti, Gu L, Yuan Z: Modified suture-assisted canaloplasty in Asians with primary open-angle glaucoma: a prospective study with 12-month follow-up . BMC Ophthalmol 2022, 22 (1):202. Hamanaka T, Sakurai T, Fuse N, Ishida N, Kumasaka T, Tanito M: Comparisons of Schlemm's canal and trabecular meshwork morphologies between juvenile and primary open angle glaucoma . Exp Eye Res 2021, 210 :108711. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 22 Apr, 2025 Read the published version in BMC Ophthalmology → Version 1 posted Editorial decision: Accepted 08 Apr, 2025 Reviews received at journal 08 Apr, 2025 Reviewers agreed at journal 07 Apr, 2025 Reviews received at journal 04 Apr, 2025 Reviewers agreed at journal 04 Apr, 2025 Reviewers invited by journal 02 Apr, 2025 Submission checks completed at journal 28 Mar, 2025 First submitted to journal 27 Mar, 2025 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. 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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-5668721","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":437699651,"identity":"81fc532b-de39-4ace-8f0a-24708043eb21","order_by":0,"name":"Zhan Xie","email":"","orcid":"","institution":"the First Affiliated Hospital of Nanjing Medical University","correspondingAuthor":false,"prefix":"","firstName":"Zhan","middleName":"","lastName":"Xie","suffix":""},{"id":437699654,"identity":"770eaed8-adfe-4f03-bc39-4e5c60d47f62","order_by":1,"name":"Tianhao Xiao","email":"","orcid":"","institution":"the First Affiliated Hospital of Nanjing Medical University","correspondingAuthor":false,"prefix":"","firstName":"Tianhao","middleName":"","lastName":"Xiao","suffix":""},{"id":437699658,"identity":"fb116caa-ace5-4440-bc9f-e90666d01c8e","order_by":2,"name":"Junlong Huang","email":"","orcid":"","institution":"the First Affiliated Hospital of Nanjing Medical University","correspondingAuthor":false,"prefix":"","firstName":"Junlong","middleName":"","lastName":"Huang","suffix":""},{"id":437699662,"identity":"eb93a55f-fa61-43f4-a1be-7a7b28fbbf73","order_by":3,"name":"Mulong Du","email":"","orcid":"","institution":"Nanjing Medical University","correspondingAuthor":false,"prefix":"","firstName":"Mulong","middleName":"","lastName":"Du","suffix":""},{"id":437699663,"identity":"9fe66f18-4c59-47c1-b5e3-3022fea34c0c","order_by":4,"name":"Ping Zhang","email":"","orcid":"","institution":"the First Affiliated Hospital of Nanjing Medical University","correspondingAuthor":false,"prefix":"","firstName":"Ping","middleName":"","lastName":"Zhang","suffix":""},{"id":437699665,"identity":"79ee4fda-f869-4922-be16-57eb0f59eef4","order_by":5,"name":"Ying-Ting Zhu","email":"","orcid":"","institution":"R\u0026D Department; Tissue Tech Inc.;Miami, FL USA","correspondingAuthor":false,"prefix":"","firstName":"Ying-Ting","middleName":"","lastName":"Zhu","suffix":""},{"id":437699666,"identity":"7e9b951c-f7b2-44f7-9c2e-d0a1626bfe67","order_by":6,"name":"Ping Xie","email":"","orcid":"","institution":"the First Affiliated Hospital of Nanjing Medical University","correspondingAuthor":false,"prefix":"","firstName":"Ping","middleName":"","lastName":"Xie","suffix":""},{"id":437699667,"identity":"5e6b2d6c-c40a-4260-a565-a3dfeee5d9c2","order_by":7,"name":"Hong Sun","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA0UlEQVRIiWNgGAWjYHACNhAhx8BwAEQzE6/FmHQtiQ0QDhFa5GfkHnvwcUdt+nbG02kSDBXWiQ3sZw/g1WJwIy/dcOaZ47k7G85uk2A4k57YwJOXgF+LRI6ZNG/bsdwNB4BaGNsOJzZI8BgQcBhES7oBWMs/IrQw3ABrqUmAaGkgQovBmTdmkjPbDhgCHbbZIuFYunEbTw4Bh7XnmEl8bKuTN7hxduONDzXWsv3sZwg4DAIOMzBIHGBgSGCARhMRoI6Bgb+BSLWjYBSMglEw4gAABKBIXZx79xkAAAAASUVORK5CYII=","orcid":"","institution":"the First Affiliated Hospital of Nanjing Medical University","correspondingAuthor":true,"prefix":"","firstName":"Hong","middleName":"","lastName":"Sun","suffix":""}],"badges":[],"createdAt":"2024-12-18 10:53:14","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5668721/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5668721/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s12886-025-04051-6","type":"published","date":"2025-04-22T15:57:22+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":79906322,"identity":"029e7b84-345a-4aa9-83af-7f65ab45cdbc","added_by":"auto","created_at":"2025-04-04 11:07:23","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":348920,"visible":true,"origin":"","legend":"\u003cp\u003eTrabeculo-canalectomy procedures. \u003cstrong\u003ea \u003c/strong\u003eDissecting a rectangular superficial scleral flap of 4×4 mm and in 1/2 scleral thickness at the superior limbus into the transparent cornea. \u003cstrong\u003eb \u003c/strong\u003eLocating Schlemm’s canal. Black arrows indicate the broken end of Schlemm’s canal. \u003cstrong\u003ec\u003c/strong\u003eInserting the corneal scissors into the broken end of Schlemm’s canal. \u003cstrong\u003ed\u003c/strong\u003e Opening the outer wall of Schlemm’s canal. Black arrows indicate the unroofed Schlemm’s canal. \u003cstrong\u003ee\u003c/strong\u003e Removing the outer wall of Schlemm’s canal and the juxtacanalicular trabecular meshwork. \u003cstrong\u003ef\u003c/strong\u003ePeripheral iridectomy. \u003cstrong\u003eg\u003c/strong\u003e Injecting moderate viscoelastic agents under the scleral flap to reinsert the iris. \u003cstrong\u003eh\u003c/strong\u003e Closing the scleral flap tightly with two sutures of 10-0 nylon. \u003cstrong\u003ei\u003c/strong\u003e Suturing the conjunctiva-Tenon’s layer with 10-0 nylon at the end of the incision.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-5668721/v1/c2f128344835fd29781c92ae.png"},{"id":79907850,"identity":"78f0c1fc-a5d2-4e08-8f33-398458d0a2c2","added_by":"auto","created_at":"2025-04-04 11:15:23","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":45560,"visible":true,"origin":"","legend":"\u003cp\u003eIntraocular pressure values at baseline and seven follow-up time points. IOP values were shown as mean ± SD. SD, standard deviations. IOP, intraocular pressure.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-5668721/v1/0b47b22c0edb6ce3735efe12.png"},{"id":79905817,"identity":"52c20cbf-dd0a-49a1-8016-5ac1b1376e91","added_by":"auto","created_at":"2025-04-04 10:59:23","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":168811,"visible":true,"origin":"","legend":"\u003cp\u003eSlit-lamp photographs and ultrasound biomicroscopy images in a patient with PACG at 5 years after trabeculo-canalectomy. \u003cstrong\u003ea\u003c/strong\u003e-\u003cstrong\u003eb\u003c/strong\u003e Slit-lamp photographs showing the absence of filtration blebs. \u003cstrong\u003ec\u003c/strong\u003e Ultrasound biomicroscopy images showing no obvious filtration blebs at the operation site. \u003cstrong\u003ed\u003c/strong\u003e Ultrasound biomicroscopy images showing that periphery anterior chamber angle kept closed after the surgery except for the operation site.\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-5668721/v1/e6ff0c155c34b8a1c423ce90.png"},{"id":81569809,"identity":"0a550f10-8011-4cef-a957-c42f416ad1d3","added_by":"auto","created_at":"2025-04-28 16:11:29","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2929988,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5668721/v1/7ae10bec-dd56-4eb5-99f1-441f8698f2ae.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Five year’s outcomes of Trabeculo-Canalectomy for Chinese PACG Patients: a retrospective study","fulltext":[{"header":"Background","content":"\u003cp\u003ePrimary angle-closure glaucoma (PACG), a major subtype of glaucoma, accounts for 50% of all glaucoma-related cases of blindness worldwide [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. The number of PACG patients is estimated to reach 32.04\u0026nbsp;million by 2040 globally, three quarters of which occur in Asia [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], indicating that PACG has become a worldwide public health burden [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eGiven that PACG arises from anatomical derangement of the anterior segment, all treatment strategies aim at repairing anatomical defects and reducing intraocular pressure (IOP) [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Cataract surgery with or without trabeculectomy (Trab) is advocated as the initial treatment for PACG patients with younger ages, clear lens and diffused peripheral anterior synechiae (\u0026gt;\u0026thinsp;180 degrees) [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan additionalcitationids=\"CR8\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. However, its efficacy is significantly reduced by excessively low or high filtration that inevitably leads to hypotony, shallow anterior chamber, scars, and other complications [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Therefore, Trab should be modified to improve efficacy and reduce complications in the treatment of glaucoma.\u003c/p\u003e \u003cp\u003eTrab was first proposed by Cairns [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. In about two-thirds of Cairns\u0026rsquo; cases, IOP can be continuously controlled without subconjunctival drainage to aqueous humor [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. As suggested by Carins, this surgical technique can reduce IOP in chronic simple glaucoma by relieving trabecular obstruction without intentionally creating external drainage. Cairns lays out a rationale for us to design trabeculo-canalectomy [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. In PACG patients, the anterior chamber angle is blocked by anatomical alterations, thus impeding the aqueous humor flowing through [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e] while the post-trabecular outflow pathway may remain intact [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. A direct communication between the anterior chamber and the Schlemm\u0026rsquo;s canal can restore aqueous humor outflow in PACG patients [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Thus, it is theoretically possible to re-establish this communication for reducing IOP independent of a filtration bleb.\u003c/p\u003e \u003cp\u003eHerein, we modified Trab into trabeculo-canalectomy, by draining the aqueous humor from the cut end of Schlemm\u0026rsquo;s canal to re-establish good IOP control, without dependence on a filtration bleb and preventing post-surgery scarring. We evaluated its 5-year clinical outcomes in treating medically uncontrolled PACG eyes.\u003c/p\u003e"},{"header":"Materials and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy population\u003c/h2\u003e \u003cp\u003eEnrolled were 60 patients (70 eyes) treated with trabeculo-canalectomy in the First Affiliated Hospital of Nanjing Medical University, China, from January 2016 to December 2018. Of them, 14 patients (20 eyes, 28.57%) were excluded due to a follow-up of \u0026lt;\u0026thinsp;3 months. Finally, 46 patients (50 eyes) were included.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eInclusion Criteria\u003c/h3\u003e\n\u003cp\u003eInclusion criteria included\u003c/p\u003e \u003cp\u003e \u003col\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eAges 40 years or above;\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eMedically uncontrolled PACG and peripheral anterior synechiae of more than 180\u0026deg;;\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eUncontrolled PACG defined as IOP\u0026thinsp;\u0026gt;\u0026thinsp;21 mmHg for at least three consecutive measurements within previous one month, and on two or more glaucoma medications in the presence of glaucomatous optic disc neuropathy and visual field deficiency;\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eBest corrected visual acuity (LogMAR)\u0026thinsp;\u0026le;\u0026thinsp;0.3 without obvious lens opacity.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003c/ol\u003e \u003c/p\u003e\n\u003ch3\u003eExclusion criteria\u003c/h3\u003e\n\u003cp\u003eExclusion criteria included\u003c/p\u003e \u003cp\u003e \u003col\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003ePrimary open angle glaucoma, neovascular glaucoma, normal tension glaucoma, traumatic glaucoma, and secondary glaucoma;\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eOther histories of fundus disease and eye surgery (except for laser periphery iridotomy or iridoplasty);\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eSigns of suprascleral venous hypertension (e.g., torturous and dilated suprascleral veins);\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eSevere heart, lung disease, and advanced cancer;\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eA history of mental illness;\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003ePrevious treatment with anticoagulant therapy and kidney dialysis or pregnancy;\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eNo informed consent;\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eIncapability to adhere to the follow-up schedule required by this study.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003c/ol\u003e \u003c/p\u003e\n\u003ch3\u003eSurgical Procedures\u003c/h3\u003e\n\u003cp\u003eAll surgeries were performed by one designated experienced surgeon at the First Affiliated Hospital of Nanjing Medical University. 2.5 mL of 2% lidocaine\u0026thinsp;+\u0026thinsp;0.75% bupivacaine (mixed in a ratio of 1:1) was applied for peribulbar anesthesia. A suspension wire was made of 8\u0026thinsp;\u0026minus;\u0026thinsp;0 absorbable suture in the corneal limbus. A fornix-based incision through the conjunctiva and Tenon's capsule was made. Then, a 4\u0026times;4 mm superficial scleral flap in 1/2 scleral thickness was sculpted \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ea). Schlemm\u0026rsquo;s canal was located (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eb), its outer wall opened (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ec-d), and then this wall and the trabecular meshwork measuring 1\u0026times;2 mm removed (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ee). Following resection of the peripheral iris at 12 o\u0026rsquo;clock (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ef), moderate viscoelastic agents were injected under the scleral flap to reinsert the iris (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eg). The scleral flap was closed tightly with two sutures of 10\u0026thinsp;\u0026minus;\u0026thinsp;0 nylon (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eh). The conjunctiva-Tenon's layer was sutured with 10\u0026thinsp;\u0026minus;\u0026thinsp;0 nylon at the ends of the incision (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ei). The corneal side port incisions were hydrated and made watertight. Antimetabolic agents such as mitomycin C or 5- fluorouracil were not used intraoperatively.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e\n\u003ch3\u003eObservational Indexes\u003c/h3\u003e\n\u003cp\u003ePostoperative follow-up was made at 1 week, 1 month, 3 months, 6 months, 12 months, 1 year, 2 years and 5 years, with additional visits whenever necessary, for documentation of IOP, number of anti-glaucoma regimens, best corrected visual acuity (BCVA), results of anterior and posterior segment examination, frequency of complications, postoperative interventions and morphology of filtering blebs.\u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eEvaluation of Surgical Success or Failure\u003c/h2\u003e \u003cp\u003eEvaluation of surgical success or failure included[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]\u003cdiv class=\"BlockQuote\"\u003e\u003cp\u003e(1) Complete success: post-operative IOP at 6 to 21 mmHg without anti-glaucoma medications;\u003c/p\u003e\u003cp\u003e(2) Conditional success: post-operative IOP at 6 to 21 mmHg with local application of anti-glaucoma medications;\u003c/p\u003e\u003cp\u003e(3) Failure: post-operative IOP lower than 6 mmHg or higher than 21 mmHg after application of anti-glaucoma medications. In these cases, severe complications were observed, such as retinal detachment and endophthalmitis.\u003c/p\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eThe extent and height of filtering blebs were graded by Indiana Bleb Appearance Grading Scale (IBAGS) [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Bleb height referred to the vertical dimension of the filtering bleb and represented the elevation of the conjunctival flap above the scleral surface. The height of the bleb was divided into four levels: H0, flat without visible elevation; H1, slight elevation; H2, moderate elevation; and H3, significant elevation as compared with the standard images. Bleb extent represented the horizontal dimension of the filtering bleb, or bleb area. This extent was also divided into four levels: E0, no visible extent (within less than 1 clock); E1, extent between 1 clock and 2 clock hours; E2, extent between 2 clock and 4 clock hours; and E3, extent beyond 4 clock hours.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eSPSS version 21.0 was used for statistical analyses. Continuous variables were summarized as means, standard deviations, medians, and ranges; categorical variables as frequencies and percentages. Student\u0026rsquo;s \u003cem\u003et\u003c/em\u003e test was performed for comparison between groups, and one-way ANOVA for comparison among three or more groups. Statistical significance was defined by a \u003cem\u003eP\u003c/em\u003e value\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eA total of 46 PACG patients (50 eyes), including 17 men, were recruited in this study, with a mean age of 56.68\u0026thinsp;\u0026plusmn;\u0026thinsp;6.75 years (range 41\u0026ndash;69 years), an average preoperative IOP of 30.72\u0026thinsp;\u0026plusmn;\u0026thinsp;10.26 mmHg, and a median (range) number of medication regimens of 2 (0\u0026thinsp;~\u0026thinsp;4). Patient characteristics are presented in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eThe basic data for patient enrollments.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCharacteristics\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eValues\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNo. of eyes/patients\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e50/46\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOD/OS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e19/31\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGender (male/female)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e17/33\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e56.68\u0026thinsp;\u0026plusmn;\u0026thinsp;6.75\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePreoperative IOP (mmHg)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e30.72\u0026thinsp;\u0026plusmn;\u0026thinsp;10.26\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePreoperative medications\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.26\u0026thinsp;\u0026plusmn;\u0026thinsp;0.83\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePreoperative BCVA (LogMAR)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.21\u0026thinsp;\u0026plusmn;\u0026thinsp;0.08\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHistory of LPI (n, %)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e26(52%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ephakic eye (n, %)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e50(100%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eData were expressed as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD. BCVA\u0026thinsp;=\u0026thinsp;best-corrected visual acuity, IOP\u0026thinsp;=\u0026thinsp;intraocular pressure, LPI\u0026thinsp;=\u0026thinsp;laser peripheral iridotomy, SD\u0026thinsp;=\u0026thinsp;standard deviation.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe mean postoperative IOP decreased from the preoperative 30.72\u0026thinsp;\u0026plusmn;\u0026thinsp;10.26 to 12.15\u0026thinsp;\u0026plusmn;\u0026thinsp;3.11, 14.33\u0026thinsp;\u0026plusmn;\u0026thinsp;4.10, 15.68\u0026thinsp;\u0026plusmn;\u0026thinsp;4.24, 16.45\u0026thinsp;\u0026plusmn;\u0026thinsp;4.14, 16.95\u0026thinsp;\u0026plusmn;\u0026thinsp;3.51, 17.67\u0026thinsp;\u0026plusmn;\u0026thinsp;3.15 and 17.04\u0026thinsp;\u0026plusmn;\u0026thinsp;3.78 mmHg at 1 week, 1 month, 3 months, 6 months, 1 year, 2 years and 5 years, respectively (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The difference between the mean IOP values at baseline and each follow-up point was statistically significant (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001, Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The median (range) numbers of medication regimens were 0 (0\u0026thinsp;~\u0026thinsp;1), 0 (0\u0026thinsp;~\u0026thinsp;2), 0 (0\u0026thinsp;~\u0026thinsp;2), 0 (0\u0026thinsp;~\u0026thinsp;2), 0 (0\u0026thinsp;~\u0026thinsp;2), 0 (0\u0026thinsp;~\u0026thinsp;3), 0 (0\u0026thinsp;~\u0026thinsp;3) at the seven time points, respectively (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The difference between the numbers of anti-glaucoma regimens at baseline and each follow-up point was statistically significant (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001, Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). BCVA at post-operative 5 years was 0.23\u0026thinsp;\u0026plusmn;\u0026thinsp;0.11, and not different from that at baseline (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.388).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eIOP and medications of the patients completed trabeculo-canalectomy.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFollow-up time\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eN\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eIOP (mmHg)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eEyes with meds/tota(%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eNumber of meds regimens\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePre-operation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e30.72\u0026thinsp;\u0026plusmn;\u0026thinsp;10.26\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e50(100)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.26\u0026thinsp;\u0026plusmn;\u0026thinsp;0.83\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1 wk\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e12.15\u0026thinsp;\u0026plusmn;\u0026thinsp;3.11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1(2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.02\u0026thinsp;\u0026plusmn;\u0026thinsp;0.14\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1 mo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14.33\u0026thinsp;\u0026plusmn;\u0026thinsp;4.10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6(12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.10\u0026thinsp;\u0026plusmn;\u0026thinsp;0.36\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3 mo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e15.68\u0026thinsp;\u0026plusmn;\u0026thinsp;4.24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7(14)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.18\u0026thinsp;\u0026plusmn;\u0026thinsp;0.48\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e6 mo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e16.45\u0026thinsp;\u0026plusmn;\u0026thinsp;4.14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e13(26)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.34\u0026thinsp;\u0026plusmn;\u0026thinsp;0.63\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1 y\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e16.95\u0026thinsp;\u0026plusmn;\u0026thinsp;3.51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e15(30)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.42\u0026thinsp;\u0026plusmn;\u0026thinsp;0.73\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2 y\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e17.67\u0026thinsp;\u0026plusmn;\u0026thinsp;3.15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e14(34.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.54\u0026thinsp;\u0026plusmn;\u0026thinsp;0.84\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e5 y\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e36\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e17.04\u0026thinsp;\u0026plusmn;\u0026thinsp;3.78\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e13(36.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.58\u0026thinsp;\u0026plusmn;\u0026thinsp;0.91\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e-value\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003csup\u003e\u0026dagger;\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e \u003cp\u003eData were expressed as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e \u003cp\u003eIOP\u0026thinsp;=\u0026thinsp;intraocular pressure, SD\u0026thinsp;=\u0026thinsp;standard deviation, meds\u0026thinsp;=\u0026thinsp;medications.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e \u003cp\u003e*One-way repeated measure ANOVA analysis.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e \u003cp\u003e\u003csup\u003e\u0026dagger;\u003c/sup\u003eChi-square analysis.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe total success rate of surgery was 89% at 5 years, including the complete success rate 78% and the conditional success rate 11% (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). According to IBAGS, the filtering bleb in 5 (10%) eyes was graded as E1H1 at 1 week after surgery. Ultrasound biomicroscopy and anterior segment slit-lamp photography showed that 50 eyes (100%) had no obvious filtering bleb (E0H0) at 3 months (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Shallow anterior chamber (10%) and hyphema (12%) were the most common complications early after surgery. IOP elevated in 6 eyes (12%) transiently within 1 month after surgery, and was reduced after topical use of glaucoma medications. No blebitis, hypotony, choroidal detachment, malignant glaucoma and endophthalmitis were observed.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eRates of absolute and qualified successes.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"8\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFollow-up time\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 wk\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1 mo\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3 mo\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e6 mo\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1 y\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2 y\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003e5 y\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSUM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e36\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal success, N (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e50(100%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e47(94%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e48(96%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e45(90%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e46(92%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e37(90%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e32(89%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAbsolute success, N (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e50(100%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e44(88%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e42(84%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e36(72%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e35(70%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e27(66%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e22(78%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eQualified success, N (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3(6%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6(12%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e9(18%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e11(22%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e10(24%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e10(11%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"8\" nameend=\"c8\" namest=\"c1\"\u003e \u003cp\u003eSUM: summary; N: number.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eTrab is the primary approach to treat glaucoma; however, vision-threatening complications may occur in 39% of Trab-treated cases, 74% of which need urgent postoperative interventions [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Moreover, bleb-related complications may persist, regardless of IOP well controlled after surgery [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. Additionally, scarring in the filtering bleb often leads to treatment failure [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Thus, anti-scarring and bleb-independent surgical procedures remain to be developed.\u003c/p\u003e \u003cp\u003eIn the present study, we reported the 5-year outcomes of bleb-independent trabeculo-canalectomy, a novel procedure. At five years, trabeculo-canalectomy achieved a total success rate of 89% (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e), suggesting its superior therapeutic effects in comparison with previous literatures [\u003cspan additionalcitationids=\"CR21 CR22\" citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. Surgical complications mainly occurred within 1 month after surgery, including shallow anterior chamber (10%), hyphema (12%), and transient IOP elevation (12%). A filtering bleb was not needed after trabeculo-canalectomy. This surgery provides a new option for PACG patients.\u003c/p\u003e \u003cp\u003eTrab, initially described by Cairns in 1968 [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e], has been considered as the \u0026ldquo;gold standard\u0026rdquo; for filtration surgery [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Initially, this operation aims to remove the Schlemm\u0026rsquo;s canal and trabecular meshwork and form a natural pathway for aqueous to egress the eye, in addition to bleb formation. But, later histopathologic examinations recognized that what the surgeons mostly remove was not Schlemm\u0026rsquo;s canal or trabecular meshwork, but the peripheral cornea, and IOP reduction is mainly due to filtering bleb formation. Then, Trab was modified as an \u0026ldquo;externo technique\u0026rdquo; by surgeons. Previous studies have shown that the effect of Trab fails in about 30% cases at 3 years, and nearly 50% at 5 years [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e], mainly due to the formation of scar tissue in the conjunctiva, the tenon capsule and the interocular membrane as the natural reaction to wound healing [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIt is worth noting that trabeculo-canalectomy reported in this study might revolutionize the surgical concept of \u0026ldquo;external filtration\u0026rdquo; by reconstructing a physiological drainage channel for the treatment of PACG. It proves an \u0026ldquo;internal filtration\u0026rdquo; and bleb-independent procedure that prevents the occurrence of filtration bubble scarring. With the excision of a portion of the Schlemm\u0026rsquo; Canal with its trabecular covering, two cut ends were left open into aqueous humor, thus restoring the integrity of the corneoscleral coat over the excision (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ea-e). These procedures enabled tight suturing of the conjunctival flap and scleral flap (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eh-i), absence of filtering blebs (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e), and well controlled IOP (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eTrabeculo-canalectomy, which is bleb-independent, significantly reduces the incidence of filtering bleb- and antimetabolite-related complications, which are frequent in trabeculectomy [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan additionalcitationids=\"CR27\" citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. Additionally, post-operative interventions of filtering blebs [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e], such as releasable sutures and bleb needling, were not necessarily performed in our research. Third, tight suturing of the conjunctival flap and scleral flap significantly reduces complications early after surgery [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e], such as hypotony and shallow anterior chamber related to over-filtration. Hypotony occurs in 10\u0026ndash;37.5% cases after traditional Trab [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e], but none after trabeculo-canalectomy in the present study. In summary, trabeculo-canalectomy facilitates aqueous outflow and restores filtration through Schlemm\u0026rsquo;s canal, demonstrating long-term efficacy and safety for PACG patients.\u003c/p\u003e \u003cp\u003eDesigned according to a concept of \u0026ldquo;internal drainage\u0026rdquo; (similar to ours), penetrating Schlemm canaloplasty has been first composed by Professor Liang in 2015, and also achieved remarkable clinical success [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan additionalcitationids=\"CR33 CR34\" citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. In this surgery, a direct communication is established between the anterior chamber and the Schlemm\u0026rsquo;s canal to restore aqueous humor outflow in PACG patients, thus combining the advantages of suture tensioning canaloplasty with Trab. The success rate of this surgery can reach 86.8% in PACG patients [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]. However, in Liang\u0026rsquo;s surgery, Schlemm\u0026rsquo;s canal needs to be perforated by microcatheter throughout the operation, and tensioning suture serves to keep Schlemm\u0026rsquo;s canal patent [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. As a consequence, this surgery procedure is relatively complex for clinicians, and their long learning curve may also lead to clinical failure in some cases. Additionally, the microcatheter used during the procedure is expensive [\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn comparison, our trabeculo-canalectomy is relatively simple and cost-saving, mainly including the following steps: a superficial scleral flap, 4\u0026times;4 mm and 1/2 scleral thickness, was forwarded into the clear corneal limbus by about 1mm. Then, the clear corneal area and the white sclera area were identified. The gray zone, also known as the grayish blue trabecular meshwork, was delineated. The Schlemm\u0026rsquo;s canal runs at the junction between the grayish blue trabecular meshwork and the white sclera, and the Schlemm tube was accurately located at the posterior 1/2 of the gray area (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eb). At this time, the outer wall of the Schlemm\u0026rsquo;s canal was gently lifted by microscope forceps, and then opened to expose its cavity more easily (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eb-c). Before opening the Schlemm\u0026rsquo;s canal, anterior chamber paracentesis was performed to prevent the iris from excessively prolapsing to the incision site. Since the Schlemm\u0026rsquo;s canal is close to the root of the iris, it is recommended to clip the iris slightly away from the Schlemm\u0026rsquo;s canal and perform iridectomy to reduce iris bleeding (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ef). The scleral and conjunctival flaps were tightly sutured with 10\u0026thinsp;\u0026minus;\u0026thinsp;0 nylon suture to avoid early filtration (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eh-i).\u003c/p\u003e \u003cp\u003eNotably, though simple and cost-saving trabeculo-canalectomy provides favorable 5-year outcomes in the treatment of PACG, the procedure may not achieve similar efficacy in patients with certain types of glaucoma, the pathophysiology of which may lie beyond the Schlemm\u0026rsquo;s canal, such as primary open-angle glaucoma (POAG). The developmental abnormalities in the outflow routes and collapse of Schlemm lumen have been reported in POAG patients [\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e]. The cutting ends of Schlemm\u0026rsquo;s canal may be more prone to the occurrence of adhesion and closure in POAG patients. In addition, our previous research shows that patients with secondary glaucoma, especially uveitic glaucoma, were more likely to undergo surgical failure[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Adequate anti-inflammatory therapy combined with antimetabolic drugs is often needed in the surgical treatment of uveitic glaucoma.\u003c/p\u003e \u003cp\u003eThere are some limitations in this study. First of all, only PACG patients in China were included, and our surgery may not be suitable to PACG patients in other countries. Part of the patients included were binocular, and the statistical results may have been biased. Second, the sample size of this study was small. In addition, aqueous oozing from the Decemet\u0026rsquo;s membrane and trabecular meshwork is a marker for the positioning of the canal of Schlemm. However, due to the extensive peripheral anterior synechiae and obstruction of the trabecular meshwork, aqueous oozing is infrequent in PACG eyes, thus challenging the recognition of the Schlemm\u0026rsquo;s canal in PACG patients. This requires a learning curve for a surgeon. More randomized controlled trials should be conducted in the near future to directly compare the efficacy, safety and cost-effectiveness of this procedure with Trab.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eTabeculo-canalectomy provides favorable 5-year outcomes in treating medically uncontrolled PACG, as shown by effective IOP control, obvious drug reduction, as well as less post-operative interventions compared to Trab.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"351\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 68px;\"\u003e\n \u003cp\u003ePACG\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 283px;\"\u003e\n \u003cp\u003ePrimary angle-closure glaucoma\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 68px;\"\u003e\n \u003cp\u003ePOAG\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 283px;\"\u003e\n \u003cp\u003ePrimary angle-open glaucoma\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eIOP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eIntraocular pressure\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eTrab\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eTrabeculectomy\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eIBAGS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eIndiana Bleb Appearance Grading Scale\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eBCVA\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eBest-corrected visual acuity\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eLPI\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eLaser peripheral iridotomy\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eSD\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eStandard deviation\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eMeds\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eMedications\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eSUM\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eSummary\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003e\u0026nbsp;N\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eNumber\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe would like to thank Yong-ke Cao for proofreading of the manuscript.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; contribution\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eZX, THX, PX and HS designed the research project; ZX, THX, JLH, and PZ performed the research; ZX and MLD analyzed the data; ZX wrote the manuscript draft; MLD, YTZ, PX and HS revised the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was supported by a grant from the National Natural Science Foundation of China (Grant Number: 82401281).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis was a retrospective\u0026nbsp;study\u0026nbsp;approved by the First Affiliated Hospital of Nanjing Medical University (No.2023-SR-474), abiding by the\u003cem\u003e\u0026nbsp;Declaration of Helsinki\u003c/em\u003e. Written consent was obtained from all patients before surgery.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eSong Y, Zhang H, Zhang Y, Tang G, Wan KH, Lee JWY, Congdon N, Zhang M, He M, Tham CC\u003cem\u003e et al\u003c/em\u003e: \u003cstrong\u003eMinimally Invasive Glaucoma Surgery in Primary Angle-Closure Glaucoma\u003c/strong\u003e. \u003cem\u003eAsia Pac J Ophthalmol (Phila) \u003c/em\u003e2022, \u003cstrong\u003e11\u003c/strong\u003e(5):460-469.\u003c/li\u003e\n\u003cli\u003eSong Y, Lin F, Lv A, Zhang Y, Lu L, Xie L, Tang G, Yuan H, Yang Y, Xu J\u003cem\u003e et al\u003c/em\u003e: \u003cstrong\u003ePhacogoniotomy versus phacotrabeculectomy for advanced primary angle-closure glaucoma with cataract: A randomized non-inferiority trial\u003c/strong\u003e. \u003cem\u003eAsia Pac J Ophthalmol (Phila) \u003c/em\u003e2024, \u003cstrong\u003e13\u003c/strong\u003e(1):100033.\u003c/li\u003e\n\u003cli\u003eLee J, Park JS, Jeong Y, Shin YI, Huh MG, Jeoung JW, Park KH, Kim YK: \u003cstrong\u003ePrevalence Ratio of Primary Angle-Closure and Primary Open-Angle Glaucoma in Asian Population: A Meta-Analysis and Multiple Meta-Regression Analysis\u003c/strong\u003e. \u003cem\u003eKorean J Ophthalmol \u003c/em\u003e2024, \u003cstrong\u003e38\u003c/strong\u003e(1):42-50.\u003c/li\u003e\n\u003cli\u003eTham YC, Li X, Wong TY, Quigley HA, Aung T, Cheng CY: \u003cstrong\u003eGlobal prevalence of glaucoma and projections of glaucoma burden through 2040: a systematic review and meta-analysis\u003c/strong\u003e. \u003cem\u003eOphthalmology \u003c/em\u003e2014, \u003cstrong\u003e121\u003c/strong\u003e(11):2081-2090.\u003c/li\u003e\n\u003cli\u003eLiang YB, Wang NL, Rong SS, Thomas R: \u003cstrong\u003eInitial Treatment for Primary Angle-Closure Glaucoma in China\u003c/strong\u003e. \u003cem\u003eJ Glaucoma \u003c/em\u003e2015, \u003cstrong\u003e24\u003c/strong\u003e(6):469-473.\u003c/li\u003e\n\u003cli\u003eZhang N, Wang J, Chen B, Li Y, Jiang B: \u003cstrong\u003ePrevalence of Primary Angle Closure Glaucoma in the Last 20 Years: A Meta-Analysis and Systematic Review\u003c/strong\u003e. \u003cem\u003eFront Med (Lausanne) \u003c/em\u003e2020, \u003cstrong\u003e7\u003c/strong\u003e:624179.\u003c/li\u003e\n\u003cli\u003eHusain R, Do T, Lai J, Kitnarong N, Nongpiur ME, Perera SA, Ho CL, Lim SK, Aung T: \u003cstrong\u003eEfficacy of Phacoemulsification Alone vs Phacoemulsification With Goniosynechialysis in Patients With Primary Angle-Closure Disease: A Randomized Clinical Trial\u003c/strong\u003e. \u003cem\u003eJAMA Ophthalmol \u003c/em\u003e2019, \u003cstrong\u003e137\u003c/strong\u003e(10):1107-1113.\u003c/li\u003e\n\u003cli\u003eNie L, Fu L, Chan YK, Fang A, Pan W: \u003cstrong\u003eCombined Phacoemulsification With Goniosynechialysis Under Ophthalmic Endoscope for Primary Angle-closure Glaucoma After Failed Trabeculectomy\u003c/strong\u003e. \u003cem\u003eJ Glaucoma \u003c/em\u003e2020, \u003cstrong\u003e29\u003c/strong\u003e(10):941-947.\u003c/li\u003e\n\u003cli\u003eZhang S, Hu C, Cheng H, Gu J, Samuel K, Lin H, Deng Y, Xie Y, Hu J, Le R\u003cem\u003e et al\u003c/em\u003e: \u003cstrong\u003eEfficacy of bleb-independent penetrating canaloplasty in primary angle-closure glaucoma: one-year results\u003c/strong\u003e. \u003cem\u003eActa Ophthalmol \u003c/em\u003e2022, \u003cstrong\u003e100\u003c/strong\u003e(1):e213-e220.\u003c/li\u003e\n\u003cli\u003eBahlmann D, van Oterendorp C: \u003cstrong\u003e[Glaucoma Filtration Surgery - Bleb-forming Procedures]\u003c/strong\u003e. \u003cem\u003eKlin Monbl Augenheilkd \u003c/em\u003e2024, \u003cstrong\u003e241\u003c/strong\u003e(7):863-880.\u003c/li\u003e\n\u003cli\u003ePetrov SY, Vostrukhin SV, Aslamazova AE, Sherstneva LV: \u003cstrong\u003e[Modern methods of minimally invasive glaucoma surgery]\u003c/strong\u003e. \u003cem\u003eVestn Oftalmol \u003c/em\u003e2016, \u003cstrong\u003e132\u003c/strong\u003e(3):96-102.\u003c/li\u003e\n\u003cli\u003eCairns JE: \u003cstrong\u003eTrabeculectomy. 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\u003cstrong\u003e[Preliminary efficacy of penetrating canaloplasty in primary angle-closure glaucoma]\u003c/strong\u003e. \u003cem\u003eZhonghua Yan Ke Za Zhi \u003c/em\u003e2019, \u003cstrong\u003e55\u003c/strong\u003e(6):448-453.\u003c/li\u003e\n\u003cli\u003eLiang Y, Yu Q, Sun H, Sucijanti, Gu L, Yuan Z: \u003cstrong\u003eModified suture-assisted canaloplasty in Asians with primary open-angle glaucoma: a prospective study with 12-month follow-up\u003c/strong\u003e. \u003cem\u003eBMC Ophthalmol \u003c/em\u003e2022, \u003cstrong\u003e22\u003c/strong\u003e(1):202.\u003c/li\u003e\n\u003cli\u003eHamanaka T, Sakurai T, Fuse N, Ishida N, Kumasaka T, Tanito M: \u003cstrong\u003eComparisons of Schlemm\u0026apos;s canal and trabecular meshwork morphologies between juvenile and primary open angle glaucoma\u003c/strong\u003e. \u003cem\u003eExp Eye Res \u003c/em\u003e2021, \u003cstrong\u003e210\u003c/strong\u003e:108711.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-ophthalmology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"boph","sideBox":"Learn more about [BMC Ophthalmology](http://bmcophthalmol.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/boph","title":"BMC Ophthalmology","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Primary angle-closure glaucoma, trabeculo-canalectomy, Schlemm’s canal, 5-year outcome","lastPublishedDoi":"10.21203/rs.3.rs-5668721/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5668721/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eTo evaluate the 5-year outcomes of trabeculo-canalectomy in the treatment of primary angle-closure glaucoma (PACG) among Chinese patients.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eA retrospective study was designed, involving 46 PACG patients (50 eyes) treated with trabeculo-canalectomy at the First Affiliated Hospital of Nanjing Medical University from January 2016 to December 2018. The patients were followed up at 1 week, 1 month, 3 months, 6 months, 12 months, 1 year, 2 years and 5 years. Surgical success was defined as intraocular pressure (IOP)\u0026thinsp;\u0026le;\u0026thinsp;21 mmHg (1 mmHg\u0026thinsp;=\u0026thinsp;0.133 kPa) under glaucoma medication (qualified success) and without any glaucoma medication (absolute success). Main outcomes were measured according to IOP, number of medication regimens, surgical success rate, complications, and filtering bleb status.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eA total of 46 PACG patients (50 eyes) were finally included for statistical analysis, with a mean age of 56.68\u0026thinsp;\u0026plusmn;\u0026thinsp;6.75 years (range, 41\u0026ndash;69 years). The mean preoperative IOP was 30.72\u0026thinsp;\u0026plusmn;\u0026thinsp;10.26 mmHg with a median number of medication regimens of 2 (range, 0 to 4). Compared to those before the operation, the mean IOP decreased to 12.15\u0026thinsp;\u0026plusmn;\u0026thinsp;3.11, 14.33\u0026thinsp;\u0026plusmn;\u0026thinsp;4.10, 15.68\u0026thinsp;\u0026plusmn;\u0026thinsp;4.24, 16.45\u0026thinsp;\u0026plusmn;\u0026thinsp;4.14, 16.95\u0026thinsp;\u0026plusmn;\u0026thinsp;3.51, 17.67\u0026thinsp;\u0026plusmn;\u0026thinsp;3.15 and 17.04\u0026thinsp;\u0026plusmn;\u0026thinsp;3.78 mmHg at 1 week, 1 month, 3 months, 6 months, 12 months, 1 year, 2 years and 5 years, respectively. The median (range) numbers of medication regimens were 0 (0\u0026thinsp;~\u0026thinsp;1), 0 (0\u0026thinsp;~\u0026thinsp;2), 0 (0\u0026thinsp;~\u0026thinsp;2), 0 (0\u0026thinsp;~\u0026thinsp;2), 0 (0\u0026thinsp;~\u0026thinsp;2), 0 (0\u0026thinsp;~\u0026thinsp;3), 0 (0\u0026thinsp;~\u0026thinsp;3), 0 (0\u0026thinsp;~\u0026thinsp;3) at the eight time points, respectively. The mean postoperative IOP and the number of medication regimens at each time point were significantly lower than those before operation (all \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01). The 5-year total success rate was 89%, and the absolute success rate was 78%. Shallow anterior chamber (10%) and hyphema (12%) were the most common complications early after surgery. At 3 months, anterior segment slit-lamp photography and ultrasound biomicroscopy showed no obvious filtering blebs in 50 eyes (100%). IOP increased transiently in 6 eyes (12%) within 1 month after surgery.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eSimple and cost-saving trabeculo-canalectomy provides favorable 5-year outcomes in the treatment of medically uncontrolled PACG, as shown by more effective IOP control, more obvious drug reduction, as well as fewer post-operative interventions compared to trabeculectomy.\u003c/p\u003e","manuscriptTitle":"Five year’s outcomes of Trabeculo-Canalectomy for Chinese PACG Patients: a retrospective study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-04-04 10:59:18","doi":"10.21203/rs.3.rs-5668721/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Accepted","date":"2025-04-09T02:31:52+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-04-08T11:27:37+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"222455661588251781357223586882327617010","date":"2025-04-07T08:28:53+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-04-04T06:31:43+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"68854255685757163668683526481040272786","date":"2025-04-04T06:14:26+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-04-03T03:12:37+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-03-28T12:25:01+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Ophthalmology","date":"2025-03-27T11:03:44+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-ophthalmology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"boph","sideBox":"Learn more about [BMC Ophthalmology](http://bmcophthalmol.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/boph","title":"BMC Ophthalmology","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"3ec8a4c9-b38d-46b9-9b14-86bd08e19756","owner":[],"postedDate":"April 4th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-04-28T16:05:10+00:00","versionOfRecord":{"articleIdentity":"rs-5668721","link":"https://doi.org/10.1186/s12886-025-04051-6","journal":{"identity":"bmc-ophthalmology","isVorOnly":false,"title":"BMC Ophthalmology"},"publishedOn":"2025-04-22 15:57:22","publishedOnDateReadable":"April 22nd, 2025"},"versionCreatedAt":"2025-04-04 10:59:18","video":"","vorDoi":"10.1186/s12886-025-04051-6","vorDoiUrl":"https://doi.org/10.1186/s12886-025-04051-6","workflowStages":[]},"version":"v1","identity":"rs-5668721","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5668721","identity":"rs-5668721","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}