ONE SITE VERSUS TWO SITE PHACOTRABECULECTOMY : RANDOMIZED CLINICAL TRIAL

Soha moussa mohamed eltohamy. Purpose:To compare one-site versus two-site phacotrabeculectomy in patients with visually significant cataract and primary open-angle glaucoma (POAG), with regard to achieve target intraocular pressure (IOP) and best visual acuity (VA). Method:Forty patients (40 eyes) with coexistance glaucoma and cataract were randomly assigned to undergo either a one-site (20 eyes) or a two-site (20 eyes) phacotrabeculoectomy. One-site approach consisted of a standard superior phacotrabeculectomy , while two-site approach consisted of a clear cornea phacoemulsification and a separate superior trabeculectomy. Results:Mean preoperative intraocular pressure (IOP) in the one-site group was 22.05 mmHg (SD 1.6) and in the two-site group was 22.4 mmHg (SD 1.8) (P 0.4) using a mean of 2.6 (SD 0.5), 2.7(SD 0.4) antiglaucomatus medication (AM), respectively (p 0.56). Aftesr thirty months of follow-up, the. Mean postoperative IOP significantly decreased in both groups compared to the preoperative level and was 14.2 mmHg (SD 1.06) in the one-site group and 13.5 mmHg (SD 1.19) in the two-site group (p 0.07) , using a mean of 0.3 (SD 0.47), and 0.25 (SD 0.44) A M, respectively. Mean IOP and AM postoperatively were significantly less compared to preoperatively for each group (p < 0.05).AS regard postoperative IOP, the two sites has more reduction of IOP than one site bu not statistically significant difference (p 0.07). AS regard postoperative AM two sites has less AM than one site to control IOP , but not statistically significant difference(p 0.94) . AS regard postoperative best-corrected visual acuity (BCVA), the two site had better (BCVA) than the one site, but the difference was not statistically significant (P 0.97). There was less postoperative (induced) astigmatism in the two-site group and the difference was statistically significant ((p 0.01). Conclusion:Both one-site and two-site phacotrabeculectomy had similar results concerning final BCVA and IOP reduction. However, the two-site group had less induced astigmatism and a better postoperative IOP control with less required postoperative antiglaucoma medications compared to the one-site group.


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The primary angle-closure glaucoma (PACG) is caused by obstruction of aqueous fluid outflow through the iridocorneal angle causing elevation of the intraocular pressure (IOP) and optic nerve damage.So, IOP reduction is essential for the protection of visual function. 1 Phacoemulsification surgery produce less inflammation and fibrosis at the site of the incision than extracapsular cataract extraction. 2 The advantage of clear cornea approach is that the conjunctiva is intact with minimal distortion to the angle. 3 although, phacoemulsification is better than extracapsular cataract extraction for mangement of patients with visually significant cataract and glaucoma that is not adequately controlled with topical medication, but it may cause a significant short-term intraocular pressure (IOP) rise in the early postoperative period. 4 If trabeculectomy is only done, the preexisting cataract will progress. [5][6][7][8] Co-mangement of glaucoma and cataract by phacotrabeculectomy has the advantage of early visual rehabilitation and adequate control of glaucoma.
Phacotrabeculectomy is consisted phacoemulsification and trabeculectomy which is performed through the same incision (one site) or two separate incisions (two sites) 9 .
If phacoemulcification incision separates from the trabeculectomy incision,It reduces postoperative scarring of the scleral flap and conjuctiva and improves the results of the filtration surgery 10 .
The purpose of this study was to compare prospectively the results of one site versus two-site phacotrabeculectomy as regard to VA, IOP, and glaucoma medication requirements .

Materials and methods:-
The current study is a prospective, randomized controlled trial conducted upon 40 cases who attended ophthalmology clinic of benha university hospital during aperiod of thirty months . Inclusion Criteria were the presence glaucoma and visually significant cataract . . Visually significant cataract means a cataract that reduced the best-corrected visual acuity (BCVA) more than five lines in the Snellen chart. All patients had POAG with inadequate control of IOP(more than 21 mmHg) or requiring two or more antiglaucoma medications. All patients had typical glaucoma visual defect by automated perimetry (Humphrey perimetry threshold 30.2 or 24.2) and also progression of glaucoma damage (perimetry testing and C/D ratio evaluation).
Exclusion criteria were the presence of lens subluxation, neovascular glaucoma, advanced visual field loss, and/or excessive cupping of the disc or history of previous intraocular surgery, a history of uveitis, phacolytic or phacomorphic glaucoma, steroid-induced glaucoma, traumatic glaucoma or any ocular pathology that may affect final visual acuity. Patients were randomized into two groups: 1) Group I (n=20 eyes), who underwent one-site phacotrabeculectomy and 2) Group II (n=20 eyes), who underwent two-site phacotrabeculectomy. Written informed consent was obtained from all patients.

Procedures:-
One-site surgery:-A superior fornix-based conjunctival flap was done by incising the conjunctiva at the limbus and dissecting posteriorly. Hemostasis is performed by wet field bipolar electrocautery mainly at the site of choose sclera flap. A limited tenonectomy was made. A rectangular (3x4mm) partial (two third)-thickness scleral flap was dissected until clear cornea. Then a paracentesis was made by MVR, followed by injection of a viscoelastic. Avalved entry into the anterior chamber under the scleral flap was made using a 3.2-mm blade keratome. Phacoemulsification (capsulorhexis -hydrodisection and hydrodelinition -emulsification of nucleus -irrigation aspiration of cortical matter )then was performed. A foldable acrylic intraocular lens (IOL) was implanted into the capsular bag. Then aspiration of all viscoelastic and injection of acetylcholine to constrict the pupil. No antimetabolites were used. A trabeculectomy (1.5x2) was performed with a knife and Vannas scissors. The iris is pulled out and peripheral iridectomy was performed. The scleral flap was closed with two 10-0 nylon sutures at the corners, and the conjunctival flap was sutured with a mattress-type 10-0 nylon suture.Injection of a balanced salt solution through the paracentesis to deep anterior chamber, to detect leakage and test the function of the bleb. A subconjunctival injection of 0.25cc dexamethason 1mg/ml and 0.25cc gentamicin 40mg/ml in lower fornix.

Two-site surgery:-
The two-site procedure means that separation of trabeculectomy incision from that phacoemusification. that of consisted of trabeculectomy (which is done superiorly) and phacoemusification(which is performed temporally). A fornix-based conjunctival flap was fashioned superonasally. Minimal electrocautery (to reduce postoperative scaring) and a limited tenonectomy was performed. A rectangular (3x4mm) partial-thickness scleral flap was performed, without the use of antimetabolites. A phacoemulsification (capsulorhexis -hydrodisection and hydrodelinition -phacoemulsification of nucleus -irrigation aspiration of cortical matter) through a temporal clear corneal incision was performed, and a foldable acrylic posterior chamber IOL was inserted into the capsular bag . then dissection of scleral flap was advanced into clear cornea. The anterior chamber was entered with a 3.2-mm blade keratome The trabeculectomy was subsequently performed with a knife and Vannas scissors, followed by a peripheral iridectomy. The scleral flap was then sutured with two 10-0 nylon sutures. the conjunctival flap was sutured with 8-0 vicryl suture. Injection of a balanced salt solution through the paracentesis to deep anterior chamber, to detect leakage and test the function of the bleb. A subconjunctival injection of 0.25cc dexamethason 1mg/ml and 0.25cc gentamicin 40mg/ml in lower fornix.
All patients received the same postoperative regimen :A topical antibiotic were used three times daily for two weeks. Topical corticosteroids were given three times daily for the first two weeks, then reduced to two times daily for next a week and lastly one time for a weak were tapered slowly. patient data.

Patient data
Preoperative:-history of name, age, sex , the number of preoperative antiglaucoma medications, systemic diseases and history of laser and surgical operations.compelte ophthalmic examination included BCVA measurement, IOP measurement by Goldmann applanation tonometry and detection of any other ocular pathology that may affect final visual acuity.Operative:-include date of operation, surgical procedure (one-site or two-site phacotrabeculectomy), and the presence of any operative complications.postoperative : IOP was measured 24 hours after surgery, and then on the third day, one week, one month, and then every 3 months. If it was above 20 mmHg , an antiglaucoma medication was given. BCVA was measured at one month and then every 3 months . the presence of any postoperative complications and the number of antiglaucoma medications were recorded. SPSS version 14.0 (SPSS Inc., Chicago, IL) was used for the statistical analysis and p value less than 0.05 was considered as statistical significant.

Results
This study was conducted upon 40 eyes of 40 patients who had visual significant cataract and primary open angle glaucoma.the patient fulfilled the inclusion criteria. the cases were dividing randomly into two groups. Group I :20 patients (14 male 70% and 6 female 30%) who underwent one site phacotrabeculectomy. Group II: 20 patients (12 male 60% and 8 female 40%), who underwent two-site phacotrabeculectomy. There was no statistically significant difference between the two groups as regard to age, sex , preoperative IOP, and number o fpreoperative antiglaucomaus medications and preoperative BCVA because p value is more than 0.05 as shown in Table 1 . There was statistically significant reduction in the intraocular pressure as mean IOP was reduced from 22.05 mmHg (SD 1.6) preoperatively to 14.2 mmHg (SD 1.06) postoperatively in the one-site group (p 0.00008) and from 22.4 mmHg (SD 1.8) preoperatively to 13.5 mmHg (SD 1.19) postoperatively in the two-site group (p 0.00008 ). So the two-site group had more reduction in IOP than one-site group , but the difference between them was not statistically significant (p 0.074).
The number of patient. Figure 1:-the pre-and postoperative intraocular pressure (IOP) for each eye, in the one-site group.
The number of patients. Figure 2:-The pre-and postoperative intraocular pressure (IOP) for each eye, in the two-site group.
As regard to antiglaucomatus medications , their mean was reduced from 2.6 (0.5) preoperatively to 0.3 (SD 0.47), postoperatively in the one site group group (p 0.00008) and from 2.7( 0.4) preoperatively to The 0.25 (SD 0.44) postoperatively in the two-site group (p 0.00008).So there is statistically significant reduction of antiglaucomatus medications in both groups ( p < 0.05). Although of the two-site group needed less antiglaucomatus medications than one site group group.but there was no statistically significant difference between them (p 0.94).  4 5 6 7 8 9 10 11 12 13 14 15 16 17 18   AS regard to postoperative best-corrected visual acuity (BCVA),there was improvement from 0.82 (SD 0.18) logMAR preoperatively to 0.15 (SD 0.11) logMAR postoperatively in the one site group (P 0.000088),and from 0.83 (SD 0.18) ) logMAR preoperatively to 0.14 (SD 0.11) logMAR postoperatively in the two site group (P 0.000088).Although the two site had better (BCVA) than the one site, but the difference was not statistically significant (P 0.97).  AS regard to postoperative astigmatism , the one site group had 0.4D (SD .36) while two site group had 0.15D (SD 0.19). So two site group had less induced astigmatism than one site group that was statistically significant (P 0.01).
There was no intraoperative or postoperative complication apart from one case of shallow anterior chamber that is controlled medically in one site group.

Discussion:-
The incidence of presence of cataract together with glaucoma is increasing as the life expectancy increases. Challenge of managing of coexisting cataract and glaucoma becomes more frequent. the cataract surgery alone can be done when the patient had significant cataract and early mild glaucoma controlled with only one medication. 11 the main indication of combined surgery is the patient had significant cataract and uncontrolled glaucoma or poor compliance. 12 The advantages of phacotrabeculectomy are early visual rehabilitation ,adequate long term controll of IOP and save the time and effort. 13 The decision is to perform combined phacotrabeculectomy through one or two sites.The two-site approach has advantage of less manipulation of the conjunctiva and extraction of cataract easily while one -site approach has advantage of less number of incisions. 14 The main concern in this study is to compare one-site versus two-site fornix-based phacotrabeculectomy without the use of antimetabolites in reducing IOP and the need of antiglaucoma medications .The result of this study is that the two-site approach is more effective in reducing IOP and the need for supplemental antiglaucoma medications than one -site approach ,but the difference is not statistical significant (P >0.05). And both surgical strategies succeeded in decreasing IOP and the need for antiglaucoma medications and their effects were statistical significant (P <0.05).
the one-site technique was less effective and required the more medications to obtain the same level of IOP as the two-site technique. This can be due to increased manipulation of the conjunctival and scleral flaps inducig fibrosis. 15 In addation to the local increase in temperature at the trabeculectomy site and at the scleral flap caused by the production of heat by the phacoemulsification probe is another possible factor contributing to decrease the efficacy of the one-site technique.
Previous studies supported that there was no statistically significant difference in postoperative IOP between oneand two-site phacotrabeculectomy [16][17][18] , although a recent meta-analysis of randomized controlled trials concluded that the two-site phacotrabeculectomy is superior to one-site phacotrabeculectomy in reducing IOP. 19 Two studies comparing one-versus two-site phacotrabeculectomy found that the one-site group needed significantly more medications than the two-site group. 13,20 In contrast, two other prospective studies and one retrospective study suggested that there was no statistical difference in the postoperative mean number of glaucoma medications in oneversus two-site phacotrabeculectom. 14,21,2 There was significant improvement in the postoperative best-corrected visual acuity (BCVA) in both one site and two groups (P >0.05).Although two site group had better BCVA than one site group , but the difference was not statistically significant (P 0.97). two site group had less induced astigmatism than one site group that was statistically significant (P 0.01).
studies founded that a scleral tunnel produces less astigmatism compared to a clear corneal incision in cataract surgery. 23 Other authors founded that an incision at the 12 o'clock position produces more astigmatism compared to a temporal incision. 24 So less astigmatic effect of the scleral tunnel was outweighed by the astigmatism-inducing effect of an incision at the 12 o'clock position in addation to more manipulations through the scleral tunnel can lead to that one site group has more induced astigmatism than one site group . There was no intraoperative or postoperative complication apart from one case of shallow anterior chamber that is controlled medically in one site group.