Efficacy of Punch Trabeculectomy as an IOP lowering modality in various type of Primary Glaucoma. Let me acknowledge the help rendered by my wife Dr. Sandhya, assistants, Dr. Shubhangi and Miss Dhruti in going through the case records and scrutinizing the perimetry charts. Special thanks to Mr. Mayank Rao for the biostatistical help with SPSS software.
IOP is the only modifiable risk factor in glaucoma management. Relation between the two is well documented by Vogel and Gazzard in British Journal of Ophthalmology. Aim of glaucoma therapy, till today, is to establish a target IOP as mentioned by Popovi and to maintain the diurnal pressure below the target to reduce the field loss and improve optic nerve circulation as documented by Anders in Archieves.
Several expensive medications with tall claims were compared with a standardized punch trabeculectomy technique applied to various types of primary glaucoma.
Case records of 46 eyes of 41 patients of primary glaucoma, who after a fair trial of medical treatment had to eventually undergo Punch trabeculectomy without antimetabolites as a primary procedure were studied. They were classified from their Gonioscopic findings as Primary Open angle (POAG), Primary Narrow Angle (PNAG) and Acute congestive glaucoma.
All cases underwent complete ocular examination including Gonioscopy, Applanation Tonometry and Autoperimetry.
Initial Target was set at 20 to 40% reduction from baseline IOP as per the Glaucoma clinical trial guidelines shown by Sonal Wadhwa in her publication.
This was Dynamically modified by scrutinizing the follow up fields applying the visual field scoring technique recommended by Brenda Gillespie in her publication. When the fields showed deterioration, the target was further reduced by deducting the mean deviation from the field report, as recommended by Dr. Curt Hartleben
Slide 12. Results: Mean pretreatment IOP 22 to 51 mm Hg with mean at 32.4 and standard deviation of 7.21. 13 eyes each in POAG and PNAG group had baseline IOP less than 30. Target IOP raged from 5mm to 19mm Hg with mean at 12,3 and standard deviation of 3.25. This amounted to 60.2% mean reduction with standard deviation of 12.31.
Medical management to meet the goal,
Apart from uncontrolled IOP and unabated field loss in spite of maximum tolerated medical therapy, other indications to consider filtration surgery were, non compliance or intolerance to multiple drugs and associated significant cataract. 10 eyes underwent only trabeculectomy and 26 were combined with phacoemulsification using a separate temporal clear corneal incision as a primary procedure.
Slide 10 Fornix based 6×9mm conjunctival flap made in upper nasal quadrant as per the reference of A. K. Negi and Vernon. Triangular scleral partial thickness flap designed with 4mm base and height 3mm. After a separate clear corneal paracentesis away from filtration site, the anterior chamber opened at the base of the triangular flap and 0.75mm scleral window removed with Kelly’s punch. A peripheral button hole iridectomy was made and scleral flap closed with two side 10/0 sutures and one apical suture. Conjunctiva was closed by two interrupted 10/0 sutures taken with scleral bite first to achieve buried knots. When combined with cataract surgery, a temporal clear corneal incision was taken for phacoemulsification Post Surgery medications: Steroid with antibiotic drops qid for one month. Atropine drops tid for first 7 days.
Slide 11. . Surgery post op Follow ups were done on 1st, 7th 15th and 30th days and every month for minimum 6 months thereafter. Slit lamp examination, non contact applanation tonometry, BCVA and retinal examination done at each visit for first month to identify complications like bleb leak, infection, choroidal effusions, retinal hemorrhages, edema and IOP. Bleb formation was checked on slit lamp by gently applying pressure on temporal sclera during initial month. Conjunctival sutures were removed if required after 2 months post op. Post op follow up ranged from 6 months to 2 years with mean 11 months.
Slide 21 Comparison between trabeculectomy done alone and trabeculectomy With temporal clear corneal phaco showed the mean IOP fqall in trab alone was 66.13% against 56.28% in trab+phaco group. Ref. Lochhead J BJO 2003;87(7)850-2 compared separate trab incision with phacotrab single incision and found separate incisions better for IOP reduction.
Slide 22 Surgery alone was completely successful in reaching the target IOP in 35 out of 46 eyes (76%). Post surgical topical medication became necessary in 11 out of 46 eyes to maintain the target IOP. 7 reached the target with single drug post op to achieve qualified success (15.2%). 4 eyes out of 46 continued to have IOP higher than the set target to be labeled as failures (8.6%).
Efficacy of Punch Trabeculectomy
Efficacy of Punch Trabeculectomy in different types of Glaucoma Dr. Anand Sudhalkar Baroda. Acknowledgements: Dr. Sandhya Dr. Shubhangi Ms. Dhruti Mr. Mayank Rao
Introduction: <ul><li>IOP the only Modifiable Risk Factor in glaucoma management </li></ul><ul><li>Maintaining IOP below the Target reduces field loss and improves optic nerve circulation. </li></ul><ul><li>R. Vogel et al. Association between intraocular pressure and loss of visual field in chronic simple glaucoma BJO 1983; vol 67, 220-227, </li></ul><ul><li>G. Gazzard Intraocular pressure and visual field loss in primary angle closure and primary open angle glaucomas BJO 2003; 87:720-725 </li></ul><ul><li>Popovi. Target intraocular pressure in the management of glaucoma. Coll Antropol 2005; 29 Suppl 1:149-51. </li></ul><ul><li>Anders Heijl. Reduction of Intraocular Pressure and Glaucoma Progression, Arch Ophthalmol. 2002; 120:1268-1279. </li></ul>
AIM:To compare the IOP lowering efficacy M edical treatment v/s Standardized Punch trabeculectomy surgery without anti-metabolites. <ul><li>Vernon: Medium to long term intraocular pressure control following small flap trabeculectomy (microtrabeculectomy) BJO 1998;82:1383-1386 </li></ul><ul><li>Stalmans, Gillis: Safe trabeculectomy technique: long term outcome . BJO 2006; 90(1):44-7 </li></ul>
Material: <ul><li>46 eyes of 41 patients subjected to Punch Trab. after Trial of medical treatment. </li></ul><ul><li>POAG – 22 </li></ul><ul><li>PNAG – 19 </li></ul><ul><li>ACUTE CONGESTIVE – 5. </li></ul>
Methods: <ul><li>Complete eye examination </li></ul><ul><li>Gonioscopy </li></ul><ul><li>Autoperimetry (Octopus) </li></ul><ul><li>Mean Baseline IOP: with Non Contact Applanation tonometry at 8 am, 3 pm and 8 pm </li></ul>
Target IOP calculations <ul><li>Initial Target IOP: 20 to 40% reduction from Baseline IOP </li></ul><ul><li>Sonal Wadhwa, Comprehensive ophthalmological update volume 6, in November 2005 . </li></ul>
Dynamic Resetting Target by quantifying Fields <ul><li>The VF score is calculated as follows: First, neighboring points are defined as those adjacent to a given point, whether on a side or a corner. Each of the 52 points in the field is individually graded. A point is called defective if its probability is 0.05 or less, and it has at least two neighboring points with probabilities of 0.05 or less in the same vertical hemifield (superior or inferior). A weight is assigned depending on the minimum depth of the defect at the given point and the two most defective neighboring points. A minimum defect of 0.05, 0.02, 0.01, and 0.005 is given a weight of 1, 2, 3, and 4, respectively. A point without two neighboring points all depressed to at least P ≤ 0.05 is given a weight of zero. For example, a point at P ≤ 0.01 with only two neighboring points of defect, both at P ≤ 0.05, would receive a weight of 1. The weights for all 52 points in the field are summed, resulting in a value between 0 and 208 (52 x 4). The sum is then scaled to a range of 0 to 20 (dividing the sum by 10.4), to yield values in the same range as the VF score previously developed by the Advanced Glaucoma Intervention Study (AGIS). 1 The resultant score is a nearly continuous measure of VF loss. </li></ul><ul><li>Further reduced by deducting the mean deviation from the field report. </li></ul><ul><li>(Dr. Curt Hartleben) </li></ul>Brenda W. Gillespie (Investigative Ophthalmology and Visual Science. 2003; 44:2613-2620.)
Medical Management Protocol: <ul><li>Monotherapy: Baseline IOP < 30mm Hg (28 eyes): Beta Blockers or Alpha 2 agonist </li></ul><ul><li>Combination therapy : IOP > 30 mm Hg (18 eyes): + Latanoprost in POAG and + Pilocar 2% or Dorzolamide in PNAG. </li></ul><ul><li>Maximum Medical Therapy (all cases):+ Oral tab. Acetazolamide and + I.V. Inj Mannitol 20% </li></ul>
Duration of Medical Treatment Trial <ul><li>POAG: 3 months to 2 Years </li></ul><ul><li>PNAG: 2 months to 1 year </li></ul><ul><li>Acute Glaucoma: 2 to 7 days </li></ul>
Surgery <ul><li>Only Punch Trabeculectomy: 9 eyes </li></ul><ul><li>Punch Trab. With Phaco: 36 eyes </li></ul>
Surgical Technique: Trab+Phaco <ul><li>Upper nasal site(A. K. Negi and Vernon) </li></ul><ul><li>Fornix based conj. Flap </li></ul><ul><li>Triangular scleral flap upto clear cornea </li></ul><ul><li>Temporal Phaco incision </li></ul><ul><li>Complete Phaco surgery </li></ul><ul><li>Extend the tunnel into clear cornea </li></ul><ul><li>Kelly’s Punch </li></ul><ul><li>Iridectomy </li></ul><ul><li>Closure </li></ul>
Surgery: post op follow up: (Mean 13 months) <ul><li>Bleb Enhancement by Pressure on globe </li></ul>
Post OP Complications <ul><li>Bleb Related: NIL </li></ul><ul><li>Endophthalmitis: NIL </li></ul><ul><li>Hyphema : 1. in POAG Group </li></ul><ul><li>Choroidal Effusion : 2, one each in POAG and Acute narrow angle glaucoma patients. </li></ul><ul><li>All resolved after conservative management. </li></ul><ul><li>Post Trab. Cataract formation NIL in 9 eyes followed up 12 months. </li></ul>
Post Op Success Analysis: <ul><li>Complete: 35/46 eyes (76.08%) </li></ul><ul><li>Qualified: 7/46 eyes (15.2%) </li></ul><ul><li>Failure: 4/46 eyes (8.62%). </li></ul>91.28%
Paired Sample “t” Test to compare Target IOP with the IOP reduction in various groups:
Conclusion: <ul><li>Consistent & substantial (>50%) lowering of IOP is obtained only after surgical intervention. </li></ul><ul><li>A standardized surgical technique assures the safety and consistency. </li></ul><ul><li>The cost of life-long medication and compliance needs special consideration when prescribing topical medications. </li></ul>