1. Efficacy of Punch Trabeculectomy in different types of Glaucoma Dr. Anand Sudhalkar Baroda. Acknowledgements: Dr. Sandhya Dr. Shubhangi Ms. Dhruti Mr. Mayank Rao
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%).