Ординатура / Офтальмология / Английские материалы / Step by Step Minimally Invasive Glaucoma Surgery_Garg, Melamed, Bovet, Pajic, Carassa, Dada_2006

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13.Feltgen N, Mueller H, Ott B, Frenz M, Funk J. Combined endoscopic erbium:YAG laser goniopuncture and cataract surgery. J Cataract Refract Surg 2003;29(11):2155-62.

14.Feltgen N, Mueller H, Ott B, Frenz M, Funk J. Endoscopically controlled erbium:YAG goniopuncture versus trabeculectomy: Effect on intraocular pressure in combination with cataract surgery. Graefes Arch Clin Exp Ophthalmol 2003;241(2):94-100.

15.Philippin H, Wilmsmeyer S, Feltgen N, Ness T, Funk J. Combined cataract and glaucoma surgery: Endoscopecontrolled erbium:YAG-laser goniotomy versus trabeculectomy. Graefes Arch Clin Exp Ophthalmol 2005.

16.Walker R, Specht H. Theoretical and physical aspects of excimer laser trabeculotomy (ELT) ab-interno with the AIDA laser operating at 308 nm. Biomedizinische Technik 2002;47(5):106-10.

17.Berlin MS. Perspectives on new laser techniques in managing glaucoma. Ophthalmology Clinics of North America 1995;8(2):341-63.

18.Berlin MS. We need a trabecular meshwork procedure that works. American Glaucoma Society Annual Meeting, San Jose 2002.

19.Berlin MS. ELT Eximer Laser Trabeculostomy: Update 2003. ASCRS 2003.

20.Berlin MS, Funk J, Pache M, Wilmsmeyer S, Giers U, Kleineberg L, et al. Excimer Laser Trabeculostomy. A new, minimally invasive surgical procedure for the treatment of open-angle glaucoma. Glaucoma Today 2004;2-6.

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INTRODUCTION

The ongoing devote on recent developments in glaucoma surgery reflects that an ideal solution is not available which would promise long-term IOP reduction and eliminate the necessity of supplementary pressurereducing medication at low complication rates. Trabeculectomy, first described in the sixties,3,9,30 is probably the most widespread approach in glaucoma surgery presently. The intention of trabeculectomy is to bypass the resistance of trabecular meshwork by channelling aqueous humor directly to the Schlemm’s canal. In literature the success rate of trabeculectomy

ranges between 32-96 percent.1,4,9,12,14,16-18,21-23,30,32-35 On the

other hand, postoperative complications like hypotony and choroidal detachment are reported up to 24 percent.6 Variation of success rates may be explained by different criteria of surgical indications, selection of cases, various diagnoses, the various degrees of surgical experience and variations in postoperative medical treatment. Failure of pressure regulations is associated with the assence of a filtering bleb and depends on the duration of follow-up involved. It has become evident that successful reduction in IOP following trabeculectomy is clearly related to the presence of a filtering bleb.26

The more recent method of non-penetrating deep sclerectomy, was first described by Fjodorov in the eighties.8 This techniques tries to achieves an improved uveoscleral outflow and therefore is not depending on the presence of a filtering bleb. Koslov13 expanded this method by introducing a collagen implant. Literature on nonpenetrating deep sclerectomy indicates a success rate of 58 to 74 percent without collagen implant and 74 to 90 percent with collagen implantation.5,24

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In 1976, Benedikt2 described that the exposure of the ciliary body (i.e. a form of penetrating sclerectomy) was leading to successful long-term IOP regulation in 27 of 38 cases involving hemorrhagic, aphakic and irreversible angle-closure glaucoma after initially failed filtering surgery. This technique was the basis for later development of perforating deep sclerectomy, a method which has been used since 1985 was described previously20 as “sclerothalamectomy”). Bypassing of the trabecular meshwork is an alternative for aqueous humour outflow from the anterior chamber to the Schlemm canal. It is the principal mechanism for non-penetrating glaucoma surgery, in particular, for deep sclerectomy and viscocanalostomy. These surgical procedures provide effective IOP reduction as well as the elimination of typical filtration bleb complications.7,15,31 So far clinical application of these procedures has been limited by technical difficulties to perform this kind of surgery and a poor predictability of pressure reduction.

The concept of trabecular meshwork bypass as a surgical principle for glaucoma treatment evolved from the discovery that pathologic outflow resistance is caused primarily by the juxtacanicular conjunctive tissue of the trabecular meshwork and, in particular, by the inner wall of the Schlemm canal.10,11 A further publication in this area indicates that 35 percent of the outflow resistance arises distally to the inner wall of the Schlemm canal.25

Spiegel et al29 have described a new surgical technique involving the use of an implanted tube, the so-called trabecular meshwork bypass tube shunt, which should provide a direct connection between Schlemm canal and the anterior chamber. This surgical technique avoids technical difficulties of non-penetrating deep sclerectomy, especially the delicate microperforation of the trabecular

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meshwork in order to ensure the permeability of the descemet membrane. Furthermore, these techniques avoid the disadvantages of filtration blebs.

All surgical procedures for glaucoma involving the creation of external access may be complicated by the risk of fibroblast proliferation and failure of filtration. The novel procedure published offers a chance to avoid some of the above-mentioned disadvantages. We refer to this technique as sclerothalamotomy ab interno.19

PATIENTS AND METHODS

Before beginning the clinical study phase, the tips used for the STT ab interno procedure were developed using a large number of pigs’ eyes. The high-frequency diathermic technique was already very well known in the application for capsulorhexis in cataract surgery. It was important to create a design for optimal application of the STT probe in the iridocorneal angle and to evaluate the characteristic of the achieved deep sclerotomy. By virtue of this results the STT ab interno probe development as describe below.

53 sclerothalamotomies ab interno in 53 patients were carried out in primary open-angle glaucoma between 1 April 2002 and 31 July 2002. Main inclusion criterion into this study was an insufficient response to medical treatment of IOP. Data was documented according to a prospective study protocol. Mean age of patients was 72.3±12.3 years (range: 15-92 years) (Fig. 8.1). 17 patients (32%) were female, 36 patients (68%) male. In 25 cases (47.4%) the right eye in 28 cases (52.6%) the left eye was treated. There was no patient who received bilateral surgery. Snellen visual acuity was 0.7±0.3 (range 0.1 to 1.0) preoperatively. In 5 cases a moderate cataract was observed which didn’t have influence on the visual acuity.

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Fig. 8.1: Mean age

A complete ophthalmologic status check was carried out in each patient prior to surgery including: uncorrected and best corrected visual acuity, IOP applanation tonometry, biomicroscopy of anterior segment, funduscopy (in particular, stereoscopic evaluation of the optic nerve head) and computerized visual field testing (Octopus 101, program G2).

Complete ophthalmologic follow-up examinations were carried out postoperatively at day 1, 2, 3 and 4, after 1, 2 and 4 weeks, and 2, 3, 6, 12, 15, 18, 21, 24, 27, 30, 33 and 36 months.

In a pilot study with at least of 24 months follow-up, 5 patients with therapy-resistant juvenile glaucoma were treated.