Ординатура / Офтальмология / Английские материалы / Step by Step Minimally Invasive Glaucoma Surgery_Garg, Melamed, Bovet, Pajic, Carassa, Dada_2006
.pdf
222 Step by Step Minimally Invasive Glaucoma Surgery
Fig. 12.18: Graph showing the percent of success of milling surgery and milling-phaco after 65 months, the percent of eyes that had to use topical treatment and eyes that had to go back to treatment as the target pressure was not reached
this technique does not require any specific accuracy in the dissection of the deep sclera.
2.To reduce the wound healing as a determinate factor for the IOP outcome as the diamond powder tip is available for more delicate maneuvers like removing debris, making the technique ideal and leaving an extremely smooth bed.
3.Offers less complications than deep sclerectomy and it prevents the “double-cut” sclera and hazards.
4.The economic coast of the drill.
5.Saves time as this technique has an easier approach to the trabeculo-descemetic membrane.
6.No need for the use of high expensive surgical set.
CONCLUSION
Milling trabecuoloplasty is an evolving technique for easy scalpel-free non-penetrating glaucoma surgery. The milling
Milling Trabeculoplasty 223 
surgery seems to be a promising technique for surgical management of POAG glaucoma. Milling trabeculoplasty is a fast, safe, effective technique to perform nonpenetrating glaucoma surgery low coast and simple instruments. Milling trabeculoplasty is a potential alternative to deep sclerectomy providing comparable results to conventional deep sclerectomy mainly the low level of IOP together with minimal intraand postoperative complications.
REFERENCES
1.Carassa RG. Non-penetrating surgery. In: Weinreb RN, Kitazawa Y, Krieglstein GK (Eds): Glaucoma in the 21st Century. Philadelphia: Harcourt Health Communications, 2000;249-56.
2.Watson PG, Grierson I. Early trabeculectomy in the treatment of chronic open-angle glaucoma in relation to histological changes. In Zimmerman TJ, Monica ML (Eds): Controversies in Glaucoma. Int Ophthalmol Clin 1984;24: 13-32.
3.Zimmerman TJ, Kooner KS, Ford VJ, et al. Trabeculectomy vs. nonpenetrating trabeculectomy: a retrospective study of two procedures in phakic patients with glaucoma. Ophthalmic Surg 1984;15:734-40.
4.Mermoud A. La sclerectomie profonde. Technique chirurgicale. [Deep sclerectomy: surgical technique]. J-Fr- Ophthalmol 1999;22:781-6.
5.Bas JM, Goethals MJ. Non-penetrating deep sclerectomy preliminary results. Bull-Soc-Belge-Ophthalmol. 1999;272: 55-9.
6.Carassa RG, Bettin-P, Fiori-M, Brancato-R. Viscocanalostomy: a pilot study. Eur J Ophthalmol 1998;8:57-61.
7.Hara T; Hara T. Deep sclerectomy with trabeculotomy ab externo: one-stage procedure Ophthalmic Surg 1989;20: 406-9.
224 Step by Step Minimally Invasive Glaucoma Surgery
8.Demailly P, Lavat P, Kretz G, Jeanteur-Lunel-MN. Nonpenetrating deep sclerectomy (NPDS) with or without collagen device (CD) in primary open-angle glaucoma: middle-term retrospective study. Int-Ophthalmol 1996- 97;20:131-40.
9.Demailly P, Jeanteur-Lunel MN, Berkani M, Ecoffet-M, Kopel-J, Kretz-G, Lavat-P. La sclerectomie profonde nonperforante associee a la pose d’un implant de collagene dans le glaucome primitif a angle ouvert. Resultats retrospectifs a moyen terme. [(Non-penetrating deep sclerectomy combined with a collagen implant in primary open-angle glaucoma. Medium-term retrospective results). J.- Fr.- Ophtalmol 1996;19:659-66.
10.Chiou AG, Mermoud A, Hediguer SE, Schnyder CC, Faggioni R. Ultrasound biomicroscopy of eyes undergoing deep sclerectomy with collagen implant. Br-J-Ophthalmol 1996;80:541-4.
11.Tixier J, Dureau P, Becquet F, Dufier JL. Sclerectomie profonde dans le glaucome congenital. Resultats preliminaries. [Deep sclerectomy in congenital glaucoma. Preliminary results).]. J-Fr-Ophtalmol 1999;22:545-8.
12.Rodriguez-Prats JL, Alio JL, Galal A. Milling trabeculoplasty for non-penetrating glaucoma surgery. J Cataract Refract Surg 2004;30:1507-16.
13.Goldsmith JA, Ahmed IK, Crandall AS. Non-penetrating glaucoma surgery. Ophthalmol Clin North Am 2005;18: 443-60.
14.Dahan E. Long-term results of deep sclerectomy with collagen implant. J Cataract Refract Surg. 2005;31:868-9.
226 Step by Step Minimally Invasive Glaucoma Surgery
INTRODUCTION
Surgery for primary open-angle glaucoma is usually a ‘last resort’ option. Today we exercise thisoption less frequently, thanks to better medications that have not only a pressure lowering effect but also neuro-protective properties. When there is a need for surgery, it implies that medical management alone is not sufficient in controlling the disease process. One would expect that the surgical procedure, therefore, would deliver the goods each time, every time, for keeps. Unfortunately, surgical outcomes do not always match the need of the hour. Glaucoma surgery is known to fail over a period and trabeculectomy, once the gold standard, is now known to stop draining as time progresses (Fig. 13.1). The chief culprit is fibrosis between the scleral bed and the flap that shuts down the drainage corridor.
Fig. 13.1: Trabeculectomy
Deep Sclerectomy with T-flux Implant 227 
NATURE’S DRAINAGE CHANNELS
Surgery for glaucoma is nothing but our attempt at duplicating nature’s process artificially. However, it does not always work out quite the way we intend it to. Let us, therefore, take a fresh look at nature’s drainage channels from the eye. Most of our focus these long years has been limited to structures within the anterior chamber, mainly the trabecular meshwork. We generally tend to ignore the fact that from the trabecular meshwork onward, fluid is gathered up by aqueous veins, which connect to the episcleral vasculature (Fig. 13.2). At no point is the aqueous allowed to flow naked and openly. However, during all our surgical procedures we do exactly that – let the aqueous drain out uncovered by a sheath. Have we, even for a moment, considered the deleterious effects of such an event? Do we pause to deliberate on a cause-and-effect relationship between a bare unsheathed drainage and fibrosis induced failure?
Fig. 13.2: Nature’s enclosed drainage channels
228 Step by Step Minimally Invasive Glaucoma Surgery
ENSURE SURGICAL SUCCESS
The only way to ensure continuous drainage is to mimic nature as closely as possible, i.e. by providing covered or sheathed outflow from the eye. An early attempt in this direction was made with the introduction of the Ahmed glaucoma valve (Fig. 13.3). It was, however, destined to fail, as it relied on the creation of an external drainage lake, which eventually filled up. Molteno designed an ‘extension’ lake by having two plates. This merely delayed the inevitable pressure equalization that resulted in ‘no-flow’.
While the concept of sheathed outflow was brilliant, the setting up of an artificial lake was flawed. I attempted to rectify this flaw by directing the aqueous outflow into the potential supra-choroidal space.
HISTORY OF THE PROCEDURE
In 2001, I used a non-valvular silicon shunt to carry fluid directly from the anterior chamber to the supra-choroidal space (Fig. 13.4A). This drainage device, in its initial avatar, consisted of a simple small-bore silicon tube that had sharp tapered ends. After creating a scleral flap, an opening was made into the supra-choroid 3-4 mm from the limbus. The
Fig. 13.3: Ahmed glaucoma valve
Deep Sclerectomy with T-flux Implant 229 
tube was anchored to the scleral bed by a 10-0 nylon suture and one end was introduced into the supra-choroid. It was then flushed with an insulin syringe containing Ringer’s, to open up the potential supra-choroidal space and ‘charge’ the device. This ‘charging’ served to remove any air pocket and permit a smooth capillary flow when this tube was made to puncture the anterior chamber next (Fig. 13.4B). Flap suture completed the procedure.
The procedure worked well in terms of IOP control over time. The only disadvantage was that one had to open the anterior chamber. Then came along deep sclerectomy.
DEEP SCLERECTOMY WITH T-FLUX IMPLANT
As the procedure is well documented, I shall not attempt to reinvent the wheel. I shall reiterate, however, that this procedure offers several advantages over trabeculectomy.
a.A proper and diligent technique ensures an adequate outflow.
b.There is an inherent safety in not opening the anterior chamber.
c.The T-flux implant, being a non-absorbable biocompatible acrylic polymer, helps to maintain a permanent intra-scleral space (Fig. 13.5A). This is achieved by anchoring it to the scleral bed with a single suture (Fig. 13.5B).
d.It stabilizes the trabeculo-Descemet’s membrane and in case of micro punctures and prevents iris herniation.
THE FLIP SIDE
There is no denying the fact that deep sclerectomy is technically difficult. It has a steep learning curve. In the initial stages one often lands up converting to conventional trabeculectomy. It is no secret that this surgery places a
230 Step by Step Minimally Invasive Glaucoma Surgery
Figs 13.4A and B: Non-valvular shunt
Deep Sclerectomy with T-flux Implant 231 
Fig. 13.5A: T-flux
Fig. 13.5B: T-flux in scleral bed