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 Table of Contents  
INNOVATION
Year : 2017  |  Volume : 29  |  Issue : 1  |  Page : 41-45

Aurolab aqueous drainage implant: My surgical technique


Department Of Glaucoma Services, Aravind Eye Hospital and Postgraduate Institute of Opthalmology, Coimbatore, Tamil Nadu, India

Date of Web Publication19-Jun-2017

Correspondence Address:
S Archana
Aravind Eye Hospital, Avinashi Road, Coimbatore - 641 014, Tamil Nadu
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/kjo.kjo_56_17

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  Abstract 


Aurolab aqueous drainage implant is a nonvalved tube implant used to treat refractory glaucoma. Although implanting the device could be surgically more demanding than certain other drainage devices, the author aims to describe the techniques which enable him to perform the surgery safely and efficiently.

Keywords: Aurolab aqueous drainage implant, scleral sleeve, surgical technique


How to cite this article:
Archana S, Premanand C, Raman GV. Aurolab aqueous drainage implant: My surgical technique. Kerala J Ophthalmol 2017;29:41-5

How to cite this URL:
Archana S, Premanand C, Raman GV. Aurolab aqueous drainage implant: My surgical technique. Kerala J Ophthalmol [serial online] 2017 [cited 2019 Jan 21];29:41-5. Available from: http://www.kjophthal.com/text.asp?2017/29/1/41/208492


  Introduction Top


Aurolab aqueous drainage implant (AADI) is a nonvalved device useful in refractory glaucoma to achieve low intraocular pressure (IOP) when other methods have failed. It is made of NuSil permanent implant silicone elastomer which has passed tissue culture cytotoxicity testing. Its surface area is 350 mm2; its lateral wings are designed to be positioned under the rectus muscle. It has fixation holes to facilitate anchoring of the end plate about 10 mm posterior to the limbus. The device has been commercially available in India since 2013 and is similar to the Baerveldt glaucoma implant in design and function. Dr. Paul Palmberg was instrumental in the development of the AADI device.

There are various techniques of performing the glaucoma valve surgery, and over a period I have minimized the steps of the surgery in a manner which helps me do the procedure safely, efficiently and in very little time.


  Conjunctival Dissection Top


Adequate exposure is ensured by passing a 7-0 polyglactin suture through the peripheral cornea at around 12'0 clock position. Since the device implantation is invariably the second surgery for the eye in question, I prefer a limbus-based flap. The main concern is limbal stem cell deficiency which may occur in predisposed eyes with recurrent dissection of the conjunctiva at the limbus.[1] The conjunctival incision is made about 8–9 mm away from the limbus in the superotemporal site approximately between the lateral and superior rectus muscles [Figure 1] and [Figure 2].
Figure 1: Marking the conjunctiva 8 mm behind the limbus to fashion a limbus based conjunctival flap

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Figure 2: Relaxing cuts given in the conjunctiva after conjunctival dissection for adequate exposure of the surgical field

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  Securing the Plate to the Sclera Top


After the conjunctival incision, the bare sclera is approached between the superior rectus and the lateral rectus. Novice surgeons attempting implant surgery usually underestimate the extent of the fan of the insertion of the tendon of the lateral and superior rectus muscles, and in their eagerness to hook the muscle may split the muscle fibers and induce trauma, which may later manifest as diplopia.[2] Another mistake surgeons make is to isolate muscle belly from all sides (e.g., in case of superior rectus from the temporal and nasal border), which is not warranted since one side exposure allows the implant to be slipped beneath the temporal part of superior rectus and superior aspect of the lateral rectus [Figure 3] and [Figure 4].
Figure 3: Two muscle hooks under the superior rectus muscle after isolation and dissection of the lateral border of the muscle (right eye of the patient). Note the medial border of the muscle is barely dissected or exposed

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Figure 4: Two muscle hooks under the dissected lateral rectus muscle

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  Preparation of the Implant Top


The tube of the implant is tested for patency. Then the tube is ligated with 7-0 vicryl suture. The tube occlusion is tested using a hydrating cannula (28-gauge) and serrated forceps[Figure 5],[Figure 6],[Figure 7],[Figure 8].
Figure 5: The patency of the tube is tested

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Figure 6: The tube is completely occluded by ligature with 7-0 polyglactin suture close to the plate

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Figure 7: The plate is tucked underneath the superior rectus muscle

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Figure 8: The plate being tucked underneath the lateral rectus muscle

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The plate is anchored using nylon (8-0/9-0) sutures. I prefer to use the 9-0 nylon suture and make the needle pass through the sclera out through the eyelet of the implant on the temporal aspect and then take the same needle through the nasal eyelet of the implant (without cutting the suture) and out through the sclera. After assessing the length of suture required to tie the implant, the suture between the eyelets is cut and the sutures are tied, anchoring the plate to the sclera. By this method, the plate is secured about 10–12 mm away from the limbus quite effortlessly. This leaves sufficient sclera ahead of the plate for dissecting the scleral tunnel through which the tube is placed into the anterior chamber (AC).


  Scleral Tunnel Top


I have avoided using scleral patch grafts [3] and instead use the sclera of the patient to create a scleral tunnel.[4],[5],[6] The tunnel will start about 3–4 mm in front of the plate and extend about 4 mm short of the limbus. From 4 mm away from the limbus, a needle (23-gauge) track is made into the AC almost in the same plane as the scleral tunnel. One could also use a donor patch graft (corneal/scleral) to cover the tube at the point of entry into the sclera [Figure 9],[Figure 10],[Figure 11],[Figure 12].
Figure 9: Usage of corneal patch graft to cover the exposed part of tube before is anterior chamber entry

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Figure 10: The scleral groove being created with a Bard Parker knife

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Figure 11: The scleral tunnel dissected by a 23G needle

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Figure 12: The tube is made to pass through the scleral tunnel and into the anterior chamber

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The tip of the intact tube is first cut with bevel up fashion, and an attempt is made to insert the tube into the AC. This is done because most of the eyes which undergo tube shunt surgeries have distorted limbal anatomy. Hence, it is wise to confirm entry of the tube before finally trimming the tube to the desired length. Once a comfortable entry is confirmed the tube is trimmed to requisite length and is inserted into the AC [Figure 13].
Figure 13: Trimming the end of the tube with bevel up after confirming its entry tract and assessing its optimal length

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Any tube track which is made and not used should be secured using an infiniti suture to prevent leak. In case of shallowing of the AC during insertion or accidental iris touch a paracentesis can be made to reform the chamber.

The tube is secured using nylon (9-0) sutures close to the plate. The tube is also secured to the sclera at the point of entry into the scleral tunnel. The incision on the sclera 4 mm behind the limbus is also secured with (9-0) nylon using an infiniti suture. The aim is to prevent wriggling of the tube and subsequent extrusion from the AC. Venting slits can be made if immediate IOP control is warranted. They are made distal to the ligature with 1–2 small punctures with a spatulated (10-0 nylon) needle.


  Closure Top


The conjunctiva is closed in running fashion using a polyglactin (8-0) suture, without tension. In many situations, the AC is not entered, and a subconjunctival injection of a combination of steroid and antibiotic is administered [Figure 14].
Figure 14: Conjunctival closure with polyglactin (8-0) running suture

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We have also used AADI implant for glaucoma following vitreo-retinal surgeries. In eyes which have undergone complete vitrectomy, it is wise to implant the tube in the vitreous cavity.[7],[8] All other steps of the surgery are performed as mentioned above. Once the plate is secured and the tube ligated, a 23-gauge needle is used to make the stab incision into the vitreous cavity 5 mm–5.5 mm away from the limbus. The stab incision using the 23-gauge needle is made in a rotating fashion and while exiting the needle is used to slightly extend the opening so that the tube can be easily slid into the sclerostomy. The tube is then trimmed and then slid into the sclerostomy wound. Approximately, 5–6 mm length of the tube is left in situ. A nylon 10-0 suture is used in a purse string fashion to secure the tube to the sclera. A sclera or corneal patch graft is used to cover the entry of the tube into the sclera, and it is anchored with nylon 10-0 sutures. The remaining length of the tube is anchored to the sclera with 10-0 nylon sutures [Figure 15] and [Figure 16].
Figure 15: Tube passed into the vitreous cavity through a stab incision made with a 23-gauge needle 5 mm from the limbus

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Figure 16: Tube in vitreous cavity secured to the sclera with 10-0 nylon purse string suture

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  Advantages of the Aurolab Aqueous Drainage Implant Devise Top


Due to the larger surface area it provides achieves lower IOP in the long-term as compared to valved devices. There is less chance of bleb encapsulation as it is not exposed to the inflammatory mediators from the AC until the tube opens up, which is typically after 4–6 weeks. Hence, there is no typical hypertensive phase [9] as in the case of valved devices, although during the initial few weeks there is a bout of raised IOP till the ligature gives way. During this period, the patient has to be on maximal medical therapy.

The most significant advantage is the cost. It is much more economical compared to the other commonly used devices like the Baerveldt or the Ahmed valve without a compromise on the efficacy.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

1.
Dua HS, Saini JS, Azuara-Blanco A, Gupta P. Limbal stem cell deficiency: Concept, aetiology, clinical presentation, diagnosis and management. Indian J Ophthalmol 2000;48:83-92.  Back to cited text no. 1
[PUBMED]  [Full text]  
2.
Rauscher FM, Gedde SJ, Schiffman JC, Feuer WJ, Barton K, Lee RK; Tube Versus Trabeculectomy Study Group. Motility disturbances in the tube versus trabeculectomy study during the first year of follow-up. Am J Ophthalmol 2009;147:458-66.  Back to cited text no. 2
    
3.
Smith MF, Doyle JW, Ticrney JW Jr. A comparison of glaucoma drainage implant tube coverage. J Glaucoma 2002;11:143-7.  Back to cited text no. 3
    
4.
Kalamkar C, Radke N, Mukherjee A, Radke S. A new surgical technique of intra-scleral tube fixation in Ahmed glaucoma valve implantation: Scleral Sleeve Method. Saudi J Ophthalmol 2017. [Epub ahead of print].  Back to cited text no. 4
    
5.
Albis-Donado O, Gil-Carrasco F, Romero-Quijada R, Thomas R. Evaluation of Ahmed glaucoma valve implantation through a needle-generated scleral tunnel in Mexican children with glaucoma. Indian J Ophthalmol 2010;58:365-73.  Back to cited text no. 5
[PUBMED]  [Full text]  
6.
Ollila M, Falck A, Airaksinen PJ. Placing the Molteno implant in a long scleral tunnel to prevent postoperative tube exposure. Acta Ophthalmol Scand 2005;83:302-5.  Back to cited text no. 6
    
7.
de Guzman MH, Valencia A, Farinelli AC. Pars plana insertion of glaucoma drainage devices for refractory glaucoma. Clin Exp Ophthalmol 2006;34:102-7.  Back to cited text no. 7
    
8.
Sidoti PA, Mosny AY, Ritterband DC, Seedor JA. Pars plana tube insertion of glaucoma drainage implants and penetrating keratoplasty in patients with coexisting glaucoma and corneal disease. Ophthalmology 2001;108:1050-8.  Back to cited text no. 8
    
9.
Stein JD. Standard technique for implanting glaucoma drainage devices. In: Kahook MY, editor. Essentials of Glaucoma Surgery. 1st ed. New Jersey: Slack Inc.; 2002. p. 81-94.  Back to cited text no. 9
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10], [Figure 11], [Figure 12], [Figure 13], [Figure 14], [Figure 15], [Figure 16]



 

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  In this article
Abstract
Introduction
Conjunctival Dis...
Securing the Pla...
Preparation of t...
Scleral Tunnel
Closure
Advantages of th...
References
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