References |
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References
Hogan MJ, Alvaredo JA, Weddell E (1971) Histology of the human eye. WB Saunders Company, Philadelphia, p 612
Lemley CA, Han DP (2007) An age-based method for planning sclerotomy placement during paediatric vitrectomy: a 12-year experience. Trans Am Ophthalmol Soc 105:86–89
Conventional Vitrectomy |
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with 3-Port Trocar Setup |
In this chapter, the surgeries for particular indications and with increasing levels of complexity are explained in detail. The surgeries are performed in monomanual technique. Silicone oil removal and vitreous haemorrhage without complex retinal diseases are ideal procedures for beginners, in particular in pseudophakic patients. In silicone oil removal, you learn to handle the trocars, focus the retina with the BIOM and understand the basic functions of the vitrectomy machine. In vitreous haemorrhage, you work with the vitreous cutter and learn to remove the vitreous base. Macular surgery is more advanced. The major steps to master here are the induction of a PVD and an atraumatic removal of the membrane.
5.1Silicone Oil, Densiron 68® and Oxane Hd® Removal
DVD
Video 5 Silicone oil removal
Traditionally, removal of silicone oil has been the first procedure to be performed independently when you make your first steps into the field of vitreoretinal surgery. This is because, in most cases, no major intraocular manipulations are performed, but a ‘proper’ 3-port setup is required and can be practised. In addition, most patients will be pseudophakic, so you do not have to fear a lens touch. And finally, this procedure can be rather boring for advanced surgeons, so they are more than willing to let beginners do these cases. The result is that the importance and the difficulty of the procedure are often underestimated. Silicone oil removal is an ideal opportunity to learn and to deal with the trocar cannulas and get a feeling for the posterior segment of the eye. We always perform silicone oil removal with the BIOM because we remove emulsified oil bubbles through a fluid–air exchange, and perform additional intraocular manipulations if necessary.
U. Spandau, H. Heimann, Practical Handbook for Small-Gauge Vitrectomy, |
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DOI 10.1007/ 978-3-642-23294-7_5, © Springer-Verlag Berlin Heidelberg 2012 |
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5 Conventional Vitrectomy with 3-Port Trocar Setup |
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Pits & Pearls
Remember that about 10–20% of patients undergoing silicone oil removal will need additional surgery at a later stage, e.g. for retinal redetachment or recurrent vitreous haemorrhage. The silicone oil removal procedure is an ideal opportunity to deal with any lesser or larger problems during the surgery. Therefore, perform a careful examination preoperatively for appropriate planning of the surgical steps. Try to identify epiretinal membranes, which are a lot more difficult to see when silicone oil is still in situ. Be always prepared that additional vitreoretinal manipulations or even a ‘silicone oil exchange’ may be necessary.
Pits & Pearls
In particular, in units in which various silicone oils are used, always verify which type of silicone oil has to be removed. The setup to remove 1,000-cSt, 5,000-cSt or heavy silicone oil is different but they all look the same when performing fundoscopy. You can run into serious trouble if you think you are removing normal silicone oil but in fact it is heavy oil in situ and vice versa. Light silicone oils are easy to remove as they float on water. Heavy silicone oils are rather more difficult to remove because they are heavier than water.
Pits & Pearls No. 33
The surgical time to remove silicone oils depends on (1) the viscosity of the oil (1,000-cSt silicone oil < 1400 cSt Densiron 68® < 3,500-cSt Oxane Hd® < 5,000-cSt silicone oil) and (2) the size and length of the extraction cannula. The higher the viscosity, the bigger sized cannulas you should choose. A 23-gauge cannula is fine for 1,000-cSt silicone oil or for 1,400-cSt Densiron 68® but not for 5,000-cSt silicone oil. For 5,000-cSt silicone oil or for 3,400cSt Oxane Hd®, use a 19-gauge or even a 16-gauge cannula.
5.1 Silicone Oil, Densiron 68® and Oxane Hd® Removal |
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Fig. 5.1 Passive silicone oil removal: Both valves were removed. Now the silicone oil flows out passively. This surgical method takes longer than the active silicone oil removal. Remark: Heavy silicone oil cannot be removed with this method as it is heavier than water and therefore lies on the posterior pole
Instruments
1.3-port trocar (20-gauge or 23-gauge), 120D lens
2.Silicone oil 1,000 cSt: Active aspiration with 23-gauge plastic cannula (Medon or DORC) or 19-gauge metal cannula (Alcon)
Silicone oil 5000 cSt: 16-gauge cannula (Beaver-Visitec, UK, see material) with 10-ml syringe or 19-gauge metal cannula (Alcon) with silicone oil extraction set Oxane Hd® and Densiron 68®: 19-gauge metal cannula (Alcon)
3.Fluid needle
4.Scleral depressor
Possible tamponade
Air or gas
Individual steps
1.3-port system
2.Passive or active silicone oil removal
(Remark: Heavy silicone oils can only be removed actively)
3. Water/air exchange: aspiration of silicone oil bubbles from the water meniscus
4.Internal search
5.Removal of trocars
1.3-port system
2.Passive or active silicone oil removal
Passive removal of light silicone oil: This method is time consuming but avoids strong aspiration, which might lead to a suprachoroidal haemorrhage. Insert three 23-gauge trocars. Remove the valves of both instrument trocar cannulas, open the infusion and let the oil evacuate passively (Fig. 5.1). The eye must be positioned so that the silicone oil flows in the direction of the open trocar cannulas (Fig. 5.2).
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5 Conventional Vitrectomy with 3-Port Trocar Setup |
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Fig. 5.2 The passive silicone oil removal is almost done. You see the meniscus of the oil bubble in the pupil. By rotating the globe up with the help of the trocar forceps, you can remove the residual oil
Fig. 5.3 Active silicone oil removal: With a 23-gauge plastic cannula, which fits in a trocar cannula, you can aspirate the silicone oil. This plastic cannula is fixed to a syringe, which is attached to the pump in the vitrectomy machine. DORC. 1272.VFI06
Active removal of light silicone oil:
All methods are performed under BIOM view.
1.1,000-cSt silicone oil: Insert three 23-gauge trocars. Aspirate the silicone oil with a syringe attached to a 23-gauge cannula (active aspiration mode) (Figs. 5.3 and 2.29). When extracting the silicone oil, make sure that the tip of the aspiration cannula is always located in the silicone oil bubble and not in the water phase (Fig. 5.4).
2.1,000and 5,000-cSt silicone oils: Open the conjunctiva superotemporally, perform a perpendicular 19-gauge sclerotomy and aspirate actively with the 19-gauge metal cannula (Figs. 5.5 and 5.6).
3.5,000-cSt silicone oil: Perform an enlarged 20-gauge sclerotomy and aspirate manually with a 16-gauge cannula attached to a 10-ml syringe.
4.1,000and 5,000-cSt silicone oils: Silicone oil removal with the Constellation vitrectomy machine is simple and fast. Attach the adapter with syringe (silicone oil removal set, Alcon) to a valveless 23-gauge trocar and aspirate actively the silicone oil (Fig. 5.7). The removal time is approximately 1 min.
5.1 Silicone Oil, Densiron 68® and Oxane Hd® Removal |
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Fig. 5.4 Active silicone oil removal: On the right side, you see the yellow cannula.
The water phase is located in the back (retina), and the silicone oil phase is located in the front (lens)
Fig. 5.5 Active (heavy) silicone oil removal: A superotemporal sclerotomy was created for the 19G suction cannula (Alcon). The silicone oil syringe is connected to the vitrectomy machine. Afterwards, a fluid/ air exchange is performed
Fig. 5.6 One recognizes the meniscus of heavy silicone oil on the metal cannula. The posterior phase is heavy silicone oil, and the anterior phase is water