Intratunnel Phacofracture: A New MSICS Technique
In 2012, Sudhir Singh published a new manual small-incision cataract surgery (MSICS) technique based on his experience at Global Hospital Research Centre, Mount Abu,India .The MSICS and phacoemulsification are the most popular methods of cataract extraction today. The former is significantly faster, less expensive, and less technology-dependent than phacoemulsification and has been extensively practiced in developing countries such as India. However, the draw¬back of most commonly practiced MSICS techniques— Blumenthal, visco expression, irrigating wire vectis, and fish-hook needle—is that they all require a large incision of 7 to 9 mm, which leads to induced astigmatism. In the intratunnel phacofracture technique, in which the lens nucleus is broken inside a sub−6-mm sclerocorneal tunnel incision and removed. The nucleus removal steps take place inside the sclerocorneal tunnel, in contrast with other nucleotomy techniques in which this maneuvering takes place inside the anterior chamber.
Watch Video of Intratunnel Phacofracture on YouTube https://youtu.be/_nYIR3n_--o?list=PLO6iZMCr0FmxCYmg7Pxq_lf07K9Ki8CTA
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- 1 Anesthesia
- 2 Site of Incision
- 3 Surgical Steps
- 3.1 Cleaning and draping
- 3.2 Superior Rectus Bridle Suture
- 3.3 Conjunctival Flap
- 3.4 Sclera-corneal Tunnel
- 3.5 Central Circular Capsulorhexis
- 3.6 Hydrodissection Procedure
- 3.7 Nucleus Prolapse in the Anterior Chamber
- 3.8 Nucleus Management
- 3.9 Cortical Matter Clean Up
- 3.10 Intraocular Lens Implantation
- 3.11 Conjunctival Flap Reposition
- 3.12 Main Ports and Side ports Sealing
- 4 Reference
Manual small incision can be done performed under peribulbar or topical anesthesia.
Site of Incision
Site of incision is chosen according keratometry values (K1and K2).The superotemporal quadrant for right eye and the superonasal quadrant for left eye should be chosen if K1 and K2 difference is equal or less than 1.0 diopter (Figure 1). If K1 and K2 difference is more than 1.0 diopter then incision should be on steeper axis made. If K1 is steeper than K2 then superior incision (Figure 2) and If K2 is steeper than K1 then temporal incision (Figure 3).
Figure 1: If K1 and K2 difference is less than 1 diopter then superotemporal incision for right eye and superonasal for left eye.
Figure 2: If K1 is more than 1.0 diopter from K2 then superior incision for both the eyes.
Figure 3: If K2 is more than 1.0 diopter from K1 then temporal incision for both the eyes.
Cleaning and draping
The skin of the eyelids, lid margins and around the eye is cleaned with 10 percent solution of povidone-iodine solution. Drape is applied. Wire speculum is placed. Cul de sac is thoroughly washed with Ringer’s lactate solution or balanced salt solution.
Superior Rectus Bridle Suture
A 4/0 silk superior rectus bridle suture is placed beneath the tendon of the superior rectus muscle. It is helpful to positioning eye after local anesthesia. Superior rectus bridle suture is not used when surgery is planned under topical anesthesia.
A fornix based conjunctival flap at the limbus with a chord length of approximately 6.5 mm is made. After careful dissection of the Tenon’s capsule, light cautery is applied (Image 4).
Image 4: Fornix-based conjunctival flap, cautery and partial scleral groove demonstration
A 4- 6 mm scleral frown incision, 1.5 mm from the limbus is made with a 15 number Bard Parker blade (Image 5). A funnel shaped sclerocorneal tunnel incision is created with a steel crescent knife. One side port is made 90 degrees apart on either side of the scleral tunnel with a 15 degree knife temporally in right eye and nasally in left eye. With a 2.8 mm keratome, the anterior chamber is entered 1.5 mm into the clear cornea. Anterior chamber is entered with 1.5 mm in clear cornea with help of 3.2 mm keratome (Figure 6). The hydroxyl propyl methyl cellulose 2 % (HPMC) viscoelsatics is injected into anterior chamber.
Image 5: Sclerocorneal tunnel making demonstration
Image 6: Illustrates sclerocorneal tunnel dimensions in superior quadrant
Central Circular Capsulorhexis
The central circular capsulorhexis is made with help of 26 gauze needle capsulotome. If glow is poor then capsule was stained with trypan blue dye under the air bubble. Then viscoelsatics is injected and capsulorhexis is made. The size of capsulorhexis is depends on the size of the nucleus .It may vary from 5.5 mm to 7.5 mm (Figure 7). If nucleus size is anticipated large then two relaxing incisions are made at the margins of the capsulorhexis. Capsulorhexis can also be made by capsulorhexis forceps.
Image 7: Capsular staining and capsulorhexis creation with 26 G needle capsulotome
The Hydrodissection is made with 26 gauze cannula place on 2 CC syringe filled irrigating fluid.
Nucleus Prolapse in the Anterior Chamber
The internal incision of the tunnel is enlarged sideways to 7 mm the 5.1 mm keratome (Image 8) .Anterior chamber is formed again with viscoelsatics and the nucleus is rotated within the capsule using a Sinskey hook. The nucleus is prolapsed into anterior chamber using a Sinsky hook. A Sinskey hook is used to retract the capsulorhexis to engage the equator and lever out one pole of the nucleus outside the capsular bag and the rest of the nucleus is rotated into the anterior chamber. If the nucleus is too large then two or three relaxing incision are made at the capsulorhexis margins at equidistant (Image 9).
Image 8: Tunnel enlargement with 5 mm keratotome and enlargement of the internal incision with 2.8 mm keratotome
Image 9: Demonstration of the nucleus rotation and prolapse in anterior chamber
Up to this step all above mentioned steps are same as in other manual small incision techniques. Intratunnel phacofracture technique is different than other phacofracture techniques of anterior chamber. Enough viscoelsatics is placed between cornea and superior surface of the nucleus to protect endothelium; between nucleus and iris to keep away iris from nucleus. The nucleus is rotated within the capsule using a Sinskey hook. The globe is stabilized with tooth forceps and the small Lewis lens loop is introduced through the tunnel and positioned between the iris and the nucleus. The nucleus is engaged in the lens loop and slowly withdrawn from the anterior chamber while the posterior lip of the tunnel is depressed. Once the nucleus gets engaged in the tunnel, then the Lewis loop is pulled posteriorly and upwards. This causes breaking and removal of a part of the nucleus and other part remains engaged in the tunnel. By viscoelsatics the engaged part of the nucleus is pushed back into the anterior chamber and rotated so its longitudinal axis is coincided with longitudinal axis of the tunnel. Again viscoelsatics is placed between the cornea and superior surface of the nucleus and between the nucleus and iris. The lens loop is introduced through the tunnel and positioned between the iris and the remaining part of the nucleus. The remaining part of the nucleus is engaged in the lens loop and slowly withdrawn from the anterior chamber while the posterior lip of the tunnel is depressed. Most of the times remaining part of the nucleus comes out. If it still break down then remaining part again pushed in the anterior chamber with help of viscoelsatics and previous steps are repeated till it comes out (Image 10).
Image 10: Demonstration of intratunnel phacofracture using Levis lens loop
Watch Video of Intratunnel Phacofracture on YouTube
Cortical Matter Clean Up
The remaining cortical matter clean up is done with direct 23 gauge Simcoe irrigating aspirating cannula. The anterior chamber is formed with Viscoelsatics (Image 11).
Intraocular Lens Implantation
A single piece PMMA intraocular lens of 5.5-6.00 mm optic size and 12.5 mm total size is implanted into the capsular bag. The anterior chamber is washed out thoroughly by Simcoe irrigation aspiration canula using Ringer’s lactate solution (Image 11).
Image 11: Irrigation aspiration, intraocular lens implantation, wound sealing and conjunctival flap repositioning
Conjunctival Flap Reposition
The conjunctival flap is reposited back and cauterized at the edges.
Main Ports and Side ports Sealing
Main port and side ports are sealed with stromal hydration using a 26 gauze cannula. A 0.5 cc sub-conjuctival gentamycin with dexamethasone injection is given. Eye is pad patched
- Sudhir Singh. First Postoperative Day Visual Outcome Following 6 mm Manual Small Incision Cataract Surgery Using Intratunnel Phacofracture Technique. US Ophthalmic Review, 2014;7(1):26–30 .
- Sudhir Singh.Step By Step :intratunnel Phacofracture.Cataract & Refractive Surgery Today Europe.May 2016:38-41.