Modified Instrumentation to Simplify “Big Bubble technique” for Deep Anterior Lamellar Keratoplasty (DALK) Dr Rajesh Fogla DNB, FRCS, MMed Senior Consultant, Corneal Surgeon Apollo Hospitals, Hyderabad, INDIA dr_fogla@yahoo.com www.corneaclinic.com Financial Interest : No Financial Interest The Fogla DALK instruments were developed by Storz (B&L) free of cost

Big Bubble Technique DALK First described by Dr Mohammed Anwar Technique uses forceful injection of air at 80% corneal depth using 27G needle connected to an air filled syringe Air pressure results in separation of the Descemet Membrane (DM) from stroma. Edge of DM separation is outlined with a dense white band This allows replacement of pathological stroma with donor tissue devoid of DM.

Big Bubble Technique DALK Original technique - Steep learning curve Technique requires placement of sharp 27G needle at > 80% depth of cornea. Superficial placement of needle tip results in stromal emphysema and lateral movement of air towards the limbus Deeper placement of needle tip increases risk of perforation into the anterior chamber Success rate of achieving Big Bubble is 65-80% even in hands of experienced surgeons

Modified Instruments for Big Bubble DALK Surgery

Deflating the Big Bubble using sharp 15 blade with cutting edge facing upwards Using the Fogla Trifacet spatula the space in between the stroma and DM is entered, and the overlying stroma incised using No 15 blade to enlarge the opening

Using Fogla R & L Scissors, the overlying stroma is split into 4 quadrants Using Fogla R & L Scissors, each quadrant of stromal tissue is excised carefully at the edge of corneal trephination

Note bare DM after excision of stromal tissue, Donor tissue is prepared by peeling off DM using fine tying forceps, Donor tissue is placed on the host bed and sutured using 10-0 Nylon suture Post operative outcome is excellent following Big Bubble technique of DALK surgery This technique also allows better utilization of donor tissues from the Eyebank

Modified Technique & Instrumentation Instruments designed in 2006 Over 200 consecutive DALK procedures performed since then Big Bubble achieved in > 95% cases Microperforation occurred in 1.5% cases (3) None of the cases converted to penetrating keratoplasty Average uncorrected visual acuity 20/60, best spectacle corrected visual acuity of 20/25.

Conclusion Modified Big Bubble technique of DALK surgery is easier to master with lower complication rates using the Fogla set of DALK instruments. Surgeons will now be able to apply this surgical technique to a wide variety of corneal disorders with healthy endothelium requiring corneal transplantation surgery

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