This article is more than 5 years old. Information may no longer be current.
Sutureless femtosecond-assisted anterior lamellar keratoplasty may treat corneal pathologies
Selective corneal transplantation includes a variety of modern day surgical techniques to cater to two large categories: those with a healthy corneal endothelium and others with corneal endothelial decompensation. In the former group with a healthy corneal endothelium, an anterior lamellar keratoplasty may be chosen as the surgical technique, while in the latter group, a posterior lamellar keratoplasty technique such as endothelial keratoplasty may be used, which includes both Descemet’s stripping endothelial keratoplasty and Descemet’s membrane endothelial keratoplasty.
ALK retains the posterior portions of the patient’s healthy cornea, including the corneal endothelium, thus affording the advantage of no corneal endothelial graft rejection following such surgical procedures. ALK may be divided into different procedures according to the John-Malbran classification: superficial ALK (160 µm), mid ALK (160 µm to 400 µm), deep ALK (470 µm to 495 µm) and total ALK (500 µm to 520 µm). The final quality of vision in ALK procedures is largely dependent on the type of donor-recipient corneal interface and the depth of this interface within the final surgically reconstructed cornea. In general, the deeper the corneal interface, the better the visual quality following the procedure.
Ocular surface re-epithelialization and restoration may be augmented by the use of amniotic membrane, which includes cryopreserved amniotic membrane, such as from Bio-Tissue, and dehydrated amniotic membrane, such as AmbioDisk (IOP Ophthalmics) and BioDOptix (BioD). Cryopreservation appears to better preserve the structural and biological signaling molecules of fetal tissues, such as high molecular weight hyaluronan and proteins, HC-HA and PTX3.
In this column, Bhuvanagiri and Ambati describe their technique of sutureless femtosecond-assisted anterior lamellar keratoplasty. Larger studies comparing this technique to other ALK techniques would provide data on the overall efficacy, safety and visual outcomes.
Thomas “TJ” John, MD
OSN Surgical Maneuvers Editor
Figure 1. Patient’s right cornea with a deep central scar after docking and before undergoing the femtosecond laser cut.
Figure 2. Performing the femtosecond laser cut on the recipient corneal stroma using a fifth-generation IntraLase femtosecond laser.
Images: Bhuvanagiri S, Ambati B
Figure 3. Clean corneal stromal bed after removal of the patient’s anterior lamella before placement of the donor cornea.
Anterior lamellar keratoplasty is a surgical procedure that is used to treat many corneal pathologies such as keratoconus, corneal ectasia, corneal scars and other pathologies that does not involve the corneal endothelium. In femtosecond-assisted ALK (FALK), the surgeon dissects the cornea into two layers and removes the front scarred part using a femtosecond laser instead of cutting the cornea manually by hand. A matching area of healthy tissue from a donor cornea is then used to replace the defective part of the recipient cornea. While the use of laser increases the stability of the graft and helps with wound healing, the use of sutures prolongs wound healing and increases the risk of iatrogenic astigmatism and corneal graft rejection. Therefore, ophthalmic surgeons are opting for sutureless techniques such as the use of ocular sealants to reduce postoperative inflammation and wound healing time. Ocular sealants have been successfully used in ophthalmic surgeries such as pterygium removal and cataract surgery, which resulted in improved postoperative patient comfort and lower rates of inflammation compared with suturing.
In order to treat a patient’s deep corneal scar, a novel sutureless corneal transplant method was performed during FALK using ReSure hydrogel tissue adhesive (Ocular Therapeutix) and lyophilized amniotic membrane (AmbioDisk, IOP Ophthalmics) to reduce the need for and risks of sutures, facilitate re-epithelialization and reduce operative time.
Figure 4. Placement of donor lamella onto the clean corneal stromal bed of the patient (left). Securing the donor’s lamella using ReSure hydrogel tissue adhesive to seal the edges of the donor corneal rim (right).
Figure 5. Placement of AmbioDisk over the donor corneal transplant (left). Securing the AmbioDisk using ReSure glue by sealing around the edges of the amniotic membrane (right).
Surgical technique
The sutureless FALK treatment was planned for a 35-year-old woman with a deep central corneal scar in the right eye, as seen in Figure 1. The fifth-generation IntraLase femtosecond laser (Abbott Medical Optics) was used to perform the first part of the procedure. Under topical anesthesia (proparacaine hydrochloride ophthalmic solution USP, 0.5%), a disposable suction ring was placed at the scleral-limbal margin to stabilize the eye (Figure 1). After docking, the femtosecond laser cut, using 1.15 µJ of energy, was performed on the recipient corneal stroma to create an anterior lamellar cut of 260 µm thickness at 8.5 mm diameter with an 8.4 mm anterior side cut (Figure 2).
After the stromal laser cut, the patient was transported to the operating room. The dissected anterior lamella was removed with an iridodialysis spatula and Polack forceps, leaving a clean stromal bed (Figure 3). Then the precut donor cornea with an anterior lamellar thickness of 195 µm was brought onto the field and cut using an 8.5 mm corneal punch. The donor lamella was placed in the patient’s right eye and centered onto the stromal bed (Figure 4). A flap roller was used to iron and smooth the donor lamella. The donor lamella was then sealed around the edges with ReSure to secure the donor rim (Figure 4). AmbioDisk was placed over the cornea and secured with ReSure (Figure 5).
Figure 6. The patient’s cornea after the placement of the 18-mm bandage contact lens over the amniotic membrane transplant.
An 18-mm bandage contact lens (Kontur) was placed over the amniotic membrane transplant (Figure 6). The speculum was removed. Prednisone and gatifloxacin drops were instilled into the eye. A patch and shield were placed. No intraoperative or immediate postoperative complications occurred. The patient was comfortable and stable and was transferred to the recovery room.
Even though the use of FALK increases the precision of lamellar cuts, enhances graft stability and reduces wound healing time, the use of sutures still compromises the beneficial effects of laser. Because ReSure and AmbioDisk are used in less invasive sutureless ophthalmic surgeries such as pterygium removal with successful results, we decided to use it in performing sutureless FALK. Larger clinical studies should be done in order to study and confirm the benefits of using ReSure and AmbioDisk in FALK.
- References:
- Cooke M, et al. J Wound Care. 2014;doi:10.12968/jowc.2014.23.10.465.
- Christo CG, et al. Cornea. 2001;doi:10.1097/00003226-200111000-00008.
- John T. Expert Rev Ophthalmol. 2006;1(1):5-7.
- John T, ed. Chapter 4. Surgical Techniques in Anterior and Posterior Lamellar Keratoplasty. New Delhi, India: Jaypee Brothers Medical Publishers; 2006:36-43.
- Pan HW, et al. Ophthalmology. 2011;doi:10.1016/j.ophtha.2010.10.033.
- Panda A, et al. Indian J Ophthalmol. 2009;doi:10.4103/0301-4738.55079.
- Sarnicola E, et al. Cornea. 2015;doi:10.1159/000381495.
- For more information:
- Bala Ambati, MD, PhD, MBA, can be reached at 65 Mario Capecchi Dr., Salt Lake City, UT 84132; email: bambati@gmail.com.
- Sai Bhuvanagiri, BS, can be reached at 274 E. 800 S., Apt #1, Salt Lake City, UT 84102; email: sai.bhuvanagiri@gmail.com.
- Edited by Thomas “TJ” John, MD, a clinical associate professor at Loyola University at Chicago and in private practice in Oak Brook, Tinley Park and Oak Lawn, Ill. He can be reached at email: tjcornea@gmail.com.
Disclosures: Ambati and Bhuvanagiri report no relevant financial disclosures. John reports he is a consultant for and has a small equity interest in Bio-Tissue.