LPK technique gives boost to advanced keratoconus

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Lamellar-perforating keratoplasty is a new excimer laser-assisted transplantation technique developed for eyes with advanced keratoconus.

By Cheryl Guttman Krader; Reviewed by Cesar Carriazo, MD

Bogota, Colombia-Outcomes of eyes undergoing lamellar-perforating keratoplasty (LPK) show this new partial-thickness corneal transplantation technique is a suitable alternative to penetrating keratoplasty for eyes with advanced keratoconus, said Cesar Carriazo, MD.

“Patients with advanced keratoconus have had no options for visual rehabilitation other than penetrating keratoplasty,” said Dr. Carriazo, founder and scientific director, Carriazo Centro Oftalmologico, Barranquilla Colombia and refractive and anterior segment ophthalmologist, Instituto Barraquer de America, Bogota, Colombi.. “With LPK we can offer them the advantages of a minimally invasive procedure.”

Dr. Carriazo developed LPK as a modification to pachymetry-assisted lamellar keratoplasty (PALK).

How it’s done

In LPK, as in PALK, an excimer laser (Amaris 1050RS, Schwind) is used to perform a pachymetry-guided 8-mm ablation of the recipient eye, leaving 100 μm of posterior stroma, explained Dr. Carriazo, founder and scientific director, Carriazo Centro Oftalmologico, Barranquilla Colombia and refractive and anterior segment ophthalmologist, Instituto Barraquer de America, Bogota, Colombia.

Then, in LPK, the laser is used to create multiple microperforations around the periphery of the stromal bed. Due to the fast speed of the laser (1,050 Hz), the laser treatment of the recipient eye takes just about 90 seconds.

After placing air in the anterior chamber, an 8-mm graft, created by removing the endothelium from the donor cornea, is placed onto the dried recipient bed and fixated with 16 nylon 10-0 interrupted sutures.

The rationale for perforating the periphery of the host stromal bed in LPK is to enable better coaptation of the donor and host edges, he noted. The microperforations cause the recipient bed to sink inward toward the anterior chamber and thereby the technique allows the donor tissue to lie deeper in the recipient base.

“Since the recipient eye has 100 μm of residual stroma, the upper surface of the graft lies slightly above the level of the host cornea after pachymetry-assisted lamellar keratoplasty,” Dr. Carriazo said. “In eyes with advanced keratoconus where the cornea is thinner in the periphery as well as centrally, so the difference in height between the graft and host is even greater. That discrepancy can lead to high astigmatism.”

The microperforation technique addresses this problem, he said.

LPK outcomes

To demonstrate the outcomes of LPK, Dr. Carriazo reviewed data from a series of 11 eyes. Mean (range) pachymetry was 452.6 (379 to 600) μm preoperatively and 670 (500 to 712) μm at 6 months.  Mean cylinder was about –4 D preoperatively and was improved after removal of the stitches to –2 D at 2 years after surgery. Mean SE improved from about –5 D preoperatively to about –1 D at 2 years after the surgery.

All eyes achieved improved uncorrected visual acuity and best-corrected visual acuity (BCVA), although haze developing after subsequent refractive surgery limited BCVA gain in 3 eyes. Endothelial cell loss averaged just 11%, Dr. Carriazo noted.

Cesar Carriazo, MD

E: ccarriazo@carriazo.com

Dr. Carriazo receives royalty fees from Schwind.

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