Outcomes of deep anterior lamellar keratoplasty using the small “big-bubble” technique

Session Details

Session Title: Cornea Surgical II

Session Date/Time: Tuesday 16/09/2014 | 08:00-10:30

Paper Time: 08:19

Venue: Boulevard B

First Author: : Y.Nahum ITALY

Co Author(s): :    C. Russo   B. Ricci-Filipovic   C. Bovone   M. Busin     

Abstract Details

Purpose:

To report the clinical outcomes of deep anterior lamellar keratoplasty (DALK) using a modified “big-bubble” technique.

Setting:

Retrospective, interventional case series of eyes operated at a private hospital by a single surgeon (MB).

Methods:

Review of the medical records of all consecutive patients who underwent a modified DALK (small “big-bubble“ technique) between April 2012 to December 2013 at Villa Igea Hospital, Forli'. The standardized procedure included: 1) Partial thickness 9mm trephination; 2) Pneumatic dissection of the stroma; 3) Removal of about half thickness of the anterior stroma within the 9.0 mm incision; 4) Marking of the central 6.0 mm optical zone, perforation of the bubble and removal of the deep stroma with exposure of Descemet within the 6.0 mm zone; 5) Suturing of a donor lamella, 350-400 micron in thickness and 9.0 mm in diameter, obtained by means of microkeratome-assisted dissection. When pneumatic dissection failed, Descemet was dissected by hand over the same 6 mm central optical zone. Complete suture removal was performed 12 months postoperatively. Main outcome measures were best spectacle-corrected visual acuity (BSCVA), and endothelial cell density (ECD). Differences between groups were tested with a two-tailed Student’s t-test (p values <0.05 were considered significant).

Results:

Seventy-two eyes of 72 patients were included in the study. Indications for surgery were keratoconus (n=66, 91.6%), herpetic scars (n=2, 2.7%) and corneal dystrophy, exposure scar, corneal neoplastic infiltration, as well as scar secondary to trichiasis (n=1, %1.4 each). Pneumatic dissection succeeded in 32 (44.4%), and failed in 40 eyes (55.5%) patients. Stromal dissection was completed by hand in 39 of 40 eyes: microperforation occurred in 4 eyes (only in one patient after successful formation of a big bubble) but the procedure could be completed uneventfully. Macroperforation occurred in 1 eye and required conversion into mushroom keratoplasty. The average follow-up time was 7.4 months (range=3 to 18 months). The overall mean BSCVA was 0.6±0.2 and the mean ECD was 2060±355cells/mm2. In those eyes with all sutures out (n=15), BSCVA improved significantly from 0.52±0.14 before, to 0.74±0.16 (p<0.005) after complete suture removal. No significant difference in BSCVA (p = 0.9) could be found between eyes with successful and eyes with failed pneumatic dissection (0.58±0.25 versus 0.58±0.21). Postoperative complications included partial graft melting (n=2) requiring graft exchange in one case, stromal rejection (n=1) and high-degree astigmatism requiring relaxing incisions (n=1).

Conclusions:

The results of small “big-bubble” DALK exposing only the central 6 mm of Descemet’s membrane compare favorably to those of conventional big bubble surgery. However, the modification offers the refractive advantages of a 9.0 mm graft, the safety of performing a descemetic dissection only over a limited area, and the elimination of irregularities in the surgical wound, as both the graft edge and the recipient edge need no hand refinement. Complications are rare and if pneumatic dissection fails, the procedure can be completed by hand in almost all cases without affecting final visual acuity.

Financial Interest:

One or more of the authors... travel has been funded, fully or partially, by a competing company