Incomplete Flaps

ETIOLOGY AND INCIDENCE OF INCOMPLETE FLAPS

Femtosecond LASIK

An incomplete flap may happen with femtosecond LASIK if suction proves to be unsuccessful, despite repeated attempts after an initial aborted pass. It may also occur if the tear meniscus, debris, ink marks, or epithelial defect shields an area of the flap from the laser ablation. The incidence of incomplete flaps with femtosecond LASIK is approximately 0.03%.^1,2

Microkeratome LASIK

Incomplete flaps may occur with microkeratome LASIK after loss of suction. Microkeratome jamming due to either electrical failure or mechanical obstacles may also result in incomplete flaps. Lashes, drape, loose epithelium, and precipitated salt from the irrigating solution have been recognized as possible impediments to smooth keratome head progression. Incomplete flaps also occur when the gear advancement mechanism jams or is inadequate. The incidence of incomplete flaps with microkeratome LASIK varies between 0.23% and 1.2%.³

Figure 8-1. Initial surgery resulted in a suction loss during the raster cut. The raster and side cuts were not repeated in this case.

FEMTOSECOND LASIK COMPLICATIONS AND IMMEDIATE SOLUTIONS

Complication #1: Incomplete Flap (Unable to Lift)

Video section: 0 minutes 6 seconds

Platform: IntraLase FS60 kilohertz (kHz) (Abbott Medical Optics)

Flap diameter: 9.3 mm

Flap target depth: 100 microns (µm)

The initial surgery resulted in a partial suction loss. Laser treatment was continued. Adherence was found during dissection at the place where suction was lost (video 8; time: 0 minutes 6 seconds; Figures 8-1 and 8-2).

Some practical measures are as follows:

Discontinue the laser treatment immediately and repeat the raster cut.
Start the mechanical flap dissection in front of and behind the suspected uncut zone (place where suction was lost during the first raster cut).
Blunt dissection and the use of flap forceps may release adherence.
Extensive adherence may result in a flap tear with blunt dissection.

Figure 8-2. Flap lifting revealed adherence at the same place where suction was lost. Surgery was aborted, and the patient underwent a surface refractive procedure 9 days later.

Abort the procedure.
Plan for a future surface refractive procedure.

Complication #2: Incomplete Flap (Unable to Lift)

Video section: 1 minute 53 seconds

Platform: WaveLight FS200 (Alcon Labs)

Flap diameter: 9.3 mm

Flap target depth: 100 µm

The initial surgery resulted in an irregular flap cut pattern. Laser treatment was continued. The flap was unable to be lifted (video 2; time: 1 minute 53 seconds; Figures 8-3 and 8-4).

Some practical measures are as follows:

An irregular raster cut pattern may be due to a deeper stromal cut.
Abort the procedure.
Plan for a future surface refractive procedure.

Figure 8-3. Initial surgery resulted in an irregular raster and site cut configuration.

Figure 8-4. Flap lifting was not possible. Surgery was aborted, and the patient underwent a surface refractive procedure 14 days later.

Complication #3: Incomplete Flap (Debris at Interface; Unable to Lift)

Video section: 5 minutes 18 seconds

Platform: IntraLase FS60 kHz

Flap diameter: 9.3 mm

Flap target depth: 100 µm

The initial surgery resulted in an incomplete flap due to debris at the patient interface. Adherence was found during dissection at the place where the debris was found (video 8; time: 5 minutes 18 seconds; Figures 8-5, 8-6, and 8-7).

Figure 8-5. Initial surgery showed debris at patient interface (red arrow).

Figure 8-6. Uncut area at flap-stroma interface (red arrow).

Figure 8-7. Flap lifting was not possible (red arrow). Surgery was aborted, and the patient underwent a surface refractive procedure 7 days later.

Some practical measures are as follows:

Start the mechanical flap dissection in front of and behind the suspected uncut zone.
Blunt dissection and the use of flap forceps may release adherence.
Extensive adherence may result in a flap tear with blunt dissection.
Abort the procedure.
Plan for a future surface refractive procedure.

Complication #4: Incomplete Flap (Iatrogenic Epithelial Defect; Unable to Lift)

Video section: 7 minutes 10 seconds

Platform: WaveLight FS200

Flap diameter: 9.3 mm

Flap target depth: 100 µm

The initial surgery resulted in an incomplete flap due to an iatrogenic epithelial defect. Adherence was found during dissection at the place of the epithelial defect (video 8; time: 7 minutes 10 seconds; and Figures 8-8, 8-9, and 8-10).

Some practical measures are as follows:

Start the mechanical flap dissection in front of and behind the suspected uncut zone.
Blunt dissection and the use of flap forceps may release adherence.
Extensive adherence may result in a flap tear with blunt dissection.
Abort the procedure.
Plan for a future surface refractive procedure.