Transcript Analysis of Intraoperative Capsular Trauma Induced by a

Analysis of Intraoperative Capsular Trauma Induced by a
New Single-Use Polymer Irrigation/Aspiration Tip During
Posterior Capsule Polishing
Don Davis, MD, Peter Ness, MD, Surekha Maddula,
MD, Liliana Werner, MD, PhD, Nick Mamalis, MD
The authors have no financial interest in this product
This project was supported in part by a grant from Alcon and by an unrestricted grant from
Research to Prevent Blindness to the Department of Ophthalmology at the University of Utah
Background
Posterior capsule rupture is a serious complication of
cataract surgery. Roughly one-third of posterior capsule
ruptures occur during the irrigation/aspiration stage of
phacoemulsification1. Although posterior capsular
polishing does not influence rates of posterior capsule
opacification2, anterior capsular polishing can decrease
rates of anterior capsule opacification/fibrosis3 and capsular
contraction4. Because of this effect, some have advocated
the use of routine capsular polishing with implantation of
multifocal and other premium intraocular lenses that are
extremely susceptible to decentration from mild capsular
contraction5. The single-use polymer tip studied here was
manufactured to decrease posterior capsular trauma
during irrigation/aspiration and capsular polishing.
Purpose
To compare the safety and capsular friendliness of a
new single-use polymer irrigation/aspiration (I/A) port
with a standard metal I/A port in a Miyake cadaver eye
model.
A
A. Photomicrograph (20X) of metal I/A tip used in the
Pathology laboratory for research purposes. Note the
small metal discontinuity on the proximal irrigation port
opening that is common to reusable metal I/A tips.
B
B. Photomicrograph (20X) of single-use polymer I/A tip
without sleeve. Note the smooth irrigation port opening.
The tip is distensible with moderate pressure, and the
aspiration port edges are regular and smooth.
Material/Methods
One eye of each cadaver pair was treated with a standard metal I/A
tip (OD) while the contralateral eye was treated with a single–use
polymer I/A tip (OS).
Nine pairs of cadaver eyes were prepared using the Miyake/Apple
technique under open sky for better capsular visualization.
Following capsulorrhexis, and nucleus expression by
hydrodissection, cortex was removed by each respective I/A tip.
The aspiration port was then occluded on the posterior capsule and
swept in several 2-3 mm arcs in order to induce either capsular
rupture or zonular dehiscence.
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A
Miyake view of
posterior capsule
cleaned with
metal (A) or
silicone polymer
tip (B). Note the
striae in the
posterior capsule
as the aspiration
port is occluded
and swept in 23mm arcs.
B
Material/Methods II
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If the posterior capsule/ zonular apparatus remained
intact, the vacuum was increased in a stepwise fashion
to a maximum of 600 mmHg.
Flow rate and bottle height were fixed.
The eyes were assessed by subjectively documenting
zonular stretching/ dehiscence and objectively
measuring maximum vacuum
Miyake view of posterior capsule occluded
the aspiration port of the I/A tip.
withstood without capsular rupture. within
Note zonular compromise.
Due to the small sample
size and combination of two
variables into one graded
scale (with emphasis on
maximum vacuum), the
data was analyzed with the
Wilcoxon Ranked Sum test
for non-parametric data.
Results: Table of Study Data
Eye *
Number
Donor Age
(years)
Time from
Enucleation
to Study
Tip
Test Endpoint§
Comments
1
65
2 Days
Metal
Posterior capsule tear at 320 mmHg
-
2
65
2 Days
Polymer
4+ zonular stretching at 600 mmHg
-
69
3 Days
-
-
Tear in posterior capsule before test
4
69
3 Days
Polymer
3+ zonular stretching at 600 mmHg
-
5
50
3 Days
Metal
Posterior capsule tear at 250 mmHg
Significant zonular dialysis before test
6
50
3 Days
Polymer
3+ zonular stretching at 600 mmHg
Significant zonular dialysis before test
7
56
3 Days
Metal
Posterior capsule tear at 600 mmHg
-
8
56
3 Days
Polymer
Zonular and posterior capsule tear at 450mmHg
Complete zonular failure during test
9
69
2 Days
Metal
3+ zonular stretching at 600 mmHg
-
10
69
2 Days
Polymer
2+ zonular stretching at 600 mmHg
-
11
46
2 Days
Metal
Posterior capsule tear at 320 mmHg
-
12
46
2 Days
Polymer
Posterior capsule tear at 320 mmHg
-
13
78
2 Days
Metal
Zonular tear at 320 mmHg
-
14
78
2 Days
Polymer
2+ zonular stretching at 600 mmHg
-
15
86
3 Days
Metal
3+ zonular stretching at 600 mmHg
-
16
86
3 Days
Polymer
1+ zonular stretching at 600 mmHg
-
17
59
2 Days
Metal
Posterior capsule tear at 450 mmHg
-
18
59
2 Days
Polymer
1+ zonular stretching at 600 mmHg
-
19
86
2 Days
Metal
2+ zonular stretching at 600 mmHg
-
20
86
2 Days
Polymer
1+ zonular stretching at 600 mmHg
-
†
3
†
*Eye Numbers with the same color represent eye pairs
†Data was discarded because of tear in posterior capsule prior to study inception
§Zonular Stretching from 0-4+ was noted in the study. No zonular dehiscence was noted.
Results Summary
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Ten of 18 eyes were able to tolerate a maximum I/A
vacuum of 600 mmHg (3/9 metal tips and 7/9 polymer
tips) without structural compromise (zonular dehiscence
or posterior capsular rupture).
Miyake view of posterior capsule after capsular rupture was
Metal I/A tips induced 5
induced by a metal I/A tip.
capsular tears and one
zonular dehiscence
Polymer I/A tips induced
2 capsular tears.
There is a statistically
significance difference
between the metal and
polymer tips with respect
to structural compromise
(p= 0.015).
Conclusion

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Cortical removal and capsular polishing
with the new single-use polymer I/A port
is a safe alternative to using metal I/A tips
and may induce less trauma than metal
I/A tips.
Utilization of single-use I/A
tips is also suitable to
reduce the likelihood of
toxic anterior segment
syndrome (TASS)6.
Anterior segment photo of a patient
with TASS – Post-operative Day 1
from phacoemulsification with
intraocular lens placement.
References
1. Gimbel H, Sun R, Ferensowicz M, Penno EA, Kamal A. Intraoperative
Management of Posterior Capsule Tears in Phacoemulsification and
Intraocular Lens Implantation. Ophthalmology. 2001;108:2186–92.
2. Shah SK, Praveen MR, Kaul A, Vasavada AR, Shah GD, Nihalani BR.
Impact of anterior capsule polishing on anterior capsule opacification
after cataract surgery: a randomized clinical trial. J Cataract Refract
Surg. 2010 Feb;36(2):208-14.
3. Sacu S, Menapace R, Wirtitsch M, Buehl W, Rainer G, Findl O. Effect of
anterior capsule polishing on fibrotic capsule opacification: three-year
results. J Cataract Refract Surg. 2004 Nov; 30(11):2322-7.
4. Tadros A, Bhatt UK, Karim A, Zaheer A, and Thomas PW, Removal of lens
epithelial cells and the effect on capsulorhexis size. J Cataract Refract
Surg. 2005 Aug; 31(8):1569–74.
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Synchrony dual-optic accommodating intraocular lens. Part 2: pilot
clinical evaluation. J Cataract Refract Surg. 2007 Jan;33(1):47-52.
6. Mamalis N, Edelhauser HF, Dawson DG, Chew J, LeBoyer RM, Werner L.
Toxic Anterior Segment Syndrome. J Cataract Refract Surg. 2006
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