This study compared outcomes of supra-Tenon placement of 250 mm2 Baerveldt implants versus infra-Tenon placement of 350 mm2 implants. The researchers found that supra-Tenon placement of the smaller implant was as effective at controlling intraocular pressure as infra-Tenon placement of the larger implant, with fewer needed glaucoma medications. Complication rates were similar between groups. Supra-Tenon placement may offer efficacy comparable to traditional infra-Tenon surgery while negating any potential size benefit of larger implants.

1. Supra-Tenon Capsule Placement of Baerveldt Implant
Department of Ophthalmology, California Pacific Medical Center, San Francisco, CA
Aileen Sy, MD and H. George Tanaka, MD
Methods
• Retrospective chart review was performed on all patients
receiving Baerveldt implants from March 2012 to March
2014. All supra-Tenon GDD were 250 mm2 implants and all
infra-Tenon GDD were 350 mm2.
• Information gathered included age, gender, race, type of
glaucoma, pre-surgical visual acuity (VA), intraocular
pressure (IOP) and number of glaucoma drops, post-
surgical visual acuity, intraocular pressure and number of
glaucoma drops, follow-up time and complications.
• Baseline demographics were analyzed by implant location
with Fisher’s exact test for categorical variables and
Wilcoxon rank-sum test for continuous variables. T-test and
multilinear regression models were used to analyze
outcome measures.
Purpose
• To compare the efficacy of supra-Tenon placement of 250
mm2 versus infra-Tenon placement of 350 mm2 Baerveldt
glaucoma drainage device (GDD).
Background
• Placement of GDDs has traditionally been beneath the
Tenon capsule.
• Tenon capsule has been found to be pro-inflammatory and
is thought to contribute to GDD bleb fibrosis and failure.1,2
• Supra-Tenon placement of GDD has been proposed as a
means of eliminating fibrosis from Tenon tissue.1,2,3,4
• Supra-Tenon capsule placement of the Molteno (130 mm2)
and Molteno 3 (175 mm2) glaucoma implant has been
reported in patients failing prior filtration or implant surgery.
Results showed effective intraocular pressure control and
bleb formation, supporting supra-Tenon placement as a
viable surgical option.3,4 Additionally, supra-Tenon
placement appeared to offset any benefit from larger plate
size.
• No prior studies have investigated supra-Tenon placement
of the more commonly used Baerveldt implant in eyes
without prior GDD implant.
Conclusions
and Future Investigations
References
1. Freedman J. Molteno Developments in Traditional Outflow Implants. In: Samples
JR, Ahmed IIK, eds. Surgical Innovations in Glaucoma. New York: Springer
Science+Business Media; 2014:209-220.
2. Freedman J, Iserovich P. Pro-inflammatory cytokines in glaucomatous aqueous and
encysted Molteno implant blebs and their relationship to pressure. Investigative
Ophthalmology & Visual Science. Jul 2013;54(7):4851-4855.
3. Freedman J, Bhandari R. Supra-tenon capsule placement of original Molteno vs
Molteno 3 tube implants in black patients with refractory glaucoma: a single-
surgeon experience. Archives of Ophthalmology. Aug 2011;129(8):993-997.
4. Freedman J, Chamnongvongse P. Supra-Tenon's capsule placement of a single-
plate Molteno implant. The British Journal of Ophthalmology. May 2008;92(5):669-
672.
Table 1. Baseline Characteristics
Acknowledgments
Thanks to Pacific Vision Foundation for their support of this
research.
Results
• No significant difference in age, gender ratio, pre-operative
IOP, pre-operative number of IOP lowering medications, prior
surgeries or pre-operative VA was found.
• A shorter follow up in supra-Tenon implant group was noted,
but not found to be statistically significant (p=0.40).
• No difference in post-operative IOP was found (p=0.86).
• Fewer IOP lowering medications were required in the supra-
Tenon implant group at last follow-up (p=0.09), significant by
p<0.1 criteria but not by p<0.05 criteria.
• No difference in post-operative VA was found (p=0.25).
• Time to pulling tube-occluding stent was shorter in the infra-
Tenon group, but not statistically significant (p=0.14).
• The most common post-operative complication was hypotony
and choroidals (4/26 supra-Tenon, 5/32, infra-Tenon). Other
complications in the supra-Tenon group included an encysted
bleb restricting extraocular movements and focal tube
exposure, one case of each. Infra-Tenon complications
included binocular diplopia, flat AC, hyphema, high IOP and
exposed plate, one case of each.
• Surgical revisions were required in three (11.2%) supra-
Tenon cases and three (9.4%) infra-Tenon cases.
Figure 1. Supra-Tenon Surgical Technique
Table 2. Post-surgical Outcomes
• Supra-Tenon placement of the smaller 250 mm2 Baerveldt
implant can effectively control IOP as compared to the larger
250 mm2 infra-Tenon implant placement. It appears supra-
Tenon placement negates smaller implant size.
• Rate of complications did not appear to be higher with
supra-Tenon placement.
• Supra-Tenon placement of Baerveldt implant may allow for
fewer IOP lowering medications than traditional infra-Tenon
placement.
• Success of supra-Tenon placement of Baerveldt implant in
patients with prior infra-Tenon Ahmed implant is currently
being evaluated.
Supra-Tenon
(N=26)
Mean (median)
Infra-Tenons
(N=32)
Mean (median)
P-value
Age 70 (72) 69.3 (72) 0.94
Gender (M:F) 1:1 1:1 1.00
Prior surgeries
(No.)
1.2 (1) 1.3 (1) 0.70
Length of follow-
up (months)
9.6 (9) 12.7 (10.5) 0.40
Pre-operative
IOP
24.2 (22) 26.0 (23) 0.70
Pre-operative
medications (No.)
3.6 (4) 3.4 (4) 0.39
Pre-operative
visual acuity (VA,
logMAR)
0.71 (0.3) 0.70 (0.3) 0.98
Supra-Tenon
(N=26)
Mean (median)
Infra-Tenons
(N=32)
Mean (median)
P-value
Post-operative
IOP
12.6 (13) 12.3 (12) 0.86
Post-operative
medications (No.)
1.08 (0) 1.84 (2) 0.09
Post-operative VA
(logMAR)
0.67 (0.3) 0.95 (0.4) 0.25
Time to pulling
tube-occluding
stent (days)
47.6 (32) 33.4 (28) 0.14
Surgical revision 3 (11.2%) 3 (9.4%)
Second glaucoma
procedure
0 1 (3.1%)