International Journal of Impotence Research (2003) 15, Suppl 5, S132–S133
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Cylinder sizing: less is more
DK Montague1* and KW Angermeier1
1
Section of Prosthetic Surgery and Genitourethral Reconstruction, Glickman Urological Institute, Cleveland Clinic
Foundation, Cleveland, Ohio, USA
In penile prosthesis implantation traditional cylinder-sizing techniques frequently result in penile
cylinders that are too long for the corpora cavernosa. This can result in premature cylinder wear
leading to cylinder aneurysm or fluid loss. Additionally, in the case of the length expanding Ultrex
penile prosthesis, cylinders that are too long can result in an S-shaped cylinder deformity. We
describe a cylinder measurement technique that avoids the problem of oversizing.
International Journal of Impotence Research (2003) 15, Suppl 5, S132–S133. doi:10.1038/
sj.ijir.3901088
Keywords: penile prosthesis; penile implantation
Traditional sizing technique
Many implanters use the traditional cylinder sizing
technique that places a reference suture at the midpoint of the corporotomy. Distal and proximal
measurements are then made from this reference
suture and added to determine cylinder length. A
rigid sizing instrument is used for these measurements and the measurement is taken at the surface of
the corpus cavernosum. The true length of the
corpus cavernosum is the length of a line that
extends from the proximal to the distal end of the
corpus cavernosum passing through the center of
the corporeal body. The traditional sizing technique
over estimates this true length by approximately
2 cm (Figure 1).
This cylinder sizing error became apparent when
reports of the S-shaped cylinder deformity (Figure 2)
appeared after introduction of the girth and length
expanding Ultrex cylinder.1 With these new lengthexpanding cylinders, which have memory, an initial
small deformity in the oversized cylinder expanded
with time and became clinically apparent creating
the so-called S-shaped deformity. With our measurement technique, which avoids the error, we have
avoided this particular complication.2,3
Most inflatable penile prostheses have cylinders
that expand only in girth and not in length. Any
*Correspondence: DK Montague, MD, Section of Prosthetic Surgery and Genitourethral Reconstruction, Glickman
Urological Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA.
E-mail: [email protected]
oversizing error thus remains constant and usually
not clinically apparent. However, a cylinder that is
too long has a fold at the base of the penis. This is
the area of the cylinder that usually fails (Figure 3),
and while there is no proof, it seems reasonable to
suspect that this fold subjects this portion of the
cylinder to premature failure.
American Medical System’s Ambicor Penile Prosthesis is a two-piece inflatable device that has
cylinders that when deflated are collapsed and
when inflated become round and rigid without any
girth or length expansion. When these cylinders are
too long, a flexing of the penis with lateral folds at
the flex point occurs producing a characteristic
deformity (Figure 4).
Suggested sizing technique
As the magnitude of the sizing error is about 2 cm,
we suggest making a 2 cm corporotomy and then
using the respective ends of the corporotomy for the
distal and proximal measurements that are then
summed to determine cylinder length. Thus, the
2 cm corporotomy is not included in the measurement (Figure 5). This usually results in a cylinder
that fills the corpus cavernosum completely without
bulging. After the cylinder is implanted but before
the corporotomy is closed, the cylinder is inspected
through the open corporotomy. It should lie flatly.
The cylinder must be full of fluid but not inflated in
order to properly make this determination. Proximal
palpation (if the penoscrotal approach is being used)
insures that the proximal cylinder goes all the way
Cylinder sizing: less or more
DK Montague and KW Angermeier
S133
Figure 1 Traditional sizing technique.
Figure 4 Ambicor deformity from device that is too long for the
corpus cavernosum.
Figure 5 Suggested sizing technique. The 2 cm corporotomy is
not included in the measurement.
Figure 2 S-shaped cylinder deformity (courtesy of Dr Stephen K
Wilson).
down to the attachment of the crus to the bone. The
penis is then released from the ring retractor and
palpation insures that the distal cylinder reaches the
distal corpus cavernosum and provides adequate
support for the glans. If necessary, the cylinder can
be removed and rear tip extenders can be added or
removed to achieve proper fit. However, with this
measurement technique the correct fit is obtained
initially in the vast majority of cases. After proper fit
has been obtained, the corporotomy is closed.
References
Figure 3 Cylinder failure in portion of cylinder that is at the base
of the penis.
1 Wilson SK, Cleves MA, Delk II JR. Ultrex cylinders: problems
with uncontrolled lengthening (the S-shaped deformity).
J Urol 1996; 155: 135.
2 Montague DK, Lakin MM. Early experience with the controlled girth and length expanding cylinder of the American
Medical Systems Ultrex penile prosthesis. J Urol 1992; 148: 1444.
3 Milbank AJ et al. Mechanical failure with the AMS Ultrex
inflatable penile prosthesis: pre- and post-1993 structural
modification. J Urol 2002; 167: 2502.
International Journal of Impotence Research