Page 41 - Journal of Special Operations Medicine - Winter 2014

Purpose corrected axial images resulted in true inlet and outlet
images. For true inlet and true outlet images, the AP
Our purpose was to evaluate the compressive function distance between the sacrum and the posterior margin
of the JETT in the reduction of pelvic ring injuries in a of the symphysis pubis was made (AP inlet and AP out-
cadaveric model. We hypothesized that the JETT device let) (Figure 1). Transverse measurements were made us-
would both perform and maintain the adequate reduc- ing the bony landmarks of the ischial spines (transverse
tion of the pelvic ring disruptions and injuries.
inlet) and the medial walls of the quadrilateral plates
(transverse outlet) (Figure 2). The measurements were
made at the maximal diameters of the inlet and outlet
Methods
visualized on the images. The predisruption image mea-
surements were references for comparison to post-JETT
Study Design measurements.
Our pelvic disruption and injury model used fresh hu-
man cadavers to create an APC III injury. Predisruption Figure 1 (A) Sagittal cross section on CT scan of AP inlet
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radiographic measurements of the intact pelvis were es- measurement is made on the red line. (B) Sagittal cross
tablished. APC III injury was then created through an section on CT scan of AP outlet measurement is made on
anterior intrapelvic approach. Postinjury radiography the red line.
measurements were obtained through the same tech-
nique. The JETT device was then applied, and post- (A) (B)
reduction measurements were obtained via the same
technique. Preinjury, postinjury, and postreduction mea-
surements were compared to evaluate the effectiveness
of the JETT in reduction of an APC III injury. Approval
was obtained from our institutional review board for
cadaver use for this study.

Cadaver Information
Two fresh human cadavers were acquired through the
University of Texas Medical School Houston Willed Figure 2 (A) Transverse inlet measurement is made on the
red line between the two ischial spines. (B) Transverse outlet
Body Program. The cadavers were not embalmed and measurement is made on the red line between the two
were not frozen but instead were refrigerated after death quadrilateral plates.
and maintained at a constant temperature above freez-
ing at 45ºF before use. All cadavers were placed at am- (A) (B)
bient temperature 24 hours before use to allow them to
come to room temperature.

Predisruption Radiography
CT scans of the intact pelvic ring were taken before dis-
section. The scanner was a 64-slice Siemens Somatom 64
(Siemens AG, Erlangen, Germany; http://www.siemens
.com/entry/cc/en/). This predisruption and injury CT
scan provided baseline reference data for pelvic volume
and architecture so that the extent of injury and return Pelvic Disruption Technique and Device Application
to baseline achieved by each device can be measured APC III injuries of the Young and Burgess classification
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against the preinjury, intact pelvis. were then created in two cadavers using a Pfannenstiel
and anterior intrapelvic approach to the anterior ring
Measurements were made on the corrected axial images and sacroiliac joints. Osteotomes were used to create
that were generated using a three-dimensional work sta- anterior injuries in both cadavers with disruption of
tion (TeraRecon, www.terarecon.com). A tight volumet- the pubic symphysis using the osteotome to penetrate
ric CT acquisition was performed of the pelvis. These the cartilage. Bilateral superior and inferior pubic rami
images were converted into transaxial images in plane fractures were also created with the osteotome. Finally,
with axis of the pelvis (tilted axial images). Transaxial bilateral posterior pelvic ring injuries were created
images of the pelvis were generated from the spiral da- with osteotomes through the anterior sacroiliac joint
taset at three stages; pre injury and disruption, post in- and ilium (Figure 3). Sacrospinous and sacrotuberous
jury and disruption before device application, and post ligaments were also transected with the osteotome via
device application. Axial images were generated with the Pfannenstiel incision. This combination of disrup-
reference to the perpendicular to the sacrum, while tion and injury complete the criteria for an APC III

JETT as a Pelvic Binder 31