Page 96 - JSOM Fall 2023

FIGURE 2. Civil War splints – Examples from the U.S. Civil War FIGURE 3. The Thomas Splint – The Thomas Splint consists of a
of simple prefabricated splints made from hand-formed wooded semicircular padded bar designed to sit on the ischial tuberosity
sections that would be strapped to the injured lower extremity. (bony prominence on the posterior of the pelvis) with a belt that
secures it to the proximal thigh. Two rigid bars protrude distally
to stabilize the limb and allow traction to be applied off the distal
aspect of the splint. This example is from World War I and does not
show the straps used to stabilize the limb and pull the limb distally to
provide traction.

take the longest to apply, as the materials often take up to 30
minutes to set properly. Application time for prefabricated
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air bladder-based splints is suspected to be low based on their
simple design but has not yet been published. Importantly,
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analyses of splint applications do not routinely include other
aspects of splint placement, such as positioning for application
and unpacking. In total, splinting adds an estimated 1.8 to 9
have active muscle control, meaning the differences could be minutes to the prehospital scene time if statistics from civil-
from a live human shifting around. Differences in producing ian settings are extrapolated to other contexts. 38,39 However,
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successful traction may be due to the training and experience the additional time to apply a splint on the battlefield or in
of the personnel applying the devices or to differences in de- an austere environment may vary even more, depending on
sign and application techniques. the terrain, tactical situation, weather, and personnel avail-
able to assist. Thus, splint application time must be balanced
In instances in which traction is contraindicated, such as crush with considerations such as field expediency and the ability
injuries that may result in compartment syndrome, field medi- to improve casualty or unit mobility. Future research should
cal personnel may employ a simple “box splint” design. His- quantify the total time to apply and use a splint system, not
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torically, this was performed by strapping an injured extremity just application time, to give rescuers a better estimate of time
to a piece of wood (Figure 2). More recently, the SAM splint, factors associated with splint utilization.
developed during the Vietnam War, consists of a sheet of pad-
ded aluminum that can be hand-formed around the injured The ease of which medical personnel can confidently use and
anatomy (Figure 1B). Air splints employ air-filled bladders for apply a splint may influence its battlefield or remote applica-
customizable levels of pressure and thus fracture stabilization tion success. Intuitively, designs that model simplicity by way
at the injury site. Vacuum splints involve a vinyl envelope of fewer parts and an obvious application procedure should
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filled with small individually-compressible balls of material perform favorably. In general, traction splint designs with one
(e.g., polystyrene) that stabilize a fracture and may provide rigid component (unipolar) outperform their bipolar coun-
structural stability via “granular jamming” (compression of terparts in subjective ratings of application confidence, pre-
granular materials within the apparatus when negative pres- application handling, and appropriateness for battlefield use.
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sure is applied) (Figure 1C). 34–36 Vacuum splints are light and Nevertheless, several designs have issues that limit their utility
compact; single splint options weigh between 0.2 to 1.0-kg, or safety. For example, the SAM splint consistently demon-
while a case of three splints and a portable vacuum pump weighs strated poor performance across metrics related to its success-
2.9-kg (EVAC-U-SPLINT , Hartwell Medical, Carlsbad CA, ful application despite its simple design. User concerns related
®
https://www.hartwellmedical.com/evac-u-splint-extremity to the SAM splint included poor protection of neurovascular
-splints/). structures, difficulty achieving and maintaining traction, and
excessive relative motion at the fracture site when compared
In-field application time is another important performance to other designs. These issues demonstrate that even simple
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metric and varies significantly between splint designs. For ex- designs such as the SAM splint require basic knowledge of
ample, an innovative spray-on foam splint provides the fastest human anatomy, structural design, and fabrication skills to
application time, taking just 68 seconds to apply to a simulated achieve an appropriately contoured safe application. In con-
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tibia fracture and an additional 60 seconds to cure. In con- trast, the spray-foam splint received high subjective ratings on
trast, the SAM splint requires an average of 203 seconds to reproducibility and ability for an untrained individual to apply
stabilize a simulated tibia fracture. Similar application times when compared to the SAM splint. 26
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were reported for the fiberglass wrap, FastSet3 (FareTec Inc.,
Painesville OH, https://www.faretec.com/), which reaches rigid- There are several limitations common to prefabricated splints
ity approximately 3 minutes after being activated by water and currently available for use in PCC and wilderness rescue scenar-
applied to the affected limb. Frame-based traction splints take ios. For example, in-field splinting has not enabled weight-bear-
upwards of 350 seconds to apply correctly to a more compli- ing or mobility post-application. Although air splints have been
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cated simulated injury, such as a femur fracture. Plaster splints designed to allow weight bearing after transtibial amputation,
94 | JSOM Volume 23, Edition 3 / Fall 2023