Page 74 - 2022 Spring JSOM

The amputations occurred at the Texas Tech Paul L. Foster FIGURE 1 Four tools used throughout the study without
School of Medicine Cadaver Lab in El Paso, Texas. Three resharpening.
adult cadavers were used for this study; they were approxi-
mately 1 month old, lightly embalmed, and studied while at
17°C (62°F). All limbs, bones, and soft tissues were untouched
by instrumentation before the experiment. The cadavers all
had normal anatomy without limb damage, prior injuries, or
surgeries to the extremities.

Amputation sites were distal and proximal long bones: tibia
and fibula, radius and ulna, humerus, and femur. A total of
36 amputations were attempted, 9 attempts with each knife.

The equipment selected to perform the amputations needed
to meet essential criteria: readily available, easily portable,
manually operated, and containing a straight knife edge and a
separate serrated sawing edge. Four tools were purchased at a
national outdoor supply store, representing a sample meeting
the selection requirements and the most common tool designs.

The tools selected all utilized stainless-steel metal, including a
Leatherman multitool, a Victorinox Swiss Army Rescue Tool
marketed to prehospital medical personnel, a TreeHopper
3-in-1 Field Dress Knife (a folding hunting knife), and a SOG
Pentagon fixed blade knife (Studies and Observations Group)
marketed to law enforcement and the military.
The Leatherman Super Tool 300 has a nonserrated knife and
a serrated saw blade 8 cm (3.2 in) in length. The Victorinox
Swiss Army Rescue Tool utilizes a serrated disc saw cutting
blade measuring 8 cm (3.15 in) and a nonserrated, wavy-edge
knife cutting blade. The Treehopper 3-in-1 Field Dress Knife
has a nonserrated knife blade and a serrated saw cutting blade with the straight edge and turned the knife 180 degrees to use
measuring 8.8 cm (3.5 in). All three of these foldable tools the serrated edge to saw through bone.
have locking blades. Finally, the SOG Pentagon outdoor dou-
ble-edge fixed blade (measuring 12.7 cm [5 in]) knife has a A digital timer was started when the blade contacted the skin,
straight edge and an opposite, beveled scalloped edge that and the amputator began the amputation. Once the limb was
does not have traditional saw teeth. The four tools were used amputated entirely from the body, the timer was stopped, and
throughout the study without resharpening (Figure 1). the time was recorded. The amputators were blinded to the
time. If the limb was not removed from the body within 2
Before amputation, the limb was secured in a vise by an as- minutes, the attempt was considered a failure, and a further
sistant to simulate entrapment. The amputation site was de- attempt was aborted. Tools and amputators were randomized
termined by measuring approximately 10 cm (4 in) from the using a simple computer research randomizer. Each amputator
nearest joint. Each cadaver had a distal and proximal limb had a 10-minute break between amputations to rest. All am-
amputation performed, progressing from distal to proximal. putators used each tool at least once.
The limb circumference was measured using a standard tape
measure and was recorded before amputation, and the diam- After all amputations were completed, each amputator com-
eter was calculated. A tourniquet was not used because of the pleted a questionnaire discussing their subjective experience
inability to establish functionality on a cadaveric specimen. with each tool. The amputators ranked the tools from 1 to
The amputators wore complete medical personal protection 4 based on their interpretation of an actual field amputation
equipment. scenario. A ranking of 1 indicated the most preferred tool,
and 4 indicated the least preferred tool. These numbers were
The amputation method chosen was based on the disaster or averaged. A score closer to 1 indicates a more preferred tool,
11
wartime open circular guillotine amputation technique. Each while a score of 4 indicates a less preferred tool.
amputator was instructed to cut through the skin, fascia, and
muscle tissue with the nonserrated knife blade, then switch to Data were collected, and means, standard deviation (SD), and
a serrated saw blade to cut through the bone, disengaging the t-test performed using a computerized spreadsheet (Microsoft
extremity from the body. For the three folding tools, the am- Excel for Mac). Kruskal-Wallis tests were used for the analysis
putator initially started with the straight edge blade exposed. of subjective data.
Once the soft tissue was cut through, the amputator retracted
the straight edge blade and exposed the serrated blade to saw
through bone. The SOG knife is designed as a single fixed Results
blade with a straight edge and an opposing serrated edge. Us- The times for amputation and success/failure of the four
ing the SOG knife, the amputator cut through the soft tissue amputation tools are summarized in (Table 1). The highest

72 | JSOM Volume 22, Edition 1 / Sping 2022