Page 90 - Journal of Special Operations Medicine - Winter 2016

An Ongoing Series

Load Carriage–Related Paresthesias

Part 1: Rucksack Palsy and Digitalgia Paresthetica

Joseph J. Knapik, ScD; Katy Reynolds, MD; Robin Orr, PhD; Rodney Pope, PhD

ABSTRACT
This is the first of a two-part article discussing load- Introduction
carriage–related paresthesias, including brachial plexus Paresthesias are sensations of numbness, burning, and/
lesions (rucksack palsy), digitalgia paresthetica, and me- or tingling, usually experienced as a result of nerve in-
ralgia paresthetica. Paresthesias are sensations of numb- jury or irritation. Several types of compression- and
1
ness, burning, and/or tingling, usually experienced as a traction-related paresthesias have been described in as-
result of nerve injury, compression, traction, or irrita- sociation with load carriage, including rucksack palsy
tion. Rucksack palsy is a traction or compression injury (brachial plexus lesion), digitalgia paresthetica, and me-
to the brachial plexus, caused by the shoulder straps of ralgia paresthetica. These are important to understand
the rucksack. The patient presents with paresthesia, pa- in the military context because Soldiers involved in car-
ralysis, cramping with pain, and muscle weakness of the rying heavy loads and wearing body armor may present
upper limb. Muscle-strength losses appear to be greater with symptoms indicative of these types of injuries and
in those carrying heavier loads. Hypothetical risk fac- there may be long-term sequelae that could affect Sol-
tors for rucksack palsy include improper load distribu- dier and unit effectiveness.
tion, longer carriage distances, and load weight. Nerve
traction, compression, and symptoms may be reduced This is the first of a two-part article that will address
by use of a rucksack hip belt; wider, better-padded, and the symptoms, diagnosis, treatment, and prevention of
proper adjustment of the shoulder straps; reduction load-carriage–related paresthesias. Part 1 covers ruck-
of weight in the rucksack; a more symmetric distribu- sack palsy and digitalgia paresthetica. In Part 2, to be
tion of the load; and resistance training to improve the published in the next issue of the Journal of Special
strength and hypertrophy of the shoulder muscles. As- Operations Medicine, we will examine meralgia pares-
sessment and neck joint and nerve mobilization may thetica in detail.
relieve brachial plexus tension and reduce symptoms.
Another load-carriage–related disorder is digitalgia par- Brachial Plexus Lesion (Rucksack Palsy)
esthetica, likely caused by compression of the sensory A brachial plexus lesion is a disabling injury that has
digital nerves in the foot during load carriage. Patients been widely reported in association with load car-
have paresthesia in the toes. Although no studies have riage. 2–11 In early case studies, the malady was termed
demonstrated effective prevention measures for digital- “pack palsy” or “rucksack palsy” because it occurred
gia paresthetica, reducing loads and march distances in association with carrying heavy rucksacks. 4,12–14 It
may help by decreasing the forces and repetitive stress is more common in military personnel 3,4,6–10,12–18 but
on the foot and lower leg. Specialty evaluations by a has also been reported in association with recreational
physical therapist, podiatrist, or other healthcare pro- backpacking. 11,19–21 Reported incidences were 5.6 cases
vider are important to rule out entrapment neuropathies per 10,000 recruits per year in US Army basic training,
3
such as tarsal tunnel syndrome. Part 2 of this article will 5.4 cases per 10,000 recruits per year in Finnish basic
discuss meralgia paresthetica.
training, 9,17 and 3.0 cases per 10,000 recruits per year in
South Korean basic training. Data we obtained from
18
Keywords: load-carriage–related paresthesia; brachial plexus the Defense Medical Epidemiology Database indicated
lesion; rucksack palsy; digitalgia paresthetica; nerve compres- that the incidence for brachial plexus lesions (Interna-
sion; load distribution
tional Classification of Diseases, ninth edition, code
353.0) was 22.2 per 10,000 Soldiers per year in 2006

74