Page 92 - Journal of Special Operations Medicine - Winter 2016

syndrome will involve the lower portion of the plexus. on the Appalachian Trail found that 8% (21 of 280
Physical therapy may reduce neural tension 25,26 and surveyed hikers) reported symptoms consistent with
help manage nerve compression from a thoracic outlet this disorder. A group of 30 Israeli Army recruits were
36
syndrome. 27 examined every 3 weeks during a 14-week basic train-
ing cycle and 14 (47%) were diagnosed by physicians
Use of a frame and hip belt has been demonstrated to as having digitalgia paresthetica. In this latter study,
32
reduce the incidence of rucksack palsy, presumably by nine recruits were followed up for 9 months after basic
3
reducing pressure on the shoulders. 28,29 Use of a properly training. Seven became asymptomatic and two remained
adjusted hip belt can remove 30% of the weight from symptomatic.
the shoulders. Soldiers should be asked if they are us-
28
ing their hip belts on their rucksacks; if they are not, The feet are at risk for compression neuropathies pre-
they should be encouraged to do so. sumably due to repetitive trauma associated with pro-
longed load carriage and/or possibly tight or poor-fitting
Other potential interventions to reduce the incidence of foot wear. Digital paresthetica is the term used when
brachial plexus palsy have not been specifically tested for the symptoms involve the toes, and is characterized by
their efficacy but may assist in primary or secondary in- paresthesias or dysthesias (burning), which may occur
jury prevention. If possible, reduction of the weight in at night. This condition is presumed to be associated
the rucksack will likely be helpful. Commanders should with a direct compression injury to the sensory nerves
encourage Soldiers to remove packs during rest periods innervating the feet and toes. Tarsal tunnel syndrome
where this is operationally viable. Periodic adjustment of is a neuropathy associated with the compression of the
the shoulder straps to distribute the load to different parts posterior tibial nerve and its branches in the tarsal tun-
of the shoulder will reduce pressures on any single part of nel. This symptom complex typically presents with par-
the shoulder while on the march. Wider shoulder straps esthesias and dysthesias along the inside ankle and the
will distribute the load over a great portion of the shoul- arch, and can occur at night. The tarsal tunnel neurop-
der, thus spreading the load over a larger surface area. athy may also cause symptoms in the toes. Potential
37
Improving the padding of the shoulder straps may also be causes of the compression neuropathies include overuse
helpful in reducing point pressures. Modifications of the or fatigue of lower-leg muscles 38–40 associated with long-
shoulder straps may not be possible or desirable among distance activity or in the early phases of an unaccus-
smaller Soldiers who have less acromial width and where tomed training program that may result in swelling in
the modified straps might compress the acromion pro- the tarsal tunnel or other areas of the feet. In the case of
cess and cause pain and potential shoulder impingement. Soldiers, compression of the nerves under the foot or in
Strengthening and hypertrophy of shoulder muscles may the tarsal tunnel is likely due to the repetitive loading of
provide a greater buffer between the rucksack shoulder the foot and lower-leg muscles from walking with heavy
straps and nerve tissue, improving shoulder stability to loads. 32,38 In one case study, compression was apparently
reduce brachial plexus strain, and better distribute the due to the toes being tightly squeezed by the boots the
load across a wider surface area of the shoulders, thus patient was wearing. Repetitive trauma and irritation
35
reducing point-compression of nerve tissue. of the interdigital nerves of the toes due to poorly fitting
footwear may lead to swelling and scarring around the
Research has shown that treatment from a physical ther- nerves, resulting in a neuroma. The term is known as
apist, involving specific exercises and manual therapy, Morton’s neuroma, which is associated with paresthe-
can reduce symptoms originating from the neck or bra- sias and dysesthesias of the involved toes. 37
chial plexus and nerve tension in the arm. 25,27,30,31 If pres-
ent, a cervical rib or more severe nerve entrapment or In the study involving the Appalachian Trail hikers,
compression due to thoracic outlet syndrome may have those experiencing digitalgia paresthetica had generally
to be treated by surgery to relieve the nerve compres- hiked for a greater number of days and for a longer dis-
sion, irritation, or tension. 27 tance than those without the condition. Military train-
36
ing in running shoes, as opposed to the normal Israeli
Digitalgia Paresthetica boot, had little influence on the incidence of digitalgia
Digitalgia paresthetica is another condition reported paresthetica (boot incidence, 50%; running shoe inci-
among those involved in load carriage. The condition dence, 43%; relative risk, 1.17; 95% confidence inter-
has been termed “marcher’s digitalgia paresthetica,” val, 0.54–2.54; p = .70). 32
presumably because of its occurrence among military
recruits involved in foot marching activities. The con- To our knowledge, there are no studies that examined
32
dition was first described in 1954, and since then, a preventive measures for digitalgia paresthetica. How-
33
few additional case studies have appeared in the litera- ever, reducing and more gradually progressing loads
ture. 34,35 A survey of hikers who spent 7 or more days and march distances may be effective, particularly in the

76 Journal of Special Operations Medicine Volume 16, Edition 4/Winter 2016