Page 91 - JSOM Fall 2022

Pathophysiology He also reported noticing spasms in the left upper extremity
while running, including involuntary contracture of the pinky
In a healthy adult, the cervical canal varies in diameter with and left pinky finger. His review of systems revealed an occa­
normal anatomic variation, craniocaudal level of the spine, and sional headache lasting 30 minutes to 6 hours, localized over
range of motion. It is widest at the levels C1 to C3, normally the occipital region. His past medical history at the time was
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between 16 to 30 mm in anteroposterior (AP) diameter. This significant for cervical spondylosis two years ago, that mani­
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space decreases to a range of 14–23 mm at levels of C4–C7. fested during basic combat training as left shoulder and non­
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The most likely location of DCM to occur is at the level of the specific left arm paresthesia when performing push­ups. At the
C7 vertebrae; however, it is not clear if this is simply because it time, magnetic resonance imaging (MRI) of the cervical spine
is where the AP diameter is smallest or if other biomechanical demonstrated a C3/C4 mild broad­based disc bulge, mild
factors contribute to this. Generally, the AP diameter of the acquired spinal canal stenosis with mild left neuroforamen
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cervical canal narrows by 2–3 mm with extension of the cer­ stenosis without nerve root encroachment; C4/C5 left para­
vical column. Varying degrees of congenital cervical stenosis central disc protrusion with annular tear; moderate acquired
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of the spinal canal can decrease the AP diameter even further. 4 spinal canal stenosis; moderate left neural foramen stenosis
and mild right neural foramen stenosis with left nerve root
Numerous soft­tissue and bony structures surround the spi­ encroachment. He was managed conservatively with eight
nal canal. Posterior to the spinal canal lies the ligamentum sessions of targeted physical therapy and activity restriction.
flavum. Anterolateral to the spinal canal lie the zygapophy­ He reports that although his symptoms did not completely
seal (ZPJ) and uncovertebral joints (UVJ). Anterior to the spi­ abate, he achieved enough relief and functional improvement
nal canal lies the posterior longitudinal ligament (PLL), with that he was able to complete basic training and advanced in­
the intervertebral disc anterior to it. Degenerative changes in dividualized training as a field artilleryman. He reports that
any of these structures contribute to cervical spondylosis and he was minimally symptomatic up through the presenting
eventual myelopathy. Repetitive mechanical stress leads to complaint’s timeframe. He states that he was able to perform
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degenerative changes and compensatory mechanisms for these his duties as required, which involved carrying a full fighting
changes. This leads to osteophyte formation at the ZPJ and load, routinely lifting 80–120 lb. His other duties, pertinent to
UVJ, with stiffening, thickening, and ossification of the PLL. 10 his history, included operating and riding in a high mobility
multipurpose wheeled vehicle (HMMWV). He reported a one­
The final common pathway is mechanical compression and pack every 2–4 weeks smoking history for about 2 years. His
irritation of the spinal dura, the contained spinal cord, and the neurological exam was profoundly remarkable for cervical ra­
microvasculature. Disruption of the dura leads to the cord diculopathy. He had left hypothenar atrophy with respect to
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being susceptible to peripheral inflammatory chemokines. the right side. He had decreased sensation over the C5 and C6
These chemokines may be present as a result of degeneration dermatomes. Biceps reflexes on the left were 3+, compared to
of surrounding structures. Studies on rat models also demon­ 2+ on the right side. He had 4/5 strength with elbow flexion.
strate increased cord inflammatory states with activation of The patient was placed on heavy duty restriction, protecting
the cord­specific CXCR3 chemokine receptors, which cor­ him from high­impact aggravating activities and increased
relates to decreased neurological function. Compression of axial loading. Given his past history of cervical canal steno­
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the microvasculature results in endothelial disruption and hy­ sis and aforementioned radicular signs, a cervical spinal MRI
poxic states of the spinal cord. This leads to eventual apoptosis without contrast was ordered and performed about 3 weeks
of microglia and neurons, the latter lacking progenitor­based later. The MRI revealed right paracentral disc protrusion that
regeneration potential. 10 was contacting and flattening the cervical cord at the level of
C3/C4, along with fluid surrounding the cord; a broad disc
Disruption or destruction of the cord leads to decreased signal osteophyte complex at the C4/C5, filling the left paracentral
transduction and manifests as radicular signs and symptoms. and left lateral recess, distorting the contour, and flattening
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Unlike nerve root compression, which manifests as single­level and displacing the cord; and an osteophyte on the right at the
radiculopathy, DCM can lead to paresthesia and paralysis of same level causing advanced canal and bilateral foraminal nar­
all structures caudal to the area of insult. Furthermore, DCM rowing (Figures 1 and 2). The abnormal cord signal extended
at or above the level of C3 can lead to paralysis of the phrenic through the C5/C6 level, with canal narrowing through the
nerve, leading to respiratory failure. 10 C6/C7 level.

In the management of a patient with suspected DCM, a sys­ Consultation with neurosurgery was made through a private
tematic evaluation of the spinal cord is required. The Inter­ community hospital. The patient, with assistance of command,
national Standards for Neurological Classification of Spinal was brought to the TMC. After shared decision­making with
Cord Injury (ISNCSCI), published by the American Spinal In­ the patient and consultation with neurosurgery, the patient
jury Association (ASIA), colloquially referred to as the “ASIA was placed in a rigid cervical collar and transported to the
Spine Scale,” serves as a systematic tool for accomplishing accepting facility. Repeat examination was minimally changed
this, with high inter­ and intra­provider reliability. 11 from the previous visit. After evaluation by neurosurgery,
the patient underwent an uneventful C4/C5 fusion. Pre­ and
Case Presentation post­fusion films demonstrated a 300% disc height increase
of the C4/C5 intervertebral space (Figure 3). On postopera­
A 27­year­old male Army Soldier presented to the Troop Med­ tive day 1, the patient had resolution of previously described
ical Clinic (TMC) with a chief complaint of low back pain for hyperreflexia. He had improved strength at the previously de­
several weeks that is exacerbated with running and radiates scribed areas of weakness. At 4 weeks postoperatively, the pa­
to the posterior aspect of the left thigh. Upon further inter­ tient reported near­resolution of previously described occipital
view, he endorsed nonspecific upper extremity dysesthesias. headaches. With guided physical therapy over 8 weeks, the

Walking Quadriplegic | 87