Gait in Adult Patients With Cervical Spondylotic Myelopathy
Gait in Adult Patients With Cervical Spondylotic Myelopathy
The purpose of this study is to evaluate the effect of cervical decompression surgery on the
 biomechanics of the lower extremities and spine during balance and gait in patients with
 cervical spondylotic myelopathy (CSM), before and after surgical intervention, and compare
 these parameters to an asymptomatic control group. To test our hypothesis that cervical
 decompression will improve preexisting gait disturbance, a gait analysis using dynamic
 surface EMG, video motion capture, and force plate analysis will be used. Patients 30 to 70
 years old will be eligible for the study. Thirty subjects diagnosed with symptomatic CSM and
 are deemed appropriate surgical candidates, along with 30 healthy subjects with no spine
 pathology, will be enrolled in this study. Exclusion criteria include any history of previous
 lumbar/thoracic surgery or lower extremity surgery, BMI greater than 35, or currently
 pregnant. Each subject from the surgical group will be evaluated on 3 different occasions: 1)
 1 week before surgery, 2) 3 months postoperative, and 3) 12 months postoperative. Control
 subject will only be evaluated once. Bilateral trunk and lower extremity neuromuscular
 activity will be measured during a full gait cycle using dynamic surface EMG measurements.
 Human video motion capture cameras will collect lumbar spine and lower and upper extremity
 joint angles. Ground reaction forces (GRFs) will be collected from a 5 foot stretch of force
 platforms in order to define a full gait cycle.
Cervical spondylotic myelopathy (CSM) is a neurologic condition resulting from spinal cord
 compression caused by degenerative narrowing of the cervical spinal canal. CSM is most common
 after the age of 50 years, but the age of onset is variable depending on the degree of
 congenital spinal canal narrowing. Progressive degenerative changes in the cervical spine,
 such as disc bulges or herniations, facet hypertrophy, ligamentum flavum thickening, and
 degenerative vertebral spondylolisthesis, can all contribute to progressive spinal cord
 compression. The end result is chronic compression of the spinal cord and/or nerve roots
 leading to impaired blood flow, which can result in frank damage within the spinal cord
 itself. CSM is characterized by a wide variety of clinical presentations, which can include
 neck pain, numbness or weakness in the extremities, hand clumsiness, and, classically, gait
 disturbances. This typically manifests as difficulty with balance, but patients with more
 advanced myelopathy can also develop a stiff, spastic gait.

 Surgical treatment of CSM revolves around decompressing the spinal cord, either with or
 without concurrent fusion. Many surgical strategies have been proposed. Anterior surgical
 approaches include anterior cervical discectomy and fusion or anterior corpectomy and fusion.
 Posterior surgical approaches include laminectomy with or without fusion, or laminoplasty.
 The choice of surgical approach is specific to each patient based upon the extent and
 location of the pathology, the presence or absence of deformity or spinal instability, the
 sagittal alignment of the spine, the presence or absence of ossification of the posterior
 longitudinal ligament (OPLL), as well as other patient co-morbidity factors and surgeon
 preference. While there may be some debate as to when patients with radiographic cervical
 stenosis should undergo decompressive surgery, most surgeons would agree on surgery for
 patients with moderate or severe clinical myelopathy.

 Altered gait is frequently seen with CSM, and has been reported to be improved by surgical
 intervention. A stiff or spastic gait is also characteristic of CSM in its later stages. Many
 clinical studies have determined that patients with CSM have a slower gait speed, prolonged
 double support duration, and reduced cadence compared to healthy controls.Previous studies
 also identified reduced knee flexion during swing in the early stages of the disease, and, in
 more severe cases, decreased ankle plantar flexion at the terminal stance and reduced knee
 flexion during loading response.

 Upright stance and body stability depends on the vestibular, visual, and somatosensory
 systems.These systems contribute to the maintenance of postural control. The spinal cord,
 particularly the dorsal column, is an integral part of the somatosensory system.The dorsal
 columns relay the position and vibration sensations as well as play an important role in
 maintaining postural stability and conveying sensory information such as deep sensations to
 the lower limbs.When the dorsal column of the spinal cord is compressed, the functions of
 vibration sense, deep sensibility, and joint position sense are lost. CSM patients were found
 to have impaired knee proprioception when using electrogoniometer.22 A damaged spinal cord
 causes impaired body balance because of proprioceptive loss, and patients develop ataxia in
 the lower limbs.

 Jean Dubousset, first introduced the concept of the cone of economy and balance (COE) in
 1994. The COE refers to a stable region of standing posture. The fundamental assumption is
 that swaying outside one's individual cone challenges the balance mechanisms and expends
 critical energy. Balance is defined as the ability of the human body to maintain its center
 of mass within the base of support with minimal postural sway. Sway is the movement of the
 COM in the horizontal plane when a person is standing in a static position. Balance
 efficiency is defined as the ability of the patients to maintain their COM within the COE
 with minimal sway and energy expenditure.Maintenance of balance requires coordination between
 the sensorineural and musculoskeletal systems. Very few studies have looked at functional
 balance in CSM patients. These studies used a stabilometer to measure center of gravity.
 During a 30 seconds balance test with closed eyes, CSM patients swayed significantly more and
 had greater postural instability compared to healthy controls. Neither of those studies
 reported on neuromuscular activity during a functional balance test. Haddas et al.was first
 to introduce a method to objectively quantify the COE and neuromuscular energy expenditure
 during a dynamic balance test.

 There is very little literature investigating the effect of surgical intervention on a CSM
 patient's balance and gait using human motion analysis both before and after surgery. In
 fact, there have not been any studies examining how surgical intervention for CSM can improve
 patients' balance and gait utilizing objective neuromuscular data as well as full body
 kinematic analysis. Additionally, none of the previous studies have been able to validate
 self-reported pain and functional outcome measures utilizing a human motion capture system
 and EMG.

 This study explores the effect of CSM on human balance and gait and will utilize kinematic
 balance and gait analyses to examine the dynamic range of motion of the spine and lower
 extremities, along with neuromuscular data from surface EMG to precisely define the timing
 and degree of spine and lower extremity muscle activation and peak activity, as well as
 measurements of ground reaction forces throughout the gait cycle. All of this will be
 compared pre- and post-operatively and also with a healthy control group in order to
 determine the extent to which CSM affects the biomechanics of and neuromuscular control
 during balance and gait and how this changes after surgical intervention. We will also be
 able to correlate these objective measures with patient self-reported pain and function based
 on commonly used outcome instruments.

 In summary, the purpose of this study is to explore the level of functional compromise, both
 objectively and with patient-reported outcome measures, in patients with CSM and to quantify
 the possible benefit of surgical intervention on the biomechanics and neuromuscular control
 of the spine and lower extremities as evaluated by balance and gait analyses using dynamic
 EMG, video motion capture, force plate analysis, and validated patient-reported outcome
 metrics.
Inclusion Criteria:

 1. Age 30 years and older

 2. Diagnosis of CSM with correlative imaging studies (MRI or CT-myelogram)

 3. Able to ambulate without assistance and stand without assistance with participant eyes
 open for a minimum of 10 seconds

 4. Able and willing to attend and perform the activities described in the informed
 consent within the boundaries of the timelines set forth for pre-, and post-operative
 follow-up

 Exclusion Criteria:

 1. History of prior attempt at fusion (successful or not) at the indicated levels,
 (history of one level fusion is not an exclusion)

 2. Major lower extremity surgery or previous injury that may affect gait (a successful
 total joint replacement is not an exclusion)

 3. BMI higher than 35

 4. Neurological disorder (beside cervical spondylotic myelopathy), diabetic neuropathy or
 other disease that impairs the patient's ability to ambulate or stand without
 assistance

 5. Usage of blood thinners

 6. Pregnant or wishing to become pregnant during the study