Myelopathy vs radiculopathy คือ

• summary

  • Cervical Myelopathy is a common form of neurologic impairment caused by compression of the cervical spinal cord most commonly due to degenerative cervical spondylosis.

  • The condition most commonly presents in older patients with symmetric numbness and tingling in the extremities, hand clumsiness, and gait imbalance. 

  • Treatment is usually surgical decompression and stabilization as the condition is associated with step-wise progression.

• Etiology

  • Pathophysiology

    • etiology

      • degenerative cervical spondylosis (CSM)

        • most common cause of cervical myelopathy

        • compression usually caused by:

          • osteophytes

          • discosteophyte complex

          • degenerative spondylolisthesis

          • hypertrophy of ligamentum flavum 

      • congenital stenosis

        • symptoms usually begin when congenital narrowing combined with spondylotic degenerative changes in older patients

      • OPLL

      • tumor

      • epidural abscess

      • trauma

      • cervical kyphosis

    • neurologic injury

      • mechanism of injury

        • direct cord compression

        • ischemic injury secondary to compression of anterior spinal artery

  • Associated conditions

    • lumbar spinal stenosis

      • tandem stenosis occurs in lumbar and cervical spine in ~20% of patients

• Classification of Myelopathy

  • Nurick Classification

    • based on gait and ambulatory function

  • Nurick Classification
    Grade 0	Root symptoms only or normal
    Grade 1	Signs of cord compression; normal gait
    Grade 2	Gait difficulties but fully employed
    Grade 3	Gait difficulties prevent employment, walks unassisted
    Grade 4	Unable to walk without assistance
    Grade 5	Wheelchair or bedbound

  • Ranawat Classification

  • Ranawat Classification
    Class I	Pain, no neurologic deficit
    Class II	Subjective weakness, hyperreflexia, dysesthesias
    Class IIIA	Objective weakness, long tract signs, ambulatory
    Class IIIB	Objective weakness, long tract signs, non-ambulatory

  • Japanese Orthopaedic Association Classification

    • A point scoring system (17 total) based on function in the following categories

      • upper extremity motor function

      • lower extremity motor function

      • sensory functionbladder function

    • Usually a significant improvement at 1-year postop, even in cases of severe myelopathy

• Presentation of Myelopathy

  • Symptoms

    • neck pain and stiffness

      • axial neck pain (often absent)

      • occipital headache common

    • extremity paresthesias

      • diffuse, bilateral, nondermatomal numbness and tingling

    • weakness and clumsiness

      • bilateral weakness and decreased manual dexterity (dropping object, difficulty manipulating fine objects)

    • gait instability

      • patient feels "unstable" on feet

      • weakness walking up and down stairs

      • gait changes are most important clinical predictor

    • urinary retention

      • rare and only appear late in disease progression

      • not very useful in diagnosis due to high prevalence of urinary conditions in this patient population

  • Physical exam

    • motor

      • weakness

        • usually difficult to detect on physical exam

        • lower extremity weakness is a more concerning finding

      • finger escape sign

        • when patient holds fingers extended and adducted, the small finger spontaneously abducts due to weakness of intrinsic muscle

      • grip and release test

        • normally a patient can make a fist and release 20 times in 10 seconds. myelopathic patients may struggle to do this

    • sensory

      • proprioception dysfunction

        • due to dorsal column involvement

        • occurs in advanced disease

        • associated with a poor prognosis

      • decreased pain sensation

        • pinprick testing should be done to look for global decrease in sensation or dermatomal changes

        • due to involvement of lateral spinothalamic tract

      • vibratory changes are usually only found in severe case of long-standing myelopathy

    • upper motor neuron signs (spasticity)

      • hyperreflexia

        • may be absent when there is concomitant peripheral nerve disease (cervical or lumbar nerve root compression, spinal stenosis, diabetes)

      • inverted radial reflex

        • tapping distal brachioradialis tendon produces ipsilateral finger flexion

      • Hoffmann's sign

        • snapping patients distal phalanx of middle finger leads to spontaneous flexion of other fingers

        • most common physical exam finding

      • sustained clonus

        • > three beats defined as sustained clonus

        • sustained clonus has poor sensitivity (~13%) but high specificity (~100%) for cervical myelopathy

      • Babinski test

        • considered positive with extension of great toe

    • gait and balance

      • toe-to-heel walk

        • patient has difficulty performing

      • Romberg test

        • patient stands with arms held forward and eyes closed

        • loss of balance consistent with posterior column dysfunction

    • provocative tests

      • Lhermitte Sign

        • test is positive when extreme cervical flexion leads to electric shock-like sensations that radiate down the spine and into the extremities

• Evaluation

  • Radiographs

    • recommended views

      • cervical AP, lateral, oblique, flexion, and extension views

    • general findings

      • degenerative changes of uncovertebral and facet joints

      • osteophyte formation

      • disc space narrowing

      • decreased sagittal diameter

        • cord compression occurs with canal diameter is < 13mm

    • lateral radiograph

      • important to look for diameter of spinal canal

        • a Pavlov ratio of less than 0.8 suggest a congenitally narrow spinal canal predisposing to stenosis and cord compression

      • sagittal alignment

        • C2 to C7 alignment

          • determined by tangential lines on the posterior edge of the C2 and C7 body on lateral radiographs in neutral position

        • local kyphosis angle

          • the angle between the lines drawn at the posterior margin of most cranial and caudal vertebral bodies forming the maximum local kyphosis

    • oblique radiograph

      • important to look for foraminal stenosis which often caused by uncovertebral joint arthrosis

    • flexion and extension views

      • important to look for angular or translational instability

      • look for compensatory subluxation above or below the spondylotic/stiff segment

    • sensitivity/specificity

      • changes often do not correlate with symptoms

        • 70% of patients by 70 yrs of age will have degenerative changes seen on plain xrays

  • MRI

    • indications

      • MRI is study of choice to evaluate degree of spinal cord and nerve root compression

    • findings

      • effacement of CSF indicates functional stenosis

      • spinal cord signal changes

        • seen as bright signal on T2 images (myelomalacia)

        • signal changes on T1-weighted images correlate with a poorer prognosis following surgical decompression

      • compression ratio of < 0.4 carries poor prognosis

        • CR = smallest AP diameter of cord / largest transverse diameter of cord

    • sensitivity/specificity

      • has high rate of false positive (28% greater than 40 will have findings of HNP or foraminal stenosis)

  • CT without contrast

    • can provide complementary information with an MRI, and is more useful to evaluate OPLL and osteophytes

  • CT myelography

    • more invasive than an MRI but gives excellent information regarding degrees of spinal cord compression

    • useful in patients that cannot have an MRI (pacemaker), or have artifact (local hardware)

    • contrast given via C1-C2 puncture and allowed to diffuse caudally, or given via a lumbar puncture and allowed to diffuse proximally by putting patient in trendelenburg position.

  • Nerve conduction studies

    • high false negative rate

    • may be useful to distinguish peripheral from central process (ALS)

• Differential

  • Normal aging

    • mild symptoms of myelopathy often confused with a "normal aging" process

  • Stroke

  • Movement disorders

  • Vitamin B12 deficiency

  • Amyotrophic lateral sclerosis (ALS)

  • Multiple sclerosis

• Treatment

  • Nonoperative

    • observation, NSAIDs, therapy, and lifestyle modifications

      • indications

        • mild disease with no functional impairment

          • function is a more important determinant for surgery than physical exam finding

        • patients who are poor candidates for surgery

      • modalities

        • medications (NSAIDS, gabapentin)

        • immobilization (hard collar in slight flexion)

        • physical therapy for neck strengthening, balance, and gait training

        • traction and chiropractic modalities are not likely to benefit and do have some risks

        • be sure to watch patients carefully for progression

      • outcomes

        • improved nonoperative outcomes associated with patients with larger transverse area of the spinal cord (>70mm2)

        • some studies have shown improvement with immobilization in patients with very mild symptoms

  • Operative

    • surgical decompression, restoration of lordosis, stabilization

      • indications

        • significant functional impairment AND

        • 1-2 level disease

        • lordotic, neutral or kyphotic alignment

      • techniques

        • appropriate procedure depends on

          • cervical alignment

          • number of stenotic levels

          • location of compression

          • medical conditions (e.g., goiter)

        • treatment procedures include (see below)

          • anterior cervical diskectomy/corpectomy and fusion

          • posterior laminectomy and fusion

          • posterior laminoplasty

          • combined anterior and posterior procedure

          • cervical disk arthroplasty

      • outcomes

        • prospective studies show improvement in overall pain, function, and neurologic symptoms with operative treatment

        • early recognition and treatment prior to spinal cord damage is critical for good clinical outcomes

      • goals

        • prevention of continued neurologic decline

• Techniques

  • Goals

    • optimal surgical treatment depends on the individual. Things to consider include

      • number of stenotic levels

      • sagittal alignment of the spine

      • degree of existing motion and desire to maintain

      • medical comorbidities (eg, dysphasia)

        • simplified treatment algorithm

  • Anterior Decompression and Fusion (ACDF) alone

    • indications

      • mainstay of treatment in most patients with single or two-level disease

      • fixed cervical kyphosis of > 10 degrees

        • anterior procedure can correct kyphosis

      • compression arising from 2 or fewer disc segments

      • pathology is anterior (OPLL, soft discs, disc osteophyte complexes)

    • approach

      • uses Smith-Robinson anterior approach

    • decompression

      • corpectomy and strut graft may be required for multilevel spondylosis

        • two level corpectomies tend to be biomechanically vulnerable (preferable to combine single level corpectomy with adjacent level diskectomy)

        • 7% to 20% rates of graft dislodgement with cervical corpectomy with associated severe complications, including death, reported.

    • fixation

      • anterior plating functions to increase fusion rates and preserve position of interbody cage or strut graft

    • pros & cons

      • advantages compared to posterior approach

        • lower infection rate

        • less blood loss

        • less postoperative pain

      • disadvantages

        • avoid in patients with poor swallowing function

  • Anterior corpectomy and fusion (ACF)

    • indications

      • extensive retrovertebral disease

      • cervical kyphosis preventing from adequate decompression posteriorly

    • technique

      • anterior fixation alone

        • amenable in up to 2-level corpectomy

        • use of static anterior cervical plate with struct graft

      • combined anterior and posterior fixation

        • indicated in 3-level corpectomy and above

        • use of anterior strut graft and plating combined with posterior lateral mass screw construct

        • anterior fixation alone in 3-level and aboveresults in a high (>70%) catastrophic failure rate

  • Laminectomy with posterior fusion

    • indications

      • multilevel compression with kyphosis of < 10 degrees

        • > 13 degrees of fixed kyphosis is a contraindication for a posterior procedure

      • in flexible kyphotic spine, posterior decompression and fusion may be indicated if kyphotic deformity can be corrected prior to instrumentation

    • contraindications

      • fixed kyphosis of > 10 degrees is a contraindication to posterior decompression

      • will not adequately decompress spinal cord as it is "bowstringing" anterior

    • pros & cons

      • fusion may improve neck pain associated with degenerative facets

      • not effective in patients with > 10 degrees fixed kyphosis

  • Laminoplasty

    • indications

      • gaining in popularity

      • useful when maintaining motion is desired

      • avoids complications of fusion so may be indicated in patients at high risk of pseudoarthrosis

      • congenital cervical stenosis

    • contraindications

      • cervical kyphosis

        • > 13 degrees is a contraindication to posterior decompression

        • will not adequately decompress spinal cord as it is "bowstringing" anterior

      • severe axial neck pain

        • is a relative contraindication and these patients should be fused

    • technique

      • volume of canal is expanded by hinged-door laminoplasty followed by fusion

        • usually performed from C3 to C7

      • open door technique

        • hinge created unilateral at junction of lateral mass and lamina and opening on opposite side

        • opening held open by bone, suture anchors, or special plates

      • French door technique

        • hinge created bilaterally and opening created midline

    • pros & cons

      • advantages

        • allows for decompression of multilevel stenotic myelopathy without compromising stability and motion (avoids postlaminectomy kyphosis)

        • lower complication rate than multilevel anterior decompression

          • especially in patients with OPLL

        • a motion-preserving technique

          • pseudoarthrosis not a concern in patients with poor healing potential (diabetes, chronic steroid users)

        • can be combined with a subsequent anterior procedure

          • combined laminoplasty with fusion has theoretical benefit of decreased muscular atrophy and preserved muscle attachments

      • disadvantages

        • higher average blood loss than anterior procedures

        • postoperative neck pain

        • still associated with loss of motion

    • outcomes

      • equivalent to multilevel anterior decompression and fusion

  • Combined anterior and posterior surgery

    • indications

      • multilevel stenosis in the rigid kyphotic spine

      • multi-level anterior cervical corpectomies

      • postlaminectomy kyphosis

  • Occipitocervical fusion

    • indications

      • periodontoid pannus

    • posterior-only occipitocervical fusion is safe and effective in promoting pannus resolution

    • transoral approaches are associated with increased morbidity, especially when surgical time exceeds 4 hours

  • Laminectomy alone

    • indications

      • rarely indicated due to risk of post-laminectomy kyphosis

    • pros & cons

      • progressive kyphosis

        • 11 to 47% incidence if laminectomy performed alone without fusion

• Complications

  • Surgical Infection

    • higher rate of surgical infection with posterior approach than anterior approach

  • Pseudoarthrosis

    • incidence

      • 12% for single level fusions, 30% for multilevel fusions

    • treatment

      • treat with either posterior wiring or plating or repeat anterior decompression and plating if patient has symptoms of radiculopathy

  • Postoperative C5 palsy

    • incidence

      • reported to occur in ~ 4.6% of patients after surgery for cervical compression myelopathy

        • higher incidence reported in males

      • no significant differences between patients undergoing anterior decompression and fusion and posterior laminoplasty

        • higher rates reported following posterior laminectomy and fusion

      • occurs immediately postop to weeks following surgery

    • mechanism

      • mechanism is controversial

      • in laminectomy patients, it is thought to be caused by tethering of nerve root with dorsal migration of spinal cord following removal of posterior elements

      • some studies suggest that prophylactic bilateral keyhole foraminotomies at the C4/5 level may help reduce the incidence of this complication

    • prognosis

      • patients with postoperative C5 palsy generally have a good prognosis for functional recovery, but recovery takes time

      • prolonged recovery associated with:

        • multilevel paresis

        • motor grade ≤2

        • sensory involvement with intractable pain

  • Recurrent laryngeal nerve injury

    • approach

      • in the past it has been postulated that the RLN is more vulnerable to injury on the right due to a more aberrant pathway

        • recent studies have shown there is not an increased injury rate with a right sided approach

      • prolonged retractor placement at the tracheoesophageal junction places RLN at risk for injury 

    • treatment

      • if you have a postoperative RLN palsy, watch over time

      • if not improved over 6 weeks, then ENT consult to scope patient and inject teflon

      • if you are performing revision anterior cervical surgery, and there is an any suspicion of a RLN from the first operation, obtain ENT consult to establish prior injury

        • if patient has prior RLN nerve injury, perform revision surgery on the same as the prior injury/approach to prevent a bilateral RLN injury

  • Hardware failure and migration

    • 7-20% with two level anterior corpectomies

    • two-level corpectomies should be stabilized from behind

  • Postlaminectomy kyphosis

    • treat with anterior/posterior procedure

  • Postoperative axial neck pain

  • Vertebral artery injury

  • Esophageal Injury

  • Dysphagia & alteration in speech

    • Multiple studies have demonstrated the application of local steroid in retropharyngeal space prior to wound closure decreases rate of dysphagia

  • Epidural hematoma

    • rare complication

      • 1:1000 incidence

    • associated with post-operative motor weakness and parasthesias

    • emergent MRI and hematoma evacuation

      • early evacuation results in better neurologic recovery

    • MRI appearance of hematoma depends on age

      • hyperacute (<24 hours):

        • hyperintense T2, hypointense T1

• Prognosis

  • Natural history

    • tends to be slowly progressive and rarely improves with nonoperative modalities

    • progression characterized by steplike deterioration with periods of stable symptoms

  • Prognostic variable

    • early recognition and treatment prior to spinal cord damage is critical for good clinical outcomes

CPT Codes: 62005, Elevation of depressed skull fracture; compound or comminuted, extradural 23615, Open treatment of proximal humeral (surgical or anatomical neck) fracture, includes internal fixation, when performed, includes repair of tuberosity(s), when performed; 23616 Open treatment of proximal humeral (surgical or anatomical neck) fracture, includes internal fixation, when performed, includes repair of tuberosity(s), when performed; with proximal humeral prosthetic replacement

Anterior Cervical Diskectomy and Fusion with Plate and Peak Cage (ACDF)

• Spine
• - Cervical Radiculopathy