Cervical Degeneration

Cervical Myelopathy

DefinitionCervical Myelopathy MRI


Spinal cord dysfunction
- extrinsic compression of the cord or its vascular supply
- caused by degenerative disease of spine




Most common spinal cord dysfunction in patients > 55 years old

C5/6 commonest level




- congenital / developmental stenosis
- decreased space available for cord
- average mid cervical spine is 17 – 18 mm



1. HNP

2. Osteophytes from facet and uncovertebral joints
3. Ligamentum Flavum

4. Instability

5. Kyphosis
- stretches spinal cord over posterior vertebral bodies and discs
- dictates an anterior approach

6. Ossification of PLL
- more common in certain Asian populations i.e. Japanese



Need to exclude other causes of spinal cord dysfunction


- CVA / AVM / Tumour / Hydrocephalus

- Metabolic or alcoholic encephalopathy


- demyelinating disease / MS / MND
- syringomyelia / Tabes dorsalis

- myopathy / peripheral neuropathy




Neck pain


- global, non dermatomal distribution over upper extremities


Difficulty walking / unsteadiness on feet



- have central cord like presentation
- distal worst than central


- pain , numbness and weakness
- clumsiness of hands common
- difficulty with fine motor function
- may also have radicular symptoms


Bladder dysfunction uncommonly occurs


May present acutely with central cord syndrome




UMN in extremities below lesion

LMN signs at level of lesion




Wide based gait

Unable to heel toe


Poor proprioception

1.  Finger escape sign
- deficient adduction or extension of ulnar digits of affected hand


2.  Romberg Positive




1.  Hoffman Reflex
- flexion of ipsilateral IPJ of index and thumb when long finger DIPJ flexed

- extension of neck increases sensitivity


2.  Inverted Brachioradial Reflex

- spontaneous flexion of digits when BR reflex elicited
- indicates cord compression at C5 and C6 / commonest levels


3.  Babinski Reflex



Narrowed joint space
- C5/6 commonest level followed by C6/7


Osteophytic lipping
- foraminal and uncovertebral osteophytes seen


- lordosis v kyphosis

Cervical Stenosis Kyphotic AlignmentLordotic Cervical SpineCervical Spinal Kyphosis Flexion View


Ossification PLL


Cervical Spine OPLL


Flexion / Extension views show instability
- > 3 o
- > 11 mm


Pavlovs Ratio
- AP diameter of spinal canal divided by the AP diameter of body at same level
- indicator of developmental stenosis
- should be 1.0

- < 0.8 is narrowed and stenotic


AP diameter / SAC
- normal (17mm)
- relative (13mm)
- absolute stenosis (10mm)


NB: X-ray estimates of space available for cord

- do not take into account ST i.e. discs and ligamentum flavum




Helps distinguish disc from osteophytes

- soft v hard disc




OPLL Cervical Spine




Disc herniation

- high incidence of asymptomatic findings
- 19% of asymptomatic patients have abnormality on MRI


Cervical Myelopathy Herniated Discs


Cord changes
- cord oedema with signal change seen


Cervical Myelopathy Cord Changes


AP diameter thecal sac < 10 mm


Compression Ratio
- banana cord
- divide the smallest AP diameter by largest transverse diameter at same level of spinal cord
- ratio of < 0.4 after decompression particularly with myelopathy > 6 months has poor prognosis


Cervical Myelopathy Compression Cord Ratio


Cross sectional area of spinal cord
- < 30 mm2 poor prognosis




Natural history suggests that > 50% of patients become worse if not treated
- some stable
- most slowly progressive
- < 5% acute deterioration




Non operative


Cervical collar
Physiotherapy with isometric strengthening
Ice , heat and massage

Follow up every 6-12 weeks initially followed by yearly if no progression

Traction and manipulation contraindicated

Must counsel them to the risks of trauma




Absolute Indications


1. Progressive neurological deficit
2. Failure of symptoms to improve with 6 months of non operative treatment
- base on severity of clinical neurological fingings


Relative indications


1. Compression ratio < 0.4
2. Transverse spinal cord diameter of < 40 mm2
3. Increased signal intensity of cord on T2 of MRI
4. Acute central cord syndrome
- initially collar and methylprednisolone
- no operation if near full recovery
- decompress if residual neurological deficit




The patient with cervical and lumbar stenosis

- should have the cervical spine decompressed first

- risk of intubation damage to cervical spine
- reduces need for lumbar surgery
- leg symptoms may improve after the cervical decompression




Surgery can be expected to halt progression

- may improve motor, sensory and gait disturbance


The best spinal cord recovery seen in those treated
- decompression within 6 - 12 months
- early, mild myelopathic signs
- transverse area of cord greater than 40 mm2 postoperatively
- age < 60


Preoperative Considerations


NSAIDS ceased 2 weeks prior to surgery


Positioning should avoid hyperextension of the cervical spine

- may need awake fibreoptic intubation




1.  Laminectomy & fusion

2.  Laminoplasty

2.  ACDF

3.  Corpectomy


1. Laminectomy & Fusion


Cervical Myelopathy Posterior Decompression InstrumentedCervical Myelopathy Posterior Decompression Instrumentation




Any posterior decompression procedure is an indirect technique

- requires posterior shifting of the cord in the thecal sac

- to diminish the effect of the anterior compression



Lordotic cervical spine / no kyphotic deformity

Ossification of PLL

- dura may be adhered

- high risk of irreparable dural tears with anterior approach


Indications for fusion





Positioning for the posterior approach
- prone
- Mayfield head tongs in neutral

- protect eyes / elbows (ulna nerve) / knees (CPN)
- pneumatic compression stockings
- infiltration of skin with adrenaline solution



- wide laminectomy +/- foraminotomy


- avoids progressive kyphotic deformity
- lateral mass screws


Cervical Myelopathy Posterior Decompression




Postoperative instability / kyphosis
- > 50% facet resection = instability
- avoid by fusion or laminoplasty


2.  Laminoplasty



- divide lamina unilaterally

- elevate to decompress

- insert device to keep lamina elevated



- maintains stability

- no need to insert pedicle screws



- no kyphotic deformity


3. ACDF / Corpectomy and Arthrodesis





- anterior cord compression

- pathology primarily at disc level

- kyphotic deformity


removes entire disc

- can maintain / restore lordosis

- restores foramina / decompresses nerve root


- difficulty decompressing the nerve roots in foramen from front
- difficult access to the posterior osteophytes




Smith - Robinson approach


- supine with interscapular roll
- head turned slightly to right for left sided approach


Disc removal in full
- MRI reviewed carefully to exclude free disc lying behind the PLL
- resect the disc until the longitudinal fibres of PLL seen

- inspect carefully for defect
- if no defect on MRI findings then should not routinely remove the PLL


Insertion cage 

- contains autograft / allograft / BMP & collagen
- sized first, check on x-ray
- insert cage, ensuring not too posterior
- aiming to decompress foramina


Anterior plate for stability


4.  Corpectomy and strut Graft





- multilevel disease

- soft and hard disc causing compression

- kyphotic deformity




Anterior approach
- decompression of disc above and below

- resection of vertebral body with burr
- leave lateral walls to protect vertebral artery
- typical midline channel is 16 – 18 mm


Bone Grafting Technique
- single level, iliac crest
- multiple level, fibular strut
- autograft superior to allograft


- maintains alignment / improves graft stability

Post op
- usually require HTB




1. Transient sore throat or difficulty swallowing

- most common complication

- superior laryngeal nerve


2. Recurrent Laryngeal Nerve paralysis
- more common in right sided approach
- post operative hoarseness


3. Respiratory compromise
- drains
- strict monitoring

- emergency release of wound stitches if haematoma


4. Neurological injury 1 – 2%


5. Injury vertebral artery


6. Dural tears
- more common if OPLL
- fibrin glue, fascial patch


7. Graft related
- dislodgement
- fracture
- severe settling
- pseudoarthrosis

Cervical Radiculopathy



Clinical diagnosis

- based on a sclerotomal distribution of motor &/or sensory symptoms or signs


Caused by impingement of exiting nerve roots


- zygo-apophyseal / facet joint hypertrophy

- neuro-central joint hypertrophy


May be acute or chronic






Peak age 50-54


C7 > C6


Natural History


Mayo Clinic Natural History Radiculopathy

- 50% of population at some stage

- ~50% recurrent

- 90% asymptomatic at 5 years




Each subaxial C-spine motion segment has 5 articulations


A. Intervertebral disc


B.  2 neurocentral / uncovertebral joints

- along posterolateral vertebral body / Joint of Luschka

- lie between disc & nerve root

- each body has upturned postero-lateral uncinate process

- pedicle is attached below uncinate process


C.  2 facet joints

- angulated 30-50° to transverse plane


Intervertebral foramina boundaries


A. Anterior

- both vertebral bodies, uncinate process & disc


B.  Posterior

- facet joints


C.  Above & below

- pedicles


Foramina are 45° to sagittal plane


Transverse process


3 elements

1. Embryological TP to posterior tubercle

2. Embryological rib to anterior tubercle

3. Tubercles joined by intertubercular lamella


Foramen transversarium in middle with vertebral artery

Dorsal root ganglion and ventral ramus spinal nerve on intertubercular lamella




Posterior tubercle

- Scalenus medius


Anterior tubercle

- Scalenus anterior, longus coli & capitus

- progressively enlarge from C3 down to C6

- C6 Chassaignacs tubercle


Cervical Nerve Roots


Each cervical root exits above the pedicle for which it is named except C8

- C5/6 – C6

- C6/7 – C7

- C7/T1 – C8


Pathophysiology Nerve root compression


1.  HNP

- in contrast to lumbar spine

- both posterolateral and central HNP compress exiting nerve root

- inflammatory and ischaemic components


A. Central - myelopathy

B. Posterolateral - mainly motor weakness

C. Intraforaminal - most common / often dermatomal distribution


Cervical Spine Central Disc HerniationCervical MRI Posterolateral Disc


2.  Spondylosis / Disc degeneration

- loss of height / annular bulging

- foraminal compression


3.  Bony 


A.  Uncovertebral osteophytes / hard discs

- compress nerve root anteriorly


B.  Superior articular facet osteophyte

- extend from ventral surface to compress the neural foramen

- are less common




Pain / parasthesia

- often don’t follow dermatomal distribution



- 60-70% motor deficiency


Spurling maneuver

- hyperextension with tilt toward affected side 

- stimulates radiculopathy symptoms


Nerve root signs (C6 and C7 most common)


C2 Posterior occipital headaches

C3 Occipital headache

C4 Neck and trapezial pain +/- shoulder / scapula pain

C5 Pain lateral upper arm (epaulet) / deltoid weakness / biceps jerk decreased

C6 Radial forearm and hand pain / weak biceps and wrist extension / BR reflex decreased

C7 MF pain / weak triceps / absent triceps jerk

C8 Pain ring and little fingers / weak finger flexors

T1 Ulna forearm pain / weak hand intrinsics


DDx Myopathy


Entrapment syndromes (ulna / median nerves)

Thoracic outlet syndrome

RC disease




Demonstrate loss of disc height and degeneration





- 19% of asymptomatic patients will have evidence of nerve root compression

- difficult to distinguish between hard and soft discs




Adds complementary information to MRI in C spine


Demonstrates the posterolateral impingement is from “hard” disc

- i.e. uncovertebral spur 


Cervical nerve root injections


Confirm diagnosis

- should get some temporary symptomatic relief





- concern re peripheral nerve entrapment



- are usually normal because lesion proximal to DRG



- amplitude decreased proportional to muscle atrophy


Nerve conduction velocity

- not abnormal unless severe demyelination of axons



- best for differentiating peripheral nerve root compression from central

- fibrillations




Non operative





Pharmaceutical / NSAIDS


- hot / cold

- electrical stimulation

- ROM / stretching

- isometric strengthening exercises 

Cervical traction


HCLA / nerve root injections




Lellad et al Ann Phys Rehabil Med 2009

- RCT demonstrating benefit of reducing symptoms with cervical traction


Cervical Traction


Kuijper et al BMJ 2009

- RCT demonstrating benefit of wearing semi-hard collar for 3 weeks 





- severe pain

- severe neurological impairment

- failure non operative treatment





Disc replacement










Anterior Cervical Discectomy and Fusion



- anterior approach

- interbody fusion

- iliac crest bone graft / synthetic bone graft / allograft / cage

- anterior plate / eliminates need for brace



- deal with HNP and uncovertebral osteophytes

- opens up the neuroforamina and decompresses the nerve

- fusion relieves pain of spondylosis

- anterior approach dissects little muscle and has little pain

- scar very cosmetically acceptable




Smith & Robinson / anterior approach

- divide platysma and deep cervical fascia

- SCM laterally

- divide pretracheal fascia / carotid sheath laterally

- divide prevertebral fascia in midline, separate longus colli



- decorticate end plates

- excision of osteophytes controversial

- generally only if causing compression

- otherwise will absorb with stability



- pseudarthrosis

- graft / cage displacement posteriorly

- wrong level

- insufficient decompression

- neurological injury (quadriplegia /  nerve root / RLN / Superior Laryngeal Nerve)

- injury to other structures (carotid artery / oesophagus)

- degeneration at second level


Cervical Disc Degeneration Above Fusion




2. Disc replacement



- as above

- insert disc replacement

- no anterior plate



- maintain some motion

- preserve other disc segments




Murrey et al Spine 2009

- RCT of ACDF v disc replacement

- disc replacement maintained 4o of motion

- significant reduced reoperation rate in disc replacement (1 v 8%)


3. Corpectomy



- multilevel hard and soft compression

- can remove body with disc above and below

- decompress 2 levels


Cervical HNP 2 Levels


Cervical Corpectomy APCervical Corpectomy


4. Laminoforaminotomy



- posterior approach

- deroofing of foramina




Herkowitz et al Spine 1990

- compared ACDF with posterior laminotomy / foraminotomy

- patients with both central and posterolateral discs

- combination of radiculopathy and myelopathy symptoms

- 4 year followup

- 95% vs 75% G/E


Johnson et al Spine 2000

- prospective study of patients with posterolateral disc and radiculopathy

- patients had no neck pain

- removal of HNP + uncovertebral osteophytes

- 91% improved or resolved

- 9% revision (ACDF / repeat posterior foraminotomy)





Cervical Spondylosis



Cervical spondylosis

- chronic disc degeneration & associated facet arthropathy


Cervical myelopathy

- spinal cord dysfunction

- secondary to extrinsic compression of cord or its vascular supply


Cervical radiculopathy

- sclerotomal distribution of motor &/or sensory symptoms or signs

- due to compression of nerve root




Usually begins at age 40-50




Most common at C5/6 > C6/7 > C4/5






Degenerative changes at disc / facet joints / uncovertebral joints


Clinical Features


Neck pain / headaches / local tenderness


Reduced ROM




Typical changes of spondylosis

- disc space narrowing

- osteophyte formation

- degenerative facet & uncovertebral joints


May be present in asymptomatic individuals


Cervical Spine Degeneration


CT scan


Degenerative changes


Cervical Spondylosis CT




Degenerative disc changes

- dessicated (loss of fluid), narrowed, end plate changes


Space available for cord


Neural compression

- intrinsic cord changes

- cord compression / ratio / cross sectional area


Cervical Spine Degeneration MRI






Education & Reassurance

- analgesics

- local modalities

- exercise programme

- traction







- failure non operative treatment

- disease isolated to 1 or 2 levels




Posterior Instrumented Fusion


Cervical Pedicle Screws LateralCervical Pedicle Screws AP







- restores disc height and aligment

- decompresses foramina



- autograft

- allograft

- cage


Jacobs et al Cochrane Database Review 2011

- autograft superior to discectomy alone

- autograft superior to cage in fusion rate but with higher complications


Disc Replacement



- elevate / decompress foramin

- maintain motion / decrease degeneration at subsequent levels


Burkus et al J Neurosurg Spine 2010

- prospective multicentred RCT 541 patients with single level disc degeneration

- disc replacement v ACDF

- improved outcome scores and neurological outcome in disc replacement

- no difference in rates of subsequent level surgery


PLOS One March 2015

- meta-analysis of 19 RCT of ACDF v disc replacement

- disc replacement had better scores, better pt outcome, better ROM, and decreased secondary degeneration



Technique ACDF

Anterior Cervical Discectomy and Fusion






Place the patient in the supine position

- small roll placed under the shoulder blades to drop the shoulders from the field

- exposes the anterior neck

- strap the shoulders at the side with minimal traction 

- allows visualization of the lower cervical spine on lateral radiographs

- apply skull traction with Gardner-Wells tongs

- keep head rotation to a minimum because deep dissection will depend on identifying the vertebrae midline

- prevents inadvertent injury to adjacent structures

- reverse Trendelenburg position facilitates venous drainage and results in less bleeding during surgery




Anatomic landmarks for incision 

- hyoid bone overlying C3

- thyroid cartilage overlying the C4/5 interspace

- cricoid cartilage overlying the C6 level


Use transverse incision for exposure in most cases

- more cosmetic

- from the midline to the anterior border of SCM in Langer's lines

- divide the deep cervical fascia and platysma muscle exposing the middle layer of the cervical fascia

- bluntly dissect the pretracheal fascia and palpate the carotid pulse


When three or more levels are approached, use a longitudinal incision


Dissection through the pretracheal fascia places several structures at risk

- superior and inferior thyroid arteries extend through the pretracheal fascia from the carotid artery to the midline

- travel at the C3/4 and C6/7 levels, respectively

- intervening area provides a relatively avascular plane for dissection


Recurrent laryngeal nerves

- right recurrent laryngeal nerve ascends in the neck after passing around the subclavian vessels

- courses medially and cranially at the C6–C7 level, often along with the inferior thyroid artery

- left recurrent laryngeal nerve ascends after curving around the aortic arch along the tracheoesophageal groove

- more midline and protected position

- left-sided procedure may be safer, especially when lower cervical segments are approached

- the thoracic duct is often visible on the left at the C7–T1 level and must be protected


Retract the sternocleidomastoid muscle and the carotid sheath medially

- contents (common carotid artery, internal jugular vein, and vagus nerve)


Retract the midline structures, including the trachea, esophagus, and thyroid gland medially

- complete blunt dissection through the deeper levels to the prevertebral fascia and vertebral bodies


Once the midline is identified, incise the prevertebral fascia

- elevate the medial edges of the longus colli muscles

- place blunt self-retaining retractors under the leading edges of the muscle

- Tramline retractor is used (Medial Lateral)

- take care to avoid dissecting along the longus colli muscle because of injury to the cervical sympathetic plexus

- screws in vertebral bodies for vertebral distraction





- vertebral bodies by their concave appearance 

- the discs by their more convex contour


Localize the disc space with a radiopaque marker and lateral radiograph


Remove disc

- incise the disc with an annulotomy blade

- cut lateral to medial away from the vertebral artery

- remove the disc contents and endplate cartilage to the PLL

- use thorough evaluative preoperative imaging to determine the presence of a sequestered disc behind the PLL

- palpate the PLL for the presence of a rent that may also indicate a sequestered fragment

- in the event that a rent is noted, or if an expected disc fragment is not identified, remove the PLL with Kerrison rongeurs

- beware of routine removal of the PLL, because reports of postoperative epidural hematoma have been associated with this technique


Removal of endplate and uncovertebral osteophytes is controversial

- disc space distraction reduces ligamentum flavum buckling and increases neuroforaminal area

- it is believed that fusion will arrest spur progression, and stability may allow for resorption over time

- however, this is not a consistent phenomenon

- the location and size of the offending spur must be carefully considered when performing decompression

- exposure of the uncinate processes is critical to safely remove osteophytes

- utilize a high-speed burr to excise the spur from medial to lateral



- judge the adequacy of foraminotomy

- ability to place the tip of a curret anterior to the exiting nerve root without significant resistance