Cleveland Spine Review Cervical Stenosis: Decision Making Process Gordon R. Bell, M.D. Director, Center for Spine Health

Decision Making  Asymptomatic cervical stenosis – To treat or not to treat?

 Cervical myelopathy – To treat or not to treat?  Natural history

 Surgical approach – Anterior, Posterior, Combined? Center for Spine Health

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Decision Making

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General Principle  

Better to treat symptoms than imaging First question: Is the stenosis asymptomatic or symptomatic?

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Cervical Stenosis 

Average sagittal canal diameter: – 200 asymptomatic subjects – Fixed 72 inch target distance

C1: 22mm C2: 20mm C3C3-7: 17mm Normal:  15mm Stenosis: Stenosis:  13mm Wolfe, et.al. - 1956

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C1-7: cord diameter ≈ 10 mm (range 8.5-11.5 mm) C4-7: 1/4 of the canal is unoccupied – Can accommodate spondylotic spurs without cord compression Center for Spine Health

Cervical Stenosis 

MRI: Reduced functional reserve – ↓ CSF surrounding cord

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Asymptomatic Stenosis: To Operate or Not? 

Unknown risks of cervical stenosis – Traumatic SCI  1/30,000 in general population  Small risk of SCI in relation to high prevalence of

cervical stenosis  Tends to occur in younger, nonstenotic population

– Development of myelopathy Fassett, et al – Seminars in Spine Surgery, 2007 Center for Spine Health

Risk of Developing Myelopathy 

323 asymptomatic pts. with stenosis from OPLL followed for 17.6 years – 17% developed myelopathy (1% per year) Matsunaga, et al – JNS, 2004 (suppl 3)

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66 asymptomatic pts. with stenosis followed prospectively – 5% annual risk of developing myelopathy Bednarik, et al – Spine, 2004 Center for Spine Health

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Risk of Developing Myelopathy 

Summary – Risk of developing myelopathy with cervical stenosis: ≈ 3% per year  Influence of age (young pts. have greater

cumulative risk)

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Asymptomatic Stenosis: To Operate or Not?  

Unknown Elderly patient – Limited life expectancy – Cumulative lifetime risk of neuro deficit small – Higher surgical risks

Non-op 

Younger patient – Cumulative lifetime risk of neuro deficit higher

Surgery

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3% annual risk x 20 years > 50%

– Higher risk of traumatic SCI

Fassett, et al – Seminars in Spine Surgery, 2007

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Canal Size vs. Neurological Deficit

“Large” canal is protective Eismont – Spine, 1984

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Prophylactic Surgical Decompression: Pro 

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Since many (majority) pts. with myelopathy do not regain normal function, should consider prophylactic surgery in young asymptomatic pt. Pts. with myelopathy – Older – Longer duration of disease – More comorbidities

Worse outcome

Fassett, et al – Seminars in Spine Surgery, 2007 Center for Spine Health

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Prophylactic Surgical Decompression: Pro 

Myelopathic symptoms may develop gradually and not be noticed until severe and irreversible – Hand dexterity, L.E. coordination (“old age”)

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Prophylactic Surgical Decompression: Con 

Low risks of SCI and myelopathy – Annual risk of traumatic SCI: 1/30,000 – Annual risk of myelopathy with stenosis: ≈ 3%

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No proven benefit to prophylactic surgery Risks of surgery Caveat: close follow-up / compliant pt. Fassett, et al – Seminars in Spine Surgery, 2007 Center for Spine Health

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Fate of Asymptomatic Cervical Stenosis 

72 asymptomatic pts. with canal < 9 mm – Annual exams and MRI – 48 pts. followed ≥ 2 yrs.

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None developed para/quadriplegia 8 had surgery – 3 pts. myelopathy – 3 pts. radiculopathy – 2 pts. myeloradiculopathy Riew, et al – AAOS, 2012 Center for Spine Health

Asymptomatic Cervical Stenosis 

Conclusion: most pts. can safely defer surgery Riew, et al – AAOS, 2012

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Natural History of Spondylosis Clinical 

Little data available Natural History and Prognosis of Cervical Spondylosis

Group I: Myelopathy (44 pts.) Group II: No myelopathy (51 pts.) Lees and Turner - Br. Med. J. - 1963 Center for Spine Health

CSM Natural History 

Cervical myelopathy (44 pts.) – 4 pts. – presented with mild disability  4/4 remained mildly disabled

– 15 pts – presented with moderate disability 

11/15 remained moderate or worse

– 25 pts. – presented with severe disability  24/25 – remained moderately or severely disabled

Lees and Turner - Br. Med. J. - 1963 Center for Spine Health

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CSM Natural History 

Conclusion: – Course of myelopathy usually prolonged – Long periods of nonprogressive disability (stepwise progression) – Rapid progressive deterioration rare Lees and Turner - Br. Med. J. - 1963

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CSM Natural History 

36 pts treated nonsurgically over 19 yrs. – 27 – presented with mild disability  18/27 – remained mildly disabled

– 9 – presented with mod.-severe symptoms  6/9 – continued with mod.mod.-severe symptoms

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Pts. over 60 y/o had worst prognosis Nurick – Brain, 1972

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CSM: Natural History  

Retrospective study of 121 pts. with CSM 3 groups: – 75%: episodic progression – 20%: slow, steady, relentless progression – 5%: rapid onset, lengthy periods of stability

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Conclusion: prognosis poor; spontaneous improvement rare Clarke and Robinson – Brain, 1956 Center for Spine Health

CSM: Natural History •Prolonged, non-progressive disability Lees and Turner – 1963

•Deterioration & function related to age of patient (60 y/o) and severity at presentation Nurick - 1972

• Retrospective study of 24 patients followed for 6.5 yrs • 1/3 improved • 1/3 stable Roberts – 1966 • 1/3 deteriorated Center for Spine Health

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Natural History of CSM Systematic Review 

National Library of Medicine & Cochrane Database – 32 publications identified  5 with homogeneous groups and utilizing

objective outcome measures

Matz,et al – JNS:Spine -2009 Center for Spine Health

Natural History of CSM Systematic Review (Conclusions) 1.

Pts. < 75 y/o and mild CSM (mJOA < 12)  Stable clinical course over 3 years

2.

Predictive factors  Anterior horn EMG abnormalities or presence of radiculopathy → development of CSM

3.

Natural history is variable  Slow, stepwise decline  Long quiescent periods without progression of Sx Matz,et al – JNS:Spine -2009 Center for Spine Health

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CSM: Natural History

Summary •Variable clinical course •Majority do not improve and may deteriorate •> 60 y/o •Should be referred for evaluation

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Surgery for Myelopathy  

Prospective, controlled studies lacking Unknowns / controversies: – Timing of surgery  Short prepre-operative period of SX

better

– Surgical approach  Anterior vs Posterior?

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Clinical Prognostic Indicators of Surgical Outcome   

↑Age (> 60-70 y/o) ↑Duration of symptoms ↓Preoperative neurol. fnct.

Worse outcome

Holly, et al – JNS: Spine - 2009

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Surgical Goals 

Arrest progression of myelopathy – ± improvement in function (hopefully)

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Cervical Myelopathy: Surgical Options 

Anterior Options – – –

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Discectomies and interbody graft (ACDF) Corpectomy and strut graft Hybrid (ACDF + corpectomy): corpectomy): keep intervening segment as intermediate point of fixation

Posterior Options – Laminectomy – Laminectomy + fusion – Laminaplasty

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Combined Ant.-Post. Options

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Decision Making “Indecision may or may not be my problem” Jimmy Buffett from “Don’ Don’t Chu Know” Know” ( Barometer Soup CD)

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CSM Surgical Rx  

Lack of prospective, randomized studies Comparable outcome with ant. or post. decompression – Laminectomy associated with deterioration (kyphosis) – Anterior approach for short segment disease Mummaneni, et al- JNS: Spine, 2009

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CSM: Surgical Options 

Many cases can be treated by any of several methods: – Anteriorly – Posteriorly – Combined (anterior and posterior)

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In some cases there may not be a single best way – Surgeon preference – Complications Center for Spine Health

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Normal

Stenotic Center for Spine Health

Anterior Surgery: Advantages 

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Direct neural decompression of ventral pathology Relieve neural compression from kyphosis – Correct kyphosis

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Prevents recurrent disease at fused segments

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Anterior Surgery Indications  Anterior

compression

– Disc – Anterior osteophytes – Often preferred procedure (corpectomy) for multi-level cord compresion (e.g. congenital stenosis) – Compression with kyphosis

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Anterior Surgery: Disadvantages  

Adjacent level degeneration Complications – Dysphagia, dysphonia, airway (hematoma)

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Surface Anatomy Landmarks

C3: Hyoid C4-5: Thyroid C6: Cricoid

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CSM Anterior Surgical Options

Rao, et al –JBJS, 2006

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CSM From Focal Pathology: HNP 

Gold standard: Anterior Cervical Discectomy and Fusion (ACDF)

C3-4 HNP, stenosis, myelomalacia Center for Spine Health

CSM: Ant. Surgical Options Single Level Focal Disease

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CSM: Ant. Surgical Options 2 Level Focal Disease C4-5

C5-6

58 y/o ♀ with gait disturbances

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Anterior Surgery 

Risk: Insertion of Kerrison into narrowed canal (e.g. 1mm Kerrison into 6mm canal  15-20% additional narrowing)

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CSM: Multifocal Disease Multilevel ACDF Indications 

Contraindications

Compression limited to disc space (disc or osteophyte) osteophyte)

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Congenital (diffuse) stenosis Acquired stenosis with stenosis opposite vert. body

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Multilevel ACDF Advantages 

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Can achieve segmental lordosis with wedge shaped grafts Segmental fixation at each level Can be performed if kyphotic

Disadvantages   

Takes longer than corpectomy Swallowing issues Higher pseudarthrosis rate C5C5-6 graft resorption with proximal plate migration

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CSM: Ant. Surgical Options Diffuse Disease 

Multilevel discectomies & interbody graft (ACDF)

2 level ACDF

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3 level ACDF

Corpectomy and strut graft 2 level corpectomy

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CSM: Diffuse Disease Corpectomy Advantages 

Only prox. and distal ends of graft must incorporate – Pseudarthrosis less likely than with multilevel ACDF

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Can be performed in kyphosis Can address congenital stenosis Can be combined with discectomy above or below (“ (“hybrid” hybrid” construct)

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CSM: Diffuse Disease Corpectomy Disadvantages 

Must be supplemented with post.instrumentation if > 2 levels 1st Stage: Stage: C2C2-7 corpectomy + fibular strut 2nd Stage: Stage: Post C2C2-T2 inst. fusion

PrePre-op

PostPost-op

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Corpectomy Technique

Can pack bone from corpectomy into allograft strut Center for Spine Health

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Corpectomy: Materials and Constructs

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Hybrid Construct

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Corpectomy: Modes of Failure and a Solution Hybrid Construct

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CSM: Diffuse Ant. Disease Hybrid Options 

Hybrid (ACDF + corpectomy): keep intervening segment as intermediate point of fixation

Corpectomy proximal

Corpectomy proximal and distal

Corpectomy distal Center for Spine Health

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CSM with Mild Kyphosis

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CSM: Posterior Surgical Options 

Posterior Decompression – Laminectomy – Laminectomy + fusion – Laminaplasty

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Laminectomy Indications: 

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Contra-indications:

MultiMulti-level spondylosis with cord compression and normal lordosis Post. compression with previous anterior fusion (i.e. stable anteriorly) anteriorly)

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Growing child / adolescent  “Swan neck deformity” deformity” Cervical kyphosis Focal ant. compression (e.g. large ant. HNP)

Problem: Deterioration of results over time Center for Spine Health

Kyphosis 

Approaching anterior pathology from a posterior approach usually does not address underlying problem

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Laminectomy: Disadvantages   

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↑ segmental motion ↑ segmental instability ↑ risk of late neurological deterioration (subset) ↑ risk of kyphosis

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Postlaminectomy Kyphosis 

Postlaminectomy kyphosis: 11%-47% – Causes cord to lie against impinging anterior structures  Can lead to recurrent myelopathy

– ↑ neck pain – Iatrogenic spondylolisthesis if aggressive facetectomy performed  May occur following as little as 25% facetectomy

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82 y/o ♀ with Gait Disturbance

Surgical Procedure: C1-2 Laminectomy

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Laminectomy and Fusion Indications  

Posterior compression Neutral or lordotic posture

Contraindications  

Fixed kyphosis Focal ventral pathology

– Or ability to convert from kyphotic to neutral/lordotic neutral/lordotic   

Multilevel stenosis Instability present Supplemental fixation for concomitant long ant. fusion with only terminal fixation

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CSM: Surgical Options Diffuse Disease (Post. Approach)

Good lordosis Posterior pathology Center for Spine Health

CSM: Ant-Post Surgical Options Diffuse Disease

C3-4

C4-5

C5-6

C4-6 Corpectomy C3-7 fusion

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Laminoplasty 

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Devised as solution to post-operative kyphosis after cervical laminectomy Benefit: Posterior decompression + stability

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Sagittal Alignment Lordosis

Must have pre-existing lordotic (neutral) alignment!

Kyphosis

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Laminaplasty Techniques Suture ± anchor

Bone strut

Plate

“French door”

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CSM: Algorithm Lordotic (neutral) Anterior Surgery

Single level ACDF

(Laminectomy)

Posterior Surgery Laminectomy + Fusion

Laminaplasty

Multilevel ACDF

Corpectomy ≤ 2 levels: Corpectomy only >2 levels: Corpectomy + Post. Fusion or Hybrid

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CSM: Algorithm Kyphotic (Anterior Surgery)

Single level

Multilevel

Corpectomy

Single level ACDF

≤ 2 levels

Corpectomy alone ± Plate

Multilevel ACDF

> 2 levels

Hybrid

Supplemental Post. Instrumentation Center for Spine Health

Conclusions: Cervical Myelopathy  

Variable clinical course Majority do not improve and may deteriorate – > 60 y/o

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Should be referred for evaluation

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CSM Non-operative Rx 

Most appropriate for mild, subtle myelopathy – Careful, regular monitoring is mandatory!

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Not appropriate for older pts. with motor deficits

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CSM Non-operative Rx 

Avoid “risky” behaviors – Cervical manipulation – Certain activities (any activity with risk of falling on head)

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Avoid epidurals in stenotic canal Must follow closely! Progressive deterioration → surgery Center for Spine Health

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CSM Surgical Rx  

Lack of prospective, randomized studies Comparable outcome with ant. or post. decompression – Laminectomy associated with deterioration (kyphosis) – Anterior approach for short segment disease Mummaneni, et al- JNS: Spine, 2009

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CSM Surgical Rx  

ACDF Corpectomy – ± Plates

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Laminectomy – ± Fusion

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Laminaplasty

Similar rate of neurological recovery Yonenobu-Spine, 1985

Difference in outcome depends on complications and other factors Center for Spine Health

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The End

u k yo n a Th tion! atten

o fo r y

ur

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