treatment of cervical stenosis: update and controversies · and fusion (acdf) • high success rate...

1/28/2020

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Treatment of Cervical Stenosis: Update and Controversies

Nitin N. Bhatia, M.D.Chief, Spine Service

Professor & ChairmanDept of Orthopedic Surgery

University of California, Irvine

Disclosures

• I have a potential conflict with this presentation due to:

– Consulting/Royalty/Speaker’s Bureau payments for unrelated products from: Alphatec, Biomet, DiFusion, Orthofix, Seaspine, Spineart, Stryker

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Cervical Spondylosis

• Cervical spondylosis is a general term encompassing a number of degenerative conditions– Degenerative disc disease (DDD)

– Spinal stenosis

– Facet joint degeneration

– The formation of osteophytes (bone spurs)

– Herniated, bulging, or protruding discs

• Frequently see several of these together

• Overall, the most frequent reason for cervical spinal surgery

Degenerative Disc Disease

• Begins in the annulus fibrosis with changes to the structure and chemistry of the concentric layers

• Loss of water content and proteoglycans, which changes the disc’s mechanical properties

Degenerative Normal

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Degenerative Disease: Facet Joints

• Changes in the disc can lead to changes in the articular facets, especially hypertrophy(overgrowth) with narrowing of the adjacent neural foramen

Degenerative Disease: Osteophytes

• There also may be hypertrophy of the vertebral bodies adjacent to the degenerating disc; these bony overgrowths are known as osteophytes (or bone spurs)

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Herniated Nucleus Pulposus

• The progressive degeneration of a disc, or traumatic event, can lead to a failure of the annulus to adequately contain the nucleus pulposus

• This is known as herniated nucleus pulposus (HNP) or a herniated disc

Herniated Nucleus Pulposus

• Diagnosis via history, exam, and imaging

– 30 – 40 y/o patients

– MRI scan

– Sudden onset

• Progressive neurologic deficit may require urgent surgical decompression

• Many are asymptomatic

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Spinal Stenosis (Canal Narrowing)

• Grouped as “spinal stenosis”– Central stenosis

• Narrowing of the central part of the spinal canal

– Foraminal stenosis

• Narrowing of the foramen resulting in pressure on the exiting nerve root

T2- and T1-weighted sagittals at midspine showing spinal canal stenosis from C4/C5/C6 level

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StenoticNormal

Cervical Spinal Stenosis: Symptoms

• Neck and arm discomfort, numbness, weakness, heaviness, fatigue– Frequently not true “pain”

• Difficulty using hands

• Decreased balance

• “Myelopathy”

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Cervical Spondylotic Myelopathy

• Most common type of spinal cord dysfunction in patients older than 55 years

• Onset is usually insidious, with long periods of fixed disability and episodic worsening

• The first signs are commonly gait problems, upper-extremity numbness, or loss of fine motor control in the hands

Cervical Spondylotic Myelopathy• Unlike most degenerative

conditions of the spine, conservative treatment is not indicated

• Performing surgery relatively early (within 1 year of symptom onset) is associated with a substantial improvement in neurologic prognosis

• Delay in surgical treatment can result in permanent impairment

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Cervical Spondylotic Myelopathy

• Surgical care

– Anterior or posterior surgery

– Dependent upon the anatomy and the lordosis of the affected segments, and surgeon preference

• Posterior cervical fusion

• Laminoplasty

• Anterior cervical decompression and fusion

Cervical Spondylosis Without Myelopathy

• Surgical care

– For radicular/neurologic symptoms

– Not for axial neck pain

– Dependent on the anatomy and the lordosis of the affected segments, and surgeon preference

• Anterior cervical discectomy and fusion

• Anterior cervical corpectomy (multiple levels)

• In some cases, adjunct posterior-instrumented fusion

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Cervical Stenosis: Surgical Option

Anterior Dec / Fusion

Laminectomy

Laminectomy / Fusion

Laminoplasty

Anterior Cervical Discectomy and Fusion (ACDF)

• High success rate > 90%

– Disc removal/decompression

– Use of microscope

– Bone graft or other material for fusion

– Why consider another option?

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Are There Consequences to Spinal Fusion?

• Adjacent Segment Disease

• Pseudarthrosis

• Instrumentation Failure

• Loss of motion

Consequences of Spinal Fusion

• Adjacent segment degeneration

– Radiographic changes

– Level(s) adjacent(?) to fusion

– Often asymptomatic

– Not adjacent segment disease

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Consequences of Spine Fusion

• Adjacent level ossification disease

– Radiographic changes

– Related to plate impingement

– Also not = Adjacent Segment Disease

– Park et al. JBJS 2005

Consequences of Spine Fusion

• Adjacent segment disease

– Development of new symptoms

– Corresponding radiographic changes

– Adjacent to prior fusion

– Symptoms

– Require surgical treatment

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“The Controversy”

Natural History

of the Underlying

Disease (Spondylosis)

Consequence

of the

Surgery (Fusion)

Incidence / Etiology of ASD

• 8.5 yr F/U of 106 pts 25% stenosis (Baba et

al.)

• 5 yr F/U of 121 pts (Gore and Sepic)

– 25% new spondylosis

– 25% pre-existing spondylosis

Radiographic Studies - DegenerationRadiographic Studies - Degeneration

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• 4.5 yr F/U of 44 pts (Herkowitz et al.)

• ACDF vs. posterior foraminotomy

– ACDF 41% adjacent segment degeneration

– foraminotomy 50% adjacent level degeneration

Comparative Radiographic StudiesComparative Radiographic Studies


• 5 to 17 year follow-up (X rays) (Villas et al.)

– operated (50 patients)

– unoperated (100 patients)

• Comparison operated vs unoperated

– Operated = 32% new, 51% progression (5-17 yrs)

– Nonoperated = 36% (> 5 yrs) to 83% (> 15 yrs)

Radiographic Studies – CSRS 2005Radiographic Studies – CSRS 2005

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Study # Pts F/U(yrs)Prevalence

*Incidence*

Bohlman 122 6 9% 1.5%

Gore and Sepic

133 5 14% 3%

Williams 60 4.5 17% 4.5%

Clinical Follow-Up Studies (ACDF)Clinical Follow-Up Studies (ACDF)

*Approximately 3% per year*Approximately 3% per year


• Prevalence with longer F/U

– similar to natural history

– disc arthroplasty needs long-term F/U

– ACDF also needs better long-term F/U

Clinical Follow-Up StudiesClinical Follow-Up Studies

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• < 3 yr F/U of 334 pts (ACD F) (Lunsford et al.)

– 22 pts with adjacent segment disease

– prevalence = 6.7%

– annual incidence ~ 3%

• No difference: ACD vs ACDF

Non-Fusion: Clinical Follow-UpNon-Fusion: Clinical Follow-Up


• 2.8 yr F/U of 846 pts (Henderson et al.)

• Posterior foraminotomy

• No fusions

– 79 pts adjacent segment disease

– prevalence = 9%

– annual incidence ~ 3%


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• Similar results to ACDF

• Annual incidence ~ 3%

• New disease at adjacent segments

• Is it the fusion surgery?

• Is it the natural history of cervical spondylosis?



• 374 patients undergoing ACF

• 409 procedures (radic or myelopathy)

• 2 – 21 yr F/U

– prevalence and annual incidence

– predictions with survivorship analysis

– risk factors for adjacent segment disease

Hilibrand et al., JBJS (Am), 1999Hilibrand et al., JBJS (Am), 1999

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• Annual incidence ~ 3%

• Overall prevalence ~ 14%

• Survivorship analysis

– 13.6% @ 5 years

– 25.6% @ 10 years

Hilibrand et al., JBJS (Am), 1999Hilibrand et al., JBJS (Am), 1999

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10

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50

60

70

80

90

100

0 1 2 3 4 5 6 7 8 9 10

Year of Follow Up

% D

isea

se -

Fre

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Figure 2: Kaplan Meier Survivorship

Wang et al. Nass 2000

• UCLA Dept. of Orthopaedics Surgery Spine Service

• Enrollment 1990-1997

• 205 patients having Robinson ACDF for the treatment of degenerative disease

• 15 patients had surgery for subsequent cervical degeneration.

• All of these patients had an adjacent level fused superior or inferior to their previous fusion

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Survivorship Analysis

• Year Survivivorship Incidence of New Disease

• 1 98.9 1.1

• 2 96.1 2.8

• 3 95.4 0.7

• 4 92.6 2.8

• 5 85.6 7.0

• 6 82.1 3.5

• At 6 years, a projected estimate or 17.9% of patients needed a surgery for cervical degeneration, about 3% a year.

Adjacent Segment Disease

• 2.9% per year

– Hilibrand, Bohlman JBJS 1999

• 3.0% per year

– Wang NASS 2000

• 3.0% per year without fusion

• Evidence that it does exist

• Not increased by prior fusion

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Adjacent Segment Disease After Posterior Lumbar Fusion: Long-term Follow-up and Survivorship

AnalysisGary Ghiselli, MD

Jeffrey C Wang, MDNitin N Bhatia, MD

Wellington K Hsu, MDEdgar G Dawson, MD

UCLA Department of Orthopaedic SurgeryLos Angeles, California

Journal of Bone and Joint Surgery 2004

Results• Three fusion levels

analyzed

– Thoracolumbar

• Fused from thoracic to lumbar spine (scoliosis)

– Floating

• Not fused to sacrum or thoracic spine

– Lumbosacral

• Fused to sacrum

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Re-operation Analysis

• Overall, 37% of patients will need another procedure at an adjacent segment in 10 years

• 3.7% per year

Gary Ghiselli, MD

Jeffrey C. Wang, MD

Wellington K. Hsu, MD

Edgar G. Dawson, MD

UCLA Department of Orthopaedic Surgery

UCLA School of Medicine

Los Angeles, CA

Spine 2003

Subsequent L5-S1 Disc Degeneration After L4-L5 Isolated Lumbar Fusion: Long-term

Survivorship Analysis

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Introduction

• There is current controversy regarding future degeneration of the L5-S1 segment following adjacent segment fusion at the L4-L5 level.

• There are no long-term studies which specifically look at the L5-S1 level after L4-L5 fusion to assess the rate of degeneration at this adjacent segment.

Results

• 31 (97%) had no evidence of symptomatic degeneration at the L5-S1 level requiring additional decompression or fusion

• One patient had clinical symptoms that required a foraminotomy and laminotomy at the L5-S1 level 7.9 years after fusion (3%)

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• Lumbar Spine

• Ghiselli, Bhatia et al. JBJS 2004– 16.5% at 5 years

– 36.1% at 10 years

• Nakai et al. Eur Spine J 1996– 31% developed adjacent

segment degeneration

– Felt to be natural progression of disease

Adjacent Segment Disease after Lumbar TDA

• Zeegers et al. Eur Spine J 1999

• 2 year f/u

• 17/50 patients had additional surgery

• 11 for adjacent level disease

• Incidence 22%

• Higher than for fusion

• Variables?

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• Bertagnoli et al. Eur Spine J 2002

• 108 patients

• Adjacent segment disease progression noted in 10 patients

• Incidence 9.3%


• Stoll et al. Eur Spine J 2002

• Dynesys “mobile stabilization”

• Not disc arthroplasty

• Mean f/u of 38.1 months

• 7/83 had further surgery for adjacent segment disease

• Incidence 8.5%

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• Does disc arthroplasty decrease adjacent segment disease?

• Maybe

• Some motion preservation devices show increased adjacent segment degeneration

• Need long-term follow-up


• Huang et al.– Range of motion and adjacent level

degeneration after lumbar total disc replacement Spine J. 2006

– 8.7 year follow-up

– 70% had 1.6 degrees of motion

– 30% had 4.7 degrees• 34% of 1.6 degrees had ASD

• 0% of 4.7 degrees had ASD

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Adjacent Segment Disease• Huang et al.

– Range of motion and adjacent level degeneration after lumbar total disc replacement Spine J. 2006

– 8.7 year follow-up

– 70% had 1.6 degrees of motion

– 30% had 4.7 degrees• 34% of 1.6 degrees had ASD

• 0% of 4.7 degrees had ASD

Total number of pts with ASD/Total number pt over 9 year followup

3% per year


The Controversy Continues!

Fusion

Disease

Fusion

Disease

Patient

Disease

Patient

Disease

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Only a Direct Comparison of Patients Randomized to

Arthroplasty Versus ACDF in the Same RCT Will Give Us the

Real Answer

ACDF vs Arthroplasty

• Arthroplasty

– Randomized control trials (RCT)

– Used to justify the technique

– Proponents will cite the data

– Problems with the data

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Problem #1 with Arthroplasty RCT

• Treatment Effect– The tendency for patients to be more

enthusiastic about getting the “device”instead of the “control”

• All patients offered enrollment in RCT

• Some just want the ACDF

• Other want the device– Selection for those who want the device

– Must enroll in trial

– ½ unhappy because they get ACDF


• Treatment Effect

• May explain higher VAS scores for ACDF

• May explain lower SF-36 scores for ACDF

• Statistically significant differences

• Clinically meaningless differences

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• Confirmation Bias– The tendency of people to seek confirming

evidence of their own hypotheses

• Surgeons enthusiastic about arthroplasty

• Surgeons evaluate their own ACDF

• Surgeons who decide if surgery needed for ASD

• Surgeon bias?


• Confirmation Bias

• CSRS 2007 Prestige RCT Paper #3

• Comparison of re-operations after ACDF and Cervical Arthroplasty– 2 year reoperation rate for

cervical arthroplasty = 3.1 %

– 2 year reoperation rate for ACDF in this RCT trial = 12.1%

– 4.3% re-operation at the same level?

• Does that seem high?

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Problem #2 with Arthroplasty

RCT


• CSRS 2007 Paper #4 (Phillips)

– single level ACDF in clinical practice

– 2 yr reop rate = 3.1%

– 2 yr reop Prestige ACDF = 12.1%

• High rate of surgery for ASD after ACDF

– operate adjacent to ACDF = everyday

– how about operating adjacent to this?



• Earlier return to work after arthroplasty

• Important factor in value of arthroplasty

– Why different in ACDF patients?

– At the discretion of surgeons = 2 weeks earlier

• Completely subjective decision

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• Industry funded

• Each company wants to make their device look better

• Their job is to sell and position their product

• Statistics and graphs

• Surgeons who educate – we are the ones that are conflicted


• Anderson et al. CSRS 2005 (Medtronic Data)– RCT Bryan + Prestige (USA + Europe)

– Included 60 patients from cage study

• Incidence of re-operation– Higher with ACF

• Adjacent Segment Disease– 0.8% (CDA) vs 2.6% (ACF) (p<0.05)

– But, exclude cage pts (1.5%) (NS)

– Mean F/U 16 mos: 7/62 reop for ASD

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CSRS 2007

• Paper #2 - How about this table?????

What is the Answer?

• 15 years of data looking at ASD, Outcomes, Complications

• 943 papers in PubMed evaluating “Cervical Disc Arthroplasty”

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• Some papers show decreased ASD after cTDA vs ACDF

– Others show no difference

• Meta-analysis of high quality prospective studies shows no difference in ASD

• ASD highly influenced by non-implant factors

– Ages, Lordosis, Plate length

Verma, et al 2013

Revision Surgery

• Studies inconsistent about revision rates of cTDA vs ACDF

• cTDA revision may take longer, be more expensive, and have higher superficial infection rate

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Heterotopic Ossification

• Rates up to 13% in IDE studies of Grade 4 HO– Bridging bone across the

disc space with functional fusion

– Some studies suggest these patients do better an other cTDA patients

– Cause is unknown• Pre-op uncovertebral

hypertrophy may be related

Functional Outcomes

• Many studies designed for product approval

– Non-inferiority

– Most likely ACDF and cTDA have similar clinical outcomes

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Conclusions

• Cervical arthroplastyprovides another possible solution

• As with all surgery, patient selection is key

• Long term outcomes and complications are unknown

Thank You!

Let’s Shoot for the Stars

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treatment of cervical stenosis: update and controversies · and fusion (acdf) • high success rate...

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