When to operate on Adult Scoliosis patients and when to say ‘No’ Frank Schwab, MD Jean-Pierre...

When to operate on Adult Scoliosis patients

and when to say ‘No’

Frank Schwab, MDJean-Pierre Farcy, MDNew York University School of Medicine

NYU-Hospital for Joint DiseasesDepartment of Orthopaedic SurgeryNYU-Hospital for Joint DiseasesDepartment of Orthopaedic Surgery

What is Adult Scoliosis?

• Coronal plane deformity

• Sagittal plane deformity

• Imbalance/malalignment– Focal

– Regional

– Global

What is Adult Scoliosis?

Adolescent deformity in an adultAISA

De-novo deformity…of agingDDS

Scoliosis

Prevalence– AIS 2-4% of screened pediatric population

– Adult >60% of screened elderly population#

Demographics :Life expectancy, birth rates….Significant growth of aging population segment

# Schwab et al. SPINE 2005 May 1;30(9):1082-5

Adolescent Idiopathic Scoliosis:surgical treatment

Classification• Lenke• King

Curve pattern• apex• distribution• sagittal• overhang

Skeletal maturity• Risser sign

Surgical strategy

Curve severity• Cobb angle• progression

Adult Scoliosis Scoliosis:treatment approach

Skeletal maturity• Risser sign

PTPain MgmtBracingSurgery

Curve severity• Cobb angle• progression

Cosmesis

Pain

Disability

Classification?

Spineskeletalmaturity

30’sdisc degen.MRI changes

50’sfacet DJDdisc collapse

Unfavorable degeneration

Stable spineankylosis

stenosis spondylo deformity

The aging spine

Adult Scoliosis

Stable ankylosis

Progressive collapse

Adult Scoliosis / Deformity

What are the disability / pain generators ?

325 patients (Schwab, Farcy. SDSG. SRS 2004)

• thoracolumbar/lumbar scoliosis• SRS instrument, ODI• radiographic-clinical correlation

98 patients (Schwab,Farcy. SPINE 2004)• adult scoliosis, all levels• SF-36 • radiographic-clinical analysis

Adult Scoliosis : Clinical impact

• Significant – Spondylolisthesis

– Lateral Subluxation

– Lumbar lordosis

– Thoracolumbar alignment

– Apical level

– Sagittal Balance (SVA)

• Not significant

– Coronal Cobb

– Age

– Adolescent vs. de-novo degenerative scoliosis

Statistically significant: SRS-22, ODI, SF-12/36

Adult Scoliosis: the disability / pain generators

plain radiographs

• Apical level of deformity (lumbar dominant)

• Lumbar lordosis T12-S1

• Maximal intervertebral subluxation (frontal/sagittal)

• Sagittal balance (PlC7-S1 offset)

Selected for high clinical impact: SRS, ODI, SF-36

(excluding fractures or other pathologies…)

Classification of Adult Deformity

Type I thoracic-only curve (no other curves)II upper thoracic major, apex T4-8 III lower thoracic major, apex T9-T10IV thoracolumbar major curve, apex T11-L1V lumbar major curve, apex L2-L4Type K no scoli (<100), principal sagittal plane deformity

Lumbar Lordosis A marked lordosis >400

Modifier B moderate lordosis 0-400

C no lordosis present Cobb >00

Subluxation 0 no intervertebral subluxation any levelModifier + maximal measured subluxation 1-6mm

++ maximal subluxation >7mm

Sagittal Balance N normal, <4cm positive SVA Modifier P positive, 4-9.5cm

VP very positive, >9.5cm

Schwab et al. SPINE 2006

Adult Scoliosis

Oswestry SRS Function SRS Pain Mean SD Mean SD Mean SD

p = 0.002 p < 0.001 p = 0.007Lordosis modifier A (< -40) 27 19 69 17 65 20

Lordosis modifier C ( >= 0) 37 16 57 15 56 17

Oswestry SRS Function SRS Pain Mean SD Mean SD Mean SD

p < 0.001 p < 0.001 p < 0.001Subluxation Modifier 0 27 20 68 18 64 20

Subluxation Modifier ++ 34 18 63 16 58 19

947 patients: (86% female, 14% male)Average age 48 years (SD 18)Coronal Cobb mean 460 (SD 19)

Lordosis

Subluxation

Global Balance

ODI SRS

Thus….deformity = disability ?

Yes, certain aspects …

… Not coronal Cobb angle

Sagittal plane

Coronal/Sagittal


Focal: subluxationRegional: loss of lordosisGlobal: sagittal imbalance

Young adult: AISA

>500 thoracic

>300 lumbar (progressive)

Progression with disability

Curve progression likely– Disability later (potential)– More difficult to treat later

• Depending upon age

– Surgical risks greater later

Cosmetic concerns

Adult Scoliosis / Deformity: Why surgery ?

Weinstein S,. Spine 24(24), 1999

Pain unacceptable

Disability unacceptable

Risk/Benefit ratio

- favorable

Older Adult:

AISA = DDS

Pain/disability

failed conservative care

Adult Scoliosis / Deformity: Why surgery ?


If the justification for surgery is acceptable….

…..when is it really reasonable to operate

Don’t do it Sure success

?

Not a candidate for surgery:

– young AISA…no disability, mild/mod curve, happy

– patient who does not want surgery

– patient is unlikely to survive surgery

– patient does not understand risk/benefit • unrealistic expectations

– planned operation is not reasonable• experience, team, environment


Possibly Excellent candidate for surgery:

– young AISA…progressive, severe curve (>700)

DDS or AISA older adult:Perfectly isolated pain generator, failed extensive non-operative care

• Well informed, wishes to pursue operative care• Excellent health• Realistic expectations, highly motivated

– team has abundant experience only excellent results with planned intervention


The common cases:

• Patient might consider surgery with certain assurances• Health is acceptable (not ideal), • Pain generators present (there are several), • Non-operative care tried (variable participation and response), • Expectations are overall rather realistic.• The surgeon comfortable with intervention


?

How can we select the best patients for surgery ?(and how to optimize the chances of a successful outcome)

• non-operative care vs. surgery• If surgery…which strategy/approach

– Specific treatment algorithms lacking – few studies to guide us….where is the data ?

When to operate on Adult Scoliosis patients and when to say No

Adult Scoliosis: Thoracolumbar / Lumbar Deformity

Who gets surgery…and what type ? (n=809)

Operative rates– Lordosis

• Lost lordosis vs. good lordosis (B vs. A) 51% vs 37%, p<0.05

– Subluxation modifier• Marked subluxation vs. none (++ vs. 0) 52% vs. 36 %, p<0.05

– Sagittal Balance• Well balanced versus marked imbalance (N vs. VP) 39% vs.59%, p<0.05

Who gets surgery…and what type ?

Use of osteotomiesLordosis >400 lordo vs. no lordo : 25% vs. 50% p=0.01Sagittal balance no imbalance vs. >9.5cm : 25% vs. 53% p=0.01

Surgical ApproachAnterior only: Anterior only: no lost lordosis, no subluxationno lost lordosis, no subluxationCircumferential: some lost lordosis, marked subluxationPosterior only: marked loss of lordosis, marked sagittal imbalance

Fusion to sacrumLordosis Loss of lordosis more likely fusion to sacrum (p = .041)Sagittal Balance increasing positive balance: more fixation to sacrum.

(<4cm: 59%, 4-9.5cm: 80%, >9.5cm: 88%) (all p<0.05)


How about surgical outcomes ?

• 111patients 1-year follow up• 45 patients 2-year follow up• Adult Thoracolumbar / Lumbar major curves• Surgical treatment, complete data

– Full-length standing x-rays (0,12,24 months)

– SRS, ODI, SF-12


Mean SRS Total Score at Baseline and Two Years by Lordosis Modifier

0

10

20

30

40

50

60

70

80

Baseline Two Year

Measurement Period

Mea

n S

core

Marked Lordosis

Moderate Lordosis

No Lordosis

2-year Surgical outcome: Lordosis modifier

Lordosis modifier ‘C’…most improved

Lumbar Lordosis A marked lordosis >400

Modifier B moderate lordosis 0-400

C no lordosis present Cobb >00

Mean Oswestry Disability Index at Baseline and Two Years by Sagittal Balance Modifier and Surgical Approach

0

10

20

30

40

50

60

Baseline Two Year

Measurement Period

Mea

n S

core

<40 Anterior

<40 Circum

<40 Posterior

40 to 95 Circum

40 to 95 Circum

96+ Circum

96+ Circum

2-year Surgical outcome: sagittal balance (surgical approach)Sagittal Balance N normal, <4cm positive SVA Modifier P positive, 4-9.5cm

VP very positive, >9.5cm

with anterior approach did worst (VP posterior-only also not so good)P, VP did best with circumferential fusion

N

posterior

Mean SRS Total Score at Baseline and Two Years by Sagittal Balance Modifier and Fixation to the Sacrum

0

10

20

30

40

50

60

70

80

90

Baseline Two Year

Measurement Period

Mea

n S

core

<40 Without

<40 With

40 to 95 Without

40 to 95 With

96+ Without

96+ With

2-year Surgical outcome: sagittal balance (fixation to sacrum)

VP without fixation to sacrum got worseP and VP did best with fixation to sacrum (no difference for N)

Mean SF-12v2 PCS at Baseline and Two Years by Osteotomy

0

5

10

15

20

25

30

35

40

45

50

Baseline Two Year

Measurement Period

Mea

n S

core

No Osteotomy

Osteotomy

2-year Surgical outcome: osteotomy or not ?

Patients who had osteotomy did better !

Baseline to Two-Year Changes: Significant Interaction

ODI / SRS Total Score by lordosis • patients with no lordosis (C) greatest improvement,

• Patients with marked lordosis (A) little or no improvement

ODI / SRS Total Score by sagittal balance by surgical approach• well balanced least disabled, fused short of sacrum did best• very imbalance (VP) most disabled and worse off if not fused to sacrum

SF-12v2 / SRS Total Score by Subluxation

• significant subluxation (++,+) more improvement than no subluxation

SF-12v2 PCS / SRS Total score by Osteotomy Status

• patients with osteotomy had lower baseline scores •At 2 years f/u, patients with an osteotomy had higher scores

Follow-up data

• When is improvement clinically significant ?

– Set a bar of 10-point increase in SRS score• From 100pt. Scale

– Assumption of patient perceived improvement• Minimal Clinically Important Difference

– Berven et al.


Met Ten-Point SRS Improvement Criterion by Year and Gender

62%

100%

69%

100%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Female Male

Gender

Pe

rce

nt

Me

eti

ng

Cri

teri

on

One Year

Two Year

Minimum 10 point SRS instrument improvement

Met Ten-Point SRS Improvement Criterion by Year and Lordosis Modifier

57%

67%

100%

61%

78%

100%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

A - marked lordosis B - moderate lordosis C - No lordosis present

Lordosis Modifier

Pe

rce

nt

Me

eti

ng

Cri

teri

on

One Year

Two Year


Loss of lumbar lordosis…greater likelihood of clinical success

Met Ten-Point SRS Improvement Criterion by Year and Sagittal Balance Modifier

60%

73%

63%64%

73%

88%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Under 40 40 to 95 96 and Greater

Sagittal Balance Modifier

Pe

rce

nt

Me

eti

ng

Cri

teri

on

One Year

Two Year


At 2-yr follow up:greater imbalance patients more likely to have successful outcome

Met Ten-Point SRS Improvement Criterion by Year and Osteotomy

59%

73%

66%

80%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

No Osteotomy Performed Osteotomy Performed

Osteotomy

Pe

rce

nt

Me

eti

ng

Cri

teri

on

One Year

Two Year


Patients having osteotomies more likely to have successful outcome

Met Ten-Point SRS Improvement Criterion by Year and Baseline SF-12 PCS

83%

67%

58%

44%

92%

78%

58%

44%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Under 25 25 to Under 35 35 to Under 45 45 and Higher

Baseline SF-12 PCS

Pe

rce

nt

Me

eti

ng

Cri

teri

on

One Year

Two Year


Patients with lower baseline scores more likely to achieve significant improvement

Can we predict who will have successful surgery ?



Predictive Models

– Gender

– Age

– Apical Modifier

– Lordosis Modifier

– Subluxation Modifier

– Sagittal Balance

– Surgical Approach– Osteotomy– Fixation to Sacrum– SF-12v2 Physical Component Summary

– SF-12v2 Mental Component Summary

– SRS Total Score – Oswestry Disability Index

Outcome ?

Strength of Predictive Models

Outcome Score

(meeting the

MCID threshold)

% Correct Classification by

Model

Area Under ROC Curve (.80 and above

is considered good discrimination)

% of Surgical Cases Failing to Meet

Criterion

SRS Pain 81.1% .864 39.5%

SRS Appearance 75.4% .838 33.3%

SRS

Pain and Appearance

78.1% .845 53.5%

SF-12v2 PCS 77.9% .862 47.6%

Models to predict Clinical Improvement with Surgery

Follow-up data: Conclusions

The winners– Greater disability at start (SRS, ODI, SF-12)– Male– Subluxation >6mm– Lost lumbar lordosis <400

– Osteotomy

Who benefits least• minimal baseline disability (SRS, ODI, SF-12)

• No subluxation, no marked sagittal imbalance • Good lordosis, >400

• Lack of osteotomy



SRS, ODI, SF-12

Regional deformity

Focal deformity

Surgical approachosteotomy

Global sagittal balance

apex

gender

+

SRSODISF-12/36

Refine Classification

Predictive outcomes model

Treatment Algorithm

Adult Scoliosis / Deformity: next steps

Thank you….

When to operate on Adult Scoliosis patients and when to say ‘No’ Frank Schwab, MD Jean-Pierre...

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