When to operate on
Adult Scoliosis patients
and when to say ‘No’
Frank Schwab, MD
Jean-Pierre Farcy, MD
New York University School of Medicine
NYU-Hospital for Joint Diseases
Department of Orthopaedic Surgery
What is Adult Scoliosis?
What is Adult Scoliosis?
• Coronal plane deformity
• Sagittal plane deformity
• Imbalance/malalignment
– Focal
– Regional
– Global
Adolescent deformity in an adult
AISA
De-novo deformity…of aging
DDS
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
Curve severity
• Cobb angle
• progression
Classification
• Lenke
• King
Skeletal maturity
• Risser sign
Curve pattern
• apex
• distribution
• sagittal
• overhang
Surgical
strategy
Adult Scoliosis Scoliosis:
treatment approach
Curve severity
• Cobb angle
• progression
Skeletal maturity
• Risser sign
Classification
?
Cosmesis
Pain
Disability
PT
Pain Mgmt
Bracing
Surgery
The aging spine
Spine
skeletal
maturity
30’s
disc degen.
MRI changes
50’s
facet DJD
disc collapse
Stable spine
ankylosis
Unfavorable degeneration
stenosis
spondylo deformity
Adult Scoliosis
Progressive
collapse
Stable ankylosis
Adult Scoliosis / Deformity
What are the disability / pain generators ?
98 patients (Schwab,Farcy. SPINE 2004)
• adult scoliosis, all levels
• SF-36
• radiographic-clinical analysis
325 patients (Schwab, Farcy. SDSG. SRS 2004)
• thoracolumbar/lumbar scoliosis
• SRS instrument, ODI
• radiographic-clinical correlation
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
Schwab et al. SPINE 2006
Type
I
II
III
IV
V
Type K
thoracic-only curve (no other curves)
upper thoracic major, apex T4-8
lower thoracic major, apex T9-T10
thoracolumbar major curve, apex T11-L1
lumbar major curve, apex L2-L4
no scoli (<100), principal sagittal plane deformity
Lumbar Lordosis
Modifier
A
B
C
marked lordosis >400
moderate lordosis 0-400
no lordosis present Cobb >00
Subluxation
Modifier
0
+
++
no intervertebral subluxation any level
maximal measured subluxation 1-6mm
maximal subluxation >7mm
Sagittal Balance
Modifier
N
P
VP
normal, <4cm positive SVA
positive, 4-9.5cm
very positive, >9.5cm
Adult Scoliosis
947 patients: (86% female, 14% male)
Average age 48 years (SD 18)
Coronal Cobb mean 460 (SD 19)
ODI
Lordosis
Lordosis modifier A (< -40)
Lordosis modifier C ( >= 0)
Subluxation
Subluxation Modifier 0
Subluxation Modifier ++
Global
Balance
Oswestry
Mean
SD
p = 0.002
27
19
37
16
Oswestry
Mean
SD
p < 0.001
27
20
34
18
SRS
SRS Function
Mean
SD
p < 0.001
69
17
57
15
SRS Function
Mean
SD
p < 0.001
68
18
63
16
SRS Pain
Mean
SD
p = 0.007
65
20
56
17
SRS Pain
Mean
SD
p < 0.001
64
20
58
19
Adult Scoliosis / Deformity
Thus….deformity = disability ?
Yes, certain aspects …
Focal: subluxation
Regional: loss of lordosis
Global: sagittal imbalance
… Not coronal Cobb angle
Coronal/Sagittal
Sagittal plane
Adult Scoliosis / Deformity: Why surgery ?
Young adult: AISA
>500 thoracic
>300 lumbar (progressive)
Curve progression likely
– Disability later (potential)
– More difficult to treat later
• Depending upon age
– Surgical risks greater later
Progression with disability
Cosmetic concerns
Weinstein S,. Spine 24(24), 1999
Adult Scoliosis / Deformity: Why surgery ?
Older Adult:
AISA = DDS
Pain unacceptable
Disability unacceptable
Pain/disability
failed conservative care
Risk/Benefit ratio
- favorable
Adult Scoliosis / Deformity
If the justification for surgery is acceptable….
…..when is it really reasonable to operate
?
Don’t do it
Sure success
Adult Scoliosis / Deformity
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
Adult Scoliosis / Deformity
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
Adult Scoliosis / Deformity
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
?
When to operate on Adult Scoliosis patients and when to say No
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 ?
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
Adult Scoliosis: Thoracolumbar / Lumbar Deformity
Who gets surgery…and what type ?
Use of osteotomies
Lordosis >400 lordo vs. no lordo : 25% vs. 50% p=0.01
Sagittal balance no imbalance vs. >9.5cm : 25% vs. 53% p=0.01
Surgical Approach
Anterior only: no lost lordosis, no subluxation
Circumferential: some lost lordosis, marked subluxation
Posterior only: marked loss of lordosis, marked sagittal imbalance
Fusion to sacrum
Lordosis
Sagittal Balance
Loss of lordosis more likely fusion to sacrum (p = .041)
increasing positive balance: more fixation to sacrum.
(<4cm: 59%, 4-9.5cm: 80%, >9.5cm: 88%) (all p<0.05)
Adult Scoliosis: Thoracolumbar / Lumbar Deformity
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
2-year Surgical outcome: Lordosis modifier
Lumbar Lordosis
Modifier
A
B
C
marked lordosis >400
moderate lordosis 0-400
no lordosis present Cobb >00
Mean SRS Total Score at Baseline and Two Years by Lordosis
Modifier
80
70
60
Mean Score
50
Marked Lordosis
Moderate Lordosis
No Lordosis
40
30
20
10
0
Baseline
Two Year
Measurement Period
Lordosis modifier ‘C’…most improved
2-year Surgical outcome: sagittal balance (surgical approach)
Sagittal Balance
Modifier
N
P
VP
normal, <4cm positive SVA
positive, 4-9.5cm
very positive, >9.5cm
Mean Oswestry Disability Index at Baseline and Two Years by Sagittal
Balance Modifier and Surgical Approach
60
50
Mean Score
40
<40 Anterior
<40 Circum
<40 Posterior
40 to 95 Circum
40 to 95 Circum
96+ Circum
posterior
96+ Circum
30
20
10
0
Baseline
Two Year
Measurement Period
N with anterior approach did worst (VP posterior-only also not so good)
P, VP did best with circumferential fusion
2-year Surgical outcome: sagittal balance (fixation to sacrum)
Mean SRS Total Score at Baseline and Two Years by Sagittal Balance
Modifier and Fixation to the Sacrum
90
80
70
Mean Score
60
<40 Without
<40 With
40 to 95 Without
40 to 95 With
96+ Without
96+ With
50
40
30
20
10
0
Baseline
Two Year
Measurement Period
VP without fixation to sacrum got worse
P and VP did best with fixation to sacrum (no difference for N)
2-year Surgical outcome: osteotomy or not ?
Mean SF-12v2 PCS at Baseline and Two Years by Osteotomy
50
45
40
35
Mean Score
30
No Osteotomy
Osteotomy
25
20
15
10
5
0
Baseline
Two Year
Measurement Period
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
Adult Scoliosis: Thoracolumbar / Lumbar Deformity
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.
Minimum 10 point SRS instrument improvement
Met Ten-Point SRS Improvement Criterion by Year and Gender
100%
100%
100%
90%
Percent Meeting Criterion
80%
69%
70%
62%
60%
One Year
Two Year
50%
40%
30%
20%
10%
0%
Female
Male
Gender
Minimum 10 point SRS instrument improvement
Met Ten-Point SRS Improvement Criterion by Year and Lordosis
Modifier
100%
100%
100%
90%
78%
Percent Meeting Criterion
80%
70%
67%
61%
60%
57%
One Year
Two Year
50%
40%
30%
20%
10%
0%
A - marked lordosis
B - moderate lordosis
C - No lordosis present
Lordosis Modifier
Loss of lumbar lordosis…greater likelihood of clinical success
Minimum 10 point SRS instrument improvement
Met Ten-Point SRS Improvement Criterion by Year and Sagittal
Balance Modifier
100%
88%
90%
80%
Percent Meeting Criterion
73%
73%
70%
64%
63%
60%
60%
One Year
Two Year
50%
40%
30%
20%
10%
0%
Under 40
40 to 95
96 and Greater
Sagittal Balance Modifier
At 2-yr follow up:
greater imbalance patients more likely to have successful outcome
Minimum 10 point SRS instrument improvement
Met Ten-Point SRS Improvement Criterion by Year and Osteotomy
100%
90%
80%
80%
Percent Meeting Criterion
73%
70%
60%
66%
59%
One Year
Two Year
50%
40%
30%
20%
10%
0%
No Osteotomy Performed
Osteotomy Performed
Osteotomy
Patients having osteotomies more likely to have successful outcome
Minimum 10 point SRS instrument improvement
Met Ten-Point SRS Improvement Criterion by Year and Baseline SF-12
PCS
100%
92%
90%
83%
78%
Percent Meeting Criterion
80%
70%
67%
58%
60%
58%
50%
44%
44%
One Year
Two Year
40%
30%
20%
10%
0%
Under 25
25 to Under 35
35 to Under 45
45 and Higher
Baseline SF-12 PCS
Patients with lower baseline scores more likely to achieve significant improvement
When to operate on Adult Scoliosis patients and when to say No
How can we select the best patients for surgery ?
(and how to optimize the chances of a successful outcome)
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 ?
Models to predict Clinical Improvement with Surgery
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%
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
When to operate on Adult Scoliosis patients and when to say No
How can we select the best patients for surgery ?
(and how to optimize the chances of a successful outcome)
Regional deformity
apex
Global sagittal balance
SRS, ODI, SF-12
Surgical approach
osteotomy
gender
Focal deformity
Adult Scoliosis / Deformity: next steps
Refine Classification
+
SRS
ODI
SF-12/36
Predictive outcomes model
Treatment Algorithm
Thank you….