1. 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

2. What is Adult Scoliosis?

4. 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

5. 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

6. Adolescent Idiopathic Scoliosis: surgical treatment
Curve severity
Cobb angle
progression
Skeletal maturity
Risser sign
Curve pattern
apex
distribution
sagittal
overhang
Classification
Lenke
King
Surgical
strategy

7. Adult Scoliosis Scoliosis: treatment approach
Curve severity
Cobb angle
progression
Classification ?
Skeletal maturity
Risser sign
Cosmesis PT
Pain Mgmt
Bracing
Surgery
Pain
Disability

8. The aging spine Adult Scoliosis 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

9. Progressive collapse
Stable ankylosis

10. 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

11. 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

12. 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…)

13. Classification of Adult Deformity
Schwab et al. SPINE 2006
Type I thoracic-only curve (no other curves)
II upper thoracic major, apex T4-8
III lower thoracic major, apex T9-T10
IV thoracolumbar major curve, apex T11-L1
V lumbar major curve, apex L2-L4
Type 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 level
Modifier + 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

14. Adult Scoliosis ODI SRS 947 patients: (86% female, 14% male)
Average age 48 years (SD 18)
Coronal Cobb mean 460 (SD 19)
ODI
SRS
Lordosis
Subluxation
Global
Balance

15. Adult Scoliosis / Deformity
Thus….deformity = disability ?
Yes, certain aspects …
… Not coronal Cobb angle
Coronal/Sagittal
Focal: subluxation
Regional: loss of lordosis
Global: sagittal imbalance
Sagittal plane

16. Adult Scoliosis / Deformity: Why surgery ?
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
Weinstein S,. Spine 24(24), 1999

17. Adult Scoliosis / Deformity: Why surgery ?
Older Adult:
AISA = DDS
Pain/disability
failed conservative care
Pain unacceptable
Disability unacceptable
Risk/Benefit ratio
- favorable

18. Adult Scoliosis / Deformity
If the justification for surgery is acceptable….
…..when is it really reasonable to operate
Don’t do it ?
Sure success

19. 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

20. 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

21. 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 ?

22. 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 ?

23. 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

24. 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 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)

25. How about surgical outcomes ?
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

26. 2-year Surgical outcome: Lordosis modifier
Lumbar Lordosis A marked lordosis >400
Modifier B moderate lordosis 0-400
C no lordosis present Cobb >00
Lordosis modifier ‘C’…most improved

27. 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
posterior N
with anterior approach did worst (VP posterior-only also not so good)
P, VP did best with circumferential fusion

28. 2-year Surgical outcome: sagittal balance (fixation to sacrum)
VP without fixation to sacrum got worse
P and VP did best with fixation to sacrum (no difference for N)

29. 2-year Surgical outcome: osteotomy or not ?
Patients who had osteotomy did better !

30. 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

31. Follow-up data When is improvement clinically significant ?
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.

32. Minimum 10 point SRS instrument improvement

33. Minimum 10 point SRS instrument improvement
Loss of lumbar lordosis…greater likelihood of clinical success

34. Minimum 10 point SRS instrument improvement
At 2-yr follow up:
greater imbalance patients more likely to have successful outcome

35. Minimum 10 point SRS instrument improvement
Patients having osteotomies more likely to have successful outcome

36. Minimum 10 point SRS instrument improvement
Patients with lower baseline scores more likely to achieve significant improvement

37. 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 ?

38. Predictive Models Outcome ? Surgical Approach Gender Osteotomy Age
Fixation to Sacrum
SF-12v2 Physical Component Summary
SF-12v2 Mental Component Summary
SRS Total Score
Oswestry Disability Index
Gender
Age
Apical Modifier
Lordosis Modifier
Subluxation Modifier
Sagittal Balance
Outcome ?

39. Strength of Predictive Models
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%

40. 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

41. 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)
apex
Regional deformity
SRS, ODI, SF-12
Global sagittal balance
Surgical approach
osteotomy
gender
Focal deformity

42. Adult Scoliosis / Deformity: next steps
Refine Classification
Predictive outcomes model +
SRS
ODI
SF-12/36
Treatment Algorithm

43. Thank you….