Surgical treatment analysis of 809
thoracolumbar and lumbar major adult
deformity cases by a new adult
scoliosis classification system
F Schwab, JP Farcy, K Bridwell, S Berven, S Glassman,
W Horton, M Shainline
Spinal Deformity Study Group
Zorab Symposium 2006
Background
Unlike pediatric and adolescent scoliosis, no accepted
classification system exists for adult scoliosis

Scoliosis in the adult population
– prevalence as high as 60%
– significant pain and disability
– Quality of life issues

Classification systems provide
– Common language for communication
– Correlation with clinical impact
 treatment algorithms
 surgical guidelines
Background
Adult deformity: Treatment approach
Curve severity
• Cobb angle
• progression
Skeletal maturity
• Risser sign
Cosmesis
Pain
Disability
PT
Pain Mgmt
Bracing
Surgery
Background
Multi-center prospective study
Clinical Group
Scoliosis with apex T4 to L4
Degenerative or idiopathic
809 consecutive patients
Radiographic analysis
full length, standing films
Cobb angle,
apical level of deformity,
sagittal plane lumbar alignment
Health assessment
questionnaires
ODI / SRS-29 / SF-12
Classification System
Apical level
Lumbar lordosis modifier
Intervertebral subluxation modifier
Global Balance modifier
Background
Adult Scoliosis Classification
1. Type
Type I
Type II
Type III
Type IV
Type V
Thoracic
only
Upper Thoracic
major
Lower Thoracic
major
Thoraco-lumbar
major
Lumbar
major
no other
curves
Apex
T9-T10
Apex
T9-T10
Apex
T11-L1
Apex
L2-L4
2. Modifiers
Lumbar Lordosis
A : marked >400
B : moderate 0-400
C : no lordosis, Cobb >00
Global Balance
Intervertebral Subluxation
0 : none at any level
+ : max = 1-6mm
++ : max >7mm
N
Neutrally balanced <4cm
P Positively balanced 4-9.5cm
VP Very Positive
>9.5cm
Purpose
Adult Scoliosis Classification
Reliable classification with
significant correlation to
clinical symptoms
Prediction of treatment
patterns and surgical rates
???
Materials & Methods
1. Clinical group
•
•
•
•
Spinal Deformity Study Group database
Prospective, consecutive 809 patients review
Ages > 18 y.o.
Thoracolumbar or lumbar major scoliosis
•Type IV and Type V deformities only.
2. Health questionnaires
• Oswestry Disability Index (ODI)
• Scoliosis Research Society instrument (SRS-22)
• Short From 12 (SF-12)
Materials & Methods
3. Radiographic parameters
•
•
•
•
Full-length standing films
Frontal Cobb angle,
Apical level,
Sagittal lumbar alignment (T12-S1),
Sagittal Balance
N Neutrally balanced <4cm
P Positively balanced 4-9.5cm
VP Very Positive
>9.5cm
Lumbar Lordosis
A : marked >40°
B : moderate 0-40 °
C : no lordosis, Cobb >0°
Intervertebral Subluxation
0 : none at any level
+ : max = 1-6mm
++ : max >7mm
Materials & Methods
4. Treatment approach
• Surgical vs. non-surgical
• If Surgical:
• Anterior, Posterior, circumferential
• Use of osteotomies
• Extension of fusion to sacrum
5. Data Analysis
• Treatment Analysis regarding
•
HRQOL measures
• SRS-22, ODI, SF-12
• Correlation analysis
• Classification types vs. treatment given
Results
Patients Distribution
806 thoracolumbar/lumbar major
deformities
– Type IV
– Type V
n=311
n=495
– Mean age 53.1 y.o. (+/- 15.3)
– 700 Females (87%)
– 106 Males (13%)
Results

Surgical rates
Rates of operative treatment
– Lordosis modifier
 B vs. A (51% vs. 37%, p<0.05), trend for A vs. C (46%)
– Subluxation modifier
 ++ vs. 0 (52% vs. 36 %, p<0.05), trend vs. + (42 %)
– Sagittal Balance
 N vs. VP: 39% vs. 59%, p<0.05
Results
Treatment Analysis: Type IV, V curves
92% highest level of fixation above apex of major curve.
97% lowest level of fixation below apex of major curve.
10% to level of sublux, 87% at least one level beyond
Fusion to sacrum
Apical Level
Trend for type V patients more likely to have fixation to sacrum (p=.074)
Lordosis Modifier
mod B patients more likely fusion to sacrum than mod A patients (p=.041)
Sagittal Balance Modifier
increasing positive balance: more likely fixation extended to the sacrum.
(mod N: 59%, mod P: 80%, mod VP: 88%) (all p<0.05)
Results
Treatment Analysis: Type IV, V curves
Surgical Approach

Anterior only
– mostly lordosis modifier A
– Subluxation modifier 0
– Sagittal balance modifier N

Circumferential:
– trend most common modifier B
– Most commonly subluxation
modifier ++

Posterior only:
– mostly lordosis modifier C
– Sagittal balance modifier VP
Use of osteotomies

Lordosis modifier A vs. C
– 25% vs. 50% p=0.01

Sagittal balance N vs. VP
–
25% vs. 53% p=0.01
Results
Main findings
Treatment
• Good lordosis (modifier A) less likely to have surgery
• Most likely to require surgery:
• loss of lordosis (C),
• marked subluxation (++)
• sagittal plane imbalance (VP)
If surgery
• Cross level of subluxation
• Osteotomies to realign sagittal plane
• lordosis modifier C gets most likely to require osteotomy
• fusion to sacrum: with increasing sagittal imbalance, lost lordosis
Discussion - Conclusion

Adult scoliosis classification
Clinical Impact established:
– HRQOL
– Treatment….non-op vs. surgical
– Surgical strategy…we’re getting there
How about results of treatment ?
Work toward surgical guidelines
2 yr
f/u
Discussion - Conclusion
Adult scoliosis
classification
Reliable
Clinical impact
• disability
• surgical rate
Surgical strategy ?
Can we broaden to a:
Comprehensive Adult Deformity
Classification
Classification of Adult Deformity
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
Next Steps
Adult scoliosis classification
Refine Classification
• Pelvic modifier
• Co-morbidity index
• Patient expectation scale
Longitudinal follow up
• who responds well to conservative care
• who benefits (how much) from surgery
•Complications ?
Surgical analysis (2yr f/u)
• what strategies are most effective