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7/31/2013

Overview of ISSG and Health
Impact of Adult Spinal Deformity
Shay Bess, MD
News from the Frontlines of Adult Spinal Deformity
Research and Treatment
VuMedi Webinar
August 2013

Disclosures Shay Bess
• Consulting= Depuy/Synthes, Medtronic,
Allosource, K2M, Alphatec
• Royalties= Pioneer Spine, K2M
• Research support= Depuy/Synthes,
Medtronic, K2M
• Scientific advisory board= Allosource

Adult Spinal Deformity and Disability
• Traditional teaching= scoliosis is
not painful
• “Supporting evidence”
– Weinstein SL, et al. JAMA 2003
– Weinstein SL. JBJS 2000
• Results
– LIS =more pain and cosmetic vs
controls
– LIS 68%= little or moderate pain
(similar to controls)
– No effect on function, marital
status

“It is essential that
community physicians and
the public recognize that LIS
is likely to cause little
physical impairment other
than back pain and cosmetic
concerns.”

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7/31/2013

Adult Spinal Deformity and Disability
• Problems Weinstein Studies
1. No standardized HRQOL
– Modified pain, depression,
function and cosmesis scores
2. No sagittal analysis
– All patients= PA only
– Fundamental ASD
evaluation
3. Sagittal spinopelvic
malalignment
– Foundation pain and disability
spinal deformity
– Primary reason for not
diagnosing pain ASD

International Spine Study Group
• ASD research needs:
– Standardized clinical/radiographic
evaluation
– HRQOL correlations
– Best practice guidelines
• Clinical, economic, complications
• ISSG: Multi-center research group
– 13 sites
– Evaluation & treatment ASD
– Radiographic, psychological, HRQOL
– Cost effectiveness
– Heath impact vs. disease states
– Preoperative planning
– Complications

Site

Members

OHSC

Hart

UC Davis

Gupta, Klineberg

UCSF

Ames, Deviren,
Mummaneni

San Diego

Akbarnia,
Mundis, Eastlack

Colorado

Bess. Line

Baylor

Hostin, O’Brien,
McCarthy

Kansas

Burton

Johns Hopkins

Kebaish

Washington Univ

Buchowski

HSS

Boachie, Kim

NYU/HJD

Lafage, Schwab

Virginia

Shaffrey, Smith

ISSG Structure
• Independent private foundation (ISSGF 501 3c formed
2010)
• Online database (initiated 2009)
– Host site data entry; central data QA
• Centralized radiographic measures (initiated 2009)
– Upload to FTP server (NYU site); measurements
SpineView software
• Personnel
– Central coordinator
– Accountants and legal
– Health economists (JHU faculty and Baylor)

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7/31/2013

ISSG Projects
1. Prospective Operative vs. NonOp for ASD
– Consecutive enrollment ASD (scoliosis ≥20°, SVA≥5cm, PT≥25°,
or TK> 60°)
– Total =906; OP=415; NON=491
2. Three Column Osteotomy Database (3CO)
– Total =776 (data collection on going)
– Complete radiographic data=572
3. Proximal Junctional Failure (PJF); initiated 8/2012
– Retrospective analysis PJF in ASD
– Definition, incidence, risk factors, treatment
4. Prospective Cervical Deformity (PCD); initiated 1/1/2013
– Operative treatment adult PCD
5. Low grade adult spondylolisthesis; funding approved 2/2013
6. Cost effectiveness OP vs. NON for ASD; funding pending
7. Root cause analysis for success and failure of ASD surgery; pending

ISSG Abstract Productivity SRS/IMAST Submissions
52
50

Submitted
AcceptedPodium
Accepted Poster

45
40

40

35
30

27

25

19

20
13

15
10

7

10

9
5 6

6
3

5

5 6

6

0
2009

2010

2011

2012

2013

2012 ISSG Production and Topic Distribution
1; 4%

1; 4%

SRS-Schwab ASD
Classification
ASD Treatment/Outcomes

2; 7%

2; 7%

BMP Complications
PJK/PJF
7; 26%
Health Impact ASD
Cervical Deformity
7; 26%

3 Column Osteotomy
Surgical Complications
2; 7%
1; 4%

1; 4%

3; 11%

Coronal Alignment
Economics

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7/31/2013

2013 ISSG Production and Topic Distribution
Pelvic Fixation

1; 2%
6; 11%

10; 19%

ASD Treatment/Outcomes

BMP Complications
3; 6%

PJK/PJF
Health Impact ASD

2; 4%

2; 4%
3; 6%

Cervical Deformity
3 Column Osteotomy
Surgical Complications

5; 10%

Sagittal Alignment
4; 8%

1; 2%
2; 4%

Coronal Alignment
Economics

6; 12%

6; 12%

Psychology/Mental Health
MIS for ASD

Health Impact Comparison of Different
Disease States and Population Norms to
Adult Spinal Deformity (ASD): A Call for
Medical Attention
Kai-Ming Fu MD, Shay Bess MD, Frank Schwab MD, Christopher
Shaffrey MD, Virgine Lafage PhD, Justin Smith MD, Christopher Ames
MD, Oheneba Boachie-Adjei MD, Douglas Burton MD, Robert Hart MD,
Eric Klineberg MD, Richard Hostin MD, Gregory Mundis MD, Praveen
Mummaneni MD, and the International Spine Study Group.

North American Spine Society 2012 (Best Paper Nominee)
Scoliosis Research Socitey 2012
American Academy of Orthopaedic Surgeons 2013
American Academy of Neurosurgery 2012
AANS/CNS Joint Section 2013

Background Information
• SF-36 for ASD
– Little data comparing disease impact
ASD vs. other disease states
• Study Purpose
– Use SF-36 baseline values
– Consecutive cohort ASD patients
– No prior spine surgery
– Compare ASD SF-36 values
• United States general population
• United States generational norms
• United States disease specific
norms
– Compare disease impact using MCID
values

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7/31/2013

Materials and Methods
• Data collection
– Demographic, radiographic,
HRQOL
• ASD SF-36
– Physical component score (PCS)
– Mental component score (MCS)
– Compared to United States (US)
• Total population norms
• Age generational norms
• Disease specific norms
– Norm based scoring (NBS)
– MCID values (cross-sectional)
• PCS= 3 NBS points
• MCS= 3 NBS points

Results: Total

• ASD Demographic &
Radiographic
– N=497
– Age 50.4 years
– Scoliosis= 45.3°
– PT= 18.8°
– SVA= 19.9mm
• ASD vs. U.S. total
population
– PCS=-9 NBS (3 MCID)
– MCS= similar
• ASD vs. U.S. generational
norms: PCS
– Minimum 2 MCID lower
– <25th percentile
– All generations except
18-24yrs; (-2.2 NBS)
– More rapid decline than
U.S. general

ASD (n=497)

Mean values (SD)

Generational
Age Groups
(n=total ASD
patients)

ASD
US
years
PCS;Age;
Population
NBS
PCS; NBS
valueBMI value
(SD)

PCS
Difference
(percentile
US general
population)

ASD
MCS;
NBS
value
(SD)

18-24 years
(n=42)

51.3
53.5
(8)PT; degrees

25-34 years
(n=75)

-2.2
(<50th )

48.2
(10.5)

46.9PT-LL53.6
-6.7
mismatch;
(9.2)degrees
(<25th )

50.8
(9.6)

35-44 years
(n=52)

42.3Maximal
52.3scoliosis;
-10
(9.5)
(<25th )

49.7
(9.0)

45-54 years
(n=88)

41.9
49.7
SF-36 PCS
(10.5)

-7.8
(<25th )

50.4
(10.9)

55-64 years
(n=138)

MCS
38.7SF-3647.4
(10.6)
ODI

-8.7
(<25th )

47.1
(13.1)

65-74 years
(n=73)

33.6SRS-22;
44.7total score
-11.1
(10.3)
(<25th )

50.9
(11.7)

≥75 years
(n=29)

31.7SRS-22r;
39.9 pain -8.2
(9.5)
(<25th )

52.8
(8.5)

Total
population
(n=497)

40.9
(11.2)

49.4
(11.3)

SVA; mm

degrees

SRS-22r; function

SRS-22r; self-image
50

-9.1
(<25th )

US

MCS

50.4
(16.9)difference
Population
MCS; NBS
25.6
value(6.4)
19.9
(58.1) +2.2
46.1
18.8 (10.2)
49.1(17.6) +1.7
4.21
49.1(18.3) +0.6
45.3
50.6

-0.2

50

-0.6

40.8 (11.2)
49.4
51.6(11.3) -4.5
27.0 (18.6)
52.8(0.7) -1.9
3.39
3.40 (0.8)
50.2(0.7) +2.6
2.94
3.31 (0.8)

SRS-22; mental health

3.86 (0.8)

Leg Pain; NRS

2.63 (3.1)

Results: ASD No Other Comorbidities
• ASD No Other
Comorbidities vs. U.S.
Total and Generational
Norms
• PCS
– Minimum one MCID
lower U.S. norms
– <25th percentile
– ASD generations
(except 18-24 yr)
– More rapid decline
than U.S. general
• MCS
– Similar

Generational
Age Groups
(n=total ASD
patients)

ASD PCS;
NBS
value (SD)

US General
Population
PCS; NBS
value

PCS Difference
(percentile US
general
population)

ASD MCS:
NBS value
(SD)

US General
Population
MCS; NBS
value

18-24 years
(n=30)

52.7
(7.3)

53.5

25-34 years
(n=58)

46.8
(9.6)

53.6

-0.8 (<50th )

48.8
(10.7)

46.1

-6.5 (<25th )

51.2 (8.9)

35-44 years
(n=34)

43.2
(10.3)

49.1

52.3

-9.1 (<25th )

50.2 (9.6)

45-54 years
(n=47)

49.1

43.2
(10.8)

49.7

-6.5 (<25th )

49.9 (11.3)

50.6

55-64 years
(n=57)

42.4
(9.7)

47.4

-5.0 (<25th )

48.9 (11.4)

51.6

65-74 years
(n=14)

35.8
(11.1)

44.7

-8.9 (<25th )

51.9
(12.2)

52.8

≥75 years
(n=6)

36.8
(10.8)

39.9

-3.1 (<25th )

51.4 (9.3)

50.2

Total
population
(n=246)

44.4
(10.5)

50

-5.6 (<25th )

50.2
(10.5)

50

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7/31/2013

Results: ASD vs. U.S. Disease Norms
• ASD vs. U.S Healthy and
Disease Norms
• PCS
– Healthy US<14.5 NBS
(4 MCID )
– Back pain/Sciatica
<4.8 NBS (one MCID)
– Hypertension<3.1 NBS
(one MCID)
– Similar
• Cancer
• Diabetes
• Heart disease
• Limited use arms or
legs
• Lung disease

Disease State

US Total Population

PCS;
mean
NBS
points

MCS;
mean
NBS
points

50

49.9

US Healthy Population

55.4

52.9

ASD

40.9

49.4

Back Pain

45.7

47.6

Cancer

40.9

47.6

Depression

45.4

36.3

Diabetes

41.1

47.8

Heart Disease

38.9

48.3

Hypertension

44.0

49.7

Limited Use Arms
Legs
Lung Disease

39.0

43.0

38.3

45.6

Disease State Correlates for Type and
Severity of Adult Spinal Deformity;
Assessment Guidelines for Health Care
Providers
Shay Bess, Kai-Ming Fu, Virginie Lafage, Frank Schwab, Christopher
Shaffrey, Christopher Ames, Robert Hart, Eric Klineberg, Gregory
Mundis, Richard Hostin, Douglas Burton, Munish Gupta, Oheneba
Boachie-Adjei, Justin Smith, and the International Spine Study Group.

20th International Meeting on Advanced Spine Technologies
Annual Meeting
Vancouver, Canada
July 2013

Purpose, Materials and Methods
• Study Purpose
– Compare types/severity ASD
– Other disease states
• Materials and Methods
– Consecutive cohort ASD patients
– No prior surgery
– ISSG prospective, multi-center database
– ASD organized
• Sagittal vs. coronal deformity
• Deformity severity
– ASD baseline SF-36 compared
• United States general population
• United States disease specific norms
– Disease impact compared using MCID
values

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7/31/2013

Results: ASD Deformity Type and Disability
• ASD Demographic
– N=497
– Age 50.4 years
– Scoliosis= 45.3°
– PT= 18.8°
– SVA= 19.9mm
• ASD PCS
• PCS worsens
– Curve location
– Sagittal
malalignment
• Multivariate analysis
worsening PCS
– PI-LL (R=-0.44)
– SVA (R=-0.40)
– PT (R=-0.38)

60

Deformity
Type and Mean
ASD
ASD (n=497)
values (SD)
Disability:
SF-36 PCS50.4 (16.9)
Age;
years

50

40

BMI
SVA; mm

25.6 (6.4)
19.9 (58.1)

PT; degrees
PT-LL mismatch; degrees

18.8 (10.2)
4.21 (17.6)

Maximal scoliosis; degrees

45.3 (18.3)

SF-36 PCS
SF-36 MCS
ODI
SRS-22; total score
SRS-22r; function
SRS-22r; pain
SRS-22r; self-image

40.8 (11.2)
49.4 (11.3)
27.0 (18.6)
3.39 (0.7)
3.40 (0.8)
2.94 (0.7)
3.31 (0.8)

SRS-22; mental health

3.86 (0.8)

30

20

10

0
US
ASD total Scoliosis Scoliosis Scoliosis Scoliosis Scoliosis SVA >10 SVA >10;
general
MT
L
>20; SVA <20; SVA
Leg Pain;
NRSTL
2.63 (3.1) Scoliosis
<5
>5
L

Results: ASD Type, Severity and Disease Correlates
50

ASD PCS

45.5

Disease 1 PCS

45
40.9

Disease 2 PCS

40

36.7

35
30.4
30

28.5

29.3
24.7

25
20
15
10
5
0
US general

ASD total vs
cancer and
diabetes

MT curve vs. L curve vs. OA SVA >5 vs.
SVA>10 vs.
L curve +
L curve +
US total and
and heart
25th OA and
25th limited SVA>5 vs. 25th SVA>10= No
back pain
disease
25th RA
vision and 25th limited use
comparable
lung disease
arms legs
disease value

ASD Deformity Type:
• Scoliosis Thoracic=2 MCID below General Population
• Scoliosis Lumbar =5 MCID below General Population
•L curve + Severe SSM; SVA>10=PCS lower ANY RECORDED VALUE!!

Conclusions and References
• ASD worsening impact
– Deformity location
– Deformity type
– Deformity severity
• ASD vs. other disease states
– Greater impact more recognized diseases
• Future work
– Dissemination: medical community &
Federal funding sources
– Cost effectiveness ASD vs. other disease
states
• References
– Schwab F, Dubey A, Pagala M, et al. Adult
scoliosis: a health assessment analysis by SF36. Spine 2003;28:602-6.
– Weinstein SL, Dolan LA, Spratt KF, et al. Health
and function of patients with untreated idiopathic
scoliosis: a 50-year natural history study. Jama
2003;289:559-67.

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7/31/2013

Thank You

8

8/2/2013

Proximal Junctional Failure:
What is it?
Can it be prevented?
Novel Approach with VEPTR
Robert Hart, MD
OHSU Orthopaedics
Portland OR

Conflicts





Consultant Depuy Spine, Medtronic
Royalties Seaspine, Depuy
Stockholder SpineConnect
Research/Fellowship Support Depuy,
Medtronic, Synthes, OREF, MRF, ISSG

Proximal Junctional Failure =
Post-operative Fracture and/or Soft Tissue Disruption
at Upper Instrumented or Next Adjacent Segment
Following Long Instrumented Fusion
“Topping Off Syndrome”
Proximal Junctional Fracture

Distinct from

Fracture above all
Pedicle Screw Construct
(FPSC)

“Proximal Junctional
Kyphosis”

Proximal Junctional Acute
Collapse

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8/2/2013

Increasingly Recognized and
Described Following Long
Lumbar Spine Fusions







Etebar and Cahill, J Neurosurg, 90:163-9, 1999
Dewald and Stanley, Spine, 31:S144-51, 2006
Hart et al., TSJ, 8:875-81, 2008
Kim et al., Spine, 32:2653-61, 2007
O’Leary et al., Spine, 34:2134-9, 2009
Watanabe et al., Spine, 35:138-45, 2010

Case Example 1:
70 YO Woman
1 Level TLIF

2 Year Follow-up
Fracture T10 (UIV)
“Reciprocal Change”

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8/2/2013

Case Example 2:
77 YO Woman
S/P L2-S1 Fusion

6 weeks Post-op

Fracture of UIV
Hardware Failure
Posterior Column
Disruption

5 Year
Follow Up
Is Perfect
Balance
Needed?

3

8/2/2013

Case Example 3:
70 yo Woman
S/P Laminectomy PSF L2-L5

Risk Factors
(Hart/ISSG, IMAST, 2012)
 Age
Preop TK for all comparisons
 Pre-op SVA and PT for UT
 Pre-op LL, PI-LL, and SS for TL
 Use of PSO for UT
 Change in LL and PI-LL for TL
Significant Increased Rate of Revision




Potential Preventive Techniques
• Vertebral Augmentation
• Proximal Hooks
• Moving Junction Cranial
• “Tuning” Correction
• “Laying In” Rods to Upper Screws
• Limit Proximal Dissection

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8/2/2013

Vertebral Augmentation
72 YO Woman
Short Stature
Multi-focal DJD
S/P Laminectomy
Pain Pump

Vertebral Augmentation
S/P T10-Pelvis
Screw Failure/Fracture
Despite Kyphoplasty

Vertebral Augmentation

5

8/2/2013

Move Junction Cranial

Move Junction Cranial

Vertebral Augmentation
73 YO Woman
Degenerative
S/P Laminectomy
Pain Pump

6

8/2/2013

Vertebral Augmentation

Vertebral Augmentation

DJD at
Proximal Disk
2 Years
Post-op

Proximal Hooks

7

8/2/2013

Proximal Hooks

Summary – Vertebral
Augmentation




Reduces Incidence But Not to Zero
 Avoids Midline Dissection
May Accelerate Degenerative Disease
 Cost
 Some Fuss in OR

Summary-Proximal Hooks




No Evidence to Support Reduced
Incidence
 Mechanically Questionable
Doesn’t Avoid Proximal Dissection
 Is Simple to Include

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8/2/2013

SummaryMove Junction Cranial
No Evidence to Support Reduced
Incidence
Upper Thoracic Failures May be Worse
 Significantly More Surgery
 Doesn’t Avoid Midline Dissection




“Tuning” Correction


ISSG Data Shows Greater PI-LL Mismatch
for TL Junction PJF Patients




Overcorrection May Also Be Harmful

Clearly Important Surgical Goal But May
Not Always Be Attainable

“Laying In” Proximal Rod


Makes Good Mechanical Sense




Easy To Do

Doesn’t Reduce Proximal Dissection


Data Lacking

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8/2/2013

Limiting Proximal Dissection




Makes Good Biologic Sense

Doesn’t Change Mechanical Effects




Some Fuss in OR

Data to Support Pending

VEPTR Device
Indications
The device is indicated for the treatment of
thoracic insufficiency syndrome (TIS) in
skeletally immature patients. TIS is defined as
the inability of the thorax to support normal
respiration or lung growth. For the purpose of
identifying potential TIS patients, the
categories in which TIS patients fall are as
follows:
– Flail chest syndrome
– Constrictive chest wall syndrome, including
– Rib fusion and scoliosis
– Hypoplastic thorax syndrome, including
– Jeune’s syndrome
– Achondroplasia
– Jarcho-Levin syndrome
– Ellis van Creveld syndrome
– Progressive scoliosis of congenital or
neurogenic origin without rib anomaly

Proximal Rib Fixation with
VEPTR
Reduces Proximal Dissection –
Good Biological Sense
 Extends Moment Arm Lateral –
Good Mechanical Sense
 Allows Other Surgical Techniques
 Some OR Fuss


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8/2/2013

VEPTR Device - Technique


Rib Attachment UIV+1 Level


Separate Lateral Incisions


Blunt Muscle Dissection


Offset Connection

Personal Experience
 6 Patients
5 Female/1 Male
 Age Range 62-77
 BMI 20.4-42.0




1 PJF Without Collapse
 1 Distal Fracture

Case 1:
62 YO Woman
Degenerative
Normal DEXA
No Prior Surgery

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8/2/2013

UIV
Compression
Fracture

Case 3
69 YO Woman
Degenerative
Normal DEXA
No Prior Surgery

12

8/2/2013

Case 4
67 YO Woman
BMI 42
Osteopenia
Multiple Prior Surg

Conclusions
PJF is a Serious Complication
 Risk Profile Defined
 Methods to Reduce Frequency
 No Technique Eliminates PJF
Further Development/Study Needed




13

8/2/2013

THANK YOU

14

8/4/2013

Christopher Ames MD
Professor
Director of Spine Tumor and Deformity Surgery
UCSF Department of Neurosurgery

Normative and Spinal
Pelvic Correlations

Alignment Study Normal
Population


55 asymptomatic volunteers (27 men, 28 women; mean age=45
years) were evaluated by full-length standing radiographs using a
standardized protocol. All radiographs were analyzed using
validated image analysis software for C2-C7 cervical lordosis
(CL), T4-T12 thoracic kyphosis (TK), L1-S1 lumbar lordosis
(LL), pelvic tilt (PT), sagittal vertical axis (SVA), pelvic incidence
(PI) and PI-LL mismatch. Statistical analysis was performed for
the study population and after stratification by age (20-39yo, 4059yo and ≥60yo).

Spine Focus Issue 2013
Age related cervical and spino-pelvic parameters variations in a volunteer population
Benjamin Blondel, MD1,2 Frank Schwab, MD1 Christopher Ames, MD3 Jean-Charles Le Huec,
MD PhD4, Justin S. Smith, MD PhD5 Jason Demakakos, MS1 Bertrand Moal, MS1 Patrick
Tropiano, MD PhD2 Virginie Lafage, PhD1

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8/4/2013

Normal Cervical Alignment?

2

8/4/2013

Background


Sagittal malalignment
linked to disability and
unfavorable HRQOL
scores



Glassman et al found that
sagittal alignment using C7
plumb line is most reliable
predictor of HRQOL
scores

Glassman Data Spine 2005

Changing our Treatment Strategies for all T/L patients

The SRS-Schwab Classification of
ASD (2012)

Jean Dubousset

3

8/4/2013

Prospective analysis including pelvis
Schwab, Lafage, Shaffrey, Bess, Ames
125 patients

SpineView®
300 parameters

492 patients

• Lafage Schwab
• Spine 2009

• ISSG
• SRS 2011

• All Curves
• SRS, ODI
• Xray & clinical
analysis
• One site

• All curves
• SRS, ODI
• Xray vs clinical
correlation
• Multi-center

What are the disability / pain generators ?

* Frank Schwab

PI minus LL
• #1 most important parameter

LL

• Correlation with
– SRS (appearance, activity, total)
– ODI (Walk, stand)
– SF12 (PCS)

• r-values

PI

– 0.42 30°

N No Coronal Curve
All coronal curves <30 °

0 : within 10°
+: moderate 10-20°
++ : marked >20°

Global alignment
0 : SVA < 4cm
+ : SVA 4 to 9.5cm
++ : SVA > 9.5cm

Pelvic Tilt
0 : PT<20°
+ : PT 20-30°
++ : PT>30°

ISSG Cervical Deformity
Classification

Jean Dubousset

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8/4/2013

Cantilever Load of Head
4.5kg
4.5kg

4.5kg

2
7

L
B
P
High
PT

Goals:



Evaluate relationship between sagittal alignment of
cervical spine and patient-reported HRQOL scores
following multi-level posterior cervical fusion
 Identify radiographic parameters in cervical spine
most predictive of postoperative disability


MATERIALS AND METHODS


Retrospective analysis (2006 – 2010)



Clinical Outcomes






NDI
SF-36 PCS
VAS

Radiographic Outcomes






C2-C7 Lordosis
C2-C7 SVA
T1 Slope
T1 Slope – C2-C7 Lordosis

6

8/4/2013

Patient Demographics





113 patients (M=61, F=52)
Mean age: 59 ± 12 years
Most common indications for long segment cervical
fusion:








Cervical stenosis (n = 65)
Myelopathy (n = 38)
Deformity (n = 14)
Degenerative disc (n = 13)

Mean number of levels fused: 5.6 ± 1.9
Average follow-up time: 187 ± 108 days

Cervical Measurements
CGH-C7 SVA

C1-C7 SVA
C1-C2 lordosis

C2-C7 SVA

C2-C7 lordosis

Measurement of cervical SVA


C2-C7 SVA



Distance between
plumb line
dropped from
centroid of C2
and C7

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8/4/2013

Significant Correlations: Radiographic
Measures and HRQOL Scores
Radiographic
Measure

HRQOL
Score

No. Cases

Pearson's
coefficient

P-value

C1-C7 SVA

NDI

108

0.1863

0.0535

C1-C7 SVA

PCS

58

-0.4097

0.0014*

C2-C7 SVA

NDI

108

0.2015

0.0365*

C2-C7 SVA

PCS

58

-0.4262

0.0009*

CGH-C7 SVA

NDI

108

0.1873

0.0522

CGH-C7 SVA

PCS

58

-0.3613

0.0053*

Correlation between C2-C7 SVA and
NDI Scores
35
30

NDI Score

25
20
15
10
5
0
<10

20-30

30-40

40-50
50-60
C2-C7 SVA (mm)

60-70

>70

Background T1-CL


In the lumbar spine, the single best
predictor of disability is a mismatch
greater than 11 degrees between
lumbar lordosis and pelvic incidence
(LL–PI > 11 degrees).



The T1 slope has been previously
suggested as an important factor in
influencing overall spinal sagittal
alignment, and increasing T1 slope
has been shown to significantly
correlate with greater sagittal
malalignment of the dens (Knott et al,
2010).

8

8/4/2013

Concept CT “Incidence”-T1 slope

T1

T1

Significant Correlations: Radiographic
Measures
Radiographic Measure

Radiographic Measure

Pearson's
coefficient

P-value

C2-C7 Lordosis

T1 Slope

0.38

<0.0001*

C2-C7 SVA

T1 Slope

0.44

<0.0001*

C2-C7 SVA

T1 Slope – C2-C7 Lordosis

0.45

<0.0001*

Correlation between C2-C7 SVA and
T1 Slope – C2-C7 Lordosis
70

T1 slope – C2-C7 lordosis (deg)

60
50
40

y = 0.3732x + 6.9998
R² = 0.1986

30
20
10
0
-20

0

20

40

60

80

100

120

-10
-20

C2-C7 SVA (mm)

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8/4/2013

Regression Analysis for Disability
Thresholds


Significant correlations further analyzed between C2-C7 SVA
and NDI scores (n = 108)



Logistic regression model predicted threshold value of 41 mm
for C2-C7 SVA (χ2 = 6.60, p = 0.0102)



Linear regression predicted threshold C2-C7 SVA value of 37
mm for a raw NDI score of 25 (r2 = 0.04, p = 0.0365)



C2-C7 SVA value of 40mm corresponded to a T1 slope – C2C7 lordosis value of 21.9 deg.

DISCUSSION


Positive cervical sagittal malalignment, measured by
C2-C7 SVA, negatively affects HRQOL scores
following multi-level posterior cervical fusion at
intermediate follow-up



Study proposes a C2 plumb line greater than ~40
mm from posterior superior aspect of C7 (in
standing position) suggests clinical concern of
cervical sagittal malalignment that may negatively
impact HRQOL

DISCUSSION







The greater the T1 slope, the greater C2-C7
lordosis (perhaps a compensatory mechanism?)
The greater the mismatch between T1 slope and
C2-C7 lordosis, the greater the sagittal malalignment
cSVA >4cm
T1 slope –CL > 20 = cSVA>4cm

10

8/4/2013

Question?


Is it enough to simply decompress patients with
myelopathy and kyphosis or is it more beneficial
to also correct their deformity?
For neck pain and disability
For myelopathy improvement
 For adjacent segment disease






If so, what parameters do we use?
How do we do it if the spine is rigid?

Cervical alignment: myelopathy



Common etiology: multi-level spondylosis
Less attention to progressive cervical
kyphosis – also associated with myelopathy

11

8/4/2013

Association of Myelopathy
Scores with Cervical Sagittal
Balance and Normalized
Spinal Cord Volume
Analysis of 56 Preoperative cases from the AOSpine
North America Myelopathy Study
Justin Smith, MD, PhD
Virginie Lafage, PhD
Christopher Shaffrey, MD
Frank Schwab, MD
Dan Riew, MD
VincentTraynelis
Alex Vaccaro, MD, PhD
*Michael Fehlings, MD, PhD
Christopher Ames, MD

Results: Correlations between mJOA and
Sagittal Radiographic Parameters

Self Image, Function, CBVA

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8/4/2013

Impact of Subjacent Alignment

PT and CL

Subjacent Alignment






Cervical Alignment
depends on subjacent
alignment
Pelvic retroversion and
lumbar hyperlordosis in
primary cervical
deformity
Cervical correction
results in improvement
in normalization of
compensatory
parameters

13

8/4/2013

Example Case—Correction of
Cervical Hyperlordosis with
Lumbar PSO

14

8/4/2013

Cervical Deformity
Classification
Deformity Descriptor

CT- Primary Sagittal Deformity
Apex at Cervico-Thoracic
Junction
T- Primary Sagittal Deformity
Apex in Thoracic Spine
S- Primary Coronal Deformity
(C2-C7 Cobb > 15°)
CVJ- Primary Cranio-Vertebral
Junction Deformity

Horizontal Gaze
0: CBVA < ° 10
1: CBVA 10 to 25°
2: CBVA > 25 °

5 Modifiers

C- Primary Sagittal Deformity
Apex in Cervical Spine

C2-C7 sagittal vertical axis (SVA)
0: C2-C7 SVA < 4cm
1: C2-C7 SVA 4 to 8cm
2: C2-C7 SVA > 8cm

Cervical Lordosis Minus T1 Slope
0: CL-T1 < ° 15
1: CL-T1 15-to 20 °
2: CL-T1 >20 °
Myelopathy
0: mJOA=18 (None)
1: mJOA=15-17 (Mild)
2: mJOA=12-14 (Moderate)
3: mJOA<12 (Severe)

SRS-Schwab Classification
 T, L, D, or S: Curve Type
A, B, or C: LL minus PI
L, M, or H: Pelvic Tilt
N, P, or VP: C7-S1 SVA

Treatment of Adult Cervical Deformity Based
on Classification?

15

8/4/2013





Inclusion criteria: (Must meet all criteria as outlined in 1-4):
1) Adult patients (≥18 years old at time of enrollment)
2) Cervical deformity- must meet one or more of the following criteria:







Cervical kyphosis (C2-7 Cobb angle >10°)
Cervical scoliosis (coronal Cobb angle >10°)
cSVA > 4 cm
CBVA > 25°

3) Plan for surgical correction of cervical deformity

Nomenclature—
Cervical Osteotomy
Classification

Osteotomy Grades and Surgical Approach Modifiers-Schwab
Resection

Description

Surgical
approach

Grade 1

Partial Facet Joint

Resection of the inferior facet and joint capsule
at a given spinal level

A/P
(a nterior soft ti ssue
rel ease combined
wi th posterior
res ection)
P (pos teri or)

Grade 2

Complete Facet
Joint

Both superior and inferior facets at a given
spinal segment are resected; other posterior
elements of the vertebra including the lamina,
and the spinous processes may also be resected

Grade 3

Partial Body

Grade 4

Partial Body and
Disc

Partial wedge resection of a segment of the
vertebral body and a portion of the posterior
vertebral elements
wedge resection through the vertebral body;
includes a substantial portion of the vertebral
body, posterior elements and includes resection
of at least a portion of one endplate with the
adjacent intervertebral disc

A/P
(anterior soft tissue
release combined
with posterior
resection)
P (posterior)
A (anterior release)
P (posterior release)
A/P (both)

Grade 5

Complete Body
and Disc

Complete removal of a vertebral body and both A (anterior release)
P (posterior release)
adjacent discs (rib resection in the thoracic
A/P (both)
region)

Grade 6

Multiple Adjacent
Body

Resection of more than one entire vertebral
body and discs. Grade 5 resection and additional
adjacent vertebral resection

A (anterior release)
P (posterior release)
A/P (both)

A (anterior release)
P (posterior release)
A/P (both)

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8/4/2013

Osteotomy Grade Representation-Schwab

Grade 1
Grade 2

Grade 3
Grade 4

Grade 5
Grade 6

Grade 7

Resection

Description

Surgical
approach

Partial Facet
Resection or ACD
Complete Facet
Joint/Ponte
Osteotomy
Partial Body,
Corpectomy
Complete
Uncovertebral
Joint Resection to
Foramen
Transversarium
Opening Wedge
Osteotomy
Closing Wedge
Osteotomy
Complete
Vertebral Column
Resection

Anterior cervical discectomy including partial
uncovertebral joint resection, posterior facet
capsule resection or partial facet resection
Both superior and inferior facets at a given spinal
segment are resected; other posterior elements of
the vertebra including the lamina, and the spinous
processes may also be resected

A, P, PA, AP, APA, PAP

Partial Corpectomy Including discs above and
below
Anterior osteotomy through lateral body and
uncovertebral joints and into foramen
transversarium

A,P, PA, AP, APA,
PAP

A,P, AP, PA, APA,
PAP

A,P, AP, PA, APA,
PAP

Complete posterior element resection with
osteoclastic fracture and open wedge creation

A, P, AP, PA, APA,
PAP

Complete posterior element resection and pedicle
resection with closing wedge creation

A, P, AP, PA, APA,
PAP

Resection of one or more entire vertebral body
and discs including complete uncovertebral joint
and posterior lamina and facets

A, P, AP, PA, APA,
PAP

Case 11
Operative procedure:
Posterior spinal fusion with
instrumentation from C2-T2,
multilevel complete facet
resection

17

8/4/2013

Case 19
Operative procedure:
Posterior instrumentation from
C2-T8, pedicle subtraction
osteotomy at C7, posterior
spinal osteotomy at C6-T1

Case 16
Stage 1: C4-5 corpectomy followed by
Stage 2: Posterior spinal fusion with instrumentation from C2-T2 and ponte osteotomy

+

ISSG Cervical Osteotomy
Classification


JNS Spine September 2013

Analysis of major
osteotomy +
approach modifier
yielded a
classification that
was “almost perfect”
with average intrarater reliability of
0.91 (0.82-1.0) and
inter-rater reliability
of 0.87 and 0.86 for
the 2 reviews.

18

8/4/2013

Further Reading

19

8/4/2013

Surgical Treatment of Pathological Loss of Lumbar
Lordosis (Flatback) in the Setting of Normal SVA
Achieves Similar Clinical Improvement as Surgical
Treatment for Elevated SVA
Justin S. Smith, Manish Singh, Eric Klineberg, Christopher I.
Shaffrey, Virginie Lafage, Frank Schwab, Themi Protopsaltis,
David Ibrahimi, Justin K. Scheer, Greg Mundis, Munish Gupta,
Richard Hostin, Vedat Deviren, Khaled Kebaish, Robert Hart,
Doug Burton, Shay Bess, Christopher Ames

Disclosures
• Biomet: consultant, honorarium for
teaching
• Medtronic: consultant, honorarium
• DePuy: consultant, research study
group support
• Globus: honorarium for educational
course
• AANS/CNS Joint Spine Section:
research grant support

Background
• Sagittal spinal malalignment

is a
key driver of pain and disability
in adult spinal deformity

• More recently has become clear
that SVA alone does not fully
account for global alignment

• Role of the pelvis as a key
regulator of spinal alignment
and a source of compensation

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8/4/2013

SDSG Radiographic
Measurement Manual

Global Sagittal
Alignment
SVA=Sagittal Vertical Axis

+26 cm

Background

Ames CP, et al. JNS Spine 16:547-64, 2013.

Pelvic Incidence and Lordosis
Large PI
Horizontal Sacrum
Marked, long lordosis

Small PI
Vertical Sacrum
Flat Lordosis

Pragmatic
Estimate:
LL = PI +/- 10deg

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8/4/2013

Background
• Based on 492 adults with spinal
deformity, the top radiographic
parameters with strongest
correlations to HRQOL scores:

PI minus LL

#1. PI minus LL
#2. SVA (C7 plumbline)

#3. Pelvic tilt (PT)
Schwab FL, et al. Spine 38(13):E803-12, 2013.

Background

SVA = +3.9cm
SVA
= +21cm
PI-LL
= 5°
PI-LL = 54°

• “Sagittal imbalance” (SVA
>5cm) is a recognized
driver of disability and a
primary indication for
surgical correction

• Multiple studies have
demonstrated improvement
in HRQOL with correction
of “sagittal imbalance”

Background

SVA = +1.6cm
PI-LL = 25°

• Subset of patients with sagittal
spino-pelvic malalignment and
flat back deformity but remains
sagittally compensated with
normal SVA
• Few data exist for patients
with “compensated flatback”
(SVA <5cm, PI-LL >10°)
• Does surgical treatment offer
improvement in HRQOL?

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8/4/2013

Decompensated

Compensated

Objective
• To compare baseline disability and
treatment outcomes for patients
with sagittal spino-pelvic
malalignment who are:
▪

Compensated
(PI-LL>10° & SVA<5cm)

▪

Decompensated
(SVA>5cm)

Methods
• Study design: Prospective, multicenter (ISSG), consecutive cases
• Inclusion criteria:
- ASD (age >18)
- >5 levels posterior instrumentation
- min 1yr follow-up
- SVA>5cm (decompensated) OR
SVA<5cm with PI-LL>10°
(compensated)
• Analysis: Comparisons between
compensated and decompensated

4

8/4/2013

Patient Population

Parameter
Mean age, years (SD)
Gender, percent women
Mean BMI (SD)
Mean Charlson
Comorbidity Index (SD)
Mean pain score, 0-10 (SD)
Back pain
Leg pain

SVA > 5cm
(n=98)

SVA <5cm &
PI-LL >10°
(n=27)

P-value

62.9 (12.4)
76
28.6 (5.1)

55.1 (12.1)
93
26.6 (5.9)

0.004
0.063
0.097

1.6 (1.7)

1.1 (1.2)

0.083

7.7 (2.0)
4.6 (3.2)

6.8 (2.4)
4.6 (3.6)

0.060
0.97

Change from Baseline to 1yr
Decompensated Group
P<0.001
P<0.001

P<0.001

P<0.001
P<0.001

Change from Baseline to 1yr
Compensated Group
P=0.005

P=0.034

P<0.001

P<0.001

P=0.009

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8/4/2013

Change from Baseline to 1yr
Decompensated Group
All comparisons: P<0.001

Change from Baseline to 1yr
Compensated Group
All comparisons: P<0.007

Change from Baseline to 1yr
All comparisons: P>0.24

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8/4/2013

Percent Reaching MCID
P=0.28

P=0.15
P=0.98
P=0.87 P=0.42

P=0.49

Conclusions
• Sagittal spino-pelvic malalignment is
a key driver of pain and disability in
adult spinal deformity.
• Surgical correction of sagittal spinopelvic malalignment for compensated
and decompensated patients had
similar radiographic and HRQOL
improvement.
• PI-LL mismatch should be evaluated
for adult deformity patients and can
be considered a primary surgical
indication.

7

8/4/2013

R EA LIGNMENT FA ILURE
W HAT THE R ESEA RCH S HOWS A ND F UTURE
D IRECTIONS FOR A NA LYSIS A ND
I MPROVEMENT
Virginie Lafage, PhD
Frank Schwab, MD

D ISCLOSURES



Virginie Lafage







(a) SRS
(b) Medtronic
(c) Nemaris
(f) DepuySpine, Medtronic, K2M, Globus

Frank Schwab





1

(a) DePuy Spine, Medtronic
(b) Medtronic
(c) Nemaris
(f) Medtronic

a.
b.
c.
d.
e.
f.

Grants/Research Support
Consultant
Stock/Shareholder
Royalties
Board member
Payment for lectures

C ORRECTION OF S AGITTAL P LANE
D EFORMITY
P ERFORMANCE R EVIEW

1

8/4/2013

S A GITTA L P LA NE D EFORMITY
Prospective Surgical ASD database

~60% of all
ASD patients
with sagittal
deformity

N UMBER

OF

ASD P ROCEDURES INCREA SED
BY 157% IN 10 YEA RS

Number of discharges with at least one diagnosis of
spinal curvature' (ICD-9 code 737.0 to 737.9)
250,000
200,000
150,000

Children

100,000

Adult

50,000
0
1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009

Healthcare Costs and Utilization Project (HCUP http://hcupnet.ahrq.gov),

U TILIZATION

# Wedge Osteotomies
(77.29 ICD-9-CM)

Wedge Osteotomies by age group
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%

800
700
600
500
400
300
200
2003

2004

2005

2006

2007

2008

OF WEDGE OSTEOTOMIES

2009

2010

Increases on 275% in less than 10 years
~250 procedures in 2003
~700 procedures in 2012

>65
45-64
18-44

2003 2004 2005 2006 2007 2008 2009 2010

Increase proportion of patients >65yo
~20% in 2003
~40% in 2012

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8/4/2013

R A DIOGRA PHIC “D RIVERS ”

OF DISA BILITY ?

Schwab, Lafage, Shaffrey, Bess, Ames …

125 patients

SpineView®
300 parameters

492 patients

• Lafage Schwab
• Spine 2009

• ISSG
• SRS 2011

• All Curves
• SRS, ODI
• Xray & clinical
analysis
• One site

• All curves
• SRS, ODI
• Xray vs clinical
correlation
• Multi-center

A DULT D EFORMITY = D ISA BILITY ?

Regional
Global

Loss of lordosis
Versus PI

SVA

Compensatory
Pelvic tilt

Goals
PI-LL < 10°

SVA < 5cm

A CHIEVING



REALIGNMENT

G OALS

As a Surgeon, I know the
“alignment objectives”






PT < 20-25°

LL within 10deg of PI
PT <20-25deg
SVA < 5cm

As a Surgeon, I can change
focal alignment




Impact on region
Impact on global
Reset compensation

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8/4/2013

E FFECTIVENESS

OF SA GITTA L CORRECTION



Outcomes after major realignment
surgeries

Under-correction (SVA)




Analysis of risk factors





40% at 3m following index
procedure

Lack of lordosis versus PI
80% can be predicted

Root Cause analysis?






Poor planning
Poor execution,
Intra-op complications
Unrealistic Planning
Poor intra-op feedback ….

R A DIOGRA PHIC S URGICA L O UTCOMES
Prospective Surgical ASD database (pre / 1y post-op)

100%
90%
80%
70%

High Frequency of
inadequate sagittal
correction

60%
50%
40%
30%
20%
10%
0%

Max Cobb

Radiographic
Correction

2

Cor_Imb

Lack of
Correction

SVA

Radiographic
Deterioration

IL

PT

Where does
the ‘problem’
come from?

No Pre or Post
Deformity

R OOT C AUSE A NALYSIS

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8/4/2013

L UMBA R R EA LIGNMENT FA ILURES
Risk factors for realignment
failure?
Sagittal Correction
 HRQOL
Improvement

PSO patients

< 5cm

Sub-optimal SVA
Correction



“ FA ILED ”

GROUP

Lordosis, kyphosis

More Pre-op spino-pelvic mal-alignment






OF THE

Same Pre-op curvatures




‘Failed’
Rx Outcome

‘Successful’
Rx Outcome

A NA LYSIS

> 10cm

Post-op
SVA?

Proportion Lordosis vs Pelvic Incidence
Pelvic retroversion
SVA (C7 plumbline)

Same Surgical Procedure !
Need to establish a quality control
process

Q UALITY


Evaluate the severity of the deformity
Identify / Quantify compensatory mechanisms

Pre-op Planning to reach alignment objectives



Changes in lumbar lordosis
Changes in thoracic kyphosis





Fused segments
Reciprocal changes

Intra-op monitoring





P ROCESS

Pre-op Analysis





CONTROL

Patient ;-)
Regional alignments

Post-op Analysis



Repeat Pre-op analysis
Comparison with planning and intra-op xrays

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8/4/2013

1-P RE - OP A NA LYSIS


Requirements






Full length AP / Sagittal Xrays
Free standing position
Cervical Spine to Acetabulum

Spino-Pelvic Parameters



Global Alignment
Driver of the deformity




Lordosis versus Pelvic Incidence

Compensatory mechanism



Pelvic Tilt
Cervical …

2- P RE - OP P LA NNING



PI-LL < 10°

Objectives
 Correct regional / Focal
deformity
 Correct Global alignment
 Restore hip extension reserve


SVA < 5cm
PT < 20-25°

i.e. correct PT



Concept
 Direct correction of regional
spinal curvatures (LL and TK)
 Indirect correction of PT and SVA



Formula(s)
 Takes into account correlations
between parameters



PT = 1.14 + 0.71*(PI) – 0.52*(Max
LL) – 0.19*(Max TK)
SVA = -52.87 + 5.90*(PI) 5.13*(Max LL) - 4.45*(PT) –
2.09*(Max TK) + 0.566*(Age)
PI ~ LL

Complex
As easy as matching LL with PI

3- I NTRA -O P M ONITORING


Fluoro



During Surgery
Lordosis / Kyphosis





Long Cassettes







Focal
Regional

At the end of the case
Sagittal and Coronal plane
Regional curves
Compare with planning

Surgery vs. objectives



Several methods to reach objectives!
Tracking of adverse events

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8/4/2013

4- P OST - OP A NA LYSIS



Radiographic analysis



Spino-pelvic parameters below/above
‘ideal’ tresholds?
Compensatory mechanisms






Pelvis
Cervical spine
…

Root cause analysis




Post-op versus Planning
Post-op versus Intra-op
…..

R OOT

CA USE A NA LYSIS FINDINGS



Complex deformity can be analyzed by key parameters



Formulas permit prediction of alignment outcome



Pre operative planning optimizes chance of success



Gaps From theory to operative intervention and follow up







Quality of intra op images can limit verification
Reciprocal changes in non-fused portions of spine
Junctional issues
Other?

Next steps:



3

Improved patient specific models including reciprocal changes
Improved intra op feedback on alignment with pre op plan

C ONCLUSION

7

8/4/2013

C ONCLUSION


A new landscape


Substantial increase in ASD patients seeking treatment







Better understanding of ASD





Life expectancy, quality of life expectation

Increased rate of complex surgery (osteotomies)
Scrutiny on outcomes, complications, cost

Health impact, disability drivers
Ability to quantify, classify, treat: spino-pelvic parameters

How can we reduce realignment failure





Education is key
Patient evaluation
Surgical strategy: planning
Research translation into practice



Optimizing patient modeling, planning, technique
Defining acceptable trade-offs: risk vs. benefit

8

8/5/2013

Minimally Invasive Treatment of
Adult Deformity:
Research Update and Treatment
Gregory M. Mundis Jr., M.D.
San Diego Center for Spinal Disorders
La Jolla, CA
VuMedi Webinar, August 5, 2013

DISCLOSURES
• Consulting: NuVasive, K2M
• Royalties: NuVasive, K2M
• Research/Fellowship support: NuVasive,
Pioneer, OREF, ISSGF

MIS like a MAC?

1

8/5/2013

The Chasm

MIS

Geoffrey Moore, Crossing the Chasm, 1999

An Exploratory Effort
• Lit Search: 2021 articles with minimally
invasive spine surgery
• Predominantly single center retrospective
studies
• Little long term data
• No prospective Level 1 data to date

Literature search as of August 3, 2013

MIS The Answer?
• Perhaps a means
to an end
• Cannot abandon
the principles of
deformity
correction
• MIS is an approach
to reach the same
goal

2

8/5/2013

PLANNING, PLANNING, PLANNING
1. Measure all key parameters
2. Quantify the deformity (sagittal
and coronal)
3. Evaluate clinical options
– Fixation options
– Osteotomies
– Biologic issues

4. Execute plan…
– The value of intraoperative
scoliosis xrays

What are the limitations?
• Coronal
• Sagittal
• Long
segment/pelvic
fixation
• Osteotomies
• Fusion/Biology

Is There a Patient Profile That
Characterizes a Patient as a Candidate
for Minimally Invasive Surgery (MIS) to
Treat Adult Spinal Deformity (ASD)?
Robert K. Eastlack, MD; Gregory M. Mundis, Jr., MD; Michael Y. Wang, MD;
Praveen V. Mummaneni, MD; Juan S. Uribe, MD; David O. Okonkwo, MD, PhD;
Behrooz A. Akbarnia, MD; Neel Anand, MD; Adam S. Kanter, MD; Paul Park, MD;
Virginie Lafage, PhD; Christopher I. Shaffrey, MD; Richard G. Fessler, MD; Vedat
Deviren, MD; International Spine Study Group

IMAST 2013
Vancouver, British Columbia

3

8/5/2013

RESULTS
OPEN

MIS

n

118

46

p value =

Age (yrs)

60.6

64.1

0.022 (*)

Preop NSR Back

7.0

6.4

0.109

Preop NSR Leg

4.2

4.6

0.564

Preop ODI

41.4

42.7

0.624

Postop NSR Back

3.3

3.2

0.744

Postop NSR Leg

2.3

2.4

0.872

Postop ODI

25.1

23.7

0.653

Diff ODI

15.6

17.7

0.504

Results
OPEN

MIS

p value =

n

118

46

Thoracic Kyphosis

33

31.9

0.707

Cobb-lumbar (°)

42.8

32.4

0.0001 (*)

SVA (cm)

5.8

3.4

0.03 (*)

LL (°)

41.1

34.4

0.033 (*)

PI-LL mismatch (°)

13.6

21.4

0.014 (*)

PT (°)

23.6

27.7

0.024 (*)

* = p < 0.05

Conclusions
• Profile of ASD patients undergoing MIS
correction
– Less severe Cobb
– Less severe global sagittal malalignment
– Worse spinopelvic parameters (PT, PI-LL)
– MIS patients tend to be older
• Greater PI-LL mismatch in MIS patients (increased
lumbopelvic compensation in MIS patients?)
• Prospective, randomized trials necessary

• Other factors—BMI, EBL, revisions, complexity of
deformities, complications, etc.

4

8/5/2013

CORONAL

GM 2010

• 16 patients with
minimum 2 year follow
up
• All with VAS, ODI, and
SRS-22 improvement
• All with LIF and open
posterior

CORONAL CORRECTION LIF

5

8/5/2013

LIF Segmental Correction
Segmental Coronal
Correction

Segmental Lordosis
Restoration

Mundis et al. Spine, 2010

Acosta et. al
• 36 patients (66 levels)
• 7 with scoliosis
• 21.4  9.7 degrees
(p<0.05)
• VAS and ODI both
significantly improved

Acosta et. al.

6

8/5/2013

How does MIS compare to OPEN

• Propensity matched data by age, ODI,
SVA and major Cobb
• 31 Open; 31 Hybrid; 31 MIS
• NO difference in Cobb correction between
3 groups
IMAST Vancouver 2013, Podium Presentation

Is there a ceiling effect to MIS?
Wang et al. IMAST 2013
• 85 patients evaluated with 3 different
techniques
– Stand alone lateral, circumferencial MIS, Hybrid

• Stand alone 23 degrees
• Circumferencial: 34 degrees
• Hybrid: 50 degrees

Major Cobb

SVA

PI-LL

LL

OVERALL
(n=99)

3815

4.93.1

2311

3344

HYBRID (n=51)

4417

6.73.2

223

3248

SaMIS (n=8)

3331

4.24.8

2313.5

3238.5

cMIS (n=40)

3210

2.92.9

2116

3440

*ODI and VAS significantly improved in all 3
groups.

7

8/5/2013

SAGITTAL

AN EVOLVING MIS FRONTIER
• Historically poor showing
• WHY?
– Ignorance?
– Surgeon planning error?
– Implant limitations?
– Technique limitations?
– Education/training error?

INCOMPLETE CORRECTION

8

8/5/2013

Regional Improvement
• 23 pts: LL improved from 37  47.5
– Wang et al. 201

• 35 pts: LL improved 42  46
– Acosta et al.

• 8 pts: 40  47
– Tormenti et al.

• 16 pts: 31  44
– Akbarnia et al.

WHAT IS THE CORRECT QUESTION?
• Global Alignment?
• Regional Alignment?
• Segmental Alignment?
• What about Surgeon
Goals?

Comparison of Radiographic Results
after Minimally Invasive, Hybrid and
Open Surgery for Adult Spinal
Deformity: A multicenter Study of
184 patients
Raqeeb Haque, Gregory M. Mundis Jr., Yousef Ahmed,
Tarek Y. El Ahmadieh, Michael Wang, Praveen
Mummaneni, Juan Uribe, David Okonkwo, Robert
Eastlack, Neel Anand, Adam Kanter, Frank LaMarca,
Behrooz Akbarnia, Paul Park, Virginie Lafage, Jamie
Terran, Christopher Shaffrey, Eric Klineberg, Vedat
Deviren, Richard G. Fessler, ISSG

9

8/5/2013

METHODS
• Retrospective review of prospectively
collected databases
• Inclusion criteria:
– Age > 45yrs
– Lumbar Cobb > 20 degrees
– Minimum 1 year f/u

METHODS
• OPEN
– Open correction of scoliosis using posterior
technique for osteotomy and instrumentation

• MIS
– Combination of LLIF/TLIF/facet fusion with
percutaneous posterior instrumentation

• HYB
– Combination LLIF/TLIF with OPEN posterior
instrumentation

RESULTS

COBB ANGLE

MIS

HYB

OPEN

PRE-OP

32.1*

44.3

43.2

POST-OP

13.1*

17.7

20.4

∆

18.8

26.6*

22.8

50
40
30

MIS
HYB
OPEN

20
10
0
PRE OP

POST OP

CHANGE IN
DEGREES

10

8/5/2013

RESULTS

LORDOSIS

MIS

HYB

OPEN

PRE-OP

33.8

31.9

42.7

POST-OP

39.4

48.5

53.2

∆

5.8

17.4*

10.5

60
50
40
30

MIS
HYB
OPEN

20
10
0
PRE -OP

POST-OP

CHANGE
IN
DEGREES

RESULTS

PI-LL

MIS

HYB

OPEN

PRE-OP

21.6

22.0

12.3

POST-OP

16.1

2.1

2.0

∆

5.5

20.6*

10.2

25
20
15

MIS
HYB
OPEN

10
5
0
PRE OP

POST OP

CHANGE

RESULTS

SVA

MIS

HYB

OPEN

PRE-OP

29

65

47

POST-OP

30

31

31

∆

1*

34

36

70
60

50
40

MIS
HYB
OPEN

30
20
10
0
PRE OP

POST OP CHANGE IN
DEGREES

11

8/5/2013

RESULTS
MIS

HYB

OPEN

MEAN

SD

MEAN

SD

MEAN

SD

-3.2

2.1

-4.4

3.3

-3.7

3.0

∆

VAS-B

PRE to

VAS-L

-2.3

3.8

-2.0

3.9

-1.9

3.8

POST

ODI

-18.3

17.0

-16.4

13.9

-15.9

17.4

20
15
MIS
HYB
OPEN

10

5

NS

0
VAS-B

VAS-L

ODI

WHAT IF YOU NEED MORE?

•
•
•
•
•
•

17 consecutive pts
24 mo f/u
14 with previous spine surgery
71% treated for ASD
All had open posterior fusion
15/17 had a posterior release at
the level of the ACR

JSDT 2013

12

8/5/2013

• T1SPI:
– -6 to -2 (p<0.05)

• LL:
– 16  38 (ACR)  45
after PSFI

• PT:

• 8/17 complications
• 4 ACR related
– 2 neurologic
– 1 vascular (approach
surgeon removing
lateral plate)

– 34  24 (ACR)

• SRS-22, VAS
improved pre  post
(p<0.05)

72 YO F PJK S/P L1-S1

DOES IT COMPARE TO
PSO?

13

8/5/2013

ACR v PSO
• PROPENSITY MATCHED
– PI, LL, TK

• 17 patients in each group
• KEY FINDINGS:
– Groups comparable
– PSO with better T1SPI
correction (SVA)
– ACR with improved PT
correction but no PSO
– No difference in complication
rate
– ACR with less EBL

HOW ABOUT
COMPLICATIONS? PJK?

Does Minimally Invasive Posterior
Instrumentation (PPI) Prevent Proximal
Junctional Kyphosis (PJK) in Adult
Spinal Deformity (ASD) Surgery? A
Prospectively Acquired Propensity
Matched Cohort Analysis
Praveen Mummaneni, Michael Wang, Virginie Lafage, Kai-Ming Fu,
John Ziewacz, Jamie Terran, David Okonkwo, Juan Uribe, Neel Anand,
Richard Fessler, Adam Kanter, Frank LaMarca, Christopher Shaffrey,
Vedat Deviren, Gregory Mundis, ISSG

14

8/5/2013

RESULTS
• 31 patients propensity matched in each
group (CMIS, Hybrid)
• No significant difference in Age (65.6 vs
63.5, P=0.6)
• No significant difference in ASA score (1.8
vs 2.3 P=0.05)
• CMIS patients had lower ODI and VAS
back pain scores but similar leg pain
scores
• ODI: 39.1 vs 48.1 (P=0.045)
• VAS back: 6.1 vs 7.4 (P=0.013)
• VAS leg: 4.1 vs 4.6 ( P=0.53)

POST OP RESULTS
CMIS

HYB

T-test

Mean

SD

Mean

SD

P

31.3

11.1

45.3

19.0

.001

Thoracic Kyphosis

31.1

10.0

30.4

16.6

.849

Lumbar Lordosis

32.7

11.5

34.8

17.5

.593

Pelvic Tilt

25.9

11.8

27.4

11.1

.597

Pelvic Incidence

52.6

13.9

55.4

12.2

.389

Sagittal Vertical

29.2

41.7

53.3

61.4

.076

19.8

11.7

20.7

21.4

.845

Maximum Coronal
Cobb

Axis
PI-LL

PJK RESULTS
• Junctional segment analysis
revealed that CMIS had a smaller
change in PJA (1.3degrees vs 6
degrees, P=0.005)
• PJK developed in 19.4% of patients
in the hybrid group by 1 year
• No PJK was detected at 1 year in
the CMIS group.

15

8/5/2013

CONCLUSION
• CMIS and Hybrid approaches resulted in similar sagittal plane
radiographic and in HRQL results
• Radiographic PJK was detected in fewer patients in the CMIS group
at 1 year
• PPI may provide benefit in reducing PJK in adult deformity
procedures

Are Complications in Adult Spinal Deformity
(ASD) Surgery Related to Approach or Patient
Characteristics?
A Prospective Propensity Matched Cohort Analysis of
Minimally Invasive (MIS), Hybrid (HYB), and Open (OPEN)
Approaches
Juan S. Uribe, Praveen Mummaneni, Gregory Mundis, Virginie Lafage,
Behrooz Akbarnia, Paul Park, Robert Eastlack, Michael Wang, Neel Anand,
David Okonkwo, Adam Kanter, Frank La Marca, Vedat Deviren,
Richard Fessler, Chris Shaffrey, ISSG

OPERATIVE DATA

2500

100

2000

80

1500

60

1000

40

500

*

MIS
*

HYB

OPEN

20
0

0

% TRANSFUSION

EBL
p<0.003 *

16

8/5/2013

TOTAL COMPLICATIONS
70
60

P=0.004

50
40

MIS
HYB

30

OPEN

20

10
0
COMPLICATIONS %

COMPLICATIONS
Complication

MIS

HYB

OPEN

Total

Chi

With any

20%

46%

65%

45.2%

0.004

16.7%

27.6%

15.5%

0.020

Intraoperative
Postoperative

20%

36.7%

55.2%

38.1%

0.029

Major

12%

33.3%

44.8%

31%

0.032

Minor

8%

33.3%

41.4%

28.6%

0.020

3.6%

0.061

DVT

10%

PE

6.7%

3.4%

3.6%

0.414

3.3%

6.9%

6%

0.740

Neuro deficit

13.3%

3.4%

6%

0.090

Pneumonia

3.3%

1.2%

0.402

Wound dehiscence

3.3%

1.2%

0.402

Wound infection

3.3%

3.4%

2.4%

0.648

PJK

3.3%

3.4%

2.4%

0.648

Other major

6.7%

34.5%

14.3%

0.000

Implant failure

8%

CONCLUSION
• The surgical approach did matter when
evaluating for complications
• The MIS group had significantly fewer
complications (P=0.004) than did the HYB
group or the OPEN group
• If the goals of ASD surgery can be achieved,
consideration should be given to less invasive
techniques in order to reduce complications.

17

8/5/2013

SUMMARY
• MIS Spine surgery for deformity has it’s
limitations
– Surgeon technique
– Unknown fusion rates
– Severity of deformity

• The present and potential benefits warrant
further investigation
– The inventors and early adopters should be
encouraged to continue to drive the market to
see if they can cross the chasm

THANK YOU

18

7/30/2013

Health Economic Analysis of
Adult Spinal Deformity
Ian McCarthy, PhD
Institute for Health Care Research and Improvement
Baylor Health Care System
Baylor Scoliosis Center
Southern Methodist University
Department of Economics
VuMedi Webinar
August 2013

Role of Health Economics in Spine
Surgery
• Patterns and determinants of health care utilization and
production
• Impact and calculation of alternative reimbursement models
• Studies of market structure
• Health care labor markets
• Assessing the value of surgical treatment

Measuring Value
• Outcomes: Survival, readmissions, complications, healthrelated quality-of-life (HRQOL), quality-adjusted life-years
(QALYs)
• Costs: Indirect vs direct, sometimes difficult to measure
• Methods of analysis: Decision analysis, incremental costeffectiveness, comparative-effectiveness

1

7/30/2013

Quality-of-Life Outcomes
• Measuring quality of life
– Generic health profiles: SF-36, EQ-5D, Health Utilities Index
(HUI)
– Disease specific questionnaires: ODI, SRS-22
– Utility-based quality-of-life for estimation of quality-adjusted
life-years (QALYs): SF-6D, EQ-5D, HUI

QALYs
• QALYs are fundamentally grounded in economic theory and
expected utility theory in particular…cannot be estimated
from every HRQOL questionnaire
• Collapses HRQOL profiles over time into a single number
• Each year of life is weighted by the “quality” of that year, with
the quality factor derived by applying the relevant scoring
algorithm to the HRQOL responses
• Quality factor generally ranges from 0 to 1, with 1
representing perfect health and 0 representing death
– Values < 0 are also possible

• Two years of life at a quality of 0.5 yields 1 QALY

Estimating QALYs in ASD
• Clear selection issues into surgery, making comparisons
between operative and non-operative patients empirically
difficult
• Many patients have lived with condition for years and may not
present particularly poor baseline HRQOL
• Difficult to quantify the reduction in HRQOL that would have
happened without surgical intervention
– Relates to argument that surgery should be pursued earlier while
patient can appropriately recover. Need evidence-based justifications
for this approach (how much would HRQOL deteriorate without
surgery?)

2

7/30/2013

Defining Costs
Direct Costs: Resources consumed for the care of the patient.
Indirect Costs/Benefits: Time of patients or families consumed
or freed by the program in question.

Some confusion as the term “indirect costs” is used in
accounting to denote overhead. For economic evaluation of
health care programs, overhead is generally considered part
of the direct cost of care, although the allocation of overhead
to a specific surgery will tend to differ across hospitals.

Measuring Costs
• Hospital Costs
– Direct costs of patient care plus overhead and operational costs. Many
studies unclear as to whether overhead/operational costs are included
in calculation.
– High quality data but difficult to access for most authors.

• Payments/ Reimbursements
– Medicare formulas easy to replicate, but will differ dramatically from
managed care payments
– Very difficult or expensive to access managed care claims data

• Charges
– Poor measure of costs or reimbursements (monopoly money)
– Cost to charge ratios can be used for adjustments. Should be
performed at service level and not simply at hospital level.

Sources of Data
• Hospital Costs
– Accessed from hospital accounting records. Often unclear as to
whether costs include overhead or operational costs.
– In many states, hospital costs will exclude surgeon, anesthesiologist,
and internist fees (anyone who is not an employee of the hospital).
– Excludes follow-up costs (rehab, prescription drugs, outpatient visits)

• Payments/ Reimbursements
– Medicare inpatient reimbursement rates by DRG available from
MedPAR, and physician fees can be estimated from CPT codes
– Actual Medicare claims available from CMS
– Managed care claims potentially available from HCCI and MarketScan
Claims database (expensive)

• Charges
– Department level cost to charge adjustments can be estimated from
publically available HCUP data.

3

7/30/2013

Current Research: Costs of ASD
Aggregate Data from NIS (Healthcare Cost and Utilization Project)
• Inpatient stays in 2010
– 20,600 based on principal diagnosis
– 223,000 including secondary diagnoses

• Cost per inpatient stay
– $56,000 (3x more expensive than all other spine diagnoses)

• Annual costs
– $4.5 billion including secondary diagnoses
– Underestimate due to readmissions, rehab, prescription drugs, and
indirect costs

Current Research: Costs of ASD
Current Literature
• Average cost of $77,432 for revision surgery following proximal
junctional failure (Hart et al., 2008)
• Total hospital costs average $120,000 including subsequent
readmissions, with reimbursements averaging $200,000 (BSC
Data)
– $100,000 per-patient for primary surgery ($70,000 - $80,000 excluding
hospital overhead)
– $70,000 per-patient for readmissions

• Implant costs average $40,000 and account for 40% of total
hospital costs on average (BSC Data)
• No current studies of follow-up or indirect costs

Current Research: Costs of ASD
Why Does it Matter
• Measure of costs will dramatically change conclusions on CE of
surgery
• Hospital costs of $120,000 versus reimbursements of $200,000
(including readmissions)
– CE much worse when using actual reimbursements rather than hospital
costs

• Primary surgery costs of $100,000, increases to over $120,000
on average per patient after accounting for readmissions
– 20% reduction in CE

• Rehab and prescription drug costs likely to be significant, in
addition to indirect costs

4

7/30/2013

Cost-effectiveness
• Cost-effectiveness analysis is generally considered to be an
incremental analysis…need to compare one treatment to
another
• Most common measure of incremental cost-effectiveness:
Operative Costs – Non-operative Costs

ICER =

Operative QALYs – Non-operative QALYs

Cost-Effectiveness Analysis
• Statistical analysis of ICERs is difficult since denominator may
= 0 and sign of ratio may be uninformative
• Common presentation of results:
– ICER and 95% confidence interval
• Standard confidence interval formulae are not appropriate
• Confidence interval calculated based on alternative formula or bootstrap
technique

0

.2

.4

.6

.8

Probability Intervention is Cost-Effective

1

– Cost-effectiveness Acceptability Curves (CEAC): probability of ICER
falling below various dollar values

$80,000

$90,000
$100,000
$110,000
$120,000
Value of Health Effect (Willingness to Pay)

$130,000

Current Cost-Effectiveness
Worst Case
– Across ISSG centers, average baseline SF-6D ranges from 0.47 to 0.68.
Two-year follow-up ranges from 0.58 to 0.78
– Average gain of 0.16 QALYs after two-years, projected 0.4 QALYs after 5
years
– At $200,000 in reimbursements over 5-yr period, incremental CE is
$500,000 per QALY (excluding rehab and prescription drugs)

Best Case
– Predicted QALYs gained = 0.7 after 5 years
– At $200,000 in reimbursements over 5-yr period, incremental CE still
exceeds $280,000 per QALY (excluding rehab and prescription drugs)

Even with a high CE threshold of $140,000 (World Health
Organization recommendation of 3x per-capita GDP), ASD surgery
is not cost-effective without more formal empirical analysis and
extended or projected follow-up

5

7/30/2013

How to Improve CE Results?
1. Need to appropriately quantify hypothetical QALYs without surgery
2. Investigate cost drivers
–
–
–

Most costs incurred at index, but readmissions play important role both by
increasing costs and decreasing incremental QALYs
Implants are biggest single category of cost drivers…a 10% reduction in
implant costs is equivalent to a 13% reduction in readmissions
Potential conflicting incentives for cost reduction in states where managed
care remains a cost-plus reimbursement system

3. Prolonged evaluation period
–
–

Assess long-term durability of ASD surgery
Surgery begins to look cost-effective at 10+ years

4. Selection of surgical patients
–

Baseline HRQOL is perhaps the most relevant predictor of future costeffectiveness…many patients report similar post-operative HRQOL values, so
baseline values are biggest differentiating factor

Thank You

6



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