L5 S1 Controversies Syllabus

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1

Choosing Levels in Adult Scoliosis

Indications to Extend Fusion to the Sacrum and

Pelvis

Sigurd Berven, MD

Professor in Residence

UC San Francisco

Disclosures

•Research/Institutional Support:

–NIH, AO Spine, OREF, AOA

•Consultancies/Scientific Advisory:

–Medtronic, DePuy, Stryker, Globus

•Ownership/Stock/Options:

–Providence Medical, Simpirica

•Royalties: Medtronic

Challenges in Adult Scoliosis

Surgery

•Choosing Levels

•Junctional Complications

•When can we do less?

–When should we do more?

2

How High

How High

How Low

3

How High

How Low

When to go front and back

Surgical Strategies

•Characterized by significant variability

•Outcomes studies required for an Evidence-based approach

Overview

•The challenge of the lumbosacral junction:

–Strain on S1 screws

–Solid arthrodesis at L5-S1

•Biomechanics of the Pivot Point

•Techniques and Limitations

4

Hazards of the Junctions

•Thoracolumbar

•Lumbosacral

•Cervicothoracic

The Lumbosacral Junction

Two modes of failure:

1) Symptomatic degeneration below a

long fusion to L4 or L5

2) Nonunion or Malunion at L5-S1

Preoperative Assessment

•Localization of Pain on Physical Exam

•Advanced Imaging- MRI or CT

•Dynamic Imaging

•Provocative testing

–Facet Block

–Discography

5

The Case to Fuse to L5

•Better Function

•Less complications

•Good Survival of the L5-S1 motion segment

•Revision considerations

•Leaving options open for new technologies in the

future

•The loss of range of motion resulting from spinal fusion might lead to low back pain, trunk rigidity, and a negative

impact on quality of life. Nonetheless, these outcomes have not been conclusively demonstrated because lumbar

mobility and LIV have not been correlated with validated outcome instruments.

•METHODS:

•Forty-one patients (mean age, 27 y) with idiopathic scoliosis treated by spinal fusion (mean time since surgery, 135

mo) were included. Patients were assigned to 3 groups according to LIV level: group 1 (fusion to T12, L1, or L2)

14 patients; group 2 (fusion to L3) 13 patients, and group 3 (fusion to L4, L5, or S1) 14 patients. At midterm

follow-up, patients completed the Scoliosis Research Society (SRS)-22 Questionnaire and Quality of Life Profile

for Spine Deformities to evaluate perceived TF, and rated LBPi with a numerical scale. Lumbar mobility was

assessed using a dual digital inclinometer.

•RESULTS:

•Group 3 (fusion to L4, L5, or S1) showed statistically significant differences relative to the other groups, with less

lumbar mobility and poorer scores for the SRS subtotal (P = 0.003) and SRS pain scale (P = 0.01). Nevertheless,

LBPi and TF were similar in the 3 groups. TF correlated with SRS-22 subtotal (r = -0.38, P = 0.01) and pain scale

(r = -0.42, P = 0.007) scores, and with LBPi (r = 0.43, P = 0.005).

•CONCLUSIONS:

•LIV correlated moderately with lumbar mobility, health-related quality of life (SRS-22), and spinal pain (SRS-22

pain subscale), but not with intensity of pain in the lumbar area or perceived TF.

6

7

The slippery slope of extending

fusion to the sacrum

•Anterior column support

•Role of iliac fixation

Fusion to L5 vs. S1

8

L5 vs S1 Paradox

Thoracolumbar deformity arthrodesis to L5 in adults: the fate of the L5-

S1 disc.

- Edwards, Bridwell, et al. Spine 2003 Sep 15;28(18):2122-31.

•61% developed advanced disc degeneration at L5-S1

•Associated with loss of sagittal balance, need for revision surgery and lower

scores of SRS-24

•18% loss of fixation at L5

Higher incidence of complications in patients fused to S1

Edwards, Bridwell et al, SRS 2003

Failure of Fixation at L5

Purpose

Determine long-term radiographic and clinical

outcome of long (>T12) fusions to L5

The selection of L5 versus S1 in long fusions for adult

idiopathic scoliosis.

Swamy, Berven, Bradford.

Neurosurg Clin N Am 2007 Apr;18(2):281-8.

9

Survivorship Analysis

5 year: 75%

10 year: 70%

If include pts

considering

revision

5 year: 70%

10 year: 65%

Overall: 50% at

latest FU

The selection of L5 versus S1 in long fusions for adult idiopathic scoliosis.

Swamy, Berven, Bradford. Neurosurg Clin N Am 2007 Apr;18(2):281-8.

Conclusions

•Primary long fusions to L5 associated with

–25% revision rate at 5 years

–30% revision rate at 10 years

•Fusion to L5 is most reliable in patients with good

sagittal balance and bone quality

Indications to Extend Fusion to the Sacrum

•Symptomatic degenerative changes at L5-S1

–Spondylolisthesis at L5-S1

–Stenosis requiring decompression at L5-S1

•Significant sagittal plane realignment

•Osteoporosis

•Fixed obliquity of the L5-S1 motion segment

–Trunk translation

10

Sacral Fixation Considerations

•Sacrum is a poor fixation point due

to the large cancellous component

•Bicortical or tricortical fixation needed

•Sacrum exposed to large cantilever forces

•Fixation to the sacrum eliminates most

important sagittal compensatory mech.

•Fixation to the sacrum alters gait

Pedicle Fixation in

the Sacrum

•S1 pedicle screw is the

strongest fixation point

- unicortical fixation

- bicortical fixation

- tricortical fixation

•S2 pedicle screw

- short

- weak bone

0

1

2

3

4

5

6

7

8

9

020 40 60 80 100

Average Torque (in-lbs)

Percent Screw Length

Bicortical vs Tricortical Average Insertional Torque

Tricortical

Bicortical

Linear

(Tricortical)

Linear

(Bicortical)

Polly, Kuklo, et al

Limitations of Long Fusion to the Sacrum

•Cantilever forces for long segment constructs becomes

critical when sacral fusion extends to L3 or higher

–Shono, et al. Spine 1998

–Cunningham, et al. Spine, 2003

•Clinical correlation with a high incidence of symptomatic

pseudarthroses in long fusions to S1

•Kostuik 1983, 40% pseudarthrosis

•Boachie 1991, 41% pseudarthrosis

•Delvin 1991, 33% pseudarthrosis

•Lenke 2004, 23% pseudarthrosis

•Balderston 1986, 28% good result

11

Long fusions to the sacrum require anterior

column support +/- iliac crest extension

•Cantilever forces for long segment

constructs becomes critical when sacral fusion

extends to L3 or higher

–Anterior interbody decrease S1 screw strain 30-40 %

–S2 fixation decreases S1 screw strain by 15%

–Iliac fixation decreases S1 screw strain by 50 to 300 %

Limitations of Long Fusion to the Sacrum

•Cantilever forces for long segment constructs becomes

critical when sacral fusion extends to L3 or higher

–Shono, et al. Spine 1998

–Cunningham, et al. Spine, 2003

•Clinical correlation with a high incidence of symptomatic

pseudarthroses in long fusions to S1

•Kostuik 1983, 40% pseudarthrosis

•Boachie 1991, 41% pseudarthrosis

•Delvin 1991, 33% pseudarthrosis

•Lenke 2004, 23% pseudarthrosis

•Balderston 1986, 28% good result

McCord DH et al

Spine 1992

•66 bovine specimens/10 instrumentation

techniques

•Established pivot point at the lumbosacral

joint at the intersection of the middle

osteoligamentous column (sagittal plane) and

the lumbosacral intervertebral disc

(transverse plane)

12

Reducing Strain on Sacral Screws

in Long Fusions to the Sacrum

0

50

100

150

200

250

S1 Sublami nar

Wire S1 Hook S1 Pedicle

Screw S1 Screw with

S2 Hook Ch opin Block Iliosacral

Screw Iliac Screw with

S1 Screw Galveston wi th

S1 Screw Control

Moment (Nm)

MAXIMUM MOMENT AT FAILURE

S1 Fixation

S1/S2 Fixation

Sacro-Pelvic

Control

S2 SCREW

•“Biomechanical comparison of

lumbosacral fixation

Techniques in a calf spine

model”

Spine 2002, Lebwohl et al

•S2 screw extends fixation distal to

the pivot point thus extending lever

arm and providing additional

support

•However, the S2 screw does not

extend anterior to the pivot point

and thus not as good as iliac screw

fixation

PI

VOT

PIVOT

Long Fusion To The Sacrum in Adult Spinal

Deformity: Luque Galveston vs. Iliac Screws

vs. Sacral Screws

Emami et al:Spine 2003

UCSF Spinal Disorders Service

13

Iliac Bolt Fixation

•Bolt or screw is passed

into the ilium at the PSIS

•Bolt or screw is affixed

directly to the spine construct

•Effective in high demand

construct

•Failure rate half of traditional

Galveston

How Many Iliac Screws?

14

Study Aims and Design

Goals

Pelvic versus Sacral + ALIF

Unilateral iliac versus bilateral iliac

Methods

Seven cadavers instrumented up to L1

Multi-axial bending with pure moment

S1 screws modified with strain gauges for

pullout force

L1-S1, uni-iliac, bi-iliac… with and without

ALIF at L5/S1

Multi-axial bending

0%

10%

20%

30%

40%

50%

L5-S1 –Percent of Intact (%)

FLEXION/EXTENSION

*

** *

* L1-S1

** uni-iliac

0%

20%

40%

60%

80%

100%

120%

140%

LATERAL

BENDING

*

*

** **

** L1-S1

** ni-iliac

0%

10%

20%

30%

40%

50%

60%

70%

AXIAL ROTATION

**

**

* L1-S1

** uni-iliac

*

One vs Two Iliac Screws

•100 patients with long fusions from thoracic spine

to the sacrum

–53patients with 2 iliac screws

–47 patients with 1 iliac screws

15

Limitations of Iliac Fixation

•Higher incidence of perioperative complications

–Wound infection

•Abdul-Jabbar A, et al.

•Higher incidence of need for revision surgery

–Screw removal

•Emami A, et al.

Evidence-based approach to the use

of Iliac Fixation

•Extension of fixation to ilium in:

–Compromised anterior column support at L5-S1

•TLIF at L5-S1

–Revision fixation to the sacrum in a long construct

•Above L3

–Compromised sacral fixation

–Incomplete correction of sagittal and coronal balance

–Pelvic obliquity/Long thoracolumbar (c-shaped) deformity corrected

with cantilever maneuver

–Ankylosing Spondylitis

Conclusions

•Fixation at the lumbosacral junction is challenging and

important for stable reconstructions in deformity

•High strain on the sacral screws may lead to screw

loosening and nonunion

•Pelvic fixation reduces strain on the sacral screws

•Role of biologics and new technologies in limiting need

for iliac fixation requires further investigation

16

UCSF Center for Outcomes Research

1

Spino-Pelvic Parameters:

How Do They Affect My

Decision to Extend a Fusion to

the Sacrum/Pelvis

Han Jo Kim MD

Frank J. Schwab, MD

Bassel G. Diebo, MD

Virginie Lafage, PhD

Hospital for Special Surgery

New York, NY

Disclosures

•Consultant

–K2M, Biomet, Medtronic

•Speaker Bureau (not present, within last 36 months)

–Depuy, Stryker

•Board Membership

–ASJ, HSS Journal

SPINOPELVIC PARAMETERS

2

Setting Surgical Goals

Regional

Loss of lordosis

Versus PI

Global

SVA

Compensatory

Pelvic tilt

PI-LL < 10°SVA < 5cm PT < 20-25°

Literature Review

•34 consecutive adult deformity patients fused from the

thoracic spine to L5

•Subsequent L5-S1 DDD developed in 66% of patients

after long adult fusions to L5

Literature Review

•High percentage of patients subsequently degenerated the L5-

S1 disc

•With degeneration of the L5-S1 disc, sagittal balance was

frequently lost

•Prevalence of breakdown of the L5-S1 disc much greater in

the “long”fusions (T4-L5) vs. the “short”fusions (T10-L5)

3

Literature Review

Kim YJ, Bridwell KH, Lenke LG, Cho K, Edwards II C,

Rinella AS: Pseudarthrosis in adult spinal deformity following

multisegmental instrumentation and arthrodesis. J Bone Joint

Surg 2006;88(4):721-728

•A clinical and radiographic assessment of 232 adults

•Factors found to be significantly associated were preop

thoracolumbar kyphosis of >20°, age of >55 years,

arthrodesis to S1 compared to L5

•Patients with a pseudarthrosis had lower total outcome scores

on SRS questionnaire

•Prevalence of pseudarthrosis following long arthrodesis was

17%. Close to 30% for fusions to sacrum.

Literature Review

Islam NC, Wood KB, Transfeldt EE, Winter RB,

Denis F, Lonstein JE, Ogilvie JW. Extension of

fusions to the pelvis in idiopathic scoliosis. Spine

2001;26(2):166-173.

•41 patients (40 female; 1 male)

•39 of 41 had combined anteroposterior fusion extension

•Pseudarthrosis rate was 37% (15/41)

•With sacral fixation only, the rate was 53% (8/15), with

iliac fixation only 42% (3/7) and with both iliac and

sacral fixation 21% (4/19; p<0.05)

Enami A, Deviren V, Berven S, Smith JA, Hu SS,

Bradford DS. Outcome and complica-tions of long

fusions to the sacrum in adult spinal deformity. Spine

2002;27:776-686.

Literature Review

•54 consecutive patients who underwent elective combined anterior

and posterior surgical reconstruction for acute spine deformity were

studied

•Attention to sagittal balance is critical

•Luque-Galveston fixation technique has an unacceptably high rate

of pseudarthrosis. Currently, the authors are using bicortical and

triangulated sacral screws with anterior interbody support

•They recommend using iliac fixation, although there is a higher rate

of painful implants, requiring removal

4

McCord DH, Cunningham BW, Shono Y,

Myers JJ, McAfee PC. Biomechanical analysis

of lumbosacral fixation. Spine

1992;17(8S):S235-243

Long fixation points in the ilium that extend

anterior to the axis of rotation of L5-S1 provide

the most stable fixation of the lumbosacral

joint.

Literature Review

Literature Review

Cunningham BW, Lewis SJ, Long J, Dmitriev

AE, Linville DA, Bridwell KH. Biomechanical

evaluation of lumbosacral reconstruction

techniques for spondylo-listhesis: An in vitro

porcine model. Spine 2002;27(21):2321-2327

In a spondylolisthesis model, both the iliac screws and

the interbody cages at the lumbo-sacral junction

protected the S1 screws, but the iliac screws were far

more valuable.

•Age

–Bone quality

–Degenerative changes in disc, foramen, canal

•Deformity

–Large SVA

–Large Coronal Decompensation

–Large Curve Magnitude

–Rigid vs. Flexible Deformity

–Presence of L5/S1 Spondylolisthesis

–Laminectomy Defects at L5/S1

Factors that Dictate my Decision to Fuse

to Sacrum/Ilium

5

Factors that Dictate my Decision to Fuse

to Sacrum/Ilium

•Age

–Bone quality

–Degenerative changes in disc, foramen, canal

•Deformity

–Large SVA

–Large Coronal Decompensation

–Large Curve Magnitude

–Rigid vs. Flexible Deformity

–Presence of L5/S1 Spondylolisthesis

–Laminectomy Defects at L5/S1

•Spino-Pelvic Parameters

–High PT

–High PI

High PT

•PT will be very difficult to correct without

fusion to S1 and Iliac Fixation in Adult

Spinal Deformity

High PI

• “Guillotine Effect” of Fusion to L5 on

L5/S1 Disc Space

–High shear stresses

6

Substantial sagittal imbalance, back pain, inability to

ambulate

PT 36

LL 20

PI 55

SVA 20cm

Cantilever to “Dial In” Pelvic

Anteversion

PT 36

LL 20

PI 55

SVA 20 cm

PT 8

LL 55

PI 55

SVA 1cm

Case

•79M with bilateral leg and back pain

–10% back, 90% leg pain

•50% Left, 50% Right

–Exacerbated by standing/walking

–Improved with sitting, lying down (some

positions)

–No bowel/bladder symptoms

–Subjective weakness/numbness when

ambulating

–Failed PT/Injections

7

Exam

•Marked Positive Sagittal Balance

•Can only stand for a short period of time

•Static Motor Exam intact

•Sensory exam normal

PI 50

PT 26

LL 9

TK 27

CL 4

SVA 17

8

L1/2 L2/3 L3/4 L4/5

Questions

•Osteotomy? Can you do PCOs? Or will this

need a PSO?

–If PSO, what level?

–If PCO, what level(s)?

•Is an Interbody necessary?

–Lateral? Transforaminal? Anterior?

•Choice for UIV? Lower or Upper Thoracic?

•Iliac Fixation?

•Will you need Biologics?

9

PSF T11-Ilium, PCO L1-L5, TLIF L5/S1

PI 50

PT 8

LL 50

TK 40

SVA -5mm

2 yrs post-op 2 yrs post-op

Do We Always Have To

Go To The Sacrum? Are

There Select

Circumstances Where

We’d Be Better Off

Stopping At L5?

Case following Courtesy of Dr. Keith H. Bridwell MD

10-7-05

69+11

10-7-05

69+11

56°

Frail Almost 70-Year-Old Female. Bilateral Leg

Pain And Weakness, Left Greater Than Right.

Good Sagittal Parameters!

10

Large Calcified Disc Herniation at T11-T12 on the Left Side

Stenosis at L3-L4

10-7-05

69+11

Preop Postop Preop Postop

10-7-05

69+11

56°

9-14-09

73+10

3+9 yr po

9-14-09

73+10

3+9 yr po

4 Year Follow-up

11

Oswestry Scores

0

25

50

75

100

Preop Ultimate Postop

46

14

100 100

Score Potential

Balance Risks/Benefits

•Large PI-LL mismatch

•Large PT

•Large PI (natural anatomy)

Balance Risks/Benefits

•Large PI-LL mismatch

•Large PT

•Large PI (natural anatomy)

•Need fusions to Sacrum/Ilium

•Pseudo Risk

9/8/2015

1

L5-S1 Fusion options

Approach, Interbody

support, & Graft

Options

Jason W. Savage, MD

Cleveland Clinic

Center for Spine Health

9/8/2015

Disclosures

•Consultant: Stryker Spine

•Editorial Board: JSDT

•Off-label use of BMP

outline

•Approach

–Anterior

–Posterior

•Interbody Support

–ALIF/PLIF/TLIF/OLIF

–Advantages/Disadvantages

–Is it necessary ???

•Graft Options

–Bone vs. PEEK vs. Metal

–BMP

9/8/2015

2

Goals of surgery

•Restore regional lordosis

• “Fix”the fractional curve

•Achieve a solid fusion

Up to 25% pseudarthrosis

rate at L5-S1

Anterior approach

•Advantages

–Access to disc space

–Large structural graft

–Lordosis

•Disadvantages

–Unfamiliar and

separate approach

–Complications

Posterior approach

•Advantages

–Provides interbody

support

–Single

approach/procedure

•Disadvantages

–Inferior disc “prep”

–Graft extrusion

–Nerve root irritation

–Fusion ???

9/8/2015

3

Anterior vs. posterior

J Neurosurg Spine 2007;7:379-386.

-3

-2

-1

0

1

2

3

4

5

6

7

1 2

ALIF

TLIF

•Retrospective

•32 ALIF vs. 25 TLIF

•Foraminal Height

•18.5% vs. -0.4% (p<0.01)

•Segmental Lordosis

•8.3 vs. -0.1°(p<0.01)

•Regional Lordosis

•6.2 °vs. -2.1°(p<0.01)

Lumbar Lordosis

Anterior vs. posterior

•Retrospective

•ALIF vs. TLIF in ASD

•42 pts in each group

•Segmental lordosis

–6.9°vs. -2.6°(p<0.0001)

•Regional lordosis

–11.5°vs. 7.9°(p=0.29)

Spine 2013;38:E755-E762.

Spine 2013;38:E755-E762.

NO DIFFERENCE IN RATE OF PSEUDARTHROSIS

9/8/2015

4

Br J Neurosurg 2015;Early Online:1-7.

•Systematic Review (12

Retrospective Studies)

–609 ALIFs, 631 TLIFs

•Fusion Rates

–88.6% vs. 91.9% (p=0.23)

•Disc height (2.71mm)

•Segmental lordosis (2.35deg)

•Lumbar lordosis (6.33deg)

Interbody graft OPTIONS

•Provide structural support

–Function is primarily mechanical

•Require “other”bone graft

substitutes to achieve bony

fusion

•Implant material is important

–Limit subsidence and stress

shielding

–Bone integration

Interbody graft OPTIONS

•Femoral Ring Allograft

– “Biological Cages”

–Natural elasticity

–Potential for incorporation

•PEEK

–Elasticity less than cortical bone

–No potential for incorporation

•Titanium

–Elasticity is much greater than

bone

–Radiopaque

9/8/2015

5

J Spinal Disord Tech 2014;27:327-335.

•Retrospective review

•ALIF with PEEK (N=27) vs. RFA (N=14)

at L5-S1

•X-ray evaluation

•Fusion Rates

–94.9% vs. 84.2% (p<0.05)

•Improved foraminal height and

segmental lordosis with PEEK

Eur Spine J 2014;23:2150-2155.

•Retrospective

•Single level TLIF with local autograft

•Titanium (N=23) vs. PEEK (N=25)

•Fusion Rates

–100% vs. 75% at 2 years (p=0.016)

•Vertebral osteolysis was seen in

60% of PEEK non-unions

•Expandable Cages

• “Surface Enhanced”

•Silicone Nitrate

•Tantalum

•3D Printing

•Nanotechnology

Interbody graft OPTIONS

9/8/2015

6

MSC

DBM BMP

Ceramics

Allograft Autograft

Efficacy Safety

RegulatoryCost

The world of biologics

Courtesy of Wellington K. Hsu, MD

# Studies # Patients # Fused

Rate

(%)

ICBG 23 1389 1103 79%

Local Autograft 8 714 637 89%

Allograft alone 4 269 141 52%

BMA 2 40 34 85%

BMP - 2 3 213 201 94%

Ceramics 16 697 603 87%

DBM13192 171 89%

PRP 4 209 154 74%

•Retrospective Study

•ALIF in ASD

–ICBG (N=32) vs. BMP (N=23)

•Fusion Rates

–71.9% vs. 95.7% (p=0.057)

•Follow-up

–4.9 vs. 2.7 years

Spine 2009;34:2205-2212.

9/8/2015

7

•Retrospective Case Series

•L5-S1 Interbody fusion vs. PLF

–IF (N=35) vs. PLF (N=26)

•Average BMP

–4.1mg in IF vs. 3.2mg in PLF

•Fusion Rates

–97% vs. 96% (p=1.0)

Spine 2015;11:E634-E639.

•ALIF

–Sagittal plane deformity (mostly from

L4-L5 and/or L5-S1)

–Adjacent segment pathology below a

previous fusion (i.e. AIS)

•TLIF

–De novo scoliosis with “tall”disc or

spondy

–Fractional curve

•PLF alone

–De novo scoliosis with collapsed disc

My algorithm at L5-S1

Case example

Courtesy of Doug Orr, MD

9/8/2015

8

Case example

•Historically high rate of

pseudarthrosis at L5-S1

•Iliac Fixation, 360°, and

Biologics have improved

fusion rates

•ALIF improves disc height,

segmental lordosis, and LL

better than TLIF

•Likely no difference in

fusion

•Still a lot of questions ???

Conclusions

Thank you

1

Department of Orthopedic Surgery

Johns Hopkins University

Sacroplevic Fixation

Options, Techniques and

Complications

Khaled M. Kebaish, M.D., FRCSC

Professor of Orthopedic & Neurosurgery

DISCLOSURE

Depuy Spine Consultant, Royalty

K2M Consultant

Orthofix Consultant

WHY PELVIC FIXATION?

S1 Pedicles capacious & short

Sacrum bone is osteopenic

Failure rate of S1 Screws

Up to 44%

Inadequate as the only means

of fixation in long fusion

Camp et al, Spine 1990

2

INDICATIONS FOR

PELVIC FIXATION

Expected significant biomechanical

stresses

Long fusions to the sacrum

Definition: > 4 levels

Osteoporosis

Sacral Fracture

3

Sacro-Pelvic Fixation Options

Casting and bracing

Sacral Sublaminar

devices

Wires

Cables

Hooks

Sacral pedicle screws

S1 pedicle screws

S2 Pedicle screws

S1 Alar screws

S1 and Alar screw

blocks

Dunn-McCarthy S-

Rod

Jackson intra-sacral

rod

Kostuik sacral bar

Galveston technique

Iliac Screws

Sacral Alar Iliac

screws (S2AI)

LUMBO-SACRAL PIVOT POINT

“Axis about which the lumbo-

sacral region rotates”

Middle of osteo-ligamentous

column at L5-S1

Implants ventral to this point

provide an effective moment

arm to resist flexion &

improve fixation strength

McCord et al, Spine, 1992.

LUMBO-SACRAL PIVOT POINT

McCord et al, Spine, 1992.

4

GALVESTON TECHNIQUE

Most commonly used in NM Spinal

deformities

Inexpensive

Difficult to get the correct angle

Loss of correction

Windshield wiper effect

Broom MJ, et al, JBJS (A), 1989.

Gau Y, et al, J Spinal Disord, 1991.

Moseley C, et al, Orthop Trans, 1986.

Jackson Technique

S1 pedicle screws

Rod placed in S1 screw and

into sacral ala

Not crossing the SI joint

Technically difficult

Biomechanically weaker

than iliac fixation

Jackson RP, et al, Spine, 1993.

Lebwohl NH, Spine, 2002.

Iliac Screws

Commonly used

Fixation with screws

Implants easier to place

Reduction in LS motion

More Protective of S1

than IB cages

Cunningham BW, et al, Spine, 2002.

5

67 patients ( 81 initial Cohort)

5 years Follow-up

Iliac screws removed in 23 pts

7 broken screws

Screws halos in 29 pts

No SI joint arthritis

Woojin et Al. paper 46,

IMAST 2011

67 of 190 patients

Iliac screws

Minimum 2 ys follow-up

34.3 % failure

11.9 Major failure

S2 Alar –Iliac S2AI

“SAI”

6

Surgical Technique

How it all started?

Surgical Technique

How it all started?

Surgical Technique

How it all started?

7

Surgical Technique

How it all started?

Surgical Technique S2AI

Starting point:

Midway between S1 & S2 foramina

2.5 mm drill from pelvic set

Trajectory: 45oto floor

20-30ocaudal

“Varies w. pelvic obliquity & Sacral tilt”

Aim for the AIIS

Confirm bony end point with a

probe

8

Surgical Technique S2AI

Surgical Technique S2AI

9

Surgical Technique S2AI

Screw path just above sciatic notch

Fluoroscopy is helpful

Iliac oblique, Tear drop

10

Surgical Technique S2AI

Screw path just above sciatic notch

Fluoroscopy is helpful

Iliac oblique, Tear drop

Diameter 8-10 mm

Length 80-100

Biomechanics

Biomechanical properties equivalent

to Iliac screws

Stress-strain & load to failure

0

50

100

150

200

S1+S2 Screw S1+S2 Portal S1+Iliac Screw

11

Department of Orthopaedic Surgery

Johns Hopkins University

Outcomes and Complications of Sacro-Pelvic Fixation Using

S2 Alar-Iliac (S2AI) Fixation in Adult Deformity patients:

A prospective Study with 2-Year Follow-Up

Khaled Kebaish, MD

Mostafa El Dafrawy,,M.D

Hamid Hassanzadeh, M.D

Philip Neubauer, M.D

Roosevelt Offoha, BS

Eric Tan, M.D

Paul Sponseller, MD

RESULTS

146 patients were included

2 year clinical & radiographic F/U

2 patient were lost to follow up

Average age: 59 ys (21-80)

35% of patients had > one co-

morbidity

S2AI Fixation specific complications

Screw Breakage

8 (5 pts)

Screw

Misplacement 2

Minimal Screw

loosening

(<2mm) 13 patients

16 screws (6%)

Reoperation

4

12

Sacropelvic Fixation Using the

S2 Alar-Iliac (S2AI) Screw in

Adult Deformity Surgery:

A Prospective Study with

Minimum 5-Year Follow-Up

Sophia A. Strike, MD; Hamid Hassanzadeh, MD;

Floreana Naef, MD; John Carrino, MD;

Paul D. Sponseller, MD; Richard Skolasky, ScD;

Khaled M. Kebaish, MD

S2AI FIXATION

COMPLICATIONS

109 S2AI screws placed

Six broken screws (four patients)

> 2 mm lucency: 20 screws

No pseudoarthrosis at L5-S1

No SI joint degeneration

Effect on the SI Joint

There was no evidence of

SI joint fusion

No significant change in

joint space

No significant SI joint area

pain

Corlett EN, Bishop RP. Ergonomics 1976

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Concerns of Fusion Across SI Joint

Anatomic studies

Minimal motion in

pediatric cadavers

No motion in adult

cadavers

75% auto fused in

adults over 50 years

Asher MA, et al, CORR, 1986.

Kostuik JP, et al, CORR, 1986.

White AA, et al, Surgery of Musculoskeletal System, 1990.

Adult Scoliosis

71 YO M

Retired Physician

Severe Back Pain

and Rt Buttock

Used to be very

active now

Limited by his

symptoms

No Prior Rx

14

62 y.o. Female

Degenerative on Idiopathic

Spondylolithesis

15

Spondylolithesis

Spondylolithesis

16

Spondylolithesis

Sacral Fracture

17

Bone Graft Harvest!

18

Bone Graft Harvest!

DISCUSSION

Implant fractures were only seen with

smaller diameter screws (7mm)

Recommend using Larger screws (>8mm)

Loosening > 2mm very rare

Reoperation and removal are infrequent

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S2AI Technique

Relatively easy and safe

Minimal offset from the axis of

spine

Less prominent

One rod no connectors

Better control of the pelvis

S2AI Technique

Relatively easy and safe

Minimal offset from the axis of

spine

Less prominent

One rod no connectors

Better control of the pelvis

EASIER TO PERFORM

RECONSTRUCTIVE PROCEDURES AT

THE LS JUNCTION

Conclusion

Many techniques for PELVIC FIXATION

High Rate of implant related problems

S2 Alar Iliac (SAI) technique easy & safe

Lower Complications

Effective in distal LS corrective

procedures

No effect on the SI joint at 5 ys!

Can be done through an MIS approach

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THANK YOU