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Pedicle Subtraction Osteotomies :

A Useful Tool in Revision of Adult Spinal

Deformities

Munish C. Gupta, MD

Professor of Orthopedic surgery

Chief of Spine Service

University of California, Davis

Sacramento, California

Las Vegas

2013

67 yo female Multiple Surgeries

Severe Low back

pain

Decompensated

coronally and

sagittaly

Normal neurology

Smoker

Morphine pump

Surgical Plan ?

Anterior

release/resectio

n and Posterior

Fusion

Pedicle

subtraction

osteotomy

Vertebral

Column

Resection

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PSO

Pedicle Subtraction Osteotomies

First Described by

Leong then Thomasen

Charles Heinig used it

with Decancellation of

the vertebral Body

Resection

– Spinous process

– Lamina

– Facet joint

– Pedicle

CORR vol 194 April 1985

Pedicle Subtraction Osteotomy

Indications

Technique

Pitfalls

Complications

Difference between Primary

and Revision

Indications for Pedicle

Subtraction Osteotomies

Heinig who uses this for an approach

Sagittal plane deformity

Minimal coronal plane deformity

Multiple surgeries anterior or posterior

Grade III - Partial body resection

Most suited when >20° segmental correction needed

Appropriate even through fusion

All levels of spine possible Preferable below conus

Frank Schwab, MD

Virginie Lafage, PhD

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Positioning

Table that can bend

Abdomen free

Pad all the pressure points

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Decompression

Midline laminectomy extending above and

below

Pedicle to pedicle posterior element bony

resection

Follow the nerve roots out

Osteotomy

Hollow out the body with curettes

Dissect outside the body

Ronguer the the body

Use the table for closing the osteotomy

Use temporary rods to control the

correction

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2001 2002

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2013 Pathologic Behaviour

Increasing

pelvic tilt with

increasing

kyphosis

Sagittal plane interpretation and

management deformity

PierreRoussouly • Colin Nnadi

Aims of Sagittal Plane

Realignment

Gravity line atleast through

femoral heads

Lumbar lordosis and Pelvic

incidence within 10 degrees

Pevic tilt less than 25

T1 to L5 anterior and posterior spinal fusion

64 yo male

Severe back

pain

Hard to stand

and walk

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Fused in flat back position

Flat lumbar spine

Discectomy at

L5-S1

Disc

degeneration L5-

S1

Flatback

Anterior fusion

with femoral ring

allograft

Pedicle

subtraction

osteotomy

Extension of

instrumentation

to the pelvis

Anterior L5-S1 fusion and

Pedicle subtraction osteotomy

Sagittal Decompensation

Inadequate lordosis

L5 fracture

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Pedicle Subtraction Osteotomy

Anterior L5-S1 fusion

with femoral ring allograft

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Anterior

L5-S1 and

L4-5

femoral ring

PSO L3

Correction of Lumbar Lordosis

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Pedicle Subtraction Osteotomies

Blood loss

Neurologic Compromise

Nonunion

Proximal Junctional Failure

Proximal Junctional Kyphosis in Adult Spinal Deformity After

Segmental Posterior Spinal Instrumentation and Fusion

Minimum Five-Year Follow-up

PJK at 7.8 years postop was 39%

Progressed significantly within 8-weeks postop

Risk factors

– Older age at surgery >55 years

– Combined anterior and posterior approach

The SRS outcome not adversely affected

– except the self-image domain when PJK was >20°

Kim et al. Spine • Volume 33 • Number 20 • 2008

PSO Personal Series

29 patients Checked in 2010

All revisions

Previous fusions and instrumentation

Angle of PSO correction

– Ave 39 Deg( 25-54 deg)

C7 Plumbline

– Improved from +14.4 to +6.0 cm

PSO Personal Series Infection 2 – Multiple previous surgeries and usually have

a previous infection

Pseudoarthrosis 1 – Removal of instrumentation for infection

Neurologic Deficits 6.8% permanent

weakness

– I Cauda equina resolved

– 3 Temporary Hip Flexor weakness

– 4 Lumbar radicular symptoms

– 2 patients with foot dorsiflexion weakness 4/5

not requiring AFO

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Multiple previous surgeries

Junctional

kyphosis

Pseudoarthrosis

at multiple levels

Another one

Kyphosis WR Patient

69 Years old

Worsening Back Pain

Decompensation getting worse

Unable to stand and walk

because of pain in back

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Choices

1----3 stage – Removal of cage

– posterior osteotomies and fusion T4 to the pelvis

– anterior strut or cage

2-----2 stage – Posterior osteotomies and fusion T4 to the pelvis

– Anterior removal of cage replaced with strut or cage

3-----1 stage – Posterior osteotomies and fusion T4 to pelvis

4-----None of the above

Introp Myelographic block

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Pedicle Subtraction Neurologic Complications of Lumbar Pedicle

Subtraction Osteotomy

A 10-Year Assessment

11.1% (12 of 108 pts)

Permanent deficit of 2.8% (3 of 108 pts).

Always unilateral and distal to the level of

the osteotomy.

Combination of subluxation, residual

dorsal impingement, and dural buckling.

Neuromonitoring did not detect any of the

deficits.

Buchowski et al. SPINE Volume 32, Number 20, pp 2245–2252

Neurologic Complications of Lumbar Pedicle

Subtraction Osteotomy

A 10-Year Assessment

Buchowski et al SPINE Volume 32, Number 20, pp 2245–2252

Role of Pelvic Incidence, Thoracic Kyphosis, and

Patient Factors on Sagittal Plane Correction

Following Pedicle Subtraction Osteotomy

1. LL should be 10° greater than PI.

2. LL should be 15° greater than TK.

3. The sum of PI, LL, and TK should be <or= 45°.

Rose et al. SPINE Volume 34, Number 8, pp 785–791

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Role of Pelvic Incidence, Thoracic Kyphosis, and

Patient Factors on Sagittal Plane Correction

Following Pedicle Subtraction Osteotomy

PSO success at 2 years(91% sensitivity )

– PI + LL +TK <or= 45°

Lose sagittal balance correction

– gradual progressive kyphosis of segments

cephalad to the fusion

– occasionally due to collapse of the L5–S1

disc.

Rose et al. SPINE Volume 34, Number 8, pp 785–791

Pedicle Subtraction Osteotomy (PSO) in the

Revision versus Primary Adult Spinal

Deformity (ASD) Patient: Is there a difference in

correction and complications?

Gupta. Terran, Mundis, Smith, Shaffrey, Han,

Boachie-Adjei, Lafage, Bess, Hostin, Burton,

Ames, Kebaish, Klineberg.

International Spine Study Group

Materials and Methods

A retrospective review of a large multi-center

database of 353 adult spinal deformity

– The inclusion criteria

age >18 ,either SVA > 5cm, pelvic tilt > 25 deg,

scoliosis >20 deg ,thoracic kyphosis > 60 deg

Study Population

– PSO in the lumbar spine

– complete peri-operative complications data

– one year follow-up radiographic and clinical data

Results

260 pts out of 353 pts met the inclusion

criteria.

37 patients underwent Primary PSO

223 patients underwent Revision PSO

Minimum 1 yr Follow –up

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Demographic Results

Primary Revision t-test

Mean SD Mean SD p

Age (years) 60.1 13.6 58.9 10.9 0.549

BMI

(kg/m2)

26.1 7.2 27.9 6.8 0.184

OR time

(mn) 404 127 455 145

0.114 Blood Loss

(ml) 2654 2742 2696 1945

0.924 # levels

fused

10.5 4.0 10.7 3.9 0.802

The OR time and blood loss was not statistically different

Primary PSO

Pre-op Post Δ pre to post t-test

Mean SD Mean SD Mean SD p

Thoracic

Kyphosis T2-

T12

30.1 22.0 47.6 14.9 17.4 16.6 .0000

Thoracic

Kyphosis T4-

T12

28.8 21.5 41.5 13.5 12.7 19.4 .0003

Lumbar

Lordosis L1-S1 -24.0 25.1 -53.3 11.9 -29.3 26.0 .0000

Sagittal Vertical

Axis 127.9 78.4 30.8 52.9 97.2 80.1 .0000

T1 Spino-Pelvic

Inclination 3.6 7.0 -4.3 4.8 8.0 7.0 .0000

Pelvic Tilt 31.2 12.2 23.2 9.6 7.9 10.5 .0001

PI minus LL 30.8 25.8 1.9 12.4 28.9 25.8 .0000

Statistical improvement in sagittal parameters

Revision PSO

Pre-op Post Δ pre to post t-test

Mean SD Mean SD Mean SD p

Thoracic

Kyphosis T2-T12 30.2 19.1 44.6 17.3 14.4 14.6 .0000 Thoracic

Kyphosis T4-T12 27.2 17.7 37.4 16.8 10.1 14.7 .0000 Lumbar Lordosis

L1-S1 -23.2 19.1 -52.6 14.7 -29.3 16.7 .0000 Sagittal Vertical

Axis 141.8 76.5 40.9 59.8 100.9 74.2 .0000 T1 Spino-Pelvic

Inclination 4.4 7.2 -3.4 5.5 7.8 7.0 .0000 Pelvic Tilt

32.3 10.6 24.5 11.0 7.8 8.6 .0000 PI minus LL

36.3 18.4 7.0 16.8 29.2 16.6 .0000

Statistical improvement in sagittal parameters

Intra-operative Complications

Complication ALL Primary Revision

Intra-op

Bleeding > 4L 20.3% 27.6% 19.1%

Intra-op Cardiac

Arrest

0.5% 0.0% 0.5%

Intra-op Cord

Deficit

2.4% 3.4% 2.2%

Intra-op

Unplanned Stage

1.4% 0.0% 1.6%

Intra-op Vessel /

OrganI njury

0.5% 0.0% 0.5%

High blood loss in PSO’s

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Postoperative complications

Complication ALL Primary Revision

Post-op Acute Respiratory

Distress/Failure

2.8% 0.0% 3.3%

Post-op Arrhythmia 1.5% 0.0% 1.7%

Post-op Bowel Bladder

Dysfunction 14.0% 10.3% 14.6%

Post-op Cauda Equina Deficit 1.0% 0.0% 1.1%

Post-op Deep Infection 4.3% 6.9% 3.9%

Post-op DVT 1.9% 0.0% 2.2%

Post-op Motor Deficit 10.2% 6.9% 10.7%

Postoperative complications

Complication ALL Primary Revision

Post-op Optic Deficit 0.5% 3.4% 0.0%

Post-op PE 2.4% 3.4% 2.2%

Post-op Pneumonia 1.5% 0.0% 1.7%

Post-op Reintubation 0.5% 0.0% 0.6%

Post-op Sepsis 1.0% 0.0% 1.1%

Post-op Tracheotomy 0.5% 0.0% 0.6%

Post-op Unplanned Return OR 14.0% 17.2% 13.5%

High rate of return to OR within the first year

Revision Rates

Primary PSO and Revision PSO groups

– implant failure no statistical difference

– (R=4.48%, P=5.41%)

– non-union no statistical difference

(R=3.59%. P=5.41%).

ALL Primary Revision Odds ratio 95% CI

3M 8.1% 2.7% 9% 3.5 [0.46;27.26]

Between

3M and 1Y

6.5% 5.4% 6.7% 1.3 [0.25;5.76]

Before 1Y 14.2% 8.1% 15.2% 2 [0.59;7.01]

Discussion

PSO were primarily performed for sagittal

plane deformity in Revision and Primary

cases as Hedlund reported

The operative time , blood loss and

infection rate was not statistically different

and similar to other reports

The most common level was L3

Angular Correction in Primary 27 deg and

Revision 24 deg was similar to reports of

25-30 range in the literature

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Discussion

Pelvic Mismatch to 0 postoperatively

– Primary PSO 81.1%

– Revision PSO 58.8%

Better ability to correct pelvic tilt in a

primary situation than the revision situation

with a previous lumbo-sacral fusion

Discussion

The motor deficits not statistically different

– Primary PSO 6.9%

– Revision PSO 10.7%

– The neurologic complication rate has been

reported to be 11% by Buchowski et al.

Revision Rates High up to 14 % in the first

year

– needs more detailed analysis

Conclusion

Pedicle Subtraction Osteotomy may be

performed in a Primary and Revision adult

spinal deformity patient

– Similar sagittal correction and complication

rates.

– Primary PSO patients are more likely to

achieve better spino-pelvic realignment.

67 yo female Multiple Surgeries

Severe Low back

pain

Decompensated

coronally and

sagittaly

Normal neurology

Smoker

Morphine pump

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Surgical Plan ?

Anterior

release/resectio

n and Posterior

Fusion

Pedicle

subtraction

osteotomy

Vertebral

Column

Resection

Assymetric Pedicle Subtraction

Osteotomy Conclusion

Useful in revising Sagittal Plane

deformities

Adequate bony resection and dissection of

the nerve roots is mandatory

Using temporary rods and a table that can

bend is helpful

Consider anterior L5-S1 structural support

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Thank You