Dr W J Rennie MSc,FRCR

Musculoskeletal Radiologist

Honorary Senior Lecturer

Leicester Royal Infirmary

winston.rennie@uhl-tr.nhs.uk

The role of Cement

Augmentation in the

Prevention of Spinal

Insufficiency Fractures

–Albert Einstein

“Not all questions that can be answered are

worth asking and not all questions that are

worth asking can be answered

Acknowledge

Dr B Georgy- San Diego

Prof P Munk- Vancouver

Mr A Qureshi- PhD Orthopaedics

Dr R Botchu Msk Rad

Layout

• Thoughts

• Current Literature

• Review Spinal Biomechanics- Fracture

• My Experience

• Cases

• Summary

Surgical Procedures with No treatment

Effect Vs Conservative Management

Level 1 Evidence

• Scaphoid waist fracture fixation

• Surgical repair - Achilles Tendon ruptures

• Major limb Fracture fixation

Literature

Search

NEJM

Prevention

Insufficiency Fractures

Hip fractures NEJM 1992

Literature Search

• ‘Osteoporosis’, ‘Prophylactic’, ‘cement’, ‘fracture

prevention’

• Recent articles 2009- 2014

• 7 relevant articles Pubmed

• Only 3 on Spine

Prophylactic Femoroplasty

• Fracture prevention by

femoroplasty--cement

augmentation of the proximal

femur. Beckmann J et al. J

Orthop Res. 2011

Nov;29(11):1753-8.

• Limited V-shaped cement

augmentation of the proximal

femur to prevent secondary hip

fractures. Fliri L et al.

Biomater Appl. 2013

Jul;28(1):136-43.

Literature Against

• The effect of cement augmentation on the load

transfer in an osteoporotic functional spinal unit: finite-

element analysis.Polikeit A, Nolte LP, Ferguson SJ.

Spine (Phila Pa 1976). 2003 May 15;28(10):991-6.

• Material changes in osteoporotic human cancellous

bone following infiltration with acrylic bone cement for

a vertebral cement augmentation. Baroud G, Nemes

J, Ferguson SJ, Steffen T. Comput Methods

Biomech Biomed Engin. 2003 Apr;6(2):133-9.

FEA Cement Augmentation

Vertebroplasty: Patient and treatment variations studied through parametric computational models.

Wijayathunga VN et al. Clin Biomech (Bristol, Avon). 2013 Oct;28(8):860-5.

–White AA, Panjabi MM. Clinical biomechanics of spine.

Abnormal flexion-extension mobility - Paradoxical motion.

Kinematics of Spine Chap. 2; 89.

Concept of stability

“Spine is stable when it is able to resist

progressive deformity under physiological

loading”

Spinal Stiffness

• Euler 1744- Mathematical

theory for slender columns

• Critical Load (CL)directly

related to stiffness

• In vitro CL for LSpine 90N

• In vivo CL for Lspine

1500NS.P. Timoshenko, J.M. Gere (Eds.), Mechanics of

materials, Van Nostrand Reinhold, New York, 1972

Stabilising Subsystem

Insufficiency Fracture?

• Fracture -Break in the cortex

• Multidirectional

• Significant Force- Trauma

• Single event

• Insufficiency Spine- Failure of

Bone

• Compression

• Gravity- Atraumatic

• Cannot be attributed to a single

event

Vertebral structureClinical Anatomy of the Lumbar Spine and Sacrum, 3rd Edition, Nikolai Bogduk, 1997, Churchill Livingston Elsevier, ISBN 0 443

18

Vertebral

cortex/trabecular ratio

A P

Stable Arch

Spinal Fracture Biomechanics

20

A P

Spinal Fracture

21

PA

Sagittal Balance

The center of gravity (G) moves forward

Large bending moment created

Posterior muscles and ligaments must counterbalance increased bending- Pain

Osteoporotic anterior spine must resist larger compressive stresses-New fractures

G

Vertebral fracture healing

• Osteoporosis- Delayed bone healing?

• Lack of Callus formation in vertebrae

• Creeping Substitution

• Bone Grafts in spine

• Vertebral clefts- Pseudoarthrosis= Non Union

Hagasewa K et al Spine, 1988;23(20) 2201-06

Giannoudis P et al. Injury, Mar 2007;38(1),S90-99

Literature -1

• Biomechanical effectiveness of prophylactic vertebroplasty

• J Neurosurg Spine 8:442–449, 2008

• 12, 3 segment functional units- T12-L2

• Incremental loads up to 3.5x body weight

• Qct pre and post L1 augmentation

• Fractures occurred only after loads >2-3 times body weight

Literature 2

Prophylactic Vertebroplasty May Reduce the Risk of Adjacent Intact Vertebra From

Fatigue Injury

SPINE Volume 34, Number 4, pp 356 –364

• Biomechanical study on 14, 5 level thoracic spinal segments

• Divided prophylactic & standard groups

• Central vertebra augmented

• Compressive fatigue loading

• Strain Compliance -cortical shell and height

Schematics of Specimen

Percentage of height loss after loading

Deformation after fatigue loading

Prophylactic Augmentation

• Prophylactic augmentation strengthens osteoporotic vertebrae,

decreases the progression of vertebral height loss, reduces the

anterior body shift, and hence protects the adjacent intact

vertebra from elevated flexion bending.

• Vertebra is osteoporotic and adjacent level is located at pivot or

lordotic level of spinal column

• Prophylactic augmentation may be an option to prevent the

AVF.

• Spine (Phila Pa 1976). 2009 Feb 15;34(4):356-64.

Uni or

Bipedicular?

Targeted cement Placement

32

Benzel’s Column Theory

33

QoL PVP Leicester n=104

QoL in Myeloma Patients

QoL in Osteoporosis

Quality of Life n=104

63

Case 1

• 82 male

• Osteoporosis,Degenerative joint disease,

Kummels disease, Multiple haemangiomata,

Mitral valve repair, Chronic pleural effusion.

• Pre assessment EQ 5D HS 50, M 2 SC 1 UA 3

PD 2 AD 2

Examination

• Erythema ab Igne over the region

• Focal tenderness to percussion

• 7month TTPre assessment clinic

• 11months RTT

T11 - Fracture Cleft

Case 2

• Xray “Worsening Osteoporosis T score -4.0”

• MRI - 3/12

• Pre Assessment 3/12

• Procedure 5/12

• RTT 11/12

Cavity fill Vs Standard Vertebroplasty

Case 3 Osteoporotic 80 female Fracture T5 and L2

Role of Prophylactic Cement

Augmentation• Redefine an osteoporotic fracture?

• Is loss of height too late for augmentation?

• Biomechanical segment cement augmentation

• ‘Prophylactic’ augmentation in unstable segments

• Targeted cementing with channel creation

• Columnar construct to prophylactic cementing

• Imperative that complications are low/nil- High Viscosity

“nanos gigantum humeris insidentes"

– Sir Isaac Newton

in a letter to Robert Hooke 1676

“If I have seen further it is by standing on the

shoulders of giants.”

winston.rennie@uhl-tr.nhs.uk