The Dynamic Mobility of Vertebral Compression Fractures

Volume 18:24-29, 2003 JBMRFERGUS McKIERNAN, RON JENSEN, TOM FRACISZEWSKI

Marshfield Clinic, Wisconsin, USA

Report: R3 范姜治澐Supervisor: 李晏瑤主任

Introduction Kyphoplasty

Restore vertebral height Restore sagittal alignment Reduce chronic morbidity

Both vertebroplasty and kyphoplasty relieve fracture pain

Introduction

Dynamic mobility was seen in many vertebral compression fractures (VCFs)

Improve sagittal alignment can be also achieved during vertebroplasty

To define the magnitude and nature of dynamic mobility

Materials & methods

41 patients, 65 VCFs

Vertebral fracture pain (local knocking pain), impair activities, failure of medical therapy, technical feasibility, absent of contraindication

Pre-op evaluation Standing A-P and lateral view centered on

index vertebra Supine cross-table lateral view STIR-MRI

4-in foam bolster

Index vertebra

Pre-op evaluation Dynamic fracture mobility Non-mobile fixed compression fracture

Pre-op evaluation Intravertebral clefts: low resistence, confluented re

servoirs for PMMA

Intravertebral gasSignal void

PMMA fixation

Digitizing the lateral view Hp: ab Hm: cd Ha: ef Lateral vertebral area (LVA):

ab x ae Kyphotic angle (Ka): inters

ection of lines ae, bf

Pre-op evaluation Fracture severity:

Mild (20-25%) Moderate (25-40%) Severe (> 40%)

OP method

General anesthesia Padded prone in extension Mono- or bi-pedicular or para-pedicular Barium-fortified PMMA Kept supine 4h post-op Dismissed the next day, follow-up 2 week

s later

Results

41 patients (28 F, 13 M) 46 procedures, 65 VCFs Mean age: 75.4 y/o Mean fracture age: 117 days 18 patients (44%) had at least one mobile

VCF 23 mobile (35%), 42 non-mobile (65%)

Results Bimodal distribution (midthoracic and T-L juncti

on) Fracture at T-L junction: 17 of 26 (65%) mobile Intravertebral clefts presented in every mobile fr

acture, absent in every non-mobile (p<0.001)

T-L junction other

Mobile 17 (74%) 6

Non-mobile 9 (21%) 33

Results 18 of 23 mobile fractures were severe, 5

were moderate

Post-op Absolute increase P value

Hp + 15%

Hm + 93% P<0.001

Ha + 106% (42%70%) 8.41 +/- 0.4mm P<0.001

LVA + 67% (48% 80%) P<0.001

Ka + 40% (-7.18°) P<0.001

Results Mobile fractures underwent vertebroplasty earlier

(89 vs 133 days) (p=0.15)

1.33 fractures per patient in patients with mobile fracture

1.83 fractures per patient in patients with only fixed fractures (p=0.29)

Results Both mobile and non-mobile fractures repor

ted significant pain relief post-op

No clinical adverse events

4 small intradiscal cement leaks, 1 leak into the anterior spinal venous plexus

Discussion 1/3 of all fractured vertebrae were mobile

Significant improvement in Ha, Hm, LVA and Ka

Most mobile fractures occurred at T-L junction (where bears greatest dynamic load)

Presence of intravertebral clefts

Implications Fracture morphology (crush, biconcave, wedge) an

d severity need to accommodate the dynamic deformity

Vertebral height variance attributed to measurement error or “rebound”

Epidemiologic miscalculation and erroneous conclusions from therapeutic trials in which VCFs is the primary outcome

Discussion

Vertebral fracture mobility predicated on the “permissive” corticocancellous disruption, whether intrinsic or induced

More painful in mobile fractures (afferents from adjacent periosteum and ligment)

Discussion Mechanisms of pain relief from vertebroplasty:

Mechanical Neurolytic Thermal Chemical

Organization of hematoma and cicatrization of surrounding soft tissue result in early pain reduction

Discussion Kummel’s disease

Post-traumatic ischemic necrosis and collapse of vertebral body

Osteoporotic elders with T-L junction fractures

Risk for delayed ischemic necrosis Intravertebral vacuum cleft = Kummel’s sig

n Shared final pathway for certain high and lo

w energy vertebral injuries

Limitation

Supine extension radiographic technique needs to be standardized

Limited patient numbers

Conclusion Dynamic fracture mobility must be

considered when performing vertebral augmentation, or any intervention that claims vertebral height restoration

Thanks for your attention !!