Optimizing Vertebral PMMA Augmentation of Metastasis to Prevent or Minimize Post kyphoplasty Fracture Progression- Refracture Eric Lis, M.D. Memorial Sloan-Kettering Cancer Center Director Neurointerventional Radiology Associate Attending, Radiology Assistant Professor of Radiology, Cornell-Weill Medical College

Percutaneous balloon kyphoplasty can be effective in controlling the mechanical pain associated with vertebral body collapse deformities associated with metastatic disease. Disease progression at the augmented level Disease progression at adjacent levels Radiation therapy regional effects- Post RT tumor inflammation Post RT myositis Involved field adjacent level fracture Post kyphoplasty fracture progression-refracture For a variety of reasons patients may develop recurrent or progressive back following the procedure Possible cause for recurrent back pain following kyphoplasty

Post kyphoplasty Fracture Progression Possible issues as a result of post kyphoplasty fracture progression May be mistaken for disease progression Can result in increased back pain after a period of decreased pain Can result in increased kyphosis-sagittal imbalance Can result in increased strain on the posterior elements-pedicle fractures Ultimately may require open surgical intervention-posterior stabilization By providing better filling of the collapse vertebral body at the time of the kyphoplasty there is the potential to prevent or minimize further collapse

Typical Examples of Fracture Progression

Example #1 Colon cancer with L1 metastasis Mild collapse deformity Extensive marrow infiltration L1 Early epidural involvement Mechanical and biological back pain referable to L1 Good candidate for kyphoplasty prior to high dose SRS

Example #1 Colon cancer with L1 metastasis Post kyphoplasty CT myelogram Patient reports decreased movement related back pain Undergoes high dose SRS 24Gy/1fx Visual pain score from 10/10 to 4/10

Example #1 Colon cancer with L1 metastasis 2 months Post kyphoplasty and SRS Returns to Urgent Care Center Pt doing well until he acutely develops recurrent low back pain and leg weakness Imaging shows fracture progression at L1 Treated with decompression and posterior stabilization

Example #2 Colon cancer with T12 metastasis S/P Kyphoplasty and SRS Mild to moderate collapse deformity Pain reduced form 8/10 to 4/10

Example #2 Colon cancer with T12 metastasis 8 weeks S/P Kyphoplasty and SRS Progressive collapse deformity Slight increased kyphosis Pain scores plateaus at 4/10 Patient reports increased back pain with prolonged standing-activity Some improvement with PT and postural training

Example #3 Renal cell cancer L3 and L4 metastasis Kyphoplasty followed by SRS Intraoperative CT and X-ray Moderate collapse deformity L4 Pt reports modest reduction of back pain

Example #3 Renal cell cancer L3 and L4 metastasis Kyphoplasty followed by SRS I month f/u Progressive collapse L4 Low back pain unchanged

Example #3 Renal cell cancer L3 and L4 metastasis Kyphoplasty followed by SRS 4 month f/u CT Progressive collapse L4 The progressive collapse causes posterior displacement treated tumor into ventral epidural space, “tooth paste effect” Low back pain increasing Patient not keen on any further intervention but may ultimately will require surgical decompression-stabilization 1 month 4 month

Example #3 Renal cell cancer L3 and L4 metastasis Kyphoplasty followed by SRS 4 month f/u CT Progressive collapse L4 Overall fracture progression of 29% compared to baseline post kyphoplasty Low back pain increasing Patient not keen on any further intervention but most likely will require surgical decompression-stabilization 1 month 4 month

Post Kyphoplasty Fracture Progression Take home message from the 3 previous examples In the setting of metastatic disease there can be progressive collapse that continues after the kyphoplasty Fracture progression can result in increased morbidity - increased pain -Neurological symptoms - Further surgical intervention Fracture progression most often is stops at the superior and inferior margins of the PMMA, i.e. The vertebral body fractures down to the cement Possible Solution Provide more complete filling of the vertebral body, particularly filling from endplate to endplate,at the time of the kyphoplasty could potentially prevent or minimize further collapse

Post Kyphoplasty Fracture Progression Potential factors that limit the amount of cement that can be infused into a pathological fracture Pre-existing epidural disease Destruction of the walls of the vertebral body - increased risk of PMMA extravasation -Epidural or foraminal extravasation - venous and paraspinal extravasation

Post Kyphoplasty Fracture Progression Strategies to optimize cement augmentation Review pre kyphoplasty cross sectional image MRI and CT Any epidural or foraminal encroachment Type of metastasis-lytic or mixed Location of the lesion in the vertebral body Any residual normal appearing bone present Integrity of vertebral body bony cortex Are the superior and inferior endplates intact Asses adjacent paravertebral structures to determine if an extra- pedicular needle placement is a potential option if needed

Strategies to optimize cement augmentation T9 pathological collapse Mild canal compromise Extensive lytic destruction Segmental cortical disruption

Strategies to optimize cement augmentation T9 pathological collapse Unusually good height restoration How to best preserve the restored height?

Strategies to optimize cement augmentation T9 pathological collapse How to best preserve the restored height? Infuse the PMMA unilaterally leaving one bone tamp up. The inflated bone tamp will potentially preserve much of the restored height that often decreases as the bone tamps are deflated

Strategies to optimize cement augmentation T9 pathological collapse How to best preserve the restored height? Infuse the PMMA unilaterally leaving on bone tamp up. Continue to infuse unilaterally till approaching posterior third of the vertebral body.

Strategies to optimize cement augmentation T9 pathological collapse How to best preserve the restored height? The contralateral bone tamp is then slowly deflated.

Strategies to optimize cement augmentation T9 pathological collapse How to best preserve the restored height? The contralateral bone tamp is then slowly deflated.

Strategies to optimize cement augmentation T9 pathological collapse How to best preserve the restored height? The contralateral bone tamp is then slowly deflated.

Strategies to optimize cement augmentation T9 pathological collapse How to best preserve the restored height? PMMA is then infused into the contralateral side

Strategies to optimize cement augmentation T9 pathological collapse How to best preserve the restored height? PMMA is then infused into the contralateral side while PMMA infusion is also continued on the ipsilateral side

Strategies to optimize cement augmentation T9 pathological collapse Good top to bottom fill of T9. The potential for further significant collapse has been reduced

Strategies to optimize cement augmentation Combining vertebroplasty and kyphoplasty Vertebroplasty effect diffuse PMMA into normal the bone

Strategies to optimize cement augmentation Combining vertebroplasty and kyphoplasty L1 lung cancer metastasis

Strategies to optimize cement augmentation Kidney cancer -T12 metastasis 35% lytic destruction New onset back pain with bending High dose stereotactic radiosurgery planned Kyphoplasty to be performed prior to radiation therapy

Strategies to optimize cement augmentation Pre-kyphoplasty assessment At risk for fracture progression junctional zone Lytic destruction RT Need to augment both lytic tumor and more normal appearing bone Need to maximize PMMA from endplate to endplate to minimize fracture progression

Strategies to optimize cement augmentation Renal cancer T12 kyphoplasty

Bone Tamp inflated in Lytic component of lesion (low pressure) Contralateral bone tamp barely inflated (higher pressure)

Strategies to optimize cement augmentation Renal cancer T12 kyphoplasty Initial PMMA fill Lytic component being filled but will need to stop as PMMA approaches posterior third of the VB Vertebroplasty effect on the left

Strategies to optimize cement augmentation Renal cancer T12 kyphoplasty The right needle is pulled back and redirected more laterally to target more of the lytic metastasis

Strategies to optimize cement augmentation Renal cancer T12 kyphoplasty The right needle is pulled back and redirected more laterally to target more of the lytic metastasis

Strategies to optimize cement augmentation Renal cancer T12 kyphoplasty Bone tamp reinserted and inflated in the lytic lesion abutting previously infused PMMA

Strategies to optimize cement augmentation Renal cancer T12 kyphoplasty Additional PMMA infused into the lateral and inferior aspect of the lytic metastasis

Strategies to optimize cement augmentation Renal cancer T12 kyphoplasty Both needles are pulled back into the pedicle and redirected superiorly to allow better filling endplate to endplate

Strategies to optimize cement augmentation Renal cancer T12 kyphoplasty Both needles are pulled back into the pedicle and redirected superiorly Bone Tamps are reinserted

Strategies to optimize cement augmentation Renal cancer T12 kyphoplasty Use of the beveled stylet helps direct the needle superiorly

Strategies to optimize cement augmentation Renal cancer T12 kyphoplasty Bone Tamps are reinserted

Strategies to optimize cement augmentation Renal cancer T12 kyphoplasty PMMA now being infused into the superior aspect of T12

Strategies to optimize cement augmentation Renal cancer T12 kyphoplasty Post Kyphoplasty x-ray

Strategies to optimize cement augmentation Renal cancer T12 kyphoplasty Good PMMA augmentation of the lytic disease Initial PMMA infused was 2ml Additional PMMA infused was 3ml for a total of 5 ml PMMA

Strategies to optimize cement augmentation Renal cancer T12 kyphoplasty Good “top to bottom” augmentation 2 month f/u is without evidence of fracture progression

Strategies to optimize cement augmentation Preliminary findings Retrospective review 30 patients with oligo-metastatic spine disease and symptomatic pathological fractures 33 levels underwent kyphoplasty All augmented vertebrae were either treated with stereotactic radiosurgery prior to the kyphoplasty or were scheduled to have SRS done after the kyphoplasty All treated levels underwent kyphoplasty needle repositioning to increase the amount of PMMA could be infused into the vertebral body

Strategies to optimize cement augmentation Preliminary findings Retrospective review 30 patients, M:F 21:9 Average Age: 59 yo Most common diagnosis: Metastatic RCC, N=16

Strategies to optimize cement augmentation Preliminary findings Retrospective review 30 patients, M:F 21:9 Average follow-up: 9 months (1-32 months) Average vertebral body destruction: 67% Average pain score pre-kyphoplasty: 7.8/10 Average pain score post kyphoplasty: 2.9/10 Average volume PMMA prior to needle repositioning: 6.1ml Total Average volume PMMA: 9ml % increased PMMA: 48% Post Kyphoplasty fracture progression: 39% (N=13/33) Average loss VB height : 18% Average loss VB height in mm: 3.5mm

Strategies to optimize cement augmentation Preliminary findings Retrospective review Post Kyphoplasty fracture progression: 39% (N=13/33) Average loss VB height : 18% Average loss VB height in mm: 3.5mm Two of the thirty patients were taken to surgery at one month secondary to disease progression. No patients in this group required open stabilization secondary to mechanical instability

Strategies to optimize cement augmentation Preliminary findings L1 metastatic leiomyosarcoma 70% lytic destrucrion

Strategies to optimize cement augmentation Preliminary findings

Pre kypho Post kypho 6 Months13 Months

Strategies to optimize cement augmentation Preliminary findings 20 Months L1 metastasis s/p kyphoplasty and SRS Left unilateral fracture progression 23% fracture progression 6mm loss VB height post kypho Fractured “down to cement” No catastrophic collapse requiring any further surgical intervention Pain score from 7/10-1/10 RT induced adjacent level fracture tx’ed with kyphoplasty

Strategies to optimize cement augmentation Conclusion 20 Months By Providing more complete filling of the vertebral body, particularly filling from endplate to endplate,at the time of the kyphoplasty could potentially prevent or minimize further collapse

Thank You Eric Lis, M.D. Memorial Sloan-Kettering Cancer Center Director Neurointerventional Radiology Associate Attending, Radiology Assistant Professor of Radiology, Cornell-Weill Medical College