Method Relieves Pain From Vertebral Fractures in Myeloma

CLEVELAND—In research presented at the North American Spine Society, Isador Lieberman, MD, described a new approach to repair of vertebral compression fractures that may offer significant pain relief and other benefits to myeloma patients.

The technique, kyphoplasty, involves using a cannula and small balloon to pump up the collapsed vertebra, restoring much of its normal height and creating a cavity that can then be filled with bone cement.

Restores Height

The kyphoplasty method appears quite effective at restoring lost vertebral height and has little risk of cement extravasation, Dr. Lieberman said. Vertebroplasty by injection of low-viscosity liquid cement into the unreduced vertebral body is associated with cement extravasation rates as high as 65% in metastases and 30% in osteoporotic fractures.

Dr. Lieberman, of the Department of Orthopedic Surgery, Cleveland Clinic Foundation, had previously reported successful use of kyphoplasty in treatment of painful osteoporotic vertebral compression fractures in 30 patients (Spine 26:1631-1638, 2001).

That phase I study showed that kyphoplasty is safe and well tolerated in the patient groups treated (24 with osteoporosis unresponsive to nonoperative management, 6 with painful compression fractures from multiple myeloma), he said.

A significant amount of lost height was restored in 70% of the vertebral bodies treated. Cement leakage occurred in only 6 vertebrae treated (8.6%) and did not cause any clinical problems either immediately or during follow-up.

"With regard to kyphoplasty vs vertebroplasty, safety is important, but I think height restoration is slightly more important in myeloma patients," Dr. Lieberman told ONI in an interview.

Quick Pain Relief

Pain relief and clinical improvement occurred quickly, often in the first 24 hours, and restored some degree of mobility in all patients. Although the researchers were able to create fillable cavities in all vertebrae treated, Dr. Lieberman’s impression is that height can be restored more predictably if vertebral compression fractures are treated within 3 months of occurrence.

"Kyphoplasty may be worthwhile immediately after vertebral fracture in some high-risk patients to enable early mobilization and decrease mortality," he said.

The technique involves introduction of a cannula containing a small inflatable balloon (bone tamp) into the vertebral body. Inflating the bone tamp (KyphX, Kyphon, Inc., Sunnyvale, California) reduces the vertebral body back toward its original height while creating a cavity that can be filled with bone cement.

The cement filler is allowed to thicken until a 2-cm³ bolus suspended from a wooden spatula does not fall from the spatula. Then a cannula of cement is advanced through the working cannula; a stainless steel stylet is used to shove the cement into the cavity.

"This allows the cement to be applied at a considerably higher viscosity than injection through a 5-mL syringe and 11-gauge needle," he said. "The cement augmentation is also done with more control into the low-pressure environment of the preformed cavity than in conventional vertebroplasty." The procedure requires 45 to 75 minutes per vertebra.

Dr. Lieberman said that two phase II trials are on the drawing board. One will compare kyphoplasty to vertebroplasty. The other will test polymetholmethacrylate (PMMA) against other fillers. Three-dimensional volumetric CT scans will be used to measure restoration of vertebral volume as well as height.

Learning kyphoplasty is a straightforward process that involves a training course plus 10 cases under supervision, and Dr. Lieberman expects the procedure to eventually become a routine part of orthopedic practice.