Heterotopic ossifications after vertebroplasty using calcium phosphate in osteoporotic vertebral compression fractures

Intervertebral Bridging Ossification After Percutaneous Kyphoplasty in Osteoporotic Vertebral Compression Fractures

BACKGROUND

Percutaneous kyphoplasty (PKP) is effective in treating osteoporotic vertebral compression fractures (OVCFs). Intervertebral bridging ossification can sometimes be detected after surgery, but studies related to its formation mechanism and its influence on outcome are few.

CASE DESCRIPTION

We reviewed patients' radiologic images and found 7 patients in whom intervertebral bridging ossification developed after PKP. Their personal and clinical information was recorded. The 7 patients had an average age of 63.43 ± 4.79 years. Injured levels included L1 (1 patients) and L2 (1 patient). GeneX and PMMA cement were respectively applied. Both the Cobb angle and the VAS scores were significantly improved after surgery, but all surgical vertebrae showed recollapse combined with larger Cobb angle at the last follow-up visits. In 1 patient the new-onset T11 fracture developed 29 months after surgery.

CONCLUSIONS

We deemed that spinal degeneration, mechanical instability, bone cement, and fracture pattern are all potential promoting factors for intervertebral bridging ossification. Solid bridging ossification may increase local spinal stability, but it also increases the risk of adjacent vertebral fractures.

Demineralization after balloon kyphoplasty with calcium phosphate cement: a histological evaluation in ten patients

PURPOSE

Balloon kyphoplasty (BKP) with calcium phosphate cement (CPC) is increasingly being used for spinal surgery in younger patients. In routinely performed follow-up CT scans we observed considerable areas of demineralization in CPC processed vertebrae in several patients. To rule out infections or inflammations histological examinations were planned for these patients.

METHODS

Ten patients (23-54 years; six men) with significant demineralization areas in CT scans after CPC balloon kyphoplasty were selected. Punch biopsies from these areas were taken in local anesthesia using a biopsy needle. One half of the specimen was decalcified and embedded in paraffin, and sections were examined histologically using hematoxylin and eosin, Van Gieson, and trichrome staining. The second half of the specimen was cast directly in methyl methacrylate and sections were examined by Paragon and von Kossa/Safranin staining. Stained slides were viewed under light microscopy.

RESULTS

Bone-punch specimens were taken at 17.5 months (mean) after BKP with CPC. In most cases, the cement was well surrounded by newly formed lamellar bone with very tight connections between the cement and new bone. Unmineralized areas were observed sporadically at the cement surface and adjacent to the implant. There were no pronounced signs of inflammation or osteolysis of adjacent bone. No complications were observed during or following patients' biopsy procedures.

CONCLUSIONS

CPC demonstrated good biocompatibility and osseointegration in clinical use, with no evidence of inflammation or osteonecrosis. Demineralized areas in CT scans could be a result of remodeling of the cancellous bone in vertebral bodies.

Therapeutic efficacy of vertebroplasty in osteoporotic vertebral compression fractures with avascular osteonecrosis: a minimum 2-year follow-up study

STUDY DESIGN

A retrospective review of clinical and radiological parameters.

OBJECTIVE

To assess for at least 2 years the radiological and clinical outcomes of patients who underwent polymethylmethacrylate (PMMA) vertebroplasty to treat osteoporotic vertebral compression fractures with avascular necrosis.

SUMMARY OF BACKGROUND DATA

Recently, osteoporotic vertebral compression fractures with avascular osteonecrosis have been treated with percutaneous vertebroplasty. However, there have been no previous multiyear, clinical, and radiological studies of the results of vertebroplasty in the vertebral body with noninfected avascular osteonecrosis.

METHODS

Thirty patients were followed for at least 2 years after vertebroplasty. We retrospectively reviewed several parameters, including visual analogue scale score, Oswestry Disability Index, compression ratio, kyphotic angle, injection pattern of PMMA (interdigitation and solid mass), and morphological changes of the PMMA-cemented vertebral bodies. RESULTS.: The vertebral height and kyphotic angle were significantly corrected after vertebroplasty. However, the restored vertebral height recollapsed (P < 0.05), and the kyphotic angle became aggravated (P < 0.05) during the 2 years or longer of postoperative follow-up. Visual analogue scale and Oswestry Disability Index were significantly decreased at postoperative day 1. However, visual analogue scale and Oswestry Disability Index were significantly increased at 24 months postoperatively. There were 4 kinds of morphological changes of the injected PMMA-cemented vertebral body, including heterotopic ossification, fusion with the adjacent vertebral body, bone cement fragmentation and migration, and development of a radiolucent line around the PMMA mass in the vertebral body.

CONCLUSION

After vertebroplasty, the compression and kyphosis of avascular necrotic vertebral bodies progressed continuously for 2 years or longer. Vertebroplasty may not provide sufficient stability. Therefore, we strongly recommend that strict observation and follow-up be used after vertebroplasty.

Current management review of thoracolumbar cord syndromes

BACKGROUND CONTEXT

Injuries to the thoracolumbar spine may lead to a complex array of clinical syndromes that result from dysfunction of the anterior motor units, lumbosacral nerve roots, and/or spinal cord. Neurologic dysfunction may manifest in the lower extremities as loss of fine and gross motor function, touch, pain, temperature, and proprioceptive and vibratory sense deficits. Two clinical syndromes sometimes associated with these injuries are conus medullaris syndrome (CMS) and cauda equina syndrome (CES).

PURPOSE

To review the current management of thoracolumbar spinal cord injuries.

STUDY DESIGN

Literature review.

METHODS

Index Medicus was used to search the primary literature for articles on thoracolumbar injuries. An emphasis was placed on the current management, controversies, and newer treatment options.

RESULTS/CONCLUSIONS

After blunt trauma, these syndromes may reflect a continuum of dysfunction rather than a distinct clinical entity. The transitional anatomy at the thoracolumbar junction, where the conus medullaris is present, makes it less likely that a "pure" CMS or CES syndrome will occur and more likely that a "mixed" injury will. Surgical decompression is the mainstay of treatment for incomplete spinal cord injury (SCI) and incomplete CMS and CES. The value of timing of surgical intervention in the setting of incomplete SCI is unclear at this time. This review summarizes the recent information on epidemiology, pathophysiology, diagnosis, and controversies in the management of thoracolumbar neurologic injury syndromes.