Neuroradiology Case of the Month

April 2002

Edward P. Lin, Manoj Ketkar, MD and P.L. Westesson, MD, PhD, DDS

Clinical Presentation: An 81-year-old male with severe osteoporosis was referred with a complaint of lower back pain. Vertebroplasty was performed at the L4 level for an acute vertebral body fracture. After the procedure, the patient developed left L5 radicular pain.

Radiologic and Clinical Findings: MRI scan (Fig. 1) demonstrated an acute L4 vertebral body fracture.

A post-vertebroplasty CT study (Fig. 2) demonstrated homogenous dispersion of bone cement throughout the L4 vertebral body. It also showed extravasation of bone cement into the left anterior epidural space and into the left lateral recess.

Cement extravasation in the left anterior epidural space most likely caused this patient’s L5 radicular pain. Because the pain did not improve over the next seven weeks, the patient elected to proceed with surgical intervention. Bilateral L4 laminectomies and a partial left medial facetectomy were performed, and a 2.1 cm. firm, white mass was removed from the left lateral recess (Fig. 3). The patient’s radicular symptoms resolved after recovery.

Diagnosis: Post-Vertebroplasty Nerve Decompression.

Figure 1 (A&B): Sagittal T2-weighted and sagittal T1-weighted post contrast MRI of lumbar spine reveal an acute fracture of the L4 vertebral body.

Figure 2 (A&B): Post-vertebroplasty axial CT scan through the L4/5 disc space level and sagittal reformatted CT images through the lumbar spine reveal extravasation of the bone cement into the left anterior epidural space and left lateral recess
Fig. 3. Specimen photograph of the cement removed from the epidural space.

Discussion: Percutaneous vertebroplasty is an effective treatment for pain relief and the stabilization of fractured vertebrae [1-4]. It entails the injection of polymethlmethacrylate into the vertebral body under fluoroscopic or CT guidance via percutaneously introduced needles. Compression fractures can be found in patients with osteoporosis, vertebral angiomas and osteolytic diseases [1-4].

Complications of vertebroplasty include increased pain, spinal cord and nerve root compression secondary to cement leakage, pulmonary embolism, and infection [1,2,4-6]. Extravasation of cement into the epidural space or through the foramina constitute the major complications of vertebroplasty [1,3-5].

Leaks have been found in the spinal canal, the neural foramina, adjacent vertebral discs, para-vertebral soft tissue and the lumbar venous plexus [4]. The leakage of any cement outside the vertebral body occurs in 30-75% of cases, but it causes significant neurological symptoms only in a minority of cases [1,3-5].

While the low complication rate and benefits of vertebroplasty in reducing pain and in stabilizing fractured vertebrae are promising, adverse outcomes can be further reduced primarily by decreasing the risk for leakage and secondarily by surgical intervention.

Acknowledgement: The authors wish to thank Margaret Kowaluk for her help in preparing this and other Neuroradiology cases of the month.

References:

1. Deramond H. et al. Percutaneous vertebroplasty with polymethylmethacrylate. Technique, indications, and results. Radiologic Clinics of North America. 36(3):533-46, 1998.
2. Cyteval C. et al. Acute osteoporotic vertebral collapse: open study on percutaneous injection of acrylic surgical cement in 20 patients. AJR. American Journal of Roentgenology. 173(6):1685-90, 1999.
3. Cortet B. et al. Percutaneous vertebroplasty in the treatment of osteoporotic vertebral compression fractures: an open prospective study. Journal of Rheumatology. 26(10):2222-8, 1999.
4. Cotten, A et al. Percutaneous vertebroplasty for osteolytic metastases and myeloma: effects of the percentage of lesion filling and the leakage of methyl methacrylate at clinical follow-up. Radiology. 200:525-530.
5. Garfin SR et al. New technologies in spine: kyphoplasty and vertebroplasty for the treatment of painful osteoporotic compression fractures. Spine. 26(14):1511-5, 2001.
6. Martin JB. Vertebroplasty: clinical experience and follow-up results. Bone. 25(2 Suppl):11S-15S, 1999.