HISTORY
A 60-year-old woman, diagnosed with lung adenocarcinoma, sought medical relief for intense back pain. The neurological exam revealed a slight deficit in strength and degree of left leg extension, without tone or sensibility deficits or atrophy of the lower extremities. She showed an unsteady gait and intense back pain in the 24 hours before the exam. She rated her pain as nine on a numerical rating scale (NRS) with no pain assigned zero and the most intense pain ever experienced given a 10.
Fast spin-echo MRI of the entire vertebral column demonstrated metastatic infiltration and collapse of the left element of the vertebral body at T11. The posterior portions were displaced against the surface of the spinal cord without cord compression. The lesion also extended to and infiltrated the homolateral costovertebral joint (Figure 1).
Percutaneous vertebroplasty was performed with 7 mL of polymethylmethacrylate acrylic cement under fluoroscopic guidance. At the end of the procedure, which was without radiological and clinical complications, the patient was maintained in a prone position and a noncontrast CT scan was performed to check results (Figure 2). An evaluation of the bone window at the level of the T11 vertebral body indicated the PMMA was in the normal position inside the vertebral body.
Severe back pain (NRS = nine) returned within 24 hours postoperatively and was treated with nonsteroidal anti-inflammatory drugs and opioids in a continuous infusion. Perceived pain intensity fell to six during the administration of analgesics but returned to nine a day after infusion was suspended.
A second postoperative spinal MRI revealed PMMA inside the neoplastic tissue. Imaging indicated it was spreading into the left component of the lesion and causing extrusion of tumor into the anterior subarachnoid space, which compressed the left anterolateral spinal cord at this level (Figure 3).
DIAGNOSIS
Postprocedural complication of vertebroplasty due to the extrusion of a neoplastic lesion under the pressure from injected PMMA acrylic cement, rather than PMMA leakage.
Radiotherapy resolved the complication, producing pain remission and complete recovery of inferior limb motility within 30 days of the intervention.
DISCUSSION
From 50% to 97% of patients commonly experience pain relief within 24 hours after percutaneous vertebroplasty for intractable back pain from vertebral collapse due to osteoporosis, myeloma, or metastasis.
The complication rate is usually low, but it can be as high as 10% for patients with malignant tumors. Transient radiculopathy, reported in 3% to 6% of patients, is well treated with steroids and anti-inflammatory medications. Transient neurological deficits are observed in about 5% of patients because of cement leakage from the vertebral body fractures, typically located close to the posterior vertebral body wall.
A 2003 study demonstrated that vertebroplasty produces higher intravertebral pressures in vertebrae containing a simulated lytic metastasis than in intact vertebrae. Our case demonstrates a complication from the extrusion of the neoplastic lesion under the push of the PMMA rather than leakage of the cement.
We stand by the therapeutic choice of percutaneous vertebroplasty for this patient, however. The disruption of the posterior element is not an absolute contraindication for the procedure, especially in this case, where the patient did not show an unstable fracture.
This case report was condensed from “Percutaneous vertebroplasty and spinal cord compression: a case report (Journal of Radiology Case Reports, Citation: Radiology Case. 2009;3[3]:17- 20). The full version, including interactive features, can be reviewed at www.radiologycases.com/index.php/radiologycases/issue/view/37.
Contributing authors Drs. Ilaria Morghen and Roberto Zoppellari are affiliated with the anesthesiology and critical care department at St. Anna University Hospital in Ferrara, Italy. Drs. Massimo Borrelli and Andrea Saletti practice in the neuroradiology service at the same facility.
