Nobuo Kobayashi

Prophylactic Vertebroplasty: Cement Injection into Non-fractured Vertebral Bodies During Percutaneous Vertebroplasty

RATIONALE AND OBJECTIVES We investigated the efficacy of prophylactic cement injection into the vertebral body adjacent to fractured vertebra to prevent new fractures after percutaneous vertebroplasty (PV). MATERIALS AND METHODS Between February 2002 to August 2004, PV was performed for osteoporotic compression fractures in 89 consecutive patients. All patients underwent PV for only fractured vertebrae. Between September 2004 and October 2006, we performed prophylactic cement injection for 155 patients, with cement injected into the non-fractured vertebra adjacent to the fractured vertebra, immediately above the fractured vertebra in the same procedure. We evaluated the frequency of new vertebral fractures and the efficacy of prophylactic therapy. RESULTS In the non-prophylactic group, 15 of 89 patients (16.8%) developed new fractures within 3 months and 20 of 89 patients (22.4%) developed new painful compression fractures within a year after the first PV. These fractures occurred mostly in adjacent vertebra, particularly in the vertebra immediately superior to the treated one and occurred in the lower thoracic and upper lumbar spine. In the prophylactic group, 7 of 155 patients (4.5%) developed new compression fractures within 3 months and 15 of 155 patients (9.7%) developed new compression fractures within 1 year. Statistical analysis showed that fewer new fractures developed in the prophylactic group than in the non-prophylactic group at both 3 months (P = .0020, Fishers exact test) and 1 year (P = .0079). CONCLUSIONS Prophylactic cement injection into non-fractured vertebrae adjacent to fractured vertebrae may prevent new compression fractures after vertebroplasty for osteoporotic patients.

Pedicle Involvement on MR Imaging Is Common in Osteoporotic Compression Fractures

BACKGROUND AND PURPOSE: Pedicle involvement on MR imaging has been considered specific for malignancy. However, we also noted the findings in many patients with osteoporosis and hypothesized that it is not specific for malignant lesions. The aim of this study was to evaluate the prevalence of pedicle involvement in painful osteoporotic compression fractures and to determine whether the sign is specific for malignancy. MATERIALS AND METHODS: We retrospectively reviewed MR images and CT scans of 152 patients who underwent PV for painful compression fractures. There were 140 patients (225 vertebrae) with osteoporotic fractures and 12 patients (19 vertebrae) with malignant fractures. Three radiologists evaluated the degree and extent of signal-intensity changes of the pedicle on MR imaging by consensus. The CT findings were also evaluated. The χ2 test was used for statistical analyses. RESULTS: Of the 225 vertebrae of osteoporotic fractures and 19 vertebrae of malignant fractures, pedicle involvement on MR imaging was seen in 144 (64%) and 16 (84.2%) vertebrae, respectively, and there was no statistically significant difference (P = .065). Positive pedicle involvement in osteoporotic fractures was seen in 84 (77%) of 109 vertebrae with early-phase fractures (≤3 months) and 60 (51.7%) of 116 vertebrae with chronic-phase fractures (>3 months), and this was statistically significant (P < .001). Among 144 osteoporotic vertebrae that showed positive pedicle involvement on MR imaging, 45 (31%) showed pedicle fractures and 55 (38.2%) showed sclerotic change on CT. CONCLUSIONS: Pedicle involvement was seen frequently in patients with osteoporotic compression fractures and was not specific for malignancy in our study group.

Therapeutic effects of percutaneous vertebroplasty for vertebral metastases

PurposeWe have performed percutaneous vertebroplasty (PV) using polymethylmethacrylate (PMMA) for patients with vertebral metastases since 2002. This study investigated the therapeutic effects of PV on vertebral metastases.Materials and methodsA retrospective (2002–2008) review was conducted for 69 consecutive patien 141 metastatic vertebrae treated with PV using PMMA. The clinical background of the patients, visual analog scale (VAS), improvement rate, outcomes, and complications were evaluated.ResultsThe mean preoperative VAS score was 7.3 and significantly improved to 1.9 postoperatively (at discharge), with a mean improvement rate of 73.3%. With regard to complications, no new fractures of adjacent vertebral bodies were encountered, but cement leakage was seen in 49% of the patients. Most patients were asymptomatic during the postoperative course, although two patients (3%) experienced dyspnea that was suspected to be adult respiratory distress syndrome or a pulmonary embolism.ConclusionPV can offer pain relief to patients with painful vertebral metastases and short life expectancy whose general condition makes surgery difficult.

New vertebral compression fractures after prophylactic vertebroplasty in osteoporotic patients.

OBJECTIVE Previous studies have shown the possible efficacy of prophylactic cement injection for nonfractured vertebrae during percutaneous vertebroplasty for compression fractures. The purpose of this study was to investigate risk factors for subsequent fractures after prophylactic percutaneous vertebroplasty. MATERIALS AND METHODS This retrospective study included 116 patients with osteoporotic compression fractures who underwent prophylactic percutaneous vertebroplasty. The patients were monitored with physical examinations and radiographs at 1 day and at 3 and 12 months after percutaneous vertebroplasty, and if back pain recurred. We analyzed the following multiple covariates to determine whether they were associated with recurrence: age, sex, steroid use, and the preoperative number of unhealed or chronic compression fractures. RESULTS Subsequent fractures in any vertebra occurred within 3 months after the procedure at 26 vertebrae in 21 patients (18.1%), and 36 occurred in 28 patients (24.1%) within 12 months. The occurrence of subsequent fractures within 12 months depended on the preoperative number of unhealed vertebrae: the occurrence rate was 16.9% (11/65) for one vertebra, 27.0% (10/37) for two vertebrae, and 50.0% (7/14) for three or more vertebrae. The incidence of subsequent fractures was significantly higher in patients with three or more fractures than in those with one fracture (p < 0.05). There were no statistically significant differences for the other factors. CONCLUSION Patients with three or more fractures tended to have subsequent fractures, despite undergoing prophylactic percutaneous vertebroplasty. However, there was no increased risk of subsequent fractures related to prophylactic percutaneous vertebroplasty.

Percutaneous Pediculoplasty for Vertebral Hemangioma Involving the Neural Arch: A Case Report

Vertebral hemangiomas occasionally involve the neural arch and they can be symptomatic. We report a case of symptomatic vertebral hemangioma mainly involving the unilateral neural arch which was successfully treated with percutaneous pediculoplasty using a single-needle technique.

Preprocedural MR imaging for percutaneous vertebroplasty: special interest in contrast enhancement.

PurposeThe success of percutaneous vertebroplasty (PVP) depends greatly on preprocedural evaluation of the patients. The purpose of this study was to evaluate the efficacy of preprocedural magnetic resonance imaging (MRI) for the indications of PVP.Materials and methodsA retrospective review of 122 osteoporotic compression fractures in 63 patients who underwent preprocedural gadolinium-enhanced MRI and PVP was performed. Based on the extent of contrast enhancement on preprocedural MRI, each case was classified into one of two groups: group 1, which represented more than 50% of the vertebral body enhanced; and group 2, which represented less than 50% of the vertebral body enhanced. The most enhancing level was evaluated in multilevel PVP sessions. We evaluated the difference of pre- and postprocedural pain scales between groups 1 and 2 using Mann-Whitneys U-test.ResultsThere was a trend toward higher preoperative pain score in group 1, but it was not statistically significant (P = 0.0537). In addition, the postoperative pain score in group 2 was significantly higher than that in group 1 (P = 0.0007). The difference between the pre- and postoperative pain scores was significantly higher in group 1 than in group 2 (P = 0.0001).ConclusionContrast enhancement on MRI indicates a painful lesion and extensive contrast enhancement predicts better pain relief after PVP.

Cytotoxic Lesions of the Corpus Callosum That Show Restricted Diffusion: Mechanisms, Causes, and Manifestations

Cytotoxic lesions of the corpus callosum (CLOCCs) are secondary lesions associated with various entities. CLOCCs have been found in association with drug therapy, malignancy, infection, subarachnoid hemorrhage, metabolic disorders, trauma, and other entities. In all of these conditions, cell-cytokine interactions lead to markedly increased levels of cytokines and extracellular glutamate. Ultimately, this cascade can lead to dysfunction of the callosal neurons and microglia. Cytotoxic edema develops as water becomes trapped in these cells. On diffusion-weighted magnetic resonance (MR) images, CLOCCs manifest as areas of low diffusion. CLOCCs lack enhancement on contrast material-enhanced images, tend to be midline, and are relatively symmetric. The involvement of the corpus callosum typically shows one of three patterns: (a) a small round or oval lesion located in the center of the splenium, (b) a lesion centered in the splenium but extending through the callosal fibers laterally into the adjacent white matter, or (c) a lesion centered posteriorly but extending into the anterior corpus callosum. CLOCCs are frequently but not invariably reversible. Their pathologic mechanisms are discussed, the typical MR imaging findings are described, and typical cases of CLOCCs are presented. Although CLOCCs are nonspecific with regard to the underlying cause, additional imaging findings and the clinical findings can aid in making a specific diagnosis. Radiologists should be familiar with the imaging appearance of CLOCCs to avoid a misdiagnosis of ischemia. When CLOCCs are found, the underlying cause of the lesion should be sought and addressed. ©RSNA, 2017 An earlier incorrect version of this article appeared online. This article was corrected on February 13, 2017.

Contrast-Enhanced MRI for Detecting Intravertebral Cleft Formation: Relation to the Time Since Onset of Vertebral Fracture

OBJECTIVE The purpose of this study was to investigate the advantages of contrast-enhanced MRI (CE-MRI) for detecting intravertebral clefts over unenhanced MRI in relation to the time since onset of vertebral fracture. MATERIALS AND METHODS In this retrospective study, a total of 115 patients (88 women, 27 men; mean age, 77.1 years) who underwent percutaneous vertebroplasty for a single-level compression fracture within 7 days of preprocedural MRI were enrolled. Two radiologists evaluated preprocedural unenhanced MRI (T1-weighted and STIR) and CE-MRI examinations for intravertebral clefts on separate days by consensus. The time from the onset of fracture to MRI was classified into three groups: early phase fractures (< 1 month), late phase fractures (1-3 months), and chronic phase fractures (≥ 3 months). The cement distribution during percutaneous vertebroplasty was used as a reference standard, and detectability of clefts was compared between unenhanced MRI and CE-MRI in relation to the time frame. An analog of the McNemar test was used for analyses. RESULTS There were 104 patients (90.4%) with and 11 patients (9.6%) without a cleft. The sensitivities of unenhanced MRI and CE-MRI, respectively, for detecting clefts were 60.9% and 91.3% for early phase fractures (p = 0.02); 78.6% and 100% for late phase fractures (p = 0.014); and 92.5% and 94.3% for chronic phase fractures (p = 0.3). The specificities were the same for both groups (100% for each time frame). CONCLUSION CE-MRI is more sensitive than unenhanced MRI for detecting intravertebral clefts in patents with benign compression fractures less than 3 months old.