Chun-Chung Lui

Refractures in cemented vertebrae after percutaneous vertebroplasty: a retrospective analysis

Percutaneous vertebroplasty is an efficient procedure to treat pain due to osteoporotic vertebral compression fractures. However, refracture of cemented vertebrae occurs occasionally after vertebroplasty. It is unclear whether such fractures are procedure-related or part of the natural course of osteoporosis. The effect of potentially important covariates on refracture risk in cemented vertebrae has not been evaluated previously. We retrospectively analyzed the incidence and possible causative mechanism of refracture in patients who had received only one vertebroplasty for a single level of vertebral compression fracture. We assessed the following covariates: age, sex, body weight, height, lumbar spine bone mineral density, treated vertebral level, pre-existing untreated vertebral compression fracture, and gas-containing vertebrae before treatment. Surgical variables, including surgical approach, cement injected, and anterior vertebral height restoration, were also analyzed. Anti-osteoporotic treatment after surgery was recorded. Multiple logistic regression analysis was used to determine the relative risk of refractures of cemented vertebrae. Over all, 98 patients were evaluated with a mean follow-up of 26.9xa0±xa012.4 months (range, 7–55xa0months). We identified 62 refractures and the mean loss of anterior vertebral height was 13.3% (range 3.2–40.3%). The greater the anterior vertebral height obtained from vertebroplasty, the greater the risk of refracture occurring (Pxa0<xa00.01). Gas-containing vertebrae were also prone to refracture after the procedure (Pxa0=xa00.01). Anti-osteoporotic treatment was of borderline significance between refractured and non-refractured vertebrae (Pxa0=xa00.07). Only restoration of anterior vertebral height was positively associated with refracture during the follow-ups (Pxa0<xa00.01). In conclusion, refractures of cemented vertebrae after vertebroplasty occurred in 63% of osteoporotic patients. Significant anterior vertebral height restoration increases the risk of subsequent fracture in cemented vertebrae.

New vertebral osteoporotic compression fractures after percutaneous vertebroplasty: retrospective analysis of risk factors.

PURPOSEnTo investigate risk factors for new vertebral compression fractures (VCFs) after vertebroplasty.nnnMATERIALS AND METHODSnThe authors analyzed the occurrence of new VCFs in 70 patients who had previously undergone vertebroplasty for the treatment of one VCF. The following covariates were analyzed: age, sex, body weight, height, body mass index (BMI), treated vertebral level, relative distance between treated vertebrae and new VCFs, pre-existing untreated VCFs, gas-containing vertebrae before treatment, and surgical approach. Surgical variables, including cement leakage into the disk, anterior vertebral height restoration, and kyphosis correction of treated vertebrae were also analyzed. A Cox proportional hazards regression analysis was used to determine the relative risk of new adjacent VCFs. The Kaplan-Meier method was used to calculate mean fracture-free rate over time.nnnRESULTSnSeventy patients were reviewed, with a mean follow-up of 20.0 months +/- 10.2 (range, 6-48 months). We identified 22 new fractures in 19 of the 70 patients (27%), with 16 adjacent and six nonadjacent VCFs. The mean time to new fracture was 10.6 months +/- 9.5, and there was no significant difference in time to adjacent or nonadjacent VCF. Increased risk of VCF was associated with proximity to the treated vertebra, greater kyphosis correction, and low patient BMI. The 1-year fracture-free rate was 79.5%.nnnCONCLUSIONSnNew VCFs are common in patients with a low BMI, which suggests osteoporosis as a mechanism of fracture.

Unusual Presentation of Infected Vertebroplasty with Delayed Cement Dislodgment in an Immunocompromised Patient: Case Report and Review of Literature

Percutaneous vertebroplasty has been established as a safe and effective treatment for compression fractures of osteoporotic vertebrae. Complications of vertebroplasty, such as infection or anterior cement extrusion, are rare. Herein, we report an unusual presentation in an immunocompromised patient with an insidious infection of the disk. This infection resulted in dislodgment of the cement inferiorly and a compression fracture of the adjacent vertebra 6 months after vertebroplasty. We discuss the significance of this case and compare it with 7 others found in the literature.

The impact of preoperative magnetic resonance images on outcome of cemented vertebrae

Refracture of cemented vertebrae is often seen after percutaneous vertebroplasty. The purpose of this prospective study was to evaluate pre-procedural magnetic resonance images (MRI) for the prediction of further collapse and vertebral height loss after vertebroplasty. This study included 81 consecutive patients (73 women and 8 men) with osteoporotic compression fractures. MR studies were performed 1–5xa0days before vertebroplasty. Patients were followed to evaluate refracture for a minimum of 6xa0months after treatment. Cox proportional hazards model was used to evaluate relationships between clinical data, covariates on pre-procedural MRI, and the presence of cemented vertebrae refracture. The mean refracture rate was estimated with the Kaplan–Meier method. After a mean follow-up of 23.0xa0±xa08.2xa0months, 46 cemented vertebrae (57%) experienced refracture, and the mean loss of anterior vertebral height was 11.3%. The 1-year refracture rate after vertebroplasty was 7%, and rapid increased to 76% in the third year. Cox proportional analysis showed that any 1% decrease in signal intensity on T2-weighted images of the injured vertebra will increase the refracture rate by 0.74% (ORxa0=xa00.26, 95% CI 0.08–0.81, pxa0=xa00.02), and a 1% increase in the poorly enhanced volume ratio will increase the refracture rate by 4.3% (ORxa0=xa05.32, 95% CI 1.22–23.14, pxa0=xa00.03). Quantitative pre-procedural MRI appears to be useful in exploring vertebrae with poor bone marrow integrity, which effectively predicts the subsequent refracture of cemented vertebra.

Dynamic contrast-enhanced magnetic resonance imaging for evaluating intraosseous cleft formation in patients with osteoporotic vertebral compression fractures before vertebroplasty.

Study Design. A prospective trial of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in patients with osteoporotic vertebral compression fracture (VCF). Objective. To investigate the relationship between intraosseous clefts and bone marrow perfusion using DCE-MRI in patients with osteoporotic VCF before vertebroplasty. Summary of Background Data. The nonhealing cleft may be responsible for persistent pain and progressive vertebral collapse after acute injury. If localized kyphosis increased, there is risk of neuropathy appearing as a complication. Even after receiving vertebroplasty, it was reported to be at increased risk for subsequent cemented vertebral refracture and new adjacent vertebral fractures. DCE -MRI has been used for the evaluation of bone marrow perfusion. However, there are few reports on the evaluation of osteoporotic VCF and intraosseous cleft formation. Materials. Forty subjects referred for evaluation of VCF underwent DCE-MRI. Bone marrow perfusion, as measured using the DCE-MRI time-intensity curve from a noninjured vertebrae was developed using two distinct parameters including peak enhancement ratio and enhancement slope. The ratio of the well-enhanced and the poorly enhanced zone of each injured vertebra were calculated. Multiple logistic regression analysis was used to evaluate the relationships between baseline clinical factors, parameters of DCE-MRI and presence or absence of intraosseous clefts. Results. Twenty-nine injured vertebrae (72%) had intraosseous clefts. Lower PER of the noninjured vertebrae was associated with higher poorly enhanced zone ratio of the injured vertebrae (&ggr; = −0.362, P = 0.017). Multivariate logistic regression analysis identified only lower PER (hazard ratio, 0.000; 95% confidence interval, 0.000–0.096; P = 0.009) was associated with the presence of intraosseous clefts. A peak enhancement ratio value less than 0.57 had a sensitivity of 80% and specificity of 90% for predicting intraosseous clefts. Conclusion. In patients with osteoporotic VCF before vertebroplasty, decreased bone marrow perfusion, as measured by DCE-MRI, was associated with intraosseous cleft formation.

Effect of TheraCyte-encapsulated parathyroid cells on lumbar fusion in a rat model

IntroductionImplantation of TheraCyte 4xa0×xa0106 live parathyroid cells can increase the bone marrow density of the spine of ovariectomized rats. There has been no published study examining the effect of such implantation on spinal fusion outcomes. The purpose of this study was to examine the effect of TheraCyte-encapsulated parathyroid cells on posterolateral lumbar fusions in a rat model.Materials and methods Forty Sprague-Dawley rats underwent single-level, intertransverse process spinal fusions using iliac crest autograft. The rats were randomly assigned to two groups: Group 1 rats received sham operations on their necks (control; Nxa0=xa020); Group 2 rats were implanted with TheraCyte-encapsulated 4xa0×xa0106 live parathyroid cells into the subcutis of their necks (TheraCyte; Nxa0=xa020). Six weeks after surgery the rats were killed. Fusion was assessed by inspection, manual palpation, radiography, and histology. Blood was drawn to measure the serum levels of calcium, phosphorus, and intact parathyroid hormone (iPTH).Results Based on manual palpation, the control group had a fusion rate of 33xa0% (6/18) and the TheraCyte group had a fusion rate of 72xa0% (13/18) (Pxa0=xa00.044). Histology confirmed the manual palpation results. Serum iPTH levels were significantly higher in the TheraCyte group compared with the control group (Pxa0<xa00.05); neither serum calcium nor phosphorus levels were significantly different between the two groups.Discussion This pilot animal study revealed that there were more fusions in rats that received TheraCyte-encapsulated 4xa0×xa0106 live parathyroid cells than in control rats without significant change in serum calcium or phosphorus concentrations. As with any animal study, the results may not extrapolate to a higher species. Further studies are needed to determine if these effects are clinically significant.

Unusual femoral artery mycotic aneurysm complicated by infective spondylitis

We present a patient who experienced an aortic aneurysm and a left femoral artery mycotic aneurysm, which resulted from L4-infective spondylitis via the iliopsoas compartment. This rare complication could be underdiagnosed in the absence of a more extended field of imaging view such as is provided by computed tomography.

Can antiosteoporotic therapy reduce mortality in MRI-proved acute osteoporotic vertebral fractures?

Patients with MRI-proved acute painful vertebral fractures in whom conservative pain management fails are frequently referred for vertebroplasty. This study investigated the effects of treating osteoporosis on the mortality rate of patients with MRI-proved acute osteoporosis-related vertebral fractures who had undergone vertebroplasty. We retrospectively reviewed the cases of osteoporosis patients with MRI-proved acute vertebral fractures who had been treated with vertebroplasty from January 2001 to December 2007. The long-term outcomes of the patients who received antiosteoporotic therapy were compared with those of patients who received no therapy. A total of 304 patients (247 female patients and 57 male patients; mean age, 74.1xa0±xa07.7xa0years) were enrolled in the study. The patients who received antiosteoporotic therapy had a significantly lower mortality rate than did patients who did not receive antiosteoporotic therapy (Pxa0=xa00.001; hazard ratio,xa00.396, 95xa0% confidence interval, 0.273–0.575). At the end of the study, 183 patients were alive, and 121 had died. Effective treatment for osteoporosis may improve survival in patients with osteoporosis-related vertebral fractures after vertebroplasty.

Is raloxifene associated with lower risk of mortality in postmenopausal women with vertebral fractures after vertebroplasty?: a hospital-based analysis

BackgroundOsteoporotic fractures are associated with mortality in postmenopausal woman. Whether raloxifen treatment after vertebroplasty can reduce mortality is unclear in this group. To compare the effect of raloxifene and no osteoporosis treatment on the risk of mortality after vertebroplasty, we designed this study.MethodsThis was a retrospective study (January 2001 to December 2007). Follow-up for each participant was calculated as the time from inclusion in the study to the time of death, or to December 31st, 2013, whichever occurred first. All of the patients underwent baseline bone density studies, and age and body mass index (kg/m2) were recorded. All associated medical diseases such as diabetes, hypertension, and liver and renal disease were recorded.ResultsOne hundred and forty-nine patients with vertebral fractures were enrolled, of whom 51 used raloxifene and 98 patients did not receive any anti-osteoporotic therapy. At the end of the follow-up period, 62 patients had died and 87 were still alive. The treated patients had a lower mortality rate than those who did not receive treatment (Pu2009=u20090.001, HRu2009=u20093.845, 95xa0% CI 1.884-7.845). The most common cause of mortality was sepsis, and those who received raloxifene had a lower rate of sepsis compared to those who did not receive treatment (Pu2009<u20090.001).ConclusionsEffective treatment with raloxifene may had a lower mortality rate in patients with postmenopausal osteoporosis-related vertebral fractures after vertebroplasty.

Application of Cine Phase Contrast MRI in Spontaneous Intracranial Hypotension Before and After Treatment

Spontaneous intracranial hypotension (SIH) is characterized by orthostatic headache. Typical abnormal magnetic resonance imaging (MRI) findings have been considered to be the sine qua non of SIH, but a sizeable minority of patients has normal results using conventional MRI. The purpose of this study was to evaluate the difference in cerebrospinal fluid (CSF) flow dynamics between patients and healthy people using cine phase contrast (PC) MRI, and to assess the CSF flow dynamics in patients before and after treatment. From November of 2007 to December of 2012, twenty patients with SIH (10 men and 10 women, mean age=40.9±7.77 years) and 31 age- and gender- matched healthy subjects (15 men and 16 women, mean age=46.3±7.53 years) were enrolled in this retrospective study. Cine PC MRI was performed on the patients and on the healthy subjects to measure the CSF flow in cerebral aqueduct. Patients underwent repeated cine PC MRI at 24 hours and at one month after treatment respectively. Five parameters including peak positive and negative velocity, average flow, and average positive and negative flow were recorded to evaluate their differences. Seventeen patients (85%) received epidural blood patching (EBP) owing to the failure of conservative treatment. All patients experienced resolution of symptoms after treatment. Before treatment, the patients had a significantly lower average CSF flow than the healthy subjects (p＜0.001). The average CSF flow was elevated in patients with SIH at 24 hours after treatment and was significantly increased one month after treatment (p=0.003). By establishment of the receiver operating characteristic (ROC) curve, the best cutoff value for the average CSF flow was determined to be 14.0μl/beat, while the sensitivity and specificity were determined to be 90.3% and 72.2%, respectively. Patients with SIH showed lower CSF flow compared to healthy subjects, but this decreased CSF flow was shown by cine PC MRI to be gradually recovered after treatment. This study provides evidence that cine PC MRI is useful for assessing the dynamic changes of CSF flow in the cerebral aqueduct noninvasively and for demonstrating the effectiveness of treatment in patients with SIH reliably.