Immunological regulation and the role of autophagy in preeclampsia.

Autophagy is a bulk degradation system that maintains cellular homeostasis by producing energy and/or recycling excess proteins. During early placentation, extravillous trophoblasts invade the decidua and uterine myometrium, facing maternal immune cells, which participate in the immune suppression of paternal and fetal antigens. Regulatory T cells will likely increase in response to a specific antigen before and during early pregnancy. Insufficient expansion of antigen-specific Treg cells, which possess the same T cell receptor, is associated with the pathophysiology of preeclampsia, suggesting sterile systemic inflammation. Autophagy is involved in reducing inflammation through the degradation of inflammasomes and in the differentiation and function of regulatory T cells. Autophagy dysregulation induces protein aggregation in trophoblasts, resulting in placental dysfunction. In this review, we discuss the role of regulatory T cells in normal pregnancies. In addition, we discuss the association between autophagy and regulatory T cells in the development of preeclampsia based on reports on the role of autophagy in autoimmune diseases.

Short-segment spinal fusion for chronic low back pain with bone marrow edema adjacent to the vertebral endplate in adult spinal deformity.

PURPOSE: Corrective long spinal fusion is a widely accepted surgical method for patients with adult spinal deformities. However, instrumented long fusion is associated with a significant risk of complications. Therefore, we aimed to assess the success of short-segment spinal fusion, particularly for bone marrow edema (BME) adjacent to the vertebral endplate, in patients with low back pain (LBP) and spinal deformity. METHODS: A prospective study was performed at multiple hospitals wherein we monitored patients with spinal deformities and accompanying LBP. Patients aged ≥ 50 years with a minimum LBP severity score of 40 mm on the visual analog scale (VAS) were included in the study. We also included patients with lumbar BME on magnetic resonance imaging. Short spinal fusion was performed on segments with BME. Clinical evaluations of LBP on VAS and Oswestry Disability Index (ODI), and radiological parameters for sagittal vertical axis (SVA), pelvic incidence (PI), lumbar lordosis (LL) and pelvic tilt (PT) were carried out. RESULTS: Overall, 35 patients (22 men and 13 women), with a mean age of 66.7 years and a mean follow-up period of 32 months, were included in the study. The mean VAS and ODI scores were 72.4 mm and 49.0% before surgery and 25.5 mm and 29.9% at the final follow-up, respectively; these parameters significantly improved after surgery. The SVA, PI-LL, and PT scores were 70.1 mm, 20.9°, and 22.8° before surgery and 85.4 mm, 13.8°, and 22.7° at the final follow-up, respectively. The spinal alignment parameters did not change significantly after surgery. CONCLUSIONS: Short-segment spinal fusion is effective for treating LBP and spinal deformity with BME adjacent to the vertebral endplate without spinal correction.

Balancing ability of patients with lumbar spinal canal stenosis.

PURPOSE: To determine the relationship between postural sway and the severity of lumbar spinal canal stenosis as well as the effect on postoperative improvement. METHODS: Stabilometry was performed before and 6 months after surgery in 52 patients (29 men and 23 women; mean age, 74.1 ± 7.8 years) who underwent decompression surgery for lumbar spinal canal stenosis. The environmental area (EA; the area surrounding the circumference of the stabilogram) and locus length per EA (L/EA) were evaluated. The patients were divided into moderate (n = 22) and severe (n = 30) groups according to the severity of canal stenosis. Patient characteristics and parameters were compared between the groups before and after surgery, including the visual analog scale (VAS) score for leg pain, Oswestry Disability Index (ODI), EA, and L/EA. In addition, factors affecting EA and L/EA were evaluated using multiple regression analysis. RESULTS: Age (p = 0.031), preoperative EA (p < 0.001), preoperative L/EA (p = 0.032), and sagittal vertical axis (p = 0.033) were significantly different between groups. The VAS score and ODI significantly improved postoperatively in both groups (p < 0.001). The EA significantly improved postoperatively only in the severe group (p < 0.001), whereas the L/EA did not significantly improve in either group. Multiple regression analysis showed that only the severity of canal stenosis was significantly associated with preoperative EA (p = 0.030), whereas age (p = 0.040) and severity of canal stenosis (p = 0.030) were significantly associated with preoperative L/EA. Diabetes was significantly associated with postoperative EA (p = 0.046) and L/EA (p = 0.030). CONCLUSION: The severity of canal stenosis affected abnormal postural sway, which improved after decompression surgery.

Prognostic factors of balloon kyphoplasty for osteoporotic vertebral fractures with diffuse idiopathic skeletal hyperostosis.

OBJECTIVE: The authors aimed to determine the poor prognostic factors of balloon kyphoplasty for the treatment of fractures of the most distal or distal-adjacent vertebrae in ankylosing spines with diffuse idiopathic skeletal hyperostosis (DISH). METHODS: Eighty-nine patients with fractures of the most distal or distal-adjacent vertebrae of ankylosing spines with DISH were included and divided into two groups: those with (n = 51) and without (n = 38) bone healing 6 months postoperatively. Clinical evaluation included age, sex, time from onset to surgery, the visual analog scale score for low-back pain, and the Oswestry Disability Index (ODI). The VAS scores and ODI were measured both preoperatively and at 6 months postoperatively. Radiological evaluations included bone density; wedge angles of the fractured vertebrae in the supine and sitting positions on lateral radiographs; differences in the wedge angles (change in wedge angle); and the amount of polymethylmethacrylate used. RESULTS: The preoperative ODI, vertebral wedge angles in the supine and sitting positions, change in wedge angle, and amount of polymethylmethacrylate were significantly different between the two groups and were significantly associated with delayed bone healing in univariate logistic regression analysis. Multivariate logistic regression analysis showed that only a change in the wedge angle was significantly associated with delayed healing, with a cutoff value of 10°, sensitivity of 84.2%, and specificity of 82.4%. CONCLUSIONS: Treatment with balloon kyphoplasty alone should be avoided in patients with a difference ≥ 10° in the wedge angle of the fractured vertebrae between the supine and sitting positions.

The Role of Autophagy in the Female Reproduction System: For Beginners to Experts in This Field.

Autophagy is a fundamental process involved in regulating cellular homeostasis. Autophagy has been classically discovered as a cellular process that degrades cytoplasmic components non-selectively to produce energy. Over the past few decades, this process has been shown to work in energy production, as well as in the reduction of excessive proteins, damaged organelles, and membrane trafficking. It contributes to many human diseases, such as neurodegenerative diseases, carcinogenesis, diabetes mellitus, development, longevity, and reproduction. In this review, we provide important information for interpreting results related to autophagic experiments and present the role of autophagy in this field.

Chloroquine is a safe autophagy inhibitor for sustaining the expression of antioxidant enzymes in trophoblasts.

Inhibition of autophagy contributes to the pathophysiology of preeclampsia. Although chloroquine (CHQ) is an autophagy inhibitor, it can reduce the occurrence of preeclampsia in women with systemic lupus erythematosus. To clarify this important clinical question, this study aimed to address the safety of CHQ in trophoblast cells from the viewpoint of homeostasis, in which the anti-oxidative stress (OS) response and autophagy are involved. We used Western blotting to evaluate the protein levels in the trophoblast cells. The expression levels of heme oxygenase-1 (HO-1), an anti-OS enzyme, mediate resistance to OS induced by hydrogen peroxide (H2O2) in trophoblast cell lines. Among the autophagy modulators, bafilomycin A1 (BAF), an autophagy inhibitor, but not autophagy activators, suppressed HO-1 expression in BeWo cells; CHQ did not suppress HO-1 expression in BeWo cells. To clarify the role of autophagy in HO-1 induction, we observed no difference in HO-1 induction by H2O2 between autophagy-normal and autophagy-deficient cells. As for the mechanism of HO-1 induction by OS, BAF suppressed HO-1 induction by downregulating the expression of neighbor of BRCA1 gene 1 (NBR1) in the selective p62-NBR1-nuclear factor erythroid 2-related factor 2 (Nrf2) autophagy pathway. CHQ did not inhibit HO-1 expression by sustaining NBR1 expression in human villous tissues compared to BAF treatment. In conclusion, CHQ is a safer medicine than BAF for sustaining NBR1, which resist against OS in trophoblasts by connecting selective autophagy and the anti-OS response.

Percutaneous Intervertebral-Vacuum Polymethylmethacrylate Injection for Foraminal Stenosis with Degenerative Lumbar Scoliosis.

BACKGROUND: Percutaneous intervertebral-vacuum polymethylmethacrylate injection (PIPI) is a minimally invasive procedure for low back pain in elderly patients with degenerative lumbar scoliosis (DLS). Patients with DLS often have radiculopathy as a result of foraminal stenosis in addition to low back pain. The purpose of this study was to evaluate the clinical and radiologic results of PIPI for foraminal stenosis with radiculopathy in elderly patients with DLS. METHODS: We included patients with de novo DLS aged 65 years or older who underwent PIPI. The presence of an intervertebral vacuum on computed tomography and bone marrow edema on magnetic resonance imaging was required for inclusion. The intersegmental radiologic parameters on plain radiographs and computed tomography and the extent of bone marrow edema on magnetic resonance imaging were measured. The clinical outcomes were evaluated using the visual analog scale (VAS) and Oswestry Disability Index (ODI). RESULTS: We enrolled 40 patients with DLS who underwent PIPI. There were 16 men and 24 women, and the mean age was 79.0 ± 6.3 years. The mean foraminal height and extent of bone marrow edema showed a significant increase and reduction, respectively, after PIPI (P < 0.05). VAS score for radiculopathy and ODI significantly improved after PIPI (P < 0.01). The minimum clinically important differences in VAS score for radiculopathy and ODI at the final follow-up were 73.9% and 63.6%, respectively. CONCLUSIONS: PIPI is a minimally invasive procedure not only for low back pain but also for radiculopathy in elderly patients with DLS. It leads to intervertebral stabilization and indirect decompression of the foramen.

Spinous Process Fractures in Osteoporotic Vertebral Fractures: A Cross-Sectional Study.

Introduction: The purpose of this study was to assess radiological features and clinical scores of osteoporotic vertebral fracture (OVF) accompanied by spinous process fracture (SPF). Methods: We included painful patients with single-level OVF with intravertebral cleft. SPF was detected using magnetic resonance imaging (MRI) and/or computed tomography (CT). The plain radiographs of the vertebral fractures were evaluated based on the wedging angle of the fractured vertebrae and vertebral instability. We investigated the clinical parameters of age, gender, visual analog scale (VAS) score for low back pain (LBP), Oswestry Disability Index (ODI), and the period from the onset of acute fracture. Results: MRI and/or CT indicated among 195 patients of OVF with LBP, 41 patients (20.5%) had SPFs. SPFs were observed one level above the fractured vertebral body in 35 patients (85.4%) and at the same level as the fractured vertebral body in 6 patients (14.6%). The prevalence of vertebral fracture of thoracic spine in the SPF-positive group was significantly greater than that in the SPF-negative group. There were no significant differences in age, gender, VAS, ODI, the time period from the onset of acute LBP, wedging angle, and vertebral instability between the presence or absence of SPFs. Conclusions: SPFs occurred in 20.5% of patients with OVF and LBP. In addition, SPFs often occurred one level above the fractured vertebra, and SPFs with OVF tended to be located in the thoracic spine.

Radiographic Factors for Adjacent Vertebral Fractures and Cement Loosening Following Balloon Kyphoplasty in Patients with Osteoporotic Vertebral Fractures.

Introduction: Balloon kyphoplasty (BKP) is a minimally invasive surgical approach for the treatment of osteoporotic vertebral fractures (OVF). Some risks have been reported after treatment with BKP; therefore, it is necessary to determine when BKP does not work. Thus, in this study, we aim to clarify the radiographic predictors of secondary vertebral fractures and cement loosening after BKP for OVF. Methods: This study enrolled patients with single-level OVF at the thoracolumbar junction (T11-L2) who underwent BKP for the first time between January 2011 and March 2014. The clinical outcomes were evaluated using the visual analog scale (VAS) and a modified Oswestry Disability Index (ODI) at 1 week and 1, 3, 6, and 12 months after surgery. Radiographic assessments were performed preoperatively and within 1 year after BKP using plain radiography and computed tomography. Results: The 85 patients who met the inclusion criteria underwent BKP. The average age of participants (21 men, 64 women) was 77.8 years (range, 57-92 years). Postoperative VAS and ODI scores were all significantly better than preoperative scores. Polymethyl methacrylate (PMMA)-cement leakage was observed in 18 patients (21.2%) but was asymptomatic in all cases. Secondary vertebral fractures were detected in 20 patients (23.5%), including adjacent levels in 15 patients (17.6%) and non-adjacent levels in 5 patients (5.9%). Rostral bridging osteophyte formation was found to be significantly associated with the occurrence of adjacent vertebral fractures (odds ratio 12.746; p=0.010). PMMA-cement loosening was observed in three patients (3.5%). A high prevalence (100%) of bridging osteophytes, vacuum clefts, and spinous process fractures was observed in patients with PMMA-cement loosening. PMMA-cement loosening was found in 3 out of 10 patients with all three of these factors. Conclusions: Rostral bridging osteophyte formation was determined to be a risk factor for both adjacent vertebral fractures and PMMA-cement loosening.Level of Evidence: 3.

Quantifying Bone Marrow Edema Adjacent to the Lumbar Vertebral Endplate on Magnetic Resonance Imaging: A Cross-Sectional Study of Patients with Degenerative Lumbar Disease.

STUDY DESIGN: Cross-sectional study. PURPOSE: We aimed to quantitatively assess bone marrow edema (BME) on magnetic resonance imaging (MRI) for patients with degenerative lumbar diseases. OVERVIEW OF LITERATURE: BME adjacent to a sclerotic endplate of the lumbar spine, detected using T2-weighted fat-saturated MRI, is closely associated with low back pain in patients with degenerative lumbar diseases. However, currently, there no quantitative evaluation methods for BME adjacent to the vertebral endplate. METHODS: Patients with degenerative lumbar diseases, whose MRIs detected BME, were enrolled. On a T2-weighted fat-saturated MRI, BME appeared as a high-intensity region adjacent to the vertebral endplate. We calculated the contrast ratios (CRs) of BME and normal bone marrow using the signal intensities of BME, normal bone marrow, and the spinal cord. On computed tomography, we calculated Hounsfield unit (HU) values in the same area as BME, the sclerotic endplate, and normal bone marrow to assess bone density. RESULTS: There were 16 men and 14 women, with an average age of 73.5 years. The mean CRs of BME and normal bone marrow were -0.015±0.056 and -0.407±0.023, respectively. BME's CR was significantly higher than that of normal bone marrow (p<0.01). The HU values in the same area as BME, the sclerotic endplate, and normal bone marrow were 251.9±24.6, 828.3±35.6, and 98.1±9.3, respectively; these values were significantly different from each other (p<0.01). CONCLUSIONS: The CR on MRI is a useful quantitative assessment tool for BME in patients with degenerative lumbar diseases.

Surgical outcomes of cervical myelopathy in patients with athetoid cerebral palsy.

PURPOSE: Surgical treatment for cervical myelopathy with athetoid cerebral palsy remains unestablished. Instrumented fusion is reported to have good clinical results; however, there are no data of decompression surgery for this pathology in recent years. This study aimed to assess the surgical outcomes of laminoplasty with or without posterior instrumented fusion for cervical myelopathy in patients with athetoid cerebral palsy. METHODS: A multi-centre surgical series of patients with cervical myelopathy and athetoid cerebral palsy were enrolled in this study. All patients showed symptoms and signs suggestive of cervical myelopathy and underwent laminoplasty with or without instrumented fusion. The Japanese Orthopaedic Association (JOA) score, Barthel index (BI), and changes in the C2-C7 sagittal Cobb angle in the lateral plain radiograph were analysed. RESULTS: There were 25 patients (16 men and 9 women; mean age, 54.4 ± 10.8 years) with cervical myelopathy and athetoid cerebral palsy who underwent surgical treatment. The mean follow-up period was 41.9 ± 35.6 months. Overall, the BI significantly improved after surgery, whereas the JOA score and C2-C7 angle did not improve postoperatively. The recovery rate of the JOA score in the laminoplasty group was significantly higher than that of the fusion group (P = 0.02). CONCLUSIONS: Cervical laminoplasty with or without instrumented fusion for treating cervical myelopathy due to athetoid cerebral palsy is effective in improving activities of daily living. Cervical laminoplasty may be an effective and less invasive surgical method for selective patients, especially for those with small involuntary movements and no remarkable cervical kyphosis nor instability.

Quantitative evaluation of abnormal finger movements in myelopathy hand during the grip and release test using gyro sensors.

Previous studies have reported qualitative characteristics of myelopathy hand, but few studies have reported quantitative kinematic parameters of this condition. Our purpose of this study was to quantitatively evaluate the abnormal finger movements in patients with cervical compressive myelopathy (CCM) (termed myelopathy hand) and to understand the characteristics of myelopathy hand during the grip and release test (GRT) using gyro sensors. Sixty patients with CCM (severe: n = 30; mild-to-moderate: n = 30) and sixty healthy adults (age-matched control: n = 30; young control: n = 30) were included in this study. All participants performed the GRT. The index and little fingers' and the wrist's movements during the GRT were recorded using three gyro sensors. The number of cycles, switching time-delay, time per cycle, and peak angular velocity were calculated and compared between groups. Patients with severe CCM had the lowest number of cycles and longest switching time-delays, followed by patients with mild-to-moderate CCM, the age-matched control group, and the young control group. The time per cycle and the peak angular velocities of fingers in participants with severe CCM were significantly lower than those in participants with mild-to-moderate CCM; however, there were no significant differences between the control groups. The peak angular velocities of fingers were significantly lower during extension motions than during flexion motions in participants with CCM. Participants with CCM have lower peak angular velocities during finger movement. Finger extension also is impaired in participants with CCM. Abnormal finger movements and the severity of myelopathy in participants with CCM can be assessed using gyro sensors.

Long-term outcome of targeted therapy for low back pain in elderly degenerative lumbar scoliosis.

PURPOSE: Treatment of low back pain (LBP) associated with elderly degenerative lumbar scoliosis (DLS) remains controversial. We have developed percutaneous intervertebral-vacuum polymethylmethacrylate injection (PIPI) targeting to the intervertebral vacuum as a minimally invasive surgery. The present study compared the long-term clinical outcomes of PIPI to that of nonoperative treatment. METHODS: Patients with de novo DLS, aged ≥ 65 years, who had LBP with visual analog scale (VAS) of ≥ 50 for ≥ 6 months with intervertebral vacuum on computed tomography and bone marrow edema (BME) on magnetic resonance imaging were included. The clinical outcomes were evaluated using VAS and the Oswestry Disability Index (ODI) at baseline, 1, 6, 12, 24 months, and at the final follow-up. The course of BME was also evaluated. RESULTS: One hundred and one patients underwent PIPI and 61 received nonoperative treatment. The mean follow-up duration after PIPI and nonoperative treatment was 63.7 ± 32.4 and 43.9 ± 20.9 months, respectively. VAS and ODI after PIPI were significantly improved compared to post-nonoperative treatment. BME decreased substantially in the PIPI group and it was significantly correlated with VAS and ODI improvement. Following PIPI, LBP recurred in 28 patients (35%). LBP recurrence was identified at the same level of PIPI in 10 patients, at the adjacent level of PIPI in 11 patients, and at the non-adjacent level of PIPI in seven patients. Eighteen patients underwent additional PIPIs, and both VAS and ODI were significantly improved after additional PIPIs. CONCLUSION: Bone marrow lesions of the endplate are strongly associated with the presence of LBP. PIPI can be considered as an effective, safe and repeatable treatment for LBP in elderly DLS patients.

Prostaglandin E2-EP4 Axis Promotes Lipolysis and Fibrosis in Adipose Tissue Leading to Ectopic Fat Deposition and Insulin Resistance.

Lipolysis, the breakdown of triglyceride storage in white adipose tissue, supplies fatty acids to other tissues as a fuel under fasting conditions. In morbid obesity, fibrosis limits adipocyte expandability, resulting in enforced lipolysis, ectopic fat distribution, and ultimately insulin resistance. Although basal levels of lipolysis persist even after feeding, the regulatory mechanisms of basal lipolysis remain unclear. Here, we show the important role of adipocyte prostaglandin (PG) E2-EP4 receptor signaling in controlling basal lipolysis, fat distribution, and collagen deposition during feeding-fasting cycles. The PGE2-synthesis pathway in adipocytes, which is coupled with lipolysis, is activated by insulin during feeding. By regulating the lipolytic key players, the PGE2-EP4 pathway sustains basal lipolysis as a negative feedback loop of insulin action, and perturbation of this process leads to "metabolically healthy obesity." The potential role of the human EP4 receptor in lipid regulation was also suggested through genotype-phenotype association analyses.

Synovitis, Acne, Pustulosis, Hyperostosis, and Osteitis (SAPHO) Syndrome with Destructive Spondylitis: A Case Report.

INTRODUCTION: Spinal lesions in synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome generally have a good prognosis and rarely cause structural destruction or neurological deterioration. We described a surgical case of posterior instrumented surgery without anterior reconstruction and bone graft in a patient with SAPHO syndrome with destructive spondylitis and reviewed the literature on surgical treatment for this entity. CASE REPORT: We describe the case of a 73-year-old male who presented with palmoplantar pustulosis. He experienced progressive low back and leg pain for the past 3 months. Destructive spondylitis and lumbar canal stenosis were detected with magnetic resonance imaging (MRI), and aspiration biopsy was used to exclude pyogenic spondylitis and spinal tumors. He underwent posterior decompression and fixation surgery without anterior reconstruction and bone grafting. Low back and leg pain improved after surgery. Postoperative radiography and computed tomography showed boney bridge between vertebral bodies, and MRI showed the decrease of bone marrow edema. CONCLUSIONS: Posterior fusion without anterior reconstruction produced a bony bridge between the vertebral bodies. Taking the pathophysiology of SAPHO syndrome into consideration, anterior reconstructed fusion for patients with SAPHO syndrome might not be needed.

Transforaminal percutaneous endoscopic discectomy for lumbar disc herniation in athletes under the local anesthesia.

BACKGROUND: Percutaneous endoscopic discectomy (PED) has been reported to be less invasive and effective procedure for lumbar disc herniation (LDH). Damage to the back muscle is considered minimal, which is particularly important for athletes. However, the results of PED for LDH in athletes have not been reported well. The purpose of this study was to evaluate the clinical outcomes of PED for LDH in athletes. METHODS: We retrospectively analyzed 21 athlete patients with LDH who had undergone PED. All patients received athletic rehabilitation immediately after surgery. The clinical outcomes were evaluated from the visual analogue scale (VAS) for leg pain and low back pain (LBP), the Oswestry Disability Index (ODI), complications and periods of return to sport. RESULTS: There were 18 men and 3 women, and the mean age at the time of surgery was 22.9 years (range: 15-43 years). The mean VAS scores for leg pain before and after surgery were 64.3 ± 2.7 mm and 12.4 ± 1.4 mm, respectively. The mean VAS scores for LBP before and after surgery were 62.1 ± 2.2 mm and 10.5 ± 1.1 mm, respectively. The mean ODI scores before and after surgery were 31.3 ± 14.0% and 14.6 ± 7.1%, respectively. The VAS for leg pain, as well as the LBP and ODI, significantly improved after surgery. There were no complications related to the surgery. Ninety-five percent (20/21) returned to play sports at the same performance level as before the procedure by an average of 9.2 weeks after PED. CONCLUSIONS: PED is a minimally invasive and effective procedure for patients with LDH, especially in athletes. Not only the patients' leg pain but also their discogenic LBP improved. PED has the benefits of preservation of normal posterior structures and a faster return to sports.

Risk Factors for Cement Loosening after Vertebroplasty for Osteoporotic Vertebral Fracture with Intravertebral Cleft: A Retrospective Analysis.

STUDY DESIGN: Retrospective case-control study. PURPOSE: To evaluate the primary outcomes and radiographic results of percutaneous vertebroplasty (PVP) in patients with singlelevel osteoporotic vertebral fracture (OVF) with intravertebral cleft (IVC) to identify the risk factors for cement loosening after PVP. OVERVIEW OF LITERATURE: PVP is a widely accepted method for managing painful OVF; however, cement loosening occasionally occurs with poor outcomes. METHODS: This retrospective study involved 195 patients treated with PVP for single-level OVF with IVC. Six months thereafter, the primary outcomes were evaluated using the Visual Analog Scale (VAS) for back pain and the modified Oswestry Disability Index. Computed tomography was conducted to detect cement loosening. Possible risk factors, such as age, sex, wedging angle, intravertebral instability, Parkinson's disease, spinous process fracture, ankylosing spinal hyperostosis, split vertebrae, and adjacent intervertebral vacuum, were assessed. RESULTS: Forty-nine patients (25%) experienced cement loosening 6 months after PVP. The mean VAS scores were significantly higher in patients with cement loosening than in those without (50 vs. 26 mm, respectively; p <0.01). Cement loosening was closely associated with intravertebral instability (odds ratio [OR], 1.20; 95% confidence interval [CI], 1.04-1.40; p =0.015), Parkinson's disease (OR, 54.31; 95% CI, 4.47-659.53; p =0.002), spinous process fracture (OR, 7.11; 95% CI, 1.65-30.60; p =0.009), and split vertebrae (OR, 11.59; 95% CI, 1.64-82.02; p =0.014). CONCLUSIONS: Patients with cement loosening experienced worse back pain than those without cement loosening. The important risk factors that influenced cement loosening after PVP were high intravertebral instability, Parkinson's disease, spinous process fracture, and split vertebrae.