Mortality among older adults with osteoporotic vertebral fracture.

We evaluated whether older adults who received kyphoplasty had reduced risk of mortality compared to those who did not. In unmatched analyses, those receiving kyphoplasty were at reduced risk of death but after matching on age and medical complications, patients who received kyphoplasty were at increased risk of death. PURPOSE: In previous observational studies, kyphoplasty for treatment of osteoporotic vertebral fractures has been associated with decreased mortality compared to conservative management. The purpose of this research was to determine whether older adults who received kyphoplasty had reduced risk of mortality compared to matched patients who did not. METHODS: Retrospective cohort study of US Medicare enrollees with osteoporotic vertebral fractures between 2017-2019 comparing patients who underwent kyphoplasty to those who did not. We identified 2 control groups a priori: 1) non-augmented patients who met inclusion criteria (group 1); 2) propensity-matched patients on demographic and clinical variables (group 2). We then identified additional control groups using matching for medical complications (group 3) and age + comorbidities (group 4). We calculated hazard ratios (HRs) and 95% confidence intervals (95% CIs) associated with mortality. RESULTS: A total of 235,317 patients (mean (± standard deviation) age 81.1 ± 8.3 years; 85.8% female) were analyzed. In the primary analyses, those who received kyphoplasty were at reduced risk of death compared to those who did not: adjusted HR (95% CI) in group 1 = 0.84 (0.82, 0.87); and in group 2 = 0.88 (0.85, 0.91). However, in post hoc analyses, patients who received kyphoplasty were at increased risk of death: adjusted HR (95% CI) in group 3 = 1.32 (1.25, 1.41) and 1.81 (1.58, 2.09) in group 4. CONCLUSION: An apparent benefit of kyphoplasty on mortality among patients with vertebral fractures was not present after rigorous propensity matching, illustrating the importance of comparing similar individuals when evaluating observational data.

Development and Assessment of a Predictive Score for Vertebral Compression Fracture After Stereotactic Body Radiation Therapy for Spinal Metastases.

IMPORTANCE: Vertebral compression fracture (VCF) is a potential adverse effect following treatment with stereotactic body radiation therapy (SBRT) for spinal metastases. OBJECTIVE: To develop and assess a risk stratification model for VCF after SBRT. DESIGN, SETTING, AND PARTICIPANTS: This retrospective cohort study conducted at a high-volume referral center included 331 patients who had undergone 464 spine SBRT treatments from December 2007 through October 2019. Data analysis was conducted from November 1, 2020, to August 17, 2021. Exclusions included proton therapy, prior surgical intervention, vertebroplasty, or missing data. EXPOSURES: One and 3 fraction spine SBRT treatments were most commonly delivered. Single-fraction treatments generally involved prescribed doses of 16 to 24 Gy (median, 20 Gy; range, 16-30 Gy) to gross disease compared with multifraction treatment that delivered a median of 30 Gy (range, 21-50 Gy). MAIN OUTCOMES AND MEASURES: The VCF and radiography components of the spinal instability neoplastic score were determined by a radiologist. Recursive partitioning analysis was conducted using separate training (70%), internal validation (15%), and test (15%) sets. The log-rank test was the criterion for node splitting. RESULTS: Of the 331 participants, 88 were women (27%), and the mean (IQR) age was 63 (59-72) years. With a median follow-up of 21 months (IQR, 11-39 months), we identified 84 VCFs (18%), including 65 (77%) de novo and 19 (23%) progressive fractures. There was a median of 9 months (IQR, 3-21 months) to developing a VCF. From 15 candidate variables, 6 were identified using the backward selection method, feature importance testing, and a correlation heatmap. Four were selected via recursive partitioning analysis: epidural tumor extension, lumbar location, gross tumor volume of more than 10 cc, and a spinal instability neoplastic score of more than 6. One point was assigned to each variable, and the resulting multivariable Cox model had a concordance of 0.760. The hazard ratio per 1-point increase for VCF was 1.93 (95% CI, 1.62-2.30; P < .001). The cumulative incidence of VCF at 2 years (with death as a competing risk) was 6.7% (95% CI, 4.2%-10.7%) for low-risk (score, 0-1; 273 [58.3%]), 17.0% (95% CI, 10.8%-26.7%) for intermediate-risk (score, 2; 99 [21.3%]), and 35.4% (95% CI, 26.7%-46.9%) for high-risk cases (score, 3-4; 92 [19.8%]) (P < .001). Similar results were observed for freedom from VCF using stratification. CONCLUSIONS AND RELEVANCE: The results of this cohort study identify a subgroup of patients with high risk for VCF following treatment with SBRT who may potentially benefit from undergoing prophylactic spinal stabilization or vertebroplasty.

Resources utilisation and economic burden of percutaneous vertebroplasty or percutaneous kyphoplasty for treatment of osteoporotic vertebral compression fractures in China: a retrospective claim database study.

BACKGROUND: Osteoporotic vertebral compression fractures (OVCF) is a common and often debilitating complication of osteoporosis, leading to significant morbidity and increased mortality. Percutaneous vertebroplasty (PVP) and Percutaneous kyphoplasty (PKP) are recommendable surgical treatments for OVCF. OBJECTIVE: To evaluate PVP/PKP utilisation and their related direct medical costs for OVCF treatment in China from the payer perspective. METHODS: A population-based medical claims database of a metropolitan city in China was analysed from the payer perspective, which included all inpatient claims from 01/01/2015 to 31/12/2017. All vertebral fractures patients that met the eligibility criteria (aged ≥50 years old, having vertebral fracture diagnosis, without unrelated diseases diagnoses such as tumour and scoliosis, received PVP/PKP) were deemed as OVCF patients. Baseline characteristics, surgery rate, length of stay in hospital, time to re-surgery, and costs (including costs per hospitalisation and annual costs) were described. Survival analysis function was used to estimate the re-surgery rate. RESULTS: Of the 50,686 patients with OVCF identified, 14,527 (28.66%) received a total number of 15,599 records of PVP/PKP surgeries from 2015 to 2017. Mean age was 75 at the first surgery captured in the database analysis period; females accounted for 79.54% of all cases. The median length of surgery stay was 9 days. Cumulative re-surgery rates were 1.22% in 30 days, 2.58% in 90 days, 3.61% in 183 days, 5.42% in 1 year, and 7.95% in 2 years. There was no significant difference in re-surgery rate between PVP and PKP (p = 0.3897). The median time to the re-surgery was 139 days. Mean costs per PVP/PKP-related hospitalisation were 35,906 CNY/5122 USD (34,195 CNY/4878USD for PVP, 44,414 CNY/6336 USD for PKP, p < 0.01). The overall costs of hospitalisation averaged 186.61 million CNY (26.62 million USD) per year in this metropolitan city. CONCLUSION: From 2015 to 2017, nearly one-third of OVCF inpatients received PVP/PKP and the re-surgery rate was 7.95%. PVP/PKP procedures for OVCF place a high economic burden for both the healthcare system and patients. Early detection and treatment of patients with osteoporosis are critical in China.

Vertebral Augmentation Involving Vertebroplasty or Kyphoplasty for Cancer-Related Vertebral Compression Fractures: An Economic Analysis.

BACKGROUND: Untreated vertebral compression fractures can have serious clinical consequences and impose a considerable impact on patients' quality of life and on caregivers. Since non-surgical management of these fractures has limited effectiveness, vertebral augmentation procedures are gaining acceptance in clinical practice for pain control and fracture stabilization. The objective of this analysis was to determine the cost-effectiveness and budgetary impact of kyphoplasty or vertebroplasty compared with non-surgical management for the treatment of vertebral compression fractures in patients with cancer. METHODS: We performed a systematic review of health economic studies to identify relevant studies that compare the cost-effectiveness of kyphoplasty or vertebroplasty with non-surgical management for the treatment of vertebral compression fractures in adults with cancer. We also performed a primary cost-effectiveness analysis to assess the clinical benefits and costs of kyphoplasty or vertebroplasty compared with non-surgical management in the same population. We developed a Markov model to forecast benefits and harms of treatments, and corresponding quality-adjusted life years and costs. Clinical data and utility data were derived from published sources, while costing data were derived using Ontario administrative sources. We performed sensitivity analyses to examine the robustness of the results. In addition, a 1-year budget impact analysis was performed using data from Ontario administrative sources. Two scenarios were explored: (a) an increase in the total number of vertebral augmentation procedures performed among patients with cancer in Ontario, maintaining the current proportion of kyphoplasty versus vertebroplasty; and (b) no increase in the total number of vertebral augmentation procedures performed among patients with cancer in Ontario but an increase in the proportion of kyphoplasties versus vertebroplasties. RESULTS: The base case considered each of kyphoplasty and vertebroplasty versus non-surgical management. Kyphoplasty and vertebroplasty were associated with an incremental cost-effectiveness ratio of $33,471 and $17,870, respectively, per quality-adjusted life-year gained. The budgetary impact of funding vertebral augmentation procedures for the treatment of vertebral compression fractures in adults with cancer in Ontario was estimated at about $2.5 million in fiscal year 2014/15. More widespread use of vertebral augmentation procedures raised total expenditures under a number of scenarios, with costs increasing by $67,302 to $913,386. CONCLUSIONS: Our findings suggest that the use of kyphoplasty or vertebroplasty in the management of vertebral compression fractures in patients with cancer may be a cost-effective strategy at commonly accepted willingness-to-pay thresholds. Nonetheless, more widespread use of kyphoplasty (and vertebroplasty to a lesser extent) would likely be associated with net increases in health care costs.

Percutaneous Vertebroplasty for Pathological Vertebral Compression Fractures Secondary to Multiple Myeloma--Medium-Term and Long-Term Assessment of Pain Relief and Quality of Life.

BACKGROUND: In patients with multiple myeloma (MM) there is a high risk of compression fractures of the spine. In the majority of cases, the method of treatment is percutaneous vertebroplasty (PV) or kyphoplasty (PK). The number of studies verifying their efficacy in MM is still relatively small. OBJECTIVES: The aim of this study has been to assess medium- and long-term pain relief as well as improvement in the quality of life (QL) after PV in MM cases. MATERIAL AND METHODS: There was a prospective group of 34 MM cases in which a total of 131 vertebral bodies were augmented by means of PV. It was possible to follow up 22 patients who agreed to take part in the assessment. Their level of daily activity and the level of pain were assessed using the Oswestry Back Pain scale and a visual analogue scale (VAS) before PV and at a later date (medium-term follow up was a mean of 10 months after the last operation). Five out of eight cases in which 4.5-5 years had elapsed since the first PV were tested again (long-term follow-up). RESULTS: Relief of pain and improvement of QL, assessed a mean of 10 months after PV, proved to be statistically significant. On the average, pain decreased by 4.7 points as measured on the VAS scale and the average improvement in the QL measured on the Oswestry scale was 27.7%. There were no neurological or general complications. After 4.5-5 years, there has not been any significant change in the level of pain relief or the improvement in the QL in the 5 cases in which long-term assessment was possible. CONCLUSIONS: In MM cases, PV is a simple, effective and safe method for the treatment of vertebral infiltration and compression fractures, giving permanent long-term pain relief and concomitant improvement in the QL.

Outcomes of arthroscopic Hill-Sachs remplissage and anterior Bankart repair: a retrospective controlled study including ultrasound evaluation of posterior capsulotenodesis and infraspinatus strength assessment.

BACKGROUND: Hill-Sachs lesions are compression fractures that result from shoulder dislocation. They involve "engaging" the humeral head on the anterior glenoid rim when the arm is abducted and externally rotated. The defect grows as the number of dislocations increases. HYPOTHESIS: Arthroscopic remplissage and anterior Bankart repair do not significantly affect infraspinatus strength while ensuring healing of the capsulotenodesis. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Sixty-one patients with traumatic anterior shoulder instability treated by arthroscopic Bankart repair and Hill-Sachs remplissage at least 24 months previously were compared with a control group of 40 healthy participants. Preoperative imaging included magnetic resonance imaging for Bankart lesion identification and computed tomography to quantify the humeral head defect. Active range of motion and clinical scores (Walch-Duplay, Constant-Murley, and Rowe) were assessed. External rotation (ER) and internal rotation (IR) were measured with arm at the side (ER1 and IR1) and abducted at 90° (ER2 and IR2). Infraspinatus strength was assessed with the scapula free (infraspinatus strength test [IST]) and retracted (infraspinatus scapula retraction test [ISRT]). Infraspinatus tenodesis and posterior capsulodesis healing were evaluated by ultrasound (US). RESULTS: The follow-up median was 39.5 months (range, 24-56 months). One patient experienced a recurrence of instability at 34 months. In the remplissage patients, ER1 was significantly lower in the affected compared with the unaffected shoulder (P < .001). Mean IST and ISRT strength values did not show differences between sides. The mean Constant-Murley score rose from 62.9 ± 7.1 to 90 ± 5.2 (P < .0001). The Walch-Duplay and Rowe scores were excellent in 23 (78.6%), good in 6 (17.8%), and poor in 1 patient (both scores). The remplissage group had significantly lower ER1 (P < .001), ER2 (P < .001), and IR2 (P < .01) values compared with the control group. Differences in IST and ISRT between the groups were not significant. Capsulotenodesis healing and filling of the Hill-Sachs defect were confirmed by dynamic US in all subjects. CONCLUSION: Arthroscopic remplissage is a reliable approach to Hill-Sachs lesions. The ER and IR restriction does not significantly affect quality of life. Infraspinatus strength recovery is satisfactory even compared with healthy subjects. Ultrasound examination allows accurate evaluation of capsulotenodesis healing.

A review of vertebroplasty for osteoporotic and malignant vertebral compression fractures.

Vertebral compression fractures are a common clinical problem and the incidence of them will increase with the ageing population. Traditionally management has been conservative; however, there has been a growing trend towards vertebroplasty as an alternative therapy in patients with persisting severe pain. NICE produced guidance in 2003 recommending the procedure after 4 weeks of conservative management. Recent high-quality studies have been contradictory and there is currently a debate surrounding the role of the procedure with no agreement in the literature. We examine the evidence in both osteoporotic and malignant vertebral compression fractures; we also describe the benefits and side effects, alternative treatment options and the cost of the procedure. Finally, we recommend when vertebroplasty is most appropriately used based on the best available evidence.

Vertebroplasty versus conservative treatment in acute osteoporotic vertebral compression fractures (Vertos II): an open-label randomised trial.

BACKGROUND: Percutaneous vertebroplasty is increasingly used for treatment of pain in patients with osteoporotic vertebral compression fractures, but the efficacy, cost-effectiveness, and safety of the procedure remain uncertain. We aimed to clarify whether vertebroplasty has additional value compared with optimum pain treatment in patients with acute vertebral fractures. METHODS: Patients were recruited to this open-label prospective randomised trial from the radiology departments of six hospitals in the Netherlands and Belgium. Patients were aged 50 years or older, had vertebral compression fractures on spine radiograph (minimum 15% height loss; level of fracture at Th5 or lower; bone oedema on MRI), with back pain for 6 weeks or less, and a visual analogue scale (VAS) score of 5 or more. Patients were randomly allocated to percutaneous vertebroplasty or conservative treatment by computer-generated randomisation codes with a block size of six. Masking was not possible for participants, physicians, and outcome assessors. The primary outcome was pain relief at 1 month and 1 year as measured by VAS score. Analysis was by intention to treat. This study is registered at ClinicalTrials.gov, number NCT00232466. FINDINGS: Between Oct 1, 2005, and June 30, 2008, we identified 431 patients who were eligible for randomisation. 229 (53%) patients had spontaneous pain relief during assessment, and 202 patients with persistent pain were randomly allocated to treatment (101 vertebroplasty, 101 conservative treatment). Vertebroplasty resulted in greater pain relief than did conservative treatment; difference in mean VAS score between baseline and 1 month was -5·2 (95% CI -5·88 to -4·72) after vertebroplasty and -2·7 (-3·22 to -1·98) after conservative treatment, and between baseline and 1 year was -5·7 (-6·22 to -4·98) after vertebroplasty and -3·7 (-4·35 to -3·05) after conservative treatment. The difference between groups in reduction of mean VAS score from baseline was 2·6 (95% CI 1·74-3·37, p<0·0001) at 1 month and 2·0 (1·13-2·80, p<0·0001) at 1 year. No serious complications or adverse events were reported. INTERPRETATION: In a subgroup of patients with acute osteoporotic vertebral compression fractures and persistent pain, percutaneous vertebroplasty is effective and safe. Pain relief after vertebroplasty is immediate, is sustained for at least a year, and is significantly greater than that achieved with conservative treatment, at an acceptable cost. FUNDING: ZonMw; COOK Medical.

Biochemical bone markers in the assessment and pamidronate treatment of children and adolescents with osteogenesis imperfecta.

AIM: To assess the role of biochemical bone markers in classification of children with osteogenesis imperfecta (OI), their possible association with vertebral compression fractures in milder forms of OI and their role in monitoring of intravenous pamidronate (APD) treatment. METHODS: Serum total alkaline phosphatase (ALP), bone ALP isoforms (in a subgroup), osteocalcin, type I procollagen carboxy-terminal propeptide, carboxy-terminal telopeptide of type I collagen, and urine deoxypyridinoline (DPD) were measured in a cross-sectional study of 130 untreated individuals, 0.25-20.9years (median 6.7), with OI types I, III and IV. Of those, sixty-nine were also assessed longitudinally during monthly APD treatment. Bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry. RESULTS: Significant differences in bone markers, however not sufficient for individual clinical use, were found in the larger untreated group but not between subgroups with or without vertebral compressions. All bone markers decreased during treatment for 1.0-12.5years, but with different relative amounts. Changes were not correlated to the improvement in BMD, mobility or pain. CONCLUSION: Bone markers are, despite significant differences, not useful for the classification of OI type in the individual child and are not associated with vertebral compressions. Serum ALP and urinary DPD are sensitive in monitoring bisphosphonate treatment.

Comparison of 5766 vertebral compression fractures treated with or without kyphoplasty.

BACKGROUND: The majority of the 700,000 osteoporotic vertebral compression fractures (VCFs) that occur annually in the United States affect women. The total treatment costs exceed $17 billion and approximate the total costs of breast cancer ($13 billion) and heart disease ($19 billion). Balloon-assisted percutaneous vertebral augmentation with bone cement (kyphoplasty) reportedly reduces VCF-related pain and accelerates return of independent functional mobility. Kyphoplasty may decrease overall cost of VCF treatment costs by reducing use of posttreatment medical resources. QUESTIONS/PURPOSES: We evaluated complications, mortality, posthospital disposition, and treatment costs of kyphoplasty compared with nonoperative treatment using the Nationwide Inpatient Sample database. METHODS: We identified 5766 VCFs (71% female) in patients 65 years of age or older with nonneoplastic VCF as the primary diagnosis in nonroutine hospital admissions; 15.3% underwent kyphoplasty. Demographic data, medical comorbidities, and fracture treatment type were recorded. Outcomes, including complications, mortality, posthospital disposition, and treatment costs, were compared for each treatment type. RESULTS: Women were more likely to be treated with kyphoplasty than were men. Patients undergoing kyphoplasty had comorbidity indices equivalent to those treated nonoperatively. Kyphoplasty was associated with a greater likelihood of routine discharge to home (38.4% versus 21.0% for nonoperative treatment), a lower rate of discharge to skilled nursing (26.1% versus 34.8%) or other facilities (35.7% versus 47.1%), a complication rate equivalent to nonoperative treatment (1.7% versus 1.0%), and a lower rate of in-hospital mortality (0.3% versus 1.6%). Kyphoplasty was associated with higher cost of hospitalization (mean $37,231 versus $20,112). CONCLUSIONS: Kyphoplasty for treatment of VCF in well-selected patients may accelerate the return of independent patient function as indicated by improved measures of hospital discharge. The initially higher cost of treatment may be offset by the reduced use of posthospital medical resources. LEVEL OF EVIDENCE: Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Polymethylmethacrylate and radioisotopes in vertebral augmentation: an explanation of underlying principles.

We recently reported a novel concept for combining radioactive isotope technology with polymethylmethacrylate (PMMA) cement used for vertebral augmentation and have advocated that pain physicians become aware of this new concept when treating malignant compression fractures. The use of vertebral augmentation for malignant compression fractures is steadily increasing, and the goal of this novel approach would be to stabilize the fractured vertebral body while also controlling proliferation of the tumor cells in the vertebral body that caused the vertebral fracture. This approach would therefore provide mechanical stabilization of the fractured vertebral body at the same time as direct targeting of the cancer cells causing the fracture. For our analysis, we investigated six specific radioisotopes with regard to physical and biologic properties as they would interact with PMMA and local bone metastatic disease, taking into consideration anatomical, biological and physical characteristics. The radioisotopes investigated include beta emitting (plus and minus) sources, as well as low energy and mid-energy photon sources and are: P-32, Ho-166, Y-90, I-125, F-18, and Tc-99m. We review the advantages and disadvantages of each radioisotope. In addition, this paper serves to provide pain physicians with a basic background of the biologic principles (Biologically Effective Dose) and statistical modeling (Monte Carlo method) used in that analysis. We also review the potential complications when using radioactive sources in a clinical setting. Understanding the methodologies employed in determining isotope selection empowers the practitioner by fostering understanding of this presently theoretical treatment option. We believe that embedding radioisotopes in PMMA is merely a first step in the road of local treatment for symptomatic local lesions in the setting of systemic disease.

Prospective assessment of pain and functional status after vertebroplasty for treatment of vertebral compression fractures.

BACKGROUND AND PURPOSE: There has been no prospective evaluation of vertebroplasty using a validated instrument. We describe the pain and functional status of 72 patients before and after vertebroplasty, as prospectively evaluated by the Vertebral Compression Fracture Pain and Functional Disability Questionnaire. METHODS: Of 161 consecutive patients, 72 consented to participate in the study and self-completed the questionnaire prior to undergoing vertebroplasty. Differences in pain and distress before and after vertebroplasty, and between the first and second follow-up intervals, were evaluated. Mean scores for each of 24 activities of daily living (ADLs) were plotted at the baseline and first and second follow-up intervals. RESULTS: The mean (SD) patient age was 74 (10) years; 80% were female. On the 0 (no pain) to 10 (pain as bad as it could be) visual analog pain scale, patients reported significantly more pain, on average, before undergoing percutaneous vertebroplasty (PV) than at the first follow-up interval (mean 5.8 vs 3.5, p<0.001). The reduction in reported pain following vertebroplasty persisted at the second follow-up on both the visual analog and adjectival pain scales. Among the 24 ADLs, between 25% and 69% of patients reported a mean improvement of at least 1 level on the 5-point ADL scale, and between 14% and 55% reported a mean improvement of at least two levels. The majority of the improvement in reported functional status following vertebroplasty was sustained at the second follow-up interval. CONCLUSION: PV resulted in substantial, lasting reduction in pain and improvement in ability to perform ADLs.

Radioisotopes and vertebral augmentation: dosimetric analysis of a novel approach for the treatment of malignant compression fractures.

PURPOSE: Vertebral compression fractures (VCFs), a major cause of morbidity and debilitating pain, often results from secondary tumor metastases to the skeleton. Vertebral augmentation is a palliative technique developed to treat VCFs and involves the injection of polymethyl methacrylate (PMMA) to augment the fractured vertebral body. The authors investigate the feasibility of radionuclide therapy coupled with vertebral augmentation to treat both the tumor metastases and VCFs. Six therapeutic radioisotopes, uniformly mixed in a PMMA bolus, were investigated for their dosimetric properties. METHODS AND MATERIALS: The MCNP5 Monte Carlo computer code was used to characterize the therapeutic dosimetric distribution within a cortical bone phantom for a 1 mm radial bolus of isotope-infused PMMA. Based on these data, the minimum activity required for a therapeutic treatment was calculated. RESULTS: The dosimetry from beta emitting Y-90, P-32, and Ho-166 decreased to 10% of its maximum therapeutic dose (R10%) after traveling 1.20 mm, 1.03 mm, and 0.97 mm, respectively, through cortical bone. Low photon energy I-125 had a slightly larger calculated R10% of 1.32 mm. Although F-18 and Tc-99m exhibited a more uniform distribution (R10%=1.72 mm and 1.94 mm, respectively), the lower dosimetric gradients resulted in significantly greater therapeutic implant activities relative to the other isotopes studied in this report. CONCLUSIONS: Radionuclide therapy coupled with vertebral augmentation is shown to be a feasible technique for the treatment of secondary skeletal metastases and its resulting side effects. Future studies will include a full clinical investigation to determine optimal treatment isotope(s).

Metastatic burst fracture risk assessment based on complex loading of the thoracic spine.

The mechanical integrity of vertebral bone is compromised when metastatic cancer cells migrate to the spine, rendering it susceptible to burst fracture under physiologic loading. Risk of burst fracture has been shown to be dependent on the magnitude of the applied load, however limited work has been conducted to determine the effect of load type on the stability of the metastatic spine. The objective of this study was to use biphasic finite element modeling to evaluate the effect of multiple loading conditions on a metastatically-involved thoracic spinal motion segment. Fifteen loading scenarios were analyzed, including axial compression, flexion, extension, lateral bending, torsion, and combined loads. Additional analyses were conducted to assess the impact of the ribcage on the stability of the thoracic spine. Results demonstrate that axial loading is the predominant load type leading to increased risk of burst fracture initiation, while rotational loading led to only moderate increases in risk. Inclusion of the ribcage was found to reduce the potential for burst fracture by 27%. These findings are important in developing a more comprehensive understanding of burst fracture mechanics and in directing future modeling efforts. The results in this study may also be useful in advising less harmful activities for patients affected by lytic spinal metastases.

Biomechanical comparison of unipedicular versus bipedicular kyphoplasty.

STUDY DESIGN: A cadaveric study comparing the biomechanics of unipedicular versus bipedicular kyphoplasty in the treatment of osteoporotic vertebral compression fractures. OBJECTIVES: The objectives of this study were to compare unipedicular kyphoplasty to bipedicular kyphoplasty in restoring strength, stiffness, and height to osteoporotic vertebral compression fractures and to study the degree of unilateral wedging when using a unipedicular versus bipedicular approach to kyphoplasty. SUMMARY OF BACKGROUND DATA: Osteoporotic vertebral compression fractures are a common ailment of the elderly that can lead to chronic pain and deformity. Recently developed treatments known as vertebroplasty and kyphoplasty provide pain relief by percutaneously augmenting the fractured vertebral body with polymethyl methacrylate via a transpedicular approach. Vertebroplasty via a unipedicular approach has been shown to provide comparable restoration of vertebral body stiffness when compared to a bipedicular approach. The anticipated benefits of a unipedicular approach include reduction in patient risk, operative time, radiation exposure, and cost. No studies have evaluated the efficacy of unipedicular kyphoplasty. MATERIAL AND METHODS: Two fresh-frozen human cadaveric spines (T3-L5) were disarticulated, and the vertebral bodies (n = 30) were compressed using an Instron 8521 machine, recording load versus displacement. The fractured vertebral bodies then underwent kyphoplasty via either a unipedicular or bipedicular approach. The augmented vertebral bodies were then recompressed. The strength, stiffness, and height restoration of the groups were compared. Following recompression, the risk for lateral wedging was evaluated by comparing lateral height measurements. RESULTS: Following fracture and subsequent kyphoplasty augmentation, the mean strength of the bipedicular group was 1.40 kN (+/- 0.38) versus 1.57 kN (+/- 0.55) in the unipedicular group. Average stiffness in the bipedicular group was 0.4387 kN/mm (+/- 0.2095) compared to 0.6880 kN/mm (+/- 0.3179) in the unipedicular group. Postcompression vertebral body height was restored to 96% of prefracture height in the bipedicular group and 94% of prefracture height in the unipedicular group. The mean absolute value of the difference in height between right and left side of the vertebral bodies was 1.06 mm (+/- 1.01) in the bipedicular group, whereas the unipedicular group had a mean of 1.78 mm (+/- 1.84). Statistical analysis using 1-way analysis of variance revealed no significant difference in any of the outcome measurements between the unipedicular and bipedicular groups (P < 0.05). CONCLUSIONS: Unipedicular kyphoplasty is comparable to bipedicular kyphoplasty in the restoration of vertebral body strength, stiffness, and height in experimentally induced vertebral compression fractures. There was no greater risk for lateral wedging in the unipedicular group compared to the bipedicular group. Given the advantages of a unipedicular approach with respect to vertebral pedicle cannulation risk, operative time, radiation exposure, and cost, this study would support the use of a unipedicular approach to kyphoplasty in the treatment of vertebral compression fractures.

[Quality of life assessment in osteoporotic patients with and without vertebral fractures].

INTRODUCTION: Vertebral fractures are assotiated with back pain and disability, but relatively little is known about their impact on quality of life of these patients. The aim of the study was to compare the quality of life of osteoporotic patients with and without vertebral fractures. MATERIAL AND METHODS: Bone mineral density measurement was done by dual-energy X-ray absorptiometry using LUNAR DPX-L in patients with osteoporosis divided into 2 groups: Group I (33 patients) with and Group II (30 patients) without vertebral fractures. Quality of life assessment was done using the Qualeffo-41. Statistical analysis was done using student t-test and Mann-Whitney U test. RESULTS: The results of Qualeffo-41 questionnaire suggest highly significant differences in quality of life between patients with and patients without vertebral fractures (p<0.001). Impaired quality of life in patients with vertebral fractures was evident in all domains of the questionnaire: pain (p=0.017), activities of daily living (p<0.001), jobs around the house (p=0.007), mobility (p<0.001), leisure, social activities (p=0.002), general health perception (p=0.002) and mental function (p=0.025). DISCUSSION: Health-related quality of life may be assessed using generic or disease-specific instruments. The Qualeffo-41 questionnaire is a disease-specific instrument which was developed by a working group of the European Foundation for Osteoporosis and has a great face and content validity in assessing quality of life in osteoporotic patients. CONCLUSION: Osteoporotic patients with vertebral fractures have a significantly impaired quality of life compared with osteoporotic patients without vertebral fractures.