Kyphoplasty For Osteoporotic Vertebral Fractures Research Articles

Risk Factors for Bone Cement Displacement After Percutaneous Kyphoplasty in Osteoporotic Vertebral Fractures: A Retrospective Analysis.

BACKGROUND Bone cement displacement (BCD), which has received increasing attention from scholars, is a serious complication following vertebroplasty in patients with osteoporotic vertebral fractures (OVFs), and percutaneous kyphoplasty (PKP) might promote its occurrence. However, few studies have systematically explored the risk factors of BCD after PKP. This research aimed to study the risk factors for BCD following PKP. MATERIAL AND METHODS The clinical data of patients with OVFs treated with PKP from June 2016 to August 2022 in our department were retrospectively reviewed. Patients were categorized into the bone cement displacement group and the bone cement non-displacement group. Data on the subjects and their radiologic images were gathered for univariate analysis and binary logistic regression analysis. The receiver operating characteristic (ROC) curve and confusion matrix were utilized to assess the discrimination ability. RESULTS We included 181 patients, of which 12 had BCD after PKP. Binary logistic regression analysis revealed that independent risk factors associated with BCD after PKP were: high BMI, high restoration rate of the Cobb angle, high distance between the bone cement and the vertebral endplates, and presence of bone cement leakage. The ROC curve and confusion matrix indicates that logistic regression exhibited a strong predictive value for BCD. CONCLUSIONS Patients with a high BMI, a high restoration rate of the Cobb angle, a high distance between the bone cement and the vertebral endplates, and bone cement leakage have an increased risk of BCD after PKP.

Risk Factors for Residual Back Pain After Balloon Kyphoplasty for Osteoporotic Vertebral Fracture.

Balloon kyphoplasty (BKP) is a method for the management of osteoporotic vertebral body fracture (OVF). However, improvement in back pain (BP) is poor in some patients, also previous reports have not elucidated the exact incidence and risk factors for residual BP after BKP. We clarified the characteristics of residual BP after BKP in patients with OVF. In this study, we hypothesize that some risk factors may exist for residual BP 2years after the treatment of OVF with BKP. A multicenter cohort study was performed where patients who received BKP within 2months of OVF injury were followed-up for 2years. BP at 6months after surgery and final observation was evaluated by Visual Analog Scale (VAS) score. Patients with a score of 40mm or more were allocated to the residual BP group, and comparisons between the residual back pain group and the improved group were made for bone density, kyphosis, mobility of the fractured vertebral body, total spinal column alignment, and fracture type (fracture of the posterior element, pedicle fracture, presence or absence of posterior wall damage, etc.). Also, Short Form 36 (SF-36) for physical component summary (PCS) and mental component summary (MCS) at the final follow-up was evaluated in each radiological finding. Of 116 cases, 79 (68%) were followed-up for 2years. Two years after the BKP, 26 patients (33%) experienced residual BP. Neither age nor sex differed between the groups. In addition, there was no difference in bone mineral density, BKP intervention period (period from onset to BKP), and osteoporosis drug use. However, the preoperative height ratio of the vertebral body was significantly worse in the residual BP group (39.8% vs. 52.1%; p = 0.007). Two years after the operation, the vertebral body wedge angle was significantly greater in the residual BP group (15.7° vs. 11.9°; p = 0.042). In the multiple logistic regression model with a preoperative vertebral body height ratio of 50% or less [calculated by receiver operating characteristic (ROC) curve], the adjusted odds ratio for residual BP was 6.58 (95% confidence interval 1.64-26.30; p = 0.007); similarly, patients with vertebral body height ratio less than 50% had a lower score of SF-36 PCS 24.6 vs. 32.2 p = 0.08. The incidence of residual BP 2years after BKP was 33% in the current study. The risk factor for residual BP after BKP was a preoperative vertebral body height ratio of 50% or less, which should be attentively assessed for the selection of a proper treatment scheme and to provide adequate stabilization. III.

Vertebral augmentation by kyphoplasty in osteoporotic vertebral fractures: A clinical experience

Vertebral augmentation by kyphoplasty in osteoporotic vertebral fractures: A clinical experience

Preoperative planning of compact zone trajectory is necessary in treating osteoporotic vertebral compression fracture with endplate involvement: A prospective randomized controlled study.

This prospective randomized controlled study compares the clinical and radiological outcomes between reduction methods with or without compact trabecular bone during percutaneous kyphoplasty in osteoporotic vertebral fractures. The cohort of 100 patients who underwent percutaneous kyphoplasty was randomly divided into groups A (guide pin and balloon introduced directly into fracture site) and B (guide pin and balloon inserted away fracture site). The surgery duration, clinical and radiological outcomes postoperatively and at follow-up, and complications of cement leakage and adjacent fracture were recorded. Patients were followed up for an average of 20.18 months. The clinical outcomes were assessed using the Oswestry disability index and visual analogue scale. The 2 groups had similar patient demographics, surgery times, and volume of cement injected. The method using elevation of the collapsed endplate indirectly had no significant influence on radiological outcomes but significantly decreased the occurrence of intradiscal cement leakage and improved 1- and 12-month postoperative functional outcomes. Elevating and reinforcing the collapsed endplate rather than just filling the defect during percutaneous kyphoplasty is safe and effective. This technique decreased pain and improved function with lower rates of further collapse of the osteoporotic vertebrae compared to defect-filling alone.

The relationship between pain relief and the amount and distribution of injected cement in kyphoplasty for osteoporotic vertebral fractures.

This study aimed to compare the relationship of pain relief with the amount and distribution of injected cement in kyphoplasty for osteoporotic vertebral fractures. This cohort study was conducted on 90 patients with osteoporotic vertebral fractures who needed chronic pain medication. Patients underwent kyphoplasty balloon surgery, and polymethylmethacrylate (PMMA) or bone cement was injected into the created cavities and the volume of injected cement was recorded. After the surgery, the distribution of cement was measured using a computed tomography (CT) scan in the coronal, sagittal, and axial axes of the vertebra, and the percentage of cement distribution was evaluated using Photoshop software in these three axes, followed by the pattern of cement distribution. The cement was measured in the entire vertebra. The patients were evaluated over a period of 6 months, and the amount of pain improvement was measured by the VAS scale in 24 hours, two weeks, six weeks, and six months after surgery. In this study, the data of 90 patients with a mean age of 72.5±10.9 years were included in the study. The mean volume of cement injected was 1.2±5.8 cc, followed by the mean percentage of cement distribution (47.7±7.4%); the mean pain score before the operation (8.7±1.3), the mean pain score 24 hours after the operation (7.7±1.4), the mean pain score 2 weeks after the operation (4.8±1.3), the mean pain score 6 weeks after the operation (3.6±1.2) and the mean pain score 6 months after the operation (3.5±1.4) were evaluated after collection. The pain intensity 24 hours after the operation had a significant positive correlation with the percentage of cement distribution and pain intensity before the operation. The intensity of pain 2 weeks after the operation was positively correlated with the age of the patients and the intensity of pain before the operation. The pain intensity 6 weeks after the operation was significantly correlated with the age of the patients and the pain intensity before the operation. The intensity of pain 6 months after the operation was positively linked to the age of the patients and negatively correlated with the percentage of cement distribution. The pain reduction has changed significantly in the 4 measured intervals, and during a period of 6 months, there was a significant improvement in the pain level of the patients continuously. It was found that the rate of recovery of the patient's pain has increased by increased distribution of injected cement. Although this reduction in pain during the 6-month period was not significantly related to the variables of gender, smoking, history of corticosteroid use, and the volume of injected cement. The balloon kyphoplasty is a safe and successful method for treating symptomatic vertebral fractures. Kyphoplasty is associated with significant pain relief, improved quality of life, and kyphosis correction. The volume of cement injected had no effect on reducing patients' pain after the operation, but a higher percentage of cement distribution was associated with a better response in patients.

Lower ratio of adjacent to injured vertebral bone quality scores can predict augmented vertebrae recompression following percutaneous kyphoplasty for osteoporotic vertebral fractures with intravertebral clefts.

Despite the favorable clinical outcome of percutaneous kyphoplasty (PKP) in symptomatic osteoporotic vertebral fractures (OVFs) patients with intravertebral clefts (IVCs), previous studies have demonstrated a high incidence of augmented vertebrae recompression (AVR). We aim to evaluate the usefulness of the adjacent and injured vertebral bone quality scores (VBQS) based on T1-weighted MRI images in AVR after PKP for OVFs with IVCs. Patients who underwent PKP for single OVFs with IVCs between January 2014 and September 2020 were reviewed and met the inclusion criteria. The follow-up period was at least 2 years. Relevant data affecting AVR were collected. Pearson and Spearman correlation coefficients were used to calculate the correlation between the injured and adjacent VBQS and BMD T-score. We determined independent risk factors and critical values using binary logistic regression analysis and receiver operating characteristic curves (ROC). A total of 165 patients were included. Recompression group was found in 42 (25.5%) patients. The independent risk factors for AVR were lumbar BMD T-score (OR = 2.53, p = 0.003), the adjacent VBQS (OR = 0.79, p = 0.016), the injured VBQS (OR = 1.27, p = 0.048), the ratio of adjacent to injured VBQS (OR = 0.32, p < 0.001), and cement distribution pattern. Among these independent significant risk factors, the prediction accuracy of the ratio of adjacent to injured VBQS was the highest (Cutoff = 1.41, AUC = 0.753). Additionally, adjacent and injured VBQS were negatively correlated with lumbar BMD T-scores. For the patients after PKP treatment for OVFs with IVCs, the ratio of adjacent to injured VBQS had the best prediction accuracy in predicting recompression and when the ratio of adjacent to injured VBQS was <1.41, the augmented vertebrae were more likely to have recompression in the future.

Thoracolumbar fascia injury in osteoporotic vertebral fracture: the important concomitant damage

BackgroundThoracolumbar fascia injury (FI) is rarely discussed in osteoporotic vertebral fracture (OVF) patients in previous literature and it is usually neglected and treated as an unmeaning phenomenon. We aimed to evaluate the characteristics of the thoracolumbar fascia injury and further discuss its clinical significance in the treatment of kyphoplasty for osteoporotic vertebral fracture (OVF) patients.MethodsBased on the presence or absence of FI, 223 OVF patients were divided into two groups. The demographics of patients with and without FI were compared. The visual analogue scale and Oswestry disability index scores were compared preoperatively and after PKP treatment between these groups.ResultsThoracolumbar fascia injuries were observed in 27.8% of patients. Most FI showed a multi-level distribution pattern which involved a mean of 3.3 levels. Location of fractures, severity of fractures and severity of trauma were significantly different between patients with and without FI. In further comparison, severity of trauma was significantly different between patients with severe and non-severe FI. In patients with FI, VAS and ODI scores of 3 days and 1 month after PKP treatment were significantly worse compared to those without FI. It showed the same trend in VAS and ODI scores in patients with severe FI when compared to those patients with non-severe FI.ConclusionsFI is not rare in OVF patients and presents multiple levels of involvement. The more serious trauma suffered, the more severe thoracolumbar fascia injury presented. The presence of FI which was related to residual acute back pain significantly affected the effectiveness of PKP in treating OVFs.Trial registrationretrospectively registered.

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

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). 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. 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%. 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.

EFFECTIVENESS AND SAFETY OF SPINEJACK SYSTEM IN THE MANAGEMENT OF VERTEBRAL FRAGILITY FRACTURES: A SYSTEMATIC REVIEW

Introduction: The SpineJackⓇ (SJ) system received FDA clearance in 2018, therefore this device is currently available to perform kyphoplasty in osteoporotic vertebral fractures. This study aims to assess the outcome of the SJ system in the management of vertebral fragility fractures (VFFs). Evidence Acquisition and Synthesis: OVID-MEDLINEⓇ, EMBASE, Cochrane Library, SCOPUS, Springer Link, Web of Science, Google Scholar and PubMed were searched from January 2015 to November 2021 to identify relevant studies. The methodological qualities of the studies were evaluated, and relevant data were extracted. Seven clinical trials, recruiting 644 patients with 690 VFFs were included. Although PVP, balloon kyphoplast (BKP) and SJ showed comparable effectiveness in back pain relief in patients with VFFs, SJ showed a faster and higher pain relief and a better quality of life, compared with the other two augmentation techniques. Moreover, patients treated with SJ, compared with PVP and BKP, showed a better vertebral body height (VBH) restoration and kyphotic correction; these findings were confirmed also at long-term follow-up. Asymptomatic cement leakage and adjacent level fractures (ALFs) were observed in patients treated with SJ, but with a lower incidence compared with PVP and BKP. Conclusions: This systematic review shows that SJ has an excellent risk/benefit profile and is more effective than the other augmentation techniques in VBH restoration and kyphotic correction. These findings correlate with a better postoperative quality of life.

Characteristics of failed cases after balloon kyphoplasty for osteoporotic vertebral fractures

Characteristics of failed cases after balloon kyphoplasty for osteoporotic vertebral fractures

Incidence of symptomatic adjacent vertebral fractures after percutaneous balloon kyphoplasty in osteoporotic vertebral fractures

Incidence of symptomatic adjacent vertebral fractures after percutaneous balloon kyphoplasty in osteoporotic vertebral fractures

Balloon kyphoplasty for osteoporotic vertebral fracture with hiatal hernia: A case report

Balloon kyphoplasty for osteoporotic vertebral fracture with hiatal hernia: A case report

Functional Outcome of Kyphoplasty in Osteoporotic Vertebral Fractures in Patients with Severe Disability Above 60 Years of Age: Mid to Long Term Follow up.

Vertebral osteoporotic fractures are a worldwide problem and can cause significant morbidity. retrospective analysis reviewing functional outcome of 70 patients who underwent balloon-kyphoplasty(BK). Inclusion criteria, a-patients above 60 years of age b-symptomatic patients who failed conservative treatment c-radiological diagnosis of vertebral compression fracture(VCF). Primary outcome was evaluation of functional outcome in mid- (1-3 years) and long term (&gt;3 years). Secondary outcomes a-analysis of the functional outcome of patients with severe disability or worse in mid- and long-term b-comparison of functional outcome between mid-term and long term follow-up c-correlate number of levels operated on with functional outcome. There were 70 patients with average age of 74 years. Lumbar and thoracic VCFs were included. Average follow-up was 2.7 years. Twenty-eight patients had long-term follow-up of ≥ 3 years and the remaining 42 had mid-term follow-up of &gt; 1 year and &lt; 3 years. All patients experienced clinical and statistically significant improvement in their Oswestry Disability Index score. This was the case in mid-term and long-term follow-up. This was also the case for patients presenting with severe disability. There was no correlation between the number of levels and functional outcome. 1. Osteoporotic vertebral compression fractures are fragility fractures and can be associated with significant morbidity. 2. Surgical treatment can help improve functional outcome on failure of conservative treatment. 3. Balloon kyphoplasty can significantly improve pa-tients' functional outcome in mid-term and long-term follow-up including patients presenting with severe disability or worse. 4. This study is of value in consenting kyphoplasty patients as they can expect an improvement in their disability in the mid-to-long term.

MRIでT2低輝度広範型の骨粗鬆症性椎体骨折に対するBalloon Kyphoplasty～保存療法との比較～

MRIでT2低輝度広範型の骨粗鬆症性椎体骨折に対するBalloon Kyphoplasty～保存療法との比較～

Risk Factors for Cement Leakage and Adjacent Vertebral Fractures in Kyphoplasty for Osteoporotic Vertebral Fractures.

Cement leakage and adjacent vertebral fractures are not uncommon after percutaneous augmentation. However, conclusive identification of risk factors for postprocedural complications remains elusive. The anticipation of leakage and successive fractures through the identification of risk factors will help physicians better inform patients of potential complications and establish procedural refinements key to risk reduction. The aim of this retrospective study was to summarize available reports of the risk factors for cement leak and adjacent vertebral fracture in or after kyphoplasty for osteoporotic vertebral compression fractures. A total of 102 cases of bilateral percutaneous kyphoplasty (PKP), performed between January 2014 and December 2016, were retrospectively reviewed. Each case surveyed in this review included a minimum 1-year follow-up and data on age, sex, bone mineral density, Visual Analog Scale score, preoperative compression rate, kyphotic angle, treatment time, the volume of cement, and the intactness of the vertebral posterior wall (computed tomography scan) were collected. Pearson χ test and independent samples test were used to determine the relative risk factors of cement leak and adjacent vertebral fracture in patient subsets. Diabetic status and alteration in the Cobb angle after PKP exhibited a statistically significant correlation with the incidence of new adjacent vertebral fracture (group B) (P<0.05). In addition, the integrity of vertebral walls (P=0.001) and the volume of injected cement (P=0.026) significantly boosted the potential risk of cement leakage (P<0.05), although these variables did not associate with the adjacent fracture. Additional examined variables, including age, sex, Visual Analog Scale scores, number of fractures were not significantly associated with leakage or adjacent vertebral fracture risk. Diabetes and the alteration of the Cobb angle following PKP are factors positively related to the occurrence of postoperative adjacent vertebral fractures. It is also demonstrated that the integrity of vertebral walls and average volumes of injected cement are the possible risk factors of cement leakage while performing the PKP.

Development of a scoring system for predicting adjacent vertebral fracture after balloon kyphoplasty

The incidence of adjacent vertebral fracture (AVFs) is reported to be 10%-38% after balloon kyphoplasty. However, no reports have established a system for prediction of AVF occurrence. To establish a scoring system for predicting AVF occurrence after balloon kyphoplasty for osteoporotic vertebral fractures (OVFs). A prospective cohort study. Consecutive elderly patients aged 65 years and older who underwent balloon kyphoplasty for OVFs within 2 months after the onset. AVF was confirmed by X-ray. From 2015 to 2017, 116 consecutive patients from 10 participating hospitals who underwent balloon kyphoplasty were enrolled in this study. Prior to study enrollment, each patient underwent plain X-ray, computed tomography (CT), and magnetic resonance imaging (MRI) of the thoracic and lumbar spine. Severity of pain was subjectively assessed using a visual analog scale (VAS) based on the average level of back pain that the patient had experienced in the preceding week. After enrollment, subjects underwent balloon kyphoplasty. Quality of life was evaluated using SF-36. Patients were followed up for at least 6 months. Of the 116 patients enrolled, 109 patients with all the required data at the time of enrolment and the 6-month follow-up were included in the study. A total of 32 patients (29%) showed AVFs within the 6-month follow-up. No significant differences were observed in each clinical outcome at 6-month follow-up, although higher VAS score for back pain at 1-month follow-up was observed in the AVF group (37.5) than in the non-AVF group (20.8, p<.001). Wedge angle of vertebrae before surgery was greater in the AVF group (21.6°) than in the non-AVF group (15.7°, p<.001). The change in wedge angle between pre- and postsurgery was greater in the AVF group than in the non-AVF group, whereas the change in local kyphosis was not significantly different. The multiple logistic regression model showed increased odds ratio (OR) of thoracic or thoracolumbar spine, old OVF presence, >25° kyphosis before surgery, and >10°correction for AVF. Based on this result, a simple scoring system for predicting AVF occurrence was developed. The total AVF score was calculated as the sum of the individual scores, which varied from 0 to 6. All patients with 5-6 points sustained AVF. More severe wedge angle before surgery, correction degree, old OVF presence, and thoracolumbar level were predictive factors for AVF. All patients with AVF risk score of 5 or more showed AVF. This information may aid preoperative risk assessment, informed shared decision-making, and consideration of potential alternative management strategies.

Delayed Height Loss After Kyphoplasty in Osteoporotic Vertebral Fracture with Severe Collapse: Comparison with Vertebroplasty

To compare clinical and radiographic outcomes and complications after vertebroplasty (VP) and kyphoplasty (KP) for osteoporotic vertebral fractures with severe collapse. Patients >65 years old with single osteoporotic vertebral fracture (T10-L2) with severe collapse (>40%) were prospectively enrolled and allocated to either KP or VP. Visual analog scale and Oswestry Disability Index were used for clinical assessment. Vertebral height loss (HL) and segmental kyphotic angle were measured radiographically at preoperative; postoperative; and 1-, 3-, 6-, and 12-month postoperative time points. Procedure-related and postoperative complications were recorded. Forty-six patients (27 with VP, 19 with KP) were enrolled. Visual analog scale and Oswestry Disability Index scores were similar at all time points in the 2 groups. Complication rates were also similar. HL and kyphotic angle were restored significantly in both groups. KP showed a better result in HL (KP group HL 20.5% ± 5.6% vs. VP group HL 29.8% ± 4.6%, P < 0.001). Progressive vertebral HL was observed, and patients with KP showed a greater collapse in height. At 1-year follow-up, there was no significant difference in vertebral height (KP group HL 29.8% ± 6.3% vs. VP group HL 33.0% ± 5.2%, P= 0.075). KP and VP showed similar improvements in pain and disability during treatment for osteoporotic vertebral fractures. Although vertebral height and segmental kyphotic angle were restored significantly in both groups, progressive vertebral HL was inevitable, especially after KP. This likely resulted from the difference of bone-cement interface as a consequence of balloon tamping in KP. Surgeons must consider the respective features of vertebral augmentations.

Clinical results of balloon kyphoplasty for osteoporotic vertebral fractures

Clinical results of balloon kyphoplasty for osteoporotic vertebral fractures

Vertebroplasty and Kyphoplasty for Osteoporotic Vertebral Fractures: What Are the Latest Data?

Osteoporotic vertebral compression fractures frequently result in significant morbidity and health care resource use. For patients with severe and disabling pain, vertebral augmentation (vertebroplasty and kyphoplasty) is often considered. Although vertebroplasty was introduced >30 years ago, there are conflicting opinions regarding the role of these procedures in the treatment of osteoporotic vertebral compression fractures. This review article updates clinicians on the published prospective randomized controlled data, including the most recent positive trials that followed initial negative trials in 2009. Analysis of multiple national claim datasets has also provided further insight into the utility of these procedures. Finally, we considered the recent recommendations of national organizations and medical societies that advise on the use of vertebral augmentation procedures for osteoporotic vertebral compression fractures.

The GDF5 mutant BB-1 enhances the bone formation induced by an injectable, poly(l-lactide-co-glycolide) acid (PLGA) fiber-reinforced, brushite-forming cement in a sheep defect model of lumbar osteopenia

Background ContextTargeted delivery of osteoinductive bone morphogenetic proteins (eg, GDF5) in bioresorbable calcium phosphate cement (CPC), potentially suitable for vertebroplasty and kyphoplasty of osteoporotic vertebral fractures, may be required to counteract augmented local bone catabolism and to support complete bone regeneration. The biologically optimized GDF5 mutant BB-1 may represent an attractive drug candidate for this purpose. PurposeThe aim of the current study was to test an injectable, poly(l-lactide-co-glycolide) acid (PLGA) fiber-reinforced, brushite-forming CPC containing low-dose BB-1 in a sheep lumbar osteopenia model. Study Design/ SettingThis is a prospective experimental animal study. MethodsBone defects (diameter 5 mm) were generated in aged, osteopenic female sheep and were filled with fiber-reinforced CPC alone (L4; CPC+fibers) or with CPC containing different dosages of BB-1 (L5; CPC+fibers+BB-1; 5, 100, and 500 µg BB-1; n=6 each). The results were compared with those of untouched controls (L1). Three and 9 months after the operation, structural and functional effects of the CPC (±BB-1) were analyzed ex vivo by measuring (1) bone mineral density (BMD); (2) bone structure, that is, bone volume/total volume (BV/TV) (assessed by micro-CT and histomorphometry), trabecular thickness (Tb.Th), and trabecular number (Tb.N); (3) bone formation, that is, osteoid volume/bone volume (OV/BV), osteoid surface/bone surface (OS/BS), osteoid thickness, mineralizing surface/bone surface (MS/BS), mineral apposition rate, and bone formation rate/bone surface; (4) bone resorption, that is, eroded surface/bone surface; and (5) compressive strength. ResultsCompared with untouched controls (L1), CPC+fibers (L4) and/or CPC+fibers+BB-1 (L5) significantly improved all parameters of bone formation, bone resorption, and bone structure. These effects were observed at 3 and 9 months, but were less pronounced for some parameters at 9 months. Compared with CPC without BB-1, additional significant effects of BB-1 were demonstrated for BMD, bone structure (BV/TV, Tb.Th, and Tb.N), and bone formation (OS/BS and MS/BS). The BB-1 effects on bone formation at 3 and 9 months were dose dependent, with 100 µg as the potentially optimal dosage. ConclusionsBB-1 significantly enhanced the bone formation induced by a PLGA fiber-reinforced CPC in sheep lumbar osteopenia. A single local dose as low as 100 µg BB-1 was sufficient to augment middle- to long-term bone formation. A CPC containing the novel GDF5 mutant BB-1 may thus represent an alternative to the bioinert, supraphysiologically stiff polymethylmethacrylate cement presently used to treat osteoporotic vertebral fractures by vertebroplasty and kyphoplasty.