Basivertebral foramen could be connected with intravertebral cleft: a potential risk factor of cement leakage in percutaneous kyphoplasty

Warning line for preventing bone cement leakage in surgery involving percutaneous kyphoplasty for osteoporotic vertebral compression fractures

Background

Percutaneous kyphoplasty (PKP) has achieved good clinical efficacy in the treatment of Osteoporotic vertebral compression fractures (OVCFs). However, how to reduce the bone cement leakage rate and improve safety during PKP surgery remains an urgent issue to be addressed in clinical practice. Therefore, the aim of this study was to identify a line, called the "warning line", to determine whether there is leakage of bone cement during PKP surgery.

Methods

From February 2018 to September 2022, 88 patients and 106 vertebral bodies with OVCFs treated with PKP by a single surgeon at our center were included in the study. Clinical general data were recorded. Vertebral bodies with bone cement reaching the apex of the posterior margin depression without leakage were designated Group A, whereas those with leakage were designated Group B. The posterior vertebral wall was divided into three equal parts in the postoperative three-dimensional CT scans, and the leakage rates at different positions of the posterior vertebral wall were analysed. In Group A without leakage, line b, called the warning line, was marked as the apex of cement diffusion.

Results

All 88 patients successfully underwent surgery, with a significant decrease in the postoperative VAS score. No neurological complications occurred. Bone cement leakage rate was 58.5%. There were 44 vertebral bodies in Group A and 62 in Group B. No significant differences were found between the two groups in terms of age, bone density, balloon pressure, contrast dose, or cement volume (P > 0.05). The bone cement leakage rates in the upper third, middle third, and lower third of the posterior vertebral wall were 25%, 61.1%, and 66.7%, respectively, with statistically significant differences (P < 0.05). In Group A without leakage, the warning line was approximately 6.8% of the sagittal diameter from the posterior vertebral margin.

Conclusions

PKP is a relatively safe treatment for OVCFs. Most bone cement leakage occurs in the middle and lower thirds of the posterior vertebral wall. When the apex of cement diffusion remains anterior to the warning line in PKP surgery, the posterior vertebral wall cement leakage rate is low.

Predictors for vertebral height deterioration in fractured vertebrae operated by percutaneous vertebroplasty

BACKGROUND

Vertebral height loss of fractured vertebrae treated by percutaneous vertebral augmentation (PVA) for osteoporotic vertebral compression fracture (OVCFs) during follow-up had been reported. Mostly, vertebral height loss and its relevant terms (e.g., "recompression", "recollapse" and "refracture") were defined according to immediate postoperative vertebral height as the baseline in published studies. By contrast, vertebral height deterioration (VHD) was defined according to preoperative vertebral height as the baseline in the present study. The aim of the study was to reveal predictors for VHD in fractured vertebrae operated by percutaneous vertebroplasty (PVP), with a specific focus on surgical factors.

METHODS

All patients with OVCFs treated by PVP between April 2016 and September 2018 were retrospectively reviewed. Patients were followed up for at least 12 months after procedure according to treatment protocol. VHD was defined as the presence of a decrease of vertebral height at final follow-up compared to preoperative. Clinical, radiological and surgical factors that might affect occurrence of VHD were assessed using univariate and multivariate analyses.

RESULTS

A total of 543 patients (females 80%, age 73.2 ± 8.1 years) with 681 fractured vertebrae who underwent PVP were enrolled. Mean follow-up time was 28.9 ± 13.4 months (range, 12-59 months). Incidence of VHD in fractured vertebrae was 48.9% (333/681). One clinical factor and four radiological factors, including fracture age (OR = 0.513, 95% CI 0.385-0.683, p = 0.000), fracture location (OR = 2.878, 95% CI 1.994-4.152, p = 0.000), fracture severity (OR = 0.521, 95% CI 0.386-0.703, p = 0.000), cortical defect on lateral wall (OR = 2.535, 95% CI 1.351-4.758, p = 0.004) and intravertebral cleft (OR = 2.362, 95% CI 1.488-3.750, p = 0.000), were independent predictors for VHD. However, all the surgical factors evaluated were not significant in final model analysis.

CONCLUSIONS

Surgical factors might play a negligible effect on VHD. VHD might be due to natural course of fracture/osteoporosis.

Interpretable Machine Learning Model to Predict Bone Cement Leakage in Percutaneous Vertebral Augmentation for Osteoporotic Vertebral Compression Fracture Based on SHapley Additive exPlanations

STUDY DESIGN

Retrospective study.

OBJECTIVES

Our objective is to create comprehensible machine learning (ML) models that can forecast bone cement leakage in percutaneous vertebral augmentation (PVA) for individuals with osteoporotic vertebral compression fracture (OVCF) while also identifying the associated risk factors.

METHODS

We incorporated data from patients (n = 425) which underwent PVA. To predict cement leakage, we devised six models based on a variety of parameters. Evaluate and juxtapose the predictive performances relied on measures of discrimination, calibration, and clinical utility. SHapley Additive exPlanations (SHAP) methodology was used to interpret model and evaluate the risk factors associated with cement leakage.

RESULTS

The occurrence rate of cement leakage was established at 50.4%. A binary logistic regression analysis identified cortical disruption (OR 6.880, 95% CI 4.209-11.246), the basivertebral foramen sign (OR 2.142, 95% CI 1.303-3.521), the fracture type (OR 1.683, 95% CI 1.083-2.617), and the volume of bone cement (OR 1.198, 95% CI 1.070-1.341) as independent predictors of cement leakage. The XGBoost model outperformed all others in predicting cement leakage in the testing set, with AUC of .8819, accuracy of .8025, recall score of .7872, F1 score of .8315, and a precision score of .881. Several important factors related to cement leakage were drawn based on the analysis of SHAP values and their clinical significance.

CONCLUSION

The ML based predictive model demonstrated significant accuracy in forecasting bone cement leakage for patients with OVCF undergoing PVA. When combined with SHAP, ML facilitated a personalized prediction and offered a visual interpretation of feature importance.

Risk factors for cement leakage after percutaneous vertebral augmentation for osteoporotic vertebral compression fractures: a meta-analysis

BACKGROUND

Osteoporotic vertebral compression fractures (OVCF) may necessitate percutaneous vertebral augmentation (PVA), a procedure not without its risks. One notable complication is cement leakage (CL), which can cause significant distress in patients. Despite its clinical importance, there remains a paucity of meta-analyses investigating these complications and their management in the existing literature.

MATERIAL AND METHODS

The authors systematically reviewed PubMed, Cochrane Library, Embase, and Web of Science databases up to February 2024 to identify studies examining CL following PVA treatment in OVCF. The authors assessed the quality of eligible cohort studies using the Newcastle-Ottawa Scale (NOS), extracted data on incidence, identified risk factors for CL, and conducting meta-analysis with Revman 5.2 software. The authors calculated odd ratios (OR) and mean differences (MD) with 95% CI applying random-effects models.

RESULTS

The authors identified twelve cohort studies that matched our strict inclusion criteria. These studies included a total of 2388 patients and 3392 vertebrae. CL was identified in 1132 vertebrae. Notable risk factors for CL included compromised cortical bone integrity (OR 5.00, 95% CI 3.01-8.29, P <0.00001), presence of intravertebral vacuum clefts (OR 1.68, 95% CI 1.07-2.65, P =0.03), basivertebral foramen sign (OR 1.77, 95% CI 1.09-2.89, P =0.02), and volume of cement used (MD 0.75, 95% CI 0.41-1.10, P <0.0001).

CONCLUSION

The authors' findings underscore the significance of cortical bone integrity, intravertebral vacuum cleft, basivertebral foramen sign, and cement volume as principal determinants of CL risk in PVA for OVCF. These insights advocate for tailored surgical strategies to mitigate the risk of CL in this patient population.

Anatomical and biomechanical characteristics of basivertebral foramen and its clinical significance

Basivertebral foramen is a natural orifice in the posterior wall of the vertebral body existing in humans and mammals, through which the basal vertebral vein, branch of lumbar artery and recurrent branch of spinal nerve enter and exit the vertebral body. Basivertebral foramen changes the local microstructure of the vertebral body, resulting in cortical defect and sparse trabecular bone in the central region of the vertebral body, thus affecting its biomechanical characteristics and making its central region a "weak" area of the vertebra. Some characteristic injuries of the vertebra are related to basivertebral foramen, such as vertebral compression fracture and intervertebral cleft, vertebral burst fracture and posterior upper vertebral fracture fragment, and cement leakage during treatment. In this article, the anatomical and developmental biological characteristics of basivertebral foramen, the impact of basivertebral foramen on biomechanical characteristics, and the treatment of basivertebral foramen related vertebral diseases are reviewed, in order to provide references for the clinical diagnosis and treatment of vertebral injuries.

Analysis of adjacent vertebral fracture after percutaneous vertebroplasty: do radiological or surgical features matter?

PURPOSE

To report the incidence and risk factors of adjacent vertebral fracture (AVF) after percutaneous vertebroplasty (PVP) in patients with osteoporotic vertebral compression fractures (OVCFs). We focused to investigate effect of radiological or surgical features on AVF.

METHODS

All patients with OVCFs who were treated with PVP between January 2016 and December 2019 were retrospectively reviewed. Patients were followed up at least 12 months after procedure according to treatment protocol. AVF was defined as postoperatively recurrent intractable back pain and subsequently presence of fracture on magnetic resonance imaging (MRI) in adjacent levels. Clinical, radiological, and surgical factors potentially affecting occurrence of AVF were recorded and analyzed using univariate and multivariate analysis.

RESULTS

Totally, 1077 patients with 1077 fractured vertebrae who underwent PVP were enrolled in the study, after inclusion and exclusion criteria were met. Mean follow-up time was 24.3 ± 11.9 months (range, 12-59 months). AVF was identified in 98 (9.1%) patients. Univariate analysis showed that seven significant factors related to AVF were older age, non-traumatic fracture, cortical disruption on anterior wall, cortical disruption on lateral wall, basivertebral foramen, type-B leakage and type-C leakage. In multivariate analysis, two clinical factors, older age (P = 0.031) and non-traumatic fracture (P = 0.002), were significantly associated with AVF. However, any radiological or surgical factor did not reach significance in final model analysis.

CONCLUSIONS

Incidence of AVF after PVP in patients with OVCFs was 9.1% (98/1077). Older age and non-traumatic fracture were two clinical risk factors for AVF. Neither radiological nor surgical feature was significantly correlated with AVF.

The incidence and risk factors for extensive epidural cement leakage in cement-augmented pedicle screw fixation: a multicenter retrospective study

INTRODUCTION

In cement-augmented pedicle screw fixation (CAPSF), epidural cement leakage (CL) is a frequently reported complication with the potential for neural injury, especially when it is extensive. To date, there has been no reports discussing basivertebral foramen morphology and pedicle screw placement, which is critical in the analysis of the risk of extensive epidural CL. Thus, this study aimed to identify the incidence and risk factors for extensive epidural CL in osteoporotic patients with CAPSF.

MATERIALS AND METHODS

371 osteoporotic patients using 1898 cement-augmented screws were included. Preoperative computed tomography (CT) was utilized to characterize basivertebral foramen morphology. Following CAPSF, the severity of epidural CL, the implantation position of pedicle screw and cement extension within the vertebral body were determined by postoperative CT. In this study, significant risk factors for extensive epidural CL were identified through logistic regression analysis.

RESULTS

There were 19 patients (5.1%) and 32 screws (1.7%) with extensive epidural CL. Nine patients (involving 19 screws) had neurological symptoms. The independent risk factors for patients with extensive epidural CL were decreased BMD and increased number of augmented screws. Significant predictors for extensive epidural CL were a magistral type of basivertebral foramen, more volume of cement injected, solid screw, a shallower screw implantation, and the smaller distance between the tip of the screw and the midline of vertebral body.

CONCLUSION

Extensive epidural CL risk was significant in CAPSF when a magistral basivertebral foramen was present; solid screws and more volume of cement were used; and screw tip was implanted shallower or closer to the midline.

Anatomic distribution of basivertebral foramen with a magistral form in vertebral bodies of T10~L5 and its clinical significance for extensive epidural cement leakage in cement-augmented pedicle screw fixation: a multicenter case-control study

BACKGROUND

There are no reports discussing anatomic distribution of basivertebral foramen (BVF) in the osteoporotic vertebral body, which is critical in the analysis of the risk of epidural cement leakage (ECL) after cement-augmented pedicle screw fixation (CAPSF).

METHODS

371 osteoporotic patients using 1898 cement-augmented screws were included. Preoperative computed tomography (CT) was used to determine the frequency, width, height, and depth of magistral BVF in T10~L5. Additionally, we measured the distance between BVF and the left/right borders of vertebral body as well as the distance between BVF and upper/lower endplates. Following CAPSF, the severity of ECL and the position of pedicle screws were determined by postoperative CT. Finally, significant risk factors for extensive ECL were identified through binary logistic regression analysis.

RESULTS

Of 2968 vertebral bodies ranging from T10 to L5, 801 (42.2%) had a magistral BVF. From T10 to L5, the frequency of magistral BVF appeared to gradually increase. The magistral BVF was much closer to the upper endplate and the depth accounted for about a quarter of anteroposterior diameter of vertebral body. Overall, there were 19 patients (5.1%) and 32 screws (1.7%) with extensive ECL, nine of whom had neurological symptoms. The independent risk factors for extensive ECL were the magistral BVF (OR = 8.62, P < 0.001), more volume of cement injected (OR = 1.57, P = 0.031), reduced distance from screw tip to vertebral midline (OR = 0.76, P = 0.003) and vertebral posterior wall (OR = 0.77, P < 0.001) respectively.

CONCLUSION

When planning a CAPSF procedure, it is important to consider anatomical distribution of BVF and improve screw implantation methods.

The Potential Impact of Basivertebral Foramen Morphology and Pedicle Screw Placement on Epidural Cement Leakage With Cement-Augmented Fenestrated Pedicle Screw Fixation: A Multicenter Retrospective Study of 282 Patients and 1404 Augmented Screws

BACKGROUND

Epidural cement leakage (CL) is a common complication in cement-augmented fenestrated pedicle screw fixation (CAFPSF) with the potential for neural injury. However, there are no reports discussing basivertebral vein morphology and pedicle screw placement, which are critical in the analysis of the risk of epidural CL after CAFPSF.

OBJECTIVE

To identify the incidence and risk factors of epidural CL in osteoporotic patients during CAFPSF.

METHODS

Two hundred and eighty-two osteoporotic patients using 1404 cement-augmented fenestrated screws were included. Preoperative computed tomography (CT) was used to characterize the morphology of posterior cortical basivertebral foramen. After CAFPSF, the severity of epidural CL, the implantation position of the screw tip, and cement extension within the vertebral body were determined by postoperative CT scans. In this study, significant risk factors for epidural CL were identified through logistic regression analysis.

RESULTS

In total, 28 patients (18.8%) and 108 screws (7.7%) had epidural CL and 7 patients (13 screws) experienced neurological symptoms. Although local epidural CL was generally not clinically significant, extensive epidural leakage posed a higher risk of neurological symptoms. Significant predictors for extensive epidural CL were a magistral type of basivertebral foramen and the smaller distance between the tip of the screw and the posterior wall of the vertebral body.

CONCLUSION

In osteoporotic patients receiving CAFPSF, epidural CL is relatively common. The morphology of basivertebral foramen should be taken into account when planning a CAFPSF procedure. It is important to try and achieve a deeper screw implantation, especially when a magistral type of basivertebral foramen is present.

Balloon kyphoplasty versus percutaneous vertebroplasty for osteoporotic vertebral body compression fractures: clinical and radiological outcomes

BACKGROUND CONTEXT

Osteoporotic vertebral body compression fracture are the commonest fractures amongst the other osteoporotic fracture sites. These fragility fractures are the result of low energy mechanical forces that that would not ordinarily result in fracture. Percutaneous vertebroplasty and balloon kyphoplasty has been widely used as minimally invasive procedures to treat painful vertebral compression fractures.

PURPOSE

Aim of the present study was to evaluate radiological, clinical and functional outcome of patients with osteoporotic vertebral body fractures treated with Balloon Kyphoplasty and Vertebroplasty.

STUDY DESIGN

Prospective cohort study PATIENT SAMPLE: 40 patients (Male:15, Female: 25) with average age of 56 +/- 8 years diagnosed with osteoporotic vertebral body compression fracture on clinical and radiological evaluation with no neurological deficit and no other associated fractures were included.

OUTCOME MEASURES

Operative time, cost for the procedure, gain in vertebral body height, reduction in pain, ability to perform daily routine activities, risk of cement leakage and any other systemic complications were evaluated and compared in both the study groups.

METHODS

All the patients underwent conventional Xray, MRI (to rule out acute from chronic fracture, to check compromise of spinal canal and calculate collapse in vertebral body height), Visual analog scaling for severity of pain and difficulty in daily routine activities by Oswestry disability index preoperatively. Post operative clinal, functional, radiological outcome and complications were compared in patients treated with percutaneous vertebroplasty and balloon kyphoplasty.

RESULT

There was significant difference in intraoperative time period and procedure cost for the patients treated with Vertebroplasty(50.75min, 25k) in comparison to balloon kyphoplasty (71.95, 50k) with p value being < .001 There was significant difference between preoperative and postoperative study parameters in both the study groups but there was no significant difference in post operative study parameters amongst both the study groups with p values >.05 for different parameters, 0.381(Gain in vertebral height), 0.108 (pain relief), 0.846(Oswestry disability index) and 0.197(risk of cement leakage) CONCLUSION: Our study suggested that percutaneous vertebroplasty requires less operative time and is more economical than balloon kyphoplasty. Increase in intraoperative time increases the risk of infection. Though the cases of Intraoperative operative cement leakage were more in percutaneous vertebroplasty but is was not significant. However the final radiological, clinical, functional outcome and overall complications were found to be similar in both the groups. Balloon kyphoplasty provided no added benefit over percutaneous vertebroplasty. A study with larger sample size will be needed to warrant one surgical procedure superior to other in the treatment of osteoporotic vertebral body compression fracture.

Systematic Retrospective Analysis of Risk Factors and Preventive Measures of Bone Cement Leakage in Percutaneous Kyphoplasty

OBJECTIVE

In this study, we aimed to analyze the risk factors of bone cement leakage in percutaneous kyphoplasty (PKP) treatment of osteoporotic vertebral compression fractures (OVCFs), and provide suggestions for reducing bone cement leakage.

METHODS

A retrospective study of 517 cases of OVCFs treated with PKP were divided into 2 groups according to whether they had bone cement leakage or not, leakage group (n = 72) and non-leakage group (n = 445). The risk factors of leakage were systematically analyzed using clinical baseline data, imaging observation data, and surgery-related factors. To select the statistically significant results (P < 0.05) among the risk factors mentioned above, we used the binary logistic regression method to identify the main risk factors.

RESULTS

The univariate analysis of clinical baseline data，imaging observation data, and surgery-related factors showed that bone mineral density (BMD) (P < 0.001), hypertension (P < 0.05), injury factors (P < 0.01), cortical defect (P < 0.001), grade of vertebral compression (P < 0.001), surgical approach (P < 0.05), stage of bone cement injection (P < 0.01), and balloon pressure (P < 0.05) were the risk factors for bone cement leakage. The recovery rate of vertebral height, and the Cobb angle correction rate were lower in the bone cement leakage group (P < 0.001). The correction effect of kyphosis after operation was limited. Binary logistic analysis results showed that BMD (odds ratio [OR] 5.605), cortical defect (OR 3.115), and stage of bone cement injection (OR 2.385) were bone cement leakage-independent risk factors.

CONCLUSIONS

Impairment of BMD value, defects of cortical bone, and inappropriate stage of bone cement injection will increase the risk of bone cement leakage in PKP treatment and limit PKP effects.

Comparison of a directional cement delivery device versus conventional device in unilateral percutaneous kyphoplasty for the therapy of osteoporotic thoracolumbar fracture in the elderly

BACKGROUND

Percutaneous kyphoplasty (PKP) has been demonstrated to be effective in the treatment of osteoporotic vertebral compression fractures (OVCF). However, bilateral puncture techniques take more time to accept more X-ray radiation; some spinal surgeons apply unilateral puncture PKP, but the cement cannot be symmetrically distributed in the vertebral body, so we apply a directional bone cement delivery device that undergoes PKP through the unilateral pedicle puncture. This research aims to compare the clinical and radiological results of PKP via unilateral pedicle approach using a traditional bone cement delivery device and a directional bone cement delivery device and determine the value of a directional delivery device for the therapy of thoracolumbar compression fracture in the elderly.

METHODS

We undertook a retrospective analysis of patients with single-level OVCF treated with unilateral pedicle puncture PKP from Jan 2018 to Jan 2020. Operation time, radiation exposure, bone cement injection volume, and the incidence of bone cement leakage were recorded for presentation, and the cement leakage and bone cement distribution were measured by X-ray and computed tomography scan. The patients were followed up postoperatively and were assessed mainly with regard to clinical and radiological outcomes.

RESULTS

There was no significant difference in the operation time, radiation exposure time, and incidence of bone cement leakage between the two groups. A significant difference was observed in the volume of bone cement injection between the two groups. All patients in both groups had significantly less pain after the procedures, compared with their preoperative period pain. There were no significant differences in Visual Analogue Scale, the relative height of the vertebral body, Cobb angle, and Quality of Life Questionnaire of the European Foundation for Osteoporosis between the two groups at 1 week after PKP, significant difference was observed only 12 months after operation.

CONCLUSION

Application of directional bone cement delivery device is safe and feasible, compared with the application of traditional bone cement delivery device, without prolonging the operative time, radiation exposure time, and the incidence of bone cement leakage. It has the advantages of good short- and medium-term effect, excellent bone cement distribution, and low incidence of kyphosis recurrence.

Continuous cement leakage along the posterior longitudinal ligament of the intraspinal epidural during a percutaneous vesselplasty: A case report and literature review

Objective

This study aims to report one case of intraspinal epidural cement leakage caused by a novel percutaneous vesselplasty.

Methods

A clinical case report from the Orthopedic center of our hospital and a literature review. A 63-year-old woman with an L₂ osteoporotic compression fracture underwent novel kyphoplasty, percutaneous vesselplasty. This rare complication was evaluated through a literature search, and its special types are classified in more detail.

Results

The patient was hospitalized with low back pain two weeks after a fall. After auxiliary examination, a new type of percutaneous vesselplasty was performed. After the intraoperative injection of bone cement, bone cement leakage extended along the posterior longitudinal ligament and epidural space. There were no special compression symptoms of the spinal cord, and the prognosis of conservative treatment was good.

Conclusion

Although percutaneous vesselplasty is relatively safe and frequent, intraspinal leakage may occur, so sufficient preoperative evaluation, intraoperative continuous fluoroscopic monitoring, and timely evaluation of postoperative images are extremely necessary.

Morphological features of basivertebral foramen among different age groups: Recognition in spine

Background

Basivertebral foramen (BF) is a vessel and nerve passage in the posterior wall of vertebral body (VB). Our goal was to report BF's morphological characteristics in different age groups of mainland Chinese adults and to evaluate the relationship between BF's morphology and factors such as age, gender, heavy work, size and level of VB.

Methods

We enrolled 300 adults among persons who came to our hospital for health examination. We measured BFs and VBs' parameters on T1 weighted sagittal lumbar spine MR images. We also assessed following potential predictors: gender, body height, body weight, body mass index, alcohol use, habits of smoking and drinking, type of work (physical work or non-physical work). A stepwise multivariate linear regression analysis was conducted to identify predictors of BF's height.

Results

People above 60 have significantly bigger BFHr than those in young adulthood and in the middle ages at all five levels, while they have shallowest BFs, especially at L3. Multiple linear regression resulted in a formula that accounted for 30.1% of the variability in the height of basivertebral foramen. Significant predictors included: gender, age, level, vertebral height and heavy work.

Conclusion

Age is the highest weight in all factors on the height of BF. BF is closer to the upper endplate. The BF was relatively higher and deeper in the female lumbar spine. Heavywork results in lower BF. Last but not the least, as we supposed, BF gets shallower and higher compare to VB with age.

Level of evidence

Prognostic level III. See instructions for authors for a complete description of levels of evidence.

A predictive nomogram for intradiscal cement leakage in percutaneous kyphoplasty for osteoporotic vertebral compression fractures combined with intravertebral cleft

BACKGROUND

For patients with osteoporotic vertebral compression fractures (OVCFs) treated with percutaneous kyphoplasty (PKP), the occurrence and risk factors of intradiscal cement leakage should be characteristic of the presence of intravertebral cleft (IVC). This study aimed to identify risk factors for intradiscal leakage in individuals with OVCFs combined with IVC treated with PKP and build a powered and well-calibrated predictive nomogram.

METHODS

This study retrospectively reviewed consecutive patients who underwent PKP at our center between January 2016 and May 2021. Patients diagnosed with OVCFs combined with IVC were identified, and the incidence of different types of bone cement leakage was recorded. Risk factors for intradiscal leakage among the demographic, perioperative baseline, and radiologic data were identified, following which a nomogram was developed and verified.

RESULTS

A total of 109 eligible patients were included, and the intradiscal leakage rate was 32.1%. Compression rate (odds ratio [OR] 0.025; 95% confidence interval [CI] 0.002-0.264; P = 0.002) and cemented vertebral body fraction (OR 44.122; 95% CI 2.790-697.740; P = 0.007) were identified as independent risk factors. A predictive nomogram with good predictive power (C-statistic = 0.786) and fitness of data (Hosmer-Lemeshow goodness-of-fit test, P = 0.092) was established to build a quantitative relationship between the risk factors and intradiscal leakage.

CONCLUSION

The incidence rate of intradiscal leakage in PKP for OVCFs combined with IVC was 32.1%. Compression rate and cemented vertebral body fraction were identified as independent risk factors. A powered and well-calibrated nomogram was established to accurately predict the probability of intradiscal leakage. Further prospective and multicenter studies are required to verify and calibrate our findings.

Establishment and Validation of a Nomogram for the Risk of New Vertebral Compression Fractures After Percutaneous Vertebroplasty in Patients With Osteoporotic Vertebral Compression Fractures: A Retrospective Study

Purpose

New vertebral compression fractures(NVCFs) after minimally invasive surgery in patients with osteoporotic vertebral compression fracture (OVCF) is a challenging issue worldwide. Predicting the occurrence of NVCFs is key to addressing such questions. Therefore, we aimed to investigate the risk factors for patients who developed NVCFs after undergoing surgical treatment and establish a nomogram model to reduce the occurrence of NVCFs.

Methods

This study is a retrospective analysis that collected the general characteristics and surgical features of patients who underwent surgical treatment at 2 central institutions between January 2017 and December 2020. Patients were divided into training and testing sets based on the presence or absence of NVCFs. Independent risk factors for NVCFs were obtained in the training set of patients, and then a nomogram model was constructed. Internal and external validation of the nomogram model was performed using the consistency index (C index), receiver operating characteristic curve(ROC), calibration curves, and decision curve analysis (DCA).

Results

A total of 562 patients were included in this study. Patients from the first center were used for nomogram construction and internal validation, and patients from the second center were used as an external validation population. Multivariate regression analysis showed that age, Hounsfield unit (Hu) value, cement leakage, and thoracolumbar (TL) junction fracture were independent risk factors for NVCFs after minimally invasive surgery. The C index was .85, and the validation of internal and external validation shows that the predicted values of the established model is in good agreement with the actual values.

Conclusions

In this study, 4 independent risk factors were obtained by regression analysis, and a nomogram model was constructed to guide clinical work. The application of this model can help surgeons to make more accurate judgments to prevent the occurrence of NVCFs.

A case report of intracardiac bone cement embolization after posterior decompression and cement-enhanced pedicle screw fixation for osteoporosis and lumbar degeneration

RATIONALE

Bone cement leakage is a common complication of percutaneous kyphoplasty (PKP) and percutaneous vertebroplasty (PVP) surgery and has also been reported in posterior decompression and cement-enhanced pedicle screw fixation. When bone cement leaks through the venous system, it will have serious consequences and even endanger the life of the patient, especially when the bone cement causes intracardiac embolism.

PATIENT CONCERNS

A 70-year-old woman developed chest tightness and decreased blood oxygen saturation following posterior decompression and cement-enhanced pedicle screw fixation.

DIAGNOSIS

After the patient was given symptomatic treatment, the symptoms were not relieved, the high-sensitivity troponin I level continued to rise, the electrocardiogram results were abnormal, and chest computed tomography (CT) revealed multiple flaky and strip-shaped dense shadows in the heart.

INTERVENTION

The patient underwent removal of foreign bodies from the heart under cardiopulmonary bypass and tricuspid valvuloplasty, removal of intracardiac bone cement, and repair of the tricuspid valve and chordae.

OUTCOME

The patient recovered well postoperatively and was discharged from the hospital after 3 weeks. There were no intracardiac foreign bodies observed on chest CT after the operation.

LESSONS

For patients with cardiopulmonary discomfort after posterior decompression and bone cement-enhanced pedicle screw fixation, in view of the limitations of radiographic examination, we recommend performing chest CT examination to confirm the diagnosis. For patients with intravascular foreign body embolism, multidisciplinary team joint treatment saves lives.

Cement-associated thrombotic embolism in the inferior vena cava and bilateral iliac veins after percutaneous vertebroplasty: a case report

Percutaneous vertebroplasty (PVP) was first reported in 1987 for treating vertebral hemangiomas. PVP is also an effective treatment for osteoporotic vertebral compression fracture that mainly involves a percutaneous injection of polymethylmethacrylate. Severe complications of PVP have been reported in recent years. However, to the best of our knowledge, cement-associated thrombotic embolism in the inferior vena cava and bilateral iliac veins after PVP has rarely been reported. We experienced a patient with cement-associated thrombotic embolism in the inferior vena cava and bilateral iliac veins after PVP. Fortunately, after conservative therapy, we achieved a satisfactory result. Unfortunately, we could not explain the cause of the cement leakage and formation of the thrombotic embolism. We believe that surgeons should have a better understanding of the fracture pattern and anatomy of the vertebral venous net system. They should also perform meticulous imaging monitoring with slower pushing of the cement to minimize the risks during the PVP. This case report highlights a rare, but potentially life-threatening, complication of PVP. Surgeons need to be aware of the possibility of cement leakage and the formation of cement-associated thrombotic embolism so that they are much more vigilant when performing PVP.

The impact of intravertebral cleft on cement leakage in percutaneous vertebroplasty for osteoporotic vertebral compression fractures: a case-control study

Background

The impact of intravertebral cleft (IVC) on cement leakage in percutaneous vertebroplasty (PVP) for osteoporotic vertebral compression fractures (OVCFs) has been discussed. However, the results were conflicting, as the study population and cement leakage classification were heterogeneous. The aim of the study was to evaluate the impact of IVC on the incidence of leakage through vein, leakage through cortex as well as general leakage in PVP for OVCFs.

Methods

All patients with OVCFs who underwent PVP between January 2016 and June 2019 at our institution were retrospectively reviewed. Patients were eligible for this case-control study if they were diagnosed as single level fracture in spine. After inclusive and exclusive criteria were met, a total of 139 patients with IVC were enrolled as the study group. Non-IVC controls were matched in a 1:1 ratio in age (within 3 years), sex and fracture severity with patients in study group. Cement leakage were classified into four types [type B (through basivertebral vein), type S (through segmental vein), type-C (through a cortical defect), and type D (intradiscal leakage)], furtherly into two types [venous type (type-B or/and type S) and cortical type (type-C or/and type-D)]. A general leakage rate and a specific leakage rate per each type were compared between both groups.

Results

Each group included 139 patients. Groups were homogenous for age, sex, fracture severity, fracture location, fracture type, cement volume, puncture approach and property of cement. Compared with control group, IVC group had a significantly lower rate of type-B (20.9% vs. 31.7%, P = 0.041), type-S (24.5% vs. 52.5%, P = 0.000), and venous type leakage (37.4% vs. 67.6%, P = 0.000), a significantly higher rate of type-C (25.9% vs. 12.2%, P = 0.004), type-D (16.5% vs. 6.5%, P = 0.009), and cortical type leakage (40.3% vs. 16.5%, P = 0.000), no significant difference on the rate of general leakage (67.6% vs. 76.3%, P = 0.109).

Conclusion

IVC decreased the risk of cement leakage through vein and increased the risk of cement leakage through cortex. However, it had no significant effect on the occurrence of general leakage.

Comparison of Cement Leakage Rate and Severity After Percutaneous Vertebroplasty for Osteoporotic Vertebral Compression Fractures Using Front-Opening Versus Side-Opening Cannulas

The authors assessed the occurrence and severity of cement leakage (CL) following percutaneous vertebroplasty (PVP) for osteoporotic vertebral compression fractures (OVCFs) performed using front-opening cannulas (FOCs) vs side-opening cannulas (SOCs). This retrospective cohort study included 811 patients with single-level OVCFs who underwent PVP between March 2016 and September 2018. The 264 patients who met the inclusion criteria were divided into two groups according to whether the procedure was performed using a FOC (n=128) or a SOC (n=136). Visual analog scale score, Oswestry Disability Index, local kyphotic angle, vertebral height, amount of bone cement injected, and rate of CL were compared between the groups. Types of CL were classified according to postoperative computed tomography. The CL types were further classified according to severity (mild and severe). Visual analog scale score, Oswestry Disability Index, local kyphotic angle, and vertebral height were all significantly improved after surgery. The total incidence of CL was significantly higher for FOCs than for SOCs (P=.001). Similarly, the occurrence of the CL subtypes was significantly higher for FOCs than for SOCs (B type, P=.033; C type, P=.01; and S type, P=.015). Analysis of CL type severity revealed that the rates of severe D type (intradiskal leakage category of the C type) and severe S type were significantly lower for SOCs than for FOCs (P=.001), while the incidence of severe B type leaks was not significantly different between the groups (P=.443). Percutaneous vertebroplasty performed using SOCs decreases the incidence and severity of D type and S type CL compared with FOCs. Secondary classification of CL could help physicians better understand the severity of leakage and select a more appropriate surgical approach to reduce CL. [Orthopedics. 2021;44(3):134-140.].

An independent inter- and intra-observer agreement assessment of Yeom classification for bone cement leakage following vertebroplasty/kyphoplasty

STUDY DESIGN

An inter- and intra-observer agreement study.

BACKGROUND

In recent years, vertebroplasty and kyphoplasty have been widely used in treating osteoporotic vertebral compression fractures (OVCF) though the clinical efficacy of them is still controversial. However, there are also inevitable complications, first and foremost is bone cement leakage (BCL). Yeom classification is commonly used to evaluate BCL. The objective of this study is to assess its reliability and reproducibility, and to explore its clinical application value.

METHODS

All 58 patients with BCL following vertebroplasty/kyphoplasty were involved. Six spine surgeons were selected to be evaluators as they were unaware of the identity of the patients and the treatment they received. They classified BCL according to Yeom system, we used kappa (K) to assess the inter- and intra-observer agreement. After 12 weeks, we repeated the analysis.

RESULTS

The inter-observer reliability of Yeom classification was substantial with K value of 0.71 (1st assessment) and 0.73 (2nd assessment). The intra-observer reproducibility of Yeom classification was near perfect with K value of 0.88.

CONCLUSION

Yeom classification system has substantial inter-observer reliability and near perfect intra-observer reproducibility in BCL following vertebroplasty/kyphoplasty, which can be widely used in clinical care as an appropriate instrument for early observation, mechanism and severity cognition, and prognosis predicting of BCL. Besides, the adding of type M (the mixed type) may improve the classification.

Basivertebral foramina of true vertebrae: morphometry, topography and clinical considerations

PURPOSE

Basivertebral foramina (BVF) are openings of the posterior wall of vertebral body (VB) that lead to basivertebral canals (BVC), where homonymous neurovascular bundle courses. BVF and BVC are implicated with spinal fractures, vertebral augmentation and basivertebral nerve radiofrequency ablation. Despite their essential clinical impact, knowledge of BVF precise anatomy is scarce. The current study describes in detail the BVF typical morphological and topographical anatomy, morphometry and variants.

METHODS

In total, 1561 dried true vertebrae of 70 Greek spines of known gender and age were examined. BVF number, location, shape and size (in foramina > 1 mm), BVF distance from VB rims and pedicles, as well as VB morphometry (diameters, heights and distance between pedicles) were studied. Ten spines were re-examined by computed tomography and BVC depth and shape were recorded. Correlations and differences were statistically analyzed.

RESULTS

C₁ lack BVF (3.4%). One BVF was found in 45.1%, two in 36.9%, three in 3.8% and four BVF in 0.6%. Multiple small (< 1 mm) foramina were observed in 10.1%. Asymmetry was detected in 12.3%. C₂ and T₁₀-L₁ presented typical pattern, whereas C₃ and T₂ had the greatest variability. BVF were significantly closer to the upper rim in C₂ and T₁₀-L₄ and to the lower rim in C₇-T₄, T₆-T₈ and L₅. The mean BVC depth was 12-21.8% of the VB anteroposterior diameter.

CONCLUSION

BVF number, shape, size and topography are described, in detail, per vertebral level. The provided morphological classification and the created cumulative BVF topographic graphs should assist in clinical practice and surgery.

Risk Factors for Cement Leakage in Percutaneous Vertebroplasty for Osteoporotic Vertebral Compression Fractures: An Analysis of 1456 Vertebrae Augmented by Low-Viscosity Bone Cement

STUDY DESIGN

Retrospective study.

OBJECTIVE

To identify risk factors for cement leakage in percutaneous vertebroplasty (PVP) using low-viscosity bone cement for osteoporotic vertebral compression fractures (OVCFs).

SUMMARY OF BACKGROUND DATA

Cement leakage is the most common complication for PVP and its risk factors have been discussed. However, data in previous series were heterogeneous. Additionally, relative smaller patient sample or more types of cement leakage classified in those studies made the results conflicting.

METHODS

A total of 1090 patients who underwent PVP with low-viscosity bone cement for OVCFs in 1456 levels between January 2016 and June 2019 were retrospectively reviewed. Parameters potentially affecting the occurrence of cement leakage were assessed using univariate and multivariate analyses. Cement leakage was assessed using postoperative computed tomography scanning, and classified into two types (cortical leakage and venous leakage) considering the mechanism.

RESULTS

The incidence of cortical and venous leakage were 20.3% (295/1456) and 56.2% (819/1456), respectively. Cortical disruption, basivertebral foramen were the strongest risk factors for cortical leakage (P = 0.000), venous leakage (P = 0.000), respectively. Greater cement volume is one risk factor for both cortical leakage and venous leakage. The intravertebral cleft, solid type of cement distribution were significant risk factors for cortical leakage, and they both were protective factors for venous leakage. For cortical leakage, older age and trauma were another two risk factors. For venous leakage, female was another one risk factor, and higher grade of fracture severity is the strongest protective factor.

CONCLUSION

Both cortical leakage and venous leakage are prevalent. Adequate known of risk factors could help balance the incidence of two type leakage in unique vertebra and reduce the incidence of leakage in general in PVP for OVCFs.Level of Evidence: 3.

Treatment of Kümmell's disease with sequential infusion of bone cement: A retrospective study

BACKGROUND

Percutaneous vertebroplasty (PVP) is an effective method for the treatment of neurologically intact Kümmell's disease, but bone cement leakage during surgery is a problem that deserves attention.

AIM

To reduce bone cement leakage and evaluate the effect of the sequential infusion of bone cement during PVP for the treatment of stage I or II Kümmell's disease.

METHODS

Patients with Kümmell's disease treated in our hospital from September 2015 to September 2018 were retrospectively analyzed. Patients meeting the inclusion and exclusion criteria were divided into two groups: Traditional single infusion and sequential infusion (SI). The visual analog scale (VAS) and Oswestry disability index (ODI) were evaluated and compared, and duration of operation, bone cement content and complications were recorded.

RESULTS

Forty-five patients were included in this study; there were 24 in the traditional single infusion group and 21 in the SI group. The VAS and ODI were significantly different for both groups when compared pre- and postoperatively, whereas the differences between 1 wk postoperatively and at the final follow-up were not statistically. When the VAS and ODI of the two groups were compared, there were no significant differences at any time point. The leakage rate of bone cement was significantly lower in the SI group (14.3%, 3 of 21) than that in the traditional single infusion group (41.7%, 10 of 24).

CONCLUSION

SI in unipedicular PVP is a safe and effective procedure for neurologically intact Kümmell's disease, and this technique could decrease the incidence of bone cement leakage.

Comparison of a flexible versus rigid bone cement injection system in unilateral percutaneous vertebroplasty

Background

Percutaneous vertebroplasty (PVP) has been demonstrated to be effective in the treatment of acute osteoporotic vertebral fracture (AOVF). However, bilateral puncture takes more time to accept more X-ray irradiation; some scholars apply unilateral puncture PVP, but the cement cannot be symmetrically distributed in the vertebral body, so we use a flexible cement injector that undergoes PVP through the unilateral pedicle puncture. This research aims to compare the clinical results of PVP for AOVF with unilateral pedicle puncture using a straight bone cement injector and a bendable cement injector, determine the value of a bendable cement injector.

Methods

We undertook a retrospective analysis of patients with thoracic and lumbar compression fracture treated with unilateral pedicle puncture percutaneous vertebroplasty from our institution from June 2013 to July 2015. Operation time, radiation exposure, bone cement injection amount, and the incidence of bone cement leakage were recorded on presentation, the cement leakage was measured by X-ray and computed tomography scan. The patients were followed up postoperatively and were assessed mainly with regard to clinical and radiological outcomes.

Results

There was no significant difference in the operation time, radiation exposure time and incidence of bone cement leakage between the two groups. There was significant difference in the amount of bone cement injection and the difference between the two groups. There were no significant differences in VAS and the relative height of the vertebral body and local Cobb angle and QUALEFFO between the two groups at 1 week after PVP, significant difference was observed only 12 months after operation.

Conclusions

Application of flexible cement injector is safe and feasible, compared with the application of straight bone cement injector, without prolonging the operative time, radiation exposure time and the incidence of bone cement leakage; it has the advantages of good long-term effect and low incidence of vertebral fracture recurrence.

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

PURPOSE

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Modified kyphoplasty with controllable balloon dilatation for treatment of thoracolumbar osteoporotic vertebral compression fractures

PURPOSE

To investigate the surgical effects of modified kyphoplasty with controllable balloon dilatation for treatment of thoracolumbar osteoporotic vertebral compression fractures (OVCF).

METHODS

From April 2013 to October 2017, a total of 53 patients with thoracolumbar OVCF were treated with controllable balloon percutaneous kyphoplasty (C-PKP). Peri-operative parameters including days from injury to operation, operation time, injected cement volume, cement leakage and complications were collected. Visual analogue scale (VAS) and Cobb angle before and after operation were applied to evaluate surgical effects. Moreover, a total of 53 cases treated with traditional balloon of percutaneous kyphoplasty were retrospectively analyzed and compared with C-PKP in above parameters.

RESULTS

C-PKP achieved significant fewer events of cement leakage (type C) than that of traditional PKP (5/53 vs 13/53, p < 0.01). The patients were followed up for 10.8 ± 4.2 months; VAS and Cobb angle of the injured vertebra in both two groups at three days and final follow-up were significantly improved compared with that before surgery (p < 0.05), while there were no significant differences between the two groups regarding the VAS and Cobb angle at corresponding time points (p > 0.05).

CONCLUSIONS

C-PKP technology is a safe and efficient way for the treatment of thoracolumbar OVCF, and it can reduce cement leakage.

Cement leakage following percutaneous kyphoplasty in a patient after a posterior lumbar fusion: a case report

BACKGROUND

Percutaneous kyphoplasty (PKP) has become an important minimally invasive surgical technique for fracture stabilization and pain relief in patients with vertebral compression fractures. However, intraspinal cement leakage following PKP is a serious postoperative complication that can lead to morbidity and mortality.

CASE PRESENTATION

We describe an uncommon case of epidural leakage of bone cement in an 81-year-old woman who underwent posterior lumbar decompression and fusion from L3-5 4 years prior and had an unremarkable postoperative course. The patient was admitted to Peking Union Medical College Hospital with complaints of muscle weakness and severe low back pain radiating to the left thigh 1 week after PKP of L5 due to an acute osteoporotic compression fracture. Computed tomographic imaging revealed massive leakage of cement into the spinal canal at L5-S1, and therefore, surgical decompression and removal of epidural cement were performed carefully without causing a dural tear. She improved remarkably and no neurologic deterioration was observed in the postoperative period during the one-year follow-up.

CONCLUSIONS

We present the rare reported case, to our knowledge, of epidural cement leakage after PKP at the segment of internal fixation and discuss the most likely etiologies and preventive measures for this condition.

Removal of intracardiac bone cement embolism after percutaneous kyphoplasty: A case report

RATIONALE

Leakage of bone cement is a common complication after percutaneous kyphoplasty. In rare cases, bone cement can leak into the venous system, which can be life threatening, especially when it causes an embolism in the heart.

PATIENT CONCERNS

A 79-year-old female patient developed chest pain with chest tightness 3 weeks after the percutaneous kyphoplasty.

DIAGNOSES

Initially, negative fluoroscopy results and elevated myocardial enzymes suggested that the patient's chest pain and chest tightness symptoms were manifestations of coronary heart disease. However, in the subsequent computed tomography (CT) examination, foreign bodies in the heart and pulmonary vessels were found.

INTERVENTIONS

The patient underwent emergency surgery to remove the bone cement and repair the tricuspid valve.

OUTCOMES

The postoperative course was uneventful and the patient was discharged on the 13th day after surgery.

LESSONS

If a patient develops chest pain with chest tightness after percutaneous kyphoplasty, the clinicians must be vigilant and take into account the limited sensitivity of fluoroscopy and use chest computer tomography and echocardiogram as the first choice and thereby prevent serious consequences.

[Clinical study of percutaneous vertebroplasty through extreme extrapedicular approach in the treatment of osteoporotic vertebral compression fracture]

Objective

To evaluate the effectiveness of percutaneous vertebroplasty (PVP) in the treatment of osteoporotic vertebral compression fracture (OVCF) through unilateral puncture of extreme extrapedicular approach and bilateral injection of bone cement.

Methods

The clinical data of 156 patients with OVCF who met the selection criteria between January 2014 and January 2016 were retrospectively analyzed. All patients were treated with PVP through unilateral puncture. According to different puncture methods, the patients were divided into two groups. In group A, 72 cases were performed PVP through the unilateral puncture of extreme extrapedicular approach and bilateral injection of bone cement, while in group B, 84 cases were performed PVP through the unilateral puncture of transpedicular approach. There was no significant difference in general data of gender, age, weight, bone mineral density, lesion segment, and disease duration between the two groups ( P>0.05). The radiation exposure time, operation time, volume of bone cement injection, rate of bone cement leakage, pre- and post-operative visual analogue scale (VAS) score and local Cobb angle were recorded and compared between the two groups.

Results

There was no significant difference in radiation exposure time and operation time between the two groups ( P>0.05), but the volume of bone cement injection in group A was significantly more than that in group B ( t=20.024, P=0.000). Patients in both groups were followed up 24-32 months (mean, 26.7 months). There were 9 cases (12.5%) and 10 cases (11.9%) of cement leakage in group A and B, respectively. There was no significant difference in the incidence ( χ ²=0.013, P=0.910). No neurological symptoms and discomfort was found in the two groups. The VAS scores of the two groups were significantly improved after operation ( P<0.05). There was no significant difference in local Cobb angle between before and after operation in group A ( P>0.05); but the significant difference was found in local Cobb angle between at 2 years after operation and other time points in group B ( P<0.05). The VAS score and local Cobb angle in group A were significantly better than those in group B at 2 years after operation ( P<0.05).

Conclusion

It is simple, safe, and feasible to use the unilateral puncture of extreme extrapedicular approach and bilateral injection of bone cement to treat OVCF. Compared with the transpedicular approach, the bone cement can be distributed bilaterally in the vertebral body without prolonging the operation time and radiation exposure time, and has an advantage of decreasing long-term local Cobb angle losing of the fractured vertebrae.

Balloon Kyphoplasty Versus Conservative Treatment for Acute Osteoporotic Vertebral Fractures With Poor Prognostic Factors: Propensity Score Matched Analysis Using Data From Two Prospective Multicenter Studies

STUDY DESIGN

A multicenter, prospective, single-arm, intervention study.

OBJECTIVE

The aim of this study was to investigate efficacy of balloon kyphoplasty (BKP) for acute osteoporotic vertebral fractures (OVFs) in patients with poor prognostic factors.

SUMMARY OF BACKGROUND DATA

The indications for BKP remain unclear. Characteristic magnetic resonance imaging (MRI) findings (high-intensity or diffuse low-intensity area in fractured vertebrae on T2-weighted images) were reportedly predictive of delayed union.

METHODS

This study enrolled 106 patients with poor prognostic MRI findings who underwent BKP within 2 months after injury, and 116 controls with acute OVFs and the same poor prognostic factors who underwent conservative treatment. Patients were propensity score matched in a logistic regression model adjusted for age, sex, number of baseline old fractures, and fracture level. The primary outcome was reduction in activities of daily living (ADLs) at 6 months after fracture, and the secondary outcomes were improvement in short-form (SF)-36 subscales, back pain visual analog scale (VAS) score, and vertebral body deformity.

RESULTS

A decrease in ADLs occurred in 5.6% of patients in the BKP group and 25.6% of patients in the conservative treatment group (P < 0.001). The SF-36 vitality subscale score improved by 26.9 ± 25.9 points in the BKP group and 14.5 ± 29.4 points in the control group (P = 0.03). The VAS pain score improved by 43.4 ± 34.4 in the BKP group and 52.2 ± 29.8 in the control group (P = 0.44). The vertebral body wedge angle improved by 5.5 ± 6.2° in the BKP group and -6.3 ± 5.0° in the control group (P < 0.0001). The percent vertebral body height improved by 15.2 ± 19.2% in the BKP group and -20.6 ± 14.2% in the control group (P < 0.0001).

CONCLUSION

ADLs, quality of life, and vertebral deformity showed greater improvement with BKP intervention for acute OVF with poor prognostic factors than with conservative treatment at 6 months after injury. Our treatment strategy uses BKP intervention according to the presence or absence of poor prognostic MRI findings.

LEVEL OF EVIDENCE

4.

Mechanism of formation of intravertebral clefts in osteoporotic vertebral compression fractures: An in vitro biomechanical study

BACKGROUND CONTEXT

Intravertebral clefts (IVCs) are vacuum-like cavities commonly associated with osteoporotic vertebral compression fractures (OVCFs). IVCs promote cement leakage during kyphoplasty, suggesting a physical link with the basivertebral foramen, although this is uncertain.

PURPOSE

The present study aims to create IVCs in mechanical experiments on cadaveric spines in order to clarify their pathogenesis, structure, and links with the basivertebral foramen.

STUDY DESIGN AND METHODS

In total, 15 three-vertebra lumbar specimens from five cadavers aged 68 to 71 years were subjected to axial compressive overload followed by cyclic loading in flexion and extension to create an OVCF together with an IVC. Computed tomography scans and radiographs were used to confirm structural changes and micro-CT was used to measure trabecular bone properties in five specimens. Unipedicular vertebroplasty was then performed on 10 damaged specimens until fluoroscopy revealed extravasation of cement.

RESULTS

In every specimen, loading created an OVCF with an IVC. Dissection and imaging showed that the IVC was always connected with the basivertebral foramen. The central vertebral region, including the IVC, had the lowest connectivity density, trabecular number, and bone volume fraction, and the highest trabecular separation. Vertebroplasty caused cement leakage through the basivertebral foramen in nine specimens and into an adjacent disc in one specimen.

CONCLUSION

Cyclic loading in flexion and extension applied to a fractured osteoporotic vertebra can create an IVC, which then allows cement leakage via the basivertebral foramen.

A modification and validation of quantitative morphometry classification system for osteoporotic vertebral compressive fractures in mainland Chinese

This study described a modified quantitative morphometry (mQM) system adapted to specific reference values for Mainland Chinese population. The mQM system is validated using the Genant Semiquantative system and is sensitive for detecting vertebral height changes and predicting cement leakage after percutaneous kyphoplasty (PKP) in patients with osteoporotic vertebral compressive fracture (OVCF).

INTRODUCTION

OVCF is a manifestation of osteoporosis. To improve clinical management of osteoporosis, the quantitative morphometry (QM) system has been widely used for the early diagnosis and precise classification of OVCF in developed countries. Here, we present an mQM system and validated its use in detecting OVCF in Mainland Chinese.

METHODS

Using our mQM system, the pre- and post-operative values of vertebral heights were measured and evaluated in 309 Mainland Chinese who received percutaneous kyphoplasty (PKP) as OVCF treatment. Measurements and classification of fractures from the mQM system were validated by comparing to values obtained by the Genant semiquantative (SQ) method. Moreover, we evaluated the sensitivity of the mQM system by its ability to detect restoration of vertebral heights and predict cement leakage after PKP.

RESULTS

The five classification of fractures, No deformity (ND), anterior wedge (AW), posterior wedge (PW), biconcavity (BC), and compression (CP), evaluated by the mQM method shared similar distribution characteristics compared to those obtained by the SQ method. In addition, mQM evaluation showed that the vertebra height of all fracture types showed significant restoration after PKP. The incidence of cement leakage was most common in CP (37.5%), followed by AW (31.6%), BC (26.5%), ND (23.7%), and PW (0.0%).

CONCLUSIONS

Our mQM system is suitable for classification of fractures, detection of vertebral height restoration, and correlation of cement leakage after PKP in Mainland Chinese population.

The mechanism of thoracolumbar burst fracture may be related to the basivertebral foramen

BACKGROUND CONTEXT

The basivertebral foramen (BF), located in the middle posterior wall of the vertebral body, may induce local weakness and contribute to the formation of a retropulsed bone fragment (RBF) in thoracolumbar burst fracture (TLBF). We hypothesize that the mechanism of TLBF is related to the BF.

PURPOSE

This study aimed to clarify the relationship between RBFs and the BF in TLBFs, and to explain the results using biomechanical experiments and micro-computed tomography (micro-CT).

STUDY DESIGN

A comprehensive research involving clinical radiology, micro-CT, and biomechanical experiments on cadaveric spines was carried out.

PATIENT SAMPLE

A total of 162 consecutive patients diagnosed with TLBF with RBFs, drawn from 256 patients who had reported accidents or injuries to their thoracolumbar spine, comprised the patient sample.

OUTCOME MEASURES

Dimensions and location of the RBFs in relation to the BF were the outcome measures.

MATERIALS AND METHODS

Computed tomography reconstruction imaging was used to measure the dimensions and location of RBFs in 162 patients (length, height, width of RBF and vertebral body). Furthermore, micro-CT scans were obtained of 10 cadaveric spines. Each vertebral body was divided into three layers (superior, middle, and inferior), and each layer was divided further into nine regions (R1-R9). Microarchitecture parameters were calculated from micro-CT scans, including bone volume fraction (BV/TV), connectivity (Conn.D), trabecular number (Tb.N), trabecular thickness (Tb.Th), and bone mineral density (BMD). Differences were analyzed between regions and layers. Burst fractures were simulated on cadaveric spines to explore the fracture line location and test the relationship between RBFs and BF.

RESULTS

Retropulsed bone fragment width was usually one-third of the width of the vertebral body, whereas RBF length and height were approximately half of the corresponding vertebral body dimensions. Measures of trabecular bone quality were generally lowest in those central and superior regions of the vertebral body which are adjacent to the BF and which are most affected by burst fracture. In simulated TLBFs, the fracture line went across the vertex or upper surface of the BF.

CONCLUSIONS

The most vulnerable regions in the vertebral body lie within or just superior to the BF. The central MR2 region in particular is at risk of fracture and RBF formation.

[Effectiveness comparison between unilateral and bilateral percutaneous kyphoplasty for Kümmell disease]

Objective

To compare the effectiveness between unilateral and bilateral percutaneous kyphoplasty (PKP) in the treatment of Kümmell disease.

Methods

The clinical data of 45 patients with Kümmell disease that met the criteria between January 2014 and February 2016 were analyzed retrospectively. Among them, 26 cases were treated by unilateral PKP (unilateral group), 19 cases were treated by bilateral PKP (bilateral group). There was no significant difference in gender, age, disease duration, injured vertebral segment, bone mineral density (T value), and the preoperative visual analogue scale (VAS) score, Oswestry disability index (ODI), anterior vertebral height, and kyphosis Cobb angle between 2 groups ( P>0.05). The operation time, intraoperative fluoroscopy times, amount of injected bone cement, and hospitalization time were recorded, and the situation of bone cement leakage was observed. The VAS score, ODI, anterior vertebral height, and kyphosis Cobb angle were evaluated before operation, at 1 day after operation, and at last follow-up.

Results

Bone cement leakage during the operation were found in 4 cases (15.38%) of unilateral group and 3 cases (15.79%) of bilateral group without obvious neurological symptoms; there was no significant difference in the incidence of bone cement leakage between 2 groups ( χ2=0.000, P=1.000). The operation time, intraoperative fluoroscopy times, and amount of injected bone cement in the unilateral group were significantly lower than those in the bilateral group ( P<0.05); but there was no significant difference in the hospitalization time between 2 groups ( P>0.05). The X-ray film examination showed that there was no pulmonary embolism in all patients at 1 day after operation. All the patients were followed up 12-24 months, with an average of 16.4 months. There was no complication such as vertebral re-fracture or cement block displacement in the injured vertebra. The VAS score, ODI, anterior vertebral height, and kyphosis Cobb angle at 1 day after operation and at last follow-up were significantly improved when compared with preoperative values in 2 groups ( P<0.05); the VAS score and ODI in 2 groups were further reduced at last follow-up when compared with the value at 1 day after operation ( P<0.05), but the anterior vertebral height and kyphosis Cobb angle in 2 groups at last follow-up did not change significantly ( P>0.05). There was no significant difference in above indexes at 1 day after operation and at last follow-up between 2 groups ( P>0.05).

Conclusion

Both unilateral and bilateral PKP can achieve good effectiveness in treatment of Kümmell disease. But the unilateral puncture technique possesses advantages such as shorter operation time, less radiation dose, and less amount of injected bone cement.

Trabecular Microstructure and Damage Affect Cement Leakage From the Basivertebral Foramen During Vertebral Augmentation

STUDY DESIGN

A prospective study on cadaver specimens.

OBJECTIVE

To explore why cement leakage from basivertebral foramen (BF) easily occurs during vertebral augmentation procedures.

SUMMARY OF BACKGROUND DATA

Type B (through BF, basivertebral foramen) cement leakage is the most common type after vertebral augmentation, but the mechanism of this is still controversial. The contribution of vertebral trabecular bone orientation and trabecular damage during compression fracture to cement leakage is still unknown.

METHODS

In this study, 12 fresh-frozen human lumbar spines (T12-L5) were collected and divided into 24 three-segment units. Mechanical testing was performed to simulate a compression fracture. MicroCT were performed on all segments before and after mechanical testing, and trabecular microstructure of the superior, middle (containing BF), and inferior 1/3 of each vertebral body was analyzed. The diameter variation of intertrabecular space before and after compression fracture was used to quantify trabecular injury. After mechanical testing, vertebral augmentation, and imaging-based diagnosis were used to evaluate cement leakage.

RESULTS

Trabecular bone microstructural parameters in middle region (containing BF) were lower than those of the superior or inferior regions (P < 0.01). After compressive failure, 3D-reconstruction of the vertebral body by MicroCT demonstrated that intertrabecular distance in the middle region was markedly increased. Type B cement leakage was the most common type after vertebral augmentation, as found previously in Wang et al. (Spine J 2014;14: 1551-1558).

CONCLUSION

The presence of the BF and the relative sparsity of trabecular bone make the middle region of the vertebral body the mechanically weakest region. Trabecular bone in middle region suffered the most severe damage during compressive failure of the vertebral body, which resulted in the greatest intervertebral spacing, and subsequently the highest percentage of type B cement leakage. These data suggest specific mechanisms by which cement may leak from the BF, and the contribution of trabecular microstructure and trabecular injury.

LEVEL OF EVIDENCE

4.

Potential risks of using cement-augmented screws for spinal fusion in patients with low bone quality

BACKGROUND CONTEXT

Dramatic increases in the average life expectancy have led to increases in the variety of degenerative changes and deformities observed in the aging spine. The elderly population can present challenges for spine surgeons, not only because of increased comorbidities, but also because of the quality of their bones. Pedicle screws are the implants used most commonly in spinal surgery for fixation, but their efficacy depends directly on bone quality. Although polymethyl methacrylate (PMMA)-augmented screws represent an alternative for patients with osteoporotic vertebrae, their use has raised some concerns because of the possible association between cement leakages (CLs) and other morbidities.

PURPOSE

To analyze potential complications related to the use of cement-augmented screws for spinal fusion and to investigate the effectiveness of using these screws in the treatment of patients with low bone quality.

STUDY DESIGN

A retrospective single-center study.

PATIENT SAMPLE

This study included 313 consecutive patients who underwent spinal fusion using a total of 1,780 cement-augmented screws.

METHODS AND OUTCOME MEASURES

We analyzed potential complications related to the use of cement-augmented screws, including CL, vascular injury, infection, screw extraction problems, revision surgery, and instrument failure. There are no financial conflicts of interest to report.

RESULTS

A total of 1,043 vertebrae were instrumented. Cement leakage was observed in 650 vertebrae (62.3%). There were no major clinical complications related to CL, but two patients (0.6%) had radicular pain related to CL at the S1 foramina. Of the 13 patients (4.1%) who developed deep infections requiring surgical debridement, two with chronic infections had possible spondylitis that required instrument removal. All patients responded well to antibiotic therapy. Revision surgery was performed in 56 patients (17.9%), most of whom had long construction. A total of 180 screws were removed as a result of revision. There were no problems with screw extraction.

CONCLUSIONS

These results demonstrate the efficacy and safety of cement-augmented screws for the treatment of patients with low bone mineral density.

Is There a Dose-Response Relationship of Cement Volume With Cement Leakage and Pain Relief After Vertebroplasty?

The aim of this study was to determine if there were dose–response relationships of cement volume with cement leakage and pain relief after percutaneous vertebroplasty (PVP) for osteoporosis vertebral compression fractures (OVCFs). We collected the patient and procedural characteristics on 108 patients with OVCFs in our hospital who received PVP. Univariate and multivariate analyses were performed to explore the relationships between these potential influential variables and cement leakage and pain relief at 1 month postoperatively. Multivariate linear and logistic regression analyses were conducted with the pain score reduction and the bone cement leakage as dependent variables and the potential risk factors as independent variables, respectively. The results showed that the independent risk factors for the pain relief were the cement volume injected and fracture age, and for bone cement leakage were the cement volume injected and low-viscosity cement. In conclusion, the present study indicated that there were positive dose–response correlation relationships of cement volume with the incidence of cement leakage and the degree of pain relief after PVP, respectively. Thus, the cement should be injected into the vertebrae as much as possible during the PVP procedure.

New Landmark for Localizing the Site of the Subdental Synchondrosis Remnant: Application to Discerning Pathology from Normal on Imaging

OBJECTIVE

We hypothesized that the entry site of the basivertebral vein into the basivertebral foramen of C2 might localize the subdental synchondrosis between the odontoid process and body of C2, which may be helpful for odontoid fracture classification.

METHODS

Twenty-five dry adult C2 specimens underwent thin-cut computed tomography and were sectioned sagittally. The basivertebral foramen was then correlated to internal bony anatomy. Fifty magnetic resonance images were reviewed, and the location of the subdental synchondrosis was determined.

RESULTS

A basivertebral foramen was identified on the posterior surface of all dry C2 specimens. The openings were found at a distance of 30%-44% on an inferosuperior point along the vertical height of C2. For bony specimens with a subdental synchondrosis remnant (75%), entry of acupuncture needles into the basivertebral foramen was always directly at the level of the synchondrosis remnant. For magnetic resonance imaging (MRI), a subdental synchondrosis or its remnants were seen on all studies. The distance from the base of C2 to the subdental synchondrosis ranged from 9-13 mm. This equated to an inferosuperior point 32%-43% along the vertical height of C2. A strong correlation existed when comparing the location of the basivertebral foramen of bony specimens and the subdental synchondrosis location on MRI.

CONCLUSIONS

The basivertebral foramen is a consistently present anatomic reference point for the subdental synchondrosis even if the latter cannot be seen on conventional radiographic imaging. Our MRI data might also be useful in helping differentiate lesions affecting C2 from normal subdental cartilaginous remnants that can be encountered on imaging.