Percutaneous vertebral augmentation procedures in the management of spinal metastases

Improved localization and segmentation of spinal bone metastases in MRI with nnUNet radiomics

Objective

Variability exists in the subjective delineation of tumor areas in MRI scans of patients with spinal bone metastases. This research aims to investigate the efficacy of the nnUNet radiomics model for automatic segmentation and identification of spinal bone metastases.

Methods

A cohort of 118 patients diagnosed with spinal bone metastases at our institution between January 2020 and December 2023 was enrolled. They were randomly divided into a training set (n = 78) and a test set (n = 40). The nnUNet radiomics segmentation model was developed, employing manual delineations of tumor areas by physicians as the reference standard. Both methods were utilized to compute tumor area measurements, and the segmentation performance and consistency of the nnUNet model were assessed.

Results

The nnUNet model demonstrated effective localization and segmentation of metastases, including smaller lesions. The Dice coefficients for the training and test sets were 0.926 and 0.824, respectively. Within the test set, the Dice coefficients for lumbar and thoracic vertebrae were 0.838 and 0.785, respectively. Strong linear correlation was observed between the nnUNet model segmentation and physician-delineated tumor areas in 40 patients (R 2 = 0.998, P < 0.001).

Conclusions

The nnUNet model exhibits efficacy in automatically localizing and segmenting spinal bone metastases in MRI scans.

Safety and clinical efficacy of microwave ablation combined with percutaneous vertebroplasty in the treatment of multisegmental spinal metastases

OBJECTIVE

To evaluate the safety and efficacy of microwave ablation (MWA) combined with percutaneous vertebroplasty (PVP) in the treatment of multisegmental (2-3 segments) osteolytic spinal metastases.

MATERIALS AND METHODS

This study comprised a retrospective analysis of data from 20 patients with multisegmental (2-3 segments) osteolytic spinal metastases who received MWA combined with PVP. The visual analog scale (VAS) score, Oswestry Disability Index (ODI) score, Quality of Life Questionnaire-Bone Metastases 22 (QLQ-BM22), and local recurrence before and after the operation were measured. The occurrence of complications was observed to evaluate safety.

RESULTS

All operations were completed successfully with no serious complications. Transient nerve injury occurred in two cases, but recovered after symptomatic treatment. The bone cement leakage rate was 13.9% (6/43). The mean baseline VAS scores were 7.25 ± 0.91 before treatment and 7.25 ± 0.91, 3.70 ± 1.12, 2.70 ± 0.73, 2.40 ± 0.68, 2.25 ± 0.71, and 2.70 ± 0.92 at 1 day, 1 week, 1, 3, and 6 months after treatment; all values were significantly lower (P < 0.001). The mean baseline ODI score decreased from 56.90 ± 9.74 before treatment to 41.90 ± 7.09, 38.10 ± 7.93, and 38.80 ± 10.59 at 1, 3, and 6 months after treatment, respectively; all values were significantly lower (P < 0.001). The average QLQ-BM22 baseline score decreased from 54.10 ± 5.36 before treatment to 44.65 ± 5.22, 43.05 ± 4.78, 42.30 ± 4.06, and 42.15 ± 5.47 at 1 week, 1, 3, and 6 months after treatment; all values were significantly lower (all P < 0.001). The postoperative survival time of all patients was >6 months. In three patients, four vertebral segments recurred 6 months after operation.

CONCLUSION

MWA combined with PVP is a safe and effective treatment for multisegmental osteolytic vertebral metastases that can effectively relieve pain, improve spinal function, improve quality of life, and delay tumor progression. However, it is a long operation, necessitating good preoperative preparation and effective intraoperative pain relief measures.

Modified Total en Bloc Spondylectomy with Self-Made Intervertebral Hook Blade in Spinal Tumors: A Retrospective Study

OBJECTIVE

Total en bloc spondylectomy (TES) is an important surgical treatment for spinal tumors that can achieve en bloc resection of the affected vertebral body by using the T-saw. However, the conventional TES process and the surgical instruments currently in use have some inconveniences, which may lead to longer operative times and a higher incidence of complications. To address these obstacles, we developed a modified TES technique using a homemade intervertebral hook blade. The objectives of this study were to describe our modified total en bloc spondylectomy (TES) using a homemade intervertebral hook blade and to assess its clinical effects in patients with spinal tumors.

METHODS

Twenty-three consecutive patients with spinal tumors were included from September 2018 to November 2021. Eleven patients underwent a modified TES using an intervertebral hook blade, and 12 patients underwent a conventional TES using a wire saw. Details of the modified technique for TES were depicted, and the intraoperative blood loss, operative time, and improvement in pain symptom and neurological function measured by visual analog score (VAS) and American Spinal Injury Association (ASIA) score of all patients was reviewed and analyzed. Nonparametric analysis of covariates (ANCOVA) was performed to compare the clinical outcomes between patients treated with modified TES and conventional TES.

RESULTS

The modified TES significantly reduced operative time (F = 7.935, p = 0.010) and achieved favorable improvement of neurological function (F = 0.570, p = 0.459) and relief of pain (F = 3.196, p = 0.088) compared with the conventional TES group. The mean intraoperative blood loss in the modified TES group (2381.82 ml) was lower than that in the conventional TES group (3558.33 ml), although the difference was not statistically significant (F = 0.677, p = 0.420).

CONCLUSIONS

Modified TES using the intervertebral hook blade can effectively reduce the operation time and intraoperative bleeding, and meanwhile ensure the improvement of neurological function and relief of pain symptoms, suggesting that this modified technique is feasible, safe, and effective for spinal tumors.

Balloon kyphoplasty as palliative care for painful pathological spinal fracture followed by lung cancer metastasis: A cohort study

Background

Pathological spine fractures caused by metastases of lung cancer have brought great suffering to patients. Percutaneous kyphoplasty (PKP) has been considered a preferred alternative for painful spinal metastases. The clinical efficacy and safety of PKP for metastatic spinal lesions are urgently to be evaluated.

Methods

A cohort study was conducted on 54 cases with pathologic spine fractures caused by metastasis of lung cancer. The correction of kyphosis was assessed by the Cobb angle. The life dependence and quality of the patients were evaluated by the Barthel Index of activities of daily living (ADL) and the quality-adjusted life year (QALY). Patients' survival was carefully recorded.

Results

PKP significantly corrected the kyphosis compared with conservative treatment. The ratio of moderate dependence after fracture was clearly increased by PKP. QALY indicated a better life quality brought by PKP. However, PKP could not improve the survival rate of patients.

Conclusion

PKP can be used as an effective palliative care treatment for patients with metastatic pathologic spinal fractures of lung cancer.

Surgical robot-assisted tripod percutaneous reconstruction technique combined with bone cement filling technique for the treatment of acetabular metastasis

Background: Acetabular metastasis is a type of metastatic bone cancer, and it mainly metastasizes from cancers such as lung cancer, breast cancer, and renal carcinoma. Acetabular metastasis often causes severe pain, pathological fractures, and hypercalcemia which may seriously affect the quality of life of acetabular metastasis patients. Due to the characteristics of acetabular metastasis, there is no most suitable treatment to address it. Therefore, our study aimed to investigate a novel treatment technique to relieve these symptoms. Methods: Our study explored a novel technique to reconstruct the stability of the acetabular structure. A surgical robot was used for accurate positioning and larger-bore cannulated screws were accurately inserted under the robot's guidance. Then, the lesion was curetted and bone cement was injected through a screw channel to further strengthen the structure and kill tumor cells. Results: A total of five acetabular metastasis patients received this novel treatment technique. The data relating to surgery were collected and analyzed. The results found that this novel technique can significantly reduce operation time, intraoperative bleeding, visual analogue score scores, Eastern Cooperative Oncology Group scores, and postoperative complications (e.g., infection, implant loosening, hip dislocation) after treatment. Follow-up time ranged from 3 months to 6 months, and the most recent follow-up results showed that all patients survived and no acetabular metastasis progressed in any of the patients after surgery. Conclusion: Surgical robot-assisted tripod percutaneous reconstruction combined with the bone cement filling technique may be a novel and suitable treatment in acetabular metastasis patients. Our study may provide new insights into the treatment of acetabular metastasis.

PVP with or without microwave ablation for the treatment of painful spinal metastases from NSCLC: a retrospective case-control study

OBJECTIVE

To compare the clinical efficacy of percutaneous vertebroplasty (PVP) alone and microwave ablation (MWA) combined with PVP for the treatment of painful spinal metastases from non-small cell lung cancer (NSCLC).

METHODS

From October 2014 to October 2021, the data of 58 NSCLC patients with refractory painful spinal metastases (visual analog scale score ≥ 5) were retrospectively collected and analyzed. Patients in Group A (n = 30) and Group B (n = 28) received PVP alone and MWA combined with PVP, respectively. The primary endpoint was pain relief. The secondary endpoints were quality of life (QoL), local tumor progression (LTP), and complications.

RESULTS

The technical success rate was 100% in both groups. Patients in both groups showed similar pain relief at 1-12 weeks, but patients in Group B still showed sustained pain relief at 24 weeks compared to those in Group A (p = 0.03). The assessment of QoL showed similar changes. LTP (33.00% vs. 7.14%, p = 0.02) and cement leakage rates (40.00% vs. 7.14%, p = 0.03) were lower in Group B. The multivariate analysis demonstrated spinal metastases with a maximum diameter ≤ 3.0 cm (p = 0.027) and MWA combined with PVP (p = 0.028) were two independent protective factors for LTP. For cement leakage, spinal metastases with vertebral body compression (p = 0.019) was an independent risk factor, while MWA combined with PVP (p = 0.042) was an independent protective factor.

CONCLUSION

MWA combined with PVP for painful spinal metastases from NSCLC performed more sustained pain relief (>6 months) and ultimately improved QoL with lower LTP and cement leakage rates, compared to PVP alone.

Prognostic Factors for Bone Survival and Functional Outcomes in Patients With Breast Cancer Spine Metastases

According to the Global Cancer Statistics 2020 report, breast cancer is the most commonly diagnosed cancer worldwide. Patients with mammary cancer live longer due to the continuous optimization of chemotherapy, targeted drugs, and hormone therapy, which will inevitably lead to an increase in the prevalence of metastatic bone tumors. Bone metastasis affects approximately 8% of patients with mammary cancer, with the spine being the most common site. Metastatic neoplasms can invade the centrum and its attachments, leading to local pain, spinal instability, vertebral pathological fractures, spinal cord compression, impaired neurological function, and paralysis, ultimately reducing the quality of life. Multidisciplinary and personalized management using analgesic drugs, endocrine therapy, corticosteroid therapy, chemotherapy, bisphosphonates, immunotherapy, targeted drugs, radiotherapy, and surgery has been advocated for the treatment of spinal metastases. Multiple paradigms and systems have been proposed to determine suitable treatments. In the early stages, the occurrence of metastasis indicates a terminal stage of the tumor process in patients with malignant tumors, implying that their lifespan is limited. As a result, the choice of treatment is heavily influenced by longevity. However, with the development of treatment methods, the lifespan of patients with tumors has considerably increased in recent years. This leads to the choice of patient's treatment, which depends not only on the patient's survival, but also on the radiotherapy or postoperative functional outcomes. Nevertheless, they fall short of determining the variables that affect survival and functional outcomes in histology-specific subgroups of breast cancer. To accurately predict the bone survival and functional outcomes of patients with breast cancer spine metastases a review of prognostic factors was performed.

Bone Cement and Pedicle Screw for the Treatment of Spinal Tumors with Spinal Cord Compression and Posterior Wall Defects

OBJECTIVE

To compare the safety and efficacy of posterior internal fixation with open vertebroplasty (VP) and posterior internal fixation with open kyphoplasty (KP) in the treatment of metastatic epidural spinal cord compression (MESCC) with posterior wall destruction.

METHODS

This retrospective study, conducted between January 2016 and May 2019, equally divided 60 patients with MESCC and posterior wall destruction into two groups based on the surgical method: open vertebroplasty with pedicle screw fixation (VP group) and open kyphoplasty with pedicle screw fixation (KP group). Visual analogue scale (VAS), SF-36 scores, middle vertebral height (MVH), and posterior vertebral height (PVH) were evaluated for the two groups preoperatively, postoperatively, and 1 year after surgery. Spinal Instability Neoplastic Score, Frankel grades and complications were recorded and evaluated.

RESULTS

Five patients were excluded from the analysis, and our study cohort consisted of 55 adult patients who met the inclusion criteria. The VAS and SF-36 scores of these two groups of patients significantly improved, when compared with those before the surgery (P < 0.05). There were significant differences in total cost (8835 ± 1468 vs 9540 ± 053 USD) and cement volume (4.51 ± 0.96 ml vs 6.35 ± 1.09 ml) between two groups (P < 0.05). The MVH and PVH of these two groups of patients significantly improved, when compared with those before the surgery (P < 0.05). The MVH was significantly larger in the KP group than in the VP group postoperatively (20.15 ± 4.86 vs 17.70 ± 3.78, P < 0.05) and at the final follow-up (20.42 ± 5.59 vs 17.28 ± 3.23, P < 0.05). However, the PVH of the two groups did not significantly differ at the two postoperative follow-ups (P > 0.05). No significant differences were found in surgery time, time from surgery to discharge, blood loss and complications between both groups postoperatively (P > 0.05).

CONCLUSION

In the short term, both approaches are effective and safe in patients with MESCC and posterior wall destruction. The posterior internal fixation with open VP may be a good choice of surgical method in patients with MESCC and posterior wall defects.

Minimally Invasive Interventional Procedures for Metastatic Bone Disease: A Comprehensive Review

Metastases are the main type of malignancy involving bone, which is the third most frequent site of metastatic carcinoma, after lung and liver. Skeletal-related events such as intractable pain, spinal cord compression, and pathologic fractures pose a serious burden on patients’ quality of life. For this reason, mini-invasive treatments for the management of bone metastases were developed with the goal of pain relief and functional status improvement. These techniques include embolization, thermal ablation, electrochemotherapy, cementoplasty, and MRI-guided high-intensity focused ultrasound. In order to achieve durable pain palliation and disease control, mini-invasive procedures are combined with chemotherapy, radiation therapy, surgery, or analgesics. The purpose of this review is to summarize the recently published literature regarding interventional radiology procedures in the treatment of cancer patients with bone metastases, focusing on the efficacy, complications, local disease control and recurrence rate.

The role of percutaneous vertebral augmentation in patients with metastatic breast cancer: Literature review including report of two cases

Patients with metastatic breast cancer are at high risk for developing vertebral compression fractures due to underlying bone metastases and bone density loss. Vertebral augmentation techniques including percutaneous vertebroplasty and percutaneous balloon kyphoplasty are techniques used to stabilize compression fractures and improve pain. However, rare complications from these interventions have been observed, including spinal cord compression, nerve root compression, venous cement embolism, and pulmonary cement embolism. These complications pose unique potential challenges for patients with cancer who may already have decreased lung function and potential for venous thromboembolism. In this review, we first describe the role of percutaneous vertebral augmentations in patients with metastatic cancer, with a particular focus on patients with breast cancer. Then, we describe complications of vertebral augmentation in two patients with metastatic breast cancer including long-term symptomatic and radiographic follow-up.

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Balloon kyphoplasty and percutaneous vertebroplasty are used to stabilize compression fractures and improve pain.

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Leakage of bone cement can cause cement emboli which can depsit in locations such as the pulmonary and renal vasculature.

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Management of cement emboli depends on the amount of cement embolized and the severity of symptoms.

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Future studies are needed to better understand the long-term radiographic and clinical consequences of cement emboli.

Life-threatening intracardiac cement embolisms after percutaneous kyphoplasty: a case report and literature review

BACKGROUND

Percutaneous kyphoplasty is a popular technique in the treatment of osteoporotic vertebral fractures, but intracardiac cement embolism can be a life-threatening complication.Case presentation: The authors present a case involving a patient who developed dyspnea and chest tightness after percutaneous kyphoplasty. Echocardiography and chest computed tomography confirmed several foreign bodies in the right atrium and pulmonary arteries causing cardiac perforation and pericardial tamponade. Conservative treatment was administered, and the patient died of respiratory and heart failure.

CONCLUSIONS

The present case highlights that surgical removal may be the first-choice treatment for symptomatic intracardiac cement embolism.

Interventional Management of Painful Vertebral Body Metastases

Management of osseous metastatic disease has advanced over the years with the advent of ablation and interventional technologies. Painful metastatic vertebral body lesions have been particularly studied in the recent years, as open surgery is usually reserved for emergent cord compression. Minimally invasive options in managing these lesions include percutaneous vertebral augmentation, percutaneous ablation, and embolization. This article will include an overview of these procedures including the most recent literature.

National trends in the surgical management of metastatic lung cancer to the spine using the national inpatient sample database from 2005 to 2014

Optimal management of metastatic lung cancer to the spine (MLCS) incorporates a multidisciplinary approach. With improvements in lung cancer screening andnonsurgical treatment, the role for surgerymay be affected. The objective of this study is to assess trends in the surgical management of MLCS using the National Inpatient Sample (NIS) database. The NIS was queried for patients with MLCS who underwent surgery from 2005 to 2014. The frequencies of spinal decompression alone, spinal stabilization with or without (+/-) decompression, and vertebral augmentation were calculated. Statistical analysis was performed to analyze the effect of patient characteristics on outcomes. The most common procedure performed was vertebral augmentation (10719, 44.3%), followed by spinal stabilization +/- decompression (8634, 35.7%) and then decompression alone (4824, 20.0%). The total number of surgeries remained stable, while the rate of spinal stabilizations increased throughout the study period (p < 0.001). Invasive procedures such as stabilization and decompression were associated with greater costs, length of stay,complications and mortality. Increasingcomorbidity was associated with increased odds of complication, especially in patients undergoing more invasive procedures. In patients with lowpre-operative comorbidity, the type of procedure did not influence the odds of complication. Graded increases in length of stay, cost and mortality were seen with increasing complication rate.The rate of spinal stabilizations increased, which may be due to either increased early detection of disease facilitating use of outpatient vertebral augmentation procedures and/or the recognition that surgical decompression and stabilization are necessary for optimal outcome in the setting of MLCS with neurological deficit.

Current trends in incidence, characteristics, and surgical management of metastatic breast cancer to the spine: A National Inpatient Sample analysis from 2005 to 2014

Management of metastatic breast cancer to the spine (MBCS) incorporates a multimodal approach. Improvement in screening and nonsurgical therapies may alter the trends in surgical management of MBCS. The objective of this study is to assess trends in surgical management of MBCS and short-term outcomes based on the National Inpatient Sample (NIS) database. The NIS database was queried for patients with MBCS who underwent surgery from 2005 to 2014. The weighted frequencies of spinal decompression alone, spinal stabilization +/- decompression, and vertebral augmentation were calculated. Multivariate analysis was performed to analyze the effect of patient characteristics on outcomes stratified by procedure. The most common procedure performed was vertebral augmentation (11,114, 53.4%), followed by stabilization +/- decompression (6,906, 33.2%) and then decompression alone (3,312, 13.4%). The total population-adjusted rate of surgical management for MBCS remained stable, while the rate of spinal stabilization increased (P < 0.001) and vertebral augmentation decreased (p < 0.003). The risk of complication increased with spinal stabilization and decompression compared to vertebral augmentation procedures in those with fewer comorbidities. This relative increase in risk abated in patients with higher numbers of pre-operative comorbidities. Any single complication was associated with increases in length of stay, cost, and mortality. The rate of in-hospital interventions remained stable over the study period. Stratified by procedure, the rate of stabilizations increased with a concomitant decrease in vertebral augmentations, which suggests that patients who require hospitalization for MBCS are becoming more likely to represent advanced cases that are not amenable to palliative vertebral augmentation procedures.

Iodine-125 radioactive seed brachytherapy as a treatment for spine and bone metastases: A systematic review and meta-analysis

AIM

To evaluate the analgesic efficacy, safety, and local tumor control of iodine-125 (¹²⁵I) seed brachytherapy (BT) for the management of spine and bone metastases.

METHODS

A systematic literature search was conducted using PubMed, the Cochrane Library, and Scopus databases. Data regarding patient demographics, tumor characteristics, procedural parameters, and clinical outcomes were extracted and analyzed.

RESULTS

Fourteen studies (7 prospective, 7 retrospective) were included, accounting for 689 patients, in our review. Analgesic efficacy was assessed at baseline and various postoperative time points. Significant improvement in pain was noted at 4- and 24-week follow-ups (p < 0.01). Interestingly, all studies that combined ¹²⁵I seed BT with cement augmentation reported relatively higher levels of pain reduction (mean pain reduction ≥4 points) as compared to the studies which applied ¹²⁵I seed BT as a stand-alone therapy (mean pain reduction ≥2 points), at the last follow-up. Local tumor control rates ranged widely from 14% to 100% at varying follow-ups. Median overall survival ranged between 10 months and 25 months. The overall complication rate was 19% (130/689) and mainly included minor subcutaneous hemorrhage, fever, myelosuppression, and seed displacement. Metrics assessing performance and quality of life demonstrated significant improvements from baseline to posttreatment.

CONCLUSION

¹²⁵I seed BT, alone or in conjunction with cement augmentation, may be a viable salvage therapy in appropriately selected patients. However, further studies are needed to analyze the long-term efficacy of this intervention as a palliative and curative modality.

Epidemiology and detection of cement leakage in patients with spine metastases treated with percutaneous vertebroplasty: A 10-year observational study

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Cement leak is common for percutaneous vertebroplasty in metastatic spinal disease.

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A proposed and validated algorithm can screen patients with high cement leak risk.

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The algorithm included four significant characteristics.

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The validation group AUROC was 0.69, and the goodness-of-fit test P-value was 0.50.

Objectives

To investigate the epidemiology of cement leaks and further develop an algorithm to detect the high risk of cement leaks among advanced cancer patients with metastatic spinal disease treated with percutaneous vertebroplasty.

Methods

This study retrospectively analyzed 309 patients with metastatic spinal disease treated with percutaneous vertebroplasty. Patients were randomly divided into a training group and a validation group. In the training group, 13 potential characteristics were analyzed for their abilities to predict cement leaks. Discal cement leakage and paravertebral cement leakage were excluded from the analysis. Those characteristics identified as having significant predictive value were used to develop a predictive algorithm. Internal validation of the algorithm was performed based on discrimination and calibration qualities.

Results

Overall, cement leaks occurred in 61.17% (189/309) patients. Among the 13 characteristics analyzed, younger age (P = 0.03), extravertebral bone metastases (P = 0.02), increased number of treated vertebrae levels (P < 0.01), and cortical osteolytic destruction in the posterior wall (P = 0.01) were included in the algorithm. This algorithm generates a score between 0 and 16 points, with higher scores indicating a higher risk of cement leakage. The area under the receiver operating characteristic curve (AUROC) value for the algorithm was 0.75 in the training group and 0.69 in the validation group. The mean correct classification rates for the training and validation groups were 73.5% and 64.9%, respectively, and the corresponding P-values of the goodness-of-fit test were 0.70 and 0.50.

Conclusions

Cement leaks are common in patients with metastatic spinal disease treated with percutaneous vertebroplasty. The present study proposed and internally validated an algorithm that can be used to screen patients at high risk of cement leakage.

Standardized uptake values of 99mTc-MDP in normal vertebrae assessed using quantitative SPECT/CT for differentiation diagnosis of benign and malignant bone lesions

BACKGROUND

Quantitative bone SPECT/CT is useful for disease follow up and inter-patient comparison. For bone metastatic malignant lesions, spine is the most commonly invaded site. However, Quantitative studies with large sample size investigating all the segments of normal cervical, thoracic and lumbar vertebrae are seldom reported. This study was to evaluate the quantitative tomography of normal vertebrae using ^99mTc-MDP with SPECT/CT to investigate the feasibility of standardized uptake value (SUV) for differential diagnosis of benign and malignant bone lesions.

METHODS

A retrospective study was carried out involving 221 patients (116 males and 105 females) who underwent SPECT/CT scan using ^99mTc-MDP. The maximum SUV (SUV_max), mean SUV (SUV_mean) and CT values (Hounsfield Unit, HU) of 2416 normal vertebrae bodies, 157 benign bone lesions and 118 malignant bone metastasis foci were obtained. The correlations between SUV_max of normal vertebrae and CT values of normal vertebrae, age, height, weight, BMI of patients were analyzed. Statistical analysis was performed with data of normal, benign and malignant groups corresponding to same sites and gender.

RESULTS

The SUV_max and SUV_mean of normal vertebrae in males were markedly higher than those in females (P < 0.0009). The SUV_max of each normal vertebral segment showed a strong negative correlation with CT values in both males and females (r = - 0.89 and - 0.92, respectively; P < 0.0009). The SUV_max of normal vertebrae also showed significant correlation with weight, height, and BMI in males (r = 0.4, P < 0.0009; r = 0.28, P = 0.005; r = 0.22, P = 0.026), and significant correlation with weight and BMI in females (r = 0.32, P = 0.009; r = 0.23, P = 0.031). The SUV_max of normal group, benign bone lesion group and malignant bone metastasis foci group showed statistical differences in both males and females.

CONCLUSION

Our study evaluated SUV_max and SUV_mean of normal vertebrae, benign bone lesion and malignant bone metastasis foci with a large sample population. Preliminary results proved the potential value of SUV_max in differentiation benign and malignant bone lesions. The results may provide a quantitative reference for clinical diagnosis and the evaluation of therapeutic response in vertebral lesions.

Cement Plug Fragmentation Following Percutaneous Cementoplasty of the Bony Pelvis: Is it a Frequent Finding in Clinical Practice?

PURPOSE

To report the rate of fragmentation of the cement plug following percutaneous cementoplasty with polymethylmethacrylate (PMMA) in the bony pelvis (i.e., pelvic bones or sacrum).

MATERIALS AND METHODS

Post-interventional and follow-up CT scans of 56 patients (36 men; mean age of 68.4 ± 15.4) with a total of 98 percutaneous cementoplasty procedures were analyzed. Indications for treatment included painful malignant tumors (42.9%; 42/98) and insufficiency fractures (57,1%; 56/98). Fragmentation of PMMA was recorded for each cement plug.

RESULTS

Mean interval between the procedure and the last available CT scan was 29.3 ± 18.8 months. There was no significant difference between the length of follow-up of malignant lesions (27.6 ± 15.1 months) and insufficiency fractures (29 ± 20.5 months) (p = 0.69). Fragmentation was diagnosed following 2/98 (2%) procedures, both in the malignant lesions group. The time intervals between the procedure and the first visualization of cement fragmentation were 6 for the first and 24 months for the second patient.

CONCLUSION

Fragmentation of the PMMA plug following percutaneous cementoplasty in the bony pelvis is a rare finding at midterm follow-up. It was only observed in cementoplasty performed in malignant lesions and seems to be more a consequence of local mechanical stresses than as a result of porosity.

The First Algorithm Calculating Cement Injection Volumes in Patients with Spine Metastases Treated with Percutaneous Vertebroplasty

PURPOSE

This study aims to develop an algorithm to predict cement injection volumes in patients with spine metastases treated with percutaneous vertebroplasty (PVP). Risk factors were also analyzed for intra-spinal canal cement leakages.

PATIENTS AND METHODS

A retrospective analysis of 584 vertebrae in 251 patients. Patients and vertebrae were divided into three groups based on grades of tumor invasion to the spinal cord. Patients with the complete posterior wall of vertebrae were classified into group A, patients without the complete posterior wall of vertebrae but with normal Dural sac were classified into group B, and patients with deformation of the Dural sac but without neurological symptom were classified into group C. We systematically reviewed demographic data, clinical parameters, radiology features, and cement leakages among the three groups. The multiple linear regressions were used to screen potential risk factors and develop the algorithm to predict injected cement volumes in vertebrae. Significant factors were included in the algorithm. Potential risk factors for intra-spinal canal cement leakage were analyzed using the multiple logistic regressions.

RESULTS

In the study, 17.1% (100/584) of vertebrae occurred cement leakages. Vertebrae in group C (28.6%, 8/28) had the highest cement leakage rate than patients in group A (14.4%, 61/424) and B (23.5%, 31/132) (P=0.014). Vertebrae in group C (14.3%, 4/28) were also more prone to intra-spinal canal leakages (P=0.003). The multiple logistic analysis showed that the Bilsky scale was significantly associated with intra-spinal canal cement leakages (P<0.001). The multiple linear regression analysis showed that intercept (P<0.001), treated vertebrae level (P<0.001), cortical osteolytic destruction in posterior wall (P<0.001), and Bilsky scale (P=0.014) were significant and those variables were included in the algorithm. The algorithm was Y=3.1627－0.8677×treated vertebrae level－0.6182×cortical osteolytic destruction in the posterior wall－0.2819×Bilsky scale.

CONCLUSION

An algorithm is proposed and can be used to calculate cement injection volumes in spine metastases treated with PVP. This algorithm can facilitate surgical planning and guide cement injections. Bilsky scale is an independent risk factor for intra-spinal canal cement leakages. We do not recommend PVP treated in patients with a Bilsky scale of 2 and 3 mainly due to a high rate of intra-spinal canal cement leakages.