Only Tumors Angiographically Identified as Hypervascular Exhibit Lower Intraoperative Blood Loss Upon Selective Preoperative Embolization of Spinal Metastases: Systematic Review and Meta-Analysis

Spinal tumor embolization with Onyx: A systematic review and meta-analysis

INTRODUCTION

Onyx embolization has emerged as a promising technique for spinal tumor embolization due to its high devascularization rate and low incidence of complications.

OBJECTIVE

Evaluate the safety and efficacy of Onyx embolization in spinal tumor procedures.

METHODS

Following the PRISMA guidelines, we conducted a systematic review and meta-analysis. To be included, the articles had to report specific outcomes of Onyx embolization for spinal tumors (complications, mortality, blood loss, tumor devascularization, or reduction in tumor blush).

RESULTS

We selected 11 out of 2941 articles, encompassing 127 patients. Among them, no major complications or persistent neurological deficits were reported, and no deaths occurred as a result of the embolization procedure. Of the 63 patients with available data, two complications were observed: one infarct leading to transient neurological deficit and one clinically silent vessel perforation related to the microcatheter. Thus, the complication rate was 1% (95% confidence interval (CI): 0% to 6%). Blood loss during surgery ranged from 100 to 1500 mL (four studies). Complete tumor blush reduction was achieved in 52% of the cases (95% CI: 16% to 88%) across 32 patients. Three studies reported a median percentage of tumor devascularization of 91% (86.1% to 97.5%).

CONCLUSION

Onyx embolization for spinal tumor procedures appears to be a safe technique, as evidenced by the absence of major complications or deaths. However, the determination of its efficacy remains challenging due to limited data availability and substantial heterogeneity across studies. These findings highlight the need for future research to address this knowledge gap and further validate our results.

Refinement of nBCA embolization technique in treatment of metastatic spinal tumors: Case series and technical report

BACKGROUND AND OBJECTIVES

Preoperative embolization of metastatic spinal tumors (MSTs) has proven advantageous in limiting intraoperative blood loss (IBL) during resection. N-butyl cyanoacrylate (nBCA) is a liquid embolic agent known for its rapid hemostatic effects. However, nBCA is associated with a higher risk of distal nontarget embolization. This study highlights the refinement of the embolization technique and assesses its efficacy in performing an initial distal segmental artery plug with concentrated nBCA followed by proximal diluted nBCA for MSTs.

METHODS

A retrospective review of patients with MST (2018-2023) was performed. Patients who underwent preoperative nBCA endovascular embolization prior to tumor resection and spinal instrumentation were included. Baseline standard spinal angiography was performed.

RESULTS

Sixteen patients (13 men, 3 women; 56.0 ± 12.4 years) met inclusion criteria. And 43.75% (7 of 16) had thoracic levels, 37.5% (6 of 16) lumbar, and 18.75% (3 of 16) sacral. The most common primary tumor was renal cell carcinoma (43.75%, 7 of 16). A total of 43 pedicles were embolized (median 3), resulting in complete/near complete obliteration of the tumor blush. Most pedicles (83.7%, 36 of 43) received a single dilute concentration of nBCA; however, 16.3% (7 of 43) received two separate concentrations of nBCA, a denser concentration distally into the segmental artery and a diluted concentration proximally into the tumor bed. Mean IBL was 1150 ± 1201 mL in 3 distal plug patients distal plug patients versus 1625 ± 681 mL in 12 other patients. There were no complications related to embolization.

CONCLUSION

Performing a distal, concentrated nBCA plug during preoperative nBCA embolization of MSTs may increase tumor penetration and reduce IBL.

Does Patient Blood Management Affect Outcomes in Metastatic Spine Tumour Surgery? A Review of Current Concepts

STUDY DESIGN

Narrative review.

OBJECTIVE

The spine is the most common site of metastases, associated with decreased quality of life. Increase in metastatic spine tumour surgery (MSTS) has caused us to focus on the management of blood, as blood loss is a significant morbidity in these patients. However, blood transfusion is also not without its own risks, and hence this led to blood conservation strategies and implementation of a concept of patient blood management (PBM) in clinical practise focusing on these patients.

METHODS

A narrative review was conducted and all studies that were related to blood management in metastatic spine disease as well as PBM surrounding this condition were included.

RESULTS

A total of 64 studies were included in this review. We discussed a new concept of patient blood management in patients undergoing MSTS, with stratification to pre-operative and intra-operative factors, as well as anaesthesia and surgical considerations. The studies show that PBM and reduction in blood transfusion allows for reduced readmission rates, lower risks associated with blood transfusion, and lower morbidity for patients undergoing MSTS.

CONCLUSION

Through this review, we highlight various pre-operative and intra-operative methods in the surgical and anaesthesia domains that can help with PBM. It is an important concept with the significant amount of blood loss expected from MSTS.

LEVEL OF EVIDENCE

Not applicable.

Efficacy of Subtraction Computed Tomography Arteriography During Preoperative Embolization in Spinal Tumors

Background

This study aimed to evaluate the efficacy of subtraction computed tomography arteriography (s-CTA) during preoperative embolization in spinal tumors.

Methods

The study analyzed 17 vertebrae in 13 patients who underwent preoperative embolization before spinal fixation surgery for malignant spinal tumors to decrease blood loss at our hospital from 2019 to 2021. Their ages ranged from 56 to 88 years (average, 73.5 years). Metastatic bone tumors were most common, including five cases originating as lung carcinomas and three as renal cancers. After digital subtraction angiography of selected tumor-feeding arteries and non-subtraction CTA (ns-CTA) were performed, s-CTA was conducted using data obtained from both procedures. A clarity score of the boundary between the normal bone and tumor was derived for each patient, which was then classified into four grades (good, 3 points; fair, 2 points; faint, 1 point; poor, 0 points) by two experienced radiologists, followed by a comparison between the s-CTA and ns-CTA groups using the Wilcoxon signed-rank test.

Results

Clarity scores were significantly higher in the s-CTA group than in the ns-CTA group (P < 0.001). The agreement of Cohen's coefficients between the two radiologists was κ = 0.724 in s-CTA scoring and κ = 0.622 in ns-CTA scoring, which were moderately matched. Seven arteries were not embolized due to insufficient tumor contrast enhancement and their poor relation to the surgical invasion zone. No complications were observed during or after embolization.

Conclusion

S-CTA successfully distinguished between tumor and normal bone and may help avoid unnecessary embolization.

Quantile regression-based prediction of intraoperative blood loss in patients with spinal metastases: model development and validation

PURPOSE

To develop and evaluate a quantile regression-based blood loss prediction model for open surgery of spinal metastases.

METHODS

This was a multicenter retrospective cohort study. Over a 11-year period, patients underwent open surgery for spinal metastases at 6 different institutions were reviewed. The outcome measure is intraoperative blood loss (in mL). The effects of baseline, histology of primary tumor and surgical procedure on blood loss were evaluated by univariate and multivariate analysis to determine the predictors. Multivariate ordinary least squares (OLS) regression and 0.75 quantile regression were used to establish two prediction models. The performance of the two models was evaluated in the training set and the test set, respectively.

RESULTS

528 patients were included in this study. Mean age was 57.6 ± 11.2 years, with a range of 20-86 years. Mean blood loss was 1280.1 ± 1181.6 mL, with a range of 10 ~ 10,000 mL. Body mass index (BMI), tumor vascularization, surgical site, surgical extent, total en bloc spondylectomy and microwave ablation use were significant predictors of intraoperative blood loss. Hypervascular tumor, higher BMI, and broader surgical extent were related with massive blood loss. Microwave ablation is more beneficial in surgery with substantial blood loss. Compared to the OLS regression model, the 0.75 quantile regression model may decrease blood loss underestimate.

CONCLUSION

In this study, we developed and evaluated a prediction model for blood loss in open surgery for spinal metastases based on 0.75 quantile regression, which may minimize blood loss underestimate.

Efficacy of preoperative embolization for metastatic spinal tumor surgery using angiographic vascularity assessment

OBJECTIVES

Preoperative embolization (PE) for metastatic spinal tumors is a method of minimizing intraoperative blood loss during aggressive surgery. This study specified angiographic standards and investigated the influence of these and other factors on blood loss in patients with spinal metastases and various pathologies.

METHODS

The cohort comprised 126 consecutive patients receiving PE from 2015 to 2021. Their clinical, surgical, and angiographic characteristics were reviewed. Standard angiographic grading was used for vascularity assessment. Degree of embolization was divided into complete (≥ 90%), near complete (67 to < 90%), and partial (< 67%). Logistic regression analysis was used to investigate factors predictive of massive blood loss (> 2500 mL). A proportional odds model was used to assess factors predictive of the degree of embolization.

RESULTS

Mean intraoperative blood loss was 1676 mL. Among the patients, 62 had hypervascular tumors and 64 had nonhypervascular tumors, according to the angiographic classification. Intraoperative blood loss differed significantly with embolization degree, both overall (p < 0.001) and in the hypervascular and nonhypervascular groups (p = 0.01 and 0.03). Angiographic hypervascularity, spinal metastasis invasiveness index, and embolization degree were significant predictors of massive blood loss in univariate analysis, but only embolization degree was significant in multivariate analysis. Only the presence of the radiculomedullary artery at the target level was significant in both the univariate and multivariate analyses for embolization degree.

CONCLUSIONS

In addition to pathological classification, angiographic vascularity assessment is valuable. Although complete embolization is a reasonable goal, it is challenging to achieve in cases of visible radiculomedullary artery.

KEY POINTS

• Angiography has a supplementary role in vascularity assessment for spinal metastatic surgery. • Better embolization degree is associated with less intraoperative blood loss in both angiographic hypervascular and nonhypervascular groups. • Presence of radiculomedullary artery in the target level causes worse embolization outcome.

Prognostic Analysis of Spinal Metastasis Secondary to Lung Cancer after Surgeries: A Unicentric, Large-Cohort, Retrospective Study

PURPOSE

Spinal metastases of lung cancer (SMLC) usually have high degree of malignancy and require surgical treatment. However, there are several controversies about the efficacy of surgery. This study aimed to investigate factors predicting prognosis of SMLC after surgery-based comprehensive treatment.

METHODS

A cohort of 112 cases of SMLC who underwent surgical treatment between 2009 and 2020 were retrospectively reviewed and analyzed. The surgical strategies included total en-bloc spondylectomy, debulking surgery, palliative decompression, and vertebral augmentation procedures. The patients were regularly followed-up. Survival analysis was performed, as well as analysis of the patients' neurological recovery, pain relief, and improvement of Karnosky performance score (KPS). Cox regression was used to analyze influencing factors of survival time, and Kaplan-Meier method was performed in survival analysis.

RESULTS

The cohort included 63 males and 49 females, with an average age of 60.6 ± 10.6 years. Median survival time was 16 months. A total of 86.7% of paralysis patients' neurological function recovered and 83.9% of patients with low KPS score (10-40) improved. Surgical method was significantly correlated with improvement of neurological function (p < 0.001) and KPS (p < 0.001). The mean bleeding volume was 502 ml and operative time was 170 min. The survival rates at 3, 6, 12, 24, and 36 months were 92.0%, 80.4%, 63.4%, 63.4%, and 22.6%, respectively. Postoperative Frankel grade (p < 0.001), postoperative KPS score (p = 0.001), and application of molecular targeted drugs (p < 0.001) were significantly correlated with survival time in univariate analysis, while application of molecular targeted drugs was an independent predictor for a longer survival by a multivariate analysis.

CONCLUSION

Surgery-based comprehensive treatment brought a fair outcome, with elongated survival time. Surgery can significantly improve patients' neurological function and physical performance status. Adjuvant targeted therapy is an independent positive factor for patients' survival.

Preoperative embolization of hypervascular spinal tumors: Two case reports

The performance of preoperative embolization on a spinal tumor can be a useful adjunctive procedure that minimizes blood loss and complications, particularly for both metastatic and non-metastatic hypervascular tumors. We discuss two cases of hypervascular spinal tumors that were successfully treated with preoperative embolization and surgery. The first patient was an 18-year-old man who presented with cervical and shoulder pain for two months without paralysis or weakness. Magnetic resonance imaging revealed a tumor located in the D2 posterior vertebral arch that extended into the spinal canal and compressed the spinal cord. The second patient was a 68-year-old man with back pain that radiated to the legs for ten days. Magnetic resonance imaging revealed a mass in the L4 vertebral body. Both patients received tumor embolization and surgery. After surgery, neither patient experienced any major complications. Histological examination revealed osteoblastoma in the first patient and plasmacytoma in the second patient.

The role of percutaneous transarterial embolization in the management of spinal bone tumors: a literature review

PURPOSE

Spinal bone tumors include a heterogeneous broad of primary or metastatic lesions that may present as incidental findings or manifest with painful symptoms and pathological fractures. Optimal management of spine bone lesions is often difficult and treatment algorithms are usually solidly based on surgery. We aimed to evaluate the contribution of trans-arterial embolization in this field, with particular attention to the procedure efficacy, technical difficulties and complications.

METHODS

We present a literature review on the role of trans-arterial embolization in the management of spinal bone tumors, both primary and metastatic, evaluating its contribution as preoperative treatment, palliative procedure and standalone curative strategy.

RESULTS

Trans-arterial embolization provides an important contribution to reducing surgery hemorrhagic risks, offering a better visualization of the operating field, and possibly increasing tumor susceptibility to chemotherapy or radiation therapy. Nonetheless, it plays an important part in pain palliation, with the unquestionable advantage of being easily repeatable in case of necessity. Its curative role as a standalone therapy is still subject of debate, and at the present time, satisfactory results have been recorded only in the treatment of aneurysmal bone cysts.

CONCLUSION

Percutaneous trans-arterial embolization has established as a highly useful minimally invasive procedure in the management of spinal bone lesions, particularly as adjuvant preoperative therapy and palliative treatment.