Classifications in Brief: The Spinal Instability Neoplastic Score

Treatment Strategies for Intermediate Spinal Instability Neoplastic Score Patients: A Systematic Review

BACKGROUND

The Spinal Instability Neoplastic Score (SINS) is used in determining instability in patients with spinal metastases. Intermediate scores of 7 to 12 suggest possible instability, but there are no clear guidelines to address patients with these scores.

METHODS

We searched in PubMed, EMBASE, and Cochrane databases for studies that included patient demographics, tumor histology, surgical or radiotherapy management, and outcomes of patients with intermediate SINS. We reported mean differences and odds ratios (ORs) to assess differences between patients managed surgically versus with radiotherapy alone.

RESULTS

Thirteen articles, totaling 1822 patients with intermediate SINS were analyzed. In 5 studies (38.4%), the management decision was based on a tumor board review. There was no significant difference between surgical management versus radiotherapy (P = 0.24). When dichotomized into SINS 7-9 and 10-12, the OR for surgical management in the 10-12 group compared to the 7-9 group was 6.88 (95% confidence interval [CI] 2.31-20.5, P = 0.0005). More renal cell carcinomas were managed surgically instead of with radiotherapy alone than other tumor types (OR = 1.87, 95% CI = 1.14-3.05, P = 0.01). There was no statistical difference in overall complications between the 2 treatment groups (OR = 1.12, 95% CI = 0.49-2.54, P = 0.79). Vertebral fracture rates after any radiotherapy type ranged between 20% and 66%. The need for a surgical procedure, including stabilization, vertebroplasty, or kyphoplasty after radiotherapy ranged from 5% to 34.2%.

CONCLUSIONS

Complication rates after surgery versus radiotherapy in the intermediate SINS category are similar, but the complication types differ. Patients in the 10-12 SINS subgroup, due to larger lytic area and higher probability of vertebral body fracture, could benefit from stabilization before radiotherapy.

AI-Assisted Detection and Localization of Spinal Metastatic Lesions

OBJECTIVES

The integration of machine learning and radiomics in medical imaging has significantly advanced diagnostic and prognostic capabilities in healthcare. This study focuses on developing and validating an artificial intelligence (AI) model using U-Net architectures for the accurate detection and segmentation of spinal metastases from computed tomography (CT) images, addressing both osteolytic and osteoblastic lesions.

METHODS

Our methodology employs multiple variations of the U-Net architecture and utilizes two distinct datasets: one consisting of 115 polytrauma patients for vertebra segmentation and another comprising 38 patients with documented spinal metastases for lesion detection.

RESULTS

The model demonstrated strong performance in vertebra segmentation, achieving Dice Similarity Coefficient (DSC) values between 0.87 and 0.96. For metastasis segmentation, the model achieved a DSC of 0.71 and an F-beta score of 0.68 for lytic lesions but struggled with sclerotic lesions, obtaining a DSC of 0.61 and an F-beta score of 0.57, reflecting challenges in detecting dense, subtle bone alterations. Despite these limitations, the model successfully identified isolated metastatic lesions beyond the spine, such as in the sternum, indicating potential for broader skeletal metastasis detection.

CONCLUSIONS

The study concludes that AI-based models can augment radiologists' capabilities by providing reliable second-opinion tools, though further refinements and diverse training data are needed for optimal performance, particularly for sclerotic lesion segmentation. The annotated CT dataset produced and shared in this research serves as a valuable resource for future advancements.

Biomechanical analysis of stabilization for thoracolumbar anterior spinal failure caused by osteolytic lesions, a finite element comparison of direct lateral corpectomy and posterior long segment instrumentation

BACKGROUND CONTEXT

Osteolytic lesions caused by infection or metastatic disease of the spine can induce instability. Different surgical strategies are available to restore stability in this scenario, however little is known how various reconstruction techniques affect spinal biomechanics.

PURPOSE

To analyze and quantify the biomechanical effects of three different surgical reconstruction techniques in the treatment of a T12 osteolytic model.

STUDY DESIGN/SETTING

Finite element analysis of the thoracic spine with a T12 osteolytic lesion.

METHODS

Using CT scans from a 20-year-old man without structural deformity, simulation of an osteolytic lesion with a 50% defect at the posterior aspect of T12 vertebral body was created by a 490 N vertical force to T9. Next, three common instrumentation techniques treating the osteolytic lesion were modeled and biomechanically tested. These included: Model A, corpectomy with short segment fixation (T11-L1) and two long-segment instrumentations; Model B long segment fixation with triple rod construct; Model C long segment fixation with dual rod construct. A load of 480N was then applied on the spine models in vertically downward direction on T9. Von Mises stresses were measured (MPa) in the discs, vertebrae, and implants.

RESULTS

Model A demonstrated the lowest stress on construct material, adjacent vertebral bodies, and discs but increased stress on the instrumented vertebrae. Model B was more rigid and demonstrated lower construct stress compared to Model C. However, Model C had the lowest vertebral body stress in flexion, extension, and lateral bending in the most upper instrumented vertebral body, but the highest screw pull-out stress when compared to Model A and Model B.

CONCLUSIONS

This osteolytic T12 model provides unique biomechanical data that can help to tailor surgical strategies in select scenarios. While optimal outcomes are best achieved with a construct tailored to a specific patient's need for stabilization, our findings can be generalized for instances of cancerous lesions, low bone density, and infectious causes.

CLINICAL RELEVANCE

The results of this study can help with the choice of appropriate surgical reconstruction technique based on patient-specific characteristics.

Tumor markers in non-small cell lung cancer spine metastasis: an assessment of prognosis and overall survival

PURPOSE

The identification of gene mutations in the modern medical workup of metastatic spine tumors has become more common but has not been highly utilized in surgical planning. Potential utility of these genetic markers as surrogates for cancer behavior in current prognosis scoring systems and overall survival (OS) remains underexplored in existing literature. This study seeks to investigate the association of frequently identified tumor markers, EGFR, ALK, and PD-L1, in metastatic non-small cell lung cancer (NSCLC) to the spine with Tokuhashi prognosis scoring and OS.

METHODS

Patients with NSCLC metastasis to spine were identified through chart review. EGFR, ALK, and PD-L1 wild type vs. mutant type were identified from targeted chemotherapy genetic testing. Multiple linear regression was performed to assess gene profile contributions to Tokuhashi score. Cox Proportional Hazards models were generated for each tumor marker to assess the relationship between each marker and OS.

RESULTS

A total of 119 patients with NSCLC spine metastasis were identified. We employed a multiple linear regression analysis to investigate the influence of EGFR, ALK, and PD-L1 genotypes on the Tokuhashi score, revealing statistically significant relationships overall (p = 0.002). Individual genotype contributions include EGFR as a non-significant contributor (p = 0.269) and ALK and PD-L1 as significant contributors (p = 0.037 and p = 0.001 respectively). Overall survival was not significantly associated with tumor marker profiles through Kaplan-Meier analysis (p = 0.46) or by multivariable analysis (p = 0.108).

CONCLUSION

ALK and PD-L1 were significantly associated with Tokuhashi score while EGFR was not. Tumor markers alone were not predictive of OS. These findings indicate that genetic markers found in NSCLC metastases to the spine may demonstrate prognostic value. Therefore, employing standard tumor markers could enhance the identification of appropriate surgical candidates, although they demonstrate limited effectiveness in predicting overall survival.

The Spinal Instability Neoplastic Score correlates with epidural spinal cord compression -a retrospective cohort of 256 surgically treated patients with spinal metastases

BACKGROUND

Bone metastases can compromise the integrity of the spinal canal and cause epidural spinal cord compression (ESCC). The Spinal Instability Neoplastic Score (SINS) was developed in order to evaluate spinal instability due to a neoplastic process. The SINS has reached wide acceptance among clinicans but its prognostic value is still controversial. The aim was to investigate the correlation between the SINS and ESCC and the association between SINS and ambulation before and survival after surgery.

METHODS

Correlations were assessed between SINS and grades of ESCC in patients who underwent spine surgery for spinal metastases. CT and MRI were used to calculate SINS and the grades of ESCC respectively. Correlations were analyzed with the Spearman's correlation test. Postoperative survival was estimated with Kaplan-Meier analysis and survival curves were compared with the log-rank test. The Cox proportional hazard model was used to assess the effect of prognostic variables including age, ambulation before surgery, SINS, and the Karnofsky Performance Status (KPS) as covariates.

RESULTS

The study included 256 patients (196 men and 60 women) with a median age of 70 (24-88) years. The mean SINS was 10. One hundred fifty-two patients (59%) had lost ambulation before surgery. One hundred and one patients had grades 0-2 and 155 patients had grade 3 according to the ESCC-scale. SINS correlated with the grades of ESCC (p = 0.001). The SINS score was not associated with ambulation before surgery (p = 0.63). The median postoperative survival was 10 months, and there was no difference in postoperative survival between the SINS categories (p = 0.25). The ability to walk before surgery and a high KPS were associated with longer postoperative survival.

CONCLUSION

SINS correlated with grades of ESCC, which implies that higher SINS may be considered as an indicator of risk for developing ESCC. The SINS was not associated with ambulation before or survival after surgery.

Short-term assessment of functional outcomes and quality of life after thoracic and lumbar spinal metastasis surgery

Background

Because of improvements in initial tumor identification and treatment, as well as longer life expectancies, more people are receiving diagnoses for spinal metastases.

Objective

The aim of this study was to assess early functional outcomes and quality of life (QOL) after surgical management of patients with spinal metastases.

Patients and Methods

In this prospective cohort study, a total of 33 patients with thoracic and lumbar spine metastases who underwent surgical management between November 2021 and August 2023 were followed up for 1 year or until death. Oswestry Disability Index and the Eastern Cooperative Oncology Group Performance Status were used for the functional outcome; QOL was assessed using European Quality of Life 5-Dimensions (EuroQOL-5D). Scores were recorded preoperatively, 4 weeks postoperatively, and 6 and 12 months postoperatively.

Results

The mean age was 52.12 ± 13.4 years (range: 23-70 years), 22 (66.7%) were females, and 11 (33.3%) were males. Patients were divided into three groups according to the revised Katagiri score: 12 (36.4%) patients were at low risk (0-3), 18 (54.5%) patients were at intermediate risk (4-6), and 3 (9.1%) patients were at high risk (7-10). The mean survival was 5.44 ± 3.46 months (range 1-13), and there was no perioperative death (within 1 month postoperative). Sixteen (48.5%) patients survived for more than 1 year and 17 (51.5%) patients died from different causes related to the natural history of tumor metastasis.

Conclusion

Following surgical treatment of the spinal metastases, improvements in QoL and functional results were seen in the short-term. For patients with a projected life expectancy of longer than 3 months, surgery is a good alternative.

Combination radiofrequency ablation and vertebral cement augmentation for spinal metastatic tumors: A systematic review and meta-analysis of safety and treatment outcomes

Background

The treatment of spine metastases continues to pose a significant clinical challenge, requiring the integration of multiple therapeutic modalities to address the multifactorial aspects of this disease process. Radiofrequency ablation (RFA) and vertebral cement augmentation (VCA) are 2 less invasive modalities compared to open surgery that have emerged as promising strategies, offering the potential for both pain relief and preservation of vertebral stability. The utility of these approaches, however, remains uncertain and subject to ongoing investigation.This systematic review and meta-analysis evaluates the available evidence and synthesize the results of studies that have investigated the combination of RFA and VCA for the treatment of spinal metastases, with the goal of providing a comprehensive and up-to-date assessment of the efficacy and safety of this therapeutic approach.

Methods

A literature search was conducted using the electronic databases PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), and Scopus from their inception to May 4th, 2022 in accordance with PRISMA guidelines. Studies were included if they met the following criteria: 1) spine metastases treated with RFA in combination with VCA, 2) available data on at least one outcome (i.e., pain palliation, complications, local tumor control), 3) prospective or retrospective studies with at least 10 patients, and 4) English language. Meta-analyses were conducted in R (R Foundation for Statistical Computing; Vienna, Austria), using the meta package.

Results

In the 25 included studies, a total of 947 patients (females=53.9%) underwent RFA + VCA for spinal metastatic tumors. Out of 1,163 metastatic lesions, the majority were located in the lumbar region (585/1,163 [50.3%]) followed by thoracic (519/1,163 [44.6%]), sacrum (39/1,163 [3.4%]), and cervical (2/1,163 [0.2%]). 48/72 [66.7%] metastatic lesions expanded into the posterior elements. Preoperative pathologic vertebral fractures were identified in 115/176 [65.3%] patients. Between pre-procedure pain scores and postprocedure pain scores, average follow-up (FU) was 4.41±2.87 months. Pain scores improved significantly at a short-term FU (1-6 months), with a pooled mean difference (MD) from baseline of 4.82 (95% CI, 4.48-5.16). The overall local tumor progression (LTP) rate at short-term FU (1-6 months) was 5% (95% CI, 1%-8%), at mid-term FU (6-12 months) was 22% (95% CI, 0%-48%), and at long-term FU (>12 months) was 5% (95% CI, 0%-11%). The pooled incidence of total complications was 1% (95% CI, 0%-1%), the most frequent of which were transient radicular pain and asymptomatic cement extravasation.

Conclusions

The findings of this meta-analysis reveal that the implementation of RFA in conjunction with VCA for the treatment of spinal metastatic tumors resulted in a significant short-term reduction of pain, with minimal total complications. The LTP rate was additionally low. The clinical efficacy and safety of this technique are established, although further exploration of the long-term outcomes of RFA+VCA is warranted.

Resection of Thoracic Plasmacytoma and Corpectomy Through the Anterolateral Thoracic Approach: A Case Report

This case report details the case of a 57-year-old male who initially manifested low back pain radiating from the lumbar region to the left leg. Progressive symptoms included paresthesia on the plantar surfaces of both feet and gait instability attributed to weakness in the pelvic limbs. Computed tomography imaging revealed osteolytic lesions in the T9, T10, and T11 vertebral bodies, resulting in compression of the spinal cord. Subsequent contrast-enhanced magnetic resonance imaging validated these findings, confirming the presence of an extradural tumor. In accordance with the Spinal Instability Neoplastic Score (SINS), the case was categorized as indicative of potential spinal instability. Consequently, a surgical intervention was performed to excise the lesion. Thus, the role of SINS played a pivotal role in guiding the decision-making process for the chosen treatment modality.

Determining patients with spinal metastases suitable for surgical intervention: A cost-effective analysis

BACKGROUND

Both nonoperative and operative treatments for spinal metastasis are expensive interventions. Patients' expected 3-month survival is believed to be a key factor to determine the most suitable treatment. However, to the best of our knowledge, no previous study lends support to the hypothesis. We sought to determine the cost-effectiveness of operative and nonoperative interventions, stratified by patients' predicted probability of 3-month survival.

METHODS

A Markov model with four defined health states was used to estimate the quality-adjusted life years (QALYs) and costs for operative intervention with postoperative radiotherapy and radiotherapy alone (palliative low-dose external beam radiotherapy) of spine metastases. Transition probabilities for the model, including the risks of mortality and functional deterioration, were obtained from secondary and our institutional data. Willingness to pay thresholds were prespecified at $100,000 and $150,000. The analyses were censored after 5-year simulation from a health system perspective and discounted outcomes at 3% per year. Sensitivity analyses were conducted to test the robustness of the study design.

RESULTS

The incremental cost-effectiveness ratios were $140,907 per QALY for patients with a 3-month survival probability >50%, $3,178,510 per QALY for patients with a 3-month survival probability <50%, and $168,385 per QALY for patients with independent ambulatory and 3-month survival probability >50%.

CONCLUSIONS

This study emphasizes the need to choose patients carefully and estimate preoperative survival for those with spinal metastases. In addition to reaffirming previous research regarding the influence of ambulatory status on cost-effectiveness, our study goes a step further by highlighting that operative intervention with postoperative radiotherapy could be more cost-effective than radiotherapy alone for patients with a better survival outlook. Accurate survival prediction tools and larger future studies could offer more detailed insights for clinical decisions.

Percutaneous pedicle screw fixation combined with percutaneous vertebroplasty for the treatment of thoracic and lumbar metastatic tumors

Background and Aim

With the greatly prolonged survival of cancer patients, more and more patients develop bone metastasis, especially spinal metastasis. Therefore, it is very important to choose the best surgical plan for patients with spinal metastasis in different conditions. This paper aims to evaluate the clinical efficacy of percutaneous pedicle screw fixation (PPSF) combined with percutaneous vertebroplasty (PVP) for the treatment of thoracic and lumbar metastatic tumors.

Methods

Forty patients with thoracic and lumbar metastatic tumors were treated with PPSF combined with PVP and followed up for 6-33 months. The visual analog scale (VAS) and the Barthel Index of activities of daily living (BIADL) were used to evaluate the pain intensity and quality of life before surgery and at 7 days, 3 months, and 6 months after the treatment.

Results

In this study, a total of 40 patients were followed up for 6-33 months (the mean time was 14.87 months). The VAS scores of all patients were significantly decreased, while the BIADL scores were significantly increased. No patients suffered from complications such as infection, pedicle screw loosening, or polymethylmethacrylate leakage. Spine stability was observed in all surviving patients during the follow-up.

Conclusions

PPSF combined with PVP is a new and viable treatment for thoracolumbar metastases in patients with a poor systemic condition, patients who refuse to undergo a conventional open procedure such as en bloc corpectomy, and in patients with vertebral instability or pathological fracture without significant spinal compression.

Relevance for Patients

Patients with spinal metastases have a great risk of spinal instability and even spinal cord compression while enduring pain. Therefore, timely and appropriate surgical treatment is an effective means to stabilize the spine and avoid spinal cord compression. PPSF combined with PVP is an effective new surgical method for the treatment of multilevel spinal metastases.

Prescribing Exercise to Cancer Patients Suffering from Increased Bone Fracture Risk Due to Metastatic Bone Disease or Multiple Myeloma in Austria-An Inter- and Multidisciplinary Evaluation Measure

INTRODUCTION

In the current absence of specific functional fracture risk assessment technology, the planning of physical exercise interventions for cancer patients suffering from increased bone fracture risk remains a serious clinical challenge. Until a reliable, solely technical solution is available for the clinician, fracture risk assessment remains an inter- and multidisciplinary decision to be made by various medical experts. The aim of this short paper is depicting how this challenge should be approached in the clinical reality according to Austrian experts in cancer rehabilitation, presenting the best-practice model in Austria. Following referral from the specialist responsible for the primary cancer treatment (oncologist, surgeon, etc.), the physiatrist takes on the role of rehabilitation case manager for each individual patient. Fracture risk assessment is then undertaken by specialists in radiology, orthopedics, oncology, and radiation therapy, with the result that the affected bone regions are classified as being at highly/slightly/not increased fracture risk. Following internal clearance, exercise planning is undertaken by a specialist in exercise therapy together with the physiatrist based on the individual's fracture risk assessment. In the case in which the patient shows exercise limitations due to additional musculoskeletal impairments, adjuvant physical modalities such as physiotherapy should be prescribed to increase exercisability.

CONCLUSION

Exercise prescription for cancer patients suffering from increased fracture risk is an inter- and multidisciplinary team decision for each individual patient.

Imaging of metastatic epidural spinal cord compression

Metastatic epidural spinal cord compression develops in 5-10% of patients with cancer and is becoming more common as advancement in cancer treatment prolongs survival in patients with cancer (1-3). It represents an oncological emergency as metastatic epidural compression in adjacent neural structures, including the spinal cord and cauda equina, and exiting nerve roots may result in irreversible neurological deficits, pain, and spinal instability. Although management of metastatic epidural spinal cord compression remains palliative, early diagnosis and intervention may improve outcomes by preserving neurological function, stabilizing the vertebral column, and achieving localized tumor and pain control. Imaging serves an essential role in early diagnosis of metastatic epidural spinal cord compression, evaluation of the degree of spinal cord compression and extent of tumor burden, and preoperative planning. This review focuses on imaging features and techniques for diagnosing metastatic epidural spinal cord compression, differential diagnosis, and management guidelines.

Effectiveness of Rehabilitation for Cancer Patients with Bone Metastasis

Objectives:

Advances in cancer treatment have led to extended survival, and, as a result, the number of patients with bone metastases is increasing. Activities of daily living (ADL) decrease with bone metastasis and the need for rehabilitation is increasing. This study examined the effects of rehabilitation in patients with bone metastases.

Methods:

We retrospectively reviewed data of cancer patients with bone metastasis who received rehabilitation between 2016 and 2018. Efficacy of rehabilitation was evaluated in 92 patients as the change in the Functional Independence Measure (FIM) score divided by rehabilitation days (FIM change/day) and assessed by different metastatic sites.

Results:

Overall FIM scores significantly improved after rehabilitation. Moreover, FIM change/day improved in patients with pelvic metastases (n=44) more than in patients with other metastatic sites (n=48) (P=0.015). In FIM motor components, improvements in toilet, tub/shower, walk/wheelchair, and stairs were significantly greater in patients with pelvic metastasis than in those with other metastasis sites.

Conclusions:

Rehabilitation improved ADL status to a greater extent in patients with pelvic metastases than in those with other metastasis sites. Patients with pelvic metastases may fear fractures, limiting their ADL, but rehabilitation could eliminate this fear and improve FIM.

Minimally invasive surgery for spinal fractures due to multiple myeloma

Background:

Multiple myeloma (MM) presents with spinal lesions in 60% of cases. The combination of osteolytic lesions with multifactorial osteopenia raises specific surgical treatment challenges. Minimally invasive spine surgery (MISS) could be a potential option for MM spinal lesions treatment.

Objective:

The objective of this study is to evaluate MISS techniques to treat patients presenting with spine fractures due to MM

Methods:

Retrospective analysis of consecutive patients with histology-proven pathological fractures caused by MM treated with MISS between 2009 and 2018. We collected the data from the clinical records on epidemiology, topography of spine lesions, surgical techniques, blood loss, operation time, complications, mean in-hospital time, and clinical evolution.

Results:

Twenty-one patients were studied – 13 males and 8 females, with a mean age of 64 years (range 43–83). Mean preoperative spinal instability neoplastic score was 9.8 ± 6 (range 5–16). All cases had a thoracolumbar location – 15 patients underwent kyphoplasty (KP) or vertebroplasty (VP) and 6 were treated with other more complex procedures. All patients had a reduction of pain and/or analgesic load. Vertebral body height increased by a mean of 2.9 mm after VP/KP. Mean hospital stay was 1.3 days for KP/VP and 5.0 days for other MISS procedures. Three patients had complications.

Conclusions:

The heterogeneity of techniques used reflected the variety of spine involvement by MM. KP and VP led to shorter hospital stays and less complications, being adequate for lesions without major instability. More complex MISS techniques offer an effective treatment with short delay for starting MM adjuvant treatment.

Accuracy and precision of the spinal instability neoplastic score (SINS) for predicting vertebral compression fractures after radiotherapy in spinal metastases: a meta-analysis

Radiotherapy has played an important role in the treatment of spinal metastases. One of the major complications of radiotherapy is vertebral compression fracture (VCF). Although the spinal instability neoplastic score (SINS) was developed for evaluating spinal instability in patients with spinal metastases, it is also commonly used to predict VCF after radiotherapy in patients with spinal metastases. However, its accuracy for predicting radiotherapy-induced VCF and precision remain controversial. The aim of this study was to clarify the diagnostic value of the SINS to predict radiotherapy-induced VCF and to make recommendations for improving its diagnostic power. We searched core databases and identified 246 studies. Fourteen studies were analyzed, including 7 studies (with 1269 segments) for accuracy and 7 studies (with 280 patients) for precision. For accuracy, the area under the summary receiver operating characteristic curve was 0.776. When a SINS cut-off value of 7 was used, as was done in the included studies, the pooled sensitivity was 0.790 and the pooled specificity was 0.546. For precision, the summary estimate of interobserver agreement was the highest dividing 2 categories based on a cut-off value of 7, and the value was 0.788. The body collapse showed moderate relationship and precision with the VCF. The lytic tumor of bone lesion showed high accuracy and fair reliability, while location had excellent reliability, but low accuracy. The SINS system can be used to predict the occurrence of VCF after radiotherapy in spinal metastases with moderate accuracy and substantial reliability. Increasing the cut-off value and revising the domains may improve the diagnostic performance to predict the VCF of the SINS.

Is the Spinal Instability Neoplastic Score Accurate and Reliable in Predicting Vertebral Compression Fractures for Spinal Metastasis? A Systematic Review and Qualitative Analysis

Spinal metastases can present with varying degrees of mechanical instability. The Spinal Instability Neoplastic Score (SINS) was developed as a tool to assess spinal neoplastic-related instability while helping to guide referrals among oncology specialists. Some previous papers suggested that the SINS was accurate and reliable, while others disagreed with this opinion. We performed a systematic review regarding the SINS to evaluate its accuracy and precision in predicting vertebral compression fractures (VCFs). The 21 included studies investigated a total of 2118 patients. Thirteen studies dealt with the accuracy of SINS to predict post-radiotherapy VCFs, and eight dealt with the precision. Among 13 studies, 11 agreed that the SINS categories showed statistically significant accuracy in predicting VCF. Among eight studies, body collapse was effective for predicting VCFs in six studies, and alignment and bone lesion in two studies. Location has no statistical significance in predicting VCFs in any of the eight studies. The precision of SINS categories was substantial to excellent in six of eight studies. Among the six components of the SINS, the majority of the included studies reported that location showed near perfect agreement; body collapse, alignment, and posterolateral involvement showed moderate agreement; and bone lesion showed fair agreement. Bone lesion showed significant accuracy in predicting VCFs in half of eight studies, but displayed fair reliability in five of seven studies. Although location was indicated as having near perfect reliability, the component showed no accuracy for predicting VCFs in any of the studies and deleting or modifying the item needs to be considered. The SINS system may be accurate and reliable in predicting the occurrence of post-radiotherapy VCFs for spinal metastasis. Some components seem to be substantially weak and need to be revised.