Surgical management of metastatic disease of the lumbar spine: experience with 139 patients

Nadir Hemoglobin Concentration After Spinal Tumor Surgery: Association With Risk of Composite Adverse Events

STUDY DESIGN

Retrospective case-control study.

OBJECTIVE

To explore the association of early postoperative nadir hemoglobin with risk of a composite outcome of anemia-related and other adverse events.

METHODS

We retrospectively analyzed data from spinal tumor patients who received intraoperative blood transfusion between September 1, 2013 and December 31, 2020. Uni- and multivariate logistic regression was used to explore relationships of clinicodemographic and surgical factors with risk of composite in-hospital adverse events, including death. Subgroup analysis explored the relationship between early postoperative nadir hemoglobin and composite adverse events.

RESULTS

Among the 345 patients, 331 (95.9%) experienced early postoperative anemia and 69 (20%) experienced postoperative composite adverse events. Multivariate logistic regression analysis showed that postoperative nadir Hb (OR = .818, 95% CI: .672-.995, P = .044), ASA ≥3 (OR = 2.007, 95% CI: 1.086-3.707, P = .026), intraoperative RBC infusion volume (OR = 1.133, 95% CI: 1.009-1.272, P = .035), abnormal hypertension (OR = 2.199, 95% CI: 1.085-4.457, P = .029) were correlated with composite adverse events. The lumbar spinal tumor was associated with composite adverse events with a decreased odds compared to thoracic spinal tumors (OR = .444, 95% CI: .226-.876, P = .019). Compared to patients with postoperative nadir hemoglobin ≥11.0 g/dL, those with nadir <9.0 g/dL were at significantly higher risk of postoperative composite adverse events (OR = 2.709, 95% CI: 1.087-6.754, P = .032).

CONCLUSION

Nadir hemoglobin <9.0 g/dL after spinal tumor surgery is associated with greater risk of postoperative composite adverse events in patients who receive intraoperative blood transfusion.

Treatment progress of spinal metastatic cancer: a powerful tool for improving the quality of life of the patients

Spinal metastasis is a common secondary malignant tumor of the bone, often resulting in spinal cord and nerve root compression, leading to obvious pain and related compression symptoms. This condition has a high incidence and mortality rate. The treatment approach for most patients with spinal metastasis is primarily palliative. Consultation with a multidisciplinary team is widely accepted as a comprehensive treatment approach for patients with spinal metastases. With advancements in research and technology, the evaluation and treatment of spinal metastatic cancer are continuously evolving. This study provides an overview of surgical treatment, minimally invasive treatment, and radiotherapy for spinal metastatic cancer and also analyzes the clinical effects, advantages, and current limitations associated with various treatment approaches.

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.

Spinal metastases of bronchopulmonary cancers: interest of balloon kyphoplasty in the control of mechanical rachialgia

Introduction

Spinal metastases are a classic complication of lung cancer. New palliative treatment modalities have emerged. Among them are minimally invasive approaches such as balloon kyphoplasty. With the aim of evaluating the efficiency of balloon kyphoplasty in the control of spinal pain during these lesions, we report a series of 24 patients.

Methods and materials

Over a period of 6 years, we retrospectively studied 24 files of patients suffering from vertebral compression of metastatic pulmonary origin and treated by balloon kyphoplasty from January 2009 to December 2014 in the neurosurgery department of the North Hospital of Marseille (France).

Results

The mean age was 66.2 years (39–80 years) with a sex ratio of 5. Dorsal location was predominantly 17 cases. Balloon kyphoplasty involved one level in 14 patients. The general condition (Karnofski) was bad in 16 patients. Survival prediction was less than 6 months in 22 patients. The indication was mainly pain with a mean visual analog scale of 7.7. The evolution was marked by the regression of the painful symptomatology in all patients with a mean visual analog scale of 2.2 postoperatively. Postoperative complications were noted in two cases (pulmonary embolism, compression of the left iliac vein).

Conclusion

Our short series shows the efficacy and low morbidity of balloon kyphoplasty in the control of spinal pain secondary to vertebral metastases of bronchopulmonary cancers.

Holistic Approach to the Diagnosis and Treatment of Patients with Tumor Metastases to the Spine

The treatment of neoplastic spine metastases requires multi-faceted assessment and an interdisciplinary approach to patients. The metastases do not show specific symptoms but are often the first confirmation of the presence of a primary tumor in a patient. The diagnostic process includes imaging and invasive procedures, e.g., biopsy. It is essential to qualify the patient for an appropriate treatment using dedicated scales. Decompression of the spinal cord is a critical issue to save or restore neurological function in a patient with spine metastases. Surgical treatment ought to meet three criteria: release spinal cord and nerve roots, restore the spine’s anatomical relations, and ensure the internal stabilization of the spine. A good result from surgical treatment enables the continuation of radiotherapy, chemotherapy, hormone therapy, and targeted molecular therapy. Stereotactic radiosurgery and stereotactic body radiotherapy are more effective ways of treating spine metastases than conventional external beam radiotherapy. They allow higher doses of radiation, concentrated precisely at the tumor site. Our review summarizes the established and emerging concepts in the treatment of spine metastases. A holistic approach to the patient enables the selection of the appropriate therapy.

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.

The performance of frailty in predictive modeling of short-term outcomes in the surgical management of metastatic tumors to the spine

BACKGROUND CONTEXT

The concept of frailty has become increasingly recognized, and while patients with cancer are at increased risk for frailty, its influence on perioperative outcomes in metastatic spine tumors is uncertain. Furthermore, the impact of frailty can be confounded by comorbidities or metastatic disease burden.

PURPOSE

The purpose of this study was to evaluate the influence of frailty and comorbidities on adverse outcomes in the surgical management of metastatic spine disease.

STUDY DESIGN/SETTING

Retrospective analysis of a nationwide database to include patients undergoing spinal fusion for metastatic spine disease.

PATIENT SAMPLE

A total of 1,974 frail patients who received spinal fusion with spinal metastasis, and 1,975 propensity score matched non-frail patients.

OUTCOME MEASURES

Outcomes analyzed included mortality, complications, length of stay (LOS), nonroutine discharges and costs.

METHODS

A validated binary frailty index (Johns Hopkins Adjusted Clinical Groups) was used to identify frail and non-frail groups, and propensity score-matched analysis (including demographics, comorbidities, surgical and tumor characteristics) was performed. Sub-group analysis of levels involved was performed for cervical, thoracic, lumbar and junctional spine. Multivariable-regression techniques were used to develop predictive models for outcomes using frailty and the Elixhauser Comorbidity Index (ECI).

RESULTS

7,772 patients underwent spinal fusion with spinal metastasis, of which 1,974 (25.4%) patients were identified as frail. Following propensity score matching for frail (n=1,974) and not-frail (n=1,975) groups, frailty demonstrated significantly greater medical complications (OR=1.58; 95% CI 1.33-1.86), surgical complications (OR=1.46; 95% CI 1.15-1.85), LOS (OR=2.65; 95% CI 2.09-3.37), nonroutine discharges (OR=1.79; 95% CI 1.46-2.20) and costs (OR=1.68; 95% CI 1.32-2.14). Differences in mortality were only observed in subgroup analysis and were greater in frail junctional and lumbar spine subgroups. Models using ECI alone (AUC=0.636-0.788) demonstrated greater predictive ability compared to those using frailty alone (AUC=0.633-0.752). However, frailty combined with ECI improved the prediction of increased LOS (AUC=0.811), cost (AUC=0.768), medical complications (AUC=0.723) and nonroutine discharges (AUC=0.718). Predictive modeling of frailty in subgroups demonstrated the greatest performance for mortality (AUC=0.750) in the lumbar spine, otherwise performed similarly for LOS, costs, complications, and discharge across subgroups.

CONCLUSIONS

A high prevalence of frailty existed in the current patient cohort. Frailty contributed to worse short-term adverse outcomes and could be more influential in the lumbar and junctional spine due to higher risk of deconditioning in the postoperative period. Predictions for short term outcomes can be improved by adding frailty to comorbidity indices, suggesting a more comprehensive preoperative risk stratification should include frailty.

Clinical utility of convolutional neural networks for treatment planning in radiotherapy for spinal metastases

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We presented a CNN workflow for segmentation and labeling of vertebrae on CT.

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This approach proved to be robust in a majority of cases with spinal metastases.

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The presented workflow can save time in a clinical radiotherapy setting.

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The approach also allows for more advanced quantitative image analysis of vertebrae.

Background and purpose

Spine delineation is essential for high quality radiotherapy treatment planning of spinal metastases. However, manual delineation is time-consuming and prone to interobserver variability. Automatic spine delineation, especially using deep learning, has shown promising results in healthy subjects. We aimed to evaluate the clinical utility of deep learning-based vertebral body delineations for radiotherapy planning purposes.

Materials and methods

A multi-scale convolutional neural network (CNN) was used for automatic segmentation and labeling. Two approaches were tested: the combined approach using one CNN for both segmentation and labeling, and the sequential approach using separate CNN’s for these tasks. Training and internal validation data included 580 vertebrae, external validation data included 202 vertebrae. For quantitative assessment, Dice similarity coefficient (DSC) and Hausdorff distance (HD) were used. Axial slices from external images were presented to radiation oncologists for subjective evaluation.

Results

Both approaches performed comparably during the internal validation (DSC: 96.7%, HD: 3.6 mm), but the sequential approach proved more robust during the external validation (DSC: 94.5% vs 94.4%, p < 0.001, HD: 4.5 vs 7.1 mm, p < 0.001). Subsequently, subjective evaluation of this sequential approach showed that experienced radiation oncologists could distinguish automatic from human-made contours in 63% of cases. They rated automatic contours clinically acceptable in 77% of cases, compared to 88% of human-made contours.

Conclusion

We present a feasible approach for automatic vertebral body delineation using two variants of a multi-scale CNN. This approach generates high quality automatic delineations, which can save time in a clinical radiotherapy workflow.

Inclusion of Frailty Improves Predictive Modeling for Postoperative Outcomes in Surgical Management of Primary and Secondary Lumbar Spine Tumors

BACKGROUND

Malignant spinal tumors are common, continually increasing in incidence as a function of improved survival times for patients with cancer. Using predictive analytics and propensity score matching, we evaluated the influence of frailty on postoperative complications compared with age in patients with malignant neoplasms of the lumbar spine.

METHODS

We used the Nationwide Readmissions Database from 2016 and 2017 to identify patients with malignant neoplasms of the lumbar spine who received a fusion procedure. Patient frailty was queried using the Johns Hopkins Adjusted Clinical Groups. Propensity score matching for age, sex, Charlson Comorbidity Index, surgical approach, and number of levels fused was implemented between frail and nonfrail patients, identifying 533 frail patients and 538 nonfrail patients. The area under the curve (AUC) of each ROC served as a proxy for model performance.

RESULTS

Frail patients reported significantly higher inpatient lengths of stay, costs, infection, posthemorrhagic anemia, and urinary tract infections (P < 0.05). In addition, frail patients were more often discharged to skilled nursing facilities and short-term hospitals compared with nonfrail patients (P < 0.0001). Regression models for mortality (AUC = 0.644), nonroutine discharge (AUC = 0.600), and acute infection (AUC = 0.666) were improved when using frailty as the primary predictor. These models were also improved using frailty when predicting 30-day readmission and 90-day hardware failure.

CONCLUSIONS

Frailty demonstrated a significant relationship with increased postoperative patient complications, length of stay, costs, and acute complications in patients receiving fusion following resection of a malignant neoplasm of the lumbar spine region. Frailty demonstrated better predictive validity of outcomes compared with patient age.

Resuscitative Endovascular Balloon Occlusion of the Aorta for Blood Control in Lumbar Spine Tumor Resection Surgery: A Technical Note

Objectives

To describe the technique of the aorta balloon occlusion, and evaluate the blood loss in lumbar spine tumor surgery assisted by aortic balloon occlusion, and to observe the balloon‐related complications.

Methods

Six patients with lumbar spine tumor underwent resuscitative endovascular balloon occlusion of the aorta prior to tumor resections in our institution between May 2018 to January 2021. Medical records including demographic, diagnosis, tumor location, surgical approach, intraoperative blood loss, surgical duration, and perioperative balloon‐related complication were evaluated retrospectively.

Results

This series included four males and two females, with a median age of 50 years (range 22 to 69). Of these, three primary tumors were plasmacytoma, giant cell tumor of bone, and osteosarcoma, while recurrence of undifferentiated pleomorphic sarcoma (UPS), recurrence of giant cell tumor of bone (GCT), and metastatic thyroid cancer were diagnosed in cases 1, 6, and 2, respectively. L₂ was involved in cases 1 and 5. L₃ was involved in case 6. L₄ was involved in case 2, 3, and 6. L₅ was involved in case 4. One‐stage total en bloc resection surgery (TES) was accomplished in all patients; of this series, signal anterior approach was conducted in case 1, signal posterior approach was utilized in cases 2, 3, and 6, while combined anterior and posterior approach was performed in cases 4 and 5. The median intraoperative blood loss was 1683 mL and ranged from 400 to 3200 mL with a median surgical duration of 442 min and a range from 210 to 810 min. During the perioperative period, no serious balloon‐related complications occurred.

Conclusions

Endovascular balloon occlusion of the aorta successfully controls intraoperative exsanguination, contributing to a more radical tumor resection and a low rate of tumor cell contamination in lumbar tumor surgery.

Sarcopenia as a Prognostic Factor for 90-Day and Overall Mortality in Patients Undergoing Spine Surgery for Metastatic Tumors: A Multicenter Retrospective Cohort Study

BACKGROUND

Novel methods in predicting survival in patients with spinal metastases may help guide clinical decision-making and stratify treatments regarding surgery vs palliative care.

OBJECTIVE

To evaluate whether the frailty/sarcopenia paradigm is predictive of survival and morbidity in patients undergoing surgery for spinal metastasis.

METHODS

A total of 271 patients from 4 tertiary care centers who had undergone surgery for spinal metastasis were identified. Frailty/sarcopenia was defined by psoas muscle size. Survival hazard ratios were calculated using multivariate analysis, with variables from demographic, functional, oncological, and surgical factors. Secondary outcomes included improvement of neurological function and postoperative morbidity.

RESULTS

Patients in the smallest psoas tertile had shorter overall survival compared to the middle and largest tertile. Psoas size (PS) predicted overall mortality more strongly than Tokuhashi score, Tomita score, and Karnofsky Performance Status (KPS). PS predicted 90-d mortality more strongly than Tokuhashi score, Tomita score, and KPS. Patients with a larger PS were more likely to have an improvement in deficit compared to the middle tertile. PS was not predictive of 30-d morbidity.

CONCLUSION

In patients undergoing surgery for spine metastases, PS as a surrogate for frailty/sarcopenia predicts 90-d and overall mortality, independent of demographic, functional, oncological, and surgical characteristics. The frailty/sarcopenia paradigm is a stronger predictor of survival at these time points than other standards. PS can be used in clinical decision-making to select which patients with metastatic spine tumors are appropriate surgical candidates.

A Novel Prediction Tool for Overall Survival of Patients Living with Spinal Metastatic Disease

OBJECTIVE

To identify the significant prognostic factors for overall survival in patients with spinal metastases and to establish an online widget for predicting survival with an interactive visual approach.

METHODS

Patients operated for spinal metastases between 2010 and 2018 were retrospectively enrolled and were randomly divided into training and validation samples with a ratio of 7:3. Patients' characteristics were analyzed with univariate and multivariate Cox analyses to identify independent prognostic factors basing on the training sample. A shiny web tool was developed by transforming the fitted multivariable Cox model into a visual interface. Time-dependent area under the curve plot and calibration curve were generated to assess the discrimination ability and consistency of the novel model, both for the training and validation samples.

RESULTS

A total of 265 consecutive patients were finally included, with 185 in the training sample and 80 in the validation sample. The primary tumor types, lesion site of metastasis, visceral metastasis, Frankel grade, operation category, number of surgical segments, and the preoperative percentage of lymphocyte were demonstrated to be significantly associated with overall survival. A novel shiny model (https://yang1209xg.shinyapps.io/predictspinalmetastasis/) that could provide predicted survival curve and median survival time was established, with favorable discrimination ability and consistency between predicted and actual survival both in internal and external data, according to time-dependent area under the curve plots and calibration curves.

CONCLUSIONS

A user-friendly shiny app with favorable discrimination ability and consistency was released online for predicting the survival of patients with spinal metastases. A continuous survival curve and the predicted median survival time are available to guide the treatment planning.

Comparison of 30-Day Outcomes in Patients with Cervical Spine Metastasis Undergoing Corpectomy Versus Posterior Cervical Laminectomy and Fusion: A 2006-2016 ACS-NSQIP Database Study

BACKGROUND

Patients with metastatic disease to the cervical spine have historically had poor outcomes, with an average survival of 15 months. Every effort should be made to avoid complications of surgical intervention for stabilization and decompression.

METHODS

We identified patients who had undergone anterior cervical corpectomy and fusion (ACCF) or posterior cervical laminectomy and fusion (PCLF) for metastatic disease of the cervical spine using the American College of Surgeons National Surgical Quality Improvement Program database from 2006 to 2016. Patients meeting the inclusion criteria were subsequently propensity matched 1:1. We compared the overall complications, intensive care unit level complications, mortality, and return to the operating room between the 2 groups.

RESULTS

After identifying the patients who met the inclusion criteria and propensity matching, a cohort of 240 patients was included, with 120 (50%) in the ACCF group and 120 (50%) in the PCLF group. The patients in the ACCF group were more likely to have experienced any complication (odds ratio, 2.1; 95% confidence interval, 1.1-4.1; P = 0.026) but not severe complications or a return to the operating room (P = 0.406 and P = 0.450, respectively).

CONCLUSION

In the present study, we found that anterior surgical approaches (ACCF) for metastatic cervical spine disease resulted in a significantly greater rate of overall complications (2.1 times more) compared with PCLF in the first 30 days. Although more studies are required to further elucidate this relationship, the general belief that the anterior approach is better tolerated by patients might not apply to patients with metastatic tumors.

Breast cancer spinal metastases: Prognostic factors affecting survival after surgery. A retrospective study

Breast cancer spinal metastases (BCSM) are common and require proper treatment that leads to an improvement of the quality of life and contributes to the quod vitam prognosis. Surgical treatment is often required for intractable pain, spinal cord compression or spinal instability. The aim of this retrospective study is to identify which prognostic factors could affect postoperative overall survival in patients affected by BCSM. We report a retrospective cohort study of patients with BCSM, surgically treated from September 2009 to May 2018. Demographic and clinical data were collected. Kaplan-Meier method was used to estimate overall survival, and the log-rank test was used to compare survival curves. A total of 77 patients were studied. The median age at the time of surgery was 54 years. The median follow-up was 49 months. The 3-year and 5-year overall survival rates were 61% (95%CI: 47.5-72.1) and 43.3% (95%CI: 28.8-57.1). Metastatic bone disease (p = 0.0196), preoperative neurological impairment (p = 0.0029), Karnofsky status <70 (p = 0.0241) reduce survival. With multivariate analysis, the effect of Karnofsky score loses statistical significance. The presence of concurrent bone metastases and a preoperative neurological deficit are independent prognostic factors. Therapeutic choices are based on a multidisciplinary assessment that takes into consideration several factors, including an accurate study of prognostic factors.

Development of Machine Learning Algorithms for Prediction of 30-Day Mortality After Surgery for Spinal Metastasis

BACKGROUND

Preoperative prognostication of short-term postoperative mortality in patients with spinal metastatic disease can improve shared decision making around end-of-life care.

OBJECTIVE

To (1) develop machine learning algorithms for prediction of short-term mortality and (2) deploy these models in an open access web application.

METHODS

The American College of Surgeons, National Surgical Quality Improvement Program was used to identify patients that underwent operative intervention for metastatic disease. Four machine learning algorithms were developed, and the algorithm with the best performance across discrimination, calibration, and overall performance was integrated into an open access web application.

RESULTS

The 30-d mortality for the 1790 patients undergoing surgery for spinal metastatic disease was 8.49%. Preoperative factors used for prognostication were albumin, functional status, white blood cell count, hematocrit, alkaline phosphatase, spinal location (cervical, thoracic, lumbosacral), and severity of comorbid systemic disease (American Society of Anesthesiologist Class). In this population, machine learning algorithms developed to predict 30-d mortality performed well on discrimination (c-statistic), calibration (assessed by calibration slope and intercept), Brier score, and decision analysis. An open access web application was developed for the best performing model and this web application can be found here: https://sorg-apps.shinyapps.io/spinemets/.

CONCLUSION

Machine learning algorithms are promising for prediction of postoperative outcomes in spinal oncology and these algorithms can be integrated into clinically useful decision tools. As the volume of data in oncology continues to grow, creation of learning systems and deployment of these systems as accessible tools may significantly enhance prognostication and management.

Minimally invasive lateral approaches for the treatment of spinal tumors: single-position surgery without the "flip"

Although primary tumors of the spine and neural elements are rare, metastatic disease to the spine is quite common. Traditionally, surgical treatment for spinal tumor patients involves open decompression with or without stabilization. The single-position minimally invasive (MIS) lateral approach, which has been recently described over the recent decade, allows simultaneous access to the anterior and posterior columns with the patient positioned in the lateral decubitus position. Herein, we review the application of single-position MIS lateral surgery for the treatment of spinal neoplasm. The aim was to review the evolution, operative technique, outcomes, and complications associated with MIS lateral approaches for spinal tumors. The history of spinal tumor diagnosis and management are reviewed and discussed as well as the author's experience and literature regarding spinal tumor treatment outcome and surgical complications, with particular attention to single-position, MIS lateral approaches. In addition, the author's surgical technique is outlined in detail for thoracic, thoracolumbar and lumbar tumors. Furthermore, there are specific indications and complications associated with the surgical treatment of spinal tumors, and the MIS, single-position lateral approach, when applied appropriately, allows for concurrent access to the anterior and posterior column while mitigating the complications associated with traditional, open posterior-based approaches. In the treatment of spinal neoplasms, the goals of surgery are dictated by a number of tumor-specific and patient-specific factors. Therefore, operative treatment of tumors in the future may be a consolidation of historical surgical techniques and MIS, single-position lateral approaches. Regardless, multidisciplinary management is imperative for the individualized treatment of the patient and optimization of outcome.

Vertebrectomy in metastatic spinal tumours: A 10 year, single-centre review of outcomes and survival

Metastatic disease to the vertebral column can cause spinal instability, neurological deterioration and pain. The present study was designed to provide insight into the cohort undergoing vertebrectomy for metastatic disease to the spinal column, assessing the associated morbidity, functional outcomes and survival. A retrospective review of 141 consecutive vertebrectomies for metastatic disease was undertaken. The procedures were performed between 2006 and 2016 at a single institution. Medical records were reviewed and data was obtained regarding primary malignancy, presenting symptoms, pre-operative chemotherapy or radiotherapy, Spinal Instability Neoplastic Score, neurological function, operative approach and duration, blood loss, transfusion requirement, complications, survival, delayed neurological deterioration and construct failure. Long-term follow-up data was available for 123 patients. Forty-two patients were alive at the time of review with a mean survival of 464 days. Post-operative neurological function was preserved or improved in 96.5% of patients. Five patients suffered a neurological deterioration post-operatively. The major complication rate was 19.8% with the most frequent complication being wound infection or dehiscence requiring revision. There were four inpatient deaths. Mean operative time was 240 min. Mean blood loss was 1490 mls. When assessing results by age, no significant difference with respect to complications, neurological outcomes or survival was demonstrated in patients over age 65. There was a significant reduction in survival and higher complication rates in patients who were non-ambulatory following vertebrectomy. Vertebrectomy is a safe and effective means of providing circumferential neural decompression and stabilization with an acceptable complication rate in patients with vertebral metastases, irrespective of age.

Sarcopenia Predicts Overall Survival in Patients with Lung, Breast, Prostate, or Myeloma Spine Metastases Undergoing Stereotactic Body Radiation Therapy (SBRT), Independent of Histology

BACKGROUND

Predicting survival of patients with spinal metastases would help stratify treatments from aggressive to palliation.

OBJECTIVE

To evaluate whether sarcopenia predicts survival in patients with lung, breast, prostate, or multiple myeloma spinal metastases.

METHODS

Psoas muscle measurements in patients with spinal metastasis were taken from computed tomography scans at 2 time points: at first episode of stereotactic body radiation therapy (SBRT) and from the most recent scan available. Overall survival and hazard ratios were calculated with multivariate cox proportional hazards regression analyses.

RESULTS

In 417 patients with spinal metastases, 40% had lung cancer, 27% breast, 21% prostate, and 11% myeloma. Overall survival was not associated with age, sex, ethnicity, levels treated, or SBRT volume. Multivariate analysis showed patients in the lowest psoas tertile had shorter survival (222 d, 95% CI = 185-323 d) as compared to the largest tertile (579 d, 95% CI = 405-815 d), (HR1.54, P = .005). Median psoas size as a cutoff value was also strongly predictive for survival (HR1.48, P = .002). Survival was independent of tumor histology. The psoas/vertebral body ratio was also successful in predicting overall survival independent of tumor histology and gender (HR1.52, P &lt; .01). Kaplan–Meier survival curves visually represent survival (P = .0005).

CONCLUSION

In patients with spine metastases, psoas muscle size as a hallmark of frailty/sarcopenia is an objective, simple, and effective way to identify patients who are at risk for shorter survival, regardless of tumor histology. This information can be used to help with surgical decision making in patients with advanced cancer, as patients with small psoas sizes are at higher risk of death.

Cerebrospinal fluid leaks after spine tumor resection: avoidance, recognition and management

Post-operative CSF leaks are a known complication of spine surgery in general, and patients undergoing surgical intervention for spinal tumors may be particularly predisposed due to the presence of intradural tumor and a number of other factors. Post-operative CSF leaks increase morbidity, lengthen hospital stays, prolong immobilization and subject patients to a number of associated complications. Intraoperative identification of unintended durotomies and effective primary repair of dural defects is an important first step in the prevention of post-operative CSF leaks, but in patients who develop post-operative pseudomeningoceles, durocutaneous fistulae or other CSF-leak-related sequelae, early recognition and secondary intervention are paramount to preventing further CSF-leak-related complications and achieving the best patient outcomes possible. In this article, the incidence, risk factors and complications of CSF leaks after spine tumor surgery are reviewed, with an emphasis on avoidance of post-operative CSF leaks, early post-operative identification and effective secondary intervention.

Hypoalbuminemia as an Independent Risk Factor for Perioperative Complications Following Surgical Decompression of Spinal Metastases

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

Malnutrition has been shown to be a risk factor for poor perioperative outcomes in multiple surgical subspecialties, but few studies have specifically investigated the effect of hypoalbuminemia in patients undergoing operative treatment of metastatic spinal tumors. The aim of this study was to assess the role of hypoalbuminemia as an independent risk factor for 30-day perioperative mortality and morbidity after surgical decompression of metastatic spinal tumors using the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database from 2011 to 2014.

METHODS

We identified 1498 adult patients in the ACS-NSQIP database who underwent laminectomy and excision of metastatic extradural spinal tumors. Patients were categorized into normoalbuminemic and hypoalbuminemic (ie, albumin level <3.5 g/dL) groups. Univariate and multivariate regression analyses were performed to examine the association between preoperative hypoalbuminemia and 30-day perioperative mortality and morbidity. Subgroup analysis was performed in the hypoalbuminemic group to assess the dose-dependent effect of albumin depletion.

RESULTS

Hypoalbuminemia was associated with increased risk of perioperative mortality, any complication, sepsis, intra- or postoperative transfusion, prolonged hospitalization, and non-home discharge. However, albumin depletion was also associated with decreased risk of readmission. There was an albumin level-dependent effect of increasing mortality and complication rates with worsening albumin depletion.

CONCLUSIONS

Hypoalbuminemia is an independent risk factor for perioperative mortality and morbidity following surgical decompression of metastatic spinal tumors with a dose-dependent effect on mortality and complication rates. Therefore, it is important to address malnutrition and optimize nutritional status prior to surgery.

Prognosticating outcomes and survival for patients with lumbar spinal metastases: Results of a bayesian regression analysis

OBJECTIVES

To assess the impact of surgical intervention on survival, ambulatory capacity, complications and readmissions following treatment for lumbar metastases.

PATIENTS AND METHODS

We identified all adult patients treated for lumbar metastases between 2005-2017. To limit the potential for inherent bias to influence determinations, we used principal component analysis to identify confounders to be included in multivariable testing. Multivariable logistic regression was performed, followed by Bayesian analysis to generate conservative estimates of effect size and 95% confidence intervals (CI). In a sensitivity test, analyses were repeated in a population where patients who died before they could initiate treatment were excluded.

RESULTS

In the period under study, we identified 571 patients who met inclusion criteria. Twenty-one percent of the cohort received a surgical intervention. Bayes regression indicated surgical intervention was independently associated with decreased mortality at 6-months (odds ratio [OR] 0.49; 95% CI 0.34, 0.68) and 1-year (OR 0.63; 95% CI 0.51, 0.76), along with lower odds of being non-ambulatory at 6-months following presentation (OR 0.29; 95% CI 0.18, 0.45). Surgery was also associated with increased odds of complications (OR 1.60; 95% CI 1.24, 2.06) and readmissions (OR 1.37; 95% CI 1.09, 1.72). Numerous clinical characteristics were found to be associated with the outcomes of interest including serum albumin, lung metastases and vertebral body collapse.

CONCLUSIONS

Given the favorable outcomes associated with the incorporation of surgery as a component of treatment, we believe that such interventions may be considered part of the treatment approach in patients with lumbar metastases.

Application of morphometrics as a predictor for survival in female patients with breast cancer spinal metastasis: a retrospective cohort study

BACKGROUND CONTEXT

The current standard of care for prediction of survival of cancer staging is based on TNM staging. However, for patients with spinal metastasis, who all have identical stage IV disease, identifying accurate prognostic markers of survival would allow better treatment stratification between more aggressive treatment strategies or palliation. Analytical morphometrics enables physicians to quantify patient frailty by measuring lean muscle mass. Morphometrics also predicts survival in patients with lung cancer metastases to the spine.

PURPOSE

Our study evaluates whether morphometrics is predictive of survival in patients with breast cancer spinal metastasis.

DESIGN

This is an observational retrospective cohort study.

PATIENT SAMPLE

This study includes female patients with breast cancer spinal metastases and patients who have undergone stereotactic body radiation therapy.

OUTCOME MEASURES

Overall survival was the primary outcome measure.

METHODS

Morphometric measurements of the psoas muscle were taken using computed tomography scans of the lumbar spine. We then stratified patients into tertiles based on the psoas muscle area.

RESULTS

We identified 118 patients, with a median survival of 104 days (95% confidence interval [CI]=73-157 days). Overall survival was not associated with age, chemotherapy, or number of levels radiated. Patients in the lowest tertile of psoas size had significantly shorter survival compared with the highest tertile (68 days versus 148 days, hazard ratio 1.76 [95% CI=1.08-2.89], p=.024). The shorter survival was also true for the lowest tertile versus the middle tertile (68 days versus 167 days, hazard ratio 1.95 [95% CI=1.19-3.19], p=.007). Kaplan-Meier survival curves were used to visually illustrate the differences in survival between different tertiles.

CONCLUSIONS

Morphometric analysis of the psoas muscle size in patients with breast cancer metastases to the spine was effective in identifying patients at risk of shorter survival. Further research is needed to validate these results, as well as to see if these methodologies can be applied to other cancer histologies.

Morphometrics predicts overall survival in patients with multiple myeloma spine metastasis: A retrospective cohort study

Background

Treatment strategies for spinal metastases for myeloma range from conservative measures (radiation and chemotherapy) to invasive (surgical). Identifying better predictors of overall survival (OS) would help in surgical decision making. Analytic morphometrics has been shown to predict survival in oncologic patients, and our study evaluates whether morphometrics is predictive of survival in patients with multiple myeloma (MM) spinal metastases.

Methods

For this observational retrospective cohort study, we identified 46 patients with MM spinal metastases who had undergone stereotactic body radiation therapy. OS was the primary outcome measure. Morphometric analysis of the psoas muscle was performed using computed tomography scans of the lumbar spine.

Results

OS was statistically correlated with age (P = 0.025), tumor burden (P = 0.023), and number of levels radiated (P = 0.029), but not with gender. Patients in the lowest tertile of average psoas size had significantly shorter survival compared to the highest tertile, hazard ratio (HZ) 6.87 (95% CI = 1.65-28.5, P = 0.008). When calculating the psoas size to vertebral body ratio and correlating this measure to OS, the lowest tertile again had significantly shorter OS compared to the highest tertile, HZ 6.87 (95% CI = 1.57-29.89, P = 0.010); the middle tertile also showed significantly shorter OS compared to the highest tertile, HZ 5.07 (95% CI = 1.34-19.10, P = 0.016). Kaplan-Meier survival curves were used to visually illustrate the differences in survival between different tertiles (Log-rank test P = 0.006).

Conclusions

Morphometric analysis successfully predicts long-term survival in patients with MM. More research is needed to validate these results and to see if these methodologies can be applied to other cancer histologies.

Age Stratification of 30-Day Postoperative Outcomes Following Excisional Laminectomy for Extradural Cervical and Thoracic Tumors

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

To evaluate age as an independent predictive factor for perioperative morbidity and mortality in patients undergoing surgical decompression for metastatic cervical and thoracic spinal tumors using the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database from 2011 to 2014.

METHODS

We identified 1673 adult patients undergoing excisional laminectomy of cervical and thoracic extradural tumors. Patients were stratified into quartiles based on age, with Q1 including patients aged 18 to 49 years, Q2 including patients aged 50 to 60 years, Q3 including patients aged 61 to 69 years, and Q4 including patients ≥70 years. Univariate and multivariate regression analyses were performed to examine the association between age and 30-day perioperative morbidity and mortality.

RESULTS

Age was an independent risk factor for 30-day venous thromboembolism (VTE) and reoperation. Patients in Q3 for age had nearly a 4 times increased risk of VTE than patients in Q1 (odds ratio [OR] 3.97; 95% CI 1.91-8.25; P < .001). However, there was no significant difference in VTE between patients in Q4 and Q1 (P = .069). Patients in Q2 (OR 1.99; 95% CI 1.06-3.74; P = .032) and Q4 (OR 2.18; 95% CI 1.06-4.52; P = .036) for age had a 2 times increased risk of reoperation compared with patients in Q1.

CONCLUSIONS

Age was an independent predictive factor for perioperative VTE and reoperation, but there was no clear age-dependent relationship between increasing age and the risk of these perioperative complications.

Stereotactic body radiation therapy for lung, spine and oligometastatic disease: current evidence and future directions

Stereotactic body radiation therapy (SBRT) also referred to as stereotactic ablative radiotherapy (SABR), is a technique which has emerged over the past two decades due to improvements in radiation technology. Unlike conventional external beam radiotherapy (cEBRT) which traditionally delivers radiation in small doses [approximately 2 Gray (Gy) per fraction] over several weeks, SBRT, typically delivered in one to eight fractions, is a technique whereby potentially ablative doses of radiotherapy (usually 7.5-20 Gy per fraction) can be delivered with steeper dose gradients and sub millimetre precision, minimising risk to surrounding normal tissues. The potential benefits of excellent tumor control with low toxicity has led to the increasing use of SBRT in a number of clinical situations. Due to compelling evidence, SBRT is now the treatment of choice for medically inoperable patients with peripherally located stage I non-small cell lung cancer (NSCLC). Controversy remains however as to its efficacy and safety for central or ultra-central lung tumors. The evidence base supporting the use of SBRT as a novel treatment for spinal metastases and oligometastases is rapidly expanding but challenges remain in these difficult patient populations. In an era where targeted therapy and improved systemic treatments for stage IV cancer have resulted in increased disease-free survival, and our knowledge of the oligometastatic state is ever expanding, using SBRT to treat metastatic disease and gain durable local control is increasingly desirable. Several randomized trials are currently underway and are sure to provide valuable information on the benefit and utility of SBRT across many tumor sites including early-stage NSCLC, spinal metastases and oligometastatic disease. Recognizing the evolving role of SBRT in clinical practice, this paper provides a critical review of recent developments in each of these areas particularly highlighting the challenges facing clinicians and discusses potential areas for future research.

The Impact of Metastatic Spinal Tumor Location on 30-Day Perioperative Mortality and Morbidity After Surgical Decompression

STUDY DESIGN

A retrospective cohort study from 2011 to 2014 was performed using the American College of Surgeons National Surgical Quality Improvement Program database.

OBJECTIVE

The purpose of this study was to assess the impact of tumor location in the cervical, thoracic, or lumbosacral spine on 30-day perioperative mortality and morbidity after surgical decompression of metastatic extradural spinal tumors.

SUMMARY OF BACKGROUND DATA

Operative treatment of metastatic spinal tumors involves extensive procedures that are associated with significant complication rates and healthcare costs. Past studies have examined various risk factors for poor clinical outcomes after surgical decompression procedures for spinal tumors, but few studies have specifically investigated the impact of tumor location on perioperative mortality and morbidity.

METHODS

We identified 2238 patients in the American College of Surgeons National Surgical Quality Improvement Program database who underwent laminectomy for excision of metastatic extradural tumors in the cervical, thoracic, or lumbosacral spine. Baseline patient characteristics were collected from the database. Univariate and multivariate regression analyses were performed to examine the association between spinal tumor location and 30-day perioperative mortality and morbidity.

RESULTS

On univariate analysis, cervical spinal tumors were associated with the highest rate of pulmonary complications. Multivariate regression analysis demonstrated that cervical spinal tumors had the highest odds of multiple perioperative complications. However, thoracic spinal tumors were associated with the highest risk of intra- or postoperative blood transfusion. In contrast, patients with metastatic tumors in the lumbosacral spine had lower odds of perioperative mortality, pulmonary complications, and sepsis.

CONCLUSION

Tumor location is an independent risk factor for perioperative mortality and morbidity after surgical decompression of metastatic spinal tumors. The addition of tumor location to existing prognostic scoring systems may help to improve their predictive accuracy.

LEVEL OF EVIDENCE

3.

Minimally invasive versus conventional spine surgery for vertebral metastases: a systematic review of the evidence

One of the major determinants of surgical candidacy in patients with symptomatic spinal metastases is the ability of the patient to tolerate the procedure-associated morbidity. In other pathologies, minimally invasive (MIS) procedures have been suggested to have lower intra-operative morbidity while providing similar outcomes. We conducted a systematic review of the PubMed library searching for articles that directly compared the operative and post-operative outcomes of patients treated for symptomatic spinal metastases. Inclusion criteria were articles reporting two or more cases of patients >18 years old treated with MIS or open approaches for spinal metastases. Studies reporting results in spinal metastases patients that could not be disentangled from other pathologies were excluded. Our search returned 1,568 articles, of which 9 articles met the criteria for inclusion. All articles were level III evidence. Patients treated with MIS approaches tended to have lower intraoperative blood loss, shorter operative times, shorter inpatient stays, and fewer complications relative to patients undergoing surgeries with conventional approaches. Patients in the MIS and open groups had similar pain improvement, neurological improvement, and functional outcomes. Recent advances in MIS techniques may reduce surgical morbidity while providing similar symptomatic improvement in patients treated for spinal metastases. As a result, MIS techniques may expand the pool of patients with spinal metastases who are candidates for operative management.

Prognostic Factors of Surgical Complications and Overall Survival of Patients with Metastatic Spinal Tumor

OBJECTIVE

Oncologic treatments increase the incidence of spinal metastases. Surgical treatment of spinal metastases results in a high complication rate, which must set against the expected benefits. The aim of this article was to study the effect of several prognostic factors on surgical complications and survival time using an extended database of patients with spinal metastases.

METHODS

This retrospective study comprised 337 patients with spinal metastases who were surgically treated between 2008 and 2015. Demographic and clinical features, oncologic histories, surgical interventions, and end results were collected. Descriptive statistical methods were used to analyze the cohort of patients. Kaplan-Meier formula and log-rank test were used to examine overall survival times.

RESULTS

Median overall survival time was 222 days (range, 175-274 days). Age, preoperative motor disorders, preoperative Frankel grade categories, Karnofsky performance scale, type of primary tumor, and presence of internal metastasis had a significant negative effect on overall survival. Complications such as bleeding or need for intensive care could be predicted preoperatively based on preoperative performance status, type of primary tumor, affected vertebral levels, and type of surgical interventions.

CONCLUSIONS

Spinal metastatic disease is a challenging surgical problem. If the exact prognostic factors are known preoperatively, surgical outcome and overall survival can be predicted more precisely. Our results could provide a basis for a future multicenter prospective study to determine the best treatment protocol for patients with spinal metastases.

Red Blood Cell Transfusion Need for Elective Primary Posterior Lumbar Fusion in A High-Volume Center for Spine Surgery

(1) Background: This study evaluated the perioperative red blood cell (RBC) transfusion need and determined predictors for transfusion in patients undergoing elective primary lumbar posterior spine fusion in a high-volume center for spine surgery. (2) Methods: Data from all patients undergoing spine surgery between 1 January 2014 and 31 December 2016 were reviewed. Patients’ demographics and comorbidities, perioperative laboratory results, and operative time were analyzed in relation to RBC transfusion. Multivariate logistic regression analysis was performed to identify the predictors of transfusion. (3) Results: A total of 874 elective surgeries for primary spine fusion were performed over the three years. Only 54 cases (6%) required RBC transfusion. Compared to the non-transfused patients, transfused patients were mainly female (p = 0.0008), significantly older, with a higher ASA grade (p = 0.0002), and with lower pre-surgery hemoglobin (HB) level and hematocrit (p < 0.0001). In the multivariate logistic regression, a lower pre-surgery HB (OR (95% CI) 2.84 (2.11–3.82)), a higher ASA class (1.77 (1.03–3.05)) and a longer operative time (1.02 (1.01–1.02)) were independently associated with RBC transfusion. (4) Conclusions: In the instance of elective surgery for primary posterior lumbar fusion in a high-volume center for spine surgery, the need for RBC transfusion is low. Factors anticipating transfusion should be taken into consideration in the patient’s pre-surgery preparation.

Spinal Metastasis of Unknown Primary Accompanied by Neurologic Deficit or Vertebral Instability

BACKGROUND AND OBJECTIVE

Spinal bone metastases are common. They are mostly localized to the lumbar, thoracic, and cervical spine. The most common primaries to result in spinal metastases include lung, breast, and prostate carcinomas in adults as opposed to leukemia, Ewing sarcoma, rhabdomyosarcoma, and neuroblastoma in children. In patients diagnosed with cancer, bone metastases are found in 40% and spinal metastases in 10%. In this study, we reviewed 25 patients diagnosed with a spinal metastasis of unknown primary who presented with low back pain or acute-onset neurologic deficits and underwent operative treatment.

METHODS

The retrospective study included 25 patients with a spinal metastasis of unknown primary who presented to our clinic with acute-onset vertebral fracture or neurologic deficit. Statistical descriptions were obtained for each patient. Survival analysis was performed using the Kaplan-Meier method.

RESULTS

The 25 patients included 17 men (68%) and 8 women (32%), with a mean age of 55 years (range, 14-81 years). Eleven patients (44%) presented with varying degrees of motor deficits ranging from flaccid paralysis to paraplegia. Motor deficits were completely reversed in 4 patients postoperatively. The tumors were localized to the upper thoracic spine (T1-4) in 2 patients, in the midthoracic spine (T5-8) in 2 patients, in the lower thoracic spine (T9-12) in 8 patients, in the cervical 7 in 1 patient, and in the lumbar spine in 12 patients. In 10 patients, the tumor affected multiple spinal regions. Nonosseous tumors were not present in 10 patients. Ten patients had an extradural tumor. Costal involvement was detected in 2 patients. The tumors were pathologically identified as lung cancer (n = 3), lymphoma (n = 5), breast cancer (n = 3), gastric cancer (n = 2), liver cancer (n = 2), prostate cancer (n = 2), renal cell carcinoma (n = 2), malignant melanoma (n = 1), plasmacytoma (n = 1), bladder cancer (n = 1), paraganglioma (n = 1), Ewing sarcoma (n = 1), and yolk sac carcinoma (n = 1). Posterior instrumentation was performed in patients with instability. In addition, decompression was performed in patients with neurologic deficit.

CONCLUSIONS

Considering that 10% of patients with cancer are diagnosed by vertebral metastasis, presence of malignancy should be suspected and a detailed examination should be performed in patients presenting with vertebral fractures caused by no or minor trauma. Moreover, in patients presenting with neurologic deficit, soft tissue metastases leading to spinal cord compression should be kept in mind and further examinations should be promptly administered.

Application of morphometric analysis to patients with lung cancer metastasis to the spine: a clinical study

OBJECTIVE Predicting the survival rate for patients with cancer is currently performed using the TNM Classification of Malignant Tumors (TNM). Identifying accurate prognostic markers of survival would allow better treatment stratification between more aggressive treatment strategies or palliation. This is especially relevant for patients with spinal metastases, who all have identical TNM staging and whose surgical decision-making is potentially complex. Analytical morphometrics quantifies patient frailty by measuring lean muscle mass and can predict risk for postoperative morbidity after lumbar spine surgery. This study evaluates whether morphometrics can be predictive of survival in patients with spinal metastases. METHODS Utilizing a retrospective registry of patients with spinal metastases who had undergone stereotactic body radiation therapy, the authors identified patients with primary lung cancer. Morphometric measurements were taken of the psoas muscle using CT of the lumbar spine. Additional morphometrics were taken of the L-4 vertebral body. Patients were stratified into tertiles based on psoas muscle area. The primary outcome measure was overall survival, which was measured from the date of the patient's CT scan to date of death. RESULTS A total of 168 patients were identified, with 54% male and 54% having multiple-level metastases. The median survival for all patients was 185.5 days (95% confidence interval [CI] 146-228 days). Survival was not associated with age, sex, or the number of levels of metastasis. Patients in the smallest tertile for the left psoas area had significantly shorter survival compared with a combination of the other two tertiles: 139 days versus 222 days, respectively, hazard ratio (HR) 1.47, 95% CI 1.06-2.04, p = 0.007. Total psoas tertiles were not predictive of mortality, but patients whose total psoas size was below the median size had significantly shorter survival compared with those greater than the median size: 146 days versus 253.5 days, respectively, HR 1.43, 95% CI 1.05-1.94, p = 0.025. To try to differentiate small body habitus from frailty, the ratio of psoas muscle area to vertebral body area was calculated. Total psoas size became predictive of mortality when normalized to vertebral body ratio, with patients in the lowest tertile having significantly shorter survival (p = 0.017). Left psoas to vertebral body ratio was also predictive of mortality in patients within the lowest tertile (p = 0.021). Right psoas size was not predictive of mortality in any calculations. CONCLUSIONS In patients with lung cancer metastases to the spine, morphometric analysis of psoas muscle and vertebral body size can be used to identify patients who are at risk for shorter survival. This information should be used to select patients who are appropriate candidates for surgery and for the tailoring of oncological treatment regimens.

Massive blood loss in elective spinal and orthopedic surgery: Retrospective review of intraoperative transfusion strategy

OBJECTIVE

To evaluate the perioperative dynamics of hematologic changes and transfusion ratio in patients undergoing a major spinal surgery accompanied with massive bleeding defined as blood loss >5 liters.

DESIGN

Retrospective cohort study.

SETTING

Operating room of a university-affiliated hospital.

PATIENTS

Adult patients who underwent elective neurosurgical, orthopedic, or combined spinal surgical procedure between 2008 and 2012.

METHODS

Patients who underwent a major spinal or orthopedic surgery and who experienced major bleeding (>5 L) during surgery were identified and selected for final analysis. The following information was analyzed: demographics, clinical diagnoses, hematologic parameters, estimated intraoperative blood loss, blood product transfusions, and survival 1 year after surgery.

RESULTS

During the study period, 25 patients, who underwent 28 spinal procedures, experienced intraoperative blood loss >5 L. Mean patient age was 50.5 years and 56.4% were males. The majority of patients underwent procedures to manage spinal metastases. Median estimated intraoperative blood loss was 11.25 L (IQR 6.35-22 L) and median number of units (U) transfused was 24.5 U (IQR 14.0-32.5 U) of packed red blood cells (RBCs), 24.5 U (IQR 14.0-34.0 U) of fresh frozen plasma (FFP), and 4.5 U (IQR 3.0-11.5 U) of platelets (PLTs). The blood product transfusion ratio was 1 and 4 for RBC:FFP, and RBC:PLT, respectively. Hematocrit, hemoglobin, PLTs, partial thromboplastin, prothrombin time, INR, and, fibrinogen varied significantly throughout the procedures. However, acid-base status did not change significantly during surgery. Patients' survival at 1 year was 79.17%.

CONCLUSION

Our results indicate that a 1:1 RBC:FFP and 4:1 RBC:PLT transfusion ratio was associated with significant intraoperative variations in coagulation variables but stable intraoperative acid-base parameters. This transfusion ratio helped clinicians to achieve postoperative coagulation parameters not significantly different to those at baseline. Future studies should assess if more liberal transfusion strategies or point of care monitoring might be warranted in patients undergoing spinal surgery at risk of major blood loss.

Is there a correlation between the spinal instability neoplastic score and mechanical pain in patients with metastatic spinal cord compression? A prospective cohort study

INTRODUCTION

The decision for selecting patients for surgical treatment of metastatic spinal cord compression (MSCC) is challenging even for experienced surgeons. Recently, the spinal instability neoplastic score (SINS) has been proposed to help surgeons in the evaluation of spinal stability in the setting of spinal metastases. This study aimed to evaluate the correlation between SINS and preoperative visual analog scale (VAS), as well as the pre- and post-operative association of the VAS and neurological function.

METHODS

A prospective cohort study was conducted in a tertiary referral cancer center. Seventy-nine patients with MSCC were surgically treated from June 2012 to March 2015. Pain status before and after surgery was assessed using VAS score, and neurological status was evaluated using the American Spine Injury Association Impairment Scale (AIS) before and after surgery. Pain was classified as VAS (0-4) none or mild pain; VAS (5-8) moderate pain; and VAS (9-10) as severe pain. Neurological function was scored as AIS A: Complete deficits, AIS B-D: Incomplete deficits, AIS E: Neurologically intact. SINS degrees were classified as 0-6-stable; 7-12 potentially unstable, and 13-18-unstable. Spearman's correlation coefficient test was utilized for correlation between pain and SINS; Chi-square association test was utilized for evaluating pre- and post-operative pain and AIS, as well as the association between SINS and tumor types.

RESULTS

A higher SINS correlates with severe mechanical pain preoperatively (ρ = 0.38, P = 0.001); surgical procedure improved neurological function (P = 0.0001), and decrease pain (P = 0.84). Finally, a higher SINS was also associated with osteolytic tumors (P = 0.03).

CONCLUSIONS

The SINS correlates with mechanical pain. Surgery provides a significant improvement in pain and neurological status, especially in patients who presented higher SINS scores and some degree of preoperative neurological function.

Perioperative blood transfusion: does it influence survival and cancer progression in metastatic spine tumor surgery?

BACKGROUND

Despite advances in surgical techniques for spinal metastases, there is often substantial blood loss, resulting in patients requiring blood transfusion during the perioperative period. Allogeneic blood transfusion (ABT) has been the main replenishment method for lost blood. However, the impact of ABT on cancer-related outcomes has been controversial in various studies. We aimed to evaluate the influence of perioperative ABT on disease progression and survival in patients undergoing metastatic spinal tumor surgery (MSTS).

STUDY DESIGN AND METHODS

We conducted a retrospective study that included 247 patients who underwent MSTS at a single tertiary institution between 2005 and 2014. The impact of using perioperative ABT (either exposure to or quantities of transfusion) on disease progression and survival was assessed using Cox regression analyses while adjusting for potential confounding variables.

RESULTS

Of 247 patients, 133 (54%) received ABT. The overall median number of blood units transfused was 2 (range, 0-10 units). Neither blood transfusion exposure nor quantities of transfusion were associated with overall survival (hazard ratio [HR], 1.15 [p = 0.35] and 1.10 [p = 0.11], respectively) and progression-free survival (HR, 0.87 [p = 0.18] and 0.98 [p = 0.11], respectively). The factors that influenced overall survival were primary tumor type and preoperative Eastern Cooperative Oncology Group performance status, whereas primary tumor type was the only factor that had an impact on progression-free survival.

CONCLUSIONS

This is the first study providing evidence that disease progression and survival in patients who undergo MSTS are less likely to be influenced by perioperative ABT. The worst oncologic outcomes are more likely to be caused by the clinical circumstances necessitating blood transfusion, but not transfusion itself. However, because ABT can have a propensity toward developing postoperative infections, including surgical site infection, the use of patient blood management interventions would be worthwhile rather than relying solely on ABTs for these patients, if and whenever possible.

Changing the Adverse Event Profile in Metastatic Spine Surgery: An Evidence-Based Approach to Target Wound Complications and Instrumentation Failure

STUDY DESIGN

Systematic review.

OBJECTIVE

To identify risk factors and preventive methods for wound complications and instrumentation failure after metastatic spine surgery.

SUMMARY OF BACKGROUND DATA

We focused on two postoperative complications of metastatic spine tumor surgery: wound complications and instrumentation failure and preventive measures.

METHODS

We performed a systematic review of the literature from 1980 to 2015. The articles were analyzed for the presence of documented infection and/or wound complications and instrumentation failure.

RESULTS

Forty articles met our inclusion criteria for wound complications and prevention. There is very low level of evidence that preoperative radiation, preoperative neurological deficit, revision procedures, and posterior approaches can contribute to wound complications (infections, wound dehiscence). There is very low level of evidence that plastic surgery soft tissue reconstruction, intrawound vancomycin powder, and percutaneous pedicle screws may prevent postoperative wound complications. Fourteen articles met our inclusion criteria for instrumentation failure. There is very low level of evidence that constructs greater than six levels, positive sagittal balance, preoperative radiation, and history of chest wall resection can contribute to implant failures.

CONCLUSION

• For patients undergoing revision metastatic spine tumor surgery, plastic surgery should perform the soft tissue reconstruction (strong recommendation/very low quality of evidence).• For patients undergoing metastatic spine tumor surgery, plastic surgery may perform immediate soft tissue reconstruction (weak recommendation/very low quality of evidence).• For patients undergoing metastatic spine tumor surgery, intrawound vancomycin can be applied to decrease the risk of postoperative wound infections (weak recommendation/very low quality of evidence).• For patients undergoing metastatic spine tumor surgery, percutaneous pedicle screws can be placed to decrease the risk of postoperative wound complications (weak recommendation/very low quality of evidence).• Instrumentation failure risk factors include constructs greater than six levels, positive sagittal balance, preoperative radiation, and history of chest wall resections (weak recommendation/very low quality of evidence).

LEVEL OF EVIDENCE

N/A.

Magnetic Resonance Imaging of Spinal Emergencies

Like the brain, the spinal cord is subject to trauma, infection, ischemia, hemorrhage, and compression. Early diagnosis is the key to preventing significant morbidity in the form of permanent disability. MR imaging is the gold standard for assessing acute injury to the spinal cord, intervertebral discs, ligaments, and surrounding soft tissues. In this article we systematically review the MRI findings in spinal cord trauma, ligamentous injury, epidural hematoma, epidural abscess, and metastatic disease.

Thirty-day readmission and reoperation after surgery for spinal tumors: a National Surgical Quality Improvement Program analysis

OBJECTIVE

The goal of this study was to use a large national registry to evaluate the 30-day cumulative incidence and predictors of adverse events, readmissions, and reoperations after surgery for primary and secondary spinal tumors.

METHODS

Data from adult patients who underwent surgery for spinal tumors (2011–2014) were extracted from the prospective National Surgical Quality Improvement Program (NSQIP) registry. Multivariable logistic regression was used to evaluate predictors of reoperation, readmission, and major complications (death, neurological, cardiopulmonary, venous thromboembolism [VTE], surgical site infection [SSI], and sepsis). Variables screened included patient age, sex, tumor location, American Society of Anesthesiologists (ASA) physical classification, preoperative functional status, comorbidities, preoperative laboratory values, case urgency, and operative time. Additional variables that were evaluated when analyzing readmission included complications during the surgical hospitalization, hospital length of stay (LOS), and discharge disposition.

RESULTS

Among the 2207 patients evaluated, 51.4% had extradural tumors, 36.4% had intradural extramedullary tumors, and 12.3% had intramedullary tumors. By spinal level, 20.7% were cervical lesions, 47.4% were thoracic lesions, 29.1% were lumbar lesions, and 2.8% were sacral lesions. Readmission occurred in 10.2% of patients at a median of 18 days (interquartile range [IQR] 12–23 days); the most common reasons for readmission were SSIs (23.7%), systemic infections (17.8%), VTE (12.7%), and CNS complications (11.9%). Predictors of readmission were comorbidities (dyspnea, hypertension, and anemia), disseminated cancer, preoperative steroid use, and an extended hospitalization. Reoperation occurred in 5.3% of patients at a median of 13 days (IQR 8–20 days) postoperatively and was associated with preoperative steroid use and ASA Class 4–5 designation. Major complications occurred in 14.4% of patients: the most common complications and their median time to occurrence were VTE (4.5%) at 9 days (IQR 4–19 days) postoperatively, SSIs (3.6%) at 18 days (IQR 14–25 days), and sepsis (2.9%) at 13 days (IQR 7–21 days). Predictors of major complications included dependent functional status, emergency case status, male sex, comorbidities (dyspnea, bleeding disorders, preoperative systemic inflammatory response syndrome, preoperative leukocytosis), and ASA Class 3–5 designation (p < 0.05). The median hospital LOS was 5 days (IQR 3–9 days), the 30-day mortality rate was 3.3%, and the median time to death was 20 days (IQR 12.5–26 days).

CONCLUSIONS

In this NSQIP analysis, 10.2% of patients undergoing surgery for spinal tumors were readmitted within 30 days, 5.3% underwent a reoperation, and 14.4% experienced a major complication. The most common complications were SSIs, systemic infections, and VTE, which often occurred late (after discharge from the surgical hospitalization). Patients were primarily readmitted for new complications that developed following discharge rather than exacerbation of complications from the surgical hospital stay. The strongest predictors of adverse events were comorbidities, preoperative steroid use, and higher ASA classification. These models can be used by surgeons to risk-stratify patients preoperatively and identify those who may benefit from increased surveillance following hospital discharge.

Assessing the utility of a clinical prediction score regarding 30-day morbidity and mortality following metastatic spinal surgery: the New England Spinal Metastasis Score (NESMS)

BACKGROUND CONTEXT

The New England Spinal Metastasis Score (NESMS) was recently proposed to help predict 1-year survival following surgery for spinal metastases. Its ability to predict short-term outcomes, including 30-day morbidity, mortality, and hospital length of stay, has not been evaluated.

PURPOSE

Assess the capacity of NESMS to predict 30-day morbidity and mortality, as well as hospital length of stay, following surgery for spinal metastases.

STUDY DESIGN

Validation study.

PATIENT SAMPLE

All patients who had undergone spinal surgery with a history of metastatic spinal disease within the National Surgical Quality Improvement Program (NSQIP; 2007-2013).

OUTCOME MEASURE

Mortality, complications, failure to rescue, and length of stay.

METHODS

Demographic, oncologic, laboratory, and surgical data were obtained from the NSQIP. All patients were assigned an NESMS score (0-3). The effect of the NESMS score on the outcomes of interest was assessed using multivariable logistic regression and negative binomial regression that controlled for confounders. Final model discrimination and calibration were assessed using the c-statistic and Hosmer-Lemeshow test, respectively. Internal validation was performed using a bootstrapping procedure.

RESULTS

NSQIP data on 776 patients were included in this analysis. The 30-day mortality rate was 11% (N=87), and 51% of patients (N=395) sustained one or more complications. The final adjusted model demonstrated that the NESMS was a statistically significant predictor of 30-day mortality (p<.001), major systemic complications (p<.001), and failure to rescue (p=.03) following metastatic spinal surgery. Patients with an NESMS score of 3 had an 89% reduction in mortality (95% confidence interval [CI]: 0.04, 0.31), a 74% reduction in major systemic complications (95% CI: 0.11, 0.62), and an 88% reduction in failure to rescue (95% CI: 0.03, 0.47) as compared with those with a score of 0. The final model explained 71% of the variation in 30-day mortality. Findings were unchanged in the bootstrap analysis performed among 77,600 patient replicates.

CONCLUSION

This study demonstrates the clinical accuracy of the NESMS score for predicting short-term major morbidity and mortality following metastatic spinal surgery. The success of this score in an independent cohort of patients collected from centers across the United States indicates its potential for translation to clinical practice.

Survival and Clinical Outcomes in Surgically Treated Patients With Metastatic Epidural Spinal Cord Compression: Results of the Prospective Multicenter AOSpine Study

PURPOSE

Although surgery is used increasingly as a strategy to complement treatment with radiation and chemotherapy in patients with metastatic epidural spinal cord compression (MESCC), the impact of surgery on health-related quality of life (HRQoL) is not well established. We aimed to prospectively evaluate survival, neurologic, functional, and HRQoL outcomes in patients with MESCC who underwent surgical management.

PATIENTS AND METHODS

One hundred forty-two patients with a single symptomatic MESCC lesion who were treated surgically were enrolled onto a prospective North American multicenter study and were observed at least up to 12 months. Clinical data, including Brief Pain Inventory, ASIA (American Spinal Injury Association) impairment scale, SF-36 Short Form Health Survey, Oswestry Disability Index, and EuroQol 5 dimensions (EQ-5D) scores, were obtained preoperatively, and at 6 weeks and 3, 6, 9, and 12 months postoperatively.

RESULTS

Median survival time was 7.7 months. The 30-day and 12-month mortality rates were 9% and 62%, respectively. There was improvement at 6 months postoperatively for ambulatory status (McNemar test, P < .001), lower extremity and total motor scores (Wilcoxon signed rank test, P < .001), and at 6 weeks and 3, 6, and 12 months for Oswestry Disability Index, EQ-5D, and pain interference (paired t test, P < .013). Moreover, at 3 months after surgery, the ASIA impairment scale grade was improved (Stuart-Maxwell test P = .004). SF-36 scores improved postoperatively in six of eight scales. The incidence of wound complications was 10% and 2 patients required a second surgery (screw malposition and epidural hematoma).

CONCLUSION

Surgical intervention, as an adjunct to radiation and chemotherapy, provides immediate and sustained improvement in pain, neurologic, functional, and HRQoL outcomes, with acceptable risks in patients with a focal symptomatic MESCC lesion who have at least a 3 month survival prognosis.

Minimally Invasive Muscle Sparing Posterior-Only Approach for Lumbar Circumferential Decompression and Stabilization to Treat Spine Metastasis--Technical Report

OBJECTIVE

Palliative tumor resection and subsequent stabilization are important for maximizing function and quality of life for patients suffering from spinal metastases. However, traditional operative techniques for spinal metastases with vertebral body destruction involve extensive soft tissue dissection. In the lumbar spine, open 2-staged spine procedures are routinely required with an anterior retroperitoneal approach for corpectomy and cage insertion and posterior decompression and stabilization with pedicle screws and rods. Both stages require extensive soft tissue dissection that results in significant surgical morbidity, long recovery time, and subsequent delay in initiating postoperative chemoradiotherapy, as well as initially hampering patients' overall quality of life. A minimally invasive approach is desirable for achieving spinal stability, pain control, functional recovery, rapid initiation of adjuvant therapies, and overall patient satisfaction, especially in patients whose medical and surgical therapies are aimed at palliation rather than cure.

PRESENTATION

A 59-year-old man with renal cell carcinoma and a known L1 vertebral body metastasis presented with severe progressive low back pain and was found to have a pathologic L1 vertebral body fracture with focal kyphosis.

INTERVENTION

Here, we describe a minimally invasive muscle-sparing, posterior-only approach for L1 transpedicular hemicorpectomy and expandable cage placement, L1 laminectomy, and T11-L3 posterior instrumented stabilization. The surgical corridor was achieved through the Wiltse muscle plane between the multifidus and longissimus muscles so that minimal muscle detachment was required to achieve transpedicular access to the anterior and middle spinal columns. The L1 nerve root was completely skeletonized to allow adequate lumbar hemicorpectomy, tumor resection, and expandable titanium cage insertion. Lastly, percutaneous pedicle screws and rods were inserted from T11 to L3 for stabilization.

RESULT

The patient tolerated the procedure well with no complications and less than 200 mL estimated blood loss. Postoperative computed tomography revealed restoration of intervertebral height and adequate tumor resection with excellent placement of the expandable cage and posterior construct. The patient was discharged on postoperative day 4 and had nearly no back pain 3 weeks after surgery. Adjuvant therapies were started soon after. At the 6-month follow-up, the patient required minimal narcotic pain medication. Computed tomography scan demonstrated stable hardware with no evidence of failure.

CONCLUSION

A minimally invasive muscle-sparing, posterior-only approach is a promising surgical strategy for 360-degree decompression and stabilization for the treatment of lumbar spinal metastases with minimized blood loss, muscle detachment and postoperative pain, and fast postoperative recovery and initiation of adjuvant therapy.