Evidence-based review of the surgical management of vertebral column metastatic disease

Minimal invasive fixation following with radiotherapy for radiosensitive unstable metastatic spine

BACKGROUND

Minimally invasive surgery (MIS) has become a feasible option for patients with spinal metastasis, but the effectiveness of percutaneous pedicle screw fixation (PPSF) without decompression in patients with severe cord compression remains unknown. We compared PPSF without decompression with debulking surgery in patients with radiosensitive, unstable, metastatic thoracolumbar spinal cord compression.

METHODS

A retrospective study of surgically treated spinal metastasis and spinal cord compression patients was conducted between October 2014 and June 2019. Demographic and pre- and postoperative data were collected and compared between patients treated with minimally invasive percutaneous fixation and external beam radiotherapy (EBRT) (the PPSF group) and those treated with debulking surgery (the debulking group).

RESULTS

We included 50 patients in this study. The PPSF group had a significantly shorter operative time (143.56 ± 49.44 min vs. 181.47 ± 40.77 min; p < .01), significantly lower blood loss (116.67 ± 109.92 mL vs. 696.55 ± 519.43 mL; p < .01), and significantly shorter hospital stay (11.90 ± 9.69 vs. 25.35 ± 20.65; p <0.01) than did the debulking group. No significant differences were observed between the groups in age, sex, spinal instability neoplastic score, ESCC, Tomita scores, numeric rating scale scores, American Spinal Injury Association Impairment Scale scores, survival rates, and complication rates. Postoperative neurologic function and decrease in pain were similar between the groups.

CONCLUSION

The PPSF group had a shorter operation time, shorter length of hospital stay, and less blood loss than did the debulking group. PPSF followed by EBRT is pain relieving, relatively safe and appropriate as palliative therapy.

How to Target Spinal Metastasis in Experimental Research: An Overview of Currently Used Experimental Mouse Models and Future Prospects

The spine is one of the organs that is most affected by metastasis in cancer patients. Since the control of primary tumor is continuously improving, treatment of metastases is becoming one of the major challenges to prevent cancer-related death. Due to the anatomical proximity to the spinal cord, local spread of metastasis can directly cause neurological deficits, severely limiting the patient’s quality of life. To investigate the underlying mechanisms and to develop new therapies, preclinical models are required which represent the complexity of the multistep cascade of metastasis. Current research of metastasis focuses on the formation of the premetastatic niche, tumor cell dormancy and the influence and regulating function of the immune system. To unveil whether these influence the organotropism to the spine, spinal models are irreplaceable. Mouse models are one of the most suitable models in oncologic research. Therefore, this review provides an overview of currently used mouse models of spinal metastasis. Furthermore, it discusses technical aspects clarifying to what extend these models can picture key steps of the metastatic process. Finally, it addresses proposals to develop better mouse models in the future and could serve as both basis and stimulus for researchers and clinicians working in this field.

Comparison of Minimally Invasive Total versus Subtotal Resection of Spinal Tumors: A Systematic Review and Meta-Analysis

OBJECTIVE

With the advent of minimally invasive techniques, minimally invasive spine surgery (MISS) has become a realistic option for many spine cases. This study aims to evaluate the operative and clinical outcomes of MISS for total versus subtotal tumor resection from current evidence.

METHODS

A literature search was performed using the search term (Minimally invasive surgery OR MIS) AND (spine tumor OR spinal tumor). Studies including both minimally invasive total and subtotal resection cases with operative or clinical data were included.

RESULTS

Seven studies describing 159 spinal tumor cases were included. Compared with total resection, subtotal resection showed no significant differences in surgical time (mean difference (MD), 9.44 minutes; 95% confidence interval [CI], -47.66 to 66.55 minutes; P = 0.37), surgical blood loss (MD, -84.72 mL; 95% CI, -342.82 to 173.39 mL; P = 0.34), length of stay (MD, 1.38 days; 95% CI, -0.95 to 3.71 days; P = 0.17), and complication rate (odds ratio, 9.47; 95% CI, 0.34-263.56; P = 0.12). Pooled analyses with the random-effects model showed that neurologic function improved in 89% of patients undergoing total resection, whereas neurologic function improved in 61% of patients undergoing subtotal resection.

CONCLUSIONS

Our analyses show that there is no significant difference in operative outcomes between total and subtotal resection. Patients undergoing total resection showed slightly better improvement in neurologic outcomes compared with patients undergoing subtotal resection. Overall, this study suggests that both total and subtotal resection may result in comparable outcomes for patients with spinal tumors. However, maximal safe resection remains the ideal treatment because it provides the greatest chance of long-term benefit.

Gender disparities in clinical presentation, treatment, and outcomes in metastatic spine disease

BACKGROUND

The incidence of metastatic spine disease (MSD) is increasing among cancer patients. Given the poor outcomes and high rates of morbidity associated with MSD, it is important to determine demographic factors that could impact interventions and outcomes for this patient population. The objectives of this study were to compare in-hospital mortality and complication rates, clinical presentation, and interventions between female and male patients diagnosed with MSD.

METHODS

Patient data were collected from the United States National Inpatient Sample (NIS) database from the years 2012-2014. Descriptive statistics were used to compare data from 51,800 cases; subsequently, multivariable logistic regression analyses were conducted to assess the effect of gender on outcomes.

RESULTS

Males had significantly higher rates of in-hospital mortality (OR 1.30; 95 % CI 1.09-1.56, p = 0.004) and were more likely to have received surgical intervention than females (OR 1.34; 95 % CI 1.16-1.55, p < 0.001). Additionally, female patients were more likely to present with vertebral compression fracture (p < 0.001), while metastatic spinal cord compression (MSCC) and paralysis were more common in male patients (p < 0.001). There was no significant difference in rates of in-hospital complications between female and male patients.

CONCLUSION

Given the significant differences in mortality, disease course, treatment, and in-hospital complications between female and male patients diagnosed with MSD, additional prospective studies are necessary to understand how to meaningfully incorporate these differences into clinical care and prognostication going forward.

Visceral Fat Volume From Standard Preoperative CT is an Independent Predictor of Short-term Survival in Patients Undergoing Surgery for Metastatic Spine Disease

STUDY DESIGN

This is a retrospective cohort.

OBJECTIVE

Determine the relationship of body morphometry to postoperative survival in patients with vertebral metastases.

SUMMARY OF BACKGROUND DATA

Most operations for vertebral metastases aim for palliation not cure, yet expected patient survival heavily influences treatment plans. We seek to demonstrate that preoperative fat and muscle volumes on standard-of-care computed tomography (CT) are independent predictors of survival after surgery for vertebral metastases.

MATERIALS AND METHODS

Included data were preoperative neurological status, adjuvant treatments, CT-assessed body composition, health comorbidities, details of oncologic disease, and Tomita and Tokuhashi scores. Body composition-visceral fat area, subcutaneous fat area, and total muscle area-were assessed on preoperative L3/4 CT slice with Image J software. Multivariable logistic regressions were used to determine independent predictors of 3-, 6-, and 12-month survival.

RESULTS

We included 75 patients (median age, 57, 57.3% male, 66.7% white) with the most common primary lesions being lung (17.3%), prostate (14.7%), colorectal (12.0%), breast (10.7%), and kidney (9.3%). The only independent predictor of 3-month survival was visceral fat area [95% confidence interval (CI): 1.02-1.23 per 1000 mm; P=0.02]. Independent predictors of survival at 6 months were body mass index (95% CI: 1.04-1.35 per kg/m; P=0.009), Karnofsky performance status (95% CI: 1.00-1.15; P<0.05), modified Charlson Comorbidity Index (95% CI: 1.11-7.91; P=0.03), and postoperative chemotherapy use (95% CI: 1.13-4.71; P=0.02). Independent predictors of 12-month survival were kidney primary pathology (95% CI: 0.00-0.00; P<0.01), body mass index (95% CI: 1.03-1.39 per kg/m; P=0.02), and being ambulatory preoperatively (95% CI: 1.28-17.06; P=0.02).

CONCLUSIONS

Visceral fat mass was an independent, positive predictor of short-term postoperative survival in patients treated for vertebral metastases. As a result, we believe that the prognostic accuracy of current predictors may be improved by the addition of visceral fat volume as a risk factor.

Thirty-day complication and readmission rates associated with resection of metastatic spinal tumors: a single institutional experience

Background

This study aims to assess 30-day complication and unplanned readmission rates associated with resection of metastatic spinal tumors.

Methods

Medical records were reviewed for 135 adults who underwent elective resection of a spinal cord tumor. Patient demographics, comorbidities, and tumor characteristics were collected. Tumor pathology was analyzed and diagnosed by a pathologist. The primary outcomes were intra- and 30-day post-operative complication and readmission rates.

Results

Of the 135 spinal tumor resections, 30 (22.2%) cases were metastatic. The most common tumor pathology was bone (13.3%) and the most common locations were thoracic (45.2%), and cervical (32.7%). Most patients had an open surgery (96.7%), with a mean laminectomy/laminoplasty level of 1.9±1.5 and mean operative time of 328.4±658.0 min. There was a 3.3% incidence rate of intraoperative durotomies, with no spinal cord or nerve root injuries. Post-operatively, 44.8% of patients were transferred to the intensive care unit (ICU). The most common post-operative complications were weakness (20.0%), new sensory deficits (16.7%), and hypotension (13.3%). The mean length of stay was 8.8±7.6 days, with the majority of patients discharged home (96.7%). The 30-day readmission rate was 9.7%, with the most common 30-day complications being uncontrolled pain (16.7%), sensory-motor deficits (13.3%), and fever (10.0%).

Conclusions

Our study suggests that weakness, sensory deficits, and uncontrolled pain are the most common complications after resection of spinal metastases, with a relatively high associated 30-day readmission rate. Further studies are necessary to corroborate our findings and identify strategies to reduce complication and readmission rates after resection of spinal metastases.

Phase I/II trial of combined kyphoplasty and intraoperative radiotherapy in spinal metastases

BACKGROUND CONTEXT

Spinal metastases occur in 30%-50% of patients with systemic cancer. The primary goals of palliation are pain control and prevention of local recurrence.

PURPOSE

This study aimed to test the safety and efficacy of a combined modality approach consisting of kyphoplasty and intraoperative radiotherapy (Kypho-IORT).

STUDY DESIGN/SETTING

Kyphoplasty and intraoperative radiotherapy was a prospective, single-center phase I/II trial. Patients were enrolled in a classical 3+3 scheme within the initial phase I, where Kypho-IORT was applied using a needle-shaped 50 kV X-ray source at three radiation dose levels (8 Gy in 8-mm, 8 Gy in 11-mm, and 8 Gy in 13-mm depth). Thereafter, cohort expansion was performed as phase II of the trial. The trial is registered with clinicaltrials.gov, number NCT01280032.

PATIENT SAMPLE

Patients aged 50 years and older with a Karnofsky Performance Status of at least 60% and with one to three painful vertebral metastases confined to the vertebral body were eligible to participate.

OUTCOME MEASURES

The primary end point was safety as per the occurrence of dose-limiting toxicities. The secondary end points were pain reduction, local progression-free survival (L-PFS), and overall survival (OS).

METHODS

Pain was measured using the visual analog scale (VAS) and local control was assessed in serial computed tomography or magnetic resonance imaging scans.

RESULTS

None of the nine patients enrolled in the phase I showed dose-limiting toxicities at any level and thus, 52 patients were subsequently enrolled into a phase II, where Kypho-IORT was performed at various dose levels. The median pain score significantly dropped from 5 preoperatively to 2 at the first postoperative day (p<.001). Of 43 patients who reported a pre-interventional pain level of 3 or more, 30 (69.8%) reported a reduction of ≥3 points on the first postoperative day. A persistent pain reduction beyond the first postoperative day of ≥3 points was seen in 34 (79.1%) patients. The 3, 6, and 12 month L-PFS was excellent with 97.5%, 93.8%, and 93.8%. The 3, 6, and 12 months OS was 76.9%, 64.0%, and 48.4%.

CONCLUSION

Kyphoplasty and intraoperative radiotherapy is safe and immediately provided sustained pain relief with excellent local control rates in patients with painful vertebral metastases.

Metastatic epidural spinal cord compression: does timing of surgery influence the chance of neurological recovery? An observational case-control study

PURPOSE

Metastatic epidural spinal cord compression (MESCC) is radiologically defined as an epidural metastatic lesion causing the displacement of the spinal cord from its normal position in the vertebral canal. The purpose of this paper is the evaluation of the influence of timing of surgery on the chance of neurological recovery.

METHODS

This is a retrospective observational case-control study performed on patients with MESCC from solid tumors surgically treated at our institute from January 2010 to December 2016. Patients included were divided in two groups depending on surgery that was performed within or after 24 h the admission to the hospital. Neurological status was assessed with American Spine Injury Association (ASIA) Impairment Scale.

RESULTS

No statistically significant difference was observed in the variation of ASIA if surgery is performed within or after 24 h from the admission to the hospital. A statistically significant difference was observed after surgery in each group in the improvement of neurological status. A statistically significant difference was reported in the early post-operative complications in patients surgically treated within 24 h.

CONCLUSION

MESCC management is challenge for spine surgeons and may represent an oncologic emergency and if not promptly diagnosed can lead to a permanent neurological damage. According to this study, there is no difference in the chance of neurological recovery if surgery is performed within or after 24 h the admission to hospital, but there is a greater rate of early post-operative complications when surgery is performed within 24 h from the admission to the hospital.

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.

Utility of the Surgical Apgar Score for Patients Who Undergo Surgery for Spinal Metastasis

STUDY DESIGN

Retrospective review of patients who underwent surgery for spinal metastasis between 2005 and 2011.

OBJECTIVE

To assess the utility of the surgical Apgar score (SAS) in patients who underwent surgery for spinal metastasis.

SUMMARY OF BACKGROUND DATA

Surgery for spinal metastasis can be associated with relatively high morbidity and mortality. Consequently, identifying patients at risk for major postoperative complications is important. Several studies have validated SAS for predicting 30-day complication risk.

METHODS

SASs were calculated and patients stratified into 5 groups: scores 0-2, 3-4, 5-6, 7-8, 9-10 points. Multivariate logistic regression assessed whether SAS was an independent predictor of major complication 30 days after surgery. Multivariate analysis of covariance assessed whether SAS was independently associated with length of stay.

RESULTS

Ninety-seven patients with a variety of metastatic tumors were analyzed. There was no obvious trend in complication rates, or significant association between SAS and complication rate (P=0.413). Complication rates were 25.0% for SASs 0-2, 33.3% for 3-4, 18.4% for 5-6, 10.0% for 7-8, and 33.3% for 9-10 points. On multivariate analysis, SAS was not independently associated with complications; age above 65 years (odds ratio 4.19; 95% confidence interval, 1.31-52.27; P=0.028) and preoperative Karnofsky Performance Score of 10-40 (odds ratio 9.13; 95% confidence interval, 1.42-58.63; P=0.020) were associated with higher odds of complication. SASs 0-2 were an independent predictor of longer hospital stay (P=0.004).

CONCLUSIONS

Our findings suggest that SAS is not a significant predictor of major perioperative complications after spinal metastasis surgery; preoperative functional status and age are stronger predictors. The need continues for a preoperative scoring system to reliably predict risk for perioperative complications after spinal metastasis surgery.

Spinal Radiosurgery for Metastatic Disease of the Spine

Background

Metastatic tumor in the spinal column is common, causing symptomatic spinal cord compression in approximately 25,000 patients annually. Although surgical treatment of spinal metastases has become safer, less invasive, and more efficacious in recent years, there remains a subset of patients for whom other treatment modalities are needed. Stereotactic radiosurgery, which has long been used in the treatment of intracranial lesions, has recently been applied to the spine and enables the effective treatment of metastatic lesions.

Methods

We review the evolution of stereotactic radiosurgery and its applications in the spine, including a description of two commercially available systems.

Results

Although a relatively new technique, the use of stereotactic radiosurgery in the spine has advanced rapidly in the past decade. Spinal stereotactic radiosurgery is an effective and safe modality for the treatment of spinal metastatic disease.

Conclusions

Future challenges involve the refinement of noninvasive fiducial tracking systems and the discernment of optimal doses needed to treat various lesions. Additionally, dose-tolerance limits of normal structures need to be further developed. Increased experience will likely make stereotactic radiosurgery of the spine an important treatment modality for a variety of metastatic lesions.

Contemporary spinal oncology treatment paradigms and outcomes for metastatic tumors to the spine: A systematic review of breast, prostate, renal, and lung metastases

Metastatic spinal disease most frequently arises from carcinomas of the breast, lung, prostate, and kidney. Management of spinal metastases (SpM) is controversial in the literature. Recent studies advocate more aggressive surgical resection than older studies which called for radiation therapy alone, challenging previously held beliefs in conservative therapy. A literature search of the PubMed database was performed for spinal oncology outcome studies published in the English language between 2006 and 2016. Data concerning study characteristics, patient demographics, tumor origin and spinal location, treatment paradigm, and median survival were collected. The search retrieved 220 articles, 24 of which were eligible to be included. There were overall 3457 patients. Nine studies of 1723 patients discussed parameters affecting median survival time with comparison of different primary cancers. All studies found that primary cancer significantly predicted survival. Median survival time was highest for primary breast and renal cancers and lowest for prostate and lung cancers, respectively. Multiple spinal metastases, a cervical location of metastasis, and pathologic fracture each had no significant influence on survival. Survival in metastatic spinal tumors is largely driven by primary tumor type, and this should influence palliative management decisions. Surgery has been shown to greatly increase quality of life in patients who can tolerate the procedure, even in those previously treated with radiotherapy. Surgery for SpM can be used as first-line therapy for preservation of function and symptom relief. Future studies of management of SpM are warranted and primary tumor diagnosis should be studied to determine contribution to survival.

Palliative Surgery in Treating Painful Metastases of the Upper Cervical Spine: Case Report and Review of the Literature

Increased incidence of upper cervical metastases and higher life expectancy resulted in higher operative rates in patients. The purpose of this study was to explore the methods and the clinical outcomes of palliative surgery for cervical spinal metastases.A systematic review of a 15-case series of upper cervical metastases treated with palliative surgery was performed. All cases underwent palliative surgery, including anterior tumor resection and internal fixation in 3 cases, posterior tumor resection and internal fixation in 10 cases, and combined anterior and posterior tumor resection and internal fixation in 2 cases. Patients were followed-up clinically and radiologically after the operation, and visual analog scale (VAS) and activities of daily living scores were calculated. In addition, a literature review was performed and patients with upper cervical spine metastases were analyzed.The mean follow-up period was 12.5 months (range, 3-26 months) in this consecutive case series. The pain was substantially relieved in 93.3% (14/15) of the patients after the operation. The VAS and Japanese Orthopedic Association scores showed improved clinical outcomes, from 7.86 ± 1.72 and 11.13 ± 2.19 preoperatively to 2.13 ± 1.40 and 14.26 ± 3.03 postoperatively, respectively. The mean survival time was 9.5 months (range, 5-26 months). Dural tear occurred in 1 patient. Wound infections, instrumentation failure, and postoperative death were not observed. Among our cases and other cases reported in the literature, 72% of the patients were treated with simple anterior or posterior operation, and only 12% of the patients (3/25) underwent complex combined anterior and posterior operation.Metastatic upper cervical spine disease is not a rare occurrence. Balancing the perspective of patients on palliative surgery concerning the clinical benefits of operation versus its operative risks can assist the decision for surgery.

Prognostic factors associated with pain palliation after spine stereotactic body radiation therapy

OBJECT The number of patients with spinal tumors is rapidly increasing; spinal metastases develop in more than 30% of cancer patients during the course of their illness. Such lesions can significantly decrease quality of life, often necessitating treatment. Stereotactic radiosurgery has effectively achieved local control and symptomatic relief for these patients. The authors determined prognostic factors that predicted pain palliation and report overall institutional outcomes after spine stereotactic body radiation therapy (SBRT). METHODS Records of patients who had undergone treatment with SBRT for either primary spinal tumors or spinal metastases from June 2008 through June 2013 were retrospectively reviewed. Data were collected at the initial visit just before treatment and at 1-, 3-, 6-, and 12-month follow-up visits. Collected clinical data included Karnofsky Performance Scale scores, pain status, presence of neurological deficits, and prior radiation exposure at the level of interest. Radiation treatment plan parameters (dose, fractionation, and target coverage) were recorded. To determine the initial extent of epidural spinal cord compression (ESCC), the authors retrospectively reviewed MR images, assessed spinal instability according to the Bilsky scale, and evaluated lesion progression after treatment. RESULTS The study included 99 patients (mean age 60.4 years). The median survival time was 9.1 months (95% CI 6.9-17.2 months). Significant decreases in the proportion of patients reporting pain were observed at 3 months (p < 0.0001), 6 months (p = 0.0002), and 12 months (p = 0.0019) after treatment. Significant decreases in the number of patients reporting pain were also observed at the last follow-up visit (p = 0.00020) (median follow-up time 6.1 months, range 1.0-56.6 months). Univariate analyses revealed that significant predictors of persistent pain after intervention were initial ESCC grade, stratified by a Bilsky grade of 1c (p = 0.0058); initial American Spinal Injury Association grade of D (p = 0.011); initial Karnofsky Performance Scale score, stratified by a score of 80 (p = 0.002); the presence of multiple treated lesions (p = 0.044); and prior radiation at the site of interest (p < 0.0001). However, when multivariate analyses were performed on all variables with p values less than 0.05, the only predictor of pain at last follow-up visit was a prior history of radiation at the site of interest (p = 0.0038), although initial ESCC grade trended toward significance (p = 0.073). Using pain outcomes at 3 months, at this follow-up time point, pain could be predicted by receipt of radiation above a threshold biologically effective dose of 66.7 Gy. CONCLUSIONS Pain palliation occurs as early as 3 months after treatment; significant differences in pain reporting are also observed at 6 and 12 months. Pain palliation is limited for patients with spinal tumors with epidural extension that deforms the cord and for patients who have previously received radiation to the same site. Further investigation into the optimal dose and fractionation schedule are needed, but improved outcomes were observed in patients who received radiation at a biologically effective dose (with an a/b of 3.0) of 66.7 Gy or higher.

ICAM1 depletion reduces spinal metastasis formation in vivo and improves neurological outcome

INTRODUCTION

Clinical treatment of spinal metastasis is gaining in complexity while the underlying biology remains unknown. Insufficient biological understanding is due to a lack of suitable experimental animal models. Intercellular adhesion molecule-1 (ICAM1) has been implicated in metastasis formation. Its role in spinal metastasis remains unclear. It was the aim to generate a reliable spinal metastasis model in mice and to investigate metastasis formation under ICAM1 depletion.

MATERIAL AND METHODS

B16 melanoma cells were infected with a lentivirus containing firefly luciferase (B16-luc). Stable cell clones (B16-luc) were injected retrogradely into the distal aortic arch. Spinal metastasis formation was monitored using in vivo bioluminescence imaging/MRI. Neurological deficits were monitored daily. In vivo selected, metastasized tumor cells were isolated (mB16-luc) and reinjected intraarterially. mB16-luc cells were injected intraarterially in ICAM1 KO mice. Metastasis distribution was analyzed using organ-specific fluorescence analysis.

RESULTS

Intraarterial injection of B16-luc and metastatic mB16-luc reliably induced spinal metastasis formation with neurological deficits (B16-luc:26.5, mB16-luc:21 days, p<0.05). In vivo selection increased the metastatic aggressiveness and led to a bone specific homing phenotype. Thus, mB16-luc cells demonstrated higher number (B16-luc: 1.2±0.447, mB16-luc:3.2±1.643) and increased total metastasis volume (B16-luc:2.87±2.453 mm3, mB16-luc:11.19±3.898 mm3, p<0.05) in the spine. ICAM1 depletion leads to a significantly reduced number of spinal metastasis (mB16-luc:1.2±0.84) with improved neurological outcome (29 days). General metastatic burden was significantly reduced under ICAM1 depletion (control: 3.47×10(7)±1.66×10(7); ICAM-1-/-: 5.20×10(4)±4.44×10(4), p<0.05 vs. control)

CONCLUSION

Applying a reliable animal model for spinal metastasis, ICAM1 depletion reduces spinal metastasis formation due to an organ-unspecific reduction of metastasis development.

Minimal access versus open spinal surgery in treating painful spine metastasis: a systematic review

STUDY DESIGN

The study design of this paper is a systematic review of literature published in the recent 10 years.

OBJECTIVE

It is the objective of this paper to compare the clinical efficacy and safety of minimal access (MIS) spinal surgery and open spinal surgery for treating painful spine metastasis.

METHODS

Two research questions below were determined through a consensus among a panel of spine experts. A systematic review of literature on spinal surgery was conducted by searching PubMed with a combination of keywords including "metastatic", "metastasis", "metastases", "spinal", and "spine". Independent reviewers selected the articles for analysis after screening the titles, abstracts, and full texts, then extracted data and graded the quality of each paper according to the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) criteria. Specific clinical questions were as follows: 1. In patients with spine metastatic disease, what is the impact of different surgical approaches (MIS versus open) on pain relief and functional outcome? 2. In patients with metastatic disease, what is the impact of different surgical approaches (MIS versus open) on local recurrence, survive rate, and complication?

RESULTS

A total of 1,076 abstracts were identified using various keywords. 5 prospective (level II) and 12 retrospective articles (level III) were eligible for inclusion, involving a total of 979 cases of spine metastasis. There were 345 cases in 8 studies regarding the clinical evaluation of MIS spinal surgery and 634 cases in 9 studies regarding the clinical evaluation of open spinal surgery for spine metastasis.

CONCLUSION

Both open spinal surgery and MIS seem to achieve the improvement of pain and neurological dysfunction through decompression and stabilization for patients with spine metastasis, but open surgery may involve more major complications with a trend of lower survival rates and higher recurrence rates compared to MIS.

[Diagnostic standards for extradural tumors and metastases of the spinal column]

Because of the heterogeneous clinical and paraclinical symptoms accompanied by the urgent necessity to rapidly find a diagnosis, the differential diagnostic delineation of spinal tumors from back pain related to other reasons is a special challenge in the orthopedic practice. Employing an algorithm based on anamnesis, clinical, radiological and paraclinical examinations, a guideline-related biopsy as well as histological processing of the biopsy material, tumor lesions can usually be classified regarding entity, dignity and extent. Following this a treatment strategy can be defined. Because of the necessity of an interdisciplinary approach the diagnostic algorithm should be planned during a tumor conference and performed in specialized centers.

[Results-adapted operative treatment options for spinal metastases]

The current operative approaches and technical possibilities in the operative treatment of spinal metastases are manifold which enables an individual operative strategy adapted to the patient's condition. Maintaining quality of life is the primary goal in the treatment of these patients. The therapeutic goals, such as pain control, avoidance of neurological deficits and the achievement of spinal stability have to be attained with as little morbidity as possible. From this perspective the available operative techniques ranging from minimally invasive approaches to complex reconstructive surgery will be addressed and discussed in this article.

Independent predictors of survival and the impact of repeat surgery in patients undergoing surgical treatment of spinal metastasis

Object

Surgery for spinal metastasis is considered palliative, and postoperative survival is often less than a year. Recurrence of metastatic lesions is quite common, and it remains unclear whether repeat surgery is effective. In this study, the authors assessed independent predictors for survival at 6 months, 1 year, and 2 years after surgery, and examined whether repeat surgery for recurrence of spinal metastasis influenced survival rates.

Methods

Retrospective review of the electronic medical records was performed to identify a consecutive population of adult patients who underwent surgery for spinal metastasis during the period 2005–2011. Utilizing a Cox proportional hazard regression model, the authors assessed independent predictors and risk factors for survival at 6 months, 1 year, and 2 years after surgery. In addition, the impact of repeat surgery on survival was specifically assessed via multivariable analysis.

Results

A total of 99 patients were included in the final analysis. The overall mean postoperative duration of survival was 9.6 months. In addition to previously identified predictors of survival (preoperative ambulation, Karnofsky Performance Status [KPS], radiotherapy, primary cancer type, presence of extraspinal metastasis, and number of spinal segments with metastasis), pain on presentation and body mass index (BMI) of 25–30 were both independently associated with survival. Patients with recurrence who underwent repeat surgery had longer mean survival times than patients with recurrence who did not undergo repeat surgery (19.6 months vs 12.8 months, respectively). Repeat surgery was also independently associated with higher survival rates on multivariate analysis. Follow-up KPS was significantly higher in patients who underwent repeat surgery as well.

Conclusions

In addition to confirming previously identified predictors of survival following surgery for spinal metastasis, the authors identified BMI and pain on presentation as independent predictors of survival. They also found that repeat surgery may be a viable option in patients with metastatic recurrence and may offer prolonged survival, likely due to improved functionality, mitigating complications associated with immobility.

Spinal metastasis in head and neck cancer

Background

The incidence of head and neck cancer is relatively low in developed countries and highest in South East Asia. Notwithstanding advances in surgery and radiotherapy over the past several decades, the 5-year survival rate for head and neck cancer has stagnated and remains at 50–55%. This is due, in large part, to both regional and distant disease spread, including spinal metastasis. Spinal metastasis from head and neck cancer is rare, has a poor prognosis and can significantly impede end-stage quality of life; normally only palliative care is given.

This study aims to conduct a systematic review of the evidence available on management of spinal metastasis from head and neck cancer and to use such evidence to draw up guiding principles in the management of the distant spread.

Methods

Systematic review of the electronic literature was conducted regarding the management of spinal metastasis of head and neck malignancies.

Results

Due to the exceptional rarity of head and neck cancers metastasizing to the spine, there is a paucity of good randomized controlled trials into the management of spinal metastasis. This review produced only 12 case studies/reports and 2 small retrospective cohort studies that lacked appropriate controls.

Conclusion

Management should aim to improve end-stage quality of life and maintain neurological function. This review has found that radiotherapy +/− medical adjuvant is considered the principle treatment of spinal metastasis of head and neck cancers.

There is an absence of a definitive treatment protocol for head and neck cancer spinal metastasis. Our failure to find and cite high-quality scientific evidence only serves to stress the need for good quality research in this area.

Strategy for bone metastases treatment in patients with impending cord compression or vertebral fractures: a pilot study

Impending spinal cord compression and vertebral fractures are considered contraindications for radionuclide bone pain palliation therapy. However, most of the patients with widespread bone metastases already have weakened vertebral segments that may be broken. Therefore, local field external-beam radiotherapy or percutaneous vertebroplasty (VP) should be considered to improve the patient's quality of life and to institute subsequent appropriate treatment, including radionuclide therapy for bone pain palliation. The objective of this study was to develop a strategy for an effective treatment of bone metastases in patients with widespread bone metastases and intolerable pain, associated with impending cord compression or vertebral fractures. Eleven patients (5 females and 6 males, aged 32-62 years; mean age 53.8 ± 2.7 years) with multiple skeletal metastases from carcinomas of prostate (n = 3), breast (n = 3) and lung (n = 5) were studied. Their mean pain score measured on a visual analogue scale of 10 was found to be 8.64 ± 0.15 (range 8-9) and the mean number of levels with impending cord compression or vertebral fracture was 2.64 ± 0.34 (range 1-4). All patients underwent vertebroplasty and after 3-7 days received Sm-153 ethylene diamine tetra methylene phosphonic acid (EDTMP) therapy. Sm-153 EDTMP was administered according to the recommended standard bone palliation dose of 37 MBq/kg body weight. Whole body (WB) bone scan, computed tomography and magnetic resonance imaging (MRI) were performed before and after treatment in all patients. Pain relief due to stabilization of vertebrae after VP occurred within the first 12 hours (mean 4.8 ± 1.2 hours; range 0.5-12 hours), and the mean pain score was reduced to 4.36 ± 0.39 (range 2-6). Subsequent to Sm-153 EDTMP treatment, further pain relief occurred after 3.91 ± 0.39 days (range 2-6 days) and the pain score decreased to 0.55 ± 0.21 (range 0-2). The responses to treatment were found to be statistically significant (P < 0.0001). Based on the results on this limited patient population, we conclude that spinal stabilization using VP in patients with widespread bone metastases and impending cord compression is an effective way to decrease disability with pain and to facilitate subsequent systemic palliation of painful skeletal metastases by Sm-153 EDTMP therapy.

Surgical treatment of multiple spine metastases from gastrinoma

STUDY DESIGN

 Case report.

CLINICAL QUESTION

 To report successful surgical therapy for spinal cord compression in a patient with spinal metastases from a pancreatic gastrinoma.

METHODS

 A 43-year-old man presented three times within 4 years with cervical and upper thoracic spinal cord compression because of metastatic gastrinoma. He had two previous spine metastases to the lower thoracic and lumbar spine, a T11 compressive lesion which required a T9L1 fusion, and an L4 lesion that was treated with chemotherapy and stereotactic radiation. The compression was relieved each time by surgery.

RESULTS

 The patient underwent three surgeries in 4 years: (1) debulking and removal of the rib head on the left at T3, and debulking of the tumor at T3 with hemilaminectomy and spinal cord decompression with internal fixation from T1-T5 using posterolateral instrumented fusion and allograft; (2) anterior C7 corpectomy with placement of a cage from C7-T1 with both anterior and posterior fusion of C2C7; and (3) T1-T3 laminectomy, T1-T3 exploration of wound, revision of hardware, T1-T3 removal of spinal tumor, and T3 bilateral transpedicular circumferential decompression. The patient is alive and regained the ability to walk 8 years after initial diagnosis, despite the appearance of spinal metastases 1 year after the diagnosis of liver metastases.

CONCLUSION

 Surgery for spinal cord compression in patients with metastatic neuroendocrine tumors can be effective in relieving radicular pain, weakness and numbness, and while not curative can greatly improve quality of life.

Metal-induced artifacts in MRI

OBJECTIVE

The purpose of this article is to review some of the basic principles of imaging and how metal-induced susceptibility artifacts originate in MR images. We will describe common ways to reduce or modify artifacts using readily available imaging techniques, and we will discuss some advanced methods to correct readout-direction and slice-direction artifacts.

CONCLUSION

The presence of metallic implants in MRI can cause substantial image artifacts, including signal loss, failure of fat suppression, geometric distortion, and bright pile-up artifacts. These cause large resonant frequency changes and failure of many MRI mechanisms. Careful parameter and pulse sequence selections can avoid or reduce artifacts, although more advanced imaging methods offer further imaging improvements.

STUDY ON THE APPLICABILITY OF THE MODIFIED TOKUHASHI SCORE IN PATIENTS WITH SURGICALLY TREATED VERTEBRAL METASTASIS

To present the results obtained from surgical treatment of patients with vertebral metastases, comparing them with the modified Tokuhashi score in order to validate the applicability of this score for prognostic predictions and for choosing surgical treatments.

METHODS

This was a retrospective study on 157 patients treated surgically for spinal metastasis in Erastus Gaertner Hospital in Curitiba. The Tokuhashi score was applied retrospectively to all the patients. The patients' actual survival time was compared with the expected survival time using the Tokuhashi score.

RESULTS

There were 82 females and 75 males. The most frequent location of the primary tumor was the breast. The thoracic region was involved in 66.2%, lumbar region in 65.6%, cervical region in 15.9% and sacral region in 12.7%. All the patients underwent surgical treatment. The most frequent indication for treatment was intractable pain (89.2%). There was partial or complete improvement in a majority of the cases (52.2%). Out of 157 cases studied, 86.6% died. The maximum survival time was 13.6 years, the minimum was 3 days and the mean was 13.2 months. The following frequencies of Tokuhashi scores were found among the operated cases: up to 8 points, 111 cases; 9-11 points, 43 cases; and 12-15 points, three cases. The mean survival time in months for all 157 patients according to the Tokuhashi score was: 0-8 points, 15.4 months; 9-11 points, 11.4 months; and 12-15 points, 12 months.

CONCLUSION

Unlike the nonsurgical approach recommended by Tokuhashi for patients with lower scores, this group in our study was sent for surgery, with better results than those of non-operated patients reported by Tokuhashi.

Metastatic paraplegia and functional outcomes: perspectives and limitations for rehabilitation care. Part 2

OBJECTIVE

To identify functional outcomes that could justify the need for a rehabilitation care program for patients with metastatic epidural spinal cord compression (MESCC) and paraplegia.

DATA SOURCES

Publications from 1950 to January 2010 selected from 3 databases.

STUDY SELECTION

Original articles dealing with outcome data for functional status, pain, and bladder dysfunction.

DATA EXTRACTION

Standardized reading grid.

DATA SYNTHESIS

The data are dominated by retrospective studies for even functional-related data, and studies from rehabilitation teams are rare. They report a functional evolution similar to a population with traumatic spinal cord injury for the first 3 months. Patients who were ambulatory before treatment retained their ability to walk, and patients who were nonambulatory before treatment could regain gait abilities. Data also showed a positive impact on pain and bladder and/or bowel dysfunction.

CONCLUSIONS

By restricting physical medicine and rehabilitation therapeutic care to a short time (1-2mo), the progression margin is possible in the short term and implies a voluntary and active therapeutic care approach for patients with paraplegia after MESCC on the basis of a codified and standardized program with clinical indicators, as well as patients' comfort indicators.

Minimally invasive surgery treatment for thoracic spine tumor removal: a mini-open, lateral approach

STUDY DESIGN

Prospective registry.

OBJECTIVE

The objective of this study is to examine procedural and long-term outcomes of a mini-open, lateral approach for tumor removal in the thoracic spine.

SUMMARY OF BACKGROUND DATA

The majority of spinal tumors present as metastatic tumors in the thoracic spine. Conventional surgical treatments have been associated with high rates of approach-related morbidities as well as difficult working windows for complete tumor excision. Recent advances in minimally invasive techniques, particularly mini-open (minimally invasive, not endoscopic) approaches, help to reduce the morbidities of conventional procedures with comparable outcomes.

METHODS

Twenty-one consecutively treated patients at 2 institutions were treated between 2007 and 2009. Treatment variables, including operating time, estimated blood loss, length of hospital stay, and complications were collected, as were outcome measures, including the visual analog scale for pain and the Oswestry disability index.

RESULTS

Twenty-one patients with thoracic spinal tumors were successfully treated with a minimally invasive lateral approach. Operating time, estimated blood loss, and length of hospital stay were 117 minutes, 291 mL, and 2.9 days, respectively. One (4.8%) perioperative complication occurred (pneumonia). Mean follow-up was 21 months. Two patients had residual tumor at last follow-up. Two patients died during the study as the result of other metastases (spine tumor was secondary). Visual analog scale improved from 7.7 to 2.9 and Oswestry disability index improved from 52.7% to 24.9% from preoperative to the last follow-up.

CONCLUSION

The mini-open lateral approach described here can be performed safely and without many of the morbidities and difficulties associated with conventional and endoscopic procedures. Proper training in minimally invasive techniques and the use of direct-visualization minimally invasive retractors are required to safely and reproducibly treat these complex indications.

Efficacy evaluation of a new treatment algorithm for spinal metastases

STUDY DESIGN

A semiprospective clinical study was conducted.

OBJECTIVE

To evaluate the efficacy of a new treatment algorithm for spinal metastases.

SUMMARY OF BACKGROUND DATA

The surgical treatments in spinal metastatic have been progressing in recent years, while the surgical indications have been controversial. A new treatment algorithm for spinal metastases was developed and prospectively applied clinically in our department since 2002.

METHODS

This study included 202 patients with 206 lesions treated in January 1997 to December 2006 and continuously followed-up for more than 6 months or dead within this period. A total of 124 patients with 124 lesions were operated before 2002 were allocated to the control group and 78 patients with 82 lesions prospectively treated after 2002 were allocated to the prospective study group. The primary managements were nonsurgical treatment, palliative surgery, debulking, and en bloc resection. Neurologic evolvement, postoperative survival time, and local recurrence/development rates were statistically compared as the indexes of treatment outcome.

RESULTS

Although there was no significant difference of neurologic evolvement immediately after operation (P = 0.24), the prospective study group achieved significantly better neurologic function than the control group long time after operation (P = 0.03). No significant difference (P = 0.26) was shown in local recurrence/development rate comparison. The mean postoperative survival time comparison showed significant difference (P < 0.01).

CONCLUSION

The efficacy of the algorithm has been validated preliminarily by the significantly longer survival time and better long-time neurologic function evolvement in the prospectively study group. But the algorithm should continuously be in development and be updated with the latest improvement in metastatic treatment.

Outcome of excisional surgeries for the patients with spinal metastases

To evaluate the outcome of the excisional surgeries (en bloc/debulking) in spinal metastatic treatment in 10 years. A total of 131 patients (134 lesions) with spinal metastases were studied. The postoperative survival time and the local recurrence rate were calculated statistically. The comparison of the two procedures on the survival time, local recurrence rate, and neurologic change were made. The median survival time of the en bloc surgery and the debulking surgery was 40.93 and 24.73 months, respectively, with no significant difference. The significant difference was shown in the local recurrence rate comparison, but not in neurological change comparison. 19.85% patients combined with surgical complications. The en bloc surgery can achieve a lower local recurrence rate than the debulking surgery, while was similar in survival outcome, neurological salvage, and incidence of complications. The risk of the excisional surgeries is high, however, good outcomes could be expected.

Phase I trial of vertebral intracavitary cement and samarium (VICS): novel technique for treatment of painful vertebral metastasis

PURPOSE

Kyphoplasty is an effective procedure to alleviate pain in vertebral metastases. However, it has no proven anticancer activity. Samarium-153-ethylene diamine tetramethylene phosphonate ((153)Sm-EDTMP) is used for palliative treatment of bone metastases. A standard dose of 1 mCi/kg is administrated intravenously. The present study was conducted to determine the feasibility of intravertebral administration of (153)Sm with kyphoplasty.

METHODS AND MATERIALS

A total of 33 procedures were performed in 26 patients. Of these 26 patients, 7 underwent procedures performed at two vertebral levels. The mean age of the cohort was 64 years (range, 33-86). The kyphoplasty procedure was performed using a known protocol; 1-4 mCi of (153)Sm was admixed with the bone cement and administered under tight radiation safety measures. Serial nuclear body scans were obtained. Pain assessment was evaluated using a visual analog pain score.

RESULTS

All patients tolerated the procedure well. No procedure-related morbidities were noted. No significant change had occurred in the blood counts at 1 month after the procedure. One case was not technically satisfactory. Nuclear scans revealed clear radiotracer uptake in the other 32 vertebrae injected. Except for the first patient, no radiation leakage was encountered. The mean pain score using the visual analog scale improved from 8.6 before to 2.8 after the procedure (p < .0001). Follow-up bone scans demonstrated a 43% decrease in the tracer uptake.

CONCLUSION

The results of our study have shown that the combination of intravertebral administration of (153)Sm and kyphoplasty is well tolerated with adequate pain control. No hematologic adverse effects were found. A reduction of the bone scan tracer uptake was observed in the injected vertebrae. Longer follow-up is needed to study the antineoplastic effect of the procedure.

Percutaneous tumor curettage and interstitial delivery of samarium-153 coupled with kyphoplasty for treatment of vertebral metastases

Object

The object of this study was to investigate the use of a minimally invasive technique for treating metastatic tumors of the vertebral body, aimed at relieving pain, preventing further tumor growth, and minimizing the adverse effects of systemic use of samarium-153 (153Sm).

Methods

The procedure is performed in the same fashion as a kyphoplasty, using a unilateral extrapedicular approach under local anesthesia/mild general sedation, with the patient in the lateral decubitus position. The tumor is accessed as in a standard kyphoplasty. The side is chosen according to the location of the metastasis. Prior to inflation of the balloon the tumor is debulked by percutaneous curettage. Balloon inflation is carried out as per standard kyphoplasty in an attempt to create a larger space and reduce a possible kyphotic deformity. Three mCi of 153Sm-EDTMP (ethylenediaminetetramethylenephosphonic acid) is then mixed with bone cement (polymethylmethacrylate) and injected into the void created by the balloon tamp.

Results

Twenty-four procedures were performed in 19 patients. There was reliable and reproducible delivery of the radiolabeled 153Sm-EDTMP to the metastatic site, without spillage. The procedure was safe. There were no procedure-related complications. There was no hematological toxicity with the low doses of 153Sm used. Pain improved in all patients. The long-term results related to tumor control continue to be investigated.

Conclusions

Combined percutaneous debulking of confined vertebral metastases and administration of local 153Sm is feasible and safe. Furthermore, this technique leads to immediate relief of cancer-related pain and may help prevent or slow down the progression of vertebral metastatic tumors.

Selecting treatment for patients with malignant epidural spinal cord compression-does age matter?: results from a randomized clinical trial

STUDY DESIGN

Randomized clinical trial. OBJECTIVE.: To determine if age affects outcomes from differing treatments in patients with spinal metastases.

SUMMARY OF BACKGROUND DATA

Recently, class I data were published supporting surgery with radiation over radiation alone for patients with malignant epidural spinal cord compression (MESCC). However, the criteria to properly select candidates for surgery remains controversial and few independent variables which predict success after treatment have been identified.

METHODS

Data for this study was obtained in a randomized clinical trial comparing surgery versus radiation for MESCC. Hazard ratios were determined for the effect of age and the interaction between age and treatment. Age estimates at which prespecified relative risks could be expected were calculated with greater than 95% confidence to suggest possible age cut points for further stratification. Multivariate models and Kaplan-Meier curves were tested using stratified cohorts for both treatment groups in the randomized trial each divided into 2 age groups.

RESULTS

Secondary data analysis with age stratification demonstrated a strong interaction between age and treatment (hazard ratio = 1.61, P = 0.01), such that as age increases, the chances of surgery being equal to radiation alone increases. The best estimate for the age at which surgery is no longer superior to radiation alone was calculated to be between 60 and 70 years of age (95% CI), using sequential prespecified relative risk ratios. Multivariate modeling and Kaplan-Meier curves for stratified treatment groups showed that there was no difference in outcome between treatments for patients >or=65 years of age. Ambulation preservation was significantly prolonged in patients <65 years of age undergoing surgery compared to radiation alone (P = 0.002).

CONCLUSION

Age is an important variable in predicting preservation of ambulation and survival for patients being treated for spinal metastases. Our results provide compelling evidence for the first time that particular age cut points may help in selecting patients for surgical or nonsurgical intervention based on outcome.

Does spinal surgery improve the quality of life for those with extradural (spinal) osseous metastases? An international multicenter prospective observational study of 223 patients. Invited submission from the Joint Section Meeting on Disorders of the Spine and Peripheral Nerves, March 2007

OBJECT

Opinions vary widely as to the role of surgery (from none to wide margin excision) in the management of spinal metastases. In this study the authors set out to ascertain if surgery improves the quality of remaining life in patients with spinal metastatic and tumor-related systemic disease.

METHODS

The authors included 223 patients in this study who were referred by oncologists and physicians over a 2-year period. All underwent surgery. Surgery was classified according to extent of excision ranging from en bloc excision or debulking to palliative surgery. All patients had a histologically confirmed diagnosis of epithelial spinal metastasis, and an oncology specialist undertook appropriately indicated adjuvant therapy in almost half of the patients.

RESULTS

The mean patient age was 61 years. Excisional en bloc or debulking surgery was performed in 74%; the rest had (minimal) palliative decompression. All patients considered for surgery were included in the study. Patients presented with pain in 92% of cases, paraparesis in 24%, and abnormal urinary sphincter function in 22% (5% were incontinent). Breast, renal, lung, and prostate accounted for 65% of the cancers, and in 60% of patients there were widespread spinal metastases (Tomita Type 6 or 7). The incidence of perioperative death (within 30 days of surgery) was 5.8%. Postoperatively 71% of the entire group had improved pain control, 53% regained or maintained their independent mobility, and 39% regained urinary sphincter function. The median survival for the cohort was 352 days (11.7 months); those who underwent excision survived significantly longer than those in the palliative group (p = 0.003). As with survival results, functional improvement outcome was better in those who underwent excision.

CONCLUSIONS

Surgical treatment was effective in improving quality of life by providing better pain control, enabling patients to regain or maintain mobility, and offering improved sphincter control. Although not a treatment of the systemic cancer, surgery is feasible, has acceptably low mortality and morbidity rates, and for many will improve the quality of their remaining life.

En bloc spondylectomy reconstructions in a biomechanical in-vitro study

Wide surgical margins make en bloc spondylectomy and stabilization a referred treatment for certain tumoral lesions. With a total resection of a vertebra, the removal of the segment's stabilizing structures is complete and the instrumentation guidelines derived from a thoracolumbar corpectomy may not apply. The influence of one or two adjacent segment instrumentation, adjunct anterior plate stabilization and vertebral body replacement (VBR) designs on post-implantational stability was investigated in an in-vitro en bloc spondylectomy model. Biomechanical in-vitro testing was performed in a six degrees of freedom spine simulator using six human thoracolumbar spinal specimens with an age at death of 64 (+/- 20) years. Following en bloc spondylectomy eight stabilization techniques were performed using long and short posterior instrumentation, two VBR systems [(1) an expandable titanium cage; (2) a connected long carbon fiber reinforced composite VBR pedicle screw system)] and an adjunct anterior plate. Test-sequences were loaded with pure moments (+/- 7.5 Nm) in the three planes of motion. Intersegmental motion was measured between Th12 and L2, using an ultrasound based analysis system. In flexion/extension, long posterior fixations showed significantly less range of motion (ROM) than the short posterior fixations. In axial rotation and extension, the ROM of short posterior fixation was equivalent or higher when compared to the intact state. There were only small, nonsignificant ROM differences between the long carbon fiber VBR and the expandable system. Antero-lateral plating stabilized short posterior fixations, but did not markedly effect long construct stability. Following thoracolumbar en bloc spondylectomy, it is the posterior fixation of more than one adjacent segment that determines stability. In contrast, short posterior fixation does not sufficiently restore stability, even with an antero-lateral plate. Expandable verses nonexpandable VBR system design does not markedly affect stability.

Chirurgisches Management von Wirbelsäulenmetastasen

The spine is the most frequent site of skeletal metastases. Among all spinal malignancies metastatic disease is most frequent and indicative of disseminating tumor disease. Depending on primary tumor entity, estimated survival time, general health status of the patient, presence of spinal instability and neurological deficits an oncological useful and patient-specific therapeutic intervention should be performed. New anterior approaches, resections and reconstruction techniques are making surgery a preferred method over radiation therapy. For differential indication of the multiple surgical treatment modalities prognostic scores are available to assist individual decision making. Indications for surgery include survival prognosis of minimum 3 months, intractable pain, progress of myelon compression and/or neurological deficits under radiochemotherapy, spinal instability and necessity for histological diagnosis. Resulting quality of life depends on efficient decompression of the spinal cord and restoration of spinal stability. To achieve these ultimate goals there are different anterior and posterior approaches, instrumentations and vertebral body replacement implants available. Preoperative embolization should be performed in hypervascular tumors, e.g., renal cell cancer. Vertebro-/Kyphoplasty as a percutaneous intervention should be considered for painful multisegmental disease and symptomatic osteolysis without epidural tumor compression to reach analgesia and stability. A multidisciplinary approach in patient selection, decision making and management is an essential precondition for complication avoidance and acceptable quality of life.

Cost-effectiveness of surgery plus radiotherapy versus radiotherapy alone for metastatic epidural spinal cord compression

PURPOSE

A recent randomized clinical trial has demonstrated that direct decompressive surgery plus radiotherapy was superior to radiotherapy alone for the treatment of metastatic epidural spinal cord compression. The current study compared the cost-effectiveness of the two approaches.

METHODS AND MATERIALS

In the original clinical trial, clinical effectiveness was measured by ambulation and survival time until death. In this study, an incremental cost-effectiveness analysis was performed from a societal perspective. Costs related to treatment and posttreatment care were estimated and extended to the lifetime of the cohort. Weibull regression was applied to extrapolate outcomes in the presence of censored clinical effectiveness data.

RESULTS

From a societal perspective, the baseline incremental cost-effectiveness ratio (ICER) was found to be $60 per additional day of ambulation (all costs in 2003 Canadian dollars). Using probabilistic sensitivity analysis, 50% of all generated ICERs were lower than $57, and 95% were lower than $242 per additional day of ambulation. This analysis had a 95% CI of -$72.74 to 309.44, meaning that this intervention ranged from a financial savings of $72.74 to a cost of $309.44 per additional day of ambulation. Using survival as the measure of effectiveness resulted in an ICER of $30,940 per life-year gained.

CONCLUSIONS

We found strong evidence that treatment of metastatic epidural spinal cord compression with surgery in addition to radiotherapy is cost-effective both in terms of cost per additional day of ambulation, and cost per life-year gained.

Minimally Invasive Approaches to Vertebral Column and Spinal Cord Tumors

Minimally invasive approaches to spinal tumors have evolved rapidly over the past 15 to 20 years as clinicians seek to avoid the morbidity and long-term dysfunction associated with traditional open surgical procedures. We review the noninvasive, percutaneous, and minimally invasive surgical techniques currently available for the treatment of spinal column and intradural spinal tumors, including minimal access thoracic corpectomy and minimal access intradural tumor surgery. The various advantages and limitations of these approaches as well as their appropriate indications and uses are also presented here. A measured understanding of surgical objectives and iatrogenic effects on patients' quality of life allows the surgeon to implement such minimally invasive approaches in the design of individualized treatment plans that range from pure palliation to definitive cure.