Metastatic disease of the spine

Diagnosis and Management of Thoracic Myelopathy

Thoracic myelopathy can be a challenging condition to diagnose and treat. Successful outcomes depend on early recondition of the pathology and appropriate surgical referral in cases of progressive neurologic deterioration. The thoracic cord is tethered in kyphosis by the dentate ligaments and contains a tenuous blood supply. These conditions make the thoracic cord particularly susceptible to external compression and ischemic damage. Careful preoperative planning with specific attention to the location and source of thoracic stenosis is critical to successful decompression and complication avoidance. The purpose of this discussion is to outline the common sources of thoracic myelopathy and current recommendations regarding diagnosis and management. The review concludes with an overview of the most up-to-date literature regarding clinical outcomes.

Basal Cell Carcinoma With Metastasis to the Thoracic Spine: An Uncommon Case Report and Review of the Literature

Basal cell carcinoma is an exceedingly rare cause of spinal metastatic disease for which the treatment algorithm is poorly defined. We present a positive patient outcome after treatment of T8 metastatic basal with posterior decompression and fusion followed by later anterior reconstruction, in addition to targeted radiation therapy and pharmacologic therapy. In general, a personalized and comprehensive treatment approach should be used, incorporating surgical, oncologic, and pharmacologic methods as able. Moreover, primary preventive medical and mental health care can help prevent delayed presentation and increased access to timely care.

Translation and Cross-cultural Adaptation of the SOSG-OQ 2.0 Questionnaire into Brazilian Portuguese

Objective:  To perform the cross-cultural adaptation and translation into Brazilian Portuguese of the Spine Oncology Study Group - Outcomes Questionnaire 2.0 (SOSG-OQ 2.0) to enable its application to Brazilian patients and to allow Brazilian researchers to use a questionnaire that is on trend in the scientific literature. Materials and Methods:  The present is a basic, non-randomized, non-comparative study. The translation followed the proposal by Reichenheime and Moraes, mainly for the semantic equivalence and measurement equivalence sessions, as well as the recommendations by Coster and Mancini mainly in the translation stage. The stages were as follows: first - translation into Brazilian Portuguese; second - back-translation; third - semantic comparison; fourth - validation of the final construct. Results:  The translations of the SOSG-OQ 2.0 made by three translators presented a high degree of similarity for most questions. The translators kept all question titles and subtitles, as well as their internal and external orders. Two sworn translators, with native proficiency in English, performed the back-translation of the amalgamated text. Both back-translations were quite similar, and any differences were solved through consensus between the main author and the sworn translators, and the translated text was considered the final version. Conclusion:  The present study shows a translated version of the SOSG-OQ 2.0 with semantic validity with the original version published in English. As such, researchers can apply the questionnaire to the Brazilian population, adding another tool for spine surgeons to improve the monitoring of this complex group of patients.

Treatment strategy for vertebral metastases from anal squamous cell carcinoma: a comprehensive literature review and case report

Purpose/aim of the study: Purpose/aim of the study:Central nervous system (CNS), skull, and vertebral metastases from anal squamous cell carcinoma (SCC) are an exceedingly rare entity. We report the first case of multiple vertebral metastases from a primary anal SCC with the aim of define a target therapeutic strategy.Case presentation: We present the case of a 68-year-old male admitted to our hospital for acute exacerbation chronic low back pain and left L2 radiculopathy. His medical history included the diagnosis of a human papilloma virus related, moderately differentiated anal SCC (cT3N0M0-stage IIB), treated with standard chemoradiotherapy regimen two years earlier. Spinal magnetic resonance imaging revealed an isolated solid lesion of the L2 vertebral body. After the surgical removal, histopathological examination confirmed the diagnosis of moderately differentiated SCC. At 1-month radiological follow-up, two new lesions at the level of T7 to T11 were identified. Additional chemotherapy and radiotherapy for metastatic localization of L2, T7, and T11 were administered. Two-year follow-up demonstrated a radiologically and clinically well-controlled disease. To supplement our case, a systematic literature review on the CNS, skull, and vertebral metastases and their treatments has been performed.Conclusion: Despite several proposed guidelines for the management of vertebral metastases, at present, a universally accepted treatment strategy for vertebral metastases from anal SCC has not been defined. Based on our clinical experience and literature review, in case of vertebral metastases from anal SCC, a prompt and aggressive, local and systemic, and multimodal treatment of the vertebral lesions may be paramount to improve the patient outcomes.

Sociodemographic Characteristics of Patients Undergoing Surgery for Metastatic Disease of the Spine

INTRODUCTION

Some patients, particularly those who are socioeconomically deprived, are diagnosed with primary and/or metastatic cancer only after presenting to the emergency department. Our objective was to determine sociodemographic characteristics of patients undergoing surgery for metastatic spine disease at our institution.

METHODS

This retrospective case series included patients 18 years and older who presented to the emergency department with metastatic spine disease requiring surgery. Demographics and survival data were collected. Sociodemographic characteristics were estimated using the Social Deprivation Index (SDI) and Area Deprivation Index (ADI) for the state of California. Univariate log-rank tests and Kaplan-Meier curves were used to assess differences in survival for predictors of interest.

RESULTS

Between 2015 and 2021, 64 patients underwent surgery for metastatic disease of the spine. The mean age was 61.0 ± 12.5 years, with 60.9% being male (n = 39). In this cohort, 89.1% of patients were non-Hispanic (n = 57), 71.9% were White (n = 46), and 62.5% were insured by Medicare/Medicaid (n = 40). The mean SDI and ADI were 61.5 ± 28.0 and 7.7 ± 2.2, respectively. 28.1% of patients (n = 18) were diagnosed with primary cancer for the first time while 39.1% of patients (n = 25) were diagnosed with metastatic cancer for the first time. During index hospitalization, 37.5% of patients (n = 24) received palliative care consult. The 3-month, 6-month, and all-time mortality rates were 26.7% (n = 17), 39.5% (n = 23), and 50% (n = 32), respectively, with 10.9% of patients (n = 7) dying during their admission. Payor plan was significant at 3 months ( P = 0.02), and palliative consultation was significant at 3 months ( P = 0.007) and 6 months ( P = 0.03). No notable association was observed with SDI and ADI in quantiles or as continuous variables.

DISCUSSION

In this study, 28.1% of patients were diagnosed with cancer for the first time. Three-month and 6-month mortality rates for patients undergoing surgery were 26.7% and 39.5%, respectively. Furthermore, mortality was markedly associated with palliative care consultation and insurance status, but not with SDI and ADI.

LEVEL OF EVIDENCE

Retrospective case series, Level III evidence.

Posterior Endoscopic Cervical Decompression in Metastatic Cervical Spine Tumors: An Alternative to Palliative Surgery

Metastatic spinal cord compression of the cervical spine is a well-known consequence of cancer that generally manifests as an oncological emergency. This study presents and describes an alternative to the minimally invasive posterior full-endoscopic approach for direct decompression and tumor debulking from the metastasis of hepatocellular carcinoma (HCC) in the cervical spine. A 54-year-old man presented with progressive cervical radiculopathy that had persisted for 3 months. The underlying disease was HCC. Radiographic examination revealed evidence of metastatic spinal cord compression with an epidural mass at the C4-C5 levels, which compressed the C4-C5 spinal cord without bony destruction. The modified Tomita score was 6 to 8 points based on palliative surgery. A posterior full-endoscopic approach to remove the tumor from the metastasis of HCC in the cervical spine was done. A postoperative radiographic study revealed adequate tumor mass resection and spinal decompression. The patient was extremely satisfied with this alternative treatment and achieved complete neurologic recovery at 1 month and no recurrent symptoms at the 6-month follow-up. The technique of posterior full-endoscopic decompression of cervical metastasis causing unilateral radiculopathy, presented in this study, is feasible. This surgical intervention seems to be optional minimally invasive and acts as an alternative to palliative surgery.

Utility of dual energy computed tomography in the evaluation of infiltrative skeletal lesions and metastasis: a literature review

Computed tomography (CT) is routinely used to diagnose and evaluate metastatic lesions in oncology. CT alone suffers from lack of sensitivity, especially for skeletal lesions in the bone marrow and lesions that have similar attenuation profiles to surrounding bone. Magnetic resonance imaging and nuclear medicine imaging remain the gold standard in evaluating skeletal lesions. However, compared to CT, these modalities are not as widely available or suitable for all patients. Dual energy computed tomography (DECT) exploits variations in linear attenuation coefficient of materials at different photon energy levels to reconstruct images based on material composition. DECT in musculoskeletal imaging is used in the imaging of crystal arthropathy and detecting subtle fractures, but it is not broadly utilized in evaluating infiltrative skeletal lesions. Malignant skeletal lesions have different tissue and molecular compositions compared to normal bone. DECT may exploit these physical differences to delineate infiltrative skeletal lesions from surrounding bone better than conventional monoenergetic CT. Studies so far have examined the utility of DECT in evaluating skeletal metastases, multiple myeloma lesions, pathologic fractures, and performing image-guided biopsies with promising results. These studies were mostly retrospective analyses and case reports containing small samples sizes. As DECT becomes more widely used clinically and more scientific studies evaluating the performance of DECT are published, DECT may eventually become an important modality in the work-up of infiltrative skeletal lesions. It may even challenge MRI and nuclear medicine because of relatively faster scanning times and ease of access.

Intradural Extramedullary Metastasis from Primary Carcinoma of Breast via Brachial Plexus Perineural Spread: A Case Report and Review of Literature

Intradural extramedullary metastasis from breast carcinoma is a rare occurrence. Furthermore, patients with primary breast carcinoma presenting with neurological symptoms in the first place are even rarer, which was the case in our patient. A 60-year-old woman presented with left upper limb monoparesis for 2 years and rapidly progressive weakness in the left lower limb for 1 week. The patient was evaluated and investigated to find primary left breast carcinoma with metastasis to multiple sites including C5-T1 intradural extramedullary spread. The patient was treated surgically, and decompression and tissue diagnosis were achieved to form a base for starting adjuvant therapy and safeguarding further neurological deterioration due to cord compression. In advanced metastatic cancer, preservation of neurologic function is the goal of surgical treatment. Thorough evaluation of patients presenting with a neurological deficit is always mandatory. Patient education is equally important for palliative treatment as well as to help reduce the burden of metastatic diseases.

Hardware Failure in Spinal Tumor Surgery: A Hallmark of Longer Survival?

Objective: Instrumentation failure in spine tumor surgery is a common reason for revision operation. Increases in patient survival demand a better understanding of the hardware longevity. The study objective was to investigate risk factors for instrumentation failure requiring revision surgery in patients with spinal tumors.Methods: A retrospective cohort from a single tertiary care specialty hospital from January 2005 to January 2021, for patients with spinal primary or metastatic tumors who underwent surgical intervention with instrumentation. Demographic and treatment data were collected and analyzed. Kaplan-Meier analysis was performed for overall survival, and separate univariate and multivariate regression analysis was performed.Results: Three hundred fifty-one patients underwent surgical intervention for spinal tumor, of which 23 experienced instrumentation failure requiring revision surgery (6.6%). Multivariate regression analysis identified pelvic fixation (odds ratio [OR], 10.9), spinal metastasis invasiveness index (OR, 1.11), and survival of greater than 5 years (OR, 3.6) as significant risk factors for hardware failure. One- and 5-year survival rates were 57% and 8%, respectively.Conclusion: Instrumentation failure after spinal tumor surgery is a common reason for revision surgery. Our study suggests that the use of pelvic fixation, invasiveness of the surgery, and survival greater than 5 years are independent risk factors for instrumentation failure.

Treatment Strategy for Metastatic Spinal Tumors: A Narrative Review

Metastatic spinal tumors are common, and their rising incidence can be attributed to the expanding aging population and increased survival rates among cancer patients. The decision-making process in the treatment of spinal metastasis requires a multidisciplinary approach that includes medical and radiation oncology, surgery, and rehabilitation. Various decision-making systems have been proposed in the literature in order to estimate survival and suggest appropriate treatment options for patients experiencing spinal metastasis. However, recent advances in treatment modalities for spinal metastasis, such as stereotactic radiosurgery and minimally invasive surgical techniques, have reshaped clinical practices concerning patients with spinal metastasis, making a demand for further improvements on current decision-making systems. In this review, recent improvements in treatment modalities and the evolution of decision-making systems for metastatic spinal tumors are discussed.

Initial Report of an Intradural Extramedullary Metastasis of a Pancreatic Neuroendocrine Tumor to the Cervical Spine: A Case Report and Review of the Literature

BACKGROUND

Pancreatic neuroendocrine tumors (pNETs) are known to frequently metastasize to the liver and lymphatics; however, metastasis to the spine is exceedingly rare. We report the first case of an intradural, extramedullary pNET metastasis to the upper cervical spine.

CASE DESCRIPTION

A 75-year-old Hispanic male patient with history of stage IV pNET with metastasis to the liver and lymph nodes and new-onset lymphadenopathy seen on CT of the chest was found on positron emission tomography scan to have a lesion in the cervical spine. The patient was neurologically intact on physical examination, yet given the patient's medical history, magnetic resonance imaging of the cervical spine was performed, revealing a right-sided intradural, extramedullary mass at the C1-C2 level with associated mass effect on the spinal cord, likely representing a schwannoma. Due to the tumor size, mass effect, and the need for definitive tissue diagnosis, a partial C1-C2 laminectomy with intradural resection of the tumor was performed. The histology was consistent with the patient's known pNET.

CONCLUSIONS

As treatment for pNETs has evolved, there has been a surge in unique presentations of systemic well-differentiated pNETs being reported. It is vital that patients diagnosed with pNET be monitored for metastases, and when discovered, treated promptly.

Sarcopenia, but not frailty, predicts early mortality and adverse events after emergent surgery for metastatic disease of the spine

BACKGROUND CONTEXT

Frailty and sarcopenia variably predict adverse events (AEs) in a number of surgical populations.

PURPOSE

The aim of this study was to investigate the ability of frailty and sarcopenia to independently predict early mortality and AEs following urgent surgery for metastatic disease of the spine.

STUDY DESIGN

A single institution, retrospective cohort study.

PATIENT SAMPLE

One hundred eight patients undergoing urgent surgery for spinal metastases from 2009 to 2015.

OUTCOME MEASURES

The incidence of AEs including 1- and 3-month mortality.

METHODS

Sarcopenia was defined using the L3 Total Psoas Area/Vertebral body Area (L3-TPA/VB) technique on CT. The modified Frailty Index (mFI), Metastatic Frailty Index (MSTFI) and the Bollen prognostic scales were calculated for each patient. Additional data included demographics, tumor type and burden, neurological status, the extent of surgical treatment and the use of radiation-therapy. Spearman correlation test, logistic regression and Kaplan-Meier were used to study the relation between the outcomes measures and potential predictors (L3-TPA/VB, MSTFI, mFI, and the Bollen prognostic scales).

RESULTS

Eighty-five percent of patients had at least one acute AE. Sarcopenia predicted the occurrence of at least one postop AE (L3-TPA/VB, 1.07±0.40 vs. 1.25±0.52; p=.031). Sarcopenia (L3-TPA/VB) and the degree of neurological impairment were predictive of postoperative AE but MFI or MSTFI were not. Sarcopenia predicted 3-month mortality, independent of primary tumor type (L3-TPA/VB: 0.86±0.27 vs. 1.12±0.41; p<.001). Kaplan-Meyer analysis showed L3-TPA/VB and the Bollen Scale to significantly discriminate patient survival.

CONCLUSIONS

Sarcopenia, easily measured by the L3-TPA/VB on conventional CT, predicts both early postoperative mortality and adverse events in patients undergoing urgent surgery for spinal metastasis, thus providing a practical tool for timely therapeutic decision-making in this complex patient population.

Approaching spinal metastases spread profile

BACKGROUND

Spinal metastases cause significant morbidity. The vertebral column is the most common site of cancer metastasis, however predilection of metastases for the spine is not fully understood.

OBJECTIVE

The aim of the present investigation was to obtain a better description of the distribution of spinal metastases. The main objective of our study was to figure out how malignant cells disseminate within the spine and determine a potent mapping or profile of the metastatic spread routes.

STUDY DESIGN

A prospective French national multicenter database.

METHODS

740 consecutive patients were treated for spine metastasis (SpM) between January 2014 and 2017. A categorisation of the anatomical distribution of spine lesions was conducted.

RESULTS

One hundred and seventy patients (22.9% of series) presented cervical SpM, 440 (60%) lumbar SpM, and a majority 530 (71.6%) at the thoracic vertebral level. Metastases were more often present in the vertebral body (645 patients, 87.2%) than in a posterior location (278 patients, 37.6%, p < 0.0001). 212/740 patients (28.6%) presented circumferential spine involvement (body and posterior elements). An associated epiduritis was presented in 404 patients (54.6%). Primitive neck tumors spread towards the cervical spine: ENT (34.8%, p = 0.049), thyroid (33.3%, p = 0.043) whereas pelvic tumors targeted the lumbar spine: prostate (72%, p = 0.011), bladder (75%, p = 0.047). All tumors presented a tropism for thoracic vertebrae. Significant tumor/vertebrae associations were identified: lung (p = 0.004) and thyroid (p = 0.028) for L₁, bladder for L₅ (p = 0.0025), breast for C₆ (p = 0.006), Prostate for L₁-L₄ (p = 0.002-0.04), multiple myelomas for C₇, p = 0.03, T₃-T₇ (p < 0.0001-0.025) and L₁-L₄ (p = 0.004-0.027). Spine was the latest organ affected by metastases with a median-free survival of 4.2 months (SD 1.8, p = 0.001).

CONCLUSIONS

Although we determined that some tumors have a significant propensity to localise at certain vertebral level, it remains premature to conclude on a spinal metastases profile. To date, it is too early to provide recommendations in imaging follow-up or in preventive therapeutic based on this mapping of spine metastases.

Update on Preoperative Embolization of Bone Metastases

Management of patients with bone metastasis is complex and should include different specialties. Goals of therapy should be identified for each individual patient prior to the start of treatment. Preoperative embolization has generally been considered a safe and effective means of reducing intraoperative blood loss with recent studies and advances in technique reported. Update on indications, contraindications, technique, and efficacy, as well as prognostic factors and complications of preoperative embolization of bone metastases will be reviewed. New trends such as transradial arterial access and usage of liquid embolic agents will be discussed. Large tumor size, increased preprocedural tumor vascularity, longer embolization-to-surgery interval, and radical surgical procedures are associated with greater intraoperative blood loss and prolonged operative time. An accurate, noninvasive method to evaluate tumor vascularity prior to angiography is needed to identify patients who are most likely to benefit from preoperative embolization. Particular attention will be paid to skeletal metastases and spinal metastases as each has its own set of complexity.

Outcomes in the radiosurgical management of metastatic spine disease

Purpose

Stereotactic body radiation therapy (SBRT) is a common treatment option for patients with metastatic tumors of the spine. The optimal treatment-, tumor-, and patient-specific characteristics necessary to achieve durable outcomes remain less well understood given the heterogeneous nature of the patient population this modality typically serves. The objective of this analysis was to better understand the determinants underlying SBRT spine treatment outcomes.

Methods and Materials

A total of 127 patients with 287 spine tumors were treated between March 2010 and May 2015. The median total doses for single-fraction and hypofractionated courses of treatment were 16 Gy (range, 16-20 Gy) and 24 Gy (range, 16-40 Gy), respectively. Radiologic local control and numeric pain score data were measured, and univariate and multivariate analyses were done to determine factors predictive of treatment response.

Results

Median follow-up was 5.9 months (range, 1-61 months). Radiologic local control was achieved in 84.7% of patients at 6 months and in 74.7% of patients at 1 year. Local control was found to be affected by the Spinal Instability Neoplastic Score, and was worse in patients with scores ≥7 (hazard ratio [HR]: 4.25; 95% confidence interval [CI], 1.57-11.51). Patients who required upfront surgical intervention to alleviate spinal cord compression, address mechanical spinal instability, or both had worse local control than those who did not require surgery (HR: 2.32; 95% CI, 1.04-5.17). Patients treated with a hypofractionated course compared with a single fraction had worse radiologic local control (HR: 2.63; 95% CI, 1.27-5.45). No patients developed radiation-induced myelitis after treatment, and the vertebral compression fracture rate was 9.1% after SBRT.

Conclusions

Patients with potentially unstable spines or needing upfront spinal surgery before SBRT are less likely to achieve durable radiologic local control. Additionally, patients treated with single-fraction regimens have improved local control compared with those treated with hypofractionated radiation.

Clinical Significance of Preoperative Embolization for Non-Hypervascular Metastatic Spine Tumors

OBJECTIVE

The efficacy of preoperative embolization for hypervascular metastatic spine disease (MSD) such as renal cell and thyroid cancers has been reported. However, the debate on the efficacy of preoperative embolization for non-hypervascular MSD still remains unsettled. The purpose of this study is to determine whether preoperative embolization for non-hypervascular MSD decreases perioperative blood loss.

METHODS

A total of 79 patients (36 cases of preoperative embolization and 43 cases of non-embolization) who underwent surgery for metastatic spine lesions were included. Representative hypervascular tumors such as renal cell and thyroid cancers were excluded. Intraoperative and perioperative estimated blood losses (EBL), total number of transfusion and calibrated EBL were recorded in the embolization and non-embolization groups. The differences in EBL were also compared along with the type of surgery. In addition, the incidence of Adamkiewicz artery and complications of embolization were assessed.

RESULTS

The average age of 50 males and 29 females was 57.6±13.5 years. Lung (30), hepatocellular (14), gastrointestinal (nine) and others (26) were the primary cancers. The demographic data was not significantly different between the embolization and the non-embolization groups. There were no significant differences in intraoperative EBL, perioperative EBL, total transfusion and calibrated EBL between two groups. However, intraoperative EBL and total transfusion in patients with preoperative embolization were significantly lower than in non-embolization in the corpectomy group (1645.5 vs. 892.6 mL, p=0.017 for intraoperative EBL and 6.1 vs. 3.9, p=0.018 for number of transfusion). In addition, the presence of Adamkiewicz artery at the index level was noted in two patients. Disruption of this major feeder artery resulted in significant changes in intraoperative neuromonitoring.

CONCLUSION

Preoperative embolization for non-hypervascular MSD did not reduce perioperative blood loss. However, the embolization significantly reduced intraoperative bleeding and total transfusion in corpectomy group. Moreover, the procedure provided insights into the anatomy of tumor and spinal cord vasculature.

Accuracy of iodine density thresholds for the separation of vertebral bone metastases from healthy-appearing trabecular bone in spectral detector computed tomography

PURPOSE

To evaluate quantitative iodine density mapping (IDM) with spectral detector computed tomography (SDCT) as a quantitative biomarker for separation of vertebral trabecular bone metastases (BM) from healthy-appearing trabecular bone (HTB).

MATERIALS AND METHODS

IRB-approved retrospective single-center-study of portal venous SDCT datasets acquired between June 2016 and March 2017. Inclusion of 43 consecutive cancer patients with BM and 40 without. Target lesions and non-affected control vertebrae were defined using follow-up imaging, MRI, and/or bone scintigraphy. ID and standard deviation were determined with ROI measures by two readers in (a) bone metastases, (b) HTB of BM patients and controls, and (c) ID of various vessels. Volumetric bone mineral density (vBMD) of the lumbar spine and age were recorded. Multivariate ROC analyses und Wilcoxon test were used to determine thresholds for separation of BM and HTB. p < 0.05 was considered significant.

RESULTS

ID measurements of 40 target lesions and 83 reference measurements of HTB were acquired. Age (p < 0.0001) and vBMD (p < 0.05) affected ID measurements independently in multivariate models. There were significant differences of ID between metastases (n = 43) and HTB ID (n = 124; mean 5.5 ± 0.9 vs. 3.5 ± 0.9; p < 0.0001), however, with considerable overlap. In univariate analysis, increased ID discriminated bone lesions (AUC 0.90) with a maximum combined specificity/sensitivity of 77.5%/90.7% when applying a threshold of 4.5 mg/ml. Multivariate regression models improved significantly when considering vBMD, the noise of ID, and vertebral venous ID (AUC 0.98).

CONCLUSION

IDM of SDCT yielded a statistical separation of vertebral bone lesions and HTB. Adjustment for confounders such as age and lumbar vBMD as well as for vertebral venous ID and lesion heterogeneity improved discrimination of trabecular lesions.

KEY POINTS

• SDCT iodine density mapping provides the possibility for quantitative analysis of iodine uptake in tissue, which allows to differentiate bone lesions from healthy bone marrow. • Age and vBMD have a significant impact on iodine density measurements. • Iodine density measured in SDCT yielded highest sensitivity and specificity for the statistical differentiation of vertebral trabecular metastases and healthy trabecular bone using an iodine density threshold of 4.5 mg/ml (most performant)-5.0 mg/ml (optimized for specificity).

Managing the cervical spine in multiple myeloma patients

Discuss the relevant literature on surgical and nonsurgical treatments for multiple myeloma (MM) and their complementary effects on overall treatment. Existing surgical algorithms designed for neoplasia of the spine may not suit the management of spinal myeloma. Less than a fifth of metastatic, including myelomatous lesions, occur in the cervical spine but have a poorer prognosis and surgery in this area carries a higher morbidity. With the advances of chemotherapy, early access to radiotherapy, early orthosis management, and high definition imaging, including CT and MRI, surgical indications in MM have changed. Medical decompression (or oncolysis), including in the presence of neurological deficit and orthotic stabilization, are proving viable nonsurgical options to manage MM. A key to decision making is the assessment and monitoring of biomechanical spinal stability as part of a multidisciplinary approach.

The Role of Prognostic Scoring Systems in Assessing Surgical Candidacy for Patients With Vertebral Metastasis: A Narrative Review

STUDY DESIGN

Narrative review.

OBJECTIVES

To review the relevant literature regarding scoring systems for vertebral metastases and quantify their role in contemporary orthopedic practice.

METHODS

A literature search of PubMed, Google Scholar, and Embase was performed on February 7, 2017. Eight scoring systems were selected for detailed review-7 of which were scores focused solely on patient prognosis (Tokuhashi, Tomita, Bauer, Oswestry Spinal Risk Index, Van der Linden, Rades, and Katagiri). The eighth system reviewed was the Spinal Instability Neoplastic Score, which examines for impending spinal instability in patients with vertebral metastases and represents a novel approach compared with hitherto scoring systems.

RESULTS

The Bauer and Oswestry Spinal Risk Index have the most accurate prognostic predictive ability, with the newer Oswestry Spinal Risk Index being favored by the contemporary literature as it demands less investigation and is therefore more readily accessible. There was a growing trend in studies designed to customize scoring systems for individual cancer pathological subtypes. The Spinal Instability Neoplastic Score shows good reliability for predicting instability among surgeons and oncologists.

CONCLUSIONS

The increased understanding of cancer pathology and subsequent development of customized treatments has led to prolonged survival. For patients with vertebral metastases, this affects surgical candidacy not only on the basis of prognosis but also provides prolonged opportunity for the development of spinal instability. Scoring systems have a useful guidance role in these deciding for/against surgical intervention, but in order to remain contemporary ongoing review, development, and revalidation is mandatory.

Management - spinal metastases

Due to a worldwide increase of cancer incidence and a longer life expectancy of patients with metastatic cancer, a rise in the incidence of symptomatic vertebral metastases has been observed. Metastatic spinal disease is one of the most dreaded complications of cancer as it is not only associated with severe pain, but also with paralysis, sensory loss, sexual dysfunction, urinary and fecal incontinency when the neurologic elements are compressed. Rapid diagnosis and treatment have been shown to improve both the quality and length of remaining life. This chapter on vertebral metastases with epidural disease and intramedullary spinal metastases will be discussed in terms of epidemiology, pathophysiology, demographics, clinical presentation, diagnosis, and management. With respect to treatment options, our review will summarize the evolution of conventional palliative radiation to modern stereotactic body radiotherapy for spinal metastases and the surgical evolution from traditional open procedures to minimally invasive spine surgery. Lastly, we will review the most common clinical prediction and decision rules, framework and algorithms, and guidelines that have been developed to guide treatment decision making.

Female Human Spines with Simulated Osteolytic Defects: CT-based Structural Analysis of Vertebral Body Strength

Purpose To evaluate a CT structural analysis protocol (SAP) for estimating the strength of human female cadaveric spines with lytic lesions. Materials and Methods Osteolytic foci was created in the middle vertebra of 44 thoracic and lumbar three-level segments from 11 female cadavers (age range, 50-70 years). The segments underwent CT by using standard clinical protocol and their failure strength was assessed at CT SAP. The spines were mechanically tested to failure in pure axial compression or in compression with torsion. The relationships of defect size, bone mineral density, and predicted failure load (at CT SAP) with measured vertebral strength were assessed with linear regression. Analysis of variance and Tukey test were used to evaluate the effect of region and mechanical test on spine strength. Results With axial compression, CT SAP predictions of vertebral strength correlated with the thoracic (r = 0.84; P < .001) and lumbar (r = 0.85; P < .001) segment-measured strength. Bone mineral density correlated with the lumbar (r = 0.64; P = .003) and thoracic (r, 0.51; P = .050) strength. At compression with torsion, CT SAP predictions of strength were moderately correlated with vertebral strength (r = 0.66; P = .018). At compression with torsion, bone mineral density was not correlated with spinal strength (thoracic and lumbar: r = 0.31 and r = 0.26, respectively; P = .539 and .610, respectively). The lytic focus size (range, 28%-41%) was not associated with vertebral strength. Conclusion CT SAP assessment of strength in vertebrae with lytic lesions correlated with the measured strength of female vertebral bodies. ^© RSNA, 2018 Online supplemental material is available for this article.

Sternal metastasis - the forgotten column and its effect on thoracic spine stability

Sternal metastases are not studied extensively in the literature. There is a paucity of information on their role in metastatic disease. The concept of the fourth column was described by Berg in 1993, and has been proven in case report, clinically and biomechanical studies. The role of the sternum as a support to the thoracic spine is well documented in the trauma patients, but not much is known about its role in cancer patients. This review examines what is known on the role of the fourth column. Following this we have identified two likely scenarios that sternal metastases may impact management: (1) sternal pathological fracture increases the mobility of the semi-rigid thorax with the loss of the biomechanical support of the sternum-rib-thoracic spine complex; and (2) a sternal metastasis increases the risk of fracture, and while being medical treated the thoracic spine should be monitored for acute kyphosis and neurological injury secondarily to the insufficiency of the fourth column.

Effect of Polyether Ether Ketone on Therapeutic Radiation to the Spine: A Pilot Study

STUDY DESIGN

Cadaveric model.

OBJECTIVES

To compare the effect of PEEK versus conventional implants on scatter radiation to a simulated tumor bed in the spine SUMMARY OF BACKGROUND DATA.: Given the highly vasculature nature of the spine, it is the most common place for bony metastases. After surgical treatment of a spinal metastasis, adjuvant radiation therapy is typically administered. Radiation dosing is primarily limited by toxicity to the spinal cord. The scatter effect caused by metallic implants decreases the accuracy of dosing and can unintentionally increase the effective dose seen by the spinal cord. This represents a dose-limiting factor for therapeutic radiation postoperatively.

METHODS

A cadaveric thorax specimen was utilized as a metastatic tumor model with two separate three-level spine constructs (one upper thoracic and one lower thoracic). Each construct was examined independently. All four groups compared included identical posterior instrumentation. The anterior constructs consisted of either: an anterior polyether ether ketone (PEEK) cage, an anterior titanium cage, an anterior bone cement cage (polymethyl methacrylate), or a control group with posterior instrumentation alone. Each construct had six thermoluminescent detectors to measure the radiation dose.

RESULTS

The mean dose was similar across all constructs and locations. There was more variability in the upper thoracic spine irrespective of the construct type. The PEEK construct had a more uniform dose distribution with a standard deviation of 9.76. The standard deviation of the others constructs was 14.26 for the control group, 19.31 for the titanium cage, and 21.57 for the cement (polymethyl methacrylate) construct.

CONCLUSION

The PEEK inter-body cage resulted in a significantly more uniform distribution of therapeutic radiation in the spine when compared with the other constructs. This may allow for the application of higher effective dosing to the tumor bed for spinal metastases without increasing spinal cord toxicity with either fractionated or hypofractionated radiotherapy.

LEVEL OF EVIDENCE

N/A.

Impact of cervicothoracic region stereotactic spine radiosurgery on adjacent organs at risk

OBJECTIVE

Stereotactic radiosurgery (SRS) of the spine is a conformal method of delivering a high radiation dose to a target in a single or few (usually ≤ 5) fractions with a sharp fall-off outside the target volume. Although efforts have been focused on evaluating spinal cord tolerance when treating spinal column metastases, no study has formally evaluated toxicity to the surrounding organs at risk (OAR), such as the brachial plexus or the oropharynx, when performing SRS in the cervicothoracic region. The aim of this study was to evaluate the radiation dosimetry and the acute and delayed toxicities of SRS on OAR in such patients.

METHODS

Fifty-six consecutive patients (60 procedures) with a cervicothoracic spine tumor involving segments within C5–T1 who were treated using single-fraction SRS between February 2006 and July 2014 were included in the study. Each patient underwent CT simulation and high-definition MRI before treatment. The clinical target volume and OAR were contoured on BrainScan and iPlan software after image fusion. Radiation toxicity was evaluated using the common toxicity criteria for adverse events and correlated to the radiation doses delivered to these regions. The incidence of vertebral body compression fracture (VCF) before and after SRS was evaluated also.

RESULTS

Metastatic lesions constituted the majority (n = 52 [93%]) of tumors treated with SRS. Each patient was treated with a median single prescription dose of 16 Gy to the target. The median percentage of tumor covered by SRS was 93% (maximum target dose 18.21 Gy). The brachial plexus received the highest mean maximum dose of 17 Gy, followed by the esophagus (13.8 Gy) and spinal cord (13 Gy). A total of 14 toxicities were encountered in 56 patients (25%) during the study period. Overall, 14% (n = 8) of the patients had Grade 1 toxicity, 9% (n = 5) had Grade 2 toxicity, 2% (n = 1) had Grade 3 toxicity, and none of the patients had Grade 4 or 5 toxicity. The most common (12%) toxicity was dysphagia/odynophagia, followed by axial spine pain flare or painful radiculopathy (9%). The maximum radiation dose to the brachial plexus showed a trend toward significance (p = 0.066) in patients with worsening post-SRS pain. De novo and progressive VCFs after SRS were noted in 3% (3 of 98) and 4% (4 of 98) of vertebral segments, respectively.

CONCLUSIONS

From the analysis, the current SRS doses used at the Cleveland Clinic seem safe and well tolerated at the cervicothoracic junction. These preliminary data provide tolerance benchmarks for OAR in this region. Because the effect of dose-escalation SRS strategies aimed at improving local tumor control needs to be balanced carefully with associated treatment-related toxicity on adjacent OAR, larger prospective studies using such approaches are needed.

Preoperative prediction for regaining ambulatory ability in paretic non-ambulatory patients with metastatic spinal cord compression

STUDY DESIGN

Retrospective multicenter study.

OBJECTIVES

To analyze the predictive factors for postoperative ambulatory recovery in paretic non-ambulatory patients with metastatic spinal cord compression (MSCC).

SETTING

Japan.

METHODS

Eighty-two consecutive patients (74.4% men; mean age, 66.2 years) who could not walk before surgery due to cervical or thoracic MSCC and underwent posterior decompressive surgery between 2003 and 2014 were included. Patients were divided into two groups according to ambulatory status at 6 weeks after surgery: recovery (group R) and non-recovery (group NR). To evaluate the speed of progression of motor deficits, we assessed the period from onset of neurological symptoms to gait inability (T1).

RESULTS

Fifty patients (61.0%) regained the ability to walk (group R). The period of T1 demonstrated a positive correlation with probability of ambulatory recovery (P=0.00; Kendall's tau-b=0.38), and a receiver operating characteristic curve analysis showed that the cutoff value of T1 was 5 days (area under the curve=0.72; P=0.001). In multivariate analysis, <6 days of T1 was one of the independent risk factors for failing to regain ambulatory ability (odds ratio, 8.74; P=0.00).

CONCLUSIONS

The speed of progression of motor deficits can independently and powerfully predict the chance of postoperative ambulatory recovery as well as previously identified predictors. Since information about the speed of progression can be obtained easily by interviewing patients or family members, even if the patient is in an urgent state, our results will be helpful in clinical decision-making.

Mechanical assessment of the effects of metastatic lytic defect on the structural response of human thoracolumbar spine

To investigate the effects of a clinical lytic defect on the structural response of human thoracolumbar functional spinal unit. A novel CT-compatible mechanical test system was used to image the deformation of a T12-L1 motion segment and measure the change in strain response under compressive loads ranging from 50 to 750 N. A lytic lesion (LM) with cortex involvement (33% by volume) was introduced to the upper vertebral body and the CT experiments were repeated. Finite element models, established from the CT volumes, were used to investigate the defect's effects on the structural response and the state of principal and shear stresses within the affected and adjacent vertebrae. The lytic lesion resulted in severe loss of the vertebral structural competence, resulting in significant, non-linear, and asymmetric increase in the experimentally measured strains and computed stresses within both vertebrae (p < 0.01). At the cortex, the tensile strains were significantly increased, while compressive strains significantly decreased, (p < 0.05). Both the vertebral bone and cortex regions adjacent to the defect showed significant increase in computed compressive, tensile, and shear stresses (p < 0.01). Changes in stress and strain distribution within the affected and adjacent vertebral bone and the experimentally observed bulging and buckling of the vertebral cortices suggested that initiation of catastrophic vertebral failure may occur under load magnitudes encountered in daily living. Although the effect of LM on the global deformation of the spine was well-predicted, our results show that FE predictions of local strain changes must be carefully assessed for clinical relevance. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1808-1819, 2016.

Continuous Cervical Epidural Analgesia in Metastatic Spinal Cord Compression

Metastatic spinal cord compression is a devastating complication of cancer. Patients may often require high doses of opioids that may cause side effects, myoclonus being one such. A 63-year-old male suffering from malignant spinal cord compression was admitted to our institution. The primary team managed him conservatively with pharmacotherapy with no relief of pain, and he experienced myoclonus and sedation as adverse effects. A continuous cervical epidural catheter with local anesthetic infusion was inserted for 5 days to control his pain. This relieved his pain, which was sustained even after we removed the epidural catheter on day 5, for up to 64 days until the time of his death. Continuous cervical epidural local anesthetic infusions may help with refractory pain by deafferentation of noxious stimuli. Central neuraxial blocks may be a valuable rescue in selected patients.

Augmentation of failed human vertebrae with critical un-contained lytic defect restores their structural competence under functional loading: An experimental study

BACKGROUND

Lytic spinal lesions reduce vertebral strength and may result in their fracture. Vertebral augmentation is employed clinically to provide mechanical stability and pain relief for vertebrae with lytic lesions. However, little is known about its efficacy in strengthening fractured vertebrae containing lytic metastasis.

METHODS

Eighteen unembalmed human lumbar vertebrae, having simulated uncontained lytic defects and tested to failure in a prior study, were augmented using a transpedicular approach and re-tested to failure using a wedge fracture model. Axial and moment based strength and stiffness parameters were used to quantify the effect of augmentation on the structural response of the failed vertebrae. Effects of cement volume, bone mineral density and vertebral geometry on the change in structural response were investigated.

FINDINGS

Augmentation increased the failed lytic vertebral strength [compression: 85% (P<0.001), flexion: 80% (P<0.001), anterior-posterior shear: 95%, P<0.001)] and stiffness [(40% (P<0.05), 53% (P<0.05), 45% (P<0.05)]. Cement volume correlated with the compressive strength (r(2)=0.47, P<0.05) and anterior-posterior shear strength (r(2)=0.52, P<0.05) and stiffness (r(2)=0.45, P<0.05). Neither the geometry of the failed vertebrae nor its pre-fracture bone mineral density correlated with the volume of cement.

INTERPRETATION

Vertebral augmentation is effective in bolstering the failed lytic vertebrae compressive and axial structural competence, showing strength estimates up to 50-90% of historical values of osteoporotic vertebrae without lytic defects. This modest increase suggests that lytic vertebrae undergo a high degree of structural damage at failure, with strength only partially restored by vertebral augmentation. The positive effect of cement volume is self-limiting due to extravasation.

Effect of the metastatic defect on the structural response and failure process of human vertebrae: an experimental study

BACKGROUND

Pathologic vertebral fractures are associated with intractable pain, loss of function and high morbidity in patients with metastatic spine disease. However, the failure mechanisms of vertebrae with lytic defects and the failed vertebrae's ability to retain load carrying capacity remain unclear.

METHODS

Eighteen human thoracic and lumbar vertebrae with simulated uncontained bone defects were tested under compression-bending loads to failure. Failure was defined as 50% reduction in vertebral body height. The vertebrae were allowed to recover under load and re-tested to failure using the initial criteria. Repeated measure ANOVA was used to test for changes in strength and stiffness parameters.

FINDINGS

Vertebral failure occurred via buckling and fracture of the cortex around the defect, followed by collapse of the defect region. Compared to the intact vertebrae, the failed vertebrae exhibited a significant loss in compressive strength (59%, p<0.001), stiffness (53%, p<0.05) and flexion (70%, p<0.01) strength. Significant reduction in anterior-posterior shear (strength (63%, p<0.01) and stiffness (67%, p<0.01)) and lateral bending strength (134%, p<0.05) were similarly recorded. In the intact vertebrae, apart from flexion strength (r(2)=0.63), both compressive and anterior-posterior shear strengths were weakly correlated with their stiffness parameters (r(2)=0.24 and r(2)=0.31). By contrast, in the failed vertebrae, these parameters were strongly correlated, (r(2)=0.91, r(2)=0.86, and r(2)=0.92, p<0.001 respectively).

INTERPRETATION

Failure of the vertebral cortex at the defect site dominated the initiation and progression of vertebral failure with the vertebrae failing via a consolidation process of the vertebral bone. Once failed, the vertebrae showed remarkable loss of load carrying capacity.

Long-term survival of a patient with lung cancer metastasis to the spine following surgical treatment combined with radiation and epithelial growth factor receptor inhibitor therapy: A case report

The prognosis of patients with lung cancer metastasis to the spine is poor, and the choice of surgery is questionable based on the aggressiveness of the disease. The present study describes a case of a 56-year-old male with metastatic spinal cord compression. The patient underwent surgery for posterior decompression and internal fixation, in addition to receiving postoperative radiation and epidermal growth factor receptor (EGFR) inhibitor medication. After 24 months, positron emission tomography-computed tomography scan showed a reduction in the left upper lobe mass in the short axis and inactivation of the neoplasm in the left upper lobe and T9 vertebra. Based on these promising results, it is suggested that orthopedic oncologists consider the combination of radiation and EGFR inhibitor therapy with surgery for the treatment of lung cancer metastasis to the spine.

The Spine Instability Neoplastic Score: an independent reliability and reproducibility analysis

BACKGROUND

Metastatic vertebral instability has not yet been clearly defined in the literature; there still exists a paucity of reliable criteria to assess the risk of vertebral collapse.

PURPOSE

We performed an independent interobserver and intraobserver agreement evaluation of the Spine Instability Neoplastic Score (SINS) and correlated the score with selected clinical cases and the treatment they received.

STUDY DESIGN

Independent reliability study for the newly created SINS.

PATIENT SAMPLE

Thirty patients who underwent either radiotherapy alone or surgery followed by radiotherapy were randomly selected from the orthopedic surgery and radiotherapy department's databases.

OUTCOME MEASURES

Patients were rated and classified for spinal stability using SINS. Intraclass correlation coefficient (ICC) and Fleiss's kappa measures were occupied for reliability analysis.

METHODS

Patients who underwent either radiotherapy alone or surgery followed by radiotherapy were randomly selected and classified for spinal stability using the SINS by orthopedic surgeons and nonorthopedic oncology specialists. ICC and Fleiss's kappa were calculated for inter- and intraobserver agreement. A comparative analysis of SINS and the actual management was also conducted.

RESULTS

Interobserver ICC reliability for the SINS was 0.79; κ values for location, pain, bone quality, alignment, vertebral body collapse, and posterolateral involvement were 0.81, 0.58, 0.21, 0.45, 0.42, and 0.29 respectively. Intraobserver ICC for the SINS scores was 0.96; ICC values for the same components were 0.98, 0.98, 0.87, 0.88, 0.92, and 0.86, respectively. Potentially unstable lesions (SINS score≥7) were operated on in 62.5%.

CONCLUSIONS

SINS seem to be a reproducible tool that could be used equally by multiple specialists to estimate metastatic vertebral stability; however, prospective clinical validation is still pending.

Laminectomy without instrumentation for surgical treatment of metastatic spinal cord compression

OBJECTIVE: To analyze the development of mechanical complications as a result of spinal decompression or cauda equina in patients with metastatic tumors of the spine via laminectomy or laminoartrectomy without fixation. METHODS: We studied the medical records of all patients submitted to spine decompression with laminectomy without fixation. The decompression was indicated to treat cord compression or cauda equina caused by metastatic tumors. Patients were evaluated for the development of postoperative mechanical instability by comparing the preoperative radiological examinations with the latest one available in the medical record review.. In these images, we evaluated the emergence of new deformity in the sagittal or coronal planes and translational deformity. We consider new deformity, signs of deformity greater or equal to 5° in the coronal or sagittal planes and signs of increased vertebral translation greater than or equal to 3 mm. RESULTS: No patient developed radiological instability in the period evaluated with an average follow-up of 163.24 days (3-663). The complication rate in our sample was not higher than the previously reported in the literature. CONCLUSION: Isolated laminectomy at one or more levels is a safe procedure for the treatment of metastatic spinal cord compression where the spine is judged stable before surgery.

A rat model of metastatic spinal cord compression using human prostate adenocarcinoma: histopathological and functional analysis

BACKGROUND CONTEXT

Cancer is a major global public health problem responsible for one in every four deaths in the United States. Prostate cancer alone accounts for 29% of all cancers in men and is the sixth leading cause of death in men. It is estimated that up to 30% of patients with cancer will develop metastatic disease, the spine being one of the most frequently affected sites in patients with prostate cancer.

PURPOSE

To study this condition in a preclinical setting, we have created a novel animal model of human metastatic prostate cancer to the spine and have characterized it histologically, functionally, and via bioluminescence imaging.

STUDY DESIGN

Translational science investigation of animal model of human prostate cancer in the spine.

METHODS

Luciferase-positive human prostate tumor cells PC3 (PC3-Luc) were injected in the flank of athymic male rats. PC3-Luc tumor samples were then implanted into the L5 vertebral body of male athymic rats (5 weeks old). Thirty-two rats were randomized into three surgical groups: experimental, control, and sham. Tumor growth was assessed qualitatively and noninvasively via bioluminescence emission, upon luciferin injection. To determine the functional impact of tumor growth in the spine, rats were evaluated for gait abnormalities during gait locomotion using video-assisted gait analysis. Rats were euthanized 22 days after tumor implantation, and spines were subjected to histopathological analyses.

RESULTS

Twenty days after tumor implantation, the tumor-implanted rats showed distinct signs of gait disturbances: dragging tail, right- or left-hind limb uncoordination, and absence of toe clearance during forward limb movement. At 20 days, all rats experienced tumor growth, evidenced by bioluminescent signal. Locomotion parameters negatively affected in tumor-implanted rats included stride length, velocity, and duration. At necropsy, all spines showed evidence of tumor growth, and the histological analysis found spinal cord compression and peritumoral osteoblastic reaction characteristic of bony prostate tumors. None of the rats in the sham or control groups demonstrated any evidence of bioluminescence signal or signs of gait disturbances.

CONCLUSIONS

In this project, we have developed a novel animal model of metastatic spine cancer using human prostate cancer cells. Tumor growth, evaluated via bioluminescence and corroborated by histopathological analyses, affected hind limb locomotion in ways that mimic motor deficits present in humans afflicted with metastatic spine disease. Our model represents a reliable method to evaluate the experimental therapeutic approaches of human tumors of the spine in animals. Gait locomotion and bioluminescence analyses can be used as surrogate noninvasive methods to evaluate tumor growth in this model.

Sclerotic lesions of the spine: MRI assessment

Sclerotic (T2 dark) lesions of the spine are infrequent and, as a result, these are often missed or misdiagnosed. Plain films may not be always available during magnetic resonance imaging (MRI) readout. Knowledge of such lesions and their imaging appearances on MRI evaluation is essential for a reader. Additionally, a systematic approach is important to accurately diagnose these lesions. In this article we discuss the various causes of spinal sclerotic lesions, describe their MRI characteristics with relevant case examples, and outline a systematic approach to their evaluation.

Treatment of cervical vertebral (C1) metastasis of lung cancer with radiotherapy: A case report

The present study discusses a patient with C1 vertebral metastasis from adenocarcinoma of the left lung. The patient was a 31-year-old female suffering from neck pain who was referred by her physician. Magnetic resonance imaging revealed osteolytic destruction of the C1 vertebra. Chest and computed tomographic scans revealed lung carcinoma changes involving the left lung. A biopsy confirmed adenocarcinoma of the left lung. Abnormal activity was present in the cervical spine (C1) region in a radionuclide bone scan. The patient was then referred to an oncologist. The spine was stabilized with a rigid collar and a course of radiation therapy and pain medication was initiated immediately. At the 9-month follow-up examination, there was no evidence of progression on the MRI scans and the main neck symptoms had disappeared. At present, the overall survival (OS) time is 11 months. Patients complaining of new onset back or neck pain should be assumed to have vertebral metastasis until proven otherwise. Trivial trauma should be taken seriously in these cases and investigated with appropriate clinical, laboratory and imaging examinations.

A novel animal model of human breast cancer metastasis to the spine: a pilot study using intracardiac injection and luciferase-expressing cells

OBJECT

Metastatic spine disease is prevalent in cancer victims; 10%-30% of the 1.2 million new patients diagnosed with cancer in the US exhibit spinal metastases. Unfortunately, treatments are limited for these patients, as disseminated disease is often refractory to chemotherapy and is difficult to treat with surgical intervention alone. New animal models that accurately recapitulate the human disease process are needed to study the behavior of metastases in real time.

METHODS

In this study the authors report on a cell line that reliably generates bony metastases following intracardiac injection and can be tracked in real time using optical bioluminescence imaging. This line, RBC3, was derived from a metastatic breast adenocarcinoma lesion arising in the osseous spine of a rat following intracardiac injection of MDA-231 human breast cancer cells.

RESULTS

Upon culture and reinjection of RBC3, a statistically significantly increased systemic burden of metastatic tumor was noted. The resultant spine lesions were osteolytic, as demonstrated by small animal CT scanning.

CONCLUSIONS

This cell line generates spinal metastases that can be tracked in real time and may serve as a useful tool in the study of metastatic disease in the spine.

The management of pain in metastatic bone disease

BACKGROUND

Metastatic bone disease is a common cause of pain in cancer patients. A multidisciplinary approach to treatment is often necessary because simplified analgesic regimens may fail in the face of complex pain generators, especially those involved in the genesis of neuropathic pain. From the origins of formalized guidelines by the World Health Organization (WHO) to recent developments in implantable therapies, great strides have been made to meet the needs of these patients.

METHODS

The authors review the existing literature on the pathophysiology and treatment options for pain generated by metastatic bone disease and summarize classic and new approaches.

RESULTS

Relatively recent animal models of malignant bone disease have allowed a better understanding of the intimate mechanisms involved in the genesis of pain, resulting in a mechanistic approach to its treatment. Analgesic strategies can be developed with specific targets in mind to complement the classic, opioid-centered WHO analgesic ladder obtaining improved outcomes and quality of life. Unfortunately, high-quality evidence is difficult to produce in pain medicine, and these concepts are evolving slowly.

CONCLUSIONS

Treatment options are expanding for the challenging clinical problem of painful metastatic bone disease. Efforts are concentrated on developing alternative nonopioid approaches that appear to increase the success rate and improve patients' quality of life.

Complications in the management of metastatic spinal disease

Metastatic spine disease accounts for 10% to 30% of new cancer diagnoses annually. The most frequent presentation is axial spinal pain. No treatment has been proven to increase the life expectancy of patients with spinal metastasis. The goals of therapy are pain control and functional preservation. The most important prognostic indicator for spinal metastases is the initial functional score. Treatment is multidisciplinary, and virtually all treatment is palliative. Management is guided by three key issues; neurologic compromise, spinal instability, and individual patient factors. Site-directed radiation, with or without chemotherapy is the most commonly used treatment modality for those patients presenting with spinal pain, causative by tumours which are not impinging on neural elements. Operative intervention has, until recently been advocated for establishing a tissue diagnosis, mechanical stabilization and for reduction of tumor burden but not for a curative approach. It is treatment of choice patients with diseaseadvancement despite radiotherapy and in those with known radiotherapy-resistant tumors. Vertebral resection and anterior stabilization with methacrylate or hardware (e.g., cages) has been advocated.Surgical decompression and stabilization, however, along with radiotherapy, may provide the most promising treatment. It stabilizes the metastatic deposited areaand allows ambulation with pain relief. In general, patients who are nonambulatory at diagnosis do poorly, as do patients in whom more than one vertebra is involved. Surgical intervention is indicated in patients with radiation-resistant tumors, spinal instability, spinal compression with bone or disk fragments, progressive neurologic deterioration, previous radiation exposure, and uncertain diagnosis that requires tissue diagnosis. The main goal in the management of spinal metastatic deposits is always palliative rather than curative, with the primary aim being pain relief and improved mobility. This however, does not come without complications, regardless of the surgical intervention technique used. These complication range from the general surgical complications of bleeding, infection, damage to surrounding structures and post operative DT/PE to spinal specific complications of persistent neurologic deficit and paralysis.

The "shadow sign": a radiographic differentiation of stainless steel versus titanium spinal instrumentation in spine surgery

BACKGROUND

Stainless steel spinal instrumentation has been supplanted in recent years by titanium instrumentation. Knowing whether stainless steel or titanium was used in a previous surgery can guide clinical decision making processes, but frequently the clinician has no way to know what type of metal was used. We describe the radiographic "shadow sign," in which superimposed titanium rods and screws remain radiolucent enough that the contour of the underlying components can be seen on a lateral radiograph, whereas superimposed stainless steel rods and screws are completely radiopaque. This technique was evaluated using a retrospective, randomized, and blinded radiographic comparison of titanium and stainless steel spinal instrumentation. The objective was to determine whether the "shadow sign" can reliably differentiate titanium from stainless steel spinal instrumentation.

METHODS

Lateral radiographs from 16 cases of posterior spinal instrumentation (6 titanium, 6 stainless steel, and 2 replicates of each to assess intraobserver reliability) were randomly selected from a database of cases performed for pediatric scoliosis in a university setting from 2005 to 2009. The cases were randomized then shown to 19 orthopaedic surgery residents, 1 spine fellow, and 2 spine attendings. After the "shadow sign" was described, the surgeons were asked to determine what type of metal each implant was made of.

RESULTS

The κ value for both stainless steel and titanium versus the gold standard was 0.83 [standard error (SE) = 0.053], indicating excellent agreement. The κ value for agreement between raters was 0.71 (SE = 0.016) and the κ value for agreement within raters was 0.70 (SE = 0.016), both of which indicated substantial agreement.

CONCLUSIONS

The "shadow sign" can help a clinician differentiate titanium from stainless steel spinal instrumentation based on radiographic appearance alone. Furthermore, our study reveals that the level of experience in diagnosing spinal lateral radiographs also enhances the use of the "shadow sign" indicator.

LEVEL OF EVIDENCE

The method proposed to differentiate titanium from stainless steel falls within the diagnostic studies domain. As unaltered randomization was used to enroll radiographs and the procedure was systematic, this study may be classified in the Level II category.

Metastatic spine disease in the elderly: diagnostic and management considerations

Metastatic spine disease is becoming a more frequent problem in cancer patients as advancements in treatment for primary tumors prolong patient survival. Elderly patients over 60 years of age make up the majority of these cases, with the incidence of metastatic disease several folds higher in the elderly than in any other age group. These patients are also the most challenging group to treat, given higher rates of comorbidities and decreased tolerance to medical, surgical and radiation therapies. Advancements in therapeutic strategies, including minimally invasive surgeries and stereotactic radiosurgery, have provided increasingly attractive treatment options for elderly patients owing to their decreased procedure-associated morbidity. This article will discuss efficacy and limitations of conventional, as well as more recent, treatment modalities with an emphasis on their role in the management of elderly patients.

Identifying myelopathy caused by thoracic syringomyelia: a case report

Myelopathy is a form of neurological disease caused by compression of the spinal cord. Upper and lower quarter screens are commonly used in identifying myelopathy, although most of the screen components demonstrate poor or unstudied diagnostic value. The purpose of this case report is to describe the diagnostic process in detecting syringomyelia, an intramedullary lesion that may cause myelopathy. The patient was a 47-year-old female with a thoracic syrinx that was discovered by spinal magnetic resonance imaging (MRI) following a complicated and delayed clinical diagnostic course. Following surgical intervention and a two-week inpatient rehabilitation stay, the patient was discharged using a rolling walker for ambulation and was performing most transfers with modified independence. A complicating pattern of signs and symptoms combined with a diagnostic process guided by poorly studied screen components demonstrates the diagnostic dilemma associated with identifying the cause of myelopathy within the thoracic spine. This also indicates the need for further investigation of individual and clustered components of the neurological screen to improve the ability to identify patients in need of complete imaging studies in a more timely fashion.

Spinal instability neoplastic score: an analysis of reliability and validity from the spine oncology study group

PURPOSE

Standardized indications for treatment of tumor-related spinal instability are hampered by the lack of a valid and reliable classification system. The objective of this study was to determine the interobserver reliability, intraobserver reliability, and predictive validity of the Spinal Instability Neoplastic Score (SINS).

METHODS

Clinical and radiographic data from 30 patients with spinal tumors were classified as stable, potentially unstable, and unstable by members of the Spine Oncology Study Group. The median category for each patient case (consensus opinion) was used as the gold standard for predictive validity testing. On two occasions at least 6 weeks apart, each rater also scored each patient using SINS. Each total score was converted into a three-category data field, with 0 to 6 as stable, 7 to 12 as potentially unstable, and 13 to 18 as unstable.

RESULTS

The κ statistics for interobserver reliability were 0.790, 0.841, 0.244, 0.456, 0.462, and 0.492 for the fields of location, pain, bone quality, alignment, vertebral body collapse, and posterolateral involvement, respectively. The κ statistics for intraobserver reliability were 0.806, 0.859, 0.528, 0.614, 0.590, and 0.662 for the same respective fields. Intraclass correlation coefficients for inter- and intraobserver reliability of total SINS score were 0.846 (95% CI, 0.773 to 0.911) and 0.886 (95% CI, 0.868 to 0.902), respectively. The κ statistic for predictive validity was 0.712 (95% CI, 0.676 to 0.766).

CONCLUSION

SINS demonstrated near-perfect inter- and intraobserver reliability in determining three clinically relevant categories of stability. The sensitivity and specificity of SINS for potentially unstable or unstable lesions were 95.7% and 79.5%, respectively.