Essential Concepts for the Management of Metastatic Spine Disease: What the Surgeon Should Know and Practice

Combined Rigid-Flexible Multibody Analysis Reveals Reduced Pedicle Screw Loads in Short-Segment Fixation for Decompressed Lumbar Spine Stabilization

BACKGROUND

Spinal cord compression in patients with vertebral metastases often requires surgical decompression with spinal fixation. Recent studies reported increased implant failures due to mechanical complications, raising concerns about current clinical practices. Long-segment fixation (Lf) is commonly employed to enhance mechanical stability and reduce the severity of pedicle screw failure. The study investigates how the number of vertebral levels involved in fixation affects the loads on pedicle screw anchorages in a fatigue-related displacement domain.

METHOD

Using a rigid-flexible multibody approach, a non-linear T12-S1 model was employed to simulate two fixation types following L3 posterior decompression surgery: Lf spanning two levels above and below the decompression site (L1, L2, L4, and L5) and a short-segment fixation (Sf) involving only adjacent vertebrae. Internal reactions at the rod-pedicle screw anchorages were estimated in terms of pullout, shear forces, and bending moments. The range of motion analysed (flexion: 22°, extension: 8°, lateral bending: 12°, axial rotation: 5°) was confined to the "Cone of Economy", representing a small-displacement volume where loads are assumed cyclically exchanged.

RESULTS

Lf exhibited up to fivefold higher reactions than Sf, with a heterogeneous shear force distribution: middle screws appeared shielded, while extremity screws were overloaded (~400 N, comparable to experimental fatigue strength). Pullout forces remained within safe limits (< 150 N).

CONCLUSIONS

The rigid-flexible multibody approach effectively estimated internal loads in the implant-spine constructs under dynamic conditions. The findings highlight the long-term implications of Lf, demonstrating that involving more vertebral levels triggers adverse loads on pedicle screws, potentially compromising implant durability.

Prognostic Value of Lumbar Muscle Morphometrics for Survival of Patients with Spinal Metastasis: A Systematic Review and Meta-Analysis

BACKGROUND

Spinal metastasis, a prevalent complication of advanced malignancy, poses significant challenges in patient management due to its potential to compromise spinal stability and quality of life. Accurate prognostication is crucial for tailored therapeutic strategies. This meta-analysis aimed to evaluate the prognostic significance of sarcopenia and lumbar muscle morphometrics in patients with spinal metastasis.

METHODS

Electronic databases, including PubMed, Embase, and CENTRAL, were searched up to August 2024. Studies were included if they reported quantitative data on sarcopenia or lumbar muscle morphometric parameters and survival outcomes in patients with spinal metastasis. A quantitative meta-analysis was performed with hazard ratio as the effect size. Heterogeneity was assessed using the Cochran Q test and I2 statistic. Publication bias was evaluated through funnel plot symmetry and Egger's and Begg's regression tests.

RESULTS

Our search identified 17 retrospective cohort studies comprising 3023 patients. Various parameters were employed to assess sarcopenia, encompassing cross-sectional area (CSA) of the psoas muscles (left, right, total, or averaged), the ratio of psoas CSA to vertebral CSA, the ratio of psoas CSA to squared body height, and densities of the psoas or paravertebral muscles. Meta-analysis revealed that total/mean psoas area, when grouped by tertiles or medians, held independent prognostic value for survival outcomes. The ratio of psoas area to vertebral area also demonstrated significant prognostic value when grouped by tertiles or medians.

CONCLUSIONS

Lumbar muscle morphometrics are independent prognostic factors for survival in patients with spinal metastasis. Integrating of these metrics into clinical decision-making could enhance personalized therapeutic strategies and prognostic accuracy.

Role of Minimally Invasive Spine Surgery in Spine Oncology

The application of minimally invasive spine surgery (MISS) in degenerative spine disease and deformity has seen rapid growth in the past 20 years. Building on this experience, such methods have been adopted into spine oncology in the past decade, particularly for metastatic disease. The impetus for this growth stems from the benefits of surgical decompression combined with radiation treatment in patients with metastatic disease in conjunction with the need for less morbid interventions in a patient population with limited life expectancy. The result of these two realizations was the application of minimally invasive techniques for the treatment of spine tumors including re-establishment of spinal stability, decompression of the spinal cord or nerve roots, and restoration of spinal alignment. Technological advancement and improvement in biomaterials have allowed for durable stabilization with short constructs even for patients with poor bone quality. The implementation of navigation and robotic capabilities has transformed MISS by streamlining surgery and further reducing the surgical footprint while laser ablation, endoscopy, and robotic surgery hold the potential to minimize the surgical footprint even further. MISS for intradural tumors is commonly performed, while the role for other primary tumors has yet to be defined. In this article, we describe the evolution of and indications for MISS in spine oncology through a retrospective literature review.

Radiotherapy and surgery: can this combination be further optimized for patients with metastatic spine disease?

This narrative review provides a comprehensive overview of the current status, recent advancements, and future directions in the management of metastatic spine disease using both radiotherapy and surgery. Emphasis has been put on the integrated use of radiotherapy and surgery, incorporating recent developments such as separation surgery, active dose sparing of the surgical field, and the implementation of carbon fiber-reinforced polymer implants. Future studies should explore the effects of minimizing the time between radiotherapy and surgery and investigate the potential of vertebral re-ossification after radiotherapy to obviate the need for stabilization surgery. Concerted efforts should be directed toward fostering multidisciplinary collaboration among radiation oncologists, spine surgeons, and medical oncologists.

Advances in Imaging for Metastatic Epidural Spinal Cord Compression: A Comprehensive Review of Detection, Diagnosis, and Treatment Planning

Metastatic epidural spinal cord compression (MESCC) is a critical oncologic emergency caused by the invasion of metastatic tumors into the spinal epidural space, leading to compression of the spinal cord. If not promptly diagnosed and treated, MESCC can result in irreversible neurological deficits, including paralysis, significantly impacting the patient's quality of life. Early detection and timely intervention are crucial to prevent permanent damage. Imaging modalities play a pivotal role in the diagnosis, assessment of disease extent, and treatment planning for MESCC. Magnetic resonance imaging (MRI) is the current gold standard due to its superior ability to visualize the spinal cord, epidural space, and metastatic lesions. However, recent advances in imaging technologies have enhanced the detection and management of MESCC. Innovations such as functional MRI, diffusion-weighted imaging (DWI), and hybrid techniques like positron emission tomography-computed tomography (PET-CT) and PET-MRI have improved the accuracy of diagnosis, particularly in detecting early metastatic changes and guiding therapeutic interventions. This review provides a comprehensive analysis of the evolution of imaging techniques for MESCC, focusing on their roles in detection, diagnosis, and treatment planning. It also discusses the impact of these advances on clinical outcomes and future research directions in imaging modalities for MESCC. Understanding these advancements is critical for optimizing the management of MESCC and improving patient prognosis.

Boron neutron capture therapy delays the decline in neurological function in a mouse model of metastatic spinal tumors

Metastatic spinal tumors are increasingly prevalent due to advancements in cancer treatment, leading to prolonged survival rates. This rising prevalence highlights the need for developing more effective therapeutic approaches to address this malignancy. Boron neutron capture therapy (BNCT) offers a promising solution by delivering targeted doses to tumors while minimizing damage to normal tissue. In this study, we evaluated the efficacy and safety of BNCT as a potential therapeutic option for spine metastases in mouse models induced by A549 human lung adenocarcinoma cells. The animal models were randomly allocated into three groups: untreated (n = 10), neutron irradiation only (n = 9), and BNCT (n = 10). Each mouse was administered 4-borono-L-phenylalanine (250 mg/kg) intravenously, followed by measurement of boron concentrations 2.5 h later. Overall survival, neurological function of the hindlimb, and any adverse events were assessed post irradiation. The tumor-to-normal spinal cord and blood boron concentration ratios were 3.6 and 2.9, respectively, with no significant difference observed between the normal and compressed spinal cord tissues. The BNCT group exhibited significantly prolonged survival rates compared with the other groups (vs. untreated, p = 0.0015; vs. neutron-only, p = 0.0104, log-rank test). Furthermore, the BNCT group demonstrated preserved neurological function relative to the other groups (vs. untreated, p = 0.0004; vs. neutron-only, p = 0.0051, multivariate analysis of variance). No adverse events were observed post irradiation. These findings indicate that BNCT holds promise as a novel treatment modality for metastatic spinal tumors.

Hematologic Malignancies Influence the Accuracy of Prediction of Survival in Patients With Solid Tumor Spinal Metastases Undergoing Surgery

PURPOSE

There is no consensus on how to identify patients with multiple-level spinal metastases who would benefit from surgery. Previous studies have revealed that patients with hematologic malignancies have a significantly longer median survival time than those with solid tumor spinal metastases. We aimed to compare predictors and survival data between patients with spinal metastases, including hematologic malignancies (all-malignancies group), with only those with nonhematologic malignancies (nonhematologic malignancies group).

MATERIALS AND METHODS

This single-center retrospective study included all patients age >18 years who underwent surgery to treat spinal metastases in our department from 2008 to 2018. The patients' baseline characteristics, treatment modalities, and laboratory results were analyzed. Survival was calculated from the date of surgery to the date of confirmed death. Cox regression analysis was used to identify independent predictors of survival.

RESULTS

The study cohort comprised 186 patients with a mean age of 57.1 ± 13.4 years, 101 of whom were male and 18 of whom had hematologic malignancies. The median survival time was 201 days in the all-malignancies group and 168 days in the nonhematologic malignancies group. Independent predictors of survival differed between the two groups. Eastern Cooperative Oncology Group status and response to preoperative chemotherapy were identified as independent factors in both groups. However, radiosensitivity and CNS metastases were identified only in the all-malignancies group, and tumor growth potential, albumin status, and number of vertebrae were identified only in the nonhematologic malignancies group. The receiver operating characteristics were comparable in the two groups: 0.75 in the all-malignancies group and 0.77 in the nonhematologic malignancies group.

CONCLUSION

Longer survival in patients with hematologic malignancies influences the overall prediction of survival. Tumor-specific prognostic factors may improve the prediction of survival in patients with spinal metastases.

External Validation of an Online Wound Infection and Wound Reoperation Risk Calculator After Metastatic Spinal Tumor Surgery

STUDY DESIGN

This was a single-institutional retrospective cohort study.

OBJECTIVE

Wound infections are common following spine metastasis surgery and can result in unplanned reoperations. A recent study published an online wound complication risk calculator but has not yet undergone external validation. Our aim was to evaluate the accuracy of this risk calculator in predicting 30-day wound infections and 30-day wound reoperations using our operative spine metastasis population.

METHODS

An internal operative database was used to identify patients between 2012 and 2022. The primary outcomes were 1) any surgical site infection and 2) wound-related revision surgery within 30 days following surgery. Patient details were manually collected from electronic medical records and entered into the calculator to determine predicted complication risk percentages. Predicted risks were compared to observed outcomes using receiver operator characteristic (ROC) curves with areas under the curve (AUC).

RESULTS

A total of 153 patients were included. The observed 30-day postoperative wound infection incidence was 5% while the predicted wound infection incidence was 6%. In ROC analysis, good discrimination was found for the wound infection model (AUC = 0.737; P = 0.024). The observed wound reoperation rate was 5% and the predicted wound reoperation rate was 6%. ROC analysis demonstrated poor discrimination for wound reoperations (AUC = 0.559; P = 0.597).

CONCLUSIONS

The online wound-related risk calculator was found to accurately predict wound infections but not wound reoperations within our metastatic spine surgery cohort. We suggest that the model may be clinically useful despite underlying population differences, but further work must be done to generate and validate accurate prediction tools.

Implant and construct decision-making in metastatic spine tumour surgery: a review of current concepts with a decision-making algorithm

STUDY DESIGN

Narrative Review.

OBJECTIVE

Metastatic spine tumour surgery (MSTS) is an important treatment modality of metastatic spinal disease (MSD). Increase in MSTS has been due to improvements in our oncological treatment, as patients have increased longevity and even those with poorer comorbidities are now being considered for surgery. However, there is currently no guideline on how MSTS surgeons should select the appropriate levels to instrument, and which type of implants should be utilised.

METHODS

The current literature on MSTS was reviewed to study implant and construct decision making factors, with a view to write this narrative review. All studies that were related to instrumentation in MSTS were included.

RESULTS

A total of 58 studies were included in this review. We discuss novel decision-making models that should be taken into account when planning for surgery in patients undergoing MSTS. These factors include the quality of bone for instrumentation, the extent of the construct required for MSTS patients, the use of cement augmentation and the choice of implant. Various studies have advocated for the use of these modalities and demonstrated better outcomes in MSTS patients when used appropriately.

CONCLUSION

We have established a new instrumentation algorithm that should be taken into consideration for patients undergoing MSTS. It serves as an important guide for surgeons treating MSTS, with the continuous evolvement of our treatment capacity in MSD.

LEVEL OF EVIDENCE IV

Mexican Multicenter Experience of Metastatic Spinal Disease

Background Spinal metastatic disease is a silent progressive cancer complication with an increasing prevalence worldwide. The spine is the third most common site where solid tumors metastasize. Complications involved in spinal metastasis include root or spinal cord compression, progressing to a declining quality of life as patient autonomy reduces and pain increases. The main objective of this study is to report the incidence of patients and typology of spinal metastases in three reference centers in Mexico. Methodology Retrospective cohorts of patients diagnosed with spinal metastases from January 2010 to February 2017 at the National Cancer Institute, National Rehabilitation Institute, and the Traumatology and Orthopedics Hospital "Lomas Verdes" in Mexico City were analyzed. Results A total of 326 patients (56% males) with spinal metastases were reported. The mean age was 58.06 ± 14.05 years. The main sources of spinal metastases were tumors of unknown origin in 53 (16.25%) cases, breast cancer in 67 (20.5%) cases, prostate cancer in 59 (18%) cases, myeloma in 24 (7.4%) cases, and lung cancer in 23 (7.1%) cases. Conclusions The data obtained in this analysis delivers an updated standpoint on Mexico, providing the opportunity to distinguish the current data from global references. Collecting more epidemiological information for better recording of cancer and its associated complications, as well as further studies on them, is necessary.

Enhancing palliative care in vulnerable patients: Robot-assisted radiofrequency ablation for multiple spinal metastases - Technical insights and preliminary outcomes

Background

Radiofrequency thermal ablation (RFA) coupled with vertebroplasty or kyphoplasty offers a minimally invasive, safe, and efficacious approach to palliate polymetastatic spine disease, particularly in medically fragile individuals. However, the application of robotic assistance to RFA for spinal metastases remains unexplored. This study elucidates the technical viability of robot-assisted RFA combined with vertebroplasty in patients afflicted by multiple spinal metastases and presents preliminary outcomes. An illustrative case was also presented.

Materials and Methods

Ten patients aged over 65 years with multiple vertebral metastases were enrolled in this study. Preoperatively, patients exhibited a median Visual Analog Scale (VAS) pain score of 6 and a Median Oswestry Disability Index (ODI) score of 58%. From February 2021 to April 2022, all patients underwent RFA, followed by vertebroplasty for spinal metastases. Surgical procedures were executed using the ExcelsiusGPS® robotic platform.

Results

Patients experienced substantial pain relief, with a median VAS score of 2.5 at 24 h postoperatively (Δ --3.5; P < 0.001) and a median VAS score of 2 at 1 month postoperatively (Δ -4; P < 0.001). All patients were discharged on the first postoperative day and continued their oncological treatments. In addition, the median ODI score at 1 month postoperatively was 34% (Δ --24%; P = 0.006), indicating an enhanced quality of life and a satisfactory impact on daily activities. No procedural or postoperative complications were documented.

Conclusions

This case series represents the inaugural successful application of robot-assisted RFA in conjunction with concurrent vertebroplasty/kyphoplasty. Our preliminary experience demonstrates that patients with oligo- and polymetastatic conditions can derive benefits from this minimally invasive intervention, characterized by rapid postoperative recovery and effective short- to medium-term pain management, without encountering complications.

Evaluation of computed tomography artefacts of carbon-fiber and titanium implants in patients with spinal oligometastatic disease undergoing stereotactic ablative radiotherapy

This study evaluated artefacts on computed tomography (CT) images using Hounsfield units (HU) in patients with spinal oligometastatic disease who received carbon-fiber (CF; n = 11) or titanium (n = 11) spine implants and underwent stereotactic ablative radiotherapy (SABR). Pre- and postoperative HU were measured at the vertebral body, pedicle, and spinal cord at three different levels: the lower instrumented vertebra, the level of metastatic spinal cord compression, and an uninvolved level. Areas measured at each level were delicately matched pre- and postoperatively. Significant differences in HU were observed at the vertebral body, the pedicle, and the spinal cord at the lowest instrumented vertebra level for both CF and titanium (average increase 1.54-fold and 5.11-fold respectively). At the metastatic spinal cord compression level, a trend towards a higher HU-increase was observed in titanium compared with CF treated patients (average increase 2.51-fold and 1.43-fold respectively). The relatively high postoperative HU-increase after insertion of titanium implants indicated CT artefacts, while the relatively low HU-increase of CF implants was not associated with artefacts. Less CT artefacts could facilitate an easier contouring phase in radiotherapy planning. In addition, we propose a CT artefact grading system based on postoperative HU-increase. This system could serve as a valuable tool in future research to assess if less CT artefacts lead to time savings during radiotherapy treatment planning and, potentially, to better tumoricidal effects and less adverse effects if particle therapy would be administered.

Quality of life and its selected determinants in the group of patients with surgically treated spinal tumors

Introduction

Spinal metastases are a common manifestation of advanced neoplastic disease. Destructive neoplastic lesions within the axial skeleton cause unrelieved pain and nervous system disorders involving spinal stenosis and other neural structures. The development of new systemic therapies, radiotherapy and minimally invasive spinal surgeries has increased patients' quality of life by minimising pain and neurological disorders due to vertebral neoplastic infiltration. The aim of the study was to assess the patients' quality of life before and after spine stabilisation surgery with spinal cord decompression to relieve the pressure associated with neoplastic destruction.

Materials and Methods

The study involved 115 subjects with spinal metastases in the preoperative period and 3-4 months after the surgery based on the inclusion criteria (metastatic spinal tumour, sensorimotor dysfunction). The data were collected using the following tools: the Rotterdam Symptom Checklist (RSCL-Rotterdam Symptom Checklist), Acceptance Illness Scale (AIS scale), Activities of Daily Living Scale (ADL scale) and Visual Analogue Scale (VAS). The correlation coefficient was calculated using Spearman's rho assuming the significance level at α = 0.05 (p<0.05).

Results

A higher quality of life was found after surgery (p<0.001) in terms of experiencing physical symptoms (30.7 ± 11.96 points before surgery vs. 20.91 ± 13.00 points after surgery) and psychological symptoms (43.98 ± 14.82 points before surgery vs. 31.35 ± 14.86 points after surgery). The activity level of the subjects also improved (p<0.001; 36.56 ± 22.43 points to 43.55 ± 20.40 points). The level of disease acceptance in the study group was higher after the surgery compared to the preoperative assessment. The subjects with a high level of disease acceptance presented a higher quality of life postoperatively. The independence of the subjects in performing everyday activities after the operation influenced the quality of life, in terms of somatic symptoms (p=0.006), mental symptoms (p=0.001) and activity (p<0.001). Along with the improvement in functional capacity, the quality of life in terms of symptoms and activity levels increased.

Conclusion

The study showed that spinal cord decompression surgery improves the quality of life of patients by reducing neurological dysfunction, increasing the acceptance of the disease and the ability to perform activities of daily living (ADL). Sociodemographic variables did not affect the quality of life of the respondents.

A novel scoring system incorporating sarcopenia to predict postoperative survival in spinal metastasis

BACKGROUND CONTEXT

As the prevalence of spinal metastasis rises, methods to predict survival will become increasingly important for clinical decision-making. Sarcopenia may be used to predict survival in these patients.

PURPOSE

The purpose of this study to develop a prediction model incorporating sarcopenia for postoperative survival in patients with spinal metastasis.

DESIGN

Retrospective cohort study.

PATIENT SAMPLE

This study included 200 patients who underwent operative intervention for spinal metastasis in our institution, a tertiary, academic spine center.

OUTCOME MEASURES

The primary outcome measure was 1-year postoperative survival. The secondary outcome measures were 3-month and 6-month postoperative survival.

METHODS

Clinicopathological and survivorship data was collated. Sarcopenia was defined using the L3 Psoas/Vertebral Body Ratio on cross-sectional CT. Independent predictors of postoperative survival were assessed by multiple logistic regression.

RESULTS

Overall 1-year postoperative survival was 50%. L3/Psoas ratio ≥1.5 (OR 6.2), albumin ≥35g/l (OR 3.0) and primary tumor type were found to be independent predictors of 3 month, 6 month and 1 year postoperative survival on multivariable analysis. Age at surgery, ambulatory status and mode of presentation were not independent predictors of survival. Variables were used to generate a new scoring system, ProgMets, to predict postoperative survival. The ProgMets system had greater correlation and higher area under the curve (AUC, 0.80) for 1-year survival than other scoring systems.

CONCLUSIONS

This is the first model to incorporate sarcopenia to predict survival in spinal metastasis patients and has good prediction of survival compared to previous models. This tool may be increasingly useful for informed decision making for patients and surgeons.

Management of Spinal Metastasis by Minimally Invasive Surgical Techniques: Surgical Principles and Indications-A Literature Review

BACKGROUND

Spinal metastasis is becoming more frequent. This raises the topics of pain and neurological complications, which worsen the functional and survival prognosis of oncological population patients. Surgical treatment must be as complete as possible in order to decompress and stabilize without delaying the management of the oncological disease. Minimally invasive spine surgical techniques inflict less damage on the musculocutaneous plan than opened ones.

METHODS

Different minimally invasive techniques are proposed in this paper for the management of spinal metastasis. We used our experience, developed degenerative and traumatic pathologies, and referred to many authors, establishing a narrative review of our local practice.

RESULTS

Forty-eight articles were selected, and these allowed us to describe the different techniques: percutaneous methods such as vertebro/kyphoplasty, osteosynthesis, mini-open surgery, or that through a posterior or anterior approach. Also, some studies detail the contribution of new technologies, such as intraoperative CT scan and robotic assistance.

CONCLUSIONS

It seems essential to offer a lasting solution to a spinal problem, such as in the form of pain relief, stabilization, and decompression. Our department has embraced a multidisciplinary and multidimensional approach to MISS, incorporating cutting-edge technologies and evidence-based practices.

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

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

Establishing the Swiss Spinal Tumor Registry (Swiss-STR): a prospective observation of surgical treatment patterns and long-term outcomes in patients with primary and metastatic spinal tumors

Background

Tumors of the vertebral column consist of primary spinal tumors and malignancies metastasizing to the spine. Although primary spine tumors are rare, metastases to the spine have gradually increased over past decades because of aging populations and improved survival for various cancer subtypes achieved by advances in cancer therapy. Metastases to the vertebral column occur in up to 70% of cancer patients, with 10% of patients demonstrating epidural spinal cord compression. Therefore, many cancer patients may face spinal surgical intervention during their chronic illness; such interventions range from simple cement augmentation over decompression of neural elements to extended instrumentation or spinal reconstruction. However, precise surgical treatment guidelines do not exist, likely due to the lack of robust, long-term clinical outcomes data and the overall heterogeneous nature of spinal tumors. Objectives of launching the Swiss Spinal Tumor Registry (Swiss-STR) are to collect and analyze high-quality, prospective, observational data on treatment patterns, clinical outcomes, and health-related quality of life (HRQoL) in adult patients undergoing spinal tumor surgery. This narrative review discusses our rationale and process of establishing this spinal cancer registry.

Methods

A REDCap-based registry was created for the standardized collection of clinical, radiographic, surgical, histological, radio-oncologial and oncological variables, as well as patient-reported outcome measures (PROMs).

Discussion

We propose that the Swiss-STR will inform on the effectiveness of current practices in spinal oncology and their impact on patient outcomes. Furthermore, the registry will enable better categorization of the various clinical presentations of spinal tumors, thereby facilitating treatment recommendations, defining the socio-economic burden on the healthcare system, and improving the quality of care. In cases of rare tumors, the multi-center data pooling will fill significant data gaps to yield better understanding of these entities. Finally, our two-step approach first implements a high-quality registry with efficient electronic data capture strategies across hospital sites in Switzerland, and second follows with potential to expand internationally, thus fostering future international scientific collaboration to further push the envelope in cancer research.

Indications and Limits of Surgery for Spinal Metastases Derived from Lung Cancer: A Single-Center Experience

Lung cancer is the second most frequently diagnosed cancer in the world, and surgery is an integral part of the treatment for spinal metastases. The aims of this retrospective study were to assess the overall survival of surgically treated patients affected by lung cancer spinal metastases and identify any factors related to a better survival rate. We recruited 56 consecutive patients (34 male and 22 female) surgically treated for metastatic lung cancer in the spine from 2009 to 2019. Surgical indications were based on a previously published and validated flow chart following a multidisciplinary evaluation. We assessed the localization of vertebral metastases, the presence of other bone or visceral metastases, neurological status according to the Frankel score, ambulatory autonomy, and general status, measured with the Karnofsky performance scale. The expected prognosis was retrospectively assessed according to the revised Tokuhashi score. The median survival was 8.1 months, with over a third of patients surviving more than 1 year. We observed a global improvement in all clinical parameters after surgical treatment. The Tokuhashi predictive score did not correlate with survival after surgery. The results of this study suggest that the surgical treatment of symptomatic spinal metastases from lung cancer can improve quality of life, even in patients with a shorter life expectancy, by controlling pain and improving autonomy.

Metastasis of spine from adenoid cystic carcinoma of the parotid gland: two case reports

BACKGROUND

Spinal metastasis from adenoid cystic carcinoma of the salivary gland is extremely rare. We present two interesting cases of spinal metastasis from adenoid cystic carcinoma of the parotid gland. A 29-year-old Persian male and a 48-year-old Persian female presented with parotid gland mass. The two patients received parotidectomy and radiotherapy. The pathological examination result was adenoid cystic carcinoma. Because of intractable back pain, patients were referred to the hospital after 7 years and 9 months, respectively. Both cases underwent spinal surgery. Histopathology confirmed spinal metastasis from adenoid cystic carcinoma of the parotid gland (case 1: T6, T12, and L1; case 2: T12). Anterior corpectomy of T12 and lateral screw fixation at T11 and L1 were done in case 2. Posterior spinal fusions from T2 to L3 and from T10 to L2 were performed in case 1 and case 2, respectively. Both patients showed good clinical improvement. The last follow-up (case 1: 24 months; case 2: 6 months after surgery), plain radiographs and computed tomography scan showed good fusion without instrumental failure and magnetic resonance imaging revealed good decompression of the spinal cord of both cases.

CONCLUSION

Although spinal metastasis from adenoid cystic carcinoma of the parotid gland is extremely rare, it is necessary to be careful in the differential diagnosis.

Predictive factors for respiratory failure and in-hospital mortality after surgery for spinal metastasis

PURPOSE

Spinal metastasis surgeries carry substantial risk of complications. PRF is among complications that significantly increase mortality rate and length of hospital stay. The risk factor of PRF after spinal metastasis surgery has not been investigated. This study aims to identify the predictors of postoperative respiratory failure (PRF) and in-hospital death after spinal metastasis surgery.

METHODS

We retrospectively reviewed consecutive patients with spinal metastasis surgically treated between 2008 and 2018. PRF was defined as mechanical ventilator dependence > 48 h postoperatively (MVD) or unplanned postoperative intubation (UPI). Collected data include demographics, laboratory data, radiographic and operative data, and postoperative complications. Stepwise logistic regression analysis was used to determine predictors independently associated with PRFs and in-hospital death.

RESULTS

This study included 236 patients (average age 57 ± 14 years, 126 males). MVD and UPI occurred in 13 (5.5%) patients and 13 (5.5%) patients, respectively. During admission, 14 (5.9%) patients had died postoperatively. Multivariate logistic regression analysis revealed significant predictors of MVD included intraoperative blood loss > 2000 mL (odds ratio [OR] 12.28, 95% confidence interval [CI] 2.88-52.36), surgery involving cervical spine (OR 9.58, 95% CI 1.94-47.25), and ASA classification ≥ 4 (OR 6.59, 95% CI 1.85-23.42). The predictive factors of UPI included postoperative sepsis (OR 20.48, 95% CI 3.47-120.86), central nervous system (CNS) metastasis (OR 10.21, 95% CI 1.42-73.18), lung metastasis (OR 7.18, 95% CI 1.09-47.4), and postoperative pulmonary complications (OR 6.85, 95% CI 1.44-32.52). The predictive factors of in-hospital death included postoperative sepsis (OR 13.15, 95% CI 2.92-59.26), CNS metastasis (OR 10.55, 95% CI 1.54-72.05), and postoperative pulmonary complications (OR 9.87, 95% CI 2.35-41.45).

CONCLUSION

PRFs and in-hospital death are not uncommon after spinal metastasis surgery. Predictive factors for PRFs included preoperative comorbidities, intraoperative massive blood loss, and postoperative complications. Identification of risk factors may help guide therapeutic decision-making and patient counseling.

Personalization of Radiation Therapy in the Primary Treatment of Malignant Epidural Spinal Cord Compression (MESCC)

"True" malignant epidural spinal cord compression (MESCC) is used here to describe a lesion compressing of infiltrating the spinal cord associated with neurologic deficits. Radiotherapy alone is the most common treatment, for which several dose-fractionation regimens are available including single-fraction, short-course and longer-course regimens. Since these regimens are similarly effective regarding functional outcomes, patients with poor survival are optimally treated with short-course or even single-fraction radiotherapy. Longer-course radiotherapy results in better local control of malignant epidural spinal cord compression. Since most in-field recurrences occur 6 months or later, local control is particularly important for longer-term survivors who, therefore, should receive longer-course radiotherapy. It is important to estimate survival prior to treatment, which is facilitated by scoring tools. Radiotherapy should be supplemented by corticosteroids, if safely possible. Bisphosphonates and RANK-ligand inhibitors may improve local control. Selected patients can benefit from upfront decompressive surgery. Identification of these patients is facilitated by prognostic instruments considering degree of compression, myelopathy, radio-sensitivity, spinal stability, post-treatment ambulatory status, and patients' performance status and survival prognoses. Many factors including patients' preferences must be considered when designing personalized treatment regimens.

Spine Metastasis: Patients With Poor Performance Status (ECOG) Could benefit From Palliative Surgical Care! A Prospective Cohort Study

STUDY DESIGN

This study used a French prospective national multi-center database of patients with spine metastasis (SpM).

OBJECTIVE

The main challenge was to clarify if SpM patients presenting poor ECOG-PS could benefit from a surgical intervention.

BACKGROUND

Spine metastases (SpM) are debilitating lesions commonly found in the evolution of cancer. At present, patients with poor ECOG-PS do not benefit from surgical care.

MATERIALS AND METHODS

Between 2014 and 2017, 176 SpM patients with poor initial ECOG-PS (3 or 4) were identified.

RESULTS

The median overall survival of patients was 2.1 months (SD 0.2). Seventy-one patients (40.3%) underwent surgery: for 49 patients (27.8%) the intervention consisted of a simple decompression and for 22 patients (12.5%) the previous was associated with an osteosynthesis. Patients who underwent surgery demonstrated significantly longer median overall survival than those who did not: 3.5 months (SD 0.4) versus 1.6 (SD 0.2) ( P <0.0001). No significant differences between operated/nonoperated patients were noted concerning median age (66.4 vs. 64.2 y, P =0.897), the median number of SpM (4.1 vs. 4.2, P =0.374), ECOG-PS 4 ratio (41.6 vs. 39.3%, P =0.616), or for primary tumors ( P =0.103). Patients who underwent surgery statistically improved their neurological impairment according to the Frankel score: 5/11 (45.4%) from A to C, 5/17 (29.4%) from B to C or D, 6/11 (54.5%) from C to D and 2/4 (50%). Twelve patients (16.9%) presented a postoperative complication.

CONCLUSION

Patients with poor ECOG-PS could benefit from surgery. Even though survival gain is small, it permits the preservation of their neurological function. By making ambulation possible, pain is decreased during the last months of their lives.

Preoperative Embolization of Metastatic Spinal Cord Compression with n-Butyl Cyanoacrylate: Safety and Effectiveness in Limiting Blood Loss

PURPOSE

To evaluate the safety and effectiveness of preoperative embolization with n-butyl cyanoacrylate (nBCA) performed for metastatic spinal cord compression (MSCC) in limiting blood loss (BL).

MATERIALS AND METHODS

In this institutional review board-approved retrospective study, clinical records from 2017 to 2022 were reviewed. Twenty consecutive patients (11 men and 9 women; mean age, 65.8 years ± 10.0; range, 45-82 years) underwent 21 preoperative spine tumor embolizations with nBCA. Angiograms were used to calculate the percentage reduction in tumor vascularity, and relevant clinical data (levels studied and embolized, fluoroscopy time [FT], reference dose [RD], and Kerma area product [KAP]) and operative data (BL and operative time [OT]) were analyzed. Adverse events and outcomes were recorded.

RESULTS

A median of 2 levels were embolized per procedure (range, 1-5) but 4.9 were studied (range, 1-10). After embolization, tumor blush was reduced by a median of 87.3% (range, 50%-90%). The mean FT was 41 minutes ± 15.4 (range, 16-67 minutes), the mean RD was 1,977.1 mGy ± 1,794.3 (range, 450.2-6,319 mGy), and the mean KAP was 180.5 Gy·cm² ± 166.2 (range, 30.4-504 Gy·cm²). The adverse event rate was 1 (4.7%) of the 21 embolizations because a weakness of lower extremities related to swelling was observed. Surgery was performed at a mean of 1.4 days ± 1 (range, 1-5 days) after embolization. The mean surgical estimated BL was 432.5 mL ± 328.5 (range, 25-1,100 mL), and the mean OT was 210.1 minutes ± 97.4 (range, 57-489 minutes).

CONCLUSIONS

Preoperative embolization of tumors resected for MSCC with nBCA is a safe procedure allowing for performance of surgery with acceptable BL.

Assessing long-term locoregional control of spinal osseous metastases after microwave ablation

Osseous metastases to the spine result in significant pain and decreased quality of life. The purpose of this study was to evaluate the long-term efficacy of microwave ablation (MWA) for the treatment of spinal metastases regarding pain reduction and local control of disease progression. In this single center retrospective study, patients with osseous metastases to the spine undergoing MWA with vertebroplasty from 2013 to 2020 were included. Locoregional control of metabolic activity at the treated level was assessed using PET/CT scan both pre- and post-procedure. Pain reduction was measured using change in visual analog scale (VAS) pain score. Forty-eight spinal levels were treated with MWA in 28 patients (57 % male, mean age 68 ± 9 years). Median ablation time, energy, and temperature were 4 min and 13 s, 3.6 kJ, and 80 °C, respectively. Median pre-procedure maximum standard uptake value (SUVmax) was significantly reduced following ablation, from 4.55 (IQR 3.65-6.1) to 0 (IQR 0-1.8; p < 0.001), over an average of 29 ± 14.1 month follow up period. Pre-procedure VAS pain score was reduced from median (IQR) of 8 (6.5-9) to 1(1-2), 2(1-3) and 1(0.5-3) at 24 h, four weeks, and six months post-procedure, respectively (all p < 0.001 with respect to pre-procedure scores). In conclusion, this study supports microwave ablation as an effective technique for pain palliation and long-term locoregional tumor control of oligometastatic spinal disease as assessed by metabolic response.

Prolonged durability of extensive contiguous spinal metastasis stabilization in non-small cell lung cancer patients receiving targeted therapy: two case reports and a literature review

Contiguous spinal metastasis poses a challenge for spine surgeons. In patients with a short remaining life expectancy, surgery may be discouraged. However, in select cases, surgery may be inevitable to eliminate pain and improve the patient’s quality of life. Additionally, with advancements in systemic cancer therapy, the efficacy and duration of tumor control have improved significantly. Consequently, a patient’s life expectancy may be difficult to estimate with existing prognostic scores. Because patients may achieve prolonged survival, spinal metastasis surgery could greatly benefit a patient’s quality of life. In this report, we present the details of two patients with non-small lung cancer with contiguous spinal metastasis who underwent spinal surgery for their metastatic disease. After surgery and targeted therapy with epidermal growth factor tyrosine kinase inhibitors (EGFR TKI), the patients attained substantial healing of their previously lytic spines and achieved prolonged survival of up to 42 months. With modern systemic therapy for lung cancer, the treatment of spinal metastatic disease can achieve decent outcomes, even in poor surgical candidates.

A preliminary safety assessment of vertebral augmentation with 32P brachytherapy bone cement

Comprehensive treatment for vertebral metastatic lesions commonly involves vertebral augmentation (vertebroplasty or kyphoplasty) to relieve pain and stabilize the spine followed by multiple sessions of radiotherapy. We propose to combine vertebral augmentation and radiotherapy into a single treatment by adding 32P, a β-emitting radionuclide, to bone cement, thereby enabling spinal brachytherapy to be performed without irradiating the spinal cord. The goal of this study was to address key dosimetry and safety questions prior to performing extensive animal studies. The 32P was in the form of hydroxyapatite powder activated by neutron bombardment in a nuclear reactor. We performed ex vivo dosimetry experiments to establish criteria for safe placement of the cement within the sheep vertebral body. In an in vivo study, we treated three control ewes and three experimental ewes with brachytherapy cement containing 2.23–3.03 mCi 32P ml−1 to identify the preferred surgical approach, to determine if 32P leaches from the cement and into the blood, urine, or feces, and to identify unexpected adverse effects. Our ex vivo experiments showed that cement with 4 mCi 32P ml−1 could be safely implanted in the vertebral body if the cement surface is at least 4 mm from the spinal cord in sheep and 5 mm from the spinal cord in humans. In vivo, a lateral retroperitoneal surgical approach, ventral to the transverse processes, was identified as easy to perform while allowing a safe distance to the spinal cord. The blood, urine, and feces of the sheep did not contain detectable levels of 32P, and the sheep did not experience any neurologic or other adverse effects from the brachytherapy cement. These results demonstrate, on a preliminary level, the relative safety of this brachytherapy cement and support additional development and testing.

Pancreatic Cancer Metastasis to the Spine: A Systematic Review of Management Strategies and Outcomes with Case Illustration

OBJECTIVE

We aim to provide a thorough review of the literature regarding patient characteristics, treatment options, and outcomes of pancreatic cancer metastasis to the spine. We also provide an illustrative case from our institution of a patients with pancreatic adenocarcinoma presenting initially as cervical radiculopathy with an isolated cervical spine lesion.

METHODS

Using the PRISMA guidelines, the literature in PubMed, Google Scholar, and Web of Science databases was searched. We excluded systematic reviews and meta-analyses that did not provide novel cases, as well as reports of metastatic disease from other nonpancreatic primary cancers.

RESULTS

Thirty-two patients across 21 studies met the inclusion criteria. The patients were predominantly male (58%), with a mean age of 59 years. Of patients, 64% presented with back pain, 39% with motor deficits, and 15% with bladder or bowel dysfunction. For treatment, chemotherapy was used in 55% of cases and radiotherapy in 42%. Surgical treatment was performed in 42% of cases, with complete tumor resection achieved in 24% of cases. The mean patient survival after treatment was 28 weeks (range, 1-83 weeks), with patients undergoing treatment involving surgery having increased survival (44 weeks) compared with noninvasive treatment alone (18 weeks).

CONCLUSIONS

Spinal metastasis of pancreatic cancer is rare and typically portends a poor prognosis. It is vital to recognize the presence of spinal involvement early in the disease course and initiate treatment.

JAK/STAT Signaling: Molecular Targets, Therapeutic Opportunities, and Limitations of Targeted Inhibitions in Solid Malignancies

JAK/STAT signaling pathway is one of the important regulatory signaling cascades for the myriad of cellular processes initiated by various types of ligands such as growth factors, hormones, and cytokines. The physiological processes regulated by JAK/STAT signaling are immune regulation, cell proliferation, cell survival, apoptosis and hematopoiesis of myeloid and non-myeloid cells. Dysregulation of JAK/STAT signaling is reported in various immunological disorders, hematological and other solid malignancies through various oncogenic activation mutations in receptors, downstream mediators, and associated transcriptional factors such as STATs. STATs typically have a dual role when explored in the context of cancer. While several members of the STAT family are involved in malignancies, however, a few members which include STAT3 and STAT5 are linked to tumor initiation and progression. Other STAT members such as STAT1 and STAT2 are pivotal for antitumor defense and maintenance of an effective and long-term immune response through evolutionarily conserved programs. The effects of JAK/STAT signaling and the persistent activation of STATs in tumor cell survival; proliferation and invasion have made the JAK/STAT pathway an ideal target for drug development and cancer therapy. Therefore, understanding the intricate JAK/STAT signaling in the pathogenesis of solid malignancies needs extensive research. A better understanding of the functionally redundant roles of JAKs and STATs may provide a rationale for improving existing cancer therapies which have deleterious effects on normal cells and to identifying novel targets for therapeutic intervention in solid malignancies.

Quality of Life Changes After Surgery for Metastatic Spinal Disease: A Systematic Review and Meta-analysis

STUDY DESIGN

This was a systematic review and meta-analysis.

OBJECTIVE

A systematic review and meta-analysis was conducted to assess the quality of life (QoL) after open surgery for spinal metastases, and how surgery affects physical, social/family, emotional, and functional well-being.

SUMMARY OF BACKGROUND DATA

It remains questionable to what extent open surgery improves QoL for metastatic spinal disease, it would be interesting to quantify the magnitude and duration of QoL benefits-if any-after surgery for spinal metastases.

MATERIALS AND METHODS

Included were studies measuring QoL before and after nonpercutaneous, open surgery for spinal metastases for various indications including pain, spinal cord compression, instability, or tumor control. A random-effect model assessed standardized mean differences (SMDs) of summary QoL scores between baseline and 1, 3, 6, or 9-12 months after surgery.

RESULTS

The review yielded 10 studies for data extraction. The pooled QoL summary score improved from baseline to 1 month (SMD=1.09, P<0.001), to 3 months (SMD=1.28, P<0.001), to 6 months (SMD=1.21, P<0.001), and to 9-12 months (SMD=1.08, P=0.001). The surgery improved physical well-being during the first 3 months (SMD=0.94, P=0.022), improved emotional (SMD=1.19, P=0.004), and functional well-being (SMD=1.08, P=0.005) during the first 6 months, and only improved social/family well-being at month 6 (SMD=0.28, P=0.001).

CONCLUSIONS

The surgery improved QoL for patients with spinal metastases, and rapidly improved physical, emotional, and functional well-being; it had minimal effect on social/family well-being. However, choosing the optimal candidate for surgical intervention in the setting of spinal metastases remains paramount: otherwise postoperative morbidity and complications may outbalance the intended benefits of surgery. Future research should report clear definitions of selection criteria and surgical indication and provide stratified QoL results by indication and clinical characteristics such as primary tumor type, preoperative Karnofsky, and Bilsky scores to elucidate the optimal candidate for surgical intervention.

Recent advances and new discoveries in the pipeline of the treatment of primary spinal tumors and spinal metastases: a scoping review of registered clinical studies from 2000 to 2020

The field of spinal oncology has substantially evolved over the past decades. This review synthesizes and appraises what was learned and what will potentially be discovered from the recently completed and ongoing clinical studies related to the treatment of primary and secondary spinal neoplasms. This scoping review included all clinical studies on the treatment of spinal neoplasms registered in the ClinicalTrials.gov website from February 2000 to December 2020. The terms "spinal cord tumor," "spinal metastasis," and "metastatic spinal cord compression" were used. Of the 174 registered clinical studies on primary spinal tumors and spinal metastasis, most of the clinical studies registered in this American registry were interventional studies led by single institutions in North America (n = 101), Europe (n = 43), Asia (n = 24), or other continents (n = 6). The registered clinical studies mainly focused on treatment strategies for spinal neoplasms (90.2%) that included investigating stereotactic radiosurgery (n = 33), radiotherapy (n = 21), chemotherapy (n = 20), and surgical technique (n = 11). Of the 69 completed studies, the results from 44 studies were published in the literature. In conclusion, this review highlights the key features of the 174 clinical studies on spinal neoplasms that were registered from 2000 to 2020. Clinical trials were heavily skewed toward the metastatic population as opposed to the primary tumors which likely reflects the rarity of the latter condition and associated challenges in undertaking prospective clinical studies in this population. This review serves to emphasize the need for a focused approach to enhancing translational research in spinal neoplasms with a particular emphasis on primary tumors.

Monitoring spinal surgery for extramedullary tumors and fractures

Meningiomas are the most common intradural extramedullary tumors, followed by nerve sheath tumors that can also grow extradurally. Metastases are the most frequent extradural tumors and most commonly affect the thoracic vertebrae. Spinal fractures with column dislocation and/or instability require surgical fixation. Spine surgery for an extramedullary tumor or fracture usually involves decompression of neural elements and instrumentation for stabilization. These procedures risk spinal cord and nerve root injury. The incidence of nerve root deficits after resection of nerve sheath tumors is particularly high since the tumor grows from the rootlets. Intraoperative neurophysiologic monitoring and mapping techniques have been introduced to prevent iatrogenic neurologic deficits. These include motor and sensory evoked potentials, electromyography, compound muscle action potentials, and the bulbocavernosus reflex. The combination of techniques chosen for a particular procedure depends on the surgical level and the character of the lesion.

Purposeful irradiation of the epidural space to enhance local control without compromising cord sparing in spine radiosurgery†

Purpose

The epidural space is a frequent site of cancer recurrence after spine stereotactic radiosurgery (SSRS). This may be due to microscopic disease in the epidural space which is underdosed to obey strict spinal cord dose constraints. We hypothesized that the epidural space could be purposefully irradiated to prescription dose levels, potentially reducing the risk of recurrence in the epidural space without increasing toxicity.

Methods and materials

SSRS clinical treatment plans with spinal cord contours, spinal planning target volumes (PTV_spine), and delivered dose distributions were retrospectively identified. An epidural space PTV (PTV_epidural) was contoured to avoid the spinal cord and focus on regions near the PTV_spine. Clinical plan constraints included PTV_spine constraints (D_95% and D_5%, based on prescription dose) and spinal cord constraints (D_max < 1300 cGy, D10% < 1000 cGy). Plans were revised with three prescriptions of 1800, 2000 and 2400 cGy in two sets, with one set of revisions (supplemented plans) designed to additionally target the PTV_epidural by optimizing PTV_epidural D_95% in addition to meeting every clinical plan constraint. Clinical and revised plans were compared according to their PTV_epidural DVH distributions, and D_95% distributions.

Results

Seventeen SSRS plans meeting the above criteria were identified. Supplemented plans had higher doses to the epidural low-dose regions at all prescription levels. Epidural PTV D_95% values for the supplemented plans were all statistically significantly different from the values of the base plans (p < 10^-4). The epidural PTV D_95% increases depended on the initial prescription, increasing from 11.52 to 16.90 Gy, 12.23 to 18.85 Gy, and 13.87 to 19.54 Gy for target prescriptions of 1800, 2000 and 2400 cGy, respectively.

Conclusions

Purposefully targeting the epidural space in SSRS may increase control in the epidural space without significantly increasing the risk of spinal cord toxicity. A clinical trial of this approach should be considered.

National trends in the surgical management of metastatic lung cancer to the spine using the national inpatient sample database from 2005 to 2014

Optimal management of metastatic lung cancer to the spine (MLCS) incorporates a multidisciplinary approach. With improvements in lung cancer screening andnonsurgical treatment, the role for surgerymay be affected. The objective of this study is to assess trends in the surgical management of MLCS using the National Inpatient Sample (NIS) database. The NIS was queried for patients with MLCS who underwent surgery from 2005 to 2014. The frequencies of spinal decompression alone, spinal stabilization with or without (+/-) decompression, and vertebral augmentation were calculated. Statistical analysis was performed to analyze the effect of patient characteristics on outcomes. The most common procedure performed was vertebral augmentation (10719, 44.3%), followed by spinal stabilization +/- decompression (8634, 35.7%) and then decompression alone (4824, 20.0%). The total number of surgeries remained stable, while the rate of spinal stabilizations increased throughout the study period (p < 0.001). Invasive procedures such as stabilization and decompression were associated with greater costs, length of stay,complications and mortality. Increasingcomorbidity was associated with increased odds of complication, especially in patients undergoing more invasive procedures. In patients with lowpre-operative comorbidity, the type of procedure did not influence the odds of complication. Graded increases in length of stay, cost and mortality were seen with increasing complication rate.The rate of spinal stabilizations increased, which may be due to either increased early detection of disease facilitating use of outpatient vertebral augmentation procedures and/or the recognition that surgical decompression and stabilization are necessary for optimal outcome in the setting of MLCS with neurological deficit.

Spinal metastasis: The rise of minimally invasive surgery

INTRODUCTION

Bone is the third most common site of metastatic cancer, of which the spine is the most frequently involved. As metastatic cancer prevalence rises and surgical techniques advance, operative intervention for spinal metastases is expected to rise. In the first operative cohort of spinal metastasis in Ireland, we describe the move towards less invasive surgery, the causative primary types and post-operative survival.

METHODS

This is a retrospective cohort study of all operative interventions for spinal metastasis in a tertiary referral centre over eight years. Primary spinal tumours and local invasion to the spine were excluded. Median follow up was 1895 days.

RESULTS

225 operative procedures in 196 patients with spinal metastasis were performed over eight years. Average cases per year increased form 20 per year to 29 per year. Percutaneous procedures became more common, accounting for the majority (53%) in the final two years. The most common primary types were breast, myeloma, lung, prostate and renal. Overall survival at 1 year was 51%. Primary type was a major determinant of survival, with breast and the haematological cancers demonstrating good survival, while lung had the worst prognosis.

CONCLUSION

This is the first descriptive cohort of operative interventions for spinal metastasis in an Irish context. Surgery for spinal metastasis is performed at an increasing rate, especially through minimally-invasive means. The majority of patients survive for at least one year post-operatively. Prudent resource planning is necessary to prepare for this growing need.

A Web-Based Calculator for Predicting the Occurrence of Wound Complications, Wound Infection, and Unplanned Reoperation for Wound Complications in Patients Undergoing Surgery for Spinal Metastases

BACKGROUND

In the present study, we identified the risk factors for wound complications, wound infection, and reoperation for wound complications after spine metastasis surgery and deployed the resultant model as a web-based calculator.

METHODS

Patients treated at a single comprehensive cancer center during a 7-year period were included. The demographics, pathology, comorbidities, laboratory values, and operative details were collected. Factors with P < 0.15 on univariable regression were entered into multivariable logistic regression to generate predictive models internally validated using 1000 bootstrapped samples.

RESULTS

Of the 330 patients included, 29 (7.6%) had experienced a surgical site infection. The independent predictive factors for wound-related complications were a higher Charlson comorbidity index (CCI; odds ratio [OR], 1.41 per point; P < 0.01), Karnofsky performance scale score ≤70 (OR, 2.14; P = 0.04), lower platelet count (OR, 0.49 per 10⁵/μL; P < 0.01), revision versus index surgery (OR, 3.10; P = 0.02), and increased incision length (OR, 1.21 per level; P = 0.02). Wound infection was associated with a higher CCI (OR, 1.60 per point; P < 0.01), a lower platelet count (OR, 0.35 per 10⁵/μL; P < 0.01), revision surgery (OR, 4.63; P = 0.01), and a longer incision length (OR, 1.25 per level; P = 0.03). Unplanned reoperation for wound complications was predicted by a higher CCI (OR, 1.39 per point; P = 0.003), prior irradiation (OR, 2.52; P = 0.04), a lower platelet count (OR, 0.57 per 10⁵/μL; P = 0.02), and revision surgery (OR, 3.34; P = 0.03), The optimism-corrected areas under the curve were 0.75, 0.81, and 0.72 for the wound complication, infection, and reoperation models, respectively.

CONCLUSIONS

Low platelet counts, poorer health status, more invasive surgery, and revision surgery all independently predicted the risk of wound complications, including infection and unplanned reoperation for infection. Validation of the calculators in a prospective study is merited.

Plastic surgery wound closure following resection of spinal metastases

OBJECTIVE

Surgical site infection and dehiscence are devastating complications of surgery for spinal metastases. Wound closure involving plastic surgeons has been proposed as a strategy to lower post-operative complications. Here we investigated whether plastic surgery closure is associated with lower rates of wound complications, wound infection, and wound reoperation compared to simple closure by spine surgeons.

METHODS

Patients surgically treated for metastatic tumors at a single comprehensive cancer center between April 2013-2020 were retrospectively identified. Primary pathology, demographic information, clinical characteristics, pre-operative laboratory values, tumor location, operative characteristics, and post-operative outcomes were collected. Univariable analyses used student t-tests for continuous variables and χ² tests for categorical variables. Multivariable regressions were performed to control for confounders.

RESULTS

We included 317 patients, of which 56 underwent closure by plastic surgeons and 291 by neurosurgeons. Patients in the plastic surgery cohort were more likely to have received prior radiation to the surgical site, more often on long-term corticosteroid therapy, and more likely to have sacrococcygeal tumors. Operations involving plastic surgeons were more likely to be revision surgeries, corpectomies, and to involve a staged approach. Additionally, patients in the plastic surgery cohort had longer incision lengths, longer surgeries, greater intraoperative blood loss (IOBL), were more likely to receive transfusions, and had longer hospitalizations. Local paraspinous advancement flaps were the most common complex wound closure technique. Plastic surgery closure was not significantly associated with a difference in rates of post-operative wound complications, wound infection, or wound-related reoperations compared to simple wound closure.

CONCLUSION

We identified that patients undergoing plastic surgery wound closure had worse baseline risk, longer surgeries, greater IOBL, and longer hospitalizations compared to patients receiving simple closure. Despite their increased risk, complex wound closure did not significantly alter the rates of post-operative wound complications, wound infection, or wound-related reoperations. Consideration may be given to plastic surgery closure in patients at high risk of wound complications or with extensive wound defects.

The Early Results of Vertebral Pathological Compression Fracture of Extra- nodal Lymphoma with HIV-positive Patients Treated by Percutaneous Kyphoplasty

BACKGROUND

Vertebral pathological compression fracture involving extra-nodal lymphoma impacts negatively on the quality of life of HIV-positive patients. The choice of a safe and effective approach to palliative care in this condition remains a challenge.

OBJECTIVE

The purpose of this study was to investigate the safety and efficacy of percutaneous kyphoplasty (PKP) in the treatment of vertebral pathological compression fracture of extra-nodal lymphoma in HIV-positive patients.

METHODS

A retrospective analysis, from January 2016 to August 2019, was performed on 7 HIVpositive patients, 3 males and 4 females, with extra-nodal lymphoma with a vertebral pathological compression fracture. The patients were treated using percutaneous kyphoplasty in our hospital. Preoperative assessment of the patients was conducted regarding their hematological profile, biochemical indicators, liver and kidney function, blood coagulation function, CD4+T lymphocyte count and viral load. Subsequently, the patients were placed on highly active antiretroviral therapy (HAART) and rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (RCHOP) regimen. Besides, antibiotics, nutritional support and immune-modulating drugs were also administered, rationally. Postoperatively, the height of the anterior edge of the injured vertebrae, Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI) values were evaluated. Patients were also monitored for any complications related to the operation.

RESULTS

The average CD4+T cell count for the patients was 164 (range 114 ~247 / ul), while the viral load was 26,269 (range 5,765 ~82,321 copies/ul). All patients received nutritional and immune support and registered significant improvements in the levels of ALB and Hb (P<0.05). In all cases, the operation was uneventful with neither cement leakage nor toxic reactions observed. Similarly, no opportunistic infections, other complications or deaths were reported. The height of the anterior vertebral body and the ODI score of the injured vertebrae were significantly improved immediately after surgery (P<0.05). Compared to the preoperative VAS (7.71±1.11), postoperative values were significantly reduced immediately after surgery (3.85±0.90) and at 2 weeks, 1 month and 6 months post-surgery: 2.71±0.76, 3.29±1.11, and 4.00±0.82, respectively (P<0.01).

CONCLUSION

Supported with appropriate perioperative treatment measures, PKP is safe and effective in the treatment of pathological vertebral compression fracture due to extra-nodal lymphoma in HIV-positive patients.

Spine Metastasis in Elderly: Encouraging Results for Better Survival

MINI

The incidence of spinal metastasis (SpM) is increasing, and life expectancy for patients with malignancy is also rising. The "elderly" represent a population with steady growth in SpM proportion. Bracing is associated with lower survival. We believe that surgery should be considered, regardless of the patient's age.

Radiotherapy and Surgical Advances in the Treatment of Metastatic Spine Tumors: A Narrative Review

Spine tumors encompass a wide range of diseases with a commensurately broad spectrum of available treatments, ranging from radiation for spinal metastases to highly invasive en bloc resection for primary vertebral column malignancies. This high variability in treatment approaches stems both from variability in the goals of surgery (e.g., oncologic cure vs. symptom palliation) and from the significant advancements in surgical technologies that have been made over the past 2 decades. Among these advancements are improvements in surgical technique, namely minimally invasive approaches, increased availability of focused radiation modalities (e.g., proton therapy and linear accelerator devices), and new surgical technologies, such as carbon fiber-reinforced polyether ether ketone rods. In addition, several groups have described nonsurgical interventions, such as vertebroplasty and kyphoplasty for spinal instability secondary to pathologic fracture, and lesion ablation with spinal laser interstitial thermoablation, radiofrequency ablation, or cryoablation. We provide an overview of the latest technological advancements in spinal oncology and their potential usefulness for modern spinal oncologists.

Factors associated with adjacent-level tumor progression in patients receiving surgery followed by radiosurgery for metastatic epidural spinal cord compression

OBJECTIVE

Separation surgery followed by spine stereotactic radiosurgery (SSRS) has been shown to achieve favorable rates of local tumor control and patient-reported outcomes in patients with metastatic epidural spinal cord compression (MESCC). However, rates and factors associated with adjacent-level tumor progression (ALTP) in this population have not yet been characterized. The present study aimed to identify factors associated with ALTP and examine its association with overall survival (OS) in patients receiving surgery followed by radiosurgery for MESCC.

METHODS

Thirty-nine patients who underwent separation surgery followed by SSRS for MESCC were identified using a prospectively collected database and were retrospectively reviewed. Radiological measurements were collected from preoperative, postoperative, and post-SSRS MRI. Statistical analysis was conducted using the Kaplan-Meier product-limit method and Cox proportional hazards test. Subgroup analysis was conducted for patients who experienced ALTP into the epidural space (ALTP-E).

RESULTS

The authors' cohort included 39 patients with a median OS of 14.7 months (range 2.07-96.3 months). ALTP was observed in 16 patients (41.0%) at a mean of 6.1 ± 5.4 months postradiosurgery, of whom 4 patients (10.3%) experienced ALTP-E. Patients with ALTP had shorter OS (13.0 vs 17.1 months, p = 0.047) compared with those without ALTP. Factors associated with an increased likelihood of ALTP included the amount of bone marrow infiltrated by tumor at the index level, amount of residual epidural disease following separation surgery, and prior receipt of radiotherapy at the index level (p < 0.05). Subgroup analysis revealed that primary tumor type, amount of preoperative epidural disease, time elapsed between surgery and radiosurgery, and prior receipt of radiotherapy at the index level were significantly associated with ALTP-E (p < 0.05).

CONCLUSIONS

To the authors' knowledge, this study is the first to identify possible risk factors for ALTP, and they suggest that it may be associated with shorter OS in patients receiving surgery followed by radiosurgery for MESCC. Future studies with higher power should be conducted to further characterize factors associated with ALTP in this population.

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

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

Predicting nonroutine discharge in patients undergoing surgery for vertebral column tumors

OBJECTIVE

More than 8000 patients are treated annually for vertebral column tumors, of whom roughly two-thirds will be discharged to an inpatient facility (nonroutine discharge). Nonroutine discharge is associated with increased care costs as well as delays in discharge and poorer patient outcomes. In this study, the authors sought to develop a prediction model of nonroutine discharge in the population of vertebral column tumor patients.

METHODS

Patients treated for primary or metastatic vertebral column tumors at a single comprehensive cancer center were identified for inclusion. Data were gathered regarding surgical procedure, patient demographics, insurance status, and medical comorbidities. Frailty was assessed using the modified 5-item Frailty Index (mFI-5) and medical complexity was assessed using the modified Charlson Comorbidity Index (mCCI). Multivariable logistic regression was used to identify independent predictors of nonroutine discharge, and multivariable linear regression was used to identify predictors of prolonged length of stay (LOS). The discharge model was internally validated using 1000 bootstrapped samples.

RESULTS

The authors identified 350 patients (mean age 57.0 ± 13.6 years, 53.1% male, and 67.1% treated for metastatic vs primary disease). Significant predictors of prolonged LOS included higher mCCI score (β = 0.74; p = 0.026), higher serum absolute neutrophil count (β = 0.35; p = 0.001), lower hematocrit (β = -0.34; p = 0.001), use of a staged operation (β = 4.99; p < 0.001), occurrence of postoperative pulmonary embolism (β = 3.93; p = 0.004), and surgical site infection (β = 9.93; p < 0.001). Significant predictors of nonroutine discharge included emergency admission (OR 3.09; p = 0.001), higher mFI-5 score (OR 1.90; p = 0.001), lower serum albumin level (OR 0.43 per g/dL; p < 0.001), and operations with multiple stages (OR 4.10; p < 0.001). The resulting statistical model was deployed as a web-based calculator (https://jhuspine4.shinyapps.io/Nonroutine_Discharge_Tumor/).

CONCLUSIONS

The authors found that nonroutine discharge of patients with surgically treated vertebral column tumors was predicted by emergency admission, increased frailty, lower serum albumin level, and staged surgical procedures. The resulting web-based calculator tool may be useful clinically to aid in discharge planning for spinal oncology patients by preoperatively identifying patients likely to require placement in an inpatient facility postoperatively.

Laser interstitial thermotherapy (LITT) for the treatment of tumors of the brain and spine: a brief review

INTRODUCTION

Laser Interstitial Thermotherapy (LITT; also known as Stereotactic Laser Ablation or SLA), is a minimally invasive treatment modality that has recently gained prominence in the treatment of malignant primary and metastatic brain tumors and radiation necrosis and studies for treatment of spinal metastasis has recently been reported.

METHODS

Here we provide a brief literature review of the various contemporary uses for LITT and their reported outcomes.

RESULTS

Historically, the primary indication for LITT has been for the treatment of recurrent glioblastoma (GBM). However, indications have continued to expand and now include gliomas of different grades, brain metastasis (BM), radiation necrosis (RN), other types of brain tumors as well as spine metastasis. LITT is emerging as a safe, reliable, minimally invasive clinical approach, particularly for deep seated, focal malignant brain tumors and radiation necrosis. The role of LITT for treatment of other types of tumors of the brain and for spine tumors appears to be evolving at a small number of centers. While the technology appears to be safe and increasingly utilized, there have been few prospective clinical trials and most published studies combine different pathologies in the same report.

CONCLUSION

Well-designed prospective trials will be required to firmly establish the role of LITT in the treatment of lesions of the brain and spine.

Can Polyether Ether Ketone Dethrone Titanium as the Choice Implant Material for Metastatic Spine Tumor Surgery?

Instrumentation during metastatic spine tumor surgery (MSTS) provides stability to the spinal column in patients with pathologic fracture or iatrogenic instability produced while undergoing extensive decompression. Titanium is the current implant material of choice in MSTS. However, it hinders radiotherapy planning and generates artifacts, with magnetic resonance imaging and computed tomography scans used for postoperative evaluation of tumor recurrence and/or complications. The high modulus of elasticity of titanium (110 GPa) results in stress shielding, which may lead to construct failure at the bone-implant interface. Polyether ether ketone (PEEK), a thermoplastic polymer, is an emerging alternative to titanium for use in MSTS. The modulus of elasticity of PEEK (3.6 GPa) is close to that of cortical bone (17-21 GPa), resulting in minimal stress shielding. Its radiolucent and nonmetallic properties cause minimal interference with magnetic resonance imaging and computed tomography scans. PEEK also causes low-dose perturbation for radiotherapy planning. However, PEEK has reduced bioactivity with bone and lacks sufficient rigidity to be used as rods in MSTS. The reduced bioactivity of PEEK may be addressed by 1) surface modification (introducing porosity or bioactive coating with hydroxyapatite [HA] or titanium) and 2) forming composites with HA/titanium. The mechanical properties of PEEK may be improved by forming composites with HA or carbon fiber. Despite these modifications, all PEEK and PEEK-based implants are difficult to handle and contour intraoperatively. Our review provides a comprehensive overview of PEEK and modified PEEK implants, with a description of their properties and limitations, potentially serving as a basis for their future development and use in MSTS.

The rise of metastatic bone disease in Ireland

To describe the expected rise of metastatic bone disease in Ireland, the relative primary types, and the locations of spread within the skeleton. This was a population-based epidemiological study using cancer registry data. We included patients with known metastatic cancer to bone, within 1 year of the primary diagnosis, during the years 1994 to 2012 inclusive. Our main outcome measures were age-specific, gender-specific and age-standardised incidence rates of bone metastasis, primary types and metastatic location within the skeleton. There were 14,495 recognised cases of bone metastasis in Ireland, 1994-2012 inclusive. Cases consistently rose over the time period, with 108% case increase and 51% age-standardised incidence rise. Annual percentage change increased across both genders and over all age groups. Most of this rise was not due to demographic population change. Breast, prostate and lung accounted for the majority of primary types. GI cancers were the fourth most common primary type. There were proportional increases in breast and lung, with proportional decreases in prostate. The spine was the major metastatic site. Bone metastasis is a significant and rising healthcare concern in Ireland. This rise is disproportionate to demographic changes. Breast, prostate and lung cancers account for the majority. GI cancers are implicated in an unexpectedly high number of cases. Spine is the most common location of bony metastasis, especially at presentation. Prudent healthcare planning is necessitated to prepare for the growing consequences of bone metastasis in cancer patients.

Minimally Invasive Spine Surgery: Techniques, Technologies, and Indications

Over the past few decades, interest in minimally invasive spine surgery (MISS) has increased tremendously due to its core principle of minimizing approach-related injury while providing outcomes similar to traditional open spine procedures. With technical and technological advancements, MISS has expanded its utility not only to simple spinal stenosis, but also to complex spinal pathologies such as metastasis, trauma, or adult spinal deformity. In this article, we review the techniques and technology in MISS and discuss the indications, benefits, and limitations of MISS.

Strategy for the Practice of Spine Oncological Surgery During the Covid-19 Pandemic

STUDY DESIGN

Case series.

OBJECTIVE

For each of the most frequent clinical scenarios, the authors reached a consensus on how should be timing and indications be optimized to reduce risk while maintaining the expected outcomes under the Covid-19 pandemics.

SUMMARY OF BACKGROUND DATA

The organization of health care has been changed by the Covid-19 pandemic with a direct impact on Spine Oncology Surgery. Emergency surgery is still a priority, but in case of spinal tumors it should be better defined which conditions require emergency treatment.

METHODS

An expert panel with general spine surgeons, oncological spine surgeons, and radiation oncologists was formed to analyze the most frequent scenarios in spinal musculoskeletal oncology during Covid-19 pandemics.

RESULTS

Spine metastases can be found incidentally during follow-up or can clinically occur by increasing pain, pathologic fracture, and/or neurological symptoms. Primary spine tumors are much more rare and very rarely present with acute onset. The first step is to suspect this rare condition, to avoid to treat a primary tumor as it were a metastasis. Most complex surgery, like en bloc resection, associated with high morbidity and mortality rate for the treatment of low grade malignancy like chordoma or chondrosarcomas, if intensive care unit availability is reduced, can be best delayed some weeks, as not impacting on prognosis, due to the slow growth rate of these conditions. The currently accepted protocols for Ewing sarcoma (ES) and osteogenic sarcoma must be performed for local and systemic disease control. For ES, after the first courses of chemotherapy, radiotherapy can be selected instead of surgery, during Covid-19, to the end of the full course of chemotherapy. In immunocompromised patients, (treated by chemotherapy), it is necessary to avoid contact with affected or exposed people.

CONCLUSION

Even more than during normal times, a multidisciplinary approach is mandatory to share the decision to modify a treatment strategy.

LEVEL OF EVIDENCE

5.

Predicting tumor-specific survival in patients with spinal metastatic renal cell carcinoma: which scoring system is most accurate?

OBJECTIVE

Although several prognostic scores for spinal metastatic disease have been developed in the past 2 decades, the applicability and validity of these models to specific cancer types are not yet clear. Most of the data used for model formation are from small population sets and have not been updated or externally validated to assess their performance. Developing predictive models is clinically relevant as prognostic assessment is crucial to optimal decision-making, particularly the decision for or against spine surgery. In this study, the authors investigated the performance of various spinal metastatic disease risk models in predicting prognosis for spine surgery to treat metastatic renal cell carcinoma (RCC).

METHODS

Data of patients who underwent surgery for RCC metastatic to the spine at 2 tertiary centers between 2010 and 2019 were retrospectively retrieved. The authors determined the prognostic value associated with the following scoring systems: the Tomita score, original and revised Tokuhashi scores, original and modified Bauer scores, Katagiri score, the Skeletal Oncology Research Group (SORG) classic algorithm and nomogram, and the New England Spinal Metastasis Score (NESMS). Regression analysis of patient variables in association with 1-year survival after surgery was assessed using Cox proportional hazard models. Calibration and time-dependent discrimination analysis were tested to quantify the accuracy of each scoring system at 3 months, 6 months, and 1 year.

RESULTS

A total of 86 metastatic RCC patients were included (median age 64 years [range 29-84 years]; 63 males [73.26%]). The 1-year survival rate was 72%. The 1-year survival group had a good performance status (Karnofsky Performance Scale [KPS] score 80%-100%) and an albumin level > 3.5 g/dL (p < 0.05). Multivariable-adjusted Cox regression analysis showed that poor performance status (KPS score < 70%), neurological deficit (Frankel grade A-D), and hypoalbuminemia (< 3.5 g/dL) were associated with a higher risk of death before 1 year (p < 0.05). The SORG nomogram, SORG classic, original Tokuhashi, and original Bauer demonstrated fair performance (0.7 < area under the curve < 0.8). The NESMS differentiates survival among the prognostic categories with the highest accuracy (area under the curve > 0.8).

CONCLUSIONS

The present study shows that the most cited and commonly used scoring systems have a fair performance predicting survival for patients undergoing spine surgery for metastatic RCC. The NESMS had the best performance at predicting 1-year survival after surgery.