Diagnosis and management of metastatic spine disease

Robotic assisted surgery for the treatment of spinal metastases: A case series

OBJECTIVE

Spinal metastases can significantly affect quality of life in patients with cancer and present complex neurosurgical challenges for surgeons. Surgery with instrumentation is often indicated to alleviate pain, preserve neurological function, and ensure mechanical stability. However, distortions in the bony anatomy due to oncological disease can decrease the accuracy of pedicle screw placement. Robotic-assisted surgery may offer an opportunity to increase screw accuracy and improve navigation of spinal lesions compared to conventional techniques. Therefore, we presented our institutional experience evaluating robotic-assisted surgical fixation for spinal metastases.

METHODS

Patients undergoing robotic-assisted surgery at a large tertiary care center between January 2019 - January 2023 for the treatment of spinal metastases were identified. Patient characteristics, including demographics, tumor pathology, surgical complications, and post-operative outcomes were extracted. The Gertzbein Robbins classification system (GRS) was used to assess pedicle screw placement accuracy in patients with post-operative computed tomography.

RESULTS

Twenty patients were identified, including 7 females (35 %), with an overall median age of 66 years (range: 39-80 years) and median BMI of 25 kg/m2 (range: 17-34 kg/m2). An average of four spinal levels were instrumented, with metastases located primarily in the thoracic (n=17, 85 %) spine. Common primary tumor types included prostate (n=4), lung (n=2), and plasma cell (n=2) cancers. Most pedicle screws (92 %) were classified as GRS A in patients with postoperative imaging. Post-operative complications were unrelated to the use of the robot, and included pulmonary embolism (n=1), deep vein thrombosis (n=2), and gastric symptoms (n=3). Three patients were readmitted at 30 days, with one reoperation due to tumor recurrence. Four patients were deceased within 6 months of surgery.

CONCLUSIONS

Despite the inherent high-risk nature of these surgeries, this study underscores the safety and efficacy of robotic-assisted surgery in the management of spinal metastases. Robots can be helpful in ensuring accuracy of pedicle screw placement in patients with metastatic disease.

Synchronous versus metachronous spinal metastasis: a comparative study of survival outcomes following neurosurgical treatment

PURPOSE

Patients with spinal metastases (SM) from solid neoplasms typically exhibit progression to an advanced cancer stage. Such metastases can either develop concurrently with an existing cancer diagnosis (termed metachronous SM) or emerge as the initial indication of an undiagnosed malignancy (referred to as synchronous SM). The present study investigates the prognostic implications of synchronous compared to metachronous SM following surgical resection.

METHODS

From 2015 to 2020, a total of 211 individuals underwent surgical intervention for SM at our neuro-oncology facility. We conducted a survival analysis starting from the date of the neurosurgical procedure, comparing those diagnosed with synchronous SM against those with metachronous SM.

RESULTS

The predominant primary tumor types included lung cancer (23%), prostate cancer (21%), and breast cancer (11.3%). Of the participants, 97 (46%) had synchronous SM, while 114 (54%) had metachronous SM. The median overall survival post-surgery for those with synchronous SM was 13.5 months (95% confidence interval (CI) 6.1-15.8) compared to 13 months (95% CI 7.7-14.2) for those with metachronous SM (p = 0.74).

CONCLUSIONS

Our findings suggest that the timing of SM diagnosis (synchronous versus metachronous) does not significantly affect survival outcomes following neurosurgical treatment for SM. These results support the consideration of neurosurgical procedures regardless of the temporal pattern of SM manifestation.

The Impact of the COVID-19 Pandemic on the Presentation of Patients With Spinal Metastases

STUDY DESIGN

Retrospective review.

OBJECTIVE

The aim was to determine if preoperative spinal instability neoplastic scores (SINSs) and Tokuhashi prognostication scores differed in patients receiving surgical care before and during the coronavirus disease-2019 (COVID-19) pandemic.

SUMMARY OF BACKGROUND DATA

The COVID-19 pandemic has caused delays in scheduling nonemergent surgeries. Delay in presentation and/or surgical treatment for oncology patients with metastatic spinal disease could result in progression of the disease, which can complicate surgical care and worsen patient outcomes.

MATERIALS AND METHODS

Retrospective review of electronic medical records between March 1, 2019 and March 1, 2021 at a tertiary medical center was performed to identify patients who underwent surgery for metastatic spine disease. Primary spinal tumors were excluded. Patients were separated into two groups base on their surgery date: before the COVID-19 pandemic (March 1, 2019-February 29, 2020) and during the COVID-19 pandemic (March 1, 2020-March 1, 2021). Primary outcomes included SINS and Tokuhashi scores. A variety of statistical tests were performed to compare the groups.

RESULTS

Fifty-two patients who underwent surgery before the COVID-19 pandemic were compared to 41 patients who underwent surgery during the COVID-19 pandemic. There was a significant difference between the before and during groups with respect to SINS (9.31±2.39 vs . 11.00±2.74, P =0.002) and Tokuhashi scores (9.27±2.35 vs . 7.88±2.85, P =0.012). Linear regression demonstrated time of surgery (before or during COVID-19 restrictions) was a significant predictor of SINS (β=1.55, 95% CI: 0.42-2.62, P =0.005) and Tokuhashi scores (β=-1.41, 95% CI: -2.49 to -0.34, P =0.010).

CONCLUSIONS

Patients with metastatic spinal disease who underwent surgery during the COVID-19 pandemic had higher SINS, lower Tokuhashi scores and similar Skeletal Oncology Research Group scores compared to patients who underwent surgery before the pandemic. This suggests the pandemic has impacted the instability of disease at presentation in patients with spinal metastases, but has not impacted surgical prognosis, as there were no differences in Skeletal Oncology Research Group scores and the difference in Tokuhashi scores is most likely not clinically significant.

A Comparison of Prognostic Models to Facilitate Surgical Decision-Making for Patients With Spinal Metastatic Disease

STUDY DESIGN

Retrospective cohort.

OBJECTIVE

Compare the performance of and provide cutoff values for commonly used prognostic models for spinal metastases, including Revised Tokuhashi, Tomita, Modified Bauer, New England Spinal Metastases Score (NESMS), and Skeletal Oncology Research Group model, at three- and six-month postoperative time points.

SUMMARY OF BACKGROUND DATA

Surgery may be recommended for patients with spinal metastases causing fracture, instability, pain, and/or neurological compromise. However, patients with less than three to six months of projected survival are less likely to benefit from surgery. Prognostic models have been developed to help determine prognosis and surgical candidacy. Yet, there is a lack of data directly comparing the performance of these models at clinically relevant time points or providing clinically applicable cutoff values for the models.

MATERIALS AND METHODS

Sixty-four patients undergoing surgery from 2015 to 2022 for spinal metastatic disease were identified. Revised Tokuhashi, Tomita, Modified Bauer, NESMS, and Skeletal Oncology Research Group were calculated for each patient. Model calibration and discrimination for predicting survival at three months, six months, and final follow-up were evaluated using the Brier score and Uno's C, respectively. Hazard ratios for survival were calculated for the models. The Contral and O'Quigley method was utilized to identify cutoff values for the models discriminating between survival and nonsurvival at three months, six months, and final follow-up.

RESULTS

Each of the models demonstrated similar performance in predicting survival at three months, six months, and final follow-up. Cutoff scores that best differentiated patients likely to survive beyond three months included the Revised Tokuhashi score=10, Tomita score=four, Modified Bauer score=three, and NESMS=one.

CONCLUSION

We found comparable efficacy among the models in predicting survival at clinically relevant time points. Cutoff values provided herein may assist surgeons and patients when deciding whether to pursue surgery for spinal metastatic disease.

LEVEL OF EVIDENCE

4.

Cross-link augmentation enhances CFR-PEEK short fixation in lumbar metastasis stabilization

Introduction: Spinal stability plays a crucial role in the success of the surgical treatment of lumbar vertebral metastasis and, in current practice, less invasive approaches such as short constructs have been considered. Concurrently, carbon fiber-reinforced (CFR) poly-ether-ether-ketone (PEEK) fixation devices are expanding in oncologic spinal surgery thanks to their radiotransparency and valid mechanical properties. This study attempts to provide an exhaustive biomechanical comparison of different CFR-PEEK surgical stabilizations through a highly reproducible experimental setup. Methods: A Sawbones biomimetic phantom (T12-S1) was tested in flexion, extension, lateral bending, and axial rotation. An hemisome lesion on L3 vertebral body was mimicked and different pedicle screw posterior fixations were realized with implants from CarboFix Orthopedics Ltd: a long construct involving two spinal levels above and below the lesion, and a short construct involving only the levels adjacent to L3, with and without the addition of a transverse rod-rod cross-link; to provide additional insights on its long-term applicability, the event of a pedicle screw loosening was also accounted. Results: Short construct reduced the overloading onset caused by long stabilization. Particularly, the segmental motion contribution less deviated from the physiologic pattern and also the long-chain stiffness was reduced with respect to the prevalent long construct. The use of the cross-link enhanced the short stabilization by making it significantly stiffer in lateral bending and axial rotation, and by limiting mobiliza-tion in case of pedicle screw loosening. Discussion: The present study proved in vitro the biomechanical benefits of cross-link augmentation in short CFR-PEEK fixation, demonstrating it to be a potential alternative to standard long fixation in the surgical management of lumbar metastasis.

Postoperative prolonged mechanical ventilation correlates to poor survival in patients with surgically treated spinal metastasis

Objective

Patients with spinal metastasis (SM) are at advanced stages of systemic cancer disease. Surgical therapy for SM is a common treatment modality enabling histopathological diagnosis and the prevention of severe neurological deficits. However, surgery for SM in this vulnerable patient cohort may require prolonged postoperative intensive care treatment, which could adversely affect the anticipated benefit of the surgery. We therefore assessed postoperative prolonged mechanical ventilation (PMV) as an indicator for intensive care treatment with regard to potential correlations with early postoperative mortality and overall survival (OS).

Methods

Between 2015 and 2019, 198 patients were surgically treated for SM at the author´s neurosurgical department. PMV was defined as postoperative mechanical ventilation of more than 24 hours. A multivariate analysis was performed to identify pre- and perioperative collectable predictors for 30 days mortality.

Results

Twenty out of 198 patients (10%) with SM suffered from postoperative PMV. Patients with PMV exhibited a median OS rate of 1 month compared to 12 months for patients without PMV (p < 0.0001). The 30 days mortality was 70% and after one year 100%. The multivariate analysis identified “PMV > 24 hrs” (p < 0.001, OR 0.3, 95% CI 0.02-0.4) as the only significant and independent predictor for 30 days mortality (Nagelkerke’s R2 0.38).

Conclusions

Our data indicate postoperative PMV to significantly correlate to high early postoperative mortality rates as well as to poor OS in patients with surgically treated SM. These findings might encourage the initiation of further multicenter studies to comprehensively investigate PMV as a so far underestimated negative prognostic factor in the course of surgical treatment for SM.

Follicular carcinoma of the thyroid with a single metastatic lesion in the lumbar spine: A case report

BACKGROUND

The bone is the second most common site of thyroid cancer metastasis, after the lung. Treatment options for bone metastasis of thyroid cancer include surgery, radioiodine therapy (RAIT), external radiation therapy, thyroid-stimulating hormone (TSH) inhibition, bisphosphonates, and small-molecule targeted therapies. In most cases, thyroid carcinoma is found in the thyroid tissue; reports of follicular thyroid carcinoma with a single metastasis to the lumbar spine are rare.

CASE SUMMARY

We report a case of bone metastasis as the only clinical manifestation of thyroid cancer. The patient was a 67-year-old woman with lumbar pain for 7 years and aggravation with intermittent claudication who had previously undergone partial thyroidectomy of a benign thyroid lesion. No abnormal nodules were found in the bilateral thyroid glands. However, imaging studies were consistent with a spinal tumor, and the lesion was diagnosed as a metastatic follicular carcinoma of thyroid origin. We adopted a multidisciplinary collaboration and comprehensive treatment approach. The patient underwent lumbar spine surgery, total resection of the thyroid, postoperative TSH suppression therapy, and RAIT. There were no complications associated with the operation, and the patient had good postoperative recovery. She has experienced no recurrence.

CONCLUSION

Follicular thyroid carcinoma is associated with early hematogenous metastasis, and the bone is a typical site of metastasis. Single bone metastasis is not a contraindication to medical procedures, and providing the appropriate therapy can result in better outcomes and quality of life for these patients.

Toward an artificial intelligence-assisted framework for reconstructing the digital twin of vertebra and predicting its fracture response

This article presents an effort toward building an artificial intelligence (AI) assisted framework, coined ReconGAN, for creating a realistic digital twin of the human vertebra and predicting the risk of vertebral fracture (VF). ReconGAN consists of a deep convolutional generative adversarial network (DCGAN), image-processing steps, and finite element (FE) based shape optimization to reconstruct the vertebra model. This DCGAN model is trained using a set of quantitative micro-computed tomography (micro-QCT) images of the trabecular bone obtained from cadaveric samples. The quality of synthetic trabecular models generated using DCGAN are verified by comparing a set of its statistical microstructural descriptors with those of the imaging data. The synthesized trabecular microstructure is then infused into the vertebra cortical shell extracted from the patient's diagnostic CT scans using an FE-based shape optimization approach to achieve a smooth transition between trabecular to cortical regions. The final geometrical model of the vertebra is converted into a high-fidelity FE model to simulate the VF response using a continuum damage model under compression and flexion loading conditions. A feasibility study is presented to demonstrate the applicability of digital twins generated using this AI-assisted framework to predict the risk of VF in a cancer patient with spinal metastasis.

Minimally invasive separation surgery for the treatment of spinal metastases with small incision and freehand pedicle screw fixation: the surgical learning curve

BACKGROUND

Minimally invasive separation surgery (MISS) is a safe and effective surgical technique, the current optimal treatment for spinal metastases. However, the learning curve for this technique has not been analyzed. This study aimed to define and analyze the surgical learning curve of MISS for the treatment of spinal metastases with small incision and freehand pedicle screw fixation.

METHODS

A continuous series of 62 patients with spinal metastases who underwent MISS were included. Each patient's operative data were accurately counted. The improvement of the patients' neurological function was followed up after surgery to evaluate the surgical treatment effect. Logarithmic curve-fit regression was used to analyze the surgical learning curve of MISS. The number of cases needed to achieve proficiency was analyzed. Based on this cut-off point, this series of cases was divided into the early phase and later phase groups. The influence of the time sequence of MISS on surgical data and surgical efficacy was analyzed.

RESULTS

The operative time decreased gradually with the number of surgical cases increasing and stabilized after the 20th patient. There was no statistical difference in demographic characteristics and preoperative characteristics between the two groups. The mean operative time in the later phase group was about 39 min shorter than that in the early phase group (mean 227.95 vs. 189.02 min, P = 0.027). However, it did not affect other operative data or the surgical treatment effect.

CONCLUSION

The learning curve of MISS for spinal metastases is not steep. With the increase of surgeons' experience, the operative time drops rapidly and stabilizes within a certain range. MISS can be safely and effectively performed at the beginning of a surgeon's caree.

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.

Estimating survival and choosing treatment for spinal metastases: Do spine surgeons agree with each other?

Purpose

This study aimed to investigate spine surgeons’ ability to estimate survival in patients with spinal metastases and whether survival estimates influence treatment recommendations.

Methods

60 Spine surgeons were asked a survival estimate and treatment recommendation in 12 cases. Intraclass correlation coefficients and descriptive statistics were used to evaluate variability, accuracy and association of survival estimates with treatment recommendation.

Results

There was substantial variability in survival estimates amongst the spine surgeons. Survival was generally overestimated, and longer estimated survival seemed to lead to more invasive procedures.

Conclusions

Prognostic models to estimate survival may aid surgeons treating patients with spinal metastases.

Sternotomy Approach to the Anterior Cervicothoracic Spine

The anterior cervicothoracic spine is a challenging region to approach given the various vascular, osseous, nervous, and articular structures, which prevent adequate exposure. This region is susceptible to lesions ranging from tumors, degenerative disease, infectious processes, and traumatic fractures. Our objective was to critically evaluate the sternotomy approach in spine surgery to give the technical implications of its usage. The safety and efficacy of the transsternal approach are discussed as well as the advantages, disadvantages, indications, and contraindications. The transsternal approach is the most direct access to pathologies in the upper anterior cervicothoracic spine and enables the spine surgeon to gain direct exposure to the cervicothoracic junction for ideal visualization. Anatomical considerations must be kept in mind while performing a sternotomy to prevent complications such as denervation or bleeding. This technique is useful for the armamentarium of spinal surgeons.

Temperature Monitoring in Hyperthermia Treatments of Bone Tumors: State-of-the-Art and Future Challenges

Bone metastases and osteoid osteoma (OO) have a high incidence in patients facing primary lesions in many organs. Radiotherapy has long been the standard choice for these patients, performed as stand-alone or in conjunction with surgery. However, the needs of these patients have never been fully met, especially in the ones with low life expectancy, where treatments devoted to pain reduction are pivotal. New techniques as hyperthermia treatments (HTs) are emerging to reduce the associated pain of bone metastases and OO. Temperature monitoring during HTs may significantly improve the clinical outcomes since the amount of thermal injury depends on the tissue temperature and the exposure time. This is particularly relevant in bone tumors due to the adjacent vulnerable structures (e.g., spinal cord and nerve roots). In this Review, we focus on the potential of temperature monitoring on HT of bone cancer. Preclinical and clinical studies have been proposed and are underway to investigate the use of different thermometric techniques in this scenario. We review these studies, the principle of work of the thermometric techniques used in HTs, their strengths, weaknesses, and pitfalls, as well as the strategies and the potential of improving the HTs outcomes.

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.

Minimally invasive surgery for spinal fractures due to multiple myeloma

Background:

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

Objective:

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

Methods:

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

Results:

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

Conclusions:

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

A Comparative Study Between Minimally Invasive Spine Surgery and Traditional Open Surgery for Patients With Spinal Metastasis

STUDY DESIGN

A retrospective study was conducted.

OBJECTIVE

This study aims to compare the perioperative outcomes of minimal invasive spine surgery (MISS) and traditional open surgery (TOS) for thoracolumbar spine metastasis.

SUMMARY OF BACKGROUND DATA

TOS for metastatic spinal tumors has many disadvantages, such as significant blood loss and high complication rate. MISS may change the treatment modality, but its safety and efficacy for spinal metastasis are lacking.

METHODS

We retrospectively reviewed clinical data from 154 consecutive patients registered in our institute who underwent separation surgery for spinal metastases from January 2017 to December 2019. Forty-nine patients received MISS and 105 patients had TOS. The demographic and perioperative data were collected and compared between two approaches.

RESULTS

There were no significant differences in baseline characteristics between the MISS and TOS group, except the sex (P = 0.04). The mean intraoperative blood loss in MISS group was lower than that in TOS group (748.57 vs. 950.48 mL, P = 0.039). The operative time was comparable between both groups (mean 213.45 vs. 221.03 minutes, P = 0.78). The postoperative drainage before discharge in MISS group was remarkably less than that in TOS group (mean 494.02 vs. 1099.10 mL, P = 0.0004). As compared to TOS group, patients in MISS group had lower complication rate, although the difference is not significant (9.52% vs. 6.12%, P = 0.55). The infection rate of MISS group was two-fold lower than that in the TOS group, although the difference is not significant (P = 0.43). The mean hospital stay of MISS group is 7.35 days, which is significantly shorter than TOS group (9.94 days, P = 0.0007). Patients in both groups exhibited similar postoperative neurological outcomes.

CONCLUSION

MISS is a safe and effective technique that could be considered the optimal treatment for patients with spinal metastasis and myelopathy and thus is an excellent alternative in managing thoracolumbar spine metastasis.

LEVEL OF EVIDENCE

3.

Metastasectomy and Targeted Therapy for Patients With Spinal Metastases of Renal Cell Carcinoma

BACKGROUND

Renal cell carcinoma (RCC) is an aggressive malignant disease that frequently metastasizes to the spine. The main purpose of our study is to evaluate the influence of surgery as well as targeted therapy on the survival of patients with RCC metastases of the spine.

METHODS

Retrospective cohort study. We identified 100 patients with spinal RCC metastases who were retrospectively reviewed for preoperative conditions, treatment, and survival. Metastasectomy was performed in 39 cases, and 61 patients underwent decompression procedures with stabilization. Only 26 patients had adjuvant targeted therapy (7 with metastasectomy, 19 with palliative decompression). Pain, neurological status, survival time (from operation to death or last follow up), and local progression-free survival were evaluated.

RESULTS

Neurological function recovery and reported significant pain relief were observed. There was no significant difference in overall survival for the patients with metastasectomy and palliative decompression (P = .750). Metastasectomy provided better local control of disease compared with decompression (P = .043). There was a statistically significant difference in overall survival for the patients who received targeted therapy (P = .012).

CONCLUSIONS

Metastasectomy is effective for local control of tumors. Targeted therapy can potentially prolong overall survival for patients with spinal RCC metastases.

LEVEL OF EVIDENCE

3.

CLINICAL RELEVANCE

Our findings suggest that spinal metastasectomy is useful for local control of tumor growth but not for live expectancy. Effective systemic therapy is key role in stopping of disease progression.

Incidence and Risk Factors for Implant Failure in Spinal Metastasis Surgery

STUDY DESIGN

Retrospective study.

PURPOSE

To investigate the incidence of symptomatic and asymptomatic implant failure in spinal metastasis surgery and identify potential risk factors.

OVERVIEW OF LITERATURE

Surgical stabilization with instrumentation is an established method for the treatment of spinal metastasis. However, very few studies have investigated the incidence and risk factors for implant failure after spinal instrumentation surgery for the treatment of spinal metastasis.

METHODS

This study recruited 88 patients who received surgical stabilization with instrumentation for the treatment of spinal metastasis. Their medical records and postoperative X-rays were reviewed for evidence of implant failure. Statistical analysis with logistic regression was performed to assess nine potential risk factors for the development of implant failure, including patient's age at operation, gender, survival, primary tumor, spinal level involved, construct length, decompression levels, fusion material utilization, and radiotherapy application either before or after surgery, to identify potential contributing risk factors.

RESULTS

Implant failure was identified in nine out of 88 cases (10.2%) with two cases requiring implant removal: one case included a progressive kyphosis that resulted in nonhealing sore and the other involved a deep-seated wound infection that spread to the implants. Another case required wound debridement due to superficial wound infection. The remaining six cases were asymptomatic, despite postoperative X-rays demonstrating evidence of implant failure. No patient required implant revision. Logistic regression analysis demonstrated that patients who received radiotherapy either before or after surgery were less likely to develop implant failure.

CONCLUSIONS

The development of radiological implant failure following surgical treatment of spinal metastasis is common. However, symptomatic implant failure leading to revision surgery is uncommon. Our findings suggest that radiotherapy, either before or after spinal surgery, is not associated with the development of implant failure.

Kyphoplasty in the treatment of occult and non-occult metastatic vertebral tumors

To compare the efficacy and safety of kyphoplasty (KP) in the treatment of occult metastatic vertebral tumors (OMVT) and non-occult metastatic vertebral tumors (MVT).From January 2013 to December 2017, 65 cases of occult metastatic vertebral tumors and 82 cases of metastatic vertebral tumors were selected and divided into 2 groups. After KP, they were followed up by a year of outpatient visits and telephone calls. The visual analogue scale (VAS) and Oswestry disability index (ODI) scores, the amount of bone cement injected, the change of vertebral height and the incidence of complications were recorded, compared and analyzed by SPSS software. t test was used to compare the differences between the same group of patients at different times and between the 2 groups of patients.In the OMVT group, the operation time was 24.52 ± 4.24 minutes, the fluoroscopy time was 10.18 ± 1.53 minutes and the volume of bone cement was 3.62 ± 0.93 ml. The VAS score decreased from 7.26 ± 01.08 preoperatively to 2.77 ± 0.93 postoperatively (P < .01). The ODI score decreased from 64.89 ± 9.05 preoperatively to 25.82 ± 4.63 postoperatively (P < .01). In the MVT group, the operation time was 26.63 ± 4.61 minutes, the fluoroscopy time was 11.04 ± 2.15 minutes and the volume of bone cement was 4.09 ± 1.10 ml. The VAS score decreased from 7.73 ± 0.94 preoperatively to 3.22 ± 0.80 postoperatively (P < .01). The ODI score decreased from 69.20 ± 7.14 preoperatively to 28.02 ± 4.40 postoperatively (P < .01). The vertebral height of MVT patients was significantly improved after operation (P < .01), but there was no difference in OMVT patients (P > .05).Occult metastatic vertebral tumors can be detected by Magnetic Resonance Imaging (MRI), and KP may be more effective and safer in the treatment of OMVT.

Risk Factors for Wound-Related Complications After Surgery for Primary and Metastatic Spine Tumors: A Systematic Review and Meta-Analysis

OBJECTIVE

We systematically reviewed the literature to compare risk factors for postoperative complications at the surgical wound site in primary and metastatic tumor operations.

METHODS

We screened English-language publications on the outcomes of primary and metastatic spinal tumor operations. Pooled analyses and meta-analyses with random-effects modeling were performed comparing patients with and without wound complications, which were defined as surgical site infection or sterile wound dehiscence.

RESULTS

Our search identified 5471 unique citations, from which we included 23 studies describing 5104 patients. A total of 1936 patients underwent surgery for primary tumors, with a wound complication rate of 8.1%. Subgroup analysis of benign and malignant primary tumors yielded significantly different wound complication rates of 7.8% and 26.9%, respectively. The metastatic tumor cohort included 168 patients and a complication rate of 6.6%. In a pooled analysis of primary tumors, higher wound complication rates were associated with sacral operations and the use of instrumentation. In the metastatic tumor cohort, higher complication rates were associated with female sex, smoking history, preoperative chemotherapy, preoperative radiotherapy, corticosteroid use, and previous spine surgery. Instrumentation remained a statistically significant risk factor for primary tumors with the addition of random-effects meta-analysis.

CONCLUSIONS

Risk factors for wound complications after primary tumor operations were related to tumor histology and the spinal location of the operation. Risk factors for metastatic tumors may be related to several systemic preoperative treatments and baseline comorbidities. Random-effects meta-analysis showed the limited generalizability of these findings because of the small heterogenous primary literature.

Clinical prevalence and population incidence of serious pathologies among patients undergoing magnetic resonance imaging for low back pain

BACKGROUND

In rare cases low back pain may be caused by underlying serious pathology such as fracture, malignancy, cauda equina syndrome, or spinal infection. The lack of evidence regarding either the clinical prevalence or population incidence of serious pathologies in the lumbar spine makes it difficult for clinicians to adequately assess a patient's risk of serious pathology.

PURPOSE

To determine the prevalence of serious pathologies in patients with low back pain who have been referred for a lumbar magnetic resonance imaging (MRI) by a specialist in a private secondary care or public tertiary care setting. The incidence of these serious pathologies in the geographic region of South Auckland, New Zealand was also investigated.

STUDY DESIGN

Retrospective, observational cohort study.

PATIENT SAMPLE

Consecutive patients referred for lumbar MRI over a 10-month period (1st of October 2013-31st of July 2014).

METHOD

Data from all eligible MRI reports was analyzed and any serious pathologies were identified and recorded. Prevalence (along with 95% confidence intervals) was calculated as a percentage of the study population. Prevalence specific to private secondary care and public tertiary care settings was also calculated and prevalence rate ratios were determined to allow comparison between settings. Incidence in the geographic region of South Auckland, New Zealand, was determined using data collected from participants recruited from the regional public hospital. Population incidence with respect to age, gender, and ethnicity for each target condition was calculated and incidence rate ratios were computed to compare groups.

RESULTS

A total of 2,383 participants referred for lumbar MRI scans were included in this study. Prevalence was significantly higher in the public tertiary care setting than in the private secondary care setting for all pathologies investigated in this study. Pathology specific prevalence in secondary care vs tertiary care settings was: malignancy, 0.3%, 4.4% (p<.001); fracture 2.2%, 6.7% (p<.001); cauda equina compression 0.6%, 2.3% (p=.001); infection 0.1%, 3.4% (p<.001). The combined prevalence in secondary care was 3.2% and in tertiary care 14.8% (p<.001). Pathology specific total incidence was: fracture, 13 per 100,000 person-years (p-y); malignancy 8.5 per 100,000 p-y; cauda equina compression 4.4 per 100,000 p-y; spinal infection 6.6 per 100,000 p-y.

CONCLUSIONS

The prevalence of serious pathologies was significantly higher in tertiary care (public health) than in private secondary care settings. One in every 6.5 patients referred for MRI in tertiary care demonstrated structural abnormalities associated with serious pathology, which raises the question of whether access to MRI should be re-evaluated.

Epidemiological Characteristics of 1196 Patients with Spinal Metastases: A Retrospective Study

OBJECTIVES

To describe the epidemiological characteristics of patients with spinal metastases between 2007 and 2019.

METHODS

Patients with spinal metastases were identified from several clinical centers in China between January 2007 and July 2019. Demographics, primary tumor types, spinal involvement, and Clinical indicators of each patient were reviewed.

RESULTS

A total of 1196 patients were included in this study, 717 males (59.95%) and 479 females (40.05%), with a male to female ratio of 1.50:1. Most patients (63.71%) were in the ages range of 50 to 69 years. The mean age was 58.6 ± 11.6 (range 13-89) years and the median age was 59.0 years. The average age of females was younger than that of males, and the difference was statistically significant. The proportion of male patients over 60 years old was higher than that of females, and the difference was statistically significant. The most common primary tumor was lung cancer (n = 437, 36.54%), followed by unknown origin (n = 194, 16.22%), kidney cancer (n = 78, 6.52%), breast cancer (n = 76, 6.35%), and liver/biliary cancer (n = 75, 6.27%). The most common primary tumor was lung cancer in both males and females, followed by unknown origin in males and breast cancer in females. There were 730 patients (61.04%) in the subgroup of the number<3; the highest level was lumbar vertebrae, with 250 patients (34.25%). The remaining 466 patients (38.96%) were included in the subgroup of the number ≥ 3; the highest level was tumor metastasis of multiple-level of spine, with 334 patients (71.67%). Among the 1196 patients, spinal cord injury occurred in 54.01% of patients, 76.34% of patients developed moderate and above pain, 55.69% of patients had metastatic spinal cord compression, and only 26.67% of patients had a clear history of primary tumors.

CONCLUSION

This study provided a relatively detailed description of epidemiological characteristics in spinal metastases in China, which could assist orthopaedic surgeons to understand the clinical characteristics of spinal metastases, and is of great significance in guiding clinical diagnoses and scientific research.

The Role of Stabilization-Free Microsurgical Decompression in the Surgical Treatment of Spinal Metastases

OBJECTIVE

Symptomatic spine metastases are found in about 10% of patients with cancer. As the long-term survival of patients with carcinoma rises, the number of patients with symptomatic spine metastases is also increasing. In our tertiary referral center, patients usually present rapidly progressive neurologic disorders, which require an urgent treatment decision. Treatment options include extensive 360° stabilizations. These complex interventions are not always readily available. We examined the extent to which the patient population benefited from decompressive surgery without stabilization. We hypothesize that patients benefit from merely dorsal decompression, which preserves stability when they experience symptomatic spine metastases.

METHODS

We performed a retrospective analysis of electronic patient data from 19 patients, who were treated for symptomatic spine metastases by hemilaminectomy between 2009 and 2017. We evaluated the preoperative and postoperative neurologic functions using the American Spinal Injury Association (ASIA) Impairment Scale. A comparative literature analysis was carried out to assess the Spinal Neoplastic Instability Score, Tokuhashi score, and Tomita score.

RESULTS

Nine participants had prostate cancer, 4 had mammary carcinoma, 3 had bronchial carcinoma, and 3 had other cancers. The median preoperative ASIA score was C, postoperatively, the score significantly improved to D (sign test P = 0.002). None of the patients needed stabilization within the follow-up period of up to 56 months.

CONCLUSIONS

In our patient population, minimal intervention could significantly improve neurologic disorders. This outcome was seen over the whole study period. Even though different scoring systems suggest stabilization, our results show that spinal decompression alone might be indicated as well.

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.

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.

Minimally Invasive Surgery without Decompression for Hepatocellular Carcinoma Spinal Metastasis with Epidural Spinal Cord Compression Grade 2

Objective

There is a lack of knowledge regarding whether decompression is necessary in treating patients with epidural spinal cord compression (ESCC) grade 2. The purpose of this study was to compare the outcomes of minimally invasive surgery (MIS) without decompression and conventional open surgery (palliative laminectomy) for patients with hepatocellular carcinoma (HCC) spinal metastasis of ESCC grade 2.

Methods

Patients with HCC spinal metastasis requiring surgery were retrospectively reviewed. Patients with ESCC grade 2, medically intractable mechanical back pain, a Nurick grade better than 3, 3–6 months of life expectancy, Tomita score ≥5, and Spinal Instability Neoplastic Score ≥7 were included. Patients with neurological deficits, other systemic illnesses and less than 1 month of life expectancy were excluded. Thirty patients were included in the study, including 17 in the open surgery group (until 2008) and 13 in the MIS group (since 2009).

Results

The MIS group had a significantly shorter operative time (94.2±48.2 minutes vs. 162.9±52.3 minutes, p=0.001), less blood loss (140.0±182.9 mL vs. 1534.4±1484.2 mL, p=0.002), and less post-operative intensive care unit transfer (one patient vs. eight patients, p=0.042) than the open surgery group. The visual analogue scale for back pain at 3 months post-operation was significantly improved in the MIS group than in the open surgery group (3.0±1.2 vs. 4.3±1.2, p=0.042). The MIS group had longer ambulation time (183±33 days vs. 166±36 days) and survival time (216±38 days vs. 204±43 days) than the open surgery group without significant difference (p=0.814 and 0.959, respectively).

Conclusion

MIS without decompression would be a good choice for patients with HCC spinal metastasis of ESCC grade 2, especially those with limited prognosis, mechanical instability and no neurologic deficit.

Malignant Spinal Cord Compression: Adapting Conventional Rehabilitation Approaches

Spinal tumors are classically grouped into 3 categories: extradural, intradural extramedullary, and intradural intramedullary. Spinal tumors may cause spinal cord compression and vascular compromise resulting in pain or neurologic compromise. They may also alter the architecture of the spinal column, resulting in spinal instability. Oncologic management of spinal tumors varies according to the stability of the spine, neurologic status, and presence of pain. Treatment options include surgical intervention, radiation therapy, chemotherapy, and hormonal manipulation. When combined with this management, rehabilitation can serve to relieve symptoms, improve quality of life, enhance functional independence, and prevent further complications in patients.

Outcomes and prognostic factors for surgically treated patients with breast cancer spine metastases

Purpose

The aim of this study is to provide some useful insights into the treatments, outcomes, and prognostic factors of patients with breast cancer spine metastases (BCSM).

Methods

We report a retrospective case series analyzing 87 patients with BCSM who underwent surgical interventions. Independent prognostic factors for SMFS and OS were extracted using univariate and multivariate analyses, the Kaplan-Meier method and the Cox proportional hazards model.

Results

The mean time between primary diagnoses and spinal metastases was 46.8 (median 41, range 0-147 months) months. The analysis showed that lymph node metastasis (p = 0.043, HR 10.498, 95%CI 1.074-102.588) and estrogen receptor (ER) status (p = 0.004, HR 0.368, 95%CI 0.189-0.721) can significantly affect SMFS. Furthermore, visceral metastasis (p = 0.042, HR 2.383, 95%CI 1.032-5.501), multiple metastases (p = 0.035, HR 2.538, 95%CI 1.066-6.048) and post-op chemotherapy (p = 0.003, HR 0.312, 95%CI 0.144-0.675) have significant effects on OS. Lastly, patients identified as Luminal A subtype have longer OS.

Conclusions

Lymph node metastases and ER status are independent risk factors in predicting BCSM. Moreover, visceral metastasis, multiple metastases of the spine and post-op chemotherapy are independent prognostic factors. Luminal subtypes have higher rate, but late onset of spine metastases and prolonged survival.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Acute Lumbar Back Pain

BACKGROUND

Back pain has many causes. In Germany, about 70% of adults have at least one episode of back pain per year.

METHODS

This review is based on a selective literature search and on the German National Disease Management Guideline for Low Back Pain.

RESULTS

The physician taking the history from a patient with back pain should ask about the nature, onset, course, localization, and radiation of the pain and its dependence on physical activity and/or emotional stress. In the differential diagnosis, neurologic deficits and any "red flags" suggesting dangerous conditions such as spinal fracture, bacterial infection, and tumors must be ruled out. If no specific cause of the pain can be identified, no imaging studies are indicated on initial presentation. The treatment of acute, nonspecific low back pain focuses on pain relief and functional improvement. Adequate patient education and counseling are essential. Exercise therapy is no more effective than the continuation of normal daily activities. Restriction of activity, including bed rest, is of no benefit and merely prolongs recovery and the resumption of normal activity. Further diagnostic testing is indicated if there is any suspicion of a fracture, infection, or tumor.

CONCLUSION

After dangerous conditions have been ruled out, low back pain can be pragmatically classified as either nonspecific or specific. More research is needed so that the diagnostic assessment and individualized treatment of acute lower back pain can be further refined.

Metastatic human breast cancer to the spine produces mechanical hyperalgesia and gait deficits in rodents

BACKGROUND CONTEXT

Metastases to the spine are a common source of severe pain in cancer patients. The secondary effects of spinal metastases include pain, bone fractures, hypercalcemia, and neurological deficits. As the disease progresses, pain severity can increase until it becomes refractory to medical treatments and leads to a decreased quality of life for patients. A key obstacle in the study of pain-induced spinal cancer is the lack of reliable and reproducible spine cancer animal models. In the present study, we developed a reproducible and reliable rat model of spinal cancer using human-derived tumor tissue to evaluate neurological decline using imaging and behavioral techniques.

PURPOSE

The present study outlines the development and characterization of an orthotopic model of human breast cancer to the spine in immunocompromised rats.

STUDY DESIGN/SETTING

This is a basic science study.

METHODS

Female immunocompromised rats were randomized into three groups: tumor (n=8), RBC3 mammary adenocarcinoma tissue engrafted in the L5 vertebra body; sham (n=6), surgery performed but not tumor engrafted; and control (n=6), naive rats, no surgery performed. To evaluate the neurological impairment due to tumor invasion, functional assessment was done in all rodents at day 40 after tumor engraftment using locomotion gait analysis and pain response to a mechanical stimulus (Randall-Selitto test). Bioluminescence (BLI) was used to evaluate tumor growth in vivo and cone beam computed tomography (CBCT) was performed to evaluate bone changes due to tumor invasion. The animals were euthanized at day 45 and their spines were harvested and processed for hematoxylin and eosin (H&E) staining.

RESULTS

Tumor growth in the spine was confirmed by BLI imaging and corroborated by histological analysis. Cone beam computed tomography images were characterized by a decrease in the bone intensity in the lumbar spine consistent with tumor location on BLI. On H&E staining of tumor-engrafted animals, there was a near-complete ablation of the ventral and posterior elements of the L5 vertebra with severe tumor invasion in the bony components displacing the spinal cord. Locomotion gait analysis of tumor-engrafted rats showed a disruption in the normal gait pattern with asignificant reduction in length (p=.02), duration (p=.002), and velocity (p=.002) of right leg strides and only in duration (p=.0006) and velocity (p=.001) of left leg strides, as compared with control and sham rats. Tumor-engrafted animals were hypersensitive to pain stimulus shown as a significantly reduced response in time (p=.02) and pressure (p=.01) applied when compared with control groups.

CONCLUSIONS

We developed a system for the quantitative analysis of pain and locomotion in an animal model of metastatic human breast cancer of the spine. Tumor-engrafted animals showed locomotor and sensory deficits that are in accordance with clinical manifestation in patients with spine metastasis. Pain response and locomotion gait analysis were performed during follow-up. The Randall-Selitto test was a sensitive method to evaluate pain in the rat's spine. We present a model for the study of bone-associated cancer pain secondary to cancer metastasis to the spine, as well as for the study of new therapies and treatments to lessen pain from metastatic cancer to the neuroaxis.

Hardware failure in patients with metastatic cancer to the spine

BACKGROUND

The spine is the most common site of skeletal metastases, affecting approximately 30% of individuals with cancer. The aim of surgical treatment for metastatic spine disease is generally palliative to address pain and/or neurologic compromise, significantly improving patients' quality of life. Patients with metastatic spine disease, however, represent a vulnerable cohort and may have comorbidities or previous treatments that impair the structural integrity of spinal hardware. As such, identifying factors that may contribute to hardware failure is an essential component in treating individuals with metastatic spine disease.

OBJECTIVE

The aim of this study was to identify pre-operative risk factors associated with hardware failure in patients undergoing surgical treatment for metastatic spine disease.

METHODS

A retrospective cohort study was conducted to include patients surgically treated for metastatic spine tumors between 2003 and 2013, at a single institution. A univariate analysis was initially performed to identify associated factors. Any associated factor with a p-value <0.20 was included in the multivariate analysis.

RESULTS

3 patients (1.9%), of the 159 patients included in the study, had failure of the spine instrumentation. 1 patient had metastatic prostate cancer, and 2 had metastatic breast cancer. Patient demographics, co-morbidities, tumor location, and primary tumor etiology were not found to be statistically significant, with respect to hardware failure. Predictive factors included in the multivariate model were other bone metastasis, visceral metastasis, brain metastasis, Modified Rankin scale, previous systemic chemotherapy, previous radiation to the spine, and mean survival. Previous radiation to the spine was the only factor to be significantly associated (p=0.029), present in all three patients with hardware failure. Of note, there was a trend indicating that patients with longer life expectancies were more likely to experience hardware failure (mean survival of 16.7months in non-failure cohort vs. 33months in failure cohort), though this did not achieve statistical significance due to the limited sample size of patients with hardware failure.

CONCLUSION

Hardware failure is a risk for all patients who undergo instrumentation following resection for metastatic spine tumors. This study identified that pre-operative radiation may increase the risk for hardware failure in this population.

Incidence and risk factors for preoperative deep venous thrombosis in 314 consecutive patients undergoing surgery for spinal metastasis

OBJECTIVE The authors of this study aimed to identify the incidence of and risk factors for preoperative deep venous thrombosis (DVT) in patients undergoing surgical treatment for spinal metastases. METHODS Univariate analysis of patient age, sex, ethnicity, laboratory values, comorbidities, preoperative ambulatory status, histopathological classification, spinal level, and surgical details was performed. Factors significantly associated with DVT univariately were entered into a multivariate logistic regression model. RESULTS The authors identified 314 patients, of whom 232 (73.9%) were screened preoperatively for a DVT. Of those screened, 22 (9.48%) were diagnosed with a DVT. The screened patients were older (median 62 vs 55 years, p = 0.0008), but otherwise similar in baseline characteristics. Nonambulatory status, previous history of DVT, lower partial thromboplastin time, and lower hemoglobin level were statistically significant and independent factors associated with positive results of screening for a DVT. Results of screening were positive in only 6.4% of ambulatory patients in contrast to 24.4% of nonambulatory patients, yielding an odds ratio of 4.73 (95% CI 1.88-11.90). All of the patients who had positive screening results underwent preoperative placement of an inferior vena cava filter. CONCLUSIONS Patients requiring surgery for spinal metastases represent a population with unique risks for venous thromboembolism. This study showed a 9.48% incidence of DVT in patients screened preoperatively. The highest rates of preoperative DVT were identified in nonambulatory patients, who were found to have a 4-fold increase in the likelihood of harboring a DVT. Understanding the preoperative thrombotic status may provide an opportunity for early intervention and risk stratification in this critically ill population.

Comparison Between Minimally Invasive Surgery and Conventional Open Surgery for Patients With Spinal Metastasis: A Prospective Propensity Score-Matched Study

STUDY DESIGN

Prospective propensity score-matched study.

OBJECTIVE

To compare the outcomes of minimal invasive surgery (MIS) and conventional open surgery for spinal metastasis patients.

SUMMARY OF BACKGROUND DATA

There is lack of knowledge on whether MIS is comparable to conventional open surgery in treating spinal metastasis.

METHODS

Patients with spinal metastasis requiring surgery from January 2008 to December 2010 in two spine centers were recruited. The demographic, preoperative, operative, perioperative and postoperative data were collected and analyzed. Thirty MIS patients were matched with 30 open surgery patients using propensity score matching technique with a match tolerance of 0.02 based on the covariate age, tumor type, Tokuhashi score, and Tomita score.

RESULTS

Both groups had significant improvements in Eastern Cooperative Oncology Group (ECOG), Karnofsky scores, visual analogue scale (VAS) for pain and neurological status postoperatively. However, the difference comparing the MIS and open surgery group was not statistically significant. MIS group had significantly longer instrumented segments (5.5 ± 3.1) compared with open group (3.8 ± 1.7). Open group had significantly longer decompressed segment (1.8 ± 0.8) than MIS group (1.0 ± 1.0). Open group had significantly more blood loss (2062.1 ± 1148.0 mL) compared with MIS group (1156.0 ± 572.3 mL). More patients in the open group (76.7%) needed blood transfusions (with higher average units of blood transfused) compared with MIS group (40.0%). Fluoroscopy time was significantly longer in MIS group (116.1 ± 63.3 s) compared with open group (69.9 ± 42.6 s). Open group required longer hospitalization (21.1 ± 10.8 days) compared with MIS group (11.0 ± 5.0 days).

CONCLUSION

This study demonstrated that MIS resulted in comparable outcome to open surgery for patients with spinal metastasis but has the advantage of less blood loss, blood transfusions, and shorter hospital stay.

LEVEL OF EVIDENCE

3.

Minimally Invasive Surgical Techniques for Management of Painful Metastatic and Primary Spinal Tumors

Patients with metastatic spinal disease are affected by disabling pain. The treatment of spinal metastases is focused on pain reduction and improvement in quality of life. Until recently, many patients with metastatic spinal disease did not qualify as surgical candidates due to the risks of surgery and length of recovery period. However, recent advances in minimally invasive surgery such as kyphoplasty and vertebroplasty allow patients to safely undergo surgery for pain relief with a short recovery period.

The studies reviewed here suggest that vertebral augmentation is successful in reducing pain and disability scores in patients with painful metastases and multiple myeloma and are a safe modality to provide lasting pain relief. As the use of kyphoplasty and vertebroplasty for treatment of vertebral metastases is becoming more common, new combinations of cement augmentation with other techniques such as percutaneous pedicle screws and radiofrequency ablation are being explored. The implementation of kyphoplasty and vertebroplasty, in conjunction with other minimally invasive surgical techniques as well as nonsurgical modalities, may lead to the best palliative management of cancer patients with spinal metastases and help them ultimately achieve a better quality of life.

Health-related Quality of Life in Patients with Metastatic Spinal Cord Compression

OBJECTIVE

Improvements in cancer treatment have resulted in an increased number of patients with metastatic spinal cord compression (MSCC). Because patients with MSCC often have a limited expected survival time, maintenance of a high functional level and quality of life are important. However, there is limited information about health-related quality of life (HRQoL) in patients with MSCC. The aim of this study was to examine the feasibility of routine assessment of HRQoL based on the Euroqol-5 dimensions (EQ-5D) questionnaire in a cohort of patients consecutively admitted for evaluation of acute symptoms of MSCC.

METHODS

From 1 January to 31 December 2011, 544 patients diagnosed with acute symptoms of MSCC were consecutively enrolled in a cohort study. All patients were evaluated through a centralized referral system at one treatment facility. Data were prospectively registered, the variables age, sex, primary oncologic diagnosis, Tokuhashi Revised score, EQ-5D score and treatment modality being recorded on admission. The study patients were treated conservatively with radiotherapy alone or with surgery and subsequent radiotherapy. The EQ-5D questionnaire was administered on admission (baseline) and 6, 12, 26 and 52 weeks after admission. Response rates, completion rates and HRQoL scores were analyzed by relevant subgroups. Response rates were based on all questionnaires returned regardless of whether or not they had been completed, whereas completion rates were based on fully completed questionnaires (i.e., containing responses to all five questions.

RESULTS

The mean age was 65 years (range, 20-95 years); 57% of the patients were men. The overall response rate to the Euroqol-5 dimensions (EQ-5D) questionnaires was 84% and the overall completion rate 72%. At baseline, mean EQ-5D scores were significantly lower for patients treated with surgery and subsequent radiotherapy 0.28 (95% CI, 0.19-0.36) than for those treated with radiotherapy alone 0.42 (95% CI, 0.38-0.46). At the one-year follow-up, the mean EQ-5D scores had improved to 0.71 (95% CI, 0.64-0.77) for patients treated with surgery and subsequent radiotherapy and 0.63 (95% CI, 0.56-0.70) for patients treated with radiotherapy alone.

CONCLUSIONS

Measurement of HRQoL in patients consecutively admitted for evaluation of acute symptoms of MSCC is feasible and detects significant changes over time between treatment modalities and different strata of expected survival.

Photodynamic therapy in spinal metastases: a qualitative analysis of published results

The current study was to perform qualitative comparison of photodynamic therapy (PDT), based on previously published articles on spinal disease distribution status before and after treatment. Spinal metastasis, the migration of primary cancer cells and establishment of secondary tumors in the spine. We electronically searched CENTRAL (The Cochrane Library 2012), MEDLINE, EMBASE, CINAHL and AMED (from their beginning to December 31, 2012) to identify published studies assessing the effectiveness of PDT in spinal metastases. Our inclusion criteria resulted in only 4 articles, all in mice models. Due to study limitations and sparse data, the quality of evidence for all outcomes was low. Our analyses shows that effects on stereological and mechanical properties observed at the 1-week time point post-PDT are maintained at a longer 6-week time point, with combined PDT + bisphosphonate treatment being the most beneficial in terms of bone enhancement. Additionally, the combination of PDT + radiation therapy also demonstrated significant increases in stereological parameters, suggesting that previous radiation therapy treatment does not preclude the bone-enhancing effects of PDT and in fact may be synergistic in the longer term. The bone-enhancing effects of PDT in combination with conventional treatments, and its ability to destroy metastatic human breast cancer cells within bone, present PDT as an attractive novel treatment for spinal metastasis. The positive results from these preclinical studies might motivate future clinical translation of PDT for spinal metastasis.

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.

Predictive value of pedicle involvement with MRI in spine metastases

OBJECTIVES

The study aimed to retrospectively evaluate the accuracy and value of magnetic resonance imaging (MRI) in predicting pedicle involvement for patients with spine metastases.

METHODS

Forty-five patients with a vertebral metastasis encroaching at least one pedicle were studied using MRI before surgery and regularly after surgery. Patients were categorized on the basis of their numbers of pedicle involvement (Group 1: one pedicle was involved, n = 23; Group 2: two pedicles were involved, n = 22). The diagnostic accuracy was calculated, and comparisons of intraoperative blood loss and recurrence rate between the two groups were performed.

RESULTS

The overall performance of MRI in predicting the pedicle involvement was as follows: accuracy, 94.4%; sensitivity, 95.5%; and specificity, 91.3%. Less intraoperative blood loss was observed for Group 1 compared with Group 2 (1,661 ± 672 ml and 2,173 ± 790 ml, respectively, P = 0.024). Tumor relapse occurred in 8.7% (2/23) of Group 1 and in 22.7% (5/22) of Group 2 with median recurrence free survival time 14 and 9 months, respectively.

CONCLUSIONS

MRI is a reliable approach to assess pedicle involvement. It has potential for use in the evaluation of the clinical characteristics of patients with spine metastases.

A Systematic Review of Clinical Outcomes and Prognostic Factors for Patients Undergoing Surgery for Spinal Metastases Secondary to Breast Cancer

STUDY DESIGN

Review of the literature.

OBJECTIVE

Surgery and cement augmentation procedures are effective palliative treatment of symptomatic spinal metastases. Our objective is to systematically review the literature to describe the survival, prognostic factors, and clinical outcomes of surgery and cement augmentation procedures for breast cancer metastases to the spine.

METHODS

We performed a literature review using PubMed to identify articles that reported outcomes and/or prognostic factors of the breast cancer patient population with spinal metastases treated with any surgical technique since 1990.

RESULTS

The median postoperative survival for metastatic breast cancer was 21.7 months (8.2 to 36 months), the mean rate of any pain improvement was 92.9% (76 to 100%), the mean rate of neurologic improvement was 63.8% (53 to 100%), the mean rate of neurologic decline was 4.1% (0 to 8%), and the local tumor control rate was 92.6% (89 to 100%). Kyphoplasty studies reported a high rate of pain control in selected patients. Negative prognostic variables included hormonal (estrogen and progesterone) and human epidermal growth factor receptor 2 (HER2) receptor refractory tumor status, high degree of axillary lymph node involvement, and short disease-free interval (DFI). All other clinical or prognostic parameters were of low or insufficient strength.

CONCLUSION

With respect to clinical outcomes, surgery consistently yielded neurologic improvements in patients presenting with a deficit with a minimal risk of worsening; however, negative prognostic factors associated with shorter survival following surgery include estrogen receptor/progesterone receptor negativity, HER2 negativity, and a short DFI.

Posterior approaches for symptomatic metastatic spinal cord compression

Surgical interventions for spinal metastasis are commonly performed for mechanical stabilization, pain relief, preservation of neurological function, and local tumor reduction. Although multiple surgical approaches can be used for the treatment of metastatic spinal lesions, posterior approaches are commonly performed. In this study, the role of posterior surgical procedures in the treatment of spinal metastases was reviewed, including posterior laminectomy with and without instrumentation for stabilization, transpedicular corpectomy, and costotransversectomy. A review of the literature from 1980 to 2015 was performed using Medline, as was a review of the bibliographies of articles meeting preset inclusion criteria, to identify studies on the role of these posterior approaches among adults with spinal metastasis. Thirty-four articles were ultimately analyzed, including 1 randomized controlled trial, 6 prospective cohort studies, and 27 retrospective case reports and/or series. Some of the reviewed articles had Level II evidence indicating that laminectomy with stabilization can be recommended for improvement in neurological outcome and reduction of pain in selected patients. However, the use of laminectomy alone should be carefully considered. Additionally, transpedicular corpectomy and costotransversectomy can be recommended with the expectation of improving neurological outcomes and reducing pain in properly selected patients with spinal metastases. With improvements in the treatment paradigms for patients with spinal metastasis, as well as survival, surgical therapy will continue to play an important role in the management of spinal metastasis. While this review presents a window into determining the utility of posterior approaches, future prospective studies will provide essential data to better define the roles of the various options now available to surgeons in treating spinal metastases.