Delphi consensus on stereotactic ablative radiotherapy for oligometastatic and oligoprogressive renal cell carcinoma-a European Society for Radiotherapy and Oncology study endorsed by the European Association of Urology.

The purpose of this European Society for Radiotherapy and Oncology (ESTRO) project, endorsed by the European Association of Urology, is to explore expert opinion on the management of patients with oligometastatic and oligoprogressive renal cell carcinoma by means of stereotactic ablative radiotherapy (SABR) on extracranial metastases, with the aim of developing consensus recommendations for patient selection, treatment doses, and concurrent systemic therapy. A questionnaire on SABR in oligometastatic renal cell carcinoma was prepared by a core group and reviewed by a panel of ten prominent experts in the field. The Delphi consensus methodology was applied, sending three rounds of questionnaires to clinicians identified as key opinion leaders in the field. At the end of the third round, participants were able to find consensus on eight of the 37 questions. Specifically, panellists agreed to apply no restrictions regarding age (25 [100%) of 25) and primary renal cell carcinoma histology (23 [92%] of 25) for SABR candidates, on the upper threshold of three lesions to offer ablative treatment in patients with oligoprogression, and on the concomitant administration of immune checkpoint inhibitor. SABR was indicated as the treatment modality of choice for renal cell carcinoma bone oligometatasis (20 [80%] of 25) and for adrenal oligometastases 22 (88%). No consensus or major agreement was reached regarding the appropriate schedule, but the majority of the poll (54%-58%) retained the every-other-day schedule as the optimal choice for all the investigated sites. The current ESTRO Delphi consensus might provide useful direction for the application of SABR in oligometastatic renal cell carcinoma and highlight the key areas of ongoing debate, perhaps directing future research efforts to close knowledge gaps.

Stereotactic Radiosurgery for Patients with Spinal Metastases from Thyroid Cancer: A 20-Year Experience.

OBJECTIVE: Primary thyroid cancer metastasizing to the spine portends poor survival and low quality of life. Current management strategies continue to evolve. This single-institution retrospective study analyzes outcomes after spinal stereotactic radiosurgery for patients with spinal metastases from thyroid cancer. METHODS: Nineteen patients (median age: 64.5 years) were treated with stereotactic radiosurgery (SRS) for spinal primary thyroid metastases (40 metastases, 47 vertebral levels) between 2003 and 2023. Nineteen (47.5%) lesions had epidural involvement and 20 (50%) lesions were classified as potentially unstable or unstable via the Spinal Instability Neoplastic Score. The median tumor volume per lesion was 33 cc (range: 1.5-153). The median single fraction prescription dose was 20 Gy (range: 12-23.5). RESULTS: The median follow-up period was 15 months (range: 2-40). Five (12.8%) lesions locally progressed at a median of 9 months (range: 4-26) after SRS. The 1-, 2-, and 3-year local tumor control rates per lesion were 90.4%, 83.5%, and 75.9%, respectively. On univariate analysis, age at SRS >70 years (P = 0.05, hazard ratio: 6.86, 95% confidence interval: 1.01-46.7) was significantly correlated with lower rates of local tumor control. The median overall survival was 35 months (range: 2-141). The 1-, 2-, and 3-year overall survival rates were 73.7%, 50.4%, and 43.2%, respectively. For 33 lesions initially associated with pain, patients reported pain improvement (22 lesions, 66.7%), stability (10 lesions, 30.3%), and worsening (1 lesion, 3.0%) after SRS. One patient developed dysphagia 4 months after SRS treatment. CONCLUSIONS: SRS can be utilized as an effective and safe primary and adjuvant treatment option for primary thyroid metastases to the spine.

The role of spine stereotactic radiosurgery for patients with breast cancer metastases.

PURPOSE: Breast cancer that metastasizes to the spine is associated with low quality of life and poor survival. Radiosurgery has an increasing role in this patient population. This single-institution (2003-2023) study analyzes clinical outcomes and prognostic factors for patients who underwent spinal stereotactic radiosurgery (SSRS) for metastatic breast cancer. METHODS: Ninety patients (155 unique breast cancer spinal metastases) were treated with SSRS. The median age was 57 years (range: 35-88), and the median KPS was 80 (range: 40-100). Forty-two (27%) lesions were managed surgically prior to radiosurgery. At SSRS, 75 (48%) lesions impinged or compressed the spinal cord per the epidural spinal cord scale (ESCC). Seventy-nine (51%) lesions were categorized as potentially unstable or unstable by the Spinal Instability Neoplastic Score (SINS). RESULTS: The median follow-up was 15 months (range: 1-183). The median single-session tumor volume was 25.4 cc (range: 2-197), and the median single-fraction prescription dose was 17 Gy (range: 12-25). Seven (5%) lesions locally progressed. The 1-, 2-, and 5-year local control rates were 98%, 97%, and 92%, respectively. The median overall survival (OS) for the cohort was 32 months (range: 2-183). The 1-, 2-, and 5-year OS rates were 72%, 53%, and 30%, respectively. On univariate analysis, KPS ≥ 80 (p = 0.009, HR: 0.51, 95% CI: 0.31-0.84) was associated with improved OS. Patient-reported pain improved (68%), remained stable (29%), or worsened (3%) following radiosurgery. Fifteen (10%) radiation-induced toxicities were reported. CONCLUSIONS: Spinal radiosurgery is a safe and highly effective long-term treatment modality for metastases to the spine that originate from breast cancer.

Surgical intervention ≤ 24 hours versus > 24 hours after injury for the management of acute traumatic central cord syndrome: a systematic review and meta-analysis.

OBJECTIVE: The objective was to evaluate the efficacy, outcomes, and complications of surgical intervention performed within 24 hours (≤ 24 hours) versus after 24 hours (> 24 hours) in managing acute traumatic central cord syndrome (ATCCS). METHODS: Articles pertinent to the study were retrieved from PubMed, Scopus, Web of Science, and Cochrane. The authors performed a systematic review and meta-analysis of treatment procedures and outcomes according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRIMSA) guidelines. RESULTS: Seven articles comprising 488 patients were included, with 188 (38.5%) patients in the ≤ 24-hour group and 300 (61.5%) in the > 24-hour group. Significant differences were not found between groups in terms of demographic characteristics, injury mechanism, spinal cord compression level, neuroimaging features, and the American Spinal Injury Association (ASIA) motor score at admission. Both groups had a similar approach to surgery and steroid administration. The surgical complication rate was significantly higher in the > 24-hour group (4.5%) compared to the ≤ 24-hour group (1.2%) (p = 0.05). Clinical follow-up duration was similar at 12 months (interquartile range 3-36) for both groups (p > 0.99). The ≤ 24-hour group demonstrated a not statistically significant greater improvement in ASIA motor score, with a mean difference of 12 (95% CI -20.7 to 44.6) compared to the > 24-hour group. CONCLUSIONS: The present study indicates potential advantages of early (≤ 24 hours) surgery in ATCCS patients, specifically in terms of lower complication rates. However, further research is needed to confirm these findings and their clinical implications.

Prediction of 30-day and 1-year postoperative complications after balloon-assisted kyphoplasty in the elderly using the Risk Analysis Index.

OBJECTIVE: Vertebral compression fracture (VCF) is the most prevalent fragility fracture. When conservative management fails, patients may undergo balloon-assisted kyphoplasty (BAK). In BAK, an expandable balloon preforms a cavity in the fractured vertebra before injection of bone cement. The aim of this study was to compare outcomes in patients stratified by age and frailty assessed by the Risk Analysis Index (RAI). METHODS: A retrospective analysis of 334 BAK procedures (280 patients) for osteoporotic VCFs at a single institution was performed (2015-2022). Patients with at least 1 year of follow-up were eligible for inclusion. Patient demographics were recorded, including age, sex, BMI, RAI score, tobacco and steroid use, osteoporosis treatments, and bone density. Patients who underwent outpatient surgery were identified, and length of stay (LOS) was obtained for admitted patients. The rates of additional VCFs after kyphoplasty, 30-day and 1-year postoperative complications, and reoperation were identified. RESULTS: The overall rates of additional VCFs, 30-day postoperative complications, 1-year postoperative complications, and reoperation were 16.2%, 5.1%, 12.0%, and 6.3%, respectively. Patients were stratified by age: nonelderly (< 80 years; 220 patients, 263 treated vertebrae) and elderly (≥ 80 years; 60 patients, 71 treated vertebrae). There were no differences in sex (p = 0.593), tobacco use (p = 0.973), chronic steroid use (p = 0.794), treatment for osteoporosis (p = 0.537), bone density (p = 0.056), outpatient procedure (p = 0.273), and inpatient LOS (p = 0.661) between both groups. There were also no differences in the development of additional VCFs (p = 0.862) at an adjacent level (p = 0.739) or remote level (p = 0.814), 30-day and 1-year postoperative complications (p = 0.794 and p = 0.560, respectively), and reoperation rates (p = 0.420). Patients were then analyzed by RAI: nonfrail (RAI score < 30; 203 patients, 243 treated vertebrae) and frail (RAI score ≥ 31; 77 patients, 91 treated vertebrae). There were no differences in tobacco use (p = 0.959), chronic steroid use (p = 0.658), treatment for osteoporosis (p = 0.560), bone density (p = 0.339), outpatient procedure (p = 0.241), inpatient LOS (p = 0.570), and development of additional VCFs (p = 0.773) at an adjacent level (p = 0.390) or remote level (p = 0.689). However, rates of 30-day and 1-year postoperative complications in frail patients more than doubled in comparison with nonfrail patients (p = 0.031 and p = 0.007, respectively), and frail patients trended toward reoperation (p = 0.097). CONCLUSIONS: BAK is a safe treatment in the elderly, and age alone should not be used as an exclusion criterion during patient selection. Frailty, which can be assessed reliably using the RAI, may serve as a better predictor for postoperative complications and reoperation following BAK.

Machine Learning in Spine Surgery: A Narrative Review.

Artificial intelligence and machine learning (ML) can offer revolutionary advances in their application to the field of spine surgery. Within the past 5 years, novel applications of ML have assisted in surgical decision-making, intraoperative imaging and navigation, and optimization of clinical outcomes. ML has the capacity to address many different clinical needs and improve diagnostic and surgical techniques. This review will discuss current applications of ML in the context of spine surgery by breaking down its implementation preoperatively, intraoperatively, and postoperatively. Ethical considerations to ML and challenges in ML implementation must be addressed to maximally benefit patients, spine surgeons, and the healthcare system. Areas for future research in augmented reality and mixed reality, along with limitations in generalizability and bias, will also be highlighted.

Fluorescence-guided resection of intradural spinal tumors: a systematic review and meta-analysis.

Intradural spinal tumors present significant challenges due to involvement of critical motor and sensory tracts. Achieving maximal resection while preserving functional tissue is therefore crucial. Fluorescence-guided surgery aims to improve resection accuracy and is well studied for brain tumors, but its efficacy has not been fully assessed for spinal tumors. This meta-analysis aims to delineate the efficacy of fluorescence guidance in intradural spinal tumor resection. The authors performed a systematic review in four databases. We included studies that have utilized fluorescence agents, 5-aminolevulinic acid (5-ALA) or sodium fluorescein, for the resection of intradural spinal tumors. A meta-analysis was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. A total of 12 studies involving 552 patients undergoing fluorescence-guided intradural spinal tumor resection were included. Meningiomas demonstrated a 98% fluorescence rate and were associated with a homogenous florescence pattern; however, astrocytomas had variable fluorescence rate with pooled proportion of 70%. There was no significant difference in gross total resection (GTR) rates between fluorescein and 5-ALA (94% vs 84%, p = .22). Pre-operative contrast enhancement was significantly associated with intraoperative fluorescence with fluorescein. Intramedullary tumors with positive intraoperative fluorescence were significantly associated with higher GTR rates (96% vs 73%, p = .03). Utilizing fluorescence guidance during intradural spinal tumor resection holds promise of improving intraoperative visualization for specific intradural spinal tumors. Meningiomas and ependymomas have the highest fluorescence rates especially with sodium fluorescein; on the other hand, astrocytomas have variable fluorescence rates with no superiority of either agent. Positive fluorescence of intramedullary tumors is associated with a higher degree of resection.

Safety and Efficacy of Balloon Kyphoplasty for Vertebral Fractures With Posterior Wall Disruption.

BACKGROUND: Percutaneous balloon kyphoplasty (BK) is widely accepted as both a safe and effective method for the treatment of symptomatic benign vertebral compression fractures (VCFs) of the thoracic and lumbar spines. A disruption in the posterior wall of the affected vertebra is often considered to be a relative or an absolute contraindication to BK. This study was performed to determine the safety as well as the efficacy of BK for vertebral body compression fractures associated with posterior wall disruption. METHODS: This was a retrospective, nonrandomized clinical cohort investigation of patients with VCF and posterior wall disruption treated with BK between 2010 and 2018. All cases were performed using a bipedicular technique. Each case was examined for cement leakage, anterior vertebral body height restoration, improvement in pain (determined by VAS) from baseline and 6-week postprocedure, and clinical sequelae from cement leakage. RESULTS: Ninety-eight consecutive patients with 157 VCF levels who underwent BK were evaluated. There was a significant improvement in anterior vertebral height, vertebral wedge angle, and local kyphotic angle in all cases. The mean preoperative VAS improved from 8.7 preprocedure to 2.5 postprocedure (P = .001). There were 14 (9%) cases with asymptomatic cement leakage outside of the vertebral body, and no patients experienced postprocedure neurological symptoms at the 6-week follow up. CONCLUSIONS: BK in the setting of posterior wall disruption was found to be a safe and highly effective treatment for patients with benign compression fractures. Posterior wall disruption should not be considered an absolute contraindication to BK.

Impact of Frailty on Outcomes Following Spine Surgery: A Prospective Cohort Analysis of 668 Patients.

BACKGROUND: With an aging population, elderly patients with multiple comorbidities are more frequently undergoing spine surgery and may be at increased risk for complications. Objective measurement of frailty may predict the incidence of postoperative adverse events. OBJECTIVE: To investigate the associations between preoperative frailty and postoperative spine surgery outcomes including mortality, length of stay, readmission, surgical site infection, and venous thromboembolic disease. METHODS: As part of a system-wide quality improvement initiative, frailty assessment was added to the routine assessment of patients considering spine surgery beginning in July 2016. Frailty was assessed with the Risk Analysis Index (RAI), and patients were categorized as nonfrail (RAI 0-29) or prefrail/frail (RAI ≥ 30). Comparisons between nonfrail and prefrail/frail patients were analyzed using Fisher's exact test for categorical data or by Wilcoxon rank sum tests for continuous data. RESULTS: From August 2016 through September 2018, 668 patients (age of 59.5 ± 13.3 yr) had a preoperative RAI score recorded and underwent scheduled spine surgery. Prefrail and frail patients suffered comparatively higher rates of mortality at 90 d (1.9% vs 0.2%, P < .05) and 1 yr (5.1% vs 1.2%, P < .01) from the procedure date. They also had longer in-hospital length of stay (LOS) (3.9 d ± 3.6 vs 3.1 d ± 2.8, P < .001) and higher rates of 60 d (14.6% vs 8.2%, P < .05) and 90 d (15.8% vs 9.8%, P < .05) readmissions. CONCLUSION: Preoperative frailty, as measured by the RAI, was associated with an increased risk of readmission and 90-d and 1-yr mortality following spine surgery. The RAI can be used to stratify spine patients and inform preoperative surgical decision making.

Causes of hospital readmissions within 7 days from the neurosurgical service of a quaternary referral hospital.

BACKGROUND: Evaluation of readmission rates as a proxy metric of health-care quality in neurological surgery has grown to become a prevalent area of investigation in the last several years. Significant attention has been paid to 30-day readmission rates due to the financial incentive to health-care providers following the enforcement of the penalties created by the Affordable Care Act. However, relatively little attention has been paid to patients readmitted within 7 days of discharge to large quaternary neurological surgery services. This study was conducted to examine the causes and unique characteristics of 7-day readmission rates from a neurosurgical service at a large quaternary referral hospital. METHODS: A retrospective observational analysis of all 7-day readmissions to the neurosurgical surgery service of the University of Pittsburgh Medical Center, Presbyterian Hospital from August 2017 to June 2019, was performed. Patients were organized into seven categories based on their primary reason for readmission: scheduled surgeries, infection, pain, altered mental status or seizures, general postoperative complications, complications directly resulting from a neurosurgical intervention, and unrelated reasons. Demographic information, the time between initial discharge and subsequent readmission, and discharge disposition were also recorded. RESULTS: Of 5274 discharges, 258 patients (4.9%) were readmitted within 7 days (55.0% male; mean age 60 years of age). Two-thirds of patients readmitted initially underwent care for cranial pathologies (57% of 258 patients) as opposed to a third for spine pathologies (33% of 258 patients). Complications that directly arose from the neurosurgical intervention (e.g., shunt infection or misplacement, and hardware misplacement) represented 18.9% of total readmission, while general postoperative complications (e.g., urinary tract infection) accounted for 15.1% of total readmission, in which all together were slightly greater than a third of readmissions. Seizures or altered mental status led to less than a fifth of readmissions (17.0%), followed by readmissions from unrelated diagnosis or miscellaneous reasons (17.0%) and scheduled surgeries (13.1%). Taken together, surgical site infections (9.7%) and postoperative pain (9.3%) accounted for 9.7% and 9.3 % of readmissions, respectively. CONCLUSION: Approximately 5% of patients discharged in a single year from our quaternary referral center were readmitted within 7-days. Approximately 90% of all 7-day readmissions were unplanned, with one-third resulting directly from perioperative complications. Further investigation to better understand this acutely vulnerable yet previously overlooked population may guide focused efforts to increase the quality of neurosurgical patient care.

Single fraction radiosurgery, fractionated radiosurgery, and conventional radiotherapy for spinal oligometastasis (SAFFRON): A systematic review and meta-analysis.

BACKGROUND AND PURPOSE: To perform a systematic review/meta-analysis of outcomes for patients with spinal metastases treated with stereotactic radiosurgery (SRS) (either single-fraction (SF-SRS) or multiple-fraction (MF-SRS)) or conventional radiotherapy (RT). MATERIALS AND METHODS: Thirty-seven studies were identified. Primary outcomes were 1-year local control (LC) and acute/late grade 3-5 toxicities (including vertebral compression fractures (VCF)). Weighted random effects meta-analyses using the DerSimonian and Laird methods and meta-regressions were conducted to characterize and compare effect sizes. Mixed effects regression models were used in dose analyses. RESULTS: A total of 3237 patients with 4911 lesions were included; 43.8%, 19.7%, and 36.5% of lesions received SF-SRS, MF-SRS, or RT, respectively. SF-SRS resulted in improved 1-year LC (92.9% (95% CI: 86.4-97.4%); p = 0.007) compared to RT (81.0% (95% CI: 69.2-90.5%)) with no difference between MF-SRS (82.1%; p = 0.86) and RT. On subgroup analysis of de novo metastases, superior 1-year LC following SF-SRS (95.5% (95% CI: 87.4-99.6%)) was maintained compared to RT (83.6% (95% CI: 70.4-93.5%); p = 0.007). A 4.7% increase in LC was noted for each 10 Gy10 increase in biologically effective dose (BED10, assuming an alpha/beta = 10) with SRS (p < 0.001). No difference in toxicities were found between SF-SRS (0.4%), MF-SRS (0.2%), or RT (0%). Higher VCF rates were noted following SF-SRS (19.5%) vs. MF-SRS (9.6%; p = 0.039)) with no correlation between dose and VCF rates. CONCLUSION: SF-SRS resulted in superior LC with a roughly 5% LC benefit for every 10 Gy10 increase in BED10 with higher VCF rates compared to MF-SRS. If LC is the goal of treatment, then SRS may be a preferred treatment modality. However, these results are hypothesis-generating, and prospective randomized clinical trials are indicated to definitively address the question of whether SRS results in improved LC compared to RT.

Stereotactic Radiosurgery for Benign Spinal Tumors.

Benign spinal tumors are rare clinical conditions, including meningiomas, schwannomas, and neurofibromas. Although these tumors are usually treated with open surgical resection, spinal stereotactic radiosurgery may be a safe and effective alternative to surgery in selected patients.

Radiosurgery to the spinal dorsal root ganglion induces fibrosis and inhibits satellite glial cell activation while preserving axonal neurotransmission.

OBJECTIVE: Stereotactic radiosurgery (SRS) has been used to treat trigeminal neuralgia by targeting the cisternal segment of the trigeminal nerve, which in turn triggers changes in the gasserian ganglion. In the lumbar spine, the dorsal root ganglion (DRG) is responsible for transmitting pain sensitivity and is involved in the pathogenesis of peripheral neuropathic pain. Therefore, radiosurgery to the DRG might improve chronic peripheral pain. This study evaluated the clinical and histological effects of high-dose radiosurgery to the DRG in a rodent model. METHODS: Eight Sprague-Dawley rats received either 40- or 80-Gy SRS to the fifth and sixth lumbar DRGs using the Leksell Gamma Knife Icon. Animals were euthanized 3 months after treatment, and the lumbar spine was dissected and taken for analysis. Simple histology was used to assess collagen deposition and inflammatory response. GFAP, Neu-N, substance P, and internexin were used as a measure of peripheral glial activation, neurogenesis, pain-specific neurotransmission, and neurotransmission in general, respectively. The integrity of the spinothalamic tract was assessed by means of the von Frey test. RESULTS: The animals did not exhibit any signs of motor or sensory deficits during the experimentation period. Edema, fibrosis, and vascular sclerotic changes were present on the treated, but not the control, side. SRS reduced the expression of GFAP without affecting the expression of Neu-N, substance P, or internexin. The von Frey sensory perception elicited equivalent results for the control side and both radiosurgical doses. CONCLUSIONS: SRS did not alter sensory or motor function but reduced the activation of satellite glial cells, a pathway for DRG-mediated pain perpetuation. Radiosurgery provoked changes equivalent to the effects of focal radiation on the trigeminal ganglion after SRS for trigeminal neuralgia, suggesting that radiosurgery could be successful in relieving radiculopathic pain.

A New Piece of the Puzzle to Understand Cervical Sagittal Alignment: Utilizing a Novel Angle δ to Describe the Relationship among T1 Vertebral Body Slope, Cervical Lordosis, and Cervical Sagittal Alignment.

Cervical alignment has become increasingly important in the planning of spine surgery. A relationship between the slope of T1 (T1S), the cervical lordosis (CL), and the overall cervical sagittal vertical axis (cSVA) has previously been demonstrated, but the exact nature of this relationship is poorly understood. In this study, we derive theoretical and empirical equations to better understand how T1S and CL affect cSVA. The first equation was developed on a theoretical basis using inherent trigonometric relationships of the cervical spine. By treating the cervical spine as the arc of a circumference, and by taking into account the cervical height (CH), the geometric relationship between theT1S, CL, and cSVA was described via a trigonometric identity utilizing a novel angle δ subtended by the CH and cSVA (δ = T1S-CL/2). The second equation was developed on an empiric basis by performing a multiple linear regression on data obtained from a retrospective review of a large multicenter deformity database. The theoretical equation determined that the value of cSVA could be expressed as: $cSVA\ = \ CH*{\rm{tan}}( {\pi /180*( {T1S - CL/2} )} )$. The empirical equation determined that value of cSVA could be expressed as: $cSVA=({1.1*T1} )\ - ( {0.43*CL} ) + 6.69$. In both, the sagittal alignment of the head over the shoulders is directly proportional to the T1S and inversely proportional to CL/2. These 2 equations may allow surgeons to better understand how the CL compensates for the T1S, to accurately predict the postoperative cSVA, and to customize cervical interbody grafts by taking into consideration each individual patient's specific cervical spine parameters.

Spinal metastasis: diagnosis, management and follow-up.

Spine metastatic disease is an increasingly common occurrence in cancer patients due to improved patient survival. Close proximity of the bony spinal column to the spinal cord limits many conventional treatments for metastatic disease. In the past decade, we have witnessed dramatic advancements in therapies, with improvements in surgical techniques and recent adoption of spine stereotactic radiotherapy techniques leading to improved patient outcomes. Multidisciplinary approaches to patient evaluation, treatment and follow-up are essential. Imaging plays an ever increasing role in disease detection, pre-treatment planning and assessment of patient outcomes. It is important for the radiologist to be familiar with imaging algorithms, best practices for surgery and/or radiotherapy and imaging findings in the post-treatment period that may indicate disease recurrence. In this review, we present a multidisciplinary discussion of spine metastases, with specific focus on pre-treatment imaging, planning, current treatment approaches, and post-treatment assessment.

Craniometrical imaging and clinical findings of adult Chiari malformation type 1 before and after posterior fossa decompression surgery with duraplasty.

Background: Posterior fossa decompression both with and without duraplasty are accepted treatments for symptomatic adult patients with Chiari Malformations Type 1 (CM-1). There is still debate of the superiority of one technique over the other. The purpose of this study was to determine the clinical and craniometrical imaging outcomes of a series of patients who underwent posterior fossa decompression with duraplasty. Materials and methods: All adult patients with symptomatic CM-1 operated at a single institution with a minimum of 6 months follow-up were enrolled prospectively. Clinical outcomes and craniometrical parameters based upon MR imaging pre- and post-surgery were analyzed. Results: A series of 33 consecutive patients who met the inclusion criteria were enrolled; mean age of 33.93 ± 10 years (range 14-56 years). The most common preoperative complaint was headache. The most common clinical sign was sensory dysfunction which was relieved or improved in 63% of patients. The mean syringomyelia size had a significant reduction after the surgery (p = .01). The mean tonsillar descent also had significant reduction (p = .00). The mean McRae line length before the surgery and after that were 33.4 and 53.1 mm respectively that this change was not statistically significant (p = .42). The odontoid process parameters had no significant changes after surgery. Conclusions: Posterior fossa decompression surgery with duraplasty can improve both clinical and imaging outcomes such as syringomyelia size and tonsillar descent for patients with symptomatic CM-1. However, no significant difference was found in craniometrical parameters before and after the surgery.

Risk-to-Benefit Ratio of Venous Thromboembolism Prophylaxis for Neurosurgical Procedures at a Quaternary Referral Center.

BACKGROUND: Pharmacological prophylaxis for venous thromboembolism (VTE) in the neurosurgical population is still a matter of debate, as the risk-to-benefit ratio is not well defined. OBJECTIVE: To further evaluate the risk-to-benefit ratio of VTE prophylaxis (VTEP) for all neurosurgical procedures. METHODS: A prospective evaluation was performed after the initiation of a VTEP protocol for 11 436 patients undergoing neurosurgical procedures over 24 mo. Unless a bleeding complication was present, 5000 international units of subcutaneous heparin every 8 h was ordered on postoperative day (POD) 1 for spine, POD2 for cranial, and by POD4 for subdural, intracerebral, and epidural hematoma cases. Incidence of VTE and any subsequent bleeding complications were noted. RESULTS: A total of 70 VTEs (0.6% overall) were documented (28 deep vein thrombosis, 42 pulmonary embnolism). The highest rates of VTE were associated with deformity (6.7%); open cerebrovascular (6.5%); subdural, intracerebral, and epidural hematoma (3.2%); spinal trauma (2.4%); and craniotomy for tumor (1.6%) cases. Seven cases of deep vein thrombosis progressed to pulmonary embolisms, and 66 of 70 VTEs occurred while on pharmacological VTEP. Fifty-four bleeding complications occurred on or after POD2 following initiation of VTEP. These bleeding complications consisted of any new clinically or radiographically observed hemorrhages. Twenty-eight of the 54 delayed bleeding complications required operative intervention with 1 mortality. Forty-five patients were on anticoagulation when the initial bleeding event occurred. Overall, an estimated 0.5% incidence of delayed bleeding complications was noted with 99.4% of patients within the study cohort remaining VTE free. CONCLUSION: This VTEP protocol was determined to afford a good risk-to-benefit ratio for a wide variety of neurosurgical procedures.

Histopathological Findings After Reirradiation Compared to First Irradiation of Spinal Bone Metastases With Stereotactic Body Radiotherapy: A Cohort Study.

BACKGROUND: Stereotactic body radiotherapy (SBRT) of the spine provides superior tumor control, but vertebral compression fractures are increased and the pathophysiological process underneath is not well understood. Data on histopathological changes, particularly after salvage SBRT (sSBRT) following conventional irradiation, are scarce. OBJECTIVE: To investigate surgical specimens after sSBRT and primary SBRT (pSBRT) regarding histopathological changes. METHODS: We assessed 704 patients treated with spine SBRT 2006 to 2012. Thirty patients underwent salvage surgery; 23 histopathological reports were available. Clinical and histopathological findings were analyzed for sSBRT (69.6%) and pSBRT (30.4%). RESULTS: Mean time to surgery after sSBRT/pSBRT was 8.3/10.3 mo (P = .64). Reason for surgery included pain (sSBRT/pSBRT: 12.5%/71.4%, P = .25), fractures (sSBRT/pSBRT: 37.5%/28.6%, P = .68), and neurological symptoms (sSBRT/pSBRT: 68.8%/42.9%, P = .24). Radiological tumor progression after sSBRT/pSBRT was seen in 71.4%/42.9% (P = .2). Most specimens displayed viable/proliferative tumor (sSBRT/pSBRT: 62.5%/71.4%, P = .68 and 56.3%/57.1%, P = .97). Few specimens showed soft tissue necrosis (sSBRT/pSBRT: 20%/28.6%, P = .66), osteonecrosis (sSBRT/pSBRT: 14.3%/16.7%, P = .89), or bone marrow fibrosis (sSBRT/pSBRT: 42.9%/33.3%, P = .69). Tumor bed necrosis was more common after sSBRT (81.3%/42.9%, P = .066). Radiological tumor progression correlated with viable/proliferative tumor (P = .03/P = .006) and tumor bed necrosis (P = .03). Fractures were increased with bone marrow fibrosis (P = .07), but not with osteonecrosis (P = .53) or soft tissue necrosis (P = .19). Neurological symptoms were common with radiological tumor progression (P = .07), but not with fractures (P = .18). CONCLUSION: For both, sSBRT and pSBRT, histopathological changes were similar. Neurological symptoms were attributable to tumor progression and pathological fractures were not associated with osteonecrosis or tumor progression.

Evaluation of Clinical and Histologic Effects of High-Dose Radiosurgery on Rat Dorsal Root Ganglion.

BACKGROUND: Stereotactic radiosurgery (SRS) is an effective technique to create lesions of the trigeminal nerve to treat refractory trigeminal neuralgia. In the lumbar spine, the dorsal root ganglion (DRG) contains the body of the sensory neurons responsible for pain sensitivity. Neuromodulation of the DRG might therefore improve chronic peripheral pain. This study was performed to determine the feasibility, clinical, and histologic effects of delivering high-dose SRS targeted to the lumbar DRG in a rat model. METHODS: Four Sprague Dawley male rats underwent 80 Gy maximum-dose single-fraction SRS to the left L5 and L6 DRG using the Leksell Gamma Knife Icon (Elekta, Atlanta, Georgia, USA). The right L5 and L6 DRGs served as controls. The animals were evaluated for motor and sensory deficits every 2 weeks and were sacrificed at 3 and 6 months after SRS. Common histologic techniques were used to assess for fibrosis and demyelination at the target levels. RESULTS: No detectable motor or sensory deficits were seen in any animal. Histologic changes including fibrosis and loss of myelin were noted to the left L5 and L6 DRGs, but not the right side control DRGs. Fibrotic changes within the vertebral body were also evident on the treated sides of the vertebral bodies. CONCLUSIONS: We were able to detect a demyelinating response from SRS delivered to the DRG in rats. Because such changes mimic those seen after trigeminal SRS in experimental animals, we hypothesize that radiosurgery may be a potential option in chronic spinal radicular pain amenable to neuromodulation.

Stereotactic body radiation therapy for benign spine tumors: is dose de-escalation appropriate?

OBJECTIVE Akin to the nonoperative management of benign intracranial tumors, stereotactic body radiation therapy (SBRT) has emerged as a nonoperative treatment option for noninfiltrative primary spine tumors such as meningioma and schwannoma. The majority of initial series used higher doses of 16-24 Gy in 1-3 fractions. The authors hypothesized that lower doses (such as 12-13 Gy in 1 fraction) might provide an efficacy similar to that found with the dose de-escalation commonly used for intracranial radiosurgery to treat acoustic neuroma or meningioma and with a lower risk of toxicity. METHODS The authors identified 38 patients in a prospectively maintained institutional radiosurgery database who were treated with definitive SBRT for a total of 47 benign primary spine tumors between 2004 and 2016. SBRT consisted of 9-21 Gy in 1-3 fractions using the CyberKnife (n = 11 [23%]), Synergy S (n = 21 [45%]), or TrueBeam (n = 15 [32%]) radiosurgery platform. For a comparison of SBRT doses, patients were dichotomized into 1 of 2 groups (low-dose or high-dose SBRT) using a cutoff biologically effective dose (BED10Gy) of 30 Gy. Tumor control was calculated from the date of SBRT to the last follow-up using Kaplan-Meier survival analysis, with comparisons between groups completed using a log-rank method. To account for potential indication bias, a propensity score analysis was completed based on the conditional probabilities of SBRT dose selection. Toxicity was graded using Common Terminology Criteria for Adverse Events version 4.0 with a focus on grade 3+ toxicity and the incidence of pain flare. RESULTS For the 38 patients, the most common histological findings were meningioma (15 patients), schwannoma (13 patients), and hemangioblastoma (7 patients). The median age at SBRT was 58 years (range 25-91 years). The 47 treated lesions were located in the cervical (n = 18), thoracic (n = 19), or lumbosacral (n = 10) spine. Five (11%) lesions were lost to follow-up after SBRT. The median follow-up duration for the remaining 42 lesions was 54 months (range 1.2-133 months). Six (16%) patients (with a total of 8 lesions) experienced pain flare after SBRT; no significant predictor of pain flare was identified. No grade 3+ acute- or late-onset complication was noted. The 5-year local control rate was 76% (95% CI 61%-91%). No significant difference in local control according to dose, fractionation, previous radiation, surgery, tumor histology, age, treatment platform, planning target volume, or spine level treated was found. The 5-year local control rates for low- and high-dose treatments were 73% (95% CI 53%-93%) and 83% (95% CI 61%-100%) (p = 0.52). In propensity score-adjusted multivariable analysis, no difference in local control was identified (HR 0.30, 95% CI 0.02-5.40; p = 0.41). CONCLUSIONS Long-term follow-up of patients treated with SBRT for benign spinal lesions revealed no significant difference between low-dose (BED10Gy ≤ 30) and high-dose SBRT in local control, pain-flare rate, or long-term toxicity.