Safety and Efficacy of Balloon-Assisted Kyphoplasty Followed by Stereotactic Body Radiation Therapy for Pathological Fractures.

BACKGROUND AND OBJECTIVES: In patients experiencing pain secondary to pathological compression fractures, balloon-assisted kyphoplasty and subsequent stereotactic body radiation therapy (SBRT) may allow for restoration of vertebral height and irradiation of the underlying malignancy to control local disease progression. The aim of this study was to evaluate the safety and efficacy of kyphoplasty treatment before SBRT in patients with spinal metastases and benign tumors. METHODS: An analysis of a prospectively collected database of 70 patients and 75 metastatic and benign spinal lesions that underwent kyphoplasty before SBRT at a single institution (2002-2023) was conducted. Patient characteristics were recorded, including treatment history, dosimetry and fractionation schedule, pain outcomes, local control (LC), and overall survival. The Bilsky score and Spinal Instability Neoplastic Score were calculated to assess epidural involvement and spinal stability, respectively. RESULTS: The median time from kyphoplasty to SBRT was 29 days (range: 2-159). Seventy-two lesions (96%) were managed with single-fraction SBRT and 3 lesions (4%) with a multifraction regimen. The median single-fraction prescription dose was 20 Gy (range: 12-25) delivered to a median tumor volume of 35.1 cc (range: 2.2-160). After a median follow-up period of 9 months (range: 1-201), 6 lesions (8%) locally progressed. Pain was reported to improve or remain stable for most patients (88%). The LC rate was 88% at 6 months, 1 year, and 2 years. No prognostic factors were significantly associated with LC. The median overall survival was 11 months (range: 1-201) after radiosurgery. There were no reports of cement extravasation or radiation-induced neurological deficit. Two acute pain flares (3%) were reported 1 and 3 months after radiosurgery. CONCLUSION: The combined kyphoplasty and SBRT treatment paradigm can be used to treat patients with painful pathological compression fractures. Long-term LC and patient-reported improvement in pain were observed without the morbidity associated with open surgery.

Development of Symptomatic Adjacent and Remote Level Compression Fractures Following Balloon-assisted Kyphoplasty in a Series of 1,318 Patients.

BACKGROUND: Balloon-assisted kyphoplasty (BAK) is a minimally invasive procedure to treat vertebral compression fractures (VCF). BAK not only restores vertebral height and corrects kyphotic deformity by cement augmentation, but it also may alter spinal biomechanics, leading to subsequent adjacent level VCFs. OBJECTIVES: This study aims to investigate the timing, location, and incidence of new VCFs following BAK and identify the risk factors associated with their occurrence. STUDY DESIGN: Single-institution observational study. METHODS: A prospectively collected cohort of 1,318 patients who underwent BAK by a single-surgeon from 2001 through 2022 was analyzed. The patients had pain that was unresponsive to nonsurgical management and a VCF secondary to osteoporosis, trauma, or neoplasm. The time between the index and subsequent fracture, fracture level, number of initial fractures, age, body mass index (BMI), tobacco use, and chronic corticosteroid use were recorded. RESULTS: Of 1,318 patients, 204 (15.5%) patients underwent a second BAK procedure an average of 373 days following BAK (range: 2-3,235 days). Third, fourth, and fifth procedures were less common (45, 12, and 6 patients, respectively). A total of 142 patients (69.6%) developed a subsequent fracture adjacent to the index level; adjacent and remote level fractures developed at different times (mean: 282 vs 581 days, P = 0.001). Patients treated for multiple VCFs in a single surgery were more likely to develop subsequent VCFs (P = 0.024) and at adjacent levels (P = 0.007). Subsequent VCFs were associated with older age (P < 0.001), women (P = 0.045), osteoporosis (P < 0.001), and chronic corticosteroid use (P < 0.001). A subgroup analysis of 812 (61.6%) patients who underwent BAK for degenerative indications revealed that osteoporosis (b = 0.09; 95% CI, 0.03-0.16; P = 0.005) and chronic corticosteroid use (b = 0.06; 95% CI, 0-0.11; P = 0.055) were associated with adjacent level fracture. For the entire cohort, almost every patient treated for both a thoracic and lumbar fracture (92.3%) developed an adjacent level second fracture (P = 0.005). LIMITATIONS: The true incidence of post-BAK fractures may be underestimated as surveillance is not routine in asymptomatic or osteoporotic patients. CONCLUSIONS: Symptomatic post-BAK VCFs are infrequent and may occur long after the initial procedure. Nearly two-thirds of subsequent fractures in our study occurred adjacent to the initially treated level; almost every patient who suffered thoracic and lumbar fractures at the same time developed an adjacent level second fracture. Additionally, osteoporosis and chronic corticosteroid use were associated with adjacent level fractures in patients who underwent surgery for degenerative indications.

Analysis of injected cement volume and clinical outcomes following balloon-assisted kyphoplasty in a series of 368 patients.

OBJECTIVE: Balloon-assisted kyphoplasty (BAK) is a modified vertebroplasty technique developed to treat vertebral compression fractures (VCFs) secondary to osteoporosis. This study investigates the association between injected cement volume and the development of subsequent VCFs after BAK. METHODS: A retrospective analysis of 368 patients who underwent BAK at a single institution was performed from 2001 to 2021. Inclusion was defined by at least 2 years of follow-up. Clinical characteristics and outcomes following BAK, including subsequent fractures at adjacent and remote levels, were identified. Patients that underwent a thoracic BAK were stratified by injected cement volume: below or equal to the median (≤ 6.0 mL, 265 vertebrae) or above the median (> 6.0 mL, 144 vertebrae). Patients that underwent a lumbar BAK were similarly stratified: below or equal to the median (≤ 8.0 mL, 233 vertebrae) or above the median (>8.0 mL, 160 vertebrae). RESULTS: A total of 802 vertebrae were treated. The average volume of cement was recorded in the thoracic (6.2 ± 1.9 mL) and lumbar (7.8 ± 1.8 mL) vertebrae. In the thoracic spine, vertebrae that were injected with > 6.0 mL of cement underwent a greater change in local kyphotic angle (P = 0.0001) and were more likely to develop adjacent-level VCFs (P = 0.032) after kyphoplasty. Univariate analysis did not elucidate any additional risk factors. There were no statistical differences in clinical outcomes between the three groups of lumbar vertebrae. CONCLUSIONS: Larger volumes of injected cement were associated with a greater change in local kyphosis and subsequent adjacent-level fractures after BAK in the thoracic spine. This association was not found in the lumbar spine. Close attention to injected cement volumes must be made in the thoracic spine and patients who undergo significant kyphotic correction should be carefully observed postoperatively.

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.

Usefulness and Accuracy of Artificial Intelligence Chatbot Responses to Patient Questions for Neurosurgical Procedures.

BACKGROUND AND OBJECTIVES: The Internet has become a primary source of health information, leading patients to seek answers online before consulting health care providers. This study aims to evaluate the implementation of Chat Generative Pre-Trained Transformer (ChatGPT) in neurosurgery by assessing the accuracy and helpfulness of artificial intelligence (AI)-generated responses to common postsurgical questions. METHODS: A list of 60 commonly asked questions regarding neurosurgical procedures was developed. ChatGPT-3.0, ChatGPT-3.5, and ChatGPT-4.0 responses to these questions were recorded and graded by numerous practitioners for accuracy and helpfulness. The understandability and actionability of the answers were assessed using the Patient Education Materials Assessment Tool. Readability analysis was conducted using established scales. RESULTS: A total of 1080 responses were evaluated, equally divided among ChatGPT-3.0, 3.5, and 4.0, each contributing 360 responses. The mean helpfulness score across the 3 subsections was 3.511 ± 0.647 while the accuracy score was 4.165 ± 0.567. The Patient Education Materials Assessment Tool analysis revealed that the AI-generated responses had higher actionability scores than understandability. This indicates that the answers provided practical guidance and recommendations that patients could apply effectively. On the other hand, the mean Flesch Reading Ease score was 33.5, suggesting that the readability level of the responses was relatively complex. The Raygor Readability Estimate scores ranged within the graduate level, with an average score of the 15th grade. CONCLUSION: The artificial intelligence chatbot's responses, although factually accurate, were not rated highly beneficial, with only marginal differences in perceived helpfulness and accuracy between ChatGPT-3.0 and ChatGPT-3.5 versions. Despite this, the responses from ChatGPT-4.0 showed a notable improvement in understandability, indicating enhanced readability over earlier versions.

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.

Supraspinal control of motoneurons after paralysis enabled by spinal cord stimulation.

Spinal cord stimulation (SCS) restores motor control after spinal cord injury (SCI) and stroke. This evidence led to the hypothesis that SCS facilitates residual supraspinal inputs to spinal motoneurons. Instead, here we show that SCS does not facilitate residual supraspinal inputs but directly triggers motoneurons action potentials. However, supraspinal inputs can shape SCS-mediated activity, mimicking volitional control of motoneuron firing. Specifically, by combining simulations, intraspinal electrophysiology in monkeys and single motor unit recordings in humans with motor paralysis, we found that residual supraspinal inputs transform subthreshold SCS-induced excitatory postsynaptic potentials into suprathreshold events. We then demonstrated that only a restricted set of stimulation parameters enables volitional control of motoneuron firing and that lesion severity further restricts the set of effective parameters. Our results explain the facilitation of voluntary motor control during SCS while predicting the limitations of this neurotechnology in cases of severe loss of supraspinal axons.

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.

Neural population dynamics reveals disruption of spinal circuits' responses to proprioceptive input during electrical stimulation of sensory afferents.

While neurostimulation technologies are rapidly approaching clinical applications for sensorimotor disorders, the impact of electrical stimulation on network dynamics is still unknown. Given the high degree of shared processing in neural structures, it is critical to understand if neurostimulation affects functions that are related to, but not targeted by, the intervention. Here, we approach this question by studying the effects of electrical stimulation of cutaneous afferents on unrelated processing of proprioceptive inputs. We recorded intraspinal neural activity in four monkeys while generating proprioceptive inputs from the radial nerve. We then applied continuous stimulation to the radial nerve cutaneous branch and quantified the impact of the stimulation on spinal processing of proprioceptive inputs via neural population dynamics. Proprioceptive pulses consistently produce neural trajectories that are disrupted by concurrent cutaneous stimulation. This disruption propagates to the somatosensory cortex, suggesting that electrical stimulation can perturb natural information processing across the neural axis.

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.

SUPRASPINAL CONTROL OF MOTONEURONS AFTER PARALYSIS ENABLED BY SPINAL CORD STIMULATION.

Spinal cord stimulation (SCS) restores motor control after spinal cord injury (SCI) and stroke. This evidence led to the hypothesis that SCS facilitates residual supraspinal inputs to spinal motoneurons. Instead, here we show that SCS does not facilitate residual supraspinal inputs but directly triggers motoneurons action potentials. However, supraspinal inputs can shape SCS-mediated activity, mimicking volitional control of motoneuron firing. Specifically, by combining simulations, intraspinal electrophysiology in monkeys and single motor unit recordings in humans with motor paralysis, we found that residual supraspinal inputs transform subthreshold SCS-induced excitatory postsynaptic potentials into suprathreshold events. We then demonstrated that only a restricted set of stimulation parameters enables volitional control of motoneuron firing and that lesion severity further restricts the set of effective parameters. Our results explain the facilitation of voluntary motor control during SCS while predicting the limitations of this neurotechnology in cases of severe loss of supraspinal axons.

Stereotactic Radiosurgery vs Conventional Radiotherapy for Localized Vertebral Metastases of the Spine: Phase 3 Results of NRG Oncology/RTOG 0631 Randomized Clinical Trial.

Importance: Spine metastasis can be treated with high-dose radiation therapy with advanced delivery technology for long-term tumor and pain control. Objective: To assess whether patient-reported pain relief was improved with stereotactic radiosurgery (SRS) as compared with conventional external beam radiotherapy (cEBRT) for patients with 1 to 3 sites of vertebral metastases. Design, Setting, and Participants: In this randomized clinical trial, patients with 1 to 3 vertebral metastases were randomized 2:1 to the SRS or cEBRT groups. This NRG 0631 phase 3 study was performed as multi-institutional enrollment within NRG Oncology. Eligibility criteria included the following: (1) solitary vertebral metastasis, (2) 2 contiguous vertebral levels involved, or (3) maximum of 3 separate sites. Each site may involve up to 2 contiguous vertebral bodies. A total of 353 patients enrolled in the trial, and 339 patients were analyzed. This analysis includes data extracted on March 9, 2020. Interventions: Patients randomized to the SRS group were treated with a single dose of 16 or 18 Gy (to convert to rad, multiply by 100) given to the involved vertebral level(s) only, not including any additional spine levels. Patients assigned to cEBRT were treated with 8 Gy given to the involved vertebra plus 1 additional vertebra above and below. Main Outcomes and Measures: The primary end point was patient-reported pain response defined as at least a 3-point improvement on the Numerical Rating Pain Scale (NRPS) without worsening in pain at the secondary site(s) or the use of pain medication. Secondary end points included treatment-related toxic effects, quality of life, and long-term effects on vertebral bone and spinal cord. Results: A total of 339 patients (mean [SD] age of SRS group vs cEBRT group, respectively, 61.9 [13.1] years vs 63.7 [11.9] years; 114 [54.5%] male in SRS group vs 70 [53.8%] male in cEBRT group) were analyzed. The baseline mean (SD) pain score at the index vertebra was 6.06 (2.61) in the SRS group and 5.88 (2.41) in the cEBRT group. The primary end point of pain response at 3 months favored cEBRT (41.3% for SRS vs 60.5% for cEBRT; difference, -19 percentage points; 95% CI, -32.9 to -5.5; 1-sided P = .99; 2-sided P = .01). Zubrod score (a measure of performance status ranging from 0 to 4, with 0 being fully functional and asymptomatic, and 4 being bedridden) was the significant factor influencing pain response. There were no differences in the proportion of acute or late adverse effects. Vertebral compression fracture at 24 months was 19.5% with SRS and 21.6% with cEBRT (P = .59). There were no spinal cord complications reported at 24 months. Conclusions and Relevance: In this randomized clinical trial, superiority of SRS for the primary end point of patient-reported pain response at 3 months was not found, and there were no spinal cord complications at 2 years after SRS. This finding may inform further investigation of using spine radiosurgery in the setting of oligometastases, where durability of cancer control is essential. Trial Registration: ClinicalTrials.gov Identifier: NCT00922974.

POTENTIATION OF CORTICO-SPINAL OUTPUT VIA TARGETED ELECTRICAL STIMULATION OF THE MOTOR THALAMUS.

Cerebral white matter lesions prevent cortico-spinal descending inputs from effectively activating spinal motoneurons, leading to loss of motor control. However, in most cases, the damage to cortico-spinal axons is incomplete offering a potential target for new therapies aimed at improving volitional muscle activation. Here we hypothesized that, by engaging direct excitatory connections to cortico-spinal motoneurons, stimulation of the motor thalamus could facilitate activation of surviving cortico-spinal fibers thereby potentiating motor output. To test this hypothesis, we identified optimal thalamic targets and stimulation parameters that enhanced upper-limb motor evoked potentials and grip forces in anesthetized monkeys. This potentiation persisted after white matter lesions. We replicated these results in humans during intra-operative testing. We then designed a stimulation protocol that immediately improved voluntary grip force control in a patient with a chronic white matter lesion. Our results show that electrical stimulation targeting surviving neural pathways can improve motor control after white matter lesions.

Tetra-compartmental spinal infection with conus medullaris syndrome: illustrative case.

BACKGROUND: Recent literature suggests that spinal infections are increasing in prevalence. Any compartment can be infected in the spine; however, multicompartmental infections are rare. OBSERVATIONS: To the authors' knowledge, this report is the only reported case of a tetra-compartmental spinal infection consisting of epidural, subdural, subarachnoid, and intramedullary components with a contiguous lumbar spondylodiscitis resulting in conus medullaris syndrome requiring surgical intervention. LESSONS: This case highlights the importance of surgical intervention in severe cases such as the one illustrated in this report. Second, magnetic resonance imaging with and without contrast is required to check for spreading of the infection as these findings may change the surgical approach. Last, the use of intraoperative ultrasound is paramount to evaluate the subdural and intramedullary compartments in severe cases.