Purpose:Replicating spinal cord injury (SCI) in large animals is necessary for evaluating therapeutics for potential human translation, yet there is currently no commercial, standardized device for inducing SCI. We present the fabrication and testing of a custom impactor device for producing repeatable contusion SCI in porcine models. Methods:We first designed and built the device. Mechanical modeling was subsequently utilized to calibrate our benchtop testing setup. Benchtop verification was performed to measure impact force post calibration. We then used the device to generate a contusion SCI model in 2 pigs and the results were compared to an uninjured pig. Intraoperative ultrasound was used to visualize a hematoma in the injured spinal cord. Hematoxylin-eosin (H&E) and Masson's trichrome staining were used to confirm injury presence on ex vivo spinal cord samples. Results:Mechanical modeling forces matched benchtop impact forces within 1.4 N, indicating successful calibration of the testing setup. Our device demonstrated repeatability and the potential for modulating injury severity on the benchtop. Impactor forces were demonstrated across a range from 12.8 to 67.6 N, with variability remaining within 0.2 to 0.7 N standard deviation. The device induced two contusion injuries of different severity in vivo , confirmed by intraoperative ultrasound imaging and post-excision histology of the spinal cord. Conclusion:Our impactor device is a major advancement towards producing repeatable and titratable contusions in large animal SCI models.

Advancements in spine surgery have dramatically enhanced minimally invasive techniques, prominently through integrating robotic systems. Although pedicle screw placement remains the most widespread application of this technology, new developments are emerging to create innovative future avenues for these tools. This review explores the promising applications of robotic technology in minimally invasive spinal procedures, ranging from assistance with laminectomies and vertebroplasty to pain management and treatment of spinal tumors. We also discuss the potential for integrating artificial intelligence and augmented reality with robotic systems. If the current trajectory of research and innovation continues, there is promise in creating fully autonomous robotic systems that can revolutionize spine surgery by processing, planning, and performing procedures without heavy reliance on the surgeon.

OBJECTIVE There is a paucity of high-quality return-to-play (RTP) data following treatment of cervical spine injuries in contact sports. In this study, the authors gathered insights from National Football League (NFL) team spine surgeon consultants to highlight current practices in treating cervical spine injuries and report decision-making regarding RTP in professional American football players. METHODS A cross-sectional, online survey was distributed to all NFL consulting physicians specializing in the management of spine injuries. The survey covered the following five clinical vignettes of cervical spine injuries: 1) radiculopathy, 2) myelopathy, 3) unilateral facet fracture, 4) unilateral facet dislocation, and 5) neck pain with MRI showing a ligamentous STIR signal. Participants were asked about management options and criteria to clear players for RTP using a combination of multiple-choice and open-ended answers. RESULTS A total of 26 physicians from 21 of 32 (66%) teams responded. Anterior surgery was most commonly recommended for cervical disc herniation causing radiculopathy or myelopathy (73% and 88%, respectively). A rigid cervical orthosis was preferred by 68% of experts for initial management of nondisplaced unilateral facet fracture, but single-level anterior fusion was preferred by 56% for a unilateral facet dislocation. Common criteria to clear players for RTP with cervical disc herniation causing radiculopathy included a normal examination (85%), radiographic fusion postoperatively (58%), and pain-free range of motion (50%). Contraindications for RTP included persistent stenosis (35%), instability (31%), multilevel fusion (27%), and persistent cord signal change (23%). Additional criteria for RTP in players with facet fractures or dislocations included radiographic evidence of fracture healing (32% and 24%, respectively) and normal flexion/extension radiographs (24% and 32%, respectively). Finally, for players with isolated ligamentous STIR signal changes, resolution of MRI findings was required by 36% of responding physicians prior to RTP. CONCLUSIONS Decision-making regarding RTP after cervical spine injuries in professional football players is complex and influenced by improvement of symptoms, pain-free range of motion, and radiographic evidence of fusion or fracture healing. Respondents preferred anterior cervical discectomy and fusion for disc herniations causing cervical radiculopathy and myelopathy, rigid orthosis for unilateral facet fractures, and surgery for unilateral facet dislocations. The results of this study provide insight into how surgeons serving as consultants to professional football teams may counsel players who sustain cervical spine injuries.

While deep learning has catalyzed breakthroughs across numerous domains, its broader adoption in clinical settings is inhibited by the costly and time-intensive nature of data acquisition and annotation. To further facilitate medical machine learning, we present an ultrasound dataset of 10,223 Brightness-mode (B-mode) images consisting of sagittal slices of porcine spinal cords (N=25) before and after a contusion injury. We additionally benchmark the performance metrics of several state-of-the-art object detection algorithms to localize the site of injury and semantic segmentation models to label the anatomy for comparison and creation of task-specific architectures. Finally, we evaluate the zero-shot generalization capabilities of the segmentation models on human ultrasound spinal cord images to determine whether training on our porcine dataset is sufficient for accurately interpreting human data. Our results show that the YOLOv8 detection model outperforms all evaluated models for injury localization, achieving a mean Average Precision (mAP50-95) score of 0.606. Segmentation metrics indicate that the DeepLabv3 segmentation model achieves the highest accuracy on unseen porcine anatomy, with a Mean Dice score of 0.587, while SAMed achieves the highest Mean Dice score generalizing to human anatomy (0.445). To the best of our knowledge, this is the largest annotated dataset of spinal cord ultrasound images made publicly available to researchers and medical professionals, as well as the first public report of object detection and segmentation architectures to assess anatomical markers in the spinal cord for methodology development and clinical applications.

The field of spine surgery has long been characterized by innovations and technological advancements. The integration of artificial intelligence (AI) into spine surgery represents one of the latest technical developments in the field. The ability of AI to rapidly analyze datasets improves decision making, risk assessment, intraoperative precision, and postoperative management, all of which contribute to increasing personalized spine care and improving outcomes. However, the successful implementation of AI faces regulatory and privacy challenges that must be addressed before its full potential can be realized. Here, we provide a detailed analysis of the current applications and future prospects of AI in spine surgery, highlighting both the opportunities and challenges in this evolving field.

BACKGROUND: Using a multi-institutional oncology database, we investigate the survival rates and the impacts of demographic, clinical, and management characteristics on overall survival among adult patients diagnosed with spinal ependymoma. METHODS: Utilizing the SEER registry, patients with histologically or radiologically confirmed ependymomas were included. Factors impacting overall survival were analyzed using Kaplan-Meier survival curves and log-rank statistical analyses. RESULTS: A total of 1,580 patients were included. Their mean +/- standard deviation age was 46.68 +/- 15.96 years, and 51.1% were women. Gross total resection (GTR) was achieved in 66.4% of patients. The 5- and 10-year survival rates were 96.7% and 95.4%, respectively. A multivariable backward Cox regression showed that age >= 65 years was a significant predictor for mortality (hazard ratio [HR]: 3.93; 95% confidence interval [CI]: 2.21-7.00;- 7.00; P < 0.001). Likewise, tumor grade 3 (HR: 6.36; 95% CI: 1.95-20.76;- 20.76; P = 0.002), tumor grade 4 (HR: 7.74; 95% CI: 3.97-15.11;- 15.11; P < 0.001), presence of extra-neural metastasis (HR: 13.81; 95% CI: 3.67-51.96;- 51.96; P < 0.001), and receiving radiotherapy (HR: 2.50; 95% CI: 1.50-4.19;- 4.19; P < 0.001) were significant risk factors for mortality, while GTR was significantly associated with improved overall survival compared with subtotal resection or nonsurgical management (HR: 0.42; 95% CI: 0.25-0.73;- 0.73; P = 0.002). There were no significant effects for gender, race, marital status, income, residential area, chemotherapy, tumor size, and the presence of other benign or malignant tumors on the survival hazards (P > 0.05 for each). CONCLUSION: Early diagnosis and surgical management of spinal ependymomas, such as GTR, were associated with remarkable survival benefits. Old age, high-grade spinal ependymoma, and extra-neural metastasis were associated with worse overall survival, whereas radiotherapy's role remains unclear.

Applications and workflows around spinal robotics have evolved since these systems were first introduced in 2004. Initially approved for lumbar pedicle screw placement, the scope of robotics has expanded to instrumentation across different regions. Additionally, precise navigation can aid in tumor resection or spinal lesion ablation. Robot-assisted surgery can improve accuracy while decreasing radiation exposure, length of hospital stay, complication, and revision rates. Disadvantages include increased operative time, dependence on preoperative imaging among others. The future of robotic spine surgery includes automated surgery, telerobotic surgery, and the inclusion of machine learning or artificial intelligence in preoperative planning.

OBJECTIVE:Traditional management of patients with metastatic epidural spinal cord compression (MESCC) consists of radiotherapy (RT) with or without surgical decompression. With extensive literature and the introduction of clinical frameworks, such as the neurologic, oncologic, mechanical, and systemic criteria and the epidural spinal cord compression scale, progress has been made in refining the appropriate treatment regimen. In this review, we analyze the existing literature to identify the consensus frameworks and the remaining gaps in clinical knowledge. METHODS:PubMed, Embase, Cochrane, Web of Science, Scopus, and ClinicalTrials.gov were queried in January 2023. Only articles comparing combination therapy (surgery plus RT) to RT alone and assessing neurological and/or survival outcomes in patients with MESCC were retained for full-text review. RESULTS:Out of 2157 unique articles, 29 met inclusion criteria. The most common primary cancer locations included lung (n=1031, 20.0 %), breast (n=747, 14.5 %), and prostate (n=712, 13.8 %), and back pain was the most common symptom reported (n=1186/1622, 73.1 %). While baseline patient characteristics were not controlled between the different treatment regimens, the included studies demonstrated a median survival of 4.0 months (interquartile range [IQR] 3.0-6.1 months) in patients receiving RT alone compared to 7.7 months (IQR 6.3-11.1 months) in the cohort receiving combination therapy. Similarly, in patients undergoing RT alone, a median of 29.0 % (IQR 16.0-37.9 %) of patients experienced a neurologic improvement, compared to 38.0 % (IQR 31.5-64.4 %) of patients undergoing combination therapy. CONCLUSIONS:In patients with high-grade, symptomatic MESCC, combination therapy with direct circumferential decompression is superior to RT alone in patients with less radiosensitive tumors. In patients with high-grade asymptomatic MESCC, RT alone can be pursued for patients with the most radiosensitive tumors, such as myeloma and lymphoma; however, more research is needed on the treatment of less radiosensitive tumors. A major grey area exists in the treatment of patients with intermediate grade epidural involvement.

INTRODUCTION: Postoperative infection is a complication of spinal fusion surgery resulting in increased patient morbidity. Strategies including intraoperative application of powdered vancomycin have been proposed to reduce the incidence of infection, however such antimicrobial effects are short-lived. METHODS: Instrumentation of the L4-L5 vertebrae was performed mimicking pedicle screw and rod fixation in 30 rats. Titanium inoculated with PBS or 1x105 CFU bioluminescent MRSA and biomimetic bone grafts infused with varying concentrations of vancomycin were inserted before closure. Infection was quantified during the six-week postoperative period using IVIS bioluminescent imaging. Arthrodesis was evaluated using micro-CT. Histological analysis was utilized to evaluate fusion and leukocyte infiltration. RESULTS: Infected animals receiving a bone graft infused with high-dose vancomycin (0.89 mg/g) exhibited significantly lower bioluminescent signal over the six-week postoperative infection period (p = 0.032) than control animals inoculated with MRSA and implanted with bone grafts lacking vancomycin. Both high and low-dose (0.18 mg/g) vancomycin-infused grafts resulted in a statistically significant reduction in average bioluminescence when compared to control animals (p = 0.018 and p = 0.027, respectively), independent of time. MicroCT analysis of animals from each group revealed pseudoarthrosis only in the control group, suggesting a correlation between infection and pseudoarthrosis. Histology revealed the formation of fusion masses in all animals receiving vancomycin infused-bone grafts regardless of MRSA inoculation, with clearance of infection indicated by lack of abscess formation. MRSA-inoculated control animals receiving no vancomycin within the bone graft demonstrated significant abscess formation and lack of fusion mass. CONCLUSIONS: The novel vancomycin-infused, biomimetic bone graft effectively mitigated implant-associated infection while promoting fusion in a rat model of instrumented lumbar fusion.

OBJECTIVE:The differential diagnosis for postoperative back pain is broad, and conventional imaging modalities are not always conclusive. Therefore, we performed a systematic review of the literature and present case studies describing the use of single-photon emission CT (SPECT)/CT or positron emission tomography (PET)/CT in the diagnosis of back pain following spine surgery. METHODS:A systematic review was conducted according to PRISMA guidelines across 5 databases. Relevant keywords included PET/CT, bone SPECT/CT, and pseudarthrosis. The studies were assessed for diagnostic accuracy of the imaging technologies. RESULTS:A total of 2,444 studies were screened, 91 were selected for full-text review, and 21 were ultimately included. Six retrospective studies investigated the use of SPECT/CT with a total sample size of 309 patients. Two of these studies used SPECT/CT to predict screw loosening in over 50% of patients. Eight studies examined the use of 18-fluoride sodium fluoride (18F-NaF) PET/CT. Among these studies, measures of diagnostic accuracy varied but overall demonstrated the ability of 18F-NaF PET/CT to detect screw loosening and pseudarthrosis. Seven studies examined 18F-fluorodeoxyglucose (FDG) PET/CT and supported its utility in the diagnosis of postoperative infections in the spine. CONCLUSIONS:PET/CT and SPECT/CT are useful in the evaluation of postoperative pain of the spine, especially in patients for whom conventional imaging modalities yield inconclusive results. More diagnostic accuracy studies with strong reference standards are needed to compare hybrid imaging to conventional imaging.

OBJECTIVE:In posterior vertebral column subtraction osteotomy (PVCSO), a section of a thoracic or lumbar vertebra and the adjacent disc are resected to shorten the spinal column, aiming to permanently alleviate tension on the spinal cord in patients with recurrent tethered cord syndrome (TCS). The effects of this procedure on the spinal cord are not well characterized. This study investigated morphometric changes in the cord following PVCSO and assessed associated clinical outcomes in patients with recurrent TCS. METHODS:A retrospective review of patients with recurrent TCS undergoing PVCSO with robotic assistance at the authors' tertiary care institution between 2019 and 2023 was performed. Clinical data were recorded from electronic medical records, and morphometric measurements, including T12-L2 sagittal height, intradural diameter, and the diameters, area, eccentricity, and positioning of the spinal cord, were collected from MRI. Spinal cord dimensions including anteroposterior and lateral diameters, area, eccentricity, positioning, and intradural diameter were compared before and after surgery. RESULTS:Six patients were included in this study. At 6-week follow-up, all patients had improvement on lower-extremity motor function examinations, 40% had improvement on lower-extremity sensory function examinations, and 83% had improved self-reported pain. Bladder and bowel incontinence were improved in 50% and 60%, respectively. PVCSO reduced the height of the spinal column by a mean of 18.1 ± 5.2 mm. PVCSO increased the mean spinal cord anteroposterior diameter by 0.8 ± 0.5 mm at T12 (p = 0.03) and the mean area by 0.4 ± 0.3 mm2 at T12 (p = 0.03). The mean eccentricity of the spinal cord decreased by 0.15 ± 0.15 at L1 (p = 0.05), indicating that the spinal cord became more circular after surgery. No major complications were reported, although 1 patient experienced atelectasis and pulmonary embolism postoperatively. CONCLUSIONS:This study provides novel insights into the morphometric changes induced by PVCSO and their correlation with clinical outcomes in patients with TCS. The procedure effectively increased spinal cord dimensions, alleviating tension and offering potential benefits in symptom relief. The study underscores the need for objective metrics to guide surgical decision-making and enhance the long-term success of PVCSO in the management of TCS.

INTRODUCTION: Stem cells promote spinal cord injury (SCI) recovery by secreting paracrine factors that orchestrate endogenous healing mechanisms. However, effects in clinical trials are modest and there are no approved stem cell therapies to treat SCI. Major barriers include cell washout, immune attack, and oncogenic potential. METHODS: ITBs were implanted in three pigs. One pig received a cell-loaded ITB without injury (Cells), another received a cell-loaded ITB with injury (Cells + SCI), and another received a sham ITB with injury (SCI). SCIs were induced by weight drop at T5. ITBs were implanted cranial to the injury and sutured under the dura then loaded with human mesenchymal stem cells or sham cell media. Cerebrospinal fluid (CSF) was collected for 6 days following surgery through a lumbar drain. Cytokines in the CSF were measured by ELISA and the ITB was retrieved for cell viability staining. RESULTS: Upon retrieval, stem cells were alive on viability staining of the ITB. CSF levels of the pro-inflammatory cytokines IFNy and IL-1a were increased in the SCI condition compared to the Cells and Cells + SCI conditions. Pro-inflammatory cytokines peaked on post-operative day 5 and remained high. Anti-inflammatory cytokines IL-1ra, VEGF, and TGFβ were elevated in the SCI + Cells condition and depressed in the SCI condition compared to the Cells condition. Anti-inflammatory cytokines peaked on post-operative day 3 and decreased by day 6. CONCLUSIONS: In this pilot study, stem cells survived in an implantable ITB and altered cytokine levels in the CSF of pigs with SCI. Cell-loaded ITBs reduced pro-inflammatory cytokines and increased anti-inflammatory cytokines. Implantable ITBs warrant further study as they may represent a potential new delivery option for stem cell therapy.

ObjectiveSpinal 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.MethodsPatients 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.ResultsTwenty patients were identified, including 7 females (35%), with an overall median age of 66 years (range: 39-80 years) and median BMI of 25kg/m2 (range: 17-34kg/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.ConclusionsDespite 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.

BACKGROUND CONTEXT Spinal schwannomas are the most frequent primary benign tumors of the spine that can be associated with neurological deficits. The gold treatment is complete surgical resection. PURPOSE We aim to investigate the differences in the surgical variables and clinical outcomes by the tumor location. STUDY DESIGN/SETTING A retrospective review of the charts of patients who underwent surgical resection for nonsyndromic spinal schwannomas at Johns Hopkins Medical Institutes from 2009 to 2023. PATIENT SAMPLE A total of 123 patients were included in this study. OUTCOME MEASURES The functional outcomes, including pain, sensory deficits, and motor weakness at the last follow-up visit after the surgery, were studied. METHODS The patients were categorized into two groups by tumor location: those with schwannomas at the Functional Nerve Roots of C5-T1 or L2-S1 (FNRT group), while the other group includes the patients with schwannomas at other spinal levels (Non-FNRT group). RESULTS A total of 123 patients were included [mean (SD) age, 51.87 (16.96); 50.4% women]. The FNRT group includes 60 (48.8%) patients. The presenting symptoms were pain (89.4%), sensory deficits (47.2%), and weakness (37.3%), with no significant differences between FNRT and non-FNRT groups. Most patients (85.4%) underwent gross total resection (GTR), with a lower GTR rate in the FNRT group (76.7%) compared to non-FNRT cases (93.4%) (p=0.016). The average blood loss during operation, surgery duration, and hospital stay length were higher in the FNRT group than in the non-FNRT group (p<0.001). Postoperatively, the mean follow-up was 39.74 (171.65) months, with a longer duration among FNRT cases than non-FNRT (52.63 (244.40) vs 27.69 (36.90), p=0.013). Pain relief was reported in 78 patients, with a higher rate in the FNRT group (65.7%) than non-FNRT (59.0%) (p<0.001). The recovery rates from motor and sensory deficits were 67.1% and 44.1%, respectively, with higher rates among the non-FNRT patients than FNRT patients. Tumor recurrence occurred in 16 (13.0%) patients, with no significant difference between the study groups. CONCLUSIONS Spinal schwannomas are surgically curable with favorable outcomes and acceptable risks. The tumor location is essential in terms of resection extent, estimated blood loss, surgery duration, hospital stay length, and clinical outcomes. FDA Device/Drug Status This abstract does not discuss or include any applicable devices or drugs.

BACKGROUND:Robotic platforms have increased in sophistication for pedicle screw placement. Here, we review our institutional experience using ExcelsiusGPS to assess the accuracy rate of pedicle screw placement throughout the spine and characterize predictors of placement inaccuracy. STUDY DESIGN:Retrospective cohort study. METHODS:Patients from 2017 to 2022 undergoing spinal fusion surgery with ExelsiusGPS-assisted screw implantation at a single tertiary center were retrospectively identified. Patient demographics, preoperative symptoms, and operative details were collected. Postoperative computed tomography was used to classify screw placement accuracy according to the Gertzbein and Robbins scale (GRS). A stepwise multivariable ordered logistic regression analysis determined independent risk factors for clinically inaccurate screws (GRS C/D/E). RESULTS:One hundred and seventeen patients were included. Mean age was 60.6 ± 13.2 years, with 57% men, 72% white, and mean body mass index of 29.9 ± 6.4 kg/m2. Seven hundred and twenty-eight screws were placed, predominantly in the thoracic (29.5%) and lumbar (52.6%) regions. Accuracy classification indicated 670 GRS A, 31 GRS B, 22 GRS C, 4 GRS D, and 1 GRS E screws. The clinically acceptable screw placement rate (GRS A/B) was 96%. Male gender (odds ratio [OR]: 2.12, P = 0.03), revision surgery (OR: 2.43, P = 0.02), and thoracic level screw insertion (OR: 2.33, P = 0.01) were independently associated with inaccurate screw placement and explained 8.7% of the variability seen. Of the 728 screws placed, 3 required revision after postoperative imaging revealed loosening or pedicle breach. CONCLUSION:ExcelsiusGPS-assisted screw insertion has high placement accuracy and low revision rates. Identification of predictors of inaccuracy illustrates that similar variables, such as placement in the thoracic spine and revision surgery status, apply to both freehand and robotic screw placement. CLINICAL RELEVANCE:Robotic spine surgery is an accurate, reliable tool that can improve patient outcomes. Factors like male gender, thoracic screw placement, and revision surgery status are associated with lower screw placement accuracy, and these factors should inform surgical decision-making when using robotic assistance. LEVEL OF EVIDENCE: 4:

Background Tension in the spinal cord is a trademark of tethered cord syndrome. Unfortunately, existing tests cannot quantify tension across the bulk of the cord, making the diagnostic evaluation of stretch ambiguous. A potential non-destructive metric for spinal cord tension is ultrasound-derived shear wave velocity (SWV). The velocity is sensitive to tissue elasticity and boundary conditions including strain. We use the term Ultrasound Tensography to describe the acoustic evaluation of tension with SWV. Methods Our solution Tethered cord Assessment with Ultrasound Tensography (TAUT) was utilized in three sub-studies: finite element simulations, a cadaveric benchtop validation, and a neurosurgical case series. The simulation computed SWV for given tensile forces. The cadaveric model with induced tension validated the SWV-tension relationship. Lastly, SWV was measured intraoperatively in patients diagnosed with tethered cords who underwent treatment (spinal column shortening). The surgery alleviates tension by decreasing the vertebral column length. Results Here we observe a strong linear relationship between tension and squared SWV across the preclinical sub-studies. Higher tension induces faster shear waves in the simulation ( R 2 = 0.984) and cadaveric ( R 2 = 0.951) models. The SWV decreases in all neurosurgical procedures ( p < 0.001). Moreover, TAUT has a c-statistic of 0.962 (0.92-1.00), detecting all tethered cords. Conclusions This study presents a physical, clinical metric of spinal cord tension. Strong agreement among computational, cadaveric, and clinical studies demonstrates the utility of ultrasound-induced SWV for quantitative intraoperative feedback. This technology is positioned to enhance tethered cord diagnosis, treatment, and postoperative monitoring as it differentiates stretched from healthy cords.

BACKGROUND: Exoscopes were recently developed as an alternative to the operative microscope (OM) and endoscope for intraoperative visualization during neurosurgery. Prior reviews studying mixed cranial and spinal surgical cohorts reported advantages with exoscope use, including improved ergonomics and teaching. In recent years, there has been an increase in exoscope research, with no updated systematic review focused exclusively on the benefits and limitations of exoscope use in spine surgery. Thus, we sought to systematically synthesize the literature related to exoscope-assisted spine surgery. METHODS: A literature search was conducted using the PubMed, Embase, Scopus, Cochrane, and Web of Science databases to identify relevant studies reported between 2010 and September 2023. Data, such as the exoscope model used, procedure types performed, and user observations, were then collected. RESULTS: A total of 31 studies met our inclusion criteria, including 481 patients with spine pathologies who underwent a surgical procedure using 1 of 9 exoscope models. The lumbar region was the most frequently operated area ( n = 234; 48.6%), and discectomies comprised the most overall procedures ( n = 273; 56.8%). All patients benefited clinically. The reported advantages of exoscopes compared with OMs or endoscopes were improved focal distance, surgeon posture, trainee education, compactness, and assistant participation. Other aspects such as stereopsis, illumination, and cost had various observations. CONCLUSIONS: Exoscopes have advantages compared with OMs or endoscopes during spine surgery. The user learning curve is minimal, and no negative patient outcomes have been reported. However, some aspects of exoscope use necessitate longer term prospective research before exoscopes can be considered a standard tool in the armamentarium of intraoperative visualization strategies.

OBJECTIVE:Chronic low-back pain (LBP) is a leading cause of disability worldwide, and traditional pharmacotherapy fails to provide relief for many individuals with this condition. An estimated 15% of chronic LBP cases can be attributed to the facet joint. High-intensity focused ultrasound (HIFU) is a recent technology that enables noninvasive thermal ablation of tissue and has shown efficacy in treating tumors, neuropathic pain, and painful bone metastases. In this systematic review, the authors summarize the literature on lumbar facet joint-mediated pain treated with HIFU and report the effectiveness of HIFU on pain outcomes. METHODS:All full-text English-language articles describing the use of focused ultrasound for facet joint pain were screened using the PubMed/MEDLINE, Embase, Cochrane Library, Scopus, and Web of Science databases. Clinical studies were assessed for bias using the methodological index for nonrandomized studies. RESULTS:Eleven studies (6 preclinical and 5 clinical) reporting on 50 patients were included. Eight of these studies (73%) used MR-guided focused ultrasound ablation and 3 used fluoroscopy. The medial branch nerve and posterior facet joint capsule were the most common targets for focused ablation. Although the energy used ranged from 300 to 2000 J, clinical studies predominantly operated in the range of 1000 to 1500 J. Pain reduction was seen in all clinical studies, with multiple-point reductions from average baseline pain scores in 6-12 months. No study reported any adverse events or complications. CONCLUSIONS:HIFU can be effective in treating chronic low-back pain arising from the facet joint. Further clinical studies should explore the long-term effects of HIFU and monitor changes in pain reduction over time.

OBJECTIVE Pedicle screw placement guidance is critical in spinal fusions, and spinal surgery robots aim to improve accuracy and reduce complications. Current literature has yet to compare the relative merits of available robotic systems. In this review, the authors aimed to 1) assess the current state of spinal robotics literature; 2) conduct a meta-analysis of robotic performance based on accuracy, speed, and safety; and 3) offer recommendations for robotic system selection. METHODS Following PRISMA guidelines, the authors conducted a systematic literature review across PubMed, Embase, Cochrane Library, Web of Science, and Scopus as of April 28, 2022, for studies on approved robots for placing lumbar pedicle screws. Three reviewers screened and extracted data relating to the study characteristics, accuracy rate, intraoperative revisions, and reoperations. Secondary performance metrics included operative time, blood loss, and radiation exposure. The authors statistically compared the performance of the robots using a random-effects model to account for variation within and between the studies. Each robot was also compared with performance benchmarks of traditional techniques including freehand, fluoroscopic, and CT-navigated insertion. Finally, we performed a Duval and Tweedie trim-and-fill test to assess for the presence of publication bias. RESULTS The authors identified 46 studies, describing 4670 patients and 25,054 screws, that evaluated 4 different robotic systems: Mazor X, ROSA, ExcelsiusGPS, and Cirq. The weighted accuracy rates of Gertzbein-Robbins classification grade A or B screws were as follows: ExcelsiusGPS, 98.0%; ROSA, 98.0%; Mazor, 98.2%; and Cirq, 94.2%. No robot was significantly more accurate than the others. However, the accuracy of the ExcelsiusGPS was significantly higher than that of traditional methods, and the accuracies of the Mazor and ROSA were significantly higher than that of fluoroscopy. The intraoperative revision rates were Cirq, 0.55%; ROSA, 0.91%; Mazor, 0.98%; and ExcelsiusGPS, 1.08%. The reoperation rates were Cirq, 0.28%; ExcelsiusGPS, 0.32%; and Mazor, 0.76% (no reoperations were reported for ROSA). Operative times were similar for all robots. Both the ExcelsiusGPS and Mazor were associated with significantly less blood loss than the ROSA. The Cirq had the lowest radiation exposure. Robots tended to be more accurate and generally their use was associated with fewer reoperations and less blood loss than freehand, fluoroscopic, or CT-navigated techniques. CONCLUSIONS Robotic platforms perform comparably based on key metrics, with high accuracy rates and low intraoperative revision and reoperation rates. The spinal robotics publication rate will continue to accelerate, and choosing a robot will depend on the context of the practice.

BACKGROUND A 78-year-old male presented with progressive myelopathic symptoms. The clinical course and imaging findings raised a high suspicion for venous hypertensive myelopathy due to a spinal dural arteriovenous fistula (SDAVF). OBSERVATIONS Magnetic resonance angiography and four complete spinal angiograms did not reveal the presence of an SDAVF. Despite multiple negative angiograms, intraoperative ultrasound revealed abnormal cord edema and arterialized pulsatile vessels, confirming the presence of an SDAVF. The fistula was found and cauterized, which resulted in a decrease in the caliber of the dilated veins and an observed reduction of spinal cord stiffness posttreatment. The patient exhibited gradual improvement in neurological function. Retrospective analysis of the multiple complete spinal angiograms failed to reveal an anomaly at the treated level or any other level. LESSONS This case underscores the diagnostic utility of intraoperative Doppler ultrasound and the importance of maintaining a high index of suspicion for SDAVF in cases with consistent clinical characteristics and a lack of alternative diagnoses, even with negative spinal angiography. https://thejns.org/doi/10.3171/CASE24438