Spinal Cord Monitoring Research Articles

The Role of Spinal Cord Compression in Predicting Intraoperative Neurophysiological Monitoring Events in Patients With Kyphotic Deformity: A Magnetic Resonance Imaging-Based Study.

To establish a novel classification system for predicting the risk of intraoperative neurophysiological monitoring (IONM) events in surgically-treated patients with kyphotic deformity. Patients with kyphotic deformity who underwent surgical correction of cervicothoracic, thoracic, or thoracolumbar kyphosis in our center from July 2005 to December 2020 were recruited. We proposed a classification system to describe the morphology of the spinal cord on T2-weighted sagittal magnetic resonance imaging: type A, circular/symmetric cord with visible cerebrospinal fluid (CSF) between the cord and vertebral body; type B, circular/oval/symmetric cord with no visible CSF between the cord and vertebral body; type C, spinal cord that is fattened/deformed by the vertebral body, with no visible CSF between the cord and vertebral body. Furthermore, based on type C, the spinal cord compression ratio (CR) < 50% was defined as the subtype C-, while the spinal cord CR ≥ 50% was defined as the subtype C+. IONM event was documented, and a comparative analysis was made to evaluate the prevalence of IONM events among patients with diverse spinal cord types. A total of 294 patients were reviewed, including 73 in type A; 153 in type B; 53 in subtype C- and 15 in subtype C+. Lower extremity transcranial motor-evoked potentials and/or somatosensory evoked potentials were lost intraoperatively in 41 cases (13.9%), among which 4 patients with type C showed no return of spinal cord monitoring data. The 14 subtype C+ patients (93.3%) had IONM events. Univariate logistic regression analysis showed that patients with a type C spinal cord (subtype C-: odds ratio [OR], 10.390; 95% confidence interval [CI], 2.215-48.735; p = 0.003; subtype C+, OR, 497.000; 95% CI, 42.126- 5,863.611; p < 0.001) are at significantly higher risk of a positive IONM event during deformity correction compared to those with a type A. In further multiple logistic regression analysis, the spinal cord classification (OR, 5.371; 95% CI, 2.966-9.727; p < 0.001) was confirmed as an independent risk factor for IONM events. We presented a new spinal cord classification system based on the relative position of the spinal cord and vertebrae to predict the risk of IONM events in patients with kyphotic deformity. In patients with type C spinal cord, especially those in C+ cases, it is essential to be aware of potential IONM events, and adopt standard operating procedures to facilitate neurological recovery.

Evaluation of Conditions for the Development of Cryogenic Spinal Cord Injury Using a Canine Model: An Experimental Study on the Safety of Cryoablation for Metastatic Spinal Tumors.

Although the application of cryoablation to metastatic spinal tumors has been attempted, spinal cryoablation has the unique complication of cryogenic spinal cord injury. This study aimed to elucidate the conditions for the development of cryogenic spinal cord injury. Fifteen canines were used in this study. A metal probe was inserted into the 13th thoracic vertebral body. Cryoablation was performed for 10 minutes by freezing the probe in liquid nitrogen. The control canine underwent probe insertion only. Spinal cord monitoring, epidural temperature measurement, motor function assessment, and pathologic examination of the spinal cord were performed. During the 10 minutes of cryoablation, the epidural temperature decreased and reached the lowest epidural temperature (LET) at the end of cryoablation. The LETs (degrees celsius [°C]) of each canine were -37, -30, -27, -8, -3, -2, 0, 1, 4, 8, 16, 18, 20, and 25, respectively. As the epidural temperature decreased, waveform amplitudes also decreased. At the end of cryoablation (10 minutes after the start of cryoablation), abnormal waves were observed in 92.9% (13/14) of canines. With epidural rewarming, the amplitude of the waveforms tended to recover. After epidural rewarming (2 hours after the start of cryoablation), abnormal waves were observed in 28.6% (4/14) of canines. The LETs (°C) of the canines with abnormal waves after epidural rewarming were -37, -30, -27, and -8. None of the canines with normal waves after epidural rewarming had any motor impairment. In contrast, all canines with remaining abnormal waves after epidural rewarming had motor impairment. In the pathologic assessment, cryogenic changes were found in canines with LETs (°C) of -37 -30, -27, -8, 0, and 1. This study showed that 10-minute spinal cryoablation with LETs (°C) of -37, -30, -27, -8, 0, and 1 caused cryogenic spinal cord injury. There was no evidence of cryogenic spinal cord injury in canines with LET of ≥4°C. The epidural temperature threshold for cryogenic spinal cord injury is between 1 and 4°C, suggesting that the epidural temperature should be maintained above at least 4°C to prevent cryogenic spinal cord injury.

Prospective Validation of the Spinal Cord Shape Classification System in the Prediction of Intraoperative Neuromonitoring Data Loss: Assessing the Risk of Spinal Cord Data Loss During Spinal Deformity Correction.

The Spinal Cord Shape Classification System (SCSCS) class has been associated with spinal cord monitoring data loss during spinal deformity surgery. The objective of the current study was to prospectively validate the SCSCS as a predictor of spinal cord monitoring data loss during spinal deformity surgery. A prospective cohort study of consecutive patients who were undergoing primary deformity surgery at a single institution from 2018 to 2023 and whose major curve was in the spinal cord region was undertaken. Spinal cord morphology at the apex of the major curve on preoperative axial T2-weighted magnetic resonance imaging was used to categorize patients into 3 spinal cord shape types based on the SCSCS. The primary outcome was intraoperative neuromonitoring (IONM) data loss related to spinal cord dysfunction. Demographics and surgical and radiographic variables were compared between patients with IONM data loss and those without loss. Predictors of IONM loss were determined using bivariate and multivariable logistic regression analyses. A total of 256 patients (168 adult, 88 pediatric) were included and were separated into 3 SCSCS types: 110 (43.0%) with Type I, 105 (41.0%) with Type II, and 41 (16.0%) with Type III. IONM loss was observed in 30 (11.7%) of the 256 patients, including 7 (6.4%) of 110 with SCSCS Type I, 7 (6.7%) of 105 with Type II, and 16 (39.0%) of 41 with Type III. IONM loss was associated with SCSCS Type III, the preoperative deformity angular ratio, performance of 3-column osteotomies, greater operative time, greater transfusion volume, and greater postoperative sagittal corrections. SCSCS type was the strongest independent predictor of IONM data loss. SCSCS Type III had the greatest odds of IONM loss (odds ratio [OR] = 6.68, 95% confidence interval [CI] = 2.45 to 18.23 compared with Types I and II combined). The overall predictive performance with respect to IONM loss (area under the receiver operating characteristic curve = 0.827) was considered excellent. This prospective cohort study of patients undergoing spinal deformity correction confirmed that patients with a Type-III spinal cord shape had greater odds of IONM loss. Inclusion of the SCSCS in preoperative risk stratification and intraoperative management of spinal deformity corrective surgery is recommended. Prognostic Level II . See Instructions for Authors for a complete description of levels of evidence.

Real-Time Spinal Cord Motion Tracking for MR-guided Spine SBRT (A Pilot Study)

The aim of this study was to assess the feasibility of real-time motion tracking of the spinal cord using 2D-cine MRI on the MR-Linac system. Spinal SBRT delivers high-precision doses to targets near the spinal cord but with the dosimetric cord tolerance sometimes defined using a spinal cord PRV and the treatment alignment visualizing a surrogate measure (spinal canal) with cone beam CT guidance. MR-guided spine SBRT enables clear visualization of the true spinal cord and real-time monitoring of the cord during treatment, which may allow for increased cord dose constraints and offer new treatment options for patients with epidural disease. A Motion Monitoring Research Package (MMRP) that has the similar tracking functionality as the future motion management system for a 1.5 T MR-Linac system was used to track real-time target motion on 2D orthogonal T2-weighted bFFE cine MRI using a reference 3D T2 MRI scan to locate tracking object initially. The spinal cord was contoured from the T2 MRI scan as the tracking object, and the cine images were obtained in sagittal and coronal planes at the center of the contoured spinal cord with a temporal resolution of 1.2 seconds. The motion tracking data was collected for 20 min and retrospectively analyzed using standard deviation of motion was collected from two volunteers immobilized with the Klarity SBRT system on the MR-Linac couch during MRI scans of their cervical, thoracic, and lumbar spines. In the thoracic spinal cord, the was 0.07mm (left-right excursion range: ±0.15mm), 0.15mm (anterior-posterior: ±0.26mm), and 0.27mm (superior-inferior: ±0.53mm). In the lumbar spinal cord, the standard deviation was 0.06mm (±0.12mm), 0.1mm (±0.14mm), and 0.1mm (±0.27mm). In the cervical spine, since the tracking accuracy in Sup/Inf direction was compromised by tilted spine orientation in the orthogonal 2D image, a single entire vertebra including the spinal cord was tracked with a standard deviation of 0.19mm (±0.31mm), 0.27mm (±0.62mm), and 0.25mm (±0.4mm). This study demonstrated the possibility of real-time tracking of the spinal cord using 2D-cine MRI on an MR-Linac system. Future work will aim to increase sample size and evaluate the reproducibility of the tracking results over time. The excursion of the thoracic/lumbar spinal cord was found to be less than 0.5mm, while the anterior/posterior or superior-inferior excursion of the cervical spine was greater than 1.0mm during the 20-minute scan.

Importance of Multimodal Spinal Cord Monitoring and Hemodynamic Augmentation during High Thoracic Ventral Dural Tear Repair Using the Posterior Approach

AbstractCerebrospinal fluid (CSF) leakage due to large ventral dural tears (VDT) often requires surgical intervention. Surgical closure of a high thoracic VDT is challenging and associated with high morbidity, especially if it is performed after multiple epidural blood patch (EBP)/fibrin glue injections. A 44-year-old woman was diagnosed with spontaneous intracranial hypotension due to VDT at T1-T2, causing CSF leakage. Multiple EBP and fibrin glue injections failed to treat her symptoms; hence, the patient underwent surgical closure using the posterior approach. The patient was anesthetized using standard anesthetic drugs and was maintained under total intravenous anesthesia to facilitate continuous motor-evoked potential (MEP) monitoring. The surgical course was complicated by bleeding, hypotension, and MEP loss. Continuous MEP monitoring, effective team communication, quick restoration of blood pressure(BP) and BP augmentation with fluid, blood, and vasopressor helped to restore the MEP back to baseline. Hence, the patient recovered without neurological morbidity. This case report highlights the importance of adequate vascular access, multimodal spinal cord monitoring, and BP augmentation during a high thoracic VDT repair.

The adjunct use of descending neurogenic-evoked potentials when transcranial motor-evoked potentials degrade into warning criteria in pediatric spinal deformity surgery: minimizing false-positive events.

This studies objective was to evaluate the utility of descending neurogenic-evoked potentials (DNEPs) in the setting of transcranial motor-evoked potentials (TCeMEPs) degradation into warning criteria during pediatric spinal deformity surgery. An institutional spinal cord monitoring database was queried to identify all primary and revision pediatric spinal deformity cases, < / = 21years of age performed from 1/2006 to 12/2021, in which TCeMEPs were the primary motor tract assessment modality which degraded into warning criteria, with subsequent initiation of adjunct DNEPs. Fourteen surgical cases (0.42%; 3351 total cases) in fourteen patients met inclusion criteria. Mean age was 13.2years (7.5-21.3). syndromic (n = 7), kyphosis (n = 3), congenital (n = 2), and idiopathic (n = 2). Three-column osteotomies (3CO)were done in eight patients. TCeMEPs degraded into warning criteria during screw placement (n = 7), 3CO performance/closure (n = 4), or deformity correction (n = 3). DNEPs were present in all cases of warning-criteria TCeMEPs and one case had degradation of DNEPs. Intraoperative Stagnara wake-up tests were performed in only 2/14 cases, with one transient new neurologic deficit (NND). In this specific scenario, DNEPs sensitivity was 50%, specificity 100%, positive predictive value 100%, and negative predictive value 92% to detect aNND. DNEPs were useful in assessing spinal cord function in the setting of TCeMEP data degradation in complex pediatric deformity surgeries. DNEPs demonstrated a higher specificity and positive predictive value in this clinical setting than TCeMEPs when assessing long-term neurologic function after surgery. Based on this small cohort, DNEPs appear to be a useful adjunct modality to TCeMEPs, in this challenging clinical scenario.

Near-Infrared Spectroscopy for Spinal Cord Monitoring-A Roadmap to Translational Research in Aortic Medicine.

Extensive aortic aneurysms represent a unique challenge necessitating interdisciplinary efforts for safe and effective treatment. Despite various adjunctive neuroprotective strategies, ischemic spinal cord injury remains a devastating complication. This article describes the implementation of collateral network near-infrared spectroscopy as the first noninvasive spinal cord monitoring modality in the setting of extensive open and endovascular aortic repair, from early conceptualization to clinical utilization. Potential capabilities and remaining uncertainties based on current evidence are outlined and discussed.

Transcranial electric motor evoked potential monitoring during scoliosis surgery in children with cerebral palsy and active seizure disorder: is it feasible and safe?

Use of spinal cord monitoring in children with cerebral palsy (CP) and neuromuscular scoliosis is challenging. The previous reports suggest low success rates in the setting of CP, and it is unclear if transcranial electric motor evoked potentials (TcMEP) monitoring is contraindicated in patients with an active seizure disorder. The purpose of this study was to determine (1) are patients with CP able to be appropriately monitored with TcMEP? and (2) does TcMEP cause an increase in seizure activity? This was an institutional review board-approved retrospective cohort study observing 304 patients from 2011 to 2020. Inclusion criteria included all patients with CP undergoing posterior spinal fusion during this time. Intraoperative data were examined for the ability to obtain monitoring and any intraoperative events. Patients were followed for 3months postoperatively to determine any increase in seizure activity that could have been attributed to the TcMEP monitoring. Of the 304 patients who were observed, 21% (20.8%) were unable to be monitored due to lacking baseline signals from the extremities. Seventy-seven percent (77.5%) were successfully monitored with TcMEP. For these patients, no increased seizure activity was documented either intra- or postoperatively. A high percentage of children (77.5%) with CP were able to be successfully monitored with TcMEP during posterior spinal fusion. Furthermore, the concerns about increased seizure activity after TcMEP were not supported by the data from this cohort. Technical details of successful neuromonitoring in these patients are important and included increased stimulation voltage requirements and latency times. III retrospective comparative study.

Changes in medical costs for adolescent idiopathic scoliosis over the past 15 years.

Use of instrumentation has become widespread in spinal surgery due to intraoperative spinal cord monitoring, navigation, and improvement and development of implant materials. However, recent advances in spine surgery may have also led to an increase in medical costs. The purpose of this study is to investigate the trends of operative resource utilization and the costs of surgery for adolescent idiopathic scoliosis (AIS) over 15 years. Surgery for AIS was performed for 118 patients from January 2004 to December 2019 at national University Hospital. Trends were examined through retrospective calculation of the costs for outpatient, inpatient, and surgical services, and changes over time and the characteristics of fees were examined. Differences between groups were analyzed by Mann-Whitney U test and Student t-test. During the 15-year period, the length of hospital stay decreased, but costs for scoliosis surgery increased by 1.6 times and the total cost increased by 1.3 times. The fee for intensive care per day per person increased by 1.5 times. There were slight increases in MRI and CT fees, but no changes in fees for radiography, rehabilitation, subsequent visits, and prescriptions. New charges for medical supervision, medical clerk support, medical safety measures, and prevention of infection were added at different times during the 15-year period. Itemized costs related to surgery have increased with technological advances. Although these results only show changes in costs for AIS surgery, the findings indicate the challenges faced by the healthcare economy and the need for spine surgeons to understand medical costs.

Stimulation parameters for motor evoked potentials during intraoperative spinal cord monitoring. A systematic review

ObjectiveThe aim of this systematic review was to find the optimal stimulation parameters for muscle recorded transcranial electrical stimulation motor evoked potential (mTc-MEP) and D-wave monitoring during spinal cord monitoring. MethodsA PRISMA systematic search in Medline and EMBASE and a QUADAS-2 quality evaluation was performed to identify studies that compared stimulation parameters consisting of stimulation location, number of pulses, pulse duration, interstimulus interval, double train (DTS) or recurrent train stimulation (RTS) and intertrain interval (ITI) for performing mTc-MEP and D-wave monitoring. Only studies that used total intravenous anaesthesia (TIVA) were included. ResultsTen studies that compared stimulation parameters for performing mTc-MEP monitoring (stimulation location n = 4, number of pulses n = 2, pulse duration n = 1, interstimulus interval n = 4, DTS n = 1, RTS n = 2, ITI n = 2) were included. No studies compared stimulation parameters (stimulation location and pulse duration) for performing D-wave monitoring. ConclusionsFew studies examined the optimal stimulation parameters for monitoring mTc-MEPs and no studies were included for D-wave monitoring. There is a need for prospective research to investigate the optimal stimulation parameters for mTc-MEP with the use of TIVA and D-wave monitoring. SignificanceFor mTc-MEP monitoring, a table is provided in which the recommended stimulation parameters are stated.

Use of NEedle Versus suRFACE Recording Electrodes for Detection of Intraoperative Motor Warnings: A Non-Inferiority Trial. The NERFACE Study Part II

In the NERFACE study part I, the characteristics of muscle transcranial electrical stimulation motor evoked potentials (mTc-MEPs) recorded from the tibialis anterior (TA) muscles with surface and subcutaneous needle electrodes were compared. The aim of this study (NERFACE part II) was to investigate whether the use of surface electrodes was non-inferior to the use of subcutaneous needle electrodes in detecting mTc-MEP warnings during spinal cord monitoring. mTc-MEPs were simultaneously recorded from TA muscles with surface and subcutaneous needle electrodes. Monitoring outcomes (no warning, reversible warning, irreversible warning, complete loss of mTc-MEP amplitude) and neurological outcomes (no, transient, or permanent new motor deficits) were collected. The non-inferiority margin was 5%. In total, 210 (86.8%) out of 242 consecutive patients were included. There was a perfect agreement between both recording electrode types for the detection of mTc-MEP warnings. For both electrode types, the proportion of patients with a warning was 0.12 (25/210) (difference, 0.0% (one-sided 95% CI, 0.014)), indicating non-inferiority of the surface electrode. Moreover, reversible warnings for both electrode types were never followed by permanent new motor deficits, whereas among the 10 patients with irreversible warnings or complete loss of amplitude, more than half developed transient or permanent new motor deficits. In conclusion, the use of surface electrodes was non-inferior to the use of subcutaneous needle electrodes for the detection of mTc-MEP warnings recorded over the TA muscles.

Comparing Motor-Evoked Potential Characteristics of NEedle versus suRFACE Recording Electrodes during Spinal Cord Monitoring-The NERFACE Study Part I.

Muscle-recorded transcranial electrical stimulation motor-evoked potentials (mTc-MEPs) are used to assess the spinal cord integrity. They are commonly recorded with subcutaneous needle or surface electrodes, but the different characteristics of mTc-MEP signals recorded with the two types of electrodes have not been formally compared yet. In this study, mTc-MEPs were simultaneously recorded from the tibialis anterior (TA) muscles using surface and subcutaneous needle electrodes in 242 consecutive patients. Elicitability, motor thresholds, amplitude, area under the curve (AUC), signal-to-noise ratio (SNR), and the variability between mTc-MEP amplitudes were compared. Whereas amplitude and AUC were significantly higher in subcutaneous needle recordings (p < 0.01), motor thresholds and elicitability were similar for surface and subcutaneous needle recordings. Moreover, the SNRs were >2 in more than 99.5% of the surface and subcutaneous needle recordings, and the variability between consecutive amplitudes was not significantly different between the two recording electrode types (p = 0.34). Surface electrodes appear to be a good alternative to needle electrodes for spinal cord monitoring. They are non-invasive, can record signals at similar threshold intensities, have adequately high SNRs, and record signals with equivalent variability. Whether surface electrodes are non-inferior to subcutaneous needle electrodes in detecting motor warnings is investigated in part II of the NERFACE study.

Current Trends in Intraoperative Spinal Cord Monitoring: A Survey Analysis among Japanese Expert Spine Surgeons.

Although intraoperative spinal neuromonitoring (IONM) is recommended for spine surgeries, there are no guidelines regarding its use in Japan, and its usage is mainly based on the surgeon's preferences. Therefore, this study aimed to provide an overview of the current trends in IONM usage in Japan. In this web-based survey, expert spine surgeons belonging to the Japanese Society for Spine Surgery and Related Research were asked to respond to a questionnaire regarding IONM management. The questionnaire covered various aspects of IONM usage, including the preferred modality, operation of IONM, details regarding muscle-evoked potential after electrical stimulation of the brain (Br(E)-MsEP), and need for consistent use of IONM in major spine surgeries. Responses were received from 134 of 186 expert spine surgeons (response rate, 72%). Of these, 124 respondents used IONM routinely. Medical staff rarely performed IONM without a medical doctor. Br(E)-MsEP was predominantly used for IONM. One-third of the respondents reported complications, such as bite injuries caused by Br(E)-MsEP. Interestingly, two-thirds of the respondents did not plan responses to alarm points. Intramedullary spinal cord tumor, scoliosis (idiopathic, congenital, or neuromuscular in pediatric), and thoracic ossification of the posterior longitudinal ligament were representative diseases that require IONM. IONM has become an essential tool in Japan, and Br(E)-MsEP is a predominant modality for IONM at present. Although we investigated spine surgeries for which consistent use of IONM is supported, a cost-benefit analysis may be required.

WE-228. Current status of intraoperative spinal cord monitoring and its optimization

WE-228. Current status of intraoperative spinal cord monitoring and its optimization

Anterior cervical plating combined with zero-profile anchored spacer for the treatment of cervical facet dislocation in elderly patients

ObjectiveThe purpose of this study was to evaluate the efficacy of anterior cervical plating combined with zero-profile (Z-P) anchored spacer for the treatment of cervical facet dislocation in elderly patients. MethodsThis is a retrospective study. Twelve elderly patients (from 57 to 77 years old, averaged 65 years) with unilateral or bilateral facet dislocation of sub-axial cervical spine from September 2015 to September 2019 surgically treated at the authors’ hospital were enrolled in this study. The patients with osteoporosis or osteopenia were all surgically treated by anterior-only procedure using cervical plating combined with zero-profile anchored spacer after closed manual reduction under general anesthesia and spinal cord monitoring. The operation times (OT), estimated blood loss (EBL), perioperative complications, were recorded. The clinical evaluation included visual analogue scales (VAS) and the American Spinal Injury Association (ASIA) scale. The radiographic evaluation included kyphotic angle (KA) and disc height (DH) and the fusion rate. ResultsAnterior discectomy, interbody fusion and fixation were performed in all patients after the disloctions were reduced by manual maneuver. The average OT was 66 minutes, with a range from 45 to 110 minutes. The EBL averaged 42 ml per surgical procedure, with a range from 20 to 60 ml. The VAS, ASIA, KA were improved significantly after surgery (P<0.05). The average follow-up time was 24.2 months, with a range from 12 to 38 months. There were no statistical differences between the immediately post-op KA and KA at the last follow-up (P>0.05). No disc space subsidence was observed statistically (P<0.05) Interbody fusion was obtained in all patients. Two patient experienced slight difficulty in swallowing, which were improved 6 weeks later. There were no hardware failure, no segmental instability, no wound infection or other complications. ConclusionsManual reduction with spinal cord monitoring under general anesthesia is a safe and efficient option and the anterior cervical plating combined with Z-P spacer could achieve reliable fixation for the patients with cervical facet dislocation in the elderly patients with osteoporosis or osteopenia.

Study of the latency of transcranial motor evoked potentials in spinal cord monitoring during surgery for adolescent idiopathic scoliosis

ObjectiveAn increase in the latency of a motor evoked potential might be as significant as a decrease in amplitude to predict a significant and clinically symptomatic neurological injury in spinal surgery for adolescent idiopathic scoliosis. The aim of the study was to investigate the impact of monitoring of latency of motor evoked potentials during spinal surgery for adolescent idiopathic scoliosis by describing intraoperative data. MethodsPreoperative recordings of 50 patients undergoing posterior spinal fusion for idiopathic scoliosis were studied. Latencies of appearance of the motor evoked potential curves on the right and left side were recorded for each group of muscles at several key moments during the procedure (basal, before the first implant, before and after corrective maneuvers). ResultsMean latencies were approximately the same in each muscle group on the right and the left side, before and after correction. There was no significant increase in latency during surgery. Overall results showed that the measured latency did not differ significantly between the two age groups (p=0.07). Negative correlation between height and the means of latencies was recorded in the abductor pollicis brevis and abductor digiti minimi (r=0.4; p=0.009), rectus femoris (r=0.4; p=0.01), tibialis anterior (r=0.4; p=0.007), and abductor hallucis (r=0.5; p=0.0004). No significant correlation was found between age and intraoperative parameters. ConclusionIntraoperative latency could be a reliable intraoperative monitoring criteria with low variability, that might be used to predict postoperative motor deficits in surgery for adolescent idiopathic scoliosis.

Thoracolumbar and Lumbar Posterior Vertebral Resection for the Treatment of Rigid Congenital Spinal Deformities in Pediatric Patients: A Long-Term Follow-up Study

ObjectiveWe sought to determine whether a posterior vertebral resection on congenital deformities of thoracolumbar and lumbar vertebrae leads to more complications and provides less correction.MethodsTwenty-three patients underwent a posterior vertebral resection for a rigid congenital spinal deformity, which included scoliosis (13 patients), kyphoscoliosis (6 patients), and pure kyphosis (4 patients). The surgeries involved removing 1 to 2 vertebrae using multiaxial pedicle screws in all but 2 of the patients. All surgeries were performed under intraoperative spinal cord monitoring. Thoracic curve, lumbar lordosis, focal kyphosis, shift, and sagittal vertical axis were collected at baseline and during the last follow-up (taking place after at least 3 years) and were then statistically analyzed.ResultsThe major curve correction was about 55% in cases of scoliosis, with focal kyphosis improving from 54.3 ± 19.1 degrees to 21.3 ± 15 degrees. Two patients experienced intraoperative neuromonitoring changes, with data returning to baseline without any surgical intervention. Sensory or motor palsy after the surgery was not reported in patients.Despite improving sagittal or coronal deformities, 8 patients experienced excessive sagittal decompensation during follow-up, 1 of whom underwent revision surgery. Sagittal decompensation was by far the most common complication. Larger kyphoscoliosis or focal kyphosis angles were preoperative risk factors for postoperative sagittal imbalance (P value < 0.05).ConclusionsUsing a lumbar or thoracolumbar posterior vertebral resection enables surgeons to correct rigid curves in the pediatric population without major risk to nerve roots. The primary complications would be sagittal decompensation and the likelihood of undercorrection, which requires mindful addressing during the preoperative planning stages.

Review of the Role of Intraoperative Neurophysiological Monitoring in Spinal Surgery With a Focus on the True and False Positives and a Clinical Correlation.

Spinal surgery is a technically challenging endeavor with potentially devastating complications. Intraoperative neurophysiological monitoring (IONM) is a method of preventing and identifying damage to the spinal cord. The aim of our study was to examine the clinical utility of IONM in spinal surgeries performed at our institution and what effect, if any, subsequent interventions had on postoperative patient outcomes. This is a retrospective cohort study of 169 patients who underwent spinal surgery with IONM at 2 institutions between 2013 and 2018. Signal changes detected were recorded as well as the surgeon's response to these changes. Neurological status was recorded using a standard neurological examination and characterized as per the McCormick Neurological Scale. Patients were followed up for 12 months after surgery. A total of 169 spinal surgery cases with concurrent use of spinal cord monitoring were carried out in our institution between 2013 and 2018. The youngest patient was 14 years old, and the oldest was 92 years old (mean, 51.9 ± 19.6 years). There were 100 female patients and 69 male patients. Most patients (n = 124) had no signal changes. Signal changes were observed in 26.6% of the cases (n = 45). Most of these signal changes were rectified through repositioning of the patient (n = 24). The other 21 patients saw no improvement in their signals before the end of their procedures; however, these 21 patients had no postoperative deficits (grade I). This brought the false positive rate to 38% (21/55); the false negative rate was 1.8% (3/169). This study showed similar outcomes in patients whether IONM signals were recovered or not. The false positive and false negative rates were high. Our study helps to raise awareness about IONM's strengths and weaknesses to inform future clinical practice. We recommend prioritizing clinical judgment in spinal surgery cases and using IONM with caution.

Gold nanodots with stable red fluorescence for rapid dual-mode imaging of spinal cord and injury monitoring.

Spinal cord injury is one of the most devastating complications of spinal surgery, often resulting in numbness, pain or paralysis. Minor injuries in the spinal cord are hard to be identified and existing imaging modalities are unable to provide intraoperative monitoring. Monitoring pathological change at the site of injury is a key factor in staging and treatment decision making as well as prognosis of spinal cord injury. Herein, we offer the fluorescence imaging with intraoperative visualization and detection accuracy for bioimaging to resolve the problem. A novel red fluophore AuNDs caped with glutathione is prepared, which exhibits some advantages such as ultra-small size, negligible biotoxicity, superior water solubility and great biocompatibility. AuNDs fluorophore especially exhibit both of a remarkable photoluminescence stability and high attenuation coefficient to X-rays. In addition, AuNDs can be used as CT contrast agent for spinal cord, which avoid the high toxicity and weak CT signal of traditional iodine contrast. After intradural injection into the spinal cord, AuNDs are transported through the flow of cerebrospinal fluid and bound to the spinal cord parenchyma. not only the bioimage of the entire spinal cord can be achieved as quick as 15min, but they are also particularly beneficial to long-term imaging of complex physiological environments in vivo, with negligible quenching. Comparing from the bright red fluorescence in adjacent normal spinal cord sites, there is almost no fluorescence in spinal cord at the areas of the injury. We suggest that AuNDs are unable to enter the injury sites of necrosis and ischemia, which promote a different contrast imaging from the normal one. The bright red fluorescence of the AuNDs significantly overcome the restriction of the blue autofluorescence of the biological tissues, providing a clear boundary for observation of the thin spinal cord injury. As a result, we developed the AuNDs with fluorescent and CT dual-mode bioimaging capability to clearly and effectively diagnose spinal cord injury, which are expected to provide a novel visualization imaging regent for clinical use.

Dosimetric comparison of robotic- and LINAC-based treatment of spine stereotactic body radiotherapy.

To determine which treatment technique and modality would offer better dosimetric results and be preferable for spinal stereotactic body therapy (SBRT) depending on the three different regions of the vertebrae. Linear accelerator (LINAC)- and CyberKnife (CK)-based treatment techniques were compared in terms of their dosimetric quality, treatment efficiency, and delivery accuracy. Thirty previously treated patients were included in this study. Intensity-modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) techniques were used for LINAC-based treatment, whereas CK-based treatment plans were generated for two different collimator systems: fixed and multileaf collimator (MLC). The plans were compared based on spinal cord sparing, dose homogeneity, conformity index (CI), gradient index (GI), monitor unit (MU), and beam-on time. The percentage volumes of V2Gy, V5Gy (representing volume low of the dose spillage region), V10Gy, and V20Gy (representing the volume of the high-dose spillage region) of the healthy tissue were analyzed. The CI and GI of the VMAT plans were better than those of the IMRT plans. For spinal cord sparing, the VMAT and MLC-based CK (CK-MLC) techniques were superior. The percentage of low-dose spillage regions was the lowest for IMRT and fixed cone-based CK (CK-FIX) plans. The percentage of the high-dose spillage region was the lowest for the VMAT and CK-MLC plans. In terms of treatment efficiency, the VMAT and CK-MLC plans were superior to the IMRT and CK-FIX plans. The VMAT technique lowered the MU and beam-on time values. The plan delivery accuracy of the VMAT and CK-FIX plans was better than that of the IMRT plans. VMAT is the best option for LINAC-based spinal SBRT. For CK-based spinal SBRT, MLC-based plans are preferred. If the clinic has both treatment modalities and the patient can tolerate long treatment times, CK-MLC-based treatment should be chosen because of its superiority in sparing the spinal cord and sharp dose fall-off.