Intradural Extramedullary Spinal Tumors Research Articles

Lumbar Spinal Meningioma- A common tumor in an uncommon location: A case report

Meningioma in the spinal canal commonly appears as intradural extramedullary spinal tumors at the dorsal and cervical region but is rare in the lumbar area. A 36-year-old man presented to us with complaints of left sciatica, weakness, and difficulty in movements of his left toes for a couple of months. Magnetic Resonance Imaging revealed an enhancing oval-shaped lesion at the level of L4, and histopathology revealed a meningioma. The complete removal has been done with hemilaminectomy for this common tumor in an uncommon location. J Shaheed Suhrawardy Med Coll 2023; 15(1): 78-82

Clinical evaluation of enhanced recovery versus conventional care in the perioperative period for intradural extramedullary spinal tumors: a study protocol for a multicenter, randomized controlled trial

BackgroundThis randomized clinical trial protocol aimed to investigate the comparative efficacy of an enhanced recovery after surgery (ERAS) protocol versus traditional perioperative care programs in patients with intradural extramedullary spinal tumors.MethodsThe study included 180 patients aged 18–80 years, who were randomly assigned to two groups: Group A receiving traditional perioperative care and Group B receiving accelerated rehabilitation perioperative care. The nurse responsible for patient care was informed of the group assignment, but the patients themselves remained blinded to the intervention. The primary outcome measure was the Karnofsky Performance Scale score, which assessed functional status. The secondary outcomes included the Japanese Orthopedic Association Scale, Numeric Pain Rating Scale, length of postoperative hospital stay, duration of urethral catheterization, patient satisfaction questionnaire, and complication rates. Follow-up assessments were conducted telephonically 1 month, 3 months, and 6 months after the surgery.DiscussionThis study protocol provided a structured approach to assess the potential benefits of ERAS during the perioperative period for patients with intradural extramedullary tumors, aiming to improve patient outcomes and overall care efficiency.Trial registrationThis study has been registered with the China Clinical Trials Registry (Project No: ChiCTR2200063347). Registered on September 5 2022.

Functional outcome after introduction of hemilaminectomy in management of spinal schwannomas and meningiomas

BackgroundSchwannomas and meningiomas are intradural extramedullary spinal tumors which are regularly encountered in the neurosurgical clinic. These tumors cause neurological deficit by compression on the spinal cord and commonly pain when affecting the cauda equina. The traditional treatment with standard laminectomy (SL) can cause instability to the dorsal segments of the spinal column, and the less invasive option of hemilaminectomy (HL) has therefore been developed. We aim in this study to investigate transition from SL to HL in a population-based cohort. MethodsAdult patients (18 years and older) undergoing primary surgery due to spinal meningioma or schwannoma between 2007 and 2022 at the neurosurgical clinic were included. Data related to clinical, surgical and outcome variables were retrospectively collected. ResultsA total of 187 patients were identified: 155 in the SL group, 26 in the HL group and in 6 patients a combination of SL and HL. The mean age of the SL group was 62.7 years (SD14.2) compared to 58.0 (SD15.7) in the HL group (p = 0.16). Preoperative motor deficit was more common in SL group compared to HL group (76.8 % and 61.5 %, respectively, p = 0.14). Thoracal location was most common for both groups (SL 65.8 % and HL 61.5 %). Postoperative change in McCormick grades and early complications were similar between groups. ConclusionOutcome after hemilaminectomy due to intradural extramedullary schwannoma or meningioma is comparable to standard laminectomy with regards to postoperative complications and neurological improvement. Our findings support the transition to hemilaminectomy in selected cases.

Does Minimally Invasive Hemilaminectomy for Intradural Extramedullary Tumor Resection Prevent Postlaminectomy Kyphosis or Lordosis Loss?

Minimally invasive hemilaminectomy is a safe and effective alternative to open laminectomy for treating intradural extramedullary tumors. There are no reports of postoperative kyphosis after this approach. This study aims to determine whether performing minimally invasive spine surgery hemilaminectomy for intradural extramedullary tumors can prevent the development of postlaminectomy kyphosis (PLK) or lordosis loss. Sixty-five patients with spinal intradural extramedullary tumors who underwent minimally invasive hemilaminectomy surgery and complete pre and postoperative radiologic imaging were included. The effect of the surgical approach on the spinal sagittal axis was assessed by comparing pre- versus postoperative segmental and local Cobb angles at different spinal levels, considering anatomical localization (cervical, thoracic, lumbar, and transition segments) and functional features (mobile, semi-rigid, and transition segments), as well as the extent of the surgical approach (1, 2, or 3 levels) and follow-up. None of the patients had an increase in thoracic kyphosis nor a loss of cervical or lumbar lordosis greater than or equal to 10° after undergoing the minimally invasive spine surgery hemilaminectomy approach.More than 5° of increase in kyphosis was detected on 7.4% and 11.1%, for the segmental and the local angles, respectively; meanwhile, for patients with loss of lordosis, this deviation was detected in 5.3%, for both angles. The occurrence of PLK was more common than that of lordosis loss, but mainly manifested in postoperative angle impairment of less than 5°. No significant differences were evidenced, considering theapproach length. Hemilaminectomy represents a promising approach for preventing PLK and postlaminectomy lordosis loss following intradural extramedullary tumor resection.

SPINAL INTRADURAL EXTRAMEDULLARY TUMORS AND SIMILAR PATHOLOGIES: A SINGLE CENTER STUDY

Background: We wanted to analyze the neurological symptoms and prognosis of five spinal IDEM (intradural extramedullary) tumors cases diagnosed, and to emphasize that a spinal cord tumor can be found incidentally in evoluation of the proximal regions of the vertebral column in patients who were mistakenly operated for lumbar disc herniation on lumbar MRI, but whosesymptoms did not resolve. Objective: To emphasize the need for examinations such as MRI along the vertebral columna in patients with different spinal pathologies and whose symptoms and clinical signs do not improve. Methods: Patients with spinal IDEM tumors treated with surgical excision and followed for more than 2 years were retrospectively analyzed. Issessed pain with the visual analo scale (VAS), and neurological function with the Nurrick grade.Preoperative complaint time,location of tumor in sagital and axial sections in MRI and pathological diagnosis were investigated. Results: The pathological diagnosis in our study was meningioma in two cases,dural arteriovenous fistula in one case,teratoma in one case ,and myxopapilary epandimoma in one case.İn one case,disc herniation surgery was performed in another hospital due to misdiagnosis, but because the patient’s complaints were resistant. In examination, an IDEM tumor at T11 level was detected, and he was operated. In all cases the VAS score (mean) was reduced from 7.8 to 0.4 as well as the Nurrick grade (mean) was from 2.0 to 0.6. In the dAVF case, spasticity in the lower extremities, bladder and bowel disfunction continued. Conclusion: In cases with severe neurological deficits, MRI scanning of the proximal parts of the vertebral column will help in the differential diagnosis of the lesion occupying the intraspinal space.

Diagnostic Accuracy of Somatosensory Evoked Potential and Transcranial Motor Evoked Potential in Detection of Neurological Injury in Intradural Extramedullary Spinal Cord Tumor Surgeries: A Short-Term Follow-Up Prospective Interventional Study Experience from Tertiary Care Center of India.

Objective Intraoperative neuromonitoring (IONM) is an acknowledged tool for real-time neuraxis assessment during surgery. Somatosensory evoked potential (SSEP) and transcranial motor evoked potential (MEP) are commonest deployed modalities of IONM. Role of SSEP and MEP in intradural extramedullary spinal cord tumor (IDEMSCT) surgery is not well established. The aim of this study was to evaluate sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of SSEP and transcranial MEP, in detection of intraoperative neurological injury in IDEMSCT patients as well as their postoperative limb-specific neurological improvement assessment at fixed intervals till 30 days. Materials and Methods Symptomatic patients with IDEMSCTs were selected according to the inclusion criteria of study protocol. On modified McCormick (mMC) scale, their sensory-motor deficit was assessed both preoperatively and postoperatively. Surgery was done under SSEP and MEP (transcranial) monitoring using appropriate anesthetic agents. Gross total/subtotal resection of tumor was achieved as per IONM warning alarms. Sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of SSEP and MEP were calculated considering postoperative neurological changes as "reference standard." Patients were followed up at postoperative day (POD) 0, 1, 7, and 30 for convalescence. Statistical Analysis With appropriate tests of significance, statistical analysis was carried out. Receiver-operating characteristic curve was used to find cutoff point of mMC for SSEP being recordable in patients with higher neurological deficit along with calculation of sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of SSEP and MEP for prediction of intraoperative neurological injury. Results Study included 32 patients. Baseline mean mMC value was 2.59. Under neuromonitoring, gross total resection of IDEMSCT was achieved in 87.5% patients. SSEP was recordable in subset of patients with mMC value less than or equal to 2 with diagnostic accuracy of 100%. MEP was recordable in all patients and it had 96.88% diagnostic accuracy. Statistically significant neurological improvement was noted at POD-7 and POD-30 follow-up. Conclusion SSEP and MEP individually carry high diagnostic accuracy in detection of intraoperative neurological injuries in patients undergoing IDEMSCT surgery. MEP continues to monitor the neuraxis, even in those subsets of patients where SSEP fails to record.

Differentiation of the Intradural Extramedullary Spinal Tumors, Schwannomas, and Meningiomas Utilizing the Contrast Ratio as a Quantitative Magnetic Resonance Imaging Method

Schwannomas and meningiomas are the most common intradural extramedullary spinal tumors; however, differentiating between them using magnetic resonance imaging (MRI) is a frequent challenge. In this study, we aimed to investigate the use of the contrast ratio (CR) as a quantitative MRI method in the differentiation of schwannomas and meningiomas. We analyzed the data of patients with intradural extramedullary spinal tumors who underwent surgery and were diagnosed with either schwannomas or meningiomas by histopathological analysis. Regions of interest were set for the entire spinal tumor on T2-weighted sagittal MRI. To obtain the CR values of spinal tumors (CRtumor), we used the signal intensity (SI) values of the tumor (SItumor) and spinal cord (SIcord) according to the following formula: [CRtumor= (SItumor-SIcord)/(SItumor+SIcord)]. The study included 50 patients (23 males and 27 females) with a mean age of 61.5 years old (11-85 years old). Histopathological analysis revealed that 33 and 17 patients were diagnosed with schwannomas and meningiomas, respectively. The mean CR values of the schwannomas and meningiomas were 0.3040±0.1386 and 0.0173±0.1929, respectively. The CR value of the schwannomas was statistically significantly higher than that of meningiomas (P<0.01). The cutoff CR value obtained from the receiver operating characteristic curve was 0.143, with a specificity and sensitivity of 90.9% and 88.2%, respectively. Furthermore, the value for the area under the receiver operating characteristic curve was 0.925 (95% confidence interval: 0.852-0.998). The evaluation of CRs by using MRI to distinguish between schwannomas and meningiomas is a beneficial quantitative tool.

Spinal Meningiomas: A Comprehensive Review and Update on Advancements in Molecular Characterization, Diagnostics, Surgical Approach and Technology, and Alternative Therapies.

Spinal meningiomas are the most common intradural, extramedullary tumor in adults, yet the least common entity when accounting for all meningiomas spanning the neuraxis. While traditionally considered a benign recapitulation of their intracranial counterpart, a paucity of knowledge exists regarding the differences between meningiomas arising from these two anatomic compartments in terms of histopathologic subtypes, molecular tumor biology, surgical principles, long-term functional outcomes, and recurrence rates. To date, advancements at the bench have largely been made for intracranial meningiomas, including the discovery of novel gene targets, DNA methylation profiles, integrated diagnoses, and alternative systemic therapies, with few exceptions reserved for spinal pathology. Likewise, evolving clinical research offers significant updates to our understanding of guiding surgical principles, intraoperative technology, and perioperative patient management for intracranial meningiomas. Nonetheless, spinal meningiomas are predominantly relegated to studies considering non-specific intradural extramedullary spinal tumors of all histopathologic types. The aim of this review is to comprehensively report updates in both basic science and clinical research regarding intraspinal meningiomas and to provide illustrative case examples thereof, thereby lending a better understanding of this heterogenous class of central nervous system tumors.

Functional outcomes in intradural extramedullary spinal tumors.

Intradural extramedullary (IDEM) spinal cord tumors account for approximately two-thirds of benign intraspinal neoplasms. These are amenable to gross total excision but can have variable functional outcomes, which plays a key role in assessing their impact on a patient's quality of life. Understanding the functional outcomes associated with these tumors is crucial for healthcare professionals to devise appropriate treatment plans and provide comprehensive care. In this study, we retrospectively reviewed the outcomes of 130 patients with IDEM tumors who underwent surgery in the past six years between January 2017 and December 2022 at a single institution. Patient demographics, symptoms, and tumor characteristics (anatomical and pathological) in all operated spinal IDEM tumors were analyzed. The neurological findings obtained during the preoperative stage and the postoperative follow-up were evaluated according to the Frankel grading. The back pain was assessed using the Denis pain scale (DPS). The age range, gender distribution, presentation, histopathology, and tumor characteristics were analyzed. The histopathological outcomes of the study were as follows: 56 cases of schwannoma, 37 cases of meningiomas, 16 patients of neurofibroma, six cases of epidermoid cyst, five cases each of ependymoma and dermoid cyst, three cases of arachnoid cyst, two cases of metastasis, and one case of paraganglioma. Pain was the most common symptom (38.5%), followed by weakness in limbs (31.5%), paresthesia/numbness (22.3%), and sphincter disturbance (7.7%). Complete total resection was seen in 93% of cases, with 7% undergoing subtotal excision. The complications encountered were - four cases of surgical site infection and one case each of cerebrospinal fluid leak, pseudomeningocele, and epidural hematoma. In our series, 49.3% of patients had significantly good improvement in functional outcomes as per improvement in Frankel score, and 43% of patients had good functional improvement. Significant functional improvement was noted at immediate postoperative follow-up, 2-week follow-up, and six-month follow-up periods. Reoccurrence was seen in 7 cases (5.4%). The DPS score mean values showed a significant decrease over the follow-up duration as compared to preoperative mean values. Significantly poor outcome was seen in IDEM tumours present anteriorly. The IDEM tumors are usually benign and are readily detected by contrast-enhanced magnetic resonance imaging scans. These have variable functional outcomes in different centers. Assessing this functional outcome is an essential aspect of managing IDEM spinal tumors. It was observed through our study that the ventral location of the tumor, thoracic tumors, and poor preoperative neurological status of the patient correspond with poorer postoperative functional outcomes. Furthermore, a significant decrease in the pain symptoms with improvement of Frankel score was seen postoperatively, thus this being suggestive of a significant improvement of functional outcome after surgery. This study helps to conclude that the morbidity associated with the resection of IDEM tumors is not as significant as originally thought to be.

Digital 3D Exoscope is Safe and Effective in Surgery for Intradural Extramedullary Tumors: A Comparative Series

Digital 3D exoscopes have been shown to be comparably safe and effective as surgical microscopes in complex microneurosurgical procedures. However, the results of exoscopic spinal tumor surgeries are scarce. The purpose of this study is to compare results of a transition from microscope to exoscope in surgeries for spinal intradural extramedullary tumors. We included all consecutive patients with intradural extramedullary spinal tumors operated on by the senior author during January 2016 to October 2023. The 3D exoscope was used in the latter half of the series from November 2020. We evaluated pre- and postoperative clinical findings, imaging studies, intra- and postoperative events, and analyzed surgical videos from the operations retrospectively. We operated 35 patients (exoscope n= 19, microscope n= 16) for intradural extramedullary tumors (meningioma n= 18, schwannoma n= 12, other n= 5). Tumors in the cervical and thoracic spine were more common than in the lumbar region. The duration of surgery was slightly longer (median 220 vs. 185 minutes) in the exoscope group. However, the rate of gross total resection of the tumor was higher (81% vs. 67%) and the tumors more often located anteriorly to the spinal cord (42% vs. 13%) in the exoscope group. No major complications (i.e., permanent motor deficit or postoperative hematoma) occurred in either group. We saw postoperative gait improvement in 81% and 85% of the patients with preoperative deterioration of gait after exoscopic and microscopic surgeries, respectively. This study demonstrates that exoscope-assisted surgery for spinal intradural extramedullary tumors is comparable in safety and effectiveness to traditional microscopic surgery.

Differentiation between Anterior and Posterior Roots Using Compound Muscle Action Potential in Intradural Extramedullary Spinal Tumor Surgery.

This study aims to determine the cutoff values for the compound muscle action potential (CMAP) stimulus in anatomically identified anterior (motor nerve) and posterior roots (sensory nerve) during cervical intradural extramedullary tumor surgery. The connection between CMAP data from nerve roots and postoperative neurological symptoms in thoracolumbar tumors was compared with data from cervical lesions. The participants of the study included 22 patients with intradural extramedullary spinal tumors (116 nerve roots). The lowest stimulation intensity to the nerve root at which muscle contraction occurs was defined as the minimal activation intensity (MAI) in the CMAP. In cervical tumors, the MAI was measured after differentiating between the anterior and posterior roots based on the anatomical placement of the dentate ligament and nerve roots. The MAIs for 20 anterior roots in eight cervical tumors were between 0.1 and 0.3 mA, whereas those for 19 posterior roots were between 0.4 and 2.0 mA. The cutoff was <0.4 mA for both the anterior and posterior roots, and sensitivity and specificity were both 100%. In thoracolumbar tumors, the nerve root was severed in 12 of 14 cases. All MAIs were determined to be at the dorsal roots as their scores were higher than the cutoff and did not indicate motor deficits. The MAIs of the anatomically identified anterior and posterior root CMAPs were found to have a cutoff value of <0.4 mA in the cervical lesions. Similar MAI cutoffs were also applicable to thoracolumbar lesions. Thus, CMAP may be useful in detecting anterior and posterior roots in spinal tumor surgery.

Application of unilateral biportal endoscopy technique to resect a thoracic spinal intradural extramedullary meningioma: technical report and review of the literature

BackgroundMeningiomas are common intradural extramedullary spinal tumors, which arise from arachnoid cap cells in the leptomeninges surrounding the brain or spinal cord. Sensory and motor dysfunction as well as pain were the most common presenting symptoms. Surgical resection remains the primary treatment for spinal intradural extramedullary meningiomas. Traditionally, spinal meningiomas excision requires longer skin incision, bilateral subperiosteal muscle stripping, and total laminectomy. We report a new technique for the treatment of thoracic spinal intradural extramedullary meningioma, which involves the use of unilateral biportal endoscopy (UBE) technique to resect the tumor, and reviewed and analyzed relevant literature.Case presentationA 69-year-old female patient presented with back pain accompanied by slowly progressive lower limb paresis, and severe pain in the right lower limb. Magnetic resonance imaging suggests a thoracic spinal intradural extramedullary meningioma. She underwent meningioma resection using UBE technique with complete recovery at the follow-up examination 3 months after surgery.ConclusionThis case confirmed the UBE technique can be a good choice for resection of spinal intradural extramedullary meningioma.

Intradural Extramedullary Spinal Tumors: A Clinical Study and Management without the Aid of Nerve Monitoring

Abstract Background: The incidence of primary spinal cord tumors is less and the true incidence is still not known and various studies are still being done. These tumors are benign and slow growing, and they generally present with pain – either radiculopathy or axial back pain or focal neurological deficits due to the loss of roots, myelopathy from spinal cord compression, or cauda equina symptoms due to chronic compression. Early diagnosis and operation are gratifying as the lesions are mostly benign and can be completely resected as well as preservation of functionality if operated as early as possible. Although rare, an inadvertent neurological injury during surgery is a concerning complication that can potentially be prevented with the assistance of intraoperative nerve monitoring (IONM). This technology enables real-time assessment of spinal cord function by providing feedback from sensory tracts, motor tracts, and individual nerve roots. However, the definitive requirement for IONM in the treatment of a highly curable condition is still under consideration. Objective: our study aims at studying the clinical features of intradural extramedullary tumors and their operative management without nerve monitoring. Material and Methods: Patients with intradural extramedullary (IDEM) spinal cord tumors who fit the inclusion criteria and who were willing to investigations, surgical procedures, and follow up were enrolled in the study, and consent was obtained. Patient assessment was done clinically by McCormick’s Scale and radiologically by magnetic resonance imaging. Patients who underwent operation were followed up. The data was collected and analysed using SPSS software. Results: Nineteen patients were enrolled in the study. The age group ranged from 6 years to 79 years. There were 13 females and 6 males in the study group. The common presenting complaints were backache and upper and lower limb pain. Nine out of the 19 patients underwent operative procedures after thorough radiological and clinical evaluation. Histopathology showed five cases of schwannoma and four cases of meningioma. The mean McCormick’s Scale preoperatively was 4.11, whereas postoperatively, it was 3.10. The operative procedures were performed without the aid of IONM, yet there were no inadvertent intraoperative injuries and postoperative outcomes were good. Our study data were comparable with other studies. Conclusion: IDEM tumors, though technically challenging to operate, have excellent results in terms of outcomes due to their benign characteristics as well as complete resectability. Therefore, it is essential to conduct a comprehensive examination and imaging for patients experiencing backaches and weakness. Following a careful evaluation, early surgical intervention should be considered, as the timeliness of the surgery contributes to enhanced outcomes. The unavailability of nerve monitoring did not portend any added risk of surgery if done meticulously though its aid would make the operative procedure safer and gross resection better.

Intraoperative AI-based Analysis and Diagnosis of Intradural Extramedullary Spinal Tumors by Stimulated Raman Histology

Intraoperative AI-based Analysis and Diagnosis of Intradural Extramedullary Spinal Tumors by Stimulated Raman Histology

The efficacy of intraoperative neuromonitoring, including triggered electromyography, in intradural extramedullary spine tumors: a successful case study

The efficacy of intraoperative neuromonitoring, including triggered electromyography, in intradural extramedullary spine tumors: a successful case study

Pediatric Dorsal Intradural Extra-Medullary Epidermoid Cyst (Non-Dysraphic): An Illustrative Case with Literature Review

A spinal epidermoid cyst is a rare congenital tumour that may be associated with spinal dysraphism. Congenital spinal epidermoid cysts without spinal dysraphism are rare. Here we are reporting a rare and interesting case of thoracic Intradural extra-medullary epidermoid cyst not associated with spinal dysraphism. Epidermoid cysts (EC) represent less than 1.0% and are rarely seen as an intradural extra-medullary spinal cord tumor. Preoperative Clinico- Radiological assumption is important for surgical planning. Journal of National Institute of Neurosciences Bangladesh, January 2023;9(1):88-95

Surgical resection of an intradural extramedullary spinal tumor.

Large ventrally located spinal meningiomas are typically resected via a posterolateral or lateral approach. Optimal outcomes are associated with good preoperative functional status (i.e., modified McCormick grade < 4), while recurrence rates may be predicted by degree and quality of resection (i.e., low Simpson grade). This video describes the operative techniques for resection of a large ventral C2 intradural extramedullary meningioma in a 71-year-old male presenting with hemibody sensory loss and abnormal gait. A paramedian approach was performed, allowing for adequate exposure and gross-total resection. The patient was discharged on postoperative day 2 and showed near-complete resolution of sensory deficits.

Tandem resection of multiple spinal schwannomas.

This video depicts the resection of three separate intradural extramedullary spinal tumors performed under the same anesthetic. Neuromonitoring was used to identify motor nerve roots, and laminoplasty was performed at the thoracolumbar junction to preserve alignment and minimize the risk of postoperative CSF leak.

Does the degree of preoperative gait disturbance remain after tumor resection in patients with intradural extramedullary spinal cord tumors?

Retrospective comparative study. This study aimed to determine whether the degree of preoperative gait disturbance remains following surgical resection in patients with intradural extramedullary spinal cord tumors (IDEMSCTs), and to investigate any factors that may influence poor improvement in postoperative gait disturbance. The single institution in Japan. In total, 78 IDEMSCTs patients who required surgical excision between 2010 and 2019 were included. According to the degree of preoperative gait disturbance using modified McCormick scale (MMCS) grade, they were divided into the Mild and Severe groups. The mean postoperative follow-up period was 50.7 ± 17.9 months. Data on demographic and surgical characteristics were compared between the two groups. There was no significant difference in terms of age at surgery, sex, tumor size, surgical time, estimated blood loss, tumor histopathology, and postoperative follow-up period between the Mild and Severe groups. At the final follow-up, 84.6% of IDEMSCTs patients were able to walk without support. Gait disturbance improved after surgery in most of the patients with preoperative MMCS grades II-IV, but remained in approximately half of patients with preoperative MMCS grade V. Age at surgery was correlated with poor improvement in postoperative gait disturbance in the Severe group. Regardless of the degree of preoperative gait disturbance, it improved after tumor resection in most of the IDEMSCTs patients. However, in the preoperative MMCS grade III-V cases, older age at surgery would be an important factor associated with poor improvement in postoperative gait disturbance.

Impact of Preoperative Motor Status for the Positive Predictive Value of Transcranial Motor-Evoked Potentials Alerts in Thoracic Spine Surgery: A Prospective Multicenter Study by the Monitoring Committee of the Japanese Society for Spine Surgery and Related Research.

Prospective multicenter study. To investigate the validity of transcranial motor-evoked potentials (Tc-MEP) in thoracic spine surgery and evaluate the impact of specific factors associated with positive predictive value (PPV). One thousand hundred and fifty-six cases of thoracic spine surgeries were examined by comparing patient backgrounds, disease type, preoperative motor status, and Tc-MEP alert timing. Tc-MEP alerts were defined as an amplitude decrease of more than 70% from the baseline waveform. Factors were compared according to preoperative motor status and the result of Tc-MEP alerts. Factors that showed significant differences were identified by univariate and multivariate analysis. Overall sensitivity was 91.9% and specificity was 88.4%. The PPV was significantly higher in the preoperative motor deficits group than in the preoperative no-motor deficits group for both high-risk (60.3% vs 38.3%) and non-high-risk surgery groups (35.1% vs 12.8%). In multivariate logistic analysis, the significant factors associated with true positive were surgical maneuvers related to ossification of the posterior longitudinal ligament (odds ratio = 11.88; 95% CI: 3.17-44.55), resection of intradural intramedullary spinal cord tumor (odds ratio = 8.83; 95% CI: 2.89-27), preoperative motor deficit (odds ratio = 3.46; 95% CI: 1.64-7.3) and resection of intradural extramedullary spinal cord tumor (odds ratio = 3.0; 95% CI: 1.16-7.8). The significant factor associated with false positive was non-attributable alerts (odds ratio = .28; 95% CI: .09-.85). Surgeons are strongly encouraged to use Tc-MEP in patients with preoperative motor deficits, regardless of whether they are undergoing high-risk spine surgery or not. Knowledge of PPV characteristics will greatly assist in effective Tc-MEP enforcement and minimize neurological complications with appropriate interventions.