Upstream Effects: Intraoperative Migration of Intradural Extramedullary Tumor After Non-Adjacent Level Stenosis Decompression

A 74-year-old man with back pain, foot numbness, and hip/thigh radiculopathy was found to have an L1-L2 intradural extramedullary neoplasm and severe L4-L5 stenosis. L4-L5 minimally invasive laminectomy for decompression and concomitant L1-L2 minimally invasive laminectomy for tumor resection were planned. L4-L5 laminectomy was completed first followed by the L1-L2 laminectomy. On extensive intradural exploration at L1-L2, no neoplasm was found. Immediate postoperative imaging showed that the intradural extramedullary tumor had migrated caudally by nearly a complete spinal level, presumably due to changes in cerebrospinal fluid pressure and resultant shift in intradural contents after the L4-L5 laminectomy. Successful resection of the intradural extramedullary tumor was performed, with improvement in the patient's symptoms.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

This study demonstrates that exoscope-assisted surgery for spinal intradural extramedullary tumors is comparable in safety and effectiveness to traditional microscopic surgery.

Intraoperative High-Resolution Color-Coded Ultrasound to Identify the Posterior Median Sulcus for Midline Myelotomy in Intramedullary Spinal Cord Surgery

A 14-year-old boy presented with a 2-year history of slowly increasing weakness and atrophy in the right forearm and leg. Magnetic resonance imaging (MRI) revealed an intramedullary diffusely infiltrating lateralized tumor at C3-7. An extended biopsy was planned. After laminotomy and durotomy, the swollen spinal cord was noted to be rotated by 45° with the right dorsal root entry zone being in the midline. A 15 MHz linear ultrasound probe was used to identify the midline by visualizing the dorsal median sulcal vein within the midline raphe. A myelotomy was made in that zone without deterioration of somatosensory evoked potentials (SEPs) and an extended biopsy was performed. Histological examination revealed a pilocytic astrocytoma. Modern intraoperative high-resolution color-coded ultrasound enables the identification of the midline in intramedullary spinal cord lesions even when the spinal cord anatomy is distorted.

Resection of an Intradural Intramedullary C7-T1 Tumor: Technical Nuances and Complication Management

Primary spinal cord tumors are relatively rare, comprising approximately 4%-16% of all tumors originating from the central nervous system. These tumors are anatomically separable into 2 broad categories: intradural intramedullary and intradural extramedullary. Intramedullary tumors are composed predominantly of gliomas (infiltrative astrocytoma) and ependymomas.1-4 The primary treatment approach for these tumors is surgical resection, aiming to preserve neurologic function.5-9 In Video 1, the authors showcase a step-by-step approach for microsurgical resection of a primary spinal ependymoma, with emphasis on microsurgical technique and utility of adjunct equipment, such as intraoperative ultrasound and neuromonitoring.10,11 The patient consented to the procedure.

Comparison of machine learning algorithms for the classification of spinal cord tumor

Spinal cord Tumor has been characterized as a heterogeneous disease consisting of many different subtypes. The early diagnosis and prognosis of a cancer type have become a necessity in cancer research, as it can facilitate the subsequent clinical management of patients. The importance of classifying cancer patients into Bening or malignant has led many re- search teams, from the biomedical and the bioinformatics field, to study the application of machine learning (ML) methods. Therefore, these techniques have been utilized as an aim to model the progression and treatment of cancerous conditions. In addition, the ability of ML tools to detect key features from complex datasets reveals their importance. A variety of these techniques, Logistic regression, Support Vector Machines (SVMs), Decision Trees (DTs), Random forest classifier(RFs) have been widely applied in cancer research for the development of predictive models, resulting in effective and accurate decision making. Even though it is evident that the use of ML methods can improve our understanding of cancer progression, an appropriate level of validation is needed in order for these methods to be considered in the everyday clinical practice. In this work, we have discussed a predictive model based on various supervised ML techniques.

Primary extraskeletal intradural Ewing sarcoma with acute hemorrhage: a case report and review of the literature

BACKGROUND

Spinal cord tumors present a challenge in diagnosis and treatment due to their varied histopathological characteristics. While Ewing sarcoma is a rare malignant tumor typically originating from skeletal bone, cases of primary intradural extraskeletal Ewing sarcoma are exceptionally rare. The similarity of its presentation to other spinal tumors further complicates its identification and management.

CASE PRESENTATION

We report a case of a 58-year-old Palestinian male with intradural extraskeletal lumbar Ewing sarcoma. The patient initially presented with lower back pain and bilateral S1 radiculopathy, with more severe symptoms on the left side. Magnetic resonance imaging revealed a 7 cm oval-shaped mass with homogeneous contrast enhancement, obstructing the spinal canal from L3/L4 to L5/S1 levels. Initially, a myxopapillary ependymoma was suspected, but the patient's sensory and motor functions suddenly deteriorated during hospitalization. Repeat magnetic resonance imaging indicated heterogeneous contrast enhancement, indicating acute intratumoral hemorrhage. Consequently, the patient underwent emergent L3-L5 laminotomy, with successful gross total resection of the tumor. Histopathological and immunohistochemical analyses confirmed the diagnosis of intradural extraskeletal Ewing sarcoma. Adjuvant therapy was administered to minimize the risk of local recurrence or distant metastasis. A systematic review of relevant literature, along with retrospective analysis of medical records, operative reports, radiological studies, and histopathological findings of similar cases, was also conducted.

CONCLUSIONS

Intradural extraskeletal Ewing sarcoma is an infrequently encountered condition in adult patients, emphasizing the importance of considering it in the differential diagnosis of spinal tumors. Surgeons must possess a comprehensive understanding of this rare entity to ensure accurate staging and optimal management, particularly in the early stages when prompt intervention may improve prognosis.

Complex lumbosacral spinal cord lipomas: A longitudinal study on outcomes from a Singapore children's hospital

BACKGROUND

Total/near-total resection (TR/NTR) of complex lumbosacral lipomas (CSL) is reported to be associated with better long-term functional outcomes and lower symptomatic re-tethering rates. We report our institutional experience for CSL resection in affected children.

METHODS

This is a single-institution, retrospective study. Inclusion criteria consist of patients with CSL with dorsal, transitional and chaotic lipomas based on Pang et al's classification. The study population is divided into 2 groups: asymptomatic patients with a normal preoperative workup referred to as 'prophylactic intent' and 'therapeutic intent' for those with pre-existing neuro-urological symptoms. Primary aims are to review factors that affect post-operative clean intermittent catheterization (CIC), functional outcomes based on Necker functional score (NFS), and re-tethering rates.

RESULTS

122 patients were included from 2000 to 2021. There were 32 dorsal lipomas (26.2 %), 74 transitional lipomas (60.7 %), and 16 chaotic lipomas (13.1 %). 82 % patients achieved TR/NTR. Favourable NFS at 1-year was 48.2 %. The re-tethering rate was 6.6 %. After multivariable analysis, post-operative CIC was associated with median age at surgery (p = 0.026), lipoma type (p = 0.029), conus height (p = 0.048) and prophylactic intent (p < 0.001). Next, extent of lipoma resection (p = 0.012) and the post-operative CSF leak (p = 0.004) were associated with re-tethering. Favourable NFS was associated with lipoma type (p = 0.047) and prophylactic intent surgery (p < 0.001).

CONCLUSIONS

Our experience shows that TR/NTR for CSL is a feasible option to prevent functional deterioration and re-tethering. Efforts are needed to work on factors associated with post-operative CIC.

Spinal intramedullary uterine carcinosarcoma metastasis

Intramedullary spinal cord metastases (ISCM) are a rare and challenging manifestation of metastatic cancer that have devastating impacts on the individual's neurological function, survival expectancy and overall quality of life. Given the rarity and poor prognosis, there is a lack of consensus in management. Uterine carcinosarcoma itself is a rare cancer, accounting for less than 3% of all uterine cancers. It carries a poor prognosis, with only one-third of patients surviving beyond 5 years. There are no previous reports of uterine carcinosarcoma metastases to the spinal cord. Here, we present the case of a woman in her late 70s with a uterine carcinosarcoma intramedullary metastasis that was refractory to radiotherapy treatment and responded favourably to surgical debulking.

Spinal Cord Neoplasms

OBJECTIVE

This article discusses the diagnostic approach to patients with suspected neoplasms of the spinal cord and reviews the most common primary and metastatic spinal neoplasms and their presentations.

LATEST DEVELOPMENTS

Neoplasms of the spinal cord are rare entities that can involve the spinal cord parenchyma, the dura and leptomeninges, or the extradural space. The most common intramedullary spinal cord neoplasms are primary spinal cord tumors, including ependymomas, pilocytic astrocytomas, and diffuse midline gliomas. The most common primary neoplasms of the spine are intradural extramedullary spinal meningiomas, whereas primary neoplasms of the leptomeninges are rare. Advances in molecular characterization of spinal cord tumors and recent clinical trials of these rare entities are expanding the repertoire of systemic therapy options for primary spinal cord neoplasms. Metastases to the spine most often affect the extradural space. Metastatic epidural spinal cord compression is a neurologic emergency that requires a rapid, multidisciplinary response to preserve neurologic function.

ESSENTIAL POINTS

Neurologists should understand the diagnostic approach to neoplasms of the spinal cord. Knowledge of the most common spinal cord neoplasms will allow for appropriate management and optimal patient care.

Giant Myxopapillary Ependymoma with Multi-Site Neural Axis Metastases: A Rare Case with Suboptimal Outcome

BACKGROUND Myxopapillary ependymoma is a rare type of slow-growing tumor that mainly occurs in the spinal cord, particularly in the region of the conus medullaris and the cauda equina. It originates from the ependymal glial cells found in the filum terminale. CASE REPORT We present a clinical case of a 44-year-old male patient who presented with symptoms of non-specific pain in the lower back persisting for the past 2 years. He did not report any specific neurological deficits or radicular symptoms. Unenhanced MRI of the lumbar spine showed a giant intradural, extramedullary, heterogenous, expansive tumor at the level L1-S4 with erosion of the sacral bone and invasion of presacral tissue. Based on its characteristic localization and growth pattern, suspicion arose for myxopapillary ependymoma. Biopsy confirmed the initial diagnosis. Partial resection of the tumor with laminectomy and laminoplasty was deemed necessary. Preoperative neural axis MRI showed contrast-enhancing lesions in the cerebellum and the cervical and thoracic spine; therefore, adjuvant radiation therapy was administered. Following the surgery, the patient experienced intermittent episodes of neurological deficits and required physiotherapy. Control MRI a year after the operation showed tumor growth and more metastases along the neural axis. CONCLUSIONS Complete surgical excision of the tumor is the preferred treatment approach, but there is a risk of recurrence even after total excision, so radiotherapy is recommended to minimize the risk of recurrence. Prior to surgery, it is essential to conduct MRI/PET/CT of the head and spine to assess the possibility of metastases.

A feline spinal dermoid cyst treated with surgical intervention

A 5-year-old neutered female mixed cat presented with reduced activity and ataxia of the hind limbs. Computed tomography and magnetic resonance imaging revealed an extradural mass compressing the spinal cord on the dorsal aspects from the 7th to 8th thoracic vertebra. Dorsal laminectomy was performed on the 7-8th thoracic vertebra and the cyst was totally removed, giving full resolution of the clinical signs. The cyst was diagnosed as a dermoid cyst. To our knowledge, this is the first report of feline dermoid cyst compressing the spinal cord that was diagnosed antemortem. The prognosis is favorable when the cyst is completely resected.

Development of a novel prediction model for differential diagnosis between spinal myxopapillary ependymoma and schwannoma

Spinal myxopapillary ependymoma (MPE) and schwannoma represent clinically distinct intradural extramedullary tumors, albeit with shared and overlapping magnetic resonance imaging (MRI) characteristics. We aimed to identify significant MRI features that can differentiate between MPE and schwannoma and develop a novel prediction model using these features. In this study, 77 patients with MPE (n = 24) or schwannoma (n = 53) who underwent preoperative MRI and surgical removal between January 2012 and December 2022 were included. MRI features, including intratumoral T2 dark signals, subarachnoid hemorrhage (SAH), leptomeningeal seeding, and enhancement patterns, were analyzed. Logistic regression analysis was conducted to distinguish between MPE and schwannomas based on MRI parameters, and a prediction model was developed using significant MRI parameters. The model was validated internally using a stratified tenfold cross-validation. The area under the curve (AUC) was calculated based on the receiver operating characteristic curve analysis. MPEs had a significantly larger mean size (p = 0.0035), higher frequency of intratumoral T2 dark signals (p = 0.0021), associated SAH (p = 0.0377), and leptomeningeal seeding (p = 0.0377). Focal and diffuse heterogeneous enhancement patterns were significantly more common in MPEs (p = 0.0049 and 0.0038, respectively). Multivariable analyses showed that intratumoral T2 dark signal (p = 0.0439) and focal (p = 0.0029) and diffuse enhancement patterns (p = 0.0398) were independent factors. The prediction model showed an AUC of 0.9204 (95% CI 0.8532-0.9876) and the average AUC for internal validation was 0.9210 (95% CI 0.9160-0.9270). MRI provides useful data for differentiating spinal MPEs from schwannomas. The prediction model developed based on the MRI features demonstrated excellent discriminatory performance.

Metameric pruritus as the sole manifestation of an intramedullary tumor in a toddler

An 18-month-old child presented with persistent pruritus and excoriation involving the right T9 and T10 dermatomes. She did not exhibit any other dermatological or neurological anomalies. Based on magnetic resonance imaging investigation of the spine, T8 ganglioglioma was diagnosed and surgically removed resulting in resolution of the pruritus within a few days. This observation underlines the importance of neuroimaging in patients presenting with metameric pruritus without specific skin lesions, especially in young children.

[Laser fluorescence spectroscopy and navigation in surgical treatment of spinal tumors: a systematic review]

The main problem in microsurgical resection of spinal cord tumors is excessive surgical aggression. The last one often leads to unsatisfactory clinical and neurological outcomes. Laser fluorescence spectroscopy is a modern neurosurgical approach to distinguish tumor boundaries even if standard visible fluorescence techniques are ineffective.

OBJECTIVE

To evaluate the effectiveness of laser fluorescence spectroscopy alone or in combination with visual 5-ALA fluorescence for improvement of safety and quality of resection, as well as intraoperative diagnosis.

MATERIAL AND METHODS

Searching for literature data was carried out in accordance with the PRISMA recommendations. The authors reviewed articles independently of each other. These data were systematized.

RESULTS

Laser fluorescence spectroscopy is valuable to identify fragments of intramedullary ependyomas in 86% of cases, while visual fluorescence only in 81% of cases. Advisability of this technique for low-grade astrocytomas is still unclear and requires further study. Its effectiveness is 87.5% for extramedullary meningiomas. Neuromas do not accumulate 5-ALA. In addition, this method can be used to determine the boundaries of intradural metastatic lesions.

CONCLUSION

5-ALA fluorescence is a safe and useful intraoperative method for identifying tumor tissue and resection margins in patients with intramedullary or infiltrative extramedullary spinal cord tumors. Visual fluorescence combined with laser spectroscopy is a perspective method for intraoperative visualization of tumor remnants. This approach can improve safety and postoperative outcomes while maintaining resection quality.

Sporadic Spinal Hamartoma in Adults: A Rare Pathologic Entity

BACKGROUND

Sporadic spinal hamartomas in adults are extremely rare tumor-like lesions, without defined guidelines of treatment. The aim of this study is to investigate the peculiar features of this pathologic entity to support a more accurate diagnosis and management.

METHODS

A comprehensive and detailed literature review of sporadic spinal hamartomas in adults, including a personal case, was performed. Demographic (sex and age), clinical (presenting symptoms), radiologic and pathologic (size, localization, dural and spinal cord relationship of lesion) features, as well as treatment (time to surgery, extent of resection, perioperative and postoperative complications) and outcome (clinical) data were analyzed.

RESULTS

Seven studies, including 7 patients, were eligible for the review. A personal case was also added. Sporadic adult spinal hamartomas equally affect males and females, in a range of age from 18 to 75 years; sensory radicular deficits were detected in all patients at clinical onset; thoracic segment (4/8) of the spine and intradural compartment (6/8) were most involved. All patients underwent surgery and just one experimented postoperative complication; gross total resection was achieved in only 3 patients, mainly in an extradural localization; clinical improvement at last follow-up was reported in all but 1 patient.

CONCLUSIONS

Spinal hamartomas in adults may sometimes account for progressive worsening of neurologic symptoms and lead to potentially irreversible neurologic deficit; therefore, prompt and adequate diagnosis and treatment are mandatory. Surgical resection represents the only curative treatment and is indicated for symptomatic lesions to achieve neurologic symptoms restoration or arrest/prevent their progressive deterioration.

Intraoperative mixed-reality spinal neuronavigation system: a novel navigation technique for spinal intradural pathologies

OBJECTIVE

The objective of this study was to assess the intraoperative accuracy and feasibility of 3D-printed marker-based mixed-reality neurosurgical navigation for spinal intradural pathologies.

METHODS

The authors produced 3D segmentations of spinal intradural tumors with neighboring structures by using combined CT and MRI, and preoperative registration of pathology and markers was successfully performed. A patient-specific, surgeon-facilitated application for mobile devices was built, and a mixed-reality light detection and ranging (LIDAR) camera on a mobile device was employed for cost-effective, high-accuracy spinal neuronavigation.

RESULTS

Mobile device LIDAR cameras can successfully overlay images of virtual tumor segmentations according to the position of a 3D-printed marker. The surgeon can visualize and manipulate 3D segmentations of the pathology intraoperatively in 3D.

CONCLUSIONS

A 3D-printed marker-based mixed-reality spinal neuronavigation technique was performed in spinal intradural pathology procedures and has potential to be clinically feasible and easy to use for surgeons, as well as being time saving, cost-effective, and highly precise for spinal surgical procedures.

Treatment of intramedullary spinal cord tumors: a modified Delphi technique of the North American Spine Society Section of Spine Oncology

OBJECTIVE

Intramedullary spinal cord tumors (IMSCTs) are rare tumors with heterogeneous presentations and natural histories that complicate their management. Standardized guidelines are lacking on when to surgically intervene and the appropriate aggressiveness of resection, especially given the risk of new neurological deficits following resection of infiltrative tumors. Here, the authors present the results of a modified Delphi method using input from surgeons experienced with IMSCT removal to construct a framework for the operative management of IMSCTs based on the clinical, radiographic, and tumor-specific characteristics.

METHODS

A modified Delphi technique was conducted using a group of 14 neurosurgeons experienced in IMSCT resection. Three rounds of written correspondence, surveys, and videoconferencing were carried out. Participants were queried about clinical and radiographic criteria used to determine operative candidacy and guide decision-making. Members then completed a final survey indicating their choice of observation or surgery, choice of resection strategy, and decision to perform duraplasty, in response to a set of patient- and tumor-specific characteristics. Consensus was defined as ≥ 80% agreement, while responses with 70%-79% agreement were defined as agreement.

RESULTS

Thirty-six total characteristics were assessed. There was consensus favoring surgical intervention for patients with new-onset myelopathy (86% agreement), chronic myelopathy (86%), or progression from mild to disabling numbness (86%), but disagreement for patients with mild numbness or chronic paraplegia. Age was not a determinant of operative candidacy except among frail patients, who were deemed more suitable for observation (93%). Well-circumscribed (93%) or posteriorly located tumors reaching the surface (86%) were consensus surgical lesions, and participants agreed that the presence of syringomyelia (71%) and peritumoral T2 signal change (79%) were favorable indications for surgery. There was consensus that complete loss of transcranial motor evoked potentials with a 50% decrease in the D-wave amplitude should halt further resection (93%). Preoperative symptoms seldom influenced choice of resection strategy, while a distinct cleavage plane (100%) or visible tumor-cord margins (100%) strongly favored gross-total resection.

CONCLUSIONS

The authors present a modified Delphi technique highlighting areas of consensus and agreement regarding surgical management of IMSCTs. Although not intended as a substitute for individual clinical decision-making, the results can help guide care of these patients. Additionally, areas of controversy meriting further investigation are highlighted.

Intraoperative View of a Multinodal, Paralysis-Inducing Spinal Melanocytoma: Case Report and Literature Review

Melanocytomas arising from the leptomeningeal melanocytes within the central nervous system are a rare occurrence, accounting for 0.06%-0.1% of brain tumors and having an incidence of 1/10 million people per year.1-14 Here, we describe the case of 68-year-old male presenting with bilateral lower extremity weakness progressing to paralysis and urinary incontinence (Video 1). Upon examination, this gentleman had no sensation below T11. Magnetic resonance imaging showed multiple contrast-enhancing lesions with a major intradural lesion at level T11 arising from the ventrolateral surface and causing severe spinal cord compression. The multifocal nature of this tumor further adds to its rarity. Interdisciplinary indication for surgical resection of the intradural lesion was made. This was accomplished through a T11 laminectomy and concomitant T11-12 stabilization with neuromonitoring. Pathologic analysis of the resected tumor identified an S100+, HMB45+, pigmented melanocytoma. No complications occurred during the procedure. The patient was discharged to rehabilitation with persistent neurologic deficits. Routine follow-up is indicated given the high rates of recurrence and the multiple remaining tumor nodules.14.

Non-dysraphic extramedullary intradural spinal lipoma with neurocutaneous melanocytosis

INTRODUCTION

Intradural spinal lipomas are very rare and constitute less than 1% of all spinal tumors. Such tumors are usually associated with spinal dysraphism and occur mostly in the lumbosacral or cervical region. Intradural spinal lipomas tends to be intramedullary or subpial. Meningeal melanocytoma is further rarer cases that comprise less than 0.1% of cases. These usually occur in the fifth or fifth decade and chances of malignant transformation are high.

CASE REPORT

Here, we report an extremely rare case (first to the best of our knowledge) of a 9 years female child who presented to us with rapid progressing paraparesis. She was operated and found to have an intradural purely extramedullary spinal lipoma without spinal dysraphism. Moreover, she had melanin pigment deposits all over her meninges which is further rare. On presentation, the patient was bedridden but after surgery, the patient improved and could walk without support.

CONCLUSIONS

To the best of our knowledge, this is the first case of spinal cord lipoma in dorsal location along with melanin pigments in the meninges. We discuss the pathogenesis, presentation and management of intradural extramedullary spinal lipomas.

The efficacy of preoperative diffusion tensor tractography on surgical planning and outcomes in patients with intramedullary spinal tumor

PURPOSE

The aim of this study was to investigate the efficacy of diffusion tensor tractography (DTT) of spinal cord on surgical planning and postoperative neurological outcomes in patients with spinal intramedullary tumors.

METHODS

The study was conducted retrospectively from the radiological and clinical data of our hospital database. Patients with intramedullary spinal cord tumors who underwent diffusion tensor imaging for spinal cord lesions were selected between 2019 and 2022. Demographic characteristics and intraoperative neurophysiological monitoring data were evaluated. The McCormick scale was used to grade the pre- and postoperative neurological status of the patients. The tumoral lesions were categorized into 3 types according to the fiber course on DTT.

RESULTS

Eleven patients were found to have radiological findings that were compatible with intramedullary tumor; eight (72.7%) of them ultimately underwent surgery following being approved as surgical candidates in the spinal diffusion tensor imaging studies. Six cases had Type 1, one case had Type 2, and 4 cases had Type 3 tumors according to the fiber course. All Type 1 tumors were classified as resectable and all of them were gross totally resected. Type 2 lesion that was rated as resectable by DTI was subtotally resected. Type 3 lesions were followed without surgery except the one with tumoral progression and neurological deficit. The postoperative neurological outcomes were compatible with intraoperative neurophysiological monitoring results.

CONCLUSION

Diffusion tensor imaging and tractography may be beneficial regarding the selection of patients suitable for surgery and in the subsequent surgical planning.

Cauda equina syndrome from intradural metastasis of a non-neural tumor: case report and review of literature

BACKGROUND

Cauda equina syndrome (CES) is a challenging condition and it can be caused by variable entities. Leptomeningeal carcinomatosis (LC) is a multifocal seeding of the leptomeninges by malignant cells and it is observed in 1-8% of patients with solid tumors. Diagnosis of intradural metastases of the cauda equina is often delayed due to the non-specific characteristics of this condition but also to the delay of presentation of many patients. Cauda equina metastases usually occur in advanced cancers, but rarely can be the first presentation of disease.

CASE DESCRIPTION

A 63-year-old man presented with 6 months history of low back pain and 20 d history of bilateral sciatica, hypoesthesia of the legs and the saddle, flaccid paraparesis and bowel incontinence determine by multiple nodular small lesions on the entire cauda equina with contrast-enhancement. Total-body CT showed a millimetric lesion at the lung. The patient underwent L2-L5 laminectomy and subtotal removal and histological examination showed a small cell lung carcinoma metastasis.

CONCLUSIONS

In the literature, 54 cases of CES from non-CNS tumor metastasis are described. The diagnosis is challenging, back pain, with or without irradiation to the lower limbs, is the most frequently reported disturbance. In about 30% of patients there is no known malignancy and CES is the first clinical presentation. Treatment of choice is surgery, followed by radiotherapy and less frequently adjuvant chemotherapy. The surgical removal is almost always incomplete and functional outcome is often not satisfactory. Prognosis is poor.

Mobile cauda equina ependymoma, case report and literature review

The aim of this study was to describe a very rare presentation of ependymoma that can derive from intraoperative complications for surgeons and increased morbidity for the patients. Multiple cases of mobile cauda equina tumors leading to inadequate approach have been reported in the literature, however, the reports of ependymoma histology are very rare. This report describes the third adult case in recent years and a retrospective review of cases reported in the literature until today. We show the clinical and radiographic presentation of a 79 years old patient that presented a mobile cauda equina tumor in the preoperative image, who went to surgery for resection and arthrodesis, obtaining in post-operative histology the diagnostic of ependymoma. The preoperative image shows the migration of the tumor avoiding the wrong approach. The patient went to surgery for laminectomy, pedicular screw arthrodesis L1-S1, and tumor removal, obtaining a complete resection and confirmed histology diagnostic of ependymoma, unfortunately, the patient died five days after by a cardiac arrest. The recent literature reports only four cases of mobile ependymoma, two of them in pediatrics patients and just only two adult cases, which means this is the third adult case of an ependymoma. Mobile cauda equina ependymoma is a very rare neoplasm presentation but is an entity that can lead to mistakes in the approach and may be useful for the neurosurgeons who day per day treat this pathology beware of this possibility.

Dorsal column mapping in resection of intramedullary spinal cord tumors: a prospective comparison of two methods and neurological follow-up

PURPOSE

In surgery for intramedullary spinal cord tumors (imSCT), distortion of the anatomy challenges the visual identification of dorsal columns (DC) for midline myelotomy. Dorsal column mapping (DCM) and spinal cord stimulation (SCS) can identify DC neurophysiologically. We compare application and feasibility of both methods.

METHODS

Patients with surgically treated imSCT were prospectively included between 04/2017 and 06/2019. The anatomical midline (AM) was marked. SSEPs at the DC after stimulation of tibial/median nerve with an 8-channel DCM electrode and cortical SSEP phase reversal at C3/C4 after SCS using a bipolar concentric probe were recorded. Procedural and technical aspects were compared. Standardized neurological examinations were performed preoperatively, 1 week postoperatively and after more than 12 months.

RESULTS

The DCM electrode detected the midline in 9/13 patients with handling limitations in the remaining patients. SCS was applicable in all patients with determination of the midline in 9/13. If both recordings could be acquired (6/13), concordance was 100%. If baseline SSEPs were poor, both methods were limited. SCS was less time-consuming (p = 0.001), cheaper, and easier to handle. In 92% of cases, the AM and neurophysiologic midlines were concordant. After myelotomy, 3 patients experienced > 50% reduction in amplitude of SSEPs. Despite early postoperative worsening of DC function, long-term follow-up showed significant recovery and improvement in quality of life.

CONCLUSION

DCM and SCS may help confirm and correct the AM for myelotomy in imSCT, leading to a favorable long-term neurological outcome in this cohort. SCS evolved to be superior concerning applicability, cost-effectiveness, and time expenditure.

Laminectomy with Laminar Reconstruction for Resection of Intradural Tumors at the Thoracolumbar Junction: A Technical Note

OBJECTIVE

To introduce a new laminar reconstruction technique to treat primary spinal cord tumors.

METHODS

Laminectomy and laminoplasty techniques have been used to treat intradural spinal tumors. The advantage of laminectomy is its superior exposure of the spinal cord, whereas the advantage of laminoplasty is the reconstruction of the dorsal roof of the spine. In this technical note, we present a technique that combines a full laminectomy to maximize exposure, with a reconstructive technique to repair the lamina. This technique restores the posterior ligamentous complex to preserve spinal biomechanics.

RESULTS

In this illustrative case, a 55-year-old woman with severe back pain radiating to the right lower extremity was found to have an intradural tumor at the T12-L1 spinal level. Given the transitional level of the spine and potentially high biomechanical stresses on the posterior support structures, we used a T12 laminectomy to resect the tumor, followed by reconstruction using miniplates. The patient tolerated the surgery well, without any complications. She was discharged home and was doing well during the 3 months follow-up visit. Appropriate patient consent was obtained.

CONCLUSIONS

Laminectomy and laminar reconstruction allow maximum visualization and manipulation of the tumor, followed by restoration of the dorsal roof of the spinal ring, and is an effective technique for treating spinal cord tumors.

Surgical outcomes in instrumented surgery for dumbbell type spinal cord tumor -the comparison with non-instrumented surgery for spinal cord tumor

BACKGROUND

There is little information on outcomes for spinal cord tumor treated surgically with instrumentation. Analysis of surgical outcomes and complications in such cases is needed to develop generalizable conclusions and to help inform patients.

METHODS

The subjects were 41 patients treated with instrumentation surgery for dumbbell type tumor resection. Demographic data; tumor histology, level, and location; number of fused vertebra; use of a bilateral or hemilateral screw; operative time; EBL; TcMEP monitoring; lumbar subarachnoid drainage; duration of subfascial drainage; postoperative motor and sensory deficits; CSF leakage, implant-related complications; time for union of fused vertebra; salvage surgeries, and pre-/postoperative McCormick scale were obtained from medical records. Significant factors related to postoperative motor deficits were identified.

RESULTS

Postoperative motor deficit occurred in 9 cases (22.0%) and all recovered in 30 days after surgery. CSF leakage at 7 days and 2 years after surgery was subfascial (n = 31, n = 6) and subcutaneous (n = 3, n = 4). Cases with postoperative motor deficits more commonly had lower cervical lesions; those with CSF leakage had longer operative times; and those with delayed union had more use of hemilateral instrumentation.

CONCLUSION

In this study in 41 spinal cord tumors treated surgically with instrumentation, the rate of postoperative motor deterioration was 22.0%, and CSF leakage was found in 17.1%.

Magnetic resonance imaging findings of the primitive neuroectodermal tumour in lumbosacral spinal cord in a cat

A 5-year-old, castrated, male domestic short-haired cat presented with neurological deficits in the pelvic limbs, back pain and dysuria. Magnetic resonance imaging showed a mass lesion caudal to the L4 vertebrae. In addition, suspected haemorrhage was observed at the cranial aspect of the mass. There was no evidence to support the presence of extravertebral intrusion or vertebral body, osteolysis. Dorsal laminectomy and durotomy were performed to debulk the intraspinal mass. Histopathological and immunohistochemical assessment revealed a primitive neuroectodermal tumour (PNET). To our knowledge, this is the first report to describe the clinical and pathological features and imaging diagnosis of intraspinal PNET without extraspinal invasion in a cat.

Modified Unilateral Approach for Ventrally Located Spinal Tumors

Surgery on spinal tumors becomes challenging when the tumor is ventral to the spinal cord. Conventionally, we approach it posteriorly through bilateral laminectomy and rotate the cord after sectioning the dentate ligament and nerve roots. However, manipulating the cord can be hazardous, and a long bilateral laminectomy can be invasive. Meanwhile, a narrow operative field and a limited lateral viewing angle in a unilateral approach constrained the surgeon. To overcome these problems, we previously reported a technique of modified unilateral approach where we incised the skin and the fascia horizontally and placed a pair of retractors longitudinally.The current article reports our experience applying this approach in 15 patients with ventrally located spinal tumors. The approach was performed on 10 schwannomas, 2 meningiomas, and 3 others. We evaluated paraspinal muscle atrophy on postoperative magnetic resonance imaging.The modified unilateral approach provided an excellent surgical field for removing ventrally located tumors. Gross total removal was achieved in 11 patients (92% of benign tumors). No neurological complications occurred except for one case of transient weakness. We encountered no wound-related late complications such as pain or deformity. The reduction of the cross-sectional area of the paraspinal muscles on the approach side (compared to the nonapproach side) was 0.93 (95% confidence interval: 0.72-1.06), indicating 7% atrophy (statistically nonsignificant, p = 0.48).We believe this simple technique can be useful for removing spinal tumors located ventral to the spinal cord.

Malignant transformation of adult-onset pilocytic astrocytoma to diffuse leptomeningeal glioneuronal tumor within the thoracic spine: a case report and review of the literature

We describe a 31-year-old male who presented with progressive myelopathy from a thoracic pilocytic astrocytoma (PA). Following multiple recurrences and resections, 10 years after his index surgery, pathology revealed diffuse leptomeningeal glioneuronal tumor (DLGNT) with high-grade features. We discuss his clinical course, management, histopathological findings, and present a comprehensive review of spinal PA undergoing malignant transformation in adults and adult-onset spinal DLGNT. To our knowledge, we present the first reported case of adult-onset spinal PA malignant transformation to DLGNT. Our case adds to the paucity of clinical data characterizing such transformations and highlights the importance of developing novel management paradigms.

The Role of MRI in the Diagnosis of Spinal Cord Tumors

Spinal cord tumors are uncommon, and its multiple representatives not always have pathognomonic characteristics, which poses a challenge for both patients and caring physicians. The radiologist performs an important role in recognizing these tumors, as well as in differentiating between neoplastic and non-neoplastic processes, supporting clinical and surgical decision-making in patients with spinal cord injury. Magnetic Resonance Imaging (MRI) assessment, paired with a deep understanding of the various patterns of cord involvement allied to detailed clinical data can provide a diagnosis or significantly limit the differential diagnosis in most cases. In this article, we aim to review the most common and noteworthy intramedullary and extramedullary spinal tumors, as well as some other tumoral mimics, with an emphasis on their MRI morphologic characteristics.

Surgery for spina bifida occulta: spinal lipoma and tethered spinal cord

The technical evolution of the surgery for spina bifida occulta (SBO) over the course of a half-century was reviewed with special foci placed on the spinal lipoma and tethered spinal cord. Looking back through history, SBO had been included in spina bifida (SB). Since the first surgery for spinal lipoma in the mid-nineteenth century, SBO has come to be recognized as an independent pathology in the early twentieth century. A half-century ago, the only option available for SB diagnosis was the plain X-ray, and pioneers of the time persevered in the field of surgery. The classification of spinal lipoma was first described in the early 1970s, and the concept of tethered spinal cord (TSC) was proposed in 1976. Surgical management of spinal lipoma with partial resection was the most widely practiced approach and was indicated only for symptomatic patients. After understanding TSC and tethered cord syndrome (TCS), more aggressive approaches became preferred. A PubMed search suggested that there was a dramatic increase of publications on the topic beginning around 1980. There have been immense academic achievements and technical evolutions since then. From the authors' viewpoint, landmark achievements in this field are listed as follows: (1) establishment of the concept of TSC and the understanding of TCS; (2) unraveling the process of secondary and junctional neurulation; (3) introduction of modern intraoperative neurophysiological mapping and monitoring (IONM) for surgery of spinal lipomas, especially the introduction of bulbocavernosus reflex (BCR) monitoring; (4) introduction of radical resection as a surgical technique; and (5) proposal of a new classification system of spinal lipomas based on embryonic stage. Understanding the embryonic background seems critical because different embryonic stages bring different clinical features and of course different spinal lipomas. Surgical indications and selection of surgical technique should be judged based on the background embryonic stage of the spinal lipoma. As time flows forward, technology continues to advance. Further accumulation of clinical experience and research will open the new horizon in the management of spinal lipomas and other SBO in the next half-century.

Dural reconstruction following resection of ventral and lateral spinal cord meningiomas: Fenestrated Durotomy with Oversized Graft technique

BACKGROUND

Meningiomas, although benign, often require complete resection due to their tendency for recurrence. However, dural reconstruction poses significant challenges, especially in the case of ventral meningiomas. While some reports have highlighted the usefulness of dural reconstruction using an artificial dura mater, no studies have yet confirmed dural canal enlargement through MRI post-surgically. This study aimed to assess the effectiveness of the Fenestrated Durotomy with Oversized Graft (FDOG) technique in cases of meningiomas and other intradural extramedullary tumors and evaluated dural canal dilation through MRI after using an artificial dura mater.

METHODS

This retrospective case series included 8 patients who underwent combined resection of intradural extramedullary tumors and dural repair using the FDOG technique. An artificial dura mater larger than that resected was inserted into the dural defect resulting from complete tumor resection on the ventral or lateral side of the spinal cord. The new dura mater was secured with a single dorsal suture. The dural incision was closed using watertight sutures following standard procedure. Measurement of the extent of dural canal enlargement was achieved via pre- and postoperative MRI scans.

RESULTS

None of the patients required additional treatments or lumbar drainage. All achieved independent ambulation without complications, and imaging tests indicated satisfactory dural expansion without signs of cerebrospinal fluid leakage.

CONCLUSIONS

The proposed method for dural repair in cases involving large dural defects on the ventral or lateral side of the spinal cord was shown to be a straightforward and effective approach with minimal postoperative complications.

The evolution of spinal cord surgery: history, people, instruments, and results

INTRODUCTION

Spinal cord surgery has and always will be a challenging operation with satisfying results, but also with potentially devastating results. Over the last century, there has been an evolution in the way we perceive and conduct spinal cord surgery. The phenomenal evolution in technology from the very first x-ray pictures helps to localize the spinal pathology through the use of high-resolution MRI and ultrasonography that allows for high precision surgery with relatively minimal exposure.

METHODS

The advancements in the surgical technique and the utilization of neuromonitoring allow for maximal safe resection of these delicate and intricate tumors. We also are beginning to understand the biology of spinal cord tumors and vascular lesions, as in the recent 2021 WHO classification which identifies specific entities such as spinal ependymomas, MYCN-amplified, as separate entity from the other subtypes of ependymomas. Surgeons have also accepted the importance of maximal safe resection for most of the spinal cord pathologies rather than just performing biopsy and adjuvant treatment.

CONCLUSION

There have been significant advances since the first resection of an intramedullary tumor including diagnosis, imaging, and surgical technique for children. These advances have improved the prognosis and outcome in these children.

Spinal Schwannomas; Classification, Management And Outcomes

Schwannomas are benign tumours of the peripheral nerve sheath. When they occur in spine, they are most commonly found in intradural-extramedullary location. Surgery is the mainstay of treatment. Radiation has a limited role in the management of residual or recurrent lesions not suitable for surgery. Here we discuss the existing literature on the outcomes of spinal schwannoma after surgery.

Spinal anaplastic ganglioglioma

Anaplastic gangliogliomas of the spinal cord are extremely rare with only four cases reported in the literature. Here we present the case of a 22-year-old female who presented acutely with quadraparesis and urinary retention. Radiographic imaging demonstrated an intramedullary lesion within the cervical spine. She underwent a cervical laminectomy and resection of the lesion under neurophysiological monitoring. Post-operatively, she regained some function, but remained paraparetic. Histopathology demonstrated an anaplastic ganglioglioma (WHO Grade 3). She subsequently underwent radiotherapy. Following surgery, she remained stable and had MRC Grade 3 Power in all four limbs. Herein, we describe a previously undescribed case of cervical anaplastic ganglioglioma and review the existing literature.

Intramedullary Subependymoma Of Lower Thoracic Cord

Spinal subependymoma (SSE) is a rare intramedullary, benign tumour. Surgical excision isthe preferred approach. However, the interwoven pattern of neural tissue within the tumour dictates the extent of resection. Where gross total resection is linked with possible neurological deficits, subtotal resection or close observation may support better functional outcomes. The evidence for the management of SSE is based mostly on case reports. Herein, we review the existing literature regarding treatment options and clinical outcomes of spinal subependymoma.

Deep Learning for Noninvasive Assessment of H3 K27M Mutation Status in Diffuse Midline Gliomas Using MR Imaging

BACKGROUND

Determination of H3 K27M mutation in diffuse midline glioma (DMG) is key for prognostic assessment and stratifying patient subgroups for clinical trials. MRI can noninvasively depict morphological and metabolic characteristics of H3 K27M mutant DMG.

PURPOSE

This study aimed to develop a deep learning (DL) approach to noninvasively predict H3 K27M mutation in DMG using T2-weighted images.

STUDY TYPE

Retrospective and prospective.

POPULATION

For diffuse midline brain gliomas, 341 patients from Center-1 (27 ± 19 years, 184 males), 42 patients from Center-2 (33 ± 19 years, 27 males) and 35 patients (37 ± 18 years, 24 males). For diffuse spinal cord gliomas, 133 patients from Center-1 (30 ± 15 years, 80 males).

FIELD STRENGTH/SEQUENCE

5T and 3T, T2-weighted turbo spin echo imaging.

ASSESSMENT

Conventional radiological features were independently reviewed by two neuroradiologists. H3 K27M status was determined by histopathological examination. The Dice coefficient was used to evaluate segmentation performance. Classification performance was evaluated using accuracy, sensitivity, specificity, and area under the curve.

STATISTICAL TESTS

Pearson's Chi-squared test, Fisher's exact test, two-sample Student's t-test and Mann-Whitney U test. A two-sided P value <0.05 was considered statistically significant.

RESULTS

In the testing cohort, Dice coefficients of tumor segmentation using DL were 0.87 for diffuse midline brain and 0.81 for spinal cord gliomas. In the internal prospective testing dataset, the predictive accuracies, sensitivities, and specificities of H3 K27M mutation status were 92.1%, 98.2%, 82.9% in diffuse midline brain gliomas and 85.4%, 88.9%, 82.6% in spinal cord gliomas. Furthermore, this study showed that the performance generalizes to external institutions, with predictive accuracies of 85.7%-90.5%, sensitivities of 90.9%-96.0%, and specificities of 82.4%-83.3%.

DATA CONCLUSION

In this study, an automatic DL framework was developed and validated for accurately predicting H3 K27M mutation using T2-weighted images, which could contribute to the noninvasive determination of H3 K27M status for clinical decision-making.

EVIDENCE LEVEL

2 Technical Efficacy: Stage 2.

Intradural extramedullary tumors. Retrospective cohort study assessing prognostic factors for functional outcome in adult patients

OBJECTIVE

The purpose of this study is to analyze a series of patients with intradural extramedullary tumors (IDEM) and assess factors that may modify or determine the final long term outcome and management.

MATERIALS AND METHODS

Single Center, retrospective study of a series of surgical patients with IDEM lesions from our Institution operated between 2010 and 2021. Patients with less than 6 months of follow up were excluded. Several preoperative demographics, clinical, imaging and surgical features, as well as histopathology, recurrence and adjuvancy were assessed. Patients' final clinical outcome was categorized using the McCormick scale.

RESULTS

A total of 203 patients with a mean follow-up of 30.50 months (range 6-130) were included. 57.64% of the analyzed population was female and the mean age was 50.51 years. The most frequent location of the tumors was dorsal (34.98%) followed by the lumbar region (32.02%). Total resection was achieved in 84.24% of cases, and the most frequent histopathology was Schwannoma (36.45%), followed by Meningioma (30.05%). Pain was the most usual initial symptom (63.05%). In our analysis, functional outcome after surgery was associated with statistical significance with preoperative McCormick grade, tumor type, EOR and postoperative complications such as hematoma and sphincter involvement.

CONCLUSION

The management of these lesions depends on many factors. It is worthy of mention that clinical presentation, EOR, histopathology and postoperative complications have shown significant prognostic value for the final outcome. Early treatment with the intention of achieving GTR when possible, using carefully tailored approaches, should be considered before the onset of significant symptoms.

Advances in Imaging Modalities for Pediatric Brain and Spinal Cord Tumors

BACKGROUND

Neuroimaging has evolved from anatomical imaging toward a multi-modality comprehensive anatomical and functional imaging in the past decades, important functional data like perfusion-weighted imaging, permeability imaging, diffusion-weighted imaging (DWI), and diffusion tensor imaging (DTI), tractography, metabolic imaging, connectomics, event-related functional imaging, resting state functional imaging, and much more is now being offered.

SUMMARY

Precision diagnostics has proven to be essential for precision treatment. Many minimal invasive techniques have been developed, taking advantage of digital subtraction angiography and interventional neuroradiology. Furthermore, intraoperative CT and/or MRI and more recently MR-guided focused ultrasound have complemented the diagnostic and therapeutic armamentarium.

KEY MESSAGES

In the current manuscript, we discuss standard imaging sequences including advanced techniques like DWI, DTI, susceptibility-weighted imaging, and 1H magnetic resonance spectroscopy, various perfusion weighted imaging approaches including arterial spin labeling, dynamic contrast enhanced imaging, and dynamic susceptibility contrast imaging. Pre-, intra, and postoperative surgical imaging including visualize imaging will be discussed. The value of connectomics will be presented for its value in neuro-oncology. Minimal invasive therapeutic possibilities of interventional neuroradiology and image-guided laser ablation and MR-guided high-intensity-focused ultrasound will be presented for treatment of pediatric brain and spinal cord tumors. Finally, a comprehensive review of spinal cord tumors and matching neuropathology has been included.

Knowledge Review of Spinal Deformity and the Need for Fusion and Fixation following Treatment for Spinal Tumors among the Pediatric Age Group

BACKGROUND

Spinal tumors are rare pathology in the pediatric population. The tumors can be classified as extradural, intradural extramedullary, or intramedullary. Any of the spinal tumors can eventually lead to spinal deformity. The progressive spinal deformity can be part of the initial presentation or evolve on long follow-up, even years after the initial intervention and treatment.

SUMMARY

Management of spinal deformity associated with spinal tumors in children is not well defined. Patients with progressive symptoms and even neurological deficits need correction for their deformity when diagnosed. Patients that do not have pain or related neurological deficits should be evaluated for the severity of their deformity and followed long-term. Special consideration is needed for young patients who need multilevel surgery or have deformity at presentation.

KEY MESSAGES

When considering the need for instrumentation and fusion, the surgeon should consider the age of the patient, expected future growth of the spine, neurologic status, extent of initial deformity, and the number of vertebral levels involved by tumor. Providers should also consider how surgery may fix or prevent deformity, especially when instrumentation can affect imaging at follow-up.

Feasibility of multimodal intraoperative neurophysiological monitoring for extramedullary spinal cord tumor surgery in elderly patients

BACKGROUND/PURPOSE

Extramedullary spinal cord tumors (EMSCTs) are mostly benign tumors which are increasingly diagnosed and operatively treated in the elderly. While there are hints that multimodal intraoperative neurophysiological monitoring (IONM) could be influenced by age and age-related comorbidities, no study has ever systematically evaluated its feasibility and value for EMSCT surgery in elderly patients.

METHODS

We retrospectively evaluated all patients with microsurgical EMSCT resection under continuous multimodal IONM with SSEPs, MEPs and electromyography between 2016 and 2020. Epidemiological, clinical, imaging and operative/IONM records as well as detailed individual outcomes were analyzed and compared for the cohort < / ≥ 65 years.

RESULTS

Mean age was 45 years in cohort < 65 years (n = 109) and 76 years in cohort ≥ 65 years (n = 64), while baseline/operative characteristics did not significantly differ. Mean baseline SSEPs' latencies (left-right average) were significantly higher in the cohort ≥ 65 years for both median (20.9 ms vs. 22.1 ms; p < 0.01) and tibial nerve (42.9 ms vs. 46.1 ms; p < 0.01) without significant differences for SSEPs' amplitudes. Stimulation intensity to elicit intraoperative MEPs was significantly higher in the cohort ≥ 65 years (surrogate-marker: left-right-averaged quotient ID1-muscle/abductor-hallucis-muscle; 1.6 vs. 2.1; p < 0.001). Intraoperatively, SSEP and MEP monitoring were feasible in 99%/100% and 99%/98% for the cohort < / ≥ 65 years without significant differences in rates for significant IONM changes during surgery or postoperatively new sensorimotor deficits. Sensitivity of IONM was 29%/43%, specificity 99%/98%, positive and negative predictive values 67%/75% and 95%/93% for the cohort < / ≥ 65 years. Overall, age was no risk factor for IONM feasibility or rate of significant IONM changes.

DISCUSSION

Multimodal IONM is feasible/reliable for EMSCT surgery in elderly patients. An age-related prolongation of SSEPs' latencies and demand for higher stimulation intensities for MEPs' elicitation has to be considered.