Current Management and Treatment Modalities for Intramedullary Spinal Cord Tumors

Assessment of the Postoperative Progression in Patients With Intramedullary Spinal Cord Tumors Based on the Severity of Preoperative Gait Disturbance

Study DesignRetrospective comparative study.ObjectivesThis study aimed to determine whether the severity of preoperative gait disturbance remains after surgical resection in patients with intramedullary spinal cord tumors (IMSCTs), and to identify any factors influencing poor improvement in postoperative gait disturbance.MethodsThe study included a total of 128 patients with IMSCTs requiring surgical excision between 2006 and 2019. Based on the degree of preoperative gait disturbance assessed by the modified McCormick scale (MMCS) grade, patients were categorized into Mild (I-II) and Severe (III-V) groups. The mean postoperative follow-up period was 55.5 ± 34.3 months, and demographic and surgical characteristics were compared between the two groups.ResultsSignificant differences were observed in age at surgery, tumor location, tumor size, estimated blood loss, intraoperative motor-evoked potential disappearance, extent of resection, and tumor histopathology between the Mild and Severe groups. In the Mild group, at the final follow-up, only 7.3% of patients experienced improvement, 56.0% showed no changes, and 36.7% experienced deterioration. Conversely, in the Severe group, 26.3% of patients experienced improvement, 31.6% showed no changes, and 42.1% experienced deterioration. Tumor location and age at surgery were identified as factors correlated with poor improvement in postoperative gait disturbance in the Mild group.ConclusionsIrrespective of the preoperative gait disturbance degree, approximately 40% of patients with IMSCTs experienced deterioration in gait after tumor resection. For preoperative MMCS grade I-II cases, older age at surgery and thoracic IMSCTs would be important factors associated with poor improvement in postoperative gait disturbance.

Spinal ependymal tumors

Spinal ependymomas are strictly to be subdivided into intramedullary lesions and extramedullary lesions as they are histologically and genetically distinct. Whereas the intramedullary lesions (SPE) are assigned to the WHO grade 2 and very rarely grade 3, the extramedullary lesions or myxopapilary tumors (MPE) are only as recently also assigned to WHO grade 2. The major difference is that in general, an intramedullary lesion of grade 2 remains confined to the local site of origin, even when rarely recurring after complete resection. In contrast, the MPEs have the capacity to spread throughout the cerebrospinal fluid compartment but can also be controlled by cautious complete resection. We here review the clinical features of spinal ependymomas, contrasting the entities, and describe the treatment found best from the literature to manage these lesions including interdisciplinary approaches.

Intraoperative MRI: A Review of Applications Across Neurosurgical Specialties

Intraoperative MRI (iMRI) made its debut to great fanfare in the mid-1990s. However, the enthusiasm for this technology with seemingly obvious benefits for neurosurgeons has waned. We review the benefits and utility of iMRI across the field of neurosurgery and present an overview of the evidence for iMRI for multiple neurosurgical disciplines: tumor, skull base, vascular, pediatric, functional, and spine. Publications on iMRI have steadily increased since 1996, plateauing with approximately 52 publications per year since 2011. Tumor surgery, especially glioma surgery, has the most evidence for the use of iMRI contributing more than 50% of all iMRI publications, with increased rates of gross total resection in both adults and children, providing a potential survival benefit. Across multiple neurosurgical disciplines, the ability to use a multitude of unique sequences (diffusion tract imaging, diffusion-weighted imaging, magnetic resonance angiography, blood oxygenation level-dependent) allows for specialization of imaging for various types of surgery. Generally, iMRI allows for consideration of anatomic changes and real-time feedback on surgical outcomes such as extent of resection and instrument (screw, lead, electrode) placement. However, implementation of iMRI is limited by cost and feasibility, including the need for installation, shielding, and compatible tools. Evidence for iMRI use varies greatly by specialty, with the most evidence for tumor, vascular, and pediatric neurosurgery. The benefits of real-time anatomic imaging, a lack of radiation, and evaluation of surgical outcomes are limited by the cost and difficulty of iMRI integration. Nonetheless, the ability to ensure patients are provided by a maximal yet safe treatment that specifically accounts for their own anatomy and highlights why iMRI is a valuable and underutilized tool across multiple neurosurgical subspecialties.

Management and Outcome of Recurring Low-Grade Intramedullary Astrocytomas

Intramedullary astrocytomas (IMAs) are the second most frequent intramedullary tumors in adults. Low-grade IMAs (LG-IMA, WHO grade I and II) carry a better prognosis than high-grade IMAs (HG-IMAs). However, adjuvant treatment of LG-IMAs by radiotherapy (RT) and/or chemotherapy (CT) as well as treatment of tumor recurrences remains controversial. The aim of our study was to evaluate the postoperative outcome of LG-IMAs and the management of recurring tumors. We retrospectively reviewed a series of patients operated on for IMA from 1980 to 2022 in a single neurosurgical department. We retrieved 40 patients who received surgery for intramedullary astrocytomas, including 30 LG-IMAs (22 WHO grade I; 5 WHO grade II; 3 "low-grade") and 10 HG-IMAs (4 WHO grade III; 5 WHO grade IV; 1 "high-grade"). Of the patients with LG-IMAs, the extent of surgical resection was large (gross or subtotal resection >90%) in 30% of cases. Immediate postoperative radiotherapy and/or chemotherapy was proposed only to patients who underwent biopsy (n = 5), while others were initially followed-up. Over a median follow-up of 59 months (range = 13-376), 16 LG-IMA (53.3%) recurred with a mean delay of 28.5 months after surgery (range = 3-288). These included seven biopsies, five partial resections (PR), four subtotal resections (STR) but no gross total resections (GTR). Progression-free survival for LG-IMAs was 51.9% at 3 years and 35.6% at 5 and 10 years; overall survival was 96.3% at 3 years; 90.9% at 5 years and 81.9% at 10 years. There were no significant differences in terms of OS and PFS between WHO grade I and grade II tumors. However, "large resections" (GTR or STR), as opposed to "limited resections" (PR and biopsies), were associated with both better OS (p = 0.14) and PFS (p = 0.04). The treatment of recurrences consisted of surgery alone (n = 3), surgery with RT and/or CT (n = 2), RT with CT (n = 3), RT alone (n = 2) or CT alone (n = 2). In conclusion, although LG-IMAs are infiltrating tumors, the extent of resection (GTR or STR), but not WHO grading, is the main prognostic factor. The management of recurring tumors is highly variable with no conclusive evidence for either option.

Predictors for spinal deformity following resection of intramedullary tumor via posterior approach: a systematic review and meta-analysis

PURPOSE

The present study aimed to identify the clinical predictive factors for worsened spinal deformity (SD) following surgical resection via posterior approach for primary intramedullary tumors.

METHODS

A systematic search was performed using PubMed, Web of Science, and Scopus databases to extract potential references. Observational studies reporting predictive factors for worsened SD following surgical resection via posterior approach for primary intramedullary tumors were included. The odds ratio (OR) was calculated for dichotomous parameters.

RESULTS

Four retrospective cohort studies were included in the meta-analysis. They were comprised of two groups of patients; those who developed SD (n = 87) and those who did not (n = 227). For patients with IMSCTs, age under 25 years as well as age under 13 years were the demographic variables associated with postoperative SD (odds ratio [OR] 3.92; p = 0.0002 and OR 4.22; p = 0.003). In both the fusion and the non-fusion subgroups, preoperative spinal deformity strongly predicted postoperative SD (OR 11.94; p < 0.001), with the risk highly elevated among the non-fusion patients (OR 24.64; p < 0.0002). Thoracolumbar junction involvement was also found to be a predictor of postoperative SD for patients with IMSCT (OR 2.89; p = 0.02).

CONCLUSION

This study highlights the importance of considering age, preoperative spinal deformity, and thoracolumbar junction involvement as predictors of postoperative spinal deformity following surgical resection for IMSCT. These findings may provide guidance for the management of these patients, including the development of preoperative planning strategies and the selection of the most appropriate surgical approach for high-risk patients.

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.

Case report: Surgical treatment of an astrocytoma in the thoracic spinal cord of a cat

A 15-year-old spayed female domestic shorthaired cat was evaluated for chronic progressive paraparesis and proprioceptive ataxia. Neurological examination was consistent with a T3-L3 myelopathy. Plain thoracolumbar vertebral column radiographs and CT without intravenous contrast or myelography performed at another facility did not highlight any abnormalities. MRI of the thoracolumbar spinal cord identified an intraparenchymal space-occupying lesion extending from T10-T12. Surgery was performed to remove as much of the mass as possible, and to submit samples for histopathology. A dorsal laminectomy was performed over T9-T13. A midline myelotomy provided access to the mass, which was debrided with an intraoperative estimate of 80% removal. Histopathologic examination was consistent with a diagnosis of an astrocytoma. Post-operative treatment consisted of amoxicillin clavulanic acid, prednisolone, gabapentin, and additional analgesic medications in the direct post-operative period. Over the following 4 months, slow recovery of motor function was seen with continued physiotherapy. During the following 2 months, renal and cardiopulmonary disease were diagnosed and treated by other veterinarians. The cat was also reported to have lost voluntary movement in the pelvic limbs during this period, suggesting regression to paraplegia. Finally, 6 months post-surgery, the owner elected humane euthanasia. This is the second documentation of surgical treatment and outcome of an astrocytoma in the spinal cord of a cat.

Outcomes of Intramedullary Spinal Cord Tumor Surgery in Older Versus Younger Adults: A Multicenter Subanalysis Study by the Neurospinal Society of Japan

OBJECTIVE

Intramedullary spinal cord tumors (IMSCTs) are uncommon and difficult to treat. Studies examining the efficacy of rare IMSCT surgery in the elderly are limited. We conducted a subanalysis using multicenter retrospective-historical data provided by the Japan Neurospinal Society to compare surgical outcomes between older and younger adults with IMSCTs.

METHODS

We classified patients with IMSCTs into younger (aged 18-64 years) or older ( ≥ 65 years) groups. The primary outcomes of "improved" or "worsened" from the preoperative period to 6 months after surgery were evaluated using the modified McCormick scale (mMCs). A favorable outcome was defined as an mMCs grade of I/II at 6 months.

RESULTS

Among 841 patients registered, there were 658 younger (78.2%) and 183 older patients (21.8%) evaluated using mMCs at 6 months. Median preoperative mMCs grades were significantly worse in older patients than in younger patients. Neither the "improved" nor "worsened" rate differed significantly between the groups (28.1% vs. 25.1%; crude odds ratio [cOR], 0.86; 95% confidence interval [CI], 0.59-1.25; adjusted OR [aOR], 0.84; 95% CI, 0.55-1.28; 16.9% vs. 23.0%; cOR, 1.47; 95% CI, 0.98-2.20; aOR, 1.28; 95% CI, 0.83-1.97). Favorable outcomes were significantly less common among older adults in the univariate analysis but were not significant in the multivariate analysis (66.4% vs. 53.0%; cOR, 0.57; 95% CI, 0.41-0.80; aOR, 0.77; 95% CI, 0.50-1.19). In both younger and older patients, preoperative mMCs accurately predicted favorable outcomes.

CONCLUSION

Age alone is not a sufficient reason to prohibit surgery for IMSCTs.

Malignant Spinal Tumors

Malignant spinal tumors constitute around 22% of all primary spinal tumors. The most common location of metastases to the spinal region is the extradural compartment. The molecular and genetic characterization of these tumors was the basis for the updated WHO classification of CNS tumors in 2016, where many CNS tumors are now diagnosed according to their genetic profile rather than relying solely on the histopathological appearance. Magnetic resonance imaging (MRI) is the current gold standard for the initial evaluation and subsequent follow-up on intradural spinal cord tumors, and the imaging sequences must include T2-weighted images (WI), short time inversion recovery (STIR), and pre- and post-contrast T1-WI in the axial, sagittal, and coronal planes. The clinical presentation is highly variable and depends on the tumor size, growth rate, type, infiltrative, necrotic and hemorrhagic potential as well as the exact location within the spinal compartment. Surgical intervention remains the mainstay of management of symptomatic and radiographically enlarging spinal tumors, where the goal is to achieve maximal safe resection. Tumor recurrences are managed with repeat surgical resection (preferred whenever possible and safe), radiotherapy, chemotherapy, or any combination of these therapies.

Current Trends in the Surgical Management of Intramedullary Tumors: A Multicenter Study of 1,033 Patients by the Neurospinal Society of Japan

OBJECTIVE

We performed a retrospective observational study to demonstrate the surgical risks and long-term prognoses of intramedullary tumors in Japan using a multicenter registry authorized by the Neurospinal Society of Japan.

METHODS

Data from 1,033 consecutive patients with intramedullary tumors, treated between 2009 and 2020, were collected from 58 centers. Patients with spinal lipomas or myxopapillary ependymomas were excluded. Patient characteristics, clinical presentations, imaging characteristics, treatments, and outcomes were analyzed. The modified McCormick scale was used to classify functional status. Survival was described using Kaplan-Meier curves, and multivariable logistic regression analyses were performed.

RESULTS

The mean age of the patients was 48.4 years. Data of 361 ependymomas, 196 hemangioblastomas, 168 astrocytic tumors, 160 cavernous malformations, and the remaining 126 cases including subependymomas, metastases, schwannomas, capillary hemangiomas, and intravascular B-cell lymphomas were analyzed. Twenty-two patients were undiagnosed. The mean follow-up duration was 46.1 ± 38.5 months. Gross total tumor removal was achieved in 672 tumors (65.1%). On the modified McCormick scale, 234 patients (22.7%) had worse postoperative grades at the time of discharge. However, neurological status gradually improved. At 6 months postoperatively, 251 (27.5%), 500 (54.9%), and 160 patients (17.6%) had improved, unchanged, and worsened grades, respectively. Preoperative functional status, gross total tumor removal, and histopathological type were significantly associated with mortality and functional outcomes.

CONCLUSION

Our findings demonstrate better postoperative functional outcomes in patients with fewer preoperative neurological deficits. Degree of resection, postoperative treatments, and prognoses are closely related to the histology of intramedullary tumors.

Revisiting role of Intra-operative ultrasound in Spine surgery for extradural pathologies. Review and clinical usage

OBJECTIVES

This case series looks at the role of intra-operative ultrasound in spine surgery for extradural pathologies METHODS: 10 cases of different pathologies were included. Following posterior laminectomy, intra-operative ultrasound was used to determine the adequacy of decompression. The surgical approach and the extent of surgery was then determined based on ultrasound observations. Post-operative MRI was done to correlate the ultrasound findings RESULTS: We found intra-operative ultrasound to be a very useful, easy to use and interpret tool in spine surgery. The adequacy of decompression was well visualized. The finding also corelated with the decompression achieved on a post-surgery MRI scan.

CONCLUSIONS

Intra-operative ultrasound is a useful tool in routine spine surgery. It is effective, easy to read to determine decompression for various pathologies including disc herniation, epidural abscess, tumors and deformity and reconstructive surgeries. This simple tool can help plan surgeries.

Spinal hemangioblastomas: analysis of surgical outcome and prognostic factors

The prognostic factors for surgically removed spinal hemangioblastomas, the impact of VHL disease on outcome, and the role of intraoperative neuromonitoring are still not completely clear. The aim of this study was to review our experience with spinal hemangioblastomas in order to assess potential predictors of neurological outcome after surgery. All cases of spinal hemangioblastomas removed at two Italian academic institutions from 1985 to 2020 were reviewed. Data about clinical presentation and symptom duration, diagnosis of VHL, surgical approach, use of IONM, duration of hospital stay, follow-up, and modified McCormick grade before and after surgery were extracted. Sixty-one patients (31 F, 30 M) underwent 69 surgeries to remove 74 spinal hemangioblastomas (37 cervical, 32 thoracic, 5 lumbar). Improvement was found in 32.3% of cases, neurological condition remained stable in 51.6% of cases, and deteriorated in 16.1% of patients. A worsening trend in VHL patients and an improvement trend in non-VHL patients were detected, despite the lack of statistical significance. Laminotomy and use of IONM were found to be associated with better outcome, although no association was found between surgery without IONM and worse outcome. In most cases, patients affected by spinal hemangioblastomas can expect a good long-term outcome. In our experience, laminotomy seems to be associated with better outcome compared to laminectomy. While its absence is not associated with worse outcome, IONM seems to be associated with a better neurological outcome. Our study suggests that the more impaired the preoperative neurological condition, the worse the outcome.

Recurrence of cervical intramedullary gliofibroma

INTRODUCTION

Gliofibroma is a rare tumor that develops in the brain and spinal cord. Due to the rarity of its nature, its pathophysiology and appropriate treatment remain elusive. We report a case of intramedullary spinal cord gliofibroma that was surgically treated multiple times. This report is of great significance because this is the first case of recurrence of this tumor.

CASE PRESENTATION

A 32-year-old woman complained of gait disturbance and was referred to our institution. At the age of 13 years, she was diagnosed with intramedullary gliofibroma and underwent gross total resection (GTR) in another hospital. Based on imaging findings, tumor recurrence was suspected at the level of cervical spinal cord, and surgery was performed. However, the resection volume was limited to 50% because the boundary between the tumor and spinal cord tissue was unclear and intraoperative neuromonitoring alerted paralysis. At 1 year postoperatively, the second surgery was performed to try to resect the residual tumor, but subtotal resection was achieved at most. At 2 years after the final surgery, no tumor recurrence was observed, and neurologic function was maintained to gait with cane.

DISCUSSION

Although complete resection is desirable for this rare tumor at the initial surgery, there is a possibility to recur even after GTR with long-term follow-up. During surgical treatment for tumor recurrence, fair adhesion to the spinal cord is expected, and reoperation and/or adjuvant therapy might be considered in the future if the tumor regrows and triggers neurological deterioration.

Variability in the distance from the end of the gray matter to the end of the conus medullaris: a case-triggered histological investigation

OBJECTIVE

The background for this investigation was the dramatic course of a 14-year-old girl with a spontaneous hemorrhage in the area of the conus medullaris resulting in a complete cross-sectional syndrome with bladder and bowel dysfunction. Despite immediate surgical treatment, the patient showed close to no postoperative improvement. Subsequent histopathological examination of the removed masses revealed a cavernoma. To better understand the link between the site and symptoms of conus medullaris lesions, the authors performed a literature search and then histological examination of the conus medullaris of 18 cadaveric specimens from body donors.

METHODS

After a literature search regarding the histological features of the structure of the conus medullaris did not lead to satisfying results, the authors performed histological examination of the conus medullaris in 18 cadaveric specimens from body donors. The largest (a) and smallest (b) diameters of the conus medullaris were measured, noting individual variations in the distance from the caudal ending of the gray matter to the macroscopically visible end of the conus medullaris. Correlations of these differences with sex, body height, gray matter transverse diameter, and cross-sectional area at the end of the gray matter were analyzed.

RESULTS

Gray matter displayed in the form of a butterfly figure was found along almost the entire length of the conus medullaris. The specific slide containing the end of the gray matter was noted. The distance between the caudal ending of the gray matter in the conus and the macroscopical end of the conus medullaris was defined as the gray matter to cone termination (GMCT) distance. There were great individual variations in the distance from the caudal ending of the gray matter to the macroscopically visible end of the conus medullaris. Analysis of the correlations of these differences with sex, body height, gray matter transverse diameter, and cross-sectional area at the end of the gray matter showed no significant sex-specific differences in the GMCT distance. Patient body height and transverse diameter at the end of the gray matter were found to be correlated positively with the GMCT distance. Moreover, greater height also correlated positively with the cross-sectional area at the end of the gray matter.

CONCLUSIONS

This report is, to the authors' knowledge, the first published description of the histological structure of the conus medullaris and can serve as the basis for a better understanding of neurological deficits in patients with a conus medullaris syndrome. Findings that gray matter can be detected far into the conus medullaris, with large individual differences in the endpoint of the gray matter, are important for operative care of intramedullary masses and vascular malformations in this area. It is therefore important to use electrophysiological monitoring during these operations.

Enhanced Safety of Pedicle Subtraction Osteotomy Using Intraoperative Ultrasound

BACKGROUND

Pedicle subtraction osteotomy (PSO) can improve sagittal alignment but carries risks, including iatrogenic spinal cord and nerve root injury. Critically, during the reduction phase of the technique, medullary kinking or neural element compression can lead to neurologic deficits.

METHODS

We describe 3 cases of thoracic PSO and evaluate the feasibility, findings, and utility of intraoperative ultrasound in this setting.

RESULTS

Intraoperative ultrasound can provide a visual assessment of spinal cord morphology before and after PSO reduction and influences surgical decision making with regard to the final amount of sagittal plane correction. This modality is particularly useful for confirming ventral decompression of disc-osteophyte complex before reduction and also after reduction maneuvers when there is kinking of the thecal sac but uncertainty about the underlying status of the spinal cord. Intraoperative ultrasound is a reliable modality that fits well into the technical sequence of PSO, adds a minimal amount of operative time, and has few limitations.

CONCLUSIONS

We propose that intraoperative ultrasound is a useful supplement to standard neuromonitoring modalities for ensuring safe PSO reduction and decompression of neural elements.

Refining the treatment of spinal cord lesions: experience from 500 cases

OBJECTIVE

Tumorous lesions of the spinal cord, as well as some vascular lesions like cavernous hemangiomas, demand careful consideration as to the indication and approach for surgery. As these lesions are rare in any departmental series, refinement of treatment strategies evolves over long periods. In this context, the authors evaluated a series of 500 intramedullary lesions for approach, technique, outcome, complications, and follow-up.

METHODS

Five hundred intramedullary lesions in 460 patients were treated with a continuously evolving departmental strategy between 1985 and 2020. No lesions of the cauda equina or filum terminale were included. The focus of the evaluation was on the adaptation of exposure, resective methodology, sequelae, imaging, and rate of recurrence. Thirty-seven patients were children at the time of diagnosis.

RESULTS

Among the 348 neoplastic lesions, the largest subtype was ependymoma (n = 192, 55.2%), followed by astrocytoma (n = 89, 25.6%). As a trend, metastases (n = 21) have become more frequent and more apparent only in the past 15 years. Reoperations for recurrent or progressive cases or referrals after incomplete resection were performed in 56 cases, mostly for progressive diffuse or pilocytic astrocytomas. Among the vascular lesions, 68 (54.8%) were hemangioblastomas, followed by 56 (45.2%) cavernous hemangiomas. All intramedullary tumors were approached through a midline myelotomy, refining an en bloc resection technique for endophytic tumors to increase the rate of radical resection. Cavernous hemangiomas reaching the surface and hemangioblastomas were approached directly. Complete removal was possible in 77.2% of endophytic tumors but in only 41.7% of diffuse tumors. All WHO grade II diffuse astrocytomas, WHO grade III tumors, and glioblastoma progressed despite treatment according to standard regimens. Vascular lesions were regularly removed completely, with only 1 recurrence of a large hemorrhagic thoracic cavernous hemangioma. The major sequelae were sensory deficits and neuropathic pain. Stabilizing instrumentation was placed in 5 cases of spinal deformity, mostly when more than 4 levels were affected, and in the pediatric population.

CONCLUSIONS

In a large series of intramedullary surgeries, refinement of treatment strategies related to exposure, implementation of intraoperative adjuncts such as ultrasound, intraoperative neuromonitoring, resective strategies, and reconstruction were evaluated. The authors found that for almost any defined, endophytic medullary lesion, a safe and complete removal can be offered.

Bevacizumab as a surgery-sparing agent for spinal ependymoma in patients with neurofibromatosis type II: Systematic review and case

Neurofibromatosis type 2 (NF2) is a rare, hereditary tumor syndrome, often requiring repeated surgeries for multiple lesions with significant cumulative morbidity. As such, non-operative management should be considered when possible for this patient population. The aim of this study is to provide a systematic review of the literature regarding this treatment strategy. A descriptive case of a patient in whom bevacizumab treatments enabled over 15 years of surgical postponement for a symptomatic spinal cord ependymoma is also provided. Evidence suggests that bevacizumab is a reasonable surgery-deferring option for cystic lesions, and it may be especially useful in NF2 patients to reduce cumulative morbidity.

A reproduceable in situ xenograft model of spinal glioma

BACKGROUND

Spinal glioma is a nervous system tumor that tends to relapse and has no specific prognostic molecular biomarkers. Thus, a stable and reproduceable animal research model of spinal glioma is urgently needed.

NEW METHOD

We established a new in situ tumor xenograft model of spinal glioma using nude mice. In this study, we implanted tumors into the cervical spinal cord of nude mice to mimic the pathological characteristics of the original tumors.

RESULTS

Through anatomical experiments, we found that the cervical lamina of mice was thinner, the intervertebral space was much wider, and the adhesion muscles were more easily separated. According to the examination of spinal cord sections, the best puncture point we identified was located 0.9 mm lateral to the posterior median line at the level of the line between the midpoints of the scapulae and at a depth of 0.9 mm. In the nude mouse xenograft experiment, the implanted tumor tissue retained the pathological characteristics of the original tumor.

COMPARISON WITH EXISTING METHOD(S)

This model used the cervical spinal cord as the puncture site and patient-derived primary tumor cells, which has never been performed before. Tumor cells could be injected directly without damaging the lamina. Thus, we could reduce the risk of man-made spinal cord injury and infection and avoid destroying the stability and integrity of the spine.

CONCLUSIONS

This study established a stable and reliable animal model of spinal glioma for further molecular research and targeted therapy development.

Stereotactic Radiation for Treating Primary and Metastatic Neoplasms of the Spinal Cord

Stereotactic radiation treatment can be used to treat spinal cord neoplasms in patients with either unresectable lesions or residual disease after surgical resection. While treatment guidelines have been suggested for epidural lesions, the utility of stereotactic radiation for intradural and intramedullary malignancies is still debated. Prior reports have suggested that stereotactic radiation approaches can be used for effective tumor control and symptom management. Treatment-related toxicity has been documented in rare subsets of patients, though the incidences of injury are not directly correlated with higher radiation doses. Further studies are needed to assess the factors that influence the risk of radiation-induced myelopathy when treating spinal cord neoplasms with stereotactic radiation, which can include, but may not be limited to, maximum dose, dose-fractionation, irradiated volume, tumor location, histology and treatment history. This review will discuss evidence for current treatment approaches.

Ten-Segment Intramedullary Ependymoma and Whole Spinal Syringomyelia

BACKGROUND

Ten-segment intramedullary tumors are rare lesions in adults.

CASE DESCRIPTION

In this report, we describe the case of a 30-year-old woman who presented with a 2-year history of right lower limb numbness. Spinal magnetic resonance imaging showed an expansive 10-segment intramedullary lesion and syringomyelia. The final pathologic tests confirmed World Health Organization grade II ependymoma. She received a successful gross total tumorectomy with no obvious surgical-related complications.

CONCLUSIONS

The postoperative recovery is far beyond our expectations.

The role of 5-aminolevulinic acid in spinal tumor surgery: a review

Purpose

Primary intradural spinal neoplasms account for a small proportion of central nervous system tumors. The primary treatment for these tumors consists of maximal safe resection and preservation of neurologic function. Gross total resection, which is associated with the lowest rate of tumor recurrence and longer progression-free survival for most histologies, can be difficult to achieve. Currently, the use of 5-aminolevulinc acid (5-ALA) which takes advantage of Protoporphyrin IX (PpIX) fluorescence, is a well-established technique for improving resection of malignant cerebral gliomas. This technique is being increasingly applied to other cerebral neoplasms, and multiple studies have attempted to evaluate the utility of 5-ALA-aided resection of spinal neoplasms.

Methods

The authors reviewed the existing literature on the use of 5-ALA and PpIX fluorescence as an aid to resection of primary and secondary spinal neoplasms by searching the PUBMED and EMBASE database for records up to March 2018. Data was abstracted from all studies describing spinal neurosurgical uses in the English language.

Results

In the reviewed studies, the most useful fluorescence was observed in meningiomas, ependymomas, drop metastases from cerebral gliomas, and hemangiopericytomas of the spine, which is consistent with applications in cerebral neoplasms.

Conclusions

The available literature is significantly limited by a lack of standardized methods for measurement and quantification of 5-ALA fluorescence. The results of the reviewed studies should guide future development of rational trial protocols for the use of 5-ALA guided resection in spinal neoplasms.

Electronic supplementary material

The online version of this article (10.1007/s11060-018-03080-0) contains supplementary material, which is available to authorized users.

Magnetic Drug Targeting: A Novel Treatment for Intramedullary Spinal Cord Tumors

Most applications of nanotechnology in cancer have focused on systemic delivery of cytotoxic drugs. Systemic delivery relies on accumulation of nanoparticles in a target tissue through enhanced permeability of leaky vasculature and retention effect of poor lymphatic drainage to increase the therapeutic index. Systemic delivery is limited, however, by toxicity and difficulty crossing natural obstructions, like the blood spine barrier. Magnetic drug targeting (MDT) is a new technique to reach tumors of the central nervous system. Here, we describe a novel therapeutic approach for high-grade intramedullary spinal cord tumors using magnetic nanoparticles (MNP). Using biocompatible compounds to form a superparamagnetic carrier and magnetism as a physical stimulus, MNP-conjugated with doxorubicin were successfully localized to a xenografted tumor in a rat model. This study demonstrates proof-of-concept that MDT may provide a novel technique for effective, concentrated delivery of chemotherapeutic agents to intramedullary spinal cord tumors without the toxicity of systemic administration.

Adult pilocytic astrocytoma of conus medullaris: clinical considerations and review of the literature

Astrocytomas are responsible for 30% of all primitive intramedullary tumors with cervicothoracic predominance. However, only about one hundred cases of intramedullary pilocytic astrocytomas were described. The authors described the case of a 69 year-old patient presenting with a broad-base gait, bilateral pain and dysesthesia of inferior limbs with a diagnosis of an intra-axial cystic lesion centered to the conus medullaris, diagnosed as pilocytic astrocytoma of conus medullaris (PACM) after surgery. To the best of our knowledge, only two previous reports concerning PACM were made. As benign lesions associated with long survivals, function should be the mainstay of treatment of PACM. Surgical resection should be performed. Adjuvant radiotherapy or chemotherapy has no establish role in pilocytic astrocytic lesions.

Preoperative steroids do not improve outcomes for intramedullary spinal tumors: a NSQIP analysis of 30-day reoperation and readmission rates

BACKGROUND

Intramedullary spinal cord tumors (IMSCTs) account for 8-10% of all spinal cord tumors and affect patients of all ages. Although uncommon, IMSCTs carry risk of neurological morbidity and mortality, with 5-year survival rates ranging from 50% to 80%. In this study, we utilize the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database to determine the effect of steroid administration on 30-day outcomes following surgery for IMSCTs.

METHODS

ACS-NSQIP data for patients undergoing surgery for intramedullary tumors from 2005 to 2015 was reviewed. Patients were selected based on current procedural terminology (CPT) codes 63285 (Laminectomy, intradural, intramedullary, cervical), 63286 (Laminectomy, intradural, intramedullary, thoracic), and 63287 (Laminectomy, intradural, intramedullary, thoracolumbar). ICD-9 and ICD-10 codes were chosen based on the diagnosis of a tumor. The 30-day clinical outcome data, including reoperations and readmission rates, were collected and compared.

RESULTS

A total of 259 patients were reviewed. One hundred eighty-one patients had benign intramedullary tumors and 78 had malignant intramedullary tumors. The majority of IMSCTs were at the thoracic level (n=100), followed by the cervical (n=99), and thoracolumbar (n=39) levels. Thirty-one patients were on corticosteroid therapy prior to surgery. Patients with preoperative steroid administration had no significant difference in reoperation and readmission rates. No significant differences were noted between steroid vs. non-steroid therapy for discharge destination, length of hospital stay, or other postoperative complications.

CONCLUSIONS

Contrary to previous reports, corticosteroid use prior to surgery for IMSCTs does not have a significant impact on 30-day risk of readmission, reoperation, and risk of postoperative complications.

Use of Intraoperative Ultrasound During Spinal Surgery

STUDY DESIGN

Review and technical report.

OBJECTIVE

Intraoperative ultrasound has been used by spine surgeons since the early 1980s. Since that time, more advanced modes of intraoperative imaging and navigation have become widely available. Although the use of ultrasound during spine surgery has fallen out of favor, it remains the only true real-time imaging modality that allows surgeons to visualize soft tissue anatomy instantly and continuously while operating. It is our objective to demonstrate that for this reason, ultrasound is a useful adjunctive technique for spine surgeons, especially when approaching intradural lesions or when addressing pathology in the ventral spinal canal via a posterior approach.

METHODS

Using PubMed, the existing literature regarding the use of intraoperative ultrasound during spinal surgery was evaluated. Also, surgical case logs were reviewed to identify spinal operations during which intraoperative ultrasound was used. Illustrative cases were selected and reviewed in detail.

RESULTS

This article provides a brief review of the history of intraoperative ultrasound in spine surgery and describes certain surgical scenarios during which this technique might be useful. Several illustrative cases are provided from our own experience.

CONCLUSIONS

Surgeons should consider the use of intraoperative ultrasound when approaching intradural lesions or when addressing pathology ventral to the thecal sac via a posterior approach.

Continuous mapping of the corticospinal tracts in intramedullary spinal cord tumor surgery using an electrified ultrasonic aspirator

Intramedullary spinal cord tumors (IMSCTs) represent a rare entity, accounting for 4%–10% of all central nervous system tumors. Microsurgical resection of IMSCTs is currently considered the primary treatment modality. Intraoperative neurophysiological monitoring (IONM) has been shown to aid in maximizing tumor resection and minimizing neurological morbidity, consequently improving patient outcome. The gold standard for IONM to date is multimodality monitoring, consisting of both somatosensory evoked potentials, as well as muscle-based transcranial electric motor evoked potentials (tcMEPs). Monitoring of tcMEPs is optimal when combining transcranial electrically stimulated muscle tcMEPs with D-wave monitoring. Despite continuous monitoring of these modalities, when classic monitoring techniques are used, there can be an inherent delay in time between actual structural or vascular-based injury to the corticospinal tracts (CSTs) and its revelation. Often, tcMEP stimulation is precluded by the surgeon’s preference that the patient not twitch, especially at the most crucial times during resection. In addition, D-wave monitoring may require a few seconds of averaging until updating, and can be somewhat indiscriminate to laterality. Therefore, a method that will provide immediate information regarding the vulnerability of the CSTs is still needed.

The authors performed a retrospective series review of resection of IMSCTs using the tip of an ultrasonic aspirator for continuous proximity mapping of the motor fibers within the spinal cord, along with classic muscle-based tcMEP and D-wave monitoring.

The authors present their preliminary experience with 6 patients who underwent resection of an IMSCT using the tip of an ultrasonic aspirator for continuous proximity mapping of the motor fibers within the spinal cord, together with classic muscle-based tcMEP and D-wave monitoring. This fusion of technologies can potentially assist in optimizing resection while preserving neurological function in these challenging surgeries.

Pediatric spinal cord astrocytomas: a retrospective study of 348 patients from the SEER database

OBJECTIVE Intramedullary spinal cord tumors comprise 1%-10% of all childhood central nervous system neoplasms, with astrocytomas representing the most common subtype. Due to their rarity and poor prognosis, large population-based studies are needed to assess the epidemiology and survival risk factors associated with these tumors in the hope of improving outcome. The authors undertook this retrospective study to explore factors that may influence survival in pediatric patients with spinal cord astrocytomas. METHODS Utilizing the Surveillance, Epidemiology, and End Results (SEER) database, a prospective cancer registry, the authors retrospectively assessed survival in histologically confirmed, primary spinal cord astrocytomas in patients 21 years of age and younger. Survival was described with Kaplan-Meyer curves, and a multivariate regression analysis was used to assess the association of several variables with survival while controlling for confounding variables. RESULTS This analysis of 348 cases showed that age (hazard ratio [HR] 1.05, 95% CI 1.01-1.09, p = 0.017), nonwhite race (HR 1.74, 95% CI 1.11-2.74, p = 0.014), high-grade tumor status (HR 14.67, 95% CI 6.69-32.14, p < 0.001), distant or invasive extension of the tumor (HR 2.37, 95% CI 1.02-5.49, p = 0.046), and radiation therapy (HR 3.74, 95% CI 2.18-6.41, p < 0.001) were associated with decreased survival. Partial resection (HR 0.37, 95% CI 0.16-0.83, p = 0.017) and gross-total resection (HR 0.39, 95% CI 0.16-0.95, p = 0.039) were associated with improved survival. CONCLUSIONS Younger age appears to be protective, while high-grade tumors have a much worse prognosis. Early diagnosis and access to surgery appears necessary for improving outcomes, while radiation therapy has an unclear role. There is still much to learn about this disease in the hope of curing children with the misfortune of having one of these rare tumors.

Factors affecting functional outcome in patients with intramedullary spinal cord tumors: results from a literature analysis

Recently, great advances have been made in the surgical treatment of intramedullary spinal cord tumors (IMSCTs). Many articles have been published; but looking at the literature of the last 5 years, there are only descriptive reviews and no works in which a literature statistical analysis was performed. Here, we analyzed the literature to identify potential prognosticators of good functional outcome in IMSCT patients. To level out the selected studies, we stratified patients' neurological status as independent (ambulation possible without caregiver assistance) or disabled (cannot ambulate or can only ambulate with caregiver assistance). 18 out of 125 articles were included in the analysis (691 patients). A significant higher percentage of gross total resection (GTR) in ependymomas, hemangioblastomas and cavernomas compared to the astrocytomas (particularly high-grade gliomas) was observed. We found a strong correlation between a good pre-operative neurological function and a good post-operative and at follow-up (FU) neurological status and between GTR and a good post-operative and at FU neurological status. A significant better outcome was found in ependymomas, hemangioblastomas and cavernomas compared to astrocytomas. Our analysis suggests that an early surgery could be reasonable in IMSCTs, because a good pre-operative neurological function is a strong predictor of good neurological outcome. In patients with high-grade gliomas, there is no indication to attempt a GTR due to the infiltrative growth pattern of this tumor that leads to a higher surgical morbidity. Although not innovative, the evidences of our literature statistical analysis strengthen the results from previous surgical series and descriptive reviews.

Review of the History of Non-traumatic Spinal Cord Dysfunction

Background: The incidence of non-traumatic spinal cord dysfunction (SCDys) is reported to be higher than traumatic spinal cord injury (SCI) in many countries. No formal review of the history of SCDys has been published. Objective: This article aims to identify key highlights in the history of SCDys. Method: An electronic literature search was conducted (January 2017) using MEDLINE (1946-2016) and Embase (1974-2016) databases for publications regarding the history of SCDys. Publications on the history of SCI and a selection of neurology textbooks and books on the history of neurology were reviewed for potentially relevant references. The focus of the literature search was on identifying publications that detail key highlights regarding the history of the diagnosis and management of the most common SCDys conditions, as well as those of historical significance. Results: The electronic search of MEDLINE and Embase identified 11 relevant publications. The majority of publications included were identified from the authors' libraries and a selection of books on neurology and the history of neurology. Conclusions: This review outlines the history of SCDys, taking a broader historical perspective and covering the increasing awareness of the role of the spinal cord and knowledge of neuroanatomy. Key milestones in the history of the diagnosis and management of the most common SCDys conditions are presented. An appreciation of the history of SCDys increases our understanding of the large number of people who contributed to our current knowledge of these conditions and in some situations helps guide efforts regarding prevention of SCDys.

Multifocal Intradural Extramedullary Pilocytic Astrocytomas of the Spinal Cord: A Case Report and Review of the Literature

BACKGROUND AND IMPORTANCE: Pilocytic astrocytoma (PA) is among the most common of the central nervous system gliomas in the pediatric population; however, it is uncommon in adults. PAs of the spinal cord in adults are even rarer, with only a few cases found in the literature. We report here the first case in the literature of multifocal intradural extramedullary spinal cord PAs in an adult.

CLINICAL PRESENTATION: Our patient is a 56-yr-old female who presented with loss of balance and an ataxic gait. Multiple extramedullary spinal cord tumors were identified intraoperatively, the lesions completely resected, and all diagnosed as PAs.

CONCLUSION: This case illustrates a unique instance of multifocal intradural extramedullary spinal cord PAs in an adult with no previous history of PA during childhood, no known familial syndromes, and no brain involvement.