Intradural Spinal Tumors—Review of Postoperative Outcomes Comparing Intramedullary and Extramedullary Tumors from a Single Institution's Experience

Single-Center Experience of Resection of 120 Cases of Intradural Spinal Tumors

BACKGROUND

Our study presents a single-center experience of resection of intradural spinal tumors either with or without using intraoperative computed tomography-based registration and microscope-based augmented reality (AR). Microscope-based AR was recently described for improved orientation in the operative field in spine surgery, using superimposed images of segmented structures of interest in a two-dimensional or three-dimensional mode.

METHODS

All patients who underwent surgery for resection of intradural spinal tumors at our department were retrospectively included in the study. Clinical outcomes in terms of postoperative neurologic deficits and complications were evaluated, as well as neuroradiologic outcomes for tumor remnants and recurrence.

RESULTS

112 patients (57 female, 55 male; median age 55.8 ± 17.8 years) who underwent 120 surgeries for resection of intradural spinal tumors with the use of intraoperative neuromonitoring were included in the study, with a median follow-up of 39 ± 34.4 months. Nine patients died during the follow-up for reasons unrelated to surgery. The most common tumors were meningioma (n = 41), schwannoma (n = 37), myopapillary ependymomas (n = 12), ependymomas (n = 10), and others (20). Tumors were in the thoracic spine (n = 46), lumbar spine (n = 39), cervical spine (n = 32), lumbosacral spine (n = 1), thoracic and lumbar spine (n = 1), and 1 tumor in the cervical, thoracic, and lumbar spine. Four biopsies were performed, 10 partial resections, 13 subtotal resections, and 93 gross total resections. Laminectomy was the common approach. In 79 cases, patients experienced neurologic deficits before surgery, with ataxia and paraparesis as the most common ones. After surgery, 67 patients were unchanged, 49 improved and 4 worsened. Operative time, extent of resection, clinical outcome, and complication rate did not differ between the AR and non-AR groups. However, the use of AR improved orientation in the operative field by identification of important neurovascular structures.

CONCLUSIONS

High rates of gross total resection with favorable neurologic outcomes in most patients as well as low recurrence rates with comparable complication rates were noted in our single-center experience. AR improved intraoperative orientation and increased surgeons' comfort by enabling early identification of important anatomic structures; however, clinical and radiologic outcomes did not differ, when AR was not used.

Bilateral epidural D-wave monitoring during resection of an eccentric cervical astrocytoma with evidence of asymmetrical corticospinal desynchronization

BACKGROUND AND IMPORTANCE

The surgical management of intramedullary spinal cord tumours (IMSCT) poses inherent risk to neurologic function. Direct-wave (D-wave) monitoring is routinely reported to be a robust prognostic measure of spinal cord function via midline recording within the epidural or intradural space in a cranial-caudal montage. We explored the feasibility of bilateral epidural D-wave monitoring with routine evoked potentials in promoting safe and maximal resection in a patient with diminished midline D-wave baselines associated with an eccentric intramedullary cervical astrocytoma.

CLINICAL PRESENTATION

We describe the presentation, surgical management, electrophysiological findings and post-operative outcome of a 46 year-old female patient who underwent two resections for an eccentric intramedullary cervical astrocytoma. During the first procedure we encountered clinically significant motor evoked potential signal change and discontinuation of resection pending further review. Midline D-wave signals showed no change, however peak amplitude was diminutive (7 uV) and overall morphology was characteristic of corticospinal desynchronization. Post-operatively the patient experienced significant but transient left sided weakness. A subsequent revision procedure incorporating ipsilesional and contralesional D-wave monitoring in addition to routinely incorporated evoked potentials was proposed in order to facilitate a safer resection. The ipsilesional D-wave response was considerably lower in amplitude (2.5 uV) in contrast to the contralesional D-wave (20 uV).

CONCLUSION

To the authors' knowledge this is the first description of bilateral D-wave monitoring as an adjunct to cranial-caudal D-wave montages during IMSCT surgery. In patients with corticospinal desynchronization evidenced by abnormal midline D-wave morphology, bilateral D-wave monitoring in conjunction with routine evoked potentials may be clinically indicated for preservation of motor function and promotion of safe and maximal resection.

Spinal intradural microsurgery in a nascent neurosurgical department: Lessons learned from the first 25 cases

BACKGROUND

Between 2017 and 2021, the newly established Department of Neurosurgery at Shaare Zedek Medical Center in Jerusalem, a high volume metropolitan hospital, operated on 25 intradural lesions in 24 patients (one patient had multiple tumors). In this retrospective study, we review results and lessons learned as experienced surgeons opened a new service line.

METHODS

A multidisciplinary team was assembled and led by experienced neurosurgeons with skills in both microneurosurgery and complex spine care. Standard operative techniques were used. A chart review was done to assess complications and outcome.

RESULTS

25 lesions were reviewed in 24 patients (14 female; 10 male) between the ages of 11-82 years of age. In 14 cases, gross total resection (GTR) was achieved; 11 cases underwent partial resection. Of the 11 non-GTR cases, 3 were initially planned as biopsies. In one case, there was a significant neurologic decline directly related to surgery. In a separate case, there was iatrogenic instability, necessitating further treatment.

CONCLUSIONS

We identify six lessons learned in a nascent neurosurgical department, noting that surgical excellence is of paramount importance, but that the surgeon must also expand his/her role from master technician to team leader. Both microsurgical expertise for neural anatomy and understanding of spinal biomechanics for osseous anatomy is mandatory for surgery of SIDT. This retrospective analysis of our case series demonstrates experienced neurosurgeons can successfully deploy a new service line for challenging cases to the benefit of the hospital and local community.

Constructing 2D maps of human spinal cord activity and isolating the functional midline with high-density microelectrode arrays

Intraoperative neuromonitoring (IONM) is a widely used practice in spine surgery for early detection and minimization of neurological injury. IONM is most commonly conducted by indirectly recording motor and somatosensory evoked potentials from either muscles or the scalp, which requires large-amplitude electrical stimulation and provides limited spatiotemporal information. IONM may inform of inadvertent events during neurosurgery after they occur, but it does not guide safe surgical procedures when the anatomy of the diseased spinal cord is distorted. To overcome these limitations and to increase our understanding of human spinal cord neurophysiology, we applied a microelectrode array with hundreds of channels to the exposed spinal cord during surgery and resolved spatiotemporal dynamics with high definition. We used this method to construct two-dimensional maps of responsive channels and define with submillimeter precision the electrophysiological midline of the spinal cord. The high sensitivity of our microelectrode array allowed us to record both epidural and subdural responses at stimulation currents that are well below those used clinically and to resolve postoperative evoked potentials when IONM could not. Together, these advances highlight the potential of our microelectrode arrays to capture previously unexplored spinal cord neural activity and its spatiotemporal dynamics at high resolution, offering better electrophysiological markers that can transform IONM.

Evaluation of Surgically Treated Primary Spinal Cord Tumors in a Single Brazilian Institution: A Case Series Study of 104 Patients

Background: Primary spinal cord tumors are rare and heterogeneous, and their prevalence varies among the studies. Few articles have evaluated the prevalence, characteristics, and histological types of spinal cord tumors in Latin American populations. This study aimed to analyze the histological types and clinical aspects of a series of consecutive patients diagnosed with primary spinal cord tumors who underwent surgical treatment in a single Brazilian institution and to compare them with the literature.

Methods: This is a case series study, with retrospective analysis of all consecutive adult patients who underwent surgical treatment for primary spinal cord tumors in a single center between January 1997 and April 2021. Data analyzed included age at surgery, sex, anatomical location, histopathological diagnosis, clinical presentation, and neurological status at discharge.

Results: A total of 104 patients (53 women [51.0%]; mean age, 49.0 ± 16.7 years [range, 19-87 years]) were included in the analysis. Among the tumors, 83.7% were benign, and 36.5% involved the thoracic spine; intradural extramedullary lesions comprised 52.9% of the tumors, and the most prevalent were schwannomas (26.9%) and meningiomas (18.3%). Among the patients, 55% and 50% presented with pain and motor deficit, respectively, and the deficit improvement rate was greater than the worsening rate at the immediate postoperative period and discharge.

Conclusions: Our series highlights the heterogeneity of primary spinal cord tumors compared to other studies. Further large population studies are necessary to elucidate the epidemiology of this disease.

Nerve root magnetic stimulation improves locomotor function following spinal cord injury with electrophysiological improvements and cortical synaptic reconstruction

Following a spinal cord injury, there are usually a number of neural pathways that remain intact in the spinal cord. These residual nerve fibers are important, as they could be used to reconstruct the neural circuits that enable motor function. Our group previously designed a novel magnetic stimulation protocol, targeting the motor cortex and the spinal nerve roots, that led to significant improvements in locomotor function in patients with a chronic incomplete spinal cord injury. Here, we investigated how nerve root magnetic stimulation contributes to improved locomotor function using a rat model of spinal cord injury. Rats underwent surgery to clamp the spinal cord at T10; three days later, the rats were treated with repetitive magnetic stimulation (5 Hz, 25 pulses/train, 20 pulse trains) targeting the nerve roots at the L5–L6 vertebrae. The treatment was repeated five times a week over a period of three weeks. We found that the nerve root magnetic stimulation improved the locomotor function and enhanced nerve conduction in the injured spinal cord. In addition, the nerve root magnetic stimulation promoted the recovery of synaptic ultrastructure in the sensorimotor cortex. Overall, the results suggest that nerve root magnetic stimulation may be an effective, noninvasive method for mobilizing the residual spinal cord pathways to promote the recovery of locomotor function.

Multiple Spinal Syphilitic Gummas Diagnosed by Postoperative Histopathology and Antibiotic Responsiveness: A Case Report

Neurosyphilis is an infection of the central nervous system by Treponema pallidum. Gummatous neurosyphilis, especially spinal syphilitic gumma, is an exceedingly rare manifestation and may be misdiagnosed as other tumors due to its rarity. A 42-year-old man with a medical history of treatment for syphilis presented with rapidly progressive leg paralysis, leg sensory disturbance, and bladder and rectal disturbance. Spinal MRI demonstrated an intradural extramedullary lesion strongly compressing the spinal cord at the T6/7 level, which was accompanied with dural tail sign and perilesional meningeal thickening at the T6–T8 levels. Small intradural extramedullary lesions were also detected at the T1 and T8 levels. Serological and cerebrospinal fluid examinations for syphilis were both positive. In the treatment of spinal syphilitic gumma, the decompression of the spinal cord by lesionectomy followed by postoperative antibiotic treatment is considered to be an optimal procedure in patients with rapid progression of neurological deterioration. In the present case, the symptomatic main lesion that was compressing the thoracic cord was excised by surgery and analyzed by histopathological examination, and another small asymptomatic lesion was resolved by postoperative antibiotic treatment. Spinal syphilitic gumma was diagnosed using both histopathological findings of the surgically resected lesion and another residual lesion that was resolved by postoperative antibiotic treatment.

Agreement and differentiation of intradural spinal cord lesions in dogs using magnetic resonance imaging

Background

Magnetic resonance imaging is the method of choice for diagnosing spinal cord neoplasia, but the accuracy of designating the relationship of a neoplasm to the meninges and agreement among observers is unknown.

Objectives

To determine agreement among observers and accuracy of diagnosis compared with histology when diagnosing lesion location based on relationship to the meninges.

Animals

Magnetic resonance images from 53 dogs with intradural extramedullary and intramedullary spinal neoplasms and 17 dogs with degenerative myelopathy.

Methods

Six observers were supplied with 2 sets of 35 images at different time points and asked to designate lesion location. Agreement in each set was analyzed using kappa (κ) statistics. We tabulated total correct allocations and calculated sensitivity, specificity, and likelihood ratios for location designation from images compared with known histologic location for lesions confined to 1 location only.

Results

Agreement in the first set of images was moderate (κ = 0.51; 95% confidence interval [CI], 0.43‐0.58) and in the second, substantial (κ = 0.69; 95% CI, 0.66‐0.79). In the accuracy study, 180 (75%) of the 240 diagnostic calls were correct. Sensitivity and specificity were moderate to high for all compartments, except poor sensitivity was found for intradural extramedullary lesions. Positive likelihood ratios were high for intradural extramedullary lesions and degenerative myelopathy.

Conclusions and Clinical Importance

Overall accuracy in diagnosis was reasonable, and positive diagnostic calls for intradural extramedullary lesions and negative calls for intramedullary lesions are likely to be helpful. Observers exhibited considerable disagreement in designation of lesions relationship to the meninges.

Tumor Occupancy Ratio-An Imaging Characteristic Prognosticating the Surgical Outcome of Benign Intradural Extramedullary Spinal Cord Tumors

BACKGROUND

Intradural extramedullary (IDEM) spinal cord tumors are two thirds of all spinal tumors. We have prospectively analyzed the importance of the tumor occupancy ratio as a factor for predicting the course of the disease and in prognosticating the surgical outcome in patients with IDEM tumors.

METHODS

We prospectively analyzed 44 consecutive cases of IDEM tumors, diagnosed as cervical, thoracic, and lumbar IDEM tumors (excluding conus/cauda equina lesion) by magnetic resonance imaging (MRI), that were operated on at our institution between 2014 and 2016. We measured the tumor occupancy ratio and noted the sagittal and axial location of the tumor in the preoperative MRI and performed the laminectomy and unilateral medial facetectomy. A primary outcome has been noted according to the gait disability score in the preoperative period and in the follow-up period of 1 year. In the statistical analysis, categorical variables were compared using a chi-square test, and an analysis of variance and student t tests were used for the continuous variables. P < .05 was considered statistically significant.

RESULTS

The tumor occupancy ratio showed a significant association to the preoperative gait disability score (P < .001) and also predicted that the surgical outcome is much better in patients with tumors with a low tumor occupancy ratio than in patients with tumors with a high occupancy ratio (P < .001). No difference in the tumor occupancy ratio was noted in 2 different pathological tumors, and there was also no difference in the tumor occupancy ratio at different sagittal and axial locations of the tumor.

CONCLUSION

Tumor occupancy ratio has shown a significant impact on the preoperative course and also predicts the surgical outcome in patients with IDEM tumors. Hence, it is an important imaging characteristic to prognosticate the outcome in IDEM tumors and should be noted in each case.

Surgical treatment and outcomes of intramedullary tumors by minimally invasive approach

Intramedullary tumors are uncommon neoplasms which, without treatment, can cause neurologic morbidity or mortality. The goal of the treatment is complete surgical resection with a minimally invasive approach while preserving neurological status and also spinal stability. Out of 1972 patients with tumors of the spinal canal treated between 1994 and 2017, 168 intramedullary tumors of 417 intradural tumors have been presented. All patients had undergone one surgical resection. The mean age is 43 ± 12 years (range 11-67 years). Tumors were subdivided into 4 groups: cervically located-tumors (n = 43), cervicothoracic-region-tumors (n = 32), thoracic-region-tumors (n = 57), and lumbosacral-region-tumors (n = 36). The mean follow-up time was 37 ± 29 months. Gross-total resection rate was higher in cervical located intramedullary tumors compared to the thoracic intramedullary tumors. Cervical intramedullary tumors showed better postoperative functional outcome than the thoracic intramedullary lesions. In intramedullary tumors, extending more than 3 spinal segments, postoperative worsening was significantly increased. A minimally invasive approach (the bilateral decompression via unilateral hemilaminectomy) was used to remove the tumor while preserving spinal stability. Perioperative permanent morbidity was very low. Intramedullary tumors should be surgically treated as soon as neurological symptoms appear. Patients with thoracic intramedullary tumors and tumor extension of more than three segments were at a higher risk for permanent morbidity. The minimally invasive approach allowed complete removal of the intramedullary tumors, and adequate preservation of vertebral stability while providing a good postoperative course.

Postoperative Venous Thromboembolism in Extramedullary Spinal Tumors

Context:

Venous thromboembolism (VTE), including deep-vein thrombosis (DVT) and pulmonary embolism (PE), is the fatal complication following spine surgery and the appropriate perioperative prophylaxis is still debated.

Aims:

The aim of this study is to evaluate the incidence of along with risk factors for postoperative VTE in surgically treated extramedullary spinal tumor patients.

Setting and Designs:

The study design involves single institute and retrospective cohort study.

Subjects and Methods:

The cohort database was reviewed between the periods of January 2014 and June 2019. Patients undergoing surgery for spine tumor, extradural tumor, and intradural extramedullary were consecutively collected.

Statistical Analysis Used:

The incidence of VTE and clinical factors reported to be associated with VTE were identified, and then analyzed with an appropriate Cox regression model.

Results:

The study identified 103 extramedullary spinal tumor patients. Three patients (2.9%) were diagnosed with a proximal leg DVT, while symptomatic PE did not identify. Risk factors associated with DVT occurrence were as follows: operative time ≥8 h (Hazard ratio [HR] 13.98, P = 0.03) and plasma transfusion (HR 16.38, P = 0.02), whereas plasma transfusion was the only significant factor, after multivariate analysis (HR 11.77, P = 0.05).

Conclusions:

Patients who underwent surgery for extramedullary spinal tumors showed a 2.9% incidence of DVT. The highest rate of DVT was found in patients who received plasma transfusion. More attention should be paid on perioperative associated factors for intensive prevention coupled with early screening in this group.

Diagnostic and therapeutic values of intraoperative electrophysiological neuromonitoring during resection of intradural extramedullary spinal tumors: a single-center retrospective cohort and meta-analysis

OBJECTIVE

With the advent of intraoperative electrophysiological neuromonitoring (IONM), surgical outcomes of various neurosurgical pathologies, such as brain tumors and spinal deformities, have improved. However, its diagnostic and therapeutic value in resecting intradural extramedullary (ID-EM) spinal tumors has not been well documented in the literature. The objective of this study was to summarize the clinical results of IONM in patients with ID-EM spinal tumors.

METHODS

A retrospective patient database review identified 103 patients with ID-EM spinal tumors who underwent tumor resection with IONM (motor evoked potentials, somatosensory evoked potentials, and free-running electromyography) from January 2010 to December 2015. Patients were classified as those without any new neurological deficits at the 6-month follow-up (group A; n = 86) and those with new deficits (group B; n = 17). Baseline characteristics, clinical outcomes, and IONM findings were collected and statistically analyzed. In addition, a meta-analysis in compliance with the PRISMA guidelines was performed to estimate the overall pooled diagnostic accuracy of IONM in ID-EM spinal tumor resection.

RESULTS

No intergroup differences were discovered between the groups regarding baseline characteristics and operative data. In multivariate analysis, significant IONM changes (p < 0.001) and tumor location (thoracic vs others, p = 0.018) were associated with new neurological deficits at the 6-month follow-up. In predicting these changes, IONM yielded a sensitivity of 82.4% (14/17), specificity of 90.7% (78/86), positive predictive value (PPV) of 63.6% (14/22), negative predictive value (NPV) of 96.3% (78/81), and area under the curve (AUC) of 0.893. The diagnostic value slightly decreased in patients with schwannomas (AUC = 0.875) and thoracic tumors (AUC = 0.842). Among 81 patients who did not demonstrate significant IONM changes at the end of surgery, 19 patients (23.5%) exhibited temporary intraoperative exacerbation of IONM signals, which were recovered by interruption of surgical maneuvers; none of these patients developed new neurological deficits postoperatively. Including the present study, 5 articles encompassing 323 patients were eligible for this meta-analysis, and the overall pooled diagnostic value of IONM was a sensitivity of 77.9%, a specificity of 91.1%, PPV of 56.7%, and NPV of 95.7%.

CONCLUSIONS

IONM for the resection of ID-EM spinal tumors is a reasonable modality to predict new postoperative neurological deficits at the 6-month follow-up. Future prospective studies are warranted to further elucidate its diagnostic and therapeutic utility.