It Looks Like a Spinal Cord Tumor but It Is Not

Differentiating neoplastic from non-neoplastic spinal cord pathologies may be challenging due to overlapping clinical and radiological features. Spinal cord tumors, which comprise only 2-4% of central nervous system tumors, are rarer than non-tumoral myelopathies of inflammatory, vascular, or infectious origins. The risk of neurological deterioration and the high rate of false negatives or misdiagnoses associated with spinal cord biopsies require a cautious approach. Facing a spinal cord lesion, prioritizing more common non-surgical myelopathies in differential diagnoses is essential. A comprehensive radiological diagnostic approach is mandatory to identify spinal cord tumor mimics. The diagnostic process involves a multi-step approach: detecting lesions primarily using MRI techniques, precise localization of lesions, assessing lesion signal intensity characteristics, and searching for potentially associated anomalies at spinal cord and cerebral MRI. This review aims to delineate the radiological diagnostic approach for spinal cord lesions that may mimic tumors and briefly highlight the primary pathologies behind these lesions.

Three-Dimensional Volumetric Magnetic Resonance Imaging Analysis of Syringomyelia Evolution After Posterior Fossa Decompression for Chiari Malformation Type1

OBJECTIVE

This study aims to introduce a method of three-dimensional (3D) volume magnetic resonance imaging (MRI) measurements to evaluate the evolution of syringomyelia (SM) in adults with Chiari malformation type 1 (CM-1) after posterior fossa decompression (PFD), to provide reproducible and accurate measurements.

METHODS

Radiologic and clinical data were obtained for 28 patients. MRI 3D syrinx volumes were evaluated by 2 observers using Philips Healthcare Tumor Tracking tool.

RESULTS

The mean SM preoperative volume was 9.1 ± 15.3 cm3 versus 4.6 ± 8.7 cm3 postoperatively, corresponding to a volume variation reduced by -50% ± 33.4%. A total of 21 patients (75%) showed >25% reduction in SM volume postoperatively and 25 patients (89.2%) showed good to excellent postoperative clinical outcomes. Very high interobserver and intraobserver agreement was noted for 3D volumetric analysis with Cohen weighted κ coefficients (0.899-0.991). A negative correlation was found between the number of involved metameres and the postoperative SM volume reduction (Pearson correlation coefficient = 0.378; P = 0.047). Patients with better clinical outcomes had fewer syrinx septae (F = 8.830; P = 0.001). Similarly, better syrinx volume reduction was associated with fewer septae (F = 1.554; P = 0.233). A positive relationship was observed between clinical outcomes and postoperative syrinx volume reduction (F = 1.554; P= 0.233), with data similar to the reported literature.

CONCLUSIONS

This study shows that 3D volume measurement of the syrinx cavity on MRI is a reproducible and accurate method to assess the postoperative evolution of SM in CM-1 after PFD. Most patients (75%) showed a reduction of SM volume, with a mean volume decrease of 50%. The reliability is yet to be validated in further larger studies.

Sacrifice of Involved Nerve Root during Surgical Resection of Foraminal and/or Dumbbell Spinal Neurinomas

Even if usually needed to achieve the gross total resection (GTR) of spinal benign nerve sheath tumors (NSTs), nerve root sacrifice remains controversial regarding the risk of neurological deficit. For foraminal NSTs, we hypothesize that the involved root is poorly functional and thus can be safely sacrificed. All spinal benign NSTs with foraminal extension that underwent surgery from 2013 to 2021 were reviewed. The impacts of preoperative clinical status and patient and tumor characteristics on long-term outcomes were analyzed. Twenty-six patients were included, with a mean follow-up (FU) of 22.4 months. Functional motor roots (C5-T1, L3-S1) were involved in 14 cases. The involved nerve root was routinely sacrificed during surgery and GTR was obtained in 84.6% of cases. In the functional root subgroup, for patients with a pre-existing deficit (n = 5/14), neurological aggravation persisted in one case at last FU (n = 1/5), whereas for those with no preop deficit (n = 9/14), a postoperative deficit persisted in one patient only (n = 1/9). Preoperative radicular pain was the only characteristic significantly associated with an immediate postoperative motor deficit (p = 0.03). The sacrifice of an involved nerve root in foraminal NSTs seems to represent a reasonable and relevant option to resect these tumors, permitting one to achieve tumor resection in an oncologic fashion with a high rate of GTR.

Clipping Test of a Radiculomedullary Artery During Resection of a Dorsal Spinal Meningioma

Arterial supply of the spinal cord is derived from the anterior spinal artery (ASA) and 2 posterior spinal arteries. In the thoracic spine, a few segmental arteries give origins to radiculomedullary arteries (RMAs) that supply the ASA and posterior spinal arteries.¹ In the lower thoracic spine, the supply is provided by the Adamkiewicz artery. Spinal meningiomas may be embedded and/or supplied by the RMA, which may be sacrificed to obtain complete resection. Safety of the thoracic RMA occlusion is controversial,² especially if the Adamkiewicz artery is involved.³ Somatosensory evoked potentials (SSEPs) and motor evoked potentials (MEP) are proposed to detect spinal cord ischemia.⁴ The RMA supplies the anterior spinal cord, and MEPs seem to be more sensitive than SSEPs to test RMA occlusion.² SSEP and MEP monitoring during temporary occlusion has been described and significantly changes at 2 and 7 minutes of occlusion.^5-8 Safe occlusion with unchanged MEPs after 10-minute temporary occlusion of 32 segmental arteries was reported by Salame et al.⁹ We intraoperatively discovered an anterior T10 RMA supplying the adjacent meningioma (Video 1). We temporary clipped the artery for 8 minutes. MEPs were recorded before clipping and every 2 minutes. No changes were observed, and the artery was sacrificed. RMA or segmental artery ligature may be required and is frequently performed in deformity, oncologic, and vascular spine surgery. The clipping test with MEP monitoring is a useful and simple intraoperative tool to identify the critical afferents of the ASA. It doesn't require planification or supplementary materials. Further study might be performed to validate the technique.

Pediatric posterior fossa tumors outcomes: Experience in a tertiary care center in the Middle East

BACKGROUND

Among all childhood cancers, brain tumors are second only to leukemia in incidence and are the most common solid pediatric tumors. More than 60 % of pediatric brain tumors are infra-tentorial. The first-line treatment for most infra-tentorial tumors in pediatric patients is surgical resection, with the goal of gross-total resection, relief of symptoms and hydrocephalus, and increased survival. The proximity to the fourth ventricle, and therefore, the cerebrospinal fluid (CSF) pathways, predisposes children with posterior fossa tumors to the development of obstructive hydrocephalus and multiple other co-morbidities pre and post-surgery.

OBJECTIVES

This study aims to present our series of pediatric posterior fossa tumor surgeries in the Neurosurgical Department at the American University of Beirut Medical Center(AUBMC) and perform internal quality control for our single-institution consecutive series as one of the largest referral and tertiary care centers in the region. The second purpose of this retrospective study is to weigh the risks of surgery against the presumed advantages and to have specific knowledge about the complication rates, especially those related to the CSF pathway, comparing our results to those in the literature.

METHODS

All pediatric patients (< 18 years of age), referred to our center from different regions in the middle east, and surgically treated for a posterior fossa tumor from June 2006 to June 2018 at the American University of Beirut Medical Center were included. A thorough review of all medical charts was performed to validate all the database records.

RESULTS

The patient sample consisted of 64 patients having a mean age of 6.19 ± 4.42 years and 59.37 % of whom were males. The most common tumor pathology was pilocytic astrocytoma (40.62 %) followed by medulloblastoma (35.93 %) and ependymoma. The most common type of tumor that was seen in patients that developed mutism postoperatively (n = 6, 9.37 %) was medulloblastoma (n = 4, 66.66 %). In this patient sample, 12.28 % (n = 7) of the patients developed hydrocephalus postoperatively.Midline tumors were more associated with the development of mutism(OR = 4.632, p = 0.306) and hydrocephalus (OR = 5.056, p = 0.135) postoperatively, albeit not statistically significantly.The presence of a preoperative shunt was shown to be protective against the development of CSF leak (OR = 0.636, p = 0.767), as none of the patients that came in with CSF diversion developed a CSF leak after their surgery.

CONCLUSION

This study from a single center experience accompanied by a thorough literature review sheds light on the complications frequently encountered after posterior fossa tumor surgery in children. These included transient cerebellar mutism, CSF leak, and hydrocephalus as seen in some of our patients. Our findings highlight the need for prospective studies with well-defined protocols directed at assessing novel ways and approaches to minimize the risk of these complications.

Craniocervical Rosai-Dorfman Disease Involving the Vertebral Artery: Case Report and Literature Review

BACKGROUND

Rosai-Dorfman disease (RDD), also known as sinus histiocytosis with massive lymphadenopathy, is a rare non-Langerhans cell reactive histiocytic disorder that rarely occurs in the central nervous system (CNS). Extranodal RDD most frequently involves the skin, upper respiratory tract, soft tissue, gastrointestinal tracts, bones, breast, and CNS.

CASE DESCRIPTION

RDD of the CNS infiltrates most commonly the dura of the sella, cavernous sinus, and the periclival regions. It is usually clinically and radiologically mistaken for meningioma because of its focal dural-based aspect. RDD is confirmed histologically by lymphoplasmacytic cells and histiocytes of varying size showing emperipolesis (lymphocytophagocytosis). To date, only 4 cases of RDD displaying spinal cord compression secondary to craniocervical junction involvement have been reported.

CONCLUSION

We report the case of a patient diagnosed with RDD localized at the foramen magnum extending to the base of the odontoid process and involving the V4 segment vertebral artery.

Spinal sarcomas and immunity: An undervalued relationship

Sarcomas, especially spine sarcomas, are rare yet debilitating and are underestimated types of cancer. Treatment options for spine sarcomas are limited to chemotherapy, radiotherapy and surgical intervention. Accumulating evidence suggests a complex course associated with the treatment of spine sarcomas as compared to other soft tissue sarcomas in the extremities since adjuvant therapy adds limited success to the oncological outcome. Likewise, the limitations of surgical interventions imposed by the proximity and high sensitivity of the spinal cord, leads to an increased recurrence and mortality rates associated with spine sarcomas. Finding novel treatment options to spine sarcomas as such is inevitable, necessitating a more thorough understanding of the different mechanisms of the underlying etiologies of these tumors. In this review, we discuss the most recent studies tackling the involvement of the immune system; a key player in the emergence of the different types of spine sarcomas and the promising immune-mediated targeted therapy that can be applied in these kind of rare cancers.