Study Design: Broad narrative review. Objectives: Intramedullary spinal cord tumors (IMSCT) are rare neoplasms that can potentially lead to severe neurologic deterioration, decreased function, poor quality of life, or death. As such, a better understanding of these lesions is needed. The following article, part one of a two-part series, addresses IMSCT with regards to their epidemiology, histology, pathophysiology, imaging characteristics, and clinical manifestations. Methods: The authors performed an extensive review of the peer-reviewed literature addressing the aforementioned objectives. Results: Numerous IMSCT exist with varying epidemiology. Each IMSCT has its own hallmark characteristics and may vary with regards to how aggressively they invade the spinal cord. These lesions are often difficult to detect and are often misdiagnosed. Furthermore, radiographically and clinically, these lesions may be difficult to distinguish from one another. Conclusions: Awareness and understanding of IMSCT is imperative to facilitate an early diagnosis and plan management.

OBJECT: Patients with symptomatic intradural-extramedullary (ID-EM) tumors may be successfully treated with resection of the lesion and decompression of associated neural structures. Studies of patients undergoing open resection of these tumors have reported high rates of gross-total resection (GTR) with minimal long-term neurological deficit. Case reports and small case series have suggested that these patients may be successfully treated with minimally invasive surgery (MIS). These studies have been limited by small patient populations. Moreover, there are no studies directly comparing perioperative outcomes between patients treated with open resection and MIS. The objective of this study was to compare perioperative outcomes in patients with ID-EM tumors treated using open resection or MIS. METHODS: A retrospective review was performed using data collected from 45 consecutive patients treated by open resection or MIS for ID-EM spine tumors. These patients were treated over a 9-year period between April 2003 and October 2012 at Northwestern University and the University of Chicago. Statistical analysis was performed to compare perioperative outcomes between the two groups. RESULTS: Of the 45 patients in the study, 27 were treated with the MIS approach and 18 were treated with the open approach. Operative time was similar between the two groups: 256.3 minutes in the MIS group versus 241.1 minutes in the open group (p = 0.55). Estimated blood loss was significantly lower in the MIS group (133.7 ml) compared with the open group (558.8 ml) (p < 0.01). A GTR was achieved in 94.4% of the open cases and 92.6% of the MIS cases (p = 0.81). The mean hospital stay was significantly shorter in the MIS group (3.9 days) compared with the open group (6.1 days) (p < 0.01). There was no significant difference between the complication rates (p = 0.32) and reoperation rates (p = 0.33) between the two groups. Multivariate analysis demonstrated an increased rate of complications in cervical spine tumors (OR 15, p = 0.05). CONCLUSIONS: Thoracolumbar ID-EM tumors may be safely and effectively treated with either the open approach or an MIS approach, with an equivalent rate of GTR, perioperative complication rate, and operative time. Patients treated with an MIS approach may benefit from a decrease in operative blood loss and shorter hospital stays.

OBJECTIVE: The primary objective of this study was to evaluate the safety of 3 escalating doses of oligodendrocyte progenitor cells (LCTOPC1; previously known as GRNOPC1 and AST-OPC1) administered at a single time point between 21 and 42 days postinjury to participants with subacute cervical spinal cord injuries (SCIs). The secondary objective was to evaluate changes in neurological function following administration of LCTOPC1. METHODS: This study was designed as an open-label, dose-escalation, multicenter clinical trial. Twenty-five participants with C4–7 American Spinal Injury Association Impairment Scale grade A or B injuries received a single dose of either 2 × 10⁶, 1 × 10⁷, or 2 × 10⁷ LCTOPC1 delivered via intraparenchymal injection into the spinal cord at the site of injury using a custom-designed syringe positioning device. Low-dose tacrolimus was administered until day 60. Outcome measures included adverse event (AE) monitoring and neurological function as measured by the International Standards for Neurological Classification of Spinal Cord Injury. RESULTS: All 25 participants experienced at least one AE, with a total of 534 AEs (32 study-related vs 502 study-unrelated anticipated complications of SCI) reported at the completion of 1-year follow-up. There were 29 serious AEs reported. Two grade 3 serious AEs (CSF leak in one participant and a bacterial infection in another) were considered related to the injection procedure and to immunosuppression with tacrolimus, respectively. The CSF leakage resolved with sequelae, including self-limited altered mental status, and the infection resolved with antibiotic therapy. For all participants, MRI scans demonstrated no evidence of an enlarging mass, spinal cord damage related to the injection procedure, inflammatory lesions in the spinal cord, or masses in the ventricular system. At 1-year follow-up, 21/22 (96%) of the intention-to-treat group recovered one or more levels of neurological function on at least one side of their body, and 7/22 (32%) recovered two or more levels of neurological function on at least one side of their body. CONCLUSIONS: LCTOPC1 can be safely administered to participants in the subacute period after cervical SCI. The injection procedure, low-dose temporary immunosuppression regimen, and LCTOPC1 were well tolerated. The safety and neurological function data support further investigation to determine the efficacy of LCTOPC1 in the treatment of SCI. Clinical trial registration no.: NCT02302157 (ClinicalTrials.gov)

OBJECT: Back pain is an increasing concern for the aging population. This study aims to evaluate if minimally invasive surgery presents cost-minimization benefits compared with open surgery in treating adult degenerative scoliosis. METHODS: Seventy-one patients with adult degenerative scoliosis received 2-stage, multilevel surgical correction through either a minimally invasive spine surgery (MIS) approach with posterior instrumentation (n = 38) or an open midline (Open) approach (n = 33). Costs were derived from hospital and rehabilitation charges. Length of stay, blood loss, and radiographic outcomes were obtained from electronic medical records. Functional outcomes were measured with Oswestry Disability Index (ODI) and visual analog scale (VAS) surveys. RESULTS: Patients in both cohorts were similar in age (Age_MIS = 65.68 yrs, Age_Open = 63.58 yrs, p = 0.28). The mean follow-up was 18.16 months and 21.82 months for the MIS and Open cohorts, respectively (p = 0.34). MIS and Open cohorts had an average of 4.37 and 7.61 levels of fusion, respectively (p < 0.01). Total inpatient charges were lower for the MIS cohort ($269,807 vs $391,889, p < 0.01), and outpatient rehabilitation charges were similar ($41,072 vs $49,272, p = 0.48). MIS patients experienced reduced length of hospital stay (7.03 days vs 14.88 days, p < 0.01) and estimated blood loss (EBL) (EBL_MIS = 470.26 ml, EBL_Open= 2872.73 ml, p < 0.01). Baseline ODI scores were lower in the MIS cohort (40.03 vs 48.04, p = 0.03), and the cohorts experienced similar 1-year improvement (ΔODI_MIS = −15.98, ΔODI_Open = −21.96, p = 0.25). Baseline VAS scores were similar (VAS_MIS = 6.56, VAS_Open= 7.10, p = 0.32), but MIS patients experienced less reduction after 1 year (ΔVAS_MIS = −3.36, ΔVAS_Open = −4.73, p = 0.04). Preoperative sagittal vertical axis (SVA) were comparable (preoperative SVA_MIS = 63.47 mm, preoperative SVAO_pen = 71.3 mm, p = 0.60), but MIS patients had larger postoperative SVA (postoperative SVA_MIS = 51.17 mm, postoperative SVA_Open = 28.17 mm, p = 0.03). CONCLUSIONS: Minimally invasive surgery demonstrated reduced costs, blood loss, and hospital stays, whereas open surgery exhibited greater improvement in VAS scores, deformity correction, and sagittal balance. Additional studies with more patients and longer follow-up will determine if MIS provides cost-minimization opportunities for treatment of adult degenerative scoliosis.