The Clinical Outcomes of Cervical Spine Chordoma: A Nationwide Multicenter Retrospective Study.

OBJECTIVE: Chordoma, a rare malignant tumor originating from embryonal notochord remnants, exhibits high resistance to conventional treatments, making surgical resection imperative. However, the factors influencing prognosis specifically for cervical spine chordoma have not been clearly identified. We investigate the prognosis of cervical spine chordoma with factors influential in a nationwide multicenter retrospective study. METHODS: This study included all patients diagnosed with cervical spine chordoma at 7 tertiary referral centers from January 1998 to March 2023, excluding those with clivus and thoracic spine chordomas extending into the cervical spine. Local recurrence (LR) was identified through follow-up magnetic resonance imaging, either as reappearance in completely resected tumors or regrowth in residual tumors. The study assessed LR and overall survival, analyzing factors influencing LR and death. RESULTS: Forty-five patients with cervical spine chordoma had a mean age of 46.4 years. Over a median follow-up of 52 months, LR and distant metastasis were observed in 21 (46.7%) and 4 patients (8.9%), respectively, and 16 patients (36%) were confirmed dead. The 5-year and 10-year cumulative LR rates were 51.3% and 60%, respectively, while the 5-year and 10-year survival rates were 82% and 53%. Age was the only significant factor affecting mortality (hazard ratio, 1.04; 95% confidence interval, 1.04-1.07; p=0.015). Notably, the degree of resection and adjuvant therapy did not statistically significantly impact local tumor control and mortality. CONCLUSION: This study, the largest multicenter retrospective analysis of cervical spine chordoma in Korea, identified age as the only factor significantly affecting patient survival.

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

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

Revisiting En Bloc Resection Versus Piecemeal Resection for the Treatment of Giant Cell Tumor of the Spine.

OBJECTIVE: Surgery for spinal giant cell tumors (GCTs) is challenging because these tumors often exhibit a poor clinical course owing to their locally aggressive features. This study aimed to investigate the prognostic factors of GCT recurrence in the spine by focusing on surgical factors. METHODS: We retrospectively reviewed patients who underwent surgery for spinal GCTs between January 2005 and December 2016. Using the Kaplan-Meier method, surgical variables were evaluated for disease-free survival (DFS). Since tumor violation may occur at the pedicle during en bloc resection of the spine, it was further analyzed as a separate variable. Multivariate Cox proportional hazard regression analysis was performed for other clinical and radiographic variables. A total of 28 patients (male:female = 8:20) were included. The mean follow-up period was 90.5 months (range, 15-184 months). RESULTS: Among the 28 patients, gross total resection (GTR) was the most important factor for DFS (P = 0.001). Any form of tumor violation was also correlated with DFS (P = 0.049); however, use of en bloc resection technique did not show a significant DFS gain compared to piecemeal resection (P = 0.218). In the patient group that achieved GTR, the mode of resection was not a significant factor for DFS (P = 0.959). In the multivariate analysis, the extent of resection was the only significant variable that affected DFS (P = 0.016). CONCLUSIONS: Conflicting results on tumor violation from univariate and multivariate analyses suggest that GTR without tumor violation should be the treatment goal for spinal GCTs. However, when tumor violation is unavoidable, it would be important to prioritize GTR over adhering to en bloc resection.

Impact on Spine Surgery during the First Two Years of COVID-19 Pandemic: A Nationwide Study in South Korea.

Since December 2019, the novel coronavirus (COVID-19) has infected people worldwide. Owing to its rapid spread, elective surgeries, including spine surgery, have been re-scheduled. We analyzed nationwide data to investigate changes in the volume of spine surgery during the first two years of the pandemic. Nationwide data from January 2016 to December 2021 were obtained. We compared the total number of patients who underwent spine surgery and related medical expenses before and during the COVID-19 pandemic. In February and September, the number of patients was significantly smaller compared to January and August, respectively. Despite the pandemic, the proportion of patients undergoing spine surgery for degenerative diseases in 2021 was the highest. In contrast, the proportions of patients undergoing spine surgery for tumors showed a continuous decrease from 2019 to 2021. Although the number of spine surgeries performed at tertiary hospitals was lowest in 2020, it was not significantly smaller than that in 2019.The number of patients who underwent spine surgery in March 2020, during the first outbreak, decreased compared to the previous month, which differed from the trend observed in the pre-COVID-19 period. However, as the pandemic continues, the impact of COVID-19 on spine surgery has become less evident.

Long-term Follow-up Results of Reconstructive Laminoplasty With L-shaped Leibinger Mini-plate for Posterior Approach in the Treatment of Intraspinal Tumor Surgery.

OBJECTIVE: Laminoplasty using mini-plates is one of the most common surgical techniques in surgery for intraspinal pathologies. However, limited are present in the literature. The aim of this study was to determine its long-term clinical and radiologic outcome, specifically using an L-shaped mini-plate. METHODS: Patients who underwent surgery for spinal intradural pathology from January 2008 to December 2019 were retrospectively reviewed. Those who received laminoplasty using the Leibinger mini-plate and were followed for more than 2 years were included. Patient demographics and clinical and radiographic data were reviewed and analyzed. A total of 117 patients (male:female = 47:70; mean age 50.9 years, range 16-92 years) were included, and mean follow-up period was 50.3 months (range 24-151 months). RESULTS: The most common pathology was schwannoma (n = 66, 56.4%) followed by meningioma (n = 30, 25.6%). Gross total resection was achieved in 82.9% (n = 97). Clinical outcomes at last follow-up were mostly good and excellent (n = 95, 81.2%). Computed tomography at the postoperative 1-year follow-up were available in 32 patients (27.4%) and the overall fusion rate was 89.3% (50 of 56 laminae). The fusion rate was significantly lower in the cervical spine compared to other locations (50% vs. thoracic [100%], lumbar [85.7%], P < 0.002). No displacement of laminae or postoperative spinal deformity were observed throughout the follow-up. CONCLUSIONS: Laminoplasty using L-shape Leibinger mini-plates had an 89.3% fusion rate, and no displacement of the re-attached laminae was observed. We think it is a safe and feasible option in surgeries for intraspinal pathologies.

Dural rupture and subsequent spinal cord herniation due to closed wound suction drainage after spinal surgery.

Closed wound suction drains are commonly used in spinal surgery. Severe neurological complications related to their use are rare. Here, we report a case of a dural rupture and subsequent spinal cord herniation related to the use of closed suction drains after posterior decompression and fixation surgery for spinal metastasis.

Clinical and dosimetric risk factors for vertebral compression fracture after single-fraction stereotactic body radiation therapy for spine metastases.

OBJECTIVES: This analysis was performed to evaluate the incidence of vertebral compression fracture (VCF) and determine the contributing factors for VCF in patients undergoing single-fraction stereotactic body radiotherapy (SBRT) for spinal bone metastases (SBM). METHODS: A retrospective review of medical records was conducted for patients undergoing SBRT for SBM at our institution between January 2010 and December 2018. Patients who had undergone neither pre-SBRT surgical excision nor post-SBRT prophylactic fixation were included. The effects of clinical and dosimetric parameters were analyzed with respect to VCF risk. The following dosimietric parameters of the planning target volume (PTV) were calculated: mean/minimum/maximum dose, radiation dose to 10-90% volume, and irradiated volume receiving more than 10-25 Gy (PTV_V10 - 25 Gy). RESULTS: Among 163 patients (179 vertebrae), 21 (12.8%) experienced VCF. The 1-year and 2-year VCF rates were 12.1% and 13.2%, respectively. Among dosimetric parameters, PTV_V15 Gy was the most significant for VCF prediction. In a univariate analysis, breast or prostate primary, no vertebral body collapse, and PTV_V15 Gy ≤42 cm3 were significantly associated with a lower incidence rate of VCF. In a multivariate analysis, PTV_V15 Gy was the only significant factor for VCF risk. The 1-year VCF rate was 3.8% in patients with PTV_V15 Gy ≤42 cm3, while it was 22.1% in those with PTV_V15 Gy > 42 cm3 (p < 0.01). CONCLUSIONS: SBRT-related VCF was found in 12% of patients in our institution. The PTV_V15 Gy is a significant factor for VCF prediction.

Nonsurgical treatment outcomes for surgical candidates with lumbar disc herniation: a comprehensive cohort study.

Physicians often encounter surgical candidates with lumbar disc herniation (LDH) who request non-surgical management even though surgery is recommended. However, second opinions may differ among doctors. Therefore, a prospective comprehensive cohort study (CCS) was designed to assess outcomes of nonsurgical treatment for surgical candidates who were recommended to undergo surgery for LDH but requested a second opinion. The CCS includes both randomized and observational cohorts, comprising a nonsurgery cohort and surgery cohort, in a parallel fashion. Crossover between the nonsurgery and surgery cohorts was allowed at any time. The present study was an as-treated interim analysis of 128 cases (nonsurgery cohort, n = 71; surgery cohort, n = 57). Patient-reported outcomes included visual analogue scores for the back (VAS-B) and leg (VAS-L), the Oswestry Disability Index, the EuroQol 5-Dimension instrument, and the 36-Item Short-Form Health Survey (SF-36), which were evaluated at baseline and at 1, 3, 6, 12, and 24 months. At baseline, age and SF-36 physical function were significantly lower in the surgery cohort than in the nonsurgery cohort (p < 0.05). All adjusted outcomes significantly improved after both nonsurgical and surgical treatment (p < 0.05). The nonsurgery cohort showed less improvement of VAS-B and VAS-L scores at 1 month (p < 0.01), but no difference between cohorts was observed thereafter for 24 months (p > 0.01). Nonsurgical management may be a negotiable option even for surgical candidates in the shared decision-making process.

Radiologic Efficacy and Patient Satisfaction after Minimally Invasive Unilateral Laminotomy and Bilateral Decompression in Patients with Lumbar Spinal Stenosis: A Retrospective Analysis.

BACKGROUND AND STUDY AIMS: Lumbar spinal stenosis (LSS) is the most common spinal disease in older adults. Although surgical modalities are recommended in patients who are unresponsive to conservative treatment, the most appropriate minimally invasive surgical procedure for patients with LSS remains controversial. Moreover, few previous studies have focused on patient-centered outcomes with radiologic correlation. In the present study, we aimed to investigate radiologic efficacy and patient satisfaction following bilateral decompression via unilateral laminotomy. MATERIALS AND METHODS: We performed a retrospective analysis of radiologic efficacy and patient satisfaction in a series of surgical patients treated at our institution. We classified patients into two groups based on the primary pathology (i.e., central or lateral recess stenosis). Medical records were analyzed retrospectively for radiologic outcomes and clinical parameters including pain and changes in quality of life. Data related to outcomes were collected at 2 weeks, 3 months, and 12 months after surgery in the outpatient clinic. RESULTS: Among the 122 patients enrolled in this study, 51 had central spinal stenosis; 71 had lateral recess stenosis. Radiologically, we observed significant improvements in the anteroposterior diameter and cross-sectional area of the dural sac (central stenosis) and the lateral width of the central canal and depth of the lateral recess (lateral recess stenosis). Two weeks and 12 months after the surgical procedure, we observed significant improvements in the extent of symptoms, patient satisfaction, and quality of life (including physical function). CONCLUSION: Our findings suggest that bilateral decompression via a unilateral approach shows improved radiologic outcomes, varying based on the type of stenosis. Furthermore, patient satisfaction significantly improved regardless of the type of disease.

Differentiating between spinal schwannomas and meningiomas using MRI: A focus on cystic change.

OBJECTIVES: To retrospectively determine the diagnostic ability of MRI in differentiating between intradural extramedullary spinal schwannomas and meningiomas. METHODS: A total of 199 patients with spinal intradural extramedullary tumors who underwent preoperative contrast-enhanced MRI between January 2012 and December 2018 were included in this study. Two radiologists independently analyzed the presence of cystic change, dural tail sign, and neural foraminal extension. Clinical and MRI features between the two groups were compared by univariable and multivariable analyses using logistic regression. Interobserver agreements were calculated using kappa statistics. RESULTS: Patients with schwannoma showed significantly higher frequency of cystic change (96% vs 24%, P < 0.001), neural foraminal extension (29% vs 3%, P = 0.001), and lumbar location (41% vs 5%, P = 0.008). Patients with meningioma showed significantly higher frequency of dural tail sign (64% vs 1%, P < 0.001), thoracic location (75% vs 31%, P = 0.007), older age (59.7 years vs 47.6 years, P < 0.001), higher female predominance (83% vs 50%, P < 0.001), and smaller size (19.8 cm vs 28.8 cm, P < 0.001). Multivariable analysis showed that cystic change (P < 0.001; odds ratio [OR], 0.02), dural tail sign (P < 0.001; OR, 36.23), age (P = 0.032; OR, 1.06), and lumbar location (P = 0.006; OR, 0.02) were independent factors. Interobserver agreements were almost perfect for all analyses. CONCLUSIONS: MRI features were useful in differentiating between intradural extramedullary schwannomas from meningiomas. The presence of cystic change and dural tail sign were independently significant discriminators.

Analysis of postoperative dysphagia after anterior cervical decompression and fusion.

Purpose: To investigate the incidence and risk factors of postoperative dysphagia after anterior cervical decompression and fusion (ACDF) in terms of demographic, procedural and anaesthetic perspectives.Materials and methods: Medical records and radiologic data of patients who underwent anterior cervical surgery performed by two surgeons in a single centre between January 2012 and December 2015 were retrospectively analysed. Patients with spinal tumours, infective spondylitis and traumatic cervical pathologies were excluded. Patients with preoperative dysphagia and previous history of anterior cervical surgery were also excluded. Finally, 127 patients were enrolled. Bazaz dysphagia score was used for the diagnosis of postoperative dysphagia.Results: The incidence of postoperative dysphagia was 10.2% at six weeks after ACDF. Nine patients showed mild dysphagia that fully recovered at three months after ACDF. Four patients showed moderate dysphagia that also recovered fully at six months after surgery. The incidence of postoperative dysphagia increased significantly in cases of C4 or C5 level involvements. Age, sex, hypertension, body mass index, postoperative soft tissue swelling, intubation difficulty and intubation tools were not significant risk factors of ACDF. Diabetes mellitus, two surgical levels, the use of plate, long anaesthetic and operative time and large intubation tube size were causative factors of postoperative dysphagia in multivariable analysis (p < 0.05).Conclusions: The incidence of postoperative dysphagia after ACDF was relatively low, and the prognosis was good.

Architectural Changes in the Medial Gastrocnemius on Sonography after Nerve Ablation in Healthy Adults.

Architectural changes in healthy muscle after denervation have not yet been reported. This study aimed to investigate architectural changes in the medial head of the gastrocnemius muscle (GCM) after aesthetic tibial nerve ablation in healthy adults using ultrasonography (US). The effects of tibial nerve ablation were verified by visual observation and surface electromyography analysis. US images of medial GCMs were taken by one trained physician using B-mode and real-time US with a linear-array probe before nerve ablation, at 1 week after nerve ablation and at 3 months after nerve ablation in an anatomic standing position with the feet about shoulder-width apart in 19 healthy adults (17 females and 2 males). Muscle thickness was significantly reduced on the left side at 1 week and 3 months after the procedure and on the right side at 3 months after the procedure (p<0.050). Although fascicle length was not significantly changed, pennation angle was significantly reduced on both sides at 3 months after the procedure (p<0.050). Muscle thickness and pennation angle of the muscle fascicle were significantly reduced, although fascicle length was not significantly changed, after tibial nerve ablation in the medial GCM of healthy adults.

Paralysis of the gastrocnemius medial head differentially affects gait patterns and muscle activity during level and stair ascent locomotion.

BACKGROUND: Prior studies have analyzed the activity of the gastrocnemius (GCM) medial and lateral heads as a single unit because it is technically challenging to separately analyze the function of each component in vivo. However, functional variation between the medial and lateral heads is expected due to their anatomical differences. RESEARCH QUESTION: What is the independent function of the medial GCM? How does paralysis of the GCM medial head affect gait kinematics?. METHODS: Twelve healthy adults (two males and ten females; age: 28.2 [±7.72] years) that were scheduled to undergo neurolysis of the tibial nerve branch supplying the medial head of the GCM for aesthetic calf reduction participated in the study. Gait analysis was performed using a computerized opto-electric gait analysis system to measure kinematic data. Surface electromyography (EMG) was recorded simultaneously during the gait analysis. Surface electrodes were placed on seven muscles. Pre-procedure and 1-week and 3-month post-procedure data were compared using a linear mixed model. RESULTS: During level walking, decreased activity of the GCM medial head did not significantly change gait kinematics. However, a significant increase in GCM lateral head and hamstring activities occurred after a branch nerve block to the GCM medial head. During stair ascent, in contrast to level walking, changes in EMG activity only occurred in the GCM medial head, and post-procedure ankle dorsiflexion angles at the end of the terminal-stance phase significantly increased. Ankle plantarflexion angles during the push-off phase were also decreased when compared with pre-procedure values. SIGNIFICANCE: The human body response to dysfunction of the GCM medial head depended on the type of locomotion.

Subtotal resection of cervical schwannomas and growth rate of residual tumors.

OBJECTIVEThe objective of this study was to elucidate the features and surgical outcomes of cervical schwannomas.METHODSThe authors retrospectively reviewed the records of 90 patients who underwent surgically treated cervical schwannomas from January 1995 to December 2017, with an emphasis on MRI findings such as tumor location, tumor size, extent of tumor resection, and growth of a residual tumor.RESULTSThis study included 51 men (56.7%) and 39 women (43.3%) with a mean age of 44.5 years (range 7-77 years). Dumbbell-shaped tumors comprised 62 (68.9%) of 90 cases and gross-total resection (GTR) was achieved in 59 (65.6%) of 90 cases. All nondumbbell tumors (n = 28) underwent GTR. Only 1 case of recurrence in the GTR group showed a gradual increase in size (by 8.9 mm) during the 150-month follow-up period. For the regrowth patients in the subtotal resection group, the mean percentage increase in tumor size was 47.5% ± 33.1% and the mean growth rate was 5.8 ± 4.6 mm/year during the 20.3-month follow-up period. However, the size of residual tumor spontaneously decreased by a mean of 8.3% ± 11.1% during the 48.4-month follow-up period in the nonregrowth group.CONCLUSIONSThese findings suggested that frequent MRI follow-up examinations are required for residual schwannomas in the cervical spine for at least 2 years, and continuous MRI follow-ups are also required thereafter.

Subtotal Resection of Cervical Dumbbell Schwannomas: Radiographic Predictors for Surgical Considerations.

OBJECTIVE: Currently, radiologic predictors for the resectability of cervical dumbbell schwannomas remain unknown. To identify radiologic predictors for resectability, we retrospectively reviewed data from 72 patients. METHODS: From January 1995 to June 2017, 72 patients who underwent surgical treatment for cervical dumbbell schwannomas were enrolled. We focused on the relationship between preoperative magnetic resonance imaging (MRI) features and the extent of tumor removal. The MRI features evaluated were tumor size, tumor level, Eden classification, degree of vertebral artery (VA) involvement, and signal intensity (SI) on T2-weighted images (WIs). RESULTS: Among the 72 patients, gross total resection (GTR) and subtotal resection (STR) were achieved in 37 (51.4%) and 35 (48.6%) patients, respectively. Mean maximal tumor size (P = 0.011), mean size of foraminal and extraforaminal portion (P = 0.017), tumor level (P < 0.001), VA involvement (P < 0.001), and SI on T2-WIs (P = 0.006) were significantly different between the GTR and STR groups. Univariate analyses demonstrated that maximal tumor size (odds ratio [OR]: 0.93, P = 0.012), high cervical level (OR: 11.37, P < 0.001), pushed VA (OR: 0.11, P = 0.002), encased VA (OR: 0.02, P < 0.001), and hyper-SI on T2-WIs (OR: 12.46, P = 0.020) were significant predictors for GTR. In the multivariate analysis, only high cervical level (OR: 5.48, P = 0.033) and encased VA (OR: 0.07, P = 0.014) were significant predictors for GTR. CONCLUSIONS: The resectability of cervical dumbbell schwannomas may be predicted by MRI features, including tumor size, tumor level, and degree of VA involvement.

Effects of Zeolite Supports on the Production of Fuel-Range Hydrocarbons in the Hydrotreatment of Various Vegetable Oils with Platinum-Based Catalysts.

The effects of catalyst supports on catalyst performance in the hydrotreatment of vegetable oils (to produce fuel-range hydrocarbons such as gasoline, jet fuel, and diesel) were investigated, using three types of zeolites (ZSM-5, HY, and zeolite-beta (BEA)) that differ in their silica/alumina ratios. Structural characterization of the catalysts was performed using ICP, XRD, BET, TEM, and NH3-TPD. Catalytic tests were carried out in a fixed-bed reaction system at 400 °C and 50 bar. In the hydrotreatment of soybean oil, higher conversions into liquid hydrocarbons and fuel-range hydrocarbons were found when supports with lower Si/Al2 ratios were used. Specifically, Pt/BEA (Si/Al2 = 25) produced the highest conversion into liquid products (72%) and the highest selectivity for hydrocarbons in the jet fuel (46%) and diesel (51%) fuels. A Pt loading amount of 3 wt% in this catalyst gave the best catalytic performance because of the optimal balance between acidic and metallic sites. Finally, the kinds of vegetable oils in the hydrotreatment performance over Pt/BEA (Si/Al2 = 25) affected the order; waste-cooking oil > jatropha oil > soybean oil.

In Vitro Evaluation of Fusiform-Shaped Stents for Wide-Neck Intracranial Aneurysm Treatment.

PURPOSE: Wide-neck aneurysms (WNAs) associated with a dilated parent artery (PA) are not uncommon morphological abnormalities and usually cause inappropriate wall apposition and incomplete neck coverage of a tubular stent in stent-assisted coiling of aneurysms. We aimed to introduce a fusiform-shaped stent (FSS) and test its effectiveness in treating intracranial WNAs associated with a dilated PA using a three-dimensional (3D) model. MATERIALS AND METHODS: Two FSS types were designed with the middle one-third segment dilated by 10% (FSS10) and 20% (FSS20) and were compared with the tubular-shaped stent (TSS). A patient-specific 3D WNA model was prototyped and produced, and in vitro stent placement was performed. Angiographic images of the three stent types were analyzed and compared using predetermined parameters. RESULTS: The stent lumens were significantly larger in FSS10 and FSS20 than in TSS in the middle segments (P=0.046), particularly FSS20 (P=0.018). The non-covered area at the ostium tended to be smaller in FSS10 and FSS20 than in TSS, but the difference was not significant (P>0.05). The stent length was significantly longer in FSS10 and FSS20 than in TSS. The stent cell size was significantly larger in FSS than in TSS. CONCLUSION: Better vessel wall apposition and aneurysmal neck coverage was observed for FSS than for TSS. No significant difference was observed between FSS10 and FSS20.

Analysis of Multimodal Intraoperative Monitoring During Intramedullary Spinal Ependymoma Surgery.

OBJECTIVE: To evaluate the validity of intraoperative somatosensory-evoked potential (SSEP) and motor-evoked potential (MEP) monitoring according to 2 different warning criteria during 6 months from intramedullary spinal ependymoma surgery. METHODS: Twenty-six patients who underwent intramedullary spinal ependymoma surgery with intraoperative monitoring from January 2010 to June 2017 were retrospectively analyzed. We examined the sensitivity, specificity, positive predictable value, negative predictable value, and diagnostic odds ratio of SSEP and MEP monitoring for each extremity according to 2 warning criteria: 50% decline and all-or-none. The postoperative motor deficit was evaluated using the Medical Research Council scale. The postoperative neurologic deficit was followed up during 6 months. RESULTS: Eighty-six extremities were evaluated. The success rates of SSEP and MEP monitoring were 84.9% and 83.7%, respectively. Indeterminate cases were 1 in SSEP and 6 in MEP. All-or-none criterion in SSEP and MEP monitoring showed greater specificity, positive predictable value, and diagnostic odds ratio than 50% decline criterion during 6 months. The validity of SSEP was high in the upper extremity, whereas that of MEP was high in the lower extremity. During the follow-up, 37 of 38 extremities (97.4%) and 18 of 29 extremities (62.1%) showed improvement in sensory and motor deficit, respectively. Seven indeterminate cases also showed good clinical outcomes. CONCLUSIONS: Many false-positive and false-negative results of SSEP and MEP monitoring occurred during the immediate postoperative period. All-or-none criterion was more beneficial for assessing postoperative neurologic status than 50% decline criterion. This trend was maintained until 6 months after surgery.

The Impact of Surgical Treatment on Survival in Patients With Cervical Spine Metastases.

OBJECTIVE: To compare overall survival (OS) in patients with cervical spine metastases between initial radiotherapy followed by surgery and initial surgery followed by radiotherapy. METHODS: The medical records of 36 patients with cervical spine metastases from January 2007 to December 2015 were retrospectively analyzed. These patients were divided into 2 groups. Group 1 included patients who underwent initial radiotherapy followed by surgery, while group 2 included patients who underwent initial surgery followed by radiotherapy. Clinical outcomes, OS, OS after cervical spine metastasis, and OS after surgery were analyzed in both groups. We evaluated whether primary tumor type, initial treatment modality, the modified Tomita score, Eastern Cooperative Oncology Group performance status, Karnofsky performance status, Japanese Orthopedic Association (JOA) score, Nurick grade, Frankel classification, and preoperative symptoms were associated with OS after cervical spine metastasis. RESULTS: Both groups exhibited improvement in the postoperative visual analogue scale, but only group 2 showed a significant improvement in postoperative JOA score (p=0.03). OS did not differ significantly between groups. However, OS after cervical spine metastasis was only 7.0 months (95% confidence interval [CI], 4.8-9.3) in group 1 versus 15.8 months (95% CI, 8.8-24.0) in group 2, which represented a significant difference (p<0.05). Factors related to OS after cervical spine metastasis were primary tumor type, initial treatment modality, and preoperative symptoms (p<0.05). Patients who presented with only preoperative pain had approximately 3 fold longer OS after cervical spine metastasis than patients with preoperative motor weakness, even in group 2 (p<0.05). CONCLUSION: Surgical treatment prior to the onset of motor weakness or radiotherapy may be a good decision in case of cervical spine metastasis.

Predicting Survival of Patients with Spinal Ependymoma Using Machine Learning Algorithms with the SEER Database.

OBJECTIVE: This study was conducted to understand the clinical and demographic factors influencing the overall survival (OS) of patients with spinal ependymoma and to predict the OS with machine learning (ML) algorithms. METHODS: We compiled spinal ependymoma cases diagnosed between 1973 and 2014 from the Surveillance, Epidemiology, and End Results (SEER) registry. To identify the factors influencing survival, statistical analyses were performed using the Kaplan-Meier method and Cox proportional hazards regression model. In addition, we implemented ML algorithms to predict the OS of patients with spinal ependymoma. RESULTS: In the multivariate analysis model, age ≥65 years, histologic subtype, extraneural metastasis, multiple lesions, surgery, radiation therapy, and gross total resection (GTR) were found to be independent predictors for OS. Our ML model achieved an area under the receiver operating characteristic curve (AUC) of 0.74 (95% confidence interval [CI], 0.72-0.75) for predicting a 5-year OS of spinal ependymoma and an AUC of 0.81 (95% CI, 0.80-0.83) for predicting a 10-year OS. The stepwise logistic regression model showed poorer performance by an AUC of 0.71 (95% CI, 0.70-0.72) for predicting a 5-year OS and an AUC of 0.75 (95% CI, 0.73-0.77) for predicting a 10-year OS. CONCLUSIONS: With SEER data, we reaffirmed that therapeutic factors, such as surgery and GTR, were associated with improved OS. Compared with statistical methods, ML techniques showed satisfactory results in predicting OS; however, the dataset was heterogeneous and complex with numerous missing values.