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Spinal cord injury (SCI) has a significant negative effect on the quality of life due to permanent neurologic damage and economic burden by continuous treatment and rehabilitation. However, determining the correct approach to ensure optimal clinical outcomes can be challenging and remains highly controversial. In particular, with the introduction of the concept of early decompression in brain pathology, the discussion of the timing of decompression in SCI has emerged. In addition to that, the concept of “time is spine” has been added recently, and the mortality and complications caused by SCI have been reduced by providing timely and professional treatment to patients. However, there are many difficulties in establishing international clinical guidelines for the timing of early decompression in SCI because policies for each country and medical institution differ according to the circumstances of medical infrastructure and economic conditions in the surgical treatment of SCI. Therefore, we aim to provide a current review of timing of early decompression in patient with SCI.

The studies interpreting DCI, a complication of SAH, and identifying correlations are very limited. This study aimed to investigate the effect of cilostazol on ACV and DCI after coil embolization for ruptured aneurysms (n = 432). A multivariate analysis was performed and explainable artificial intelligence approaches were used to analyze the contribution of cilostazol as a risk factor on the development of ACV and DCI with respect to global and local interpretation. The cilonimo group was significantly lower than the nimo group in ACV (13.5% vs. 29.3; p = 0.003) and DCI (7.9% vs. 20.7%; p = 0.006), respectively. In a multivariate logistic regression, the odds ratio for DCI for the cilonimo group, female sex, and aneurysm size was 0.556 (95% confidence interval (CI), 0.351–0.879; p = 0.012), 3.713 (95% CI, 1.683–8.191; p = 0.001), and 1.106 (95% CI, 1.008–1.214; p = 0.034). The risk of a DCI occurrence was significantly increased with an aneurysm size greater than 10 mm (max 80%). The mean AUC of the XGBoost and logistic regression models was 0.94 ± 0.03 and 0.95 ± 0.04, respectively. Cilostazol treatment combined with nimodipine could decrease the prevalence of ACV (13.5%) and DCI (7.9%) in patients with aSAH.

Many studies have described different C1-2 fusion techniques that have evolved over time. We introduced an easy and effective C1-2 fusion technique using local bone chips combined with atlantoaxial instrumentation.To identify the efficacy of interfacetal fusion using local bone combined with atlantoaxial instrumentation by assessment of clinical outcomes and fusion rate.We retrospectively reviewed the data from 25 patients who underwent atlantoaxial stabilization surgery using C1-2 pedicle screws and interfacetal bone fusion by a single surgeon between March 2012 and December 2019.The demographics were 15 men and 10 women with a mean age of 57.6 years (range, 27-85 years) at the time of surgery. Three patients underwent surgery for myelopathy due to os odontoideum, 9 for C1-2 instability, 9 for trauma, 3 for rheumatoid arthritis, and 1 for bony spur, C1-2. At 3 months postsurgery, 3 and 21 patients showed 2-point and 1-point improvements in the Nurick grade, respectively. There was no difference in the Nurick score in 1 patient. Seven patients had a computed tomography scan at 1 year after surgery, which revealed a bridging trabecular bone. No movement was observed in the x-ray flexion/extension view at 1 year after surgery in all patients. In addition, no patients complained of postoperative occipital neuralgia.This study showed that interfacetal fusion with C1-2 pedicle screws using the free-hand technique was efficient and simple.

OBJECTIVE Cauda equina tumors affect the peripheral nervous system, and the validities of triggered electromyogram (tEMG) and intraoperative neurophysiologic monitoring (IOM) are unclear. We sought to evaluate the accuracy and relevance of tEMG combined with IOM during cauda equina tumor resection. METHODS Between 2008 and 2018, an experienced surgeon performed cauda equina tumor resections using tEMG at a single institution. A cauda equina tumor was defined as an intradural-extramedullary or intradural-extradural tumor at the level of L2 or lower. The clinical presentation, extent of resection, pathology, recurrence, postoperative neurological outcomes, and intraoperative tEMG mapping and IOM data were retrospectively analyzed. RESULTS One hundred three patients who underwent intraoperative tEMG were included; 38 underwent only tEMG (tEMG-only group), and 65 underwent a combination of tEMG and multimodal IOM (MIOM group). There were no significant differences between the neurologic outcomes, extents of resection, or recurrence rates of the 2 groups. No significant therapeutic benefit was observed; however, the accuracy of intraoperative predetection improved with the combination of IOM and tEMG (accuracy: tEMG-only group, 86.8%; MIOM group, 92.3%). When the involved rootlet was resected despite the positive tEMG result, motor function worsened in 3 of 8 cases. The sensitivity and specificity of tEMG were 37.5% and 94.7%, respectively. CONCLUSION tEMG is an essential adjunctive surgical tool for deciding on and planning for rootlet resection. If the tEMG finding is negative, complete resection, involving the rootlet, may be safe. The accuracy may be further improved by using a combination of tEMG and IOM.

Cerebral hemorrhages require rapid diagnosis and intensive treatment. This study aimed to detect cerebral hemorrhages and their locations in images using a deep learning model applying explainable deep learning. Normal brain images with no hemorrhages and images with subarachnoid, intraventricular, subdural, epidural, and intraparenchymal hemorrhages according to computed tomography (CT) (n = 200) were analyzed. A ResNet deep learning model, including image processing, was utilized. The visual explanation from a heatmap was made at the hemorrhage location using a gradient-class activation map (Grad-CAM). To evaluate the performance of the deep learning system, the accuracy, sensitivity, and specificity were determined. A hemorrhage prediction system for images of normal brains and brains with subarachnoid, intraventricular, subdural, epidural, and intraparenchymal hemorrhages was built. The Grad-CAM representation indicated the location of the hemorrhages in these images. In the prediction results, accurate predictions of the hemorrhage areas were made and visualizations of the corresponding locations overlapped in the images within (− 4, 1) pixel difference. The evaluation of the system performance showed an accuracy of 0.81 with a sensitivity of 0.67 and specificity of 0.86. These results constitue a proof of concept for the use of explainable artificial intelligence (XAI) to detect cerebral hemorrhages and visualize their locations in medical images, which will allow rapid diagnosis and treatment.

STUDY DESIGN Retrospective study. OBJECTIVE The aim of this study was to evaluate the usefulness of computed tomography (CT) attenuation in defining trabecular region-of-interest (t-ROI) at lumbar vertebral body in the assessment of osteoporotic compression fracture (OCF) compared to spinal dual x-ray absorptiometry (DXA). SUMMARY OF BACKGROUND DATA Even though osteoporosis was not diagnosed in the bone mineral density measurement using DXA, we often experienced cases where the screw was weakly inserted due to low bone quality during screw insertion. METHODS A total of 188 patients who met the inclusion criteria were enrolled. We determined best cutoff value of the simple t-ROI attenuation at the most relevant level for predicting OCF. We assessed correlations between the simple t-ROI attenuation at the most relevant level and OCF rate, and investigate the association between the number of compression fracture and simple t-ROI attenuation at the most relevant level. RESULTS L4 ROI attenuation is the most accurate measurement for predicting osteoporotic compression fracture with an area under the curve of 0.798. The optimal cutoff point of L4 ROI attenuation was measured at 90.5 HU with 88.8% and 60.6% sensitivity and specificity, respectively. L4 ROI attenuation was significantly correlated with the osteoporotic compression fracture rate (r = -0.545, P

BACKGROUND C1 pedicle screw insertion is not easy, and more fluoroscopy can be required for safe insertion. Fluoroscopy is time consuming and increases patient radiation exposure. There have been no studies comparing the accuracy of C1 pedicle screw insertion using the fluoroscopy and free-hand techniques. OBJECTIVE To describe a free-hand C1 pedicle screw insertion method in patients with the posterior arch thickness of less than 4 mm in the thinnest part of the groove, and to compare the clinical and radiological outcomes of C1 pedicle screw insertion using fluoroscopy vs using the free-hand technique. METHODS A total of 25 patients who had atlantoaxial instability with a C1 posterior arch

This study aimed to review information on the subaxial cervical pedicle screw (CPS) including recent anatomical considerations, entry points, placement techniques, accuracy, learning curve, and complications. Relevant literatures were reviewed, and the authors' experiences were summarized. The CPS is used for reconstruction of unstable cervical spine and achieves superior biomechanical stability compared to other fixation techniques. Various insertion and guidance techniques are established, among which, lateral fluoroscopy-assisted placement is the most common and cost-effective technique. Generally, placement under imaging guidance is more accurate than other techniques, and a three-dimensional template allows optimal trajectory for each pedicle regardless of intraoperative changes in spinal alignment. The free-hand technique using a curved pedicle probe without a funnel-like hole increases screw stability and reduces operation time, radiation exposure, and soft tissue injury. Compared to conventional lateral fluoroscopy-assisted placement, free-hand CPS placement by trained surgeons achieves superior accuracy comparable to that of image-guided navigation; in general, 30 training cases are sufficient for learning a safe and accurate technique for CPS placement. The complications of subaxial CPS are classified into three categories: complications due to screw misplacement, complications without screw misplacement, and others. Inexperienced surgeons may benefit from advanced techniques; however, the accuracy of CPS ultimately depends on the surgeon's experience. Inexperienced surgeons should master the placement of the thoracolumbar pedicle screw in real practice and practice CPS insertion using cadavers. During the initial phase of the learning curve, careful preparation of surgery, reiterated identification, patterned safety steps, and supervision of the expert are necessary.

Retrospective study.To evaluate the absolute value of L4 trabecular region-of-interest (t-ROI) computed tomography (CT) attenuation, which can predict pedicle screw loosening, and determine the changes in value according to number of fused levels and sagittal balance in patients undergoing lumbar fusion surgery.Although osteoporosis was not diagnosed in spinal dual x-ray absorptiometry preoperatively, we encountered several cases of screw loosening within 1 year of lumbar fusion surgery.We enrolled 478 patients and analyzed factors related to screw loosening. We evaluated the association between L4 t-ROI CT attenuation and screw loosening and determined the best cutoff value of t L4 t-ROI CT attenuation for predicting screw loosening.The number of fused levels, postoperative C7-S1 sagittal vertical axis (SVA), and L4 t-ROI CT attenuation were independently correlated with screw loosening. According to number of fused level and postoperative C7-T1 SVA (≥36.9 mm or36.9 mm), in patients with one-level fusion and C7-S1 SVA less than 36.9 mm, the optimal cutoff point of the L4 t-ROI CT attenuation predicting screw loosening was 106.5 Hounsfield unit (HU). L4 t-ROI attenuation did not change until two-level fusions. In patients with three-level fusions and C7-S1 SVA less than 36.9 mm, the optimal cutoff point of the L4 t-ROI CT attenuation predicting screw loosening was 159.0 HU. The optimal cutoff point of L4 t-ROI CT attenuation in patients with three-level fusions and C7-S1 SVA more than or equal to 36.9 mm was 191.0 HU.L4 t-ROI CT attenuation value considering number of fused levels and sagittal balance is an accurate measurement method to predict screw loosening. Spine surgeons should be aware of the L4 t-ROI attenuation before surgery to improve the fusion rate and reduce instrument-related complications of lumbar spine surgery in osteoporotic patients.3.

Background: In malalignment syndrome, the spino-pelvic alignment correction with foot orthotics can be applied only to a standing position in the coronal plane. Considering the fact that the average time Koreans spend sitting in a chair is 7.5 hours per day, studies on spino-pelvic correction in sitting position is needed. The purpose of this study is to investigate the pressure changes and radiographic assessment of spino-pelvic alignment using a chair equipped with a height-adjustable seat-plate.Methods: Experiments were conducted on 30 research participants. The inclusion criteria for the participants were as follows: The volunteers of nonstructural malignment syndrome with shoulder height differences (SHDs) or iliac flea height differences (ICHDs) greater than 5 mm in radiographic images excluding participants with structural deformity. All participants were subjected to measure buttocks interface pressure while seated using a smart chair in three consecutive steps: (1) on initial seated, (2) on balancing seated, and then (3) on 1hr balancing seated. Radiographically, the five spino-pelvic parameters such as SHD, ICHD, LLD, POA, and coronal imbalance were analyzed to investigate the effect of pelvic imbalance compensation on spino-pelvic alignment.Results: Pelvic imbalance was compensated with seat plate height adjustment in average of 3.6 ± 1.8 mm, so that the pressure discrepancy improvement between buttocks from 36.4 ± 32.3 on initial seated to 15.7 ± 20.3 on balancing, 12.7 ± 10.9 on 1hr balancing seated (Ω, p=0.008). The radiographic changes before and after pelvic imbalance compensation demonstrated a statistically significant improvements of spino-pelvic parameters on sitting and standing: at the average value of -0.9 to -0.8 and 9.5 to 2.5, SHD and ICHD, respectively (mm, p=0.005, 0.037) and -3.0 to -1.0, 1.8 to 0.8, and 0.8 to 0.1, SHD, ICHD, and LLD, respectively (mm, p=0.005, 0.016, 0.033).Conclusions: Spino-pelvic malalignment can be improved by individually customized pelvic compensation using balanced seat plate height adjustments under the real-time pressure sensing and monitoring on the buttocks while seated.

Objective: Studies have reported several treatment modalities for patients with lumbosacral radicular pain. However, the available evidence is not robust to establish definitive conclusions. The goal of this study was to evaluate the clinical efficacy of pulsed radiofrequency (PRF) treatment in patients with lumbosacral radicular pain. Methods: We have retrospectively reviewed and analyzed lumbosacral radicular pain in 34 patients who underwent PRF treatment at our institute. Diagnostic selective nerve root block was performed and patients who experienced more than 50% pain reduction were exposed to PRF. Pain relief was evaluated based on visual analog scale (VAS) scores at pre-treatment, 2 weeks, 3 and 6 months post-treatment. A success group and outcome were defined by more than 50% reduction in VAS scores at 6 months. Results: Successful outcome was achieved in 47% of patients. None of the patients had any side effects or procedure-related complications during the follow-up. Sex, number of lesions of treatment and pre-treatment VAS score showed no statistically significant differences between success and failure groups. The age of success group (52.9 ± 17.30 years) was significantly (P

Objective Although surgical intervention, such as percutaneous vertebroplasty (PVP), is the standard treatment for osteoporotic vertebral compression fractures (OVCFs), its effectiveness and safety are unclear. Therefore, this study compared the safety and efficacy of conservative treatment with that of PVP for acute OVCFs. Methods Patients with single-level OVCFs who were treated conservatively with a transdermal fentanyl patch (TFP) or with PVP between March 2013 and December 2017 and followed-up for more than 1 year were retrospectively evaluated. Patients with pathologic fractures, fractures of more than two columns, or a history of PVP were excluded. Clinical outcomes (visual analog scale [VAS] scores) and radiographic factors were evaluated, including changes in the compression rate of the corresponding vertebral body at onset and after 12 months, sagittal Cobb angle at onset and after 6 and 12 months, and the incidence of adjacent compression fractures. Results Of the 131 patients evaluated, 75 were treated conservatively using TFPs and 56 underwent PVP. We divided the patients into TFP and PVP groups. Their baseline characteristics (including sex, level of fracture, and bone mineral density T-scores) were similar, but the TFP group was significantly younger. The overall VAS score for pain showed a greater decrease during the first month (1 week after PVP) in the PVP group but remained similar in the two groups thereafter. The compression rate after 12 months increased in the TFP group but decreased in the PVP group. Five patients in the PVP group, but none in the TFP group, experienced adjacent compression fractures within 12 months. Conclusion We compared clinical and radiological outcomes between the TFP and PVP groups. The immediate pain reduction effect was superior in the PVP group, but the final clinical outcome was similar. Although the PVP group had a better-preserved compression rate than the TFP group for 1 year, the development of adjacent fractures was significantly higher. Although TFPs seemed to be beneficial in reducing the failure rate of conservative treatment, the possibility of side effects (22.6%, 17 out of 75 patients, in this study) should be carefully monitored.

Discal cysts are a rare cause of low back pain and radiculopathy with unknown pathophysiologic mechanism. Associated symptoms are difficult to distinguish from those caused by extruded discs and other spinal canal lesions. Most discal cysts are treated surgically, but it is unclear whether the corresponding intervertebral disc should be excised along with cyst. We conducted a retrospective clinical review of 27 patients who underwent discal cyst excision at our institution between 2000 and 2017. The mean follow-up period was 63.6 months. We recorded symptoms, radiographs, operative findings, postoperative complications, and short- and long-term outcomes. Structured outcome assessment was based on Numeric Rating Scale (NRS) for pain intensity, Oswestry disability index, and Macnab classification. All patients underwent partial hemilaminectomy and microscopic cyst resection without discectomy. All patients had preoperative back or leg pain. Other preoperative clinical features included motor weakness, neurogenic intermittent claudication, and cauda equina syndrome. After surgery, NRS scores of back and leg pain decreased. The other symptoms also improved. During long-term follow-up, patients reported no restrictions on daily life activities, and were satisfied with our intervention. There were no cases of cyst recurrence. We conducted a review of the literature on lumbar discal cysts published before January, 2018. Including our cases, 126 patients were described. We compared two surgical modalities—cystectomy with and without discectomy—to elucidate both effectiveness and long-term complications. We found that microsurgical cystectomy without corresponding discectomy is an effective surgical treatment for lumbar discal cysts, and is associated with a low recurrence rate.

Anterior odontoid screw fixation (AOSF) is difficult and challenging to perform in patients with type 2 odontoid fracture with a kyphotic angulation or an anterior down-slope. To demonstrate two surgical techniques to resolve kyphotic angulation or difficult fracture direction issues. Anterior odontoid screw fixation was performed in two patients with type 2 odontoid fracture with a kyphotic angulation or an anterior down-slope. This technique can avoid sternal blocking using a percutaneous vertebroplasty puncture needle, and can reduce the kyphotic angle using a Cobb elevator in patients with type 2 odontoid fractures with a kyphotic angulation or an anterior down-sloped fracture. In both the patients, AOSF was successfully performed and a successful clinical outcome was achieved. The screws were well-maintained with reduced fracture segment and well-preserved, corrected kyphotic angles were achieved, as observed on cervical X-ray 6 months postoperatively. Our technique is a safe and effective method for the treatment of type 2 odontoid fracture with a kyphotic angulation or an anterior down-slope.

Cerebral vasospasm (CAV) is a major complication of aneurysmal subarachnoid hemorrhage (aSAH) in patients with ruptured intracranial aneurysm. Explainable artificial intelligence (XAI) was used to analyze the contribution of risk factors on the development of CAV. We obtained data about patients (n = 343) treated for aSAH in our hospital. Predictive factors including age, aneurysm size, Hunt and Hess grade, and modified Fisher grade were used as input to analyze the contribution and correlation of factors correlated with CAV using a random forest regressor. An analysis conducted using an XAI model showed that aneurysm size (27.6%) was most significantly associated with the development of CAV, followed by age (20.7%) and Glasgow coma scale score (7.1%). In some patients with an estimated artificial intelligence-selected CAV value of 51%, the important risk factors were aneurysm size (9.1 mm) and location, and hypertension is also considered a major influencing factor. We could predict that Fisher grade 3 contributed to 20.3%, and the group using Antiplatelet contributed to 12.2% which is expected to lower cerebral CAV compared to the Control group (16.9%). The accuracy rate of the XAI system was 85.5% (area under the curve = 0.88). Using the modeling, aneurysm size and age were quantitatively analyzed and were found to be significantly associated with CAV in patients with aSAH. Hence, XAI modeling techniques can be used to analyze factors correlated with CAV by schematizing prediction results in some patients. Moreover, poor Fisher grade and use of postoperative antiplatelet agent are important factors for prediction of CAV.

Objective The optimal treatment modality for cervical ossification of the posterior longitudinal ligament (OPLL) including the C2 level remains controversial. Cervical laminoplasty is a widely accepted considering of advantages such as development of few postoperative complications, including kyphosis or neck pain. We encountered seven patients with postoperative disabilities resulting from incomplete decompression after undercutting of the C2 lamina. Based on this experience, we developed a new index to determine the degree of decompression in cervical OPLL-the rostral line (R-line). Methods Total of 79 consecutive patients who underwent posterior decompression of cervical OPLL were included in this study. Mean age at the time of operation, the C2-C7 cervical lordotic angle and OPLL thickness at the most stenotic level of the spinal canal, and preoperative/postoperative Japanese Orthopedic Association score was checked in these group. We compared the correspondence between the degree of C2 lamina decompression using the R-line and actual degree of decompression. Results In all patients, the R-line touched the upper half of the C2 lamina on preoperative magnetic resonance imaging (MRI). The C2-C3 local segment lordotic angle and maximal degree of spinal cord compression by OPLL were independently correlated to postoperative C2 cord shifting. This result indicates that the R-line is a valid indicator to determine the degree of C2 lamina decompression in OPLL extending to the C2 level. Conclusion The results showed that undercutting the C2 lamina can result in incomplete spinal cord decompression and poor clinical outcome if the R-line touches the upper half of the C2 lamina on preoperative MRI.

Aim We sought to evaluate the usefulness of the rostral line (R-line) as a new index for determining the degree of C2 lamina decompression in the context of ossification of the posterior longitudinal ligament (OPLL) extending to the C2 level. Material and methods The R-line was devised based on the mechanism by which the cord is shifted backward following cervical posterior decompression. According to their R-line status, 36 patients with cervical OPLL extending to the C2 level were divided into two groups of R-line (+)and R-line (-) cases, where the R-line touched the upper half of the posterior C2 lamina in the R-line (+) group and the inferior half of the posterior C2 lamina in the R-line (-) group, respectively. Results Eighteen patients were classified as R-line (+) and 18 patients were classified as R-line (-). Total laminectomy of the C2 lamina was more common in the R-line (+) group, while dome-shape C2 laminectomy was more common in the R-line (-) group. All patients requiring reoperation were included in the R-line (+) group. Only the operation type showed a statistically significant difference according to the need for reoperation in the R-line (+) group; specifically, all patients who underwent reoperation in the R-line (+) group had dome-shape C2 laminectomy. It was determined that the risk factor for reoperation in the R-line (+) group was a history of dome-shape C2 laminectomy. Conclusion If the R-line touches the upper half of the posterior C2 lamina, total decompression of the C2 lamina should be performed.

Acute spinal cord injury (SCI) is a devastating condition that causes enormous damage to a patient's physical, mental, and economic situation and requires a multidisciplinary approach to treatment. Research on SCI has been performed for a long time, and the management of SCI has developed dramatically in recent decades as a mechanism of injury and the pathophysiology of SCI have been revealed from the primitive stage in the past. In the treatment of patients with acute SCI, there is a lot of debate regarding surgical treatment strategies and pharmacological management, such as steroid use. In particular, the efficacy of steroid use, such as methylprednisolone sodium succinate, has been increasing and decreasing and is still intensely debated. The practice guidelines reported so far for this are also at the "suggest" stage with weak recommendations. Therefore, this review aims to summarize the effects of steroid use on SCI. This review provides an overview of current practical guidelines and clinical studies on steroid use in patients with SCI.

We previously introduced C1 pedicle screw placement to treat C1-2 pathology in a patient with normal vertebral artery anatomy.1 However, we should prepare to meet various anatomic variations. Ponticulus posticus is a bony prominence arising from the posterior arch or the superior articulating process of the atlas that completely or partially encircles the vertebral artery.2 We herein report a 79-yr-old female who presented with myelopathy and was diagnosed with compressive myelopathy at the C1 level in magnetic resonance imaging. A computed tomography showed ponticulus posticus (complete type to the right side) with duplication of vertebral artery. She underwent surgical treatment of C1-2 pedicle screw placement and reduction of C1 vertebra under a microscopic view. After C1 laminectomy, both-side vertebral arteries were dissected with a microscissor. The mobilization of upper divisions of vertebral artery was identified to secure the entry point and pedicle to insert a C1 pedicle screw. After complete protection of the upper and lower divisions of vertebral artery and identification of pedicle, a C1 pedicle screw was inserted by a freehand technique. We inserted autologous bone chips in the distracted C1-2 facet joint for facet joint fusion, and the C1 vertebra was pulled out by a rod reducer. After surgery, the patient's symptoms disappeared, and no vertebral artery injury was identified in postoperative 3-dimensional computed tomography angiography. Patient consent was obtained prior to performing the procedure.

Background Severe centrum semiovale perivascular spaces (CSO-PVSs) are associated with the onset of brain atrophy and dementia. This study explored the relationship between severity of CSO-PVS and development of subdural fluid (SDF) in patients with mild traumatic brain injury (TBI), with the aim of investigating independent radiological risk factors for development of SDF. Methods The study cohort comprised 222 patients with a mean age of 51 years (64.0% men) who presented with mild TBI from January 2013 to November 2016. In this study, mild TBI was defined as a Glasgow Coma Scale (GCS) of ≥ 13, Post-Traumatic Amnesia (PTA) of

Objective We designed a method for inserting C1 pedicle screws using the direct visualization technique of the pedicle and serial dilatation technique to reduce complications and malposition of screw, and assessed the accuracy of this method. Methods Free-hand C1 pedicle screw insertion using the direct visualization technique of the pedicle and serial dilatation technique was performed on 5 consecutive patients with C1–2 instability at a single institute from March to December 2018. The method involved protecting the vertebral artery (VA) and C1 root using the Penfield No. 1, securing the entry point of the posterior arch screw and the pedicle was visible directly in Trendelenburg position. The hole at the entry point of the C1 posterior arch was serially dilated using a 2.5×3.0 mm drill bit, and the C1 pedicle screw was inserted with the free hand technique. We measured postoperative radiological parameters and recorded intraoperative complications, postoperative neurological deficits and the occurrence of occipital neuralgia. Postoperative computed tomography (CT) was performed to check screw malposition or construction failure. Results Of the 10 C1 pedicle screws on postoperative CT, 20% of screws (grade A) were in the ideal position while 80% of screws (grade B) occupied a safe position. Overall, 100% of screws were safe (grade A or B). There were no iatrogenic neurological deficits, VA injury. Conclusion Freehand placement of the C1 pedicle screw through the direct visualization technique of the pedicle and serial dilatation technique is safe and effective without intraoperative fluoroscopy guidance.

To investigate radiographic parameters to improve the accuracy of radiologic diagnosis for ossification of ligamentum flavum (OLF)-induced thoracic myelopathy and thereby establish a useful diagnostic method for identifying the responsible segment. We classified 101 patients who underwent surgical treatment for OLF-induced thoracic myelopathy as the myelopathy group and 102 patients who had incidental OLF and were hospitalized with compression fracture as the non-myelopathy group between January 2009 and December 2016. We measured the thickness of OLF (TOLF), cross-sectional area of OLF (AOLF), anteroposterior canal diameter, and the ratio of each of these parameters. Most OLF cases with lateral-type axial morphology were in the non-myelopathy group and most with fused and tuberous type in the myelopathy group. Most grade-I and grade-II cases were also in the non-myelopathy group, whereas grade-IV cases were mostly observed in the myelopathy group. The AOLF ratio was found to be the best radiologic parameter. The optimal cutoff point of the AOLF ratio was 33.00%, with 87.1% sensitivity and 87.3% specificity. The AOLF ratio was significantly correlated with preoperative neurological status. An AOLF ratio greater than 33% is the most accurate diagnostic indicator of OLF-induced thoracic myelopathy. In cases of multiple-segment OLF, confirmation of cord signal change on MRI and an AOLF measurement will help determine the responsible segment. AOLF measurement will also improve the accuracy of diagnosis of OLF-induced thoracic myelopathy in cases of grade III or extended-type axial morphology. These slides can be retrieved under Electronic Supplementary Material.

To investigate the effect of the preoperative cross-sectional area (CSA) of the semispinalis cervicis on postoperative loss of cervical lordosis (LCL) after laminoplasty. A total of 144 patients who met the inclusion criteria between January 1999 and December 2015 were enrolled. Radiographic assessments were performed to evaluate the T1 slope, C2-7 sagittal vertical axis (SVA), cephalad vertebral level undergoing laminoplasty (CVLL), preoperative C2-7 Cobb angle, and preoperative CSA of the semispinalis cervicis. The T1 slope and the summation of the CSAs (SCSA) at each level of the semispinalis cervicis correlated with LCL, whereas the C2-7 SVA, CVLL, and preoperative C2-7 Cobb angle did not. Multiple regression analysis demonstrated that a high T1 slope and a low SCSA of the semispinalis cervicis were associated with LCL after laminoplasty in patients with cervical spondylotic myelopathy (CSM). The CSA of the semispinalis cervicis at the C6 level had the greatest association with LCL, which suddenly decreased with a LCL of 10°. The best cutoff point of the CSA of the semispinalis cervicis at the C6 level, which predicts LCL > 10°, was 154.5 mm2 (sensitivity 74.3%; specificity 71.6%; area under the curve 0.828; 95% confidence interval 0.761–0.895). Preoperative SCSA of the semispinalis cervicis was a risk factor for LCL after laminoplasty. Spine surgeons should evaluate semispinalis cervicis muscularity at the C6 level when planning laminoplasty for patients with CSM. These slides can be retrieved under Electronic Supplementary Material.

Intraventricular cavernous hemangiomas are uncommon. Among them, those occurred at the foramen of Monro in the third ventricle may be of particular interest because of its rarity, development of hydrocephalus, being differentiated from other brain lesions. We present a rare case of intraventricular cavernous hemangioma at foramen of Monro which was resected through microsurgery and also review the relevant literatures.

OBJECTIVE: Spinal dysraphism defects span wide spectrum. Wound dehiscence is a common postoperative complication, and is a challenge in the current management of cerebrospinal fluid (CSF) leaks and wound healing. The purpose of this study is to evaluate the risks of CSF-related morbidity in the surgical treatment of spinal dysraphism. METHODS: Ten patients with spinal dysraphism were included in this retrospective study. The median age of the cohort was 4.8 months. To assess the risk of CSF morbidity, we measured the skin lesion area and the percentage of the skin lesion area relative to the back surface for each patient. We then analyzed the relationship between morbidity and the measured skin lesion area or related factors. RESULTS: The overall median skin lesion area was 36.2 cm(2) (n=10). The percentage of the skin lesion area relative to the back surface ranged from 0.6% to 18.1%. During surgical reconstruction, 4 patients required subsequent operations to repair CSF morbidity. The comparison of the mean area of skin lesions between the CSF morbidity group and the non-CSF morbidity group was statistically significant (average volume skin lesion of 64.4±32.5 cm(2) versus 27.7±27.8 cm(2), p

J Korean Neurosurg Soc 52 : 144-147, 2012 http://dx.doi.org/10.3340/jkns.2012.52.2.144 In the paper by Lee et al., the name of the corresponding author was given incorrectly. The correct name should be Chan-Young Choi as given above.