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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 : The period of mechanical ventilator (MV)-dependent respiratory failure after cervical spinal cord injury (CSCI) varies from patient to patient. This study aimed to identify predictors of MV at hospital discharge (MVDC) due to prolonged respiratory failure among patients with MV after CSCI.Methods : Two hundred forty-three patients with CSCI were admitted to our institution between May 2006 and April 2018. Their medical records and radiographic data were retrospectively reviewed. Level and completeness of injury were defined according to the American Spinal Injury Association (ASIA) standards. Respiratory failure was defined as the requirement for definitive airway and assistance of MV. We also evaluated magnetic resonance imaging characteristics of the cervical spine. These characteristics included : maximum canal compromise (MCC); intramedullary hematoma or cord transection; and integrity of the disco-ligamentous complex for assessment of the Subaxial Cervical Spine Injury Classification (SLIC) scoring. The inclusion criteria were patients with CSCI who underwent decompression surgery within 48 hours after trauma with respiratory failure during hospital stay. Patients with Glasgow coma scale 12 or lower, major fatal trauma of vital organs, or stroke caused by vertebral artery injury were excluded from the study.Results : Out of 243 patients with CSCI, 30 required MV during their hospital stay, and 27 met the inclusion criteria. Among them, 48.1% (13/27) of patients had MVDC with greater than 30 days MV or death caused by aspiration pneumonia. In total, 51.9% (14/27) of patients could be weaned from MV during 30 days or less of hospital stay (MV days : MVDC 38.23±20.79 vs. MV weaning, 13.57±8.40; p51.4% was a significant risk factor for MVDC (odds ratio, 7.574; p=0.039).Conclusion : As a method of predicting which patients would be able to undergo weaning from MV early, the MCC is a valid factor. If the MCC exceeds 51.4%, prognosis of respiratory function becomes poor and the probability of MVDC is increased.

Objective Considering the adverse natural history of spinal dural arteriovenous fistula (sDAVF), clinical outcomes may be worsened if the initial occlusive trial does not achieve complete fistula occlusion. We aimed to analyze the initial success rate of microsurgery and embolization and confirm the effects of initial treatment success on the clinical outcomes of sDAVF patients. In addition, we investigated the factors associated with initial treatment failure. Methods A total of 38 patients treated for sDAVF at a single institution over a 14-year period were retrospectively reviewed. Clinical outcomes according to the initial treatment modality were quantitatively analyzed. Demographic characteristics and angioarchitecture data were evaluated to identify factors associated with initial treatment failure. Results In the study population, 34 patients underwent embolization as the initial treatment, and complete occlusion of the fistula was achieved in 13 patients (38%). However, all patients who underwent microsurgery showed complete fistula occlusion. Among patients with initial treatment success, gait and micturition were improved with statistical significance (p < 0.001 each). However, in cases of initial treatment failure, only mild improvements in gait and micturition were observed, which were not statistically significant (p = 0.097 and p = 0.375, respectively). A narrow feeding artery diameter (p = 0.007) and embolization of the artery only (p = 0.002) were identified as factors associated with initial treatment failure. Conclusion To achieve symptomatic improvement and prevent neurological deterioration due to recurrence, the initial definite occlusion of the fistula is important. Despite advances in endovascular techniques, microsurgical occlusion is still superior in terms of initial complete obliteration.

OBJECTIVE To compare the anterior cervical discectomy and fusion (ACDF) and posterior cervical fusion (PCF) with wide facetectomy in the treatment of parallel-shaped bony foraminal stenosis (FS). METHODS Thirty-six patients underwent surgery due to one-or-two levels of parallel-shaped cervical FS. ACDF was performed in 16 patients, and PCF using CPS was performed in 20 patients. All patients were followed up at 1, 3, 6, and 12 months postoperatively. Standardized outcome measures such as Numeric rating scale (NRS) score for arm/neck pain and Neck disability index (NDI) were evaluated. Cervical radiographs were used to compare the C2-7 Cobb's angle, segmental angle, and fusion rates. RESULTS There was an improvement in NRS scores after both approaches for radicular arm pain (mean change -6.78 vs. -8.14, p=0.012), neck pain (mean change -1.67 vs. -4.36, p=0.038), and NDI score (-19.69 vs. -18.15, p=0.794). The segmental angle improvement was greater in the ACDF group than in the posterior group (9.4°±2.7° vs. 3.3°±5.1°, p=0.004). However, there was no significant difference in C2-7 Cobb angle between groups (16.2°±7.9° vs. 14.8°±8.5°, p=0.142). As a complication, dysphagia was observed in one case of the ACDF group. CONCLUSION In the treatment of parallel-shaped bony FS up to two surgical levels, segmental angle improvement was more favorable in patients who underwent ACDF. However, PCF with wide facetectomy using CPS should be considered as an alternative treatment option in cases where the anterior approach is burdensome.

The incidence of spinal metastasis is increasing as cancer patients live longer owing to the improvement of cancer treatments. However, traditional surgery (TS) which fixates at least 2 levels above and 2 levels below the affected vertebrae is sometimes difficult to perform as it is burdensome to the patients. In this article, we introduce our experience and strategy in treating spinal metastasis, focusing particularly on challenging cases. We retrospectively reviewed the data of 110 patients who underwent spinal surgery for metastatic spinal tumors from April 2018 to March 2020. Among them, 5 patients who received anterior approach surgery were excluded. The remaining 105 patients were enrolled. In addition to TS, we also performed cervical pedicle screw, cervicothoracic junction fixation, thoracolumbar short fixation, and decompression surgery, depending on the characteristics of the tumor. The overall survival was analyzed, and the local tumor control rate was evaluated using magnetic resonance imaging. Perioperative clinical characteristics including Spine Oncology Study Group Outcomes Questionnaire, visual analog scale, Eastern Cooperative Oncology Group performance score, and Karnofsky Performance Score were also investigated. The overall survival rate was 57.9% at 1 year, and the local tumor control rate was 81.1% after surgery. There was a statistically significant difference according to the type of the tumor in the survival analysis: the overall survival rates were 72.7% for favorable tumors and 48.6% for unfavorable tumors at 12 months after surgery (P = .04). Spine Oncology Study Group Outcomes Questionnaire, visual analog scale, Eastern Cooperative Oncology Group performance score, and Karnofsky Performance Score was improved after surgery. All surgical methods, including TS, cervical pedicle screw, cervicothoracic junction fixation, thoracolumbar short fixation, and decompression surgery, showed good clinical and radiological outcomes. Optimized surgical methods show similarly good clinical outcomes in managing spinal metastasis as TS.

Study design Retrospective comparative study. Objective The aim of this study was to compare cervical sagittal alignment after posterior fusion surgery with lateral mass screw (LMS) and cervical pedicle screw (CPS) fixation. Summary of background data LMS fixation in the subaxial cervical spine has become the preferred method of posterior cervical fusion. Although CPS has biomechanical benefits, it also has neurovascular risks. Few studies to date have compared sagittal alignment changes after posterior cervical fusion using CPS and LMS fixation. Methods From 2006 to 2017, 71 consecutive patients underwent posterior cervical fusion using CPS (n = 51) or LMS (n = 20) fixation. Patients who underwent fusion with both types of screws and those who planned to undergo additional anterior fusion surgery were excluded. The minimum follow-up period was 12 months. C2-C7 Cobb angle for cervical lordosis (CL), fusion segmental angle (SA), C2-C7 sagittal vertical axis (SVA), and T1 slope (T1S) were measured. Results Immediate postoperative SA and SVA differed significantly in patients who underwent CPS and LMS fixation. SA changes were more substantial after CPS fixation, with a significant difference maintained until final follow-up. Over time, CL, SVA, and T1S tended to return to their preoperative states regardless of screw type. Two patients who underwent LMS fixation, but none who underwent CPS fixation, required unplanned or additional anterior fusion surgery for revision. Conclusion The present study is the first radiologic comparison of LMS and CPS fixation after posterior-only fusion surgery. CPS resulted in more reliable and well-preserved SA correction, whereas CL and SVA did not differ between the two groups over time due to loss of correction.Level of Evidence: 4.

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

Background: To analysis the role of gamma knife radiosurgery (GKRS) in treatment of the recurrent or residual World Health Organization (WHO) grade II and III meningiomas.Methods: Between 1995 and ...

Postoperative fever is a common feature of spinal surgery. When fever occurs postoperatively in patients, surgeons are eager to rule out an infection. There are many reports about postoperative fever and infection; however, only a few have described the relationship between degenerative spinal disease and postoperative fever. This study aimed to investigate the causes of postoperative fever in patients with degenerative lumbar disease undergoing posterior screw fixation and interbody fusion and compare patients with non-pathologic fever and infected febrile patients.From March 2015 to February 2016, 263 patients with degenerative lumbar disease underwent posterior lumbar screw fixation and interbody fusion surgery in our institution. We performed risk factor analysis by categorizing patients as afebrile and febrile. Comparisons were made between afebrile patients and patients with non-pathologic fever, and an analysis was performed between patients with non-pathologic fever and patients with febrile infection. We compared each group by examining the demographic factors before surgery, surgery features, drain duration, and postoperative transfusion. The postoperative day (POD) of fever onset, postoperative fever duration, and blood sample results in patients with fever were investigated.The drain duration was found to be an important factor between the afebrile febrile groups and between the non-pathologic fever and afebrile groups. POD of fever occurred earlier in the non-pathologic group than in the infection group (p = 0.04), and the duration of fever was shorter in the non-pathologic fever group than in the infection group (p = 0.01). Higher procalcitonin levels were observed at POD 5 in the infection group than in the non-pathologic fever group. (p 0.01) The accidental dural rupture rate was higher in the infected group (p = 0.02); this was thought to be caused by the long non-ambulatory period after surgery.This study identified risk factors and differences between infectious diseases associated with postoperative fever. A significant risk factor for postoperative non-pathological fever was a shorter catheter drainage period. Fever after 3 days, fever for more than 4 days and higher procalcitonin levels after surgery suggest infection.

Cervical pedicle screw (CPS) with O-arm-based intraoperative navigation has demonstrated satisfactory results in recent studies. In this article, we introduce our experience and discuss important considerations for CPS placement with O-arm navigation.We retrospectively reviewed the data of 51 patients with 156 pedicle screws who underwent O-arm navigated CPS from July 2020 to October 2021. The accuracy of each screw placement was evaluated at the initial screw location using intraoperative 3D reconstructed O-arm images and the final screw location using postoperative computed tomography (CT). The screw accuracy was assessed in the axial image.The initial accuracy of screws on intraoperative 3D reconstructed O-arm images was 93.6% (146 of 156). The accuracies of the mid-cervical level (C3, C4, C5) were relatively low (83.3%-85.0%) compared with those of C2, C6, and C7 (93.3%-100.0%) at the initial screw due to the rotation of the vertebral body. Among 10 violated screws, 5 were converted to lateral mass screws or removed intraoperatively, and the other 5 were retained because the violations were minimal. After converting the screw, the final accuracy of the screws in postoperative CT was 96.7% (146 of 151).CPS with O-arm navigation showed relatively low accuracy at the mid-cervical level due to vertebral rotation. However, the opportunity to convert the screw from intraoperative 3D reconstructed O-arm images is the advantage of the O-arm navigation, and it showed excellent accuracy.

BACKGROUND Despite the biomechanical benefits of subaxial cervical pedicle screw (CPS) placement, possible neurovascular complications, including vertebral artery and nerve root injury, are of great concern. We have demonstrated many times the safety and efficacy of CPS deployments, even when using freehand technology. OBJECTIVE To analyze the learning curve of CPS placement to determine the number of cases necessary for assuring safe CPS placement and to identify a reasonable accuracy rate. METHODS From March 2012 to August 2018, a single surgeon performed posterior cervical fusion surgery using CPS placement on 162 consecutive patients. We classified whole surgical periods, 6 years, into 4 periods. We analyzed the screw breach rate, lateral mass screw conversion (LMSC) rate, and reposition rate. We also compared the CPS placement accuracy in the initial 15, 20, and 30 patients with the other 147, 142, and 132 patients, respectively, to assess the number of procedures necessary to reach the learning curve plateau and to identify a reasonable accuracy rate. RESULT The total number of planned CPS placements was 979. Our learning curve showed that the breach rate plateaus at 3% to 4%. The necessary numbers for safe and accurate CPS placement during learning curve were 30 patients and 170 screws. None of the patients undergoing CPS developed a neurologic or vascular complication. CONCLUSION By following our 5 safety steps, the steady state for safety and accuracy can be reached without neurovascular complications even in the initial period of the learning curve.

Laminectomy followed by posterolateral fusion (PLF) is a standard procedure for thoracic and thoracolumbar (TL) compressive lesions. However, it is challenging to apply sufficient bone chips as the spinal cord is exposed after the laminectomy. Therefore, we performed posterior thoracic cage interbody fusion (PTCIF) as an alternative technique. A total of 25 patients operated with PTCIF technique between 2012 and 2017 were analyzed in our study. These patients required a posterior decompression and fusion in thoracic and TL spine for traumatic injury or degenerative disease. To evaluate the outcome of bone fusion, computed tomography (CT) was performed at least 3–4 months after PTCIF. The surgery was performed through insertion of screws and cages packed with autologous bone chips in a similar fashion to the posterior lumbar interbody fusion technique. Among 25 patients who underwent PTCIF, 22 patients were involved in our study. The mean age and follow-up interval were 58.6 (28–78) years and 27.1 (6–60) months, respectively. Traumatic spinal injury was diagnosed in 6 patients and degenerative disease in 16 patients. One level PTCIF was performed in 12 patients and 2 levels in 8 patients. After the operation, patients with degenerative disease showed neurological improvement, and trauma cases showed no neurological aggravation. Successful bone fusion was confirmed on CT for all patients. PTCIF is an effective treatment thereby we suggest this approach to be considered as an alternative procedure to decompression and fusion surgery in the thoracic and TL spine.

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.

Histologic grade has important implications for the management in meningioma. It is important to understand the risk of high-grade meningioma (grades II and III). In this article, we systematically reviewed the histologic grade of meningioma depending on the location and sex and its relationship with recurrence.The PubMed and Embase databases were systematically searched until February 4, 2020. We included studies that were not restricted to specific anatomic locations, histologic grade, or the sizes of the tumors. The proportion of high-grade meningiomas depending on the location and sex and the odds ratio (OR) of recurrence were pooled using a random-effects model.Outcome data were analyzed for 20,336 tumors from 34 studies. We found different proportions of high-grade meningiomas in the brain (12.8%) (95% confidence interval [CI], 10.5%-15.1%) versus the spine (2.4%) (95% CI, 1.0%-3.7%) (P0.01). Skull base meningiomas (8.7%) (95% CI, 5.8%-11.6%) had a lower proportion of high-grade meningiomas than non-skull base meningiomas (16.5%) (95% CI, 11.9%-21.1%) (P0.01). In addition, high-grade meningiomas were more likely to occur in male patients (18.0%) (95% CI, 10.1%-25.9%) than female patients (7.0%) (95% CI, 3.5%-10.6%) (P = 0.01). Higher rates of recurrence (OR = 13.83) were confirmed for high-grade meningiomas than grade I meningiomas (95% CI, 4.10-46.65) (P0.01).This meta-analysis found that intracranial, nonskull base, and male sex are risk factors for high-grade meningioma, and high-grade meningioma had a much higher recurrence rate as compared with grade I meningioma.

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.

Aim Diffuse axonal injury (DAI) is an important determining factor of morbidity and mortality after traumatic brain injury (TBI). However, its clinical outcome remains a subject of debate. Material and methods A total of 992 TBI patients visited our hospital between 2011 and 2016. Thirty-seven patients diagnosed with DAI were enrolled in this study and stratified by DAI stage: stage I, 20 patients (54.1%); stage II, 4 patients (10.8%); and stage III, 13 patients (35.1%). Results The mean age and the median follow-up period were 45.43 years and 13 months, respectively. Patient demographic data and clinical findings on admission showed no differences according to DAI stage, except for the revised trauma score (RTS) (p = 0.026). In univariate analysis, stages I and II vs. III (p = 0.001) and stages I vs. II and III (p = 0.019), transfusion within 24 hours of visit (p = 0.033), shock or cardiac arrest (p = 0.006), traumatic subarachnoid hemorrhage (T-SAH) (p = 0.011), and subdural hematoma (SDH) (p = 0.009) were significantly correlated with Glasgow outcome score (GOS). In multivariate analysis, DAI stage I and II vs. III (p = 0.005) and SDH (p = 0.040) were significant. Conclusion Clinically, stage II was more correlated with stage I, rather than stage III. Stage III showed a much poorer outcome compared to stages I and II. Magnetic resonance imaging (MRI) should be promptly performed in all TBI patients when a patient's level of consciousness and cranial computed tomography (CT) does not match, as there is a possibility of stage III DAI.

OBJECTIVE We investigated the effect of optimization in dose-limiting shell method on the dosimetric quality of CyberKnife (CK) plans in treating brain metastases (BMs). METHODS We selected 19 BMs previously treated using CK between 2014 and 2015. The original CK plans (CKoriginal) had been produced using 1 to 3 dose-limiting shells : one at the prescription isodose level (PIDL) for dose conformity and the others at lowisodose levels (10-30% of prescription dose) for dose spillage. In each case, a modified CK plan (CKmodified) was generated using 5 dose-limiting shells : one at the PIDL, another at intermediate isodose level (50% of prescription dose) for steeper dose fall-off, and the others at low-isodose levels, with an optimized shell-dilation size based on our experience. A Gamma Knife (GK) plan was also produced using the original contour set. Thus, three data sets of dosimetric parameters were generated and compared. RESULTS There were no differences in the conformity indices among the CKoriginal, CKmodified, and GK plans (mean 1.22, 1.18, and 1.24, respectively; p=0.079) and tumor coverage (mean 99.5%, 99.5%, and 99.4%, respectively; p=0.177), whereas the CKmodified plans produced significantly smaller normal tissue volumes receiving 50% of prescription dose than those produced by the CKoriginal plans (p

Objectives Surgical management of spinal cord injury (SCI) is challenging. There is no standard guideline regarding the timing of surgery, although physicians have prioritized early surgery over the past decades. Although better outcomes have been observed from these studies, the definition of early surgery has been controversial, although mostly limited to 24-hours after injury. For some hospitals, this early surgery could be difficult to implement in practice. Hence, we re-evaluated the timing of early surgery as surgery within 48 hours and investigated the surgical outcomes of SCI depending on whether surgery was performed early (≤48 hours) or late (>48 hours). The primary outcomes were improvement in the American Spinal Injury Association Impairment Scale (AIS) grade in early and late surgery groups. Methods This study was a retrospective cohort study in individuals aged 15–85 years, who underwent surgery for SCI between 2005 and 2016. The rate of AIS grade improvements was measured at 6 months after injury. Of the 86 enrolled patients, 31 (mean, 40.9 ± 12.64 hours) and 55 (mean, 168.25 ± 93.01 hours) patients were assigned to the early and late surgery groups, respectively. Results AIS grade improvement was significantly greater in the early than in the late group (P = 0.039). In the early group, there was no significant difference in neurologic improvements among the AIS B, C, and D groups, but the AIS A group showed a significant improvement (P = 0.015). This finding was not observed in the late group (P = 0.060). AIS grade improvement was also significantly greater in the incomplete SCI group than in the complete SCI group, for all measurements (early, P = 0.007, late, P = 0.009). Other factors that significantly affected clinical outcomes were AIS grade on admission and the level of the injury.

BACKGROUND Since chordoma is refractory to chemotherapy and conventional radiotherapy, radical surgical resection is mandatory. However, it is surgically demanding in the craniocervical junction (CCJ) and upper cervical spine. OBJECTIVE To analyze long-term surgical results of cervical chordomas. METHODS We retrospectively reviewed 12 consecutive patients who underwent surgical treatment for CCJ or upper cervical chordomas from 2001 to 2009 in 2 academic institutions. We analyzed the progression-free survival and overall survival and compared the results between gross total resection (GTR) cases and partial resection (PR). Complications were analyzed by comparing primary and recurrent tumor. We also delineated the type of radiotherapy. RESULTS Of the 12 patients, 5 underwent GTR and 7 underwent PR. GTR of the tumor was achieved by intralesional piecemeal removal. No recurrence occurred in the GTR group. PR group had 6 cases of regrowth (85.7%). Ten patients (83.3%) underwent any kind of radiation therapy. There were 3 (60%) patients in the GTR group and 7 (100%) in the PR group. Compared to PR, GTR revealed a better 3-yr progression-free survival rate (100% vs 14.3%) as well as a better 3-yr overall survival rate (100% vs 71.4%). Surgical complication rate (40% for GTR vs 42.9% for PR) was not significantly different between the groups. The surgical complication rates of primary and revision surgery were 25% and 75%, respectively. Complication associated with radiation occurred in 2 patients. CONCLUSION Gross total intralesional piecemeal resection with perioperative radiation therapy is an acceptable strategy for CCJ and the upper cervical chordoma management.

OBJECTIVEThe small diameter of cervical pedicles and a large transverse cervical pedicle angle are challenges that have led spinal surgeons to investigate how they could achieve a wider safety trajectory and reduce the insertion angle during cervical pedicle screw (CPS) placement. In this paper, the authors detail the advantages of using a curved pedicle probe and a laterally located entry point for overcoming these challenges.METHODSFrom March 2012 to May 2016, the authors performed posterior cervical fusions using CPSs on 119 consecutive patients. The lateral mass screw conversion and the CPS breach rate were analyzed. Using preoperative CT, it was determined that θlat is similar to the anatomical pedicle angle, and θmed is the minimally acceptable medial angle. The actual insertion medial angle (θins) was determined by postoperative CT. To identify how much of the medial angle on θins could be reduced from the anatomical pedicle angle (θlat), and how much closer to θmed, (θins−θmed) / (θlat−θmed) was calculated. To verify shifting of the entry point and widening of the trajectory, the mean df/Df (i.e., shifted facet point/planned facet point) values were analyzed.RESULTSThe total number of planed CPSs was 759, the conversion rate was 4.61% (35/759), and the accuracy rate was 95.9% (694/724). The authors could calculate that θins could be expected near the 90%, 80%, 80%, 80%, and 110% value of θlat on C-3, C-4, C-5, C-6, and C-7 levels, respectively, with the (θins−θmed) / (θlat−θmed) equation. The mean df/Df values were 0.64, 0.62, 0.63, 0.63, and 1.24 on the C3–7 levels, respectively.CONCLUSIONSThrough the use of a curved pedicle probe and a laterally located starting point, the planned and laterally located entry point medial shift was made during CPS placement. The entry point shift yielded a wider, safe trajectory and reduced the burden of making a large medial angle, similar to an anatomical cervical pedicle lateral angle, for safe CPS placement without creating a funnel-shaped hole.

The incidence of vertebral artery (VA) injury (VAI) in posterior approach tumor resection surgery is extremely rare, but it can lead to serious complication. In this case, a 57-year-old man underwent surgery for resection of the tumor involving left epidural space and neural foramen at C2-3 level. Iatrogenic VAI occurred suddenly during tumor resection procedure using pituitary forceps. Immediate local hemostasis and maintaining of perfusion for reducing the risk of posterior circulation ischemia were performed. Intraoperative angiogram of both VA and emergent trapping embolization were done as well. It may reduce the risk of immediate postop complication, and further delayed occurrence. The patient had no complication after VAI by appropriate intraoperative management. Preoperative angiographic work up and preparation of endovascular team cooperation are positively necessary as well as a warning for the VAI during cervical spine surgery.

Several studies have demonstrated the role of decompression surgery in preventing secondary injury and improving the neurological outcome after spinal cord injury (SCI). We retrospectively analyzed the prognostic factors affecting the outcomes of decompression surgery in patients with SCI.We performed one-level decompression and fusion surgery on 73 patients with cervical SCI. We classified all patients based on their interval to decompression, sex, age, surgical level, presence of high signal intensity, American Spinal Injury Association Impairment scale (AIS) before surgery, blood pressure at admission, the amount of cord compression, surgical time, estimated blood loss during surgery, and steroid use. We considered an improvement to have occurred if the patient showed an AIS improvement of ≥1 grade.Among the 73 patients with SCI we analyzed, 27 and 35 showed ≥1 grade of AIS improvement immediately and 3 months after surgery, respectively. Using multivariate analysis, the mean arterial blood pressure (MAP) was a significant prognostic factor affecting recovery in the SCI patients during the immediate post-operative period. In the late recovery period at 3 months after surgery, the AIS before surgery and the MAP were significant prognostic factors affecting recovery.Prognostic factors for AIS improvement include the initial neurological status before surgery and hemodynamic MAP at admission. The interval between decompression surgery and trauma does not affect the neurological outcome.

Objective To analyze the incidence and characteristics of delayed postoperative fever in posterior cervical fusion using cervical pedicle screws (CPS). Methods This study analyzed 119 patients who underwent posterior cervical fusion surgery using CPS. Delayed fever was defined as no fever for the first 3 postoperative days, followed by an ear temperature ≥38°C on postoperative day 4 and subsequent days. Patient age, sex, diagnosis, laminectomy, surgical level, revision status, body mass index, underlying medical disease, surgical duration, and transfusion status were retrospectively reviewed. Results Of 119 patients, seven were excluded due to surgical site infection, spondylitis, pneumonia, or surgical level that included the thoracic spine. Of the 112 included patients, 28 (25%) were febrile and 84 (75%) were afebrile. Multivariate logistic regression analysis showed that laminectomy was a statistically significant risk factor for postoperative non-pathological fever (odds ratio, 10.251; p=0.000). In contrast, trauma or tumor surgery and underlying medical disease were not significant risk factors for fever. Conclusion Patients who develop delayed fever 4 days after posterior cervical fusion surgery using CPS are more likely to have non-pathologic fever than surgical site infection. Laminectomy is a significant risk factor for non-pathologic fever.

Several studies have reported the efficacy and safety of hypofractionated stereotactic radiosurgery (hSRS) in the treatment of benign perioptic tumors. This study went further and evaluated the feasibility of hSRS in the treatment of those causing compressive cranial neuropathies (CCNs) among perioptic tumors with special consideration of functional improvement. Twenty-six patients with CCNs (CN II = 19; CN III/IV/VI = 9; CN V = 3) caused by perioptic tumors underwent hSRS between 2011 and 2015. hSRS was delivered in five fractions with a median marginal dose of 27.8 Gy (≈14 Gy in a single fraction, assuming an α/β of three) to a tumor volume of 8.2 ± 8.3 cm3. All tumors except one shrank after treatment, with a mean volume decrease of 35 % (range 4−84 %) during the mean follow-up period of 20 months. In 19 patients (38 eyes) with compressive optic neuropathy, vision improved in 55.3 % of eyes (n = 21), was unchanged in 36.8 % (n = 14), and worsened in 7.9 % (n = 3) (2.6 % after excluding two eyes deteriorated due to transient tumor swelling). A higher conformity index (p = 0.034) and volume of the optic apparatus receiving >23.0 Gy (p = 0.019) were associated with greater tumor shrinkage. A greater decrease in tumor volume (p = 0.035) was associated with a better improvement in vision. Ophthalmoplegia and facial hypesthesia improved in six of nine (66.7 %) and three of three (100 %) patients, respectively. There was no newly developed neurological deficit. Decompressive SRS for benign perioptic tumors causing CCN is feasible using hypofractionation, representing a useful alternative to microsurgical resection.

Purpose: The aims of the current study were to evaluate the effects of superficial cold and heat after spine surgery on pain, satisfaction with pain control and comfort level, and to identify subjective responses and adverse effects. Methods: A prospective, single-blind, randomized controlled trial was utilized. The intervention group (n=36) received superficial cooling until the wound drain was removed and thereafter followed by superficial heating until discharge, while the control group (n=34) received only superficial cooling until wound drain was removed. Data were collected from August 4 to November 11 2014. Results: There was significant difference in pain according to time within groups (F=71.87, p

Study design A retrospective cohort study. Objective The aim of this study was to compare the anterior odontoid screw fixation (AOSF) with a guide tube or with a straight probe. Summary of background data AOSF associates with several complications, including malpositioning, fixation loss, and screw breakage. Screw pull-out from the C2 body is the most common complication. Methods All consecutive patients with type II or rostral shallow type III odontoid fractures who underwent AOSFs during the study period were enrolled retrospectively. The guide-tube AOSF method followed the standard published method except C3 body and C2-3 disc annulus rimming was omitted to prevent disc injury; instead, the guide tube was anchored at the anterior inferior C2 vertebra corner. After 2 screw pull-outs, the guide-tube cohort was analyzed to identify the cause of instrument failure. Thereafter, the straight-probe method was developed. A guide tube was not used. A small pilot hole was made on the most anterior side of the inferior endplate, followed by insertion of a 2.5 mm straight probe through the C2 body. Non-union and instrument failure rates and screw-direction angles of the guide-tube and straight-probe groups were recorded. Results The guide-tube group (n = 13) had 2 screw pull-outs and 1 non-union. The straight-probe group (n = 8) had no complications and significantly larger screw-direction angles than the guide-tube group (60.5 ± 4.63 vs. 54.8 ± 3.82 degrees; P = 0.047). Conclusion Straight-probe AOSF yielded larger direction angles without injuring bone and disc. Complications were absent. The procedure was easier than guide-tube AOSF and assured sufficient engagement, even in horizontal fracture orientation cases. Level of evidence 3.

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.

Objective Diffuse axonal injury (DAI) is known to be associated with poor outcome. DAI often associates with other intracranial injuries but their distinct features have not been established. In this retrospective cohort study, we compared clinical outcomes between pure and non-pure DAI patients. Patients and Methods Total of 1047 traumatic brain injury (TBI) patients visited our institute between 2011 and 2017. Age ranged between 15–85 years old and Glasgow coma scale (GCS) score less than 13 were included. DAI was diagnosed in 45 patients using CT and MRI and their clinical features and outcomes were compared depending on their associated cranial injury; 20 patients without evidence of associated injury (Pure DAI group) and other 25 patients with associated injury (Non-pure DAI group). DAI stage was adopted using Gentry, L.R. classification. Glasgow outcome scale (GOS) was measured at least 6 months after trauma to evaluate their functional outcome. Results The mean age and follow-up period were 45.36 years and 15.09 months, respectively. There were no significant differences between pure and non-pure DAI groups regarding demographic data and clinical findings on their admission. Logistic regression model was used to examine the association between GOS and clinical factors. In this analysis, pure DAI was no significantly different to non-pure DAI (p = 0.607). However, DAI Stage, transfusion, and hypotension on admission were strongly related to poor outcome. Stage III showed sevenfold higher risk when compared to Stage I (p = 0.010). The risk was also high when Stage III was compare to Stage I and II (p = 0.002). Interestingly, no significant difference was observed between Stage I and II (p = 0.847). Conclusions Unfavorable outcome was observed in 14 patients (31.11%) which was lower than we expected. Interestingly, non-pure DAI was no worse than pure DAI on their functional outcome. However, DAI Stage III was independently associated with poor outcome when compared to Stage I or I and II. Finally, we concluded that Stage II is clinically more related to Stage I, rather than Stage III.

Background Standardized postoperative airway management is essential for patients undergoing anterior cervical spine surgery (ACSS). The paucity of clinical series evaluating these airway complications after ACSS has been resulted in a significant limitation in statistical analyses. Methods A retrospective cohort study was performed regarding airway distress (intubation for more than 24 hours or unplanned reintubation within 7 days of operation) developed after ACSS. If prevertebral soft tissue swelling was evident after the operation, patients were managed with prolonged intubation (longer than 24 hours). Preoperative and intraoperative patient data, and postoperative outcome (time to extubation and reintubation) were analyzed. Results Between 2008 and 2016, a total of 400 ACSS were performed. Of them, 389 patients (97.25%) extubated within 24 hours of surgery without airway complication, but 11 patients (2.75%) showed postoperative airway compromise; 7 patients (1.75%) needed prolonged intubation, while 4 patients (1.00%) required unplanned reintubation. The mean time for extubation were 2.75 hours (range: 0–23 hours) and 50.55 hours (range: 0–250 hours), respectively. Age (P = 0.015), diabetes mellitus (P = 0.003), operative time longer than 5 hours (P = 0.048), and estimated blood loss (EBL) greater than 300 mL (P = 0.042) were associated with prolonged intubation or reintubation. In prolonged intubation group, all patients showed no airway distress after extubation. Conclusion In ACSS, postoperative airway compromise is related to both patients and operative factors. We recommend a prolonged intubation for patients who are exposed to these risk factors to perform a safe and effective extubation., Graphical Abstract

OBJECT The optimal treatment for cervical facet dislocations is controversial, but the generally accepted process recommends an initial closed reduction with the next step determined according to the success of the closed reduction and the presence of traumatic disc herniation. This study aimed to show the efficacy of a posterior approach performed with an open reduction and pedicle screw fixation with removal of disc particles, if required, in the management of subaxial cervical dislocations. METHODS Between March 2012 and September 2013, 21 consecutive patients with cervical facet dislocations were enrolled. The affected levels were as follows: 4 at C3–4; 2 at C4–5; 5 at C5–6; and 10 at the C6–7 level. Seven patients had traumatic disc herniations. Closed reduction was not attempted; a prompt posterior cervical surgery was performed instead. After open reduction, pedicle screw fixation was performed. In cases with traumatic disc herniation, herniated disc fragments were excised via a posterolateral approach and successful decompressions were determined by postoperative MRI studies. Clinical outcomes were assessed using the American Spinal Injury Association (ASIA) grading system. Radiological outcomes were assessed by comparing the degree of subluxation and the angle of segmental lordosis between pre- and postoperative CT scans. RESULTS All patients improved neurologically. The mean segmental angles improved from 7.3° ± 8.68° to −5.9° ± 4.85°. The mean subluxation improved from 23.4% ± 16.52% to 2.6% ± 7.19%. Disc fragments were successfully removed from the 7 patients with herniated discs, as shown on MRI. CONCLUSIONS Open reduction followed by pedicle screw fixation or posterolateral removal of herniated disc fragments is a good treatment option for cervical facet dislocations.

Since laminoplasty was first introduced, several techniques have been developed to reduce postoperative neck pain and progressive kyphosis following this procedure. We describe the importance of deep muscle preservation to prevent postoperative neck pain following cervical posterior surgery, using the inter-muscular plane. We performed cervical laminoplasty on 10 patients from March to July 2012. The mean follow-up duration was 14.6 (range 12-18) months, and the mean age was 58.8 (48-68) years. There were eight men and two women in the study cohort, which consisted of eight cases of cervical spondylotic myelopathy and two cases of ossification of the posterior longitudinal ligament. The Japanese Orthopaedic Association (JOA) score and neck disability index (NDI) score were assessed before and at 6 and 12 months after surgery. The numeric rating scale (NRS) for neck pain was evaluated at 1, 3, 6, and 12 months after surgery. CT scan was performed immediately after the operation, and a radiograph was performed preoperatively and during the follow-up evaluation at 1, 3, 6, and 12 months after surgery. The preoperative JOA and NDI scores improved in all patients. Although there were two patients who complained of moderate postoperative neck pain (NRS 4 and 5), their condition gradually improved. Seven patients had mild or no neck pain (below NRS 3) at the 12 month follow-up. In addition, the cervical alignment was well maintained in all but one patient. Although larger prospective cohorts, longer follow-up periods, and comparative analyses are still needed, the clinical and radiological outcomes observed in the short 12 month period in this small cohort are promising.

A 56-year-old man presented with a 3-month history of progressive dizziness. His dizziness was aggravated when his head was rotated to the right side. Diagnostic angiography showed that a normal right-sided vertebral artery in the neutral position became an abnormal vertebral artery with two stenotic lesions at the C3–4 and C5–6 levels when the patient’s head was turned to the right. A normal left-sided vertebral artery also showed a stenotic lesion at the C2 level when the patient’s head was turned right. The axial dimensions of the bilateral vertebral arteries were similar. The patient was successfully treated with decompression of only one level (C5–6). We conclude that if a bilateral stenosis is found upon one directional head rotation and the bilateral vertebral arteries are similarly sized, a one-sided treatment may suffice.

Posterior lumbar interbody fusion (PLIF) using cages in conjunction with pedicle screw fixation is considered the gold standard for surgical treatment of degenerative lumbar spine disorders due to its biomechanical stability and high fusion rate. However, research regarding patterns of fusion in the interbody space during the early postoperative period is lacking. Sixty consecutive patients were recruited from May 2013 to June 2015. All patients underwent PLIF using 2 titanium cages filled with local bone chips from decompressed lamina and facet bone in conjunction with pedicle screw fixation. Computed tomography scans were obtained 3 to 6 months following surgery in order to evaluate the partial fusion state. Computed tomography (CT) classification of fusion morphology was divided into 8 groups and then into compartments according to fusion space, and the rate of fusion for each was calculated. Further follow-up was conducted to confirm fusion state and assess outcomes. The most frequent pattern of interbody fusion was bilateral intra-cage fusion with unilateral lateral bridging of extra-cage areas (N = 36, 43.4%); the least frequent was interspace bridging of the 2 cages alone (N = 0, 0%). The fusion rate for the intra-cage area (Compartment 1) reached 100%. However, the fusion in the lateral space outside of cages (Compartment 2) was not satisfactory, though reasonable (72.3%). All patients were confirmed as achieving adequate fusion at the final follow-up, with improved clinical outcomes. Widening of the contact area between the vertebral body and cages is recommended to promote increased interbody fusion during the early postoperative period.

Spinal dumbbell-shaped schwannoma is common neoplasm, usually occurring in the cervical spine. Posterior or anterolateral approaches are frequently used to remove this benign tumor. We analyzed how much amount of tumor could be possible to be totally removed with posterior approach. Surgery was performed on 41 cases of cervical, dumbbell-shaped subaxial schwannomas with both intra- and extraforaminal involvement. The same surgeon performed all the procedures. Mean follow-up was 42.5 months (24–108 months). A combined anterolateral and posterior approach was used if the extraforaminal tumor was larger than 10 mm. A posterior approach and unilateral facet removal were used if it was smaller than 10 mm. We performed MRI and serial dynamic X-rays for postoperative 2 years. We used the posterior approach with facetectomy in 35 cases and the combined approach in six. Complete removal was achieved with the combined approach in all six, and with the posterior approach in 28 of 35 cases. With the posterior approach, the extraforaminal dimension of totally resected tumors ranged from 3 to 5.4 mm. Subtotal resection was limited to extraforaminal tumors larger than 5.7 mm. On follow-up, instability on dynamic X-ray was not observed before 24 months in any patient after unilateral facetectomy. Total removal of intra- and extraforaminal cervical subaxial schwannomas could be possible using a posterior approach with facet removal if the size of extraforaminal tumor was less than 5.4 mm.