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BACKGROUND In cervical open-door laminoplasty for cervical myelopathy, a high-speed rotatory drill and rongeurs are used to make unicortical troughs and bicortical openings in the laminae. The lamina is reflected at the trough to enlarge the spinal canal, followed by bone healing on the hinge side to stabilize laminoplasty. The ultrasonic bone scalpel (UBS) has been used due to theoretical advantages including a better hinge union rate, less soft tissue trauma, less neurological injury, and shorter operative time. OBJECTIVE To assess the superiority of UBS for hinge union compared to the drill through randomized controlled trial. METHODS In 190 randomly allocated cervical myelopathy patients, the trough and opening at the lamina were made using either the drill (n = 95) or UBS (n = 95) during 2015 to 2018. The primary outcome was the hinge union rate on 6-mo postoperative computed tomography. Secondary outcomes included the hinge union rate at 12 mo, the operative time, intraoperative/postoperative bleeding, neurological injury, complications, and clinical outcomes over a 24-mo follow-up. RESULTS Hinge union in all laminae was achieved in 60.0% (drill) and 43.9% (UBS) of patients at 6 mo (intention-to-treat analysis; P = .02; odds ratio, 2.1) and in 91.9% (drill) and 86.5% (UBS) at 12 mo. Dural injury only occurred in the drill group (2.1%), and the UBS group showed significantly less intraoperative bleeding (P

Objective Subsidence of the interbody graft into the vertebral bodies is one of the major complications of direct lateral interbody fusion (DLIF), resulting in pseudoarthrosis and severe pain. Low bone mineral density (BMD) has been known to increase the risk of subsidence. This study aims to determine whether or not the osteopenia should influence the surgical results in DLIF surgery. Methods We retrospectively reviewed the data collected prospectively on all patients who underwent single-level DLIF at our institution. A total of 84 patients were included in this study, comprised of 41 in the osteopenia group and 43 in the normal BMD group. The clinical and radiologic characteristics were compared at preoperative and postoperative 1 and 2 years. Results At postoperative two years, there was a statistically significant difference in disc height and intervertebral foramen height at index level between the two groups (p = 0.039, 0.044, respectively), but there was no significant difference in total lumbar lordosis (p = 0.179). At 24-month postoperative, 92.7% of the osteopenia group and 95.3% of the normal BMD group were solidly fused (p = 0.672). All postoperative clinical scores (VAS back pain, VAS leg pain, and ODI) improved similarly in both groups without significant difference. The overall incidence of cage subsidence with >3 mm was 17.1% in the osteopenia group and 9.3% in the normal BMD group (p = 0.345). Conclusions Patients with osteopenia who undergo single-level DLIF combined with posterior fixation exhibited comparable clinical and radiological outcomes as patients with normal BMD.

Background Tumor-related white matter change is detected at late stages with magnetic reso nance imaging (MRI), when mass effect or prominent edema is present. We analyzed if diffusion tensor imaging (DTI) white matter change earlier than conventional MRI. Methods Twenty-six patients with gliomas (World Health Organization grade II, 5; grade III, 12; and grade IV, 9) within 2 cm from the posterior limb of the internal capsule (IC) were studied. Fifteen normal adults were enrolled as controls. Fluid attenuation inversion recovery MRI showed a high signal change at the posterior limb of the IC (HSIC) in 9 patients with grade III or IV gliomas. We classified the gliomas as WHO grade II (gliomas II), grade III or IV without HSIC [gliomas III/IV(-)] and grade III or IV with HSIC [gliomas III/IV(+)], as an indicator of the increase in the severity of the white matter changes. Fractional anisotropy (FA) and apparent diffusion coefficients (ADC) were calculated for the pyramidal tract. Tumor progression along pyramidal tract was evaluated by follow-up MRI in 16 patients at 40±18 months. Results FA showed no significant difference between gliomas II and control (p=0.694), but was lower in gliomas III/IV(-) and gliomas III/IV(+) (p

Although ependymomas occur in both the brain and the spine, the prognosis is quite varied by tumor location. Spinal ependymomas usually follow a relatively benign course with more favorable prognosis than that of the intracranial ependymomas. The aim of this study is to evaluate the genetic differences between spinal ependymomas and their intracranial counterparts using a meta-analysis. We searched PubMed, Embase, Web of Science, and the Cochrane library. Comparative or single arm genetic studies that enrolled patients with both intracranial and spinal ependymoma were included. The frequency of genetic aberration was calculated in each group. We calculated the odds ratio (OR) with 95 % confidence intervals (CIs) for direct comparative studies and the logit event rate (LER) and 95 % CI for single arm studies. Twenty-five studies comprising of 380 spinal ependymomas and 964 intracranial ependymomas were compared to determine the association of the genetic differences of ependymomas at different locations. There were 25 comparable genetic aberrations between spinal and intracranial ependymomas. Among the genes, the NF2 mutation was significantly associated with the spinal ependymomas rather than with the intracranial ependymomas (spinal tumor: LER −0.750, 95 % CI −1.233 to −0.266, intracranial tumor: LER −3.080, 95 % CI −3.983 to −2.177). Intracranial ependymomas were found to be significantly associated with EPB41L3 deletion (OR 0.34; 95 % CI 0.14–0.80) and HIC1 methylation (OR 0.12; 95 % CI 0.02–0.68). The genetic aberrations of spinal ependymomas are quite different from those of intracranial ependymomas. The difference in prognosis of ependymoma by location may be associated with genetic difference. A more detailed understanding of them may enable the development of targeted therapy and the estimation of prognosis.

Study Design: Technical report. Objective: To present a detailed surgical technique for percutaneous endoscopic interlaminar discectomy (PEID) for highly migrated disk herniation. Summary of Background Data: Percutaneous lumbar endoscopic discectomy for highly migrated disk herniation is still challenging even for an experienced surgeon. Because of the risk of failure and technical difficulty, open discectomy is recommended for a high-grade migration. However, past reports focused on the transforaminal approach (percutaneous endoscopic transforaminal discectomy) and may give a biased impression. We may overlook the merit of PEID. The surgical procedure for PEID is similar to a traditional open discectomy and the range of approach could be widened by the inclined introduction and pivoting motion of an endoscope. Methods: Eighteen consecutive patients (M:F=12:6; age, 56±15 y) with highly migrated disk herniation were enrolled for the present study. The disk material was migrated superiorly in 7 patients (L4–5, 4; L5–S1, 2; L2–3, 1) and inferiorly in 11 patients (L4–5, 6; L3–4, 4; L5–S1, 1). PEID was applied in 17 patients and PETD was performed for L2–3 disk herniation. The follow-up period was 16±12 months. The outcome was graded using the MacNab criteria. Results: Complete removal of the disk material was confirmed with magnetic resonance imaging in 16 patients (success rate 89%). Revision operation was necessary in 2 patients with inferior migration from L4–5. The residual disk was removed through the L5–S1 laminar window 2 days after surgery with excellent outcome at the last follow-up. The outcome at the last follow-up was excellent in 12 patients, good in 3, fair in 2, and poor in 1. Dural tear was suspected in 1 patient without any further problems and there was no recurrence during follow-up. Conclusions: PEID may be applied comfortably even for less-experienced surgeons because of the familiar anatomy with open surgery.

Objectives The aim of this study was to evaluate and compare the advantages of post-tetanic motor-evoked potential (p-MEP) and conventional motor-evoked potential (c-MEP) in terms of MEP inter-trial variability and accuracy. Methods c-MEP and p-MEP were quantified in subjects who underwent brain surgery. c-MEP was generated by transcranial electrical stimulation (TES). p-MEP was generated using a preconditioning process involving tetanic stimulation at the left tibial nerve followed by TES. The presence of significant MEP deterioration was monitored during major surgical process. An additional 5–8 MEP obtained after major surgical process were used to analyze amplitude parameters such as mean, standard deviation, range, coefficient of variation (CV), and range to mean ratio. Results When only irreversible MEP deteriorations were considered as positive results, the false-positive rate was identical for p-MEP and c-MEP. When total MEP deteriorations were considered as positive results, the false-positive rate of p-MEP was lower and p-MEP had higher specificity than c-MEP. The mean amplitude of p-MEP was significantly higher than that of c-MEP. The CV and range to mean ratio of p-MEP were less than those of c-MEP. Conclusion The p-MEP technique is useful for augmenting MEP amplitude and reducing inter-trial variability. Significance p-MEP has clinical significance as a useful technique for intraoperative monitoring.

Objective: A fibrin sealant is commonly applied after closure of an incidental or intended durotomy to reduce the complications associated with the leakage of cerebrospinal fluid. Routine usage might not be essential after closure of an intended durotomy, which has clear cut-margins. We investigated the efficacy of fibrin sealants for primary intradural spinal cord tumor surgery. Methods: A retrospective review was performed for 231 consecutive surgically treated patients with primary intradural spinal cord tumors without extradural extension. Fibrin sealants were not used for 47 patients (group I: age, 51.57±16.75 years) and were applied to 184 patients (group II: age, 48.8±14.7 years). The surgical procedures were identical except for the use of a fibrin sealant after closure of the durotomy. The primary outcome was the occurrence of complications (wound problems, hematoma collection, infection, and neurological deterioration). The covariates were age, sex, body mass index, operation time, pre-/ postoperative ambulation, number of laminectomies, and type of tumor. Results: Schwannoma was the most common pathology (n=134), followed by meningioma (n=35) and ependymoma (n=31). Complications occurred in 13 patients (3 in group I and 10 in group II, p=0.73). The postoperative ambulation status (p

Background Context Selective estrogen receptor modulators (SERMs) are drugs used to treat osteoporosis. Selective estrogen receptor modulators improve bone mineral density and bone mechanical strength. However, there is a lack of data on the effect of SERMs on osteoporotic spinal fusion. Purpose This study aimed to investigate whether treatment with a SERM enhances spinal fusion in an ovariectomized (OVX) rat model. Study Design An in vivo animal study was carried out. Methods Female Sprague Dawley rats (n=90) were OVX or sham-operated, and randomized into three groups: control (sham-operated+fusion procedure+saline administration), OVX (OVX+fusion procedure+saline administration), and SERM (OVX+fusion procedure+administration of SERM). Eight weeks after OVX, a bilateral lumbar spinal fusion procedure was performed using autologous iliac bone. In each group, gene expression was evaluated at 2, 4, and 8 weeks after the fusion procedure, histologic analysis was performed at 4 and 8 weeks after the procedure, and bone parameters were measured by micro-computed tomography at 2 days, 4 weeks, and 8 weeks after the procedure. Results Bone mineral density and trabecular quality of the vertebral body were significantly higher in the SERM group compared with the OVX group 16 weeks after OVX. The fusion rate and bone volume ratio were higher in the fusion bed of the SERM group compared with the OVX group 8 weeks after the fusion procedure. Real-time reverse transcription polymerase chain reaction at 4 and 8 weeks after the fusion procedure showed increased expression of the genes for osteoblast-related markers (alkaline phosphatase, osteocalcin, runt-related transcription factor 2, and transforming growth factor) in the SERM group compared with the OVX group. The OVX group showed sparse bone mass between transverse processes. By contrast, the SERM group exhibited a compact bridging fusion mass within the fusion bed at 8 weeks after the fusion procedure. Conclusions Selective estrogen receptor modulator treatment improved the trabecular quality of the vertebral body, enhanced spinal fusion, and increased the amount of compact bone mass within the fusion bed in rats that had received an ovariectomy. Therapeutic SERM treatment may be recommended to improve the fusion rate in osteoporotic patients who undergo spinal fusion.

Objective The reoperation rate after lumbar degenerative disease surgery is low. It is difficult to find statistical differences in reoperation rates according to the different diagnoses of lumbar degenerative diseases. National population-based database overcomes the statistical problem by its large cohorts with longitudinal follow-up in a nation. The purpose was to compare the reoperation rates after single-level lumbar spinal posterior decompression and fusion surgeries depending on different preoperative diagnoses of lumbar degenerative disease. Patients and methods: We used the Korean Health Insurance Review & Assessment Service national database. The study population was the patients with a diagnosis of a degenerative lumbar disease who underwent single-level decompression and fusion from January 1, 2011, to June 30, 2016. We classified the patients into one of three groups based on diagnosis codes of lumbar disc herniation, spondylolisthesis, or spinal stenosis. A reoperation was defined as repeated decompression and fusion. We considered age, sex, the presence of diabetes, osteoporosis, associated comorbidities, and hospital types as potential confounding factors. Results The reoperation rate was higher in patients with spinal stenosis than in those with lumbar disc herniation. However, there was no difference in the reoperation rate between the patients with lumbar disc herniation and those with spondylolisthesis. Male gender and hospital type were risk factors for reoperation. Conclusion The incidence of reoperation was dependent on the diagnostic subgroups of lumbar degenerative diseases. This information can help surgeons accurately communicate with their patients and enhance the preoperative informed consent process.

There is a low incidence of reoperation after surgery. It is difficult to detect statistical differences between reoperation rates of different lumbar fusion surgeries. National population-based databases provide large, longitudinally followed cohorts that may help overcome this challenge. The purpose is to compare the repeat decompression and fusion rate after surgery for degenerative lumbar diseases according to different surgical fusion procedures based on national population-based databases and elucidate the risk factor for repeat decompression and fusions. The Korean Health Insurance Review & Assessment Service database was used. Patients diagnosed with degenerative lumbar diseases and who underwent single-level fusion surgeries between January 1, 2011, and June 30, 2016, were included. They were divided into two groups based on procedure codes: posterolateral fusion or posterior/transforaminal lumbar interbody fusion. The primary endpoint was repeat decompression and fusion. Age, sex, the presence of diabetes, osteoporosis, associated comorbidities, and hospital types were considered potential confounding factors. The repeat decompression and fusion rate was not different between the patients who underwent posterolateral fusion and those who underwent posterior/transforaminal lumbar interbody fusion. Old age, male sex, and hospital type were noted to be risk factors. The incidence of repeat decompression and fusion was independent on the fusion method.

Residual disc fragments are observed on immediate postoperative magnetic resonance imaging (MRI) in 2.8-15% of patients after percutaneous endoscopic lumbar discectomy (PELD). Considering the known postoperative longitudinal outcomes in patients with residual disc tissue, a 'watchful waiting' strategy may be preferable to immediate re-operation in patients with asymptomatic residual disc material.The aim of the present study was to compare the longitudinal clinical outcomes between PELD patients in whom the complete removal of disc fragments was achieved (complete group) and those in whom residual disc fragments were observed on postoperative MRI (residual group).Retrospective nested case-control study.A total of 225 patients were included (complete group, n=187 and residual group, n=38). Clinical assessments were performed using the visual analog pain score for the leg (VAS-L, x/10) and back (VAS-B, x/10) and the Korean version of the Oswestry Disability Index (K-ODI, x/45). A linear mixed-effects model was used to analyze changes during the first 24 postoperative months.One month after surgery, significant improvements in the VAS-L, VAS-B and K-ODI values were observed and were maintained during the first 24 postoperative months. No differences in these changes were noted between the groups. Early re-operation (during the first 3 postoperative months) was performed in 3 patients in the residual group (7.9%) and in 4 patients in the complete group (2.1%) (P = 0.10).First, the study design was retrospective. Moreover, the number of patients was relatively small and therefore insufficient to achieve robust statistical power. Second, we did not explore the radiological outcomes in patients with asymptomatic residual disc material because follow-up MRI was only obtained to document symptom recurrence.When residual disc tissue is observed in asymptomatic patients, a 'watchful waiting' strategy may be preferable to immediate re-operation. However, an increased early re-operation rate is expected for patients with residual disc tissue.Discectomy, endoscopes, longitudinal studies, patient-reported outcome, percutaneous, reoperation, spine, residual disc.

A meta-analysis of five retrospective cohort studies.The aim of the study was to delineate the efficacy and safety of full-endoscopic decompression via the interlaminar approach for central or lateral recess spinal stenosis of the lumbar spine using a meta-analysis.The paradigm of spinal endoscopy is shifting from treatment of soft disc herniation to that of lumbar spinal stenosis. Technical advancements have enabled full-endoscopic decompression in spinal stenosis surgery. There is few strong evidence supporting this surgical technique, and clinicians usually rely on their own opinions and experiences.A systematic search of electronic databases, including PubMed, EMBASE, Cochrane Library, Web of science, and KoreaMed, up to August 2017 was performed to identify studies concerning full-endoscopic decompression via the interlaminar approach for lumbar spinal stenosis. Changes in clinical outcomes [Oswestry Disability Index (ODI) and Visual Analog Scales (VAS) for back and leg pain] were compared with the minimal clinically important difference (MCID) for each item. We then calculated the mean differences and 95% confidence intervals (95% CIs) using random-effects models.We included data from five studies involving 156 patients at 6- and 12-month follow-ups. The majority of enrolled papers included patients with neurogenic claudication due to central stenosis refractory to conservative management and excluded patients with significant instability or previous surgery. The overall mean difference of patients with ODI and VAS scores for leg and back pain exceeded the criteria for MCID. ODI scores improved by 41.71 (95% CI, 39.80-43.62) after the surgery, which was twice the MCID. The VAS leg and back pain scores improved by 5.95 (95% CI, 5.70-6.21) and 4.22 (95% CI, 3.88-4.56), respectively, indicating statistically significant improvement over the MCID.Successful clinical outcomes can be achieved with full-endoscopic decompression via the interlaminar approach for lumbar central spinal stenosis in patients for the defined indications.2.

Objective Examining spine surgery patterns over time is crucial to provide insights into variations and changes in clinical decision making. Changes in the number of surgeries, surgical methods, reoperation rates, and cost-effectiveness were analyzed for all patients who underwent surgery for lumbar spinal stenosis without spondylolisthesis in 2003 (2003 cohort) and 2008 (2008 cohort). Methods The national health insurance database was used to create the 2003 cohort (n = 10,990) and 2008 cohort (n = 27,942). The surgical methods were classified into decompression and fusion surgery. The cumulative reoperation probability between those surgeries was calculated using the Kaplan-Meier method in the 2003 cohort and 2008 cohort. Comparison of the incremental cost-effectiveness ratios showed the additional direct cost of a 1% change in the reoperation probability. Results The surgical volume increased 2.54-fold in the 2008 cohort. The age-adjusted number of surgeries per 1 million people increased 2.6-fold (from 154 in the 2003 cohort to 399 in the 2008 cohort) in aged patients and 1.9-fold (from 154 in the 2003 cohort to 291 in the 2008 cohort) in patients 20–59 years old in the 2008 cohort. The proportion of fusion surgeries increased from 20.3% in the 2003 cohort to 37.0% in the 2008 cohort. In total, the 5-year reoperation probabilities increased from 8.1% in the 2003 cohort to 11.2% in the 2008 cohort. Fusion decreased the reoperation probability by 1% at the cost of 1,711 U.S. dollars. Conclusions The increased numbers of spinal surgeries, fusion surgeries, and surgeries in older patients in a recent cohort were noteworthy. However, the increased surgical volume and fusion surgeries did not reduce the reoperation rate.

Background Context Diabetes and menopause can cause severe osteoporosis. In general, menopause and diabetes can lead to an imbalance in bone turnover, which results in secondary osteoporosis. However, the efficacy of antiresorptive drugs against this form of osteoporosis has not been extensively evaluated. Objective The aim of this study was to determine the changes in vertebral bone remodeling when postmenopausal osteoporosis is accompanied by diabetes and to compare the efficacy of bisphosphonates and selective estrogen-receptor modulators (SERMs) against these outcomes. Study design Streptozotocin-induced diabetic, ovariectomized Sprague-Dawley rats were used as the disease model. Alendronate and raloxifene were used as the bisphosphonate and SERM, respectively. Methods We divided 62 female rats into five groups: (1) control (n=14), (2) DM (diabetes) (n=12), (3) DM+OVX (diabetes+ovariectomy) (n=12), (4) DM+OVX+A (diabetes+ovariectomy+alendronate) (n=12), and (5) DM+OVX+R (diabetes+ovariectomy+raloxifene) (n=12). Serum biochemical markers of bone turnover, including osteocalcin and the C-telopeptide of type I collagen (CTX-1), were analyzed. We measured histomorphometric parameters of the fourth lumbar vertebrae using microcomputed tomography. Mechanical strength was evaluated by a compression test. Results In the DM and DM+OVX group, only the levels of osteocalcin significantly decreased compared with those of the control group at 8 weeks after OVX. At 12 weeks, the serum CTX-1 levels in the DM+OVX+A and DM+OVX+R groups were significantly lower than those of the DM+OVX group, but there were no changes in the levels of osteocalcin. Bone mineral density and mechanical strength were higher in the DM+OVX+A and DM+OVX+R groups than in the DM and DM+OVX groups (p Conclusions Even if postmenopausal osteoporosis is accompanied by diabetes in this animal model, both alendronate and raloxifene seem to show antiresorptive effects, decreased bone turnover rates, and improved bone mechanical strength. Therefore, alendronate and raloxifene are effective in the treatment of osteoporosis even for bone loss caused by DM and postmenopausal osteoporosis.

Transforaminal lumbar interbody fusion (TLIF) is a widely accepted surgical procedure, but cage migration (CM) and cage retropulsion (CR) are associated with poor outcomes.This study seeks to identify risk factors associated with these serious events.A prospective observational longitudinal study.Over a 5-year period, 881 lumbar levels in 784 patients were treated using TLIF at three spinal surgery centers.We evaluated the odds ratio of the risk factors for CM with and without subsidence and CR in multivariate analysis.Our study classified CM into two subgroups: CM without subsidence and CM with subsidence. Cases of spinal canal and/or foramen intrusion of the cage was defined separately as CR. Patient records, operative notes, and radiographs were analyzed for factors potentially related to CM with subsidence, CM without subsidence, and CR.Of 881 lumbar levels treated with TLIFs, CM without subsidence was observed in 20 (2.3%) and CM with subsidence was observed in 36 (4.1%) patients. Among the CM cases, CR was observed in 17 (17/56, 30.4%). The risk factors of CM without subsidence were osteoporosis (OR 8.73, p.001) and use of a unilateral single cage (OR 3.57, p.001). Osteoporosis (OR 5.77, p.001) and endplate injury (OR 26.87, p.001) were found to be significant risk factors for CM with subsidence. Risk factors of CR were osteoporosis (OR 7.86, p.001), pear-shaped disc (OR 8.28, p = .001), endplate injury (OR 18.70, p.001), unilateral single cage use (OR 4.40, p = .03), and posterior cage position (OR 6.45, p = .04). A difference in overall fusion rates was identified, with a rate of 97.1% (801 of 825) for no CM, 55.0% (11 of 20) for CM without subsidence, 41.7% (15 of 36) for CM with subsidence, and 17.6% (3 of 17) for CR at 1.5 years postoperatively.Our results suggest that osteoporosis is a significant risk factor for both CM and CR. In addition, a pear-shaped disc, posterior positioning of the cage, the presence of endplate injury and the use of a single cage were correlated with the CM with and without subsidence and CR.

Background: Some patients with lumbar herniated intervertebral disc disease (HIVD) suffer from both pain and lateral shift or trunk list. In addition to pain, patients have concerns regarding whether trunk list is reversible. Surgical treatment is performed when pain is intractable to conservative management, but a reversal of trunk list is an incidental outcome. Percutaneous lumbar endoscopic discectomy (PELD) is one of the surgical treatment options for lumbar HIVD, but no results concerning its effect on trunk list have been reported. Objectives: The objectives of the present study were to determine the incidence of, and risk factors for, trunk list scoliosis or lateral shift and to report the outcomes of trunk list after PELD. Study Design: Retrospective case study. IRB No. H 1111-025-384 Setting; University medical Center, Seoul, Korea. Methods: We selected 164 patients who were less than 60 years old, complained of unilateral leg pain, and underwent PELD. We measured the maximum trunk shift from the central sacral vertical line (CSVL-max) on preoperative whole spine radiographs and classified trunk list as CSVL-max ≥ 10 mm. CSVL-max was measured on serial radiographs taken at one, 3, 6, and 12 months postoperatively in patients with trunk list. Results: Twenty-nine patients (17.9%) had trunk list (M:F=10:19; mean age, 37.1 ± 11.24 years). Female gender (OR 4.28; 95% CI, 1.49 – 12.3) and HIVD at L4-5 (OR 5.6; 95% CI, 1.8 - 16.7) were risk factors for trunk list. Trunk list was normalized (CSVL-max < 10 mm) in 15 (52%) patients after PELD, and the median time for normalization was 3 – 6 months. Prognostic factors for the recovery of trunk list were not identified. Limitations: Selection bias should be considered in interpreting these results. Conclusion: Trunk list, scoliosis or lateral shift, was observed in 18% of the patients at the time of surgery. Female gender and L4-5 disc herniation were risk factors for trunk list. Trunk list was reversible in more than 50% of patients within 6 months of PELD. Key words: Lumbar, scoliosis, lumbar/sciatic, trunk list, endoscope, disc, discectomy, sciatica, spine, percutaneous endoscopic discectomy

Simpson grade II removal (coagulation of the dural attachment after gross total removal) of spinal meningioma is considered an acceptable alternative, but increased recurrence after more than 10 years has been reported. More attention must be paid to the long-term surgical outcomes after Simpson grade II removal. A retrospective review was performed for 20 patients (M:F = 5:15; age, 59 ± 9 years) with Simpson grade II removal (mean follow-up period, 12.9 years; range 10.0–17.5). Magnetic resonance (MR) imaging was conducted in 17 patients at 88 ± 52 months (range 12–157). During the same period, Simpson grade I removal (removal of the dural origin) was performed in 21 patients (follow-up, 89 ± 87 months; range 9–316). Radiological recurrence was defined as a visible tumor on a follow-up MR image, and clinical tumor recurrence was defined as the recurrence of symptoms. At the final follow-up, neurological symptoms had improved in 16/20 patients and remained stable in 4/20. A recurrent tumor was detected in one patient due to increased back pain at 92 months postoperative, but the symptom was stable without surgery until the last follow-up (124 months). The radiological and clinical recurrence-free survival periods were 150 ± 7 months (95 % CI 136–163) and 204 ± 6 months (95 % CI 193–215), respectively. There was no recurrence after Simpson grade I removal, whereas neurological deterioration occurred in two patients after surgery. Simpson grade II removal may be an alternative option if the risk of complications with Simpson grade I removal is expected to be high.

A high cervical dural arteriovenous fistula (dAVF) is relatively rare and tends to have different features, as compared with a thoracolumbar dAVF. Here, we report a case involving a complex AVF located at the craniocervical junction that was fed by the dural and pial arteries, combined with a contralateral dAVF.

Study design Retrospective cohort study. Objective To provide an age cut-off of percutaneous endoscopic lumbar discectomy (PELD) for optimal reoperation rate with nationwide population-based data. Summary of background data Open discectomy is the standard operation for lumbar herniated intervertebral disk disease (HIVD). PELD has shown noninferior outcome to open discectomy and there is increasing interest with regard to PELD. However, PELD may not be a suitable option for all age groups. Methods We selected 15,817 patients who underwent open discectomy (n = 12,816) or PELD (n = 3001) in 2003 from the Korean Health Insurance Review & Assessment Service (HIRA) database. All patients in the cohort were followed until December 31, 2008, and the minimum follow-up period was 5 years. A time-to-event survival analysis was conducted. The primary endpoint was any type of second lumbar spine surgery during the follow-up period. Minimum P-value approach and a 2-fold cross-validation approach were utilized to determine an age cut-off point. Results The optimal age cut-off point was determined as 57 years. PELD for older patients (≥57 years) had a higher reoperation risk during the postoperative 3.4 years (hazard ratio [HR] at 1 yr, 1.75; 2 yr, 1.57; and 3 yr, 1.41). However, the reoperation risk was not higher after PELD for patients younger than 57 years, from 1.9 years, than open discectomy (HR at 2 yr, 0.86; 3 yr, 0.78; 4 yr, 0.70; and 5 yr, 0.63). Conclusion In the present study, we showed that an age cut-off point of PELD for optimal reoperation rate may be 57 years, based on nationwide population-based data. The reoperation rate does not seem to be higher for patients younger than 57 years after PELD than after open discectomy; however, PELD for older patients should be applied after careful consideration. Level of evidence 3.

BACKGROUND: Precentral gyrus resections (PGRs) have been regarded as excessively hazardous interventions because of the risk of postoperative major neurological complications. OBJECTIVE: To evaluate the neurological deterioration that follows PGRs and to assess the topographical risk factors associated with these morbidities. METHODS: We reviewed 33 consecutive patients who experienced pharmacologically intractable epilepsy and underwent PGR with intraoperative cortical stimulation and mapping while under awake anesthesia. The etiological diagnoses were brain neoplasm in 26 patients (78.8%), cortical lesion in 4 (12.1%), and no lesion in 3 (9.1%). The mean follow-up period was 62.6 months (range, 12-146 months). All topographical analyses of the resected quadrant area were performed based on postoperative magnetic resonance images. RESULTS: After PGR, 22 patients (66.7%) experienced neurological worsening, including 5 permanent deficits (15.2%) and 17 transient deficits (51.5%). Permanent deficits included 2 instances of weakness, 1 dysarthria, 1 dysesthesia, and 1 fine-movement disturbance of the hand. While the neurological risk for anterior lower quadrant PGR was 20.0% (1/5), the risk for posterior upper quadrant PGR was 100.0% (10/10). The anterior upper and posterior lower quadrant PGR caused neurological deteriorations in 60.0% (6/10) and 62.5% (5/8) of the patients, respectively. In a multivariate analysis, PGR of the posterior and upper quadrant sections were significant risk factors for post-PGR neurological deteriorations (P = .022 and 0.030, respectively). CONCLUSION: The posterior upper quadrant of the precentral gyrus was vulnerable to post-resective neurological impairment.

Occasionally, unexpected neurological deficits occur after lumbar spinal surgery. We report a case of monoparesis after lumbar decompressive surgery. A 63-year-old man, who had undergone decompression of L4-5 for spinal stenosis 4 days previously in the other hospital, visted the emergency department with progressive weakness in the left leg and hypoesthesia below sensory level T7 on the right side. He had been cured of lung cancer with chemotherapy and radiation therapy 10 years previously, but detailed information of radiotherapy was not available. Whole spine magnetic resonance (MR) imaging showed fatty marrow change from T1 to T8, most likely due to previous irradiation. The T2-weighted MR image showed a high-signal T4-5 spinal cord lesion surrounded by a low signal rim, and the T1-weighted MR image showed focal high signal intensity with focal enhancement. The radiological diagnosis was vascular disorders with suspicious bleeding. Surgical removal was refused by the patient. With rehabilitation, the patient could walk independently without assistance 2 months later. Considering radiation induced change at thoracic vertebrae, vascular disorders may be induced by irradiation. If the spinal cord was previously irradiated, radiation induced vascular disorders needs to be considered.

Congenital craniocervical segmentation anomaly associated with malalignment of the odontoid process causes progressive spinal cord compression with myelopathy. Recent literatures have reported that ventral decompression could be achieved with posterior craniocervical realignment through posterior instrumented reduction. The purpose of the present study is to show the efficacy of intraoperative electrophysiological monitoring during craniocervical realignment through screws and rod system for congenital craniocervical segmentation anomaly. Consecutive ten patients with a congenital craniocervical segmentation anomaly and myelopathy due to a malaligned odontoid process, who underwent posterior craniocervical realignment, were included. Klippel–Feil syndrome (KFS) was combined in four patients. Gait disturbance and motor weakness were the main presentation. Craniocervical realignment was achieved by intraoperative distraction through a rod and screw system. Intraoperative neuromonitoring was performed with transcranial motor-evoked potential (TcMEP) and somatosensory-evoked potential (SSEP). Significant change in TcMEP occurred in two patients with KFS during surgery, but the change was reversed with release of distraction. All patients were awakened without neurological deficit. Motor weakness and gait disturbance were normalized within 6 months in all patients. Postoperative computed tomography scan and/or magnetic resonance imaging showed that the reduction was complete in all patients. Craniocervical realignment through screws and rod system may be safe and efficacious surgical technique for the treatment of congenital craniocervical anomaly with the help of intraoperative neuromonitoring. However, distraction should be cautiously monitored, especially when Klippel–Feil syndrome is combined.

Study design Retrospective comparative study. Objective Two polyetheretherketone (PEEK) cages of different designs were compared in terms of the postoperative segmental kyphosis after anterior cervical discectomy and fusion. Summary of background data Segmental kyphosis occasionally occurs after the use of a stand-alone cage for anterior cervical discectomy and fusion. Although PEEK material seems to have less risk of segmental kyphosis compared with other materials, the occurrence of segmental kyphosis for PEEK cages has been reported to be from 0% to 29%. There have been a few reports that addressed the issue of PEEK cage design. Method A total of 41 consecutive patients who underwent single-level anterior discectomy and fusion with a stand-alone cage were included. Either a round tube-type (Solis; 18 patients, S-group) or a trapezoidal tube-type (MC+; 23 patients, M-group) cage was used. The contact area between the cage and the vertebral body is larger in MC+ than in Solis, and anchoring pins were present in the Solis cage. The effect of the cage type on the segmental angle (SA) (lordosis vs. kyphosis) at postoperative month 24 was analyzed. Results Preoperatively, segmental lordosis was present in 12/18 S-group and 16/23 M-group patients (P=0.84). The SA was more lordotic than the preoperative angle in both groups just after surgery, with no difference between groups (P=0.39). At 24 months, segmental lordosis was observed in 9/18 S-group and 20/23 M-group patients (P=0.01). The patients in M-group were 7.83 times more likely than patients in S-group (P=0.04; odds ratio, 7.83; 95% confidence interval, 1.09-56.28) not to develop segmental kyphosis. Conclusions The design of the PEEK cage used may influence the SA, and this association needs to be considered when using stand-alone PEEK cages.

Retrospective cohort study of a nationwide database.The primary objective was to summarize the use of surgical methods for lumbar herniated intervertebral disc disease (HIVD) at two different time periods under the national health insurance system. The secondary objective was to perform a cost-effectiveness analysis by utilizing incremental cost-effectiveness ratio (ICER).The selection of surgical method for HIVD may or may not be consistent with cost effectiveness under national health insurance system, but this issue has rarely been analyzed.The data of all patients who underwent surgeries for HIVD in 2003 (n = 17,997) and 2008 (n = 38,264) were retrieved. The surgical methods included open discectomy (OD), fusion surgery, laminectomy, and percutaneous endoscopic lumbar discectomy (PELD). The hospitals were classified as tertiary-referral hospitals (≥300 beds), medium-sized hospitals (30-300 beds), or clinics (30 beds). ICER showed the difference in the mean total cost per 1% decrease in the reoperation probability among surgical methods. The total cost included the costs of the index surgery and the reoperation.In 2008, the number of surgeries increased by 2.13-fold. The number of hospitals increased by 34.75% (731 in 2003 and 985 in 2008). The proportion of medium-sized hospitals increased from 62.79% to 70.86%, but the proportion of surgeries performed at those hospitals increased from 61.31% to 85.08%. The probability of reoperation was highest after laminectomy (10.77%), followed by OD (10.50%), PELD (9.20%), and fusion surgery (7.56%). The ICERs indicated that PELD was a cost-effective surgical method. The proportion of OD increased from 71.21% to 84.12%, but that of PELD decreased from 16.68% to 4.57%.The choice of surgical method might not always be consistent with cost-effectiveness strategies, and a high proportion of medium-sized hospitals may be responsible for this change.4.

OBJECTIVEPedicle screw-rod–based hybrid stabilization (PH) and interspinous device–based hybrid stabilization (IH) have been proposed to prevent adjacent-segment degeneration (ASD) and their effectiveness has been reported. However, a comparative study based on sound biomechanical proof has not yet been reported. The aim of this study was to compare the biomechanical effects of IH and PH on the transition and adjacent segments.METHODSA validated finite element model of the normal lumbosacral spine was used. Based on the normal model, a rigid fusion model was immobilized at the L4–5 level by a rigid fixator. The DIAM or NFlex model was added on the L3–4 segment of the fusion model to construct the IH and PH models, respectively. The developed models simulated 4 different loading directions using the hybrid loading protocol.RESULTSCompared with the intact case, fusion on L4–5 produced 18.8%, 9.3%, 11.7%, and 13.7% increments in motion at L3–4 under flexion, extension, lateral bending, and axial rotation, respectively. Additional instrumentation at L3–4 (transition segment) in hybrid models reduced motion changes at this level. The IH model showed 8.4%, −33.9%, 6.9%, and 2.0% change in motion at the segment, whereas the PH model showed −30.4%, −26.7%, −23.0%, and 12.9%. At L2–3 (adjacent segment), the PH model showed 14.3%, 3.4%, 15.0%, and 0.8% of motion increment compared with the motion in the IH model. Both hybrid models showed decreased intradiscal pressure (IDP) at the transition segment compared with the fusion model, but the pressure at L2–3 (adjacent segment) increased in all loading directions except under extension.CONCLUSIONSBoth IH and PH models limited excessive motion and IDP at the transition segment compared with the fusion model. At the segment adjacent to the transition level, PH induced higher stress than IH model. Such differences may eventually influence the likelihood of ASD.

For patients with single-level cervical radiculopathy, various types of motion preservation surgeries, such as total disc replacement (TDR), posterior cervical foraminotomy (PCF) and posterior percutaneous endoscopic foraminotomy and discectomy (PECF), are available. In addition to motion preservation, the quality of motion is an important issue. The aim of the present study was to evaluate the influence of these surgeries on cervical motion by comparing the instantaneous axis of rotation (IAR) among PECF, TDR and PCF at the index and superior/inferior adjacent segments. A retrospective review was performed of patients who underwent index surgery at C5–6 for cervical single-level foraminal disc herniation or foraminal stenosis. Patients with minimal degeneration at the index and other cervical spinal levels and flexion/extension cervical lateral radiographs both preoperatively and 6 months postoperatively were included (PECF, 11 patients; TDR, 11 patients; PCF, 12 patients). The IARs were calculated at the index segment and segments above and below the index segment from the flexion and extension cervical lateral radiographs, which were obtained preoperatively and 6 months postoperatively. A standardized cervical normogram was referenced to qualify shifts in the IAR. Postoperatively, neck pain was significantly decreased, with no difference among the surgical methods. The IARs were not significantly changed after the PECF. Although significant inferior shift occurred at C6–7 after TDR (p = 0.02), the shift occurred within the normal range in the cervical normogram. However, significant inferior shifts in the IARs occurred after PCF at C5–6 (p = 0.02) and C6–7 (p = 0.02), and the IARs moved out of the normal range. The IARs were significantly changed after PCF at either the index segment or the adjacent segment below. The shifts in IAR at the index and adjacent segments were not significant after PECF and TDR. The sample size was too small to allow definitive conclusions, but the present study showed that PECF may be another alternative to motion preservation surgeries.

OBJECTIVEAs life expectancy continues to increase, primary degenerative sagittal imbalance (PDSI) is diagnosed in an increasing number of elderly people. Although corrective surgery for this sagittal deformity is becoming more popular, the effectiveness of the procedure remains unclear. The authors aimed to collate the available evidence on the effectiveness and complications of deformity-correction surgery in patients with PDSI.METHODSThe authors carried out a meta-analysis of clinical studies regarding deformity correction in patients with PDSI. The studies were identified through searches of the PubMed, Embase, Web of Science, and Cochrane databases. Surgery outcomes were evaluated and overall treatment effectiveness was assessed in terms of the minimum clinically important difference (MCID) in Oswestry Disability Index (ODI) values and pain levels according to visual analog scale (VAS) scores and in terms of restoration of spinopelvic parameters to within a normal range. Data are expressed as mean differences with 95% CIs.RESULTSTen studies comprising 327 patients were included. The VAS and ODI values improved after deformity-correction surgery. The smallest treatment effect exceeded the MCID for VAS values (4.15 [95% CI 3.48–4.82]) but not for ODI values (18.11 [95% CI 10.99–25.23]). At the final follow-up visit, the mean lumbar lordosis angle (−38.60° [95% CI −44.19° to −33.01°]), thoracic kyphosis angle (31.10° [95% CI 24.67°–37.53°]), C-7 sagittal vertical axis (65.00 mm [95% CI 35.27–94.72 mm]), and pelvic tilt angle (30.82° [95% CI 24.41°–37.23°]) remained outside their normal ranges. Meta-regression analyses revealed a significant effect of ODI change in relation to lumbar lordosis change (p = 0.004). After a mean of 2 years after deformity correction, the mean lumbar lordosis angle and C-7 sagittal vertical axis decreased by 5.82° and 38.91 mm, respectively, and the mean thoracic kyphosis angle increased by 4.7°. The incidences of proximal junctional kyphosis and pseudarthrosis were 23.7% and 12.8%, respectively.CONCLUSIONSDeformity correction substantially relieves back pain for about 2 years in adult patients with PDSI. Sufficient surgical restoration of lumbar lordosis can lead to substantial improvement in patient disability and reduced decompensation. Deformity correction represents a viable therapeutic option for patients with PDSI, but further technical advancements are necessary to achieve sufficient lumbar lordosis and reduce complication rates.

Herniated intervertebral disc disease (HIVD) is a common cause of lower back and leg pain. Percutaneous endoscopic lumbar discectomy (PELD) is indicated when non-surgical treatments such as medication and interventions are intractable. Ruptured discs and loose fragments inside discs are removed during PELD. Nerve root decompression is usually assessed by visualizing the free movement of the traversing nerve root or epidural fat, the free passage of a probe into the epidural space, the depression of the annulus, and the removal of the expected ruptured discs and loose fragments based on preoperative magnetic resonance images (MRI). However, these criteria are subjective, and the quantity of the disc removal necessary for successful outcomes after PELD has not been investigated.The present study investigates the amount of discectomy of PELD and its clinical and radiological outcomes.A retrospective case study (IRB Number H-1611-015-803).University Medical Center, Seoul, Korea.PELD was performed in 109 consecutive patients (M:F = 53:56; mean age, 37.4 years) using the transforaminal or interlaminar route. Ruptured disc fragments were first removed in all patients, and the graspable loose fragments under the disc were removed. After surgery, all removed disc fragments were placed into disposable syringes and manually compressed to measure their volume. The volume of herniated disc outside the disc boundary was calculated in MRI. The measured and calculated disc volumes were retrospectively compared. Clinical success was defined as an improvement in both the Oswestry Disability Index (ODI) and leg pain, as well as no recurrent symptoms. Radiological success was defined as the disappearance of herniated disc material outside the disc boundary based on postoperative MRI taken within one day after surgery. The follow-up period was 7.2 ± 5.2 months.Successful clinical outcomes were obtained in 96/109 (88.1%) patients in a median time of 3 months. Re-operation was performed in 3 patients due to recurrent discs in 2 patients and a residual disc in one patient. Predictors of clinical success were not identified, and the quantity of the removed disc was not associated with the clinical outcome. Radiological success was achieved in 93/109 (85.3%) patients. Of 13 patients with radiological failure, 2 patients showed clinical failure. A logistic regression analysis showed that the relative volume of the removed disc (%) compared with the volume of preoperative herniated disc based on the MRI was the only significant predictor (P0.001; OR = 0.96). When 100% of the calculated disc amount was removed during the operation, the probability of residual disc was 30%. When 131% of the calculated disc amount was removed, the probability of residual disc was 10%.This study employed a retrospective design, and its inherent selection bias and limited statistical power should be considered.The amount of disc removal during PELD was not a significant predictor of clinical success after the primary ruptured fragments were removed. The relative volume of the removed disc based on the preoperative MRI might predict the postoperative MRI.Disc, lumbar vertebra, discectomy, surgery, endoscopy, volume.

Objective The purpose of this study is to describe the detailed surgical technique and short-term clinical and radiological outcomes of lateral lumbar interbody fusion (LLIF) and in situ lateral screw fixation using a conventional minimally invasive screw fixation system (MISF) for revision surgery to treat rostral lumbar adjacent segment disease. Methods The medical and radiological records were retrospectively reviewed. The surgery was indicated in 10 consecutive patients with rostral adjacent segment stenosis and instability. After the insertion of the interbody cage, lateral screws were inserted into the cranial and caudal vertebra using the MISF through the same LLIF trajectory. The radiological and clinical outcomes were assessed preoperatively and at 1, 3, 6, and 12 months postoperatively. Results The median follow-up period was 13 months (range, 3–48 months). Transient sensory changes in the left anterior thigh occurred in 3 patients, and 1 patient experienced subjective weakness; however, these symptoms normalized within 1 week. Back and leg pain were significantly improved (p

The progression of cervical kyphosis due to injury to the facet joints and musculature is a major concern for posterior foraminotomy especially for patients with cervical lordosis of less than 10°. However, cervical hypo-lordosis (cervical lordosis10°) may be improved with the alleviation of pain and muscle spasms, which corresponds with the disappearance of a positive Spurling's test. When surgery is necessary, the spontaneous recovery of cervical curvature may be minimally offset using minimally invasive surgical techniques, such as posterior percutaneous endoscopic cervical foraminotomy (P-PECF).The primary objective was to compare the changes in cervical kinematics between patients with cervical lordosis (≥ 10°, group I) and hypo-lordosis (10°, group II) after P-PECF.This study was a retrospective nested case-control study with the IRB No. H-1210-078-434.University Medical Center, Seoul, Korea.P-PECFs were performed for patients with a radiculopathy due to single-level unilateral cervical foraminal soft-disc herniations or foraminal stenosis with minimal degeneration of the disc/facet joints and a positive Spurling's test. A retrospective nested case-control study was performed for 23 patients with cervical lordosis of ≥ 10° (group I; M:F = 15:8; age, 52.3 ± 9.8 years) and 23 patients with cervical lordosis of10°(group II; M:F = 15:8; age, 46.3 ± 12.7 years). P-PECFs were performed using the methods previously reported, and all patients were discharged the next day without limitations on neck motion. The patients were followed at one, 3, 6, and 12 months postoperatively and yearly thereafter. The follow-up period was 25.8 ± 19.6 months. Clinical outcomes were assessed using the visual analogue pain score of arms. The cervical angles (C2-7, tangential method) were measured on neutral (CA), flexion (CAF), and extension (CAE) lateral radiographs, and range of motion (C-ROM) was calculated by conducting a radiological analysis. A linear mixed model was used to assess the linearity of the changes in cervical curvatures during the postoperative 12 months between the groups.Significant reductions in arm pain and negative results on Spurling's test were initially achieved in 21/23 patients in group I and in 23/23 patients in group II with means of 1.7 ± 0.31 months and 1.09 ± 0.09 months, respectively. Using the mixed effect models, the interactions between group and time were significant for the CA (P = 0.004), CAE (P0.001), and C-ROM (P0.001) but not the CAF (P = 0.392). The CA (adjusted-P0.001), CAE (adjusted-P0.001), and C-ROM (adjusted-P = 0.046) exhibited significant between-group differences at the pre-operation. However, during the follow-up, these parameters were significantly changed in group II, especially during the postoperative 3 months. The CA, CAE, and C-ROM changed by -11.73°, -19.87°, and 20.32°, respectively. Postoperatively, 17/23 patients in group II and 22/23 patients in group I exhibited cervical lordosis of ≥ 10°.This study was retrospective in design, and the inherent selection bias and limited statistical power should be considered.Cervical hypo-lordosis less than 10° may not be a contra-indication for P-PECF when the change of cervical curvature is not a structural change. A larger study is necessary to identify prognostic factors. Key words: Alignment, cervical vertebrae, disc, percutaneous, endoscopes, biomechanical phenomena, surgery, lordosis, kyphosis.

Seizure is the most common presentation in patients with cerebral cavernous malformations (CCMs). Although many articles have documented seizure outcomes after resection of CCM, few have conducted long-term follow-ups; thus, the fluctuating seizure outcomes have been neglected. The purpose of this study is to describe long-term postoperative seizure outcomes in patients with CCM and to compare seizure outcomes between patients with sporadic seizures and those with chronic seizures. Forty-six patients with CCM presenting with seizures underwent surgery. The male-to-female ratio was 1:1, and the average age at initial seizure onset was 27.6 years. The mean preoperative seizure duration was 42.7 months. Patients were divided into two groups: a chronic group (N = 20) and a sporadic group (N = 26) according to seizure frequency and duration. The mean postoperative follow-up duration was 96.3 months, and the postoperative seizure outcomes were checked annually based upon Engel’s classification. After the first year of follow-up, 80.8 % of the sporadic group and 75.0 % of the chronic group were evaluated as Engel class I. These rates increased to 100.0 % and 90.0 %, respectively, at the eighth year of follow-up. Overall, 29 (63.0 %) of the 46 patients experienced changes in seizure outcomes over the follow-up period. Despite their delayed improvements, the chronic group showed less favorable outcomes throughout follow-up (p = 0.025). Long-term follow-up is indispensable for accurately assessing postoperative seizure outcomes because these outcomes change continuously. We recommend earlier surgery to achieve seizure-free status in patients with CCM. However, even in the chronic group, surgery is recommended, considering the overall delayed improvement.

Traumatic cervical spinal cord injuries (SCIs) frequently develop dural tears and resultant cerebrospinal fluid (CSF) leaks. They are not usually identified with advanced imaging, and there are no reports on managing CSF leaks after cervical trauma. Hence, the authors evaluated the incidence of CSF leaks after cervical SCIs and described how to predict and manage CSF leaks. An observational retrospective study was done confirming intraoperative CSF leaks among 53 patients with anterior cervical surgery after cervical spine trauma between 2004 and 2011. Seven patients (13.2 %) had dural tears and resultant CSF leaks intraoperatively (M:F ratio of 6:1; mean age, 44.7 years). An initial poor American Spinal Injury Association (ASIA) scale was significantly associated with CSF leaks (p = 0.009). From magnetic resonance imaging (MRI), disruption of the ligamentum flavum was correlated with CSF leaks (p = 0.02). Intraoperative application of fibrin glue on the operated site, postoperative management through the early removal of the wound drain within the first 24 h and early rehabilitation were performed in patients with CSF leaks without perioperative insertion of a lumbar drain. During the follow-up period, none of the patients developed CSF-leak-related complications. The incidence of CSF leaks after traumatic cervical SCI is relatively higher than that of degenerative cervical spinal surgery. An initial poor neurological status and disruption of the ligamentum flavum on the MRI in patients were predictable factors of dural tears and CSF leaks.

Cervical spondylotic myelopathy (CSM) may be caused by static and dynamic spinal cord compression, particularly during neck extension. Dynamic compression may be better evaluated with dynamic magnetic resonance (MR) images. We performed a retrospective study to determine the clinical indication for dynamic MR imaging, and conducted a survey regarding image interpretation by clinicians.A total of 32 patients (M:F = 20:12, 60.1 ± 10.7 years) who had undergone neutral/extension cervical MR imaging were included. The study population consisted of 22 patients with signs of cervical myelopathy (M group) and 10 patients without signs of myelopathy (NM group). The number of compression levels (complete obliteration of the anterior and posterior subarachnoid space) was assessed at each level in mid-sagittal, T2-weighted, neutral and extension MR images. Reproduced images from 22 patients in the M group were randomly arranged, and four experienced spine surgeons at four different institutes interpreted them to reach a clinicians' agreement. The agreements were then assessed with inter-rater correlation coefficients (ICC).Analysis with extension MR images found an increased number of compression levels in 23/32 (72 %) of patients; 20/22 in the M group and 3/10 in the NM group (p 0.01, chi-squared test), as compared to findings of the neutral MR images. Clinical factors for increased compression levels in extension MR images were age (p 0.01, 63.3 ± 10.0 years vs. 51.9 ± 8.1) and signs of myelopathy (p 0.01, odds ratio, 23.33). Clinician agreement was improved with extension MR images; ICC was 0.67 with neutral and 0.81 with extension MR images.The evaluation of CSM may be improved with dynamic MR images. Dynamic MR scanning may be considered for elderly patients with signs of myelopathy, but an interpretation for asymptomatic spinal compression based exclusively on extension MR image should be made with caution.

Background context Lumbar spinal stenosis is one of the most common degenerative spine diseases. Surgical options are largely divided into decompression only and decompression with arthrodesis. Recent randomized trials showed that surgery was more effective than nonoperative treatment for carefully selected patients with lumbar stenosis. However, some patients require reoperation because of complications, failure of bony fusion, persistent pain, or progressive degenerative changes, such as adjacent segment disease. In a previous population-based study, the 10-year reoperation rate was 17%, and fusion surgery was performed in 10% of patients. Recently, the lumbar fusion surgery rate has doubled, and a substantial portion of the reoperations are associated with a fusion procedure. With the change in surgical trends, the longitudinal surgical outcomes of these trends need to be reevaluated. Purpose To provide the longitudinal reoperation rate after surgery for spinal stenosis and to compare the reoperation rates between decompression and fusion surgeries. Study design/setting Retrospective cohort study using national health insurance data. Patient sample A cohort of patients who underwent initial surgery for lumbar stenosis without spondylolisthesis in 2003. Outcome measures The primary end point was any type of second lumbar surgery. Cox proportional hazards regression modeling was used to compare the adjusted reoperation rates between decompression and fusion surgeries. Methods A national health insurance database was used to identify a cohort of patients who underwent an initial surgery for lumbar stenosis without spondylolisthesis in 2003; a total of 11,027 patients were selected. Individual patients were followed for at least 5 years through their encrypted unique resident registration number. After adjusting for confounding factors, the reoperation rates for decompression and fusion surgery were compared. Results Fusion surgery was performed in 20% of patients. The cumulative reoperation rate was 4.7% at 3 months, 7.2% at 1 year, 9.4% at 2 years, 11.2% at 3 years, 12.5% at 4 years, and 14.2% at 5 years. The adjusted reoperation rate was not different between decompression and fusion surgeries (p=.82). The calculated reoperation rate was expected to be 22.9% at 10 years. Conclusions The reoperation rate was not different between decompression and fusion surgeries. With current surgical trends, the reoperation rate appeared to be higher than in the past, and consideration of this problem is required.

Background There may be patients with spinal metastasis for whom neither vertebroplasty/kyphoplasty nor open surgery is appropriate. Percutaneous pedicle screw fixation (PPSF) may fill the gap between techniques. Objectives To assess the outcome of the PPSF and radiotherapy/chemotherapy. Methods PPSF was performed for 16 patients (mean age, 57 ± 12 years) with pathologic fractures, Tomita score ≥5, 3–6 months of life expectancy, minimal epidural tumor extension and a Nurick grade better than 3. PPSF was performed under general anesthesia. Collapsed vertebra(e) was restored during assembly of contoured rod. Vertebroplasty was then performed for 14 patients at the restored vertebra(e). The Eastern Cooperative Oncology Group (ECOG) performance status grade was 2 in seven patients and 3 in nine. The numerical rating pain score (NRS) was 8.2 ± 1.8. The follow-up was 261 ± 193 days. Results All patients walked home at postoperative day 4–7. Radiotherapy and chemotherapy was performed for 8 and 10 patients, respectively. ECOG was improved or stationary in 13/16 (81%) at 1-month and improved in 6/6 of alive patients at the last follow-up. NRS was 3.8 ± 2.0. The median ambulation and survival times were 207 and 222 days. Conclusion Using a multidisciplinary approach, quality of life can be improved for fragile patients with spinal metastasis. J. Surg. Oncol. 2013; 108:499–503. © 2013 Wiley Periodicals, Inc.

Object Spinal vascular diseases, such as spinal dural arteriovenous fistulas (DAVFs), perimedullary arteriovenous fistulas (AVFs), and spinal arteriovenous malformations (AVMs), are very rare. The authors analyzed the features and treatment outcomes of these conditions. Methods Data from 64 patients were retrospectively reviewed. There were 33 spinal DAVFs (1 patient had 2 lesions), 20 perimedullary AVFs, and 12 spinal AVMs. Clinical features, radiological findings, treatment results, and clinical outcomes were evaluated according to the diseases, subtypes, and treatment modalities. The median duration of follow-up was 20, 42, and 56 months for spinal DAVFs, perimedullary AVFs, and spinal AVMs, respectively. Results Spinal DAVFs showed faster progression of symptoms (median 5, 12, and 36 months for spinal DAVFs, perimedullary AVFs, and spinal AVMs, respectively) and worse neurological status at diagnosis (poor neurological status in 56%, 65%, and 33%, respectively). On MRI, signal voids were demonstrated in all except 1 spinal DAVF. At the last follow-up, 94% of spinal DAVFs, 68% of perimedullary AVFs, and 50% of spinal AVMs were completely obliterated. Favorable clinical outcomes were achieved in 91%, 95%, and 58%, respectively. In detail, the majority (78%) of spinal DAVFs were embolized, resulting in complete obliteration in 92% and favorable clinical outcomes in 92%. Most Type IVa and IVb perimedullary AVFs were surgically treated (71% and 88%), with complete obliterations of 86% and 71%, and favorable clinical outcomes in 100% and 86%, respectively. All Type IVc lesions were embolized with a low cure rate of 40%; however, clinical outcomes were satisfactory. Spinal AVMs were generally embolized (67%), and only glomus-type lesions attained a satisfactory cure rate (80%) and clinical outcome (100%). Conclusions Embolization produced satisfactory outcomes in spinal DAVFs and glomus-type spinal AVMs. Surgery is advantageous in Type IVa and IVb perimedullary AVFs. Palliative embolization can be effective in Type IVc perimedullary AVFs and juvenile spinal AVMs.

Object Supplementary motor area (SMA) resection often induces postoperative contralateral hemiparesis or speech disturbance. This study was performed to assess the neurological impairments that often follow SMA resection and to assess the risk factors associated with these postoperative deficits. Methods The records for patients who had undergone SMA resection for pharmacologically intractable epilepsy between 1994 and 2010 were gleaned from an epilepsy surgery database and retrospectively reviewed in this study. Results Forty-three patients with pharmacologically intractable epilepsy underwent SMA resection with intraoperative cortical stimulation and mapping while under awake anesthesia. The mean patient age was 31.7 years (range 15–63 years), and the mean duration and frequency of seizures were 10.4 years (range 0.1–30 years) and 14.6 per month (range 0.1–150 per month), respectively. Pathological examination of the brain revealed cortical dysplasia in 18 patients (41.9%), tumors in 16 patients (37.2%), and other lesions in 9 patients (20.9%). The mean duration of the follow-up period was 84.0 months (range 24–169 months). After SMA resection, 23 patients (53.5%) experienced neurological deficits. Three patients (7.0%) experienced permanent deficits, and 20 (46.5%) experienced symptoms that were transient. All permanent deficits involved contralateral weakness, whereas the transient symptoms patients experienced were varied, including contralateral weaknesses in 15, apraxia in 1, sensory disturbances in 1, and dysphasia in 6. Thirteen patients recovered completely within 1 month. Univariate analysis revealed that resection of the SMA proper, a shorter lifetime seizure history (< 10 years), and resection of the cingulate gyrus in addition to the SMA were associated with the development of neurological deficits (p = 0.078, 0.069, and 0.023, respectively). Cingulate gyrus resection was the only risk factor identified on multivariate analysis (p = 0.027, OR 6.530, 95% CI 1.234–34.562). Conclusions Resection of the cingulate gyrus in addition to the SMA was significantly associated with the development of postoperative neurological impairment.

Objectives:The aim of this study was to systematically assess the long-term (≥ 6 months) benefits of epidural steroid injection therapies for patients with low back pain.Methods:We identified randomized controlled trials by database searches up to October 2011 and by additional hand searches without language restrictions. Randomized controlled trials on the effects of epidurals for low back pain with follow-up for at least 6 months were included. Outcomes considered were pain relief, functional improvement in 6 to 12 months after epidural steroid injection treatment and the number of patients who underwent subsequent surgery. Meta-analysis was performed using a random-effects model.Results:Twenty-nine articles were selected. The meta-analysis suggested that a significant treatment effect on pain was noted at 6 months of follow-up (weighted mean difference [WMD], −0.41; 95 percent confidence interval [CI], −0.66 to −0.16), but was no longer statistically significant after adjusting for the baseline pain score (WMD, −0.19; 95 percent CI, −0.61 to 0.24). Epidural steroid injection did not improve back-specific disability more than a placebo or other procedure. Epidural steroid injection did not significantly decrease the number of patients who underwent subsequent surgery compared with a placebo or other treatments (relative risk, 1.02; 95 percent CI, 0.83 to 1.24).Conclusions:A long-term benefit of epidural steroid injections for low back pain was not suggested at 6 months or longer. Introduction of selection bias in the majority of injection studies seems apparent. Baseline adjustment is essential when we evaluate pain as a main outcome of injection therapy.

There have been numerous studies on the outcomes of surgery for spinal cord cavernous angiomas. However, the natural history of conservatively treated disease is not well known. The aim of this retrospective study was to investigate the outcomes of conservatively managed patients with spinal cord cavernous angioma to determine the appropriate treatment strategies.Twenty-four patients who visited a single institution over an 11-year period and who were treated conservatively were enrolled in this study. Their medical records and radiological images were reviewed retrospectively. The neurologic status of the patients was assessed using the Japanese Orthopedic Association scoring system and the clinical presentation of the patients was classified into the following 4 categories: type A, asymptomatic; B, pain only; C, sensory deficits; and D, sensory and motor deficits. The results of types C and D patients were compared with the results of previously reported surgical series from our institution.The mean age of the enrolled patients was 52.0 years (21-73). The mean duration of the clinical follow-up was 60.5 months (11-119) and the follow-up using magnetic resonance imaging was 52.4 months (3-122). Cavernous angiomas presented in the cervical spinal cord in 12 patients, thoracic spinal cord in 10 patients and in multiple levels of the spinal cord in 2 patients. There were 5, 5, 7, and 7 patients, respectively, classified with types A, B, C, and D for clinical presentations. The rate of recurrent hemorrhage was 1.7 %/patient-year and all recurrent hemorrhages only developed in type C or D patients. In types C and D patients, improvement in the JOA score during the follow-up period was 0.77 ± 1.8 in the conservative group and 1.07 ± 1.8 in the surgical group (p = 0.500). However, improvement in the JOA sensory score after surgical treatment was statistically significant (P = 0.007).Conservative treatment may be a reasonable treatment strategy for patients with types A and B. If patients present with type C or D, surgical treatment is recommended considering the better improvements in sensory deficits and the high rate of recurrent hemorrhage in such patients.

Department of Neurosurgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul(S.-H.L., E.-S.K., W.E.); Department of Neurosurgery, Seoul National University College of Medicine, Seoul(C.K.C., C.H.K.); Department of Neurosurgery, Seoul National University Bundang Hospital, Seongnam, SouthKorea (S.H.Y., S.-J.H., K.-J.K., H.-J.K.)Background. We sought to determine the surgical treat-ment and functionaloutcome andidentify the predictorsof survival in a retrospective cohort of patients withspinal cord ependymoma using data collected from theKorea Spinal Oncology Research Group database.Methods. The data regarding 88 patients who had beensurgically treated for histologically confirmed spinalcord intramedullary and extramedullary ependymomafrom January 1989 to December 2009 were retrospec-tively reviewed.Results. Histopathological examination revealed myxo-papillary ependymoma in 24 patients, ependymoma in61 patients, and anaplastic ependymoma in 3 patients.Gross total removal was achieved in 72 patients, subto-tal removal in 15 patients, and partial removal in 1patient.Twenty patientsweretreatedwithpostoperativeradiation. Fifty-two patients had stable or improvedpostoperative neurological function, while 36 experi-enced neurological deterioration. A permanent decreasein McCormick classification grade was seen in 17 pa-tients. The progression-free survival rate was 87% forall patients at 5 years and 80% at 10 years. Duringfollow-up, local recurrence/progression was seen in13 patients. Diffuse meningeal spread developed in 2anaplastic ependymoma patients. Postoperative radio-therapy after incomplete resection did not significantlycorrelate with longer times to recurrence. Multivariateanalysis revealed histology and surgical extent of resec-tion as independent predictors of longer progression-free survival.Conclusions. Gross total removal alone is a good treat-ment strategy for spinal ependymomas. Early diagnosisand surgery, before severe paralysis, are important toobtain good functional outcomes. Subtotal resection withradiation therapy for intramedullary lesions appears tooffernoadvantagesovergrosstotalremoval.Keywords: myxopapillary ependymoma, radiation, spinalependymoma, survival.

BACKGROUND Anterior cervical discectomy and fusion (ACDF) with autologous iliac bone graft and plating has been a standard surgical method for single-level cervical disc disease. The stand-alone cage was introduced to reduce graft-related morbidity. However, problems due to focal kyphosis at the operated level have been on the rise. It has been difficult to derive a conclusive answer from previous studies for the indications of each method. OBJECTIVE An interim analysis of a prospective randomized study was performed to compare the sagittal alignment between a stand-alone cage (ACDF cage) and autologous iliac bone graft and plating (ACDF plate). METHODS Twenty-nine patients were allocated to the ACDF-cage group (M:F = 17:12) and 23 to the ACDF-plate group (M:F = 14:9). Cobb angles at the operated segment (segmental angle, SA; lordosis vs kyphosis) were compared at postoperative 12 months and the other confounding factors were explored. RESULTS Demographic features were not different between groups. The fusion method significantly affected segmental alignment at 12 months (P = .03; odds ratio, 5.52). Preoperatively, the SA was not different between the groups (P = .18) and was similar (P = .22) immediately following the operation. However, the SA was significantly more lordotic (P < .05) in the ACDF-plate group at postoperative 12 months in comparison with the ACDF-cage group. There was no other significant risk factor for segmental kyphosis. CONCLUSION The stand-alone cage and autologous bone graft with plating had similar clinical outcomes, but stand-alone cage fusion may be disadvantageous from a radiological viewpoint.

Background Anterior cervical fusion (ACF) with autologous iliac bone graft is a traditional surgical method, but high rate of chronic pain (30%) at the anterior iliac crest presents a considerable hindrance to harvesting iliac bone. The memory of acute pain may become fainter as time progresses, and the incidence of chronic pain may not be as high as previously reported. The primary objective was to show the patient-reported outcome of chronic pain in the anterior iliac crest. Methods Telephone surveys were conducted for patients with single-level ACF (group-S; n = 72; M:F = 52:20; median age, 53 years), multiple-level ACF (group-M; n = 61; M:F = 40:21; 56 years) using autologous iliac bone, and single-level ACF with a stand-alone cage (group-C; n = 53; M:F = 38:15; 51 years). Logistic regression analysis was performed to determine the risk factors, and the variables included group, age, gender, postoperative period and satisfaction with the surgical outcome. Results There was no chronic pain in 87% of the patients, with no difference among the groups ( p = 0.52). During the acute postoperative period, patients remembered no pain in 38/72 (53%) patients of group-S, 25/61 (41%) of group-M and 42/53 (79%) of group-C ( p p = 0.027; OR, 2.68; 95% CI, 1.12–6.41) was the risk factor for chronic pain. Conclusions Iliac bone harvest may not cause chronic pain in 87% of patients, and the memory of acute pain was faded in 40–50% of patients. Female gender was a risk factor for chronic pain. This information should be considered before harvesting iliac bone.

Objective To identify and investigate differences in spinal fusion between the normal and osteopenic spine in a rat model. Methods Female Sprague Dawley rats underwent either an ovariectomy (OVX) or sham operation and were randomized into two groups: non-OVX group and OVX group. Eight weeks after OVX, unilateral lumbar spinal fusion was performed using autologous iliac bone. Bone density (BD) was measured 2 days and 8 weeks after fusion surgery. Microcomputed tomography was used to evaluate the process of bone fusion every two weeks for 8 weeks after fusion surgery. The fusion rate, fusion process, and bone volume parameters of fusion bed were compared between the two groups. Results BD was significantly higher in the non-OVX group than in the OVX group 2 days and 8 weeks after fusion surgery. The fusion rate in the non-OVX group was higher than that in the OVX group 8 weeks after surgery (p=0.044). The bony connection of bone fragments with transverse processes and bone formation between transverse processes in non-OVX group were significantly superior to those of OVX group from 6 weeks after fusion surgery. The compactness and bone maturation of fusion bed in non-OVX were prominent compared with the non-OVX group. Conclusion The fusion rate in OVX group was inferior to non-OVX group at late stage after fusion surgery. Bone maturation of fusion bed in the OVX group was inferior compared with the non-OVX group. Fusion enhancement strategies at early stage may be needed to patients with osteoporosis who need spine fusion surgery.

Objective: This study is to estimate the diagnostic accuracy of Tokuhashi and Tomita scores that assures 6-month predicting survival regarded as a standard of surgical treatment. Method: We searched PubMed, EMBASE, European PubMed central, and the Cochrane library for papers about the sensitivities[for full text, please go to the a.m. URL], 67. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), 1. Joint Meeting mit der Koreanischen Gesellschaft für Neurochirurgie (KNS)