Changes in Parameters after High Tibial Osteotomy: Comparison of EOS System and Computed Tomographic Analysis.

Unintended rotation of the distal tibia occurs during medial open-wedge high tibial osteotomy (MOWHTO). Computed tomography (CT) is the standard method of measuring lower limb alignment; however, the new low-dose EOS system allows three-dimensional limb modeling with automated measurements of lower limb alignment. This study investigated the differences between the changes in lower limb alignment profiles obtained using the EOS system and CT in patients who underwent MOWHTO. We investigated whether any factors contributed to the degree of deformation. Thirty patients were prospectively enrolled between October 2019 and February 2023. Changes in femoral and tibial torsion, femorotibial rotation, and posterior tibial slope were measured using pre- and post-MOWHTO CT and EOS images. We found no significant difference in pre- and postoperative tibial torsion or posterior tibial slope between CT and EOS. No variables showed a significant correlation with changes in the tibial torsion or posterior tibial slope. This study confirmed the possibility that the EOS system could replace CT in measuring changes in several parameters pre- and postoperatively. Furthermore, we confirmed that the distal tibia tended to be internally rotated after MOWHTO; however, we found no significantly related parameters related to deformation caused by MOWHTO.

Effects of an Eye-Tracking Linkage Attention Training System on Cognitive Function Compared to Conventional Computerized Cognitive Training System in Patients with Stroke.

Objective: The purpose of the study was to investigate the effects of an eye-tracking linkage attention training system on cognitive function compared to a conventional computerized cognitive training system in stroke patients with cognitive impairment. Methods: This retrospective study was enrolled 40 stroke patients who received cognitive rehabilitation. The intervention consisted of 30 sessions and 30 min per session. Before and after the intervention, we assessed cognitive functions by Mini-Mental State Examination (MMSE-K) and activities of daily living by Modified Barthel Index (K-MBI) and administered a computerized neuropsychological test (CNT). Results: In both groups, there were significant improvements in MMSE-K and K-MBI (p < 0.05). In the visual and auditory attention test of the CNT, the eye-tracking linkage attention training group was significantly improved after intervention (p < 0.05). However, there were no significant differences in the conventional computerized cognitive training group. In addition, there were significant improvements in all memory tests of the CNT in the eye-tracking linkage attention training group. However, in the conventional computerized cognitive training group, there were significant improvements in some memory tests of the CNT. Conclusions: The training of poststroke cognitive impairment patients using an eye-tracking linkage attention training system may improve visuospatial attention and may be helpful for the improvement of short-term memory and independent performances in daily life activities.

A Scalable Implementation of Anonymous Voting over Ethereum Blockchain.

We considered scalable anonymous voting on the Ethereum blockchain. We identified three major bottlenecks in implementation: (1) division overflow in encryption of voting values for anonymity; (2) large time complexity in tallying, which limited scalability in the number of candidates and voters; and (3) tallying failure due to "no votes" from registered voters. Previous schemes failed at tallying if one (or more) registered voters did not send encrypted voting values. Algorithmic solutions and implementation details are provided. An experiment using Truffle and Remix running on a desktop PC was performed for evaluation. Our scheme shows great reduction in gas, which measures the computational burden of smart contracts to be executed on Ethereum. For instance, our scheme consumed 1/53 of the gas compared to a state-of-the-art solution for 60 voters. Time complexity analysis shows that our scheme is asymptotically superior to known solutions. In addition, we propose a solution to the tallying failure due to the "no vote" from registered voters.

Unexpected Intradural Lumbar Disk Herniation Found During Transforaminal Endoscopic Surgery.

BACKGROUND: Intradural disk herniation (IDH) is defined as the displacement of the intervertebral disk nucleus pulposus into the dural sac. In this lumbar lesion, the affected level differs from that of a traditional extradural herniation: 55% of cases occur at the level of L4-5, 16% at L3-4, and 10% at L5-S1. Upper lumbar IDH is extremely rare. We present a case of an IDH at the level of L2-3 that was diagnosed during endoscopic surgery. CASE DESCRIPTION: A 65-year-old male patient presented with severe radiating pain in the anterior right thigh that was accompanied by a tingling sensation in the right calf and difficulty in walking. Physical examination showed normal strength. Bladder and bowel function was normal, but mild hypesthesia of the L3 sensory dermatome was observed. Magnetic resonance imaging revealed a herniated disk at the level of L2-L3 that was compressing the right side of the dura. A percutaneous transforaminal endoscopic lumbar diskectomy was planned. After foraminoplasty, no ruptured disk fragments could be found. During dissection of the adhesion between the dura and protruded disk, the dura was torn. Interestingly, through this dural opening, multiple fragmented disk portions were visualized among the nerve rootlets. We removed some of the soft disk material; however, complete removal of the disk fragments was predicted to damage the rootlets, and we decided to convert to microscopic surgery. The disk fragments were successfully removed via durotomy under microscopic assistance. The incised dorsal dura was primarily sutured with continuous stitches, and the defect on the ventrolateral side of the dura was patched and sealed using a harvested inner ligamentum flavum and Gelfoam (Pfizer, New York, New York, USA). After the operation, the patient's symptoms improved. There was no cerebrospinal fluid leakage. CONCLUSIONS: If there is any preoperative clinical or radiologic suspicion of IDH, a microscopic surgical approach should be considered to be the first-line option, as this is a safe and effective method for achieving IDH removal and dura repair without a postoperative neurologic deficit. Even during endoscopic surgery, if the surgeon expects even minor complications, we suggest converting to open surgery. In addition, the adequate sealing of the dura may be sufficient to prevent cerebrospinal fluid leakage, without the need for dural suture and lumbar drainage.

Effects of a Mixed Reality-based Cognitive Training System Compared to a Conventional Computer-assisted Cognitive Training System on Mild Cognitive Impairment: A Pilot Study.

BACKGROUND: Mixed reality (MR) technology, which combines the best features of augmented reality and virtual reality, has recently emerged as a promising tool in cognitive rehabilitation therapy. OBJECTIVE: To investigate the effectiveness of an MR-based cognitive training system for individuals with mild cognitive impairment (MCI). METHODS: Twenty-one individuals aged 65 years and older who had been diagnosed with MCI were recruited for this study and were divided into two groups. Participants in the MR group (n=10, aged 70.5±4.2 years) received 30 minutes of training 3 times a week for 6 weeks using a newly developed MR-based cognitive training system. Participants in the control group (n=11, aged 72.6±5.3 years) received the same amount of training using a conventional computer-assisted cognitive training system. Both groups took the Korean version of the Consortium to Establish a Registry for Alzheimer's Disease (CERAD-K) both before and after intervention. To determine the effect of the intervention on cognitive function, we compared the difference in each group's CERAD-K scores. RESULTS: There was a statistically significant interaction between intervention (MR group vs control group) and time (before vs after intervention) as assessed by the Constructional Recall Test. The individuals with MCI who participated in the MR training showed significantly improved performance in visuospatial working memory compared with the individuals with MCI who participated in the conventional training. CONCLUSION: An MR-based cognitive training system can be used as a cognitive training tool to improve visuospatial working memory in individuals with MCI.

Effect of three-dimensional spine stabilization exercise on trunk muscle strength and gait ability in chronic stroke patients: A randomized controlled trial.

BACKGROUND: Three-dimensional spine stabilization exercise can strengthen the trunk muscles with minimal spine movement. OBJECTIVE: To investigate the effects of the newly developed Spine Balance three-dimensional (3D) system on trunk strength and gait abilities of chronic stroke patients. METHODS: Twenty-four chronic stroke patients were randomly assigned to an experimental (n = 12) or control group (n = 12). The experimental and control groups performed spine stabilization exercise by using the newly developed Spine Balance 3D system and the well-known Bridge exercise thrice a week for 30 min per day for 7 weeks. Timed up and go (TUG) test, 10-m walking test (10-m WT), trunk muscle strength, and gait ability were evaluated before and after 7 weeks of intervention. RESULTS: The 10-m WT, TUG, walking speed, non-affected side step length, and distance in the experimental group, wherein trunk muscle strength was checked by using the Spine Balance 3D system evaluation program, showed more significant improvement than those in the control group (p < 0.05). CONCLUSION: We suggest that the newly developed Spine Balance 3D system can be a more useful therapeutic tool for rehabilitation of trunk muscle strength and gait abilities than bridge exercise-based spine stabilization exercise in chronic stroke patients.

Effects of visual fatigue caused by smartphones on balance function in healthy adults.

[Purpose] The purpose of this study was to determine the effects of visual fatigue caused by smartphone use on balance function. [Subjects and Methods] The participants consisted of 22 healthy male and female adults. Their postural stability, limit of stability, and limit of stability running time were evaluated using a computerized posturography apparatus before and after inducing visual fatigue. Postural stability and the limit of stability were divided into static and dynamic conditions. [Results] There were significant differences between the dynamic postural stability, the static and dynamic limit of stability, and both the static and dynamic limit of stability running times after the induction of visual fatigue. [Conclusion] The results showed that visual fatigue caused by smartphone use has a negative effect on balance function. Therefore, reducing visual fatigue through proper rest is necessary.

Relationship between dynamic balance and spatiotemporal gait symmetry in hemiplegic patients with chronic stroke.

BACKGROUND: Poor dynamic balance, which is common after stroke, may affect gait function. In particular, spatiotemporal asymmetrical gait patterns may occur in hemiplegic patients after stroke. OBJECTIVE: This study aimed to assess the relationship between dynamic balance and spatiotemporal gait symmetry in patients with chronic hemiplegic stroke. METHODS: To calculate symmetry ratios for step length (spatial parameter) and swing time (temporal parameter), 41 patients with chronic stroke walked at a comfortable speed. The dynamic balance measures included limit of stability (LOS) during standing and heel-to-heel base of support (H-H BOS) during gait. Analysis of correlations between various measures was performed. RESULTS: The overall LOS score correlated with temporal gait symmetry (r = 0.66). The forward, backward, paretic, and non-paretic direction LOS scores were related to temporal gait symmetry (r = 0.38-0.62). The H-H BOS was correlated with temporal (r = -0.63) and spatial (r = -0.36) gait symmetries. Other dynamic balance variables were not significantly correlated with spatial gait symmetry. CONCLUSION: Thus, control of dynamic balance abilities is related to the magnitude of temporal gait symmetry. This observation suggests that rehabilitation strategies that improve dynamic balance may enhance temporal gait symmetry in post-stroke patients.

Complementary value of pre-treatment apparent diffusion coefficient in rectal cancer for predicting tumor recurrence.

PURPOSE: To assess the complementary prognostic value of pre-treatment tumor apparent diffusion coefficient (ADC) for the prediction of tumor recurrence in patients with rectal cancer. METHODS: From March 2012 to March 2013, a total of 128 patients with mid/lower rectal cancer who underwent pre-treatment rectal MRI were enrolled in this retrospective study. Two radiologists in consensus evaluated conventional imaging features (Cimg) in pre-treatment rectal MRI: tumor height from anal verge (≤5 cm vs. >5 cm), T stage (high vs. low), the presence or absence of lymph node metastasis, mesorectal fascia invasion, and extramural venous invasion. The mean tumor ADC values (TumorADC) based on high b-value (0, 1000 × 10(-3) mm(2)/s) diffusion weight images were extracted. A multivariate Cox proportional hazard (CPH) regression was performed to evaluate the association of Cimg and TumorADC with the 3-year local recurrence (LR) rate. Predictive performance of two multivariate CPH models (Cimg only vs. Cimg + TumorADC) was compared using Harrell's c index (HCI). RESULTS: TumorADC (Adjusted HR, 7.830; 95% CI 3.937-15.571) and high T stage (Adjusted HR, 8.039; 95% CI 2.405-26.874) were independently associated with the 3-year LR rate. The CPH model generated with T stage + TumorADC (HCI, 0.820; 95% CI 0.708-0.932) showed significantly higher HCI than that with T stage only (HCI, 0.742; 95% CI 0.594-0.889) (P = 0.009). CONCLUSIONS: In patients with mid/lower rectal cancer, integrating TumorADC to Cimg increases predictive performance of the CPH model than that with Cimg alone for the prediction of LR within 3 years after surgery.

Effects of 3-Dimensional Lumbar Stabilization Training for Balance in Chronic Hemiplegic Stroke Patients: A Randomized Controlled Trial.

OBJECTIVE: To investigate the effects of the newly developed Spine Balance 3D system on the balance and gait abilities of hemiplegic stroke patients. METHODS: Twenty-eight hemiplegic patients with chronic stroke were randomly assigned to an experimental (n=14) or control group (n=14). The experimental and control groups performed balance training by using the newly developed Spine Balance 3D system and the well-known Biodex Balance System 30 minutes per day, three times a week for 7 weeks. The Berg Balance Scale (BBS), 10-m walking test (10mWT), Timed Up and Go Test (TUG), Functional Reach Test (FRT), the Korean version of the Fall Efficacy Scale-International (KFES-I), trunk muscle strength and stability were evaluated before and after 7 weeks of intervention. RESULTS: The 10mWT improved significantly (p=0.001) in the experimental group (using the Spine Balance 3D system) but not in the control group, and core muscle strength, which we checked using Spine Balance 3D system evaluation program, improved more in the experimental group as well. The results of the BBS, FRT, TUG, KFES-I, and Biodex Balance System evaluation program improved in both groups after 7 weeks of balance training. CONCLUSION: We suggest that the newly-developed Spine Balance 3D system can be a more useful therapeutic tool for gait and dynamic balance rehabilitation in hemiplegic patients than a conventional 2D-based balance training system. A large-scale randomized controlled study is needed to prove the effect of this system.

Effects of treadmill training with the eyes closed on gait and balance ability of chronic stroke patients.

[Purpose] The purpose of this study was to compare the effect of treadmill walking with the eyes closed and open on the gait and balance abilities of chronic stroke patients. [Subjects and Methods] Thirty patients with chronic stroke participated in this study. The treadmill gait training for each group lasted 40 minutes, and sessions were held 3 times a week for 4 weeks. Gait ability was measured using a Biodex Gait Trainer Treadmill System. Balance ability was measured using a Biodex Balance System. [Results] After the treadmill training' the treadmill training with eyes closed (TEC) group showed significant improvements in walking distance' step length' coefficient of variation' and limit of stability (overall' lateral affected' forward lateral unaffected) compared to the treadmill training with eyes open (TEO) group. [Conclusion] The walking and balance abilities of the TEC participants showed more improvement after the treadmill walking sessions than those of the TEO participants. Therefore' treadmill walking with visual deprivation may be useful for the rehabilitation of patients with chronic stroke.

Effect of blocked vision treadmill training on knee joint proprioception of patients with chronic stroke.

[Purpose] The purpose of this study was to compare the effect of treadmill training with the eyes closed and eyes open on the joint position sense of chronic stroke patients. [Subjects and Methods] Thirty patients with chronic stroke participated in this study. Patients performed the timed up and go test and were assigned to one of two treadmill training groups with and without visual deprivation. The treadmill gait training for each group lasted 40 minutes, and sessions were held 3 times a week for 4 weeks. The knee joint proprioception was measured using the Biodex System Pro 3 before and after the intervention. [Results] The knee joint proprioception of the treadmill training with blocked vision group showed more significant improvement after the treadmill training sessions than that of the eyes open group. [Conclusion] This study demonstrated that treadmill training with blocked vision may be useful for the proprioceptive sensory rehabilitation of patients with chronic stroke.

Comparison between Intramedullary Nailing and Percutaneous K-Wire Fixation for Fractures in the Distal Third of the Metacarpal Bone.

BACKGROUND: To compare clinical and radiographic outcomes between intramedullary nail fixation and percutaneous K-wire fixation for fractures in the distal third portion of the metacarpal bone. METHODS: A single-institutional retrospective review identified 41 consecutive cases of metacarpal fractures between September 2009 and August 2013. Each of the cases met the inclusion criteria for closed, extra-articular fractures of the distal third of the metacarpal bone. The patients were divided by the method of fixation (intramedullary nailing or K-wire). Outcomes were compared for mean and median total active motion of the digit, radiographic parameters, and period until return to work. Complications and symptoms were determined by a questionnaire. RESULTS: During the period under review, 41 patients met the inclusion criteria, and the fractures were managed with either intramedullary nailing (n=19) or percutaneous K-wire fixation (n=22). The mean and median total active range of motion and radiographic healing showed no statistically significant difference between the two groups. No union failures were observed in either group. The mean operation time was shorter by an average of 14 minutes for the percutaneous K-wire fixation group. However, the intramedullary nailing group returned to work earlier by an average of 2.3 weeks. Complications were reported only in the K-wire fixation group. CONCLUSIONS: Intramedullary nailing fixation is advisable for fractures in the distal third of the metacarpal bone. It provides early recovery of the range of motion, an earlier return to work, and lower complication rates, despite potentially requiring a wire removal procedure at the patient's request.

Percutaneous short-segment pedicle screw placement without fusion in the treatment of thoracolumbar burst fractures: is it effective?: comparative study with open short-segment pedicle screw fixation with posterolateral fusion.

BACKGROUND: Since introduction of the pedicle screw-rod system, short-segment pedicle screw fixation has been widely adopted for thoracolumbar burst fractures (TLBF). Recently, the percutaneous pedicle screw fixation (PPSF) systems have been introduced in spinal surgery; and it has become a popularly used method for the treatment of degenerative spinal disease. However, there are few clinical reports concerning the efficacy of PPSF without fusion in treatment of TLBF. The purpose of this study was to determine the efficacy and safety of short-segment PPSF without fusion in comparison to open short-segment pedicle screw fixation with bony fusion in treatment of TLBF. METHODS: This study included 59 patients, who underwent either percutaneous (n = 32) or open (n = 27) short-segment pedicle screw fixation for stabilization of TLBF between December 2003 and October 2009. Radiographs were obtained before surgery, immediately after surgery, and at the final follow-up for assessment of the restoration of the spinal column. For radiologic parameters, Cobb angle, vertebral wedge angle, and vertebral body compression ratio were assessed on a lateral thoracolumbar radiograph. For patient's pain and functional assessment, the visual analogue scale (VAS), the Frankel grading system, and Low Back Outcome Score (LBOS) were measured. Operation time, and the amount of intraoperative bleeding loss were also evaluated. FINDINGS: In both groups, regional kyphosis (Cobb angle) showed significant improvement immediately after surgery, which was maintained until the last follow up, compared with preoperative regional kyphosis. Postoperative correction loss showed no significant difference between the two groups at the final follow-up. In the percutaneous surgery group, there were significant declines of intraoperative blood loss, and operation time compared with the open surgery group. Clinical results showed that the percutaneous surgery group had a lower VAS score and a better LBOS at three months and six months after surgery; however, the outcomes were similar in the last follow-up. CONCLUSIONS: Both open and percutaneous short-segment pedicle fixation were safe and effective for treatment of TLBF. Although both groups showed favorable clinical and radiologic outcomes at the final follow-up, PPSF without bone graft provided earlier pain relief and functional improvement, compared with open TPSF with posterolateral bony fusion. Despite several shortcomings in this study, the result suggests that ongoing use of PPSF is recommended for the treatment of TLBF.

The transdural approach for thoracic disc herniations: a technical note.

Surgery for thoracic disc herniations is still challenging, and the disc excision via a posterior laminectomy is considered risky. A variety of dorsolateral and ventral approaches have been developed. However, the lateral extracavitary and transthoracic approach require extensive surgical exposure. Therefore, we adopted a posterior transdural approach for direct visualization without entry into the thoracic cavity. Three cases that illustrate this procedure are reported here with the preoperative findings, radiological findings and surgical techniques used. After the laminectomy, at the involved level, the dorsal dura was opened with a longitudinal paramedian incision. The cerebrospinal fluid was drained to gain more operating space. After sectioning of the dentate ligaments, gentle retraction was applied to the spinal cord. Between the rootlets above and below, the ventral dural bulging was clearly observed. A small paramedian dural incision was made over the disc space and the protruded disc fragment was removed. Neurological symptoms were improved, and no surgery-related complication was encountered. The posterior transdural approach may offer an alternative surgical option for selected patients with thoracic paracentral soft discs, while limiting the morbidity associated with the exposure.

Intradural spinal metastasis to the cauda equina in renal cell carcinoma: a case report and review of the literature.

STUDY DESIGN: Case description. OBJECTIVES: To describe a case of intradural metastasis from a renal cell carcinoma (RCC) spread to the cauda equina, and review the pertinent medical literature. SUMMARY OF BACKGROUND DATA: Intradural spinal metastasis is rare, accounting for 6% of all spinal metastases. Only 7 cases of intradural metastasis from a RCC to the cauda equina have been previously reported. METHODS: A 41-year-old male presented with a 1-month history of severe back pain radiating to both legs. The patient underwent a right nephrectomy for treatment of a RCC 1-year before admission. Magnetic resonance imaging showed a well-demarcated, intradural extramedullary mass at the L2 vertebra. RESULTS: After a total laminectomy, total excision of the tumor was achieved followed by rapid improvement of the back pain. The tumor was histologically verified as metastatic RCC, identical to that of a previous tumor specimen. The patient was asymptomatic on the 1-year follow-up. CONCLUSION: Although the majority of cauda equina tumors are primary tumors, intradural metastasis should be considered before surgery in patients with previously treated RCC.

The efficacy of the synthetic interbody cage and Grafton for anterior cervical fusion.

STUDY DESIGN: Prospective study of 31 patients who underwent anterior cervical fusion. OBJECTIVE: To investigate the efficacy of polyetheretherketone (PEEK) cages and demineralized bone matrix (DBM) for anterior cervical discectomy and fusion (ACDF). SUMMARY OF BACKGROUND DATA: Although high fusion rates can be achieved with autogenous bone grafts, donor-site morbidity affects the patient's satisfaction with the surgical outcome. METHODS: Thirty-one consecutive patients treated with ACDF using the PEEK cage with DBM (Grafton, Osteotech, Inc., Shrewsbury, NJ) at 42 levels were prospectively evaluated with a minimum of 12-month follow-up (mean: 16 months). Twenty-one patients underwent a single-level ACDF, 9 patients underwent a 2-level ACDF, and 1 patient had a 3-level ACDF. The affected level was C3-C4 in 7 patients; C4-C5 in 9, C5-C6 in 16, and C6-C7 in 10. The neurologic outcomes were evaluated using the VAS score for neck and arm pain and the Japanese Orthopedic Association scoring system for myelopathy at 3, 6, and 12 months. The cervical lordosis and fusion status were assessed on radiographs including flexion/extension radiographs. RESULTS: At 12 months, the radiographs demonstrated grades I, II, and III new bone formation at 1, 13, and 28 levels, respectively. There was a significant improvement in both the neck and arm pain and a significant improvement in the Japanese Orthopedic Association scores at the last follow-up. There was no case with implant-related complications such as cage failure or migration, and no complications associated with the use of Grafton. CONCLUSION: ACDF using the Solis cage packed with Grafton demonstrated good clinical and radiologic outcomes. The fusion rate was comparable with the published results of the traditional ACDF using tricortical iliac crest grafts. Therefore, the results of this study suggest that the ongoing use of the PEEK cage packed with DBM and autologous bone chips in ACDF is a safe and effective alternative to the gold standard of autologous iliac bone grafts.

Post-traumatic intradiploic leptomeningeal cyst of the posterior fossa in an adult.

Intradiploic cysts in the posterior fossa are rare. We report a post-traumatic intradiploic leptomeningeal cyst in an adult and review the diagnosis and pathogenesis of this lesion. A 28-year-old woman presented with a headache and a hard mass in the occipital region. She had a history of head injury as she had fallen from a height at the age of 18 months. CT scans and MRI revealed an expanding intradiploic cyst with the density of cerebrospinal fluid (CSF) and thinning of the inner and outer tables. A bony defect of the inner table connecting to the cisterna magna was also visualized. At surgery, we detected free communication of the CSF between the cystic cavity and the subarachnoid space of the posterior fossa via a defect in the dura and inner table. The dural defect was sutured primarily and covered with the autogenous outer table. An intradiploic cyst of the occipital bone can be detected in adults and might be caused by remote head injuries during childhood. Prompt surgical repair of the dural and bony defect in an adult patient has an excellent prognosis.

Clinical analysis of risk factors related to recurrent chronic subdural hematoma.

OBJECTIVE: Burr hole drainage has been widely used to treat chronic subdural hematoma (CSDH). However, the incidence of recurrent CSDH varies from 3.7 to 30% after surgery. The authors attempted to elucidate the risk factors associated with the recurrence of CSDH in one burr hole drainage technique. METHODS: A total of 255 consecutive cases who underwent one burr hole drainage for CSDH were included in this study. Twenty-four patients (9.4%) underwent a repeated operation because of the recurrence of CSDH. We analyzed retrospectively the demographic, clinical and radiologic factors associated with the recurrence of CSDH. RESULTS: In this study, two risk factors were found to be independently associated with the recurrence of CSDH. The incidence of CSDH recurrence in the high- and mixed-density groups was significantly higher than those in the low- and iso-density groups (p<0.001). Bleeding tendency such as in leukemia, liver disease and chronic renal failure was also significantly associated with recurrence of CSDH (p=0.037). CONCLUSION: These results suggest that high- and mixed- density shown on computed tomographic scan was closely relates with a high incidence of recurrence. Therefore, the operation could be delayed in those cases unless severe symptoms or signs are present. Reoperation using the previous burr hole site is a preferred modality to treat the recurrent CSDH.

An intraosseous malignant peripheral nerve sheath tumor of the cervical spine: a case report and review of the literature.

STUDY DESIGN: Case description. OBJECTIVES: To report a rare case of intraosseous malignant peripheral nerve sheath tumors (MPNST), and review the pertinent medical literature. SUMMARY OF BACKGROUND DATA: The spinal MPNST that develops from spinal nerve roots and secondary bony erosion is well-known entity. However, primary intraosseous MPNSTs of the spine are extremely rare. METHODS: A 41-year-old male presented with a 1-month history of radiating pain to his right shoulder and arm. Magnetic resonance images showed a large extradural mass extending from C6 to T1 with destruction of the posterior elements of C6, C7, and T1. Complete excision of the tumor and posterior stabilization were performed through a posterior approach. The tumor was noted to originate from the posterior element of C7. RESULTS: The histopathology was diagnostic for a MPNST. Adjuvant chemotherapy was administered after surgery. The patient remained symptom-free for 30 months after surgery without local recurrence or metastasis. CONCLUSION: We report an intraosseous MPNST of the cervical spine. Complete surgical excision and adjuvant chemotherapy resulted in a good functional outcome. MPNST should be added to the differential diagnosis of primary bone tumors causing spinal cord compression.