Shih-Tseng Lee

Chang Gung University, Hsin-chu-hsien, Taiwan, Taiwan

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Publications (116)200.25 Total impact

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    ABSTRACT: To determine the effects of antiepileptic drug compounds on glioblastoma cellular growth, we exposed glioblastoma cell lines to select antiepileptic drugs. The effects of selected antiepileptic drugs on glioblastoma cells were measured by MTT assay. For compounds showing significant inhibition, cell cycle analysis was performed. Statistical analysis was performed using SPSS. The antiepileptic compounds selected for screening included carbamazepine, ethosuximide, gabapentin, lamotrigine, levetiracetam, magnesium sulfate, oxcarbazepine, phenytoin, primidone, tiagabine, topiramate, valproic acid, and vigabatrin. Dexamethasone and temozolomide were used as a negative and positive control respectively. Our results showed temozolomide and oxcarbazepine significantly inhibited glioblastoma cell growth and reached IC50 at therapeutic concentrations. The other antiepileptic drugs screened were unable to reach IC50 at therapeutic concentrations. The metabolites of oxcarbazepine were also unable to reach IC50. Dexamethasone, ethosuximide, levetiracetam, and vigabatrin showed some growth enhancement though they did not reach statistical significance. The growth enhancement effects of ethosuximide, levetiracetam, and vigabatrin found in the study may indicate that these compounds should not be used for prophylaxis or short term treatment of epilepsy in glioblastoma. While valproic acid and oxcarbazepine were effective, the required dose of valproic acid was far above that used for the treatment of epilepsy and the metabolites of oxcarbazepine failed to reach significant growth inhibition ruling out the use of oral oxcarbazepine or valproic acid as monotherapy in glioblastoma. The possibility of using these compounds as local treatment is a future area of study.
    No preview · Article · Jan 2016 · Journal of Neuro-Oncology
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    ABSTRACT: Non-functioning pituitary macroadenomas (NFPAs) are the most prevalent pituitary macroadenomas. One common symptom of NFPA is hypogonadism, which may require long-term hormone replacement. This study was designed to clarify the association between the pre-operative tumor volume, pre-operative testosterone level, intraoperative resection status and the need of long-term post-operative testosterone replacement. Between 2004 and 2012, 45 male patients with NFPAs were enrolled in this prospective study. All patients underwent transsphenoidal surgery. Hypogonadism was defined as total serum testosterone levels of <2.4 ng/mL. The tumor volume was calculated based on the pre- and post-operative magnetic resonance images. We prescribed testosterone to patients with defined hypogonadism or clinical symptoms of hypogonadism. Hormone replacement for longer than 1 year was considered as long-term therapy. The need for long-term post-operative testosterone replacement was significantly associated with larger pre-operative tumor volume (p = 0.0067), and lower pre-operative testosterone level (p = 0.0101). There was no significant difference between the gross total tumor resection and subtotal resection groups (p = 0.1059). The pre-operative tumor volume and testosterone level impact post-operative hypogonadism. By measuring the tumor volume and the testosterone level and by performing adequate tumor resection, surgeons will be able to predict post-operative hypogonadism and the need for long-term hormone replacement.
    No preview · Article · Nov 2015 · Scientific Reports
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    ABSTRACT: The objective of the present study was to determine whether selective inflammatory cytokine concentrations within cerebrospinal fluid are useful markers for the differential diagnosis of aseptic and bacterial meningitis within neurosurgical patients. Prospective, open-label, observational, cohort study. Neurosurgical ICU, Chang Gung Memorial Hospital. Thirty-two consecutive neurosurgical patients who had postoperative fever following external ventricular drain insertion for the treatment of brain injury underwent serial cerebrospinal fluid cytokine analysis pre and post fever to determine the value of such markers in ascertaining the differential diagnosis of meningitis. Cerebrospinal fluid samples were collected on the day of fever onset, as well as on day 2 and 4 pre and post fever development. Tumor necrosis factor-α, interleukin-1β, interleukin-6, interleukin-8, transforming growth factor-β, and procalcitonin were subsequently analyzed using enzyme-linked immunosorbent assay analysis techniques. Inflammatory marker levels were compared among febrile aseptic, bacterial, and nonmeningitis patients to determine cerebrospinal fluid inflammatory changes over time. Significant increases in cerebrospinal fluid tumor necrosis factor -α, interleukin-1β, interleukin-6, and interleukin-8 levels were observed within patients with bacterial meningitis at fever onset, which was not evident in aseptic or nonmeningitis patients. Furthermore, significant increases in cerebrospinal fluid tumor necrosis factor-α, interleukin-1β, interleukin-6, and interleukin-8 levels were detected as early as 4 days prior to fever onset within patients with bacterial meningitis when compared with both aseptic and nonmeningitis groups. Interestingly, procalcitonin was only significantly increased in patients with bacterial meningitis on the fourth day post fever. The present study suggests that raised cerebrospinal fluid tumor necrosis factor -α, interleukin-1β, and interleukin-8 in a temporal manner may indicate early bacterial meningitis development in neurosurgical patients, enabling earlier diagnostic certainty and improved patient outcomes.
    Full-text · Article · Jul 2015 · Critical care medicine
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    ABSTRACT: Corpus callosum involvement is associated with poorer survival in high grade glioma (HGG), but the prognostic value in low grade glioma (LGG) is unclear. To determine the prognostic impact of corpus callosum involvement on progression free survival (PFS) and overall survival (OS) in HGG and LGG, the records of 233 glioma patients treated from 2008 to 2011 were retrospectively reviewed. Preoperative magnetic resonance (MR) images were used to identify corpus callosum involvement. Age, sex, preoperative Karnofsky performance scale, postoperative Eastern Cooperative Oncology Group (ECOG) score and extent of resection (EOR) were evaluated with respect to PFS and OS. The incidence of corpus callosum involvement was similar among HGG (14 %) and LGG (14.5 %). Univariate analysis revealed that PFS and OS were significantly shorter in both WHO grade II and grade IV glioma with corpus callosum involvement (both, p p = 0.03), while EOR, instead of corpus callosum involvement (p = 0.16), was an independent factor associated with PFS in grade IV glioma (p p = 0.16, 0.17 and 0.56 in grade II, III and IV gliomas, respectively). Corpus callosum involvement happened in both LGG and HGG, and is associated with lower EOR and higher postoperative ECOG score both in LGG and HGG. Corpus callosum involvement tends to be an independent prognostic factor for PFS in LGG, but not for OS in LGG or in HGG.
    No preview · Article · Jun 2015 · Journal of Neuro-Oncology
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    ABSTRACT: Extracranial-to-intracranial (EC-IC) arterial bypass is a technically demanding procedure used to treat complex cerebral artery diseases. The indications, proper surgical techniques, and outcomes of this procedure have been under debate over the recent decades. Between January 2004 and December 2012, 28 patients, including patients with cerebral artery occlusion, intracranial aneurysm, cranial base tumor, and Moyamoya disease, underwent EC-IC bypass. Patients' records were retrospectively reviewed for demography, indications, complications, high-flow versus low-flow bypass, patency rate of bypass, and neurological outcome. The patients were sorted into prophylactic (n = 16) and therapeutic (n = 12) groups based on the preoperative presentation of their neurological symptoms. Follow-up evaluation was performed at a mean of 32.7 ± 24.3 months. The overall patency rate of bypass was 100%, the postoperative stroke rate was zero, and the surgical complication rate was 14.3%. There was no significant difference in the bypass patency rate between the 2 groups or between the high-flow and low-flow bypass patients. Patients who underwent prophylactic bypass had minimal surgical and total complications (P = 0.03 and P < 0.01, respectively) and a better neurological outcome. Surgical complications were more common in patients who underwent therapeutic bypass (25%). The collaboration of neurosurgeons and plastic surgeons in performing EC-IC bypass can result in excellent outcomes with a high bypass patency rate and few complications, particularly for prophylactic EC-IC bypass.
    Preview · Article · Apr 2015
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    ABSTRACT: Background: A medical record is an important source of information regarding medical care and medical record review plays an important role in the evaluation of the teaching proficiency. The study analyzed the difference between internal and external auditing when conducting medical record review for faculty promotion in a study institute. Methods: We analyzed the scores related to the medical records maintained by applicants for the faculty promotion of attending physicians during the period between 2008 and 2010 at the Chang Gung Memorial Hospital. The scores were obtained from one internal reviewer of the study institute and two external reviewers from other medical centers, and routine scores were obtained from the Committee of Medical Record 1 year before application. Pearson's correlation coefficient was used to analyze the correlation and statistical significance. Results: There were 259 applicants for faculty promotion enrolled in this study [professors (n = 33, 13%), associate professors (n = 63, 24%), assistant professors (n = 90, 35%), lecturers (n = 73, 28%)]. The scores of the external reviewers 1 and 2 were correlated with routine scores (r = 0.187, p = 0.002; r = 0.198, p = 0.001; N= 259), respectively. The correlation between external reviewers' average and ordinary scores was significant for assistant professor (r = 0.334, p = 0.001, n = 90) and professor grades (r = 0.469, p = 0.006, n = 33). However, the internal reviewer scores did not correlate with the routine scores (r = 0.073, p = 0.241, N = 259). Conclusions: The scores from external reviewers correlated more with routine scores than the scores from internal reviewers, suggesting that utilizing an external auditing system of medical records for the faculty promotion of attending physicians is quite feasible and balanced.
    Preview · Article · Feb 2015
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    ABSTRACT: Medical surgery is considered as a difficult technique and needs to be performed by well-trained and experienced medical personnel to complete the procedure. During a complicated surgery, an experienced surgeon at distant can provide sophisticated instruction or guidance to help the operating surgeon when it is necessary. In this study, we have designed an interactive augmented reality system for remote surgical assistance. The surgeon at the remote site can indicate or contour a region of interest (ROI) by manually drawing on streaming images which were captured by the camera at the local site. The coordinate of the ROI in the 3-D physical space can be estimated by using the CT images of the patient. Therefore, the ROI and the anatomical information of the CT images can be rendered on the captured images, overlaid on the patient and projected onto a head-mounted display of the local operating surgeon, providing an across-space augmented reality visualization.
    No preview · Article · Feb 2015 · Applied Mathematics & Information Sciences
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    ABSTRACT: Objective: Rehabilitation has been reported to improve pain and disability for patients after lumbar surgery. However, studies to investigate the rehabilitation intervention for lumbar decompression surgery during hospitalization are scarce. The aim of this study was to examine outcomes of perioperative rehabilitation intervention for patients who underwent lumbar decompression surgery (LDS). Methods: Patients aged 18-65 years old who received their first LDS were randomized into the perioperative rehabilitation group (PG) or control group (CG). The PG received rehabilitation intervention during hospitalization for lumbar decompression surgery. Pain, functional capacity, Roland-Morris Disability Questionnaire (RMDQ), and Short-Form Health Survey (SF-12) were assessed on admission, at discharge, and at follow-ups one month, three months, and six months after surgery. Two-way repeated measures ANOVAs were used for statistical analysis. Results: A total of 60 patients scheduled for decompression surgery for lumbar stenosis were enrolled into the study. After surgery, the PG showed significant pain relief and improvement of disability as well as quality of life, but there were no significant functional improvements compared with the CG. Conclusions: The findings of this study indicate that the rehabilitation intervention during hospitalization improves pain intensity as well as disability and quality of life, yet has limited effects on the functional performance over time up to six months post-surgery in patients who received LDS. The study suggest that rehabilitation interventions during hospitalization must include regular support for patient adherence to the intervention program and focus on task-oriented programs for lower extremities such as closed-chain exercises in functional postures.
    Full-text · Article · Feb 2015 · Clinical Neurology and Neurosurgery
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    ABSTRACT: The aim of this study was to examine the clinical outcomes of treating atypical meningioma at the skull base region following surgical resection and adjuvant radiotherapy, and to analyze the association between clinical characteristics and progression free survival. Twenty-eight patients with skull base atypical meningiomas underwent microsurgical resection between June 2001 and November 2009. The clinical characteristics of the patients and meningiomas, the extent of surgical resection, and complications after treatment were retrospectively analyzed. Thirteen patients (46.4%) had disease recurrence or progression during follow up time. The median time to disease progression was 64 months. The extent of the surgical resection significantly impacted prognosis. Gross total resection (GTR) of the tumor improved progression free survival (PFS) compared to subtotal resection (STR, p=0.011). An older patient age at diagnosis also resulted in a worse outcome (p=0.024). An MIB-1 index <8% also contributed to improved PFS (p=0.031). None of the patients that underwent GTR and received adjuvant radiotherapy had tumors recur during follow up. STR with adjuvant radiotherapy tended to result in better local tumor control than STR alone (p=0.074). Three of 28 patients (10.7%) developed complications after microsurgery. The GTR group had a higher rate of complications than those with STR. There were no late adverse effects after adjuvant radiotherapy during follow up. For patients with skull base atypical meningiomas, GTR is desirable for longer PFS, unless radical excision is expected to lead to severe complications. Adjuvant radiation therapy is advisable to reduce tumor recurrence regardless of the extent of surgical resection. Age of disease onset and the MIB-1 index of the tumor were both independent prognostic factors of clinical outcome. Copyright © 2014 Elsevier B.V. All rights reserved.
    No preview · Article · Nov 2014 · Clinical Neurology and Neurosurgery
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    ABSTRACT: This is a retrospective cases series.Objective Tropical pyomyositis of Erector Spinae muscle (ESPM) is a rare muscular infection which may extend into the intraspinal canal to become spinal epidural abscess (ESPM-SEA). If left untreated, it may cause catatrophic spinal cord dysfunction and lead to irreversible paralysis. A series of eight such cases is present, in order to provide proper surgical options and clarify the prognostic factors of the disease.Summary of Background DataMerely six sporadic case reports had been found in the literature. Surgical debridement and laminectomy to drain the intraspinal abscess combined with systemic antibiotics were the choice of treatment to treat the disease with good therapeutic effect.Methods Inpatient charts of the patients were reviewed. The therapeutic effect and functional neurological recovery are correlated with the demographic characteristics of the patients, neurological deficits before drainage, and the different procedures of drainage.ResultsOld age, long ESPM-SEA (>6.5 vertebral segments), spinal cord dysfunction as well as complete paralysis before the interventional procedures is significantly correlated with poor functional neurological recovery (Sperman's coeffiecient correlation, all p < 0.05). Pig-tail drainage of ESPM combined with adequate systemic antibiotics could cure if infection presents with lumbar radiculopathy only, but it failed to rescue the spinal cord dysfuction in two patients presents with complete paralysis. Surgical drainage of ESPM with mini-laminotomy to drain ESPM-SEA combined with systemic antibiotics provided good functional recovery of patients, despite of prolonged pre-operative complete paralysis.Conclusion Early drainage of the ESPM and related epidural abscess combined with systemic antibiotics can provide excellent therapeutic effect of ESPM-SEA. Open drainage with mini-laminotomy is superior to pig-tail drainage when spinal cord dysfunction occurred associated with ESPM-SEA.
    No preview · Article · Nov 2014 · Clinical Neurology and Neurosurgery
  • Hung-Yi Lai · Ching-Yi Lee · Angela Chiu · Shih-Tseng Lee
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    ABSTRACT: Objective This study uses a validated learning style inventory to delineate the learning style that best defines a successful practitioner in the field of neurosurgery. Methods The Kolb Learning Style Inventory (LSI), a validated assessment tool, was administered to all practicing neurosurgeons, neurosurgical residents, and neurology residents employed at Chang Gung Memorial Hospital, an institution that provides both primary and tertiary clinical care, in three locations, Linkou, Kaohsiung, and Chiayi. Eighty-one participants entered the study and all completed the study. Results Neurosurgeons preferred the assimilating learning style (52%), followed by the diverging learning style (39%). Neurosurgery residents were slightly more evenly distributed across the learning styles, however, they still favored assimilating (32%) and diverging (41%). Neurology residents had the most clearly defined preferred learning style with assimilating (76%) obtaining the large majority, and diverging (12%) being a distant second. Conclusions The assimilating and diverging learning styles are the preferred learning styles among neurosurgeons, neurosurgery residents, and neurology residents with the assimilating learning style typically being the primary learning style for neurosurgeons and neurology residents. Neurosurgical residents start off with a diverging learning style and progress towards an assimilating learning style as they works towards becoming practicing neurosurgeons. The field of neurosurgery has limited opportunities for active experimentation which may explain why individuals that prefer reflective observation are more likely to succeed in this field.
    No preview · Article · Sep 2014 · World Neurosurgery
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    ABSTRACT: Background: Cervios ChronOS (CCOS) is a cervical cage containing artificial bone. To date, very few reports have documented the results of its clinical outcome. This study describes the outcomes of CCOS for anterior cervical discectomy with interbody fusion (ACD-IBF) in patients at the Chang Gung Memorial Hospital. Materials and Methods: Retrospectively reviewed 32 patients underwent ACD-IBF with 51 CCOS cages from 2007 to 2008. All patients had either intractable preoperative cervical radiculopathy or myelopathy for 3 months duration and underwent follow-up for >2 years. Postoperative outcomes were classified as favorable or unfavorable. Rigid bone fusion was defined as an interspinous distance ≤2 mm on dynamic lateral cervical radiographs and absence of radiolucent gaps between vertebral endplates and CCOS. Anterior disk height and interbody height were used for subsidence evaluation. Results: The postoperative outcomes were favorable in 86.7% and unfavorable in 13.3% of the patients. Two years after surgery, 90.01% had rigid bone fusion. The anterior disk height was increased at postoperative day 1 and month 3 (P<0.05), but gradually decreased to the preoperative height at sixth month (P>0.05). The interbody height did not change significantly throughout the follow-up. The segmental angle had significant lordosis at postoperative day 1 and month 3 (P<0.05), but kyphotic changes gradually restored the preoperative angle. The clinical outcome was significantly related to the rigid bone fusion rate (P=0.0186). Furthermore, smoking was a contributing factor to poor clinical outcome (P=0.035), and diabetes mellitus was a contributing factor to poor interbody fusion (P=0.009) Conclusions: The CCOS cage can be safely and effectively used as a disk substitute after ACD-IBF. In diabetes mellitus patients, adjuvant-fixation instruments might improve postoperative bone fusion.
    No preview · Article · Aug 2014 · Neurosurgery Quarterly
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    ABSTRACT: This paper presents the use of fuzzy models to explicitly consider sensor uncertainty and finite resolution in solving the SLAM (simultaneous localization and mapping) problem for autonomous mobile robots. The approach establishes fuzzy confidence models in describing occupied obstacles and available space. The problem is transformed into an optimization task of minimizing the alignment error between newly scanned local fuzzy maps and selected parts of a developing global fuzzy map. In aligning local fuzzy maps into a global fuzzy map, we developed a prediction strategy to crop the most potential part from the sensed local fuzzy maps to be overlapped with the global fuzzy map. A mobile vehicle equipped with a laser range finder, the Hokuyo URG-04LX, is used to demonstrate the procedure of fuzzy map building. Experimental results show that the proposed architecture is effective in generating a comprehensive global fuzzy map, which is suitable for both human comprehension and path design during real-time navigation.
    Preview · Article · Jun 2014 · Mathematical Problems in Engineering
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    ABSTRACT: Background: Arteriovenous malformation (AVM) is one of the cerebrovascular diseases that bear a high risk of hemorrhage. The treatment modalities include microsurgical resection, endovascular embolization, stereotactic radiosurgery, or combinations that vary widely. Several large series have been reported, while data from Asian populations were few. The aim of this study was to examine the efficacy of linear accelerator stereotactic radiosurgery (LINAC SRS) for the treatment of intracranial AVMs, to evaluate the hemorrhage rate and to analyze associated factors. Methods: One hundred and sixteen patients with AVM were treated with LINAC SRS in a single institute between September 1994 and May 2005 and were retrospectively evaluated. The demographics of patients, clinical characteristics of AVM, the treatment modalities, and the parameters of the LINAC SRS were analyzed. Delayed toxicity and hemorrhage rate after treatment were also evaluated. The AVM obliteration and bleed rates were calculated using the Kaplan-Meier method and Cox regression analyses. Results: The efficacy rate with total obliteration after treatment was 81.9% (95 of 116 patients). The median interval to achieve total obliteration was 49 months. Microsurgical resection combined with SRS for residual AVMs achieved better obliteration rates compared to SRS alone (statistically significant, p = 0.001), while no significant difference was found between the embolization group and the group with no prior treatment (p = 0.895). The Spetzler-Martin grade of AVM is a relative factor of obliteration, higher grades resulting in a worse outcome (p = 0.009). Obliteration was significantly influenced by AVM volume in univariate analysis (p = 0.034), and volume <5 cm(3) contributed to improved obliteration (p = 0.01). There was no statistically significant difference in the hemorrhagic rate and the complication rate between ruptured and unruptured AVMs, while the unruptured group had a higher obliteration rate (p = 0.024). The annual hemorrhage rate after LINAC SRS treatment was 1.9%. The bleeding rate was 3.3% in the first year after radiosurgery, 2.1% in the second year, 1.9% between the second and fifth year, and 1.5% between the fifth and tenth year. Patients with hemorrhagic events before radiosurgery appeared to have a higher rebleeding risk during the latency period. Twenty-three patients (19.8%) had late adverse effects with regard to posttreatment radiological follow-up, but only 1 (0.8%) had newly developed neurological deficits. Conclusion: LINAC SRS achieved a high obliteration rate and reduced the risk of hemorrhage effectively in ruptured and unruptured intracranial AVMs. Prior microsurgical resection provided better outcome, while embolization showed no benefit. Adverse effects after treatment are acceptable and require long-term follow-up.
    No preview · Article · Jun 2014 · Cerebrovascular Diseases
  • Po-Chuan Hsieh · Shih-Tseng Lee · Jyi-Feng Chen
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    ABSTRACT: Degenerative spondylolisthesis of the spine is less common in the lower thoracic region than in the lumbar and cervical regions. However, lower thoracic degenerative spondylolisthesis may develop secondary to intervertebral disc degeneration. Most of our patients are found to have concomitant lumbar spondylosis. By retrospective review of our cases, current diagnosis and treatments for this rare disease were discussed. We present a series of 5 patients who experienced low back pain, progressive numbness, weakness and even paraparesis. Initially, all of them were diagnosed with lumbar spondylosis at other clinics, and 1 patient had even received prior decompressive lumbar surgery. However, their symptoms continued to progress, even after conservative treatments or lumbar surgeries. These patients also showed wide-based gait, increased deep tendon reflex (DTR), and urinary difficulty. All these clinical presentations could not be explained solely by lumbar spondylosis. Thoracolumbar spinal magnetic resonance imaging (MRI), neurophysiologic studies such as motor evoked potential (MEP) or somatosensory evoked potential (SSEP), and dynamic thoracolumbar lateral radiography were performed, and a final diagnosis of lower thoracic degenerative spondylolisthesis was made. Bilateral facet effusions, shown by hyperintense signals in T2 MRI sequence, were observed in all patients. Neurophysiologic studies revealed conduction defect of either MEP or SSEP. One patient refused surgical management because of personal reasons. However, with the use of thoracolumbar orthosis, his symptoms/signs stabilized, although partial lower leg myelopathy was present. The other patients received surgical decompression in association with fixation/fusion procedures performed for managing the thoracolumbar lesions. Three patients became symptom-free, whereas in 1 patient, paralysis set in before the operation; this patient was able to walk with assistance 6 months after surgical decompression. The average Nurick scale score improved from 3.75 before the operation to 2 after the operation. Lower thoracic degenerative spondylolisthesis is a rare disease, which may occur concomitantly with lumbar spondylosis and confuse clinicians. Diagnosis should be made properly, especially because symptoms/signs cannot be explained purely on the basis of the available images. Micromotion due to facet joint laxity and disc degeneration was believed as the cause of progressive myelopathy. Posterior decompression with fixation/fusion procedure was appropriate for the treatment of thoracic spondylolisthesis secondary to thoracic disc degeneration.
    No preview · Article · Mar 2014 · Clinical neurology and neurosurgery
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    ABSTRACT: This work investigates the calibration of a stereo vision system based on two PTZ (Pan-Tilt-Zoom) cameras. As the accuracy of the system depends not only on intrinsic parameters, but also on the geometric relationships between rotation axes of the cameras, the major concern is the development of an effective and systematic way to obtain these relationships. We derived a complete geometric model of the dual-PTZ-camera system and proposed a calibration procedure for the intrinsic and external parameters of the model. The calibration method is based on Zhang's approach using an augmented checkerboard composed of eight small checkerboards, and is formulated as an optimization problem to be solved by an improved particle swarm optimization (PSO) method. Two Sony EVI-D70 PTZ cameras were used for the experiments. The root-mean-square errors (RMSE) of corner distances in the horizontal and vertical direction are 0.192 mm and 0.115 mm, respectively. The RMSE of overlapped points between the small checkerboards is 1.3958 mm.
    No preview · Article · Jan 2014 · Proceedings of SPIE - The International Society for Optical Engineering
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    ABSTRACT: Developing matching algorithms from stereo image pairs to obtain correct disparity maps for 3D reconstruction has been the focus of intensive research. A constant computational complexity algorithm to calculate dissimilarity aggregation in assessing disparity based on separable successive weighted summation (SWS) among horizontal and vertical directions was proposed but still not satisfactory. This paper presents a novel method which enables decoupled dissimilarity measure in the aggregation, further improving the accuracy and robustness of stereo correspondence. The aggregated cost is also used to refine disparities based on a local curve-fitting procedure. According to our experimental results on Middlebury benchmark evaluation, the proposed approach has comparable performance when compared with the selected state-of-the-art algorithms and has the lowest mismatch rate. Besides, the refinement procedure is shown to be capable of preserving object boundaries and depth discontinuities while smoothing out disparity maps.
    Preview · Article · Jan 2014 · Mathematical Problems in Engineering
  • Article: Response.
    Ching-yi Lee · Shih-Tseng Lee

    No preview · Article · Dec 2013 · Journal of neurosurgery. Spine
  • Ching-yi Lee · Shih-Tseng Lee

    No preview · Article · Dec 2013 · Journal of Neurosurgery Spine
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    ABSTRACT: Anterior cervical disectomy and fusion (ACDF) is a highly effective and safe method for spinal cord and cervical root decompression. However, vocal cord paralysis (VCP) remains an important cause of postoperative morbidity. The true incidence and recovery course of postoperative VCP is still uncertain. This study is a report on VCP after ACDF to evaluate the incidence, recovery course, and possible risk factors. From 2004 to 2008, 1,895 consecutive patients underwent ACDF in our hospital and were followed up for at least 3 years. All surgeons were well trained and used a right-sided exposure. Prolonged VCP, where patients suffered from postoperative VCP lasting more than 3 months, was recorded and analyzed. In this retrospective study, 9 of the 1,895 patients (0.47 %) documented prolonged VCP lasting over 3 months. Six of the nine patients had total recovery within 9 months. Only three patients (0.16 %) still had symptoms even after 3 years postoperatively. All symptoms of VCP, except hoarseness, could be improved. After matching with 36 non-VCP patients, no differences with regard to longer operative or anesthesia time, shorter neck, obesity, and prevertebral edema. All cases of prolonged course of postoperative VCP occurred in patients who underwent exposure at the C67 level. In our study, only 0.47 % documented prolonged postoperative VCP, while most patients recovered within 9 months. However, if symptoms last longer, there could be almost permanent VCP (0.16 %). In our study, choking and dysphagia subsided mostly within 6 months, but hoarseness remained. The exposure of the C67 level obviously was a risk factor for postoperative VCP.
    No preview · Article · Nov 2013 · European Spine Journal

Publication Stats

1k Citations
200.25 Total Impact Points


  • 2000-2015
    • Chang Gung University
      • • School of Medicine
      • • College of Medicine
      • • Department of Neurology
      Hsin-chu-hsien, Taiwan, Taiwan
  • 1986-2015
    • Chang Gung Memorial Hospital
      • Division of Neurosurgery
      T’ai-pei, Taipei, Taiwan
  • 2010
    • Xiamen Chang Gung Hospital
      Amoy, Fujian, China