Yan-Fen Hwang

A comparative study of the patients with bilateral or unilateral chronic subdural hematoma: precipitating factors and postoperative outcomes.

BACKGROUND : Chronic subdural hematoma (CSDH) is a relatively frequent problem in neurologic or neurosurgical practice. Although CSDH is a well-known disease, data on bilateral CSDH are scarce compared with data on unilateral CSDH. The purpose of this study was to compare the clinical presentations, precipitating factors, computed tomography (CT) scan findings, postoperative complications, and outcomes between patients with bilateral and unilateral CSDH. METHODS : A retrospective study was performed on 129 surgical patients with CSDH from January 2002 to January 2005. These patients were divided into two groups: bilateral CSDH (45 cases) and unilateral CSDH (84 cases). Clinical presentations, precipitating factors, CT scan findings, postoperative complications, and outcomes of patients were analyzed. RESULTS : The mean age was 75 years for patients with bilateral CSDH and was 68 years for patients with unilateral CSDH (p = 0.696). Males predominated in each group (p = 0.696). The frequency of presenting symptoms of nausea and vomiting, headache, or unsteady gait was significantly greater in bilateral CSDH than in unilateral CSDH (p < 0.05). The incidence of usage of anticoagulant and antiplatelet therapy was significantly higher in bilateral CSDH group than in unilateral CSDH group (p < 0.05). The frequency of marked midline shift on CT scans was significantly greater in unilateral CSDH than in bilateral CSDH (p < 0.05). Coexisting systemic diseases, postoperative complications, and outcomes had no significant differences between both groups. CONCLUSIONS : Bilateral CSDH tended to occur more in patients with anticoagulant or antiplatelet therapy. Compared with patients with unilateral CSDH, patients with bilateral CSDH had more symptoms of increased intracranial pressure and lower incidences of midline shift on CT scans. Most patients with either bilateral or unilateral CSDH had a good postoperative outcome.

Outcome analyses of interbody titanium cage fusion used in the anterior discectomy for cervical degenerative disc disease.

Anterior discectomy and fusion to treat cervical degenerative disc disease is the preferred procedure for many spine surgeons. The ideal device for structural reconstruction of the anterior cervical spine remains controversial. The purpose of this prospective study was to investigate the effectiveness of a non-threaded titanium cage in performing anterior spinal fusion for cervical degenerative disc disease. The clinical and radiologic data of 78 consecutive patients were reviewed. Neurologic outcome was assessed using Odoms criteria. Neck pain was graded using a 10-point visual analog scale. The cervical spinal curvature, the height of foramina, and fusion status were evaluated on preoperative and postoperative radiographs. Mean follow-up was 24.9 (range 18-35) months. An excellent or good result was found in 92% of the patients with radiculopathy, 69% of those with myelopathy, and 73% of those with myeloradiculopathy. Statistical analyses also showed improvement of cervical pain after surgery (P < 0.001) and a significant increase in foraminal height (P = 0.035). Cervical kyphosis was present in 27 (34%) patients before surgery; it was corrected to lordosis in 9. The fusion rate at 12 months and 24 months was 91% and 95%, respectively. No surgery or cage-related complication occurred in these patients. Non-threaded interbody cage fusion in this study achieved a high fusion rate and had a good neurologic outcome. These results suggest that non-threaded cage fusion is a safe and effective method for anterior cervical discectomy.

Primary spinal tumors in children

Nine patients, 16 years of age or younger with primary spinal cord tumors, diagnosed between 1991 and 2003 at The Kaohsiung University Hospital, were reviewed retrospectively. There were 2 female and 7 male patients. Two tumors were located primarily in the cervical cord (1 meningioma, 1 neurofibroma), five were predominantly thoracic (1 lymphoma, 1 meningioma, 1 astrocytoma, 1 fibrosarcoma and 1 osteoblastoma), one lumbar (ependymoma), and one sacral (Ewings sarcoma). The most common clinical presentation was limb weakness (100%) followed by back pain (44.4%). All the patients underwent laminectomy for removal of their tumors. Five children with benign tumors improved postoperatively. At discharge, these 5 children could walk without assistance and have remained stable with long-term of follow-up. Radical surgery should be considered in benign primary spinal cord tumors. As would be expected, patients diagnosed and treated early and in whom a total resection was achieved had a better prognosis.

Effect of Aspirin and Indomethacin on Prostaglandin E2 Synthesis in C6 Glioma Cells

Prostaglandin E2 (PGE2) plays an important role in immunosuppression and tumor growth. PGE2 inhibitors such as aspirin and indomethacin suppress experimental tumor growth. Little is known of the relationship between PGE2 synthesis in brain tumors and the dose of aspirin or indomethacin. The present study was undertaken to evaluate the effect of different doses of aspirin and indomethacin on PGE2 synthesis in C6 glioma cells. C6 glioma cells were incubated with different concentrations (2, 4, and 8 μM) of aspirin and indomethacin for 1, 2, 4, 6, 8, 12, and 24 hours. Intracellular PGE2 concentration was measured by enzyme immunoassay. Each concentration of aspirin and indomethacin effectively inhibited PGE2 synthesis. Concentrations of 2, 4, and 8 μM of aspirin significantly inhibited PGE2 production at 6, 4, and 1 hours, respectively, and the inhibition persisted for more than 24 hours (p < 0.05). Concentrations of 2 and 4 μM of indomethacin were effective at 4 and 2 hours (p < 0.05), respectively. However, inhibition was not observed beyond 12 hours (p > 0.05). Indomethacin 8 μM was effective at 1 hour and the inhibition persisted beyond 24 hours (p < 0.05). Our study demonstrates that aspirin and indomethacin inhibit PGE2 synthesis in C6 glioma cells and that low‐dose aspirin is as effective as high‐dose aspirin. This study may encourage future clinical use of low‐dose aspirin in the prevention or treatment of brain tumors.

Low-grade astrocytoma associated with abscess formation: case report and literature review.

A rare case of low‐grade astrocytoma associated with abscess formation occurred in a 52‐year‐old man presenting with Brocas aphasia. He underwent craniotomy and tumor removal under the impression of brain tumor with necrotic cystic change. Abscess accumulation within the intra‐axial tumor was found intraoperatively. Literature related to brain abscess with brain tumor is reviewed, with an emphasis on abscesses with astrocytoma. We discuss the common brain tumors that are associated with abscess, pathogens that coexist with brain tumor, and the pathogeneses of coexisting brain abscess and tumor. It is very important to know how to differentiate between and diagnose a brain abscess and tumor, or brain abscess with tumor, preoperatively from clinical presentation and through the use of computed tomography, conventional magnetic resonance imaging, diffusion‐weighted imaging or magnetic resonance spectroscopy.

Differentiation among Metastatic Brain Tumors, Radiation Necroses, and Brain Abscesses Using Proton Magnetic Resonance Spectroscopy

Magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy (MRS) were evaluated for differentiating metastatic brain tumors, radiation necroses, and brain abscesses. Twelve histologically verified lesions in 12 patients were studied using preoperative MRI and proton MRS. The signal intensities of four major metabolites, N‐acetyl aspartate (NAA), choline‐containing compounds (Cho), creatine and phosphocreatine (Cr), and lactate (Lac), were observed over the region of interest. Metastatic brain tumors showed a decrease in NAA/Cr and an increase in Cho/Cr ratios. Radiation necroses showed a decrease in NAA/Cr and no change in Cho/Cr ratios. Brain abscesses showed an increase in Lac/Cr ratio. Correlation with histopathologic findings showed that a high Cho signal was suggestive of a metastatic brain tumor. Lac signals were observed in brain abscesses, presumably reflecting the anerobic glycolysis of living cells. Although more cases and studies are necessary, metabolic information provided by proton MRS combined with MRI is useful for differentiating among metastatic brain tumors, radiation necroses, and brain abscesses.

The expression of thyroid hormone receptor isoforms in human astrocytomas.

BACKGROUND Thyroid hormone plays a major role in normal mammalian brain maturation and affects the development of astrocytes. The expression of TR isoforms has been studied in different neoplasias. Increasing evidence has suggested that aberrant expression of TR isoforms could be associated with tumorigenesis. However, little was studied about the expression of TR isoforms in human astrocytomas. METHODS In this study, RT-PCR was used to examine the expression of human TR isoforms in 34 human astrocytoma samples. RESULTS We compared the TR expression between low grade (WHO grade II) and high grade (WHO grade III and IV). The frequency of TRalpha1 or TRalpha2 expression significantly decreased with the grade of malignancy (P=.005 and P=.043, respectively). However, the frequency of TRbeta1 expression significantly increased with the grades of malignancy astrocytomas (P=.017). CONCLUSIONS Our study demonstrated for the first time that TR isoforms are indeed expressed in human astrocytomas. The expression of TR isoforms is correlated to the malignancy grading of astrocytomas. Our result provides insight into the potential use of hormonal therapy for brain tumors that overexpress or underexpress TRs.

Use of Intrathecal Morphine Infusion for Failed Back Surgery Syndrome: First Experience in Taiwan

Failed back surgery syndrome (FBSS) is a well-recognized complication of spinal surgery and remains a challenge for surgeons. Intrathecal morphine therapy has been increasingly utilized in patients with malignant or non-malignant intractable pain who failed to respond to conventional treatment or could not tolerate these side effects of morphine, but has never been used for treatment of failed back surgery syndrome before in Taiwan. Consequently, this is the first study to use implanted intrathecal morphine infusion for treatment of failed back surgery syndrome in Taiwan. The clinical data of this first case were recorded and analyzed retrospectively to evaluate the efficiency and safety of implanted intrathecal morphine pump for the treatment of failed surgery syndrome. This patient demonstrated significant pain relief and functional status improvement without serious side effects. Although intrathecal morphine infusion was helpful in this first patient with failed back surgery syndrome, long-term efficacy, effectiveness, complication must be evaluated

A Technical Note: Computed Tomography (CT)-Guided Percutaneous Coaxial Pulsed Radiofrequency for Post-Herpetic Neuralgia

Pulsed radiofrequency for postherpetic neuralgia was developed as an alternative to conventional therapies. In fact, the procedures of conventional pulsed radiofrequency are not easy to perform. Authors describe the technique of CT-guided coaxial radiofrequency technique as being performed with a larger bore needle and coaxial system. The external sheath cannula is used as a coaxial system under computed (CT)-guided tomography to direct an accurate localization for radiofrequency treatment of thoracic nerve root postherpetic neuralgia.

CT-Guided Percutaneous Chemical Lumbar Sympathectomy: Technical Note and Outcome

Lumbar sympathectomy may be performed surgically, but this has a reported mortality rate of up to 7 percent, Percutaneous chemical lumbar sympathectomy has been advocated to decrease the mortality. Our goal of this study was to evaluate the feasibility of the technique guided by computerized tomography (CT) scan and to determine the therapeutic value of this therapy. From December 2001 to December 2003, 16 patients underwent 19 percutaneous chemical lumbar sympathectomies using CT guidance for the various accepted indications. There were 5 male patients and 11 female patients, with a mean age of 53.9 years (range: 21 to 85 years). Thirteen patients underwent unilateral procedures (5 on the right and 8 on the left), and three patients underwent staged bilateral procedures. Six patients (6/16) had previously undergone back surgeries. We have followed up our patients for at least 12 months (12-36 months, mean 20.6 months) after this procedure. Needle puncture was possible without difficulty in all patients. There was no operative death. Transient back pain or soreness was seen in most patients, with recovery in the following 3 days. One patient with plantar hyperhidrosis achieved persistent anhidrosis. Another patient had neuritic pain in the genitofemoral distribution and he recover in a month. Other reported complications were not seen. Six limbs had very satisfied, 7 had satisfied, 4 had fair, and none had unsatisfied early outcome. Regarding late outcome, 9 limbs were very satisfied, 7 were satisfied, 3 were fair, and none was unsatisfied with this procedure. In summary, we describe a simple and modified technique guided by CT to localize the acute placement of the needle tip prior to injection of a neurolytic agent. It is a safe, effective, reproducible and reliable technique and accurate needle placement is readily demonstrated using CT scan.