Phyo Kim

Delayed myelopathy induced by chronic compression in the rat spinal cord

Cervical myelopathy is a common cause of neurological disability among the elderly; however, the exact mechanism for the insidious and progressive deterioration remains to be elucidated. To study the pathophysiology, we developed a simple experimental model reproducing the course. In rats, a thin sheet of expanding polymer was implanted microsurgically underneath the C5‐C6 laminae. In the control group, the polymer sheet was removed immediately. Changes in motor functions were monitored for 25 weeks after the operation, with voluntary exercise activity measured by odometer attached to revolving cages, and forced running capability measured by duration of exercise on a rotating treadmill. Motor neurons were counted stereologically in continuous sections. In the compression group, the forced running capability deteriorated after a latent period of 17 weeks and progressively thereafter. In the control group, it stayed unchanged throughout 25 weeks. Course of the voluntary exercise was comparable between the groups. Motor neuron density in the compression group decreased significantly in 9 weeks (−20.3%) and 25 weeks (−35.5%), but not in 1 or 3 weeks. This practical model properly reproduces characteristic features of the clinical cervical myelopathy, with progressive motor disturbance after a latency and insidious neuronal loss preceding the symptoms. Ann Neurol 2004

Proper management of the rotational vertebral artery occlusion secondary to spondylosis

A 66-year-old man with cervical spondylosis noticed severe vertigo when turning his head to the right. He underwent subclavian arteriography elsewhere, which showed a block of the contrast medium in the right vertebral artery (VA) at the C5/6 level when the patient turned his head to the right. After referral to our institute, however, postcontrast CT scan revealed an attenuated shadow of the venous plexus around the right VA at the C3/4 level. Repeated selective angiography with rotation of the head after visualization of the entire VA verified the level of obstruction to be at C3/4. Resection of the C4 transverse process through an anterior approach with drilling of the C3/4 spondylotic spur of the uncinate processi completely resolved the arterial impingement and the symptom. When evaluating rotational VA occlusion, dynamic angiography with selective catheterization is essential in determining which level is affected. The postcontrast CT scan is also useful because it suggests the level even without head rotation.

Combination chemotherapy using carboplatin (JM-8) and etoposide (JET therapy) for recurrent malignant gliomas: a phase II study.

Summary. Background: To study efficacy and safety of chemotherapy using carboplatin (JM-8) and etoposide (“JET” therapy) for the treatment of recurrent malignant glioma, a phase II study was conducted. Tumour control, survival time, and toxicity/side effects were assessed in patients with recurrent malignant glioma which failed to respond to a postoperative combined auxiliary therapy comprising of IFN-β, ACNU and radiation. Methods: Twenty-eight patients, fourteen with anaplastic astrocytoma (AA) and fourteen with glioblastoma (GB) were included in this study. The JET regimen consists of the intravenous administration of carboplatin (300 mg/m2) on day 1 and etoposide (60 mg/m2) on day 1 to 5, repeated every 6 weeks. Findings: Following the therapy, we observed partial response (PR) in five (36%) of 14 patients with AA and two (14%) of 14 with GB, and stabilization of the disease (SD) in six (43%) in each group. The mean survival/survival after recurrence was 51 months/25 months in the AA group, and 17/9 in the GB group. Interpretations: These results compare favorably with the natural course of recurrent malignant glioma. JET shows signs of efficacy in patients with recurrent malignant glioma, and a randomized trial comparing it to standard therapy is warranted.

Neuromuscular choristoma of the oculomotor nerve: case report.

OBJECTIVENeuromuscular choristomas (NMC) are rare benign tumors of the peripheral nerves. We report an NMC affecting the oculomotor nerve. CLINICAL PRESENTATIONAn 18-year-old girl presented with long-standing intermittent retro-orbital pain and oculomotor paresis. Magnetic resonance imaging scans demonstrated a small nodular lesion on the left oculomotor nerve, similar to the findings for a schwannoma. INTERVENTIONThe tumor was resected with the parental oculomotor nerve, which was reconstructed using a peroneal nerve graft. Postoperatively, the patient became pain-free, and her oculomotor function partially recovered. Histologically, the lesion consisted of well-differentiated smooth muscle fibers intermingled with mature nerve elements consistent with the diagnosis of an NMC, although the possibility of leiomyoma in this rare location was not excluded completely. CONCLUSIONNMC may need histological confirmation for diagnosis if they occur in the intracranial space. The resection is feasible, and the function of the affected nerve can be at least partially restored with the nerve reconstruction.

Comparison of numerical change of epidermal growth factor receptor gene among pre- and postradiation glioma, and gliosis, and its clinical use

Surgery with following chemoradiotherapy is the mainstream glioma treatment. In the course of postradiation events, however, it is sometimes difficult for neurosurgeons, radiologists, and pathologists to discriminate tumor recurrence from radiation necrosis. The epidermal growth factor receptor (EGFR) gene, on chromosome 7, is known to gain in copy number frequently in high-grade gliomas. The authors applied the fluorescence in situ hybridization (FISH) method to observe the genes numerical status in pre- and postradiation glioma samples to elucidate whether this technique is useful in the discrimination of glioma recurrence from radiation necrosis. When 15 postradiation glioma samples and 4 postradiation nonglioma samples were tested, all the recurrent glioma tissue harbored numerical aberrations of the gene, whereas no abnormality could be observed in necrosis or in nonglioma gliosis. FISH could even prove a residual glioma cell in a gliotic tissue taken by needle biopsy after gamma-knife radiosurgery, which had been executed on a supposed metastatic brain tumor. FISH is considered to be of help in accurate diagnosis, especially when the usual histopathological diagnosis is difficult because of radiation effects or small sample size.

Newly designed ergonomic surgical binocular telescope with angulated optic axis.

ObjectIVE Magnification by surgical loupes has the distinct merits of agility and nimbleness in observation, a wide stereo base effectuating superior depth sensation, and light augmentation by an objective lens that is larger than the pupil. However, continuous use of these loupes causes neck strain for surgeons as a result of flexion posture and fatigue. To minimize the strain and fatigue and maximize the advantages and performance of binocular telescopes, we have developed a novel optical design. METHODS To allow observation of the operative field with the surgeons neck and eye in a straight position, the light path of the telescopes was angulated downward with roof prisms. For maximum image quality, Keplerian real-image optics were adopted. RESULTS The optics, finishing of the lens, and assembly were perfected through practical trials of more than 500 procedures over a period of 3 years. CONCLUSION The new ergonomically designed optics provide excellent image quality comparable to standing microscopes in the low to medium range of magnification, while effectively reducing the neck flexion of surgeons working in the operative field below and relieving the surgeons fatigue during hours of continuous use.

Effect of Myoarchitectonic Spinolaminoplasty on Concurrent Hypertension in Patients With Cervical Spondylotic Myelopathy

Objective When treating patients with cervical spondylotic myelopathy (CSM), we often note amelioration in concomitant hypertension after surgery. To assess the effects of surgery and the mechanisms thereof, blood pressure (BP) and parasympathetic nervous activity were monitored prospectively in CSM patients undergoing surgery. Methods Sixty-eight consecutive CSM patients who underwent surgery with myoarchitectonic spinolaminoplasty were enrolled. BP and electrocardiography were recorded preoperatively and at 1, 3, and 6 months postoperatively. Forty-six patients completed the scheduled follow-ups and were analyzed. Preoperatively, 17 had a mean BP higher than 100 mmHg (the HT group) and 12 had hypertension despite taking medication (the HT-refractory group). To evaluate alterations in parasympathetic function, the coefficient of variation of the RR interval (CVRR) was evaluated. Results A significant BP reduction was observed in the HT group 6 months after surgery, but not in the normotensive group (n=29). The effect was more remarkable in the HT-refractory group. A transient BP increase at 1 and 3 months after surgery was observed in all groups. Comparisons were made between groups classified by age (over 65 years or younger than 60 years) and the presence or absence of an intramedullary hyperintense T2 signal on magnetic resonance imaging, but no significant differences were detected. Measurements of CVRR did not significantly differ between the groups over the course of follow-up. Conclusion Hypertension coexisting with CSM can be ameliorated after surgical treatment. The effect is likely to be mediated by moderation of sympathetic activity, rather than parasympathetic activation. We believe that a combination of adequate decompression of the spinal cord and relief from musculoskeletal stresses effectuate this moderation.