Teruhide Takagi

Adrenomedullin reduces ischemic brain injury after transient middle cerebral artery occlusion in rats.

Summary Background. The effect of adrenomedullin, a vasodilatory peptide on transient middle cerebral artery (MCA) occlusion was investigated in rats. Methods. Transient MCA occlusion for 2 hours was made by using the intra-arterial suture method, followed by reperfusion. Findings. An intravenous infusion of adrenomedullin (1 μ g/kg/min) from one hour before ischemia to one hour after ischemia significantly reduced the infarct size and improved neurological deficits (p<0.05), without affecting systemic blood pressure or other physiological parameters. The infarct size was reduced with adrenomedullin by 25.4±12.7%, 31.3±5.8%, 31.6±6.1% respectively at the coronal level 6, 8 and 10 mm posterior from the frontal pole. Adrenomedullin also significantly inhibited the increase in myeloperoxidase (MPO) activity in the MCA area of the ischemic hemisphere after 22-hour reperfusion (control: 0.205±0.054 unit/g wet tissue, adrenomedullin group: 0.047±0.009 unit/g wet tissue, p<0.0001). Interpretation. These data suggest that adrenomedullin reduces acute ischemic brain injury and one of is neuroprotective mechanisms may be derived from inhibition of the infiltration of neutrophils into the ischemic tissue.

En Bloc Laminoplasty Performed with Threadwire Saw: Technical Note

OBJECTIVE To introduce a method for a simple, nonexpansive laminoplasty that can be performed with a threadwire saw (T-saw) after en bloc laminotomy has been performed. The method can be applied along the entire spinal region, including the thoracic and lumbar spine. METHODS An en bloc laminotomy of trapezoid shape at the cross section is performed bilaterally at the junctional area of the lamina and facet joint with a thin, flexible T-saw, while preserving the supraspinous, interspinous, and interlaminar ligaments. After the intradural procedure has been performed, the laminar flap is replaced in its original site and fixed with 1-0 nylon sutures, resulting in the complete reconstruction of the posterior supporting elements of the spinal column. RESULTS En bloc laminoplasty was performed on 16 patients via a T-saw; most of the patients had intradural spinal tumors. The patients did not need their spinal canals to be enlarged after the intradural procedure had been performed. The follow-up period ranged from 2 to 40 months (mean ± standard error, 22.6 ± 3.4 mo). The laminoplasty was performed from the upper cervical to the sacral regions, although the most frequently operated level was the lower thoracic level. Two-level laminoplasty was performed in 12 patients, and three-level laminoplasty was performed in four. The laminoplasty was done safely and without any complications, except in one patient, who experienced thoracic root injury from a T-saw that was accidentally inserted anterior to the roots. No spinal column deformity or sinking of the replaced laminar flap was noted during the follow-up period; patients were assessed at follow-up via radiographs or computed tomographic scans. Computed tomographic scans obtained later indicated that bony fusion occurred at the cutting edges 1.0 to 4.0 months after surgery (mean, 1.90 ± 0.34 mo). CONCLUSION Simple en bloc laminoplasty performed with a T-saw is a useful, safe procedure that can be used to reconstruct the posterior spinal elements throughout the whole spinal region after the intradural procedure has been performed.

A simple technique for expansive suboccipital cranioplasty following foramen magnum decompression for the treatment of syringomyelia associated with Chiari I malformation

The benefits of osteoplastic suboccipital craniotomies over the traditional suboccipital craniectomies have been recognized. We describe a simple method of expansive suboccipital cranioplastic craniotomy using a free bone flap and report satisfactory clinical results in 16 patients with syringomyelia associated with Chiari I malformation. A free suboccipital bone flap is created from the rostral part of the occiput by placing two to four burr holes and connecting them with a craniotome. The posterior bony margin of the foramen magnum and the posterior arch of C1 are removed thereafter. Then dural plasty using a patch graft of dural substitutes is performed. The expansive suboccipital cranioplasty is performed by positioning the free bone flap caudal to the original location and fixing it with titanium miniplates to construct a bony frame to cover the foramen magnum. The rostral part of the cranial defect is filled with bone chips created during the craniotomy. Sixteen patients underwent this procedure. There was no operative mortality and no major complication, such as persistent pseudomeningocele. Preoperative symptoms improved significantly in all patients except for one who had persistent dysesthetic pain. Our simple method of expansive suboccipital cranioplasty for the treatment of syringomyelia associated with Chiari I malformation proved useful and achieved satisfactory long-term results.

Osteoplastic anterolateral vertebrotomy without fusion for multilevel cervical ossification of the posterior longitudinal ligament

OBJECTIVE To introduce a new method for osteoplastic anterolateral vertebrotomy without fusion to resect multilevel cervical ossification of the posterior longitudinal ligament. METHODS A multilevel vertebral column graft containing portions of the intervertebral discs is cut with a microsurgical saw from the anterolateral part of the vertebra via a thin lateral gutter placed in advance. A sufficiently wide oblique operative field is provided for resection of the ossified ligament with this method, and only a narrow bony defect remains after simple replacement of the vertebral graft. Postoperatively, patients are allowed to walk, usually within 2 to 3 days, wearing simple cervical collars. RESULTS Twelve patients underwent resection of the ossified ligaments in two to five vertebral bodies. Clinical results were satisfactory except in one patient, who died as a result of a pulmonary embolism that occurred 10 days after surgery. In all of the other patients, the vertebral column grafts were fused within a few months, and there were no graft-related problems. Postoperative lateral radiographs revealed that cervical alignment was preserved, with intervertebral mobility at the operated segment in flexion-extension views. CONCLUSION The osteoplastic anterolateral vertebrotomy method provided a sufficiently wide operative field for satisfactory resection of multilevel cervical ossification of the posterior longitudinal ligament, simplifying graft replacement and postoperative patient care. The cervical alignment was preserved.

Soluble gp130 regulatess interleukin-6 in cerebrospinal fluid after subarachnoid haemorrhage

Background Interleukin-6 (IL-6) is a proinflammatory cytokine reported to play an important role in induction of cerebral vasospasm after subarachnoid haemorrhage (SAH). Soluble gp130 (sgp130) and soluble IL-6 receptor (sIL-6R) are known to act as signal transducing receptors of IL-6, the former as an antagonist and the latter as an agonist. However, there have been no reports concerning regulation of the IL-6 signalling pathway in cerebrospinal fluid (CSF) after SAH. Mehods Concentrations of IL-6, sgp130 and sIL-6R were measured serially until day 14 in CSF from nine patients with SAH. CSF samples obtained from patients suffering from unruptured aneurysm were used as controls. Colocalisation of IL-6 and sgp130 in CSF on day 1 was further examined by immunoprecipitaiton. Results Concentrations of IL-6 in CSF increased immediately after the onset of SAH and remained chronically elevated over control values. Both sgp130 and sIL-6R also exhibited increased on day 1, followed by a decrease limited to the gp130 case after day 5. Sgp130 coimmunoprecipitated with IL-6 in CSF on day 1 after SAH. Conclusions Our findings suggest that sgp130 regulates IL-6 signalling as an antagonist in CSF immediately after SAH. As the concentration of sgp130 decreases after day 5, IL-6 signals might then be more easily transmitted, presumably resulting in cerebral vasospasm.

Elevation of Nitric Oxide Metabolites in the Cerebrospinal Fluid of Patients with Moyamoya Disease

Summary Background. To investigate whether nitric oxide (NO) contributes to formation of abnormal collateral circulation in patients with moyamoya disease. Methods. Cerebrospinal fluid (CSF) samples were obtained from the subarachnoid space of the Sylvian fissure during combined bypass surgery for moyamoya disease and kept frozen until NO metabolites, nitrate and nitrite, were measured using a Griess method. Results. Compared with control CSF obtained from 18 patients with hemifacial spasm, unruptured aneurysm, etc., concentrations of NO metabolites in 26 CSF samples of 18 patients with moyamoya disease were significantly higher (mean±SE; 17.6±1.2 vs. 10.5±1.0 μM, p<0.01). In eight patients, the CSF samples from both the first and second operation could be obtained. NO metabolite concentrations (20.5±2.3 μM) in CSF obtained from the first surgery decreased to 15.7±1.8 μM (p<0.01) in CSF obtained from the second, contralateral procedure. The cases of moyamoya disease with greater development of moyamoya vessels at angiographic stage 3 and 4 tended to show higher concentrations of NO metabolites than cases at earlier or later stages with a few moyamoya vessels. Interpretation. Nitric oxide concentrations in CSF are chronically elevated in moyamoya disease, probably reflecting development of abnormal collateral circulation. i.e. moyamoya vessels. Vascular bypass surgery can reduce abnormal collateral circulation with reduced production of nitric oxide.