Spino-bulbo-spinal pathway mediating vagal modulation of nociceptive-neuroendocrine control of inflammation in the rat.
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Stimulation of nociceptors by intradermal capsaicin produces depression of bradykinin (BK)-induced synovial plasma extravasation (PE) that is markedly enhanced by subdiaphragmatic vagotomy. This depression is mediated by the adrenal medullae, a propriospinal pathway between the afferent nociceptive input and preganglionic neurones projecting to the adrenal medullae, and a spino-bulbo-spinal pathway. Here we investigated the role of spinal ascending and descending pathways in the interaction between noxious and vagal afferent inputs, leading to inhibition of BK-induced PE mediated by the adrenal medullae. Nociceptors in the paw were activated by capsaicin and depression of BK-induced PE was measured in rats with intact or cut subdiaphragmatic vagus nerves. After cutting the dorsolateral funiculus (DLF) contralateral to the stimulated hindpaw (segmental level C5/C6 and T8/T9), depression of BK-induced PE was weak or absent both in rats with intact vagus nerves and in vagotomised rats, suggesting that an ascending excitatory pathway was interrupted. After cutting the DLF ipsilateral to the stimulated hindpaw, depression of BK-induced PE was already markedly enhanced, even in the absence of vagotomy. Ipsilateral DLF lesion (L2/L3) below the level of the spinal output to the adrenal medullae produced the same effect, suggesting interruption of a descending inhibitory pathway that relays the effect of vagal activity to the level of the capsaicin-induced nociceptive input. Contralateral and ipsilateral hemisection of the spinal cord (C5/C6) produced the same changes as the corresponding DLF lesions. Ipsi- or contralateral lesion of the dorsal funiculus at the spinal level T8/T9 had no effect on depression of BK-induced PE generated by cutaneous noxious stimulation of the forepaw. We suggest that noxious stimulation activates an ascending pathway of the spino-bulbo-spinal excitatory circuit which projects through the DLF contralateral to the nociceptive input, and that the inhibitory pathway which is activated by vagal afferent activity projects through the DLF ipsilateral to the nociceptive input. (+info)
Atlas hypoplasia manifesting as myelopathy in a child--case report.
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A 14-year-old Japanese boy presented with myelopathy due to atlas hypoplasia with complete posterior arch. Decompressive laminectomy of the atlas produced good neurological recovery, and follow-up T2-weighted magnetic resonance imaging showed disappearance of spinal cord edema. Congenital atlas stenosis may be symptomatic even in children, with no accompanying cervical spondylotic change. Such cases have previously occurred only in Asian adults. A radiological study of the patient's brother showed median cleft formation of the posterior arch of atlas, indicative of a wide spectrum of atlas anomalies and a possible genetic relationship between these anomalies. (+info)
Intramedullary enterogenous cyst presenting with spastic paraparesis during two consecutive pregnancies: a case report.
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A 35 year old woman presented with two episodes of spastic paraparesis, occurring in the third trimester of two consecutive pregnancies. The neurological symptoms seemed to be caused by an intramedullary cyst in the thoracic spinal cord. The cyst was subtotally removed and histopathologically diagnosed as enterogenous cyst. Other congenital abnormalities were absent. The peculiar timing of the clinical manifestation of an intramedullary cyst has not been described before. An unequivocal explanation for this phenomenon is missing, but several factors related to pregnancy that may play a part are discussed. (+info)
Mechanical and histological analysis of bone-pedicle screw interface in vivo: titanium versus stainless steel.
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OBJECTIVE: To investigate the differences in bone interface between titanium and stainless steel pedicle screws in the lumbar spine. METHODS: Eighteen adult mini-pigs that underwent total laminectomy, posterolateral spinal fusion (L4-L5) were randomly selected to receive stainless steel (9) or titanium pedicle screw devices (9). In both groups, the devices were CCD (Sofamore Danek) type with the same size and shape. The postoperative observation time was 3 months. Screws from L4 were harvested along their long axis of pedicle for histomorphometric study. Bone-screw interface and bone volume from thread were examined using linear intercept techniques. Mechanical testing (torsional test and pull-out test) was performed on the screws from L5. RESULTS: The titanium screw group had a significantly higher maximum torque (P < 0.05) and angle related stiffness (P < 0.05) measured by torsional test. In the pull-out tests, no differences were found between the two groups in relation to the maximum load, stiffness and energy to failure. Direct bone contact with the screw in percentage was 29.4% for stainless steel and 43.8% for titanium (P < 0.05). No differences in the bone purchase between the vertebral body part and pedicle part were found. CONCLUSION: Pedicle screws made of titanium have a better bone-screw interface binding than screws made of stainless steel. Torsional tests are more informative for bone-screw interface study. Pull-out tests seem less valuable when comparing bone purchase of screws made from different materials. (+info)
Development of new surgical treatments in spinal surgery: expansive open-door laminoplasty and percutaneous nucleotomy.
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The outstanding achievements of two renowned spine surgeons, who are alumni of the Department of Orthopaedic Surgery, Keio University, are described. Anterior decompression followed by fusion and laminectomy had been the standard techniques for cervical myelopathy due to disc herniation, spondylosis and ossification of the posterior longitudinal ligament. However, both techniques were not without certain comorbidities. Dr. Kiyoshi Hirabayashi devised an epoch-making expansive open-door laminoplasty, in which both sufficient posterior decompression and preservation of cervical stability are achieved simultaneously with reduced risk of such complications. Dr. Sadahisa Hijikata is the pioneer of a totally new concept treatment, percutaneous nucleotomy, for lumbar disc herniation, one of the most prevailing diseases that cause low back pain and sciatica. He devised this technique to avoid prolonged conservative treatment with associated suffering of the patients and to minimize the chance of morbidity that is occasionally associated with an open surgery. This technique, together with chemonucleolysis, has led to the establishment of intradical or intermediate treatments which lie between conservative and surgical treatments. Both techniques have not only brought the relief of pain and suffering in numerous patients, but have also opened the door to the development of many new modified procedures and technologies. Most importantly, these two techniques still remain as the most viable choice among various similar modifications. The rationale, indictions, technique as well as the present status and future perspective for these two innovative yet fundamental techniques are introduced and discussed. (+info)
The historical development of dural substitutes and the process of regeneration of dura mater are reviewed. Lyophilised human cadaver dura mater has been implanted intracranially in baboons and the graft shown to be incorporated with vascularisation but with ossification. In the human, lyophilised dura mater used as a dural substitute also becomes a viable tissue but without ossification. A retrospective study of its use in 100 neurosurgical patients showed a low complication rate and it is suggested that there are occasions when the ready availability of lyophilised dura mater, without the need for a further incision, makes it the dural substitute of choice. (+info)
Complications of lumbar drainage after thoracoabdominal aortic aneurysm repair.
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OBJECTIVES: Paraplegia remains a frequent complication of thoracoabdominal aortic aneurysm (TAAA) repair. Many adjunct therapies have been developed to address this complication. Lumbar drainage is frequently used in an attempt to decrease intrathecal pressure and improve intramedullary perfusion pressure. The effectiveness of this therapy is unclear, and the complications of lumbar drainage used for this indication are unknown. We present a case of intraspinal hematoma with significant neurologic deficit after TAAA repair and review the associated complications of lumbar drains placed for TAAA. METHODS: The charts of all patients undergoing operations for TAAA repair were reviewed. Patients who underwent perioperative placement of a lumbar drain were included regardless of aneurysm type or etiology. Demographics, Crawford grade, and perioperative parameters and complications were reviewed. RESULTS: Sixty-five patients underwent TAAA repair with 62 (95%) receiving a preoperative lumbar drain. There were two (3.2%) intraspinal hemorrhagic complications, including one patient with a poor neurologic outcome. No infections or other complications directly related to drainage were identified. Multivariate logistic regression analysis failed to demonstrate a significant association between lumbar drain complications and perioperative and intraoperative parameters such as blood loss or hypotension, level of drain placement, and Crawford grade. CONCLUSIONS: Lumbar drainage is a frequent adjunct to TAAA repair. However, placement of the drain itself can be associated with significant complications whose aggravating factors may be unidentifiable. Complications resulting from lumbar drainage should be considered in any patient who has postoperative lower extremity neurologic deficits. (+info)
Purulent and constrictive pericarditis arising from a staphylococcal lumbar infection.
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A 78-year-old man was admitted to the hospital for evaluation and treatment of anasarca secondary to staphylococcal purulent pericarditis. One month earlier he had undergone a lumbar laminectomy that was complicated postoperatively by a lumbar abscess that was not clinically apparent. The infection subsequently spread to the pericardium. Despite aggressive therapy that included therapeutic pericardiocentesis, drainage of pericardial fluid, and prolonged intravenous antibiotic therapy, the patient returned 2 weeks after discharge from the hospital with complicating constrictive pericarditis. Pericardiectomy was performed, resulting in complete relief of the patient's symptoms. (+info)