Cervical spondylosis is a chronic degenerative change of the cervical spine, which is promarily caused by intervertebral disc decay. In cervical spondylosis, neurological symptoms are caused by various combinations of 5 factors : developmental canal stenosis, osteophytes, kyphotic deformity, instability and ossification of posterior longitudinal ligament(OPLL). To determine an operative approach, these 5 factors should first be considered. The author recommends laminoplasty and anterior interbody fusion using hydroxyapatite ceramics as implants because of the simplicity of the procedure and the lack of donor site morbidity. However, long-term postoperative follow-up is required because kyphotic deformity and/or restenosis may occur after laminectomy or laminoplasty and adjacent-segment disease may occur after anterior interbody fusion.

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Cushing syndrome can divided into 4 categories, i. e., pituitary adenoma, ectopic ACTH secreting tumor, adrenal adenoma and adrenal cancer. Among them, the former 2 are classified as ACTH-dependent lesions. Endocrinological examinations, such as dexamethasone suppression test and CRH stimulation test, cannot clearly differentiate these 2 lesions because of unusual responses seen in patients with each disorder. High resolution MRI can detect a tiny pituitary lesion of 2 mm in diameter. However, Cushing's disease may be caused by a much smaller adenoma which cannot be visualized by current diagnostic imaging techniques. In addition, there are many kinds of subclinical lesions found in the autopsied pituitary glands. These incidentalopmas may become false positive results in the diagnosis using MRI. In order to prove the hypersecretion of ACTH from the pituitary gland, inferior petrosal sinus(IPS)sampling has been used for almost 40 years. This technique requires bilateral simultaneous catheterization to IPS and also CRH stimulation during the sampling. In 1993, we newly developed the method of cavernous sinus(CS)sampling which could provide a sufficient c/p(central/peripheral)ratio in almost all patients with a pituitary lesion. Our surgical indication for patients with ACTH-dependent Cushing's syndrome mainly based on the result of CS sampling, When the sampling and MRI are both positive, we select transsphenoidal surgery(TSS)without hesitation. If the sampling is positive but MRI is negative, we treat the patient with adrenal enzyme blockers'such as trilostane, metylapone for several months. MRI is performed every 3 month during this"chemical Nelson"treatment. The patient with negative sampling result will be referred to the endocrinologist.

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The purposes of this study were (1)to evaluate long-term results after surgical treatments for craniosynostosis(CS)and (2)to identify factors that might influence these results. From April 1, 1984 to December 31, 1998, 56 children with craniosynostosis were treated by craniofacial procedures mainly fronto-orbital advancements with cranial remodeling in Saitama Children's Medical Center. Diagnoses included isolated CS(32 cases)and syndromic CS(24 cases). Long-term surgical results of these cases and problems related surgical managements were analyzed at the end of follow-up period. Follow-up ranged from 2 to 15 years(mean 8.8 years). Surgical results were graded according to the grading system reported by Wagner JD et al(1995). In these results, better morphological and functional results were obtained in cases with isolated CS than syndromic CS. The factors which most greatly influenced surgical results and the need for reoperation were the type of CS and the timing of initial operations. The result of the syndromic cases operated before the age of 12 months was poor and the rate reoperation was extremely high in these cases. On the contrary, aesthetic or functional results of isolated CS treated in the first 12 months of life were favorable. In the future it is necessary to carry out the early diagnosis and early surgical therapy based on the craniofacial principles to improve the surgical results of isolated CS. In addition to these efforts, new therapeutic technologies should be introduced to the treatments of syndromic craniosynostosis or craniofacial dysostosis syndromes.

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We have been performing experimental and clinical studies on intraoperative monitoring of the cranial nerves. In the present manuscript, methods of intraoperative monitoring of the upper cranial nerves(I〜VI)are reported. Olfactory nerve : Olfactory evoked potentials(OEPs), obtained by electrical stimulation of the olfactory mucosa, were recorded in dogs and humans. In clinical cases, OEPs correlate well with the olfactory function. This method is useful for intraoperative monitoring of olfatory functions. Optic nerve : In dogs, 2 silver ball electrodes were placed on the optic nerve adiacent to the apex of the orbit for electrical stimulation, and another one near the chiasma for recording. Optic nerve evoked potentials(ONEPs)were recorded. Graded transection of the nerves reduced the amplitudes. In clinical cases, ONEPs have good correlation with the optic function. Oculomotor, trochlear and abducens nerves : In dogs, evoked potential elicited by electrical stimulation of the nerves were recorded from surface electrodes around the orbit. Experimental study revealed that most component of the action potentials recorded from surface electrodes originated from EMGs of extraocular muscles. This technique provides noninvasive recording in intraoperative monitoring for ocular motor nerve function. This method is useful to detect the oculomotor, trochlear and adducens nerves. Trigeminal nerves : Motor root of the trigeminal nerve was electrically stimulated and the EMG of the masseter muscle was recorded. This method is useful to distinguish the trigeminal nerve from the facial nerve. At present, these monitoring methods are useful for detecting the nerves and estimating rough functions of the cranial nerves, however, precies correlation of the functions and the findings of intraoperative monitoring should be further studied.

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Background : Cerebral vasospasm(VS)is a major cause of neurological deterioration in patients with subarachnoid hemorrhage(SAH). Previous studies have shown a markedly high level of thrombin activity in the cerebrospinal fluid(CSF)of patients with SAH. This study was undertaken to confirm that previously reported correlation between VS and thrombin, by administering the thrombin-inhibitor"argatroban". Methods : Adult mongrel dogs received autogenous arterial blood injections in the cisterna magna(0.5ml/kg), and were given continuous intrathecal infusion of argatroban using osmotic pump(argatroban group). As controls, other dogs received ringer's solution alone. Angiography was performed before surgery and again, seven days after the treatment. Histological evaluation of the blood vessels and inflammatory cells in the subarachnoid space was performed on day seven. Results : The mean diameter of the basilar artery on day seven was significantly larger in the argatroban group(p=0.0191). There were also fewer inflammatory cells in the subarachnoid space in argatroban group(p=0.0079). Conclusion : Thrombin plays an important role in the mechanism of VS following SAH, and its inhibition may open a therapeutic window to VS.

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In the field of neurosurgery, surgical tracheostomy is an indispensable treatment for those to the patients with respiratory insufficiency. Percutaneous tracheostomy was recently developed as a less invasive alternative method. During the last 15 months, we performed tracheostomies in 34 patients using percutaneous tracheostomy Kit. As a result. all of the percutaneous tracheostomies were performed within 5 minutes and without incident. All of the cases were free of complications except one case of slight subcutaneous emphysema. In 3 cases, a bronchofiberscope was used to observe the bronchial wall during this procedure. In conclusion, we confirmed that this procedure was proved to be minimum invasive. However, it should be performed under preparation for surgial procedure by any chance to be absolutely safe, preparations for surgical intervention should be made.

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Vertex epidural hematoma(VEDH)account for only 2 to 8% all of cases of acute epidural hematoma. We present 2 cases of VEDH and discuss the problems of treatment. The diagnosis of VEDH is often missed with conventional horizontal computed tomography(CT)and is complicated in cases with accompanying cervical spinal cord injury. Magnetic resonance imaging is superior to CT for diagnosing VEDH. Problems of surgical treatment include the position of the patient and the placement of skin incisions. Because hematomas can expand during the radiologic evaluation or during surgery, skin incisions and the craniotomy must be carefully designed with this possibility in mind. Also, it is better not to remove the bone above the sagittal sinus because it is useful if there is an associated sinus injury.

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The use of vascular prostheses is relatively unocommon in the neurosurgical field. We report a case of carotid artery replacement using an expanded polytetrafluoroethylene(ePTFE)synthetic graft in a patient with thyroid cancer. A 61-year-old woman presented with a cervical fist-sized mass infiltrated into the skin of her neck. Computed tomography scanning(CT)and magnetic resonance imaging(MRI)revealed an irregular sharp mass lesion with calcification. The left common carotid artery was encased in the tumor. Radical nock dissection and carotid artery reconstruction were performed. The tumor and the affected portion of carotid artery(6cm in length)were resected en masse, and the resected carotid artery was replaced with an artificial vessel(ringed ePTFE). The postoperative course was uneventful, and good patency and no tumor recurrence were confirmed 1 year after the operation.

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