The predictive performance of propofol target-controlled infusion during robotic-assisted laparoscopic prostatectomy with CO2 pneumoperitoneum in the head-down position

PURPOSE

Propofol clearance can be reduced when cardiac output (CO) is decreased. This clearance reduction may alter the pharmacokinetics of propofol and worsen the predictive performance of target-controlled infusion (TCI) of propofol. The head-down position (HDP) and CO₂ pneumoperitoneum, which are required for robotic-assisted laparoscopic prostatectomy (RALP), may cause changes in CO. We investigated the predictive performance of propofol TCI during CO₂ pneumoperitoneum in patients who underwent RALP in the HDP.

METHODS

Fifteen male patients received propofol TCI using the Diprifusor model. Propofol concentrations were measured at seven time points: (T1) 15 min after anesthesia induction; (T2) before the insufflation; (T3, T4, and T5) 15, 60, and 90 min, respectively, after insufflation in the HDP; (T6) before the release of pneumoperitoneum in the HDP; and (T7) 15 min after the release of pneumoperitoneum in the supine position. Cardiac index (CI) was assessed using an arterial pulse contour CO monitor. The predictive performance of propofol TCI was evaluated by calculating the performance errors (PE) in propofol concentrations for each data point. The relationship between CI and PE was examined. Median PE (MDPE) and median absolute PE (MDAPE) were calculated as measures of bias and accuracy, respectively.

RESULTS

A total of 104 blood samples were analyzed. There was significantly negative correlation between CI and PE. The predictive performance of propofol TCI during pneumoperitoneum in the HDP was acceptable (MDPE = - 1.5% and MDAPE = 18.8%).

CONCLUSION

The predictive performance of propofol TCI during RALP with CO₂ pneumoperitoneum in the HDP was acceptable.

Ultra-early MRI showing no abnormality in a fall victim presenting with tetraparesis

STUDY DESIGN

Case report.

SETTING

Department of Neurosurgery, Sapporo Azabu Neurosurgical Hospital and Department of Neurosurgery, Hokkaido University Graduate School of Medicine, Sapporo, Japan.

CASE REPORT

A patient presented to us with complete C4 tetraplegia after a 3-m fall. MRI performed 120 min after his fall showed spinal canal stenosis due to disk protrusion at the C3/4 level without spinal cord signal changes on T1- and T2-weighted images. He underwent laminoplasty between C2 and C6. Intraoperative ultrasound, performed 6 h after his fall, disclosed a hyperechoic lesion at the C3/4 level of the cervical cord; postoperative T2-weighted MRI, obtained at 8 h after his fall, showed high intensity at the same level.

CONCLUSION

In patients with cerebral infarction, approximately 6 h between the insult and the acquisition of T2-weighted MRI are required to detect signal changes. We postulate that the time course on MRI scans obtained immediately after spinal cord injury is similar in patients with spinal cord injury and cerebral infarction and suggest that the absence of spinal cord abnormalities in the ultra-early post-injury stage is not always predictive of a good prognosis.

Anterior decompression of the atlantoaxial vertebral artery to treat bow hunter's stroke: technical case report

OBJECTIVE AND IMPORTANCE

Bow hunter's stroke is a symptomatic vertebrobasilar insufficiency caused by stenosis or occlusion of the vertebral artery at the C1C2 level with head rotation. No case of anterior decompression of the vertebral artery for surgical treatment of bow hunter's stroke has been reported.

CLINICAL PRESENTATION

A 47-year-old male patient presented with repeated episodes of unconsciousness caused by turning his head approximately 40 degrees to the right; he recovered consciousness within approximately 10 seconds after his head was returned to the neutral position. Angiography revealed an occluded right vertebral artery and temporary occlusion of the left vertebral artery, at the level of the C2 transverse foramen, when the patient's head was turned approximately 40 degrees to the right.

INTERVENTION

Anterior decompression of the left vertebral artery at the transverse foramen of the axis was performed. Postoperative angiography demonstrated sufficient flow in the left vertebral artery even when the neck was rotated.

CONCLUSION

The patient was discharged without neurological deficits. We demonstrate that simple surgical untethering of the vertebral artery at the transverse foramen of the axis is an effective method of treatment that avoids the limitation of head rotation. The advantage of this procedure is that it does not result in postoperative restriction of the patient's neck movements. The anterior approach, with decompression of the transverse foramen of the axis, in the present case provided adequate exposure of the vertebral artery and resulted in a satisfactory outcome.

Evolution of left ventricular involvement in arrhythmogenic right ventricular cardiomyopathy

Left ventricular (LV) involvement in arrhythmogenic right ventricular cardiomyopathy (ARVC) is fairly well known, but the evolution of LV involvement during long-term follow-up has not been well documented. We describe such evolution in a patient followed for 9 years. Evolution was confirmed by a progressive perfusion defect of the LV wall in myocardial scintigrams and by the development of LV asynergy with ventricular aneurysm formation in left ventriculograms. As the right ventricle progressively enlarged, we concluded that ARVC is a diffuse and progressive myocardial disease that affects both ventricles.

Acute cervical cord injury without fracture or dislocation of the spinal column

OBJECT

It is known that the spinal cord can sustain traumatic injury without associated injury of the spinal column in some conditions, such as a flexible spinal column or preexisting narrowed spinal canal. The purpose of this study was to characterize the clinical features and to understand the mechanisms in cases of acute cervical cord injury in which fracture or dislocation of the cervical spine has not occurred.

METHODS

Eighty-nine patients who sustained an acute cervical cord injury were treated in our hospitals between 1990 and 1998. In 42 patients (47%) no bone injuries of the cervical spine were demonstrated, and this group was retrospectively analyzed. There were 35 men and seven women, aged 19 to 81 years (mean 58.9 years). The initial neurological examination indicated complete injury in five patients, whereas incomplete injury was demonstrated in 37. In the majority of the patients (90%) the authors found degenerative changes of the cervical spine such as spondylosis (22 cases) or ossification of the posterior longitudinal ligament (16 cases). The mean sagittal diameter of the cervical spinal canal, as measured on computerized tomography scans, was significantly narrower than that obtained in the control patients. Magnetic resonance (MR) imaging revealed spinal cord compression in 93% and paravertebral soft-tissue injuries in 58% of the patients.

CONCLUSIONS

Degenerative changes of the cervical spine and developmental narrowing of the spinal canal are important preexisting factors. In the acute stage MR imaging is useful to understand the level and mechanisms of spinal cord injury. The fact that a significant number of the patients were found to have spinal cord compression despite the absence of bone injuries of the spinal column indicates that future investigations into surgical treatment of this type of injury are necessary.

[Efficacy of cibenzoline for chest oppression and ventricular arrhythmia during effort and alcohol consumption in a patient with hypertrophic obstructive cardiomyopathy: a case report]

A 67-year-old man presented with chest oppression and palpitation during effort and alcohol consumption. Echocardiography demonstrated asymmetric septal hypertrophy and systolic anterior motion of the anterior mitral leaflet with a pressure gradient of 80 mmHg across the left ventricular outflow tract (LVOT), leading to the diagnosis of hypertrophic obstructive cardiomyopathy. During the treadmill exercise test, blood pressure decreased with electrocardiographic ST-segment depression and subsequent frequent premature ventricular contractions. Holter-electrocardiographic monitoring also showed ST-segment depression with premature ventricular contractions during effort and alcohol consumption. Coronary angiography showed no abnormalities and cardiac catheterization at baseline showed a systolic pressure gradient of only 2 mmHg across the LVOT. However, the gradient increased to 33 mmHg after premature ventricular contraction, 27 mmHg at Valsalva maneuver and 75 mmHg with dobutamine infusion (5 micrograms/kg/min) and disappeared with 70 mg of intravenous cibenzoline. Medication with cibenzoline (300 mg/day) for one month reduced the LVOT gradient at rest to 53 mmHg and strikingly improved symptoms and exercise tolerance and also suppressed premature ventricular contractions during exercise and alcohol consumption. We conclude that cibenzoline was effective for reduction of LVOT gradient both at rest and during exercise and alcohol consumption.

Factors in neurological deterioration and role of surgical treatment in lumbosacral spinal lipoma

The purpose of this study was to determine factors that might be involved in neurological deterioration and the role of surgical treatment in patients with lumbosacral spinal lipoma. Pre- and postoperative courses of 34 patients were retrospectively analyzed. The age at surgery ranged from 1 month to 47 years. The records of preoperative neurological status indicated that older patients had more severe deficits, while all 8 asymptomatic patients were under 5 years of age. Motor deficits were noted in 9 patients, in 7 of whom the lipoma extended cranially beyond the L5 level. Transitional-type lipomas were accompanied by more severe deficits (asymptomatic 1, symptomatic 17) than other types (asymptomatic 7, symptomatic 9). Postoperative follow-up periods ranged from 5 months to 13 years. During these periods, 7 of the 8 asymptomatic patients remained neurologically intact. Nine of the 26 symptomatic patients improved. Age, extension of the lipoma in the spinal canal and type of lipoma will influence the preoperative neurological status of the patients. Early untethering surgery is recommended in patients with large lipomas extending beyond the L5 level.

Chronological changes in MRI findings of spinal dural arteriovenous fistula

BACKGROUND

Intramedullary high-intensity changes on T2-weighted magnetic resonance images (MRI) occur in patients with spinal dural arteriovenous fistulas (AVF). Reduction of the high-intensity area after treatment has been noted; however, there are still questions about whether the change is related to preoperative clinical grade, postoperative improvement, or efficacy of treatment. This study tried to clarify the relationship between chronological changes in the high intensity area with the treatment and clinical course.

METHODS

Chronological changes in an intramedullary high-intensity area after surgery were retrospectively analyzed in recent 13 patients with spinal dural AVFs who were treated and followed by MRI.

RESULTS

Preoperative intramedullary high-intensity areas were observed on T2-weighted images in all cases. The extent of the high-intensity area correlated with preoperative neurological deficits. The intramedullary high-intensity area was reduced or diminished after successful interruption of AVFs. The high-intensity area started to decrease within 1 to 4 months after treatment in all patients, and disappeared at 2 weeks to 23 months in seven patients. The reduction may suggest interruption of the fistula and improvement of venous circulation, but was not always correlated to clinical improvement. The intramedullary high-intensity areas rapidly disappeared in two patients, but did not clearly correspond to the clinical improvement.

CONCLUSIONS

The time course of postoperative MRI changes is helpful for evaluating the efficacy of treatment after surgery for spinal dural AVFs.

[Invasive examination of cardiovascular disease]

Invasive cardiovascular examination by coronary angioscopy and by using a Doppler guide wire, a pressure guide wire and intravascular ultrasound has extensively developed. A Doppler guide wire is used for measurement of flow velocity and evaluation of coronary blood flow. Previous studies demonstrated by assessing maximum coronary vasodilatory capacity that endothelium-dependent or independent vasodilation was impaired in hypertension and hypercholesterolemia or in syndrome X. Elevation of coronary vascular resistance during coronary microvascular spasm has been verified by using a Doppler wire. A pressure guide wire provides coronary transstenotic pressure and is available in calculating myocardial fractional flow reserve(FFRmyo). FFRmyo is an important parameter to assess the coronary functional stenosis that is culprit for myocardial ischemia. It is calculated from the ratio of the mean transstenotic pressure to the mean pressure proximal to the stenosis during maximum coronary hyperemia. The value of FFRmyo considered as necessary for coronary intervention is below 0.75. Intravascular ultrasound(IVUS) is applied as both a diagnostic tool and for intervention purpose. It enabled tissue characterization of the vascular wall as well as measurements of vascular diameter, vascular lumen area and plaque area. It also aided in optimal devise selection, decision of interventional endpoint and assessment of restenosis. IVUS promoted deployment of high-pressure stents to obtain a large post-procedural lumen area as well as abolition of anticoagulation in case of optimal stent deployment. Coronary angioscopy has been developed to investigate the pathogenesis of acute coronary syndrome, where disrupted yellow plaque and overlying thrombus play important roles. Angioscopy has also evidenced regression of intimal hyperplasia after coronary stenting.

Magnetic resonance angiography for detection of occlusive neck and proximal vascular diseases

We reviewed magnetic resonance (MR) aortographies of the thoraco-cervical region of 422 patients. Two hundred sixty patients had ischemic cerebrovascular disease, 86 vertigo or dizziness, 22 syncope, 4 ischemic disease of the retina, 3 cervical bruit, and 47 had other intracranial diseases. MR aortography was performed on a 1.5 Tesla MRI using a special head-and-neck coil. Images were obtained using an overlapping multi-slab and three-dimensional time-of-flight technique. Of the 422 patients, 59 underwent conventional angiography, and the findings from their conventional arteriogram were compared with those of MR aortography. As a result, steno-occlusive lesions were found in the carotid system in 21.1% of the patients, in the vertebral system in 18.5%, and in the subclavian and innominate arteries in 2.1%. The diagnoses made based on the MR aortography were in accord with the diagnoses made with conventional arteriography in 49 patients (83.1%). In 8 patients (13.6%), however, the diagnosis based on the MR aortography was found to be overestimated compared with the definitive diagnosis with conventional angiography. In only 2 patients (3.3%), the MR aortography diagnosis was insufficient. Especially, subclavian steal was not diagnosed with the MR aortography, whereas the findings from the MR aortography helped to lead to the diagnosis of this abnormality. In conclusion, we found that MR aortography is a useful tool as a screening test for patients with occlusive extracranial cerebrovascular disease.

[Cervical epidural hematoma caused by cervical twisting after epidural anesthesia: a case report]

A case of cervical epidural hematoma caused by cervical twisting after epidural anesthesia was reported. A 41-year-old man who had had anterior fusion of C5 - 7 using a plate due to cervical spondylosis fifteen months before admission, had undergone epidural anesthesia through the C7/T1 interspace without difficulty for shoulder pain in a pain clinic. Two hours after injection, he complained of severe pain in his neck and both shoulders just after cervical twisting as was his custom. Within minutes he noted paresis of his left extremities. Neurological examination on admission revealed left side dominant tetraparesis and loss of pain and temperature sensations below the level of T4 on his right side. Laboratory data analysis and coagulation tests were normal. CT scans and MRI demonstrated an epidural hematoma with a small amount of air extending from C3 to the upper margin of C7. Four hours after the onset, a laminoplasty was performed from C3 to C7 with total removal of the hematoma. No bleeding site or any vascular abnormality was found to account for the hematoma formation. He was discharged with good recovery after operation. Most of the reported epidural hematomas associated with epidural anesthesia were related to coagulopathy, anticoagulant therapy or difficult puncture. On review of the literature, this is the first case of spinal epidural hematoma cause by cervical twisting after spinal anesthesia and which was without impaired coagulation or difficult spinal puncture. Cervical epidural hematoma should be considered as a possible complication in patients with pain or neurological deficits after some cervical manipulations.

Ocular tilt reaction with vertical eye movement palsy caused by localized unilateral midbrain lesion

A 60-year-old man developed diplopia and experienced difficulty moving his eyes. Vertical movement of each eye, including vestibulo-ocular reflex and smooth pursuit, was extremely limited. Horizontal eye movements were normal. His head position was tilted toward his left. There was 10 prism diopters of exotropia and 10 prism diopters of right hypertropia. Fundus photographs revealed a clockwise torsion of both eyes. These signs indicate leftward ocular tilt reaction. Magnetic resonance imaging showed a small area of an increased signal intensity localized in the midbrain dorsomedial to the red nucleus on the right side. Based on recent experimental evidence, it may be assumed that the unilateral lesion involving the right interstitial nucleus of Cajal most probably caused leftward ocular tilt reaction in our patient.

Phosphorus-31 magnetic resonance spectroscopy studies of pig spinal cord injury. Myelin changes, intracellular pH, and bioenergetics

RATIONALE AND OBJECTIVES

Phosphorus-31 (31P) nuclear magnetic resonance (NMR) spectroscopy was used to monitor changes in phosphocreatine (PCr), adenosine triphosphate (ATP), inorganic phosphate (Pi), intracellular pH (pHi), and free magnesium in the in vivo pig spinal cord after injury.

METHODS

Phosphorus-31 NMR spectra were acquired from healthy (n = 4) and injured pig spinal cords (n = 8) under in vivo conditions using a 4.7-tesla spectrometer. Spinal cords were injured by dropping a 20-g weight from 20 cm onto the surgically exposed cord surface.

RESULTS

In vivo spectra of injured cords revealed a reduction in ATP, PCr, pHi, and an increase in Pi. In addition, a broad resonance that is likely to arise from myelin phospholipids was reduced significantly after injury.

CONCLUSIONS

Phosphorus-31 NMR can be used to follow in vivo changes in high energy phosphates after injury and may have the potential to follow changes in myelin structure. This technique may prove important in the study of myelin breakdown after secondary, nonreversible spinal cord injury. Changes in high energy phosphates and pHi did not seem to parallel these putative changes in myelin structure.

Surgical treatment supposed natural history of the tethered cord with occult spinal dysraphism

We retrospectively evaluated the pre- and postoperative course of 34 tethered cord patients with occult spinal dysraphism in an attempt to infer the natural history of this disorder and to determine the effectiveness of the surgical treatment. There were 32 cases with lumbosacral lipoma and 2 with tight filum terminale. The age at surgery ranged from 1 month to 47 years old. Eight patients, aged 1 month to 4 years old, were asymptomatic; 26 had neurogenic bladder (26 cases) or motor problems affecting the legs (8 cases). None of the patients older than 5 years of age were asymptomatic. Untethering of the spinal cord was performed in all cases. The postoperative follow-up period ranged from 5 months to 11 years. During these periods, 7 (88%) of the 8 asymptomatic patients remained neurologically intact, 6 (23%) of the 26 symptomatic patients showed improved symptoms, and 15 patients (58%) remained unchanged. These results indicate that the neurological symptoms will appear progressively in the tethered cord patients, and that prophylactic surgery should be considered as early as possible.

Surgical treatment of syringomyelia associated with spinal dysraphism

Clinical and radiological features of syringomyelia in 15 patients with spinal dysraphism are reported. There were 8 patients with occult spinal dysraphism (lumbosacral lipoma) and 7 with spina bifida aperta (meningomyelocele). Syringomyelia with spinal dysraphism can be radiologically divided into two types according to the dysraphic state. The syrinx in the patients with occult spinal dysraphism occurred immediately rostral to the lipoma and was localized to the lower thoracic to lumbar levels, while in the meningomyelocele patients the syrinx extended from the cervical to the thoracic level. Large syrinx formation was recognized in 1 of the 7 occult spinal dysraphism cases and 3 of the 8 meningomyelocele cases. For syringomyelia with occult spinal dysraphism, 4 patients underwent syringo-subarachnoid shunting (S-S shunt, 2 cases) or syringostomy (2 cases) during an untethering operation. In the case of meningomyelocele, S-S shunts were placed in 2 patients. Collapse of the syrinx was achieved in all 6 patients who underwent S-S shunting or syringostomy. Decreased size of the syrinx was also noted in 3 occult spinal dysraphism patients who underwent untethering operations alone. In conclusion, a large syrinx in the case of spinal dysraphism should be surgically treated. S-S shunting is effective in both types of syringomyelia. Foramen magnum decompression may be an alternative method of surgical treatment for syringomyelia in patients with meningomyelocele.

Phosphorus-31 nuclear magnetic resonance spectroscopy of the spinal cord in the pig, rat, and rabbit

RATIONALE AND OBJECTIVES

To ensure that contamination-free phosphorus-31 nuclear magnetic resonance (31P-NMR) spectra of the spinal cord could be obtained, a porcine model was adopted that provided a large cord sample and a greater area free from adjacent muscle tissue.

METHODS

Phosphorus-31 NMR spectra were acquired from the porcine spinal cord under in vivo conditions using a 4.7-T spectrometer. Spectra also were collected from perchloric acid and lipid extracts, and excised freeze trapped samples of the rat, rabbit, and pig spinal cord.

RESULTS

The in vivo spectrum showed resonances corresponding to adenosine triphosphate, phosphocreatine, inorganic phosphate, phosphomonoesterase, and phosphodiesterase as confirmed by extracts. In addition, a broad resonance was observed that was assigned to myelin phospholipids.

CONCLUSION

Phosphorus-31 NMR spectra of the spinal cord revealed resonances common to brain tissue. Importantly, the existence of a previously undetected resonance, which is likely to correspond to myelin phospholipids, also is reported. This resonance may prove important in future studies monitoring changes in myelin in response to trauma and ischemia.

[Atlantoaxial dislocation with ventilatory insufficiency--report of two cases]

We performed electromyography and polysomnography in two cases of atlantoaxial dislocation with ventilatory insufficiency to determine the patients' respiratory patterns. The results showed that hypertrophic sternocleidomastoid muscles (SCMs) played an important part in their respiration. The diaphragm and intercostal muscles did not display marked electromyographic (EMG) activity, but the SCMs showed a great deal of phasic inspiratory activity during the daytime that decreased or disappeared during sleep. A 6-year-old boy with atlantoaxial dislocation related to spinal abnormalities was chiefly dependent on the SCMs for respiration and required mechanical ventilation when a sleep because the SCMs were completely inactive. A 4-year-old girl with atlantoaxial dislocation as the result of an automobile accident was partially dependent on the SCMs. She had no trouble breathing during the daytime, but polysomnography recordings showed recurrent hypopnea and desaturation during the night synchronous with decreased EMG activity of the SCMs. She also required mechanical ventilation to improve her long-term prognosis. Polysomnography should be performed in severe cases of atlantoaxial dislocation with respiratory failure in addition to routine respiratory function tests.

Use of the Morris water maze and acoustic startle chamber to evaluate neurologic injury after asphyxial arrest in rats

The study was performed to assess the utility of the Morris water maze (MWM) and acoustic startle reflex (ASR) for evaluating neurologic outcome in a rat model of asphyxial cardiac arrest. Rats were anesthetized, intubated, and chemically paralyzed. Control animals were decannulated and, after awakening, were extubated and returned to their housing. Experimental animals were asphyxiated by disconnecting the ventilator. Approximately 3.5 min after the disconnection, there was no measurable pulse. After 7 min of asphyxia, they were then resuscitated with resumed ventilation, chest compressions, epinephrine, and sodium bicarbonate. All animals were assigned to either MWM or ASR testing. The MWM is a 6-ft diameter tank filled with opaque water. In a fixed location of the tank, a 4-inch diameter escape platform is submerged just below the surface. MWM animals were tested on post-injury d 16-21 by recording the path and time taken to escape from three randomly assigned locations per d. ASR animals had s.c. leads placed over the right triceps and tibialis anterior muscles. The latency and rectified amplitude of the ASR was measured by recording the electromyographic impulse generated when the animal was startled by an acoustic stimulus. Animals were tested on post-injury d 6 and 7. After the last test session for each group, the animals' brains were removed for histopathologic examination. Asphyxiated MWM animals took longer to find the platform, and their paths were less direct than control animals (analysis of variance p < 0.05). The ASR of asphyxiated ASR animals had greater amplitude and shorter latency compared with controls (analysis of variance p < 0.05). Histologic examination revealed no abnormalities in control animals, but 80% of asphyxiated brains showed hippocampal neuronal injury and/or reactive gliosis in the CA1 segment. Abnormalities were more commonly detected in animals killed 7 d post-injury (ASR protocol) compared with animals killed 21 d post-injury (MWM protocol). We conclude that the MWM and ASR are useful for detecting neuronal injury in asphyxiated rats.

Spinal cord evoked potential monitoring after spinal cord stimulation during surgery of spinal cord tumors

Spinal cord evoked potentials (SCEPs) after spinal cord stimulation were used as a method of spinal cord monitoring during surgery of 6 extramedullary and 14 intramedullary spinal cord tumors. SCEPs were recorded from an epidural electrode placed rostral to the level of the tumor. Electrical stimulation was applied on the dorsal spinal cord from a caudally placed epidural electrode. The wave forms of SCEPs consisted of a sharp negative peak (N1) in 15 cases and two negative peaks (N1 and N2) in 5 cases. The N2 wave was markedly attenuated by posterior midline myelotomy, whereas the N1 activity showed less-remarkable changes by myelotomy. An increase in N1 amplitude was observed after the removal of the tumor in four extramedullary and three intramedullary cases. Of six patients that showed decreased N1 amplitude after the removal of the tumor, five patients developed postoperative motor deficits. However, there were four false-negative cases and one false-positive case in regard to changes of N1 amplitude and postoperative motor deficits. Four false results occurred in intramedullary cases. In two of them, postoperative symptoms indicated intraoperative unilateral damage to the spinal cord. The position of the stimulating electrode, the difference in thresholds of the axons for electrical stimulation between the right and left side of the spinal cord, or the change of the distance between the electrode and the spinal cord surface may account for these false results. Thus, our analysis of the changes of SCEP wave forms and early postoperative symptoms indicates that the sensitivity of this monitoring method to detect intraoperative insults to the spinal cord is unsatisfactory in spite of the reproducible wave forms. We conclude that SCEP monitoring can be used as an alternative method or in combination with other types of evoked potentials in patients with severe spinal cord lesions who show abnormal somatosensory evoked potentials preoperatively.

[Clinical application of phase contrast angiography]

"Phase Contrast Angiography" is a new technique of Magnetic Resonance Angiography as reported by Dumoulin CL et al. Using this technique, we can obtain images of vessels (angiograms) without injection of contrast medium. We present the results of phase contrast angiography on cerebral and spinal vascular disease. We utilized the General Electric SIGNA, 1.5 tesla NMR. One hundred and ninety-one cases of cerebral and spinal vascular diseases were scanned using phase contrast angiography. Included were 90 cases of occlusive vascular disease, 16 cases of moyamoya disease, 39 cases of arteriovenous malformation, and 28 aneurysms. The phase contrast angiography uses flow encoding gradient pulses, which impart a velocity-dependent phase shift to the transverse magnetization of moving spins. The resulting image contains only information from the moving spins; while information from stationary tissue remains suppressed. In cases using 3-D angiogram, we made 32 images 6 degrees apart in their projection direction and displayed them on a video terminal. We were able to visualize occlusions of vessels, aneurysms, bypassed vessels, and abnormal vessels of arteriovenous malformations. Retrospective evaluation comparing phase contrast angiography with conventional angiography of the stenotic findings on the horizontal portion of middle cerebral arteries (64 vessels of 32 patients), resulted in a false positive ratio of 39.1%. We obtained clinically valuable results regarding the hydrodynamics of patients using "phase contrast angiography" non-invasively. These results reveal not only "anatomical" images of vessels, but also "functional" images, which are sensitive to the pattern of the blood flow. This study would strongly suggest that phase contrast angiography presents a valuable tool for the clinical diagnosis of cerebral and spinal vascular diseases.

[Anterior approach for cervical dumb-bell typed neurinomas]

We experienced three cases of the dumb-bell typed cervical neurinoma. All of them compressed the spinal cord in the spinal canal, and had developed through the intervertebral foramen and compressed and displaced the vertebral artery. The decompression of the vertebral artery and reconstruction of the spine as well as the removal of the tumor were thought to be important. We used the anterior approach and were able to operate safely and completely. The anterior approach was thought to be effective for the surgical treatment of dumb-bell typed cervical neurinoma.

Scoliosis associated with syringomyelia presenting in children

The clinical presentations and radiological features of scoliosis accompanying syringomyelia were analyzed in 14 cases of syringomyelia associated with a in 14 cases of syringomyelia associated with a Chiari malformation in children. Scoliosis was the initial symptom in 11 out of 16 patients (64%) with syringomyelia and present in 14 (88%) at the initial examination. The scoliosis associated with syringomyelia was characterized by a higher incidence of a single curve (6 cases, 43%) and convexity to the left (7 cases, 50%) than seen in idiopathic scoliosis. The syrinx was shifted to the convex side of scoliosis on the axial section at the middle or lower thoracic level in patients with a single curve, and at the cervical or upper thoracic level in patients with a double curve. The authors think that the scoliosis develops in children as a result of damage done to the anterior horn, which innervates the muscles of the trunk, by an asymmetrically expanded syrinx.

Sacral nerve root cysts manifesting as localized unilateral perineal pain--case report

A 62-year-old female presented with multiple sacral nerve root cysts manifesting as localized unilateral perineal pain. Myelography just after contrast material injection revealed multiple cysts at the sacral level. However, perioperative dye injection showed hardly any flow in the reverse direction. Only the S3 nerve was constricted by hyperplasia of the dura mater, and adhered to the cyst wall. Other nerves were not constricted, nor adhered to cyst walls. The S3 nerve constriction and tight adhesion was the cause of the pain. The one-way flow of spinal fluid from the spinal subarachnoid space to the cysts is probably closely correlated with cyst formation.

[Spinal epidural stimulation for central pain caused by spinal cord lesion]

Epidural spinal cord stimulation was carried out in 4 patients with denervation caused by spinal cord lesion, and we reviewed previously reported cases. Initial result showed at 1 week in 100% of our cases, but about 1/3 of the cases, even those with the same denervation caused by spinal cord lesion, had no pain relief at this stage in previously reported cases. In our cases, excellent pain relief was gained temporarily, even though the painful area and the spinal cord lesion were separated somatotopically in 2 cases (case 3, 4). Temporary success bore no relationship to quality and duration of pain. In all cases except case 1, a rapidly decreasing effectiveness was noted, and finally no pain relief was gained at all after 4, 3 and 5 months, respectively. In case 1 there was persistent pain relief estimated at 70-80% after 19 months, only when the spinal cord was stimulated. Epidural stimulation also produced sensations in the painful area. Spinal cord stimulation would suppress at least the dorsal horn neurons which were destroyed by various kinds of diseases. A decline in effectiveness with time would occur due to essential causes of the deafferentation pain, such as anatomical and regeneration factors.

[Quantitative analysis of cerebrospinal fluid dynamics in syringomyelia using cine MRI with pre-saturation]

Some reports show the qualitative analysis of cerebrospinal fluid (CSF) pulsation in the subarachnoid space and the syrinx using cine magnetic resonance imaging (MRI). However, few reports studied the quantitative analysis of CSF pulsation. We report here the results of quantitative analysis of CSF pulsation using the cine MRI with pre-saturation pulse. Using flow phantom, we calibrated the correlation between the true velocity and calculated velocity acquired from the movement of pre-saturated low signal. Three cases of syringomyelia with Chiari malformation, two cases of traumatic syringomyelia, and three normal volunteers were examined using this technique, and we could obtain time-velocity curves of CSF in both subarachnoid spaces and syrinx. Although obvious pulsation of CSF was observed in the syrinx of all Chiari malformations, no pulsation of CSF was observed in the syrinx of traumatic syringomyelia. CSF in the syrinx moves upward in the early systolic cardiac cycle, downward in the systolic cycle, and upward again in the diastolic cycle. Patterns of CSF pulsation in syrinx were similar to those in the subarachnoid space, but "phase" of these pulsations differed from case to case. These results suggest the close relationship between CSF pulsation in the syrinx and CSF obstruction at the cranio-vertebral junction. Dissociation of the "phase" of CSF pulsation in the syrinx and subarachnoid space may be significant in the analysis of the pathogenesis of syringomyelia.

[Post-traumatic syringomyelia. Report of three cases]

Three cases of post-traumatic syringomyelia are presented and the mechanism of syrinx formation is discussed. Two cases were examined radiologically. Computed tomography and magnetic resonance images (MRI) showed an expansive syrinx with adhesive arachnoiditis in the thoracic levels below the injury site and a localized syrinx on the posterolateral gray matter in the cervical levels above the injury site. These syrinxes existed below the C2 level and had no communication with the fourth ventricle. The other was an autopsy case. Postmortem examination revealed that a syrinx existed from C2 to Th6 and had no communication with the fourth ventricle or the central canal. It is concluded that small traumatic cavities in the gray matter evolve to an extensive syrinx by cerebrospinal fluid (CSF) entering via the posterior root entry zone, and adhesive arachnoiditis is an important factor in increasing the CSF which is entering. MRI was useful for the diagnosis.

[Usefulness of MRI in the diagnosis of spontaneous hematomyelia; a case of intramedullary cavernous hemangioma]

Recent improvement of MRI has enabled us to clearly visualize intramedullary spinal lesions which previously could not be recognized by CT scan or myelography. We reported a case of hematomyelia caused by intramedullary cavernous hemangioma. In this case, MRI was very useful in efforts to recognize the lesions. With the use of MRI, we will be able to accurately ascertain the location and characteristics of intramedullary spinal lesions. The number of surgically treated cases of idiopathic hematomyelia will increase in the future.

[Histological investigation on hydroxyapatite ceramics as materials of artificial bone grafts in the cervical spine]

The purpose of this study is to understand the utility of the hydroxyapatite (HA) ceramics as artificial bone graft substances in the cervical spine.

METHOD

Dense and porous HA were implanted into the vertebral body and intervertebral space of the adult dog cervical spine and the implanted cervical bones were removed 4, 8 and 24 weeks after implantation and examined by contact microradiography (CMR), and histological observations of the non-decalcified material stained with Van Gieson's and decalcified material stained with hematoxylin and eosin.

RESULTS AND CONCLUSION

1. Sufficient formation of new bone with the bone marrow was recognized on the surface and in the pores of the porous HA being implanted to the cervical vertebra. 2. Dense HA was inadequate for the implantation into cervical areas because of its physical nature, such as glass-like smooth surface and the extreme hardness. 3. HA was not fit for usage in the intervertebral space of the cervical spine because of its total ineffectiveness in the functions such as the supporting heavy weight of the head and the mobility and its histologically poor activity of the new bone formation in the intervertebral space.

Spinal cord herniation associated with an intradural spinal arachnoid cyst diagnosed by magnetic resonance imaging

Two rare cases of spinal cord herniation associated with intradural spinal arachnoid cyst are reported. A preoperative magnetic resonance imaging scan demonstrated the presence of spinal cord herniation, identified as a protrusion continuous with the spinal cord. Surgery upon the intradural spinal arachnoid cyst improved progressive neurological dysfunction. The authors postulate that spinal cord herniation occurred for the following reason: The pressure of the intradural arachnoid cyst on the dorsal aspect of the spinal cord caused thinning of the dura, leading to a tear and, thus, the development of an extradural arachnoid cyst. Along with the enlargement of intradural arachnoid cyst, the spinal cord herniated through the tear in the dura into the extradural arachnoid cyst.

[A case report: intraspinal canal osteochondroma at the cervicothoracic junction causing spinal cord compression]

Osteochondromas are one of the most common benign tumors. They typically develop on long, tubular bones, only rarely compressing the spinal cord. We report the case of a 9-year-old boy who suffered paraparesis secondary to a cervical osteochondroma based at the vertebral body. The tumor was removed using laminectomy. CT scanning, plain X-ray films, and MR imaging were used in the preoperative assessment of the lesion and the operative method.

[Stab wounds of the spinal cord by a kitchen knife: report of a case]

A case of spinal cord injury due to stab wounds by a kitchen knife is presented. A 41-year-old male was hospitalized because of spinal cord injury resulting from stab wounds inflicted with a kitchen knife in the posterior cervical area. Neurological examination on admission showed paraplegia, disappearance of deep tendon reflex in both lower extremities, sensory disturbance below T1 level, left Horner's syndrome and urinary disturbance. In addition to these symptoms cerebrospinal fluid was leaking from the wounds. An emergency operation was performed. After laminectomy of C7 and T1, we found that the spinal cord was almost completely split at C7/T1 level. Dural plasty was performed. Neurologically, sensory disturbance was slightly improved at 4 months after the injury. Initial MRI (TR: 200 msec, TE: 20 msec) revealed high intensity at C7/T1 level which was damaged by the kitchen knife. MRI 5 months after the injury revealed low intensity on T1 weighted imaged, high intensity on T2 and proton weighted image. The occurrence of the spinal cord injury due to stab wounds by a kitchen knife is very rare in Japan. MRI is useful in the diagnosis of stab wounds of the spinal cord.

[A case of epidural lipomatosis presenting spinal ataxia]

A 41-year-old man was doing well until July 1989, when he noted numbness over soles, followed 4 months later by difficulty in walking. These symptoms were progressively getting worse, and he was admitted to our department on June 12, 1990. General physical examination was unremarkable. Neurologically cranial nerves were intact except old right, traumatic strabismus. Muscle tone and deep tendon reflexes were normal throughout, but bilateral Babinski and Chaddock reflexes were present. Mild weakness of lower extremities were found on muscle testing (4/5). In sensory system, superficial sensory disturbance below T10 was seen, and markedly diminished vibration and position senses of lower extremities were noted. Cerebellar test was intact, although unsteadiness was found on heel-shin test. Romberg sign was definitely positive. His gait was wide-based and ataxic. Laboratory data showed no abnormalities in CBC, chemistry, urinalysis, serological tests and endocrinological examinations. Spinal MRI (Siemens 1.5 Tesla) showed abnormal deposition of epidural fatty tissues compressing spinal cord with flattening of cord from T4 to T8. Spinal ataxia as compressive myelopathy due to epidural lipomatosis was considered and he underwent laminectomy from T4 to T8 with improvement in walking. Epidural lipomatosis is an unusual cause of spinal cord compression, presenting compressive myelopathy, radiculopathy, cauda equina syndrome, intermittent claudication, or back pain. Most of cases were associated with long-term administration of adrenocortical steroid hormone, or underlying diseases, except only 3 cases including ours. This is the first case of spinal epidural lipomatosis presenting progressive gait disturbance due to spinal ataxia.

[Diagnosis and surgical treatment of spinal hemangioblastoma]

Spinal hemangioblastoma is a rare tumor. Its incidence varies from 1.6 to 2.1% of primary spinal cord tumors. In this report, the authors described MRI (magnetic resonance imaging) of spinal hemangioblastoma and its surgical results. [MATERIALS AND METHODS] This series included 10 spinal hemangioblastomas studied with CT or MRI. There were 8 men and 2 women. The age ranged from 21 to 68 years, with a mean age of 45 years. 6 patients were preoperatively and postoperatively studied with a resistive 0.15 T system (Toshiba MRT 15A) or a superconductive 1.5 T system (GE Signa or Siemens Magnetom). The lesions were single in 8 out of 10 patients and multiple in 2. 10 spinal hemangioblastomas were located in intramedullary space and 2 in both intramedullary and extramedullary space. 8 out of 10 patients (80%) were associated with cyst. [RESULTS] (1) MRI In T1-weighted MR images after administration of Gd-DTPA, the solid component of the tumor enhanced brilliantly. The enhanced lesions contained serpiginous areas of signal void, reflecting vascular structures in 5 out of 6 cases. The intrinsic spinal cord signal was heterogenous with low intensity areas representing the associated cyst. The cyst appeared either isointensive to cerebrospinal fluid (CSF) or hyperintense relative to CSF and slightly hypointense relative to the spinal cord. The precise delineation of the tumor was impossible without enhancement. Noncontrast T1-weighted MR images displayed diffuse widening of the spinal cord. On T2-weighted MR images, all regions of the spinal cord enlargement increased in signal. (2) Postoperative results All 10 cases of spinal hemangioblastomas were totally removed with good postoperative results and the associated cysts were drained. The postoperative MRI showed the disappearance of the tumor and significant reduction in the size of the cyst. [CONCLUSION] (1) Gd-DTPA enhanced MRI was useful in defining and outlining the solid component of spinal hemangioblastoma. (2) The complete removal of the tumor with only drainage of the cyst was possible with good postoperative results.

[Magnetic resonance imaging of posttraumatic syringomyelia and its surgical treatment]

Posttraumatic syringomyelia is an uncommon but significant late complication of spinal cord injury. It occurs in approximately 1.1 - 3.2% of cases of spinal injuries. With the increasing availability of CT and magnetic resonance imaging (MRI), the incidence of posttraumatic syringomyelia is increasing. The purpose of this report is to show MRI of posttraumatic syringomyelia and to assess the results of surgical treatment. Materials and Methods This series included 16 cases of posttraumatic syringomyelia studied with MRI. 9 out of 16 cases showed delayed deterioration of neurological symptoms following spinal injuries. The interval between the trauma and the delayed symptoms of deterioration was from 2 years 2 months to 32 years (mean, 8 years and 5 months). There were 13 men and 3 women. The age ranged from 22 to 69 years, with a mean age of 42 years. The initial spinal cord injury was located in the lower cervical region in 4 cases, the thoracic region in 8, and the upper lumbar region in 4. All the patients were studied with resistive 0.15T system (Toshiba MRT 15 A) or a superconductive 0.5T system (Toshiba MRT 50 A) or a superconductive 1.5T system (GE Sigma or Siemens Magnetom). Six patients underwent 8 operative procedures for posttraumatic syringomyelia. Syringoperitoneal shunt was performed in 4 patients, syringosubarachnoid shunt in 3 and ventriculoperitoneal shunt in one. Results 1. MRI In all cases, the posttraumatic syringomyelia was easily diagnosed by MRI. The syrinx extended superiorly and/or inferiorly from the area of the old trauma. In 4 out of 16 cases, the syrinx extended into the medulla oblongata.(ABSTRACT TRUNCATED AT 250 WORDS)

[Metastatic Grawitz's tumor to the cauda equina: case report]

A case of Grawitz's tumor metastasizing to the cauda equina is presented. A 51-year-old male was hospitalized due to severe low back pain radiating to the left lower extremity. Neurological examination showed only hyporeflexia of the left patella reflex and positive Lasegue's sign. MRI showed intradural mass at the L4 level. Preoperatively, we diagnosed a cauda equina tumor. A laminectomy of both L3 and L4 was performed, and total removal of the cauda equina tumor was performed. Microscopically, the tumor cells were large, the appearance of the cytoplasm ranging from optically clear with sharply outlined boundaries, to deeply granular, with many transitional forms. These histological findings were typical findings of Grawitz's tumor, and were the same as those of this patient's renal tumor. Finally, we diagnosed Grawitz's tumor metastasizing to the cauda equina. Metastatic cauda equina tumor from outside the central nervous system is very rare and only 7 cases have been reported. This case is the first one of Grawitz's tumor spreading to the cauda equina.

[Anterolateral approach to giant cell tumor in T4 vertebral body]

A case of giant cell tumor involving the Th4 vertebral body is reported. A 27-year-old man, who had a 2 month history of back pain and paraparesis, was admitted to our department in August, 1986. On the first admission, he manifested severe paraparesis and sensory disturbance below the Th5 dermatome level. Neuroradiological examination demonstrated an epidural tumor involving the Th4 vertebral body and compressing the spinal cord. Emergency laminectomy for decompression and biopsy was performed. The surgical specimen was a giant-cell tumor. 6 weeks after the first operation, total removal of the tumor and anterior fusion of the Th 3-5 with iliac bone graft was performed through the anterolateral transthoracic approach. Postoperative course was uneventful. A curative resection and immediate stabilization was thus able to be undertaken through the anterolateral transthoracic approach, when the epidural tumor was confined to the thoracic vertebral body.

Syringo-subarachnoid shunt for syringomyelia associated with Chiari malformation (type 1)

The authors report the surgical results of 28 patients with syringomyelia associated with Chiari malformation (type 1). 28 patients underwent 34 operative procedures. Syringo-subarachnoid shunt was performed in 28 patients, foramen magnum decompression with syringo-subarachnoid shunt in three, ventriculo-peritoneal shunt in one, terminal syringostomy in one, and foramen magnum decompression with terminal syringostomy in one. In an average postoperative follow-up period of 3 years and 9 months ranging from one year to 7 years and one month, neurological symptoms and signs improved in 24 out of 28 patients (82%). Some improvement was noted in sensory deficit and motor weakness. In 3 patients, the symptoms did not change. In 3 patients whose symptoms were unchanged, preoperative studies demonstrated atrophy of the spinal cord, in which irreversible changes were shown. The symptoms deteriorated in one patient. In one patient whose symptoms increased 3 months after syringo-subarachnoid shunt, shunt insufficiency due to postoperative adhesive arachnoiditis was responsible for neurological deterioration. The authors propose that syringo-subarachnoid shunt is effective as a surgical procedure for syringomyelia associated with Chiari malformation (type 1) if the patient does not have symptoms due to Chiari malformation or has only mild signs and symptoms which do not require foramen magnum decompression, such as nystagmus or atrophy of sternocleidomastoid muscle.

A case of systemic lupus erythematosus--its clinical and MRI resemblance to multiple sclerosis

We documented a case of systemic lupus erythematosus with clinical features of multiple sclerosis who developed transverse myelopathy. Magnetic resonance imaging showed the presence of an abnormal high signal intensity in the gray matter of a swollen spinal cord corresponding to the patient's neurological deficits. After two previous episodes of exacerbation and remission consistent with the clinical diagnosis of multiple sclerosis, right hemiparesis and hemisensory disturbances ensued, then lupus nephritis was confirmed by a renal biopsy.

Infiltrating spinal angiolipoma causing myelopathy: case report

We present a case of an infiltrating spinal angiolipoma demonstrating extension into the vertebral body and the spinal epidural space. The infiltration into the epidural space caused myelopathy. About 40 cases of spinal angiolipoma and angiomyolipoma have been reported; however, only a few cases have been the infiltrating type. The radiological findings were similar to those of vertebral hemangioma, but poor enhancement of the angiolipoma on contrast-enhanced computed tomographic scans differentiated between them. The infiltrating epidural tumor was removed, and the clinical symptoms improved remarkably. Total removal of the tumor and stabilization of the involved vertebral body using the anterolateral approach may be desirable when a diagnosis of angiolipoma or angiomyolipoma is confirmed preoperatively.

[A case of intramedullary spinal cord metastasis from adenocarcinoma of corpus uteri]

The authors present a case of a woman with intramedullary spinal cord metastasis from adenocarcinoma of the corpus uteri. Such a case was not able to be found in the literature. A 54 year-old woman complained of right upper extremity weakness and headache. CT scan showed abnormality, and removal of a brain tumor was performed. After that, total hysterectomy, retroperitoneal lymphadenectomy and chemotherapy was carried out. Three months later, she suddenly experienced bilateral weakness in her lower extremities. After a few days she was unable to walk. Gd-DTPA enhanced MRI showed an abnormal mass at the upper part of the conus medullaris. Total removal of the intramedullary tumor was performed and adenocarcinoma was diagnosed histopathologically.

Hydrosyringomyelia associated with a Chiari I malformation in children and adolescents

The clinical presentation, radiological features, and results of surgical treatment were analyzed in 17 cases of hydrosyringomyelia associated with a Chiari malformation, in children and adolescents younger than 20 years of age. The initial symptoms were a skeletal abnormality (71%), such as scoliosis (11 patients) or pes cavus (1 patient), pain or numbness (24%), and motor weakness (6%). Frequently seen signs on admission were sensory deficit (100%), scoliosis (85%), muscle weakness (64%), muscle atrophy (35%), and lower cranial nerve palsy (35%). The characteristic neurological findings were unilateral sensory and motor deficits (65%) with decreased or absent deep tendon reflexes on the same side. The localization of the syrinx on the axial section varied according to the level, even in the same patient. In 11 patients with unilateral sensory disturbances or unilateral sensory and motor deficits, the syrinx was located in the region corresponding to the posterolateral portion on the same side as that of sensory disturbance at the cervical or thoracic level. On the other hand, in 6 patients with bilateral sensory and motor deficits, the syrinx was located in the central portion and extended into the posterolateral portion of the more affected side. A syringosubarachnoid shunt was placed in 16 patients, foramen magnum decompression without closure of the obex was performed in 1 patient, ventriculoperitoneal shunt in 1 patient, terminal syringostomy in 1 patient, and foramen magnum decompression with terminal syringostomy in 1 patient. In 15 of 17 patients (88%), the neurological symptoms improved after an average follow-up of 4 years and 1 month. We think that as a surgical treatment, placement of a syringosubarachnoid shunt is effective.

Biosynthetic pathways of pteridines and their association with phenotypic expression in vitro in normal and neoplastic pigment cells from goldfish

The distribution of GTP-cyclohydrolase I, pyruvoyl tetrahydropterin (dysopropterin) synthase, and pyruvoyl tetrahydropterin reductase in goldfish erythrophores, melanophores, and erythrophoroma cells in vitro has been revealed by specific biochemical assays. The activity of pyruvoyl tetrahydropterin synthase in the erythrophores is nearly the same as that in rat kidney and pineal gland. Results of the simultaneous quantification of unconjugated pteridines (biopterin, sepiapterin, neopterin, and pterin) by HPLC indicate that the total amounts of these derivatives present in these cells and in the respective culture media are closely correlated with the activities of these enzymes. These findings imply that these cells are capable of the autonomous synthesis of pteridines, which most likely proceeds from GTP to 6-lactoyl-5,6,7,8-tetrahydropterin (reduced sepiapterin), via dihydroneopterin triphosphate and pyruvoyl tetrahydropterin, through reactions catalyzed by these enzymes. A comparison of pteridine metabolism between clones of the stem cell type and the yellow-pigmented clones induced from erythrophoroma cells suggests that brightly colored pigmentation involves two separate phases: the biosynthesis of pteridines and their deposition in the pigment organelles. The presence of the highly active pteridine-synthesizing enzymes in melanophores and melanogenic erythrophoroma cells strongly suggests a loose commitment to the expression of pigment phenotypes in this species.

[Effect of mannitol administration and myelotomy on acute experimental spinal cord injury: investigation by spinal cord evoked potential]

The authors reported the changes in spinal cord evoked potential following impact injury by the weight-dropping technique in untreated and treated animals. The effect of mannitol and myelotomy therapy on spinal cord evoked potential in experimental spinal cord injury was discussed. (Materials and Methods) 32 adult dogs, ranging in weight from 9 to 13 kg, were used. 28 dogs received 300 gm-cm contusion of the T10 spinal cord. Eight dogs were not treated and twenty dogs were treated with mannitol. Ten dogs were treated with intravenous continuous infusion of mannitol (1g/kg/hr) 30 minutes after the injury, and ten dogs with intravenous bolus injection of mannitol (2 g/kg) at 30 minutes and 3 hours after the injury. At one hour after the injury, five dogs with 400 gm-cm contusion were treated with posterior midline myelotomy. The spinal cord evoked potential following direct stimulation of the spinal cord was recorded from the epidural space for 5 hours. The recording electrode was located cephalad to the site of the impact injury. (Results and Discussion) In each group, the amplitude of I potential decreased remarkably immediately after the injury. Subsequently, gradual recovery was obtained. In the untreated 300 gm-cm contusion group, no apparent improvement was seen from one hour after injury. On the other hand, in the mannitol-treated group, the recovery of the amplitude was superior to that found in the untreated group at a significant level of P less than 0.05. However, in the group with intravenous bolus injection of mannitol, the recovery was transient.(ABSTRACT TRUNCATED AT 250 WORDS)

[MR imaging of cervical disc disease: value GRASS imaging]

Since magnetic resonance imaging (MRI) technology has been greatly improved, MRI for cervical disc disease has become widely used in many facilities. Among non-invasive procedures, MRI is regarded as one of the most useful ones. Conventional myelography, CT myelography, and MRI were performed on 10 patients with cervical disc disease. The authors discussed the correlation between conventional myelography, CT myelography, and MRI as regards their ability to determine the localization and the laterality of disc protrusion and osteophyte. In our MRI study, we use both short-echo (SE) images and GRASS images. The parameters of our GRASS included 5mm-thick sections. TR = 200, TE = 20, and flip angles of 10 degrees. This pulse sequence generates images with high signal cerebrospinal fluid (CSF), resulting in a high-contrast CSF-spinal cord, osteophyte, and disc protrusion. As yet, although it easily shows the localization and laterality of the disc and/or osteophyte, image quality of the GRASS is not yet sufficient to allow us to evaluate detailed deformity of the spinal cord and nerve root. The authors stress the usefulness of this GRASS image for the evaluation of suspected cervical disc disease.

[Clinical and neuroradiological features of syringomyelia associated with Chiari malformation]

The clinical presentation and radiological features were analyzed in 30 cases of syringomyelia associated with Chiari malformation. None of the patients had spinal dysraphism. The age on admission ranged from 6 to 59 years with a mean of 27 years. Syringomyelia was diagnosed by CT myelography and or MRI from 1982 to 1988. The initial symptoms were skeletal abnormality (43%) such as scoliosis (12 cases) or pes cavus (one case), unilateral pain or numbness (40%) and unilateral motor weakness (17%). Frequently seen signs on admission were sensory deficit (100%), scoliosis (57%), muscle weakness (57%), muscle atrophy (37%) and lower cranial nerve palsy (40%). The neurological findings were asymmetrical in all patients. The characteristic neurological findings in the cases presenting under 20 years of age were unilateral sensory and motor deficits (61%) with decreased or absent deep tendon reflex on the same side. The localization of the syrinx in axial section varied according to the level even in the same case. In 15 cases with unilateral sensory disturbance or unilateral sensory and motor deficit, the syrinx was located in the region corresponding to the posterolateral portion on the same side as that of sensory disturbance in the cervical or thoracic level. On the other hand, in 15 cases with bilateral sensory and motor deficit, the syrinx was located in the central portion and extended into the posterolateral portion of the more affected side.(ABSTRACT TRUNCATED AT 250 WORDS)

Mobile schwannoma of the cauda equina diagnosed by magnetic resonance imaging

Three cases of a mobile cauda equina schwannoma, preoperatively diagnosed by magnetic resonance imaging, are described. When dealing with tumors of the cauda equina, it is important to carry out a second magnetic resonance imaging scan after changes in posture, bearing in mind the possibility of mobility of the tumor.