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The aim of lumbar disc herniation surgery is the removal of herniated disc material (HDM) and complete decompression of the nerve root. As some patients present with residual HDM, we examined the ability of intraoperative ultrasound (IOUS) to detect this material. Between February 2006 and June 2007, we used IOUS in 30 patients undergoing surgery for lumbar disc herniation. They were 17 men and 13 women; their ages ranged from 22 to 63 y (mean 44.0 y). The level surgically addressed was L3/4 in 1, L4/5 in 14 and L5/S1 in 15 patients; they were operated in the prone position. After placing a 3-4 cm midline skin incision, partial hemi-semilaminotomy was performed. HDM was removed through a bone window; a surgical microscope was used during the operation. After removal was judged as adequate, IOUS was performed; 17 patients also underwent IOUS before removal of the herniated disc. For the acquisition of IOUS images, we used LOGIQ 9 and 8c microconvex probes (GE Healthcare, Wauwatosa, WI, USA). The normal anatomical structures were well visualized. HDM was iso- to hyperechoic compared with normal nerve tissue. In three of 17 patients, the dural sac and nerve root could not be distinguished from HDM before removal, although in all 30, the decompressed dural sac, intradural cauda equina and nerve root were well visualized. We posit that the echogenicity of nerve tissue was raised due to compression, rendering it similar to that of the herniated disc. In two patients, IOUS detected residual disc material; the surgical procedure was resumed and sufficient removal was accomplished. IOUS monitoring is safe, convenient and inexpensive. It is also highly useful for the detection of residual HDM and the confirmation of adequate nerve root decompression.

The incidence of cervical spondylosis in the elderly is increasing with the higher proportion of elderly individuals among the Japanese population. The present study retrospectively analyzed the clinical and radiological features of this clinical entity in 107 patients with cervical spondylosis aged 70 years or older surgically treated between 1995 and 2005. The patients were divided into Group 1 (n = 60) aged between 70 and 74 years, and Group 2 (n = 47) 75 years or older. Patients with localized compression within 2 levels responsible for the neurological symptoms underwent anterior fusion, and patients with a narrow spinal canal were treated by laminoplasty. The pre- and postoperative neurological status (Neurosurgical Cervical Spine Scale) and postoperative complications were compared. More patients in Group 2 required laminoplasty but most patients underwent single-level anterior fusion. There was no statistically significant difference in the surgical results. Group 2 had a much higher ratio of anterior fusion at the C3-4 level. Many of the aged patients had multiple risk factors. Surgical decompression for cervical spondylosis is beneficial even in elderly patients. Single-level anterior fusion to treat the lesion most responsible for the symptoms is the least invasive choice. Elderly patients tend to present with multiple risk factors so require careful perioperative management.

A 33-year-old man presented with a rare case of lumbar epidural venous varix causing radiculopathy manifesting as sciatica exacerbated during bowel movements. The left straight-leg raising test was positive and patellar tendon reflex was lost. Lumbar magnetic resonance imaging showed a mass lesion in the epidural space at the L4 level just anterior to the dural sac on the left, appearing as hypointense on T1- and hyperintense on T2-weighted images, with ring-like enhancement with gadopentetate dimeglumine. He underwent surgery under a preoperative diagnosis of cystic nerve sheath tumor. After left hemilaminectomy, intraoperative ultrasonography showed a low echoic mass lesion ventral to the L4 nerve root. The mass was dark blue with a smooth wall. Tearing of the wall resulted in continuous bleeding. After removal of the lesion, we confirmed that the dura of the nerve root was intact. Histological examination of the surgical specimen confirmed venous tissue. The postoperative course was excellent. Lumbar epidural varix is difficult to diagnose preoperatively. Lumbar epidural varix should be considered if the lesion is smaller on preoperative than intraoperative imaging, or disap- pears with bleeding cessation, as this may avoid unnecessary widening of the operative field. The correct preoperative diagnosis remains difficult, so we recommend surgical removal and histological confirmation.

Background In spinal surgery, repair of the dura is difficult when it is torn or fragile or is ossified as in cases with ossification of posterior longitudinal ligament. We report our experience with a nonsuture dural repair technique in patients undergoing spinal surgery; it uses a dura substitute composed of polyglycolic acid (PGA) mesh and fibrin glue. Here, we report the efficacy and safety of nonsuture duroplasty using PGA mesh and fibrin glue (PGA-fibrin sheet). Methods The artificial dura mater is composed of a PGA-fibrin sheet. The dural defect is covered with a patch sprayed with fibrin glue without suturing to the dura mater. We first evaluated this technique in an experimental study by performing water leakage tests. Between May 2001 and January 2005, we used it in 160 spinal surgeries that required intraoperative dura repair. Results Our preliminary tests showed that the threshold for water pressure without leakage was 161 ± 42 and 96.5 ± 32 mm Hg when the unsprayed margin around the perimeter of the patch was 5 and 2 mm, respectively. Of the 160 operated patients, 10 (6.3%) experienced subcutaneous cerebrospinal fluid (CSF) leakage. Of these, 6 required a second operation; in the other 4, the CSF collection diminished spontaneously. There were no other complications such as allergic reaction, adhesion, or infection. Conclusion In combination with CSF diversion, the PGA-fibrin sheet is a viable alternative method for dural repair in spinal surgery.

A 62-year-old male presented with a rare case of ligamentum flavum hematoma manifesting as low back pain and gait difficulty beginning 1 month before consulting our institute. He had no history of lumbar spine surgery or lumbar puncture. However, he might have suffered forgotten back injury while practicing martial arts. Magnetic resonance imaging showed a heterogeneous intensity mass lesion with a cystic component at the L3-4 levels. The lesion was totally removed through a hemilaminectomy. Intraoperative and histological findings confirmed the diagnosis of old hematoma with granulomatous change in the ligamentum flavum. Postoperatively, his low back pain and gait difficulty resolved within a few days.

Objective Patients with ossification of the posterior longitudinal ligament (OPLL) sometimes present with acute spinal cord injury caused by only minor trauma. In the present study, we reviewed our experience of acute cervical cord injury associated with OPLL to understand the pathomechanisms and to provide clinical information for management of this disorder. Methods Twenty-eight patients were retrospectively analyzed. There were 26 men and 2 women, aged 45 to 78 years (mean, 63.0 yr). Most patients experienced incomplete spinal cord injury (Frankel Grade A, 3; B, 1; C, 15; and D, 9). Results Radiological studies revealed continuous- or mixed-type OPLL in 14 patients and segmental-type OPLL in 14 patients. The sagittal diameter of the spinal canal was reduced to 4.1 to 10 mm at the narrowest level as a result of OPLL. Developmental size of the spinal canal was significantly smaller in the group with segmental OPLL. Magnetic resonance imaging scans revealed that spinal cord injury occurred predominantly at the caudal edge of continuous-type OPLL or at the disc levels. Surgery was performed in 24 patients either by posterior (18 patients) or anterior (6 patients) decompression at various time intervals after the trauma. Twenty patients (71%) displayed improvement in Frankel grade. Conclusion The present study demonstrates the preexisting factors and pathomechanisms of acute spinal cord injury associated with cervical OPLL. Magnetic resonance imaging is useful to understand the level and mechanism of injury. Further investigation will be needed to elucidate the role of surgical decompression.

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.

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.

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.

Upper and lower lumbar disc herniation apparently have different background, symptoms, and operative results. This retrospective study reviewed the clinical records of 403 patients (409 discs) who underwent lumbar microdiscectomy performed by different surgeons at our institute between 1999 and 2009. The 290 male (72.0%) and 113 female (28.0%) patients were aged from 19 to 77 years (mean 44 years). Demographics, symptoms, and static and dynamic radiographic and magnetic resonance images obtained at the L1-2, L2-3, L3-4, L4-5, and L5-S1 intervertebral levels were analyzed. Of the 409 herniations, 3 were at L1-2, 9 at L2-3, 21 at L3-4, 166 at L4-5, and 210 at L5-S1. The mean age at herniation at L1-2 and L2-3 levels was 55.7 years. Patients with herniation of discs at L3-4 or above were significantly older than patients who suffered herniation at L4-5 or below (p < 0.0001), and the incidence of urinary disturbance was significantly higher in patients with herniation at L1-2 and L2-3 levels (p = 0.0013). The incidence of degenerative scoliosis was significantly higher in patients with herniation at L1-2 and L2-3 than in those with herniated discs at L3-4 or below (p < 0.0001). Patients with upper lumbar disc herniation were older and manifested a higher incidence of urinary disturbance. A high incidence of degenerative scoliosis was noted in the course of prolonged degenerative processes.

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.

OBJECTIVE AND IMPORTANCE: Bow hunter's stroke is a symptomatic vertebrobasilar insufficiency caused by stenosis or occlusion of the vertebral artery at the C1-C2 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.

This study is a retrospective analysis of 146 patients, 85 males and 61 females aged 21-80 years (mean 52 years), with cervical disk disease who underwent anterior fusion and titanium cage implantation with follow-up periods of no less than 72 months after surgery. All patients underwent the conventional anterior cervical approach. After removing the protruded disk and osteophyte, cylindrical titanium cages were placed. Single, two, and three level fusion was performed in 76 (52%), 64 (44%), and 6 (4%) patients, respectively. Functional assessment used the Neurosurgical Cervical Spine Scale (NCSS). The curvature index and range of motion were evaluated pre- and postoperatively. The clinical outcomes were satisfactory and there were no significant complications. The mean NCSS was 9.7 before and 12.7 at 1 year after the operation, and 12.1 at final examination. No postoperative cage extrusion or pseudoarthrosis occurred, but the cages descended in 10 patients (7%) although alignment was satisfactory. At 5 years after the operation, 140 of the 146 patients (96%) had solid fusion. The long-term results of anterior fusion with titanium cage implantation in patients with cervical disk disease were satisfactory. Titanium cage placement is a highly useful alternative to the conventional treatment method in these patients.

OBJECTIVE: Because surgery in elderly patients should be minimally invasive, interspinous process distraction has been widely used in this group to treat lumbar canal stenosis. We developed a new interspinous process distraction spacer composed of hydroxyapatite ceramic. In this work, we demonstrate the usefulness of this novel device. METHODS: Since 2003, we operated on 19 elderly patients with lumbar canal stenosis, including 14 men and five women. Their mean age was 70.1 years, We compared the intervertebral angle, posterior disc height, and interspinous process distance on midsagittal magnetic resonance images obtained before and after the surgery. We also assessed clinical outcomes by using the Visual Analog Scale and the Zurich Claudication Questionnaire. RESULTS: The average operation time per level was 44.7 minutes. Postoperatively, there were significant changes in the angle (from 12.5 to 8.6 degrees, P

A 33-year-old man presented with a rare case of lumbar epidural venous varix causing radiculopathy manifesting as sciatica exacerbated during bowel movements. The left straight-leg raising test was positive and patellar tendon reflex was lost. Lumbar magnetic resonance imaging showed a mass lesion in the epidural space at the L4 level just anterior to the dural sac on the left, appearing as hypointense on T(1)- and hyperintense on T(2)-weighted images, with ring-like enhancement with gadopentetate dimeglumine. He underwent surgery under a preoperative diagnosis of cystic nerve sheath tumor. After left hemilaminectomy, intraoperative ultrasonography showed a low echoic mass lesion ventral to the L4 nerve root. The mass was dark blue with a smooth wall. Tearing of the wall resulted in continuous bleeding. After removal of the lesion, we confirmed that the dura of the nerve root was intact. Histological examination of the surgical specimen confirmed venous tissue. The postoperative course was excellent. Lumbar epidural varix is difficult to diagnose preoperatively. Lumbar epidural varix should be considered if the lesion is smaller on preoperative than intraoperative imaging, or disappears with bleeding cessation, as this may avoid unnecessary widening of the operative field. The correct preoperative diagnosis remains difficult, so we recommend surgical removal and histological confirmation.

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

A 62-year-old male presented with a rare case of ligamentum flavum hematoma manifesting as low back pain and gait difficulty beginning 1 month before consulting our institute. He had no history of lumbar spine surgery or lumbar puncture. However, he might have suffered forgotten back injury while practicing martial arts. Magnetic resonance imaging showed a heterogeneous intensity mass lesion with a cystic component at the L3-4 levels. The lesion was totally removed through a hemilaminectomy. Intraoperative and histological findings confirmed the diagnosis of old hematoma with granulomatous change in the ligamentum flavum. Postoperatively, his low back pain and gait difficulty resolved within a few days.

BEta(2)-glycoprotein I (beta(2)-GPI) is proteolytically cleaved by plasmin in domain V (nicked beta(2)-GPI), being unable to bind to phospholipids. This cleavage may occur in vivo and elevated plasma levels of nicked beta(2)-GPI were detected in patients with massive plasmin generation and fibrinolysis turnover. In this study, we report higher prevalence of elevated ratio of nicked beta(2)-GPI against total beta(2)-GPI in patients with ischemic stroke (63%) and healthy subjects with lacunar infarct (27%) when compared to healthy subjects with normal findings on magnetic resonance imaging (8%), suggesting that nicked beta(2)-GPI might have a physiologic role beyond that of its parent molecule in patients with thrombosis. Several inhibitors of extrinsic fibrinolysis are known, but a negative feedback regulator has not been yet documented. We demonstrate that nicked beta(2)-GPI binds to Glu-plasminogen with K(D) of 0.37 x 10(-6) M, presumably mediated by the interaction between the fifth domain of nicked beta(2)-GPI and the fifth kringle domain of Glu-plasminogen. Nicked beta(2)-GPI also suppressed plasmin generation up to 70% in the presence of tissue plasminogen activator, plasminogen, and fibrin. Intact beta(2)-GPI lacks these properties. These data suggest that beta(2)-GPI/plasmin-nicked beta(2)-GPI controls extrinsic fibrinolysis via a negative feedback pathway loop.

Thoracic disc herniation is less common rather than cervical or lumbar herniation. Cases of sudden onset without trauma are especially rare. Generally, the neurological onset of disc herniation is caused by mechanical cord compression due to a protruded disc, and its onset is usually gradual. Ischemia is also considered as a factor of neurological onset. We report a case of a 78-year-old male with sudden paraplegia while straining at the toilet. T2 weighted MR image on admission showed mild disc protrusion at the level of Th8-9 and intramedullary high signal intensity below the Th8-9 level. We speculate that Valsalva-like maneuver had led to the congestion of vertebral venous plexus or compression of the anterior spinal artery, and spinal ischemia occurred.

BACKGROUND A case of spinal subdural hematoma (SSDH) following subarachnoid hemorrhage (SAH) because of a ruptured internal carotid aneurysm is described. Such a case has never been reported. CASE DESCRIPTION A 52-year-old woman underwent a craniotomy for a ruptured internal carotid aneurysm. A computed tomography scan showed that SAH existed predominantly in the posterior fossa and subdural hematoma beneath the cerebellar tentorium. Intrathecal administration of urokinase, IV administration of fasudil hydrochloride, and continuous cerebrospinal fluid (CSF) evacuation via cisternal drainage were performed as prophylactic treatments for vasospasm. On the sixth postoperative day, the patient complained of severe lower back and buttock pain. Magnetic resonance imaging showed a subdural hematoma in the lumbosacral region. Although the mass effect was extensive, the patient showed no neurologic symptoms other than the sciatica. She was treated conservatively. The hematoma dissolved gradually and had diminished completely 15 weeks later. Her pain gradually subsided, and she was discharged 7 weeks later without any neurologic deficit. CONCLUSION Although the exact mechanism of SSDH in this case is unclear, we speculate that this SSDH was a hematoma that migrated from the intracranial subdural space. Low CSF pressure because of continuous drainage and intrathecal thrombolytic therapy may have played an important role in the migration of the hematoma through the spinal canal. It is important to recognize the SSDH as a possible complication of the SAH accompanied with intracranial subdural hematoma.

Case report: A case of spinal cord injury without radiological abnormality (SCIWORA) at the thoracic level is reported. A 14-year-old girl fell backwards from a low chair and hit her back on the floor. It left her bent forward markedly. After taking a nap, she found herself unable to walk. Neurological examination revealed flaccid paraparesis, hypalgesia below the L-1 level, and bladder and bowel dysfunction. MR imaging revealed marked edema in the thoracic spinal cord. Results and conclusion: The patient was treated conservatively and showed gradual improvement in her symptoms, finally becoming independently ambulant. The spinal cord edema was less pronounced on the follow-up MR imaging. The clinical course and findings of MR imaging in this case demonstrated mid-thoracic SCIWORA caused by hyperflexion of the thoracic spine.

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.

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.

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.

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.

The study was peformed 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.

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.

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.

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.

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.

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. (Neurosurgery 29:137-139, 1991)

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.

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.

Two patients with spinal dural arteriovenous malformations associated with intramedullary changes confirmed by the T2-weighted magnetic resonance imaging (MRI) scans are reported. The characteristics of the MRI findings for these 2 patients were as follows. 1) In the T2-weighted spin-echo image, intramedullary changes observed by MRI were visualized as a high signal intensity area at the level where delay in venous circulation of the spinal cord was revealed by the angiography of the spinal cord. 2) After the obliteration of the arteriovenous shunt by surgical management, intramedullary changes remarkably decreased and disappeared with the disappearance of swelling of the spinal cord observed preoperatively. After that, the atrophy of the spinal cord was shown. 3) The level, extent, and severity of intramedullary changes remarkably decided by the condition of the level where the radiculospinal vein, as the flowing vein, refluxes into the coronal venous plexus and venous flow occurs through the radiculospinal vein into the epidural veins. We suspect that intramedullary changes shown by the T2-weighted MRI scan chiefly represent edema of the spinal cord, caused by an increase in venous pressure due to venous congestion of the spinal cord. MRI is a very useful diagnostic aid to detect intramedullary changes associated with a spinal dural arteriovenous malformation and to evaluate therapeutic results after surgery.

Subependymoma is usually intraventricular; only three cases of spinal cord subependymoma have been reported. The authors encountered a 57-year-old female with a cervical intramedullary subependymoma. The patient had been well until 1967, when she noted numbness in the left arm. Over the next 17 years, weakness of the left leg, numbness of both legs, and gait disturbance slowly progressed. Neurological examination on admission revealed tetraparesis, which was particularly severe on the left side, hyporeflexia of both triceps, hyper-reflexia of both legs, bilateral sensory disturbance below the C5 level, and spastic gait. Myelography and post-myelography computed tomography (CT) showed cord swelling from C5 to Th2 and intramedullary reflux of contrast medium. Contrast-enhanced CT showed marked intramedullary enhancement adjacent to a lowdensity area. Laminectomy was performed and the tumor, which was sharply demarcated and protruding into the cystic cavity, was totally removed. Pathological examination disclosed that it was a typical subependymoma. The postoperative course was uneventful and the symptoms abated. In this as in the three cases previously reported, the tumor was located in the cervical cord of a middleaged patient with a long history of clinical symptoms. The authors emphasize that subependymoma is a benign tumor occasionally found in the spinal cord and that it can be totally removed because of its sharp demarcation from normal tissue.

✓ Four cases of calcification of the cervical ligamentum flavum are reported, all in women over 60 years of age. Neurological findings were not significantly different from those of other cervical compressive diseases. Among radiological examinations, computerized tomography was the most valuable diagnostic tool. Calcification might have been induced by the degeneration or abnormal nutritional state of the ligamentum flavum. Endocrine abnormalities and inflammatory processes might also have been contributory factors.