Comparative spinal neurotoxicity of prilocaine and lidocaine

BACKGROUND: Reports of major and minor sequelae following lidocaine spinal anesthesia have generated interest in an alternative short-acting intrathecal agent. Of the available anesthetics suitable for short-duration spinal anesthesia, prilocaine is perhaps the most promising agent. However, data comparing the neurotoxicity of these agents are lacking. Accordingly, the present experiments investigate whether prilocaine and lidocaine differ with respect to sensory impairment and histologic damage when administered intrathecally in the rat. METHODS: Ninety rats were divided into three groups to receive an intrathecal infusion of 2.5% prilocaine in saline, 2.5% lidocaine in saline, or normal saline. The animals were assessed for persistent sensory impairment 4 days after anesthetic administration using the tail-flick test. Three days later, the animals were killed, and specimens of the spinal cord and nerve roots were obtained for histopathologic examination. RESULTS: Prilocaine and lidocaine produced equivalent elevations in tail-flick latency that differed significantly from saline. Histologic injury scores with prilocaine were greater than with lidocaine, but this difference did not reach statistical significance. CONCLUSIONS: The propensity for persistent functional impairment or morphologic damage with intrathecal prilocaine is at least as great as with lidocaine. Although the substitution of prilocaine for lidocaine may reduce the incidence of transient neurologic symptoms, it is unlikely to reduce the risk of actual neural injury. This discrepancy may indicate that transient neurologic symptoms and neurologic deficits after spinal anesthesia are not mediated by the same mechanism.     

Neurologic complications of surgery for cervical compression myelopathy.

Neurologic complications resulting from surgery for 384 cases of cervical myelopathy (cervical soft disc herniation, spondylosis, ossification of the posterior longitudinal ligament) were reviewed. Surgical procedures performed included 134 anterior interbody fusions (Cloward or Robinson-Smith technique), 70 subtotal corpectomies with strut bone graft, 85 laminectomies, and 95 laminoplasties. Twenty-one patients (5.5%) sustained neurologic deterioration related to surgery. The deterioration was classified into two types on the basis of the neurologic signs observed: deterioration of spinal cord function or of nerve root function. Manifestations of the former varied from weakness of the hand to tetraparesis. Paralysis of the deltoid and biceps brachii muscles was an exclusive feature of deterioration in the nerve root group. Causes of this paralysis included malalignment of the spine related to graft complications, and a tethering effect on the nerve root following major shifting of the spinal cord after decompression. The causes of deterioration of the cord function included spinal cord injury during surgery, malalignment of the spine associated with graft complication, and epidural hematoma.     

Cervical pyogenic spondylodiscitis: 4 cases report and a review of the literature

We report 4 cases of cervical spondylodiscitis presenting neurological and/or neuroradiological abnormalities. Such a lesion is rare in the cervical spine of adults, but should be suspected when the patient has radiculopathy and/or myelopathy associated with inflammatory signs. We discussed the clinical characteristics and the procedures of the diagnosis and treatment of cervical spondylodiscitis. Early and definitive diagnosis can be achieved by cervical X-ray, MR imaging and biopsy. It is very important to evaluate the pyogen for the lesion by needle biopsy. When the patient has the compression of the spinal cord and/or nerve roots and the neurological findings of radiculopathy and/or myelopathy, surgical exploration and decompression of the spinal cord and/or nerve roots should be carried out as soon as possible. Anterior debridement and fusion should be performed using the effective antibiotics. We were able to achieve good prognosis by treatment following this procedure of diagnosis in the four cases of cervical spondylodiscitis mentioned.     

Posterolateral approach to ruptured median and paramedian cervical disk

The trend toward anterior diskectomy for median and paramedian cervical disk rupture has tended to obscure progressive development of the posterolateral approach to these lesions. Modifications of surgical technique from the classic posterior approach have allowed direct access to these lesions, provided for satisfactory decompression of the spinal cord, especially when there is associated spondylosis, and avoided all of the disadvantages of anterior disk surgery. Of 28 patients operated on since 1950, 26 have had significant preoperative myelopathy or myeloradiculopathy. Two patients with obvious spinal cord compression and massive myelographic defects had no neurologic deficit. Improvement has been observed in every patient; 16 patients have had full recovery, and 8 others have had minor residual symptoms and asymptomatic signs. Although four patients have been lost to follow-up, they were all seen at least once after operation. No instance of increased deficit has been seen postoperatively, in contrast to the author's experience with spondylotic myelopathy. Postoperative contrast studies, which have now been performed on eight patients, confirm satisfactory excision of these lesions and decompression.     

Spinal cord and nerve root monitoring during surgical treatment of lumbar stenosis

The author describes application of intraoperative neurophysiologic monitoring to surgical treatment of lumbar stenosis. Benefits of somatosensory and motor evoked potential studies during surgical correction of spinal deformity are well known and documented. Free-running and evoked electromyographic studies during pedicle screw implantation is an accepted practice at many institutions. However, the functional integrity of spinal cord, cauda equina, and nerve roots should be monitored throughout every stage of surgery including exposure and decompression. Somatosensory evoked potentials monitor overall spinal cord function. Intraoperative electromyography provides continuous assessment of motor root function in response to direct and indirect surgical manipulation. Electromyographic activities observed during exposure and decompression of the lumbosacral spine included complex patterns of bursting and neurotonic discharge. In addition, electromyographic activities at distal musculature were elicited by impacting a surgical instrument or graft plug against bony elements of the spine. All electromyographic events provided direct feedback to the surgical team and were regarded as a cause for concern. Simultaneously monitored evoked potential and electromyographic studies protect spinal cord and nerve roots during seemingly low-risk phases of a surgical procedure when neurologic injury may occur and the patient is placed at risk for postoperative myelopathy or radiculopathy.     

Neurophysiological monitoring for safe surgical tethered cord syndrome release in adults

BACKGROUND: Release of tethered spinal cord by sectioning of the filum terminale carries a significant risk of injury to the neighboring motor and sensory nerve roots. Intraoperative neurophysiological monitoring techniques can help to minimize these adverse neurologic outcomes. METHODS: We performed a retrospective review of 67 consecutive patients undergoing tethered cord release. We excluded 52 pediatric patients which limited our study to 15 adult patients treated during a four year period, including patients with a thick filum, low lying conus, myelomeningocele, filum tumor, spinal cord malformation, and/or lipoma. Clinical outcomes were determined from postoperative follow-up visits. Two patients were lost to follow up and were excluded from the clinical outcome analysis. Electrical stimulation of the filum terminale and lumbo-sacral nerve roots in conjunction with electromyogram (EMG) recording was performed intraoperatively. RESULTS: The mean electrical threshold for EMG response during stimulation of the filum terminale was 37.1 volts (V), range 15 to 100 V. In comparison, the lowest threshold obtained by direct stimulation of the ventral nerve roots was a mean of 1.46 V, with a range of 0.1 to 7 V. More than 70% of the patients studied demonstrated a filum to motor root threshold ratio of 100:1 or greater. No patient developed new neurologic symptoms or signs postoperatively. Bowel and bladder function improved in 46% of patients, back pain in 39% and motor function in 31%. Eight percent reported decline in bladder control and worsening back pain postoperatively. CONCLUSIONS: The often dramatic difference in the threshold of the filum terminale and adjacent motor nerve roots (100:1) helps to identify, isolate, and safely section the filum terminale. Tethered cord release using intraoperative neurophysiological monitoring is safe and in the majority of cases leads to improvement or at least, stabilization of neurologic function. Monitoring prevented intraoperative nerve root injury that might have resulted in immediate onset of new neurologic deficits caused by the surgical procedure.     

The variable presentations of craniocervical and cervical dural arteriovenous malformations

The authors reviewed four patients with dural arteriovenous malformations in the upper spinal axis. Two were at the foramen magnum and two were lower cervical. The patients presented with subarachnoid hemorrhage, a slowly progressive cervical myelopathy, a rapidly progressive thoracic myelopathy, and tinnitus with a sixth nerve palsy. This report emphasizes the importance of studying both the intracranial dural vessels as well as the supply to the cervical spine in searching for a spinal arteriovenous malformation. Subarachnoid hemorrhage with negative cerebral angiography requires spinal angiography if there are any signs or symptoms suggesting cord or nerve root dysfunction. Embolization by an endovascular approach resulted in an angiographic cure in two patients. A combination of embolization and surgery resulted in obliteration of the arteriovenous malformation in one patient. Embolization achieved a clinical cure in one patient, and clinical improvement in two patients.     

腰椎间盘术后椎间盘炎的诊断与治疗

目的：介绍腰椎间盘术后椎间盘炎的临床特点,讨论治疗方法。方法：对１３例术后椎间盘炎临床资料回顾,分析常见诊治失误原因。依靠临床体征、血沉、Ｃ—反应蛋白、Ｘ线、ＣＴ或ＭＲＩ建立早期诊断。非手术治疗治愈１０例,手术治疗治愈３例。结果：术后１１例随访６～３６个月。９例恢复原工作,４例遗有慢性腰痛或腰椎活动受限,２例不能胜任体力劳动。结论：早期诊断应重视术后再发剧烈腰痛的特殊体征。血沉、Ｃ—反应蛋白是提示感染或观察疗效的指标。Ｘ线、ＣＴ、ＭＲＩ有诊断价值。多数患者经严格卧床,大剂量广谱抗生素治疗效果满意。保守无效,炎症扩散出现相应临床症状者,应行病灶清除术。     

A comparative study of surgical approaches for cervical compressive myelopathy

Since 1986, the authors have used anterior decompression and fusion to treat patients with one- or two-level lesions without spinal canal stenosis (Group A) and laminoplasty for patients with more than three-level lesions or spinal canal stenosis (Group P). The aim of this study was to compare surgical outcomes of anterior and posterior approaches for patients with cervical myelopathy because of spondylosis and disc herniation and to determine the cause of poor neurologic recovery after surgery. One hundred thirty-six patients were followed up for an average of 5.6 years. There were no significant differences in gender, preoperative neurologic deficits, axial symptoms, or duration of symptoms before surgery between the two groups. Mean recovery rates for disc herniations were 71.1% and 71.9% in Groups A and P, respectively. For spondylosis, mean recovery rates were 49.0% and 58.6% in Groups A and P, respectively. There were no differences in recovery rate for patients with either spinal disorder between Groups A and P. The neurologic recovery of patients with kyphotic spinal cord was inferior to that of patients with lordotic or straight spinal cord. It is possible that acquisition and maintenance of lordosis result in improvement of clinical outcomes after surgery for patients with myelopathy.     

前路钩椎关节切除在颈椎病治疗中的初步应用

目的探讨前路钩椎关节切除治疗脊髓型伴神经根型颈椎病的有效性和安全性.方法 2002年3月～2004年7月,收治脊髓型伴神经根型颈椎病9例,男5例,女4例,年龄38～66岁.病程11～63个月.其中单侧神经根受压6例,双侧神经根受压3例.双下肢肌力3级,行走困难3例;双下肢肌力4级,行走不稳或缓慢6例.采用前路钩椎关节切除神经根减压,椎间盘切除脊髓减压,钛网植骨钢板螺钉内固定术.结果术中无椎动脉损伤.患者均获随访3～16个月,根性神经痛消失7例,2例仍残留局部酸胀疼痛.6例双下肢肌力4 级,3例双下肢肌力4级.CT扫描或X线片示椎间孔均有扩大,MRI显示脊髓及神经根压迫解除.结论钩椎关节切除能对神经根直接减压.熟悉局部解剖,掌握手术技巧是避免损伤椎动脉的关键.     

Unusual appearance of an en plaque meningioma of the cervical spinal canal. A case report and literature review

STUDY DESIGN: A case report of a patient with cervical spinal cord and nerve root compression caused by a meningioma en plaque together with calcification of the posterior longitudinal ligament is presented,with a review of the literature. OBJECTIVE: To present the diagnosis of a calcified dural meningioma en plaque, with extradural extension into the ligamentum flavum, in a woman with cervical myelopathy and neuropathy. SUMMARY OF BACKGROUND DATA: This case demonstrates that the cervical spine can be involved in dural meningioma en plaque with calcifications, in a manner mimicking ossification of the ligamentum flavum, which has never been previously reported. METHODS: A patient presenting with cervical cord and nerve root compression caused by ossification of the posterior longitudinal ligament and a concurrent calcified dural meningioma en plaque was treated surgically and has made a gradual recovery. Imaging studies,surgical findings, and histopathologic evaluation were analyzed to support the diagnosis. RESULTS: At surgery, ossification of the posterior longitudinal ligament was noted, along with a calcified lesion involving the posterior cervical dura and the adjacent ligamentum flavum. A calcified meningioma was diagnosed by histopathologic examination of the dural-based lesion. CONCLUSION: Although previously not described, the diagnosis of calcified dural meningioma en plaque should be considered in all patients presenting with spinal cord and/or nerve root compression,even at cervical levels. Although ossification of the posterior longitudinal ligament and ossification of the ligamentum flavum are more common etiologies of partially circumferential spinal calcification, dural-based meningiomas with extension into the surrounding ligaments demand early recognition because they can be associated with a poorer prognosis.     

Myelography in the late postoperative period in patients subjected to anterior cervical decompression and fusion

Summary During a 13 year period, 286 patients with cervical disc herniation and/or spondylotic spurs, were subjected to anterior decompression and vertebral interbody fusion with autologous bone.Twenty patients were re-admitted in the late postoperative period due to recurrent radicular symptoms and/or signs of myelopathy. In these patients myelography was performed again. In 14 patients spinal cord compression and/or nerve root involvement at a new level was visualized. At the operated level, however, the myelograms demonstrated a smooth anterior wall in the spinal canal.The series confirms the safety, effectiveness and reliability of the Cloward procedure in achieving long term spinal cord and nerve root decompression, and a solid vertebral interbody fusion.     

Myelopathy hand. New clinical signs of cervical cord damage

A characteristic dysfunction of the hand has been observed in various cervical spinal disorders when there is involvement of the spinal cord. There is loss of power of adduction and extension of the ulnar two or three fingers and an inability to grip and release rapidly with these fingers. These changes have been termed "myelopathy hand" and appear to be due to pyramidal tract involvement. The characteristic nature of the signs permit the distinction between myelopathy and changes due to nerve root or peripheral nerve disorder. The clinical significance of these signs has been assessed against other tests and their value in management is discussed.     

Isolated subaxial cervical spine stenosis in achondroplasia

Although isolated subaxial cervical spine stenosis in achondroplasia is less common than narrowing at the foramen magnum, thoracolumbar junction, or lumbar spine, it should be recognized as a distinct entity. These congenital changes usually become symptomatic when combined with degenerative changes in early adult life. Yearly monitoring of adult achondroplastic patients for signs and symptoms of cervical myelopathy or radiculopathy is recommended. When this develops, early surgical decompression should be considered, as these patients generally do not respond well to nonoperative treatment. The altered anatomy and small size make these cases particularly challenging. A thorough history and examination and complete diagnostic testing are necessary to gain an understanding of the exact etiology of the symptoms. Wide laminectomies and foraminotomies are then usually required to decompress the spinal cord and nerve roots. Fusion using internal fixation may be required to stabilize the spine if excessive bone is removed. (Curr Surg 57:354-356)     

Cervical myelopathy in patients with congenital cervical block vertebrae

Summary Thirty-two patients with congenital cervical block vertebrae are reviewed. Twenty-nine patients had single level fusion, one had two-level fusion, and the remaining two had multilevel fusion. Eighteen patients had cervical myelopathy; five of these had related trauma and 13 had no history of trauma. The five patients who had cervical myelopathy following trauma underwent magnetic resonance imaging (MRI); three of them had abnormalities in the spinal cord at the segment adjacent to fusion. In all five patients the symptoms and signs were attributed to the segment adjacent to fusion. Myelography, computed tomographic myelography and MRI were performed in 11 of the 13 patients with cervical myelopathy without trauma. In 9 of them maximum compression of the spinal cord was not seen at the segment adjacent to fusion. The major factor contributing to cervical myelopathy was associated spinal canal stenosis. Seven patients with cervical myelopathy without history of trauma were treated surgically, six of whom had spinal canal stenosis treated by enlargement of the spinal canal: subtotal corpectomy and arthrodesis was performed in three, and open-door expansive laminoplasty in three. Anterior interbody arthrodesis was performed in one patient without spinal canal stenosis. All recovered from the myelopathy postoperatively. When a trauma occurs, it concentrates stress at the segment adjacent to fusion, resulting in possible spinal cord injury. On the other hand, when there is no trauma, spinal canal stenosis is the principal factor contributing to cervical myelopathy.     

Successful treatment of a group of spinal cord arteriovenous malformations by interruption of dural fistula

As demonstrated by selective spinal cord arteriography, over 80% of spinal cord arteriovenous malformations (AVM's) occupy a predominantly extramedullary position. Current therapy frequently requires surgical stripping of the long dorsal intradural vessel(s) from the underlying spinal cord over many cord segments. The authors report six patients with a dural arteriovenous fistula fed by a cluster of abnormal epidural arteries. These vessels, which surrounded and were embedded into the dural covering of a thoracic nerve root, drained into a long sinuous intrathecal paramedullary vein(s). The angiographic and surgical appearance of the intradural component of these lesions was identical to that of lesions previously classified as Type I AVM's of the spinal cord. All patients had symptoms and signs of myelopathy. In five patients, surgery was limited to coagulation and excision of the extradural vessels and division of the intradural arterialized vein. Progressive improvement began within days following surgery. No residual abnormality was demonstrated by postoperative selective spinal cord arteriography, which was performed in all five patients. The findings support those of Kendall and Logue, that surgery restricted to elimination of the arteriovenous fistula at the intervertebral foramen is curative, and that more extensive surgery is unnecessary for this subgroup of AVM's of the spinal cord. These lesions comprise a sizable percent of all spinal AVM's. Resolution of myelopathy in these patients supports the hypothesis that venous hypertension causes chronic progressive myelopathy.     

Specificity of CT myelographic findings in cervical nerve root symptoms

Summary In a series of 62 patients with cervical nerve root symptoms CT myelography of the cervical spine revealed specific radiological signs in 24 patients. These signs are: stenosis of the spinal canal, nerve root swelling and/or soft disc herniation. Disc bulging or spondylotic encroachment with only partial narrowing of the myelographically visible part of the foramen, and often unilateral flattening of the cord is considered clinically insignificant. A normal appearance of cord and nerve roots was seen in 22 patients.     

The symptomatic incompetent cervical intervertebral disc

A series of 16 patients with symptoms such as pain in the neck, occiput, shoulder and arm; numbness in the hands; and/or difficulty in walking, is described. Neurological examination of the upper extremities disclosed signs of nerve roots dysfunction in 5 patients and long tract signs in 12, whereas examination of the lower extremities disclosed long tract signs in every patient. Positive contrast cervical myelograms suggested mild posterior bulging of one or two intervertebral discs in every patient, but computed tomographic myelograms invariably demonstrated a coincident narrow cervical spinal canal, thus revealing the true compressive potential of the aforementioned mild disc protrusion on the spinal cord. All patients underwent anterior cervical microdiscectomy of the offending disc or discs, which were found to be degenerated. No case of frank rupture of the anulus was identified. Response to treatment was graded as excellent in 12 patients, who had complete relief of symptoms, and good in 4 patients, who had mild residual complaints. This study suggests that incompetence (bulging) of a cervical intervertebral disc may acquire important clinical significance in the presence of a narrow spinal canal by compressing the spinal cord and the corresponding nerve roots. Surgical removal of the diseased disc may result in restoration of neurological function.     

Myélopathies aiguës transverses : myélopathie inflammatoire ou ischémique ?

The rapid development of paraparesis or tetraparesis combined with a bilateral sensory deficit that has a clearly defined rostral border and bladder dysfunction are the principal features of acute transverse myelopathy. Acute partial transverse myelopathy is far much more frequent: its symptoms are asymmetric, sometimes unilateral, and sensory deficit may predominate. An urgent MRI is required to exclude acute spinal cord compression. Diagnosis of ischemic acute transverse myelopathy includes the following elements: sudden onset, neurologic symptoms compatible with infarction in the anterior spinal artery area (by far the most frequent location for spinal cord infarction), and presence of a specific cause of spinal cord ischemia. In all other cases where it is difficult to distinguish spinal cord infarction from myelitis, analysis of the cerebrospinal fluid is essential. Most cases of inflammatory acute transverse myelopathy can be linked to a defined cause. Multiple sclerosis is a major cause of partial acute transverse myelopathy. MRI lesions are usually small, located in the lateral or posterior part of the spinal cord. Diagnostic elements include multiple lesions of multifocal demyelination on the cerebral MRI, oligoclonal bands in the cerebrospinal fluid, and the absence of clinical or laboratory abnormalities that suggest systemic disease. Neuromyelitis optica, also known as Devic's disease, has often been considered a variant form of multiple sclerosis. Recent immunologic studies confirm the hypothesis that it is a distinct entity. Infectious transverse acute myelitis is often of viral origin. It may result from direct viral stress but more frequently follows immunologically-mediated indirect stress. This acute parainfectious myelitis, like postvaccinal myelitis, may be considered as a spinal single-focus form of acute disseminated encephalomyelitis (ADEM). It is important to distinguish the latter from an initial episode of multiple sclerosis, because their prognosis and treatment differ.