Role of norepinephrine and excitatory amino acids in edema of the spinal cord after experimental compression injury in rats

The role of norepinephrine and excitatory amino acids in edema of the spinal cord after an acute experimental compression injury was studied in rats. Control rats received the compression injury only. Intraspinal norepinephrine was depleted in one rat group by injection of 6-hydroxydopamine (6-OHDA) into the subarachnoid space to selectively destroy catecholamine neurons and in a third group MK-801 was administered intravenously to block receptors for N-methyl-d-aspartate (NMDA), an excitatory amino acid. Recovery from motor paralysis and suppression of edema of the spinal cord were then compared in the three groups. Significant recovery from motor paralysis was found 12 h after injury in the 6-OHDA-treated rats, compared with the controls, and 24 h after injury in the MK-801-treated rats. Edema of the spinal cord was significantly suppressed for up to 24 h after injury in the 6-OHDA-treated rats. The MK-801-treated rats showed no significant suppression of the edema until 24 h after the spinal cord injury. It was concluded that norepinephrine is primarily involved in the formation of vasogenic edemas, which develop in the early stages after an injury, whereas excitatory amino acids affect the formation of cytotoxic edemas, which develop at a relatively later stage.

Malignant spinal cord compression: prospective study of delays in referral and treatment

OBJECTIVES

To examine the delay in presentation, diagnosis, and treatment of malignant spinal cord compression and to define the effect of this delay on motor and bladder function at the time of treatment.

DESIGN

Prospective study of all new patients presenting to a regional cancer centre with this condition.

SETTING

Regional cancer centre.

SUBJECTS

301 consecutive patients.

MAIN OUTCOME MEASURES

Interval from onset of symptoms to presentation and treatment, delay at each stage of referral, and functional deterioration.

RESULTS

The median (range) delay from onset of symptoms of spinal cord compression to treatment was 14 (0-840) days. Of the total delay, 3 (0-300) days were accounted for by patients, 3 (0-330) days by general practitioners, 4 (0-794) days by the district general hospital, and 0 (0-114) days by the treatment unit. Initial presentation to the regional cancer centre with symptoms of malignant spinal cord compression led to a significant reduction in delay to treatment and improved functional status at the time of treatment. Deterioration of motor or bladder function >=1 grade occurred at the general practice stage in 28% (57) and 18% (36) of patients, the general hospital stage in 36% (83) and 29% (66), and the treatment unit stage in 6% (19) and 5% (15), respectively.

CONCLUSIONS

Unacceptable delay in diagnosis, investigation, and referral occurs in most patients with malignant spinal cord compression and results in preventable loss of function before treatment. Improvement in the outcome of such patients requires earlier diagnosis and treatment.

Case of the month: March 1998--48 year old man with back pain and weakness

A 48 year old man with long history of end stage renal disease (ESRD) and secondary hyperparathyroidism presented with back pain and incontinence. MRI and CT showed T2 expansion with bony destruction and spinal cord compression. Other vertebral bodies showed destructive lesions as well. Microscopic examination showed a brown tumor composed of multinucleated giant cells and bone uninvolved by tumor showed "tunneling" resorption. Brown tumors are an exaggerated form of "local" osteitis fibrosa cystica in patients with ESRD and secondary hyperparathyroidism, but spinal cord compression is rare.

Compression of the upper cervical spinal cord causing symptoms of brainstem compromise. A case report

STUDY DESIGN

A case is reported in which a flexion-induced compression of the upper cervical spinal cord caused symptoms of brainstem compromise in the absence of radiographic evidence of osseous instability.

OBJECTIVES

A 41-year-old woman developed postoperative cervical instability with flexion-induced neurologic symptoms referable to the brainstem. The instability was caused by direct compression at the third cervical vertebral body, which in turn was caused by differential movements between the neuraxis and skeletal elements in the upper cervical spine.

SUMMARY OF BACKGROUND DATA

Pathologic processes at the craniocervical junction may cause brainstem compromise with neurologic symptoms. The mechanism of brainstem involvement is usually either vertebrobasilar insufficiency or direct mechanical compression. In cases where the brainstem is compressed by skeletal elements, the compressing osseous structures usually are the walls of the foramen magnum or the odontoid process, or, less frequently, the atlas or axis vertebrae. Symptoms of brainstem dysfunction caused by dynamic compression at the level of the third cervical vertebra in the absence of hindbrain herniation are unusual and, to the best of the authors' knowledge, have not been described previously.

METHODS

The patient underwent initial examination, evaluation, and periodic follow-up examination with magnetic resonance imaging from the time of her first visit until 26 months after the surgical treatment. The patient experienced postsurgical instability with dynamic compression by the C3 vertebral body, which caused brainstem compromise. Surgical treatment consisted of decompressive C3 corpectomy and fusion of C2 to C6, supplemented by anterior fixation.

RESULTS

After undergoing surgical decompression of C3, reconstruction, and anterior internal fixation of C2 to C6, the patient had dramatic neurologic improvement. Diplopia, paresthesia, and nystagmus disappeared immediately after surgery. Swallowing difficulties, hoarseness, and vertigo improved gradually. At follow-up examination 26 months after surgery, the patient was asymptomatic. Magnetic resonance imaging showed good position of the construct, with no evidence of compression of the spinal cord or brainstem.

CONCLUSIONS

Instability of the cervical spine may result in symptoms of brainstem dysfunction, even in the absence of hindbrain herniation. This instability is explained by the differential movement between the bony structures and neuraxis in the upper cervical region. Diagnosis and adequate management of this instability alleviates the neurologic symptoms and prevents possible hazardous complications.

[Spinal locomotor generators in humans: problems in assessing effectiveness of stimulations]

The paper considers a variant of solving the problem of movement of spinal patients, which is based on the use of the natural location control system contained in the spinal cord. The application areas and electrostimulation parameters which are most effective for locomotion have been determined. The optimum external conditions for walking have been defined.

Cervicomedullary compression: an unrecognized cause of vocal cord paralysis in rheumatoid arthritis

Cervicomedullary compression (CMC) from traumatic, infectious, or congenital processes of the atlanto-axial joint is a known cause of vocal cord immobility. Cervicomedullary compression can also occur from destructive arthritic changes and inflammatory pannus formation at the occipito-atlanto-axial joint in patients with rheumatoid arthritis (RA). We present findings suggesting that CMC in patients with RA is an unrecognized cause of vocal cord immobility. Previously, vocal cord immobility in patients with RA has been assumed to be cricoarytenoid arthritis with joint fixation. We report 3 patients with RA and radiographically demonstrated CMC with vocal cord immobility. One patient had bilateral vocal cord immobility and airway obstruction; 2 patients had unilateral cord paralysis and contralateral paresis without airway compromise. All patients had myelopathy and neck pain in addition to brain stem symptoms. All patients underwent transoral-transpharyngeal decompression of the anterior craniocervical junction with subsequent posterior fusion. These patients demonstrated full return of vocal cord function within 3 months of decompression. We propose that CMC is a cause of vocal cord paralysis in patients with RA that may go unrecognized without appropriate imaging studies of the skull base and physician awareness of symptoms of occipito-atlanto-axial subluxation and/or basilar invagination with brain stem compression. Our results demonstrate that CMC in RA is a potentially reversible cause of vocal cord paralysis.

Dorsal extradural lipoma as cause of spinal claudication. Case report and review of the literature

Extradural spinal lipomas are rare tumorous lesions. "True adult lipomas" have to be histologically differentiated from angiolipomas. The authors describe a case of segmental dorsal lipomas in the lower lumbar spine which led to a clinical apparent spinal claudication. Having reviewed the literature this case is the first ever described. In this case MRI was the diagnostic tool of choice. The tumor could be removed completely via interarcual laminotomy and flavectomy. The clinical outcome was excellent. In differential diagnosis of a spinal claudication this rare cause should be kept in mind when typical osseous changes are absent.

Relationship between severity of spinal cord injury and abnormalities in neurogenic cardiovascular control in conscious rats

Abnormal sympathetic tone after spinal cord injury (SCI) initially results in hypotension and is subsequently associated with autonomic dysreflexia characterized by paroxysmal hypertension and bradycardia in response to noxious or visceral stimuli. To evaluate the effect of a clinically relevant compression model of SCI on cardiovascular control in the early postinjury period, we monitored arterial pressure (AP) and heart rate under control resting conditions and after visceral stimulation (colon distension) in conscious rats for 1 week after clip compression injury of the cord at T5. Rats were randomly allocated into 4 groups (n = 8 each): sham-operated, 20, 35, and 50 g injuries. Only the 50 g injury was associated with significant hypotension (73 +/- 4 mmHg) at 1 day post-SCI when compared to sham-injured rats (91 +/- 3 mmHg). In control rats, colon distention caused a transient pressor response of 16 +/- 3 mmHg and tachycardia. In rats with 20 g 35 g, and 50 g injuries, colon distension 1 day after SCI increased AP by 8 +/- 2, 15 +/- 3, and 21 +/- 1 mmHg, respectively. The hypertensive response correlated with injury severity (r = 0.75; p < 0.0001) and was associated with bradycardia. By 7 days after SCI, only rats with 50 g cord injuries experienced hypertension with reflex bradycardia with visceral stimulation. These data show that dysfunctional cardiovascular control after SCI is correlated with the severity of injury. Mild and moderate compressive SCI result in transient cardiovascular abnormalities which normalize by 1 week. In contrast, more severe injuries are associated with neurogenic hypotension and autonomic dysreflexia.

An 88-year-old woman with tetraparesis after a fall

Images

Cervical spondylotic amyotrophy. Magnetic resonance imaging demonstration of intrinsic cord pathology

STUDY DESIGN

Three case reports.

OBJECTIVE

To elucidate the pathophysiology of cervical spondylotic amyotrophy.

SUMMARY OF BACKGROUND DATA

Cervical spondylotic amyotrophy is the clinical syndrome in cervical spondylosis characterized by severe muscular atrophy in the upper extremities, with an absent or insignificant sensory deficit. Pathophysiology of this particular syndrome has not been well understood.

METHODS

Three cases of cervical spondylotic amyotrophy are presented in which magnetic resonance imaging confirmed the intrinsic cord disease as the cause of the syndrome.

RESULTS

The patients had segmental muscular atrophy of the proximal upper extremities, with an absent or insignificant sensory deficit. After initial disease progression, the symptoms stabilized for years. Sagittal T2-weighted magnetic resonance images showed multi-segmental linear high-signal intensity within the compressed spinal cord. These high-signal intensity lesions appeared to be located at the anterior horns on axial images. The spinal cord compression was less severe in the neck-neutral position, but spinal canal stenosis increased when the neck was extended.

CONCLUSIONS

The results suggest that one pathophysiology of this syndrome may be multisegmental damage to the anterior horns caused by dynamic cord compression, possibly through circulatory insufficiency.

Removal of enterogenous cyst of the cervical spine through anterior approach

Enterogenous cyst is a cause of spinal cord compression. The cyst has been treated surgically through a posterior approach in spite of the location ventral to the spinal cord. We saw two patients who had recurrence at 1 and 3 years after partial removal through this approach. We removed the cyst at the level of the cervical spine in four patients totally or subtotally through an anterior approach. All patients improved neurologically, and there were no signs or symptoms of recurrence at follow-up of from 2 to 13 years (average, 7 years 3 months). It is reasonable to approach the cyst located ventrally to the spinal cord through the anterior route, where the relationship between the cyst wall and the spinal cord can be viewed directly.

A surgically placed epidural catheter in a patient with spinal trauma

PURPOSE

To report the successful perioperative anaesthetic and analgesic management of a spinal trauma patient with a surgically placed epidural catheter.

CLINICAL FEATURES

A 15-yr-old adolescent woman sustained an unstable spinal column injury with an incomplete neurological deficit following a high speed motor vehicle accident. She was scheduled for spinal decompression and stabilisation through a left thoracoabdominal approach. Balanced general anaesthesia was undertaken. Prior to closure, a multi-orifice epidural catheter was surgically placed under direct vision 5 cm into the anterior epidural space. The catheter was then tunnelled out through the psoas muscle and secured in place. Combined epidural-general anaesthesia was then initiated for the duration of the case using 5 ml bupivacaine 0.25% after an initial test dose of 3 ml lidocaine 1.5% with epinephrine. An infusion of bupivacaine 0.10% and fentanyl 5 micrograms.ml-1 at 8 ml.hr-1 using patient controlled epidural analgesia (PCEA) provided excellent postoperative pain control for four days. She had an uncomplicated postoperative course.

CONCLUSION

A surgically placed epidural catheter provided excellent, safe, perioperative anaesthesia and analgesia in this patient with unstable spinal trauma.

Concomitant tuberculosis and pyogenic infection of the cervical spine. A case report

STUDY DESIGN

This case report describes a middle-aged woman with concomitant tuberculosis and pyogenic infection of the cervical spine.

OBJECTIVE

To describe an unusual case of concomitant tuberculosis and pyogenic infection of the cervical spine.

SUMMARY OF BACKGROUND DATA

Neither tuberculosis nor pyogenic spondylitis of the cervical spine is a common disorder. This case report describes a concomitant infection of C3-C4 in an otherwise healthy patient. To the authors' knowledge, such a case has never been reported.

METHODS

This 52-year-old woman had spontaneous neck pain and myelopathy. Radiologic examination revealed the presence of an epidural abscess with destruction of C3-C4 vertebral bodies.

RESULTS

Anterior decompression and fusion were performed, followed by therapy with antituberculosis drugs and antibiotics. The patient completely recovered. A follow-up radiograph revealed that solid fusion had been achieved.

CONCLUSION

A case of concomitant tuberculosis and pyogenic infection of the cervical spine is presented. The possibility of this differential diagnosis should be considered, especially in areas of endemic tuberculosis. Examination of biopsy samples for histologic and bacteriologic findings is important to confirm this diagnosis. Radical debridement and combination therapy are strongly recommended to treat patients with this combination of infections.

Spinal cord decompression via microsurgical anterior foraminotomy for spondylotic cervical myelopathy

A microsurgical anterior foraminotomy, as a direct decompressive and motion-segment preserving technique, has been developed by the author and used successfully in many patients with spondylotic cervical radiculopathy for the past several years. From the author's increasing experience with anterior foraminotomy for cervical radiculopathy, it was noted that the spinal cord canal could be effectively decompressed utilizing the holes of anterior foraminotomy. This new technique accomplishes widening of the spinal cord canal anteriorly to the spinal cord in the transverse and longitudinal axis by direct removal of the compressive lesions through the holes of unilateral anterior foraminotomies. This technique does not require bone fusion or postoperative immobilization. 14 patients with spondylotic cervical myelopathy have been treated by this technique. 9 were males and 5 were females, and all presented with cervical myelopathy with or without radiculopathy. Age ranged from 32 to 68 years (median 55 years). 6 patients had spinal cord compression at one level, six patients experienced it at two levels, and two patients had it at three levels. Postoperatively, all patients showed improvement in their myelopathic symptomatology as well as gaining relief of their radicular symptoms. Corresponding MR scans confirmed satisfactory anatomical decompression in all patients. Postoperative dynamic roentgenograms confirmed spinal stability in all patients as well. Patients stayed in the hospital overnight postoperatively, and cervical braces were not used. This new surgical technique has shown excellent clinical outcomes with fast recovery and adequate anatomical decompression in 14 patients with spondylotic cervical myelopathy.

Surgical treatment of thoracic arachnoiditis with multiple subarachnoid cysts caused by epidural anesthesia

We report on a 36 year-old woman who had sensorimotor and sphincter dysfunction 0.5 day after having an epidural anesthesia to deliver her baby. The patients' neurological deficits recovered gradually and she could walk without support 1.5 months after the operation. However, her neurological function deteriorated 4 months after anesthesia and a magnetic resonance imaging (MRI) study revealed spinal arachnoiditis with multiple subarachnoid cysts at the T5-7 levels. Surgical treatment consisted of lysis of adhesions and wide opening of the subarachnoid cysts. Her motor function improved after operation and she could walk without support after a 1 year follow-up. However, her sphincter and sensory abnormalities persisted for the most part. The literature on the surgical treatment of arachnoiditis with myelopathy is reviewed and the surgical indications are discussed.

Spinal cord compression by heterotopic ossification associated with pseudohypoparathyroidism

This report describes a 37-year-old man presenting with a gait disturbance due to spastic paraparesis. Physical findings showed typical features of Albright's hereditary osteodystrophy, including short stature, obesity, brachydactyly and dental hypoplasia. He was diagnosed as having pseudohypoparathyroidism type Ia, on the basis of his hypocalcaemia, hyperphosphataemia, increased plasma level of parathyroid hormone (PTH), and the unresponsiveness to exogenous PTH loading of his urinary excretion of both nephrogenous cyclic adenosine monophosphate and phosphate. Magnetic resonance imaging and myelographic computed tomographic scans clearly demonstrated severe compression of the spinal cord at T 9/10 by tumour-like ossifications of the paravertebral ligaments. Neurosurgical decompression therapy was, therefore, performed to alleviate his spastic paraparesis. This was a rare case of pseudohypoparathyroidism complicated with spinal cord compression caused by ectopic ossification of the ligaments.

A classification scheme for paradoxical vocal cord motion

Paradoxical vocal cord motion (PVCM) is characterized by the inappropriate adduction of the true vocal cords during inspiration. Multiple causes have been proposed for this group of disorders, which share the common finding of mobile vocal cords that adduct inappropriately during inspiration and cause stridor by approximation. Management of this group of disorders has been complicated by the lack of a classification scheme to include all types of PVCM. We propose that PVCM be classified according to its underlying etiology and recognize the following causes of the disorder: 1. brainstem compression; 2. cortical or upper motor neuron injury; 3. nuclear or lower motor neuron injury; 4. movement disorder; 5. gastroesophageal reflux; 6. factitious or malingering disorder; 7. somatization/conversion disorder. Case reports are presented to illustrate the characteristic features and diagnostic evaluation used in assessing patients with PVCM. Management varies depending on the cause of PVCM and entails speech therapy, pharmacologic therapy, behavioral modification, and/or surgical intervention. Recognition of the multiple causes of PVCM allows otolaryngologists to formulate well-directed diagnostic evaluation and treatment.

[The late-period results of surgical treatment for trauma to the cervical spine and spinal cord]

Seven patients with late-stage spinal cord injury (SCI) at the cervical level were operated on 2 to 11 months following the accident. To assess the preoperative status and the results of surgical treatment, the ASIA motor scoring system was utilized. In 6 cases anterior decompression was combined with a strut graft fusion, one patient was managed via posterior approach, i.e. C7 laminectomy, followed by myelotomy and drainage of the intramedullary cyst. Segmental motor improvement was noted in 3 patients. In one patient minor sensory improvement in the sacral area was documented. We believe even minor (i.e. segmental) neurological improvement can significantly alter the functional outcome. Our sense is that an evidence of the spinal cord compression even in late-stage SCI should be considered to be an indication for surgery. In patients with complete SCI, the goal of surgical treatment is segmental motor improvement. If muscular strength in the upper extremities is preserved, surgery is thought to be optional.

Tetraparesis following dental extraction: case report and discussion of preventive measures for cervical spinal hyperextension injury

This concerns a patient with compression myelopathy following passive hyperextension of the cervical spine during a dental procedure. Although he had been asymptomatic prior to the procedure, subsequent cervical spinal imaging revealed advanced spondylosis and spinal stenosis. Spinal stenosis is often asymptomatic for a long time. However, when radiculomyelopathy occurs after minor trauma to the head or neck, the patient is often found to have spinal stenosis. Specifically, hyperextension of a cervical spine with spondylotic changes can lead to compression myelopathy. Acquired spinal stenosis correlates positively with aging. As the size of the elderly population continues to increase the prevalence of cervical spondylotic radiculo-myelopathy will likely increase as well. Since appropriate precautions against potential neurologic damage can be undertaken, we suggest radiographic screening for pre-existing spinal stenosis prior to a procedure requiring hyperextension of the neck. Preventive measures for individuals with asymptomatic spondylotic changes and education of all health-care professionals to avoid abrupt or prolonged hyperextension of the cervical spine is emphasized.

Cervical spondylotic amyotrophy associated with Hirayama's disease

A 47-year-old man with Hirayama's disease who developed cervical spondylotic amyotrophy (CSA) is presented. The patient had noted weakness and atrophy of hand and forearm muscles bilaterally at the age of 16. At the age of 40, he developed proximal muscle atrophy and weakness bilaterally after 20 years of a non-progressive state. Myelography and computed tomography (CT)-myelography revealed that ventral cord compression at multiple levels of C4-7 vertebral bodies was increased when the neck was extended. The clinical diagnosis was CSA associated with Hirayama's disease. To our knowledge, this is the first such case to be reported.

Paraparesis caused by a bilateral cervical synovial cyst

We describe a 64-year-old man who suffered from rapidly progressive paraparesis. At operation the cervical cord of the patient was found to be displaced anteriorly due to compression caused by an epidural synovial cyst. The cyst was located bilaterally on the dorsolateral aspect of both CVII facet joints. The rapid development of paraparesis in this patient can, thus, be explained by the enlargement of the cyst on both sides of the spinal cord. After microsurgical removal of the cystic tumor, the recovery of the patient was good. Cervical epidural cysts are extremely rare, and only anecdotal cases have been reported in the literature. Among all previously described patients the present case is unique due to the bilateral location of the cyst.