A case of congenital intraspinal neuroblastoma

A case of congenital intraspinal neuroblastoma with paraplegia in a newborn is described, and a review of previously reported cases is presented. Calcification within the spinal canal and abdominal mass was noted. At age 75 days, the patient underwent a resection of almost the entire retroperitonial tumor. A magnetic resonance scan showed hepatic metastasis, and chemotherapy was changed to a more intensive regimen. The liver metastasis disappeared; however, neurological signs persisted. A literature review of 38 cases showed 26 patients had a laminectomy and 12 patients did not. Treatment with or without laminectomy was associated with a poor prognosis for neurological recovery, suggesting cord compression must occur antenatally, and irreversible damage occurs before birth. Congenital intraspinal neuroblastoma has a relatively good prognosis (survival rate, 91.9%), although complete neurological recovery is highly unusual. Based on these findings, the authors conclude that a laminectomy is not indicated for those patients.     

Extra osseous tumors of the spine in children and adolescents. Spinal complications

PURPOSE OF THE STUDY: The delay in diagnosis of spinal tumors is not rare. The chief complaint may include pain, walking disability, and spinal or limb deformities. The purpose of our study is to analyze the spinal deformities associated with non osseous intraspinal tumors, to assess the complications of treatment, and to set out a preventive protocol. MATERIALS: We reviewed retrospectively 40 consecutive cases of non osseous intraspinal tumors treated between 1972 and 1991. There were 32 intradural, 2 extradural, and 6 intra and extradural combined tumors. At the first consultation, the age ranged between 4 months and 15 years, and only 16 patients showed neurologic deficit. Spinal deformity existed in 9 patients, 7 of which had no neurologic deficit. All the tumors were treated surgically. Laminectomy was done in 28 cases, and osteoplastic laminotomy in 12 cases. The number of levels included in the laminectomy ranged from 3 to 18. Bilateral arthrectomy at least at one level was undertaken in 15 cases. A postoperative brace was worn in all cases for an average period of 4 months. An adjuvant radiotherapy was undertaken in 12 cases for an incomplete resection. METHODS: The incidence and pattern of spinal deformity was assessed before tumor treatment and ultimately after laminectomy or osteoplastic laminotomy (or laminoplasty). RESULTS: Among the 9 cases with preexisting spinal deformity, the curve magnitude increased after laminectomy in 4. A kyphotic, kyphosoliotic or scoliotic deformity developed in 18 cases after surgery for tumor resection. Among these 18 patients, only one had had an adequate osteoplastic laminotomy. The treatment of spinal deformities was surgical in 12 cases, and done by either posterior or anterior and posterior combined arthrodesis. DISCUSSION: Spinal deformity may be the main complaint of a patient who has intraspinal tumor. Prevention of postlaminectomy spinal deformity is mandatory, and could be done by osteoplastic laminotomy and the use of a brace during a minimum period of 4 to 6 months after surgery. CONCLUSION: Diagnosis of intraspinal tumors in children and adolescents should be done early, and laminoarthrectomy should be replaced by osteoplastic laminotomy.     

The impact of occupation on self-reported cardiovascular morbidity in western Germany: gender differences

Two hundred one consecutive patients with cancer pain who received intrathecal pain treatment between 1985 and 1993 were included in this retrospective study undertaken to test the hypothesis that epidural metastasis is a common cause of "refractory" cancer pain and that its presence may affect the efficacy and the complication rates of intraspinal pain treatment. Fifty-seven (approximately 28%) patients were investigated by metrizamide myelography, computerized tomography (CT), magnetic resonance imaging (MRI), laminectomy, or neurohistopathology. Epidural metastases were found in 40 (70%) and spinal stenosis in 33 (approximately 58%); 7 patients with total and 26 with partial occlusion of the spinal canal. Presence of epidural metastasis affected catheter insertion complications, daily dosages, and complications of the intrathecal pain treatment only when it was associated with spinal canal stenosis (partial or total). During the period of the intrathecal treatment, the patients with confirmed epidural metastasis and total spinal canal stenosis needed significantly (P < 0.05) higher daily doses of opioid (means = 77 +/- 103 versus 22 +/- 29 mg) and intrathecal bupivacaine (means = 65 +/- 44 versus 33 +/- 20 mg) and had significantly (P < 0.05) higher rates (14% versus 0%) of radicular pain at injection and poor distribution of analgesia than those without epidural metastasis and spinal canal stenosis. In contrast, the rate of occurrence of post-dural puncture headache was significantly (P < 0.05) lower in patients with partial (4%) and total (14%) spinal stenosis than in those without (29%). Unexpected paraplegia occurred in four patients and was due to accidental injury during attempted dural puncture (N = 1) and collapse (due to cerebrospinal fluid leakage leading to "medullary coning" of an unknown epidural metastasis (N = 3).     

Pulmonary complications in AIDS: CT appearances

We investigated 33 cervical spinal cord injury patients (25 males and eight females) without bony injury. Patients whose neurologic recovery had reached a plateau and who had evidence on imaging of persistent spinal cord compression were considered candidates for surgical decompression. When imaging did not show spinal cord compression or patients were maintaining a good neurologic recovery from the early days after injury, we pursued conservative treatment. Age at injury varied from 20 to 76 years (mean, 55.6). Average follow-up was 31 months. Twelve patients were treated conservatively (Group 1). Groups 2 and 3 had surgery. Group 2 (14 cases) had multi-level compression of spinal cord due to pre-existing cervical spine conditions such as ossification of posterior longitudinal ligament, cervical canal stenosis, and cervical spondylosis. Group 3 (7 cases) patients existed single-level compression of spinal cord by cervical disc herniations or spondylosis. We evaluated clinical results according to the Frankel classification, the American Spinal Injury Association (ASIA) scales and Japanese Orthopaedic Association (JOA) scores. Overall improvement of JOA and ASIA scores after treatment was 56.3 +/- 35.5% and 67.1 +/- 38.0%, respectively. Patients in Group 1 showed very good recovery after conservative treatment, with improvement of JOA and ASIA scores being 70.4 +/- 40.2% and 77.4 +/- 34.2%, respectively. The average interval between injury and operation was 4.3 +/- 4.4 months. The improvement of the surgically treated patients (Groups 2 and 3) in JOA and ASIA score was 48.2 +/- 30.7% and 61.2 +/- 39.6% respectively. We obtained good neurological recovery after operation, with significantly more improvement in Group 3 than in Group 2. No significant neurologic recovery had occurred preoperatively in these groups. In such patients operative intervention is essential for neurologic recovery.     

Mortality and neurologic morbidity after repair of traumatic aortic disruption

BACKGROUND: Traumatic disruption of the thoracic aorta frequently results in death before operative repair. The determinants of mortality after repair, however, are uncertain. In addition, intraoperative strategies for reducing the incidence of spinal cord injury remain controversial. METHODS: The records of 45 consecutive patients undergoing repair of traumatic disruption of the thoracic aorta at a single institution during a 9-year period were reviewed in a retrospective fashion. Patient age ranged from 15 to 81 years (mean age, 33.9 years). Twenty-two patients (49%) had multiple associated injuries, and 8 (18%) had isolated aortic injuries. Nine patients (20%) experienced preoperative hypotension (systolic blood pressure of less than 90 mm Hg). Repair was performed with partial bypass in 22 patients, a heparinized shunt in 2, and no distal perfusion (clamp and sew technique) in 21. RESULTS: Nine patient (20%) died after operation. Multivariate logistic regression analysis of preoperative and intraoperative variables identified advancing age and preoperative hypotension as independent predictors of operative death. The presence of associated injuries was not an independent predictor of operative death. All 4 patients with injuries proximal to the aortic isthmus died. Ten patients were excluded from analysis of spinal cord injury either because of preoperative neurologic deficit or because of death before postoperative evaluation. Six (17%) of the remaining 35 patients had development of paraplegia: 5 of the 15 patients having the clamp and sew technique, 1 of the 2 with a shunt, and 0 of the 18 patients with bypass (p < 0.05, clamp and sew versus bypass). In the clamp and sew group, patients in whom paraplegia developed had significantly longer aortic clamp times than those without neurologic injury (40.6 +/- 4.4 minutes versus 28.7 +/- 2.9 minutes, respectively; p < 0.05). CONCLUSIONS: Advancing age, preoperative hypotension, and perhaps injury location are important determinants of death after repair of traumatic disruption of the thoracic aorta. Adjunctive perfusion with partial bypass should be used during repair to reduce the incidence of spinal cord injury.     

Burst fractures of the second through fifth lumbar vertebrae. Clinical and radiographic results

Fifty-five patients who had sustained a burst fracture of the lumbar spine were followed for a mean of seventy-nine months (range, twenty-four to 192 months) after the injury. Thirty patients had been managed non-operatively with a short period of bed rest followed by protected mobilization. The remaining twenty-five patients had been managed operatively: eight, with posterior arthrodesis with long-segment hook-and-rod fixation; eight, with posterior arthrodesis with short-segment transpedicular fixation; six, with posterior arthrodesis and instrumentation followed by anterior decompression and arthrodesis; and three, with anterior decompression and arthrodesis. Thirty-six patients had been neurologically intact at the time of presentation and had remained so throughout the follow-up period. No neurological deterioration or symptoms of late spinal stenosis were seen. Isolated partial single-nerve-root deficits resolved regardless of the method of treatment. Patients who had had a complete single or a multiple-nerve-root paralysis seemed to have benefited from anterior decompression. Although the anatomical results as seen on the most recent radiographs were superior for the group that had been managed operatively with long posterior fixation or anterior and posterior arthrodesis, the most recent pain scores and the functional outcomes were similar for all treatment groups. At the latest follow-up evaluation, some loss of spinal alignment was noted in the patients who had been managed with short transpedicular fixation; the alignment at the most recent follow-up examination was comparable with that in the patients who had been managed non-operatively. For the patients who had had non-operative treatment, we were unable to predict the deformity at the time of follow-up on the basis of the initial diagnostic radiographs. The clinical outcome was not related to the deformity at the latest follow-up evaluation. On the basis of the results of our study, we recommend non-operative treatment for patients who do not have neurological dysfunction or who have an isolated partial nerve-root deficit at the time of presentation. For patients who have a multiple-nerve-root paralysis, anterior decompression is indicated.     

Surgical management for instability and paraplegia caused by spinal sarcoidosis. A case report

STUDY DESIGN: Report of a patient with paraplegia caused by vertebral sarcoidosis. OBJECTIVES: To report a rare case of vertebral sarcoidosis accompanied by progressive neurologic symptoms from the lower extremities, and to discuss the diagnostic and therapeutic approach to its management. SUMMARY OF BACKGROUND DATA: Vertebral sarcoidosis is a rare condition, and only a few case reports exist in the literature. A needle or open biopsy is required to establish the diagnosis. In most cases, treatment with steroids improves associated neurologic symptoms. Operative intervention is necessary in cases with progressive vertebral destruction, spinal instability, and impending or progressive neurologic deterioration. METHODS: Operative treatment by a two-stage anterior vertebrectomy and fusion followed by posterior stabilization was given to a patient with vertebral sarcoidosis and progressive neurologic deterioration of the lower extremities. RESULTS: After surgery, the patient had a complete neurologic recovery and satisfactory spinal fusion. CONCLUSIONS: In the absence of any spinal instability, neurologic symptoms associated with vertebral sarcoidosis respond satisfactorily to nonoperative treatment with steroids. Progressive neurologic deterioration or spinal instability caused by bone destruction requires operative intervention. Anterior vertebrectomy and fusion combined with posterior stabilization provided a satisfactory result for the patient in this report.     

Clinical consequences of spina bifida occulta

OBJECTIVE: To study data concerning the pathogenesis, frequency of occurrence, clinical manifestations and associated abnormalities of spina bifida occulta (SBO) and re-evaluate the clinical importance of the lesion. DATA SOURCES: International journal articles indexed through Medline, and specific related texts, the majority of which were published after 1989. Key indexing terms used were spina bifida occulta, tethered cord syndrome and spondylolysis. RESULTS: The reported frequency of occurrence of SBO varies widely, depending largely on the age groups included in a particular study. The most accurate estimate of occurrence rate is 17% of examined spines. There is a significant association of some cutaneous stigmata, most notably hypertrichosis, with midline posterior arch defects. An increasing amount of evidence links SBO with a number of specific anomalies and clinical syndromes, including intraspinal lipoma, tethered cord syndrome, genitourinary dysfunction, increased incidence of disc pathology, lumbar spondylolysis, foot deformities and syringomyelia. A questionable association exists with epilepsy. A supposed link between constipation and SBO is lacking sufficient data to support it. CONCLUSIONS: SBO may be associated with pathology and significant sequelae, although the majority of lesions pose no clinical threat. The predictive value for adverse sequelae in a particular lesion is difficult to assess; however, multilevel occurrence and more expansive involvement in a given segment seem to be associated with higher risk of sequela. The treatment for SBO with progressive neurologic deficit is surgical intervention; however, reversal of the deficit is unusual and a halting of neurologic deterioration is a more realistic goal. Early diagnosis of this lesion, before the age of 3 yr, is associated with better surgical outcomes.     

Neurosurgical treatment of trigeminal neuralgia. A comparative study of alcohol block, neurectomy and electrocoagulation

The objective was to assess the present condition of patients previously treated with neurosurgical procedures for trigeminal neuralgia (TN). Between 1976 and 1991, 383 patients were treated for TN at the Department of Neurosurgery, Hvidovre Hospital. The latest surgical intervention performed was radiofrequency coagulation (64%), neurectomy (18%), alcohol block (16%), trigeminal tractotomy (1%), and microvascular decompression (1%). Questionnaires were sent to 316 patients treated neurosurgically for trigeminal neuralgia during the 16 year period. After radiofrequency coagulation, neurectomy and alcohol block, 83, 51 and 42% respectively experienced a pain free postoperative period. At present 49, 17 and 18% were without pain and 33, 21 and 36% had less pain compared with the preoperative state. Sequelae were described in 65, 57 and 49% of the patients. The four most common sequelae were hypaesthesia, paraesthesia, eye complaints, and dysaesthesia. If relevant pharmacotherapy has been tried without benefit, radiofrequency coagulation may still be considered as a treatment of trigeminal neuralgia.     

Lumbar spinal stenosis in an elderly patient

BACKGROUND: The general population is aging, and lumbar stenosis is one of the more frequent conditions observed in an orthopedic or neurosurgical practice. METHODS: This case presentation is of an 86-year-old male who developed lumbar spinal stenosis with a progressive neurologic deficit that caused severe leg pain, affected bladder function, and affected gait. Relevant medical literature is reviewed. RESULTS: Bladder function and gait returned after spinal surgery, and this patient's pain was greatly reduced. A multidisciplinary team applied therapy after surgery. The medical literature does not concentrate solely upon patients older than 80, but a few are included in studies of younger patients. CONCLUSIONS: This case report illustrates that a patient over 80 can have a successful outcome with multidisciplinary medical coverage of medical, surgical, rehabilitative, social, and psychological areas. More studies need to be done of these patients.     

Tethered cord syndrome in occult spinal dysraphism: timing and outcome of surgical release

OBJECTIVE: To investigate the influence of neurosurgical intervention on the appearance of upper motor neuron (UMN) signs in newborns diagnosed with occult spinal dysraphism and tethered cord (TC) during the first month of life. METHODS: A prospective study (1990 to 1996) of 22 consecutive newborns with occult spinal dysraphism monitored for the appearance of UMN signs. Untethering was performed when neurologic or urodynamic investigation indicated the presence of UMN dysfunction. RESULTS: Of 22 patients, 10 remained free of UMN symptoms during follow-up (mean, 67+/-22 months). Untethering was performed in 12 of 22 patients because of the presence of UMN symptoms. In 7 of these 12 patients, there was a documented asymptomatic period of 13+/-11 months before the onset of UMN symptoms. Untethering at a mean age of 18+/-17 months restored normal neurologic and urinary function in all patients (mean postoperative follow-up, 25+/-16 months). Of the 12 children, 5 presented with UMN signs at birth. In these children, untethering was performed at a mean age of 9+/-5 months. In two of these five patients, UMN symptoms did not resolve after surgery, and ongoing conservative bladder treatment was required (mean follow-up, 37+/-14 months). In none of the 12 operated children did signs of retethering occur. CONCLUSIONS: A significant number (10/22) of children born with occult spinal dysraphism and TC did not develop UMN symptoms during follow-up; neurosurgical correction after the appearance of an UMN sign restored normal neurologic and urinary function in all children; and untethering in children presenting at birth with UMN symptoms resulted in poorer outcome.     

Long-term results of pedicle stabilized thoracolumbar fractures in relation to the neurological deficit

88 patients with thoracolumbar fractures and short-segment (mono or two segment) pedicle instrumentation from the years 1985-92 had a follow-up examination after an average time of 5.6 years. The 56 men and 32 women had an average age of 32.6 years at the time of injury, 24 patients primarily had a complete and 43 patients an incomplete paraplegia, 21 patients showed no neurological deficits. The operative decompression of the spinal cord and stabilization of the injured spine by short segment pedicle instrumentation led to a complete or partial remission of the neurological deficits in 93% of the patients with incomplete paraplegia. Operative stabilization allowed an early mobilization and rehabilitation of these patients. We found no tendency to an increased complication rate in patients with neurological deficits compared to patients without neurological deficits. Patients with initially incomplete paraplegia complained more often about pain than all the other patients. Despite intensive rehabilitation and retraining programs handicapped patients had obvious disadvantages regarding their further careers.     

Inhibition of neutrophil adhesion does not prevent ischemic spinal cord injury

Paraplegia may occur after transient aortic occlusion as a consequence of primary ischemia to the spinal cord or injury during the reperfusion period. In animal models of ischemia/reperfusion there is evidence that reperfusion injury may be modulated partially by neutrophils. The efficacy of the neutrophil adherence blocking murine monoclonal antibody (MAb 60.3) was assessed in spinal cord ischemia/reperfusion in rabbits. Spinal cord ischemia was accomplished by balloon catheter occlusion of the infrarenal aorta. Neurologic assessment was graded as normal, partial neurologic deficit, or complete paralysis. Electrophysiologic monitoring with somatosensory evoked potentials was used to determine the optimal length of time of occlusion. Animals were treated randomly with 2 mg/kg of intravenous Mab 60.3 (n = 8) or saline solution (n = 9) with the investigator unaware of treatment. Mean occlusion times were no different between groups (control, 32.7 +/- 3.6 minutes versus MAb, 32.4 +/- 6.0 minutes). Five (55%) saline-treated and four (50%) MAb 60.3-treated animals became paraplegic. Animals with initial paraparesis all progressed to flaccid paraplegia within 24 hours. We conclude that spinal cord injury after transient aortic occlusion is independent of the CD11/CD18 glycoprotein complex of the neutrophil. Injury in this setting may occur during ischemia and thus may not be dependent on neutrophils or reperfusion.     

Adding posterior lumbar interbody fusion to pedicle screw fixation and posterolateral fusion after decompression in spondylolytic spondylolisthesis

STUDY DESIGN: This is a retrospective study analyzing 76 patients treated by decompression, pedicle screw instrumentation, and fusion for spondylolytic spondyiolisthesis with symptomatic spinal stenosis. OBJECTIVES: To verify the advantages of adding posterior lumbar interbody fusion to the usual posterolateral fusion with pedicle screw instrumentation. SUMMARY OF BACKGROUND DATA: Stabilization after decompression of spondylolytic spondylolisthesis is difficult because of a lack of fusional bone bases, gap between the transverse process bases, and incompetent anterior disc support. Posterior lumbar interbody fusion offers anterior support, reduction, and a broad fusion base. METHODS: Forty patients were treated with posterolateral fusion, and 36 were treated with additional posterior lumbar interbody fusion. They were compared for union, reduction of the deformity, and clinical results. RESULTS: The patients were followed up for more than 2 years. Nonunion was observed in three patients who underwent posterolateral fusion (7.5%), and no cases of nonunion was found in patients who underwent posterior lumbar interbody fusion. Reduction of slippage was 28.3% in those who underwent posterolateral fusion and 41.6% in those who had posterior lumbar interbody fusion (P = 0.05). In the posterolateral fusion group, eight patients (20%) had recurrence of deformity, with loss of reduction more than 50%. Hardware failures occurred in two patients who had posterolateral fusion. There was no major neurologic complications in both groups. Both groups had satisfactory results in more than 90% of patients, with marked improvement of claudication. However, subjective improvement of back pain by Kirkaldy-Willis criteria revealed differences in the excellent results. An excellent result was reported by 45% in the posterolateral fusion group and by 75% in posterior lumbar interbody fusion group. CONCLUSIONS: The addition of posterior lumbar interbody fusion to posterolateral fusion after a complete decompression and pedicle screw fixation is a recommended procedure for the treatment of spondylolytic spondylolishesis with spinal stenosis.     

A difficult case involving a bradycardic patient

A seven-week-old, male chow chow-keeshond cross puppy was presented with acute paraplegia and episcleral hemorrhage. An X-linked, hereditary coagulopathy was suspected and confirmed by clotting factor analysis and necropsy findings of intraspinal hemorrhage. In young, male puppies with acute spinal pain and long-tract signs, intraspinal hematoma secondary to inherited X-linked coagulation factor deficiencies should be considered in the differential diagnosis.     

Surgical treatment of extensive skin necrosis secondary to purpura fulminans in a patient with meningococcal sepsis

This study reports an 8-year-old boy with chronic recurring thoracic pain. Magnetic resonance imaging of the spine revealed an intradural cyst at T1-T2. Despite severe compression of the spinal cord, there was no neurologic deficit. After minimally invasive cystectomy, the patient recovered completely. Histological examination established the diagnosis of a neurenteric cyst. The clinical, pathohistologic, and radiologic aspects are discussed, and the decisive role of magnetic resonance imaging in the diagnosis of intraspinal cyst is emphasized.     

Effect of negative middle-ear pressure on transient-evoked otoacoustic emissions

OBJECTIVE: To seek an optimal treatment plan from the results of treatment for metastatic disease of the spine in children. DESIGN: An 8-year retrospective study of children with metastatic disease of the spine. Imaging studies were reviewed and treatment modalities analysed. SETTING: The divisions of pediatric orthopedics and pediatric neurosurgery at the Children's Hospital of Eastern Ontario, Ottawa. PATIENTS: All children seen between April 1980 and December 1987 who had lesions metastatic to the spine by hematogenous or direct extension. There were 20 children (15 boys, 5 girls) with a mean age at the time of diagnosis of 9.5 years. Follow-up ranged from 2 weeks to 108 months. One child was lost to follow-up. INTERVENTIONS: Eleven children underwent laminectomy and decompression. Of the 14 neurologically compromised children, 5 received chemotherapy and radiotherapy and 9 received chemotherapy, radiotherapy and surgery. MAIN OUTCOME MEASURES: Type of metastatic lesion, vertebrae involved and response to therapy. RESULTS: Vertebrae involved with metastases were as follows: cervical (3), thoracic (5), lumbar (8) and multilevel (2). Meninges were involved in 2 cases. The most common causes of metastatic spinal involvement were neuroblastoma (4 cases) and astrocytoma (6 cases). Pathologic fractures occurred in 4 children and kyphoscoliosis in 4. Spinal cord paresis developed in 14 of the 20 children. Of the 6 children who survived from 48 to 108 months, 5 had tumours of neural origin, 4 being astrocytomas. Children with neuroblastoma or leukemic infiltration had a good initial response to chemotherapy. Five of the 6 surviving children had astrocytomas, and 5 were treated by surgical decompression. CONCLUSIONS: Metastatic disease of the spine in children secondary to astrocytoma should be treated aggressively, but from the experience gained from this study it is impossible to devise a rigid treatment plan for each type of metastatic tumour. The choice of chemotherapy, radiotherapy or surgery depends on the type of tumour, the age of the child and whether or not the spinal cord is compromised.     

Indirect spinal canal decompression in burst fractures treated with pedicle screw instrumentation

STUDY DESIGN: Prospective evaluation of spinal canal areas in 67 consecutive burst fractures between T12 and L2 treated by reduction and stabilization with a pedicle fixator. OBJECTIVES: Assessment of the efficacy of "indirect" spinal canal decompression in a large series of burst fractures. SUMMARY OF BACKGROUND DATA: Up to 50% of burst fractures cause neurologic impairment. Reduction and posterior instrumentation is the most common surgical treatment. This also reduces spinal canal encroachment by indirect decompression. No consensus exists as to the consistency and adequacy of such indirect decompression. METHODS: Spinal canal areas were measured on preoperative and postoperative computed tomography scans. The degree of encroachment was compared with clinical and radiographic variables for possible correlation. RESULTS: Spinal canal encroachment was more severe among patients with neurologic deficits than among the neurologically intact. Postoperatively, mean encroachment was reduced from 35% to 12% at T12, from 37% to 17% at L1, and from 52% to 35% at L2. Loss (and postoperative restoration) of anterior vertebral height correlated best with the degree of canal encroachment (and its reduction), especially in Denis Type A burst fractures. In Denis Type B fractures, canal compromise usually was less severe and fragment reduction better in patients older than 40 years of age than in younger patients. CONCLUSIONS: Indirect decompression in burst fractures averages about half of the preexisting encroachment. Results are usually better at T12 and L1 than at L2. Additional or secondary decompression is rarely indicated if these fractures are treated early and by experienced surgeons. Burst Type B fractures in patients older versus younger than 40 years of age differ in many respects.     

Glutamate neurotoxicity during spinal cord ischemia--development of a delayed-onset paraplegia model

The incidence and severity of spinal cord dysfunction are related to both the depth and duration of the resulting ischemic state. Evidence is accumulating that glutamate, a major neurotransmitter, has potent neurotoxic activity during ischemia. In our laboratory, it has been confirmed that exogenous glutamate has detrimental effects on spinal cord neurons during brief ischemia in vivo. We hypothesized that glutamate neurotoxicity is associated with delayed-neuronal dysfunction. Delayed-onset paraplegia is defined as a neurologic deficit which develops after initial recovery. Infrarenal aortic segments from 12 New Zealand white rabbits, were isolated for 5 minutes and perfused at a rate of 2 ml/min. Group I (n = 6) received normothermic saline (39 degrees C). Group II (n = 6) received normothermic L-glutamate (20 mM). Neurologic function was assessed at 6, 24, and 48 hours after surgery according to the modified Tarlov scale. After 48 hours, the rabbits were euthanized and their spinal cords were harvested for histologic examination. The neurologic function of all group I was fully intact, whereas three rabbits in group II showed acute paraplegia and the other three showed delayed-onset paraplegia. Histologic examination of spinal cords from rabbits in group I revealed no evidence of cord injury, whereas spinal cords from those in group II had evidence of moderate spinal cord injury with central gray matter and adjacent white matter necrosis and axonal swelling. These results indicate that dose-dependent glutamate neurotoxicity is associated with delayed neuronal dysfunction following ischemia in vivo. The severity of the ischemic event, i.e., extracellular glutamate overload, is suspected to be the etiology of delayed-onset paraplegia which, in turn, is thought to be the result of borderline ischemia. This model may allow a pharmacologic approach to the prevention of ischemic spinal cord injury.     

Strategies to prevent neurologic deficit based on motor-evoked potentials in type I and II thoracoabdominal aortic aneurysm repair

PURPOSE: Motor-evoked potentials (MEPs) were monitored during thoracoabdominal aortic aneurysm (TAAA) repair to assess spinal cord ischemia and evaluate the subsequent protective strategies to prevent neurologic deficit. METHODS: Between January 1996 and December 1997, 52 consecutive patients with type I (n = 24) and type II (n = 28) TAAA underwent surgery (mean patient age, 60 years; range, 21-78 years). The surgical protocol included left heart bypass, cerebrospinal fluid drainage, and monitoring transcranial myogenic MEPs. When spinal cord ischemia was detected, distal aortic pressure and mean arterial pressure were increased. By means of sequential crossclamping, MEPs were used to identify critical intercostal or lumbar arteries. RESULTS: Reproducible MEPs could be recorded in all patients, and spinal cord ischemia was detected within 2 minutes. During distal aortic perfusion, 14 patients (27%) showed rapid decrease in the amplitude of MEPs to less than 25% of baseline, indicating spinal cord ischemia, which could be corrected by increasing distal aortic pressure. The mean distal aortic pressure to maintain adequate cord perfusion was 66 mm Hg; however, it varied among individuals between 48 and 110 mm Hg. In 24 patients (46%), MEPs disappeared after segmental clamping and returned after reattachment of intercostal arteries. In 9 patients (17%), MEPs disappeared completely, but no intercostal arteries were found. After aortic endarterectomy, 6 or 8 mm Dacron grafts were anastomosed to intercostal arteries, and MEPs returned after reperfusion. Using this aggressive surgical approach based on MEPs, no early or late paraplegia occurred in this series. CONCLUSION: Monitoring of MEPs is an effective technique to assess spinal cord ischemia. Operative strategies based on MEPs prevented neurologic deficits in patients treated for type I and II TAAA.