Validation of the National Institute of Neurological Disorders and Stroke Spinal Cord Injury MRI Common Data Elements Instrument.

BACKGROUND AND PURPOSE: The National Institute of Neurological Disorders and Stroke common data elements initiative was created to provide a consistent method for recording and reporting observations related to neurologic diseases in clinical trials. The purpose of this study is to validate the subset of common data elements related to MR imaging evaluation of acute spinal cord injury. MATERIALS AND METHODS: Thirty-five cervical and thoracic MR imaging studies of patients with acute spinal cord injury were evaluated independently in 2 rounds by 5 expert reviewers. Intra- and interrater agreement were calculated for 17 distinct MR imaging observations related to spinal cord injury. These included ordinal, categoric, and continuous measures related to the length and location of spinal cord hemorrhage and edema as well as spinal canal and cord measurements. Level of agreement was calculated using the interclass correlation coefficient and kappa. RESULTS: The ordinal common data elements spinal cord injury elements for lesion center and rostral or caudal extent of edema or hemorrhage demonstrated agreement ranging from interclass correlation coefficient 0.68 to 0.99. Reproducibility ranged from 0.95 to 1.00. Moderate agreement was observed for absolute length of hemorrhage and edema (0.54 to 0.60) with good reproducibility (0.78 to 0.83). Agreement for the Brain and Spinal Injury Center score showed the lowest interrater agreement with an overall kappa of 0.27 (0.20, 0.34). For 7 of the 8 variables related to spinal cord injury, agreement improved between the first and second evaluation. Continuous diameter measures of the spinal cord and spinal canal using interclass correlation coefficient varied substantially (0.23 to 0.83). CONCLUSIONS: Agreement was more consistent for the ordinal measures of spinal cord injury than continuous measures. Good to excellent agreement on length and location of spinal cord hemorrhage and edema can be achieved with ordinal measures alone.

Congenital absence of the internal carotid artery in a patient with spinal cord injury: case report.

STUDY DESIGN: Case report. OBJECTIVE: To describe a rare case of congenital absence of the internal carotid artery (ICA) in the setting of acute spinal cord injury and review the existing literature. SETTING: Regional Spinal Cord Injury Center of the Delaware Valley, Philadelphia, PA, USA. CLINICAL PRESENTATION: We report on a 47-year-old male who presented as a T2 ASIA A spinal cord injury with a T2-T3 fracture dislocation injury after a 25-feet fall from a tree. Magnetic resonance angiography imaging of the neck carried out as per routine spinal trauma protocol suggested an acute traumatic injury to the carotid artery. Therefore, computed tomographic angiography imaging of the neck was performed, which revealed absence of the left ICA and a diminutive left carotid canal at the skull base, suggesting congenital absence. Follow-up magnetic resonance imaging of the brain to evaluate for acute infarct showed no diffusion restriction contributing to the evidence that this was a congenital anomaly and not traumatic occlusion of the artery. CONCLUSION: Congenital absence or hypoplasia of the ICA is a rare anomaly. It should be considered in the differential in patients who have absent or diminished carotid arteries on radiologic imaging in the setting of trauma.

Thromboprophylaxis in patients with acute spinal injuries: an evidence-based analysis.

BACKGROUND: The increased risk for venous thromboembolic events following spinal trauma is well established. The purpose of the present study was to examine the literature in order to determine the optimum thromboprophylaxis regimen for patients with acute spinal injuries with or without spinal cord injury. METHODS: EMBASE, MEDLINE, and Cochrane databases were searched from the earliest available date to April 2008 for clinical trials comparing different methods of thromboprophylaxis in adult patients following acute spinal injuries (with or without spinal cord injury). Outcome measures included the prevalences of deep-vein thrombosis and pulmonary embolism and treatment-related adverse events. RESULTS: The search yielded 489 studies, but only twenty-one of them fulfilled the inclusion criteria. The prevalence of deep-vein thrombosis was significantly lower in patients without spinal cord injury as compared with patients with spinal cord injury (odds ratio = 6.0; 95% confidence interval = 2.9 to 12.7). Patients with an acute spinal cord injury who were receiving oral anticoagulants had significantly fewer episodes of pulmonary embolism (odds ratio = 0.1; 95% confidence interval = 0.01 to 0.63) than those who were not receiving oral anticoagulants (either untreated controls or patients managed with low-molecular-weight heparin). The start of thromboprophylaxis within the first two weeks after the injury resulted in significantly fewer deep-vein-thrombosis events than delayed initiation did (odds ratio = 0.2; 95% confidence interval = 0.1 to 0.4). With regard to heparin-based pharmacoprophylaxis in patients with spinal trauma, low-molecular-weight heparin significantly reduced the rates of deep-vein thrombosis and bleeding episodes in comparison with the findings in patients who received unfractionated heparin, with odds ratios of 2.6 (95% confidence interval = 1.2 to 5.6) and 7.5 (95% confidence interval = 1.0 to 58.4) for deep-vein thrombosis and bleeding, respectively. CONCLUSIONS: The prevalence of deep-vein thrombosis following a spine injury is higher among patients who have a spinal cord injury than among those who do not have a spinal cord injury. Therefore, thromboprophylaxis in these patients should start as early as possible once it is deemed safe in terms of potential bleeding complications. Within this population, low-molecular-weight heparin is more effective for the prevention of deep-vein thrombosis, with fewer bleeding complications, than unfractionated heparin is. The use of vitamin K antagonists appeared to be effective for the prevention of pulmonary embolism.

Exophytic intramedullary meningioma of the cervical spinal cord.

Intramedullary spinal cord neoplasms are relatively uncommon. The most common intramedullary tumors are astrocytomas and ependymomas. Meningiomas can occur as an intradural tumor; however, they are typically in the extramedullary compartment. A 42-year-old male presented with progressive sensory loss in the upper extremities and lower extremity weakness. Pre-operative imaging suggested an intramedullary cervical lesion. To treat the progressive neurological abnormality, surgical resection was planned. At surgery, it was noted that the tumor originated in the cervical spinal cord and extended into the extramedullary region. Histology confirmed the lesion to be a meningioma. This meningioma variant has not previously been described. Spinal meningiomas may occur in locations other than intradural, extramedullary locations, and should be included in the differential diagnosis of intramedullary lesions. Intramedullary meningiomas can be successfully treated with surgery.

Prevention of carotid angioplasty-induced bradycardia and hypotension with temporary venous pacemakers.

OBJECTIVE: Carotid angioplasty with stent placement is becoming an established treatment modality for patients with high-risk carotid stenosis. Unlike carotid endarterectomy, angioplasty causes direct mechanical dilation of the stenotic carotid artery and bulb. Stimulation of the sinus baroreceptors induces a reflexive response that consists of increased parasympathetic discharge and inhibition of sympathetic tone, which results in bradycardia and subsequent cardiogenic hypotension. METHODS: At a single institution, the experience with 43 patients treated from November 1994 to January 2000 with 47 angioplasty and stent procedures for occlusive carotid artery disease was retrospectively reviewed. Prophylactic temporary venous pacemakers were used to prevent hypotension from possible angioplasty-induced bradycardia. Pacemakers were set to capture a heart rate decrease below 60 beats per minute. Variables analyzed included demographics, etiology of disease, side of the lesion, the presence of symptoms, history of coronary artery disease, percent stenosis, type of stent used, number of dilations, pressure of dilation, and angioplasty balloon diameter. RESULTS: Ten patients were excluded because pacemakers were not used during their angioplasty procedures, and these included three emergencies and a lesion that was unrelated anatomically to the carotid sinus (petrous carotid). The remaining 37 procedures were performed in 33 patients with a mean age of 67 years, and consisted of 17 men, 16 women, 20 right and 17 left-sided lesions. The pacemakers maintained a cardiac rhythm in 23 (62%) of the 37 procedures and in no case did the pacemaker fail to respond when activated. Recurrent (56%; 10 of 18), radiation-induced (78%; 7 of 9), and medically refractory carotid stenosis (67%; 6 of 9) required intraprocedural pacing. Two patients with recurrent stenosis became hypotensive despite the aid of the pacing device but were not symptomatic. Seventy-nine percent (15 of 19) of symptomatic lesions and 57% (8 of 14) of nonsymptomatic lesions required pacing, which was statistically significant (P = 0.049). No patient experienced an operative morbidity or mortality as a consequence of the temporary pacing devices. CONCLUSION: Angioplasty-induced bradycardia is a common condition, and it is more prevalent in radiation-induced stenosis and with symptomatic lesions. Temporary venous demand pacing is a safe procedure and may prevent life-threatening, baroreceptor-induced hypotension.

The cause of neurologic deterioration after acute cervical spinal cord injury.

STUDY DESIGN: A retrospective review was performed to identify patients at risk for secondary neurologic deterioration after complete cervical spinal cord injury. OBJECTIVE: To examine the causes of early neurologic deterioration in patients with complete spinal cord injury at a regional spinal cord injury center. SUMMARY OF BACKGROUND DATA: After complete spinal cord injury, neurologic deterioration occurs in a subgroup of patients. Despite anecdotal reports, no study has clearly identified the subgroups at highest risks. METHODS: One hundred eighty-two patients with complete spinal cord injury were identified among 1904 consecutive patients with acute spinal trauma evaluated from March 1993 through September 1999. Parameters analyzed included demographics, mechanism of injury, American Spinal Cord Injury Association (ASIA) level on admission and during hospital stay, onset of ascension, blood pressure, hemoglobin, febrile episode, heparin administration, and the timing of operation and traction. Radiographs of patients with ascending complete spinal cord injury were reviewed with attention to fracture type and neurologic and vascular injuries. RESULTS: Twelve of 186 patients with ASIA Grade A (6.0%) complete spinal cord injury had neurologic deterioration during the first 30 days after injury. No patients with penetrating injuries had deterioration. A significant association between death and ascension was observed. The onset of ascension of the injury could be categorized into three discrete temporal subsets. Early deterioration (less than 24 hours) was typically related to traction and immobilization. Delayed deterioration (between 24 hours and 7 days) was associated with sustained hypotension in patients with fracture dislocations. Late deterioration (more than 7 days) was observed in a patient with vertebral artery injuries. CONCLUSION: Delayed neurologic deterioration in complete spinal cord injury (ASIA A) is not rare. Specific causes were identified among discrete temporal subgroups. Management of complete spinal cord injury can be improved with recognition of these temporal patterns and earlier intervention.

Acute respiratory compromise associated with flexed cervical traction after C2 fractures.

STUDY DESIGN: Acute respiratory compromise is occasionally observed in a subgroup of patients with upper spinal injuries involving the C2 vertebrae. A retrospective review was performed to identify fracture types and risk factors for early respiratory deterioration following injury to the upper cervical spine. OBJECTIVES: To examine the frequency of respiratory complications encountered following traction manipulation of specific upper cervical spinal injuries involving the C2 vertebrae. SUMMARY OF BACKGROUND DATA: Major complications related to cervical skeletal traction are uncommon. Respiratory compromise with occasional mortality has been observed. Risk factors for acute respiratory failure are unknown. METHODS: The medical records of 166 consecutive patients with fractures of the C2 vertebrae admitted between January 1994 and July 1998 to a regional spinal cord injury center were examined. Demographic data, injury subtype, fracture displacement, respiratory status, treatment method, and outcome at discharge were examined. Patients with comorbidities compromising respiratory function were excluded. RESULTS: One hundred fifty-five patients met the inclusion criteria of this study. Sixty-one patients had Type II odontoid fractures of which 53 were displaced (32 posteriorly and 21 anteriorly). In addition, there were 21 patients with Type III odontoid fractures, 33 with axis C2 body fractures, 32 with Hangman's fractures, and eight patients with an os odontoideum. Thirteen of 32 patients with posteriorly displaced odontoid fractures experienced acute respiratory compromise following reduction with cervical skeletal traction and immobilization, while only three of the remaining 123 patients had respiratory difficulties. Respiratory distress as a consequence of cervical spine fractures resulted in three deaths. Two of these patients had posteriorly displaced Type II odontoid fractures whose airway could not be emergently intubated. CONCLUSION: Frequent respiratory deterioration (40% of patients) during acute management of posteriorly displaced Type II odontoid fractures after reduction was observed. Physicians must be aware that cervical flexion in the treatment of posteriorly displaced odontoid fractures may significantly increase the risk of airway obstruction due to the presence of acute retropharyngeal swelling. This may be avoided with elective nasotracheal intubation in this upper cervical spine fracture subtype.

Closed management of displaced Type II odontoid fractures: more frequent respiratory compromise with posteriorly displaced fractures.

OBJECT: Acute respiratory failure has been observed in patients after external immobilization for displaced odontoid fractures. The authors studied the frequency of respiratory deterioration in the acute management of displaced Type II odontoid fractures to identify patients at risk for respiratory failure. METHODS: The authors conducted a retrospective review of a consecutive series of 89 patients with odontoid fractures who were treated over a 5-year period to identify 53 patients with displaced Type II odontoid fractures. Patient demographics, degree of displacement, respiratory status, treatment method, and outcome were examined. Of the 32 patients with posteriorly displaced fractures, 13 experienced acute respiratory compromise, whereas only one of 21 patients with anteriorly displaced fractures had respiratory difficulties (p = 0.0032). The average posterior displacement was 6.9 mm. All 13 were initially managed using flexion traction for reduction of these fractures. Two of these patients died because of failure to emergently secure an airway during closed treatment of the fracture. CONCLUSIONS: Frequent respiratory deterioration during acute closed reduction of posteriorly displaced Type II odontoid fractures was observed, whereas respiratory failure in patients with anteriorly displaced fractures was rare. The use of the flexed cervical position in the setting of retropharyngeal edema rather than the direction of the displacement may substantially increase the risk of respiratory failure. This may prompt early elective nasotracheal intubation during closed reduction of posteriorly displaced Type II odontoid fractures that require a flexed posture.

Epidemiology of spinal cord injury after acute odontoid fractures.

OBJECT: Cervical spinal cord injury (SCI) after odontoid fracture is unusual. To identify predisposing factors, the authors evaluated a consecutive series of patients who sustained SCI from odontoid fractures. METHODS: A consecutive series of 5096 admissions to the Delaware Valley Regional Spinal Cord Injury Center were reviewed, and 126 patients with neurological impairment at the C1-3 levels were identified. Seventeen patients had acute closed odontoid fractures with neurological deficit. Various parameters including demographics, mechanisms of injury, associated injuries, fracture types/displacements, and radiographic cervical canal dimensions were compared between "complete" and "incomplete" spinal cord injured-patients as well as with neurologically intact patients who had suffered odontoid fractures. There were similar demographics, mechanisms of injury, associated injuries, fracture type/displacement, and canal dimensions in patients with complete and incomplete SCIs. However, only patients with complete injury were ventilator dependent. In comparison with patients with intact spinal cords, spinal cord-injured patients were more commonly males (p = 0.011) who had sustained higher velocity injuries (p = 0.027). The computerized tomography scans of 11 of 17 neurologically impaired patients were compared with those of a random sample of 11 patients with intact spinal cords. Although the anteroposterior diameter (p = 0.028) and cross-sectional area (p = 0.0004) of the cervical spinal canal at the C-2 level were smaller in impaired patients, the displacement of the fragment was not different. CONCLUSIONS: Odontoid fractures are an infrequent cause of SCI. Patients with these injuries typically are males who have smaller spinal canals and have sustained high velocity injuries.

Efficacy of anterior odontoid screw fixation in elderly patients with Type II odontoid fractures.

OBJECT: Type II odontoid fractures are the most common trauma-related dens fracture. Although Type III odontoid fractures have a high union rate when external immobilization is applied, Type II fractures are associated with high rates of nonunion, particularly in elderly patients and those with posteriorly displaced fractures or fractures displaced by more than 6 mm. Because elderly patients may not also tolerate external immobilization in a halo vest, alternative techniques should be explored to identify a method for managing these higher-risk patients. In this study the authors examine the efficacy of anterior odontoid screw fixation in a high-risk group of 10 elderly patients (> 65 years of age) treated for Type II odontoid fractures. METHODS: A retrospective review of all patients with Type II odontoid fractures treated at two institutions between September 1997 and March 2000 was performed. Demographic data, neurological examination, fracture type and degree of displacement, treatment method, and outcome data were examined at discharge. Ten patients older than 65 years who had sustained a trauma-related odontoid fracture and had undergone an anterior odontoid screw placement procedure were retrospectively reviewed. Fracture displacement (mean 6.6 mm) was observed in all but one patient, and in seven there were posteriorly displaced fractures. Seven were successfully treated with anterior screw fixation and external orthosis alone; in one patient in whom poor intraoperative screw purchase had been observed, the fracture healed after undergoing halo vest therapy. Only one patient was shown to develop a nonunion requiring a subsequent posterior fusion procedure. CONCLUSIONS: Odontoid screw fixation can be safely performed in elderly patients, and frequent bone union is demonstrated. However, osteopenia may preclude adequate screw fixation in some patients.

Use of an osteoconductive agent (Norian) in anterior surgical management of odontoid fractures. Technical note.

Odontoid fractures can be successfully treated with anterior screw fixation. Odontoid fractures commonly occur in older patients who may have significant osteopenia. The authors examined the use of a bone substitute to overcome limitations encountered during a procedure in which anterior odontoid screw fixation is performed. Two elderly patients with displaced, reducible acute odontoid fractures underwent anterior odontoid screw fixation. The intraoperative failure of the anterior vertebral cortex from osteopenic bone and failure to achieve complete contact between the dens and axis were encountered. The defects were supplemented by using the osteoconductive agent Norian. Outcome was evaluated to determine the utility of this method. Occasional intraoperative failure of anterior odontoid screw fixation may be encountered. Supplementation of bone defects with this osteoconductive agent may facilitate successful bone union in selected patients.

Humoral hypercalcaemia in renal carcinoma due to parathyroid hormone related protein.

Parathyroid hormone related protein (PTHRP) has been implicated in humoral hypercalcaemia of malignancy (HHM). We describe a patient with a renal carcinoma and hypercalcaemia, and for the first time have demonstrated a 4-fold PTHRP concentration gradient across a renal tumour bed. This provides further strong evidence that the primary tumour was the source of the PTHRP. The PTHRP 1-86 content of the tumour tissue was 4.8 ng/g, similar to that previously found in tumours associated with HHM. In PTHRP-secreting tumours, PTHRP may be a useful oncological marker after surgical resection.

Performance and clinical utility of a commercially available 'C-terminal' PTH assay.

The performance and clinical utility of a 'C-terminal' parathyroid hormone (PTH) radioimmunoassay (Dac-Cel, Wellcome Diagnostics) is described. Parathyroid hormone, as measured by the Dac-Cel method, is stable in whole blood samples for at least 24 h. 84% of patients with hypercalcaemia due to primary hyperparathyroidism have values above the upper limit seen in normocalcaemic subjects (0.5 micrograms/L), with detectable serum PTH demonstrable in the remaining 16%. In patients with hypocalcaemia due to hypoparathyroidism serum PTH was undetectable in 73% and 'inappropriately' low in the remainder. In 50% of patients with malignancy-associated hypercalcaemia serum PTH was undetectable, but was above 0.5 micrograms/L in 13%. Increased PTH concentrations were invariably found in patients with renal failure. The Dac-Cel method is a reliable and robust technique for measurement of PTH and in conjunction with determination of calcium facilitates the diagnosis of primary parathyroid disorders. Caution is required in the interpretation of PTH measurements in patients with renal failure; the significance of detectable PTH in some patients with malignancy-associated hypercalcaemia is not clear.

Immunoradiometric assay of thyrotropin as a "first-line" thyroid-function test in the routine laboratory.

We compared the utility of a sensitive immunoradiometric assay for serum thyrotropin as a "first-line" thyroid-function test with a strategy based on first measuring total thyroxin in serum. The immunoradiometric assay appears to distinguish primary hypothyroidism and hyperthyroidism from euthyroidism in "new" patients. The role of this test in monitoring antithyroid treatment or thyroxin-replacement therapy is not yet established, there being particular difficulty in interpreting low thyrotropin concentrations in such patients. Nevertheless, because a normal thyrotropin concentration in most, if not all, situations signifies the euthyroid state, thyrotropin determination by immunoradiometric assay merits consideration as an initial test by laboratories performing thyroid-function tests.

Circannual and within-individual variation of thyroid function tests in normal subjects.

Blood was taken from normal subjects at monthly intervals over a period of one year for subsequent determination of serum thyroid hormone concentrations. Thyroid-stimulating hormone (TSH) responses to TSH-releasing hormone were performed at 3-monthly intervals. This study provided data on within-individual variation and on seasonally-related changes of these thyroid function tests. The results showed that, within an individual, thyroid hormone concentrations are maintained within narrow limits. For both thyroxine and triiodothyronine the component contribution of within-individual variation to the population-based variation (the latter also termed the 'reference interval', or colloquially the 'normal range') was small. This high degree of individuality implies that rigorous comparison of thyroid hormone results against a population-based 'normal range' can be potentially misleading. Despite the limited within-individual variation, seasonally-related changes in thyroid hormone concentrations were apparent, with higher thyroxine and triiodothyronine values seen in winter months. A tendency to a greater TSH response to TSH-releasing hormone was also noted at this time. Conceivably these changes could reflect a centrally-mediated response of the hypothalamic-pituitary-thyroid axis to environmental temperature.

The effects of ranitidine on pituitary-thyroid function.

Although several studies have examined the effects of cimetidine on pituitary-thyroid function, few have investigated ranitidine in this respect. We found no changes in thyroid-stimulating-hormone (TSH) or prolactin responses to TSH-releasing-hormone (TRH) in 10 patients with peptic ulcer disease given oral ranitidine. Serum total and free thyroxine (TT4 and FT4) concentrations declined slightly, whereas total and free triiodothyronine (TT3 and FT3) increased slightly following ranitidine. None of these changes achieved statistical significance. Both the ratio of TT4/TT3 and FT4/FT3, however, declined (P less than 0.05) following ranitidine. Thus ranitidine may have a minor influence on peripheral deiodination of thyroxine but has little effect on hormone production from the thyroid gland. The diagnostic value of biochemical tests of thyroid function is not seriously compromised in patients receiving ranitidine.

Myoglobin concentration, creatine kinase activity, and creatine kinase B subunit concentrations in serum during thyroid disease.

Changes in values for myoglobin, total creatine kinase (EC 2.7.3.2), and creatine kinase B-subunit in the serum of patients with thyroid disease are compared with values for these during the 24-h after myocardial infarction. Concentrations of all three of these muscle-derived proteins were significantly higher than normal in patients with primary hypothyroidism, and declined with treatment. Values for total creatine kinase activity were below-normal in hyperthyroid patients, but increased after treatment. Values for total creatine kinase and, to a lesser extent, myoglobin in hypothyroidism extend into the range of values observed after myocardial infarction. The mechanism of the changes in these analytes in hypothyroidism may be related to increased leakage from skeletal-muscle cells or diminished clearance from the circulation, or both.