Biomedical subjects
Publications and source records attributed to M N Hadley.
Magnetic resonance images enhanced with the paramagnetic contrast agent gadolinium-DTPA accurately differentiated a recurrent intramedullary spinal cord ependymoma from surrounding postoperative and postirradiation spinal cord tissue changes, thereby facilitating total excision of the lesion. The illustrative case and the merits of enhanced magnetic resonance imaging are presented.
The clinical and pathological effects of nimodipine on cerebral infarction were investigated in 12 male baboons. In randomized/blind trials, six animals given intravenous nimodipine (2 micrograms/kg/min load, 1 microgram/kg/min maintenance) for 96 hours starting 50 minutes before 6-hour double-clip occlusion of the middle cerebral artery were compared to 6 control animals. Standardized neurological examinations were performed by examiners blinded to the animals' therapy on Day 7 and Day 14 after stroke. On Day 14 the animals were killed. The brains were studied pathologically, and the relative areas of infarction were quantified. Intracranial pressure was lower in nimodipine-treated animals; however, the range of intracranial pressure values in each group was broad. Two control animals with high intracranial pressure died. There were no deaths among the nimodipine-treated animals. The neurological scores on Days 7 (P less than or equal to 0.01) and 14 (P less than or equal to 0.05) were significantly different between the two groups. The nimodipine-treated animals had less clinical evidence of infarction compared to controls. Nimodipine-treated animals tended to have smaller areas of infarction; however, the difference between the two groups was not statistically significant. The infusion of nimodipine in the treatment of focal cerebral ischemia is safe and does not appear to aggravate the extent of infarction or to exacerbate intracranial hypertension. The clinical neurological evaluations indicate that nimodipine may improve or preserve neurological outcome after stroke.
The cases of 13 infants (median age, 3 months) who sustained nonaccidental trauma were reviewed. All presented with profound neurological impairment, seizures, retinal hemorrhages, and intracranial subarachnoid and/or subdural hemorrhages. Of 8 infants who died, autopsy was performed on 6. No patient had a skull fracture, and only one had an extracalvarial contusion. Five of the 6 patients on whom autopsy was performed had injuries at the cervicomedullary junction consisting of sub- or epidural hematomas of the cervical spinal cord with proximal spinal cord contusions. The authors conclude that direct cranial trauma is not an essential element of the injury mechanism in young patients who sustain severe whiplash-shake injuries. In addition to the classic injuries reported to occur with the shaken-baby syndrome, hemorrhages and contusions of the high cervical spinal cord may contribute to morbidity and mortality.
Combination atlas-axis fractures occur relatively frequently and have a higher incidence of neurological morbidity than isolated C-1 or isolated C-2 injuries. Patients with combination C1-2 fracture-subluxation injuries should be studied with thin-section computerized tomography. Appropriate treatment is determined by the type of axis fracture present and includes surgical and nonsurgical strategies. An experience with 25 patients with combination C1-2 fractures is presented, and management and follow-up guidelines are reviewed.
The transoral-transclival surgical approach is the most direct operative approach to pathology ventral to the brain stem and superior spinal cord. In selected patients, this approach is efficacious in the treatment of extradural compressive lesions from the cervicomedullary junction to the C-4 vertebra. The authors have used the transoral surgical approach in treating 53 patients with lesions compressing the ventral extradural brain stem or the cervical cord. The evaluation, management, and long-term outcome of these patients are described (median follow-up time 24 months). The operative morbidity rate in this series was 6%, and the operative mortality rate was zero. The authors review specific features of the transoral procedure, including methods of retraction, microsurgical techniques, and adjunctive measures to avoid cerebrospinal fluid fistulae, that contributed to these good results.
Eighteen percent of acute cervical spine fractures involve the C-2 vertebra. The odontoid Type II fracture is the most common axis fracture and it is also the most difficult to treat. The degree of odontoid dislocation has been identified as the single most important fracture feature that helps separate those patients who have a high likelihood of healing with nonoperative therapy from those who are likely to fail nonoperative therapy and should be offered early surgical stabilization. The difference is statistically significant (p less than 0.001, x2 = 30.20). The present series includes 229 patients with acute axis fractures. Follow-up data were available in 92% of these patients, for a median duration of 4 years 9 months. Treatment guidelines and results are offered for each subtype of axis fracture based on this experience.
Cerebral ischemia is a complex injury process that occurs when the nutrient blood supply to cerebral structures is reduced below critical levels. The causes of cerebral ischemia are protean, but the underlying pathophysiologic mechanism that leads to injury is a mismatch between the supply of nutrients to a given cell (or population of cells) and the demand of the cell(s) for those essential nutrients. Extensive research is ongoing in our attempt to find a treatment strategy and/or pharmacologic agent that might protect cerebral structures when exposed to ischemia. To date, few strategies or agents have proven themselves truly "protective." In this communication, the complexities of the cerebral ischemia injury process will be reviewed, the principles of cerebral protection (both practical and theoretical) will be outlined, and the merits of barbiturate anesthesia with regard to planned temporary cerebral ischemia will be discussed.
We studied 24 patients with histologically verified cerebral cavernous malformations, reviewing the familial occurrence and presenting signs, symptoms, and radiographic features of the disorder. Eleven patients had no evidence of a heritable trait and had negative family histories. Thirteen patients were members of six unrelated Mexican-American families. Sixty-four first-degree and second-degree relatives were examined, and family pedigrees were established. Most relatives (83 percent) were asymptomatic; 11 percent had seizures. Magnetic resonance imaging was performed in 16 relatives (5 of whom were asymptomatic). Fourteen of the 16 studies revealed cavernous malformations; 11 studies identified multiple lesions. As compared with computerized tomography and angiography, magnetic resonance imaging was far more accurate in detecting cavernous malformations. We conclude that cavernous malformations are more prevalent than previously reported, and that a familial form of the disorder exists that is more common than expected, with a high incidence of multiple lesions and an increased frequency of occurrence among Mexican-American families. Magnetic resonance imaging is the radiographic technique of choice for the identification and follow-up of these lesions.
Fractures of the first cervical vertebra (C1) represent approximately 7% of all acute cervical spine fractures. Frequently, the atlas will be fractured in combination with the axis (44% of cases). Treatment of isolated C1 fractures should be governed by the rules of Spence. The treatment of combination C1-C2 fractures is dictated by the type and severity of the C2 fracture. Experience with 57 cases of acute traumatic atlas fractures are reviewed. The long-term outcome from an atlas fracture is good (median follow-up, 40 months).
The transoral surgical approach is the most direct operative approach to pathology ventral to the brain stem and superior spinal cord. This approach is useful in the treatment of extradural compressive cervicomedullary lesions in selected patients. Twenty-nine patients with ventral extradural brain stem or cervical cord compressive lesions who were treated via the transoral surgical approach are presented. Their evaluation, treatment, and long-term outcome will be reviewed (median follow-up, 24 months). Specific features of the transoral procedure, including intraoperative monitoring, methods of retraction, and microsurgical techniques that contributed to minimal operative morbidity (3%) and zero operative mortality, will be discussed.
A new subtype of axis fracture, thought to be a variant of the Type II odontoid fracture, is described. High resolution, thin section computed tomography can assist in the identification of comminuted fractures at the base of the dens with associated free fracture fragments. Because these injuries are markedly unstable and cannot be suitably realigned and reduced by external means, early surgical therapy should be considered.
A watertight dural closure is difficult to achieve after transoral-transclival operation for ventral intradural lesions at the craniocervical junction. These procedures have a high morbidity and mortality from cerebrospinal fluid (CSF) fistula, meningitis, and abscess. We used a canine model to test three different techniques of dural closure after transoral intradural operation: primary suture closure, laser patch weld, and fibrin glue patch closures. The primary suture closure technique was inadequate. All eight leaked CSF at the time of operation, and five had radiographic leaks and were incompetent at autopsy. All seven of the laser closures leaked CSF at operation, yet only one was incompetent at autopsy. The fibrin glue technique was superior and provided a solid seal at operation, even with repeated Valsalva maneuvers to 40 mm Hg. The immediate and persistent seal at operation is clinically significant because it may prevent CSF leak, meningitis, and abscess formation in human patients after transoral surgery. Fibrin glue is excellent for repairing complex dural defects and merits evaluation in clinical trials.
Fractures of the 1st cervical vertebra (C1) represent 7% of all acute cervical spine fractures. Isolated atlas fractures are most commonly bilateral or multiple fractures through the ring of C1. Frequently (44% of cases), the atlas will be fractured in combination with the axis. Treatment of isolated C1 fractures should be governed by the rules of Spence. The treatment of combination C1-C2 fractures is dictated by the type and severity of the C2 fracture. Experience with 57 cases of acute atlas fractures is reviewed. Nonoperative external immobilization was used in 53 patients (with 1 failure), and early surgical wiring and fusion were performed in 4 patients. The long term outcome from an atlas fracture is good (median follow-up, 40 months).
A review of 122 pediatric cases of vertebral column and spinal cord injuries is presented. These relatively uncommon injuries can be characterized by four distinct injury patterns: fracture only, fracture with subluxation, subluxation only, and spinal cord injury without radiographic abnormality. The immature pediatric spine has several anatomical and biomechanical features that distinguish it from the mature adolescent spine and, accordingly, the frequency of the injury type, the level of spine injury, and the incidence of neurological compromise were found to vary with the age of the patient. Follow-up data were obtained in 93% of the cases (median duration 44 months). No patient was made worse by treatment, 89% of the patients with incomplete myelopathy on admission were improved on their last examination, and 20% of the patients with a complete myelopathy had evidence of significant recovery of function. The authors conclude that the outcome after pediatric spinal trauma is good.
Complete circulatory arrest, deep hypothermia, and barbiturate cerebral protection are efficacious adjuncts in the surgical treatment of selected giant intracranial aneurysms. These techniques were utilized in seven patients, one with a large and six with giant basilar artery aneurysms; four had excellent results, one had a good result, one had a fair outcome, and one died. The rationale for the use of complete cardiac arrest with extracorporeal circulation, hypothermia, and barbiturate cerebral protection is outlined. The surgical and anesthetic considerations are reviewed. The perioperative morbidity and long-term results support the use of these techniques in selected patients with complex intracranial vascular lesions.
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Nocardia asteroides is an uncommon human pathogen typically encountered in immunocompromised patients. Primary central nervous system (CNS) nocardiosis is rare and usually manifests as cerebritis or abscesses. The case of a young woman who presented with CNS Nocardia abscesses complicated by an infective middle cerebral artery aneurysm is reported. Treatment, which included abscess aspiration, aneurysm excision, and end-to-end extracranial to intracranial bypass and prolonged antibiotic therapy, resulted in an excellent outcome. This case and the management of CNS nocardiosis are reviewed.
The halo brace has presented the neuroscience nurse with a new challenge in the care of victims of cervical spine trauma. In a review of 147 patients admitted to the Barrow Neurological Institute (BNI) with cervical fractures and/or instability during an 18-month period, the halo brace was an integral part of the treatment regimen in 71% of the cases. A vigorous nursing/respiratory care treatment protocol has been generated for the halo brace patient, focusing primarily on individuals who are quadriplegic, ventilator dependent, or elderly. This protocol and appropriate nursing interventions will be presented. The halo brace treatment plan has been effective in promoting early patient mobilization and reducing sensory deprivation and common pulmonary, vascular, gastrointestinal, and skin complications, thus shortening the acute hospital stay and allowing earlier admission to the rehabilitation setting.