Examining lactate in severe TBI using proton magnetic resonance spectroscopy.

PRIMARY OBJECTIVE: Clinical management of acute traumatic brain injury (TBI) has emphasized identification of secondary mechanisms of pathophysiology. An important objective in this study is to use proton magnetic resonance spectroscopy (pMRS) to examine early metabolic disturbance due to TBI. RESEARCH DESIGN: The current design is a case study with repeated measures. METHOD AND PROCEDURE: Proton magnetic resonance imaging was used to examine neurometabolism in this case of very severe brain trauma at 9 and 23 days post-injury. MRI was performed on a clinical 1.5 Tesla scanner. MAIN OUTCOMES AND RESULTS: These data also reveal that pMRS methods can detect lactate elevations in an adult surviving severe head trauma and are sensitive to changes in basic neurometabolism during the first month of recovery. CONCLUSIONS: The current case study demonstrates the sensitivity of pMRS in detecting metabolic alterations during the acute recovery period. The case study reveals that lactate elevations may be apparent for weeks after severe neurotrauma. Further work in this area should endeavour to determine the ideal time periods for pMRS examination in severe TBI as well as the ideal locations of data acquisition (e.g. adjacent or distal to lesion sites).

Positioning of vagal nerve stimulators: technical note.

BACKGROUND: Vagal nerve stimulation has become an important treatment for patients with intractable seizure disorders. Many of these patients will require magnetic resonance imaging (MRIs) of the brain after the stimulator has been implanted to monitor underlying neurologic conditions. Functional MRI (fMRI) is also being used in the evaluation of epilepsy. With the current recommended implant techniques the magnetic field of the MRI will deactivate the pulse generator while the patient is in the supine position for the scan. A simple change in positioning of the pulse generator will help to avoid deactivating the device during an MRI. This will avoid exposing the patient to lengthy time periods with a deactivated stimulator and also allow for the performance of fMRIs and any other MRI scans needed to monitor underlying neurologic conditions. METHODS: A working model of the NeuroCybernetic Prosthesis (NCP) pulse generator was assessed with an oscilloscope and LED light connected to it that related activation of the generator while in the MRI. This simulation was performed with the device alone, in multiple positions. Then patients with implanted devices who could personally confirm the activation of their stimulators were also studied. RESULTS: A pulse generator placed with the electrode inputs parallel to the long axis of the body was not deactivated by the magnetic field of the MRI when the patient was in the supine position. CONCLUSION: Changing the implant position of a vagal nerve stimulator pulse generator will help to prevent deactivation of the device while in the MRI, allowing for the performance of fMRIs while not exposing the patient to lengthy time periods with a deactivated vagal nerve stimulator.

Sensory impairment: a feature of chronic venous insufficiency.

OBJECTIVE: Clinical and microscopic evidence suggests the existence of sensory neuropathy in patients with severe chronic venous insufficiency (CVI). A clinical evaluation was conducted to determine whether a sensory neuropathy was present and, if so, to determine its extent and distribution. METHODS: The study was performed in a university-affiliated Veterans Affairs Medical Center. Twenty-three limbs were studied in 14 male veterans with mild or moderate CVI. The exclusions included diabetes, previous ipsilateral extremity surgery, or other diseases associated with neuropathy. Sensory thresholds in the limbs with CEAP class 2 disease (n = 11) were compared with the thresholds in the limbs with CEAP class 5 disease (n = 12) at nine different sites on the foot, ankle, calf, thigh, and palm. Thenar and hypothenar thresholds were measured as internal controls. Thresholds were determined by a pressure aesthesiometer consisting of 20 graduated filaments that ranged from 1.65 to 6.65 (log(10)mg)(10) of pressure. A complete, sensory motor assessment of the limb was performed by an experienced neurosurgeon who specialized in peripheral nerve evaluation. The clinical variables assessed were deep tendon reflexes, vibration, proprioception, and light touch. Venous reflux was determined with duplex ultrasound scanning and air plethysmography. RESULTS: Sensory thresholds at the most common site of venous ulceration-just proximal to the medial malleolus--were significantly (P <.05) different between mild (class 2) and severe (class 5) CVI. Sensory abnormalities coincided with the extent of trophic changes and did not reflect specific dermatomal or cutaneous nerve distributions. In addition to light touch or pinprick, vibration sense and deep tendon reflexes were also significantly worse in those with severe CVI. CONCLUSION: Sensory neuropathy is a feature of severe CVI, and its distribution is coincident with trophic changes. Because this is often unappreciated by the patient, it probably contributes to the propensity for deterioration from minor trauma.

Propofol in the treatment of moderate and severe head injury: a randomized, prospective double-blinded pilot trial.

OBJECT: Sedation regimens for head-injured patients are quite variable. The short-acting sedative-anesthetic agent propofol is being increasingly used in such patients, yet little is known regarding its safety and efficacy. In this multicenter double-blind trial, a titratable infusion of 2% propofol accompanied by low-dose morphine for analgesia was compared with a regimen of morphine sulfate in intubated head-injured patients. In both groups, other standard measures of controlling intracranial pressure (ICP) were also used. METHODS: Forty-two patients from 11 centers were evaluated to assess both the safety and efficacy of propofol: 23 patients in the propofol group (mean time of propofol usage 95+/-87 hours) and 19 patients in the morphine group (mean time of morphine usage 70+/-54 hours). There was a higher incidence of poor prognostic indicators in the propofol group than in the morphine group: patient age older than 55 years (30.4% compared with 10.5%, p < 0.05), initial Glasgow Coma Scale scores of 3 to 5 (39.1% compared with 15.8%, p < 0.05), compressed or absent cisterns on initial computerized tomography scanning (78.3% compared with 57.9%, p < 0.05), early hypotension and/or hypoxia (26.1% compared with 10.5%, p = 0.07). During treatment there was a trend toward greater use of vasopressors in the propofol group. However, the mean daily ICP and cerebral perfusion pressure were generally similar between groups and, on therapy Day 3, ICP was lower in the propofol group compared with the morphine group (p < 0.05). Additionally, there was less use of neuromuscular blocking agents, benzodiazepines, pentobarbital, and cerebrospinal fluid drainage in the propofol group (p < 0.05). At 6 months postinjury, a favorable outcome (good recovery or moderate disability) was observed in 52.1% of patients receiving propofol and in 47.4% receiving morphine; the mortality rates were 17.4% and 21.1%, respectively. Patients who received the highest doses of propofol for the longest duration tended to have the best outcomes. There were no significant differences between groups in terms of adverse events. CONCLUSIONS: Despite a higher incidence of poor prognostic indicators in the propofol group, ICP therapy was less intensive, ICP was lower on therapy Day 3, and long-term outcome was similar to that of the morphine group. These results suggest that a propofol-based sedation and an ICP control regimen is a safe, acceptable, and, possibly, desirable alternative to an opiate-based sedation regimen in intubated head-injured patients.

Cervical myelopathy due to migration of Torkildsen's shunt: case report.

BACKGROUND: Ventriculocisternal (Torkildsen's) shunts were used often in the past for the treatment of patients with obstructive hydrocephalus. Cisternal shunts may still be indicated in the management of syringomyelia. CASE DESCRIPTION: Presented is a case of a patient developing cervical myelopathy due to migration of a Torkildsen's shunt placed 30 years before. Initially thought to have a malfunctioning shunt, he then underwent removal of the catheter, which was demonstrated on magnetic resonance imaging (MRI) to be compressing the cervicomedullary junction. The patient improved slightly after removal of the catheter. CONCLUSIONS: Patients with cisternal shunts in whom a cervical myelopathy develops should be evaluated with MRI to rule out upper spinal cord compression caused by a migrated catheter.

Failure of hydroxyapatite cement to set in repair of a cranial defect: case report.

OBJECTIVE AND IMPORTANCE: Hydroxyapatite cement, a new biomaterial that is being marketed as a method for reconstructing cranial defects, offers many advantages. We document, herein, the complete dissolution and failure of this material to set in a surgically dry field, under optimal conditions, an occurrence that has not been previously reported. CLINICAL PRESENTATION: Hydroxyapatite cement was used for reconstruction of a frontal bone defect secondary to a traumatic depressed cranial fracture in a 9-year-old male patient. At the time of suture removal on postoperative Day 6, we observed serous discharge from the wound, a reappearance of the cranial defect, and brain pulsations visible subcutaneously. INTERVENTION: The patient was returned to the operating room, at which time we learned that the hydroxyapatite cement had migrated out of the defect; small concretions of the cement were scattered throughout the subgaleal space. The concretions of cement in the subgaleal space and the small amount of cement remaining in the defect were removed, and titanium mesh was used. An excellent cosmetic result was achieved. CONCLUSION: Although offering many advantages, hydroxyapatite cement does carry a risk of failure to set, despite optimal technique. Causes for failure to set, as well as possible modifications in the use of material and technique, are discussed.

Neurosarcoid infiltration of the ventricular catheter causing shunt failure: a case report.

BACKGROUND: Neurosarcoid is known to develop in 5% of patients with sarcoidosis. A frequent manifestation of this condition is hydrocephalus, which will often require treatment with a ventricular shunt. METHODS: Presented here is the case of a patient whose initial manifestation of neurosarcoidosis was hydrocephalus, and who then represented with multiple shunt failures. RESULTS: On two revisions, the proximal catheter, after removal, was found to be occluded with noncaseating granulomatous material that had infiltrated the shunt lumen. CONCLUSIONS: Although shunts may become occluded by inspissated proteinaceous or cellular debris, the occlusion of a shunt catheter by the ingrowth of the noncaseating granulomatous material of neurosarcoid has not been described before. This patient's course, the histopathologic findings, and neurosarcoidosis in general are discussed here.

Cerebral aneurysm in the HIV patient: a report of six cases.

BACKGROUND: In view of the almost certain mortality of the acquired immune deficiency syndrome (AIDS) patient, controversy may arise as to how to treat those individuals with concomitant aneurysmal disease. METHODS: We conducted a retrospective case review of six patients seen in a 1-year period, who had a history of either being positive for human immunodeficiency virus (HIV) or prior opportunistic pneumonias and who, therefore, by Centers for Disease Control definition, have frank AIDS. The patients, who were in otherwise stable health, presented with subarachnoid hemorrhage from angiographically demonstrated ruptured berry aneurysms. RESULTS: There was no increased incidence of postoperative infections and the quality of life of the surviving five patients was quite good. CONCLUSIONS: In a patient in stable health, the diagnosis of HIV infection should not necessarily preclude the established regimen for the treatment of aneurysmal disease.

Preoperative MRI diagnosis of Lhermitte-Duclos disease: case report with associated enlarged vessel and syrinx.

BACKGROUND: The most common primary cerebellar tumor is hemangioblastoma, a lesion which is associated with magnetic resonance imaging (MR)-detectable vascularity in over 60%. Lhermitte-Duclos disease is an uncommon cause of a cerebellar mass that is not typically vascular. METHODS: Computed tomography (CT), MRI with and without contrast, and magnetic resonance venography was performed in a patient with a cerebellar mass. RESULTS: The cerebellar mass was noted to have a prominent vessel, as well as an associated syrinx. In spite of MRI-detectable vascularity, the striped appearance of the lesion was felt to be typical of Lhermitte-Duclos disease. At surgery, the mass was resected and the diagnosis of Lhermitte-Duclos disease was confirmed. CONCLUSIONS: The diagnosis of Lhermitte-Duclos disease should be made when MRI shows a parallel linear "tiger-striped" lesion of the cerebellum. The presence of an enlarged vessel and/or syrinx should not deter one from making the preoperative diagnosis.

Rapid recurrence of craniopharyngioma during pregnancy with recovery of vision: a case report.

Although enlargement of pituitary adenomas during pregnancy is a well documented phenomenon, this is rarely seen with craniopharyngiomas. Discussed here is the case of a patient whose initial presentation, operation, rapid regrowth, and reoperation of a pathologically proven solid craniopharyngioma, occurred during the course of a single pregnancy. Further, the rapid regrowth of the tumor resulted in total blindness for 48 hours prior to reoperation. Repeat transsphenoidal operation resulted in a gross total removal, restoration of vision, and allowed for the cesarean section delivery of a healthy infant.

Candidal pituitary abscess: case report.

We report a case of a culture-proven intrasellar Candida albicans abscess. A 36-year-old woman presented with a history of headaches, menstrual irregularities, and mild symptoms of diabetes insipidus. She was neurologically intact at the time of a transsphenoidal surgery for a presumed pituitary adenoma. An extensive work-up revealed that although the patient was seronegative for human immunodeficiency virus, she was immunocompromised with a T-cell dysfunction. Fungal abscesses of the pituitary gland have rarely been reported. This is the first documented case of a patient who is seronegative for human immunodeficiency virus who becomes infected by an ordinarily innocuous fungus, Candida albicans.

Halifax clamps: efficacy and complications in posterior cervical stabilization.

BACKGROUND: Trauma, neoplasia, rheumatoid arthritis, Down's syndrome, and inflammatory conditions are well-known causes of spinal instability. The Halifax clamp is a method of posterior cervical stabilization that is attached to the adjoining laminae and tightened until no movement between involved vertebrae is possible. Our experience with cases that have utilized Halifax interlaminar clamps, their results and complications are presented. METHODS: We conducted a retrospective review of patients with spinal instability in whom Halifax interlaminar clamps were utilized for posterior spinal stabilization. RESULTS: Over a 5-year period, 38 patients in our institution underwent posterior stabilization of the cervical spine utilizing the Halifax interlaminar clamp. The patients represent a mix of motor vehicle- and sports-related traumas, rheumatoid subluxation, and a single cancer patient. Average follow-up has been 29 months (range 3 to 36 months). Thirty (78.9%) patients have had good results (i.e., stable fusion and regression of symptoms) and no complications. Three patients from our institution, and a fourth patient referred to us postoperatively, developed complications related to the Halifax clamps. Four patients died from unrelated causes. CONCLUSIONS: Halifax interlaminar clamps are a safe and effective method for posterior stabilization of various causes of cervical spinal instability.

Transoral gunshot wounds to the atlanto-axial complex: report of five cases.

Although there has been a rise in the incidence of gunshot wounds to the spine in the United States, involvement of the upper cervical spine, i.e., the atlanto-axial complex, remains rare. Management strategies for these types of injuries come from wartime as well as civilian experience, however, they are not uniformly agreed upon. Treatment strategies are aimed at both stabilization of bony structures and preservation of neurologic function. This report documents five neurologically intact patients who sustained gunshot wounds to the atlanto-axial complex, their management, and follow-up results.

Cardiovascular responses to global cerebral ischemia: role of excitatory amino acids in the ventrolateral medullary pressor area.

The object of this study was to investigate the role of the ventrolateral medullary pressor area in mediating the cardiovascular responses to experimentally induced global cerebral ischemia, and to test if excitatory amino acids or acetylcholine are the transmitters released in this brain region during these responses. The cerebral ischemic response was elicited in pentobarbital-anesthetized, artificially ventilated male Wistar rats by bilateral ligation of vertebral arteries followed by temporary clamping of the common carotid arteries. The pressor area was identified by microinjections of L-glutamate. Inhibition of neurons in this area by microinjections of muscimol, a gamma-aminobutyric acid receptor agonist, abolished the ischemic response, which demonstrated that this area is important in mediating these responses. Microinjections of a broad-spectrum excitatory amino acid receptor blocker (kynurenate), of specific antagonists for N-methyl-D-aspartic acid (NMDA) and non-NMDA receptors (injected alone or in combination), and of atropine failed to block the ischemic responses. These results indicate that: 1) the ventrolateral medullary pressor area mediates pressor responses to cerebral ischemia, and 2) excitatory amino acids or acetylcholine in this area do not mediate the cardiovascular responses to cerebral ischemia.

Epidural trial in implantation of intrathecal morphine infusion pumps.

This retrospective review permits limited conclusions due to the small sample size and the limited control of variables. The temporary prepump, percutaneous epidural catheter trial is a useful component of our protocol. This period provides important information relative to possible side effects and efficacy of pain. The trial does give an estimation for the starting point of the intrathecal dosage but, as we have demonstrated, this is, at times, at a greater dosage than previously had been predicted. We feel that this retrospective review supports the continued use of a prepump trial of epidural morphine prior to permanent intrathecal pump implantation.