Intracranial vascular anastomosis using the microanastomotic system. Technical note

The authors describe the use of a microanastomotic device to perform intracranial end-to-end vascular anastomoses. Direct end-to-end anastomosis was performed between the superficial temporal artery and branches of the middle cerebral artery (MCA) in three patients. Two patients had moyamoya disease, with severe proximal MCA disease, and one suffered an internal carotid artery occlusion with poor collateral flow. All patients reported a history of recent ischemic symptoms. Each anastomosis was accomplished in less than 15 minutes with technically satisfactory results. Postoperative angiographic studies demonstrated patency of the bypasses in all patients.

Complement depletion reduces macrophage infiltration and activation during Wallerian degeneration and axonal regeneration

After peripheral nerve injury, macrophages infiltrate the degenerating nerve and participate in the removal of myelin and axonal debris, in Schwann cell proliferation, and in axonal regeneration. In vitro studies have demonstrated the role serum complement plays in both macrophage invasion and activation during Wallerian degeneration of peripheral nerve. To determine its role in vivo, we depleted serum complement for 1 week in adult Lewis rats, using intravenously administered cobra venom factor. At 1 d after complement depletion the right sciatic nerve was crushed, and the animals were sacrificed 4 and 7 d later. Macrophage identification with ED-1 and CD11a monoclonal antibodies revealed a significant reduction in their recruitment into distal degenerating nerve in complement-depleted animals. Complement depletion also decreased macrophage activation, as indicated by their failure to become large and multivacuolated and their reduced capacity to clear myelin, which was evident at both light and electron microscopic levels. Axonal regeneration was delayed in complement-depleted animals. These findings support a role for serum complement in both the recruitment and activation of macrophages during peripheral nerve degeneration as well as a role for macrophages in promoting axonal regeneration.

Magnetic resonance neurography for cervical radiculopathy: a preliminary report

Magnetic resonance neurography was used to directly image cervical spinal nerves in patients with clinical and radiographic evidence of cervical radiculopathy. A magnetic resonance imaging phased-array coil system was used to obtain high-resolution coronal T1-weighted spin echo, coronal/axial T2-weighted fast spin echo with fat saturation, and coronal/axial fast short tau inversion recovery weighted images of the cervical spine and spinal nerves. Three patients with neck and upper extremity pain and one asymptomatic volunteer were studied. The T2-weighted and the fast short tau inversion recovery images demonstrated markedly increased signal in the proximal portion of the affected spinal nerves. In two patients, contrast-to-noise measurements of the affected spinal nerves showed a markedly increased intensity compared with that of the noninvolved spinal nerves. Our findings demonstrate that phased-array coils used in conjunction with magnetic resonance neurography sequences can detect signal abnormalities within compressed cervical spinal nerves in patients with corresponding radicular symptoms and findings. This technique may prove to be helpful in evaluating patients with multilevel disc and/or spondylotic disease of the cervical spine.

Differential macrophage responses in the peripheral and central nervous system during wallerian degeneration of axons

We characterized quantitatively the macrophage response following axonal injury in both the peripheral (PNS) and central nervous system (CNS) of adult mammals. A monoclonal antibody (ED-1) which stains monocytes, macrophages, and activated microglia was employed. In one model, Wallerian degeneration of the sciatic nerve was studied. An increase in the number of macrophages was seen as early as 1 day following nerve transection. Macrophage number increased synchronously along the length of degenerating nerve over a 21-day period. In a second model, transection of a spinal dorsal sensory root allowed us to compare and contrast the macrophage response along the PNS and CNS portions of a single axonal pathway. An increased number of macrophages restricted to the PNS portion of this pathway was seen by 3 days and continued to increase over a 14-day period. Myelin breakdown occurred in association with an increase in the number of macrophages by 3 days in the PNS but not the CNS portion of the degenerating dorsal root axon pathway. Low-affinity nerve growth factor receptor immunohistochemical staining increased by Day 1 in the PNS but not the CNS portion of this pathway, occurring prior to the invasion of macrophages. In both models, the morphology of infiltrating macrophages changed over time from small slender ramified cells to large elongated multivacuolated cells. In conclusion, our results demonstrate that the macrophage response during Wallerian degeneration of axons in adult mammals is much more rapid and robust in the PNS, where axonal regeneration occurs, than in the CNS, where axonal regeneration is far more limited.

The pathophysiology of oral pharyngeal apraxia and mutism following posterior fossa tumor resection in children

Mutism following posterior fossa tumor resection in pediatric patients has been previously recognized, although its pathophysiology remains unclear. A review of the available literature reveals 33 individuals with this condition, with only a few adults documented in the population. All of these patients had large midline posterior fossa tumors. To better understand the incidence and anatomical substrate of this syndrome, the authors reviewed a 7-year series of 110 children who underwent a posterior fossa tumor resection. During that time, nine (8.2%) of the 110 children exhibited mutism postoperatively. They ranged from 2.5 to 20 years of age (mean 8.1 years) and became mute within 12 to 48 hours of surgery. The period of mutism lasted from 1.5 to 12 weeks after onset: all children had difficulty coordinating their oral pharyngeal musculature as manifested by postoperative drooling and inability to swallow. Further analysis of these cases revealed that all children had splitting of the entire inferior vermis at surgery, as confirmed on postoperative magnetic resonance studies. Lower cranial nerve function was intact in all nine patients. Current concepts of cerebellar physiology emphasize the importance of the cerebellum in learning and language. The syndrome described resembles a loss of learned activities, or an apraxia, of the oral and pharyngeal musculature. To avoid the apraxia, therefore, the inferior vermis must be preserved. For large midline tumors that extend to the aqueduct, a combined approach through the fourth ventricle and a midvermis split may be used to avoid injuring the inferior vermis.

Emergent aneurysm clipping without angiography in the moribund patient with intracerebral hemorrhage: the use of infusion computed tomography scans

The authors report their experience with 25 patients (mean age, 44.3 +/- 12.1 years) with an intracerebral hematoma (ICH) from a ruptured aneurysm who were emergently operated on without angiography. Instead, preoperative high-resolution infusion computed tomography (CT) scans were used to identify the aneurysm causing the hemorrhage. In all patients, the preoperative Glasgow Coma Scale score was < 5 and brain stem compression was evident. ICH was present in the frontal or temporal lobe and was often associated with intraventricular hemorrhage (n = 17) and significant (> 1 cm) midline shift (n = 18). Infusion CT scans correctly identified the aneurysm in all patients (middle cerebral artery, 18; posterior communicating artery, 2; carotid bifurcation, 3; anterior communicating artery, 2). Partial evacuation of the hematoma guided by infusion CT scan was usually required first to clip the aneurysm definitively using standard microvascular techniques. Intraoperative rupture occurred twice, and temporary clips were used on four occasions. Lobectomy (n = 8), decompressive craniotomy (n = 15), and ventriculostomy (n = 8) were required to control cerebral swelling. All patients underwent postoperative angiography to confirm aneurysm obliteration. Eleven unruptured aneurysms were subsequently identified. Nine had been predicted by infusion scan. Twelve patients survived, eight of whom were only moderately disabled and were independent at 6-months' follow-up. Of the 13 patients who died, all except one died within 4 days of admission. The authors conclude that although angiographic verification before aneurysm surgery is preferable, in the moribund patient with intracerebral hemorrhage, infusion CT scanning provides sufficient information concerning vascular anatomy to allow rational emergency craniotomy and aneurysm clipping.

Paragangliomas of the sellar region: report of two cases

Two cases of paraganglioma arising from the parasellar region are presented. Both occurred in middle-aged women who sought treatment of headaches but who had no endocrinological dysfunction; one case was associated with ophthalmoplegia from cavernous sinus involvement. Diagnosis in both cases was confirmed by typical histological appearance and cytochemical demonstration of immunoreactive chromogranin in tumor cells. The pathological features and possible pathogenesis of parasellar paragangliomas are discussed.

Resolution of an actinomycotic abscess with nonsurgical treatment: case report

A case of actinomycotic brain abscess is presented. Conservative treatment by prolonged administration of antibiotics after needle biopsy showed complete resolution of the abscess. Previously reported cases suggest that definitive treatment requires excision or open surgical drainage of the abscess. The case presented suggests an alternative approach to treating this unusual cause of brain abscess.

Uptake of fatty acids and their mobilization from phospholipids in cultured monocyte-macrophages from rheumatoid arthritis patients

Prostaglandins (PG) and related eicosanoids which derive from essential fatty acids are important mediators and modulators of inflammation. Macrophages (M phi), which derive from peripheral blood monocytes (PBM), are prominent cells in the synovium of patients with rheumatoid arthritis (RA), and are a major source of synovial PGE2. In addition, fresh and cultured PBM from RA patients produce more PG than normal control cells. When allowed to mature in culture PBM exhibit many characteristics of macrophages (M-M phi). We examined uptake by M-M phi of eicosanoid precursor fatty acids (FA), their incorporation into cellular phospholipid (PL), and mobilization of FA after cell stimulation. Cultured M-M phi from treated and untreated RA patients (RA M-M phi) took up significantly more linoleic acid (LA), dihomogammalinolenic acid (DHLA) and arachidonic acid (AA) than M-M phi from normal volunteers (N M-M phi). The enhanced uptake of FA observed in 12-day cultures of RA M-M phi was similar to uptake seen in normal human peritoneal macrophages (PM phi). After uptake FA were incorporated mainly into phosphatidylcholine (PC). M-M phi from untreated RA patients incorporated a smaller proportion of [14C]LA into PC (37.0 +/- 12.7% of total PL label) than normal cells (86.0 +/- 4.2%), and a greater proportion of [3H]AA into PC (57.1 +/- 7.1%) than normals (23.9 +/- 6.9%). Stimulation of M-M phi with calcium ionophore A23187 resulted in significantly greater hydrolysis of LA and AA from PC in RA M-M phi from both treated and untreated patients than from PC in N M-M phi. The data indicate that M-M phi from RA patients mature more rapidly in vitro than M-M phi from controls as uptake of FA by RA M-M phi increases with duration of culture and by 12 days in culture equals uptake by normal human peritoneal M phi. Also, RA M-M phi exhibit differences from N M-M phi in uptake, PL distribution, and hydrolysis of eicosanoid precursor FA. Such changes in FA metabolism might influence cell function and inflammatory responses.