Biomedical subjects

Eric L Zager

Publications and source records attributed to Eric L Zager.

23 records · Page 2Linked to original sources

PubMed2003

Intracranial hypotension after intraoperative lumbar cerebrospinal fluid drainage.

OBJECTIVE: Intraoperative lumbar cerebrospinal fluid drainage is frequently performed in a variety of neurosurgical procedures. A retrospective review is presented of the complications of lumbar cerebrospinal fluid drainage. METHODS: The records from 75 consecutive operations requiring intraoperative lumbar cerebrospinal drainage during a 1-year period at the Hospital of the University of Pennsylvania were reviewed to assess the types of complications attributable to spinal drainage and their rates of occurrence. The operations were categorized into 46 aneurysm clippings, 21 craniotomies for tumors, and 8 other cranial base procedures. RESULTS: Two patients developed transient postoperative neurological complications as a result of intracranial hypotension that resolved after epidural blood patching, with a reexploration craniotomy to drain an epidural collection performed in one patient. A third patient in the study developed a persistent deficit when intracranial hypotension led to intraoperative transtentorial herniation, which resulted in an unusual constellation of multiple brainstem infarcts that caused cranial neuropathy. CONCLUSION: Complications of intraoperative lumbar cerebrospinal fluid drainage resulting in transient (2 of 75 patients, 3%) or persistent (1 of 75 patients, 1%) neurological deficits caused by intracranial hypotension occur infrequently and may be related to preexisting conditions such as hydrocephalus.

Adult↗

PubMed2003

Thalamic deep brain stimulation for disabling tremor after excision of a midbrain cavernous angioma. Case report.

Thalamic deep brain stimulation (DBS) has been demonstrated to be effective for the treatment of parkinsonian or essential tremor. To date, however, few data exist to support the application of this method to treat midbrain tremor. A 24-year-old right-handed man underwent radiosurgery and subsequent resection of a recurrently hemorrhaging cavernous angioma located in the left side of the midbrain. The surgery exacerbated severe choreoathetotic resting and action tremors of his right extremities and trunk. The patient underwent placement of a deep brain stimulator into the left ventral intermediate nucleus of the thalamus (Vim). Postoperatively, decreased truncal ataxia and right-sided choreoathetotic tremor were demonstrated, with a 57% increase in dexterity as measured by task testing. The authors demonstrate that DBS can be an effective treatment modality for disabling tremor after resection of a midbrain cavernous angioma.

Adult↗

PubMed2002

Pupil-sparing third nerve palsy with preoperative improvement from a posterior communicating artery aneurysm.

BACKGROUND: Despite the plenitude of reports concerning partial or complete third nerve palsies, especially as presenting symptoms with posterior communicating artery (PCoA) aneurysms, we present a patient with an unusual variation. CASE DESCRIPTION: A 66-year-old woman presented with progressive right-sided headaches and diplopia and was found to have a partial, pupil-sparing third nerve palsy. A small right-sided PCoA aneurysm, nearly indistinguishable from an infundibulum, was identified on magnetic resonance angiography and subsequent digital subtraction angiography. The third nerve palsy improved before surgical repair of the aneurysm. RESULTS: Microsurgical exploration revealed a small PCoA aneurysm, which was tethered to the third nerve by arachnoid adhesions. Adhesions were lysed and the aneurysm was repaired sparing the PCoA and its branches. The patient's third nerve function recovered completely postoperatively. CONCLUSIONS: Even a very small PCoA aneurysm may present with an improving, pupil-sparing partial third nerve palsy. Selection of patients for imaging studies should take this unusual variant into consideration. We describe the anatomy and potential mechanisms of this pupil-sparing third nerve palsy.

Aged↗

PubMed2002

Sensitivity of scalp EEG, cortical EGG, and somatosensory evoked responses during surgery for intracranial aneurysms.

BACKGROUND: We estimated the relative sensitivity and reliability of scalp EEG, cortical EEG and somatosensory evoked potentials (SSEPs) to detect significant changes during aneurysm surgery. METHODS: Two observers independently reviewed data from 18 patients who were monitored with scalp EEG, cortical EEG, and SSEPs to determine which if any modality demonstrated significant changes during 25 different episodes of temporary intracranial vascular occlusion. RESULTS: Kappa scores indicating the degree of agreement between the two observers were highest for the cortical strip EEG (kappa = 0.92) and the SSEPs (kappa = 0.82) and much greater than for the scalp EEG data (kappa = -0.07). The cortical strip recordings showed changes more often than either the scalp EEG or SSEP during temporary vascular occlusion. In no case did the scalp EEG change when neither the strip nor SSEP changed. In only 4% of events did the observers feel that the SSEP changed when the strip did not, but in 16% of cases, the strip changed without changes in any of the other modalities. CONCLUSIONS: Recording of EEG from strip electrodes placed on the cortical surface detects changes more frequently than either scalp EEG or SSEPs during vascular occlusion. Different observers were more likely to agree on whether the cortical strip EEG changed during vascular occlusion than the other modalities. This argues for the possible advantages of recording from strip electrodes during aneurysm surgery.

Cerebral Cortex↗

PubMed2002

Distal anterior inferior cerebellar artery aneurysms. Report of four cases.

Aneurysms of the distal anterior inferior cerebellar artery (AICA) are rare; fewer than 100 cases have been reported. The authors detail their experience with four cases and present endovascular as well as microsurgical management options. The medical records and neuroimaging studies obtained in four patients who were treated at a single institution were reviewed. Clinical presentations, neuroimaging and intraoperative findings, and clinical outcomes were analyzed. There were three men and one woman; their mean age was 43 years. Two patients presented with acute subarachnoid hemorrhage (SAH), and two presented with ataxia and vertigo (one with tinnitus, the other with hearing loss). Angiographic studies demonstrated aneurysms of the distal segment of the AICA. In one patient with von Hippel-Lindau syndrome and multiple cerebellar hemangioblastomas, a feeding artery aneurysm was found on a distal branch of the AICA. Three of the patients underwent successful surgical obliteration of their aneurysms, one by clipping, one by trapping, and one by resection along with the tumor. The fourth patient underwent coil embolization of the distal AICA and the aneurysm. All patients made an excellent neurological recovery. Patients with aneurysms in this location may present with typical features of an acute SAH or with symptoms referable to the cerebellopontine angle. Evaluation with computerized tomography, magnetic resonance (MR) imaging, MR angiography, and digital subtraction angiography should be performed. For lesions distal to branches coursing to the brainstem, trapping and aneurysm resection are viable options that do not require bypass. Endovascular obliteration is also a reasonable option, although the possibility of retrograde thrombosis of the AICA is a concern.

Adult↗