Noninvasive localization of brain-stem lesions in the cat with multimodality evoked potentials

1981 ◽  
Vol 54 (6) ◽  
pp. 740-750 ◽  
Author(s):  
Richard P. Greenberg ◽  
Donald M. Stablein ◽  
Donald P. Becker
Keyword(s):  
Evoked Potentials ◽  
Brain Stem ◽  
Evoked Potential ◽  
Animal Experiments ◽  
Content Type ◽  
Central Nervous System Dysfunction ◽  
Multimodality Evoked Potentials ◽  
Stem Lesions ◽  
The Brain ◽  
Fine Print

✓ Multimodality evoked potential (MEP) data from over 300 comatose head-injured patients suggest that central nervous system dysfunction of the brain stem and/or hemispheres can be localized with this noninvasive neuroelectric technique. Based on this work, decerebrate motor posturing and prolonged coma are not associated with brain-stem dysfunction but rather with dysfunction of the hemispheres, while absent pupillary and oculocephalic responses are correlated with brain-stem dysfunction alone. However, the accuracy with which MEP data localized human brain-stem or hemispheric dysfunction could not be confirmed by pathological correlation because of low mortality and the small number of autopsies obtained in the patients who died. Therefore, this study was undertaken in an animal model of brain-stem lesion. Complete brain-stem transections were made at the cervicomedullary junction, the medulla just caudal to the eighth nerve, and at the intercollicular region. All cortical visual evoked potential (VEP) peaks were reduced in amplitude and delayed by each of the brain-stem transections, but none of the peaks was abolished. In spite of brain-stem transection, VEP's can be used to gain information about hemispheric function. Somatosensory (SEP) and auditory cortically generated evoked potentials (AEP) were abolished by these brain-stem transections, but early-latency brain-stem SEP and AEP data could accurately localize specific areas of brain-stem dysfunction caused by the lesions. Observations made on human MEP data seem to be confirmed by these animal experiments. Correlations between human and cat MEP data are discussed.

A study of safe entry zones via the floor of the fourth ventricle for brain-stem lesions

1993 ◽  
Vol 78 (6) ◽  
pp. 987-993 ◽  
Author(s):  
Kazuhiko Kyoshima ◽  
Shigeaki Kobayashi ◽  
Hirohiko Gibo ◽  
Takayuki Kuroyanagi
Keyword(s):  
Facial Nerve ◽  
Brain Stem ◽  
Fourth Ventricle ◽  
Medial Lemniscus ◽  
Content Type ◽  
Brain Stem Lesions ◽  
Stem Lesions ◽  
Hazardous Procedure ◽  
The Brain ◽  
Fine Print

✓ Direct surgery for intra-axial lesions of the brain stem is considered a hazardous procedure, and morbidity of varying degrees cannot be avoided even with partial removal or biopsy. The main causes of morbidity relate to direct damage during removal of the lesion, selection of an entry route into the brain stem, and the direction of brain stem retraction. The authors examined the possibility of making a medullary incision and retracting the brain stem, taking into account the symptomatology and surgical anatomy, and found two safe entry zones into the brain stem through a suboccipital approach via the floor of the fourth ventricle. These safe entry zones are areas where important neural structures are less prominent. One is the “suprafacial triangle,” which is bordered medially by the medial longitudinal fascicle, caudally by the facial nerve (which runs in the brainstem parenchyma), and laterally by the cerebellar peduncle. The second is the “infrafacial triangle,” which is bordered medially by the medial longitudinal fascicle, caudally by the striae medullares, and laterally by the facial nerve. In order to minimize the retraction-related damage to important brain-stem structures, the brain stem should be retracted either laterally or rostrally in the suprafacial triangle approach and only laterally in the infrafacial triangle approach. Three localized intra-axial brain-stem lesions were treated surgically via the safe entry zones using the suprafacial approach in two and the infrafacial approach in one. The cases are described and the approaches delineated. Both approaches are indicated for focal intra-axial lesions located unilaterally and dorsal to the medial lemniscus in the lower midbrain to the pons. Magnetic resonance imaging is useful in selecting these approaches, and intraoperative ultrasonography is helpful to confirm the exact location of a lesion before a medullary incision is made. These approaches can also be used as routes for aspiration of brain-stem hemorrhage as well as for tumor biopsy.

Measurements of brain-stem auditory evoked potentials in patients with spontaneous intracerebral hemorrhage

1984 ◽  
Vol 60 (3) ◽  
pp. 548-552 ◽  
Author(s):  
Christianto B. Lumenta
Keyword(s):  
Glasgow Coma Scale ◽  
Intracerebral Hemorrhage ◽  
Evoked Potentials ◽  
Brain Stem ◽  
Auditory Evoked Potentials ◽  
Spontaneous Intracerebral Hemorrhage ◽  
Content Type ◽  
Different Types ◽  
The Brain ◽  
Fine Print

✓ Brain-stem auditory evoked potentials (BAEP's) were recorded in 19 patients with spontaneous intracerebral hemorrhage. More than half of the patients were deeply comatose. There was no correlation between BAEP changes and different types of spontaneous intracerebral hemorrhage or between BAEP's and coma grading by the Glasgow Coma Scale. However, BAEP's were a significant prognostic aid in these cases and useful in indicating the level of the brain-stem lesion.

Arteriovenous malformations in the posterior fossa

1977 ◽  
Vol 47 (1) ◽  
pp. 50-56 ◽  
Author(s):  
Hiroshi Matsumura ◽  
Yasumasa Makita ◽  
Kuniyuki Someda ◽  
Akinori Kondo
Keyword(s):  
Arteriovenous Malformation ◽  
Brain Stem ◽  
Posterior Fossa ◽  
Arteriovenous Malformations ◽  
Cerebellopontine Angle ◽  
Anterior Part ◽  
Content Type ◽  
The Brain ◽  
Fine Print

✓ We have operated on 12 of 14 cases of arteriovenous malformation (AVM) in the posterior fossa since 1968, with one death. The lesions were in the cerebellum in 10 cases (three anteromedial, one central, three lateral, and three posteromedial), and in the cerebellopontine angle in two; in two cases the lesions were directly related to the brain stem. The AVM's in the anterior part of the cerebellum were operated on through a transtentorial occipital approach.

Cervical spinal cord in experimental hydrocephalus

1972 ◽  
Vol 37 (5) ◽  
pp. 538-542 ◽  
Author(s):  
George J. Dohrmann
Keyword(s):  
Spinal Cord ◽  
Brain Stem ◽  
Cervical Spinal Cord ◽  
Central Canal ◽  
Content Type ◽  
Experimental Hydrocephalus ◽  
Physiological Pressure ◽  
The Brain ◽  
Shunting Procedure ◽  
Fine Print

✓ Adult dogs were rendered hydrocephalic by the injection of kaolin into the cisterna magna. One group of dogs was sacrificed 1 month after kaolin administration, and ventriculojugular shunts were performed on the other group. Hydrocephalic dogs with shunts were sacrificed 1 day or 1 week after the shunting procedure. All dogs were perfused with formalin at physiological pressure, and the brain stem and cervical spinal cord were examined by light microscopy. Subarachnoid granulomata encompassed the superior cervical spinal cord and dependent surface of the brain stem. Rarefaction of the posterior white columns and clefts or cavities involving the gray matter posterior to the central canal and/or posterior white columns were present in the spinal cords of both hydrocephalic and shunted hydrocephalic dogs. Predominantly in the dogs with shunts, hemorrhages were noted in the spinal cord in association with the clefts or cavities. A mechanism of ischemia followed by reflow of blood is postulated to explain the hemorrhages in the spinal cords of hydrocephalic dogs with shunts.

Intraoperative monitoring of brain-stem auditory evoked potentials

1982 ◽  
Vol 57 (5) ◽  
pp. 674-681 ◽  
Author(s):  
Betty L. Grundy ◽  
Peter J. Jannetta ◽  
Phyllis T. Procopio ◽  
Agnes Lina ◽  
J. Robert Boston ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Brain Stem ◽  
Auditory Nerve ◽  
Intraoperative Monitoring ◽  
Cerebellopontine Angle ◽  
Auditory Evoked Potentials ◽  
Irreversible Loss ◽  
Content Type ◽  
Complete Obliteration ◽  
Fine Print

✓ Brain-stem auditory evoked potentials (BAEP) were monitored during 54 neurosurgical operations in the cerebellopontine angle. The BAEP were irreversibly obliterated in five patients who required deliberate section of the auditory nerve. Technical difficulties interfered with monitoring in three cases, and three patients had deafness and absent BAEP preoperatively. Reversible alterations in BAEP were seen during 32 operations, with recovery after as long as 177 minutes of virtually complete obliteration. Changes in BAEP were associated with surgical retraction, operative manipulation, positioning of the head and neck for retromastoid craniectomy, and the combination of hypocarbia and moderate hypotension. In 19 cases, waveforms improved after specific interventions made by the surgeon or anesthesiologist because of deteriorating BAEP. In 13 other cases, BAEP recovered after maneuvers not specifically related to the electrophysiological monitoring, most often completion of operative manipulation. Whenever BAEP returned toward normal by the end of anesthesia, even after transient obliteration, hearing was preserved. Irreversible loss of BAEP occurred only when the auditory nerve was deliberately sacrificed. The authors conclude that monitoring of BAEP may help prevent injury to the auditory nerve and brain stem during operations in the cerebellopontine angle.

Neurophysiological effects of dorsal column stimulation in man and monkey

1974 ◽  
Vol 41 (2) ◽  
pp. 217-223 ◽  
Author(s):  
Sanford J. Larson ◽  
Anthony Sances ◽  
Donald H. Riegel ◽  
Glenn A. Meyer ◽  
Donald E. Dallmann ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Evoked Potentials ◽  
Evoked Potential ◽  
Intractable Pain ◽  
Current Application ◽  
Content Type ◽  
Bipolar Recording ◽  
Stimulating Electrodes ◽  
Recording Electrodes ◽  
Fine Print

✓ In 18 patients with cancer and intractable pain, capacitatively coupled pulses of 0.25 msec duration were delivered transcutaneously at 100 Hz to sets of five in-line electrodes implanted subdurally over the dorsal columns. Averaged somatosensory-evoked potentials were recorded from scalp electrodes before, during, and after application of current. All but one patient experienced relief of pain during stimulation, persisting for as long as several hours afterward. Eleven patients developed hyperactive deep reflexes, pathological reflexes, and decreased perception of joint rotation, pain, and touch below the level of current application. Somatosensory-evoked potential amplitudes were markedly reduced. All neurological findings returned to control values within 1 hour after each of repeated applications of current. Histological examination of spinal cord sections from four cancer patients showed no changes secondary to long-term current application. Similar currents were applied to the spinal cord of 15 monkeys with chronically implanted bipolar recording or stimulating electrodes over the lower, middle, and upper thoracic cord, in nucleus ventralis posterior lateralis (VPL), and over the sensory motor cortex (SMC). With application of current, the responses in VPL and SMC to peripheral stimulation were abolished. Evoked potential responses were abolished between bipolar stimulating electrodes and bipolar recording electrodes separated by the five in-line electrodes used to supply the 100 Hz current. However, when both stimulating and recording electrodes were either above or below the five in-line electrode set, evoked responses were unaffected. The findings indicate that applied currents blocked neuronal transmission by producing local changes in the cord. The prolonged alteration of cerebral evoked potentials and relief of pain, however, could also be related to involvement of supraspinal neurons.

Cerebral cysticercosis with aqueductal obstruction

1980 ◽  
Vol 53 (2) ◽  
pp. 252-255 ◽  
Author(s):  
Tung Pui Poon ◽  
Edward J. Arida ◽  
Wolodymyr P. Tyschenko
Keyword(s):  
Intracranial Hypertension ◽  
Brain Stem ◽  
Normal Pressure Hydrocephalus ◽  
Signs And Symptoms ◽  
Normal Pressure ◽  
Content Type ◽  
Neurological Signs ◽  
Cerebral Cysticercosis ◽  
The Brain ◽  
Fine Print

✓ The authors report a case of cerebral cysticercosis which presented with generalized nonspecific neurological signs and symptoms attributed to acute aqueductal obstruction, with concomitant intracranial hypertension. These were characteristic intracranial calcifications along with angiographically demonstrated signs of hydrocephalus. Contrast encephalography clearly demonstrated aqueductal obstruction. Pathologically, the aqueductal obstruction was shown to be due to parasitic invasion of the brain stem with compression of the aqueduct. The presence of typical intracranial calcification in conjunction with either obstructive or normal-pressure hydrocephalus should alert the observer to the possibility of cerebral cysticercosis.

Odontoid compression of the brain stem in a patient with rheumatoid arthritis

1980 ◽  
Vol 53 (6) ◽  
pp. 841-845 ◽  
Author(s):  
Harold P. Smith ◽  
Venkata R. Challa ◽  
Eben Alexander
Keyword(s):  
Rheumatoid Arthritis ◽  
Brain Stem ◽  
Neurological Deficit ◽  
Neurological Symptoms ◽  
Direct Compression ◽  
Content Type ◽  
Vertical Subluxation ◽  
Progressive Neurological Deficit ◽  
The Brain ◽  
Fine Print

✓ Cervical spine involvement by rheumatoid arthritis is common; brain-stem compression secondary to vertical subluxation of the odontoid in patients with rheumatoid arthritis is rare. Vertical subluxation results from 1) destruction of the transverse atlantal, apical, and alar ligaments of the atlas and odontoid, and 2) bone resorption in the occipital condyles, lateral masses of the atlas, and basilar processes of the skull. Neurological symptoms result from direct compression of the brain stem or from ischemia secondary to compression of vertebral arteries, anterior spinal arteries, or small perforating arteries of the brain stem and spinal cord. A case is reported in which a slowly progressive neurological deficit developed in a woman with rheumatoid arthritis following a fall from a stretcher. Neurological symptoms represented direct compression of the medulla by the dens, a mechanism confirmed at operation and autopsy. Recognition of progressive neurological deficit is often difficult in patients with rheumatoid arthritis because of their inactivity and their atrophic and immobile joints, but is essential if appropriate decompressive or stabilizing procedures are to be done. In patients with vertical subluxation of the dens, the transoral approach with removal of the odontoid is recommended. Decompression should be extensive, including the fibrous capsule around the odontoid and overlying synovial tissue as well as the odontoid itself.

Intraoperative identification of motor areas of the rhomboid fossa using direct stimulation

1993 ◽  
Vol 79 (3) ◽  
pp. 393-399 ◽  
Author(s):  
Christian Strauss ◽  
Johann Romstöck ◽  
Christopher Nimsky ◽  
Rudolf Fahlbusch
Keyword(s):  
Brain Stem ◽  
Fourth Ventricle ◽  
Complete Removal ◽  
Direct Stimulation ◽  
Content Type ◽  
Rhomboid Fossa ◽  
Stem Lesions ◽  
Mass Lesions ◽  
The Brain ◽  
Motor Areas

✓ Intraoperative electrical identification of motor areas within the floor of the fourth ventricle was successfully carried out in a series of 10 patients with intrinsic pontine lesions and lesions infiltrating the brain stem. Direct electrical stimulation was used to identify the facial colliculus and the hypoglossal triangle before the brain stem was entered. Multichannel electromyographic recordings documented selective stimulation effects. The surgical approach to the brain stem was varied according to the electrical localization of these structures. During removal of the lesion, functional integrity was monitored by intermittent stimulation. In lesions infiltrating the floor of the fourth ventricle, stimulation facilitated complete removal. Permanent postoperative morbidity of facial or hypoglossal nerve dysfunction was not observed. Mapping of the floor of the fourth ventricle identifies important surface structures and offers a safe corridor through intact nervous structures during surgery of brain-stem lesions. Reliable identification is particularly important in mass lesions with displacement of normal topographical anatomy.

Vascular malformations of the brain stem

1989 ◽  
Vol 70 (6) ◽  
pp. 847-852 ◽  
Author(s):  
Douglas Chyatte
Keyword(s):  
Brain Stem ◽  
Vascular Malformation ◽  
Vascular Malformations ◽  
Surgical Removal ◽  
Content Type ◽  
Appropriate Treatment ◽  
Complete Obliteration ◽  
Time Of Presentation ◽  
The Brain ◽  
Fine Print

✓ Vascular malformations of the brain stem are unusual lesions that may pose a diagnostic and therapeutic challenge. Seven patients with vascular malformations involving the brain stem were evaluated; six were treated surgically, with complete obliteration of the lesion in five patients. In five patients symptoms developed only after a hemorrhage had occurred, and three of these suffered a rebleed before appropriate treatment was given. Angiography failed to demonstrate lesions in three cases, which did not appear to protect from repeat hemorrhage since two of the three rebled. There were no operative deaths, and no patients were made permanently worse after surgery. Useful recovery occurred commonly after appropriate treatment and appeared to be possible even in patients who had suffered a catastrophic neurological deficit at the time of presentation. These data indicate that surgical removal of the lesion may be warranted in some patients with symptomatic brain-stem vascular malformation.

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