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Biomedical subjects

R G Ojemann

Publications and source records attributed to R G Ojemann.

At least 19 recordsLinked to original sources
PubMed1992

Intramedullary cavernous angiomas of the spinal cord: clinical presentation, pathological features, and surgical management.

Cavernous angiomas of the spinal cord are rare lesions that can cause severe neurological symptoms. We add a series of 6 patients with intramedullary cavernous angiomas of the spinal cord to 30 patients with 31 histologically verified lesions already described in the literature. Four types of clinical presentation were seen in the 36 patients: 1) discrete episodes of neurological deterioration with varying degrees of recovery between episodes (13 patients); 2) slow progression of neurological decline (12 patients); 3) acute onset of symptoms with rapid decline (8 patients); and 4) acute onset of mild symptoms with subsequent gradual decline lasting weeks to months (3 patients). Of the 36 patients, 25 (69%) were women and 11 (31%) were men. The peak age of presentation was in the fourth decade. The thoracic spinal cord was affected in more than half the patients, with the cervical cord being the next most common location. Histological examination demonstrated the closely apposed vascular channels characteristic of cavernous angiomas. While most vascular channels were thickened and hyalinized, three angiomas had foci of small vessels resembling a capillary angioma. The available data suggest that surgical management of intramedullary angiomas should attempt complete extirpation. The lesions are often well circumscribed with a glial plane between the lesion and normal cord. However, spinal cord angiomas, unlike cranial lesions, have little room for enlargement before devastating symptoms occur. We achieved complete excision in all of our patients, who are all ambulatory and have improved symptoms. Little, if any, increase in neurological deficit was caused by myelotomy and lesion excision. These spinal lesions should be considered for surgery early, before repeated hemorrhage or enlargement can occur.

Cross-Sectional Studies↗
PubMed1992

Preservation of hearing and facial nerve function in resection of acoustic neuroma.

The surgical results in 78 recent cases of total removal of unilateral acoustic neuroma in which an attempt was made to preserve cochlear function have been added to the authors' previous series of 66 cases to evaluate the factors influencing the ability to preserve useful hearing. Useful hearing was defined by speech reception threshold no poorer than 70 dB and a discrimination score of at least 15%. Analysis using a logistic regression model showed that certain preoperative clinical parameters such as tumor size, speech discrimination score, and gender were significantly correlated with hearing outcome. Favorable outcome was significantly correlated with smaller tumor size, higher preoperative speech discrimination score, and male sex. From this data, an explicit formula was devised for predicting hearing outcome for an individual patient. In four cases with useful hearing preserved, there was improvement of greater than 15 percentage points in speech discrimination scores. While preoperative auditory brainstem responses were not predictive of hearing preservation, monitoring of intraoperative auditory evoked potentials was predictive of hearing outcome in selected cases. Specifically, when wave V was unchanged at the end of the operation, even if it may have been transiently lost during surgery, useful hearing was invariably preserved.

Audiometry, Evoked Response↗
PubMed1992

Long-term hearing results in patients after surgical removal of acoustic tumors with hearing preservation.

Long-term hearing results are described in 18 patients after suboccipital removal of unilateral acoustic neurinomas. Follow-up ranged from 3.4 to 10.4 years with a mean of 5.4 years. Fourteen patients (78%) experienced no significant decline in long-term hearing. Four patients (22%) experienced a significant decline in long-term hearing as defined by a drop in pure-tone average (0.5, 1, and 2 kHz), or a significant decline in Speech Discrimination Scores (SDS). Changes in hearing did not correlate with tumor size, preoperative hearing, intraoperative change in hearing, the interval between initial symptoms and surgery, sex, or age.

Audiometry, Evoked Response↗
PubMed1991

Pseudopsammomatous meningioma with elevated serum carcinoembryonic antigen: a true secretory meningioma. Case report.

A sphenoid-wing meningioma in a 60-year-old woman was accompanied by elevated serum carcinoembryonic antigen (CEA) levels, which returned to normal after removal of the tumor. Light microscopic examination revealed a secretory meningioma containing numerous pseudopsammoma bodies and a prominent vascular pattern. Immunohistochemical analysis showed the tumor cells and pseudopsammoma bodies to be CEA-positive. This case illustrates the possibility that secretory meningioma may be associated with clinically detectable secretion of CEA. The report also documents the rare occurrence of elevated serum CEA in a primary benign intracranial tumor.

Carcinoembryonic Antigen↗
PubMed1990

Acute presentations of syringomyelia. Report of three cases.

Three unusual cases are reported in which communicating syringomyelia presented acutely. The first patient presented with paraplegia, the second with acute respiratory distress secondary to bilateral vocal cord paralysis, and the third with symptoms of acute brain-stem ischemia. Each patient had a communicating spinal cord syrinx associated with a posterior fossa and foramen magnum region anomaly (a huge posterior fossa arachnoid cyst in one and Chiari malformations in two). The mechanisms of craniospinal pressure dissociation and hindbrain herniation are discussed, along with other reported emergency presentations of syringomyelia.

Acute Disease↗
PubMed1989

Primary intracranial leiomyosarcoma. Case report.

A case of primary intracranial leiomyosarcoma is presented, with clinical, radiological, light microscopic, immunohistochemical, and ultrastructural data. The histogenesis is discussed and the literature on smooth-muscle tumors of the central nervous system is reviewed.

Aged↗
PubMed1988

Angiographically occult arteriovenous malformations.

Eight cases of histopathologically proven arteriovenous malformations (AVM's) which were not visualized on angiography are presented. As is typical with these lesions, most of the patients in this series presented with hemorrhage, seizures, or episodic or progressive neurological symptoms suggestive of a neoplasm. The diagnosis of angiographically occult AVM was highly suspected preoperatively in each case based on the combination of computerized tomography (CT) and magnetic resonance (MR) findings. The CT scans in all cases showed moderately hyperdense lesions which enhanced mildly or moderately in a nonhomogeneous pattern with administration of contrast material. The MR image showed one or more bright areas interspersed with areas of low or absent signal peripherally or centrally on both T1- and T2-weighted images. The AVM was totally excised in seven patients and partially excised in one patient, with favorable results in all. The clinical management and differential diagnosis of angiographically occult AVM's are discussed. In patients with a clinical course and radiological studies suggestive of an occult AVM, removal of the lesion, if accessible, should be performed in order to rule out a neoplasm and prevent subsequent hemorrhage and progression of symptoms.

Adolescent↗
PubMed1987

Preservation of hearing in surgical removal of acoustic neuromas of the internal auditory canal and cerebellar pontine angle.

The surgical results in 69 patients with unilateral tumors of the cerebellopontine angle or internal auditory canal in whom total tumor removal was accomplished, and in whom an attempt was made to preserve hearing, are presented. The success rate of preservation of hearing and facial nerve function was correlated with the size of the tumor. Useful hearing, as defined by speech reception threshold no poorer than 70 dB and a discrimination score of at least 15%, was preserved in 73% of cases in which the tumor extension to the posterior fossa was no greater than 0.5 cm. In contrast, useful hearing was preserved in 22% of cases in which posterior fossa extension was greater than 2.5 cm. No significant correlation was found between preoperative evoked responses and success in preservation of hearing. The techniques and value of intraoperative monitoring of electrocochleogram (ECoG) and brain stem evoked responses are discussed. A theory of pathogenesis of intraoperative hearing loss, based on correlation of changes in evoked responses and simultaneous surgical events, is presented.

Adult↗
PubMed1987

Emergency carotid endarterectomy.

A retrospective review of carotid endarterectomies performed by the Neurosurgical Service at Massachusetts General Hospital from July, 1976, through December, 1985, disclosed 64 procedures that were performed on an emergency basis. The patients included 40 men and 24 women, with a mean age of 64 years (range 32 to 87 years). Correlation of angiographic findings with outcome revealed that of the 27 patients with severe stenosis, usually with delay in blood flow, 25 (93%) were the same or improved postoperatively; of the 11 patients with stenosis and an intraluminal filling defect (six of whom had an intraluminal clot), eight (73%) were the same or improved after surgery; of the 16 patients with complete occlusion, 14 (88%) were the same or improved (backflow was established in all cases); and of the 10 patients with moderate to severe stenosis and/or severe ulceration (including three with transient ischemic attacks who were receiving heparin), eight (80%) were the same or improved. Pre- and postoperative clinical status were graded into five categories: intact; mild deficit; moderate deficit (significant impairment but able to perform activities of daily living); severe deficit (requiring assistance for daily activities); and death. Of the 36 patients who preoperatively were intact or had mild deficits, 33 (92%) were the same or improved postoperatively, three were worse, and there were no deaths. Among 15 patients presenting with moderate deficits, 12 (80%) were the same or improved, two were worse, and one died. Of the 13 patients with severe deficits, 10 (77%) were the same or improved and three died. Two patients with sudden severe deficits associated with loss of contralateral bruit were operated on without angiography and were intact postoperatively. Of the four deaths in the total series, two were attributed to cardiac causes and two to unrelated disease processes. The indications for emergency carotid endarterectomy are discussed.

Acute Disease↗
PubMed1987

The tradition of Harvey Cushing commemorated by a stamp in the Great American stamp series. The 1987 AANS (American Association of Neurological Surgeons) presidential address.

With the announcement that Harvey Cushing is to be honored by a United States postage stamp in the Great American stamp series, the qualities that this remarkable man possessed are reviewed--artist, author, bibliophile, scientist, soldier, physician, and teacher. The events that led to Cushing becoming a neurosurgeon are summarized. The recognition by the United States Postal Service of physicians and others who have appeared on stamps that had some relationship to Cushing's activities is discussed. Based on the tradition of Harvey Cushing, eight guidelines are presented.

History, 19th Century↗
PubMed1987

Neurotrauma care and the neurosurgeon: a statement from the Joint Section on Trauma of the AANS and CNS.

The AANS and CNS support the concept of organized neurosurgical trauma care consisting of the appropriate combination of prepared communities and institutions and of adequate numbers of committed neurosurgeons. Furthermore, we support the guidelines of the ACS regarding institutions designated to receive trauma patients, and support the concept of prehospital triage of trauma victims based upon well-trained EMS personnel guided by criteria selected by the local neurosurgical community. We support audit systems that include neurosurgeons to assess and improve the quality of neurotrauma care. By using the principles outlined above, neurosurgeons can plan, support, and evaluate whatever system their community or region requires for the optimal care of the neurotrauma patient.

Health Planning Guidelines↗
PubMed1986

MR and CT of occult vascular malformations of the brain.

The need for improved specificity in the diagnosis of "occult" vascular malformations led to the use of MR in suspected cases in order to determine MR's potential for improved diagnostic accuracy. Six patients with six lesions histologically diagnosed as vascular malformation after partial (1) or complete (5) microsurgical excision were studied by CT, MR, and selective magnification subtraction angiography. In all cases, the cerebral lesions were apparently solitary and were visible as focal lesions on both CT and MR. Since angiography failed to reveal the pathologic blood vessels of the lesions, and no arteriovenous shunting was evident, these lesions were termed vascular malformations occult to angiography (VMOTA). Angiography revealed a mass effect in only two cases. MR did not reveal additional vascular malformations missed by CT. In each case, MR, which was performed in an attempt to support the diagnosis suggested by CT, did in fact do so by revealing signal abnormalities indicative of nonacute hemorrhage within the lesion on T1- and T2-weighted pulse sequences. Although, as on CT, MR features of these lesions were found to be nonspecific, the MR criteria reinforced the probable diagnosis of VMOTA in an additional 30 cases that had shown similar nonspecific CT features. In this second group, excluded from this study, in which histologic verification was not obtained because of perceived hazards of surgery, the increased assurance regarding the diagnosis led to proton-beam therapy without histologic verification in 18 cases. It is concluded that MR can provide significant improvement in the accuracy of diagnosing VMOTA beyond that obtainable just by plain and contrast-enhanced CT.

Adult↗