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Biomedical subjects

W J Levy

Publications and source records attributed to W J Levy.

At least 73 records · Page 4Linked to original sources
PubMed1984

Transparent optical neurosurgical instruments. Technical note.

Neurosurgical instrumentation over the last two decades has improved with the increasing use of the operating microscope and has provided much better visualization and lighting of the surgical field. During this time, dissecting instruments have become smaller, but they sacrifice some of the microscopic gains because they are made of opaque metal. This has the disadvantage of hiding from the surgeon the area of the surgical field being worked on. This paper reports the development of transparent instruments that are strong enough to be used in dissection and yet do not sacrifice part of the improved visualization and lighting gained with the operating microscope. Made of a high-strength plastic, these instruments can be used for dissection in surgical procedures and allow the surgeon to look through them and observe the tissues underneath. He can watch the condition of blood vessels and nervous tissues with an improved visibility that can help to avoid damage to delicate structures. Furthermore, as hidden structures such as small vessels come into view they are identified earlier. These instruments can also incorporate jeweled cutting edges and use their optical properties to improve further visualization of the surgical field.

Humans↗
PubMed1984

Clinical anaesthesia with isoflurane. A review of the multicentre study.

Following its approval for use in man, an unblinded, unrandomized epidemiological study of isoflurane anaesthesia was undertaken in the United States and Canada. The haemodynamic and reflex behaviour of 6798 patients were compared with their demographic characteristics and the anaesthetic drugs used. The decrease in arterial pressure and the increase in heart rate during isoflurane anaesthesia were confirmed. Intraoperative arrhythmias were most often associated with a history of similar arrhythmia before operation, as well as the occurrence of intraoperative hypertension. Airway reflexes were the predominant form of reflex activity identified, with coughing being the most frequently observed reflex. Serious complications were infrequent, and were unrelated to the use of isoflurane as the anaesthetic agent. The safety and efficacy of isoflurane anaesthesia in man was confirmed.

Adolescent↗
PubMed1983

Chiari malformation presenting in adults: a surgical experience in 127 cases.

We reviewed 127 patients who were operated upon for adult presentation Chiari malformation and made six conclusions: (a) The clinical examination remains crucial in the diagnosis. (b) The surgical anatomy is highly varied. (c) Syrinxes can be missed on preoperative contrast studies. (d) By a conservative grading system, we determined that 46% of the patients improved during long term follow-up. One-quarter deteriorated over the long run in spite of any treatment. (e) The overall results did not differ whether the treatment was plugging of the central canal plus decompression or decompression alone. (f) In patients with progression, plugging of the central canal obtained superior results. A review of the literature shows that the natural history of this complex disease process has not been established. This history is needed to identify the course of what may be several important factors that lead to the pathological condition in this disease.

Adolescent↗
PubMed1983

Evoked potentials from the motor tracts in humans.

Spinal cord monitoring during operation is of increasing importance in the prevention of injury. However, there is no direct monitor of the motor tracts available. We have reported a system using direct stimulation of the area overlying the motor tract between the intermediolateral sulcus and the dentate ligament in cats. This produces a 100-m/second signal with later components, which is abolished by section of the motor area, but not by section of the dorsal columns or the anterior quadrant of the spinal cord. Such stimulation also produces motor movement when the correct frequency is used. We now report the first application of this technique in humans, in whom we found the same 100-m/second signal, as well as slower components. We were able to elicit distal limb motor movement with stimulation of the motor tract area, but not with stimulation of the dorsal column area. This technique can be used either in open surgical cases or percutaneously and should provide an additional valuable technique for assessing spinal cord function.

Adult↗
PubMed1983

Simple plastic stereotactic unit for use in the computed tomographic scanner.

The marriage of computed tomography (CT) and stereotactic surgery offers an opportunity to provide sophisticated and effective treatment to discrete areas of the brain. An important part of this capability is the development of stereotactic frames that are compatible with the CT scanner, i.e., that do not degrade the CT image. A number of technically elegant and ingenious stereotactic frames have been reported. However, they have the drawback of technical complexity and, particularly, great exposure. We are reporting a simple ball and socket skull-mounted stereotactic device that allows solid fixation of probes for use in brain needle biopsies, ventricular catheterization, and similar activities.

Biopsy↗
PubMed1983

Primary malignant nerve sheath tumor of the gasserian ganglion: a report of two cases.

Primary tumors of the gasserian ganglion are usually benign, and secondary tumors are malignant. We report two cases of a malignant primary tumor of the gasserian ganglion, bringing the total in the world literature to five. The presentation, etiological features, and treatment of these cases are reviewed, together with a review of the literature. Preoperative differentiation from a benign tumor is not possible with certainty. A combination of operation and radiation therapy seems to be the best treatment at present.

Aged↗
PubMed1983

Spinal evoked potentials from the motor tracts.

There is a need to monitor the motor system, but it has a different blood supply and a different location in the spinal cord from those measured by traditional somatosensory evoked potential monitoring. This paper reports a motor evoked potential monitoring system that uses direct spinal cord stimulation overlying the areas of the motor tract in the cord. In nine cats, evoked potentials were recorded from the dura, which gave a much faster main signal component than the traditional dorsal column evoked potentials, which were also recorded. This 100-m/sec signal was not affected by sectioning of the dorsal columns, which was verified histologically. This mode of monitoring the motor system can be used during surgery. It may also provide a better evaluation of patients after spinal cord trauma.

Animals↗
PubMed1983

Septate bifrontal ependymal cyst. Case report.

The authors describe the case of a septate ependymal cyst involving both frontal lobes. The clinicopathological features, treatment, and results of previously reported cases are reviewed, and the etiology and pathogenesis of these cysts discussed.

Adult↗
PubMed1983

Laser-induced dorsal root entry zone lesions for pain control. Report of three cases.

Dorsal root entry zone lesions have been documented as effective for control of intractable pain in patients with brachial plexus avulsion or severe spinal cord injury. These lesions are usually made with the radiofrequency technique. The authors report three cases in which the CO2 laser was used as an alternative means of making the lesions. This latter technique provided effective pain relief in two of the patients and was efficient to use. It was noted that the presence of overlying scar tissue can be deceptive in judging the depth of the lesion made with the laser. The CO2 laser provided a means of producing controlled spinal cord lesions which may be more precise than the radiofrequency method.

Adult↗
PubMed1982

Recurrence of lumbar canal stenosis a decade after decompressive laminectomy.

Lumbar canal stenosis is treated by decompressive laminectomy with a high rate of success, but patients may experience late recurrence of pain. We report on 3 patients with return of symptoms years after their original decompression. CT scanning showed reformation by bone; their symptoms were relieved by decompression. While scarring is probably a more common cause of the return of pain, this reformation of bone can be more easily treated than scar formation and its presence should be sought by CT scanning.

Constriction, Pathologic↗
PubMed1982

Chronic cortical electrode array for seizure investigation.

Localization of seizure focus if surgical extirpation is contemplated is critical. It is routine to use cortical recording and stimulation for this purpose but the limited time available in the operating room limits what can be learned. We report a flexible electrode array of four 0.05 disc which can be banked to larger sizes, and left in place subdurally as well as epidurally. It can be used for stimulation as well as recording.

Adolescent↗
PubMed1982

Encouraging surgical results in walking patients with epidural metastases.

The management of epidural metastases is in a state of controversy between combined surgical and radiation treatment and treatment by radiation alone. Review of the literature shows that one group, patients who are ambulatory before treatment, have been studied rarely. We analyzed our last 15 years of experience at the Cleveland Clinic and found 39 patients who were ambulatory preoperatively; 84% of these walked during the short term follow-up and 93% of the 1-year survivors walked. These data suggest that surgery has an important role in the management of ambulatory patients.

Epidural Space↗
PubMed1982

Spinal cord meningioma.

The authors present a retrospective analysis of 97 cases of spinal meningioma. Age, sex, tumor location, and clinical presentation are similar to that reported by others. Importantly, even among paraplegic patients, one-third eventually walked. Other findings of note were poor results among those with calcified or recurrent tumors, and a high incidence of invasiveness among the rare epidural lesions. Males do not show the preference for a thoracic location that is found among females, and cervical tumors are almost all anterior to the cord. This last point suggests a different surgical approach in some cases. A large percentage of cases carried other diagnoses before tumor was recognized.

Adolescent↗