Issam A. Awad and Gene H. Barnett
✓ The mechanism of nonhemorrhagic neurological deterioration from spinal arteriovenous malformation (AVM) and the role of acute surgical intervention in this setting are not well understood. The case is described of a 65-year-old man who presented with a 2-year history of mild gait spasticity and vague sensory complaints affecting both lower extremities. Following a diagnostic lumbar puncture, these symptoms progressed painlessly over a 4-day period to total motor paraplegia, urinary retention, and hypesthesia in all modalities with a midthoracic sensory level. Magnetic resonance imaging showed a probable spinal AVM but no evidence of hemorrhage or cord compression. Spinal angiography confirmed the diagnosis of spinal AVM fed by radicular branches of left T-7 and T-8 segmental intercostal arteries. Drainage was via long dorsal veins caudally. Emergency laminectomy with intradural exploration was performed. There was no evidence of prior hemorrhage or focal mass effect, although the cerebrospinal fluid pressure was elevated. The dural component of the spinal AVM was excised, and its communications with the spinal cord were disconnected intradurally. Neurological function started improving within 6 hours of the patient awakening from anesthesia. He had achieved antigravity strength in every muscle group of the lower extremities by the time of discharge to a rehabilitation center 10 days after surgery. Three months postoperatively, he was ambulating with a walker and was continent of urine and stool. Possible pathophysiological mechanisms are discussed in light of the favorable response to timely surgical intervention.
Gene H. Barnett, Allan H. Ropper and Keith A. Johnson
✓ Magnetic resonance (MR) imaging has been largely restricted to patients who are neurologically and hemodynamically stable. The strong magnetic field and radiofrequency transmissions involved in acquiring images are potential sources of interference with monitoring equipment. A method of support and physiological monitoring of critically ill neurosurgical and neurological patients during MR imaging using a 0.6-tesla MR system is reported. This technique has not caused degradation of the MR image due to electrical interference. Adequate preparation and precautions allow many critically ill neurosurgical and neurological patients to safely undergo MR imaging.
Symeon Missios, Kimon Bekelis and Gene H. Barnett
Laser interstitial thermal therapy (LITT) is a minimally invasive technique for treating intracranial tumors, originally introduced in 1983. Its use in neurosurgical procedures was historically limited by early technical difficulties related to the monitoring and control of the extent of thermal damage. The development of magnetic resonance thermography and its application to LITT have allowed for real-time thermal imaging and feedback control during laser energy delivery, allowing for precise and accurate provision of tissue hyperthermia. Improvements in laser probe design, surgical stereotactic targeting hardware, and computer monitoring software have accelerated acceptance and clinical utilization of LITT as a neurosurgical treatment alternative. Current commercially available LITT systems have been used for the treatment of neurosurgical soft-tissue lesions, including difficult to access brain tumors, malignant gliomas, and radiosurgery-resistant metastases, as well as for the ablation of such lesions as epileptogenic foci and radiation necrosis. In this review, the authors aim to critically analyze the literature to describe the advent of LITT as a neurosurgical, laser excision tool, including its development, use, indications, and efficacy as it relates to neurosurgical applications.
Gene H. Barnett, Allan H. Ropper and June Romeo
✓ The relationship between intracranial pressure (ICP) and outcome was studied in 10 adults with encephalitis. Eight had biopsy-proven herpes simplex encephalitis, one had acute hemorrhagic leukoencephalitis, and in one case the cause of encephalitis was unknown. Monitoring of ICP was instituted because of clinical deterioration or computerized tomography evidence of brain swelling, and was begun a mean of 7 days after the orlset of symptoms and continued for a mean of 9 days.
All five survivors, but only one of the five fatalities, had an initial ICP of less than 12 mm Hg (p < 0.05). Four patients with a mean daily ICP of less than 20 mm Hg survived, whereas five of six patients with higher ICP's died (p < 0.05). Peak ICP did not occur until the 12th day of illness on average. The Glasgow Coma Scale score at the time the ICP monitor was inserted did not correlate with outcome. Intracranial pressure monitoring in severe encephalitis may be a useful adjunct for therapy and an indicator of prognosis.
Gene H. Barnett, Andrew E. Sloan and Claudio E. Tatsui
Laser ablation (also known as laser interstitial thermal therapy [LITT]) has emerged as an important new technology for treating various disorders of the brain and spine. As with any new or emerging technology, there is a learning curve for its optimal use, and video tutorials can be important learning tools to help bridge gaps in knowledge for those who wish to become more familiar with laser ablation. In this special supplement to Neurosurgical Focus, videos illustrate laser ablation’s use in the treatment of epilepsy and failed radiosurgery, as well as technical aspects of performing these procedures in eloquent brain and in the spine. We hope that these videos will enable you to enhance your understanding of the evolving use of laser ablation for disorders of the brain or spine. It is the editors’ sincere hope that this will be helpful either in your own practice or in determining whether to refer to a neurosurgical colleague experienced in this field.
Report of three patients
Marc I. Chimowitz, Gene H. Barnett and Joann Palmer
✓ Of 165 consecutive patients undergoing computerized tomography- or magnetic resonance imaging-guided stereotactic brain biopsies at the Cleveland Clinic between June, 1987, and November, 1989, four patients (2.4%) developed arterial hemorrhage refractory to conventional efforts to secure hemostasis. Craniotomy was performed in one of these patients to control the hemorrhage; in the other three, 0.5 to 2 cc of thrombin (5000 U/cc) was slowly injected via the biopsy cannula, resulting in immediate control of bleeding in all three cases. Postoperatively, the first two patients treated with 1 to 2 cc of thrombin were slow to awaken; one had evidence of vasospasm by transcranial Doppler ultrasound studies and multiple infarcts on cranial computerized tomography, while the other had a moderate-sized frontal hematoma with intracranial hypertension. After prolonged recovery periods, only mild neurological deficits persisted in both patients. The third patient, treated with 0.5 cc of thrombin, had an uneventful postoperative course. Thrombin is highly effective for stopping intractable arterial hemorrhage during stereotactic brain biopsy; however, it is a vasospastic agent and may have been responsible for the cerebral infarctions in one patient. Therefore, thrombin should be used only as a last resort, short of craniotomy, to control intractable arterial hemorrhage during stereotactic brain biopsy.
Sarel J. Vorster and Gene H. Barnett
Although surgical resection of brain tumors has been performed for over a century, complications still occur with distressing frequency.
The authors propose a simple preoperative grading scheme to assess surgical risk for resection of primary and secondary intraaxial supratentorial brain tumors.
The authors retrospectively reviewed the clinical records, neuroimaging studies, and outcomes of 224 surgeries performed in 207 patients from January 1993 to December 1995 at the Cleveland Clinic Foundation Brain Tumor Center. Subsequently, they considered and statistically analyzed multiple variables related to the patients and their lesions. Surgical risk was defined as any complication occurring within 30 days postoperatively, and was divided into transient operative complications, transient medical complications, and new sustained neurological deficits. Length of stay was also recorded. The overall incidence of complications was 10.6% and the mortality rate was 2.7%, with a median hospital stay of 3 days. Patient age greater than 60 years (p < 0.001), preoperative Karnofsky Performance Scale scores of 50 or less (p < 0.03), previous irradiation (p < 0.001), tumor location in eloquent regions (p < 0.03), and depth of tumor invasion (p < 0.001) independently predicted complicated outcome or increased length of stay. Finally, the authors derived a simple five-tier grading scheme in which these patient risk factors are added together to obtain a grade of I to V that corresponds to outcome and length of hospital stay.
This grading scheme may be used to identify patients at higher risk and facilitate comparison of results between institutions and individual surgeons.
Narendra Nathoo, Marc R. Mayberg and Gene H. Barnett
✓ W. James Gardner, a skillful neurosurgeon and inventor, is best remembered for his cervical tongs and hydrodynamic theory of syringomyelia.
A pioneer of modern neurosurgery, Gardner trained under Charles Frazier in Philadelphia, and in 1929 he moved to Ohio where he became chief of neurosurgery at the Cleveland Clinic, a position he was to hold for the next 33 years. A large surgical practice made it imperative for Gardner to develop surgical methods that were quick, effective, and advantageous for patient and surgeon. He was an early proponent of the sitting position for patients undergoing cranial surgery, which led to the development of a neurosurgical chair with a head fixation device. To reduce the risks of hypotension and air embolism when the patient is in the sitting position, Gardner invented the clinical G suit. He was the first to advocate and use induced arterial hypotension for intracranial surgery and the first neurosurgeon in the US to publish his experiences performing lumbar discography. He converted an operating table so that he could induce hypothermia during aneurysm surgery and then applied pneumatic cuffs to occlude the major arterial supply to the brain. His pioneering work has been documented in many other areas such as hemifacial spasm and trigeminal neuralgia, for which he performed the first vascular decompression, in cervical sympathectomy for treatment of various ailments, and in the use of intrathecally delivered steroid drugs for sciatica. During his career, he authored 256 publications and one book on the dysraphic states. Many of his contributions to the discipline of neurosurgery are now taken for granted.
Case report and review of the literature
Richard A. Prayson, James T. McMahon and Gene H. Barnett
✓ The authors present the case of a left frontal solitary fibrous tumor of the meninges. The gross appearance of the tumor was very similar to that of a fibroblastic meningioma. Histological examination showed a mixture of spindle-shaped and round cells arranged in a collagen matrix. Immunohistochemical staining of the tumor demonstrated diffuse positive staining for CD34 and vimentin. The tumor displayed no positive staining for markers of muscle, epithelial, glial, or neurocrest differentiation or for estrogen and progesterone receptors. The MIB-1 labeling index (the percentage of positive staining tumor cell nuclei), a marker of cellular proliferation, was 1.1%. Ultrastructural studies support attributing a mesenchymal, rather than meningothelial, nature to the tumor. A differential diagnosis is discussed and a review of the literature on these rare tumors is presented.