Ricardo Segal

Neurogenic hypertension: etiology and surgical treatment. I. Observations in 53 patients.

Although an extensive literature exists concerning essential arterial hypertension, the primary etiology has been unclear. Arterial compression of the left lateral medulla oblongata by looping arteries of the base of the brain was seen incidently in 51 of 53 hypertensive patients who underwent left retromastoid craniectomy and microvascular decompression for unrelated cranial nerve dysfunctions. Such compression was not noted in normotensive patients. Treatment by vascular decompression of the medulla was performed in 42 of the 53 patients. Relief in the hypertension was seen in 32 of the patients and improvement in four. Arteriosclerosis and arterial ectasia contribute to arterial elongation and looping. If pulsatile compression of the left lateral medulla occurs, hypertension may develop as a consequence of an imbalance in the neural control systems that normally regulate blood pressure. The hypertension may further contribute to arterial elongation, providing a vicious circle of pathophysiologic changes.

Subarachnoid hemorrhage and the heart.

&NA; Electrocardiographic abnormalities, both morphological and rhythmic, are frequently seen in association with spontaneous subarachnoid hemorrhage. These changes, which often reflect subendocardial damage, seem to be caused by hypothalamic stimulation leading to an acute increase in sympathetic tone. As a result, potentially life‐threatening ventricular arrhythmias may develop in subarachnoid hemorrhage patients. These arrhythmias have responded to sympathetic blocking agents, which may also have a protective effect on subendocardial tissue in this setting. There is no evidence that the prophylactic administration of propranolol or other autonomic blockers significantly alters outcome in these patients. Ultimate morbidity and mortality are clearly related to the degree of intracerebral‐intraventricular hemorrhage and vasospasm. This article reviews experimental and clinical evidence regarding the causes of cardiac abnormalities after subarachnoid hemorrhage, the types of abnormalities most frequently seen, their relationship with subendocardial lesions, and the role of autonomic blockers. (Neurosurgery 18:101‐106, 1986)

Neurogenic Hypertension: Etiology and Surgical Treatment, Ii. Observations in an Experimental Nonhuman Primate Model

In a companion paper (Ann Surg 1985; 201(3):391-398), clinical data which suggest that neurogenic hypertension may be caused by arterial compression of the left medulla oblongata was presented. A chronic pathophysiologic animal model of neurogenic hypertension using a substitute for arterial pulsation, the neurovascular compression simulator (NCS), was developed. This paper presents data that demonstrate how development of hypertension in a nonhuman primate baboon (5 subject animals, 5 control animals) can be caused by the NCS, and the blood pressure can subsequently return to normal following cessation of NCS activity. These experiments show that pulsatile compression of the left ventrolateral medulla oblongata results in cardiovascular changes consistent with the sequence found in human neurogenic hypertension. Arteriosclerosis and arterial ectasia in the human contribute to arterial elongation and looping at the base of the brain. An arterial loop, by causing pulsatile compression of neural structures, elicits an increase in blood pressure initiated by an increase in cardiac output. This may be due to interference with the autonomic control of the heart and/or by alteration of the relative capacitance of the vascular system.

Median nerve injury from local steroid injection in carpal tunnel syndrome.

Local steroid injections for symptomatic relief of carpal tunnel syndrome have become common in the evaluation and treatment of this disorder; yet reports of median nerve injection injury from this practice are rare. We present a case of nerve injury from a steroid injection in a 24-year-old man with carpal tunnel syndrome that was successfully treated by division of the transverse carpal ligament and neurolysis. The histopathological characteristics of the lesion are presented, and the pathogenesis and treatment of this injury are discussed. Means of avoiding this complication include careful attention to anatomic landmarks as well as to the patients subjective response during injection and avoidance of the use of local anesthetics.

Intracranial Clips: An Examination of the Devices Used for Aneurysm Surgery

A properly functioning aneurysm clip is of paramount importance in the surgical ablation of intracranial aneurysms. An appropriate match between the closing force needed to ablate an aneurysm and the force exerted by the aneurysm clip must be achieved. In this study, the opening and closing forces exerted by several commonly used aneurysm clips were tested. There was a strong correlation between the classification of the clips, according to the Dujovny system, and their mechanical behavior. Minimal variability among different lots of the same clip type and minimal hysteresis were generally exhibited by the alpha mobile fulcrum class clips, such as the Yasargil, Vari-Angle McFadden, Scoville, and Mayfield clips. Significant exceptions included several types of Mayfield and Drake clips. In contrast, pivot class clips generally showed twice as much lot variability among different lots, as well as a significant amount of hysteresis. Clips of this class include the Vari-Angle, Heifetz, and Pivot clips. Because significant variations in clip force exist and because several other factors can compound these differences, it is suggested that aneurysm clips be individually tested for their closing forces before they are used in an operation.

Fibrous dysplasia in combination with aneurysmal bone cyst of the occipital bone and the clivus: case report and review of the literature.

OBJECTIVE AND IMPORTANCE Fibrous dysplasia of the cranium is a relatively uncommon disorder that affects primarily the anterior cranial region; its occurrence in the cranial base in combination with aneurysmal bone cyst (ABC) constitutes an extremely rare condition, only two cases of which have been reported previously in the literature. It is important to recognize and treat these cases properly because of the special location in the cranial base and the possibility of neural structure impingement. CLINICAL PRESENTATION We report the case of a 19-year-old man with a slowly enlarging mass of the occiput, with computed tomographic and magnetic resonance imaging revealing involvement of petrous and basisphenoid bone and growing ABC. INTERVENTION Open biopsy confirmed the diagnosis of fibrous dysplasia. Partial excision of the lesion and removal of the ABC were performed in a second stage after embolization. CONCLUSION ABC associated with fibrous dysplasia of the cranial base may enlarge rapidly after puberty and require excision. This is facilitated by preoperative embolization.

Spinal subdural hematoma associated with anticoagulant therapy in a patient with spinal meningioma.

A case of spontaneous subdural hematoma in the cervicothoracic region associated with a small meningioma in a patient on anticoagulant therapy is presented. The neurological complications of anticoagulant therapy are discussed briefly. Progressive neurological deterioration in a patient on anticoagulant therapy should prompt the performance of an emergency myelogram and a possible laminectomy in spite of the potential risks of these procedures. Intraspinal bleeding occurs more frequently in the form of an epidural hematoma, but the clinical presentation may not allow differentiation from a subdural hematoma. The possible causal relation between the asymptomatic spinal meningioma, the anticoagulant therapy, and the formation of the subdural hematoma is discussed.

Spinal cord stimulation, conception, pregnancy, and labor: case study in a complex regional pain syndrome patient.

Introduction. Interventional modalities for pain treatment are reserved for patients failing multidisciplinary pain management, including psychological, physical, pharmacological, and anesthetic techniques.

Communicating Hydrocephalus Secondary to Diffuse Meningeal Spread of Wegener's Granulomatosis: Case Report and Literature Review

OBJECTIVE AND IMPORTANCE We present a very unusual case of diffuse spread of Wegeners granulomatosis causing hydrocephalus. CLINICAL PRESENTATION A 53-year-old man presented in 1985 with bilateral middle ear infections requiring myringotomies. During the next 18 months, he went on to develop a left Bells palsy. The patient then began to develop recurrent occipital headaches along with left sixth and seventh nerve palsies and a green nasal discharge requiring hospitalization. Workup included magnetic resonance imaging showing pronounced enhancement of the tentorium and meninges in the occipital region with normal ventricle size. An x-ray of the chest showed multiple pulmonary nodules. A regimen of prednisone and cyclophosphamide was initiated. The patient did well for 2 years until he again developed middle ear infections and headache. Serial lumbar punctures showed increased pressures. A circulating antineutrophil cytoplasmic antibody was positive. Cyclophosphamide was administered, with acetazolamide added for treatment of the elevated intracranial pressure. The patient stabilized for another 2 years but then presented in 1994 with recurrent headache, bilateral papilledema, and mild left arm and right leg weakness. A lumbar puncture was performed with an opening pressure of 52 cm H2O. Computed tomography of the head revealed moderate enlargement of the lateral third and fourth ventricles, consistent with communicating hydrocephalus. INTERVENTION A right frontal ventriculoperitoneal shunt was placed. A leptomeningeal biopsy performed at the side of catheter placement (far away from any meningeal enhancement revealed by magnetic resonance imaging) showed chronic meningitis and multinucleated giant cells. Cyclophosphamide therapy was begun again. The patient has not experienced recurrence of headache, cranial nerve deficits, or papilledema for more than 3 years. CONCLUSION This is the first reported case of diffuse involvement of the meninges from Wegeners granulomatosis. Fortunately, this patient responded well to shunting and sustained medical management. Although rare, Wegeners granulomatosis should be included in the differential diagnosis of chronic aseptic meningitis, communicating hydrocephalus, and papilledema.

Hemodynamic Changes Induced by Pulsatile Compression of the Ventrolateral Medulla

From the Department of Neurological Surgery, University of Pittsburgh School of Medicine, and the Veterans Administration Medical Center, Pittsburgh, Pennsylvania. Supported by grants from the WPHA, the Pittsburgh Foundation, The Sarah Scaife Foundation, Walter L. Copeland Foundation, and the University of Pittsburgh Medical School Alumni Association and by a Mary George grant and NIH grant. Presented at the 27th Annual Meeting of the American College of Angiology, San Diego, California, November 5-9, 1980. Introduction