Failed back surgery syndrome: foreword.

The solution to the failed back syndrome will come from the surgeon who masters the technology, the pathology and the surgery and who understands the patient. The back is normally dynamic and the failed back is no longer dynamic. The multimodality approach has validity and requires attention to the brain as well as the local pain site. Neuro-augmentation is a variable but critical component of pain control. Welfare systems that promote disability may undermine successful therapy. Solutions to great problems usually come from men who are passionate, observing and skilful.

Advances in vertebral artery surgery at the skull base.

Between July 1975 and May 1985, 219 procedures were performed on the vertebral system; two were intracranial, 118 were at the skull base and 99 were at the neck base. Of the 108 patients operated on at the skull base, procedures were multiple in five and bilateral in two. Bypass to the vertebral artery between the transverse process of C1 and C2 was performed 91 times. The blood supply for the bypass was the common carotid (70), the external carotid (9), the internal carotid (9), the subclavian (3), and the occipital artery (3). Decompression was performed in three patients, segmental resection in seven, and ligation in two. The primary objective was to increase the flow capacity of the vertebral artery. This flow to the Circle of Willis supplies the forebrain and the hindbrain if the internal carotid artery is obstructed and the posterior communicating artery is patent, or it may supply only the hindbrain when no communication exists. The pathologic processes include atherosclerosis, thrombosis, dissection, compression, and vasospasm. The male:female ratio is 2:3. Long-term mortality is 19% for the male and 4.6% for the female. Hindbrain symptoms in the male predates cardiac symptoms by 2 to 4 years. Operative mortality and stroke rate is less than 3% combined. Long-term graft patency is 87%. Vertebral artery surgery at the skull base produces results superior to those following proximal segment reconstruction when measured by dynamic computerized tomographic scanning, neurofunctional testing, and symptom relief. Success following reconstruction depends on careful patient selection and surgical expertise. The techniques of reconstruction are well established and results have been durable for over a decade.

Absence of impaired glucose utilization in adipocytes from rats fed a carbohydrate-free, high protein diet.

Glucose utilization was studied in isolated adipocytes from rats fed a mixed (51% carbohydrate, 30% fat, 19% protein), high fat (81% fat, 19% protein) or high protein diet (30% fat, 70% protein). Despite similar food intake, rats on the high protein (HP) diet had smaller epididymal fat pads than the other two groups. The reduction in fat pad size was caused by small and variable reductions in both cell size and cell number. Fat cells from rats on the high fat (HF) diet had the previously reported reduction in pentose phosphate shunt activity in the absence and presence of insulin, and marked diminution of de novo fatty acid synthesis. Lactate release was elevated in the absence of insulin. There was no insulin stimulation of glucose uptake, CO2 production, glyceride-glycerol production or lactate release in these adipocytes. However, significant stimulation of fatty acid synthesis was seen. There was no impairment of glucose uptake or utilization in cells from rats on the HP diet despite the absence of dietary carbohydrate. Indeed, 14CO2 produced from glucose-l-14CO2 produced from glucose-1-14C was increased in these adipocytes. Thus the impaired glucose utilization in rats on the high fat, carbohydrate-free diet is due solely to the fat content of the diet.

Hypoglossal carotid entrapment syndrome.

Inflammation of the upper respiratory tract if frequently contiguous with the ICA and the HN in the neck. If severe, the inflammation of itself may occlude or directly extent into the ICA wall. The resulting scar produces a fixed relationship between artery and nerve that is vulnerable to lymph node enlargement, by head position, or blood pressure elevation. Trauma in the absence of scar may result in intimal injury of the ICA. Hypoglossal carotid entrapment may give rise to arterial stricture or diaphragm formation, microembolism, dissecting aneurysm, and arterial occlusion. Hypoglossal palsy with hemiatrophy of the tongue, unilateral headache, facial pain, or sympathetic disturbance of the upper face are less common than carotid or vertebral basilar symptoms. The diagnosis of HCE depends on understanding the pathological anatomy, hemodynamics, and mechanics of its production and aggravation. Patient history is important and close attention should be given to a history of tonsillitis, abscesses of the neck, unilateral headache, facial or orbital pain, and symptoms related to activity or elevation of blood pressure. The judicious use of noninvasive hemodynamic evaluation, EEG, neurotologic studies, CT scan, and CT dynamic scanning has been of value in diagnosis before surgery and in the documentation of hemodynamic benefit after surgery. Surgical reconstruction has been successful in the relief of ICA obstruction due to HCE and of associated symptoms and disability.

Cerebral hemodynamics evaluation.

The cerebral hemodynamic evaluation is the embodiment of a system approach to the hemodynamic factors that affect brain blood flow. The stresses employed are those encountered in everyday living. The instruments are simple and the method is basic. The importance of the cardiovascular response to the upright position and of brain perfusion to head motion deserves close attention in the clinical setting. The CHE complements the angiogram, the CT scan, and CT-rBBC studies by addressing the system and arterial hemodynamic factors affecting brain circulation. The CT-rBBC studies have given greater validity and direction to noninvasive and electrophysiologic testing because the ultimate concern is brain perfusion and function and not the angiogram. This combination of techniques has defined the role of the dynamic arterial obstruction and the vertebral artery in the hemodynamics of the brain. The cerebral hemodynamic evaluation is an integral part of the physiologic approach to the diagnosis and treatment of brain ischemia.

Pacemakers, cardiac mapping and EEG in the community hospital: a concise review of background and basic technical considerations.

The heart is a pump. The objective of cardiac pacing is to improve the cardiac output. The most popular method of cardiac pacing (RV) is not physiologic and results in reduced stroke output when compared to that of normal sinus or atrial paced rhythm. Recognition of pacemaker induced low output states and pacemaker aggravated neurological symptoms has quickened interest in physiologic atrial pacing. The increased complexity of atrial pacing has been discouraging in the past, but technical advances in electrode and pacemaker design are promising. Selection of the optimal pacing site appears critical and requires the determination of the focal electrical potential and stimulating threshold before electrodes are positioned. With minimal expense, the EEG can be adapted for this type of cardiac mapping in the community hospital.