Surgery for metastatic spine tumors in the elderly. Advanced age is not a contraindication to surgery!

BACKGROUND: With recent advances in oncologic treatments, there has been an increase in patient survival rates and concurrently an increase in the number of incidence of symptomatic spinal metastases. Because elderly patients are a substantial part of the oncology population, their types of treatment as well as the possible impact their treatment will have on healthcare resources need to be further examined. PURPOSE: We studied whether age has a significant influence on quality of life and survival in surgical interventions for spinal metastases. STUDY DESIGN: We used data from a multicenter prospective study by the Global Spine Tumor Study Group (GSTSG). This GSTSG study involved 1,266 patients who were admitted for surgical treatments of symptomatic spinal metastases at 22 spinal centers from different countries and followed up for 2 years after surgery. PATIENT SAMPLE: There were 1,266 patients recruited between March 2001 and October 2014. OUTCOME MEASURES: Patient demographics were collected along with outcome measures, including European Quality of Life-5 Dimensions (EQ-5D), neurologic functions, complications, and survival rates. METHODS: We realized a multicenter prospective study of 1,266 patients admitted for surgical treatment of symptomatic spinal metastases. They were divided and studied into three different age groups: <70, 70-80, and >80 years. RESULTS: Despite a lack of statistical difference in American Society of Anesthesiologists (ASA) score, Frankel neurologic score, or Karnofsky functional score at presentation, patients >80 years were more likely to undergo emergency surgery and palliative procedures compared with younger patients. Postoperative complications were more common in the oldest age group (33.3% in the >80, 23.9% in the 70-80, and 17.9% for patients <70 years, p=.004). EQ-5D improved in all groups, but survival expectancy was significantly longer in patients <70 years old (p=.02). Furthermore, neurologic recovery after surgery was lower in patients >80 years old. CONCLUSIONS: Surgeons should not be biased against operating elderly patients. Although survival rates and neurologic improvements in the elderly patients are lower than for younger patients, operating the elderly is compounded by the fact that they undergo more emergency and palliative procedures, despite good ASA scores and functional status. Age in itself should not be a determinant of whether to operate or not, and operations should not be avoided in the elderly when indicated.

Paroxysmal raised intracranial pressure associated with spinal meningeal cysts.

Raised intracranial pressure in association with spinal meningeal cysts has rarely been reported. We describe four patients in whom evidence of paroxysmal raised intracranial pressure was found in association with spinal meningeal cysts. Cerebrospinal fluid diversion procedures have previously been shown to relieve local symptoms due to spinal cysts. In our patients symptoms of paroxysmal headache were alleviated by this method, suggesting a causal relationship with the raised pressure. This association may be an under diagnosed cause of paroxysmal headaches. We review the medical literature on the classification of spinal meningeal cysts, evaluate the theories of their origin and offer suggestions on the pathogenesis of the abnormal CSF dynamics that may allow an interplay between raised intracranial pressure and spinal meningeal cysts to produce paroxysmal symptoms.

Quantitative measurement of cerebral blood flow and cerebral blood volume after cerebral ischaemia.

CBF obtained by the hydrogen clearance technique and cerebral blood volume (CBV) calculated from the [14C]dextran space were measured in three groups of rats subjected to temporary four-vessel occlusion to produce 15 min of ischaemia, followed by 60 min of reperfusion. In the control animals, mean CBF was 93 +/- 6 ml 100 g-1 min-1, which fell to 5.5 +/- 0.5 ml 100 g-1 min-1 during ischaemia. There was a marked early postischaemic hyperaemia (262 +/- 18 ml 100 g-1 min-1), but 1 h after the onset of ischaemia, there was a significant hypoperfusion (51 +/- 3 ml 100 g-1 min-1). Mean cortical dextran space was 1.58 +/- 0.09 ml 100 g-1 prior to ischaemia. Early in reperfusion there was a significant increase in CBV (1.85 +/- 0.24 ml 100 g-1) with a decrease during the period of hypoperfusion (1.33 +/- 0.03 ml 100 g-1). Therefore, following a period of temporary ischaemia, there are commensurate changes in CBF and CBV, and alterations in the permeability-surface area product at this time may be due to variations in surface area and not necessarily permeability.

Transient blood-brain barrier permeability following profound temporary global ischaemia: an experimental study using 14C-AIB.

The influence of reperfusion after profound incomplete forebrain ischaemia on blood-brain barrier (BBB) permeability to a small protein tracer was studied in male Sprague-Dawley rats. The mean cortical blood to brain transfer constant (Ki) for 14C-amino isobutyric acid (AIB) was significantly greater at 3 and 6 h of reperfusion, 2.5 times the mean values of controls (p less than 0.05) (2.5 microliter g-1 min-1 and 1.0 microliters g-1 min-1 respectively), but had returned to control values after reperfusion for 24 h. Analysis of distribution of Ki values showed that following 15 min and 30 min of profound ischaemia, there was a significant increase in transfer of AIB across the blood-brain barrier (BBB) after recirculation for up to 6 h, though there was no evidence of protein extravasation as assessed by Evans Blue (EB) dye. After 24 h of reperfusion, the BBB to AIB was restored, and Ki values had returned to control values. It is concluded that following transient global ischaemia, the BBB may recover rapidly.

Regional blood-brain barrier permeability changes after restoration of blood flow in postischemic gerbil brains: a quantitative study.

A quantitative technique utilising [14C]alpha-aminoisobutyric acid as a tracer was used to study cerebrovascular permeability in 22 Mongolian gerbils. Seven other animals were used to measure cerebral blood volumes. Global cerebral ischaemia was produced by temporary bilateral carotid artery occlusion (60 min) in 16 gerbils that were sacrificed at 1, 2, and 3 h following reperfusion. The blood-to-brain transfer constant was significantly increased after 2 h of reperfusion in the ischaemic zones and also in structures, like the cerebellum, not supplied by the carotid artery and not ischaemic during the vessel occlusion. The blood-brain barrier (BBB) alterations were coincident with the onset of ischaemia--induced seizures that were accompanied by sudden "spikes" of systemic blood pressure. Epilepsy may play an important role in the development of BBB damage in this ischaemic model, and this factor must be considered in the interpretation of BBB damage data in gerbils.

19F imaging of cerebral blood oxygenation in experimental middle cerebral artery occlusion: preliminary results.

Fluorine (19F) nuclear magnetic resonance may be used to image cerebral perfusion in cats receiving perfluorocarbon blood substitutes. 19F relaxation times in these blood substitutes are dependent on oxygen tension (PO2) and may be used to calculate and spatially map cerebrovascular PO2 values in vivo. We have applied this noninvasive method to experimental middle cerebral artery (MCA) occlusion. Following MCA occlusion a perfusion defect is evident in the sylvian region, followed by the appearance of collaterals. Signal from the ipsilateral rete mirabilis is increased. Calculated cortical vascular PO2 values indicate a relative reduction in oxygenation in the ischaemic hemisphere. PO2 maps show a perfused hypoxaemic zone adjacent to the perfusion defect. These changes are partly reversed with reperfusion.

Acute cerebral ischaemia: concurrent changes in cerebral blood flow, energy metabolites, pH, and lactate measured with hydrogen clearance and 31P and 1H nuclear magnetic resonance spectroscopy. I. Methodology.

CBF has been measured with the hydrogen clearance technique in the two cerebral hemispheres of the gerbil under halothane anaesthesia. This has been correlated with changes in local pH, tissue lactate, and phosphorus energy metabolites measured in the same animals with 1H and 31P nuclear magnetic resonance (NMR) spectroscopy. The NMR measurements were made with two surface coils, one on each hemisphere. This article describes the experimental details and shows that in acute unilateral or bilateral forebrain ischaemia metabolic changes can be monitored by NMR with no significant interhemispheric cross talk. The metabolic effects of reperfusion are also shown. The model allows the definition of the time course of the metabolic consequences of regional ischaemia and reperfusion in individual laboratory animals.

Acute cerebral ischaemia: concurrent changes in cerebral blood flow, energy metabolites, pH, and lactate measured with hydrogen clearance and 31P and 1H nuclear magnetic resonance spectroscopy. II. Changes during ischaemia.

CBF has been measured with the hydrogen clearance technique in the two cerebral hemispheres of the gerbil under halothane anesthesia. This has been correlated with changes in local pH, tissue lactate, and phosphorus energy metabolites measured in the same animals with 1H and 31P nuclear magnetic resonance spectroscopy. We demonstrate a threshold flow value for the metabolic changes associated with energy failure at a level similar to the values previously reported for electrical failure and tissue water accumulation, but higher than that associated with breakdown of extracellular potassium homeostasis.

Acute cerebral ischaemia: concurrent changes in cerebral blood flow, energy metabolites, pH, and lactate measured with hydrogen clearance and 31P and 1H nuclear magnetic resonance spectroscopy. III. Changes following ischaemia.

CBF has been measured with the hydrogen clearance technique in the two cerebral hemispheres of the gerbil under halothane anaesthesia. At the same time, intracellular pH and the concentrations of lactate and high-energy phosphates were measured in the brain using 1H and 31P nuclear magnetic resonance spectroscopy. Flow and metabolism have been followed during either a 15- or a 30-min ischaemic period (induced by bilateral carotid occlusion) and for up to 1 h of recovery. There was no significant difference between the flow characteristics of the two experimental groups. High-energy phosphate levels and pH returned to control within approximately 20 min of the end of the ischaemic period. Lactate clearance, following a 30-min occlusion, was slower than the recovery of pH. The concentration of free ADP, calculated from the creatine kinase equilibrium, was lower during the recovery phase than under control conditions.

Three cases of craniopharyngioma showing optic tract hypersignal on MRI.

Three patients presenting with visual failure had MRIs with hypersignal extending from the region of the optic chiasm along both optic tracts in 2 cases, and along 1 optic tract in the 3rd. In all patients intrinsic tumor of the chiasm was the most likely diagnosis based on MRI appearances, but all 3 had craniopharyngioma.

The significance of pulmonary changes associated with cerebral perfusion with hypoxic blood in monkeys.

Parameters of cerebral and pulmonary function were studied in ten animals whose brains were perfused with hypoxic right atrial blood according to the Moss method. All animals died as a result of cerebral hypoxia at about 95 minutes after the onset of perfusion. Gross pulmonary congestion, edema, and leukocyte plugs occurred in the seven animals breathing spontaneously, but positive pressure ventilation prevented these changes in three. The resumption of cerebral perfusion with oxygenated blood after 30 minutes of the Moss procedure did not prevent the pulmonary changes and, of more importance, did not prevent cerebral swelling and death at about the same time as that of all the other animals. There were no changes in oxygen uptake or in arterial oxygen tension to indicate that progressive pulmonary failure contributed to death. It is concluded that this model produces brain swelling and brain death with incidental pulmonary pathological changes indistinguishable from early findings in hemorrhagic shock models and that the cerebral hypoxic perfusion model in monkeys is not suitable for studying the effects of "shock lung" therapy.

5-HT-containing nerves to major cerebral arteries of the gerbil originate in the superior cervical ganglia.

This study has shown that over 95% of the 5-hydroxytryptamine (5-HT)-containing nerves to major cerebral arteries in the gerbil share a common origin with noradrenergic cerebrovascular nerves in the superior cervical ganglia. A small group of 5-HT-containing and noradrenergic nerves to the vessels of the posterior brain circulation had a different origin, which may be either central or peripheral. The pial blood vessels of the gerbil appeared to have no 5-HT-containing nerve supply. The effects of unilateral superior cervical ganglionectomy on 5-HT-containing and noradrenergic nerves to the arteries of the circle of Willis were different. Our results showed total loss of 5-HT-containing nerves on the vessels ipsilateral to the ganglionectomy combined with ca. 50% reductions of nerve density on the vessels of the contralateral side. There were no contralateral reductions of noradrenergic nerve density in parallel experiments although again the ipsilateral side was totally denervated. We suggest that 5-HT-containing cerebrovascular nerves are differently distributed as well as being in some way more sensitive to nerve damage compared to noradrenergic cerebrovascular nerves. The relationship between a combined serotonergic and noradrenergic vasoconstrictor control of large cerebral blood vessels and serotonergic vasodilation of small pial blood vessels is discussed.

Origin and postnatal development of nerves showing 5-hydroxytryptamine-like immunoreactivity supplying major cerebral arteries of the rat.

Nerve plexuses showing 5-hydroxytryptamine (5-HT)-like immunoreactivity (5-HTLI) have been demonstrated in all the major cerebral arteries of the rat using fluorescence immunohistochemistry on whole-mount stretch preparations. Following bilateral superior cervical ganglionectomy, nerves disappeared from all the vessels studied with the exception of the vertebral and basilar arteries where fibres remained. Using image analysis, the density of nerves containing 5-HTLI showed little change between vessels from 3 to 4-week-old and 6 to 7-week-old animals, in contrast to another study which has shown marked reductions in 5-HT-immunoreactive neuronal cell bodies in the superior cervical ganglion over the same period of early development. It was concluded that while the terminals of cerebrovascular nerves retain the capacity to synthesise and/or store 5-HT throughout life, their cell bodies may lose this function soon after birth.

Changes in regional cortical tissue oxygen tension and cerebral blood flow during temporary middle cerebral artery occlusion in baboons.

Cortical tissue oxygen measured by a platinum cathode, and cerebral blood flow recorded by a hydrogen clearance technique, were measured in 13 baboons before, during and after temporary occlusion of the middle cerebral artery. Mean control pO2 was 23.8 +/- 14 mm Hg and mean flow 51.3 +/- 12 ml/100g/min. During the occlusion, there was a gradation in pO2 from values in the opercular area of 3.6 +/- 5.9 mm Hg, to values in the high parietal area of 11.9 +/- 11.7, these being statistically different (P less than 0.05) from each other. The corresponding flow values were 5.5 +/- 7.5 (opercular) and 22.3 +/- 21.7 ml/100 g/min parietal (P less than 0.01). Following removal of the MCA clip, between 20% and 30% of the electrodes registered an early hyperoxia and hyperaemia, which lasted up to 5 min. A late and prolonged hyperoxia, with less evidence of hyperaemia, was also noted in about 20%. The mean tissue pO2, however, at 5-min intervals up to 40 min following the removal of the clip only reached 60-80% of control values in the most ischaemic areas. Only the parietal region showed a mean pO2 above control levels. The mean flow data were uniformly reduced in all regions to about 80% of control values. During and after a second occlusion in 6 animals, similar changes were noted but with even fewer instances of hyperoxia. The mean oxygen and flow results were lower than with the first occlusion, but the reduction was not significant. There was no overall effect of hypercapnia on cortical tissue pO2 during the control period, but there was a significant (P less than 0.05) reduction during the same procedure after the period of ischaemia. An increase in pO2 during hypercapnia could be observed if there were arousal responses of blood pressure "spikes".

Measurements of oxygen tension in the cerebral cortex of baboons.

A polystyrene-covered platinum electrode (100-150 mum diameter) has been used to measure cortical tissue oxygen tension in baboon brains. The method of preparation, calibration, and the importance of small residual current (less than 40 nA) as an attribute of a reliable electrode, are described. With electrodes of this size, there was a large (16 +/- 12nA/torr) and linear current output with pO2 changes. The effect of avrious gases in addition to oxygen is described; halothane inhalation increases the apparent pO2 and hydrogen, used for blood flow estimations, reduces the recorded pO2. In 48 separate electrode placements in 13 baboons, the mean cortical qo2 was 23.8 +/- 12 mm Hg, with a range from 1-79 mm Hg; following occlusion of one middle cerebral artery, 37 electrodes recorded a pO2 of less then 5 mm Hg pO2 Oscillations were invariably noted in control conditions, independent of blood pressure; these waves disappeared during MCA occlusion and appeared to be augmented following release of the clip. Blood pressure "spikes" produce immediate and synchronous changes in all electrodes entirely different from the spontaneous waves. Such blood pressure changes may mask the true effect of hypercapnia on tissue pO2 and, if ignored, may lead to erroneous assumptions regarding local neural control of the circulation, the increased pO2 secondary to hypertension being regarded as evidence of regional vasodilation. A SUdden change in inspired pO2-the "air test"-was performed in control conditions and following the ischaemic insult, and the rate of change of cortical pO2 compared. The gradient was significantly greater (P less than 0.05) following ischaemia, suggesting a changed ratio in the tissue's flow to oxygen requirements and/or a persisting vasodilatation.

Cerebral perivascular serotonergic fibres have a peripheral origin in the gerbil.

The origin of serotonergic nerves supplying the large cerebral vessels of the gerbil has been investigated after bilateral superior cervical ganglionectomy. Immunohistochemical techniques were applied to whole-mount stretch preparations of the cerebral vessels. Removal of both ganglia resulted in the complete loss of immunoreactive fibres in the vessels supplied by the internal carotid artery and in a marked reduction of fibres innervating vessels of the vertebro-basilar system, indicating that most of the cerebrovascular serotonergic nerves have a peripheral sympathetic origin in the gerbil. The contrast with the central origin of serotonergic perivascular nerves claimed in the rat is discussed.

The transoral approach for the management of intradural lesions at the craniovertebral junction: review of 7 cases.

The main difficulty in dealing with intradural lesions located ventrally in the region of the craniovertebral junction (CVJ) is related to their relative inaccessibility. Posterolateral approaches involve some manipulation of the brain stem and provide limited access because of the necessity of working between the cranial nerves. Even then, the view of the ventral midline and across is limited. The transoral approach, which has been widely used for the management of extradural lesions in this area, is also useful for the treatment of intradural lesions. It provides an unimpeded although somewhat restricted, view of the ventral aspect of the CVJ without the need for brain retraction. The cranial nerves and vertebral arteries are not interposed between the surgeon and the lesion. The risks of cerebrospinal fluid leakage and infection are greatly diminished by the use of fibrin adhesive and prolonged diversion of the cerebrospinal fluid. The use of this approach, together with its technical difficulties and results, in the management of seven purely intradural lesions located ventrally at the CVJ, is discussed.

Surgical access to the base of skull and upper cervical spine by extended maxillotomy.

An extended maxillotomy has been developed to permit wider surgical access to the base of the skull. It has proven particularly useful in the management of the previously untreatable neuraxial compression caused by basilar invagination in cases of osteogenesis imperfecta. In addition, patients with extensive extradural space-occupying lesions have been treated. The surgical technique is described and the results of its use in nine patients are presented.

Transoral transclival removal of anteriorly placed meningiomas at the foramen magnum.

Anteriorly placed meningiomas at the level of the foramen magnum are rare, are difficult to diagnose, and present technical problems for a conventional posterior fossa removal. The authors describe the successful transoral transclival excision of two such tumors. Cerebrospinal fluid (CSF) fistula can be avoided by dural repair using a thrombin glue and long term CSF diversion. This modification enables the transoral route to be considered for anteriorly placed intradural lesions.

Primary rhabdomyosarcoma of the central nervous system: case report.

A case of a primary rhabdomyosarcoma that appeared to be arising from the filum terminale in a 48-year-old man is reported. The histological diagnosis of rhabdomyosarcoma was supported using immunocytochemical methods. Twenty-two cases of primary rhabdomyosarcoma of the central nervous system previously reported in the literature are reviewed briefly. The possible origin of these tumors from neuroectoderm is discussed.