Soft cervical disc herniation. Influence of cervical spinal canal measurements on development of neurologic symptoms.

STUDY DESIGN: In 100 consecutive patients who underwent surgery because of soft cervical disc herniation, the sagittal and transverse diameters, the area of the bony cervical spinal canal, the sagittal diameter of the hernia, and the minimal bony intervertebral foramen diameter were measured by computed tomography. The data were compared with measurements from a control group of 35 matched healthy individuals. OBJECTIVES: To evaluate the relation between the severity of concurrent neurologic symptoms and the sagittal and transverse diameters, the cross-sectional area of the bony spinal canal, the sagittal diameter of the hernia, and diameter of the minimal bony intervertebral foramen in patients with soft cervical disc herniation. SUMMARY OF BACKGROUND DATA: Traumatic injury and spondylotic changes have a far greater impact on the spinal cord and nerve roots if the sagittal diameter of the bony cervical spinal canal is small. However, in the case of soft cervical disc herniation, no computer tomographic measurements are available for sagittal and transverse diameters, cross-sectional area of the bony spinal canal, sagittal diameter of the hernia, and diameter of the minimal bony intervertebral foramen in relation to the severity of concurrent neurologic symptoms. METHODS: Computed tomography was used to measure sagittal and transverse diameters, cross-sectional area of the bony cervical spinal canal, sagittal diameter of the hernia, and diameter of the minimal bony intervertebral foramen in 100 patients with symptomatic monosegmental cervical soft disc herniation. All patients had undergone an anterior discectomy with removal of the hernia and subsequent interbody fusion using an autologous bone graft taken from the iliac crest. RESULTS: A mean sagittal diameter of the bony cervical spinal canal of 12.9 mm was found, indicating a certain degree of developmental stenosis. Patients with motor disturbances had a significantly smaller sagittal diameter of the bony spinal canal than did patients without motor disturbances. There was a linear correlation between the sagittal diameter of the bony cervical spinal canal and that of the hernia. The sagittal diameter, the area of the bony spinal canal, and diameter of the minimal bony intervertebral foramen were significantly smaller in patients with soft cervical disc herniation than in the control group. CONCLUSIONS: Results from this study strongly suggest that the degree and severity of neurologic symptoms accompanying cervical soft disc herniation are inversely related to the sagittal diameter and the area of the bony cervical spinal canal. The latter area is reduced in cases of developmental stenosis or because of soft disc herniation. Moreover, patients with soft cervical disc herniation have a significantly smaller sagittal diameter of the bony spinal canal, a significantly smaller minimal bony intervertebral foramen diameter, and a significantly smaller cross-sectional area of the bony cervical canal than do healthy matched individuals.

Total intravenous anesthesia and high-frequency jet ventilation during transthoracic endoscopic sympathectomy for treatment of essential hyperhidrosis palmaris: a new approach.

OBJECTIVE: To evaluate the effects of high-frequency jet ventilation (HFJV) applied to both lungs on hemodynamic parameters, oxygenation, and operating conditions during bilateral videothoracoscopic sympathectomy. DESIGN: A prospective, unblinded study. SETTING: An ambulatory surgical unit at a university medical center. PARTICIPANTS: 30 patients (11 men, 19 women), ASA status 1. INTERVENTION: Bilateral videothoracoscopic sympathectomies were performed using total intravenous anesthesia with propofol, alfentanil, and atracurium, and the patients were ventilated with an oxygen-air mixture using HFJV delivered to both lungs with a Hi-Lo Jet tracheal tube (Mallinckrodt). MEASUREMENTS AND MAIN RESULTS: Mean total anesthesia time was 55 +/- 13 minutes. Hemodynamic parameters remained stable during surgery, although ablation of the sympathetic ganglia induced three incidences of bradycardia (10% of the patients), which were responsive to atropine. Four patients developed oxygen desaturation (Sa O2 < 90%) after the creation of the pneumothorax. Surgical conditions were considered excellent by the surgeons. Concerning postoperative complications, a temporary Horner's syndrome was observed in one patient. Another patient had a mild residual pneumothorax on the first postoperative day that resolved without insertion of a chest tube. CONCLUSIONS: It was concluded that HFJV applied to both lungs is an easy and safe anesthetic technique that provides excellent surgical conditions and causes a minor incidence of morbidity.

Changes in cardiocirculatory autonomic function after thoracoscopic upper dorsal sympathicolysis for essential hyperhidrosis.

Essential hyperhidrosis (EH) is caused by an unexplained overactivity of the sympathetic fibers which pass through the upper dorsal sympathetic ganglia D2 and D3. Since the D2 and D3 ganglia are also involved in the sympathetic cardiac innervation, cardiocirculatory autonomic function may also be abnormal in EH. In order to study the function of the sympathetic nervous system in EH, and to assess the effects of thoracoscopic sympathiocolysis, cardiocirculatory autonomic function tests were performed in 13 consecutive patients with EH, before (baseline) and 6 weeks after the thoracoscopic intervention. Baseline data were also compared with data obtained from 13 matched healthy volunteers: EH patients showed an increased heart rate at rest, but only in the standing position (94 +/- 18.5 vs 78 +/- 10.9 bpm, P < 0.01), as well as an increased ratio of low to high frequency power of the heart rate variability in the standing position (5.92 +/- 4.4 vs 2.8 +/- 2.5, P < 0.05). Exercise tests were normal in every EH patient. After sympathiocolysis, heart rate at rest (sitting on the cycloergometer) had decreased (75.4 +/- 13 vs 90.4 +/- 16.5 bpm, P < 0.05), as well as heart rate at maximal exercise (165.2 +/- 14.8 vs 180 +/- 10 bpm, P < 0.05). Exercise capacity and the cardiorespiratory responses to exercise were, however, unchanged after sympathicolysis. Resting heart rate in the lying (66 +/- 10 vs 76 +/- 15 bpm, P < 0.05) and standing positions (82 +/- 13.8 vs 94 +/- 18.5 bpm, P < 0.05), and the diastolic blood pressure reaction to a handgrip test (73.6 +/- 8.6 vs 84.7 +/- 11.6 mmHg, P < 0.05) were also lowered after sympathicolysis. In conclusion, patients with EH show an overfunctioning of the sympathetic system which is characterised by an increased reaction to stress (standing, exercise), whereas resting sympathetic tone is unaffected. Thoracoscopic D2-D3 sympathicolysis corrects this hyperfunction and has a partial beta-blocker-like activity, which results in a decrease in heart rate at rest and during maximal exercise, and in the diastolic blood pressure response to the handgrip test. Further studies are needed to assess the long-term consequences of this procedure.

A simplified T2-T3 thoracoscopic sympathicolysis technique for the treatment of essential hyperhidrosis: short-term results in 100 patients.

A simplified one-time bilateral thoracoscopic T2-T3 sympathicolysis technique using single-lumen endotracheal intubation with high frequency jet ventilation and electrocautery destruction ("sympathicolysis") of the sympathetic ganglia was applied in 100 consecutive patients with severe essential hyperhidrosis (EH). Providing a pleural space can be created, this technique was proven simple and safe, and short-term clinical results were excellent: palmar hyperhidrosis was cured in 98% of patients, and axillar and plantar improvement was achieved in 62 and 65% of patients, respectively. Side-effects and complications were minor (compensatory hyperhidrosis) or self-limiting (pain). These data confirm the safety and efficacy of thoracoscopic sympathetic interventions for the treatment of EH, and support the evolution toward simplified methodologies.

Thoracoscopic sympathicolysis for essential hyperhidrosis: immediate and one year follow-up results in 35 patients and review of the literature.

Various treatments for essential hyperhidrosis are available. The aim of this study is to present our experience with a simplified thoracoscopic sympathicolysis technique in this disorder, and to confront our results with data in the literature, 35 consecutive patients (11 male, 24 female, age 12-44 years) with essential hyperhidrosis, refractory to "conventional" medical treatment presenting between August 1993 and May 1994 were studied. Bilateral D2-D3 sympathicolysis was performed using a simplified one-time bilateral thoracoscopic procedure under general anaesthesia. Clinical scores, complications and side effects were recorded one week, one month and one year after the intervention. Severe hyperhidrosis was present in the hands in 100%, axillae in 66% and soles of the feet in 86% of patients. In one patient, only a unilateral intervention was possible due to pleural adhesions. In the other 34 patients, palmar hyperhidrosis was completely and permanently relieved in 100% of cases. Axillar hyperhidrosis was significantly improved after one year in 91% of patients, 52% of which showed a complete disappearance of hyperhidrosis. Side effects and complications were minimal. There were no permanent pleural, neurological (Horner) or other sequellae. Patient satisfaction was invariably very high. These findings compare favourably with historical data in the literature.

Cardiopulmonary exercise testing following bilateral thoracoscopic sympathicolysis in patients with essential hyperhidrosis.

BACKGROUND: Essential hyperhidrosis is characterised by an overactivity of the sympathetic fibres passing through the upper dorsal sympathetic ganglia D2-D3. Anatomical interruption at the D2-D3 level is a highly effective treatment for essential hyperhidrosis but also causes (partial) cardiac denervation and, after surgical sympathicolysis, important impairment of cardiopulmonary exercise function has been observed. The purpose of this study was to compare the results of cardiopulmonary exercise testing between patients with essential hyperhidrosis and a normal control population, and to examine the effects of thoracoscopic D2-D3 sympathicolysis on cardiopulmonary exercise capacity in patients with essential hyperhidrosis. METHODS: maximal, symptom limited incremental exercise tests were performed in 26 patients with severe essential hyperhidrosis one week before and one month after D2-D3 thoracoscopic sympathicolysis, and in 14 age and sex matched healthy volunteers. D2-D3 thoracoscopic sympathicolysis was performed using a simplified one stage bilateral procedure. RESULTS: Palmar hyperhidrosis was relieved in every patient, confirming the D2-D3 denervation. A higher peak heart rate (7%) was seen in the patient group than in the normal subjects, but ll other cardiovascular, metabolic, and respiratory parameters were similar. After D2-D3 thoracoscopic sympathicolysis, heart rate at rest (13%) and at peak exercise (7%) were reduced, together with an increase in oxygen pulse. All other parameters remained unchanged. CONCLUSIONS: Sympathetic overactivity relevant to cardiovascular function in essential hyperhidrosis is evident only during sympathetic stimulation. D2-D3 thoracoscopic sympathicolysis causes a small and asymptomatic reduction in maximal and resting heart rate and is not associated with a decrease in exercise capacity, in contrast with the detrimental effects on exercise capacity of open surgical sympathectomy.

Spinal cord stimulation in animal models of mononeuropathy: effects on the withdrawal response and the flexor reflex.

Spinal cord stimulation (SCS) is efficacious for pain due to injury of peripheral nerves, and therefore models of mononeuropathy appear to be particularly suitable for an experimental approach to the study of mechanisms underlying the clinical effect of this mode of treatment in chronic neuropathic pain. Virtually all previous experimental studies on SCS have utilized acute and nociceptive types of peripheral pain stimuli to explore the attenuating effects of SCS. In the present study we made use of the two models of supposedly painful neuropathy developed by Bennett and Xie (1988) and Seltzer et al. (1990) to explore the effect of SCS applied with stimulus parameters similar to those used in clinical practice. In rats subjected to ligatures of the sciatic nerve according to these two methods, SCS was applied via chronically implanted electrodes, or acutely via a laminectomy in the lower thoracic region. In awake, freely moving animals SCS produced a marked increase of the withdrawal thresholds to innocuous mechanical stimuli in the form of von Frey filaments. This threshold elevation lasted for up to 40 min after 10 min of SCS. In about one-half of the animals there was also a moderate, but short-lasting increase in the intact leg. The degree and duration of the withdrawal threshold elevation was clearly related to the intensity of SCS which was kept below the level of which a response in the thoracic or leg musculature was produced. In a second series of experiments the effect of SCS, applied acutely via a laminectomy, on the early component (latency: 8-12 msec) of the flexor reflex was studied. As a result of nerve ligation with either of the methods used, the thresholds for evoking the early as well as the late component in the nerve-ligated leg were significantly lower than in the intact one. SCS resulted in a marked and long-lasting increase of the threshold of the early component in the nerve-ligated leg. On the intact side only a slight and short-lasting increase was observed. The late, C fibre-mediated component was not influenced by SCS. The first component of the flexor reflex is conceivably mediated by A beta-fibre activation and it presumably corresponds to the withdrawal response induced by innocuous mechanical stimuli. The lack of effect of SCS on the late reflex component indicates that it selectively influences transmission of A-fibre activity. (ABSTRACT TRUNCATED AT 400 WORDS)

Cortical stimulation for central neuropathic pain: 3-D surface MRI for easy determination of the motor cortex.

Motor cortex electric stimulation has been reported to be effective for the treatment of central post-stroke pain and trigeminal neuropathic pain. Five patients with pain due to injury of the trigeminal nerve and with abnormalities of facial sensibility, as well as two patients suffering of a post-stroke thalamic pain, were subjected to stimulation applied epidurally on the motor cortex. Quadripolar electrodes were implanted under local anaesthesia and the precise location of the motor cortex was determined on three-dimensional surface MRI the day prior to surgery. In our experience, correct topographic localization of the electrode on the motor cortex seems to be crucial to obtain pain reduction.

Sympathetic mediation of peripheral vasodilation induced by spinal cord stimulation: animal studies of the role of cholinergic and adrenergic receptor subtypes.

Electric spinal cord stimulation (SCS) is widely used as a treatment modality for ischemic pain in peripheral arterial insufficiency. The background for the therapeutic effect may be a temporary inhibition of sympathetically maintained peripheral vasoconstriction. In this series of experiments, the involvement of different types of cholinergic and adrenergic receptor subclasses in the vasodilatory effect was explored in anesthetized rats. The microcirculation in hindlimb skin and hamstring muscle was studied by the laser Doppler technique. The ganglionic blocker hexamethonium as well as the nicotinic receptor antagonist chlorisondamine abolished the effect in both vascular beds, whereas the muscarinic receptor antagonists pirenzepine and atropine were ineffective. Among the adrenergic receptor active compounds, phentolamine, prazosine (an alpha 1-receptor antagonist), and clonidine in high doses suppressed the SCS-induced vasodilation. Yohimbine (an alpha 2-receptor antagonist) did not alter the effect. The beta-adrenergic compounds had a differential effect on muscle and skin perfusion. Atenolol, a beta 1-receptor antagonist, inhibited SCS-induced vasodilation only in the skin, whereas the beta 2-receptor antagonist butoxamine selectively depressed the muscle response. The vasodilatory effect of SCS in the animal model used here seems to a large extent to be mediated by an inhibitory effect on peripheral vasoconstriction maintained via efferent sympathetic activity involving nicotinic transmission in the ganglia and the postganglionic alpha 1-adrenoreceptors. The involvement of beta-receptors seems to be different in skin and muscle, beta 1 being more important for the changes in the skin and beta 2 being more important for those in muscle. The high-intensity antidromic response, earlier believed to explain how SCS exerted its vasodilatory effect, was resistant to cholinergic and adrenergic manipulations and seems to depend on entirely different mechanisms.

Biotransformation of locally applied L-dopa in the corpus striatum of the hemi-parkinsonian rat studied with microdialysis.

Microdialysis was used to study the biotransformation of L-dopa in intact and denervated striata of rats with a unilateral 6-hydroxydopamine (6-OHDA) lesion of the substantia nigra. Microdialysis probes were placed in the intact and in the denervated striatum. Observations were then made on freely moving rats. Extracellular levels of dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC) and 4-hydroxy-3-methoxyphenylacetic acid (homovanillic acid; HVA) were monitored before, during and after the local administration of L-dopa via the microdialysis probe for 20 min. A dose-dependent increase in extracellular dopamine levels was seen in intact striatum after application of L-dopa in concentrations ranging between 100 nmol/l and 10 mumol/l. In the denervated striatum, the severity of the lesion influenced dopamine formation, so that no dose-effect relation could be established. The effects of the continuous intra striatal infusion of nomifensine, tetrodotoxin or benserazide on the L-dopa-induced dopamine outflow revealed that in the intact striatum this dopamine release is mainly voltage dependent. It was concluded that in the denervated striatum other cells of non-neuronal origin and containing aromatic L-amino acid decarboxylase make a major contribution to the increase in extracellular dopamine levels. Furthermore, L-dopa itself shows no dopamine-releasing properties, at least under the present experimental conditions.

Photochemically induced spinal cord ischaemia in rats: assessment of blood flow by laser Doppler flowmetry.

A photochemical technique was used to create central nervous system ischaemia in rats. Changes in blood flow in the spinal cord were assessed by laser Doppler flowmetry. The Th11 spinal cord segment was irradiated by an argon ion laser after intravenous injection of an organic dye, erythrosin B, to rats with or without a laminectomy. In the group of laminectomized rats, laser irradiation for 5 s did not influence cord blood flow, but 10 s irradiation caused a 25% decrease of blood flow, which normalized within 20 min. Decreases of 50 and 80% in spinal cord blood flow were noted after 20 s and after 1 min of laser irradiation, respectively, with no recovery observed after 20 min. In the group of rats without a laminectomy, 1 min of laser irradiation caused approximately a 25% decrease of spinal cord blood flow, which gradually recovered within 12 min, whereas 5 min of laser irradiation caused a more severe reduction of spinal cord blood flow (45%) with some recovery was observed 30 min later. We could thus confirm that the interaction between a photosensitizing dye and laser irradiation reduced the regional spinal cord blood flow and the extent of this effect could be modified by varying the duration of laser irradiation. The present results therefore provide further support for using this photochemical technique to create animal models of central nervous system ischaemia.

Easy preoperative planning of deeply located brain lesions using external skin reference and 3-dimensional surface MRI.

Open skull surgery of deeply located intracerebral lesions requires precise determination of the treatment area in 3-dimensional (3-D) space. 3-D MRI can give important additional information in presurgical determination of the surgical approach to the target, taking into account highly functional brain areas and important vascular structures. The day before surgery, a grid composed of 9 tubings intersecting at 90 degrees at 1 cm intervals and filled with a CuSO4 solution is firmly attached to the skin of the patient's head in the presumed region of the craniotomy. A 3-D turbo-FLASH sequence is then performed in the sagittal plane after intravenous Gd-DOTA injection on a 1T Magneton. 3-D surface reconstruction of the cortical gyri and sulci is performed. Once the gyri are identified, the 3-D program is then implemented in order to perform a color display of the cortical veins and of the tumor boundaries. The surgical access is then chosen by the surgeon, taking into account highly functional areas. Finally, the boundaries of the tumor are projected on the cortex reconstruction and on the external reference placed on the skin. The entry place for surgery as well as the size of craniotomy are drawn on the skin and the tubed grid is removed. The accuracy of this method tested in 9 patients with deeply located brain tumors or arteriovenous malformations was very satisfactory.(ABSTRACT TRUNCATED AT 250 WORDS)

An experimental animal model of spinal cord stimulation for pain.

In spite of the routine usage of spinal cord stimulation (SCS) as treatment of chronic pain, there is an insufficient understanding of the mechanisms underlying its effect. The method was originally developed as a spin-off from experiments demonstrating the inhibitory control of nociceptive signals by the activation of large afferent fibers, and on the basis of these findings the gate-control theory was advanced. Later experiments showed that stimulation of the dorsal columns can inhibit the relay of nociceptive impulses to second-order neurons in the dorsal horn. It should be emphasized that all these experiments were performed with acute noxious stimuli; it is now universally recognized that SCS in patients is preferentially, or exclusively, effective for chronic neuropathic types of pain. For these and other reasons the mode of action of SCS in clinical pain cannot be inferred from these early animal experiments. In ongoing studies we have used animal models of mononeuropathy (rat) in which we have applied SCS acutely or chronically with stimulation parameters similar to those used in patients. In these animals the first component of the flexor reflex appears with a lower stimulus threshold in the nerve lesioned than in the intact, sham-operated leg. SCS was applied at the approximate level of Th-XII during 10-20 min and produced a marked augmentation of the stimulus threshold. This abnormally high threshold was not normalized until 30-60 min after the end of SCS. In awake animals SCS was applied via an implanted spinal electrode and the effect on behavior changes associated with mononeuropathy was studied.(ABSTRACT TRUNCATED AT 250 WORDS)

Motor cortex stimulation as treatment of trigeminal neuropathic pain.

A report is given on first experiences with motor cortex stimulation in 10 patients with different forms of neuropathic pain. Three of them had central pain as sequelae of cerebrovascular disease. In none of them did the stimulation provide pain relief. Two patients had pain from peripheral nerve injuries. One did not respond, but the other obtained about 50% pain relief. The remaining 5 patients with trigeminal neuropathy experienced definite pain relief varying between 60 and 90%. During test stimulation most patients had one or two short-lasting generalized seizures. But no one had any motor effects after permanent implantation. Motor cortex stimulation appears to be a new and promising possibility of pain treatment, especially in cases with trigeminal neuropathy, but many problems have yet to be solved, before a clear indication could be given.

Expression of interleukin (IL)-1 beta, IL-6 and their respective receptors in the normal rat brain and after injury.

The expression of interleukin (IL)-1 beta, IL-6 and their respective receptors has been studied in the rat brain before and up to 24 h after injury. Messenger RNA transcripts of these four genes were detected by in situ hybridization (ISH) in different structures of the intact brain. The distribution was very similar for IL-1 beta, IL-6 and IL-6 receptor (IL-6R). The expression of IL-1R was more widespread. Within hours after injury, an increased expression of IL-1 beta, and thereafter of IL-6 was documented. The expression of IL-1R and IL-6R was also increased. This expression was bilateral and not restricted to the injured area. Within 24 h, all ISH patterns had returned to normal. The molecular data were confirmed by protein data. Indeed, the distribution of IL-6 (detected by immunocytochemistry) agreed with the ISH patterns for IL-6. Furthermore, extracellular fluid was collected by microdialysis at the site of the lesion during 12 h and successive fractions were assayed for the presence of bioactive IL-1 and IL-6. Increases in IL-1 and later in IL-6 levels were detected. The rapid and concomitant increased expression of IL-1 beta, IL-6 and their receptors after injury stresses their possible early role in inflammatory mechanisms also in the brain, before any recruitment of inflammatory cells from remote nervous and not nervous areas.

Biotransformation of L-dopa in striatum and substantia nigra of rats with a unilateral, nigrostriatal lesion: a microdialysis study.

Microdialysis was used to study the biotransformation of L-DOPA in the striatum and substantia nigra of rats with a unilateral 6-hydroxydopamine (6-OHDA) lesion of the substantia nigra. The animals were pretreated with carbidopa (50 mg/kg p.o.) for 5 days. They were anaesthetized, and microdialysis probes were implanted into the intact and denervated striatum and into the intact and lesioned substantia nigra. The biotransformation of L-DOPA (5 mg/kg i.p.) in these regions was investigated. These results were compared with those obtained after administration of a much higher dose of L-DOPA (100 mg/kg i.p.). Changes in extracellular L-DOPA, 3-O-methyldopa (3-OMD), dopamine, dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) were determined by HPLC with electrochemical detection. Although rats with a unilateral nigrostriatal lesion did not show rotational behaviour after 5 mg/kg L-DOPA, DA levels were increased significantly both in the intact and the denervated striatum and in the intact and the lesioned substantia nigra. This increase was most pronounced in the denervated striatum. At 100 mg/kg L-DOPA, the increases in extracellular dopamine in intact and denervated striatum were about twice as high as the increases observed at the lower dose. A similar increase was observed in the intact substantia nigra. However, in the lesioned substantia nigra there was a fourfold increase. L-DOPA, at both doses, was evenly distributed between the brain areas studied and the lesion had no effect on the uptake of the drug at the blood-brain barrier.(ABSTRACT TRUNCATED AT 250 WORDS)

Spinal arachnoiditis mimicking a spinal cord tumor: a case report and review of the literature.

We report on an unusual case of idiopathic arachnoiditis mimicking a spinal cord tumor in a 50-year-old man with progressive paraparesis. The medical imaging work-up showed an enlarged terminal cone with adjacent cysts. Although there was no enhancement of the terminal cone or the surrounding structures, the diagnosis of spinal cord tumor was maintained and surgery was carried out. Exploration of the cauda equina and the tissue surrounding the terminal cone did not reveal a tumor. The patient improved dramatically after surgery but the symptoms recurred 1 year later. We review arachnoiditis, its pathology, and its treatment with special attention drawn to the primary form of spinal arachnoiditis.