Posterior fossa surgery in the sitting position in a pregnant patient with cerebellopontine angle meningioma.

Primary brain tumours and pregnancy rarely occur together; meningioma and pregnancy is rarer still. We describe a 30-yr-old woman in the 25th week of pregnancy who underwent surgery in the sitting position for a large cerebellopontine angle meningioma that was compressing and displacing the pons and medulla. The surgical procedure and postoperative period were uneventful. This case demonstrates that when absolutely necessary, anaesthesia and neurosurgery for posterior fossa lesions can be successful during the second trimester of pregnancy. Furthermore, if indicated and if the operating team is experienced, the operation can be performed safely with the patient in the classical sitting position. It is emphasized that continuous and attentive monitoring of the mother and fetus are essential.

Sensitivity to vecuronium after botulinum toxin administration.

When used to treat focal dystonias, botulinum toxin may cause a transient impairment of neuromuscular transmission in muscles distant from those injected. These systemic effects are not clinically evident, but should not be ignored when patients are exposed to other drugs or conditions that also impair neuromuscular transmission. A patient is described who underwent general anesthesia twice during treatment with botulinum toxin for a long history of blepharospasm. On both occasions, the neuromuscular block produced by vecuronium (0.05 mg kg-1) was monitored in the abductor digiti minimi muscle. Compared with that observed in 24 individuals who were free from neuromuscular problems, the patient's sensitivity to vecuronium was low 90 days after the seventh treatment with toxin and normal 8 days after the ninth. The possibility is considered that repeated treatments with the toxin may cause continuous remodeling of neuromuscular junctions and may cause the patient to develop some tolerance to the action of neuromuscular blockers.

Neurologic symptoms after epidural anaesthesia. Report of three cases.

We describe 3 patients, who exhibited neurological symptoms after single dose epidural anaesthesia. In patient 1 an unrecognized spinal arteriovenous fistula (AVF) caused paraparesis following epidural block. The dilated veins draining an AVF are space-occupying structures and the injection of the anaesthetic solution may have precipitated latent ischaemic hypoxia of the spinal cord due to raised venous pressure. In patient 2, epidural block was followed by postoperative permanent saddle pain and hypoaesthesia. The injection of the anaesthetic in a narrow spinal canal with multiple discal protrusions and restriction of interlaminar foramina may have acutely produced mechanical compression of the spinal cord or roots. Patient 3 exhibited post-epidural block spinal arachnoiditis. Although the few reported cases of this syndrome exhibit severe neurological damage, our patient presented with scarse symptoms. Our cases point out the importance of accurate neurological history and examination of candidates for epidural anaesthesia and of accurate anaesthetic history for neurological patients.

Neurological examination in patients recovering from general anesthesia.

We performed serial neurological evaluations on 86 patients who underwent surgery for herniated lumbar disk during the first 3 hours after the end of anesthesia (isoflurane-N20-02 for 25 patients, halothane-N20-02 for 38, fentanyl-droperidol-N20-02 for 23). At time 0, the idiomuscular response to percussion of the extensor carpi muscle was present in every patient, while tendon reflexes were always absent. Hyperreflexia was as frequent as shivering, but it took place earlier; we could determine no correlation between these two phenomena. There was no correlation between shivering and rectal temperature of the patients. Although almost all the patients were cooperative and could correctly calculate 100-7, the post-hyperventilation-apnea test was positive in 35 patients at time 120 minutes: this suggests that many patients considered "awake" still exhibit neurological abnormalities, such as inadequate respiratory drive.

[General anesthesia for magnetic resonance. Experience on 100 cases]. / Anestesia generale per la risonanza magnetica. Esperienza su 100 casi.

The diffusion of magnetic resonance imaging as a powerful non-invasive diagnostic procedure has led to an increasing request for general anaesthesia in patients who cannot lie still and/or who cannot guarantee adequate spontaneous breathing during the procedure. We report our own experience in 100 patients of this kind, in whom the need for general anaesthesia was due to neurological problems and/or tender age. Anaesthesia and monitoring devices were either devoted of ferromagnetic properties (allowing their location near the patient; as the ARM-S88 portable ventilator, which we used for adult patients) or connected to the patient with long connectors (allowing their location outside the resonance magnetic field; as the Draeger-Babylog pressometric ventilator, which we used in pediatric patients). On these bases administration of intravenous (86 patients) and inhalation (14 patients) anaesthesia during magnetic resonance proved safe in our experience.

[Labetalol in the prophylaxis of postoperative arterial hypertension in surgery of the posterior cranial fossa]. / Il labetalolo come profilassi della ipertensione arteriosa post-operatoria nella chirurgia della fossa cranica posteriore.

Increased catecholamines are one of the factors responsible for post-operative arterial hypertension. In order to prevent this severe complication labetalol, an alpha and beta blocking drug, was infused following the closure of the dura mater in half of the patients studied. For two hours after surgery blood pressure values in treated patients were constantly lower than those recorded in the control group, thus confirming the efficacy of this drug in preventing the cardiocirculatory effects of increased adrenalin and noradrenalin.

Submaximal nerve stimulation with the Datex relaxograph NMT monitor in myasthenia gravis.

Recently submaximal train-of-four stimulation of motor nerves has been reported as a reliable technique for monitoring the neuromuscular function in patients awakening from anaesthesia, in order to prevent residual curarization. On the basis of the similarity between curarization and Myasthenia Gravis, we studied the neuromuscular impairment of four myasthenic patients by means of a commercially available monitor, which has been designed for routine application in the operating room. We demonstrate that the cardinal features of Myasthenia Gravis can be easily detected with this simple and painless method.

Sensitivity to curare in patients with upper and lower motor neurone dysfunction.

Sensitivity to the action of nondepolarising relaxants was compared in muscles of upper and lower limbs in four syringomyelic patients undergoing elective neurosurgical procedures. It was observed that muscles with signs of lower motor neurone dysfunction are supersensitive to the action of nondepolarising relaxants. Terminal sprouting of motor axons and the occurrence of newly formed neuromuscular junctions may be responsible for a low synaptic efficacy and may explain the high sensitivity to factors that reduce the safety margin of neuromuscular transmission.

Monitoring of curarisation in patients with tetraparesis.

Neuromuscular blockade induced by pancuronium was monitored on the trapezius and abductor digiti minimi muscles in three patients with upper motor neurone lesions: one patient was hemiparetic and two were tetraparetic. A greater sensitivity to pancuronium was always observed on the trapezius muscle. It is suggested that the assessment of curarisation is more reliable on proximal than on distal muscles if the patient's sensitivity to relaxants is expected to be generally low.

[Pre- and postoperative evaluation of plasma creatine kinase in 142 children subjected to "uncomplicated" anesthesia in muscle biopsy]. / Valutazione pre e postoperatoria della creatinkinasi plasmatica in 142 bambini sottoposti "senza complicazioni" ad anestesia per biopsia muscolare.

Pre- and postoperative serum CK activity is evaluated in 142 children submitted, "uneventfully", to diagnostic muscle biopsy under halothane (77 patients), ketamine (50 patients) or "local" (15 patients) anaesthesia. The purpose was to ascertain whether or not anaesthesia-induced-rhabdomyolysis (AR) was an asymptomatic (and unrecognized) complication of "uneventful" anaesthesia. The majority of patients with low preoperative CK values showed a slight increase of serum CK activity on the first postoperative day. On the contrary, a postoperative decrease was observed in the majority of patients with high preoperative values (namely in almost all ketamine patients and in 2/3 of halothane-patients). In no case postoperative increase reached a value suggesting the occurrence of AR even though a postoperative value of 16480 U/I was observed in a patient with Duchenne muscular dystrophy after halothane anaesthesia. Sudden interruption of motor activity induced by general anaesthesia seems to be the most important factor in reducing the release of CK from muscle. When preoperative release is low, any further postoperative reduction is not sufficient to balance the moderate increase of CK produced by the surgical procedure; the opposite should happen in patients presenting with high preoperative release. So far as anaesthetics are concerned, our data seem to suggest that ketamine has a higher "protective" role compared to halothane.

Increased activation effects of succinylcholine in neurological patients.

Succinylcholine, a depolarizing muscle relaxant with both activating and desensitizing effects, is used to facilitate endotracheal intubation. The activating effects were found to be above-normal on induction of anesthesia in 7 neurological patients: generalized muscle spasm in 1 myotonic patient, contractures or prolonged contractions in "anatomically" denervated muscles (1 patient), in "functionally" denervated muscles (1 patient) and in "centrally" denervated muscles (4 patients). One of these four presented hyperkalemia and cardiocirculatory collapse. It is important to differentiate these anomalous responses to succinylcholine from those occurring as early signs of rhabdomyolysis or malignant hyperthermia.