[Monitoring of somatosensory evoked potentials during surgery for scoliosis in young adults: apropos of 33 cases]. / Surveillance per-opératoire des scolioses chez l'adulte jeune par les potentiels évoqués somesthésiques: à propos de 33 cas.

The risk of serious neurologic complications in spinal surgery for scoliosis is not insignificant. The recording of cortical somatosensory evoked potentials (CSEP) is an electrophysiological method of monitoring during surgery. Measurement of CSEPs was carried out before, during and after surgery in a preliminary series of 33 patients. These recordings were made: after induction of anesthesia and exposure of the spine; after instrumentation but without correction; after maximum traction; and at termination of surgery. The aim of this work was to establish alarm criteria. Statistical analysis showed a significant increase in latencies after instrumentation without correction, and after maximum traction. The alarm criteria were determined as an increase of more than 5 msec in the first positive deflection associated with an unusual drop in amplitude (over 75%). If these anomalies persist, the "wake-up test" must be used. In practice, this monitoring has often aided in reducing the period of surgery by using the "wake-up test" in a few selected cases.

[Trigeminal somatosensory evoked potentials (V2 and V3) in the healthy Senegalese adult]. / Potentiels évoqués somesthésiques du trijumeau (V2 et V3) chez l'adulte sénégalais sain.

Somatosensory trigeminal (V2 and V3) potentials were evoked in 20, healthy, Senegalese subjects (10 men and 10 women). Norms hereby established differ little from those in literature, doubtless because skull patterns do not sufficiently influence the latency or morphology of these potentials, and because the racial factor plays no role here, not even with respect to size as in quoted somatosensory potentials for the extremities.

Propofol anaesthesia alters somatosensory evoked cortical potentials.

This study evaluated the effects of propofol on somatosensory evoked cortical potentials in 20 ASA grade 1 or 2 patients who underwent spinal surgery. Anaesthesia consisted of propofol, dextromoramide, 50% nitrous oxide and oxygen mixture. The induction dose of propofol was 2 mg/kg and was followed by an infusion of 6 mg/kg for the first hour and 3 mg/kg subsequently. Somatosensory evoked cortical potentials were recorded on the scalp and compared to pre-operative values using Student's paired t-test. We observed a significant depression of evoked potential 10 minutes after induction, which continued until the early phase of recovery. Because of its short and quickly reversible action, propofol is an acceptable agent when clinical monitoring of the spinal cord is indicated but is not satisfactory when monitoring has to be based on somatosensory cortical evoked potentials.

[Propofol versus methohexital in the surgery of the spinal canal]. / Propofol versus méthohexital dans la chirurgie du canal rachidien.

The aim of this study was to compare the quality of postanaesthetic recovery after anaesthesia with methohexitone (M) or with propofol (P). Thirty patients undergoing spinal surgery were randomly assigned to either group. The induction dose was 2 mg . kg-1 for both M and P. Anaesthesia was maintained by continuous infusion. The rate was 0.15 mg . kg-1 . min-1 for P and 0.07 mg . kg-1 . min-1 for M. Analgesia was obtained with fentanyl with the same doses in both groups. The maintenance doses were subsequently decreased by 50 and 75% of the initial values. This work compared the quality induction and the criteria of recovery (Aldrete score, Newman test). In two patients in each group, sensory evoked potentials (SEP) were recorded to monitor neurological integrity. The quality of induction was similar in both groups. Awakening was significantly more rapid in group P. The SEP were much decreased in group P, whilst there were few changes in group M. Monitoring of medullar integrity is mandatory in spinal surgery, requiring a rapid recovery. This objective was obtained with shorter delays in patients anaesthetized with propofol than in those who had received methohexitone. However, the former, at the doses used, seemed to depress the SEP.

[Effort-induced malignant hyperthermia. Electromyographic anomalies with a myogenic component. 10 cases]. / L'hyperthermie maligne d'effort. Anomalies électromyographiques d'aspect myogène. Dix observations.

Exertion malignant hyperthermia, usually regarded as a form of heat stroke, is mainly observed in young apparently healthy men enlisted in the army and subjected to intensive physical exertion in a warm and damp environment. It is frequently lethal. Ten cases with favourable outcome are reported. In 8 patients, EMG tracings recorded several months after the acute episode showed myogenic abnormalities. Computer-aided analysis of motor units showed a 42% reduction in mean duration of the motor unit collected from the brachial biceps and a 44% reduction of signal energy as compared with controls. Two possible reasons for these abnormalities are discussed: they may result from rhabdomyolysis or from a pre-existing muscular pathology.

[An application of balloon probes. Preoperative electrophysiological test of the tolerance to temporal occlusion of the artery of cervical enlargement]. / Une application des sondes à ballonnets. Test pré-opératoire par méthode électrophysiologique de la tolérance à l'occlusion temporale de l'artére du renflement cervical.

The authors report a case of testing of the temporary occlusion of origin of the radiculo-medullar artery for the cervical enlargement by balloon occlusion and both testing by clinical evaluation and evaluation of somesthesic evoked potentials and F wave. This testing allowed the surgical removal of a malignant tumor of the cervical vertebra including the vertebral artery and the origin of the radiculo-medullar artery for the cervical enlargement. About this case, they discuss possibilities and the theorical value of these pre-operative tests.

[Deep alpha frequency coma after hanging not followed by immediate death. A report of two cases (author's transl)]. / Coma profond à fréquence alpha après pendaison non suivie de mort immédiate. A propos de deux observations.

Two cases of deep alpha frequency coma after unsuccessful hanging attempts are reported. Studies were conducted after similar cases in which vascular or traumatic brain stem lesions were at the origin of the coma, and in those secondary to cardiorespiratory arrest. A review of the EEG findings in cases reported in the published literature showed that these were more similar to cases with cardiorespiratory arrest than to those following brain stem lesions, in spite of the existence of angiographic anomalies observed in the vertebral arteries. The differential diagnosis and the prognostic value of the electroclinical picture are discussed, as well as the physiopathogenicity, which remains obscure.

[Von Eulenburg's congenital paramyotonia and aptitude for military service. Cases taken from a family with 25 cases since 1789]. / Paramyotonie congénitale de Von Eulenburg et aptitude au service armé. Observations tirées d'une famille groupant 25 cas, depuis 1789

The authors present four cases of von Eulenberg's paramyotonia. From the family history it was possible to follow the condition through seven generations since 1780; it confirms the autosomal dominant nature of genetic transmission, with almost complete penetrance. From the clinical standpoint, the condition observed is particularly pure, occurring exclusively in the cold. At no time were paralyses or adynamia independent of the myotonic phenomena and of temperature variations observed. The laboratory investigations carried out, ionic and enzyme, showed no abnormalities. Electromyographic study showed the presence of numerous true myotonic out-bursts, variable in shape and in amplitude, independant of the myotonic phenomenon, and present in the absence of exposure to cold. The effects of the condition on aptitude for military service are examined and in this respects the author recalls that the history of myotonia is intimately bound up with medico-military problems.