Multicolumn spinal cord stimulation for significant low back pain in failed back surgery syndrome: design of a national, multicentre, randomized, controlled health economics trial (ESTIMET Study).

BACKGROUND: Many studies have demonstrated the efficacy of spinal cord stimulation (SCS) for chronic neuropathic radicular pain over recent decades, but despite global favourable outcomes in failed back surgery syndrome (FBSS) with leg pain, the back pain component remains poorly controlled by neurostimulation. Technological and scientific progress has led to the development of new SCS leads, comprising a multicolumn design and a greater number of contacts. The efficacy of multicolumn SCS lead configurations for the treatment of the back pain component of FBSS has recently been suggested by pilot studies. However, a randomized controlled trial must be conducted to confirm the efficacy of new generation multicolumn SCS. Évaluation médico-économique de la STImulation MEdullaire mulTi-colonnes (ESTIMET) is a multicentre, randomized study designed to compare the clinical efficacy and health economics aspects of mono- vs. multicolumn SCS lead programming in FBSS patients with radicular pain and significant back pain. MATERIALS AND METHODS: FBSS patients with a radicular pain VAS score≥50mm, associated with a significant back pain component were recruited in 14 centres in France and implanted with multicolumn SCS. Before the lead implantation procedure, they were 1:1 randomized to monocolumn SCS (group 1) or multicolumn SCS (group 2). Programming was performed using only one column for group 1 and full use of the 3 columns for group 2. Outcome assessment was performed at baseline (pre-implantation), and 1, 3, 6 and 12months post-implantation. The primary outcome measure was a reduction of the severity of low back pain (bVAS reduction≥50%) at the 6-month visit. Additional outcome measures were changes in global pain, leg pain, paraesthesia coverage mapping, functional capacities, quality of life, neuropsychological aspects, patient satisfaction and healthcare resource consumption. TRIAL STATUS: Trial recruitment started in May 2012. As of September 2013, all 14 study centres have been initiated and 112/115 patients have been enrolled. Preliminary results are expected to be published in 2015. TRIAL REGISTRATION: Clinical trial registration information-URL: www.clinicaltrials.gov. Unique identifier NCT01628237.

Microdialysis study of amino acid neurotransmitters in the spinal dorsal horn of patients undergoing microsurgical dorsal root entry zone lesioning. Technical note.

The aim of this study was to develop, for the first time in the human spinal dorsal horn (DH), an in vivo method for the study of amino acids (AAs). A microdialysis technique was used to sample AAs in the extracellular fluid of the DH apex in eight patients in whom surgery in the dorsal root entry zone (DREZ) was performed. Before making microsurgical lesions, specific concentric-type microdialysis probes were implanted over a 60-minute period in the DREZ and directed to the DH apex (10 implantations). The AA concentrations in the dialysates were determined using high-performance liquid chromatography with fluorescence detection. The concentrations of excitatory AAs (glutamate and aspartate) and inhibitory AAs (gamma-aminobutyric acid and glycine) decreased and were stabilized by 45 minutes after probe implantation, whereas the levels of nonneurotransmitter AAs (alanine and threonine) were not stabilized at 60 minutes. The ability of the probe to track the changes of extracellular AAs was demonstrated. Neither intra- nor postoperative microdialysis-related complications were observed (with a follow up of 18 months). The present study demonstrates that microdialysis can be performed safely in the human DH during DREZ lesioning. Despite technical and analytical limitations related to the intraoperative conditions, this technique offers new possibilities for clinical research on neurotransmitters involved in some relevant pathological states, especially in chronic pain and spasticity.

[Cerebrovascular reactivity to CO2 during general anesthesia maintained with either isoflurane-N2O or propofol-N2O. A comparative study by transcranial Doppler velocimetry]. / Réactivité vasculaire cérébrale au CO2 sous anesthésie générale entretenue par isoflurane-N2O ou propofol-N2O. Etude comparative par vélocimétrie Doppler transcrânienne.

OBJECTIVES: To compare, using transcranial doppler velocimetry (TDV), the cerebral blood flow velocity and CO2 reactivity during general anaesthesia maintained with either isoflurane-N2O-O2(IF) or propofol-N2O-O2 (PF) in adults with a normal brain. STUDY DESIGN: Nonrandomized controlled trial. PATIENTS: Forty ASA I patients (mean age 41 +/- 13 yrs, 15 F/35 M) undergoing surgery of the lumbar spine in prone position. The first 20 were allocated into the IF group and the subsequent 20 into the PF group. METHODS: General anaesthesia was induced with midazolam (0.05 mg.kg-1), phenoperidine (0.03 mg.kg-1), thiopentone (5 mg.kg-1), vecuronium (0.1 mg.kg-1) and maintained with N2O (50 vol %) and O2 (50 vol %) and either isoflurane (0.8 < Fet < 1 vol %) in IF group or propofol (6 mg.kg-1.h-1) in PF group. The vascular reactivity was assessed with velocimetry measurements (Angiodine DMS, with a probe transmitting a 2-MHz pulsed wave) of flow in the middle cerebral artery at a given PetCO2 (obtained by adjustments of VT) during systole (SV) and diastole (DV). Three measurements were made: at T1 (PetCO2 = 30 +/- 2 mmHg), at T2 (PetCO2 = 40 +/- 2) and at T3 (PetCO2 = 30 +/- 2 mmHg). RESULTS: In the IF group, VS increased by +32% at T2 (P = 0.006) with an increase of + 3.4 %/1 mmHg of PetCO2. Similarly, in the PF group VS increased by + 31 % at T2 (P < 0.0001) with an increase of 2.9 %/1 mmHg of PetCO2. In both groups the VS returned to baseline values at T3. In the IF group, VD increased by + 66% at T2 (P < 0.0001), with an increase of + 7%/1 mmHg of PetCO2. Similarly in the PF group, VD increased by + 61% (P < 0.0001) with an increase of + 5.7%/1 mmHg of PetCO2. In both groups the VD returned to baseline values at T3. CONCLUSIONS: During anaesthesia maintained with either isoflurane-N2O-O2 or propofol-N2O-O2, a change in PetCO2 results in similar changes in VS and VD. These anaesthetic agents preserve the cerebrovascular reactivity of the normal brain. The results of this study are in accordance with those obtained with other reference techniques in healthy volunteers. Transcranial doppler velocimetry can be a useful noninvasive tool of clinical research in neuroanaesthesia.

[Monitoring of intracranial pressure with intraparenchymal fiberoptic transducer. Technical aspects and clinical reliability]. / Monitorage de la pression intracrânienne par capteur intraparenchymateux à fibres optiques: aspects techniques et fiabilité clinique.

A fiberoptic intracranial pressure transducer (Camino) was assessed prospectively in 100 patients. In all, 122 sensors were inserted intraparenchymally at the bedside, without the help of a neurosurgeon. Before the procedure, patients were given 2 to 4 mg of phenoperidine. The scalp was opened over a few millimeters in the frontal paramedian area. A burr holc was made with a 2 mm bit. The dura mater was opened and a hollow screw inserted in the diploë. When the zero of the transducer had been obtained, a 5 cm length was inserted within the screw. The transducer was then about 5 mm deep within cerebral parenchyma. The procedure took an average of about 15 min. An intracerebral haematoma around the transducer occurred five times. One had to be drained surgically. There were no infectious complications. The daily baseline drift was about 0.3 mmHg. The system seemed to be reliable: there was close agreement between the intracranial pressure (ICP), neurological status and CT scan findings. In trauma cases, there was also good correlation between mean ICP and the basal cistern obliteration score, finally, ICP became equivalent to mean arterial blood pressure in all brain dead patients. It is concluded that this system may be used in all cases where ICP requires to be monitored, even when the lateral ventricles are no longer visible, or when craniotomy has been performed. This will most probably result in a more extended use of ICP monitoring in neurosurgical intensive care.

[Unilateral hydrocephalus caused by abscess of the choroid plexus]. / Hydrocéphalie unilatérale par abcès des plexus choroïdes.

A case of unilateral hydrocephalus due to an abscess in the ipsilateral choroid plexuses, and revealed by intracranial hypertension is reported. Treatment with ceftriaxone, metronidazol and thiophenicol was clinically and radiographically successful, without surgery 3 weeks later. Management and mechanisms are discussed.

[A rare and severe complication of meningeal hemorrhage: spinal arachnoiditis with paraplegia]. / Complication rare et grave de l'hémorragie méningée: arachnoidite dorsale avec paraplégie.

This observation relates a case of spinal arachnoiditis with paraplegia, for a 56 year old patient hospitalized for a S.A.H. by a ruptured aneurysm of the P.I.C.A. This patient present some complications, requiring a prolonged ventilatory support with a tracheostomy, a ventricular shunt for hydrocephalus. The treatment is only surgical, and the corticosteroids delay the evolution, but without successful outcome.