J. Maarrawi

Lyon Neuroscience Research Center, Lyons, Rhône-Alpes, France

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Publications (42)65.97 Total impact

  • J. Maarrawi, L. Garcia-Larrea
    Douleur et Analgésie 03/2014; 27(1):19-31. DOI:10.1007/s11724-014-0373-4 · 0.09 Impact Factor
  • Neurochirurgie 12/2013; 59(6):259. DOI:10.1016/j.neuchi.2013.10.109 · 0.47 Impact Factor
  • Neurochirurgie 12/2013; 59(6):231–232. DOI:10.1016/j.neuchi.2013.10.025 · 0.47 Impact Factor
  • Neurochirurgie 12/2013; 59(6):248. DOI:10.1016/j.neuchi.2013.10.075 · 0.47 Impact Factor
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    ABSTRACT: Background / Purpose: Synergy between clonidine and bupivacaine, well-established for nerve block, is less documented for post-operative wound pain following pre-incision wound infiltration, especially in spine surgery.ClinicalTrials.gov identifier: NCT01902108 Main conclusion: Addition of clonidine to bupivacaine in wound infiltration for posterior spine surgery leads to a better late post-operative pain control. This effect is probably mediated by a delayed local anti-inflammatory effect of the clonidine itself, as was proved in animal studies.
    8th EFIC Congress “Pain in Europe” 2013; 11/2013
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    ABSTRACT: Background / Purpose: Chronic neck pain (CNP) is a common complex clinical entity which is most often mistreated. We conducted a prospective randomized double-blind controlled study to test efficacy and tolerance of 5mg amitriptyline in the management of CNP. Main conclusion: Low dose (5mg) amitriptyline proved to be an effective and safe mean of pain relief for chronic neck pain versus placebo.
    8th EFIC Congress “Pain in Europe” 2013; 11/2013
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    ABSTRACT: The clinical effect of motor cortex stimulation (MCS) for neuropathic pain (NP) is thought to be largely mediated by the secretion of endogenous opioids, both in humans and animal models. Since opioid receptor density is itself decreased in NP patients, we investigated whether the magnitude and distribution of remaining opioid receptors in NP patients could represent a biological predictor of pain-relieving MCS effects. Using (11)C-Diprenorphine PET-scan, opioid receptor availability was assessed in 15 patients suffering refractory neuropathic pain, who subsequently received chronically implanted MCS. Each patient underwent 2 preoperative baseline scans at 2 weeks interval and was clinically assessed after 7 months of chronic MCS. The level of preoperative opioid-binding in insula, thalamus, periaqueductal grey, anterior cingulate, orbito-frontal cortex, was significantly and positively correlated with postoperative pain relief at 7 months. Patients with receptor density values below the lower limits in age-matched controls in thalamus, PAG and contralateral insula were the least likely to benefit from MCS. Opioid-receptor availability in pre-operative PET-scans appears related to MCS efficacy in neuropathic pain, and may help clinicians select the candidates most likely to benefit from this procedure.
    Pain 07/2013; 154(11). DOI:10.1016/j.pain.2013.07.042 · 5.84 Impact Factor
  • Neurochirurgie 12/2012; 58(6):426. DOI:10.1016/j.neuchi.2012.10.057 · 0.47 Impact Factor
  • Neurochirurgie 12/2012; 58(6):409. DOI:10.1016/j.neuchi.2012.10.003 · 0.47 Impact Factor
  • Resuscitation 11/2011; 97(7). DOI:10.1016/j.rcot.2011.08.189 · 3.96 Impact Factor
  • Neurochirurgie 09/2011; 57(s 4–6):260. DOI:10.1016/j.neuchi.2011.09.034 · 0.47 Impact Factor
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    ABSTRACT: Epidural motor cortex stimulation is an increasingly used method to control refractory neuropathic pain although its mechanisms of action remain poorly understood. Animal models are currently developed that allow reproducing the conditions of this neurosurgical approach and clarifying its mechanisms. In this study we validate a new stereotactic functional map of the cat motor cortex carried out in epidural conditions, thus allowing future experimentations that closely mimic the technique used in humans.
    Behavioural brain research 08/2011; 225(2):646-50. DOI:10.1016/j.bbr.2011.08.023 · 3.39 Impact Factor
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    ABSTRACT: Radiofrequency (RF) ablation is a minimally invasive technique often used percutaneously in the treatment of many conditions such as spasticity, pain, and osteoid osteoma. The purpose of this study was to assess the value of motor response threshold (MRT) as an indirect indicator of the RF generator's electrode to nerve distance, and to evaluate the effects of RF at various distances from a nervous structure. The L-5 nerve root was studied in 102 Sprague-Dawley rats (sham contralateral side). Motor response thresholds at 0, 2, 4, 5, and 6 mm from the nerve root were assessed before and after RF application for 2 minutes at 80° C on Days 0 and 7. Radiofrequency was applied 0, 2, 4, 5, and 6 mm away from L-5 and with the addition of interposed cortical bone. The effects of RF application on MRT were studied, and subsequent nerve injury was evaluated using light microscopy pathological examination. There is a significant correlation between MRT and the distance between the electrode tip and L-5, with MRT less than 0.5 V when the electrode was in direct contact with the root. Electrical and pathological changes following RF application were more pronounced at 0 mm, with worsening seen on Day 7. Radiofrequency at 2 and 4 mm produced fewer electrical and histological deleterious effects on the nerve on Days 0 and 7, with an obvious improvement on Day 7. At 5 mm, electrical and histological abnormalities were minimal on Day 0 and were fully reversible on Day 7. At 6 mm and with interposed cortical bone, MRT and pathological findings were unchanged on Days 0 and 7. The MRT proved to be a useful and reliable tool in decreasing nerve morbidity following RF ablation in animals and may be used in humans for the same purpose. It serves as an indirect indicator of the proximity of the RF generator's electrode tip to any adjacent motor nervous structure. A minimum safe distance of 5 mm between the electrode tip and the nerve is required to avoid irreversible nerve injury, unless a bony wall is interposed between them, thus serving as a nerve shield. In medical conditions that require RF ablation of the nerve, such as spasticity and pain, the MRT must be lower than 0.5 V. When a nerve lesion is to be avoided such as in cases of osteoid osteoma, an MRT higher than 2.5 V is considered safe, reflecting a distance greater than 5 mm.
    Journal of neurosurgery. Spine 06/2011; 15(3):285-91. DOI:10.3171/2011.4.SPINE10686 · 2.36 Impact Factor
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    ABSTRACT: The long-term outcome after lumbar microdiscectomy (LMD) may be affected by low back pain (LBP) and segmental instability, the determinants of which remain unclear. We sought to analyze the interaction between clinical, functional, and radiological variables and their impact on patient outcome. All patients who underwent LMD in 2004-2005 were invited to participate in this retrospective cohort study. Patients were re-evaluated clinically and radiologically after a three to five year follow-up. Forty-one of 97 eligible patients were enrolled. Twelve patients (29.3%) reported moderate-to-severe sciatica, 12 (29.3%) had moderate LBP, and 13 (31.7%) exhibited clinical evidence of segmental instability. Thirty-eight patients (92.7%) had minimal disability and 3 (7.3%) had moderate disability. Twenty-three patients (56.1%) were fully satisfied, while 18 (43.9%) had only partial satisfaction, having expected a better outcome. Thirty-three patients (80.5%) returned to full-time work. Median disc space collapse (DSC) was 20% (range 5-66%) and L4-L5 was particularly affected. Prevalence of Modic changes increased from 46.3% to 78% with type 2 predominance. Multivariate logistic regression analysis identified the following negative prognostic factors: female sex, young age, lack of regular exercise, and chronic preoperative LBP. There was no correlation between the course of Modic changes, DSC, and patient outcome. Although many patients may be symptomatic following LMD, significant disability and dissatisfaction are uncommon. Female sex, young age, lack of exercise, and chronic preoperative LBP may predict a worse outcome. Disc collapse is a universal finding, particularly at L4-L5. Neither DSC nor Modic changes seem to affect patient outcome.
    The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques 05/2011; 38(3):439-45. · 1.60 Impact Factor
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    ABSTRACT: Neuropathic pain (NP) may become refractory to conservative medical management, necessitating neurosurgical procedures in carefully selected cases. In this context, the functional neurosurgeon must have suitable knowledge of the disease he or she intends to treat, especially its pathophysiology. This latter factor has been studied thanks to advances in the functional exploration of NP, which will be detailed in this review. The study of the flexion reflex is a useful tool for clinical and pharmacological pain assessment and for exploring the mechanisms of pain at multiple levels. The main use of evoked potentials is to confirm clinical, or detect subclinical, dysfunction in peripheral and central somato-sensory pain pathways. LEP and SEP techniques are especially useful when used in combination, allowing the exploration of both pain and somato-sensory pathways. PET scans and fMRI documented rCBF increases to noxious stimuli. In patients with chronic NP, a decreased resting rCBF is observed in the contralateral thalamus, which may be reversed using analgesic procedures. Abnormal pain evoked by innocuous stimuli (allodynia) has been associated with amplification of the thalamic, insular and SII responses, concomitant to a paradoxical CBF decrease in ACC. Multiple PET studies showed that endogenous opioid secretion is very likely to occur as a reaction to pain. In addition, brain opioid receptors (OR) remain relatively untouched in peripheral NP, while a loss of ORs is most likely to occur in central NP, within the medial nociceptive pathways. PET receptor studies have also proved that antalgic Motor Cortex Stimulation (MCS), indicated in severe refractory NP, induces endogenous opioid secretion in key areas of the endogenous opioid system, which may explain one of the mechanisms of action of this procedure, since the secretion is proportional to the analgesic effect.
    Advances and technical standards in neurosurgery 01/2011; 37:25-63. DOI:10.1007/978-3-7091-0673-0_2
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    ABSTRACT: The natural history of Modic changes (MCs) in the lumbar spine is often marked by conversion from one type to another, but their course following lumbar discectomy remains unknown. The authors sought to study the impact of surgery on the natural history of these lesions. Forty-one patients treated with lumbar microdiscectomy between 2004 and 2005 were enrolled in this study and underwent clinical evaluation and repeat MR imaging after a median follow-up of 41 months (range 32-59 months). Preoperative and follow-up MR images were reviewed and the type, location, and extent of MCs at the operated level were recorded and compared. The study population consisted of 27 men and 14 women with a mean age of 54 years (range 24-78 years). During the follow-up period, the prevalence of MCs increased from 46.3% to 78%, and 26 patients (63.4%) had Type 2 lesions at the operated level. Of the 22 patients without MCs, 4 (18.2%) converted to Type 1 and 9 (40.9%) to Type 2. Of the 5 Type 1 lesions, 3 (60%) converted to Type 2, and 2 (40%) remained Type 1 but increased in size. In contrast, none of the 14 Type 2 changes converted to another type, although 10 (71.4%) increased in extent. There were no reverse conversions to Type 0. Following lumbar discectomy, most patients develop Type 2 changes at the operated level, possibly as a result of accelerated degeneration in the operated disc. Neither the preoperative presence of MCs nor their postoperative course appears to affect the clinical outcome.
    Journal of neurosurgery. Spine 11/2010; 13(5):562-7. DOI:10.3171/2010.5.SPINE09818 · 2.36 Impact Factor
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    ABSTRACT: Technical modalities for the evacuation of chronic subdural hematomas are still controversial. The Twist-Drill technique with closed-system drainage is becoming more widely used, but the influence of drainage duration on outcome has not been studied yet and therefore is still being debated. A prospective randomized study was conducted, comparing the results between two drainage durations. Forty-eight hours (Group I; n=35 patients) and 96 h (Group II; n=30 patients). The two groups had almost identical characteristics due to randomization. The mean volume of liquid drained was 120 ml in the first group and 285 ml in the second, a statistically significant difference. The rate of incomplete evacuation versus the rate of recurrence did not show any significant difference between Group I (5.7 % and 11.4 %, respectively) and Group II (3.3 % and 10 %, respectively). The rate of postoperative complications was 10.7 % in Group I but 26.9 % in Group II, with a respective 3.8 % and 11.4 % mortality rate, proving a statistically significant difference. Clinical improvement observed at discharge was 85.7 % and 84.6 % in Group I and Group II, respectively. With comparable recurrence and improvement rates, our study demonstrates that it is much more advantageous to remove the catheter at 48 h than leave it in for a longer duration. Not only is bed rest reduced, but the rate of morbidities is also significantly decreased.
    Neurochirurgie 02/2010; 56(1):23-7. DOI:10.1016/j.neuchi.2009.11.007 · 0.47 Impact Factor
  • J. Maarrawi, L. Garcia-Larrea
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    ABSTRACT: Les récepteurs opioїdes, dont la présence était suspectée depuis longtemps, ont pu être mis en évidence avec leurs ligands dans les années 1970 grâce à des études expérimentales in vitro. Ce n’est que vers 1985 que leur étude in vivo chez l’homme a été possible avec l’avènement de la tomographie par émission de positons (TEP), grâce au progrès concomitants de l’imagerie et de la radiochimie. Depuis, de multiples études TEP ont permis de clarifier la physiologie et la pathologie du système opioїde endogène humain dans de multiples conditions et pathologies. Ainsi, les études en douleur expérimentale tonique ont montré une activation du système opioїde dans l’amygdale ipsilatérale à la douleur, le noyau ventrolatéral du thalamus, le cortex insulaire et l’hypothalamus controlatéraux à la douleur et enfin dans le gyrus cingulaire antérieur et le cortex préfrontal bilatéralement. Cette activation est corrélée négativement avec la perception douloureuse. Ces études ont également montré une activation différentielle, dont l’importance et le sens varient en fonction du sexe. En matière de douleur nociceptive, il existe vraisemblablement une sécrétion accrue et réactionnelle d’opioїdes endogènes comme en témoigne la baisse de la fixation du radioligand aux récepteurs chez les patients atteints d’une pathologie douloureuse inflammatoire chronique (exemple: le rhumatisme inflammatoire). En matière de douleurs neuropathiques (DN), il existe également une sécrétion accrue d’opioїdes endogènes réactionnelle à la douleur. La distribution des récepteurs opioїdes encéphaliques ne souffre pas d’altération dans le type périphérique des DN, alors qu’on note une perte de ces récepteurs, latéralisée à l’hémisphère où siège la lésion causale de la douleur (controlatéral à la douleur clinique), et se localisant au niveau du système nociceptif médial dans le type central des DN. Ces différences dans le profil d’altération du système opioїde entre douleurs périphériques et centrales pourraient être à la base de leur sensibilité différentielle aux morphiniques exogènes. La stimulation du cortex moteur à visée antalgique pourrait induire une sécrétion d’opioїdes endogènes dans certaines structures clés du traitement de la douleur, réalisant ainsi un possiblemécanisme d’action de cette procédure. Les études réalisées jusqu’à présent ouvrent de multiples perspectives afin de clarifier le rôle de ce système dans de multiples pathologies du système nerveux, et d’évaluer le profil prédictif des anomalies TEP dans le développement de certaines DN et, peut-être, dans la réponse à certaines thérapeutiques onéreuses, comme la stimulation du cortex moteur. The existence of opioid receptors (OR) had long been suspected, but their demonstration in nervous tissue and the discovery of their natural ligands did not come until the 1970’s. By 1985, the study of brain OR was possible in vivo using Positron Emission Tomography (PET), thanks to technical advances in imaging and radiochemistry. Since then, multiple PET studies contributed to clarify the physiology and pathology of human endogenous opioid system in several conditions and pathologies. Thus, activation studies in tonic experimental pain have demonstrated opioid system activation in multiple opioid receptor bearing sites such as the amygdala, the ventrolateral thalamus, the insular cortex and hypothalamus, the anterior cingulate gyrus and the prefrontal cortex. Such activation is negatively correlated with the intensity of pain perception. Activation studies have also demonstrated sex-dependent and COMT (cathecol-O-methyltransferase)-dependent differences in the magnitude and direction of the activation of endogenous opioid systems. Endogenous opioid secretion is very likely to occur as a reaction to acute or chronic nociceptive pain, and PET studies have demonstrated a decrease in the binding of the exogenous ligand in patients suffering pain secondary to chronic inflammatory conditions like rheumatoid arthritis. In neuropathic pain (NP), endogenous reactive opioid secretion is also very likely as a global reaction to pain, but there are differences between central and peripheral causes of NP. Loss or inactivation of OR in the hemisphere containing the causal lesion (contralateral to clinical pain) has been demonstrated in central post-stroke pain, while no such lateralised loss seems to exists in peripheral NP. Difference in OR distribution abnormalities between peripheral and central types of NP might explain in part their differential response to exogenous opioids, which is better in peripheral NP. Motor Cortex Stimulation (MCS) for pain relief appears to induce endogenous opioid secretion in key areas of the endogenous opioid system, thus putatively explaining part of the mechanisms of action of this procedure. All these studies incite to the development of future investigations in order to clarify the role of the opioid system in various disorders of the nervous system, and, in chronic pain syndromes, to study the predictive potential of OR distribution abnormalities in the development of NP and in the clinical response of NP to aggressive therapeutic alternatives, like MCS. Mots clésDouleurs neuropathiques-Douleurs nociceptives-Système opioїde endogène-Tomographie par émission de positons-Stimulation du cortex moteur KeywordsNeuropathic pain-Nociceptive pain-Endogenous opioid system-Positron emission tomography-Motor cortex stimulation
    Douleur et Analgésie 12/2009; 22(4):248-260. DOI:10.1007/s11724-009-0167-y · 0.09 Impact Factor
  • Marc Sindou, Ibrahim Ibrahim, Joseph Maarrawi
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    ABSTRACT: Twist drill craniostomy with closed drainage system for 48-hour duration is an effective treatment of chronic subdural hematomas.
    Acta Neurochirurgica 09/2009; 152(3):545-6. DOI:10.1007/s00701-009-0489-9 · 1.79 Impact Factor
  • J. Maarrawi, L. Garcia-Larrea

Publication Stats

301 Citations
65.97 Total Impact Points


  • 2013
    • Lyon Neuroscience Research Center
      Lyons, Rhône-Alpes, France
  • 2007–2013
    • Saint Joseph University, Lebanon
      Beyrouth, Beyrouth, Lebanon
    • HCL
      Noida, Uttar Pradesh, India
  • 2006–2010
    • Claude Bernard University Lyon 1
      Villeurbanne, Rhône-Alpes, France
  • 2005
    • University of Malaga
      • Area of Physiology
      Málaga, Andalusia, Spain
  • 2003–2005
    • CHU de Lyon - Hôpital Neurologique et Neurochirurgical Pierre Wertheimer
      Lyons, Rhône-Alpes, France