O. Hamel

Centre Hospitalier Universitaire Rouen, Rouen, Upper Normandy, France

Are you O. Hamel?

Claim your profile

Publications (112)73.32 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The Brindley procedure, used since the 1980s, consists of implantation of a stimulator for sacral anterior root stimulation combined with a posterior sacral rhizotomy to enable micturition. Patients suitable for the procedure are patients with detrusor overactivity and a complete spinal cord lesion with intact sacral reflexes. S2 to S4 posterior sacral rhizotomy abolishes sacral hyperreflexia and may lead to decreased urethral closure pressure and loss of reflex adaptation of continence, leading to stress incontinence.
    Neurourology and Urodynamics 11/2014; · 2.67 Impact Factor
  • Morphologie 09/2014; 98(322):97.
  • Intensive care medicine. 08/2014;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Minor head trauma is a common cause for pediatric emergency department visits. In 2009, the Pediatric Emergency Care Applied Research Network (PECARN) published a clinical prediction rule for identifying children at very low risk of clinically important traumatic brain injuries (ciTBI) and for reducing CT use because of malignancy induced by ionizing radiation. The prediction rule for ciTBI was derived and validated on 42,412 children in a prospective cohort study. The Société Française de Médecine d'Urgence (French Emergency Medicine Society) and the Groupe Francophone de Réanimation et Urgences Pédiatriques (French-Language Pediatric Emergency Care Group) recommend this algorithm for the management of children after minor head trauma. Based on clinical variables (history, symptoms, and physical examination findings), the algorithm assists in medical decision-making: CT scan, hospitalization for observation or discharge, according to three levels of ciTBI risk (high, intermediate, or low risk). The prediction rule sensitivity for children younger than 2 years is 100 % [86.3-100] and for those aged 2 years and older it is 96.8 % [89-99.6]. Our aim is to present these new recommendations for the management of children after minor head trauma.
    Archives de pediatrie : organe officiel de la Societe francaise de pediatrie. 06/2014;
  • Annals of Physical and Rehabilitation Medicine 05/2014; 57:e242-e243.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Symptomatic vertebral hemangiomas during pregnancy are rare, as only 27 cases have been reported in the literature since 1948. However, symptomatic vertebral hemangiomas can be responsible for spinal cord compression, in which case they constitute a medical emergency, which raises management difficulties in the context of pregnancy. Pregnancy is a known factor responsible for deterioration of these vascular tumors. In this paper, the authors report 2 clinical cases of symptomatic vertebral hemangiomas during pregnancy, including 1 case of spontaneous fracture that has never been previously reported in the literature. The authors then present a brief review of the literature to discuss emergency management of this condition. The first case was a 28-year-old woman at 35 weeks of gestation, who presented with paraparesis. Spinal cord MRI demonstrated a vertebral hemangioma invading the body and posterior arch of T-3 with posterior epidural extension. Laminectomy and vertebroplasty were performed after cesarean section, allowing neurological recovery. The second case involved a 35-year-old woman who presented with spontaneous fracture of T-7 at 36 weeks of gestation, revealing a vertebral hemangioma with no neurological deficit, but it was responsible for pain and local instability. Treatment consisted of postpartum posterior interbody fusion. With a clinical and radiological follow-up of 2 years, no complications and no modification of the hemangiomas were observed. A review of the literature reveals discordant management of these rare cases, which is why the treatment course must be decided by a multidisciplinary team as a function of fetal gestational age and maternal neurological features.
    Journal of neurosurgery. Spine 03/2014; · 1.61 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Background. Decompressive craniectomy can be proposed in the management of severe traumatic brain injury. Current studies report mixed results, preventing any clear conclusions on the place of decompressive craniectomy in traumatology. Methods. The objective of this retrospective study was to evaluate the results of all decompressive craniectomies performed between 2005 and 2011 for refractory intracranial hypertension after severe traumatic brain injury. Sixty patients were included. Clinical parameters (Glasgow scale, pupillary examination) and radiological findings (Marshall CT scale) were analysed. Complications, clinical outcome, and early and long-term Glasgow Outcome Scale (GOS) were evaluated after surgery. Finally, the predictive value of preoperative parameters to guide the clinician's decision to perform craniectomy was studied. Results. Craniectomy was unilateral in 58 cases and the mean bone flap area was 100 cm(2). Surgical complications were observed in 6.7% of cases. Mean followup was 30 months and a favourable outcome was obtained in 50% of cases. The initial Glasgow Scale was the only statistically significant predictive factor for long-term outcome. Conclusion. Despite the discordant results in the literature, this study demonstrates that decompressive craniectomy is useful for the management of refractory intracranial hypertension after severe traumatic brain injury.
    The Scientific World Journal 01/2014; 2014:207585. · 1.73 Impact Factor
  • Source
    The Scientific World Journal 01/2014; · 1.73 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Introduction. Spasticity is a disabling symptom resulting from reorganization of spinal reflexes no longer inhibited by supraspinal control. Several studies have demonstrated interest in repetitive transcranial magnetic stimulation in spastic patients. We conducted a prospective, randomized, double-blind crossover study on five spastic hemiparetic patients to determine whether this type of stimulation of the premotor cortex can provide a clinical benefit. Material and Methods. Two stimulation frequencies (1 Hz and 10 Hz) were tested versus placebo. Patients were assessed clinically, by quantitative analysis of walking and measurement of neuromechanical parameters (H and T reflexes, musculoarticular stiffness of the ankle). Results. No change was observed after placebo and 10 Hz protocols. Clinical parameters were not significantly modified after 1 Hz stimulation, apart from a tendency towards improved recruitment of antagonist muscles on the Fügl-Meyer scale. Only cadence and recurvatum were significantly modified on quantitative analysis of walking. Neuromechanical parameters were modified with significant decreases in H max⁡ /M max⁡ and T/M max⁡ ratios and stiffness indices 9 days or 31 days after initiation of TMS. Conclusion. This preliminary study supports the efficacy of low-frequency TMS to reduce reflex excitability and stiffness of ankle plantar flexors, while clinical signs of spasticity were not significantly modified.
    TheScientificWorldJournal. 01/2014; 2014:389350.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Minor head trauma is a common cause for pediatric emergency department visits. In 2009, the Pediatric Emergency Care Applied Research Network (PECARN) published a clinical prediction rule for identifying children at very low risk of clinically important traumatic brain injuries (ciTBI) and for reducing CT use because of malignancy induced by ionizing radiation. The prediction rule for ciTBI was derived and validated on 42,412 children in a prospective cohort study. The Société Française de Médecine d’Urgence (French Emergency Medicine Society) and the Groupe Francophone de Réanimation et Urgences Pédiatriques (French-Language Pediatric Emergency Care Group) recommend this algorithm for the management of children after minor head trauma. Based on clinical variables (history, symptoms, and physical examination findings), the algorithm assists in medical decision-making: CT scan, hospitalization for observation or discharge, according to three levels of ciTBI risk (high, intermediate, or low risk). The prediction rule sensitivity for children younger than 2 years is 100 % [86.3–100] and for those aged 2 years and older it is 96.8 % [89–99.6]. Our aim is to present these new recommendations for the management of children after minor head trauma.
    Archives de Pédiatrie. 01/2014;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Thirty percent of patients with pudendal neuralgia due to pudendal nerve entrapment obtain little or no relief from nerve decompression surgery. The objective was to describe the efficacy of spinal cord stimulation of the conus medullaris in patients with refractory pudendal neuralgia. This prospective study, conducted by two centers in the same university city, described the results obtained on perineal pain and functional disability in all patients with an implanted conus medullaris stimulation electrode for the treatment of refractory pudendal neuralgia. Twenty-seven consecutive patients were included by a multidisciplinary pelvis and perineal pain clinic between May 2011 and July 2012. Mean follow-up was 15 months. The intervention was an insertion of a stimulation electrode was followed by a test period (lasting an average of 13 days) before deciding on permanent electrode implantation. Maximum and average perineal pain scores and the pain-free sitting time were initially compared during the test and in the long-term (paired t-test). The estimated percent improvement (EPI) was evaluated in the long-term. Twenty of the 27 patients were considered to be responders to spinal cord stimulation and 100% of implanted patients remained long-term responders (mean tripling of sitting time, and mean EPI of 55.5%). Spinal cord stimulation of the conus medullaris is a safe and effective technique for long-term treatment of refractory pudendal neuralgia. Routine use of this technique, which has never been previously reported in the literature in this type of patient, must now be validated by a larger scale study. Neurourol. Urodynam. © 2013 Wiley Periodicals, Inc.
    Neurourology and Urodynamics 11/2013; · 2.67 Impact Factor
  • Annals of Physical and Rehabilitation Medicine 10/2013; 56, Supplement 1:e76.
  • Morphologie 10/2013; 97(s 318–319):72.
  • Morphologie 10/2013; 97(s 318–319):88–89.
  • [Show abstract] [Hide abstract]
    ABSTRACT: The intervertebral disc is a complex anatomical structure consisting of a near central gelatinous region, called nucleus pulposus (NP), surrounded by an annular ligament-type structure, the annulus fibrosis, and separated from vertebrae by cartilaginous endplates, which constitute the main nutritive pathway of this core. The cellular and biochemical characteristics of these structures determine the biomechanical properties. Nucleus pulposus distributes pressures applied to the intervertebral disc, thereby tensioning the annulus fibers. The major constraints faced by the intervertebral disc involve multiple phenomena like viscoelastic behavior (playing quickly), but also slower like corporeo-discal exchange related to the porosity of the endplates.
    Revue du Rhumatisme Monographies 09/2013; 80(4):204–209.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Recent improvements of our understanding of the physiopathological processes of disc degeneration has made possible to consider with interest the regenerative medicine strategies to restore the intervertebral disc (IVD) function. These strategies include cell therapy and tissue engineering that could repair disc integrity by appropriate cells associated or not with a scaffolding biomaterials. Several options can be considered concerning cell types but also biomaterials. Studies in animal and human seem to confirm the feasibility of such an approach. However, unresolved issues remain including cell and biomaterial types to restore a functional nucleopulpogenic extracellular matrix (ECM). To date, stem cells (MSC and induced pluripotent stem cells iPS) and hydrogel family are well acknowledged as the ideal candidates regarding their ability to differentiate into an appropriate cell type and their hyperhydration composition similar to that of intervertebral disc ECM, respectively. Future work should allow to consider regenerative medicine as a breakthrough innovation in the management of low back pain patients. After a brief reminder of the general principles of regenerative medicine and its relevance to treat degenerative disc disease, cell therapy and tissue engineering are discussed. A state of the art is then given before discussing the remaining challenges prior to the transposition to humans.
    Revue du Rhumatisme 09/2013;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Lumbar intervertebral discs (IVD) are highly prone to degenerate as early as the skeletal maturity is achieved. This degeneration could explain about 40% of the low back pain cases in humans. Despite the efficiency of pain-relieving treatments, the scientific community seeks to develop innovative therapeutic approaches to limit the use of invasive surgical procedures (spine fusion and arthroplasty). As a prerequisite to the development of these therapeutic strategies, we first have to improve our fundamental knowledge on IVD physiopathology. Recently, several studies have demonstrated that the phenotype of Nucleus pulposus (NP) cells was singular and quite distinct from that of articular chondrocytes. In parallel, recent studies dealing with NP cell development and origin as well as their role in intervertebral tissue homesotasis allowed to gain new insights into the complex mechanisms governing disc degeneration. This review summarizes the actual knowledge on IVD physiology and on the complex cell-mediated processes of IVD degeneration that has recently led the scientific community to explore new biotherapeutic strategies.
    Revue du Rhumatisme 09/2013;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Lumbar intervertebral discs (IVDs) are prone to degeneration upon skeletal maturity. In fact, this process could explain approximately 40% of the cases of low back pain in humans. Despite the efficiency of pain-relieving treatments, the scientific community seeks to develop innovative therapeutic approaches that might limit the use of invasive surgical procedures (e.g., spine fusion and arthroplasty). As a prerequisite to the development of these strategies, we must improve our fundamental knowledge regarding IVD pathophysiology. Recently, several studies have demonstrated that there is a singular phenotype associated with Nucleus pulposus (NP) cells, which is distinct from that of articular chondrocytes. In parallel, recent studies concerning the origin and development of NP cells, as well as their role in intervertebral tissue homeostasis, have yielded new insights into the complex mechanisms involved in disc degeneration. This review summarizes our current understanding of IVD physiology and the complex cell-mediated processes that contribute to IVD degeneration. Collectively, these recent advances could inspire the scientific community to explore new biotherapeutic strategies.
    Joint, bone, spine: revue du rhumatisme 08/2013; · 2.25 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Occipitalization of the atlas is the most common malformation of the craniovertebral junction. It can be diagnosed on lateral teleradiography and its finding imposes screening for associated atlantoaxial instability. In case of instability, brisk movements of the cervical spine during surgery may result in compression and distortion of the spinal chord and vertebro-basilar vascular system. An 18 year-old female patient was referred to our department for facial dysmorphosis and extraction of the third molars. A lateral teleradiography revealed an occipitalization of the atlas and the fusion of the second and third cervical vertebral body. Further pre-operative investigations allowed ruling out any joint instability or associated craniovertebral junction malformations. Occipitalization of the atlas is not usually well-known by maxillofacial surgeons. It may be diagnosed with a lateral teleradiography. Its diagnosis imposes screening for other spinal malformations (spinal fusion, hemivertebra, spina bifida occulta). The major risk is compression and distortion of the spinal chord and vertebro-basilar vascular system, during surgery or anesthesia.
    Revue de stomatologie, de chirurgie maxillo-faciale et de chirurgie orale. 06/2013; 114(3):187-91.
  • [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND: The neuromechanical consequences of tibial neurotomy have not been extensively studied. METHODS: Fifteen patients were evaluated before and after selective tibial neurotomy (after 2 months and after 15 months) by means of clinical, neurophysiological [tendon (T) reflexes, Hoffmann (H) reflexes and maximum motor response, Mmax] and mechanical parameters (passive stiffness of plantar flexors at the ankle). The neurotomy concerned the soleus (100 % of cases), gastrocnemius (20 % of cases), posterior tibial (60 % of cases) and flexor digitorum longus (47 % of cases) nerves. RESULTS: Neurotomy provided more than 90 % improvement of clinical spasticity scores, 20 % improvement of walking scores and the angle of passive dorsiflexion (APDF) of the ankle (mean angle: 7°), temporary reduction of the soleus Mmax (18 % at 2 months with return to the preoperative value at 15 months), and lasting reduction of the soleus Hmax/Mmax (68 % at 2 months, 78 % at 15 months) and T/Mmax (84 % at 2 months, 80 % at 15 months). M and H responses of the gastrocnemius (whether or not they were included in the neurotomy) were not modified, while T/Mmax decreased to the same degree as for soleus. Passive stiffness was lastingly decreased from 64.0 Nm/rad to 49.0 Nm/rad (2 months) and 49.5 Nm/rad (15 months). CONCLUSION: Selective tibial neurotomy of the soleus nerve induces long-term reduction of reflex hyperexcitability and passive stiffness of plantar flexors in spastic patients, with no lasting impairment of motor efferents. In parallel, it modifies the tendon reflexes of synergistic muscles (gastrocnemius) not concerned by the neurotomy.
    Acta Neurochirurgica 05/2013; · 1.55 Impact Factor

Publication Stats

237 Citations
73.32 Total Impact Points

Institutions

  • 2013
    • Centre Hospitalier Universitaire Rouen
      • Service d'Urologie
      Rouen, Upper Normandy, France
  • 2003–2013
    • University of Nantes
      • Faculté de Médecine
      Naoned, Pays de la Loire, France
  • 2002–2012
    • Centre Hospitalier Universitaire de Nantes
      • • Service de neurotraumatologie
      • • Clinique de chirurgie digestive et endocrinienne
      Naoned, Pays de la Loire, France
  • 2008
    • Hôtel-Dieu de Paris – Hôpitaux universitaires Paris Centre
      Lutetia Parisorum, Île-de-France, France
  • 2005
    • Centre Catherine de Sienne
      Naoned, Pays de la Loire, France
    • Centre Hospitalier de la Côte Basque
      Bayona, Aquitaine, France