Publications (15)33.3 Total impact
-
Article: Paraganglioma of the sacral spinal canal.
[show abstract] [hide abstract]
ABSTRACT: Paragangliomas are tumors arising in the paraganglia. Involvement of the spine is less common, and usually takes the form of intradural compression of the cauda equina. We report here a case of a 60-year-old man with recurrent and progressive pain of his sacral and perineal area, accompanied by occasional rod and perineal hypoesthesia on admission. He underwent laminectomies of the vertebral bodies S1 and S2, and an en bloc resection of the tumor. Postoperative histopathological examination revealed a paraganglioma. Postoperative staging showed no pathological abnormalities, and no tumor recurrence after one year. Even though rare, the paraganglioma of the sacral spinal canal should be considered in the differential diagnosis of tumors occurring in the spine.Neurosciences 07/2011; 16(3):270-2. · 0.12 Impact Factor -
Article: Natural history of supratentorial hemangioblastomas in von Hippel-Lindau disease.
[show abstract] [hide abstract]
ABSTRACT: Supratentorial hemangioblastomas are rare lesions, occurring either sporadically or in von Hippel-Lindau disease. Following recent advances in our understanding of the natural history of von Hippel-Lindau-associated cerebellar and spinal hemangioblastomas, we conducted a study of the natural history of supratentorial hemangioblastomas in von Hippel-Lindau disease. We reviewed a series of 18 supratentorial hemangioblastomas in 13 patients with von Hippel-Lindau disease. Clinical, genetic, and serial imaging data and operative records were analyzed. Hemangioblastomas were most commonly seen in the temporal lobe. Only 6 tumors had a cyst at diagnosis or during follow-up, and only 6 patients had associated symptoms at presentation or during follow-up. The most frequent clinical presentations were intracranial hypertension and visual loss. Of 14 tumors with documented serial imaging, 13 demonstrated tumor growth. Rates and patterns of tumor growth were unique to each patient. The mechanism of cyst formation described in other locations was also demonstrated in the supratentorial region. Patterns of peritumoral edema and rate of cyst formation seemed to be influenced by the presence of anatomic barriers. Germline VHL mutation was identified in all patients, but no specific genotype-phenotype correlation was found, although a familial predisposition is suggested. This series illustrates the wide variation in tumor locations, patterns of growth, and edema progression seen in supratentorial hemangioblastomas and adds to our knowledge of the natural history of hemangioblastomas.Neurosurgery 09/2010; 67(3):577-87; discussion 587. · 2.79 Impact Factor -
Article: Natural History of Supratentorial Hemangioblastomas in von Hippel-Lindau Disease
[show abstract] [hide abstract]
ABSTRACT: BACKGROUND: Supratentorial hemangioblastomas are rare lesions, occurring either sporadically or in von Hippel-Lindau disease. OBJECTIVE: Following recent advances in our understanding of the natural history of von Hippel-Lindau–associated cerebellar and spinal hemangioblastomas, we conducted a study of the natural history of supratentorial hemangioblastomas in von Hippel-Lindau disease. METHODS: We reviewed a series of 18 supratentorial hemangioblastomas in 13 patients with von Hippel-Lindau disease. Clinical, genetic, and serial imaging data and operative records were analyzed. RESULTS: Hemangioblastomas were most commonly seen in the temporal lobe. Only 6 tumors had a cyst at diagnosis or during follow-up, and only 6 patients had associated symptoms at presentation or during follow-up. The most frequent clinical presentations were intracranial hypertension and visual loss. Of 14 tumors with documented serial imaging, 13 demonstrated tumor growth. Rates and patterns of tumor growth were unique to each patient. The mechanism of cyst formation described in other locations was also demonstrated in the supratentorial region. Patterns of peritumoral edema and rate of cyst formation seemed to be influenced by the presence of anatomic barriers. Germline VHL mutation was identified in all patients, but no specific genotype-phenotype correlation was found, although a familial predisposition is suggested. CONCLUSION: This series illustrates the wide variation in tumor locations, patterns of growth, and edema progression seen in supratentorial hemangioblastomas and adds to our knowledge of the natural history of hemangioblastomas.Neurosurgery 08/2010; 67(3):577–587. · 2.79 Impact Factor -
Article: Decompressive craniectomy in children with nontraumatic refractory high intracranial pressure. Clinical article.
[show abstract] [hide abstract]
ABSTRACT: In this study, the authors investigated the clinical efficacy of decompressive craniectomy treatments for nontraumatic intracranial hypertension in children. Seven patients with nontraumatic refractory high intracranial pressure (ICP) were enrolled in the study between 1995 and 2005; there were 2 boys and 5 girls with a mean age of 9 years (range 4-14). Decompressive craniectomy was performed in all patients after standard medical therapy had proven insufficient and ICP remained > 50 mm Hg. All patients had a Glasgow Coma Scale score < 8 at admission and a mean Pediatric Risk of Mortality Scale score of 20 (range 10-27). One patient died of persistent high ICP and circulatory failure 48 hours after surgery. Six months later, according to their Glasgow Outcome Scale scores, 3 patients had adequate recoveries, 2 patients recovered with moderate disabilities, and 1 patient had severe disabilities. According to the Pediatric Overall Performance Category Scale, 4 patients received a score of 2 (mild disability), 1 a score of 3 (moderate disability), and 1 a score of 4 (severe disability). Five patients returned to school and normal life. The authors found decompressive craniectomy to be an effective and lifesaving technique in children. This procedure should be included in the arsenal of treatments for nontraumatic intracranial hypertension.Journal of Neurosurgery Pediatrics 02/2009; 3(1):66-9. · 1.53 Impact Factor -
Article: Multiple lumbar roots neurotizations with the lower intercostal nerves. Preliminary clinical and electrophysiological results in a sheep model.
[show abstract] [hide abstract]
ABSTRACT: Neurotization of lumbar roots with lower intercostal nerves is a potential way to treat neurological deficits after spinal cord injury. The anatomical feasibility of such neurotizations in humans has already been reported. We propose to assess axonal regrowth after intercostal to lumbar neurotization in a sheep model. Ten sheep had a left T11-L2, T12-L3, and T13-L4 neurotization. In 5 sheep, a L1 level left hemisection of the spinal cord was performed. The sheep had clinical and electrophysiological monitoring with a 6 mon follow-up. A flaccid paralysis with clinical asymmetry of the left abdominal wall was noted three months after surgery. This asymmetry improved in all the cases at the 6 mon follow-up. Motor potentials were detected without difficulty for the 3 neurotized nerves (L2, L3, and L4) in 5 sheep. In another sheep, motor potentials of the L3 root remained undetected. Eight sheep had postoperative complications responsible for the animals' death in 5 cases. The current study demonstrates the technical feasibility of intercosto-lumbar neurotizations in a sheep model. We proved in all the animals--except in the case of 1 neurotized root--the ability of motor axon to regenerate through neurotization area down to the muscular effectors; however, we noted a high rate of postoperative complications in this animal model.Journal of Surgical Research 12/2007; 149(2):199-205. · 2.25 Impact Factor -
Article: The paraspinal splitting approach: a possible approach to perform multiple intercosto-lumbar neurotizations: an anatomic study.
[show abstract] [hide abstract]
ABSTRACT: Descriptive anatomy. OBJECTIVE.: To describe the anatomy associated with the extensive transmuscular paraspinal approach required to perform multiple intercosto-lumbar neurotizations. Neurotization of lumbar roots using lower intercostal nerves is a potential method of treating neurologic deficits after spinal cord injury. It appeared to us that the paraspinal splitting approach was potentially an optimal method to perform intercostal nerve harvesting, rerouting, and intercosto-lumbar neurotizations. Ninth, 10th, and 11th intercostal nerve harvesting and rerouting down to L2, L3, and L4 roots were performed on 50 cadavers. The descriptive anatomy and topographic landmarks are reported. The mean total length of intercostal nerve harvested was 17.96 (range, 10-27) cm for the 9th intercostal nerve, 17.14 cm (range, 10-20) for the 10th intercostal nerve and 15.94 cm (range, 10-25) for the 11th intercostal nerve. The length of harvested nerve was not correlated to the size of the trunk. The length of harvested nerve was sufficient to perform lumbar roots neurotizations in the 300 cases of nerve harvesting. Multiple lumbar roots neurotizations with lower intercostal nerves already have been proposed by other authors. In this strategy, the use of the spinal cord and intercostal nerves above the spinal cord lesion avoids the axonal regrowth required via the injured central nervous system. Rerouting intercostals nerves down to the lumbar roots at their exit from the intervertebral foraminae is less invasive that the same procedure performed down to the vertebral canal at the level of the cauda equina as we used in previous protocols. Our anatomic study confirms the advantage of the paraspinal sacrospinalis splitting approach in multiple intercosto-lumbar neurotizations. The approach is quick and easy and allows a good exposure of the nerve roots at the thoracic and lumbar levels. The L2, L3, and L4 roots could be satisfactorily neurotized with this procedure.Spine 11/2007; 32(22):E631-4. · 2.08 Impact Factor -
Article: Pseudotumoral presentation of a cervical extracranial vertebral artery aneurysm in neurofibromatosis type 1: case report.
[show abstract] [hide abstract]
ABSTRACT: Neurofibromatosis Type 1 (NF1) is known to be associated with vascular lesions. Association with an extracranial vertebral artery aneurysm is very rare. We report the case of such an aneurysm mimicking a cervical neurofibroma in NF1. An 18-year-old woman with previously diagnosed NF1 presented with a C6 radiculopathy. There were no clinical features suggesting a vascular origin for the lesion. The computed tomographic and standard magnetic resonance imaging scans showed a C5-C6 contrast-enhancing lesion responsible for bony erosion. Subsequent, magnetic resonance angiography and digital subtraction angiography diagnosed the lesion as a C5-C6 vertebral artery aneurysm. The lesion was treated by endovascular occlusion of both the aneurysm and the parent vertebral artery with an initial immediate disappearance of the pain. This case serves as a reminder of the importance of ruling out a vertebral artery aneurysm with angiography when managing cervical lesions in patients with NF1.Neurosurgery 10/2007; 61(3):E658; discussion E658. · 2.79 Impact Factor -
Article: Diffusion tensor magnetic resonance imaging and fiber tracking in spinal cord lesions: current and future indications.
[show abstract] [hide abstract]
ABSTRACT: Diffusion-weighted imaging and fractional anisotropy may be more sensitive than other conventional magnetic resonance imaging techniques to detect, characterize, and map the extent of spinal cord lesions. Fiber tracking offers the possibility of visualizing the integrity of white matter tracts surrounding some lesions, and this information may help in formulating a differential diagnosis and in planning biopsies or resection. Fractional anisotropy measurements may also play a role in predicting the outcome of patients who have spinal cord lesions. In this article, we address several conditions in which diffusion-weighted imaging and fiber tracking is known to be useful and speculate on others in which we believe these techniques will be useful in the near future.Neuroimaging Clinics of North America 03/2007; 17(1):137-47. · 1.51 Impact Factor -
Article: The feasibility of detecting motor and sensory potentials in a sheep model.
[show abstract] [hide abstract]
ABSTRACT: To investigate the characteristics of motor, sensory and sensory-evoked potentials (SEPs) of thoracic and lumbar roots, and demonstrate the feasibility of assessing axonal regrowth after the neurotization procedure in a sheep model. Six adult sheep were anaesthetized and placed in a sternal position. The thoracic and lumbar roots from T11 to L5 were identified at their emergence from the vertebral foramen and stimulated. Motor and sensory responses were monitored. Thoracic and lumbar roots were easily identified in all cases. Motor potentials were detected for each stimulated nerve without difficulty. The amplitudes were quite variable, ranging from 100 to 5300 microV. Sensory and SEPs were satisfactorily recorded in only three of the six animals. Sensory amplitudes also varied greatly, ranging from 25 to 120 microV. In three cases, SEPs could not be identified due to motor artefacts. The motor pathway after axonal regrowth in neurotized lumbar roots might easily be explored by proximal electric stimulation of the root, close to the sutured area. Detection of sensory and spinal cord evoked potentials might be improved by the use of curve summation techniques. Specific axonal tracing holds promise of being a useful technique for examining sensory and motor pathway recovery after neurotization in the sheep model.Laboratory Animals 11/2006; 40(4):469-73. · 1.21 Impact Factor -
Article: Anatomical feasibility of using the ninth, 10th, and 11th intercostal nerves for the treatment of neurological deficits after damage to the spinal cord.
[show abstract] [hide abstract]
ABSTRACT: The topographic anatomy of the lower intercostal nerves is less well known than that of the upper ones, except for the 12th intercostal nerve. It is possible to use the lower intercostal nerves to perform a neurotization of the lumbar roots. The authors studied the anatomy of the ninth, 10th, and 11th intercostal nerves to obtain descriptive and topographic anatomical data to aid in establishing optimal conditions for harvesting. The ninth, 10th, and 11th intercostal nerves of 50 cadavers were dissected. The proximal part of the nerve in the posterior intercostal space (ISC) was exposed through a posterior approach. The lateral ICS was exposed through a lateral approach, under the latissimus dorsi, which made it possible to harvest the intercostal nerves using a stripping technique. A histological study was conducted on 10 pigs to evaluate the risk of nerve lesions during the stripping procedure. The proximal course of the nerve in the posterior ICS was the same in all cases. The mean total length of the intercostal nerves harvested was 17.96 cm for the ninth, 17.14 cm for the 10th, and 15.94 cm for the 11th intercostal nerve. The harvested nerve length was sufficient in 297 of the 300 cases to perform lumbar root neurotization. The histological study showed no difference between the "open" and the "stripping" techniques regarding the risk of histological lesions in harvested nerves.Journal of Neurosurgery Spine 04/2006; 4(3):225-32. · 1.53 Impact Factor -
Article: Reinnervation of hind limb extremity after lumbar dorsal root ganglion injury.
[show abstract] [hide abstract]
ABSTRACT: Loss of dorsal root ganglion neuron, or injury to dorsal roots, induces permanent somatosensory defect without therapeutic option. We explored an approach to restoring hind limb somatosensory innervation after elimination of L4, L5 and L6 dorsal root ganglion neurons in rats. Somatosensory pathways were reconstructed by connecting L4, L5 and L6 lumbar dorsal roots to T10, T11 and T12 intercostal nerves, respectively, thus allowing elongation of thoracic ganglion neuron peripheral axons into the sciatic nerve. Connection of thoracic dorsal root ganglion neurons to peripheral tissues was documented 4 and 7 months after injury. Myelinated and unmyelinated fibers regrew in the sciatic nerve. Nerve terminations expressing calcitonin-gene-related-peptide colonized the footpad skin. Retrograde tracing showed that T10, T11 and T12 dorsal root ganglion neurons expressing calcitonin-gene-related-peptide or the neurofilament RT97 projected axons to the sciatic nerve and the footpad skin. Recording of somatosensory evoked potentials in the upper spinal cord indicated connection between the sciatic nerve and the central nervous system. Hind limb retraction in response to nociceptive stimulation of the reinnervated footpads and reversion of skin lesions suggested partial recovery of sensory function. Proprioceptive defects persisted. Delayed somatosensory reinnervation of the hind limb after destruction of lumbar dorsal root neurons in rats indicates potential approaches to reduce chronic disability after severe injury to somatosensory pathways.Experimental Neurology 01/2006; 196(2):401-12. · 4.70 Impact Factor -
Article: Charcot spine: a complication of medullary arteriovenous malformation. Case illustration.
Journal of Neurosurgery Spine 08/2004; 1(1):141. · 1.53 Impact Factor -
Article: Efficient reinnervation of hindlimb muscles by thoracic motor neurons after nerve cross-anastomosis in rats.
[show abstract] [hide abstract]
ABSTRACT: Peripheral motor axons can regenerate through motor endoneurial tubes of foreign nerves to reinnervate different target muscles. This regenerative capacity has been brought to clinical applications for restorative surgery after nerve or root injury. In this study the authors explore the extent to which nerve cross-anastomosis between lower intercostal nerves and lumbar ventral roots would be effective in inducing reinnervation of paralyzed hindlimb muscles after spinal cord hemisection at the thoracolumbar boundary in rats. The proximal extremities of sectioned intercostal nerves T10-12 were surgically connected to the distal extremities of sectioned ipsilateral lumbar ventral roots L3-5, respectively. Motor activity reappeared 2 months postsurgery; however, locomotion was not restored and inappropriate motor patterns persisted at 9 months postsurgery. At that time, data from electrophysiological and histological studies and horseradish peroxidase retrograde labeling demonstrated efficient regrowth of thoracic motor neuron axons that reached hindlimb muscles. They also revealed a persistent maturation defect of regrown fibers, as shown by size heterogeneity and presumable extensive axonal branching. These features are consistent with reduced neural activity subsequent to continuing inappropriate motor patterns. These results indicate that cross-anastomosis of intercostal nerves with lumbar ventral roots allows efficient reinnervation of paralyzed hindlimb muscles after spinal cord hemisection in rats. Stimulating the reorganization of the neuronal circuitry in the central nervous system by locomotion training or other methods would presumably result in both functional and anatomical improvements. This experimental setting provides a convenient animal model to investigate these processes.Journal of Neurosurgery 12/2003; 99(5):879-85. · 2.96 Impact Factor -
Article: Classification of spinal cord arteriovenous shunts: proposal for a reappraisal--the Bicêtre experience with 155 consecutive patients treated between 1981 and 1999.
[show abstract] [hide abstract]
ABSTRACT: Spinal cord arteriovenous shunts (SCAVSs) are currently classified according to their morphological features. Certain shunts cannot be fully integrated into the predetermined categories that are usually described, however. Can these classifications be reevaluated on the basis of recent anatomic, biological, and genetic advances? We reviewed the clinical and radiological files for 155 SCAVSs that were treated at Hôpital Bicêtre between 1981 and 1999. The lesions were examined with respect to their number (single or multiple), their primary architectural type (nidus or fistula), and their possible links with associated metameric lesions. All SCAVSs were either arteriovenous malformations or fistulae, with the latter being either micro- or macrofistulae. All SCAVSs corresponded to three categories, i.e., genetic hereditary lesions (macrofistulae and hereditary hemorrhagic telangiectasia), genetic nonhereditary lesions (all of which were multiple lesions with metameric or myelomeric associations), and single lesions (which could represent incomplete presentations of one of the previous groups). Of the SCAVSs in our series, 81% were single lesions and 19% were multiple; among these, 59% were true intradural shunts with metameric features. Ten cases of Cobb syndrome, three cases of Klippel-Trenaunay syndrome, and two cases of Parkes-Weber syndrome, all with associated cord lesions, were observed. Nineteen percent of SCAVSs were fistulae; 23% of those were macrofistulae, of which 83% were related to Rendu-Osler-Weber disease. It seems legitimate to propose a categorization that takes into consideration a primary malformation (nidus or fistula) that evolves with time and in which angioarchitectural changes occur. Recognition of the factors originally responsible for the shunt (e.g., genetic hereditary or genetic nonhereditary) allows a different classification of SCAVSs.Neurosurgery 09/2002; 51(2):374-9; discussion 379-80. · 2.79 Impact Factor -
Article: Regeneration of primary sensory axons into the adult rat spinal cord via a peripheral nerve graft bridging the lumbar dorsal roots to the dorsal column.
[show abstract] [hide abstract]
ABSTRACT: This study investigated the feasibility of using a peripheral nerve autograft (NAG) to promote and guide regeneration of sensory axons from the caudal lumbar dorsal roots to the rostral dorsal column following a lower thoracic cordotomy in adult rats. After a left hemicordotomy at the T13 vertebra level and ipsilateral L3 and L4 rhizotomies, a peripheral NAG (peroneal nerve) was connected to the distal roots stumps, then implanted into the left dorsal column 10 mm rostral to hemicordotomy site (n = 12). After surgery, all animals of the experimental group experienced complete anesthesia in their left hindlimb. Three months later, a slight response to nociceptive stimulation reappeared in L3 and/or L4 dermatomes in 6 of the 12 experimental animals. None of these animals exhibited self-mutilation. Nine months after surgery, we performed retrograde tracing studies by injecting horseradish peroxidase (HRP) into the left dorsal column 30 mm rostral to the NAG implantation site. In eight animals, we found HRP-stained neurons in the left L3 and/or L4 dorsal root ganglia (DRG). The mean number of HRP-stained neurons per DRG was 71 +/- 92 (range 2-259). In control groups, no HRP-stained neurons were found in L3 or L4 DRG. Histological analysis of the NAG showed evidence of axonal regeneration in all 8 animals with positive retrograde labeling of DRG neurons. However, we did not find a statistical correlation between the number of HRP-stained neurons and the degree of sensory recovery. This study demonstrates that an NAG joining dorsal roots to the dorsal column, thus shunting the original CNS-PNS junction, can support regeneration of central axons from DRG primary sensory neurons into the dorsal column over distances of at least 30 mm despite the inhibitory influence of the CNS white matter.Journal of Neuroscience Research 06/2002; 68(3):293-304. · 2.74 Impact Factor
Top co-authors
Top Journals
Institutions
-
2011
-
Cadi Ayyad University
Marrakech, Region de Marrakech-Tensift-Al Haouz, Morocco
-
-
2009
-
Hôpital Bicêtre – Hôpitaux universitaires Paris-Sud
Paris, Ile-de-France, France
-
-
2007
-
Assistance Publique – Hôpitaux de Paris
Paris, Ile-de-France, France
-
-
2004
-
LE CHU DE NIMES : CENTRE HOSPITALIER UNIVERSITAIRE
Nîmes, Languedoc-Roussillon, France
-
