Biomedical subjects

M Tadié

Publications and source records attributed to M Tadié.

At least 19 recordsLinked to original sources

PubMed2006

Diaphragm recovery by laryngeal innervation after bilateral phrenicotomy or complete C2 spinal section in rats.

This study aimed to highlight the functional aspects of diaphragm reinnervation by laryngeal motoneurons after bilateral phrenicotomy or complete cervical transection. The left recurrent laryngeal nerve was connected to the left phrenic nerve in 14 rats. Five months later, all bridged rats presented a substantial ipsilateral diaphragm recovery (74.2 +/- 10% of contralateral activity) whereas the diaphragm remained paralysed in non-bridged rats (n = 5/5). After additional right phrenicotomy, functional breathing persisted in bridged rats whereas all non-bridged died. After complete C2 spinal transection, diaphragm respiratory discharges persisted in bridged rats. The reinnnervation by laryngeal motoneurons was confirmed by retrograde labeling, stimulus-elicited diaphragm response by vagal stimulation and diaphragm inactivation after vagotomy. In conclusion, the recurrent-phrenic nerve anastomosis induces a reliable functional diaphragm outcome even after contralateral diaphragm denervation or complete high cervical spinal cord injury, and could be considered as a clinical repair strategy for re-establishing diaphragm autonomy following spinal cord trauma.

Anastomosis, Surgical↗

PubMed2006

A new model of upper cervical spinal contusion inducing a persistent unilateral diaphragmatic deficit in the adult rat.

Research on spinal cord trauma requires models reflecting the contusion mechanisms encountered in clinical situation. The aim of this study was to develop in the adult rat a reproducible model of upper cervical spinal cord contusion inducing persistent unilateral diaphragm deficit. After dura and pia matter removal, weight drop and compression were targeted at the ventro-lateral funiculi which contain the bulbospinal descending respiratory pathways that command the phrenic motoneurons innervating the diaphragm. At 7 days post-injury, the left diaphragm activity recorded in contused rats (27.4 +/- 5.1% of the contralateral activity) was significantly lower than in the sham group (97.6 +/- 1.2%). This respiratory deficit still persisted 1 month later. Histology showed a reproducible left C2-lateralized lesion that involved both white and gray matter including the ventro-lateral funiculi. This C2 contusion model provides a basis for testing both regenerative and neuroprotective strategies aimed at improving functional respiratory recovery after spinal cord trauma.

Animals↗

PubMed2006

Multiple lumbar plexus neurotizations of the ninth, tenth, and eleventh intercostal nerves.

The topographic anatomy of the lower intercostal nerves is less known than the upper ones except for the twelfth intercostal nerve. It is possible to use the lower intercostal nerves to carry out a neurotization of the lumbar roots. We studied the anatomy of the ninth, tenth, and eleventh intercostal nerves in order to specify the data of descriptive and topographic anatomy allowing to carry out their harvesting under good conditions. Ninth, tenth, and eleventh intercostal nerves of 50 cadavers were dissected. The proximal part of the nerve in the posterior intercostal space was exposed through a posterior approach. The lateral intercostal space was exposed through a lateral approach, under the latissimus dorsi, which made it possible to harvest the intercostals nerve. The proximal course of the nerve in posterior intercostals space was the same in all the cases. The nerve moves obliquely towards the outside to reach the lower border of the rib. The exit of posterior intercostal space is a fibrous strait that marks the entry of a channel between two muscular layers. We describe an aponevrotic channel in which the nerve and the vessels are, immediately at the lower border of the cranial rib. The mean total length of intercostal nerve harvested by our technique was 17.96 cm for the ninth intercostal nerve, 17.14 cm for the tenth intercostal nerve, and 15.94 cm for the eleventh intercostal nerve. The bifurcation of the intercostal nerve in a deep branch and the ramus cutaneus lateralis was found in the majority of the cases, from 9.5 to 21 cm of the emergence of the intercostal nerve in posterior intercostal space. This anatomical study of the ninth, tenth, and eleventh intercostal nerves in posterior intercostal space and lateral intercostal space appears to us to allow the realization of a reliable surgical harvesting.

Cadaver↗

PubMed2006

[Endoscope-assisted biopsy for the diagnosis of neurosarcoidosis].

A 56-year-old woman was followed in the neurological department for febrile mental confusion. The diagnosis of sarcoidosis was suggested on the ground of associated abdominal lymphadenopathy, elevated serum angiotensin-converting enzyme level, aseptic meningitis and intracranial hypothalamic lesion. Nevertheless, radiological, biological and histological analyses could not assert the diagnosis of systemic sarcoidosis. Six months later, cerebral MRI showed a recent enhanced nodule, located near the right choroid plexus, inducing a dilatation of the right temporal ventricular horn. A surgical endoscope-assisted biopsy of that lesion was decided. The endoscope was introduced in the right trapped temporal ventricle. The limits between normal and pathological tissues were clearly identified. The biopsy was thus accurately performed. Histological analysis definitely confirmed the diagnosis of neurosarcoidosis. No postoperative complication was noted. We report a case of neurosarcoidosis which was diagnosed by ventricular endoscope-assisted biopsy. The discussion stresses the potential advantages of endoscopy for the diagnosis of small periventricular lesions when ventricular dilatation is associated.

Biopsy↗

PubMed2006

MR diffusion tensor imaging and fiber tracking in 5 spinal cord astrocytomas.

Spinal cord astrocytomas are rare neoplasms that can result in alteration of the spinal cord structural integrity, which can be assessed by using diffusion tensor imaging methods. Our objective was to visualize the deformation of the posterior spinal cord lemniscal and corticospinal tracts in 5 patients with low-grade astrocytomas compared with 10 healthy volunteers by using 3D fiber-tracking reconstructions.

Adult↗

PubMed2005

[Temporary vessel occlusion].

UNLABELLED: In many situations, temporary artery occlusion is an integral component of aneurysm surgery. The use of temporary clip may allow safer and easier aneurysmal dissection and clipping. Several points, concerning the duration and overall risks of temporary occlusion and the method of choice for cerebral function monitoring have to be discussed. MATERIAL AND METHODS: Non exhaustive review of neurosurgical literature. DISCUSSION: Temporary clip application decreases the risk of intraoperative aneurysmal rupture. The analysis of data published in the literature showed that several questions remain open concerning the optimal method of neuroprotection and cerebral function monitoring, as well as the limit of occlusion duration. Other clinical trials are needed to assess the efficacy and safety of this technique.

Brain Ischemia↗

PubMed2005

Cross-neurotization of the caudal brachial plexus with the contralateral C-8 ventral nerve branch in the cat. Potential surgical applications, effects of graft collection on the healthy donor limb and results.

Contralateral transfer of the right, eighth ventral nerve branch (C8) (C8 cross-transfer - C8CT) was performed in 6 adult cats, in which the caudal part of the left brachial plexus (C8 and T1) had been severed, in order to mimic nerve root avulsion. Clinical and electrophysiological parameters, muscle contraction force measurements and histology were used to evaluate the effects of the surgery in a 14- to 36-month follow-up. The right forelimb (donor side) was clinically normal (no lameness) in all the cats at the end of the study. Electromyography performed 14 days after surgery revealed denervation fibrillation potentials in both forelimbs. Fibrillation potentials disappeared in all the cats at the end of the study. Direct stimulation of the right C8 ventral branch induced motor and sensory evoked potentials in the left limb muscles in all the cats. The left to right contraction ratio of the extensor carpi radialis muscle was approximately 1. This experimental study demonstrates that C8CT enables re-innervation of the contralateral brachial plexus and allows the establishment of new functional neuromuscular units. This can in turn enable the restoration of function, and could potentially lead to partial recovery after caudal brachial plexus avulsion in the cat.

Action Potentials↗

PubMed2005

[Endoscope-assisted microsurgery for invasive endo- and suprasellar pituitary macroadenomas: a consecutive retrospective study with 13 patients].

BACKGROUND AND PURPOSE: Surgery of invasive endo- and suprasellar pituitary macroadenomas remains difficult. The records of 13 consecutive patients who underwent transsphenoidal surgery were analyzed in order to evaluate advantages and limitations of endoscopy for surgery of invasive pituitary macroadenomas. METHODS: A transseptal transsphenoidal intersepto-columellar approach was performed with a nasal 0-degree endoscope. Removal of the macroadenoma was performed under the control of a microscope. When the tumor seemed to be completely removed with microscope, a rigid 30-degree endoscope was inserted in the intrasellar and suprasellar regions in order to detect residual adenoma tissue. These residues were removed when technically possible. RESULTS: No rhinologic complication was noted. In 7 patients, the intra- and suprasellar endoscopic view detected a tumor residue which could be removed in each case. Two cases of cerebrospinal fluid leakage occurred during the complementary tumor resection. Two cases of diabetes insipidus and two of rhinorrhea were reported postoperatively. The analysis of the postoperative MRIs showed a complete removal in 23% of the patients (3/13), 75 to 100% removal in 54% of the patients (7/13), 50 to 75% removal in 8% of the patients (1/13) and 50% removal in 15% of the patients (2/13). More than 75% removal was thus achieved in 77% of the patients (10/13). The mean follow-up was 27.2 months. CONCLUSIONS: Rhinologic morbidity was reduced with the endoscopic endonasal approach. Endoscopy complemented with a microscope offered an optimal view of the intra- and suprasellar regions. Endoscopy also improved tumor resection of the invasive endo- and suprasellar pituitary macroadenomas by visualizing hidden suprasellar tumor residues. However, endoscopy was associated with a higher rate of postoperative rhinorrhea.

Adenoma↗

PubMed2004

The thoracoabdominal intercostal nerves: an anatomical study for their use in neurotization.

The topographic anatomy of the lower intercostal nerves is less known than that of the upper ones, except for the subcostal nerve (twelfth intercostal nerve). It is possible to use the lower intercostal nerves to neurotize the lumbar roots. We studied the anatomy of the ninth, tenth and eleventh intercostal nerves in order to specify the descriptive and topographical anatomical data that will allow their harvest in good condition. The ninth, tenth and eleventh intercostal nerves of 30 cadavers were dissected. The proximal part of the nerves in the posterior intercostal space was exposed through a posterior approach. The lateral intercostal space was exposed through a lateral approach, deep to the latissimus dorsi, that made it possible to harvest the intercostal nerve. The proximal course of the nerves in the posterior intercostal space was the same in all cases. The nerves move obliquely towards the outside to reach the lower border of the rib. The exit of the posterior intercostal space is a fibrous strait, which marks the entry of a channel between two muscular layers. We describe an aponeurotic channel in which the nerve and vessels run, immediately at the lower border of the cranial rib. The mean total length of intercostal nerve harvested by our technique was 17.86 cm for the ninth intercostal nerve, 16.95 cm for the tenth and 15.75 cm for the eleventh. Bifurcation of the intercostal nerve into a deep branch and the lateral cutaneous branch was found in the majority of the cases, 9.5-21 cm from the emergence of the intercostal nerve in the posterior intercostal space. This anatomical study of the ninth, tenth and eleventh intercostal nerves in the posterior intercostal and lateral intercostal spaces appears to us to allow reliable surgical harvesting.

Cadaver↗

PubMed2004

Experimental bypass surgery between the spinal cord and caudal nerve roots for spinal cord injuries.

Spinal cord injuries often cause permanent neurological deficits and are still considered as inaccessible to efficient therapy. Injured spinal cord axons are unable to spontaneously regenerate in adult mammalians. Re-establishing functional activity especially in the lower limbs by reinnervating the caudal infra-lesional territories could represent an attractive therapeutic strategy. For several years, we have studied and developed surgical bypasses using peripheral nerve grafts bridging the supra-lesional rostral spinal cord to the caudal infra-lesional lumbar roots. Main objectives were: 1- to overcome the spinal cord lesion and the consecutive glial barrier blocking the axonal regeneration; 2- to find and bring an alternative source of regenerating axons; 3- to guide those axons toward precisely definite targets (for example, lower limb muscles). We report here the results of our experimental research, which led us from animal experimental models (rodents, primates) to the first human experimentation. Limitations of the method (especially technical pitfalls) are numerous. However, we have obtained encouraging results in our attempts to "repair" the motor pathway. Functional recovery with strong evidence of centrifugal axonal regeneration from the spinal cord to the periphery has been observed. Regarding the sensory pathway, we have found evidence of centripetal axonal regeneration from the periphery toward the spinal cord. Further studies are obviously advocated, but our experimental model of spinal cord - nerve roots bypasses may be integrated in future "repair" strategies of both motor and sensory pathways following spinal cord injury.

Animals↗

PubMed2004

Late spinal dislocation after treatment of spinal arteriovenous malformation. A case of Charcot spinal arthropathy.

Neuropathic arthropathy of the spine is a destructive condition of the spine which is secondary to a loss of the protective proprioceptive reflexes. In the majority of cases, it occurs in patients who have suffered from traumatic medullary lesions and is responsible for destruction of the vertebral bodies and considerable spinal deformity. We report a case of neurogenic lumbar arthropathy in a patient with a spinal arteriovenous malformation. This vascular lesion caused considerable disturbances of proprioception. The course was favorable with regard to the deformity after correction and fusion by posterior approach.

Adult↗

PubMed2004

Effects of surgery on the sensory deficits of syringomyelia and predictors of outcome: a long term prospective study.

OBJECTIVE: To quantify the effects of surgery on the thermal deficits of syringomyelia and assess the predictors for such effects. METHODS: The subjects were 16 consecutive patients (12 men, 4 women; mean (SD) duration of sensory symptoms, 5.1 (4.5) years) presenting with the typical symptoms of syringomyelia related to Chiari I malformation or trauma, and requiring surgical treatment. They were evaluated before surgery, then at six months and two years. Sensory evaluation included determination of the extent of thermal deficits and quantitative assessment of thermal, mechanical, vibration detection, and pain thresholds. Neuropathic pain intensity was evaluated on visual analogue scales. Magnetic resonance imaging was done before and after surgery to measure syrinx dimensions. RESULTS: The magnitude and extent of thermal deficits improved in a subgroup of patients and this was best predicted by the duration of sensory symptoms: patients operated on less than two years after the onset of their symptoms tended to improve, while those operated on later were stabilised or deteriorated slightly. The effect of surgery on thermal deficits was correlated with the duration of sensory symptoms. Surgery also affected vibration deficits in patients with the Chiari malformation, neuropathic pain on effort, and syrinx dimensions. CONCLUSIONS: The duration of sensory deficits is the best predictive factor of the efficacy of surgery for the thermal symptoms of syringomyelia. Early surgery is required if these deficits are to be minimised.

Adult↗

PubMed2004

Neuroprotective effect of gacyclidine. A multicenter double-blind pilot trial in patients with acute traumatic brain injury.

The aim of this study was to assess the safety and efficacy of intravenous (IV) injections of gacyclidine, a novel NMDA receptor antagonist, for neurological and functional recovery following acute traumatic brain injury. This multicenter, prospective, randomized, placebo-controlled, double-blind study compared four parallel groups. Two IV doses were administrated (placebo, 2x0.005mg/kg, 2x0.001mg/kg, 2x0.02mg/kg): the first dose was given within 2 hours following the trauma, and the second dose 4 hours after the first. Fifty-one patients were enrolled and 48 studied between March 1995 and June 1997 in France. Evaluation criteria for safety were physical examination, cardiovascular parameters, blood chemistry, hematology, ECG, and neuropsychological changes monitored after medication. Primary evaluation criteria for efficacy was the Glasgow coma scale complemented by the initial CT-scan and Glasgow outcome scale, motor deficiencies, neuropsychological changes, and functional indenpendence at D90 and D365 or endpoint. Intracranial pressure (ICP) monitoring was not taken into account because all the clinical centers participating in this study did not use this technique in daily practice during the inclusion period. Twelve patients died during the follow-up period, none of these deaths being related to the drug. Serious adverse events (181) were reported by most of the patients with no significant differences between groups. Only 10 of these adverse events were considered to be drug-related. Safety-related laboratory tests did not show any relevant changes. Concerning efficacy, the predefined prognostic factors (initial CT-scan score, initial Glasgow Coma Scale and occurrence of low systolic blood pressure during the first 24 hours) largely determinated the patient's outcome. When the prognostic factors were taken into account together with the dose level in a logistic regression model, gacyclidine showed a beneficial long-term effect and a best dose-result in the 0.04mg/kg treated group. Data obtained in this clinical trial appeared sufficient to warrant a European multicenter study on gacyclidine using the same evaluation criteria and ICP monitoring.

Adolescent↗

PubMed2001

Comparison of dopamine and norepinephrine after traumatic brain injury and hypoxic-hypotensive insult.

After severe brain trauma, blood-brain barrier disruption and alteration of cerebral arteriolar vasoreactive properties may modify the cerebral response to catecholamines. Therefore, the goal of the present study was to compare the effects of dopamine and norepinephrine in a model of brain injury that consisted of a weight-drop model of injury complicated by a 15-min hypoxic-hypotensive insult (HH). Sprague-Dawley rats (n = 7 in each group) received, after brain injury, an infusion of either norepinephrine (TNE group) or dopamine (TDA group) in order to increase cerebral perfusion pressure (CPP) above 70 mm Hg. In addition, a control group (C group, no trauma) and a trauma group (T group, brain injury, no catecholamine infusion) were studied. Mean arterial pressure (MAP), intracranial pressure (ICP, intraparenchymal fiberoptic device), and local cerebral blood flow (LCBF, extradural laser-Doppler fiber) were measured throughout the protocol. In T group, brain injury and HH induced a decrease in CPP (by an increase of ICP and a decrease of MAP), and a decrease of LCBF. Both norepinephrine and dopamine failed to increase CPP, and ICP was significantly higher in TNE and TDA groups than in T group. Interestingly, norepinephrine was not able to alleviate the decrease in MAP. Neither norepinephrine or dopamine could induce an increase of MAP. LCBF decreased similarly in T, TNE and TDA groups. In conclusion, norepinephrine and dopamine are not able to restore values of CPP above 70 mm Hg in a model of severe brain trauma. Furthermore, their systemic vasopressor properties are altered.

Animals↗

PubMed2001

[Spontaneous regression of paraplegia caused by spontaneous cervico-thoracic epidural hematoma].

Spontaneous spinal epidural hematoma is a rare condition that usually requires surgical treatment in emergency. We report the unusual and well-documented case of a spontaneous spinal epidural hematoma, extending from C6 to T2, occurring in a 56-year old man and causing paraplegia. Without surgery, the paraplegia spontaneously and completely recovered within the first 24 hours. Serial MRI studies demonstrated the remitting course of the spinal epidural hematoma. Emergency surgical evacuation should still be the standard treatment for patients with disabling and/or persistent neurologic deficit. A conservative approach under close neurologic observation may be recommended for patients with no or mild deficits, for patients who show early and continuous clinical improvement within the first 24 hours and for patients with small and/or non-compressive spinal epidural hematoma. Reported cases of spontaneous remission are very rare.

Cervical Vertebrae↗

PubMed2001

[Imaging of syringomyelia].

This review reports the value of current imaging techniques in the diagnosis of syringomyelia excluding tumoral causes. The value of imaging techniques for evaluation of extension, detection of associated anomalies, and pre- and postoperative evaluation are detailed.

Humans↗

PubMed2000

Motoneurons of the adult marmoset can grow axons and reform motor endplates through a peripheral nerve bridge joining the locally injured cervical spinal cord to the denervated biceps brachii muscle.

Reconnection of the injured spinal cord (SC) of the marmoset with the denervated biceps brachii muscle (BB) was obtained by using a peripheral nerve (PN) bridge. In 13 adult males, a 45 mm segment of the peroneal nerve was removed: one end was implanted unilaterally into the cervical SC of the same animal (autograft), determining a local injury, although the other end was either directly inserted into the BB (Group A) or, alternatively, sutured to its transected motor nerve, the musculocutaneous nerve (Group B). From 2-4 months post-surgery, eight out of the 10 surviving animals responded by a contraction of the BB to electrical stimulations of the PN bridge. All ten were then processed for a morphological study. As documented by retrograde axonal tracing studies using horse radish peroxidase or Fast Blue (FB), a mean number of 314 (Group A) or 45 (Group B) spinal neurons, mainly located close to the site of injury and grafting, re-expressed a capacity to grow and extend axons into the PN bridge. Most of these regenerated axons were able to grow up to the BB and form or reform functional motor endplates. Many of the spinal neurons that were retrogradely labeled with FB simultaneously displayed immunoreactivity for choline acetyl-transferase and consequently were assumed to be motoneurons. Reinnervation and regeneration of the BB were documented by methods revealing axon terminals, endplates and myofibrillary ATPase activity. Our results indicate that motoneurons of the focally injured SC of a small-sized primate can, following the example of the adult rat, re-establish a lost motor function by extending new axons all the way through a PN bridge connected to a denervated skeletal muscle.

Animals↗

PubMed2000

[Horseradish peroxidase retrograde labeling of primary sensory axons in rats: a comparison between three different intraspinal injections methods].

STUDY AIM: In order to improve the results of intraspinal retrograde labeling of post-ganglionic primary sensory axons by horseradish peroxidase (HRP), the authors compared three different intraspinal injection methods of this tracer into the inferior thoracic spinal cord in the rat. MATERIAL AND METHOD: 'Open field' method (group 1, N = 8); stereotactic injection, needle tip diameter = 0.72 mm (group 2, N = 8); stereotactic injection, needle tip diameter = 0.24 mm (group 3, N = 8). Histological features of the spinal injection site showed that tissue damages due to injection was more extensive and deeper than expected. HRP transported in retrograde fashion from injection site to sensory body cells located in dorsal root ganglia (DRG) was revealed by the Mesulam histochemical technique. RESULTS: The mean number of labeled neurons per DRG was 652 in group 3, 116 in group 2, and 77 in group 1. Differences were statistically significant, especially between groups 1 and 3 (P = 4.10(-16)) and groups 2 and 3 (P = 2.10(-17)). CONCLUSION: Retrograde labeling of primary sensory axons by HRP (or another axonal tracer) with fine needle stereotactic intraspinal injection may represent an alternative to anterograde labeling. This reliable and reproducible method may be useful in studies dealing with regeneration of post-ganglionic primary sensory axons.

Animals↗