lesión medular

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Sindrome medular

Lesin medular

Fractura de Jefferson Lesiones medularesTrauma

No traumaticasAgudas vascular, hemorragica, tumoral. Subagudascronicas1MEDULA ESPINALDEFINICION: porcin ms caudal del S.N.CEMBRIOLOGIA: porcin caudal del tubo neuralFORMA: cilndrica aplanada en sentido nteroposteriorLONGITUD: 42 45 cm. Columna vertebral: 75 cm.Termina: epicono ( L5 S1) cono terminal filum terminalis DIAMETROS: nteropost. 9-10 mm. lateral : 12 13 mm.ENGROSAMIENTOS: - intumescencia cervical - intumescencia lumbarPESO : 26 27 grs.CURVATURAS : cervical y dorsal

The spinal cord is divided into 31 segments, each with a pair of anterior (motor) and dorsal (sensory) spinal nerve roots. On each side, the anterior and dorsal nerve roots combine to form the spinal nerve as it exits from the vertebral column through the neuroforamina. The spinal cord extends from the base of the skull and terminates near the lower margin of the L1 vertebral body. Thereafter, the spinal canal contains the lumbar, sacral, and coccygeal spinal nerves that comprise the cauda equina. As a result, injuries below L1 are not considered spinal cord injuries (SCIs), because they involve the segmental spinal nerves and/or cauda equina. Spinal injuries proximal to L1, above the termination of the spinal cord, often involve a combination of spinal cord lesions and segmental root or spinal nerve injuries.NeuropathwaysThe spinal cord itself is organized into a series of tracts or neuropathways that carry motor (descending) and sensory (ascending) information. These tracts are organized somatotopically within the spinal cord. The corticospinal tracts are descending motor pathways located anteriorly within the spinal cord. Axons extend from the cerebral cortex in the brain as far as the corresponding segment, where they form synapses with motor neurons in the anterior (ventral) horn. They decussate (cross over) in the medulla before entering the spinal cord.The dorsal columns are ascending sensory tracts that transmit light touch, proprioception, and vibration information to the sensory cortex. They do not decussate until they reach the medulla. The lateral spinothalamic tracts transmit pain and temperature sensation. These tracts usually decussate within 3 segments of their origin as they ascend. The anterior spinothalamic tract transmits light touch. Autonomic function traverses within the anterior interomedial tract. Sympathetic nervous system fibers exit the spinal cord between C7 and L1, whereas parasympathetic system pathways exit between S2 and S4.Injury to the corticospinal tract or dorsal columns, respectively, results in ipsilateral paralysis or loss of sensation of light touch, proprioception, and vibration. Unlike injuries of the other tracts, injury to the lateral spinothalamic tract causes contralateral loss of pain and temperature sensation. Because the anterior spinothalamic tract also transmits light touch information, injury to the dorsal columns may result in complete loss of vibration sensation and proprioception but only partial loss of light touch sensation. Anterior cord injury causes paralysis and incomplete loss of light touch sensation.Autonomic function is transmitted in the anterior interomedial tract. The sympathetic nervous system fibers exit from the spinal cord between C7 and L1. The parasympathetic system nerves exit between S2 and S4. Therefore, progressively higher spinal cord lesions or injury causes increasing degrees of autonomic dysfunction.Vascular supplyThe blood supply of the spinal cord consists of 1 anterior and 2 posterior spinal arteries. The anterior spinal artery supplies the anterior two thirds of the cord. Ischemic injury to this vessel results in dysfunction of the corticospinal, lateral spinothalamic, and autonomic interomedial pathways. Anterior spinal artery syndrome involves paraplegia, loss of pain and temperature sensation, and autonomic dysfunction. The posterior spinal arteries primarily supply the dorsal columns. The anterior and posterior spinal arteries arise from the vertebral arteries in the neck and descend from the base of the skull. Various radicular arteries branch off the thoracic and abdominal aorta to provide collateral flow.The primary watershed area of the spinal cord is the midthoracic region. Vascular injury may cause a cord lesion at a level several segments higher than the level of spinal injury. For example, a lower cervical spine fracture may result in disruption of the vertebral artery that ascends through the affected vertebra. The resulting vascular injury may cause an ischemic high cervical cord injury. At any given level of the spinal cord, the central part is a watershed area. Cervical hyperextension injuries may cause ischemic injury to the central part of the cord, causing a central cord syndrome.

2MEDULA ESPINALLIMITES: - SUPERIOR: a) lnea que pasa por encima del primer par raqudeo b) lnea que pasa por el entrecruzamiento motor c) lnea que pasa por la art. Occpitoatloidea - INFERIOR: lumbar 1-2

MEDIOS DE FIJACION: A- Arriba : bulbo raqudeo B- Abajo: Filum terminalis C- Lateralmente: nervios raqudeos ligamento dentado meninges

Morfologa ExternaCARA VENTRAL : - surco medio anterior - surcos colaterales anteriores

CARA DORSAL - surco medio posterior - surcos colaterales posteriores - surcos intermedios (cervicales) o paramedianos posteriores

Morfologa InternaSustancia Gris tiene forma de H: - astas grises ant. y post. - asta ventral : cabeza y base - asta dorsal : base , cuello cabeza y pex - asta lateral o intermedio lateral ( columna torcica ) - Comisura gris - conducto del epndimo

Sustancia Blanca tres funculos: - ventral, lateral y dorsal

MEDULA ESPINALNERVIOS RAQUIDEOS

Descending tractsAscending tractsTransverse PlaneClasificacin AnatmicaLESIONES EXTRADURALESComprometen el espacio epiduralEjemplos caractersticosHernia discal, osteofitos, metstasis, etc.ImagenologiaDesplazamiento del saco dural y de su contenidoSe puede observar desplazamiento del LLP cuando la masa proviene del disco o cuerpos vertebralesngulos obtusos

Lesion medular: DefinicinEs un insulto a la medula espinal resultando en cambio temporal o permanente de la funcin motora, sensitiva o autonmica. American Spinal Injury Association ASIA. Standards for Neurological Classification of SCI Worksheet. ASIA Store; 2006.Spinal cord injury (SCI) is an insult to the spinal cord resulting in a change, either temporary or permanent, in the cords normal motor, sensory, or autonomic function. Patients with spinal cord injury usually have permanent and often devastating neurologic deficits and disability.9Etiologa10CongnitasDisrafismo espinal:MielomenigoceleEspina bfidaArnoldChiariMalformaciones esquelticasAgenesia lumbosacraAcondroplasiaDesordenes genticosParaplejia espstica hereditariaAdrenomieloneuropatiaLeucodistrofias

Spinal dysraphismSpina bifida occultaMyelomeningocoeleTethered cord syndrome

Adreno-myeloneuropathyOther leukodystrophiesSpinal muscular atrophies11

DeficiencyVitamin B12 deficiencyFolate deficiencyCopper deficiencyRicketsOther deficiencyOsteoporosisPagets diseaseOsteomalacia12Traumaticas

Cord injury:During a typical year, there are about 11,000 spinal cord injuries in the US. Overall, nearly 48% occur in motor vehicle crashes, and 23% result from falls; however, falls are the most common causes in the elderly. The remainder are attributed to assault (14%), sports (9%), and work-related accidents. About 80% of patients are male.

13Mecanismos de lesin

AdquiridosAgudoHoras o diasInfarto o hemorragiaAbsceso

Requiere paraclinicos urgentes para determinar si hay opciones quirurgicas que beneficien al pacienteMas de tres semanasNeoplasiaLesin compresiva cronicaFstula arteriovenosa duralDesorde metablicoProcesos degenerativosAcute onset that worsens within hours or days points to a spinal cord infarct or hemorrhage. When symptoms are recent, it is of paramount importance to rule out a surgical emergency. This requires immediate imaging work-up, ideally total spine magnetic resonance (MR). If there is evidence of spinal cord compression due to an acute lesion (epidural metastasis or abscess), definitive management is required in order to avoid damage or to adequately manage all other potential diagnoses. If the symptoms progress for more than three weeks, transverse myelitis is improbable, and other conditions must be considered, such as a spinal tumor, chronic compressive disease, dural arterio-venous fistula, metabolic disorder, sarcoidosis, or a degenerative process (6).15Estudio de imagenObjetivos del estudio imagenologicoDescartar o confirmar la presencia de lesin medularDeterminar si existe una lesin extrnseca, con afectacin secundaria de la mdula (Mielopata compresiva)16Tcnicas de imagenRadiografa simple: Necesario que se observen todas las vrtebras de forma claraTAC: Reservada para delinear anomalas en estructura sea cuando la radiografa simple es inadecuada RM: Sospecha de lesiones de mdula espinal, ligamentaria y de tejido blando.Imaging techniques in spinal cord injury include the following:Plain radiography - Radiographs are only as good as the first and last vertebrae seen, therefore, radiographs must adequately depict all vertebraeComputed tomography (CT) scanning - Reserved for delineating bony abnormalities or fracture; can be used when plain radiography is inadequate or fails to

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