Herniación medular transdural idiopática: informe de dos casos y revisión de la literatura / Idiopathic transdural spinal cord herniation: report of two cases and literature review

Introducción: La herniación medular transdural idiopática es una entidad rara cuyas formas son la postraumática y posquirúrgica; es omitida en la valoración preoperatoria y con frecuencia afecta al segmento torácico. Clínicamente puede causar mielopatía progresiva o síndrome de Brown-Séquard, cuyo diagnóstico se establece por resonancia magnética. La finalidad de informar esta entidad es su dificultad diagnóstica y, por lo tanto, para establecer un manejo óptimo. Casos clínicos: Dos pacientes mal diagnosticados al inicio e intervenidos en otros segmentos del raquis. Finalmente fueron valorados por sospecha clínica de herniación medular transdural idiopática y por exclusión de otras patologías. Se les realizó laminectomía en los niveles afectados, reducción de la hernia medular y colocación de parche sintético en duramadre. Conclusiones: La herniación medular transdural idiopática se ha atribuido a debilidad congénita de la duramadre o duplicación dural ventral con herniación a través de la capa interna debido a la presión continua del líquido cefalorraquídeo que empuja la médula fuera del espacio subdural. Se estima que el diagnóstico preoperatorio se realiza en una tercera parte de los casos, confirmándose con resonancia magnética. El tratamiento quirúrgico se efectúa en pacientes con progresión de los síntomas; los pacientes cuyos síntomas son leves o ausentes se mantienen bajo monitoreo. El tratamiento oportuno puede permitir la recuperación del déficit neurológico, mejorando la afección motora en 80% y la afección sensitiva en 35%.

BACKGROUND: Idiopathic transdural spinal cord herniation (ISCH) is a rare entity with postsurgical and post-trauma forms. ISCH is often omited in the preoperative evaluation. It often affects the thoracic segment and presents clinically as a rare cause of progressive myelopathy or Brown-Séquard syndrome, whose diagnosis is established by magnetic resonance imaging (MRI). We report on this rare entity due to its difficult diagnosis, making optimal management difficult. CLINICAL CASE: We present the cases of two patients with ISCH who were misdiagnosed and operated on in other spinal segments without reaching an accurate diagnosis. In our institution, patients with clinical suspicion were evaluated by imaging studies in order to rule out other pathologies. Laminectomy was performed on the involved levels, reducing herniation and with the placement of a synthetic spinal patch to the duramater. CONCLUSIONS: ISCH has been attributed to congenital weakness of the duramater or the dural ventral duplication with herniation through the inner layer due to continuous pressure from cerebrospinal fluid that pushes the marrow out of the subdural space. It is estimated that presurgical diagnosis is done only in one third of the cases, confirmed by MRI. Surgery is performed on patients with symptom progression. Surveillance in those patients with mild symptoms is recommended. Treatment may allow recovery of the neurological deficit, improving motor affection in 80% of patients and sensory affection in 35%.

Clinical Features and Treatments of Upper Lumbar Disc Herniations

OBJECTIVE: Disc herniations at the L1-L2 and L2-L3 levels are different from those at lower levels of the lumbar spine with regard to clinical characteristics and surgical outcome. Spinal canals are narrower than those of lower levels, which may compromise multiple spinal nerve roots or conus medullaris. The aim of this study was to evaluate the clinical features and surgical outcomes of upper lumbar disc herniations. METHODS: We retrospectively reviewed the clinical features of 41 patients who had undergone surgery for single disc herniations at the L1-L2 and L2-3 levels from 1998 to 2007. The affected levels were L1-L2 in 14 patients and L2-L3 in 27 patients. Presenting symptoms and signs, patient characteristics, radiologic findings, operative methods, and surgical outcomes were investigated. RESULTS: The mean age of patients with upper lumbar disc was 55.5 years (ranged 31 to 78). The mean follow-up period was 16.6 months. Most patients complained of back and buttock pain (38 patients, 92%), and radiating pain in areas such as the anterior or anterolateral aspect of the thigh (32 patients, 78%). Weakness of lower extremities was observed in 16 patients (39%) and sensory disturbance was presented in 19 patients (46%). Only 6 patients (14%) had undergone previous lumbar disc surgery. Discectomy was performed using three methods : unilateral laminectomy in 27 cases, bilateral laminectomy in 3 cases, and the transdural approach in 11 cases, which were performed through total laminectomy in 10 cases and unilateral laminectomy in 1 case. With regard to surgical outcomes, preoperative symptoms improved significantly in 33 patients (80.5%), partially in 7 patients (17%), and were aggravated in 1 patient (2.5%). CONCLUSION: Clinical features of disc herniations at the L1-L2 and L2-L3 levels were variable, and localized sensory change or pain was rarely demonstrated. In most cases, the discectomy was performed successfully by conventional posterior laminectomy. On the other hand, in large central broad based disc herniation, when the neural elements are severely compromised, the posterior transdural approach could be an alternative.

Intradural Disc Herniation-Transdural Excission.

Intradural disc herniation (IDH) is a rare pathology.Once such case is presented with a discusion on dignosis and management.