Lumbar neurinomas: their unknown causes and treatment
Written by:Neurinomas are generally benign tumors that can arise at both the cranial and spinal levels. When located at the lumbar level, they can compress the roots of the cauda equina or the medullary cone, which is the terminal part of the spinal cord. To speak to us in detail of this pathology is Dr. Nicola Montano, an expert in Neurosurgery in Rome
What are Neurinomas and where do they localize?
Neurinomas, or schwannomas, are tumors that originate from glial cells belonging to the peripheral nervous system, Schwann cells. The main function of these cells, by coating the axons of neurons with a layer of myelin, is to increase the speed of nerve impulse conduction. Neurinomas typically originate in the transition zone from central myelin to peripheral myelin. Usually they are single tumors, with a maximum incidence around 50-60 years. In the case in which they develop in multiple forms, one could be faced with a genetic syndrome called neurofibromatosis. Neuromas are generally benign neoplasms, with a very slow growth rate and, therefore, at the time of diagnosis, they may already have reached considerable size.
Neurinomas can be located at the cranial level, at the spinal level and along the course of any peripheral nerve. At the spinal level, the most frequent sites are the cervical spine and the lumbar spine. At the lumbar level, extra-medullary intradural tumors are usually generated from one of the nerve roots of the cauda equina and compress the other roots or the terminal portion of the spinal cord, the medullary cone. When the tumor is very small, magnetic resonance may be visible as an appendage of the nerve itself. During growth it can compress and cause distortion of the surrounding nerve roots, eventually becoming close to them. Neurinomas can also be localized extradurale, leading to an enlargement of the spinal conjugation foramen.
What are the causes and symptoms at the lumbar level?
During the initial stages, the symptoms are generally characterized by root pain and paresthesia (tingling and / or falling asleep). Pain located at the lumbar level may be an early symptom of this condition and should therefore not be underestimated. When the tumor increases in size and compresses the neighboring nerve roots, other symptoms appear that take the name of cauda equina syndrome. This syndrome is characterized by the presence of: low back pain, lower limb pain, weakness in the lower limbs, difficulty in walking, urinary dysfunction, defecation changes, hypo-anesthesia in the perineal and perianal region (saddle-type anesthesia) "). Neurinomas generally develop in healthy patients due to unknown causes. As mentioned previously, especially if multiple, they can be part of a genetic syndrome called Neurofibromatosis.
Lumbar Neurinomas: diagnosis and treatment
First of all, the diagnosis can be based on a careful evaluation of the patient's symptoms. From the radiological point of view the examination of choice is the magnetic resonance with contrast medium. In general, neurinomas appear as oval lesions often associated with bone remodeling of the conjugation foramen that can be spread due to the presence of the tumor. Frequently they can present hemorrhagic areas in the context and cystic degeneration. Virtually there is always a strengthening of the lesion after administration of the contrast agent.
The therapy of choice is surgery. Its purpose is to remove the tumor, if possible completely, to provide for decompression of the nerve structures and to stabilize the vertebral column if necessary. The intraoperative neurophysiological monitoring and the use of the operating microscope are fundamental and have allowed to improve the neurological prognosis of these lesions. From this point of view, the most important predictive factor remains the pre-operative neurological state because a good pre-operative neurological function is associated with a better functional prognosis (Montano et al. Furthermore, the use of laminoplasty as a technique of approach to these tumors greatly reduces the incidence of post-operative complications such as the fluvial fistula, the appearance of deformity and the need to perform stabilization at a distance of the spine (Montano et al., 2014 ).