Cauda equina biopsy as a tool in the diagnosis of malignant tumors

The prevalence of malignant lymphoma is increasing. With the advent of novel therapeutic approaches, the distinct pathology of each type of malignant lymphoma is used to tailor its treatment for the most effective outcome. Therefore, analysis of the malignant cell pathophysiology within the cauda equina is important to devising a treatment strategy. In some cases, the tumor only invades the cauda equina. Composed of an uninterrupted bundle of nerve fibers, the cauda equina is more complex than the brain parenchyma; hence, the method for performing a biopsy of the cauda equina is relatively more challenging and requires improvement. The appropriate surgical procedure to confirm the posterior ramus, which consists of sensory roots, is mandatory. In the lumbar region, the denticulate ligaments that distinguish between the motor and sensory nerve roots do not exist. Microsurgical techniques and neurophysiological monitoring can aid with removal of posterior roots and allow for the reliable performance of a cauda equina biopsy. First, we determined where the spinal root pierces the dura mater, and then we performed electromyography. We performed cauda equina biopsy with this method for patients with malignant lymphoma and reviewed the efficacy of this procedure. This strategy prevented postoperative neurological impairments and provided detailed information to ensure optimal adjuvant therapy. Based on advances in personalized therapies for malignant tumors, opportunities for cauda equina biopsy are increasing. Our method using both morphological feature observation and neurophysiological monitoring may contribute to successful biopsy of the cauda equina.