Clinical Presentation. To describe the diagnosis and treatment options for LSS, description of the clinical presentation is warranted. LSS is defined by any type of narrowing of the spinal canal, nerve root canals, or intervertebral foramina [].LSS can be classified based on the cause of the stenosis, (i.e., congenital or acquired) or based on the anatomic location (i.e., central, foraminal ....