259 - Tethered Spinal Cord: Fatty Filum Terminale, Meningocele Manqué, and Dermal Sinus Tracts

Abstract

Occult spinal dysraphism (OSD), and in particular dermal sinus tracts, fatty filum terminale, and meningocele manqué, are derived from dorsal midline embryologic maldevelopment. They are often associated with cutaneous stigmata and can lead to neurological deterioration from caudal tethering of the spinal cord. In this chapter, we explore the embryologic underpinnings of spinal cord and filum development, and correlate this development with the interrelationship of OSD with cutaneous stigmata or more complex embryologic malformations. Magnetic resonance imaging (MRI) remains the imaging “gold standard” for all forms of OSD; however, we discuss the variable indications for MRI as opposed to ultrasound. We also examine the pathophysiology of spinal cord tethering and neurological deterioration. Finally, we focus more in-depth on the fatty filum terminale, meningocele manqué, and dermal sinus tract as specific forms of OSD. We explore the incidence and causative etiologies of each (where known), as well as specific associated cutaneous stigmata and presenting symptoms, and discuss relevant diagnostic and surgical treatment pearls in depth.