Editing Neurogenic LUT Dysfunction (section)

=== Disk disease ===
* '''Spinal Cord Anatomy'''
** '''In the adult, the sacral spinal cord begins at spinal column (vertebral bodies) levels T12 to L1 and terminates in the cauda equina at spinal column level L2'''
*** In this distal end of the spinal cord (conus medullaris), the spinal cord segments are named for the vertebral body at which the nerve roots exit the spinal canal.
*** Thus, although the sacral spinal cord segment is located at vertebral segment L1, its nerve roots run in the subarachnoid space posterior to the L2 to L5 vertebral bodies until reaching the S1 vertebral body, at which point they exit the canal.
*** Therefore, '''all of the sacral nerves that originate at the L1 and L2 spinal column levels run posterior to the lumbar vertebral bodies until they reach their appropriate site of exit from the spinal canal.''' '''This group of nerve roots running at the distal end of the spinal cord is commonly referred to as the cauda equina.'''
*** Conus medullaris vs. cauda equina
**** The most distal bulbous part of the spinal cord is called the '''conus medullaris''', and its tapering end continues as the filum terminale. Distal to this end of the spinal cord is a collection of nerve roots, which are horsetail-like in appearance and hence called the '''cauda equina''' (Latin for horse's tail)§
* '''Usually, disk prolapse is in a posterolateral direction, which does not affect the majority of the cauda equina. However, in 15% of cases, central disk prolapse occurs and compression of the cauda equina may result.'''
** '''Thus, disk prolapse anywhere in the lumbar spine could interfere with the parasympathetic and somatic innervation of the LUT, striated sphincter, and other pelvic floor musculature, and afferent activity from the bladder and affected somatic segments to the spinal cord.'''
** '''Most disk protrusions compress the spinal roots in the L4 to L5 or L5 to S1 vertebral interspaces.'''
*** '''DESD does not occur as the injury is infrasacral'''
* '''When LUT dysfunction is present, it typically occurs with the usual clinical manifestations of low back pain radiating in a girdle-like fashion along the involved spinal root areas. The most characteristic findings on physical examination are sensory loss in the perineum or perianal area (S2 to S4 dermatomes), sensory loss on the lateral foot (S1 to S2 dermatomes), or both.'''
* '''Detrusor areflexia occurs in 27% of patients with lumbar disk disease'''
* '''The most consistent urodynamic findings are:'''
** '''Normal compliance'''
** '''Areflexic bladder associated with normal innervation or findings of incomplete denervation of the perineal floor musculature.'''
** Occasionally, patients may show detrusor overactivity, attributed to irritation of the nerve roots
* '''Laminectomy may not improve LUT function in many cases''', and prelaminectomy urodynamic evaluation is prudent because it may be difficult postoperatively to separate causation of voiding dysfunction resulting from the disk sequelae from changes secondary to the surgery.
* Cauda equina syndrome is a term applied to the clinical picture of perineal sensory loss with loss of voluntary control of both anal and urethral sphincter and of sexual responsiveness. Patients undergoing surgery are found to have an acontractile bladder and no bladder sensation. This can occur not only secondary to disk disease (severe central posterior disk protrusion) but also to other pathologic processes affecting the spinal canal.