REGIONAL CORRESPONDENCE BETWEEN THE VENTRAL PORTION OF THE LUMBAR INTERVERTEBRAL DISC AND THE GROIN MEDIATED BY A SPINAL REFLEX - A POSSIBLE BASIS OF DISCOGENIC REFERRED PAIN
Y. Takahashi et al., REGIONAL CORRESPONDENCE BETWEEN THE VENTRAL PORTION OF THE LUMBAR INTERVERTEBRAL DISC AND THE GROIN MEDIATED BY A SPINAL REFLEX - A POSSIBLE BASIS OF DISCOGENIC REFERRED PAIN, Spine (Philadelphia, Pa. 1976), 23(17), 1998, pp. 1853-1858
Study Design. Lumbar peripheral nerves were examined to determine whet
her they were responsive to electrical stimulation of the ventral port
ion of the lumbar disc in anesthetized rats, Objectives. To confirm by
electrophysiologic means the neural correspondence between the ventra
l portion of the lumbar disc and the groin. Summary of Background Data
. Patients with a degenerated lumbar disc occasionally report groin pa
in. However, its pathogenesis has not been investigated. The authors o
f the current study found that chemical stimulation of the ventral por
tion of rat lumbar disc caused cutaneous plasma extravasation in the g
roin, and thereby hypothesize the neural relation between the lumbar d
isc and the groin. Methods. The ventral portion of rat L5-L6 disc was
electrically stimulated, and the elicited action potentials were recor
ded from the iliohypogastric, genitofemoral, lateral femoral cutaneous
, sural, and sciatic nerves. The roles of the lumbar sympathetic trunk
s and spinal cord in the generation of the action potentials were exam
ined. Results. Action potentials were elicited principally in the geni
tofemoral nerve; the action potentials of the genitofemoral nerve were
not influenced by transection of the cervical spinal cord, whereas th
ey disappeared immediately after death, which indicates that they are
induced by a spinal reflex. The action potentials were reduced conside
rably after destruction of the lumber sympathetic trunks, suggesting t
hat they comprise an afferent path of the reflex. Conclusions. The ven
tral portion of the lumbar disc had spatial relation to the groin area
via a spinal reflex. Such a relation suggests that a disorder in the
ventral portion of the lumbar disc may be a possible source of groin r
eferred pain.