A rapid transport route between the epidural space and the intraneural capillaries of the nerve roots.
METHODS
The possibility of epidurally applied substances reaching the intraneural capillaries of the spinal nerve roots and cauda equina was assessed in the pig sacrococcygeal spine.


METHODS
The presence of Evans blue-labelled albumin in intraneural capillaries after epidural application for 1, 10, or 30 minutes was studied with fluorescence microscopy. Ink angiography was used to determine whether there were any direct communicating vessels between the epidural vein plexus and the intraneural capillaries.


RESULTS
Evans blue-labelled albumin was present in the intraneural capillaries 1 minute after epidural application. Microangiography demonstrated small venules that connected the epidural vein plexus and the intraneural capillaries.


CONCLUSIONS
The results of this study demonstrated a rapid transport route between the epidural space and the intraneural capillaries. The results suggest that nucleus pulposus material, as well as epidurally applied substances, such as local anesthetic drugs or epidurally injected corticosteroids, may have a rapid, direct transport route to the axons of the spinal nerve roots. The demonstrated transport route also may be related to the mechanisms behind epidural anesthesia and spinal nerve root infiltration.
Byröd
G
G
Department of Orthopaedics, Sahlgren Hospital, Gothenburg University, Sweden.
Olmarker
K
K
Konno
S
S
Larsson
K
K
Takahashi
K
K
Rydevik
B
B
D000418:Albumins / Q000493:pharmacokinetics*; D000818:Animals; D001775:Blood Circulation; D002196:Capillaries / Q000502:physiology; D002420:Cauda Equina / Q000098:blood supply; D004824:Epidural Space / Q000098:blood supply*; D005070:Evans Blue / Q000493:pharmacokinetics; D005451:Fluorescein Angiography; D007796:Laminectomy; D008856:Microscopy, Fluorescence; D013126:Spinal Nerve Roots / Q000098:blood supply*; D013552:Swine
D000418:Albumins; D005070:Evans Blue