Journal List > J Korean Soc Spine Surg > v.20(4) > 1076006

Kim and Lee: Anatomical and Pathophysiological Features of Cauda Equina

Abstract

Study Design

Review of literature on anatomical and pathophysiological features of cauda equina.

Objectives

To look into the anatomical and pathophysiological features of cauda equina and support their basic knowledge of treating cauda equina syndrome.

Summary of Literature Review

Cauda equina has different anatomical and pathophysiological features to peripheral nerve.

Materials and Methods

Review of literature.

Results

When compressing to cauda equina, the pathophysiologic mechanism develop as follows; increasing the vascular permiablity of nerve root, intraneural edema, and subsequent blood and nutritional impairment. Nerve root injury develops through this pathophysiologic mechanism.

Conclusions

Cauda equina has an extensive ateriovenous anastomosis and guaze-like pia mater, which supply blood and neutrition to it. These anatomical features prevent it from complete cauda equina syndrome when compressing to it under arterial blood pressure.

REFERENCES

1. Konno S, Olmarker K, Byrod G, Rydevik B, Kikuchi S. Intermittent cauda equina compression: an experimental study of the porcine cauda equina with analyses of nerve impulse conduction properties. Spine (Phila Pa 1976). 1995; 20:1223–6.
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2. Konno S, Yabuki S, Sato K, Olmarker K, Kikuchi S. A model for acute, chronic and delayed graded compression of the dog cauda equina. Presentation of the gross, microscopic and vascular anatomy of the dog cauda equina and accuracy in pressure transmission of the compression model. Spine (Phila Pa 1976). 1996; 20:2758–64.
3. Olmarker K, Rydevik B. Single versus double level nerve root compression: an experimental study on the porcine cauda equina with analyses of nerve impulse conduction properties. Clin Orthop. 1992; 279:35–9.
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Fig. 1.
Intradural arrangement of cauda equina. The most caudal roots (black arrow) is located in central and posterior position, and the most cephalad roots (asterix) is located in lateral and anterior position. In addition, motor fiber is located in medial and anterior to sensory fiber (Photography by Shinich Kikuchi, MD, PhD).
jkss-20-210f1.tif
Fig. 2.
Photo showing the differences between spinal nerve root (asterix) and cauda equine (black arrows). Cauda equina has no connective tissue, adipose tissue, perineurium, epineurium, and endonurium (VR: ventral root, DR: dorsal root, DRG: dorsal root ganglion, Photography by Shinich Kikuchi, MD, PhD).
jkss-20-210f2.tif
Fig. 3.
Inter- and intrafascicular arteries showing compensating coils to allow interfascicular movement (1:Radicular artery, 2: interfascicular artery, 3: intrafascicular artery). Cited from Parke WW, Watanabe R, Spine (Phila Pa 1976). 1985;10:508-15.
jkss-20-210f3.tif
Fig. 4.
Graphic complilation showing the structure of a typical lumbosacral nerve root derived from data obtained by injection studies. 1. Fas-cicular pia; 2. Inter- and intrafascicular arteries 3. Longitudinal radicular artery; 4. Large radicular vein; 5. Arteriovenous anastomosis; 6. Collateral radicular artery; 7. Gauzelike pia-arachnoid that permits percolation of CSF to assist in metabolic support. Cited from The Spine Fifth Ed. Page 49 Figure 2-42.
jkss-20-210f4.tif
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