Intraspinal extradural variations of nerve roots

Abstract

Introduction: The aim of this work is to point out the intraspinal extradural anatomical variations of nerve roots and their possible participation in radiculopathy.

Methods: The anatomical study was performed in 33 cadavers at a mean age of 46.5 and up to 24h from death. All extradural anastomoses between nerve roots were excised and examined histologically for the presence or absence of nervous tissue. The type of the plexus was defined by subtracting from the root C2.

Results: Findings with the normotype of plexus formation prevailed in 24 cases (72.7%). Variations in its formation were observed in 9 cases (27.3%). The prefixed type in 6 cases (18.2%), post-fixed type in 3 cases (9.1%). We did not observe the formation of the isolated prefixed or post-fixed types in the brachial or lumbosacral plexuses. Extradural anatomical variations occurred in 20 cases (60.6%). They were more frequent on the left, in 10 cases (30.3%), bilateral in 3 cases (9.1%). In 8 instances (24.2%), the atypical spacing, including four in the lumbosacral region, was observed. Variations occurred more frequently in variations of formation of the plexus.

Conclusions: This study allowed us to identify and describe unpublished intraspinal extradural anatomical variations of nerve roots and their interrelationships throughout the spinal canal with their potential influence on the clinical picture. Anatomical preparations revealed a higher incidence of intraspinal extradural variations, mainly between sacral roots. The reliance of their incidence of the type of plexus was observed.

Keywords: Extradural nerve roots; Intraspinal nerves; Nerve roots variations.