Intraspinal intradural variations of nerve roots.

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

METHODS: The anatomical study was performed in 33 cadavers. There were 25 male cadavers aged 30-75 years and 8 female cadavers aged 45-77 years, with a mean age of 46.5 years to 24 h from death. All intradural rami communicantes 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 of the normotype of plexus formation occurred in 24 cases (72.7%). Variations in its formation were observed in nine cases (27.3%). The prefixed type was observed in six cases (18.2%), postfixed type in three cases (9.1%). The formation of isolated prefixed or postfixed type of the brachial and lumbosacral plexus was not observed. Anatomical preparations revealed intradural variations in all cases of the lumbosacral plexus, 22 times (66.7%) in cases of cervical roots, and in the thoracic region seven times (21.2%). Variations occurred more frequently in variations of plexus formation.

CONCLUSIONS: This study allowed us to identify and describe unpublished intraspinal intradural anatomical variations of nerve roots, and their interrelationships throughout the spinal canal with their potential influence on the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 intradural variations, particularly between sacral roots. Reliance of their incidence of the plexus type was observed.