Extraordinary features of the intraspinal extradural and intradural nerve root courses.

OBJECTIVES: Very few studies have reported occasional intradural and extradural communications between adjacent nerve roots. These studies mostly focus on lumbosacral regions followed by cervical regions, and rarely in the thoracic region. DESIGN: The aim of this work is to point out some extraordinary extradural and intradural features of the intraspinal nerve root courses and their possible participation in radiculopathy. SUBJECTS AND METHODS: The anatomical study was performed in 43 cadavers. All intradural and extradural rami communicantes between nerve roots were examined histologically for the presence or absence of nervous tissue. RESULTS: Findings of the normotype of plexus formation occurred in 30 cases (69.8%). Variations in its formation were observed in 13 cases (30.2%). Anatomical preparations revealed intradural rami communicantes in all cases of the lumbosacral plexus; 28 times (65.1%) in cases of cervical roots and in the thoracic region 4 times (9.3%). Extradural anatomical variations occurred in 26 cases (60.5%). In 9 cases (20.9%) current occurence of intraspinal extradural and intradural communicating branches in the spinal canal were observed. Multiple extradural rami communicantes were observed in 6 cases (13.95%), including the simultaneous occurrence of multiple intradural and extradural ones in 5 cases (11.6%). CONCLUSIONS: This study allowed us to identify and describe current occurence of intraspinal extradural and intradural communicating branches in 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. The reliance of their incidence of the type of plexus was observed.