Abstract
Background and Study Aims A great number of unsuccessful intervertebral herniated disk surgeries in the lumbosacral
region have highlighted the importance of a comprehensive knowledge of the different
types of nerve root anomalies. That knowledge gained by anatomical studies (and intraoperative
findings) might contribute to better results. In our study we focused on intraspinal
extradural lumbosacral nerve root anomalies and their possible role in radiculopathy.
Material and Methods The study was performed on 43 cadavers within 24 hours after death (32 men and 11
women). Bodies were dissected in the prone position, and a laminectomy exposed the
entire spinal canal for the bilateral examination of each spinal nerve root from its
origin to its exit through the intervertebral foramen or sacral hiatus. Uncommon extradural
features in the lumbosacral region were pursued and documented. The spinal dural sac
was also opened, aimed at recognizing the normotyped, prefixed, or postfixed type
of plexus.
Results A total of 20.93% of anomalies of extradural lumbosacral nerve root origins were
observed, with the normotyped plexus prevailing. We observed atypical spacing of exits
of lumbosacral roots (four cases), two roots leaving one intervertebral foramen (one
case), extradural anastomoses (two cases), and missing extradural nerve root courses
(two cases). The results were differentiated according to the normotyped, prefixed,
or postfixed plexus type.
Conclusion Results of similar studies dealing with anomalies of lumbosacral nerve roots were
aimed at improving the results of herniated disk surgeries because ∼ 10% of misdiagnoses
are related to ignorance of anatomical variability. Our observations may help explain
the differences between the clinical picture and generally accepted anatomical standards.
Keywords
spinal nerve root - lumbosacral - extradural course
