Conjoined lumbosacral nerve roots: current aspects of diagnosis

Eur Spine J (2004) 13 : 147151DOI 10.1007/s00586-003-0634-8ORIGINAL ARTICLEJ. BttcherA. PetrovitchP. SrsA. MalichS. HusseinW. A. KaiserConjoined lumbosacral nerve roots:

current aspects of diagnosisReceived: 4 December 2002

Revised: 18 August 2003

Accepted: 29 August 2003

Published online: 22 November 2003

Springer-Verlag 2003J. Bttcher () A. Petrovitch A. Malich W. A. KaiserInstitute for Diagnostic

and Interventional Radiology,

Friedrich Schiller University Jena,

Bachstrasse 18, 07740 Jena, Germany

Tel.: [phone],

Fax: [phone],

e-mail: [email protected]. SrsDepartment of Neurology,

Westflische Wilhelms-Universitt Mnster,

Mnster, GermanyS. HusseinDepartment of Neurosurgery,

Medizinische Hochschule Hannover,

Hannover, GermanyAbstract Conjoined lumbosacral

nerve roots (CLNR) are the most

common anomalies involving the

lumbar nerve structures which can be

one of the origins of failed back syndromes. They can cause sciatica

even without the presence of a additional compressive impingement

(such as disc herniation, spondylolisthesis or lateral recess stenosis), and

often congenital lumbosacral spine

anomalies (such as bony defects) are

present at the conjoined sheaths.

This congenital anomaly has been reported in 14% of cadaver studies, but

myelographic or computed tomographic studies have revealed an incidence of approximately 4% only.

Diagnostic methods such as magnetic resonance imaging (MRI) are

helpful for determination of the exact

anatomical relations in this context.

We present five typical cases of conjoined nerve roots observed during a

1 year period, equivalent to 6% of

our out-patients without a history of

surgical treatment on the lumbar

spine. In all cases with suspicious radiological findings MRI or lumbar

myelography combined with CT and

multiplanar reconstructions is recommended.Keywords Conjoined nerve roots

MRI Lumbosacral spine anomaly

SciaticaIntroductionLumbosacral nerve roots are arranged strictly segmentally.

Deviations can be observed and are considered to be congenital in origin, arising during the fetal development of

spinal structures [2]. Most common are conjoined lumbosacral nerve roots (CLNR), which have been reported

in 14% of the cases in a post-mortem study [11]. Since the

first description in 1949 [22], about 120 cases of conjoined nerve roots have been published. Most had anomalies of the nerve roots L4S1. A very rare constellation is

bilateral CLNR [3], involving the roots of L4/L5 or L5/S1.

CLNR may be either asymptomatic or cause spontaneous

lumbar and radicular pain [6]. The presence of additional

abnormalities [16] or degenerative changes, such as disc

herniation or lateral recess stenosis [19, 21], support...