Conjoined lumbosacral nerve roots compromised by disk herniation: Sagittal shoulder sign for the preoperative diagnosis

Chang Ho Kang, Myung Jin Shin, Sung Moon Kim, Sang Hoon Lee, Hee Kyung Kim, Jeong Ah Ryu, Choon Sung Lee, Sam Soo Kim

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Objective: The objective was to determine the importance of the "sagittal shoulder sign" on magnetic resonance (MR) images for the diagnosis of conjoined lumbosacral nerve roots (CLNR) that are compromised by herniated disks. Materials and methods: Magnetic resonance images of 11 patients (6 men and 5 women; age range, 25-71 years; average age, 48.7 years) with surgically proven CLNR, which was compromised by herniated disks, were retrospectively evaluated by two musculoskeletal radiologists. MR images were evaluated for the presence or absence of the sagittal shoulder sign-a vertical structure connecting two consecutive nerve roots and overlying disk on the sagittal MR images. The radiologists noted the type of accompanying disk herniation and bony spinal canal changes, as well as other characteristic MR features of CLNR, the common passage of two consecutive nerve roots through the neural foramen on axial MR images. Results: The sagittal shoulder sign was identified with a mean frequency of 90.9% by the two observers (in 10 of 11 patients). The common passage of two consecutive nerve roots through the neural foramen on axial MR images was identified with a mean frequency of 59.1% (in 7 and 6 out of 11 patients, by observers 1 and 2, respectively). Good interobserver agreement for the sagittal shoulder sign was present (k=0.621, p<0.05). Conclusion: Observation of the sagittal shoulder sign may prove helpful for diagnosing CLNR in patients with disk herniation. In particular, this sign appears to be useful when there is no evidence of CLNR on axial MR images.

Original languageEnglish
Pages (from-to)225-231
Number of pages7
JournalSkeletal Radiology
Volume37
Issue number3
DOIs
Publication statusPublished - 2008 Mar

Keywords

  • Abnormalities
  • Intervertebral disk displacement
  • Lumbosacral region
  • Magnetic resonance imaging
  • Spinal nerve roots

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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