Korean J Pain.  2014 Oct;27(4):321-325. 10.3344/kjp.2014.27.4.321.

Anatomic Variations of Cervical and High Thoracic Ligamentum Flavum

• Yoon SP
• Kim HJ
• Choi YS

• KMID: 1802497
• DOI: http://doi.org/10.3344/kjp.2014.27.4.321

Abstract

BACKGROUND
Epidural blocks are widely used for the management of acute and chronic pain. The technique of loss of resistance is frequently adopted to determine the epidural space. A discontinuity of the ligamentum flavum may increase the risk of failure to identify the epidural space. The purpose of this study was to investigate the anatomic variations of the cervical and high thoracic ligamentum flavum in embalmed cadavers.
METHODS
Vertebral column specimens of 15 human cadavers were obtained. After vertebral arches were detached from pedicles, the dural sac and epidural connective tissue were removed. The ligamentum flavum from C3 to T6 was directly examined anteriorly.
RESULTS
The incidence of midline gaps in the ligamentum flavum was 87%-100% between C3 and T2. The incidence decreased below this level and was the lowest at T4-T5 (8%). Among the levels with a gap, the location of a gap in the caudal third of the ligamentum flavum was more frequent than in the middle or cephalic portion of the ligamentum flavum.
CONCLUSIONS
The cervical and high thoracic ligamentum flavum frequently has midline intervals with various features, especially in the caudal portion of the intervertebral space. Therefore, the ligamentum flavum is not always reliable as a perceptible barrier to identify the epidural space at these vertebral levels. Additionally, it may be more useful to insert the needle into the cephalic portion of the intervertebral space than in the caudal portion.

Keyword

epidural analgesia; epidural space; ligamentum flavum

MeSH Terms

Analgesia, Epidural
Cadaver
Chronic Pain
Connective Tissue
Epidural Space
Humans
Incidence
Ligamentum Flavum*
Needles
Spine

Figure

• 

  Fig. 1 Dissected cervical and high thoracic vertebral column examined anteriorly. Midline gaps of ligamentum flavum are shown.

• 

  Fig. 2 Classification of the midline gap in the ligamentum flavum. Type A is no gap throughout the entire length of LF. Type B is a gap in a portion of LF (B1: gap in the caudal third of LF, B2: gap in the middle third of LF, B3: gap in the cephalic third of LF). Type C is a midline gap throughout LF (C1: midline gap throughout the entire height of LF, C2: midline gap wider in the caudal third of LF, C3: midline gap with a fusion in the middle of the gap).

Reference

1. Heo BH, Pyeon TH, Lee HG, Kim WM, Choi JI, Yoon MH. Epidural infusion of morphine and levobupivacaine through a subcutaneous port for cancer pain management. Korean J Pain. 2014; 27:139–144. PMID: 24748942.

2. Blomberg RG, Jaanivald A, Walther S. Advantages of the paramedian approach for lumbar epidural analgesia with catheter technique. A clinical comparison between midline and paramedian approaches. Anaesthesia. 1989; 44:742–746. PMID: 2478045.

3. Joo Y, Moon JY, Kim YC, Lee SC, Kim HY, Park SY. A pressure comparison between midline and paramedian approaches to the cervical epidural space. Pain Physician. 2014; 17:155–162. PMID: 24658476.

4. Butterworth JF, Mackey DC, Wasnick JD. Spinal, epidural, & caudal blocks. Morgan & Mikhail's clinical anesthesiology. 5th ed. New York (NY): McGraw-Hill;2013. p. 953–956.

5. Lirk P, Kolbitsch C, Putz G, Colvin J, Colvin HP, Lorenz I, et al. Cervical and high thoracic ligamentum flavum frequently fails to fuse in the midline. Anesthesiology. 2003; 99:1387–1390. PMID: 14639154.

6. Lirk P, Moriggl B, Colvin J, Keller C, Kirchmair L, Rieder J, et al. The incidence of lumbar ligamentum flavum midline gaps. Anesth Analg. 2004; 98:1178–1180. PMID: 15041621.

7. Kim GS. Epidural block. Korean Pain Society. Textbook of pain medicine. 4th ed. Seoul: Shin-Won Publishing;2012. p. 565–574.

8. Williams A. The back. In : Standring S, editor. Gray's anatomy: the anatomical basis of clinical practice. 39th ed. Philadelphia (PA): Elsevier Churchill Livingstone;2005. p. 755.

9. Moore KL, Dally AF II, Agur AM. Joints of vertebral column. Clinically oriented anatomy. 6th ed. Philadelphia (PA): Lippincott Williams & Wilkins;2010. p. 466.

10. Harrison GR. Topographical anatomy of the lumbar epidural region: an in vivo study using computerized axial tomography. Br J Anaesth. 1999; 83:229–234. PMID: 10618934.

11. Misawa H, Ohtsuka K, Nakata K, Kinoshita H. Embryological study of the spinal ligaments in human fetuses. J Spinal Disord. 1994; 7:495–498. PMID: 7873846.

12. Zarzur E. Anatomic studies of the human ligamentum flavum. Anesth Analg. 1984; 63:499–502. PMID: 6711844.

13. Lirk P, Colvin J, Steger B, Colvin HP, Keller C, Rieder J, et al. Incidence of lower thoracic ligamentum flavum midline gaps. Br J Anaesth. 2005; 94:852–855. PMID: 15817710.

14. Hopwood D. Fixation and fixatives. In : Bancroft JD, Gamble M, editors. Theory and practice of histological techniques. 5th ed. Edinburgh: Churchill Livingstone;2002. p. 63–84.