Mechanical and physiological effects of dentatotomy

Abstract

The role of the dentate ligaments in the pathogenesis of myelopathy secondary to disease conditions that alter the normal biomechanics of the spinal canal was studied in 14 dogs. The effects of posterior cord elevation on somatosensory evoked potentials (SSEP's) and tension requirements were compared before and after dentate ligaments section in acute experiments. At levels of posterior elevation usually within the confines of the canine canal, the dentate ligaments were the most significant element increasing tension requirements and SSEP alternations. Human cadaver studies also showed an approximate 50% reduction of force after dentatotomy. These findings suggests that after dentate ligaments section the applied tension is distributed over a longer segments of the cord with a reduction in tension and disruption of axonal conduction at the level at which the force was applied.

The denticulate ligament: anatomy and functional significance

“…Our results also demonstrate similar forces that were necessary to create tautness in these ligaments with posterior distraction at various cord levels, although the upper cervical region tended to be somewhat more resistant to posterior distraction. Cusick, et al, 3 have shown in canines that the denticulate ligaments were the most significant element increasing tension requirements and decreasing conduction of evoked potentials with posterior dislocation of the spinal cord. Panjabi and White 16 have described axial and transverse components of the denticulate ligament with the former resisting axial tensions and the latter holding the cord in the center of the spinal canal, therefore limiting anterior and posterior motion.…”

“…Many authors have, however, attributed a role to these structures in stabilization of the spinal cord within the spinal canal. 3,5,8,10,14,16,22,25 These 20 to 21 paired ligaments are pia-arachnoid extensions surrounding a collagen core that attach the lateral spinal cord to the spinal dura mater. They conveniently separate dorsal from ventral rootlets and divide the spinal canal into posterior and anterior compartments (Fig.…”

The Amelioration of Symptoms in Cervical Spinal Stenosis with Spinal Cord Deformation Through Specific Chiropractic Manipulation: A Case Report with Long-Term Follow-Up

“…7,8 There are several studies which suggest that tensile forces transmitted to the cord through its dural and dentate ligament attachments play an important role in the generation of the neurological signs and symptoms seen clinically. [9][10][11] It is likely that all of these mechanisms play a role in the neurological compromise and that symptoms are generated through multifactorial pathophysiology. 6 Given the lack of understanding about the cause and mechanisms that generate symptoms in CSS, it is not surprising that there is also controversy and a lack of data concerning the natural history of CSS, as well as the longterm benefits of treatment.…”

Posterior Osteophyte Evolution and its Impact in Cervical Spondylosis: A Literature Review

“…This non-restoration of the normal contour of the cervical spinal cord in antero-posterior direction seen in MRI scans even after removal of the spondylotic bar is probably due to the above fibrosis of the dentate ligaments [35]. This fibrosis represents a physiological response to chronically raised levels of stress in these tissues [36]. Thus a spondylotic bar can increase dentate tension by displacing the spinal cord dorsally and also increase dentate tension by interfering locally with dural stretch during neck flexion with the resultant stress being transmitted to the spinal cord.…”