Does the Percutaneous Dorsal Stabilization Technique for Spinal Fracture Fixation have a Favorable (Protective) Effect on the Muscular-stabilization System of the Spine? An EMG Consideration of The Supraspinous-Ligament-Reflex

Presented at SMISS Annual Forum 2018
By Rene Grass Prof DR. Med
With Jaroslaw Pyrc MD,

Disclosures: Rene Grass Prof DR. Med None Jaroslaw Pyrc MD None,

Introduction:

Reflex-linked muscular co-contractions of the autochthonic anterior and posterior muscles are the major stabilization mechanisms of spine. A variety of sensory receptors are present in the spinal ligaments. A mechanoreceptor (situated in the supraspinous ligament) activated by ligament distraction, recruits multifidus muscle response through an unconditioned reflex.

Aims/Objectives:

Determine if supraspinous mechanoreceptor reflex in the human spine could be preserved during percutaneous dorsal stabilization [PCDS] for fracture fixation.

Methods:

Experimental protocol and purpose of study approved by the ethic committee of the C.G.Carus Faculty. Intraoperative stimulation of the supraspinous ligament mechanoreceptor and EMG recording of the multifidus muscle response in patients undergoing PCDS for thoracolumbar fractures. 20 patients with thoracolumbar fractures (AO A3.1-fractures) (Frankel E) underwent PCDS. Bipolar needle electrode stimulation of supraspinous ligament one level above the fracture. EMG-recording of multifidus response bilaterally: A. fracture level [FL] B. segment above C. segment below fracture level. Response qualified as yes or no. EMG testing at the beginning of the operation (FREE) and after completed dorsal instrumentation [INSTRUMENTED]

Results:

20 (9 male/11 female) patients, mean age 55.4 (15-87) years, AO-A3. 1 fractures: Th 10 [1], Th12 [4], L1 [8] and L2 [6]. FREE condition: EMG response from multifidus was recorded at level A.-C. in all patients bilaterally (Yes: 100%). INSTRUMENTED condition: EMG response from multifidus was recorded and bilaterally at level A. and B. in all patients. At level C. 6/20 patients showed multifidus signal only unilaterally, the remaining 14 patients bilaterally (Yes: 87%).

Conclusions:

Electrical stimulation of one supraspinous ligament recruits multifidus muscle response in more than one lumbar motion segment. During PCDS, careful and blunt soft tissue dissection seems to preserve the function of the supraspinous ligament-reflex-arc and seems to preserve a major (=muscular) stabilizing mechanism of the spine.