Louisiana Administrative Code › Title 40 - LABOR AND EMPLOYMENT › Part I - Workers' Compensation Administration › Subpart 2 - Medical Guidelines › Chapter 22 - Neurological and Neuromuscular Disorder Medical Treatment Guidelines › Subchapter B - Thoracic Outlet Syndrome › Section I-2223 - Follow-up Diagnostic Imaging and Testing Procedures

Current through Register Vol. 50, No. 6, June 20, 2024
A. Cervical computed axial tomography or
					 magnetic resonance imaging (ct/mri) are generally accepted, well-established
					 procedures indicated to rule out cervical disc or other cervical spine
					 disorders when clinical findings suggest these diagnoses. It should not be
					 routinely performed for TOS. MRI is the preferred test over a CT unless a
					 fracture is suspected, and then CT may be superior to MRI. CT/MRI is not
					 indicated early unless there is a neurological deficit and/or the need to rule
					 out a space- occupying lesion, such as a tumor. Repeat cervical MRI is not
					 indicated for TOS. If cervical spine injury is confirmed, refer to the OWCA's
Cervical Spine Injury Medical Treatment Guidelines
. If a
					 cervical spine disorder is not suspected, conservative therapy as indicated in
					 Section F, Non-operative Procedures should be done for at least 8 to 12 weeks,
					 prior to ordering an MRI for persistent symptoms.
B. Electrodiagnostic Studies
1. Electromyography/Nerve Conduction
					 Velocities (EMG/NCV) is a generally accepted, well-established procedure.
					 EMG/NCV is primarily indicated to rule out other nerve entrapment syndromes
					 such as carpal tunnel or cubital tunnel syndrome when indicated by clinical
					 examination, or to establish true neurogenic TOS. Most cases of non-specific
					 TOS have normal electrodiagnostic studies, but EMG/NCV should be considered
					 when symptoms have been present for approximately three months or if the
					 patient has failed eight weeks of conservative therapy. EMG/NCV may also be
					 performed to rule out other disorders. Somato-sensory evoked potentials
					 (SSEPs), F waves and NCV across the thoracic outlet have no diagnostic value
					 and should not be performed. The diagnosis is usually made by comparison to the
					 normal extremity. For bilateral disease, each EMG lab must establish its own
					 absolute limits of latency and amplitude from volunteer controls so that
					 measurements exceeding these limits can be noted.
2. Criteria for True Neurogenic TOS
a. reduction of the ulnar sensory nerve
					 action potential to digits (usually less than 60 percent of unaffected side);
					 or
b. medial antebrachial sensory
					 action potential which is low or absent compared to the unaffected side;
					 or
c. reduction of the median
					 M-wave amplitude (usually less than 50 percent of unaffected side);
					 or
d. needle EMG examination
					 reveals neurogenic changes in intrinsic hand muscles and the abductor pollicus
					 brevis muscle.
3.
					 Portable automated electrodiagnostic device: (also known as surface EMG) is not
					 a substitute for conventional EMG/NCS testing in clinical decision-making, and
					 therefore, is not recommended.
4.
					 Quantitative Sensory Testing (QST). Research is not currently available on the
					 use of QST in the evaluation of TOS. QST tests the entire spectrum of the
					 neurological system including the brain. It is not able to reliably distinguish
					 between organic and psychogenic pathology and therefore, is not
					 recommended.