Understanding and Interpreting Spinal Injuries in Compliance with the AMA Guides to the Evaluation of Permanent Impairment, Fifth Edition, 2001

(Recommendation: This is an overview. Please obtain and read a copy of the AMA Guides, Fifth Edition for a complete understanding of thisinformation and its use.)

Injuries to the spine cause (1) functional loss and (2) structural damage. Functional loss is the resultant effect of the injury on normal body systems. These include but are not limited to: muscular strength, joint mobility, coordination, and sensory perception. Structural damage includes the fracture of bones, dislocation or subluxation of spinal joints/segmental somatic dysfunction, and the tearing of joint capsules, discs, and other connective tissue. Other connective tissue includes supporting ligaments, tendons, muscles, nerves, and blood vessels.

Demonstrating the effect of spinal injuries is dependant upon the examination performed on the patient, the documentation of these findings and finally the appropriate interpretation and reporting of the information gathered.

EXAMINATION:

The examination should confirm or deny the presence of functional loss and structural damage.

Functional Losses can be evaluated by measuring spinal ranges of motion, extremity strength, muscle spasm or guarding, muscular atrophy, reflexes, and dermatomal sensory loss. Other functional losses such as bowl and bladder dysfunction, corticospinal tract impairments, or spinal cord injuries must be added using the combined values chart (AMA Guides pp 604-606).

To adequately demonstrate structural damage, imaging studies should be performed. Plain film radiography, including flexion / extension views, provide evidence of fracture, instability, arthrosis, and loss of motion segment integrity (MSI). MRI / CT exams are more useful to demonstrate disc bulges and disc herniations which in turn strongly suggests the presence of nerve root or cord compression.

DOCUMENTATION:

Loss of Motion Segment Integrity must be demonstrated on flexion/extension radiographs. The AMA Guide, pages 378-379, describes a motion segment as two adjacent vertebrae and their related joints and ligamentous structures. Specific, normal motions are expected at different levels of the spine. Aberrancies in this normal motion can be evaluated by measuring losses in ranges of motion (subluxation / fixation, arthrosis and/or degeneration) or by demonstrating hypermobility and instability with Loss of Motion Segment Integrity.

Two types of MSI are explained: Translation and Angular Motion (saggital rotation).

• Translation loss is a measured amount of saggital sliding of one vertebra on another. For the cervical spine, a value greater than 3.5 millimeters of measured sliding is a loss of structural integrity (pp. 378, 379, 392, 394). For the thoracic spine, a value greater than 2.5 millimeters of measured sliding is a loss of structural integrity (pp. 378, 379, 389, 391). For the lumbar spine, a value greater than 4.5 millimeters of measured sliding is a loss of structural integrity (pp. 378, 379, 384, 387).
• Angular Motion is a measured amount of saggital rotation. For the cervical spine, a vertebra that moves 11 degrees greater than an adjacent motor unit is considered to be a loss of MSI (pp. 378, 379, 392, 394). For example: If C3 vertebra has 20 degrees of motion in relation to C4 and C4 has 5 degrees of motion in relation to C5 then C3-C4 motion segment has a loss of structural integrity (> 11 degrees). For the lumbar spine, MSI values are measured at the motion segment in question and not compared to adjacent motor units. For levels L1-L2, L2-L3, and L3-L4 a measured saggital rotation greater than 15 degrees is a loss of structural integrity. For level L4-L5 a measured saggital rotation greater than 20 degrees is a loss of structural integrity. For L5-S1 a measured saggital rotation greater than 25 degrees is a loss of structural integrity. The thoracic spine is not discussed in the AMA Guide for saggital rotation measurement. Methods for measuring MSI are demonstrated in tables 15-3a,b and c, pp. 378-379.

INTERPRETATION:

(DRE) Diagnosis Related Estimates Method of Assigning Impairment Rating Based on the AMA Guide to Permanent Impairment, 2001 pp. 373-431.

“The DRE method is the principal methodology used to evaluate an individual who has a distinct injury” (pp. 379)

Cervical Spine (pp. 392-394)

Category I (0%)

• No significant clinical findings
• No muscle spasm or guarding
• No documentable neurological impairment
• No alteration in structural integrity
• No fractures

Category II (5-8%)

• History and exam relevant to a specific injury

May include:

• Muscle spasm
• Asymmetrical loss of range of motion
• Complaints of radiculopathy without objective findings
• No alteration of structural integrity

Or:

• Significant radiculopathy
• Disc herniation at expected site verified by imaging study
• Patient improved after nonoperative treatment

Or one of the following Fractures:

• Less than 25% compression of one vertebral body
• Healed posterior element fracture without loss of structural integrity or radiculopathy
• Spinous or transverse process fracture with displacement

Category III (15-18%)

Significant signs of radiculopathy:

• Dermatomal pain and/or sensory loss
• Loss of reflexes
• Loss of strength
• Muscular atrophy
• Neurologic impairment verified by electrodiagnosis

Or:

• Significant radiculopathy with disc herniation verified by imaging study
• Improvement of radiculopathy following surgery

Or one of the following Fractures:

• 25-50% compression of one vertebral body (healed without loss of structural integrity)
• Posterior element fracture with displacement into the spinal canal (healed without loss of structural integrity)

Category IV (25-28%)

• Bilateral or multilevel radiculopathy.
• Alteration in motion segment integrity determined from flexion extension radiographs as 3.5mm or greater of translation or angular motion 11 degrees greater than each adjacent level (radiculopathy need not be present).

Or:

• More than 50% compression of one vertebral body without residual neurological compromise.

Category V (35-38%)

• Significant impairment of the upper extremity requiring adaptive functional devices.
• Single level total neurologic loss.
• Multilevel neurological dysfunction.

Thoracic Spine (pp. 388-391)

Category I (0%)

• No significant clinical findings
• No muscle spasm or guarding
• No documentable neurological impairment
• No alteration in structural integrity
• No fractures

Category II (5-8%)

• History and exam relevant to a specific injury

May include:

• Muscle spasm
• Asymmetrical loss of range of motion
• Complaints of radiculopathy without objective findings
• No alteration of structural integrity

Or:

• Disc herniation at expected site verified by imaging study
• No radicular signs after nonoperative treatment

Or one of the following Fractures:

• Less than 25% compression of one vertebral body
• Healed posterior element fracture without loss of structural integrity or radiculopathy
• Spinous or transverse process fracture with displacement

Category III (15-18%)

Lower extremity neurologic impairment related to thoracolumbar injury documented by examination findings of:

• Loss of reflexes
• Loss of motor strength and/or sensory loss
• Muscular atrophy
• Neurologic impairment verified by electrodiagnosis

Or:

• Significant radiculopathy with disc herniation verified by imaging study
• Improvement of radiculopathy following surgery

Or one of the following Fractures:

• 25-50% compression of one vertebral body (healed without loss of structural integrity)
• Posterior element fracture with mild displacement into the spinal canal (healed without loss of structural integrity)

Category IV (20-23%)

• Bilateral or multilevel radiculopathy.
• Alteration in motion segment integrity determined from flexion / extension radiographs as 2.5mm or greater of translation of one vertebrae on another (radiculopathy need not be present).

Or:

• More than 50% compression of one vertebral body without residual neurological compromise.

Category V (25-28%)

• Impairment of the lower extremity demonstrated in category III and loss of structural integrity demonstrated in category IV.

Or:

• More than 50% compression of one vertebral body with unilateral neurological motor compromise (bilateral involvement-refer to corticospinal tract involvement)

Lumbar Spine (pp. 384-388)

Category I (0%)

• No significant clinical findings
• No muscle spasm or guarding
• No documentable neurological impairment
• No alteration in structural integrity
• No fractures

Category II (5-8%)

• History and exam relevant to a specific injury

May include:

• Muscle spasm
• Asymmetrical loss of range of motion
• Complaints of radiculopathy without objective findings
• No alteration of structural integrity

Or:

• Clinically significant radiculopathy with accompanying disc herniation at expected site verified by imaging study that has no radicular signs after nonoperative treatment

Or one of the following Fractures:

• Less than 25% compression of one vertebral body
• Healed posterior element fracture without loss of structural integrity, dislocation or radiculopathy
• Spinous or transverse process fracture with displacement without vertebral body fracture and without disruption of the spinal canal

Category III (10-13%)

Lower extremity neurologic impairment related to thoracolumbar injury document by examination findings of:

• Loss of reflexes
• Loss of motor strength and/or sensory loss
• Muscular atrophy
• Neurologic impairment verified by electrodiagnosis

Or:

• Radiculopathy with disc herniation verified by imaging study
• Post surgical asymptomatic radiculopathy

Or one of the following Fractures:

• 25-50% compression of one vertebral body (healed without loss of structural integrity)
• Posterior element fracture with displacement into the spinal canal (healed without loss of structural integrity)

Category IV (20-23%)

• Bilateral or multilevel radiculopathy.
• Alteration in motion segment integrity determined from flexion extension radiographs as 4.5mm or greater of translation of one vertebrae on another or angular motion of adjacent segment greater than: 15 degrees for L1, L2, and L3, 20 degrees at L4-L5, and 25 degrees at L5-S1 (radiculopathy need not be present).

Or:

• More than 50% compression of one vertebral body without residual neurological compromise.

Category V (25-28%)

• Radiculopathy demonstrated in category III and loss of motion segment integrity demonstrated in category IV.

Or:

• More than 50% compression of one vertebral body with unilateral neurological motor compromise

REPORTING:

Documentation is best presented in a narrative report.

Writing narrative reports can seem tedious, daunting, or downright scary. This doesn’t have to be. Complete examinations and complete record keeping makes report writing much simpler to do. The fact is that reports are necessary communication tools. Procrastination of or missing this important step in patient care will cause delays in reimbursement, require multiple explanations to patients about their diagnosis and treatment plans, and provide you with hours of dread.

Like any other form of communication, a report must have a purpose. Often times, one report may serve many purposes. Examples may include:

1. Documenting objective findings (for the file),
2. Explanation of procedures (for the insurance Co. or other responsible party),
3. Establishes a necessity for care (third party payers),
4. Establishes a reference point on patient condition (for the patient),
5. Demonstrates your credibility (for referrals).

Types of reports often presented are:

1. Initial Report
   History
   Exam findings
   Prognosis
   Plan
2. Interim Report
   Re-exam findings
   Changes in prognosis
   Plan
3. Final Report
   Final exam findings
   Residual-impairment
   Recommended long term care

A final few thoughts:
When presenting your findings in a report format, impairment ratings are very useful and at times even required. This is easily accomplished by using the DRE method.

Remember Loss of Motion Segment Integrity findings on flexion extension radiographs are by definition a category IV impairment (20% to 28% whole body impairment).

The rest of the health care community understands Segmental Somatic Dysfunction. We have called it Subluxation.