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Division 1 - Chapter 9 part3

Chapter 9 - Part III The Spine 110

Part III

The Spine

Part III - Introduction

The medical examiner should:

  • obtain a comprehensive, accurate medical history and review all relevant available records;
  • include in the assessment report a comprehensive description of current symptoms and their relationship to daily activities, detailed findings on physical examination, and all findings of relevant diagnostic and ancillary tests;
  • indicate how the impairment assessment was calculated by reference to the relevant tables.

For the same condition, WPI ratings from Table 9.7: Lower Extremity Function and/or Table 9.14: Upper Extremity Function , are not normally combined with WPI ratings from Table 9.15: Cervical Spine, Table 9.16: Thoracic Spine, or Table 9.17: Lumbar Spine.

However, the special procedure set out below applies where there is spinal cord injury with neurological sequelae (that is, corticospinal tract involvement).

Step 1

Assess (where applicable):

1.1. Lower limb impairment using Table 9.7;

1.2. Upper limb impairment using Table 9.14;

1.3. Bladder/Urological dysfunction using Table 12.7: Neurological Impairment of

the Urinary System (Chapter 12 - The Neurological System);

1.4. Anorectal dysfunction using Table 12.8: Neurological Impairment of the

Anorectal System (Chapter 12 - The Neurological System);

1.5. Sexual dysfunction using Table 12.9: Neurological Impairment Affecting

Sexual Function (Chapter 12 - The Neurological System);

1.6. Respiratory dysfunction (for example, with cervical spinal cord injuries) using

Table 12.6: Neurological Impairment of the Respiratory System (Chapter 12 - The Neurological System).

Step 2

Combine the relevant impairments from 1-6 in Step 1 above, as applicable.

Step 3

Then combine the WPI from the above procedure with the relevant WPI from Table 9.15, Table 9.16 or Table 9.17 (Diagnosis-Related Estimates) to obtain the final WPI.

For injuries not involving spinal cord damage but resulting in nerve root involvement/radiculopathy, use Table 9.15, Table 9.16 or Table 9.17, but do not combine with WPI ratings from Tables 9.7 or 9.14.

Except where the SAME nerve is involved, WPI ratings from Table 9.15, Table 9.16 and Table 9.17 (where relevant) may be combined with WPI ratings under the following tables:

Where there is brachial plexus involvement, WPI ratings from Table 9.15: Cervical Spine - Diagnosis-Related Estimates may not be combined with WPI ratings under Table 9.13.1: Cervical Nerve Root Impairment.

Definitions of Clinical Findings for Diagnosis-Related Estimates in Assessing Spinal Impairment are used when assessing impairments of the spine under Table 9.15, Table 9.16 and Table 9.17.

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Part III - Definitions of Clinical Findings for Diagnosis-Related Estimates in Assessing Spinal Impairment

These definitions are taken from the American Medical Association's Guides to the Evaluation of Permanent Impairment (5th edition, 2001).

Alteration of Motion Segment Integrity - motion segment alteration can be either loss of motion segment integrity (increased translational or angular motion), or decreased motion secondary to developmental fusion, fracture healing, healed infection, or surgical arthrodesis. An attempt at arthrodesis may not necessarily result in a solid fusion but may significantly limit motion at a motion segment. Motion of the individual spine segments cannot be determined by a physical examination but is evaluated with flexion and extension roentgenograms. When routine x-rays are normal and severe trauma is absent, motion segment alteration is rare, and flexion and extension roentgenograms are indicated only if motion segment alteration is suspected from the individual's history or routine x-rays.

Asymmetry of Spinal Motion in one of the three principal planes is sometimes caused by muscle spasm or guarding. That is, if an individual attempts to flex the spine, he or she is unable to do so moving symmetrically: rather, the head or trunk leans to one side. To qualify as true asymmetric motion, the finding must be reproducible and consistent, and the examiner must be convinced that the individual is co-operative and giving full effort.

Atrophy is measured with a tape measure at identical levels on both limbs. For reasons of reproducibility, the difference in circumference should be 2cm or greater in the thigh, and 1cm or greater in the arm, forearm, or leg.

Cauda equina syndrome is manifested by bowel or bladder dysfunction, saddle anaesthesia and variable loss of motor and sensory function in the lower extremities. Individuals with cauda equina syndrome usually have loss of sphincter tone on rectal examination and diminished or absent bladder, bowel, and lower limb reflexes.

Electrodiagnostic Verification of Radiculopathy. Unequivocal electrodiagnostic evidence of acute nerve root pathology includes the presence of multiple positive sharp waves or fibrillation potentials in muscles innervated by one nerve root. However, the quality of the person performing and interpreting the study is critical. Electromyography should be performed only by a physician qualified by reason of education, training, and experience in these procedures. Electromyography does not detect all compressive radiculopathies and cannot determine the cause of the nerve root pathology. On the other hand, electromyography can detect noncompressive radiculopathies, which are not identified by imaging studies.

Loss of Motion Segment Integrity is defined as an anteroposterior motion of one vertebra over another that is greater than 3.5mm in the cervical spine, greater than 2.5mm in the thoracic spine, and greater than 4.5mm in the lumbar spine. Alternatively, it is defined as a difference in the angular motion of two adjacent motion segments greater than 15° at L1-2, L2-3 and L3-4, greater than 20? at L4-5 and greater than 25° at L5-S1. In the cervical spine, it is also defined as motion at one level that is more than 11° greater than at either adjacent level.

Muscle Guarding is a contraction of muscle to minimise motion or agitation of the injured or diseased tissue. It is not true muscle spasm because the contraction can be relaxed. In the lumbar spine, the contraction frequently results in loss of the normal lumbar lordosis, and it may be associated with reproducible loss of spinal motion.

Muscle spasm is a sudden, involuntary contraction of a muscle or group of muscles. Paravertebral muscle spasm is common after acute spinal injury but is rare in chronic back pain. It is occasionally visible as a contracted paraspinal muscle but is more often diagnosed by palpation (a hard muscle).

To differentiate true muscle spasm from voluntary muscle contraction, the individual should not be able to relax the contractions. The spasm should be present standing, as well as in the supine position, and frequently causes a scoliosis. The physician can sometimes differentiate spasm from voluntary contraction by asking the individual to place all his or her weight first on one foot, and then the other, while the physician gently palpates the paraspinous muscles. With this manoeuvre, the individual normally relaxes the paraspinal muscles on the weight-bearing side. If the examiner witnesses this relaxation, it usually means that true muscle spasm is not present.

Nonverifiable Radicular Root Pain is pain that is in the distribution of a nerve root but has no identifiable origin (that is, there are no objective physical, imaging, or electromyographic findings).

Radiculopathy is significant alteration in the function of a nerve root or nerve roots, and is usually caused by pressure on one or several nerve roots. The diagnosis requires a dermatomal distribution of pain, numbness, and/or paraesthesia in a dermatomal distribution. A root tension sign is usually positive. A diagnosis of herniated disc must be substantiated by an appropriate finding on an imaging study. The presence of findings on an imaging study is insufficient to make the diagnosis of radiculopathy. There must also be clinical evidence as described above.

Reflexes may be normal, increased, reduced, or absent. For reflex abnormalities to be considered valid, the involved and normal limb(s) should show marked asymmetry between arms or legs on repeated testing. Once lost because of previous radiculopathy, a reflex rarely returns. Abnormal reflexes such as Babinski signs or clonus may be signs of corticospinal tract involvement.

Urodynamic Tests. Cystometrograms are useful in individuals where a cauda equina syndrome is possible but not certain. A normal cystometrogram makes the presence of a nerve-related bladder dysfunction unlikely. Occasionally, more extensive urodynamic testing is necessary.

Weakness and Loss of Sensation. To be valid, the sensory findings must be in a strict anatomic distribution (that is, follow dermatomal patterns). Motor findings should also be consistent with the affected nerve structure(s). Significant, long-standing weakness is usually accompanied by atrophy.

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Part III - Multi-level fractures involving the spinal canal

For fractures involving the spinal canal on more than one level, as distinct from the spinous processes or facet joints, the assessment made under Tables 9.15, 9.16 or 9.17 is to be adjusted as follows:

  • where there are multi-level fractures but no associated neurological compromise:
  • increase the assessment under Tables 9.15, 9.16 or 9.17 by one level;
  • where there are multi-level fractures and associated neurological compromise:
  • increase the assessment under Tables 9.15, 9.16 or 9.17 by two levels.

The adjustment, by one or two levels, as applicable, may be made only once under each Table.

The adjusted WPI assessment may not exceed the maximum WPI rating available in each individual table.

 

9.15 Cervical Spine - Diagnosis-Related Estimates

Table 9.15: Cervical Spine - Diagnosis-Related Estimates

% WPI

Criteria

0

  • No significant clinical findings, no muscular guarding, no documented neurological impairment, no significant loss of motion segment integrity, no other indication of impairment related to injury or illness;

or

  • No fractures.

8

  • Clinical history and examination findings compatible with specific injury. Findings may include: muscle guarding or spasm; asymmetric loss of range of motion or nonverifiable radicular complaints defined as complaints of radicular pain without objective findings.
  • No alteration of structural integrity;

or

Clinically significant radiculopathy and radiologically demonstrated disc herniation consistent with the radiculopathy (improved following non-operative treatment);

or

Fractures:

  • Compression fracture of one vertebral body of less than 25%;
  • Posterior element fracture without dislocation - healed without loss of structural integrity or radiculopathy;
  • Spinous or transverse process fracture with displacement.

18

Significant signs of radiculopathy, such as pain and/or sensory loss in a dermatomal distribution, loss or alteration of relevant reflex(es), loss of muscle strength, or unilateral atrophy compared with the unaffected side, measured at the same distance above or below the elbow: the neurological impairment may be verified by electrodiagnostic findings;

or

Clinically significant radiculopathy and radiologically verified disc herniation consistent with the radiculopathy, or with improved radiculopathy following surgery;

or

Fractures:

  • Compression fracture of one vertebral body of 25% to 50% - healed without loss of structural integrity, with or without radiculopathy;
  • Posterior element fracture with displacement disrupting the spinal canal - healed without loss of structural integrity, with or without radiculopathy.

Note: In the case of fractures, differentiation from a congenital or developmental condition should be accomplished, if possible, by examining pre-injury roentgenograms, if available, or by a bone scan performed after the onset of the condition.

28

  • Alteration of motion segment integrity (at least 3.5mm of translation of one vertebra on another or angular motion of more than 11° greater than at each adjacent level).
  • Bilateral or multilevel radiculopathy with radiologically verified disc herniation consistent with the radiculopathy.
  • Loss of motion of a motion segment due to a developmental fusion or successful or unsuccessful attempt at surgical arthrodesis;

or

Compression fracture of one vertebral body of more than 50% without residual neural compromise.

38

  • Significant upper extremity impairment requiring the use of upper extremity external functional or adaptive device(s).
  • Total neurological loss at a single level or severe, multilevel neurological dysfunction;

or

Structural compromise of the spinal canal with severe upper extremity motor and sensory deficits but without lower extremity involvement.

 

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9.16 Thoracic Spine - Diagnosis-Related Estimates

Table 9.16: Thoracic Spine - Diagnosis-Related Estimates

% WPI

Criteria

0

  • No significant clinical findings, no muscular guarding, no documented neurological impairment, no significant loss of motion segment integrity, no other indication of impairment related to injury or illness;

or

  • No fractures.

8

  • History and examination findings compatible with a specific injury or illness. Findings may include: significant muscle guarding or spasm; asymmetric loss of range of motion (dysmetria); or nonverifiable radicular complaints, defined as complaints of radicular pain without objective findings.
  • No alteration of motion segment integrity;
  • or

Herniated disc at the level and on the side that would be expected from objective clinical findings, but without radicular signs following conservative treatment;

or

Fractures:

  • Compression fracture of one vertebral body of less than 25%;
  • Posterior element fracture without dislocation - healed without alteration of motion segment integrity or radiculopathy;
  • Spinous or transverse process fracture with displacement, but without a vertebral body fracture.

18

Ongoing neurological impairment of the lower extremity related to a thoracolumbar injury, documented by alteration of motor and sensory functions, altered reflexes, or findings of unilateral atrophy above or below the knee related to no other condition, or verified by electrodiagnostic testing;

or

Clinically significant radiculopathy and radiologically verified disc herniation consistent with the radiculopathy, or with radiculopathy following surgery;

or

Fractures:

  • Compression fracture of one vertebral body of 25% to 50% - healed without alteration of structural integrity;
  • Posterior element fracture with mild displacement disrupting the canal - healed without alteration of structural integrity.

Note: Differentiation from a congenital or developmental condition should be accomplished, if possible, by examining pre-injury roentgenograms, if available, or by a bone scan performed after the onset of the condition.

23

  • Alteration of motion segment integrity (at least 2.5 mm translation of one vertebra on another)
  • Bilateral or multilevel radiculopathy with radiologically verified disc herniation consistent with the radiculopathy

or

Compression fracture of one vertebral body of more than 50% without residual neural compromise

28

  • Significant signs of radiculopathy, such as dermatomal pain and/or in a dermatomal distribution, sensory loss, loss of relevant reflex(es), loss of muscle strength or measured unilateral atrophy above or below the knee compared to measurements on the contralateral side at the same location (may be verified by electrodiagnostic findings).
  • Alteration of motion segment integrity (at least 2.5mm translation of one vertebra on another);

or

Compression fracture of one vertebral body by more than 50% with neural motor compromise, but not bilateral involvement. In that instance, refer notes concerning corticospinal tract impairment evaluation (see page 110, Part III - Introduction).

 

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9.17 Lumbar Spine - Diagnosis-Related Estimates

Table 9.17: Lumbar Spine - Diagnosis-Related Estimates

% WPI

Criteria

0

  • No significant clinical findings, no observed muscle guarding or spasm, no documented neurological impairment, no documented alteration in structural integrity, and no other indication of impairment related to injury or illness;

or

  • No fractures.

8

  • Clinical history and examination findings compatible with a specific injury. Findings may include: significant muscle guarding or spasm; asymmetric loss of range of motion; or nonverifiable radicular complaints, defined as complaints of radicular pain without objective findings.
  • No alteration of the structural integrity and no significant radiculopathy;

or

Prior clinically significant radiculopathy and radiologically demonstrated disc herniation, consistent with the radiculopathy, but radiculopathy no longer present following conservative treatment;

or

Fractures:

  • Compression fracture of one vertebral body of less than 25%;
  • Posterior element fracture without dislocation (not developmental spondylolysis) that has healed without alteration of motion segment integrity;
  • Spinous or transverse process fracture with displacement without a vertebral body fracture, with no disruption of the spinal canal.

13

Significant signs of radiculopathy, such as dermatomal pain and/or in a dermatomal distribution, sensory loss, alteration of relevant reflex(es), loss of muscle strength or measured unilateral atrophy above or below the knee compared to measurements on the contralateral side at the same location (may be verified by electrodiagnostic findings);

or

History of a herniated disc at the level and on the side consistent with objective clinical findings, associated with radiculopathy, or employees who have had surgery for radiculopathy but are now asymptomatic;

or

Fractures:

  • Compression fracture of one vertebral body of 25% to 50% - healed without alteration of structural integrity;
  • Posterior element fracture with displacement disrupting the spinal canal - healed without alteration of structural integrity.

23

  • Loss of motion segment integrity (at least 4.5mm of translation of one vertebra on another, or angular motion greater than 15° at L1-2, L2-3, and L3-4, greater than 20° at L4-5, and greater than 25° at L5-S1).
  • Complete, or near complete, loss of motion of a motion segment due to developmental fusion, or successful or unsuccessful attempt at surgical arthrodesis;

or

Compression fracture of one vertebral body of more than 50%, without residual neurological compromise.

28

Both radiculopathy and loss of motion segment integrity are present, with significant lower extremity impairment indicated by atrophy or loss of reflex(es), pain, and/or sensory changes within an anatomic distribution (dermatomal), verified by electrodiagnostic findings;

and

at least 4.5mm of translation of one vertebra on another or angular motion greater than 15° at L1-2, L2-3, and L3-4, greater than 20° at L4-5, and greater than 25° at L5-S1;

or

Compression fracture of one vertebral body of more than 50%, with unilateral neurological compromise.

 

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9.18 Fractures of the Pelvis

A WPI rating from Table 9.18 may be combined with WPI ratings from Table 9.15: Cervical Spine, Table 9.16: Thoracic Spine, and Table 9.17: Lumbar Spine.

Table 9.18: Fractures of the Pelvis

% WPI

Criteria (ONE required -

different conditions may be assessed separately)

0

Healed fracture:

  • without displacement or residual signs;
  • of one or both rami with displacement but without residual signs;
  • of ischium or ilium with displacement but without residual signs;
  • of coccyx with displacement but without residual signs;
  • of one pubic ramus with displacement, deformity and residual signs.

2

Healed fracture of ilium with displacement, deformity and residual signs.

5

Healed fracture of:

  • sacrum with displacement but without residual signs;
  • symphysis pubis without separation and without residual signs;
  • both pubic rami with displacement, deformity and residual signs.

Non-union of coccyx fracture.

Excision of coccyx.

10

Healed fracture of:

  • ischium with displacement of 2.5 cm or more, deformity and residual signs;
  • sacrum involving sacro-iliac joint.

15

Healed fracture of symphysis pubis with separation or displacement.

Evaluate in accordance with

Table 9.4

Fracture involving acetabulum.


Contents | Back | Next

Acknowledgments | Introduction | Tables and Figures
| Principles of Assessment

Division 1 | 1 - The Cardiovascular System | 2 - The Respiratory System
3 - The Endocrine System | 4 - Disfigurement and Skin Disorders
5 - Psychiatric Conditions | 6 - The Visual System
7 - Ear, Nose and Throat Disorders | 8 - The Digestive System
9 - The Musculoskeletal System | 10 - The Urinary System
11 - The Reproductive System | 12 - The Neurological System
13 - The Haematopoietic System

Division 2 | Division 3 | Appendix


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