Ratings for “non-specific chronic, or chronic reoccurring, back pain” are based on the diagnosis-based impairment method whereby an impairment class, usually representing a range of impairment values within a cell of a grid, is selected by diagnosis and “specific criteria” (key factors). Within the impairment class, the default impairment value then can be modified using non-key factors or “grade modifiers” such as functional history, physical examination, and clinical studies using the net adjustment formula. The diagnosis of “nonspecific chronic, or chronic reoccurring, back pain” can be rated in class 0 and 1; the former has a default value of 0%, and the latter has a default value of 2% before any modifications. The key concept here is that the physician believes that the patient is experiencing pain, yet there are no related objective findings, most notably radiculopathy as distinguished from “nonverifiable radicular complaints.” If the individual is found not to have radiculopathy and the medical record shows that the patient has never had clinically verifiable radiculopathy, then the diagnosis of “intervertebral disk herniation and/or AOMSI [alteration of motion segment integrity] cannot be used.” If the patient is asymptomatic at maximum medical improvement, then impairment Class 0 should be chosen, not Class 1; a final whole person impairment rating of 1% indicates incorrect use of the methodology.

Spinal impairment evaluation includes determination of the presence or absence of alteration of motion segment integrity (AOMSI). The diagnosis-related estimate (DRE) method is the principal methodology used to evaluate spinal AOMSI impairment in the fourth and fifth editions of the AMA Guides to the Evaluation of Permanent Impairment ( AMA Guides ). In the AMA Guides, Sixth Edition, impairment ratings are calculated using the diagnosis-based impairment (DBI) method that uses five impairment classes determined by diagnoses and specific criteria, adjusted by consideration of non-key factors and grade modifiers. This article includes a correction of numbers in the AMA Guides, Sixth Edition, Figure 17-6. The following factors must be considered to determine if AOMSI is present: 1) flexion/extension radiographs are performed when the individual is at maximum medical improvement and are technically adequate; 2) the proper methodology is used in obtaining measurements of translation and angular motion; 3) normal translation and angular-motion thresholds consistent with the literature are used in determining AOMSI. Imaging modalities such as videofluoroscopy, digital fluoroscopy, and upright/motion magnetic resonance imaging cannot be used to establish an AOMSI permanent impairment using the AMA Guides . A number of technical factors can affect the image quality associated with measurements of AOMSI, including film centering, artifacts, poor edge resolution, endplate normal variations and spurring, and use of analog rather than digital radiography.

Nonspecific spinal pain and intervertebral disc herniations are common, and in evaluating spinal impairment physicians should carefully assess the significance of imaging findings, physical examination findings, and reports of limb pain. A case example illustrates key principles in assessing cervical pain in an individual with questionable arm complaints. A 62-year-old man had a slip and fall injury. Imaging studies revealed degenerative disc disease with disc bulges and without specific disc herniations according to the radiologists, but his physician reviewed magnetic resonance imaging (MRI) films and reported multiple disc herniations. The case example illustrates the significance of the finding of degenerative disc disease, determining whether to rate for “soft tissue and nonspecific conditions” or “motion segment lesions,” and assessing “nonverifiable radicular complaints.” The authors note that cervical degenerative disc “disease” is more aptly a radiologic diagnosis reflecting aging rather than a clinical syndrome and does not necessarily imply that the degenerative disc disease is the cause of the pain. To distinguish between nonverifiable radicular complaints without objective evidence of radiculopathy and unreliable vague complaints involving the extremity, evaluators should determine that the complaints are consistently and repetitively recognized in medical records and that they lie in the distribution of a single nerve root that the examiner can name. The diagnosis of “intervertebral disc herniation” cannot be made, and instead the “nonspecific chronic pain” diagnosis can be used. Nor can the diagnosis of alteration of motion segment integrity be used because the case lacks radiographically documented instability.

The sacroiliac joint (SIJ) is an accepted source of pain in patients with ankylosing spondylitis and other spondyloarthropathies, osteoarthritis, infections, and tumors, but the occurrence of isolated SIJ pain in the absence of such diseases is controversial. The term, sacroiliac joint dysfunction, which is used widely, describes pain from an SIJ that has no identifiable lesion but is presumed to have some mechanical etiology. Practitioners currently have no universally accepted gold standard for identifying a disc, facet joint, of SIJ as the pain generator. Treatment options for SIJ pain include medications, physical therapy, bracing, manual therapy, injections, radiofrequency neurotomy, and arthrodesis. Optimal management of patients with SIJ pain remains controversial. In the AMA Guides, Sixth Edition, a clinically established and causally related diagnosis of SIJ dysfunction is rated using the first row in Table 17-4. Surgery does not change the diagnosis or rating: The SIJ is not a motion segment of the lumbar spine, and SIJ fusion is not an alteration of motion segment integrity. Clinically, pain presumed to be from SIJ dysfunction is low back pain, so if this is the clinical diagnosis, the spine chapter in the AMA Guides, Fifth Edition, should be used. In such cases, the first step is to determine whether to use the diagnosis-related estimate or the range-of-motion method, and the article provides guidance about situations in which the use of each is appropriate.

Impairment evaluation of the spine has evolved notably since the 1958 publication by the American Medical Association of an article titled A Guide to the Evaluation of Permanent Impairment of the Extremities and Back. Significant differences exist among the editions of the AMA Guides to the Evaluation of Permanent Impairment ( AMA Guides ) currently in use, including the third edition, revised (1988), fourth (1993), fifth (2000), and sixth (2008) editions. This article reviews exemplary cases according to the instructions and methods of each edition, beginning with a table that summarizes spinal impairment criteria by edition of the AMA Guides . Another extensive table presents seven exemplar cases that demonstrate the differences in impairment ratings between the fourth, fifth, and sixth editions; each example is discussed in terms of different approaches taken in each of these editions. In the AMA Guides, Sixth Edition, the process of rating impairment was simplified by the elimination of the range of motion method. In the examples presented, the impairment values calculated using the sixth edition fall between those obtained using the fourth and fifth editions. Evaluating physicians must know the appropriate edition of the AMA Guides to use in each case and must understand the differences between them, particularly the changes included in the sixth edition.

The AMA Guides to the Evaluation of Permanent Impairment ( AMA Guides ), Sixth Edition, caused controversy with respect to changes in rating percentages. Impairment ratings in this edition are more specific than in previous editions and are intended to reflect lesser impairment in cases when symptomatology has improved with appropriate treatment. Grids in the AMA Guides, Sixth Edition, include impairment ratings for multiple-level conditions, so an alternative rating system (such as the range-of-motion method in the fifth edition) are not needed. The Diagnosis-related estimate (DRE) categories described in the fifth edition have been modified and expanded by the creation of regional grids that are used in the sixth edition to rate spinal impairments. The grids provide clearer categorization of many conditions and are consistent with clinical outcomes; ratings in the sixth edition reflect the results of treatment rather than the method of treatment. A significant difference in impairment ratings occurs between the fifth and sixth editions of the AMA Guides with respect to the classification of diagnoses of Alteration of Motion Segment Integrity, which includes fusion and, in the sixth edition, motion preserving technologies. A table compares the fifth and sixth editions for single-level spinal disease with or without radiculopathy and with or without surgery, including fusion.

The Diagnosis-related estimate (DRE) method is the principal methodology to evaluate spinal impairment, and alteration of motion segment integrity results at least in a DRE Category IV rating, based on a single-level fusion. Multilevel fusions are rated using the range-of-motion (ROM) method. Detailed examination of the medical literature identifies definitions of loss of motion segment integrity that differ from those in the AMA Guides to the Evaluation of Permanent Impairment, ( AMA Guides ), Fourth and Fifth Editions. Evaluators should note that the descriptions of certain figures were revised in the Errata to the Fifth Edition of the AMA Guides . Evaluators should note three key points from the AMA Guides: permanent impairment is based on findings at maximal medical improvement (MMI); motion in the spite must be abnormal to qualify for permanent impairment; and imaging results, by themselves, cannot be used to establish a DRE impairment rating. Overall, evaluators should consider flexion/extension radiographs that are technically adequate and taken at MMI; read and understand the Errata for Figures 15-3a, 15-3b, and 15-3c; and apply only normal translation and angular motion thresholds that are consistent with the scientific literature.

In 2005, the Food and Drug Administration (FDA) approved an artificial disc replacement (ADR), and physicians likely will be called on to evaluate permanent impairment in some patients who have been treated using an ADR. The AMA Guides to the Evaluation of Permanent Impairment, ( AMA Guides ), Fifth Edition, was published in 2000, before the approval of ADRs, and thus is silent about evaluating ADR-associated impairment. FDA based its approval on the results of a study in which the indications were tightly limited and for which the list of relative contraindications was quite long. One review of 100 consecutive lumbar spine surgery patients found that 95% had at least 1 contraindication to ADR. The AMA Guides recommends using the Diagnosis-related estimates (DRE) method, but some situations (eg, multilevel involvement in the same spinal region) warrant use of the range-of-motion (ROM) method. Assuming a single injury and one level of loss of the activities of daily living, the DRE is the correct method to rate the permanent impairment, and the authors recommend that ADR be accepted as the equivalent to loss of motion segment integrity, warranting a rating from CRE Category IV. ADR is in its infancy, and until the AMA Guides, Sixth Edition, is available, evaluators can rate one level ADR from DRE Category IV.

The AMA Guides to the Evaluation of Permanent Impairment ( AMA Guides ), Fifth Edition, defines a motion segment as “two adjacent vertebrae, the intervertebral disk, the apophyseal or facet joints, and ligamentous structures between the vertebrae.” The range of motion from segment to segment varies, and loss of motion segment integrity is defined as “an anteroposterior motion of one vertebra over another that is greater than 3.5 mm in the cervical spine, greater than 2.5 mm in the thoracic spine, and greater than 4.5 mm in the lumbar spine.” Multiple etiologies are associated with increased motion in the cervical spine; some are physiologic or compensatory and others are pathologic. The standard radiographic evaluation of instability and ligamentous injury in the cervical spine consists of lateral flexion and extension x-ray views, but no single pattern of injury is identified in whiplash injuries. Fluoroscopy or cineradiographic techniques may be more sensitive than other methods for evaluating subtle abnormal motion in the cervical spine. The increased motion thus detected then must be evaluated to determine whether it represents normal physiologic motion, normal compensatory motion, motion related to underlying degenerative disk and/or facet disease, or increased motion related to ligamentous injury. Imaging studies should be performed and interpreted as instructed in the AMA Guides .

The AMA Guides to the Evaluation of Permanent Impairment ( AMA Guides ), Fifth Edition, presents an impairment paradox: Single-level fusions rating using the Diagnosis-related estimates (DRE) method often result in higher impairment values than do multilevel cervical spine fusions. In the AMA Guides, Chapter 15, The Spine, the definition of Cervical Category IV (alteration of motion segment integrity or bilateral or multilevel radiculopathy) changed from the definition in the fourth edition for Cervicothoracic Category IV (loss of motion segment integrity or multilevel neurological compromise) because of changes in the definition of “alteration of motion segment integrity,” which now also includes surgical arthrodesis. This applies only for single-level fusions because the AMA Guides, states the range-of-motion (ROM) method is used in situations when “there is alteration of motion segment integrity (eg, fusions).” The AMA Guides, Fourth Edition, rated impairment on the basis of the injury, not the surgical procedure, and the maximum whole person permanent impairment for a patient with a single-level, single-sided cervical radiculopathy who had a discectomy and fusion would be 15%, but the minimum award for a similar patient rated using the DRE method is 25%. The author reports that, for the reasons outlined, evaluators should rate all cervical fusions, including single-level fusions, using the ROM method.

Spondylolisthesis generally is defined as an anterior or posterior slipping or displacement of one vertebra on another. A unilateral or bilateral defect of the pars interarticularis without displacement of the vertebra is known as spondylolysis or, less frequently, spondyloschisis. The AMA Guides to the Evaluation of Permanent Impairment ( AMA Guides ) notes that the two common types of spondylolisthesis are isthmic (related to the presence of spondylolysis and occurring in the immature spine) and degenerative spondylolisthesis (usually found in older individuals with degenerative changes, usually at the fourth or fifth lumbar vertebra). The AMA Guides classifies spondylolisthesis based on the etiology of the slip: congenital, isthmic, degenerative, traumatic, pathologic, and iatrogenic/postsurgical. In addition, grades ranging from I to V are assessed based on the severity of the displacement of the vertebra above on the vertebra below. Some of the confusion concerning terminology used in the AMA Guides regarding alteration of motion segment integrity arises because multiple different but similar terms exist, eg, those from the American Academy of Orthopaedic Surgeons vs the AMA Guides . The AMA Guides specifies that an x-ray finding of spondylolisthesis alone does not equal alteration of motion segment integrity, and a Diagnosis-related estimate (DRE) is the appropriate method for assessing spondylolisthesis (except in rare occurrences of multilevel spinal involvement, when the range-of-motion method is recommended).

A careful and thorough physical examination is a critical component of the spinal impairment evaluation. Two methods have been used for this evaluation, the Diagnosis-related estimates (DRE) method and the Range of Motion (ROM) method, but the AMA Guides to the Evaluation of Permanent Impairment ( AMA Guides ), Fifth Edition, states that “the DRE method is the principal methodology used to evaluate an individual who has had a distinct injury.” The DRE rating is based on objective findings at the time of evaluation and includes the following clinical findings: muscle spasm; muscle guarding; asymmetric spinal motion (previously called dysmetria); nonverifiable radicular pain; reflexes, neurological changes such as weakness or loss of sensation, atrophy, radiculopathy, and electrodiagnostic changes; alteration of motion segment integrity; cauda equina–like syndrome; and urodynamic tests. This article examines the definitions of the findings and discusses their use in the DRE method. For example, the AMA Guides, Fifth Edition, defines muscle spasm as a sudden, involuntary contraction of a muscle or group of muscles, and muscle spasm must be present at the time of a DRE-based evaluation; in the Fourth Edition, examiners used only a history of spasm. The AMA Guides, Fifth Edition also has different parameters, compared with the Fourth Edition, for determining atrophy.

Significant differences exist regarding spinal impairment rating among the Third Edition Revised, and the Fourth and Fifth Editions of the AMA Guides to the Evaluation of Permanent Impairment ( AMA Guides ). Table 1 summarizes the rating criteria used in these three editions. The AMA Guides, Third Edition Revised used only the method that was subsequently labeled the Range of Motion (ROM) Model or Method to assess impairment. The AMA Guides, Fourth Edition, introduced the Injury or Diagnosis-related estimates (DRE) Method, but it had a limited role, primarily as a differentiator, when a patient's final category of disability was in doubt. The AMA Guides, Fifth Edition retains both ROM and DRE, but they are termed methods rather than models. The DRE Method remains the principal means to evaluate an individual who has an injury, but changes were made regarding when and how it is used. In specified cases, the ROM Method is used to assess impairment not caused by an injury (eg, multilevel involvement, recurrent radiculopathy, or multiple pathologic episodes that produce alteration of motion segment integrity or radiculopathy). Table 2 presents seven exemplar cases that demonstrate the differences in impairment ratings among the three editions, and the text discusses the ratings and differences among the outcomes according to edition used.

Before the AMA Guides to the Evaluation of Permanent Impairment ( AMA Guides ), Fourth Edition, spine impairment was based on range of motion (ROM) testing combined with ratings for specific spine disorders and neurologic impairment. The AMA Guides, Fourth Edition, uses the Injury or Diagnosis-related Estimates (DRE) Model to rate spinal impairment. This model is based on history, physical examination (but not ROM unless ROM is used as a differentiator), and other test data. Table 71, DRE Impairment Category Differentiators, lists DRE impairment category differentiators and discusses the differences between ratings, choosing between differentiators, and their reliability and validity. Guarding is “a spasm of muscles to minimize motion or agitation of sites affected by injury or disease,” and spasm often is overreported by physicians who are unaware of its definition. Loss of reflexes, presenting as diminished or absent deep tendon reflexes, remains the hallmark of objective physical evidence. Decreased circumference is associated with atrophy. Loss of motion segment integrity is measured on lateral flexion and extension x-rays. Loss of bowel or bladder control suggests significant spinal cord injury. The final differentiator is bladder studies, measured using a cystometrogram and showing unequivocal neurologic compromise of the bladder with resulting incontinence.