La. Admin. Code tit. 40 § I-2127

Current through Register Vol. 50, No. 9, September 20, 2024

Section I-2127 - Diagnostic Procedures

A. Diagnostic imaging is a generally accepted, well-established, and widely used diagnostic procedure when specific indications, based on history and physical examination, are present. Physicians should refer to individual OWCA guidelines for specific information about specific testing procedures.

1. Plain Film Radiography:

a. Description. A radiological finding in CRPS may be unilateral osteoporosis; however, osteoporosis may be absent in many cases. In CRPS-I, the osteoporosis may be rapid in progression. The disorder typically affects the distal part of an extremity such as a hand or foot, yet intermediate joints such as the knee or elbow may be involved.

b. Results. The radiological appearance of osteoporosis has been characterized as spotty or patchy. Although CRPS-I may exist in the absence of osteoporosis, the diagnosis of CRPS-I cannot be made solely on the basis of radiographic appearance or the osteoporosis alone.

2. Triple Phase Bone Scan:

a. Description. Radionucleotide imaging scintigraphy employing radio-pharmaceutical technetium coupled to a phosphate complex has been used to help facilitate the diagnosis of CRPS-1. It was hoped that a three-phase radionucleotide study would be selective in the face of demineralization of the bone as seen in CRPS-I. However there are many different types of conditions that can produce osteoporosis and a triple-phase bone scan does not distinguish between the causes of bone demineralization.

b. Results. Clinical information can be derived from each of the three phases of the bone scan following injection. In the early course of CRPS-I, there is an increased uptake seen during Phase 1. However, in the late course of the disease process, there can actually be a decreased uptake seen. In Phase 2, which reflects the soft tissue vascularity, an increased diffuse uptake may be appreciated during the early course of CRPS-I. During Phase 3, one will see a diffuse uptake of multiple bone involvement of the involved limb, reflecting the bone turnover secondary to osteoporosis. Negative bone scans may be found in up to 40 percent of patients clinically diagnosed with CRPS-I; however when positive it may help to confirm the diagnosis of CRPS-I.

B. Injections-diagnostic sympathetic

1. Description. Diagnostic sympathetic injections are generally accepted procedures to aid in the diagnosis of CRPS I and II and SMP. Sympathetic blocks lack specificity for CRPS I and II. Each diagnostic injection has inherent risk and risk versus benefit should always be evaluated when considering injection therapy. Since these procedures are invasive, less invasive or non-invasive procedures should be considered first. Selection of patients, choice of procedure, and localization of the level for injection should be determined by clinical information.

2. Special Considerations. Injections with local anesthetics of differing duration are required to confirm a diagnosis. In some cases, injections at multiple levels may be required to accurately diagnose pain. Refer to "Injections Therapeutic" for information on specific injections.

a. Since fluoroscopic and/or CT guidance during procedures is recommended to document technique and needle placement, an experienced physician should perform the procedure. The practitioner should have experience in ongoing injection training workshops provided by organizations such as the American Society of Interventional Pain Physicians (ASIPP) or Spine Intervention Society (SIS) and be knowledgeable in radiation safety. In addition, practitioners should obtain fluoroscopy training and radiation safety credentialing from their Departments of Radiology, as applicable.

3. Complications. Complications may include transient neurapraxia, nerve injury, inadvertent spinal injection, infection, venous or arterial vertebral puncture, laryngeal paralysis, respiratory arrest, vasovagal effects, as well as permanent neurological damage.

4. Contraindications. Absolute contraindications of diagnostic injections include: bacterial infection systemic or localized to region of injection, bleeding diatheses, hematological conditions, and possible pregnancy. Relative contraindications of diagnostic injections may include: aspirin/antiplatelet therapy (drug may be held for at least three days prior to injection).

5. Test Results. The interpretation of the test result is primarily based upon pain relief of 50 percent or greater. The diagnostic significance of the test result should be evaluated in conjunction with clinical information and further information can be obtained from functional reassessment performed by physical and/or occupational therapy or from results of other diagnostic procedures following a successful block.

a. Local anesthetics of different durations of action should be considered and could take the place of doing a "placebo" block (i.e. - procaine, lidocaine, marcaine). Pain relief should be at least 50 percent or greater for the duration of the local anesthetic. It should be noted that with CRPS-I it is not unusual for the relief to last longer than the duration of the local anesthetic. If a placebo block is done, the needle should not be placed down to the sympathetic chain nor should an injection of saline be done around the sympathetic chain. Contact with the sympathetic nerves by a needle or pressure on the chain by saline can cause a temporary sympathetic block and give a false positive placebo test. A "sham block" would be preferable to see if the patient is a placebo responder. Additionally, patients with definite CRPS-I can also be placebo responders. The fact that the patient responds positively to a placebo does not mean that he/she does not have CRPS-1. It merely means that the patient is a placebo responder. This increases the value of doing another confirmatory test.

i. Stellate Ganglion Block. For diagnosis and treatment of sympathetic pain involving the face, head, neck, and upper extremities secondary to CRPS-I and II. This block is commonly used for differential diagnosis and is the preferred treatment of CRPS-I pain involving the upper extremity Kuntz Fiber Blockade (T1-T3 sympathetic chain) on the affected side is necessary for upper extremity pain not responsive to stellate ganglion blockade.

(a). For diagnostic testing, use three blocks over a 3-14 day period. For a positive response, pain relief should be 50 greater or greater for the duration of the local anesthetic and pain relief should be associated with functional improvement.

ii. Lumbar Sympathetic Block. Useful for diagnosis and treatment of pain of the pelvis and lower extremity secondary to CRPS-I and II. This block is commonly used for differential diagnosis and is the preferred treatment of sympathetic pain involving the lower extremity. For diagnostic testing, use three blocks over a 3-14 day period. For a positive response, pain relief should be 50 percent or greater for the duration of the local anesthetic and pain relief should be associated with functional improvement.

iii. Phentolamine Infusion Test. An intravenous infusion of phentoalmine, an alpha 2 blocker, which results in generalized systemic sympatholysis. The infusion begins with intravenous saline for placebo control. For a positive response, pain relief should be 50 percent or greater and associated with functional improvement. This test aids in the diagnosis of Sympathetically Maintained Pain.

iv. Thoracic Sympathetic Block. Useful for abdominal or pelvic visceral pain secondary to CRPS I and II. Use the same guidance as for lumbar sympathetic Block.

C. Thermography (infrared stress thermography)

1. Description. A generally accepted procedure with some evidence to support its limited use. Infrared thermography may be useful for patients with suspected CRPS-I and II, and SMP. Thermography can distinguish abnormal thermal asymmetry of 1.0 degree Celsius which is not distinguishable upon physical examination. It may also be useful in cases of suspected small caliber fiber neuropathy and to evaluate patient response to sympatholytic interventions.

2. Special Considerations. The practitioner who supervises and interprets the thermographic evaluation shall follow recognized protocols and be board certified by one of the examining boards of the American Academy of Medical Infrared Imaging, American Academy of Thermology, or American Chiropractic College of Thermology.

3. Medications with anticholinergic activity (tricyclics, cyclobenzaprine, antiemetics, antipsychotics) may interfere with autonomic testing. The pre-testing protocol which includes cessation of specific medications therapy must be followed for accurate test results. Results of autonomic testing may be affected by peripheral polyneuropathy, radiculopathy or peripheral nerve injury, peripheral vascular disease, generalized autonomic failure, or by Shy-Drager syndrome.

4. Thermographic Tests. Functional autonomic stress testing may include any of the following methods:

a. Cold Water Stress Test (Cold Pressor Test). Paroxysmal cooling is strongly suggestive of vasomotor instability.

b. Warm Water Stress Test. Paroxysmal warming is strongly suggestive of vasomotor instability.

c. Digital infrared temperature monitoring should be used before and after sympathetic block where indicated to evaluate response to sympatholytic intervention.

D. Autonomic test battery

1. Description. Resting skin temperature (RST), resting sweat output (RSO), and quantitative sudomotor axon reflex test (QSART) are a recently developed test battery with some evidence to support its limited use in the diagnosis of CRPS-I. Prior authorization is required.

2. Special Considerations. Medications with anticholinergic activity (tricyclics, cyclobenzaprine, antiemetics, antipsychotics) may interfere with autonomic testing. Results of autonomic testing may be affected by peripheral polyneuropathy, radiculopathy or peripheral nerve injury, peripheral vascular disease, generalized autonomic failure, or by Shy-Drager syndrome.

3. Test Battery. These tests measure asymmetries in physiologic manifestations of autonomic activity between an affected limb and an unaffected contralateral limb. Skin temperature reflects vasomotor activity and sweat output measures sudomotor activity. The results of the three test components must be combined and scored. The battery of tests must include a measurement of each component (RST, RSO, and QSART).

a. Infrared Resting Skin Temperature (RST) provides thermographic measurements between the affected and unaffected limb. Generally, a 1 ° Celsius difference is significant.

b. Resting Sweat Output (RSO) measures an increase or reduction of 50 percent between the affected and unaffected limb.

c. Quantitative Sudomotor Axon Reflex Test (QSART) measures the sweat output elicited by iontophoretic application of acetylcholine. An increase or reduction of 50 percent between the affected and unaffected limb is significant.

E. Other Diagnostic Tests Not Specific for CRPS. The following tests and procedures are not used to establish the diagnosis of CRPS but may provide additional information. The following are listed in alphabetical order.

1. Electrodiagnostic Procedures. Electromyography (EMG) and Nerve Conduction Studies (NCS) are generally accepted, well-established and widely used for localizing the source of the neurological symptoms and establishing the diagnosis of focal nerve entrapments, such as carpal tunnel syndrome or radiculopathy, which may contribute to or coexist with CRPS II (causalgia). Traditional electrodiagnosis includes nerve conduction studies, late responses, (F-Wave, H-reflex) and electromyographic assessment of muscles with needle electrode examination. As CRPS II occurs after partial injury to a nerve, the diagnosis of the initial nerve injury can be made by electrodiagnostic studies. The later development of sympathetically mediated symptomatology however, has no pathognomonic pattern of abnormality on EMG/NCS. When issues of diagnosis are in doubt, a referral or consultation with a physiatrist or neurologist trained in electrodiagnosis is appropriate.

2. Laboratory Tests are generally accepted well-established and widely used procedures and can provide useful diagnostic and monitoring information. They may be used when there is suspicion of systemic illness, infection, neoplasia, or underlying rheumatologic disorder, connective tissue disorder, or based on history and/or physical examination. Tests include, but are not limited to:

a. Complete Blood Count (CBC) with differential can detect infection, blood dyscrasias, and medication side effects.

b. Erythrocyte sedimentation rate, rheumatoid factor, antinuclear antigen (ANA), human leukocyte antigen (HLA), and C-reactive protein can be used to detect evidence of a rheumatologic, infection, or connective tissue disorder, serum protein electrophoresis.

c. Thyroid, glucose and other tests to detect endocrine disorders.

d. Serum calcium, phosphorous, uric acid, alkaline phosphatase, and acid phosphatase can detect metabolic bone disease.

e. urinalysis for calcium, phosphorus, hydroxyproline, or hematuria;

f. Liver and kidney function may be performed for baseline testing and monitoring of medications; and

g. Toxicology Screen and/or Blood Alcohol Level if suspected drug or alcohol abuse.

3. Peripheral Blood Flow (Laser Doppler or Xenon Clearance Techniques): This is currently being evaluated as a diagnostic procedure in CRPS-I and is not recommended by the OWCA at this time.

a. Personality / Psychosocial / Psychiatric / Psychological Evaluation:

i. These are generally accepted and well-established diagnostic procedures with selective use in the upper extremity population, but have more widespread use in subacute and chronic upper extremity populations. Diagnostic testing procedures may be useful for patients with symptoms of depression, delayed recovery, chronic pain, recurrent painful conditions, disability problems, and for preoperative evaluation. Psychological/psychosocial and measures have been shown to have predictive value for postoperative response, and therefore should be strongly considered for use pre-operatively when the surgeon has concerns about the relationship between symptoms and findings, or when the surgeon is aware of indications of psychological complication or risk factors for psychological complication (e.g. childhood psychological trauma). Psychological testing should provide differentiation between pre-existing conditions versus injury caused psychological conditions, including depression and posttraumatic stress disorder. Psychological testing should incorporate measures that have been shown, empirically, to identify comorbidities or risk factors that are linked to poor outcome or delayed recovery.

ii Formal psychological or psychosocial evaluation should be performed on patients not making expected progress within 6 to 12 weeks following injury and whose subjective symptoms do not correlate with objective signs and test results. In addition to the customary initial exam, the evaluation of the injured worker should specifically address the following areas:

(a). employment history;

(b). interpersonal relationships-both social and work;

(c). patient activities;

(d). current perception of the medical system;

(e). current perception/attitudes toward employer/job

(f). results of current treatment

(g). Risk factors and psychological comorbidities that may influence outcome and that may require treatment.

(h). Childhood history, including history of childhood psychological trauma, abuse and family history of disability.

iii. Personality/psychological/psychosocial evaluations consist of two components, clinical interview and psychological testing. Results should help clinicians with a better understanding of the patient in a number of ways. Thus the evaluation result will determine the need for further psychosocial interventions; and in those cases, Diagnostic and Statistical Manual of Mental Disorders (DSM) diagnosis should be determined and documented. The evaluation should also include examination of both psychological comorbidities and psychological risk factors that are empirically associated with poor outcome and/or delayed recovery. An individual with a Ph.D., Psy.D, or psychiatric M.D./D.O. credentials should perform initial evaluations, which are generally completed within one to two hours. A professional fluent in the primary language of the patient is preferred. When such a provider is not available, services of a professional language interpreter should be provided.

iv. Frequency. One-time visit for the clinical interview. If psychometric testing is indicated as a part of the initial evaluation, time for such testing should not exceed an additional two hours of professional time.

(a). Tests of Psychological Functioning

(i). Psychometric testing is a valuable component of a consultation to assist the physician in making a more effective treatment plan. Psychometric testing is useful in the assessment of mental conditions, pain conditions, cognitive functioning, treatment planning, vocational planning and evaluation of treatment effectiveness. There is no general agreement as to which standardized psychometric tests should be specifically recommended for psychological evaluations of chronic pain conditions. It is appropriate for the mental health provider to use their discretion and administer selective psychometric tests within their expertise and within standards of care in the community. Some of these tests are available in Spanish and other languages, and many are written at a 6th grade reading level.

4. Special Tests. Tests are generally well-accepted tests and are performed as part of a skilled assessment of the patients' capacity to return to work, strength capacity, and or physical work demands classifications and tolerance. Tests include Computer-Enhanced Evaluations, Functional Capacity Evaluation (FCE), Jobsite Evaluation, Vocational Assessment, and Work Tolerance Screening. Refer to the Chronic Pain Medical Treatment Guidelines for detailed information and frequency of each special testing procedure.

La. Admin. Code tit. 40, § I-2127

Promulgated by the Louisiana Workforce Commission, Office of Workers Compensation Administration, LR 37:1719 (June 2011), Amended LR 46254 (2/1/2020).

AUTHORITY NOTE: Promulgated in accordance with R.S. 23:1203.1.