On Appeal from Superior Court, Bennington Unit, Civil Division John P. Wesley, J.
J. Norman O’Connor, Jr., North Adams, Massachusetts, and Donovan & O’Connor, LLP, Bennington, for Plaintiff-Appellant.
Jeffrey W. Spencer of Law Office of Jeffrey W. Spencer, CPCU, Essex Junction, for Defendant-Appellee.
PRESENT: Reiber, C.J., Dooley, Skoglund and Robinson, JJ., and Eaton, Supr. J., Specially Assigned.
¶ 1. The central question in this case is whether the workers’ compensation laws preclude an impairment rating and associated award of permanent partial disability (PPD) benefits to an injured worker on account of impairment associated with a condition known as Complex Regional Pain Syndrome (CRPS) where a claimant is not diagnosed with CRPS under the criteria listed in Chapter 16 of the American Medical Association Guides to the Evaluation of Permanent Impairment, Fifth Edition (AMA Guides, or Guides), but where a qualified expert confirms the existence of the condition pursuant to other legally admissible standards sufficient to meet a reasonable medical certainty. The Commissioner of the Department of Labor (DOL) and the trial court both concluded that 21 V.S.A. § 648(b) denies the Commissioner discretion to assign an impairment rating and thus award PPD benefits for impairment associated with CRPS where the CRPS diagnosis does not meet the diagnostic standards in Chapter 16 of the AMA Guides. We reverse.
¶ 2. In 2006, in the course of his employment as a master plumber, claimant tore the rotator cuff in his right shoulder when he slipped and fell down a flight of stairs. In January 2007, claimant had surgery to repair the rotator cuff, after which he began physical therapy. His recovery was complicated by adhesive capsulitis—inflammation of the shoulder joint causing stiffness and chronic pain—as well as symptoms of CRPS. In April 2007, claimant underwent shoulder manipulation under anesthesia to treat the adhesive capsulitis; the procedure resulted in increased shoulder motion, but claimant’s CRPS symptoms persisted.
¶ 3. Dr. Robert Giering, a psychiatrist and pain management specialist, affirmed the CRPS diagnosis, relying on the diagnostic criteria from the International Association for the Study of Pain (IASP), confirmed that the condition was causally related to claimant’s work accident, and treated claimant for the CRPS.
¶ 4. Employer retained its own medical expert, Dr. Kuhrt Wieneke. Dr. Wieneke first saw claimant in March 2008. At that time, Dr. Wieneke confirmed the diagnosis of CRPS and concluded that claimant had not yet reached a medical end. Employer did not challenge the award of temporary disability and medical benefits to claimant on account of the CRPS.
¶ 5. In June 2008, Dr. Giering determined that claimant had reached an end medical result and referred claimant to Dr. Lefkoe for an impairment rating. In October 2008, Dr. Lefkoe issued a sixteen-page report in which he accepted Dr. Giering’s CRPS diagnosis and assigned a forty-six percent whole person impairment rating calculated using the rating process for CRPS in the AMA Guides.
¶ 6. Dr. Wieneke saw claimant again in May 2009 to assess claimant’s permanent impairment on behalf of employer. Using the Guides, he concluded that claimant’s CRPS had resolved and assigned a three percent whole person rating to claimant’s shoulder injury on account of range-of-motion limitations and generalized pain. But because he concluded that claimant did not satisfy the diagnostic criteria for CRPS listed in Chapter 16 of the AMA Guides, Dr. Wieneke did not attribute any impairment for deficits or symptoms associated with CRPS.
¶ 7. After a contested hearing on the question of claimant’s impairment rating, the DOL Commissioner issued findings and conclusions. The Commissioner explained that CRPS is a condition of the sympathetic nervous system characterized by burning pain throughout the affected limb. The Commissioner described the four categories of signs and symptoms of CRPS: (1) pain disproportionate to what would be expected from the inciting injury and/or pain in response to a light touch that is not normally painful; (2) changes in skin color and/or temperature in the affected limb; (3) edema, swelling and/or sweating in the affected limb; and (4) motor changes, such as decreased range of motion and or motor dysfunction, and trophic changes involving abnormal nail and/or hair growth.
¶ 8. The Commissioner also explained that the AMA Guides and the IASP rely on similar objective signs to support a CRPS diagnosis. However, Chapter 16 of the AMA Guides requires a greater number of those signs to support a CRPS diagnosis, and calls for consideration only of observed signs, as opposed to reported symptoms. For that reason, the AMA Guides’ diagnostic criteria are more stringent than those of the IASP. 
¶ 9. The Commissioner had no doubt that under the IASP’s diagnostic criteria claimant was properly diagnosed with CRPS, but concluded that the record did not support the CRPS diagnosis under the AMA Guides’ diagnostic rubric. As a result, the Commissioner concluded: “I am compelled to reject Dr. Lefkoe’s opinion—not because it is unpersuasive, but because under the particular circumstances of this case the statute requires it.” The Commissioner found that Dr. Lefkoe used the appropriate mechanism under the AMA Guides for rating impairment associated with CRPS, but concluded that unless CRPS is diagnosed in accordance with the criteria outlined in Chapter 16 of the AMA Guides, a claimant is not entitled to a rating for impairment associated with CRPS. Accordingly, the Commissioner assigned a three percent whole person impairment rating per Dr. Wieneke’s report.
¶ 10. Claimant appealed to the superior court which held a de novo bench trial on the question of claimant’s permanent impairment rating. In a thoughtful opinion, the court compared the competing expert medical opinions and found that Dr. Lefkoe’s evaluation was “more comprehensive and explained clearly the basis for his opinion, ” while “Dr. Wieneke was less thorough and less clear when articulating how he arrived at his permanency rating, at one point contradicting himself while testifying.” The court also concluded that Dr. Lefkoe spent considerably more time evaluating claimant than Dr. Wieneke, and drafted a significantly longer and more thorough report.
¶ 11. Nonetheless, like the Commissioner, the court concluded that it was bound to reject Dr. Lefkoe’s rating for impairment associated with CRPS because 21 V.S.A. § 648(b) provides, “Any determination of the existence and degree of permanent partial impairment shall be made only in accordance with the whole person determination as set out in the fifth edition of the [AMA Guides].” The court found that the AMA Guides Chapter 16 criteria “controls both the diagnosis of impairments and the corresponding computation of the impairment rating, ” and that as a matter of law to qualify for a permanent impairment rating “a condition must be diagnosed in accordance with the AMA Guides 5th criteria.” From this, the court concluded that “as a matter of law, in order to qualify for a permanent impairment rating, a condition must be diagnosed in accordance with the AMA Guides 5th criteria.”  Although the court rejected Dr. Lefkoe’s rating of claimant’s impairment associated with CRPS, it did adopt Dr. Lefkoe’s findings concerning impairment associated with claimant’s loss of range of motion, and it increased claimant’s impairment rating to six percent whole person.
¶ 12. The sole question on appeal is whether 21 V.S.A. § 648(b) requires a factfinder to disallow any permanent impairment rating associated with CRPS where the diagnosis does not comport with the diagnostic standards in Chapter 16 of the AMA Guides.
¶ 13. A brief review of relevant aspects of Vermont’s workers’ compensation law and the AMA Guides is helpful. Vermont’s workers’ compensation law requires employers to provide specified benefits on a no-fault basis to workers who suffer “a personal injury by accident arising out of and in the course of employment.” 21 V.S.A. § 618. Among the benefits potentially available to an injured worker are medical benefits, id. § 640, temporary total or partial disability benefits, id. §§ 642, 646, vocational rehabilitation benefits, id. § 641, and permanent partial or permanent total disability benefits, id. §§ 644, 648.
¶ 14. The award of temporary disability benefits is based on an individual’s incapacity for work. Bishop v. Town of Barre, 140 Vt. 564, 571, 442 A.2d 50, 53 (1982). Permanent partial disability benefits are awarded based on an assessment of an individual’s “impairment, ” without direct consideration of the impact of that impairment on an individual’s capacity to work. Id.; see also 21 V.S.A. § 648. Neither the statute nor the DOL’s rules define “impairment, ” but the Vermont Legislature has directed that permanent impairment be assessed using the AMA Guides: “ Any determination of the existence and degree of permanent partial impairment shall be made only in accordance with the whole person determinations as set out in the fifth edition of the American Medical Association Guides to the Evaluation of Permanent Impairment.” 21 V.S.A. § 648(b).  The statute further provides that the Commissioner shall adopt a supplementary schedule for rating injuries not rated by the operative guidelines. The DOL, by rule, has provided that impairments for injuries not rated by the AMA Guides “shall be in proportion to the compensation paid for similar injuries rated by the Guides.” Workers’ Compensation Rules § 11.2500, 3 Code of Vt. Rules 24 010 003-8, available at
¶ 15. Significantly, although the concept of a “diagnosis” may be helpful in describing or labeling an injury, nothing in Vermont’s workers’ compensation scheme predicates a claimant’s entitlement to benefits on the existence of a particular diagnosis. The threshold trigger for benefits is an “injury”—defined in the case of physical injuries as “any harmful... change in the body.” Workers’ Compensation Rules § 2.1240, 3 Code of Vt. Rules 24 010 003-2, available at
http://www.lexisnexis.com/hottopics/codeofvtrules. T he touchstone for PPD benefits is “impairment” as measured pursuant to the AMA Guides or determined by the Commissioner if the Guides do not rate a particular type of injury. The Guides define impairment as “a loss, loss of use, or derangement of any body part, organ system, or organ function.” AMA Guides at 2 (quotations omitted).
¶ 16. The AMA Guides to the Evaluation of Permanent Impairment were developed “in response to a public need for a standardized, objective approach to evaluating medical impairments.” Id. at 1. The AMA Guides are broken into chapters, each focusing on impairment rating methods for a different organ system or body part, and each authored by experts from the relevant specialties. Id.  The impairment rating methodologies vary considerably from chapter to chapter, depending on the body parts or organ systems involved. Some impairments can be rated pursuant to multiple chapters. Id. at 19. Although the diagnosis associated with an injury may point the examiner to the applicable impairment rating methodology or methodologies in a given case, “diagnosis” per se is not intrinsic to the identification or measurement of many impairments in the AMA Guides. See, e.g., id. at 450-79 (rating impairments in range of motion of various joints without reference to diagnosis of condition causing limitation in range of motion); id. at 118-120 (rating upper digestive tract impairment with reference to symptoms and signs of upper digestive tract disease or anatomic loss or alteration without regard to specific underlying diagnosis). But see id. at 231 (providing that impairment rating for diabetes mellitus varies depending on whether diabetes is Type 1 or Type 2).
¶ 17. The Guides provide two distinct methods for rating CRPS in an upper extremity—one in Chapter 13 relating to the central and peripheral nervous system, id. at 343-44, and another at section 16.5e of Chapter 16 relating to the upper extremities, id. at 482-83, 495-97. At issue in this case is the approach laid out in Chapter 16.  With respect to the diagnosis of CRPS, that chapter identifies eleven objective diagnostic criteria for CRPS and provides that the presence of eight or more of those factors supports a CRPS diagnosis. Id. at 496, Table 16-16. For the purposes of assigning an impairment rating, the Chapter further distinguishes between CRPS I, also known as reflex sympathetic dystrophy (RSD), and CRPS II, also known as causalgia. Id. at 495-96. The CRPS I rating methodology applies when neither the initiating causative factor nor the symptoms involve a specific peripheral nerve or structure, and the CRPS II methodology applies when a specific sensory or mixed nerve structure is involved. Although Chapter 16 lists criteria for identifying ...