OPINION
The opinion of the Court issued December 20, 2007 is withdrawn, and the following is the opinion of the Court.
Appellant, Fireman’s Fund Insurance Company (“Fireman’s Fund”), appeals the district court’s judgment in favor of workers’ compensation claimant, Weldon Weeks, the Appellee herein. Fireman’s Fund contends that the evidence relied upon by the district court regarding Ap-pellee’s impairment rating and date of maximum medical improvement is legally insufficient. For the following reasons, we reverse the judgment of the trial court and render judgment for Fireman’s Fund.
BACKGROUND
On August 20, 1999, Weeks, who was employed by WW Rogers Produce, suffered an on-the-job injury, when he fell from a forklift and injured his lower back. On August 25, Weeks visited Dr. Huntly Chapman regarding the injury. Dr. Chapman initially prescribed medicine and therapy for him, but Weeks continued to experience pain in his back. On June 13, 2001, Dr. Chapman performed a spinal fusion surgery on Weeks, fusing his L3-4 and L4-5 vertebrae. Following the surgery, Weeks continued to experience back pain.
On December 14, 2001, Weeks was examined by Dr. Donald Mauldin, who was selected by Fireman’s Fund. Dr. Mauldin reported that Weeks reached Maximum Medical Improvement (“MMI”) on December 14, 2001. According to Dr. Mauldin, Weeks had an impairment rating of 20 percent. At the request of Fireman’s Fund, Dr. Phillip Osborne conducted a peer review of Dr. Mauldin’s report. Dr. Osborne concurred with Dr. Mauldin’s impairment rating. Dr. Osborne concluded that “this rating follows The Guides 1 and I do not believe that you will be successful disputing it.”
The Division of Workers’ Compensation of the Texas Department of Insurance
2
Dr. Chapman disputed Dr. Singleton’s conclusions. On October 14, 2002, Dr. Chapman performed an evaluation on Weeks and concluded that Weeks’s MMI date was April 17, 2002, based on the 104-week limitation contained in the definition of MMI. See Tex. Lab.Code Ann. § 401.011(30)(B). Dr. Chapman also concluded that Weeks’s injury was properly categorized as DRE category V, due to the fact that Weeks had undergone spinal fusion surgery and because of the presence of radiculopathy. Based on this, Dr. Chapman assigned Weeks an impairment rating of 25 percent.
Dr. Singleton stood by his decision. He explained that, under the AMA Guides, it would be inappropriate to consider the presence of a spinal fusion alone in determining impairment. Dr. Singleton re-examined Weeks on April 21, 2004, and again rated him at 10 percent impairment, with an MMI date of January 28, 2002.
On March 25, 2004, the Division held a contested case hearing to ■ determine, among other things, the date of MMI and Weeks’s impairment rating. The hearing officer noted that “[t]he differences between Dr. Singleton’s certification and those of the other doctors are in the area of medical judgment. Specifically, Dr. Singleton did not use the multilevel fusion to place Claimant in a higher DRE category for loss of motion segment integrity, whereas the other doctors did.” The hearing officer concluded, in agreement with Dr. Singleton, that Weeks had an MMI date of January 28, 2002, and an impairment rating of 10 percent. 3 Weeks appealed this decision to the Division’s Appeals Panel, which did not issue a decision within the time permitted by the Texas Labor Code. The hearing officer’s decision therefore became the final decision of the Appeals Panel. See Tex. Lab.Code Ann. § 410.204(c).
Weeks then appealed to the 162nd District Court, which conducted a bench trial in November of 2005, to determine Weeks’s MMI date and impairment rating. The district court entered a final judgment on February 2, 2006, ruling that Weeks had an MMI date of April 17, 2002, and an impairment rating of 25 percent. Fireman’s Fund appeals the district court’s judgment, arguing that the evidence relied upon was legally insufficient, because the reports of Drs. Chapman, Mauldin, and
DISCUSSION
A. Standard of Review
The Division’s decision on issues involving compensability of the injury and eligibility for and the amount of income and death benefits is reviewed by the district court under a modified
de novo
review.
Texas Workers’ Compensation Comm’n v. Garcia,
When the trial court is the trier of fact, a legal sufficiency challenge to the trial court’s findings of fact is reviewed under the same standard that is applied in reviewing evidence supporting a jury’s answer.
Catalina v. Blasdel,
In reviewing a legal sufficiency challenge, we view the evidence in the light most favorable to the judgment, crediting favorable evidence if a reasonable juror could and disregarding contrary evidence, if a reasonable juror could not.
City of Keller,
B. Requirements for Impairment Ratings
The Texas Workers’ Compensation Act (the “Act”) authorizes four types of income benefits: (1) temporary income benefits; (2) impairment income benefits; (3) supplemental income benefits; and (4) lifetime income benefits.
See Garcia,
Section 408.124(a) of the Labor Code provides that “[a]n award of an impairment income benefit ... must be based on an impairment rating determined using the impairment rating guidelines described by this section.” Tex. Lab.Code Ann. § 408.124(a);
see
28 Tex. Admin. Code § 130.1(c)(2) (“A doctor who certifies that an injured employee has reached MMI shall assign an impairment rating for the current compensable injury using the rating criteria contained in the appropriate edition of the AMA Guides .... ”);
see also Garcia,
“The principal methodology found in the fourth edition of the
Guides
is its injury model, which uses objectively verifiable evidence to place patients into one of eight diagnosis-related estimate (DRE) categories.”
Lumbermens Mut.,
In order for a lumbosacral spine injury to be categorized as DRE category IV, the Guides requires that the claimant have suffered either a loss of motion segment integrity or a structural inclusion. Id. According to the Guides, “[l]oss of motion segment or structural integrity is defined as abnormal back-and-forth motion (translation) or abnormal angular motion of a motion segment with respect to an adjacent motion segment.” 5 A loss of motion segment integrity can be established with x-rays that show a translation of at least 5mm for one vertebra on another in the lumber spine or a difference in the angular motion of two adjacent motion segments greater than 11 degrees in response to spine flexion and extension. Id. at 872-73. Alternatively, the existence of a structural inclusion may justify a determination of DRE category IV. “The structural inclusions for the DRE TV category for the lumbosacral spine are: ‘(1) Greater than 50% compression of one vertebral body without residual neurologic compromise; [and] (2) multilevel spine segment structural compromise, as with fractures or dislocations, without residual neurologic motor compromise.’ ” Id. at 873.
Surgery is not a factor to be considered in determining impairment ratings under the Injury Model. As the Guides states, “[w]ith the Injury Model, surgery to treat an impairment does not modify the original impairment estimate, which remains the same in spite of any changes in signs or symptoms that may follow the surgery and irrespective of whether the patient has a favorable or unfavorable response to treatment.”
In
Lumbermens Mut,
the Austin Court of Appeals affirmed a district court declaration that certain Division advisories regarding impairment rating methods for spinal fusion recipients constituted an invalid attempt by the Division at ad hoc rulemaking and that the application of the advisories was an ultra vires act by the Division.
Lumbermens Mut.,
[U]nder the injury model of the Guides, doctors may not use their medical judgment or experience to take surgery or the effect of surgery into account when assigning impairment ratings. By issuing and applying advisories that allow doctors to do just that, the Division has acted outside its statutory authority because the fourth edition of the Guides is the only permissible source for determining impairment ratings within the Texas workers’ compensation system.
Id.
at 876 (citing Tex. Lab.Code Ann. § 408.124; 28 Tex. Admin. Code § 130.1(c); and
Garcia,
C. Evidence of Weeks’s Impairment Rating
Although the district court did not issue findings of fact and conclusions of law, we construe the court as having adopted Dr. Chapman’s report as the basis for its judgment. 8 Weeks does not dispute that Dr. Chapman relied upon the fact that he had undergone spinal fusion in determining his impairment rating. Dr. Chapman performed a medical evaluation on Weeks on October 14, 2002, and testified that he believed that he followed the injury model in doing so. Dr. Chapman placed Weeks’s injury into DRE category V and assigned a 25 percent impairment rating. Dr. Chapman explained that his determination was “based upon the fact that this gentleman has had a spinal fusion and therefore has had a controlled fracture and therefore fits in the multilevel spinal segment structural compromise definition of Motion Segment Integrity Loss.”
Dr. Chapman’s reliance on Weeks’s surgery in determining his impairment rating is also evident in his prior correspondence to the Division. In a letter dated July 8, 2002, Dr. Chapman wrote that Weeks’s spinal fusion involved a controlled fracture and that “[therefore a spine fusion ... is Loss of Motion Segment Integrity.” According to- Dr. Chapman, this put Weeks’s injury into a DRE category IV, which, coupled with his radiculopathy, resulted in DRE category V and a 25 percent impairment rating. In a September 25, 2002, letter to the Division, Dr. Chapman wrote that “structural inclusion includes fractures or dislocations and since spinal fusions are controlled fractures ... it is an absolute fact that spinal fusions are controlled fractures and therefore anyone undergoing a spinal fusion has had a fracture.... ” In the same letter, Dr. Chapman acknowledged that his conclusion was based on the “more recent Guides” and not on the “State of Texas mandated Guides.”
Finally, in his deposition testimony, which was read into evidence at trial, Dr. Chapman answered affirmatively when asked whether he found loss of motion segment integrity based upon the fact that Weeks had undergone surgery. In addition, Dr. Chapman answered affirmatively when asked whether the reason that he had put Weeks into DRE category V, rather than DRE category III, rested on the fact that Weeks had a spinal fusion. Accordingly, Dr. Chapman’s impairment rating was based upon a factor not permitted by the Guides. The evidence as to Dr. Chapman’s impairment rating was therefore legally insufficient to support the judgment. We sustain Issue One.
Fireman’s Fund also appeals the district court’s judgment that Weeks reached maximum medical improvement on April 17, 2002, which is the date reported by Dr. Chapman. Fireman’s Fund argues that Dr. Singleton’s impairment rating was the only valid impairment rating introduced at trial, so the corresponding MMI date was the only valid MMI date in evidence. Fireman’s Fund relies on that portion of the Texas Administrative Code which provides that “[a]ssignment of an impairment rating for the current compen-sable injury shall be based on the injured employee’s condition as of the MMI date considering the medical record and the certifying examination.” 28 Tex. Admin. Code § 130.1(c)(3).
While the Labor Code requires that the trial court adopt a specific impairment rating, there is no similar requirement with regard to the MMI date of a claimant.
See
Tex. Lab.Code Ann. § 410.306. However, the Supreme Court has noted that “[a]ny dispute that challenges an impairment rating’s finality necessarily implicates the date of maximum medical improvement and the amount paid as temporary income benefits.”
Rodriguez v. Service Lloyds Ins. Co.,
[W]e have never held that MMI and IR can never be individually considered and decided. IR can be decided separately from MMI, for example, when MMI is agreed to by the parties or when, as in this case, statutory MMI has been reached. In such cases, it is essential only that MMI be reached before an IR is assigned.
Appeal No. 931125,
We therefore reverse the judgment of the trial court and render judgment affirming the decision of the Division.
Notes
. The American Medical Association publication entitled "Guides to the Evaluation of Permanent Impairment” is popularly referred to as the "AMA Guides” or simply the "Guides." Cf. 28 Tex. Admin. Code § 130.1 (c)(2)(B)(i) (Tex. Dep't of Ins., Div. of Workers’ Comp., Impairment and Supplemental Income Benefits).
. The Texas Workers' Compensation Commission was the agency formerly charged with administration of the Texas Workers' Com
. The Division’s hearing officer also determined that the Division’s appointment of Dr. Lawrence Reid as a second designated doctor was improper. Weeks stipulated at trial that this decision was not at issue and that he was not challenging it. The district court’s final judgment recites that “Plaintiff waived the : issue of whether Dr. Lawrence Reid was properly appointed as a Designated Doctor.” Therefore, Dr. Reid’s report is not at issue in this appeal. Moreover, Dr. Reid’s report suffers from the same defect as that of Dr. Chapman's reports, discussed below.
. The date of maximum medical improvement may also be determined pursuant to Labor Code § 408.104(a), which provides for extensions in cases of spinal surgery. However, there is no evidence in the record that such an extension was sought or granted in this case.
. The Guides defines a motion segment of the spine as "two adjacent vertebrae, an interca-lated disk, and the vertebral facet joints.”
. In his decision on the contested case hearing, the hearing officer noted that it was not shown that each of the required preoperative x-rays of Weeks had been taken, nor is this clear from the record. However, the presence or absence of such x-rays does not alter the outcome of this appeal.
. Subsequent Appeals Panel decisions have overturned contested case hearing decisions in which the impairment rating adopted by the hearing officer was based on the application of the Advisories.
See
Appeal No. 071186,
. The trier of fact in the review of a Division decision is required to adopt the impairment rating of one of the physicians in the case,
Garcia,
