                  IN THE SUPREME COURT OF THE STATE OF IDAHO

                                        Docket No. 42782

ROY GREEN,                                          )
                                                    )
      Claimant-Respondent,                          )
                                                    )        Boise, December 2015 Term
v.                                                  )
                                                    )        2016 Opinion No. 48
ROY GREEN, dba ST. JOES SALVAGE
LOGGING, Employer, and TRAVELERS                    )
INDEMNITY COMPANY, Surety,                          )        Filed: April 26, 2016
                                                    )
      Defendants-Respondents,                       )        Stephen Kenyon, Clerk
                                                    )
and                                                 )
                                                    )
STATE OF IDAHO, INDUSTRIAL                          )
SPECIAL INDEMNITY FUND,                             )
                                                    )
      Defendant-Appellant.                          )

         Appeal from the Industrial Commission of the State of Idaho.

         The decision of the Industrial Commission is affirmed.

         Jones, Brower & Callery, LLP, Lewiston and Mallea Law Offices, Meridian, for
         appellant. Kenneth Mallea argued.

         Bowen & Bailey, LLP, Boise, for respondents St. Joes Salvage Logging and
         Travelers Indemnity Company. William Scott Wigle argued.

         Starr Kelso Law Offices, Coeur d’Alene, for respondent Green.
              _______________________________________________

HORTON, Justice.
         The Industrial Special Indemnity Fund (ISIF) appeals a decision of the Industrial
Commission in which the Commission concluded that ISIF must pay a portion of Roy Green’s
disability benefits because Green had a pre-existing condition. We affirm.
                    I.       FACTUAL AND PROCEDURAL BACKGROUND
         On July 3, 2006, Green was logging alone when a tree that he estimates weighed 1700
pounds fell on him, striking him on his hardhat (the 2006 Accident). The accident occurred after


                                                1
another tree that he had just felled knocked the culpable tree loose. Green avoided being crushed
only because of the presence of a nearby stump. When Green came to, he found that his legs
were tingling, he had little sensation and difficulty walking. Green managed to drive to St.
Maries to seek medical treatment.
       After receiving treatment from various physicians and completing an Independent
Medical Evaluation (IME), Green was referred to neurosurgeon Dr. Bret Dirks. Dr. Dirks
diagnosed Green with a lower back injury that was directly related to the 2006 Accident. Dr.
Dirks recommended surgery, and on February 21, 2007, Green underwent a bi-level lumbar
fusion with decompression surgery from L3 to L5 (the Lumbar Fusion).
       Following the surgery, Green expressed concern about “right-sided neck pain that goes
into the right arm and makes it feel like jelly.” MRI images of Green’s cervical spine taken on
July 11, 2006, and May 23, 2007, showed, among other things, a bulging disk at C5–6. Dr. Dirks
recommended an anterior cervical discectomy and fusion at C5–6 with plating and cadaver bone.
Dr. Dirks attributed the need for this surgery to the 2006 Accident. On July 16, 2007, Green
underwent cervical fusion surgery at C5–6 (the Cervical Fusion).
       On October 30, 2006, Green filed a complaint against St. Joes Salvage Logging
(Employer) and Travelers Indemnity Company (Surety). Two years later, on November 6, 2008,
Employer/Surety filed a complaint against ISIF. A hearing on the case began in August of 2012
before a worker’s compensation referee assigned by the Commission. After the referee retired in
April of 2013, the case was reassigned to the Commission.
       The Commission issued a 115 page decision on January 29, 2014. The decision detailed
Green’s complicated medical, legal, and occupational history. The Commission found that Green
had a 20% whole person permanent partial impairment (PPI) due to the Lumbar Fusion and a
25% PPI due to the Cervical Fusion resulting from the 2006 Accident. The Commission also
determined Green was totally and permanently disabled under the odd-lot doctrine.
       The Commission also considered whether Green had pre-existing injuries that subjected
ISIF to liability. Employer/Surety’s complaint against ISIF alleged Green had the following pre-
existing injuries: (1) a T12–L1 fusion (the Thoracic Fusion), (2) a separation of the right
shoulder, (3) bilateral carpal tunnel syndrome, and (4) multi-level cervical and lumbar disc
disease and spinal degeneration. The Commission determined that Employer/Surety had failed to
establish ISIF liability for the pre-existing conditions, with the exception of the Thoracic Fusion.


                                                 2
       Green had the Thoracic Fusion surgery in January of 2003. The injury which precipitated
the surgery occurred while Green was cutting a limb off a tree. The Commission concluded that
Green was “likely entitled to an impairment rating referable to the T12-L1 fusion and residuals.
However, the record altogether fails to establish what that impairment might be.” The
Commission determined:
       The Commission recognizes its authority, as discussed in Hartman v. Double L
       Manufacturing, 141 Idaho 456, 111 P.3d 141 (2005), to request evidence on the
       issue of Claimant’s pre-existing thoracic spine impairment, yet we are reluctant to
       do so when the parties, represented by experienced counsel, had ample
       opportunity to marshal such evidence prior to hearing. The issue was clearly
       noticed and the parties are well aware of the elements required to prove and
       calculate ISIF liability. However, we believe the facts of this case mandate an
       assessment of the extent and degree of Claimant’s pre-existing thoracic
       impairment considering the overwhelming proof that Claimant suffered from a
       pre-existing impairment which would impact Employer/Surety and ISIF’s
       liability. Justice demands that we request that the parties present additional
       evidence of Claimant’s pre-existing thoracic spine condition. As in Hartman we
       deem it necessary to retain jurisdiction of this matter in order to allow the parties
       to adduce additional evidence on the following question:
       (1) What is the appropriate impairment rating for Claimant’s pre-existing thoracic
           spine condition?
       Thereafter, the parties submitted additional evidence, with Employer/Surety arguing the
Thoracic Fusion resulted in a 20% PPI and ISIF arguing the Thoracic Fusion resulted in a 16%
PPI. On November 26, 2014, the Commission issued its Order on ISIF Liability. The
Commission found Employer/Surety’s PPI rating of 20% to be more credible. Thus, the
Commission determined Green’s impairments totaled 65% (20% for the Lumbar Fusion, 25% for
the Cervical Fusion, and 20% for the pre-existing Thoracic Fusion). Using the formula from
Carey v. Clearwater Cnty. Rd. Dep’t, 107 Idaho 109, 686 P.2d 54 (1984), the Commission
determined Employer/Surety was responsible for 69.23% of Green’s physical impairment.
       Further, the Commission declined to reconsider issues that ISIF had tried to raise relating
to its January 29, 2014, decision, including a challenge to the Commission’s decision to retain
jurisdiction. The Commission held that it could not reconsider these issues because neither party
had filed a timely motion for reconsideration under Idaho Code section 72-718.
       On December 23, 2014, ISIF timely appealed from the November 26, 2014 order.




                                                3
                                       II.      STANDARD OF REVIEW
         “When reviewing a decision by the Industrial Commission, this Court exercises free
review over the Commission’s conclusions of law, but will not disturb the Commission’s factual
findings if they are supported by substantial and competent evidence.” Knowlton v. Wood River
Med. Ctr., 151 Idaho 135, 140, 254 P.3d 36, 41 (2011) (citing I.C. § 72-732). “Substantial and
competent evidence is relevant evidence that a reasonable mind might accept to support a
conclusion.” Uhl v. Ballard Med. Products, Inc., 138 Idaho 653, 657, 67 P.3d 1265, 1269 (2003).
“The interpretation of a statute is a question of law over which this Court exercises free review.”
Williams v. Blue Cross of Idaho, 151 Idaho 515, 521, 260 P.3d 1186, 1192 (2011).
         The Commission’s decision to retain jurisdiction to allow parties to submit additional
evidence is reviewed for an abuse of discretion.1 “In determining whether the Commission has
abused its discretion, this Court employs a three-part test: (1) whether the Commission correctly
perceived the issue as one of discretion, (2) whether it acted within the outer boundaries of its
discretion and consistently with the legal standards applicable to the specific choices available to
it, and (3) whether it reached its decision by an exercise of reason.” Super Grade, Inc. v. Idaho
Dep’t of Commerce & Labor, 144 Idaho 386, 390, 162 P.3d 765, 769 (2007).
                                                 III.     ANALYSIS
         The issues presented in this appeal are whether: (1) ISIF timely appealed, (2) the
Commission abused its discretion by retaining jurisdiction, (3) the Commission erred in
determining the elements of ISIF liability were established, and (4) this Court may address
Employer/Surety’s claim that the Commission erred by not including a 5% pre-existing lumbar
impairment in addition to the 20% impairment attributed to the Thoracic Fusion. We address
these issues in turn.
A. ISIF timely appealed.


1
  This is the first time we have identified the applicable standard of review in this particular circumstance. We find
an abuse of discretion standard to be applicable for two reasons. First, the applicable statute, Idaho Code section 72-
714(3), provides: “The commission, or member thereof, or a hearing officer, referee or examiner, to whom the
matter has been assigned, shall make such inquiries and investigations as may be deemed necessary.” The use of the
word “may” demonstrates discretion. Marcia T. Turner, L.L.C. v. City of Twin Falls, 144 Idaho 203, 211, 159 P.3d
840, 848 (2007). Second, we have applied the standard in analogous situations. See Flowers v. Shenango
Screenprinting, Inc., 150 Idaho 295, 297, 246 P.3d 668, 670 (2010) (using a discretionary review standard to review
the Commission’s decision to not allow a supplemental hearing in the unemployment benefits context applicable
under Idaho Code section 72-1368(7)); Ball v. Daw Forest Products Co., 136 Idaho 155, 162, 30 P.3d 933, 940
(2001) (reviewing the Commission’s decision not to retain jurisdiction when a claimant’s condition was unstable for
an abuse of discretion).

                                                          4
         Employer/Surety contends ISIF did not timely appeal from the Commission’s January 29,
2014, decision that established ISIF’s liability for the Thoracic Fusion. Employer/Surety
contends that ISIF’s appeal is timely only as it relates to the Commission’s November 26, 2014,
decision that determined Green’s Thoracic Fusion resulted in a 20% PPI. Thus, Employer/Surety
maintains that ISIF may appeal the amount of impairment for the Thoracic Fusion but not its
liability.
         “[W]henever the Commission explicitly retains jurisdiction over a matter, that act by its
very nature infers that there is neither a final determination of the case nor a final permanent
award to the employee.” Reynolds v. Browning Ferris Indus., 113 Idaho 965, 969, 751 P.2d 113,
117 (1988). Here, the Commission explicitly retained jurisdiction, demonstrating that a final
determination had not been made. The final decision determining the parties’ rights was not
entered until November 26, 2014. ISIF’s notice of appeal was filed on December 23, 2014. We
hold that ISIF timely appealed.2
B. The Commission did not abuse its discretion when it retained jurisdiction to conduct a
   supplemental hearing.
         In its January 29, 2014, decision the Commission concluded that Green was “likely
entitled to an impairment rating . . . . However, the record altogether fails to establish what that
impairment might be.” The Commission retained jurisdiction so that the parties could present
additional evidence at a supplemental hearing so that it might determine the appropriate
impairment rating for Green’s pre-existing thoracic spine condition.




2
  We wish to note the apparent divergence between this Court and the Commission’s understanding of the operation
of Idaho Code section 72-718. The Commission expressed concern about a perceived discrepancy between a
sentence in a recent decision from this Court and the statute. In Vawter v. United Parcel Serv., Inc., 155 Idaho 903,
913, 318 P.3d 893, 903 (2014), this Court characterized a Commission order as “an interlocutory order that was
subject to modification until such time as a final, appealable order was entered.” The Commission appears to
believe this statement is at odds with Idaho Code section 72-718, which provides that a “decision of the commission,
in the absence of fraud, shall be final and conclusive as to all matters adjudicated,” subject to the parties’ right to
seek reconsideration within twenty days. The Commission stated: “It is difficult to square Vawter with the
unambiguous provisions of Idaho Code § 72-718.”
  The Commission appears to have adopted the position that parties may not seek reconsideration of interlocutory
rulings more than twenty days after they are made. The view we expressed in Vawter is based upon the final
sentence of Idaho Code section 72-718, which provides that “[f]inal decisions may be appealed to the Supreme
Court as provided by section 72-724, Idaho Code.” Our view is that a decision is not final, and thus appealable, until
all issues are resolved between all parties. Thus, in order to permit appeals of certain interlocutory decisions of the
Commission, we have adopted I.A.R. 11(d)(2), authorizing expedited appeals from compensability determinations.
The statement in Vawter to which the Commission has appeared to take exception is simply corollary to our view of
what constitutes a final decision.

                                                          5
       ISIF contends the Commission abused its discretion in its sua sponte decision to retain
jurisdiction and instead should have held that Employer/Surety failed to establish ISIF liability
because they did not meet their burden of providing evidence upon which an impairment rating
determination could be made. Employer/Surety responds that this Court has frequently upheld
the Commission’s decision to allow the submission of additional evidence.
       Idaho Code section 72-714(3) provides: “The commission, or member thereof, or a
hearing officer, referee or examiner, to whom the matter has been assigned, shall make such
inquiries and investigations as may be deemed necessary.” “This Court has interpreted this
statute as permitting the Commission to demand additional evidence if it finds that satisfactory
evidence on a question of material fact is lacking.” Mazzone v. Texas Roadhouse, Inc., 154 Idaho
750, 759, 302 P.3d 718, 727 (2013).
       “Since the inception of Idaho’s Workers’ Compensation Act, Industrial Commission
proceedings have been informal and designed for simplicity; the primary purpose of these
proceedings being the attainment of justice in each individual case.” Hartman v. Double L Mfg.,
141 Idaho 456, 458, 111 P.3d 141, 143 (2005) (quoting Hagler v. Micron Technology, Inc., 118
Idaho 596, 599, 798 P.2d 55, 58 (1990)). “[T]he Commission has historically been imbued with
certain powers that specifically enable it to simplify proceedings and enhance the likelihood of
equitable and just results.” Id. (alteration original) (quoting Hagler, 118 Idaho at 599, 798 P.2d at
58). One such power is:
       When a claimant has failed or overlooked submitting evidence to establish the
       amount of compensation to which he is entitled, and there is no question but that
       he is entitled to compensation, then it is the duty of the Board to call attention to
       such failure and see to it that whatever evidence is available to establish such fact
       is presented, and then make the necessary findings of fact.
Id. (quoting Watkins v. Cavanagh, 61 Idaho 720, 722, 107 P.2d 155, 157 (1940)).
       The Commission cited Hartman for its authority to retain jurisdiction to conduct an
additional hearing. In Hartman, the Commission determined a claimant was totally and
permanently disabled but it could not determine the extent of ISIF liability from the record.
Hartman, 141 Idaho at 457, 111 P.3d at 142. “Because the Industrial Commission could not
establish from the record the extent of ISIF’s liability, it retained jurisdiction over the issue to
enable the parties to resolve the matter or present additional evidence for consideration.” Id.
Although the appeal was resolved on procedural grounds, we also discussed the Commission’s


                                                 6
authority to retain jurisdiction and took the occasion to “remind” the ISIF that the Commission
“[c]learly” had authority to request additional evidence on an issue. Id.
       The Commission perceived the issue as one of discretion, as reflected by its statement
that “[t]he Commission recognizes its authority” to conduct an additional hearing in the interests
of justice. The Commission acted within the bounds of its discretion and consistently with the
applicable legal standard that we recognized in Hartman. The Commission reached its decision
through an exercise of reason, recognizing the “overwhelming proof” that the Thoracic Fusion
was a pre-existing condition as to which the parties had not provided adequate evidence to
establish an impairment rating. The Commission determined that the interests of justice required
that it receive additional evidence. For these reasons, we find no abuse of discretion.
        ISIF contends that this appeal presents a situation similar to one in which we reversed
the decision of the Commission. In Deon v. H & J, Inc., 157 Idaho 665, 667, 339 P.3d 550, 552
(2014), this Court considered whether the Commission erred when it sua sponte invited the
parties to submit briefing as to the effect an ISIF settlement should have on an employer and
surety’s liability despite the fact that those parties had failed to raise the defense on their own
initiative. Id. This Court reversed, reasoning that “this Court takes a dim view of fact-finding
tribunals raising defenses or theories sua sponte. Theories and defenses should be determined by
the parties, not the tribunal” and that “a party is bound by the theory upon which it tries its case.”
Id. at 671, 339 P.3d at 556. The present case is different. Although the Commission ordered the
parties to present additional evidence relating to an appropriate impairment rating for the
Thoracic Fusion, it did not raise a new theory or defense. Thus, our holding in Deon is
inapplicable.
       ISIF also argues that the Commission erred by applying equitable concepts in its decision
to retain jurisdiction. “[T]he Commission derives its authority solely from statutory law and does
not have the ability to operate in the equitable realm.” Id. at 669 n.2, 339 P.3d at 554 n.2. Here,
the Commission operated under its statutory authority to conduct an additional hearing when
additional inquiries are deemed necessary. See Hartman, 141 Idaho at 458, 111 P.3d at 143
(citing I.C. § 72-714(3)).
       ISIF contends that retained jurisdiction is not available to relieve a surety from its failure
to present evidence on an issue noticed for a hearing; rather, ISIF argues, retained jurisdiction is
only available for the benefit of claimants. We disagree. Although ISIF reviews a series of cases


                                                  7
involving retained jurisdiction for the benefit of a claimant who has not failed to present
sufficient evidence, ISIF fails to identify a decision wherein we have held that retained
jurisdiction is only available to claimants. As we have previously noted, Commission
proceedings are informal and designed for simplicity in order to attain justice in individual cases.
Hartman, 141 Idaho at 458, 111 P.3d at 143. “The purpose of establishing ISIF was to relieve an
employer of the burden of paying for total permanent disability compensation to an employee
rendered totally and permanently disabled because of a pre-existing handicap coupled with a
subsequent industrial injury.” Wernecke v. St. Maries Joint Sch. Dist. No. 401, 147 Idaho 277,
285, 207 P.3d 1008, 1016 (2009). “The goal was to encourage employers to hire handicapped
people by reducing the employer’s obligation to pay for industrial accidents in the amount it
would pay to an employee who had not been previously handicapped.” Id. Allowing employers
and sureties the opportunity to present evidence at a supplemental hearing when there is an
obvious pre-existing condition is consistent with these policies.
         For the foregoing reasons, we conclude that the Commission did not abuse its discretion
when it retained jurisdiction to conduct a supplemental hearing.
C. ISIF liability under Idaho Code section 72-332.
         “ISIF liability is governed by Idaho Code section 72-332(1).” Corgatelli v. Steel W., Inc.,
157 Idaho 287, 293, 335 P.3d 1150, 1156 (2014). Idaho Code section 72-332 provides:
                 (1) If an employee who has a permanent physical impairment from any
         cause or origin, incurs a subsequent disability by an injury or occupational disease
         arising out of and in the course of his employment, and by reason of the combined
         effects of both the pre-existing impairment and the subsequent injury or
         occupational disease or by reason of the aggravation and acceleration of the pre-
         existing impairment suffers total and permanent disability, the employer and
         surety shall be liable for payment of compensation benefits only for the disability
         caused by the injury or occupational disease, including scheduled and
         unscheduled permanent disabilities, and the injured employee shall be
         compensated for the remainder of his income benefits out of the industrial special
         indemnity account.
                (2) “Permanent physical impairment” is as defined in section 72-422,
         Idaho Code,[3] provided, however, as used in this section such impairment must be
         a permanent condition, whether congenital or due to injury or disease, of such
         seriousness as to constitute a hindrance or obstacle to obtaining employment or to
3
 “ ‘Permanent impairment’ is any anatomic or functional abnormality or loss after maximal medical rehabilitation
has been achieved and which abnormality or loss, medically, is considered stable or nonprogressive at the time of
evaluation. Permanent impairment is a basic consideration in the evaluation of permanent disability, and is a
contributing factor to, but not necessarily an indication of, the entire extent of permanent disability.” I.C. § 72-422.

                                                           8
       obtaining re-employment if the claimant should become employed. This shall be
       interpreted subjectively as to the particular employee involved, however, the mere
       fact that a claimant is employed at the time of the subsequent injury shall not
       create a presumption that the pre-existing permanent physical impairment was not
       of such seriousness as to constitute such hindrance or obstacle to obtaining
       employment.
I.C. § 72-332. “Under § 72–332(1), a party attempting to prove ISIF liability must show: (1)
‘there was a pre-existing impairment’; (2) ‘the impairment was manifest’; (3) ‘the impairment
was a subjective hindrance’; and (4) ‘the pre-existing impairment and the subsequent injury in
some way combine to result in total permanent disability.’ ” Corgatelli, 157 Idaho at 293, 335
P.3d at 1156 (internal quotations original) (quoting Vawter v. United Parcel Serv., Inc., 155
Idaho 903, 910, 318 P.3d 893, 900 (2014)). The party seeking to prove ISIF liability bears the
burden of proof on these elements. Id.
       ISIF advances two arguments in support of its claim that the Commission erred when it
found that ISIF was liable to pay a portion of Green’s benefits: (1) that determination of a
specific impairment rating is an element required to establish ISIF liability, and (2) that the
Commission’s finding that Green’s thoracic spine condition “combined with” the previous
industrial injuries to render Green totally and permanently disabled is not supported by
substantial and competent evidence.
   1. Employer/Surety was not required to establish an impairment rating as an element
      of its case prior to the Commission’s January 29, 2014, decision.
       In its decision of January 29, 2014, the Commission concluded that Green was “likely
entitled to an impairment rating . . . . However, the record altogether fails to establish what that
impairment might be.” Later, in its November 26, 2014, decision, the Commission found Green
had an impairment rating of 20% for the Thoracic Fusion. ISIF argues the Commission erred in
its original determination because an impairment rating is a required element for establishing
ISIF liability since it is needed to apportion liability under the formula established in Carey v.
Clearwater Cnty. Rd. Dep’t, 107 Idaho 109, 686 P.2d 54 (1984).
       Idaho Code section 72-424 provides: “ ‘Evaluation (rating) of permanent impairment’ is a
medical appraisal of the nature and extent of the injury or disease as it affects an injured
employee’s personal efficiency in the activities of daily living, such as self-care, communication,
normal living postures, ambulation, elevation, traveling, and nonspecialized activities of bodily
members.” “Evaluation of permanent impairment is conducted through a rating analysis,


                                                 9
expressed as a percentage.” Vawter, 155 Idaho at 909, 318 P.3d at 899 (discussing Idaho Code
section 72-422). ISIF is correct that an impairment rating must be established in order to
determine the extent of ISIF liability. See Carey, 107 Idaho at 118, 686 P.2d at 63 (providing a
formula that requires pre-existing and incident impairment ratings to apportion liability to ISIF in
odd-lot cases). However, ISIF does not direct us to statutory or decisional authority that
explicitly states that the Commission cannot require the presentation of additional evidence to
decide this issue. ISIF’s claim is closely related to our previous analysis as to whether the
Commission abused its discretion when conducting an additional hearing. As we have held, the
Commission possessed the authority to require additional evidence. See Hartman v. Double L
Mfg., 141 Idaho 456, 458, 111 P.3d 141, 143 (2005). We hold that Employer/Surety was not
required to establish an impairment rating as an element of its case prior to the Commission’s
January 29, 2014, decision.
    2. The Commission’s finding that Green’s Thoracic Fusion “combined with” the
       previous industrial injuries to render Green totally and permanently disabled is
       supported by substantial and competent evidence.
        ISIF challenges the Commission’s factual findings and legal analysis regarding the fourth
element of ISIF liability, the “combined with” element. ISIF argues the Commission did not
follow the applicable “but for,” causation standard. ISIF argues substantial and competent
evidence does not support the Commission’s conclusion that Green would not have been totally
and permanently disabled but for the Thoracic Fusion.
        “To satisfy the fourth requirement in Idaho Code section 72–332(1), ‘the “but for”
standard is the appropriate test to determine whether the total permanent disability is the result of
the combined effects of the pre-existing condition and the work-related injury.’ ”4 Corgatelli,
157 Idaho at 293, 335 P.3d at 1156 (quoting Garcia v. J.R. Simplot Co., 115 Idaho 966, 970, 772
P.2d 173, 177 (1989)). “The ‘but for’ test requires a showing by the party invoking liability that
the claimant would not have been totally and permanently disabled but for the preexisting
impairment.” Id.

4
  At oral argument, Employer/Surety questioned whether this Court should continue the application of the “but for”
test because the test deviates from the “combined effects” language in Idaho Code section 72-332(1). “[W]hen there
is controlling precedent on questions of Idaho law the rule of stare decisis dictates that we follow it, unless it is
manifestly wrong, unless it has proven over time to be unjust or unwise, or unless overruling it is necessary to
vindicate plain, obvious principles of law and remedy continued injustice.” Asbury Park, LLC v. Greenbriar Estate
Homeowners’ Ass’n, Inc., 152 Idaho 338, 343, 271 P.3d 1194, 1199 (2012) (quoting Greenough v. Farm Bureau
Mut. Ins. Co. of Idaho, 142 Idaho 589, 592, 130 P.3d 1127, 1130 (2006)). We are unwilling to take up
Employer/Surety’s argument because we do not have briefing from the parties on this issue.

                                                         10
           In the present case, the Commission employed the correct test. The Commission’s
decision began with a correct statement of the test—that “Employer/Surety bears the burden of
demonstrating that but for the pre-existing conditions, Claimant would not be totally and
permanently disabled following the work accident.” The Commission explicitly asked the proper
question, whether Green’s current total and permanent disability “obtains solely from the
combined effects of the work accident and Claimant’s pre-existing impairments.” The
Commission found the opinions from two experts— Dr. William Ganz and Dr. John McNulty—
to be particularly persuasive. In a report dated October 1, 2008, Dr. Ganz, the physician who
performed Green’s Thoracic Fusion, opined on the impact of the fusion on the injuries
attributable to the 2006 Accident:
           The patient specifically asked me whether I would recommend that he return to
           logging again, and my recommendation is that he should not return to logging or
           heavy labor again because of his prior lumbar fusion and then the fusion that I
           performed at the central disc herniation of T12-Ll. The only motion segment that
           remains in his back is at Ll-2 and L2-3, and with heavy work, those will certainly
           begin to fail and most likely will require surgery in the future.
Likewise, Dr. McNulty offered a similar opinion:
           I have reviewed the FCE[5] and agree with the findings. Mr. Green has a fusion at
           T12-Ll and L3-5. Because of those fusions, he has increased stress between L1
           and 3. He should not engage in heavy physical activities such as logging. He is
           more suited to work in a light duty job category as outlined in the FCE.
           The Commission rejected ISIF’s argument that the 2006 Accident, standing alone,
rendered Green totally and permanently disabled. The Commission found that evidence
indicating that Green was unhampered prior to the 2006 Accident was not credible. The
Commission found the testimony of two vocational rehabilitation consultants, Dr. Nancy Collins
and Dan Brownell, to be more credible in determining that Green’s Thoracic Fusion had limited
his ability to find employment.
           ISIF focuses on two sentences in the Commission’s decision to argue the Commission
failed to apply the “but for” test. Those two sentences are:
           Therefore, per Drs. Ganz and McNulty, the fact that Claimant has a preexisting
           T12-Ll fusion increases the risk that he will have further problems from L3-5
           fusion unless he observes certain prophylactic limitations/restrictions. We believe
           this demonstrates that Claimant’s pre-existing thoracic spine condition does


5
    FCE refers to a Functional Capacity Evaluation performed by Pinnacle Physical Therapy and Sports Medicine.

                                                         11
       combine with the effects of the work accident to contribute to Claimant’s total
       and permanent disability.
While these two sentences do not use the proper “but for” test language, the whole of the
Commission’s decision on this issue clearly employs the correct test.
       ISIF also contends the Commission’s decision is not supported by substantial and
competent evidence because a physician did not give expert testimony on the “but for” causation
issue. “Claimants must prove causation with expert medical testimony, but the Commission may
consider other evidence as well.” Hope v. Indus. Special Indemn. Fund, 157 Idaho 567, 572, 338
P.3d 546, 551 (2014). The Commission cannot “inject its own unqualified medical opinion to
draw a conclusion from the evidence.” Corgatelli v. Steel W., Inc., 157 Idaho 287, 297, 335 P.3d
1150, 1160 (2014). There is no requirement that a precise “but for” question be directed to a
physician as a prerequisite to ISIF liability. The issue whether a total permanent disability is the
result of the combined effects of a pre-existing and work-related injury is more expansive than a
simple medical inquiry because a determination of total permanent disability necessarily takes
into account non-medical factors. See I.C. § 72-430. Dr. Ganz and Dr. McNulty established that,
because of Green’s Thoracic Fusion and the other fusions, there are only two small motion
segments left in his spine that will quickly fail with heavy lifting. The Commission connected
this medical evidence with testimony from vocational rehabilitation experts to determine that,
but for Green’s pre-existing Thoracic Fusion, he would not be totally and permanently disabled.
We hold that the Commission’s finding that Green’s thoracic spine condition “combined with”
the previous industrial injuries to render Green totally and permanently disabled is supported by
substantial and competent evidence.
D. Employer/Surety’s failure to cross-appeal precludes our consideration of an issue they
   wish for this Court to address on appeal.
       Surety/Employee contends the Commission erred in failing to give recognition to a 5%
pre-existing lumbar impairment that was recognized in two lump sum agreements that were
approved by the Commission in 1988 and 2005. They argue the Commission erred by not
including the pre-existing lumbar impairment in addition to the 20% impairment attributed to the
Thoracic Fusion. ISIF responds that this issue is not properly before this Court because
Employer/Surety failed to cross-appeal.
       ISIF is correct. “In Idaho, a timely notice of appeal or cross-appeal is a jurisdictional
prerequisite to challenge a determination made by a lower court. Failure to timely file such a

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notice shall cause automatic dismissal of the issue on appeal.” Hamilton v. Alpha Servs., LLC,
158 Idaho 683, 693, 351 P.3d 611, 621 (2015) (quoting Miller v. Bd. of Trustees, 132 Idaho 244,
248, 970 P.2d 512, 516 (1998)). Here, Employer/Surety seeks affirmative relief, asking that ISIF
be required to bear an increased share of Green’s disability benefits. Because Employer/Surety
failed to fulfill the jurisdictional prerequisite of filing a cross-appeal, we may not address this
issue on appeal.
                                      IV. CONCLUSION
       We affirm the Commission’s decision. Given that both parties prevailed in part on claims
advanced in this appeal, we do not award costs on appeal.

       Chief Justice J. JONES and Justices EISMANN, BURDICK and W. JONES, CONCUR.




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